Data transmission method and data transmission device

Abstract

The present application discloses a data transmission method and a data transmission device. A simple target polynomial is designed to generate pilot symbols. Accordingly, a simple hardware structure can be used for implementation. Furthermore, the generated pilot symbols have good autocorrelation and cross-correlation characteristics and maintain DC balance, which helps the receiver restore signal quality. Specifically, the generated data frame includes N symbols in a certain polarization direction, one pilot symbol at a fixed position for every M consecutive symbols among the N symbols, and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1. The Q pilot symbols are generated using the target polynomial and a seed, each of which is one of -A-Aj, -A+Aj, A-Aj, and A+Aj. The Q pilot symbols maintain DC balance, the degree of the target polynomial is less than or equal to 10, and the number of terms in the target polynomial is between 2 and 8.

Description

[Technical Field]

[0001] Technical Field The present application relates to the field of communications, and in particular to a data transmission method and device. [Background technology]

[0002] With the continuous promotion of 5G, cloud computing, big data, and artificial intelligence, high-speed optical transport networks are evolving toward higher capacity, packetization, and intelligence. Coherent optical communication systems use the amplitude, phase, polarization, and frequency of light waves to carry information. To combat optical signal distortion caused by dispersion, polarization-dependent degradation, noise, nonlinear effects, and other factors in the transmission process and maintain long-distance transmission, coherent optical communication systems usually add some designed fixed symbol sequences to the transmitted symbol sequence, so that the receiver can recover the transmitted symbols.

[0003] Existing transmission symbol sequences are mainly used in 400 Gbps scenarios and cannot adapt to future scenarios exceeding 400 Gbps (including 600 Gbps, 800 Gbps, and the like). Furthermore, the prior art solutions have the problem of high hardware implementation complexity, which needs to be urgently solved in the future. Summary of the Invention

[0004] The embodiments of the present application provide a data transmission method and a data transmission device. A simple target polynomial is designed to generate pilot symbols. Correspondingly, a simple hardware structure can be used for implementation. Furthermore, the generated pilot symbols have good autocorrelation and cross-correlation characteristics and maintain DC balance, which helps the receiving side restore signal quality.

[0005] According to a first aspect, an embodiment of the present application provides a data transmission method. The method applied to the transmitting side includes the following steps: First, a data frame is generated. In a certain polarization direction, the data frame includes N symbols, one pilot symbol at a certain fixed position for every M consecutive symbols among the N symbols, and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1. The Q pilot symbols are generated using a target polynomial and a seed, each pilot symbol being one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number, the Q pilot symbols are DC-balanced, the degree of the target polynomial is less than or equal to 10, and the number of terms of the target polynomial is greater than or equal to 2 and less than or equal to 8. Then, the data frame is transmitted.

[0006] In this implementation, in a data frame containing N symbols, every M consecutive symbols contain a pilot symbol at a fixed position and M-1 payload symbols, where N=M×Q. The Q pilot symbols in the data frame are generated using a target polynomial and a seed, where the Q pilot symbols are DC-balanced, the degree of the target polynomial is 10 or less, and the number of terms in the target polynomial is between 2 and 8. It can be seen that a simple target polynomial is designed in this application to generate the pilot symbols. Correspondingly, a simple hardware structure can be used for implementation. Furthermore, the pilot symbols generated by the above method have good autocorrelation and cross-correlation properties and are DC-balanced, which helps the receiver restore signal quality.

[0007] In some possible implementations, the target polynomial is one of the following: x^9+x^4+x^3+x+1; x^9+x^5+x^4+x+1; x^9+x^8+x^5+x^4+1; x^9+x^8+x^6+x^5+1; x^10+x^4+x^3+x+1; x^10+x^5+x^2+x+1; x^10+x^8+x^5+x+1; x^10+x^9+x^4+x+1; x^10+x^9+x^5+x^2+1; x^10+x^9+x^6+x+1; x^10+x^9+x^7+x^6+1; x^10+x^9+x^8+x^5+1; x^10+x^8+x^6+x^5+x^3+x+1; x^10+x^8+x^7+x^3+x^2+x+1; x^10+x^8+x^7+x^6+x^2+x+1; x^10+x^9+x^7+x^5+x^4+x^2+1; x^10+x^9+x^8+x^4+x^3+x^2+1; or x^10+x^9+x^8+x^7+x^3+x^2+1.

[0008] In some possible implementations, the target polynomial is one of the following: x^10+x^9+x^8+x^7+x^4+x+1; or x^10+x^9+x^6+x^3+x^2+x+1.

[0009] It should be understood that the above polynomials have good differential autocorrelation and differential cross-correlation characteristics, and can achieve good correlation effect even when there is a frequency difference between the transmitting laser and the receiving laser.

[0010] In some possible implementations, each pilot symbol is located at the beginning of M consecutive symbols in which the pilot symbols are located.

[0011] In some possible implementations, the sequence containing Q pilot symbols in the first polarization direction is different from the sequence containing Q pilot symbols in the second polarization direction, and the first polarization direction and the second polarization direction are orthogonal to each other, which avoids the problem that the receiver cannot distinguish between the two polarization directions in actual transmission.

[0012] In some possible implementations, N=6144, M=64, Q=96, and the correspondence between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is one of the following: Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x002, and seed in second polarization direction: 0x115; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x002, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x049, and seed in second polarization direction: 0x115; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x049, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x115, and seed in second polarization direction: 0x08D; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x08D, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x11E; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x11E; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x11E, and seed in second polarization direction: 0x175; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x175, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x175, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x16A, and seed in second polarization direction: 0x1E1; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x16A, and seed in second polarization direction: 0x1C3; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1E1, and seed in second polarization direction: 0x069; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1E1, and seed in second polarization direction: 0x113; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x069, and seed in second polarization direction: 0x1C3; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1C3, and seed in second polarization direction: 0x113; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x0E6, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x3DC, and seed in second polarization direction: 0x36A; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x35E; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x1AF; Target polynomial: x^10+x^8+x^5+x+1, seed in first polarization direction: 0x1FD, and seed in second polarization direction: 0x3A7; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x12A, and seed in second polarization direction: 0x039; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x12A, and seed in second polarization direction: 0x107; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x039, and seed in second polarization direction: 0x295; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x295, and seed in second polarization direction: 0x107; Target polynomial: x^10+x^9+x^5+x^2+1, seed in first polarization direction: 0x26A, and seed in second polarization direction: 0x03A; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x379; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x3EF; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x2D1, and seed in second polarization direction: 0x379; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x2D1, and seed in second polarization direction: 0x3EF; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x1E2; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x170, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x0B8, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x299, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x354, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x17C, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x1AA, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x06A, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x3E6, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2A9, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2F9, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x0D5, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x1F3; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x14B; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x297; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x12F; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x3AC; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed for first polarization direction: 0x320, and seed for second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x3AC; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x3AC, and seed in second polarization direction: 0x01A; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1B0, and seed in second polarization direction: 0x3F4; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1B0, and seed in second polarization direction: 0x1FA; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x3F4, and seed in second polarization direction: 0x13D; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1FA, and seed in second polarization direction: 0x13D; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x35C, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x0DC, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x33A, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x26E, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x2B9; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x1B9; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x275; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x39D; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x173; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x39B; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x337; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed for first polarization direction: 0x0C6, and seed for second polarization direction: 0x157; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x0C6, and seed in second polarization direction: 0x2D7; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x263, and seed in second polarization direction: 0x157; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x263, and seed in second polarization direction: 0x2D7; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x130; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x298; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x34C; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x130, and seed in second polarization direction: 0x014; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x130, and seed in second polarization direction: 0x282; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x298, and seed in second polarization direction: 0x014; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x298, and seed in second polarization direction: 0x282; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x34C; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x34C, and seed in second polarization direction: 0x282; or Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed for first polarization direction: 0x282, and seed for second polarization direction: 0x261.

[0013] In some possible implementations, N=6144, M=64, Q=96, and the correspondence between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is one of the following: Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x1E1; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x094, and seed in second polarization direction: 0x02B; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x058, and seed in second polarization direction: 0x3CC; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x316; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x18E; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x163; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x152, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x2A4, and seed in second polarization direction: 0x316; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x0B4, and seed in second polarization direction: 0x2D1; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x05A; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x05A, and seed in second polarization direction: 0x2D1; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x128, and seed in second polarization direction: 0x12A; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x250, and seed in second polarization direction: 0x12A; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x250, and seed in second polarization direction: 0x295; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x39C, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x18E, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x36E, and seed in second polarization direction: 0x239; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x36E, and seed in second polarization direction: 0x0E7; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x232, and seed in second polarization direction: 0x36A; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x119; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed for first polarization direction: 0x282, and seed for second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x2A6, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x196, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x259; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x380, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x380, and seed in second polarization direction: 0x081; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x375; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x353; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x2FF; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x3FF; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x301, and seed in second polarization direction: 0x2D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x301, and seed in second polarization direction: 0x3D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x3D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x0AD; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x19C, and seed in second polarization direction: 0x301; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x186; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x1A3; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x346; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x1C5; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x063; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x1C5, and seed in second polarization direction: 0x327; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x240, and seed in second polarization direction: 0x3C4; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x103; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x226; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x165; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x165, and seed in second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed for first polarization direction: 0x266, and seed for second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x3E2; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x0C4, and seed in second polarization direction: 0x226; or Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, Seed in first polarization direction: 0x1D8, and Seed in second polarization direction: 0x2D9.

[0014] It should be understood that the above polynomials and seeds have good differential autocorrelation and cross-correlation properties, and can achieve good correlation effects even when there is a frequency difference between the transmitting laser and the receiving laser.

[0015] In some possible implementations, N=6144, M=64, Q=96, the target polynomial is x^9+x^4+x^3+x+1, the seed for the first polarization direction is 0x049, the seed for the second polarization direction is 0x115, and the first polarization direction and the second polarization direction are orthogonal to each other.

[0016] The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A+-Aj,-A+Aj,-A+Aj,-A+ Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A +Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj, and A+Aj.

[0017] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A-Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,- A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,A+Aj,- -A+Aj,A-Aj,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,and A+Aj.

[0018] In some possible implementations, N=6144, M=64, Q=96, the target polynomial expression is x^10+x^9+x^4+x+1, the sequence in the 1st bias direction is 0x12A, and the 2nd bias direction is 0x039.

[0019] The 96 pilot symbols in the 1st wave direction are as follows: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj,A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,- j,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, and -A+Aj.

[0020] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A- Aj,A+Aj,A-Aj,-A+Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A +Aj,-A-Aj,A+Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,-A+Aj, A-Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,-A-Aj,A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,A+Aj,A -Aj,A+Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A- Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,and A+Aj.

[0021] In some possible implementations, the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in multiple optical signals for transmission.

[0022] In some possible implementations, W data frames are carried by W optical signals, where any two of the W optical signals have different wavelengths. Alternatively, all W optical signals have the same wavelength, and each W optical signal is transmitted over W optical fibers.

[0023] In some possible implementations, the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other. In the first polarization direction, Q pilot symbols in the first data frame are generated using a first target polynomial and a first seed; and in the second polarization direction, Q pilot symbols in the first data frame are generated using the first target polynomial and a second seed. In the first polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a fourth seed.

[0024] In some possible implementations, the first pilot symbol sequence in the first data frame is the same as the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0025] In some possible implementations, the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

[0026] In some possible implementations, the first pilot symbol sequence in the first data frame is different from the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0027] In some possible implementations, the first target polynomial is the same as the second target polynomial, and any two of the first seed, second seed, third seed, and fourth seed are different from each other.

[0028] In some possible implementations, the first target polynomial is different from the second target polynomial.

[0029] In some possible implementations, the number of consecutive identical pilot symbols in a data frame in a given polarization direction is four or less.

[0030] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is 16QAM, with A=-1, 1, -3, 3, -√5, or √5.

[0031] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is QPSK, with A=-1 or 1.

[0032] According to a second aspect, an embodiment of the present application provides a data transmission method. The method includes the following steps: First, a data frame is generated. In a certain polarization direction, the data frame includes N symbols, one pilot symbol at a certain fixed position for every M consecutive symbols among the N symbols, and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1. The Q pilot symbols are generated using a target polynomial and a seed, each pilot symbol being one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number. The Q pilot symbols are DC-balanced, and the difference between any two of the numbers of pilot symbols in the data frame, which are -A-Aj, -A+Aj, A-Aj, and A+Aj, respectively, is 2 or less. Then, the data frame is transmitted.

[0033] In implementation, the difference between any two of the numbers of pilot symbols in a data frame that are -A-Aj, -A+Aj, A-Aj, and A+Aj is less than or equal to 2. Furthermore, the number of pilot symbols that are -A-Aj is the same as the number of pilot symbols that are A+Aj, and the number of pilot symbols that are -A+Aj is the same as the number of pilot symbols that are A-Aj. This effectively ensures that the number of symbols in each polarization direction is approximately balanced, further ensuring that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0034] In some possible implementations, for a given polarization direction, in a data frame: The number of pilot symbols is -A-Aj.

[0035]

number

[0036]

number

[0037]

number

[0038]

number

[0039] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0040]

number

[0041]

number

[0042]

number

[0043]

number

[0044] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0045]

number

[0046]

number

[0047]

number

[0048]

number

[0049] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0050]

number

[0051]

number

[0052]

number

[0053]

number

[0054]

number

[0055] In some possible implementations, N=6144, M=64, Q=96, the target polynomial is x^9+x^8+x^5+x^4+1, the seed for the first polarization direction is 0x175, the seed for the second polarization direction is 0x03D, and the first polarization direction and the second polarization direction are orthogonal to each other.

[0056] In some possible implementations, the 96 pilot symbols in the first polarization direction are, in order: A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,-A+A-Aj,A-Aj,A-Aj,A-Aj,-A+Aj, -A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj j,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj j,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj, and -A-Aj.

[0057] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj, -A-Aj,-A+Aj,A-Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,A -Aj,-A+Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj, -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A-Aj,A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A-Aj,A+Aj, and A+Aj.

[0058] In some possible implementations, in the 1st wave direction, in the data frame, -A-Also the number of pilot symbols

[0059]

number

[0060]

number

[0061]

number

[0062]

number

[0063]

number

[0064]

number

[0065]

number

[0066]

number

[0067] Alternatively, in the first polarization direction, in the data frame, The number of pilot symbols is -A-Aj.

[0068]

number

[0069]

number

[0070]

number

[0071]

number

[0072]

number

[0073]

number

[0074]

number

[0075]

number

[0076]

number

[0077] In implementation, in the two polarization directions, the total number of pilot symbols for -A-Aj is Q / 2, the total number of pilot symbols for -A+Aj is Q / 2, the total number of pilot symbols for A-Aj is Q / 2, and the total number of pilot symbols for A+Aj is Q / 2. This effectively ensures a balance between the symbol quantities, and further ensures that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0078] In some possible implementations, N=6144, M=64, Q=96, and the first and second polarization directions are orthogonal to each other.

[0079] The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A+-Aj,-A+Aj,-A+Aj,-A+ Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A +Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj, and A+Aj.

[0080] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A-Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,- A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,A+Aj,- -A+Aj,A-Aj,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,and A+Aj.

[0081] In some possible implementations, N=6144, M=64, Q=96, and the 1st wave direction and the 2nd wave direction are in direct contact with each other.

[0082] The 96 pilot symbols in the 1st wave direction are as follows: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj,A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,- j,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, and -A+Aj.

[0083] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A- Aj,A+Aj,A-Aj,-A+Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A +Aj,-A-Aj,A+Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,-A+Aj, A-Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,-A-Aj,A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,A+Aj,A -Aj,A+Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A- Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,and A+Aj.

[0084] In some possible implementations, the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in multiple optical signals for transmission.

[0085] In some possible implementations, W data frames are carried by W optical signals, where any two of the W optical signals have different wavelengths. Alternatively, all W optical signals have the same wavelength, and each W optical signal is transmitted over W optical fibers.

[0086] In some possible implementations, the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other. In the first polarization direction, Q pilot symbols in the first data frame are generated using a first target polynomial and a first seed; and in the second polarization direction, Q pilot symbols in the first data frame are generated using the first target polynomial and a second seed. In the first polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a fourth seed.

[0087] In some possible implementations, the first pilot symbol sequence in the first data frame is the same as the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0088] In some possible implementations, the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

[0089] In some possible implementations, the first pilot symbol sequence in the first data frame is different from the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0090] In some possible implementations, the first target polynomial is the same as the second target polynomial, and any two of the first seed, second seed, third seed, and fourth seed are different from each other.

[0091] In some possible implementations, the first target polynomial is different from the second target polynomial.

[0092] In some possible implementations, the number of consecutive identical pilot symbols in a data frame in a given polarization direction is four or less.

[0093] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is 16QAM, with A=-1, 1, -3, 3, -√5, or √5.

[0094] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is QPSK, with A=-1 or 1.

[0095] According to a third aspect, an embodiment of the present application provides a data transmission method. The method applied to the receiving side includes the following steps: First, a data frame is received. In a certain polarization direction, the data frame includes N symbols, one pilot symbol at a certain fixed position for every M consecutive symbols among the N symbols, and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1. The Q pilot symbols are generated using a target polynomial and a seed, each pilot symbol being one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number. The Q pilot symbols are DC-balanced, the degree of the target polynomial is less than or equal to 10, and the number of terms of the target polynomial is greater than or equal to 2 and less than or equal to 8. Then, the data frame is processed.

[0096] In this implementation, in a data frame containing N symbols, every M consecutive symbols contain a pilot symbol at a fixed position and M-1 payload symbols, where N=M×Q. The Q pilot symbols in the data frame are generated using a target polynomial and a seed, where the Q pilot symbols are DC-balanced, the degree of the target polynomial is 10 or less, and the number of terms in the target polynomial is between 2 and 8. It can be seen that a simple target polynomial is designed in this application to generate the pilot symbols. Correspondingly, a simple hardware structure can be used for implementation. Furthermore, the pilot symbols generated by the above method have good autocorrelation and cross-correlation properties and are DC-balanced, which helps the receiver restore signal quality.

[0097] In some possible implementations, the target polynomial is one of the following: x^9+x^4+x^3+x+1; x^9+x^5+x^4+x+1; x^9+x^8+x^5+x^4+1; x^9+x^8+x^6+x^5+1; x^10+x^4+x^3+x+1; x^10+x^5+x^2+x+1; x^10+x^8+x^5+x+1; x^10+x^9+x^4+x+1; x^10+x^9+x^5+x^2+1; x^10+x^9+x^6+x+1; x^10+x^9+x^7+x^6+1; x^10+x^9+x^8+x^5+1; x^10+x^8+x^6+x^5+x^3+x+1; x^10+x^8+x^7+x^3+x^2+x+1; x^10+x^8+x^7+x^6+x^2+x+1; x^10+x^9+x^7+x^5+x^4+x^2+1; x^10+x^9+x^8+x^4+x^3+x^2+1; or x^10+x^9+x^8+x^7+x^3+x^2+1.

[0098] In some possible implementations, the target polynomial is one of the following: x^10+x^9+x^8+x^7+x^4+x+1; or x^10+x^9+x^6+x^3+x^2+x+1.

[0099] It should be understood that the above polynomials have good differential autocorrelation and cross-correlation properties, and can achieve good correlation effect even when there is a frequency difference between the transmitting laser and the receiving laser.

[0100] In some possible implementations, each pilot symbol is located at the beginning of M consecutive symbols in which the pilot symbols are located.

[0101] In some possible implementations, the sequence containing Q pilot symbols in the first polarization direction is different from the sequence containing Q pilot symbols in the second polarization direction, and the first polarization direction and the second polarization direction are orthogonal to each other, which avoids the problem that the receiver cannot distinguish between the two polarization directions in actual transmission.

[0102] In some possible implementations, N=6144, M=64, Q=96, and the correspondence between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is one of the following: Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x002, and seed in second polarization direction: 0x115; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x002, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x049, and seed in second polarization direction: 0x115; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x049, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x115, and seed in second polarization direction: 0x08D; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x08D, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x11E; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x11E; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x11E, and seed in second polarization direction: 0x175; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x175, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x175, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x16A, and seed in second polarization direction: 0x1E1; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x16A, and seed in second polarization direction: 0x1C3; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1E1, and seed in second polarization direction: 0x069; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1E1, and seed in second polarization direction: 0x113; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x069, and seed in second polarization direction: 0x1C3; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1C3, and seed in second polarization direction: 0x113; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x0E6, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x3DC, and seed in second polarization direction: 0x36A; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x35E; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x1AF; Target polynomial: x^10+x^8+x^5+x+1, seed in first polarization direction: 0x1FD, and seed in second polarization direction: 0x3A7; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x12A, and seed in second polarization direction: 0x039; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x12A, and seed in second polarization direction: 0x107; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x039, and seed in second polarization direction: 0x295; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x295, and seed in second polarization direction: 0x107; Target polynomial: x^10+x^9+x^5+x^2+1, seed in first polarization direction: 0x26A, and seed in second polarization direction: 0x03A; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x379; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x3EF; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x2D1, and seed in second polarization direction: 0x379; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x2D1, and seed in second polarization direction: 0x3EF; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x1E2; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x170, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x0B8, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x299, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x354, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x17C, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x1AA, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x06A, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x3E6, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2A9, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2F9, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x0D5, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x1F3; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x14B; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x297; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x12F; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x3AC; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed for first polarization direction: 0x320, and seed for second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x3AC; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x3AC, and seed in second polarization direction: 0x01A; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1B0, and seed in second polarization direction: 0x3F4; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1B0, and seed in second polarization direction: 0x1FA; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x3F4, and seed in second polarization direction: 0x13D; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1FA, and seed in second polarization direction: 0x13D; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x35C, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x0DC, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x33A, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x26E, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x2B9; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x1B9; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x275; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x39D; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x173; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x39B; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x337; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed for first polarization direction: 0x0C6, and seed for second polarization direction: 0x157; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x0C6, and seed in second polarization direction: 0x2D7; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x263, and seed in second polarization direction: 0x157; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x263, and seed in second polarization direction: 0x2D7; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x130; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x298; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x34C; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x130, and seed in second polarization direction: 0x014; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x130, and seed in second polarization direction: 0x282; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x298, and seed in second polarization direction: 0x014; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x298, and seed in second polarization direction: 0x282; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x34C; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x34C, and seed in second polarization direction: 0x282; or Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed for first polarization direction: 0x282, and seed for second polarization direction: 0x261.

[0103] In some possible implementations, N=6144, M=64, Q=96, and the correspondence between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is one of the following: Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x1E1; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x094, and seed in second polarization direction: 0x02B; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x058, and seed in second polarization direction: 0x3CC; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x316; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x18E; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x163; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x152, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x2A4, and seed in second polarization direction: 0x316; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x0B4, and seed in second polarization direction: 0x2D1; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x05A; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x05A, and seed in second polarization direction: 0x2D1; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x128, and seed in second polarization direction: 0x12A; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x250, and seed in second polarization direction: 0x12A; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x250, and seed in second polarization direction: 0x295; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x39C, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x18E, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x36E, and seed in second polarization direction: 0x239; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x36E, and seed in second polarization direction: 0x0E7; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x232, and seed in second polarization direction: 0x36A; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x119; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed for first polarization direction: 0x282, and seed for second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x2A6, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x196, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x259; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x380, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x380, and seed in second polarization direction: 0x081; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x375; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x353; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x2FF; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x3FF; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x301, and seed in second polarization direction: 0x2D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x301, and seed in second polarization direction: 0x3D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x3D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x0AD; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x19C, and seed in second polarization direction: 0x301; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x186; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x1A3; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x346; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x1C5; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x063; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x1C5, and seed in second polarization direction: 0x327; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x240, and seed in second polarization direction: 0x3C4; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x103; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x226; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x165; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x165, and seed in second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed for first polarization direction: 0x266, and seed for second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x3E2; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x0C4, and seed in second polarization direction: 0x226; or Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, Seed in first polarization direction: 0x1D8, and Seed in second polarization direction: 0x2D9.

[0104] It should be understood that the above polynomials and seeds have good differential autocorrelation and cross-correlation properties, and can achieve good correlation effects even when there is a frequency difference between the transmitting laser and the receiving laser.

[0105] In some possible implementations, N=6144, M=64, Q=96, the target polynomial is x^9+x^4+x^3+x+1, the seed for the first polarization direction is 0x049, the seed for the second polarization direction is 0x115, and the first polarization direction and the second polarization direction are orthogonal to each other.

[0106] The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A+-Aj,-A+Aj,-A+Aj,-A+ Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A +Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj, and A+Aj.

[0107] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A-Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,- A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,A+Aj,- -A+Aj,A-Aj,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,and A+Aj.

[0108] In some possible implementations, N=6144, M=64, Q=96, the target polynomial expression is x^10+x^9+x^4+x+1, the sequence in the 1st bias direction is 0x12A, and the 2nd bias direction is 0x039.

[0109] The 96 pilot symbols in the 1st wave direction are as follows: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj,A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,- j,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, and -A+Aj.

[0110] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A- Aj,A+Aj,A-Aj,-A+Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A +Aj,-A-Aj,A+Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,-A+Aj, A-Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,-A-Aj,A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,A+Aj,A -Aj,A+Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A- Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,and A+Aj.

[0111] In some possible implementations, the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in multiple optical signals for transmission.

[0112] In some possible implementations, W data frames are carried by W optical signals, where any two of the W optical signals have different wavelengths. Alternatively, all W optical signals have the same wavelength, and each W optical signal is transmitted over W optical fibers.

[0113] In some possible implementations, the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other. In the first polarization direction, Q pilot symbols in the first data frame are generated using a first target polynomial and a first seed; and in the second polarization direction, Q pilot symbols in the first data frame are generated using the first target polynomial and a second seed. In the first polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a fourth seed.

[0114] In some possible implementations, the first pilot symbol sequence in the first data frame is the same as the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0115] In some possible implementations, the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

[0116] In some possible implementations, the first pilot symbol sequence in the first data frame is different from the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0117] In some possible implementations, the first target polynomial is the same as the second target polynomial, and any two of the first seed, second seed, third seed, and fourth seed are different from each other.

[0118] In some possible implementations, the first target polynomial is different from the second target polynomial.

[0119] In some possible implementations, the number of consecutive identical pilot symbols in a data frame in a given polarization direction is four or less.

[0120] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is 16QAM, with A=-1, 1, -3, 3, -√5, or √5.

[0121] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is QPSK, with A=-1 or 1.

[0122] According to a fourth aspect, an embodiment of the present application provides a data transmission method. The method applied to a receiving side includes the following steps: First, a data frame is received. In a certain polarization direction, the data frame includes N symbols, and each of M consecutive symbols in the N symbols includes one pilot symbol at a certain fixed position and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1. The Q pilot symbols are generated by using a target polynomial and a seed, and each pilot symbol is one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number. The Q pilot symbols are DC-balanced. The difference between the numbers of pilot symbols in a data frame, -A-Aj, -A+Aj, A-Aj, and A+Aj, respectively, is 2 or less. The data frame is then processed.

[0123] In implementation, the difference between any two of the numbers of pilot symbols in a data frame that are -A-Aj, -A+Aj, A-Aj, and A+Aj is less than or equal to 2. Furthermore, the number of pilot symbols that are -A-Aj is the same as the number of pilot symbols that are A+Aj, and the number of pilot symbols that are -A+Aj is the same as the number of pilot symbols that are A-Aj. This effectively ensures that the number of symbols in each polarization direction is approximately balanced, further ensuring that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0124] In some possible implementations, for a given polarization direction, in a data frame: The number of pilot symbols is -A-Aj.

[0125]

number

[0126]

number

[0127]

number

[0128]

number

[0129] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0130]

number

[0131]

number

[0132]

number

[0133]

number

[0134] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0135]

number

[0136]

number

[0137]

number

[0138]

number

[0139] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0140]

number

[0141]

number

[0142]

number

[0143]

number

[0144]

number

[0145] In some possible implementations, N=6144, M=64, Q=96, the target polynomial is x^9+x^8+x^5+x^4+1, the seed for the first polarization direction is 0x175, the seed for the second polarization direction is 0x03D, and the first polarization direction and the second polarization direction are orthogonal to each other.

[0146] In some possible implementations, the 96 pilot symbols in the first polarization direction are, in order: A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,-A+A-Aj,A-Aj,A-Aj,A-Aj,-A+Aj, -A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj j,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj j,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj, and -A-Aj.

[0147] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj, -A-Aj,-A+Aj,A-Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,A -Aj,-A+Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj, -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A-Aj,A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A-Aj,A+Aj, and A+Aj.

[0148] In some possible implementations, in the 1st wave direction, in the data frame, -A-Also the number of pilot symbols

[0149]

number

[0150]

number

[0151]

number

[0152]

number

[0153]

number

[0154]

number

[0155]

number

[0156]

number

[0157] Alternatively, in the first polarization direction, in the data frame, The number of pilot symbols is -A-Aj.

[0158]

number

[0159]

number

[0160]

number

[0161]

number

[0162]

number

[0163]

number

[0164]

number

[0165]

number

[0166]

number

[0167] In implementation, in the two polarization directions, the total number of pilot symbols for -A-Aj is Q / 2, the total number of pilot symbols for -A+Aj is Q / 2, the total number of pilot symbols for A-Aj is Q / 2, and the total number of pilot symbols for A+Aj is Q / 2. This effectively ensures a balance between the symbol quantities, and further ensures that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0168] In some possible implementations, N=6144, M=64, Q=96, and the first and second polarization directions are orthogonal to each other.

[0169] The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A+-Aj,-A+Aj,-A+Aj,-A+ Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A +Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj, and A+Aj.

[0170] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A-Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,- A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,A+Aj,- -A+Aj,A-Aj,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,and A+Aj.

[0171] In some possible implementations, N=6144, M=64, Q=96, and the 1st wave direction and the 2nd wave direction are in direct contact with each other.

[0172] The 96 pilot symbols in the 1st wave direction are as follows: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj,A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,- j,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, and -A+Aj.

[0173] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A- Aj,A+Aj,A-Aj,-A+Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A +Aj,-A-Aj,A+Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,-A+Aj, A-Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,-A-Aj,A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,A+Aj,A -Aj,A+Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A- Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,and A+Aj.

[0174] In some possible implementations, the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in multiple optical signals for transmission.

[0175] In some possible implementations, W data frames are carried by W optical signals, where any two of the W optical signals have different wavelengths. Alternatively, all W optical signals have the same wavelength, and each W optical signal is transmitted over W optical fibers.

[0176] In some possible implementations, the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other. In the first polarization direction, Q pilot symbols in the first data frame are generated using a first target polynomial and a first seed; and in the second polarization direction, Q pilot symbols in the first data frame are generated using the first target polynomial and a second seed. In the first polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a fourth seed.

[0177] In some possible implementations, the first pilot symbol sequence in the first data frame is the same as the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0178] In some possible implementations, the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

[0179] In some possible implementations, the first pilot symbol sequence in the first data frame is different from the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0180] In some possible implementations, the first target polynomial is the same as the second target polynomial, and any two of the first seed, second seed, third seed, and fourth seed are different from each other.

[0181] In some possible implementations, the first target polynomial is different from the second target polynomial.

[0182] In some possible implementations, the number of consecutive identical pilot symbols in a data frame in a given polarization direction is four or less.

[0183] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is 16QAM, with A=-1, 1, -3, 3, -√5, or √5.

[0184] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is QPSK, with A=-1 or 1.

[0185] According to a fifth aspect, an embodiment of the present application provides a data transmission device. The data transmission device includes a processing unit and a transmitting unit. The processing unit is configured to generate a data frame. In a certain polarization direction, the data frame includes N symbols, one pilot symbol at a certain fixed position for every M consecutive symbols among the N symbols, and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1. The Q pilot symbols are generated using a target polynomial and a seed, each pilot symbol being one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number. The Q pilot symbols are DC-balanced, the degree of the target polynomial is less than or equal to 10, and the number of terms of the target polynomial is greater than or equal to 2 and less than or equal to 8. The transmitting unit is configured to transmit the data frame.

[0186] In this implementation, in a data frame containing N symbols, every M consecutive symbols contain a pilot symbol at a fixed position and M-1 payload symbols, where N=M×Q. The Q pilot symbols in the data frame are generated using a target polynomial and a seed, where the Q pilot symbols are DC-balanced, the degree of the target polynomial is 10 or less, and the number of terms in the target polynomial is between 2 and 8. It can be seen that a simple target polynomial is designed in this application to generate the pilot symbols. Correspondingly, a simple hardware structure can be used for implementation. Furthermore, the pilot symbols generated by the above method have good autocorrelation and cross-correlation properties and are DC-balanced, which helps the receiver restore signal quality.

[0187] In some possible implementations, the target polynomial is one of the following: x^9+x^4+x^3+x+1; x^9+x^5+x^4+x+1; x^9+x^8+x^5+x^4+1; x^9+x^8+x^6+x^5+1; x^10+x^4+x^3+x+1; x^10+x^5+x^2+x+1; x^10+x^8+x^5+x+1; x^10+x^9+x^4+x+1; x^10+x^9+x^5+x^2+1; x^10+x^9+x^6+x+1; x^10+x^9+x^7+x^6+1; x^10+x^9+x^8+x^5+1; x^10+x^8+x^6+x^5+x^3+x+1; x^10+x^8+x^7+x^3+x^2+x+1; x^10+x^8+x^7+x^6+x^2+x+1; x^10+x^9+x^7+x^5+x^4+x^2+1; x^10+x^9+x^8+x^4+x^3+x^2+1; or x^10+x^9+x^8+x^7+x^3+x^2+1.

[0188] In some possible implementations, the target polynomial is one of the following: x^10+x^9+x^8+x^7+x^4+x+1; or x^10+x^9+x^6+x^3+x^2+x+1.

[0189] It should be understood that the above polynomials have good differential autocorrelation and cross-correlation properties, and can achieve good correlation effect even when there is a frequency difference between the transmitting laser and the receiving laser.

[0190] In some possible implementations, each pilot symbol is located at the beginning of M consecutive symbols in which the pilot symbols are located.

[0191] In some possible implementations, the sequence containing Q pilot symbols in the first polarization direction is different from the sequence containing Q pilot symbols in the second polarization direction, and the first polarization direction and the second polarization direction are orthogonal to each other, which avoids the problem that the receiver cannot distinguish between the two polarization directions in actual transmission.

[0192] In some possible implementations, N=6144, M=64, Q=96, and the correspondence between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is one of the following: Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x002, and seed in second polarization direction: 0x115; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x002, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x049, and seed in second polarization direction: 0x115; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x049, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x115, and seed in second polarization direction: 0x08D; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x08D, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x11E; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x11E; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x11E, and seed in second polarization direction: 0x175; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x175, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x175, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x16A, and seed in second polarization direction: 0x1E1; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x16A, and seed in second polarization direction: 0x1C3; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1E1, and seed in second polarization direction: 0x069; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1E1, and seed in second polarization direction: 0x113; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x069, and seed in second polarization direction: 0x1C3; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1C3, and seed in second polarization direction: 0x113; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x0E6, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x3DC, and seed in second polarization direction: 0x36A; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x35E; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x1AF; Target polynomial: x^10+x^8+x^5+x+1, seed in first polarization direction: 0x1FD, and seed in second polarization direction: 0x3A7; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x12A, and seed in second polarization direction: 0x039; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x12A, and seed in second polarization direction: 0x107; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x039, and seed in second polarization direction: 0x295; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x295, and seed in second polarization direction: 0x107; Target polynomial: x^10+x^9+x^5+x^2+1, seed in first polarization direction: 0x26A, and seed in second polarization direction: 0x03A; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x379; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x3EF; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x2D1, and seed in second polarization direction: 0x379; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x2D1, and seed in second polarization direction: 0x3EF; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x1E2; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x170, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x0B8, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x299, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x354, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x17C, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x1AA, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x06A, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x3E6, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2A9, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2F9, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x0D5, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x1F3; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x14B; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x297; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x12F; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x3AC; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed for first polarization direction: 0x320, and seed for second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x3AC; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x3AC, and seed in second polarization direction: 0x01A; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1B0, and seed in second polarization direction: 0x3F4; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1B0, and seed in second polarization direction: 0x1FA; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x3F4, and seed in second polarization direction: 0x13D; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1FA, and seed in second polarization direction: 0x13D; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x35C, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x0DC, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x33A, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x26E, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x2B9; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x1B9; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x275; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x39D; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x173; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x39B; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x337; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed for first polarization direction: 0x0C6, and seed for second polarization direction: 0x157; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x0C6, and seed in second polarization direction: 0x2D7; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x263, and seed in second polarization direction: 0x157; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x263, and seed in second polarization direction: 0x2D7; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x130; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x298; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x34C; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x130, and seed in second polarization direction: 0x014; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x130, and seed in second polarization direction: 0x282; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x298, and seed in second polarization direction: 0x014; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x298, and seed in second polarization direction: 0x282; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x34C; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x34C, and seed in second polarization direction: 0x282; or Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed for first polarization direction: 0x282, and seed for second polarization direction: 0x261.

[0193] In some possible implementations, N=6144, M=64, Q=96, and the correspondence between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is one of the following: Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x1E1; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x094, and seed in second polarization direction: 0x02B; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x058, and seed in second polarization direction: 0x3CC; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x316; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x18E; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x163; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x152, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x2A4, and seed in second polarization direction: 0x316; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x0B4, and seed in second polarization direction: 0x2D1; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x05A; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x05A, and seed in second polarization direction: 0x2D1; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x128, and seed in second polarization direction: 0x12A; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x250, and seed in second polarization direction: 0x12A; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x250, and seed in second polarization direction: 0x295; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x39C, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x18E, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x36E, and seed in second polarization direction: 0x239; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x36E, and seed in second polarization direction: 0x0E7; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x232, and seed in second polarization direction: 0x36A; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x119; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed for first polarization direction: 0x282, and seed for second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x2A6, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x196, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x259; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x380, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x380, and seed in second polarization direction: 0x081; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x375; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x353; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x2FF; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x3FF; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x301, and seed in second polarization direction: 0x2D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x301, and seed in second polarization direction: 0x3D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x3D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x0AD; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x19C, and seed in second polarization direction: 0x301; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x186; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x1A3; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x346; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x1C5; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x063; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x1C5, and seed in second polarization direction: 0x327; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x240, and seed in second polarization direction: 0x3C4; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x103; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x226; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x165; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x165, and seed in second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed for first polarization direction: 0x266, and seed for second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x3E2; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x0C4, and seed in second polarization direction: 0x226; or Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, Seed in first polarization direction: 0x1D8, and Seed in second polarization direction: 0x2D9.

[0194] It should be understood that the above polynomials and seeds have good differential autocorrelation and cross-correlation properties, and can achieve good correlation effects even when there is a frequency difference between the transmitting laser and the receiving laser.

[0195] In some possible implementations, N=6144, M=64, Q=96, the target polynomial is x^9+x^4+x^3+x+1, the seed for the first polarization direction is 0x049, the seed for the second polarization direction is 0x115, and the first polarization direction and the second polarization direction are orthogonal to each other.

[0196] The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A+-Aj,-A+Aj,-A+Aj,-A+ Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A +Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj, and A+Aj.

[0197] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A-Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,- A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,A+Aj,- -A+Aj,A-Aj,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,and A+Aj.

[0198] In some possible implementations, N=6144, M=64, Q=96, the target polynomial expression is x^10+x^9+x^4+x+1, the sequence in the 1st bias direction is 0x12A, and the 2nd bias direction is 0x039.

[0199] The 96 pilot symbols in the 1st wave direction are as follows: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj,A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,- j,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, and -A+Aj.

[0200] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A- Aj,A+Aj,A-Aj,-A+Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A +Aj,-A-Aj,A+Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,-A+Aj, A-Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,-A-Aj,A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,A+Aj,A -Aj,A+Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A- Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,and A+Aj.

[0201] In some possible implementations, the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in multiple optical signals for transmission.

[0202] In some possible implementations, W data frames are carried by W optical signals, where any two of the W optical signals have different wavelengths. Alternatively, all W optical signals have the same wavelength, and each W optical signal is transmitted over W optical fibers.

[0203] In some possible implementations, the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other. In the first polarization direction, Q pilot symbols in the first data frame are generated using a first target polynomial and a first seed; and in the second polarization direction, Q pilot symbols in the first data frame are generated using the first target polynomial and a second seed. In the first polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a fourth seed.

[0204] In some possible implementations, the first pilot symbol sequence in the first data frame is the same as the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0205] In some possible implementations, the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

[0206] In some possible implementations, the first pilot symbol sequence in the first data frame is different from the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0207] In some possible implementations, the first target polynomial is the same as the second target polynomial, and any two of the first seed, second seed, third seed, and fourth seed are different from each other.

[0208] In some possible implementations, the first target polynomial is different from the second target polynomial.

[0209] In some possible implementations, the number of consecutive identical pilot symbols in a data frame in a given polarization direction is four or less.

[0210] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is 16QAM, with A=-1, 1, -3, 3, -√5, or √5.

[0211] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is QPSK, with A=-1 or 1.

[0212] According to a sixth aspect, an embodiment of the present application provides a data transmission device. The data transmission device includes a processing unit and a transmitting unit. The processing unit is configured to generate a data frame. In a certain polarization direction, the data frame includes N symbols, one pilot symbol at a certain fixed position for every M consecutive symbols among the N symbols, and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1. The Q pilot symbols are generated using a target polynomial and a seed, each pilot symbol being one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number. The Q pilot symbols are DC balanced, and the difference between any two of the numbers of -A-Aj, -A+Aj, A-Aj, and A+Aj in the data frame is less than or equal to 2. The transmitting unit is configured to transmit the data frame.

[0213] In implementation, the difference between any two of the numbers of pilot symbols in a data frame that are -A-Aj, -A+Aj, A-Aj, and A+Aj is less than or equal to 2. Furthermore, the number of pilot symbols that are -A-Aj is the same as the number of pilot symbols that are A+Aj, and the number of pilot symbols that are -A+Aj is the same as the number of pilot symbols that are A-Aj. This effectively ensures that the number of symbols in each polarization direction is approximately balanced, further ensuring that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0214] In implementation, the difference between any two of the numbers of pilot symbols in a data frame that are -A-Aj, -A+Aj, A-Aj, and A+Aj is less than or equal to 2. Furthermore, the number of pilot symbols that are -A-Aj is the same as the number of pilot symbols that are A+Aj, and the number of pilot symbols that are -A+Aj is the same as the number of pilot symbols that are A-Aj. This effectively ensures that the number of symbols in each polarization direction is approximately balanced, further ensuring that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0215] In some possible implementations, for a given polarization direction, in a data frame: The number of pilot symbols is -A-Aj.

[0216]

number

[0217]

number

[0218]

number

[0219]

number

[0220] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0221]

number

[0222]

number

[0223]

number

[0224]

number

[0225] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0226]

number

[0227]

number

[0228]

number

[0229]

number

[0230] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0231]

number

[0232]

number

[0233]

number

[0234]

number

[0235]

number

[0236] In some possible implementations, N=6144, M=64, Q=96, the target polynomial is x^9+x^8+x^5+x^4+1, the seed for the first polarization direction is 0x175, the seed for the second polarization direction is 0x03D, and the first polarization direction and the second polarization direction are orthogonal to each other.

[0237] In some possible implementations, the 96 pilot symbols in the first polarization direction are, in order: A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj ,A+Aj,-A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A+Aj,-A+Aj, -A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,-A-Aj,-A-A j,A-Aj,A+Aj,A-Aj,A+Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A+Aj,-A-A j,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,-A+ Aj,A-Aj,-A+Aj,A+Aj,A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A+Aj,A+A j,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,A-Aj,A+ Aj,-A+Aj,A-Aj,-A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,A-Aj,and -A-Aj.

[0238] The 96 pilot symbols in the second polarization direction are, in order: A-Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj, -A-Aj,-A+Aj,A-Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,A -Aj,-A+Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj, -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A-Aj,A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A-Aj,A+Aj, and A+Aj.

[0239] In some possible implementations, in the 1st wave direction, in the data frame, -A-Also the number of pilot symbols

[0240]

number

[0241]

number

[0242]

number

[0243]

number

[0244]

number

[0245]

number

[0246]

number

[0247]

number

[0248] Alternatively, in the first polarization direction, in the data frame, The number of pilot symbols is -A-Aj.

[0249]

number

[0250]

number

[0251]

number

[0252]

number

[0253]

number

[0254]

number

[0255]

number

[0256]

number

[0257]

number

[0258] In implementation, in the two polarization directions, the total number of pilot symbols for -A-Aj is Q / 2, the total number of pilot symbols for -A+Aj is Q / 2, the total number of pilot symbols for A-Aj is Q / 2, and the total number of pilot symbols for A+Aj is Q / 2. This effectively ensures a balance between the symbol quantities, and further ensures that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0259] In some possible implementations, N=6144, M=64, Q=96, and the first and second polarization directions are orthogonal to each other.

[0260] The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A+-Aj,-A+Aj,-A+Aj,-A+ Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A +Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj, and A+Aj.

[0261] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A-Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,- A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,A+Aj,- -A+Aj,A-Aj,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,and A+Aj.

[0262] In some possible implementations, N=6144, M=64, Q=96, and the 1st wave direction and the 2nd wave direction are in direct contact with each other.

[0263] The 96 pilot symbols in the 1st wave direction are as follows: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj,A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,- j,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, and -A+Aj.

[0264] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A- Aj,A+Aj,A-Aj,-A+Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A +Aj,-A-Aj,A+Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,-A+Aj, A-Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,-A-Aj,A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,A+Aj,A -Aj,A+Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A- Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,and A+Aj.

[0265] In some possible implementations, the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in multiple optical signals for transmission.

[0266] In some possible implementations, W data frames are carried by W optical signals, where any two of the W optical signals have different wavelengths. Alternatively, all W optical signals have the same wavelength, and each W optical signal is transmitted over W optical fibers.

[0267] In some possible implementations, the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other. In the first polarization direction, Q pilot symbols in the first data frame are generated using a first target polynomial and a first seed; and in the second polarization direction, Q pilot symbols in the first data frame are generated using the first target polynomial and a second seed. In the first polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a fourth seed.

[0268] In some possible implementations, the first pilot symbol sequence in the first data frame is the same as the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0269] In some possible implementations, the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

[0270] In some possible implementations, the first pilot symbol sequence in the first data frame is different from the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0271] In some possible implementations, the first target polynomial is the same as the second target polynomial, and any two of the first seed, second seed, third seed, and fourth seed are different from each other.

[0272] In some possible implementations, the first target polynomial is different from the second target polynomial.

[0273] In some possible implementations, the number of consecutive identical pilot symbols in a data frame in a given polarization direction is four or less.

[0274] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is 16QAM, with A=-1, 1, -3, 3, -√5, or √5.

[0275] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is QPSK, with A=-1 or 1.

[0276] According to a seventh aspect, an embodiment of the present application provides a data transmission device. The data transmission device includes a receiving unit and a processing unit. The receiving unit is configured to receive a data frame. In a certain polarization direction, the data frame includes N symbols, one pilot symbol at a certain fixed position for every M consecutive symbols among the N symbols, and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1. The Q pilot symbols are generated using a target polynomial and a seed, each pilot symbol being one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number. The Q pilot symbols are DC-balanced, the degree of the target polynomial is less than or equal to 10, and the number of terms of the target polynomial is greater than or equal to 2 and less than or equal to 8. The processing unit is configured to process the data frame.

[0277] In this implementation, in a data frame containing N symbols, every M consecutive symbols contain a pilot symbol at a fixed position and M-1 payload symbols, where N=M×Q. The Q pilot symbols in the data frame are generated using a target polynomial and a seed, where the Q pilot symbols are DC-balanced, the degree of the target polynomial is 10 or less, and the number of terms in the target polynomial is between 2 and 8. It can be seen that a simple target polynomial is designed in this application to generate the pilot symbols. Correspondingly, a simple hardware structure can be used for implementation. Furthermore, the pilot symbols generated by the above method have good autocorrelation and cross-correlation properties and are DC-balanced, which helps the receiver restore signal quality.

[0278] In some possible implementations, the target polynomial is one of the following: x^9+x^4+x^3+x+1; x^9+x^5+x^4+x+1; x^9+x^8+x^5+x^4+1; x^9+x^8+x^6+x^5+1; x^10+x^4+x^3+x+1; x^10+x^5+x^2+x+1; x^10+x^8+x^5+x+1; x^10+x^9+x^4+x+1; x^10+x^9+x^5+x^2+1; x^10+x^9+x^6+x+1; x^10+x^9+x^7+x^6+1; x^10+x^9+x^8+x^5+1; x^10+x^8+x^6+x^5+x^3+x+1; x^10+x^8+x^7+x^3+x^2+x+1; x^10+x^8+x^7+x^6+x^2+x+1; x^10+x^9+x^7+x^5+x^4+x^2+1; x^10+x^9+x^8+x^4+x^3+x^2+1; or x^10+x^9+x^8+x^7+x^3+x^2+1.

[0279] In some possible implementations, the target polynomial is one of the following: x^10+x^9+x^8+x^7+x^4+x+1; or x^10+x^9+x^6+x^3+x^2+x+1.

[0280] It should be understood that the above polynomials have good differential autocorrelation and cross-correlation properties, and can achieve good correlation effect even when there is a frequency difference between the transmitting laser and the receiving laser.

[0281] In some possible implementations, each pilot symbol is located at the beginning of M consecutive symbols in which the pilot symbols are located.

[0282] In some possible implementations, the sequence containing Q pilot symbols in the first polarization direction is different from the sequence containing Q pilot symbols in the second polarization direction, and the first polarization direction and the second polarization direction are orthogonal to each other, which avoids the problem that the receiver cannot distinguish between the two polarization directions in actual transmission.

[0283] In some possible implementations, N=6144, M=64, Q=96, and the correspondence between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is one of the following: Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x002, and seed in second polarization direction: 0x115; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x002, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x049, and seed in second polarization direction: 0x115; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x049, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x115, and seed in second polarization direction: 0x08D; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x08D, and seed in second polarization direction: 0x02B; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x098, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x14C, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x0FE; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x0BF; Target polynomial: x^9+x^5+x^4+x+1, seed in first polarization direction: 0x0A6, and seed in second polarization direction: 0x17F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x11E; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x11E; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x0EA, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x11E, and seed in second polarization direction: 0x175; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x175, and seed in second polarization direction: 0x03D; Target polynomial: x^9+x^8+x^5+x^4+1, seed in first polarization direction: 0x175, and seed in second polarization direction: 0x08F; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x16A, and seed in second polarization direction: 0x1E1; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x16A, and seed in second polarization direction: 0x1C3; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1E1, and seed in second polarization direction: 0x069; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1E1, and seed in second polarization direction: 0x113; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x069, and seed in second polarization direction: 0x1C3; Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1C3, and seed in second polarization direction: 0x113; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x0E6, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x3DC, and seed in second polarization direction: 0x36A; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x35E; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x1AF; Target polynomial: x^10+x^8+x^5+x+1, seed in first polarization direction: 0x1FD, and seed in second polarization direction: 0x3A7; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x12A, and seed in second polarization direction: 0x039; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x12A, and seed in second polarization direction: 0x107; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x039, and seed in second polarization direction: 0x295; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x295, and seed in second polarization direction: 0x107; Target polynomial: x^10+x^9+x^5+x^2+1, seed in first polarization direction: 0x26A, and seed in second polarization direction: 0x03A; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x379; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x3EF; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x2D1, and seed in second polarization direction: 0x379; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x2D1, and seed in second polarization direction: 0x3EF; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x1E2; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x170, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x0B8, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x299, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x354, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x17C, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x1AA, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x06A, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x3E6, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2A9, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2F9, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x0D5, and seed in second polarization direction: 0x2AD; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x1F3; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x14B; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x297; Target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, seed in first polarization direction: 0x2AD, and seed in second polarization direction: 0x12F; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x3AC; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed for first polarization direction: 0x320, and seed for second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x320, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x3AC; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x3AC, and seed in second polarization direction: 0x01A; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x1D6; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x075; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1B0, and seed in second polarization direction: 0x3F4; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1B0, and seed in second polarization direction: 0x1FA; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x3F4, and seed in second polarization direction: 0x13D; Target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, seed in first polarization direction: 0x1FA, and seed in second polarization direction: 0x13D; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x35C, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x0DC, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x33A, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x26E, and seed in second polarization direction: 0x2EE; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x2B9; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x1B9; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x275; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x39D; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x173; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed in first polarization direction: 0x2EE, and seed in second polarization direction: 0x0EB; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x39B; Target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, seed for first polarization direction: 0x2EE, and seed for second polarization direction: 0x337; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed for first polarization direction: 0x0C6, and seed for second polarization direction: 0x157; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x0C6, and seed in second polarization direction: 0x2D7; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x263, and seed in second polarization direction: 0x157; Target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, seed in first polarization direction: 0x263, and seed in second polarization direction: 0x2D7; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x130; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x298; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x34C; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x350, and seed in second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x130, and seed in second polarization direction: 0x014; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x130, and seed in second polarization direction: 0x282; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x298, and seed in second polarization direction: 0x014; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x298, and seed in second polarization direction: 0x282; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x34C; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x34C, and seed in second polarization direction: 0x282; or Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed for first polarization direction: 0x282, and seed for second polarization direction: 0x261.

[0284] In some possible implementations, N=6144, M=64, Q=96, and the correspondence between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is one of the following: Target polynomial: x^9+x^8+x^6+x^5+1, seed in first polarization direction: 0x1D4, and seed in second polarization direction: 0x1E1; Target polynomial: x^9+x^4+x^3+x+1, seed in first polarization direction: 0x094, and seed in second polarization direction: 0x02B; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x058, and seed in second polarization direction: 0x3CC; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x316; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x18E; Target polynomial: x^10+x^9+x^7+x^6+1, seed in first polarization direction: 0x3CC, and seed in second polarization direction: 0x163; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x152, and seed in second polarization direction: 0x14D; Target polynomial: x^10+x^9+x^8+x^5+1, seed in first polarization direction: 0x2A4, and seed in second polarization direction: 0x316; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x0B4, and seed in second polarization direction: 0x2D1; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x1A2, and seed in second polarization direction: 0x05A; Target polynomial: x^10+x^9+x^6+x+1, seed in first polarization direction: 0x05A, and seed in second polarization direction: 0x2D1; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x128, and seed in second polarization direction: 0x12A; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x250, and seed in second polarization direction: 0x12A; Target polynomial: x^10+x^9+x^4+x+1, seed in first polarization direction: 0x250, and seed in second polarization direction: 0x295; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x39C, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x18E, and seed in second polarization direction: 0x36E; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x36E, and seed in second polarization direction: 0x239; Target polynomial: x^10+x^4+x^3+x+1, seed in first polarization direction: 0x36E, and seed in second polarization direction: 0x0E7; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x232, and seed in second polarization direction: 0x36A; Target polynomial: x^10+x^5+x^2+x+1, seed in first polarization direction: 0x36A, and seed in second polarization direction: 0x119; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed for first polarization direction: 0x282, and seed for second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, seed in first polarization direction: 0x014, and seed in second polarization direction: 0x01F; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x2A6, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x196, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x259; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x380, and seed in second polarization direction: 0x2CE; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x380, and seed in second polarization direction: 0x081; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x375; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x353; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x2FF; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed for first polarization direction: 0x2CE, and seed for second polarization direction: 0x3FF; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x301, and seed in second polarization direction: 0x2D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x301, and seed in second polarization direction: 0x3D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x3D9; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x1BA, and seed in second polarization direction: 0x0AD; Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, seed in first polarization direction: 0x19C, and seed in second polarization direction: 0x301; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x0D4, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, seed in first polarization direction: 0x01A, and seed in second polarization direction: 0x0ED; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x186; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x261; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x1A3; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x346; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x1C5; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x063; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x1C5, and seed in second polarization direction: 0x327; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x240, and seed in second polarization direction: 0x3C4; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x3C4, and seed in second polarization direction: 0x103; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x226; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x165; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x165, and seed in second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed for first polarization direction: 0x266, and seed for second polarization direction: 0x0C7; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x2E2, and seed in second polarization direction: 0x3E2; Target polynomial: x^10+x^9+x^6+x^3+x^2+x+1, seed in first polarization direction: 0x0C4, and seed in second polarization direction: 0x226; or Target polynomial: x^10+x^9+x^8+x^7+x^4+x+1, Seed in first polarization direction: 0x1D8, and Seed in second polarization direction: 0x2D9.

[0285] It should be understood that the above polynomials and seeds have good differential autocorrelation and cross-correlation properties, and can achieve good correlation effects even when there is a frequency difference between the transmitting laser and the receiving laser.

[0286] In some possible implementations, N=6144, M=64, Q=96, the target polynomial is x^9+x^4+x^3+x+1, the seed for the first polarization direction is 0x049, the seed for the second polarization direction is 0x115, and the first polarization direction and the second polarization direction are orthogonal to each other.

[0287] The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A+-Aj,-A+Aj,-A+Aj,-A+ Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A +Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj, and A+Aj.

[0288] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A-Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,- A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,A+Aj,- -A+Aj,A-Aj,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj, and A+Aj.

[0289] In some possible implementations, N=6144, M=64, Q=96, the target polynomial expression is x^10+x^9+x^4+x+1, the sequence in the 1st bias direction is 0x12A, and the 2nd bias direction is 0x039.

[0290] The 96 pilot symbols in the 1st wave direction are as follows: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj,A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,- j,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, and -A+Aj.

[0291] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A- Aj,A+Aj,A-Aj,-A+Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A +Aj,-A-Aj,A+Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,-A+Aj, A-Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,-A-Aj,A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,A+Aj,A -Aj,A+Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A- Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,and A+Aj.

[0292] In some possible implementations, the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in multiple optical signals for transmission.

[0293] In some possible implementations, W data frames are carried by W optical signals, where any two of the W optical signals have different wavelengths. Alternatively, all W optical signals have the same wavelength, and each W optical signal is transmitted over W optical fibers.

[0294] In some possible implementations, the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other. In the first polarization direction, Q pilot symbols in the first data frame are generated using a first target polynomial and a first seed; and in the second polarization direction, Q pilot symbols in the first data frame are generated using the first target polynomial and a second seed. In the first polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a fourth seed.

[0295] In some possible implementations, the first pilot symbol sequence in the first data frame is the same as the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0296] In some possible implementations, the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

[0297] In some possible implementations, the first pilot symbol sequence in the first data frame is different from the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0298] In some possible implementations, the first target polynomial is the same as the second target polynomial, and any two of the first seed, second seed, third seed, and fourth seed are different from each other.

[0299] In some possible implementations, the first target polynomial is different from the second target polynomial.

[0300] In some possible implementations, the number of consecutive identical pilot symbols in a data frame in a given polarization direction is four or less.

[0301] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is 16QAM, with A=-1, 1, -3, 3, -√5, or √5.

[0302] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is QPSK, with A=-1 or 1.

[0303] According to an eighth aspect, an embodiment of the present application provides a data transmission device. The data transmission device includes a receiving unit and a processing unit. The receiving unit is configured to receive a data frame. In a certain polarization direction, the data frame includes N symbols, one pilot symbol at a certain fixed position for every M consecutive symbols among the N symbols, and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1. The Q pilot symbols are generated using a target polynomial and a seed, each pilot symbol being one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number. The Q pilot symbols are DC-balanced, and the difference between any two of the numbers of -A-Aj, -A+Aj, A-Aj, and A+Aj in the data frame is less than or equal to 2. The processing unit is configured to process the data frame.

[0304] In implementation, the difference between any two of the numbers of pilot symbols in a data frame that are -A-Aj, -A+Aj, A-Aj, and A+Aj is less than or equal to 2. Furthermore, the number of pilot symbols that are -A-Aj is the same as the number of pilot symbols that are A+Aj, and the number of pilot symbols that are -A+Aj is the same as the number of pilot symbols that are A-Aj. This effectively ensures that the number of symbols in each polarization direction is approximately balanced, further ensuring that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0305] In some possible implementations, for a given polarization direction, in a data frame: The number of pilot symbols is -A-Aj.

[0306]

number

[0307]

number

[0308]

number

[0309]

number

[0310] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0311]

number

[0312]

number

[0313]

number

[0314]

number

[0315] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0316]

number

[0317]

number

[0318]

number

[0319]

number

[0320] Alternatively, in a given polarization direction, in a data frame, The number of pilot symbols is -A-Aj.

[0321]

number

[0322]

number

[0323]

number

[0324]

number

[0325]

number

[0326] In some possible implementations, N=6144, M=64, Q=96, the target polynomial is x^9+x^8+x^5+x^4+1, the seed for the first polarization direction is 0x175, the seed for the second polarization direction is 0x03D, and the first polarization direction and the second polarization direction are orthogonal to each other.

[0327] In some possible implementations, the 96 pilot symbols in the first polarization direction are, in order: A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,-A+A-Aj,A-Aj,A-Aj,A-Aj,-A+Aj, -A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj j,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj j,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj, and -A-Aj.

[0328] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj, -A-Aj,-A+Aj,A-Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,A -Aj,-A+Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj, -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A-Aj,A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A-Aj,A+Aj, and A+Aj.

[0329] In some possible implementations, in the 1st wave direction, in the data frame, -A-Also the number of pilot symbols

[0330]

number

[0331]

number

[0332]

number

[0333]

number

[0334]

number

[0335]

number

[0336]

number

[0337]

number

[0338] Alternatively, in the first polarization direction, in the data frame, The number of pilot symbols is -A-Aj.

[0339]

number

[0340]

number

[0341]

number

[0342]

number

[0343]

number

[0344]

number

[0345]

number

[0346]

number

[0347]

number

[0348] In implementation, in the two polarization directions, the total number of pilot symbols for -A-Aj is Q / 2, the total number of pilot symbols for -A+Aj is Q / 2, the total number of pilot symbols for A-Aj is Q / 2, and the total number of pilot symbols for A+Aj is Q / 2. This effectively ensures a balance between the symbol quantities, and further ensures that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0349] In some possible implementations, N=6144, M=64, Q=96, and the first and second polarization directions are orthogonal to each other.

[0350] The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A+-Aj,-A+Aj,-A+Aj,-A+ Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A +Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj, and A+Aj.

[0351] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,A-Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,- A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,A+Aj,- -A+Aj,A-Aj,A+Aj,-A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,and A+Aj.

[0352] In some possible implementations, N=6144, M=64, Q=96, and the 1st wave direction and the 2nd wave direction are in direct contact with each other.

[0353] The 96 pilot symbols in the 1st wave direction are as follows: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj,A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,-A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,- j,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj, and -A+Aj.

[0354] The 96 pilot symbols in the 2nd wave direction are as follows: A-Aj,-A+Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A+Aj,A-Aj,-A-Aj,A+Aj,-A- Aj,A+Aj,A-Aj,-A+Aj,-A-Aj,A-Aj,-A+Aj,-A-Aj,-A+Aj,A+Aj,-A-Aj,A+Aj,-A +Aj,-A-Aj,A+Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,-A+Aj, A-Aj,A+Aj,-A+Aj,A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,A-Aj,A-Aj,-A+Aj,-A-Aj,A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,-A+Aj,A-Aj,A-Aj,A-Aj,-A+Aj,A+Aj,A -Aj,A+Aj,A-Aj,-A-Aj,A-Aj,-A+Aj,A+Aj,A+Aj,A+Aj,A-Aj,-A+Aj,-A+Aj,-A- Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,A+Aj,A-Aj,A+Aj,and A+Aj.

[0355] In some possible implementations, the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in multiple optical signals for transmission.

[0356] In some possible implementations, W data frames are carried by W optical signals, where any two of the W optical signals have different wavelengths. Alternatively, all W optical signals have the same wavelength, and each W optical signal is transmitted over W optical fibers.

[0357] In some possible implementations, the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other. In the first polarization direction, Q pilot symbols in the first data frame are generated using a first target polynomial and a first seed; and in the second polarization direction, Q pilot symbols in the first data frame are generated using the first target polynomial and a second seed. In the first polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated using a second target polynomial and a fourth seed.

[0358] In some possible implementations, the first pilot symbol sequence in the first data frame is the same as the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0359] In some possible implementations, the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

[0360] In some possible implementations, the first pilot symbol sequence in the first data frame is different from the second pilot symbol sequence in the second data frame, the first pilot symbol sequence includes Q pilot symbols in the first data frame, and the second pilot symbol sequence includes Q pilot symbols in the second data frame.

[0361] In some possible implementations, the first target polynomial is the same as the second target polynomial, and any two of the first seed, second seed, third seed, and fourth seed are different from each other.

[0362] In some possible implementations, the first target polynomial is different from the second target polynomial.

[0363] In some possible implementations, the number of consecutive identical pilot symbols in a data frame in a given polarization direction is four or less.

[0364] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is 16QAM, with A=-1, 1, -3, 3, -√5, or √5.

[0365] In some possible implementations, in a given polarization direction, the modulation format of the symbols in the data frame is QPSK, with A=-1 or 1.

[0366] In the implementation of the present application, in a data frame containing N symbols, every M consecutive symbols contain a pilot symbol at a fixed position and M-1 payload symbols, where N=M×Q. The Q pilot symbols in the data frame are generated using a target polynomial and a seed, where the Q pilot symbols are DC-balanced, the degree of the target polynomial is 10 or less, and the number of terms of the target polynomial is between 2 and 8. It can be seen that a simple target polynomial is designed in the present application to generate the pilot symbols. Correspondingly, a simple hardware structure can be used for implementation. Furthermore, the pilot symbols generated by the above method have good autocorrelation and cross-correlation properties and are DC-balanced, which helps the receiver restore signal quality. [Brief explanation of the drawings]

[0367] [Figure 1] FIG. 1 is a diagram of a communication system to which an embodiment of the present application is applied. [Figure 2] FIG. 2 is a diagram of an implementation of a transmitting DSP processor according to an embodiment of the present application. [Figure 3] FIG. 3 is a diagram of another implementation of a transmitting DSP processor according to an embodiment of the present application. [Figure 4] FIG. 4 is a schematic flowchart of a data transmission method according to an embodiment of the present application. [Figure 5] FIG. 5 is a diagram of a data frame structure according to an embodiment of the present application. [Figure 6] FIG. 6 is an illustration of symbols in a constellation diagram according to an embodiment of the present application. [Figure 7] FIG. 7 is a diagram of a first generation structure of pilot symbols according to an embodiment of the present application. [Figure 8] FIG. 8 is a diagram of a second generation structure of pilot symbols according to an embodiment of the present application. [Figure 9]FIG. 9 is a diagram of another data frame structure according to an embodiment of the present application. [Figure 10] FIG. 10 is a diagram of a third generation structure of pilot symbols according to an embodiment of the present application. [Figure 11] FIG. 11 is a diagram of a first implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. [Figure 12(a)] 12(a) through 12(c) are diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 12(b)] 12(a) through 12(c) are diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 12(c)] 12(a) through 12(c) are diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 13(a)] 13(a) and 13(b) are diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 13(b)] 13(a) and 13(b) are diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 14] FIG. 14 is a diagram of a fourth generation structure of pilot symbols according to an embodiment of the present application. [Figure 15] FIG. 15 is a diagram of a second implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. [Figure 16(a)] 16(a) to 16(c) are other diagrams of correlation characteristics corresponding to pilot symbols according to embodiments of the present application. [Figure 16(b)] 16(a) to 16(c) are other diagrams of correlation characteristics corresponding to pilot symbols according to embodiments of the present application. [Figure 16(c)] 16(a) to 16(c) are other diagrams of correlation characteristics corresponding to pilot symbols according to embodiments of the present application. [Figure 17(a)] 17(a) and 17(b) are other diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 17(b)] 17(a) and 17(b) are other diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 18] FIG. 18 is a diagram of a transmission scene of multiple data frame streams according to an embodiment of the present application. [Figure 19] FIG. 19 is a diagram of a fifth generation structure of pilot symbols according to an embodiment of the present application. [Figure 20] FIG. 20 is a diagram of a third implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. [Figure 21(a)] 21(a) to 21(c) are other diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 21(b)] 21(a) to 21(c) are other diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 21(c)] 21(a) to 21(c) are other diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 22(a)] 22(a) and 22(b) are other diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 22(b)] 22(a) and 22(b) are other diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 23] FIG. 23 is a diagram of a sixth generation structure of pilot symbols according to an embodiment of the present application. [Figure 24] FIG. 24 is a diagram of a fourth implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. [Figure 25(a)]25(a) and 25(b) are other diagrams of autocorrelation and cross-correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 25(b)] 25(a) and 25(b) are other diagrams of autocorrelation and cross-correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 26(a)] 26(a) and 26(b) are diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 26(b)] 26(a) and 26(b) are diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 27] FIG. 27 is a diagram of a seventh generation structure of pilot symbols according to an embodiment of the present application. [Figure 28] FIG. 28 is a diagram of a fifth implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. [Figure 29(a)] 29(a) and 29(b) are other diagrams of autocorrelation and cross-correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 29(b)] 29(a) and 29(b) are other diagrams of autocorrelation and cross-correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. [Figure 30(a)] 30(a) and 30(b) are other diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 30(b)] 30(a) and 30(b) are other diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application. [Figure 31] FIG. 31 is a structural diagram of a data transmission device used at the transmitting side according to an embodiment of the present application. [Figure 32] FIG. 32 is a diagram of the structure of a data transmission device used at the receiving end according to an embodiment of the present application. [Figure 33]FIG. 33 is a diagram of another structure of a data transmission device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0368] The embodiments of the present application provide a data transmission method and a data transmission device. A simple target polynomial is designed to generate pilot symbols. Correspondingly, a simple hardware structure can be used for implementation. Furthermore, the generated pilot symbols have good autocorrelation and cross-correlation characteristics and maintain DC balance, which helps the receiving side restore signal quality.

[0369] It should be noted that in the specification, claims, and aforementioned accompanying drawings of this application, the terms "first," "second," and similar terms are intended to distinguish between similar objects, but are not intended to limit a particular order or sequence. It should be understood that the foregoing terms may be interchanged where appropriate, such that the embodiments described herein may be performed in orders other than those described herein. Furthermore, the terms "comprise," "have," and any other variations thereof are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those explicitly listed steps or units and may include other steps or units that are not explicitly listed or that are inherent to the process, method, product, or device.

[0370] FIG. 1 is a diagram of a communication system to which an embodiment of the present application is applied. As shown in FIG. 1, at the transmitting side, a source provides a data stream to be transmitted. An encoder receives and encodes the data stream. The encoded codeword information, which combines parity bits and information bits, is sent to a transmitting side digital signal processing (DSP) processor for framing and transmitted to a receiving side through a channel. After receiving a signal with distortion resulting from noise or other impairments in the channel, the receiving side sends the signal to the receiving side DSP processor for dispersion compensation, synchronization, phase recovery, and other processing. A decoder then performs decoding to restore the original data and sends the data to a sink.

[0371] FIG. 2 is a diagram illustrating an implementation of a transmitting DSP processor according to an embodiment of the present application. As shown in FIG. 2, in a possible implementation, the transmitting DSP processor performs symbol mapping on a received data sequence. Typically, the received data sequence is an information sequence and a parity sequence obtained based on a forward error correction (FEC) code. Symbol mapping methods include, but are not limited to, quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM). The transmitting DSP processor further performs polarization symbol distribution on the data sequence to obtain dual-polarization (DP) symbols, such as DP-QPSK, DP-8QAM, DP-16QAM, DP-32QAM, or DP-64QAM symbols. For ease of explanation, in the following, the two polarization directions are collectively referred to as the X polarization direction and the Y polarization direction, where the X polarization direction and the Y polarization direction are orthogonal to each other. It should be understood that the X polarization direction and the Y polarization direction are not two specified polarization directions, but any two polarization directions that are orthogonal to each other.

[0372] Furthermore, the transmitting DSP processor performs the following framing process for a certain number of dual-polarized symbols: pilot symbols are inserted in each of the X and Y polarization directions to obtain a sequence of dual-polarized symbols to be transmitted, called a frame. In the embodiment, the frame is called a data frame, and may also be called a DSP frame.

[0373] It should be noted that after symbol mapping, the symbols may be further interleaved, and the framing process described above is performed on the interleaved symbols. It should be understood that one dual-polarization symbol can be represented by two symbols, one located in the X polarization direction and the other located in the Y polarization direction. Each symbol can be represented by a complex number. For example, a symbol obtained by 16QAM modulation can be represented by one of the following 16 complex numbers: ±1±1j, ±1±3j, ±3±1j, and ±3±3j, where ± represents a positive or negative value. For example, ±3 represents 3 or -3. j represents the imaginary unit. In some scenarios, the imaginary unit may alternatively be represented by another symbol, such as i. This is not a limitation of the present invention. In some cases, the real and imaginary parts are normalized, but the essence remains the same. Furthermore, a sequence with L dual-polarized symbols can be completely represented by two complex sequences of length L, where one complex sequence represents the symbols in the X polarization direction and the other complex sequence represents the symbols in the Y polarization direction. Each complex sequence of length L is represented by a real part sequence (also called the I-channel sequence) of length L and an imaginary part sequence (also called the Q-channel sequence) of length L, where L is an integer greater than 1. Therefore, there are four different types of sequences, including X-polarized I-channel sequence, X-polarized Q-channel sequence, Y-polarized I-channel sequence, and Y-polarized Q-channel sequence.

[0374] 3 is a diagram of another implementation of a transmitting DSP processor according to an embodiment of the present application. As shown in FIG. 3, unlike the framing operation performed on the symbols shown in FIG. 2, in another possible implementation, before symbol mapping, the transmitting DSP processor can insert bits corresponding to pilot symbols into the received data sequence according to the symbol mapping rule used, and then obtain the same frame as in the processing shown in FIG. 2 through symbol mapping and polarization symbol distribution. In this case, the bit sequence obtained by inserting bits corresponding to the symbols before symbol mapping may be further interleaved, and then the same frame as in the processing shown in FIG. 2 is obtained through symbol mapping and polarization symbol distribution.

[0375] It should be noted that the specific framing scheme used by the transmitting DSP processor is not limited in this application. In addition to the framing schemes described in Figures 2 and 3, other similar framing methods are also applicable to the present solution and will not be described here.

[0376] 4 is a schematic flowchart of a data transmission method according to an embodiment of the present application. It should be understood that the data transmission method is applied to the transmitting side and may be specifically implemented, for example, by the transmitting side DSP processor shown in FIG.

[0377] 401: Create a data frame.

[0378] It should be noted that the specific implementation of generating a data frame is not limited in the present application. For example, the framing schemes illustrated in FIG. 2 or FIG. 3 may be used. Of course, other similar framing schemes are also applicable to the present solution and will not be described here. It should be understood that a data frame includes symbols in two polarization directions, and the structure of the data frame in the two polarization directions is similar. For example, a data frame includes N symbols in the X polarization direction and N symbols in the Y polarization direction. The structure of the data frame will be described below by using one of the polarization directions as an example.

[0379] 5 is a diagram of a data frame structure according to an embodiment of the present application. As shown in FIG. 5, in a certain polarization direction, a data frame includes N symbols, and every M consecutive symbols in the N symbols include one pilot symbol at a fixed position and M-1 payload symbols, where N=M×Q, Q is an even number, and M is an integer equal to or greater than 1. In other words, every M consecutive symbols in the N symbols may be considered as one group, and the N symbols include a total of Q symbol groups. For example, N=6144, M=64, and Q=96. Symbol 1 through Symbol 64 are the 64 consecutive symbols in the first group, Symbols 65 through 128 are 64 consecutive symbols in the second group,... Symbols 6081 through 6144 are 64 consecutive symbols in the 96th group. Payload symbols, sometimes called pre-framing symbols, should be understood to include parity symbols and information symbols obtained through FEC coding. At the receiving end, pilot symbols may be used to aid in carrier phase recovery and may also be used to distinguish between the two polarization directions.

[0380] It should be understood that the specific location of the pilot symbols in each group of M symbols is not limited by this application. In one example, each pilot symbol is located at the beginning of M consecutive symbols in which the pilot symbol is located. For example, the first symbol in the data frame shown in Figure 5 is the first pilot symbol.

[0381] It should be noted that the Q pilot symbols in the data frame are generated by using a target polynomial and a seed. Each pilot symbol is one of -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number. The degree of the target polynomial is less than or equal to 10, and the number of terms in the target polynomial is between 2 and 8, resulting in low hardware implementation complexity. Furthermore, the Q pilot symbols maintain direct current balance, i.e., the sum of the Q pilot symbols is zero. Specifically, the sum of the real and imaginary parts of the complex numbers corresponding to the Q pilot symbols is both zero, thereby achieving direct current balance. This helps the receiver restore signal quality.

[0382] 402: Send a data frame.

[0383] The transmitted data frame is transmitted to the receiving end via a channel. The specific operations performed after the receiving end receives the data frame are not described in detail in this application. For details, please refer to the system structure diagram shown in Figure 1.

[0384] The characteristics of the pilot symbols and a specific method for generating the pilot symbols will be described in detail below.

[0385] In an embodiment of the present application, the value of A is determined based on the modulation format used during symbol generation. In some practical application scenarios, -A-Aj, -A+Aj, A-Aj, and A+Aj are symbols in the constellation diagram of the modulation format used. For example, if QPSK is used, there are only four symbols. In this case, A=±1, and each pilot symbol can be represented by one of -1-1j, -1+1j, 1-1j, and 1+1j. In one frame, there are all frame symbols represented by four complex numbers. If 16QAM is used, there are 16 symbols in the constellation diagram. In this case, A=±1 or ±3.

[0386] FIG. 6 is a diagram of symbols in a constellation diagram according to an embodiment of the present application. As shown in FIG. 6, when A=3 or -3, each pilot symbol can be represented by one of -3-3j, -3+3j, 3-3j, and 3+3j, for example, the hollow symbol shown in FIG. 6. Similarly, when 64QAM is used, A=±1, ±3, ±5, or ±7. It should be noted that a higher-order modulation format may alternatively be used. Details are not described in this application. In the actual transmission process, the four outer symbols of the constellation diagram are used as pilot symbols, resulting in a low symbol error probability.

[0387] It should be noted that the symbols in the constellation diagram may alternatively be compressed, and the values ​​of A will be compressed accordingly. 16QAM is used as an example, and power normalization is performed on the 16 symbols in the 16QAM constellation diagram. In this case, the values ​​of the 16 symbols in the 16QAM configuration diagram are

[0388]

number

[0389]

number

[0390] Alternatively, another form of normalization may be used, which is not a limitation of this application.

[0391] It should be understood that if the four outermost symbols in the constellation diagram are used as pilot symbols -A-Aj, -A+Aj, A-Aj, and A+Aj, the pilot symbols have high sensitivity but a large peak to average power ratio. If the four innermost symbols in the constellation diagram are used as pilot symbols -A-Aj, -A+Aj, A-Aj, and A+Aj, the pilot symbols have high sensitivity but a large peak to average power ratio. ·symbol has low noise but low sensitivity.

[0392] It should be noted that in some practical application scenarios, the pilot symbols -A-Aj, -A+Aj, A-Aj, and A+Aj may alternatively not be symbols in the constellation diagram of the modulation format used, but may be four symbols in the intermediate region between the four outermost and four innermost symbols in the constellation diagram. In this case, the pilot symbols have considerable noise and sensitivity, but a low peak-to-average power ratio. Using 16QAM as an example, the values ​​of the 16 symbols in the 16QAM constellation diagram are {±1±1j, ±1±3j, ±3±1j, ±3±3j}, and the value of the real number A satisfies 1≦A≦3. For example, the real number A=√5.

[0393] The two polarization directions are orthogonal to each other. Specifically, when one of the polarization directions is X polarization, the other polarization direction is Y polarization; or when one of the polarization directions is Y polarization, the other polarization direction is X polarization.

[0394] In a data frame, a sequence containing Q pilot symbols in the X polarization direction is different from a sequence containing Q pilot symbols in the Y polarization direction. For example, if the sequence containing pilot symbols in the X polarization direction is -A-Aj, -A-Aj, A+Aj, and A-Aj, in that order, the sequence containing pilot symbols in the Y polarization direction cannot be the same as the sequence containing pilot symbols in the X polarization direction, which may be -A-Aj, -A-Aj, A+Aj, and A+Aj. There is only one different symbol. This avoids the problem that the receiver cannot distinguish between the two polarization directions in actual transmission.

[0395] In an embodiment of the present application, when a 10th order polynomial is used as the target polynomial, the 10th order polynomial is:

[0396]

number

[0397] FIG. 7 is a diagram of a first generation structure of pilot symbols according to an embodiment of the present application. As shown in FIG. 7, each block may be regarded as one storage element, and the number of storage elements is the same as the number of bits in the preloaded seed, i.e., each storage element is configured to input a corresponding bit in the seed. For example, if the seed length is 10 bits, the seed may be expressed in binary format as m9, m8, m7, m6, m5, m4, m3, m2, m1, and m0, and 10 corresponding storage elements are used. Of course, the seed may alternatively be expressed in hexadecimal or decimal format and needs to be converted to binary format during operation with the target polynomial. For example, 0110111000 is expressed as 0x1B8 in hexadecimal format and 440 in decimal format.

[0398]

number

[0399] The polynomial is sometimes expressed as

[0400]

number

[0401] It is described as:

[0402] If a 9th order polynomial is used as the target polynomial, then the 9th order polynomial is:

[0403]

number

[0404] where the values ​​of a8,..., and a1 can be 0 or 1, and the quantity of non-zero values ​​in a8,..., and a1 is not greater than 6.

[0405] 8 is a diagram of a second generation structure of pilot symbols according to an embodiment of the present application. As shown in FIG. 8, the seed length is 9 bits, and the seeds can be expressed in binary format as m8, m7, m6, m5, m4, m3, m2, m1, and m0. Of course, the seeds may alternatively be expressed in hexadecimal or decimal format and need to be converted to binary format during operation with the target polynomial.

[0406] It should be noted that an algebraic expression formed by adding (or subtracting) several monomials is called a polynomial. Each monomial in a polynomial is called a term of the polynomial, and the highest degree (degree is also called order) of these monomials is the degree of the polynomial. The number of terms in a polynomial is the number of such monomials whose coefficients are non-zero. For example, the number of terms in the 10th-degree polynomial above is equal to the number of non-zero values ​​in a9,..., and a1 plus 2.

[0407] In the embodiments of the present application, the same target generator polynomial may be used for the pilot symbols in the two orthogonal polarization directions, but since the seeds used in the two polarization directions are different, the pilot symbols output in the two polarization directions are not completely identical accordingly.

[0408] In the scenario where Q pilot symbols need to be generated in Figure 7 or Figure 8, the consecutive bit sequences b0, b1, b2, ..., and b 2Q-1 is obtained based on the target polynomial and the seed. The bit sequence mentioned above is also called Pseudo Random Binary Sequence (PRBS). A bit sequence generated using a 9th order polynomial is sometimes called PRBS9, and a bit sequence generated using a 10th order polynomial is sometimes called PRBS10. The bit sequences b0, b1, b2, ..., and b 2Q-1Every two consecutive bits in b are mapped to one symbol, where b 2t and b 2t+1 is one symbol (2b 2t -1)A+(2b 2t+1 -1)Aj,0≦t

[0409] In this embodiment of the present application, the target polynomial and seed can be determined by designing the values ​​of the coefficients a9,..., and a1 in a 10th-order polynomial, or the values ​​of the coefficients a8,..., and a1 in a 9th-order polynomial, so that the generated pilot symbol sequence in the X polarization direction or the Y polarization direction has good autocorrelation properties, and the pilot symbol sequences in the two polarization directions have good cross-correlation properties. Furthermore, by selecting an appropriate target polynomial and seed, the Q pilot symbols achieve DC balance, which helps the receiver restore signal quality.

[0410] It should be noted that the data frame considered in the present invention includes only pilot symbols and payload symbols (also called pre-framing symbols). This DSP frame structure differs from other existing DSP superframe structures. A DSP superframe typically includes multiple types of symbols, such as frame synchronization symbols used for frame synchronization and distinguishing between two polarization directions, training symbols used for link training, and pilot symbols used for carrier phase recovery. Therefore, in the receiver processing corresponding to the DSP frame considered in the present invention, in addition to supporting carrier phase recovery, pilot symbols must also be used to distinguish between the two polarization directions and for frame synchronization.

[0411] The receiver receives four data streams: the real part sequence data stream in the X polarization direction, Imaginary part sequence data stream in the X polarization direction,​ the real part sequence data stream in the Y polarization direction, and It is necessary to obtain the imaginary part sequence data stream in the Y polarization direction and use pilot symbols to determine whether each data stream corresponds to a real part sequence or an imaginary part sequence in the X polarization direction or the Y polarization direction. In this embodiment of the present invention, the target polynomial and seed are determined by designing the values ​​of coefficients a9,..., and a1 in a 10th-order polynomial or the values ​​of coefficients a8,..., and a1 in a 9th-order polynomial, so that the real part sequence (sometimes called the I channel) and imaginary part sequence (sometimes called the Q channel) of the pilot symbol sequence generated in the two polarization directions have good autocorrelation and correlation properties. More specifically, a total of four sequences with a length of Q bits are generated: The real part of the pilot symbol sequence designed in the X polarization direction, The imaginary part sequence of the pilot symbol sequence designed in the X polarization direction, The real part sequence of the designed pilot symbol sequence in the Y polarization direction, and Imaginary part of the pilot symbol sequence designed in the Y polarization direction has good autocorrelation and cross-correlation properties.

[0412] It should be noted from FIGS. 7 and 8 that the degree of the target polynomial and the number of terms whose coefficients are non-zero affect the complexity of the pilot symbol generation structure. In an embodiment of the present application, when a target polynomial is designed, the degree of the polynomial needs to be constrained to not exceed 10, and the number of non-zero terms of the polynomial needs to be constrained to not exceed 8. When a polynomial is selected, the degree of the target polynomial and the number of non-zero terms need to be selected to be as small as possible, so that the complexity of the pilot symbol generation structure and power consumption are low. It should be further noted that, for a given target polynomial, there may be no seed that can ensure good autocorrelation and cross-correlation in the pilot symbol sequence determined based on the target polynomial and the seed. Therefore, when selecting the target polynomial, not only should the minimum degree and the minimum number of non-zero terms be selected, but also should consider whether it is possible to select the corresponding seed so that the generated pilot symbol sequence and the real and imaginary part sequences of the pilot symbol sequence have good autocorrelation and cross-correlation properties, which can help the receiver restore the signal quality.

[0413] In a possible implementation, the target polynomial is that in Table 1 below: Table 1

[0414] [Table 1]

[0415] In the embodiments of the present application, polynomials of degree 10 or less, especially 9th or 10th order polynomials, are primarily considered because higher order polynomials cannot significantly improve the autocorrelation and cross-correlation characteristics of the generated pilot symbol sequences. Lower order polynomials, for example 6th or 7th order polynomials, have low implementation complexity, but the autocorrelation and cross-correlation characteristics of the generated pilot symbol sequences are usually not sufficiently good. Furthermore, polynomials with no more than 8 terms, especially 9th or 10th order polynomials with 5 or 7 terms, are considered, as these polynomials have low hardware implementation complexity.

[0416] In a possible implementation, an example where N=6144, M=64, and Q=96 is used, and the correspondence between the target polynomial, the seed in the X polarization direction, and the seed in the Y polarization direction is as shown in Table 2 below. The 96 pilot symbols generated in this way have good autocorrelation and cross-correlation properties in the X polarization direction or the Y polarization direction.

[0417] Table 2

[0418] [Table 2] TIFF2025538604000448.tif254170 TIFF2025538604000449.tif254170 TIFF2025538604000450.tif143170

[0419] It should be noted that when a target polynomial is designed, the degree of the polynomial needs to be limited to no more than 10, and the number of non-zero terms of the polynomial needs to be limited to no more than 8. When a polynomial is selected, the degree and number of non-zero terms of the target polynomial need to be selected as small as possible, so that the complexity of the pilot symbol generation structure and power consumption are low. Given a target polynomial, it is possible that no seed exists that can ensure good autocorrelation and cross-correlation for the pilot symbol sequence determined based on the target polynomial and the seed. Therefore, when selecting a target polynomial, not only should the minimum degree and number of non-zero terms be selected, but also whether it is possible to select a corresponding seed that ensures good autocorrelation and cross-correlation properties for the generated pilot symbol sequence and the real and imaginary part sequences of the pilot symbol sequence, helping the receiver restore signal quality.

[0420] In another possible implementation, the target polynomial is that in Table 6 below.

[0421] Table 6

[0422] [Table 3]

[0423] It should be understood that there may be a frequency difference between the transmitting laser and the receiving laser, i.e., a laser frequency offset, which may affect the frame synchronization results performed by the receiving side. The polynomials in Table 6 have good differential autocorrelation and cross-correlation properties, and can achieve good correlation results even when there is a laser frequency offset.

[0424] In a possible implementation, an example where N=6144, M=64, and Q=96 is used, and the correspondence between the target polynomial, the seed in the X polarization direction, and the seed in the Y polarization direction is as in Table 7 below.

[0425] Table 7

[0426] [Table 4] TIFF2025538604000453.tif233170

[0427] It should be understood that there may be a frequency difference between the transmitting laser and the receiving laser, i.e., a laser frequency offset, which may affect the result of the frame synchronization performed by the receiving side. The polynomials and seeds in Table 7 have good differential autocorrelation and differential cross-correlation properties, and can achieve good correlation results even when there is a laser frequency offset.

[0428] Furthermore, in a given polarization direction, the difference between any two of the numbers of pilot symbols in a data frame, -A-Aj, -A+Aj, A-Aj, and A+Aj, respectively, is 2 or less. Furthermore, the number of pilot symbols in -A-Aj is the same as the number of pilot symbols in A+Aj, and the number of pilot symbols in -A+Aj is the same as the number of pilot symbols in A-Aj. This effectively ensures that the number of symbols in each polarization direction is approximately balanced, further ensuring that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality. For example, for Q=96, the numbers of pilot symbols in -A-Aj, -A+Aj, A-Aj, and A+Aj, respectively, may be 23, 25, 25, and 23, with the difference between any two numbers being 2 or less.

[0429] In a possible implementation, the number of pilot symbols is -A-Aj.

[0430]

number

[0431]

number

[0432]

number

[0433]

number

[0434]

number

[0435]

number

[0436]

number

[0437]

number

[0438]

number

[0439]

number

[0440]

number

[0441]

number

[0442]

number

[0443]

number

[0444]

number

[0445]

number

[0446]

number

[0447] Furthermore, in the two polarization directions, the total number of pilot symbols for -A-Aj is Q / 2, the total number of pilot symbols for -A+Aj is Q / 2, the total number of pilot symbols for A-Aj is Q / 2, and the total number of pilot symbols for A+Aj is Q / 2. This effectively ensures a balance between the symbol quantities, and further ensures that the sequence containing pilot symbols achieves DC balance, which may help the receiver restore signal quality.

[0448] In some implementations, the number of pilot symbols in the X polarization direction is -A-Aj.

[0449]

number

[0450]

number

[0451]

number

[0452]

number

[0453]

number

[0454]

number

[0455]

number

[0456]

number

[0457] In another possible implementation, in the X polarization direction, the number of pilot symbols is -A-Aj.

[0458]

number

[0459]

number

[0460]

number

[0461]

number

[0462]

number

[0463]

number

[0464]

number

[0465]

number

[0466] Furthermore, in a certain polarization direction, the number of consecutive identical pilot symbols within a data frame is less than or equal to 4. The pilot symbol sequence obtained under this condition helps to improve the signal quality recovered by the receiver.

[0467] Below, some specific embodiments are described by using an example where N=6144, M=64, and Q=96.

[0468] Embodiment 1: Implementation where the polynomial degree is 9 FIG. 9 is a diagram of another data frame structure according to an embodiment of the present application. Considering dual-polarized DP-16QAM modulation, 96×63=6048 dual-polarized payload symbols are obtained through BCH (126,110) encoding and DP-16QAM dual-polarized modulation. One pilot symbol is inserted before every 63 symbols in the 6048 payload symbols, resulting in a total of 96 pilot symbols, to obtain the data frame (also called DSP frame) structure shown in FIG. 9, i.e., N=6144, M=64, and Q=96. In the X or Y polarization direction, the 96 pilot symbols are generated based on the target polynomial and the seed. Specifically, for a scenario in which 96 pilot symbols need to be generated, a consecutive bit sequence b0, b1, b2, ..., and b3, whose bit length is 96×2=192, is used. 191 is obtained based on the target polynomial and the seed. The bit sequences b0, b1, b2, ..., and b 191 Every two consecutive bits in b are mapped to one symbol, where b 2t and b 2t+1 is one symbol (2b 2t -1)A+(2b 2t+1−1)Aj. Alternatively, the symbol (2b 2t -1)A+(2b 2t+1 -1) Aj may not be a symbol in the constellation diagram of the modulation format used, but may be one of the four symbols in the intermediate region between the four outermost and four innermost symbols in the constellation diagram of the modulation format used.

[0469] 10 is a diagram of a third generation structure of pilot symbols according to an embodiment of the present application. 9 +x 4 +x 3 The process of generating 96 pilot symbols in each of the two polarization directions is shown in Figure 10 when the seed for the X polarization direction is +x+1, the seed for the Y polarization direction is 0x049, and the seed for the X polarization direction is 0x115, i.e., the entry with sequence number 3 in Table 2 is used.

[0470] For the X polarization direction, the input seed is 0x049, which is converted into the binary sequence 001001001, i.e., values ​​m8 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the X polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the X polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the X polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the X polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the X polarization direction.

[0471] For the Y polarization direction, the input seed is 0x115, which is converted into the binary sequence 100010101, i.e., values ​​m8 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the Y polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the Y polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the Y polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the Y polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the Y polarization direction.

[0472] Specifically, the 96 pilot symbols in each of the two polarization directions are shown in Table 3 below.

[0473] Table 3

[0474] [Table 5]

[0475] In the X polarization direction, the numbers of -A-Aj, -A+Aj, A-Aj, and A+Aj pilot symbols are 25, 23, 23, and 25, respectively. In the Y polarization direction, the numbers of -A-Aj, -A+Aj, A-Aj, and A+Aj pilot symbols are 23, 25, 25, and 23, respectively. In a given polarization direction, the difference between any two of the numbers of -A-Aj, -A+Aj, A-Aj, and A+Aj pilot symbols in a data frame is 2 or less. Furthermore, the number of -A-Aj pilot symbols is the same as the number of A+Aj pilot symbols, and the number of -A+Aj pilot symbols is the same as the number of A-Aj pilot symbols. This effectively ensures that the number of symbols in each polarization direction is approximately balanced, further ensuring that the sequence containing pilot symbols achieves DC balance. Furthermore, in the X and Y polarization directions, the total number of pilot symbols that is -A-Aj, the total number of pilot symbols that is -A+Aj, the total number of pilot symbols that is A-Aj, and the total number of pilot symbols that is A+Aj are all 48. This effectively ensures the balance between the symbol quantities and helps the receiver restore the signal quality.

[0476] 11 is a diagram of a first implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. Considering DP-16QAM modulation, the scheme for generating pilot symbols in the X polarization direction and the Y polarization direction is specifically shown in FIG. 11, where the degree of the generating polynomial is 9, and the bit sequence generated by using the 9th degree polynomial is called PRBS9.

[0477] 12(a) to 12(c) are diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. FIG. 12(a) shows the cyclic autocorrelation result of the pilot symbol sequence in the X polarization direction. FIG. 12(b) shows the cyclic autocorrelation result of the pilot symbol sequence in the Y polarization direction. FIG. 12(c) shows the cyclic cross-correlation result of the pilot symbol sequence in the X and Y polarization directions. The normalized amplitudes of the side lobe values ​​of the cyclic autocorrelation functions of the symbol sequences in the two polarization directions are not greater than 0.222, and the normalized amplitudes of the side lobe values ​​of the cyclic cross-correlation functions of the symbol sequences in the two polarization directions are not greater than 0.193.

[0478] 13(a) and 13(b) are diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application.

[0479] The real part of the pilot symbol sequence in the X polarization direction is denoted as (X_I), The imaginary part sequence of the pilot symbol sequence in the X polarization direction is denoted as (X_Q), The real part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_I), The imaginary part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_Q).

[0480] Figures 13(a) and 13(b) show the autocorrelation and cross-correlation characteristics of four sequences: X_I, X_Q, Y_I, and Y_Q, each of which is Q bits in length. Figure 13(a) shows the periodic autocorrelation results of the real part sequence in the X polarization direction (X_I), the imaginary part sequence in the X polarization direction (X_Q), the real part sequence in the Y polarization direction (Y_I), and the imaginary part sequence in the Y polarization direction (Y_Q).

[0481] Figure 13(b) shows The real part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_I & Y_I), The real part sequence in the X polarization direction and the imaginary part sequence in the X polarization direction (X_I&X_Q), The real part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_I&Y_Q), The imaginary part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_Q&Y_I), The real part sequence in the Y polarization direction and the imaginary part sequence in the Y polarization direction (Y_I&Y_Q), The periodic cross-correlation results of the imaginary part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_Q&Y_Q) are shown. Neither the side lobe value of the periodic autocorrelation function nor the absolute value of the normalized amplitude of the periodic cross-correlation function is greater than 0.2917.

[0482] Based on the received signals in the two polarization directions, the receiver performs DSP by using the PS pilot sequence to restore the signal. For example, the correlation values ​​between the received signal and the real part sequence / imaginary part sequence of the PS pilot sequence in the X polarization direction and the real part sequence / imaginary part sequence of the PS pilot sequence in the Y polarization direction are calculated separately, so that the X / Y polarization direction and the real part / imaginary part can be distinguished, and frame synchronization and alignment can be performed. Sequence The designed pilot symbol sequence has good autocorrelation and cross-correlation properties and is DC balanced, which helps the receiver to improve the quality of the recovered signal.

[0483] Embodiment 2: Implementation where the polynomial degree is 10 14 is a diagram of a fourth generation structure of pilot symbols according to an embodiment of the present application. 10 +x 9 +x 4The process of generating 96 pilot symbols in each of the two polarization directions is shown in Figure 14 when the seed for the X polarization direction is +x+1, the seed for the Y polarization direction is 0x12A, and the seed for the X polarization direction is 0x039, i.e., the entry with sequence number 36 in Table 2 is used.

[0484] For the X polarization direction, the input polarization seed is 0x12A, which is converted into the binary sequence 0100101010, i.e., values ​​m9 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the X polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the X polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the X polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the X polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the X polarization direction.

[0485] For the Y polarization direction, the input seed is 0x039, which is converted into the binary sequence 0000111001, i.e., values ​​m9 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the Y polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the Y polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the Y polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the Y polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the Y polarization direction.

[0486] Specifically, the 96 pilot symbols in each of the two polarization directions are shown in Table 4 below.

[0487] Table 4

[0488] [Table 6]

[0489] In the X polarization direction, the numbers of -A-Aj, -A+Aj, A-Aj, and A+Aj pilot symbols are 25, 23, 23, and 25, respectively. In the Y polarization direction, the numbers of -A-Aj, -A+Aj, A-Aj, and A+Aj pilot symbols are 23, 25, 25, and 23, respectively. In a given polarization direction, the difference between any two of the numbers of -A-Aj, -A+Aj, A-Aj, and A+Aj pilot symbols in a data frame is 2 or less. Furthermore, the number of -A-Aj pilot symbols is the same as the number of A+Aj pilot symbols, and the number of -A+Aj pilot symbols is the same as the number of A-Aj pilot symbols. This effectively ensures that the number of symbols in each polarization direction is approximately balanced, further ensuring that the sequence containing pilot symbols achieves DC balance. Furthermore, in the X and Y polarization directions, the total number of pilot symbols that is -A-Aj, the total number of pilot symbols that is -A+Aj, the total number of pilot symbols that is A-Aj, and the total number of pilot symbols that is A+Aj are all 48. This effectively ensures the balance between the symbol quantities and helps the receiver restore the signal quality.

[0490] 15 is a diagram of a second implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. Considering DP-16QAM modulation, the scheme for generating pilot symbols in the X polarization direction and the Y polarization direction is specifically shown in FIG. 15, where the degree of the generating polynomial is 10, and the bit sequence generated by using the 10th-order polynomial is called PRBS10.

[0491] 16(a) to 16(c) are diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. FIG. 16(a) shows the cyclic autocorrelation result of the pilot symbol sequence in the X polarization direction. FIG. 16(b) shows the cyclic autocorrelation result of the pilot symbol sequence in the Y polarization direction. FIG. 16(c) shows the cyclic cross-correlation result of the pilot symbol sequence in the X and Y polarization directions. The normalized amplitudes of the side lobe values ​​of the cyclic autocorrelation functions of the symbol sequences in the two polarization directions are not greater than 0.193, and the normalized amplitudes of the side lobe values ​​of the cyclic cross-correlation functions of the symbol sequences in the two polarization directions are not greater than 0.251.

[0492] 17(a) and 17(b) are diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application.

[0493] The real part of the pilot symbol sequence in the X polarization direction is denoted as (X_I), The imaginary part sequence of the pilot symbol sequence in the X polarization direction is denoted as (X_Q), The real part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_I), The imaginary part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_Q).

[0494] Figures 17(a) and 17(b) show the autocorrelation and cross-correlation characteristics of four sequences: X_I, X_Q, Y_I, and Y_Q, each of which is Q bits in length. Figure 17(a) shows the periodic autocorrelation results of the real part sequence in the X polarization direction (X_I), the imaginary part sequence in the X polarization direction (X_Q), the real part sequence in the Y polarization direction (Y_I), and the imaginary part sequence in the Y polarization direction (Y_Q).

[0495] Figure 17(b) shows The real part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_I & Y_I), The real part sequence in the X polarization direction and the imaginary part sequence in the X polarization direction (X_I&X_Q), The real part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_I&Y_Q), The imaginary part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_Q&Y_I), The real part sequence in the Y polarization direction and the imaginary part sequence in the Y polarization direction (Y_I&Y_Q), The periodic cross-correlation results of the imaginary part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_Q&Y_Q) are shown. Neither the side lobe value of the periodic autocorrelation function nor the absolute value of the normalized amplitude of the periodic cross-correlation function is greater than 0.2917.

[0496] Based on the received signals in the two polarization directions, the receiver performs DSP by using the PS pilot sequence to restore the signal. For example, the correlation values ​​between the received signal and the real part sequence / imaginary part sequence of the PS pilot sequence in the X polarization direction and the real part sequence / imaginary part sequence of the PS pilot sequence in the Y polarization direction are calculated separately, so that the X / Y polarization direction and the real part / imaginary part can be distinguished, and frame synchronization and alignment can be performed. Sequence The designed pilot symbol sequence has good autocorrelation and cross-correlation properties and is DC balanced, which helps the receiver to improve the quality of the recovered signal.

[0497] Based on the above description, in an embodiment of the present application, in a data frame containing N symbols, every M consecutive symbols contain a pilot symbol at a fixed position and M-1 payload symbols, where N=M×Q. The Q pilot symbols in the data frame are generated using a target polynomial and a seed, where the Q pilot symbols are DC-balanced, the degree of the target polynomial is 10 or less, and the number of terms of the target polynomial is between 2 and 8. It can be seen that a simple target polynomial is designed in the present application to generate the pilot symbols. Correspondingly, a simple hardware structure can be used for implementation. Furthermore, the pilot symbols generated in the above manner have good autocorrelation and cross-correlation properties and are DC-balanced, which helps the receiving side restore signal quality.

[0498] It should be noted that some optical transport network architectures currently support transmission rates of 400 Gbps and 800 Gbps. At 400 Gbps, if dual-polarization 16-quadrature amplitude modulation (DP-16QAM) modulation is used, the corresponding required baud rate is typically about 60 Gbaud. At 800 Gbps, if DP-16QAM modulation is used, the corresponding required baud rate is typically about 120 Gbaud. With the growth of services, metropolitan and data center transmission scenarios have increasingly higher transmission rate requirements. For example, at transmission rates of 1.2 Tbps and 1.6 Tbps, if DP-16QAM modulation and a single-wavelength transmission method are used, the corresponding baud rates are about 180 Gbaud and 240 Gbaud. At the same transmission rate, if a lower-order modulation, such as Quadrature Phase Shift Keying (DP-QPSK), is used, a higher baud rate is required. If a higher-order modulation, such as DP-32QAM or DP-64QAM, is used, the required baud rate is lower, but the transmission distance is limited. The higher transmission rates required in optical transport networks correspond to higher required baud rates and higher device power consumption. Currently, there are no low-power devices with baud rates higher than 140 Gbaud. In metro communication and data center transmission scenarios, low power consumption is usually required for implementation. Multiple data frames are carried by multiple optical signals for transmission, resulting in parallel data streams. This can improve the overall transmission rate while maintaining the current baud rate and current modulation order. For example, multiple optical signals have different wavelengths, and multiple optical signals with different wavelengths are transmitted over the same optical fiber; this is also known as wavelength division multiplexing (WDM) transmission.In another example, multiple optical signals are transmitted over multiple different optical fibers, also known as parallel single mode (PSM). The following embodiments are applicable to metro telecommunications transmission and data center transmission scenarios that do not require devices with higher baud rates and require low power consumption.

[0499] Embodiment 3 Two data frames are considered: the first data frame and the second data frame. For the structure of the first and second data frames, see the diagram of the data frame structure in Figure 9. Considering dual-polarized DP-16QAM modulation, 96 × 63 = 6048 dual-polarized payload symbols are obtained through BCH (126, 110) encoding and DP-16QAM dual-polarized modulation. One pilot symbol is inserted before every 63 symbols in the 6048 payload symbols, resulting in a total of 96 pilot symbols, resulting in the data frame (also called DSP frame) structure shown in Figure 9, i.e., N = 6144, M = 64, and Q = 96. In the X or Y polarization direction, 96 pilot symbols are generated based on the target polynomial and seed.

[0500] For the first data frame, in the X polarization direction, 96 pilot symbols are generated based on the first target polynomial and the first seed; in the Y polarization direction, 96 pilot symbols are generated based on the first target polynomial and the second seed.

[0501] For the second data frame, in the X polarization direction, 96 pilot symbols are generated based on the second target polynomial and the third seed; in the Y polarization direction, 96 pilot symbols are generated based on the second target polynomial and the fourth seed.

[0502] FIG. 18 is a diagram of a transmission scenario of multiple data frame streams according to an embodiment of the present application. In this embodiment, two dual-polarized symbol streams are obtained by BCH (126, 110) encoding and DP-16QAM dual-polarized modulation. In each dual-polarized symbol stream, one pilot symbol is inserted before every 63 symbols of every 6048 payload symbols according to the framing solution described above, resulting in a total of 96 pilot symbols to obtain one data frame. In other words, a first data frame is placed in one data frame stream obtained by performing framing on one of the two dual-polarized symbol streams, and a second data frame is placed in the other data frame stream obtained by performing framing on the dual-polarized symbol stream of the two dual-polarized symbol streams. The two data frame streams are carried by multiple optical signals for transmission, as shown in the example in FIG. 18(a). In this embodiment, two data frame streams are transmitted on different wavelengths. In a 1.6 TE scenario, the rate of each data frame stream is approximately 800 Gbit / s.

[0503] In this embodiment, the first target polynomial and the second target polynomial are the same target polynomial. The first seed and the third seed are the same and are called seeds in the X polarization direction. The second seed and the fourth seed are the same and are called seeds in the Y polarization direction. In other words, the same 96 pilot symbols are used in the first data frame and the second data frame. The 9th order target polynomial is x 9 +x 8 +x 5 +x 4The process of generating 96 pilot symbols in each of the two polarization directions is shown in Figure 19 when the seed in the X polarization direction is +1, the seed in the Y polarization direction is 0x175, and the seed in the Y polarization direction is 0x03D, i.e., the entry with sequence number 23 in Table 2 is used.

[0504] 19 is a diagram of a fifth generation structure of pilot symbols according to an embodiment of the present application. In the X polarization direction, the input polarization seed is 0x175 and is converted into a binary sequence 101110101, i.e., values ​​m8 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the X polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the X polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the X polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the X polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the X polarization direction.

[0505] For the Y polarization direction, the input seed is 0x03D, which is converted into the binary sequence 000111101, i.e., values ​​m8 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the Y polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the Y polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the Y polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the Y polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the Y polarization direction.

[0506] Specifically, the 96 pilot symbols in each of the two polarization directions are shown in Table 5 below.

[0507] Table 5

[0508] [Table 7]

[0509] In the X polarization direction, the numbers of pilot symbols with -A-Aj, -A+Aj, A-Aj, and A+Aj are all 24. In the Y polarization direction, the numbers of pilot symbols with -A-Aj, -A+Aj, A-Aj, and A+Aj are 25, 23, 23, and 25, respectively. In a given polarization direction, the difference between the numbers of pilot symbols with -A-Aj, -A+Aj, A-Aj, and A+Aj in a data frame is no more than 2. Furthermore, the number of pilot symbols with -A-Aj is the same as the number of pilot symbols with A+Aj, and the number of pilot symbols with -A+Aj is the same as the number of pilot symbols with A-Aj. This effectively ensures that the number of symbols in each polarization direction is approximately balanced, and the sequence containing pilot symbols achieves DC balance, helping the receiver restore signal quality.

[0510] Figure 20 is a diagram of a third implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. Considering DP-16QAM modulation, the scheme for generating pilot symbols in the X polarization direction and the Y polarization direction is specifically shown in Figure 20, where the degree of the generating polynomial is 9, and the bit sequence generated by using the 9th degree polynomial is called PRBS9.

[0511] 21(a) to 21(c) are other diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. FIG. 21(a) shows the cyclic autocorrelation result of the pilot symbol sequence in the X polarization direction. FIG. 21(b) shows the cyclic autocorrelation result of the pilot symbol sequence in the Y polarization direction. FIG. 21(c) shows the cyclic cross-correlation result of the pilot symbol sequence in the X and Y polarization directions. The normalized amplitudes of the side lobe values ​​of the cyclic autocorrelation functions of the symbol sequences in the two polarization directions are not greater than 0.180, and the normalized amplitudes of the side lobe values ​​of the cyclic cross-correlation functions of the symbol sequences in the two polarization directions are not greater than 0.225.

[0512] 22(a) and 22(b) are diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application.

[0513] The real part of the pilot symbol sequence in the X polarization direction is denoted as (X_I), The imaginary part sequence of the pilot symbol sequence in the X polarization direction is denoted as (X_Q), The real part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_I), The imaginary part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_Q).

[0514] Figures 22(a) and 22(b) show the autocorrelation and cross-correlation characteristics of four sequences: X_I, X_Q, Y_I, and Y_Q, each of which is Q bits in length. Figure 22(a) shows the periodic autocorrelation results of the real part sequence in the X polarization direction (X_I), the imaginary part sequence in the X polarization direction (X_Q), the real part sequence in the Y polarization direction (Y_I), and the imaginary part sequence in the Y polarization direction (Y_Q).

[0515] Figure 22(b) shows The real part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_I & Y_I), The real part sequence in the X polarization direction and the imaginary part sequence in the X polarization direction (X_I&X_Q), The real part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_I&Y_Q), The imaginary part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_Q&Y_I), The real part sequence in the Y polarization direction and the imaginary part sequence in the Y polarization direction (Y_I&Y_Q), The periodic cross-correlation results of the imaginary part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_Q&Y_Q) are shown. Neither the side lobe value of the periodic autocorrelation function nor the absolute value of the normalized amplitude of the periodic cross-correlation function is greater than 0.292.

[0516] Based on the received signals in two polarization directions, the receiver performs DSP by using the PS pilot sequence to restore the signal. For example, the correlation value between the received signal and the real part sequence and the imaginary part sequence of the PS pilot sequence in the X polarization direction, and the correlation value between the received signal and the real part sequence and the imaginary part sequence of the PS pilot sequence in the Y polarization direction are calculated separately, so that the X polarization direction and the Y polarization direction and the real part and the imaginary part can be distinguished, and frame synchronization and alignment can be performed. Sequence The designed pilot symbol sequence has good autocorrelation and cross-correlation properties and is DC balanced, which helps the receiver to improve the quality of the recovered signal.

[0517] It should be noted that this embodiment considers that the two data frame streams are transmitted on different wavelengths and the 96 pilot symbols in each data frame stream are generated by using the same target polynomial. In some other specific applications, the pilot symbol sequences in the two data frame streams are generated by using different target polynomials. In some other specific applications, the pilot symbol sequences in the two data frame streams are generated by using the same target polynomial but different seeds. In some other specific applications, the two data frame streams are transmitted on two optical fibers.

[0518] It should be noted that in some other specific applications, the number of data frame streams is greater than two. As shown in FIG. 18(b), W dual-polarized symbol streams are obtained through FEC encoding and modulation. In each dual-polarized symbol stream, one pilot symbol is inserted before every (M-1) × Q payload symbols according to the framing solution described above, resulting in a total of Q pilot symbols to obtain one data frame. In this way, a total of W data frame streams are obtained. The W data frame streams are carried by multiple optical signals for transmission. For example, the W data frame streams are respectively carried by W optical signals. In one example, any two of the W optical signals have different wavelengths, and the W optical signals are transmitted through the same optical fiber. In another example, all of the W optical signals have the same wavelength, and the W optical signals are respectively transmitted through W optical fibers.

[0519] Below, some specific embodiments will be described based on Table 7.

[0520] Embodiment 4: The target polynomial is x^10+x^9+x^6+x+1, the seed in the X polarization direction is 0x0B4, and the seed in the Y polarization direction is 0x2D1.

[0521] Considering dual-polarized DP-16QAM modulation, as shown in Figure 9, 96 × 63 = 6048 dual-polarized payload symbols are obtained through BCH (126, 110) encoding and DP-16QAM dual-polarized modulation. One pilot symbol is inserted before every 63 symbols in the 6048 payload symbols, resulting in a total of 96 pilot symbols, resulting in the data frame (also called DSP frame) structure shown in Figure 14, i.e., N = 6144, M = 64, and Q = 96. In the X or Y polarization direction, the 96 pilot symbols are generated based on the target polynomial and seed. Specifically, for a scenario in which 96 pilot symbols need to be generated, a consecutive bit sequence b0, b1, b2, ..., and b3, whose bit length is 96 × 2 = 192, is used. 191 is obtained based on the target polynomial and the seed. The bit sequences b0, b1, b2, ..., and b 191 Every two consecutive bits in b are mapped to one symbol, where b 2t and b 2t+1 is one symbol (2b 2t -1)A+(2b 2t+1 −1)Aj. Alternatively, the symbol (2b 2t -1)A+(2b 2t+1 -1) Aj may not be a symbol in the constellation diagram of the modulation format used, but may be one of the four symbols in the intermediate region between the four outermost and four innermost symbols in the constellation diagram of the modulation format used.

[0522] 23 is a diagram of a sixth generation structure of pilot symbols according to an embodiment of the present application. 10 +x 9 +x6 The process of generating 96 pilot symbols in each of the two polarization directions is shown in Figure 23 when the seed for the X polarization direction is +x+1, the seed for the Y polarization direction is 0x0B4, and the seed for the X polarization direction is 0x2D1, i.e., the entry with sequence number 9 in Table 7 is used.

[0523] For the X polarization direction, the input polarization seed is 0x0B4, which is converted into the binary sequence 0010110100, i.e., values ​​m9 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the X polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the X polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the X polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the X polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the X polarization direction.

[0524] For the Y polarization direction, the input seed is 0x2D1, which is converted into the binary sequence 1011010001, i.e., values ​​m9 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the Y polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the Y polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the Y polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the Y polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the Y polarization direction.

[0525] Specifically, the 96 pilot symbols in each of the two polarization directions are shown in Table 8 below.

[0526] Table 8

[0527] [Table 8]

[0528] 24 is a diagram of a fourth implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. Considering DP-16QAM modulation, the scheme for generating pilot symbols in the X polarization direction and the Y polarization direction is specifically shown in FIG. 16(a) to FIG. 16(c), where the degree of the generating polynomial is 10, and the bit sequence generated by using the 10th-order polynomial is called PRBS10.

[0529] 25(a) and 25(b) are diagrams of correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. Fig. 25(a) shows the cyclic autocorrelation results obtained by taking the difference between every two adjacent symbols in the pilot symbol sequence in the X and Y polarization directions. Fig. 25(b) shows the cyclic differential cross-correlation results of the pilot symbol sequence in the X and Y polarization directions. The normalized amplitudes of the side lobe values ​​of the cyclic differential autocorrelation functions of the symbol sequence in the two polarization directions are not greater than 0.179, and the normalized amplitudes of the side lobe values ​​of the cyclic differential cross-correlation functions of the symbol sequence in the two polarization directions are not greater than 0.222.

[0530] 26(a) and 26(b) are diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application.

[0531] The real part of the pilot symbol sequence in the X polarization direction is denoted as (X_I), The imaginary part sequence of the pilot symbol sequence in the X polarization direction is denoted as (X_Q), The real part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_I), The imaginary part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_Q).

[0532] Figures 26(a) and 26(b) show the autocorrelation and cross-correlation characteristics of four sequences: X_I, X_Q, Y_I, and Y_Q, each of which is Q bits in length. Figure 26(a) shows the cyclic differential autocorrelation results of the real part sequence in the X polarization direction (X_I), the imaginary part sequence in the X polarization direction (X_Q), the real part sequence in the Y polarization direction (Y_I), and the imaginary part sequence in the Y polarization direction (Y_Q).

[0533] Figure 26(b) shows The real part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_I & Y_I), The real part sequence in the X polarization direction and the imaginary part sequence in the X polarization direction (X_I&X_Q), The real part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_I&Y_Q), The imaginary part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_Q&Y_I), The real part sequence in the Y polarization direction and the imaginary part sequence in the Y polarization direction (Y_I&Y_Q), The periodic differential cross-correlation results of the imaginary part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_Q&Y_Q) are shown. Neither the side lobe value of the periodic differential autocorrelation function nor the absolute value of the normalized amplitude of the periodic differential cross-correlation function is greater than 0.2709.

[0534] Based on the received signals in two polarization directions, the receiver performs DSP by using the PS pilot sequence to recover the signal. For example, the differential correlation value between the received signal and the sequence symbols of the PS pilot sequence in X polarization and Y polarization is calculated separately, so that the polarization directions can be distinguished, frame synchronization and alignment can be performed, and the PS pilot sequence can be used to recover the signal. Sequence The designed pilot symbol sequence has good differential autocorrelation and cross-correlation properties and is DC balanced, which helps the receiver to improve the quality of the recovered signal.

[0535] Embodiment 5: The target polynomial is x^10+x^9+x^4+x+1, the seed in the X polarization direction is 0x128, and the seed in the Y polarization direction is 0x12A.

[0536] 27 is a diagram of a seventh generation structure of pilot symbols according to an embodiment of the present application. 10 +x 9 +x 4 The process of generating 96 pilot symbols in each of the two polarization directions is shown in Figure 27 when the seed for the X polarization direction is 0x128 and the seed for the Y polarization direction is 0x12A, i.e., the entry with sequence number 12 in Table 7 is used.

[0537] For the X polarization direction, the input polarization seed is 0x128, which is converted into the binary sequence 0100101000, i.e., values ​​m9 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the X polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the X polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the X polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the X polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the X polarization direction.

[0538] For the Y polarization direction, the input seed is 0x12A, which is converted into the binary sequence 010010101, i.e., values ​​m9 to m0. If two consecutive bits are output in sequence as 1 and 0, the pilot symbol in the Y polarization direction is A-Aj. If two consecutive bits are output in sequence as 0 and 0, the pilot symbol in the Y polarization direction is -A-Aj. If two consecutive bits are output in sequence as 1 and 1, the pilot symbol in the Y polarization direction is A+Aj. If two consecutive bits are output in sequence as 0 and 1, the pilot symbol in the Y polarization direction is -A+Aj. By analogy, it is possible to obtain 96 pilot symbols in the Y polarization direction.

[0539] Specifically, the 96 pilot symbols in each of the two polarization directions are shown in Table 9 below.

[0540] Table 9

[0541] [Table 9]

[0542] Figure 28 is a diagram of a fifth implementation procedure for generating pilot symbols based on DP-16QAM modulation according to an embodiment of the present application. Considering DP-16QAM modulation, the method for generating pilot symbols in the X polarization direction and the Y polarization direction is specifically shown in Figure 28, where the degree of the generating polynomial is 10, and the bit sequence generated by using the 10th-order polynomial is called PRBS10.

[0543] 29(a) and 29(b) are other diagrams of correlation and cross-correlation characteristics corresponding to pilot symbols according to an embodiment of the present application. Figure 29(a) shows the cyclic autocorrelation results obtained by taking the difference between every two adjacent symbols in the pilot symbol sequence in the X and Y polarization directions. Figure 29(b) shows the cyclic differential cross-correlation results of the pilot symbol sequence in the X and Y polarization directions. The normalized amplitudes of the side lobe values ​​of the cyclic differential autocorrelation functions of the symbol sequence in the two polarization directions are not greater than 0.178, and the normalized amplitudes of the side lobe values ​​of the cyclic differential cross-correlation functions of the symbol sequence in the two polarization directions are not greater than 0.222.

[0544] 30(a) and 30(b) are other diagrams reflecting autocorrelation and cross-correlation properties according to an embodiment of the present application.

[0545] The real part of the pilot symbol sequence in the X polarization direction is denoted as (X_I), The imaginary part sequence of the pilot symbol sequence in the X polarization direction is denoted as (X_Q), The real part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_I), The imaginary part of the pilot symbol sequence in the Y polarization direction is denoted as (Y_Q).

[0546] Figures 30(a) and 30(b) show the autocorrelation and cross-correlation characteristics of four sequences: X_I, X_Q, Y_I, and Y_Q, each of which is Q bits in length. Figure 30(a) shows the cyclic differential autocorrelation results of the real part sequence in the X polarization direction (X_I), the imaginary part sequence in the X polarization direction (X_Q), the real part sequence in the Y polarization direction (Y_I), and the imaginary part sequence in the Y polarization direction (Y_Q).

[0547] Figure 30(b) shows The real part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_I & Y_I), The real part sequence in the X polarization direction and the imaginary part sequence in the X polarization direction (X_I&X_Q), The real part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_I&Y_Q), The imaginary part sequence in the X polarization direction and the real part sequence in the Y polarization direction (X_Q&Y_I), The real part sequence in the Y polarization direction and the imaginary part sequence in the Y polarization direction (Y_I&Y_Q), The periodic differential cross-correlation results of the imaginary part sequence in the X polarization direction and the imaginary part sequence in the Y polarization direction (X_Q&Y_Q) are shown. Neither the side lobe value of the periodic differential autocorrelation function nor the absolute value of the normalized amplitude of the periodic differential cross-correlation function is greater than 0.2709.

[0548] Based on the received signals in two polarization directions, the receiver performs DSP by using the PS pilot sequence to recover the signal. For example, the differential correlation value between the received signal and the sequence symbols of the PS pilot sequence in X polarization and Y polarization is calculated separately, so that the polarization directions can be distinguished, frame synchronization and alignment can be performed, and the PS pilot sequence can be used to recover the signal. Sequence The designed pilot symbol sequence has good differential autocorrelation and cross-correlation properties and is DC balanced, which helps the receiver to improve the quality of the recovered signal.

[0549] The data transmission device provided in the embodiment of the present application will be described below.

[0550] 31 is a structural diagram of a data transmission device used at the transmitting side according to an embodiment of the present application. As shown in FIG. 31, the data transmission device includes a processing unit 101 and a sending unit 102. The processing unit 101 is configured to perform the operation of step 401 in the embodiment shown in FIG. 4. The sending unit 102 is configured to perform the operation of step 402 in the embodiment shown in FIG. 4. For specific operations, please refer to the relevant description of the embodiment shown in FIG. 4. The details will not be described again here.

[0551] 32 is a diagram of the structure of a data transmission device used at the receiving end according to an embodiment of the present application. As shown in FIG. 32, the data transmission device includes a processing unit 201 and a receiving unit 202. The receiving unit 202 is configured to receive data frames transmitted from the transmitting end via a channel. The processing unit 201 is configured to perform dispersion compensation, synchronization, phase recovery, and other operations.

[0552] It should be understood that the devices provided in the present application may alternatively be implemented in other ways. For example, the division into units in the above-described devices is merely a logical division of functions, and other divisions may be used in actual implementation. For example, multiple units or components may be combined or integrated into another system. Furthermore, the functional units in the embodiments of the present application may be integrated into one processing unit or may be independent physical units, or two or more functional units may be integrated into one processing unit. The integrated units may be implemented in the form of hardware or software functional units.

[0553] FIG. 33 is a diagram of another structure of a data transmission device according to an embodiment of the present application. As shown in FIG. 33, the data transmission device includes a processor 301, a memory 302, and a transceiver 303. The processor 301, the memory 302, and the transceiver 303 are interconnected via lines. The memory 302 is configured to store program instructions and data. Specifically, the transceiver 303 is configured to perform data transmission and reception operations, and the processor 301 is configured to perform operations other than data transmission and reception. In a possible implementation, the processor 301 may include the processing unit 101 shown in FIG. 31, and the transceiver 303 includes the transmitting unit 102 shown in FIG. 31. In another possible implementation, the processor 301 may include the processing unit 201 shown in FIG. 32, and the transceiver 303 includes the receiving unit 202 shown in FIG. 32.

[0554] It should be noted that the processor shown in FIG. 33 may be a general-purpose central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The memory shown in FIG. 33 may store an operating system and other application programs. When the technical solutions provided in the embodiments of the present application are implemented by using software or firmware, the program code used to implement the technical solutions provided in the embodiments of the present application is stored in the memory and executed by the processor. In an embodiment, the processor may include a memory therein. In another embodiment, the processor and the memory are two independent structures.

[0555] It will be clearly understood by those skilled in the art that for convenient and concise description, the detailed operation processes of the aforementioned systems, devices and units can be referred to the corresponding processes in the aforementioned method embodiments, and the details will not be described again here.

[0556] Those skilled in the art can understand that all or part of the steps in the above embodiments may be implemented by hardware or a program instructing related hardware. The program may be stored in a computer-readable storage medium. The storage medium may be a read-only memory, a random-access memory, or the like. Whether the functions are performed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use various methods to implement the described functions for each specific application, but the implementation form should not be interpreted as going beyond the scope of the present application.

[0557] When software is used to implement the functions, all or part of the method steps described in the above embodiments may be embodied in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of the present application are performed, in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or another programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio, or microwave) transmission. The computer-readable storage medium may be any available medium accessible by a computer or a data storage device, such as a server or data center, that integrates one or more available media. The usable media may be magnetic media (e.g., floppy disk, hard disk, or magnetic tape), optical media (e.g., DVD), semiconductor media (e.g., Solid-State Drive (SSD)), or the like.

Claims

1. 1. A data transmission method comprising: generating a data frame, in a polarization direction, the data frame including N symbols, one pilot symbol at a fixed position for every M consecutive symbols among the N symbols, and M−1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1, the Q pilot symbols are generated by using a target polynomial and a seed, each pilot symbol being one of four complex numbers: −A−Aj, −A+Aj, A−Aj, and A+Aj, where A is a real number, the Q pilot symbols are DC balanced, the degree of the target polynomial is less than or equal to 10, and the number of terms of the target polynomial is greater than or equal to 2 and less than or equal to 8; and transmitting the data frame; A method comprising:

2. 10. The method of claim 1, wherein the target polynomial is: x^9+x^4+x^3+x+1; x^9+x^5+x^4+x+1; x^9+x^8+x^5+x^4+1; x^9+x^8+x^6+x^5+1; x^10+x^4+x^3+x+1; x^10+x^5+x^2+x+1; x^10+x^8+x^5+x+1; x^10+x^9+x^4+x+1; x^10+x^9+x^5+x^2+1; x^10+x^9+x^6+x+1; x^10+x^9+x^7+x^6+1; x^10+x^9+x^8+x^5+1; x^10+x^8+x^6+x^5+x^3+x+1; x^10+x^8+x^7+x^3+x^2+x+1; x^10+x^8+x^7+x^6+x^2+x+1; x^10+x^9+x^7+x^5+x^4+x^2+1; x^10+x^9+x^8+x^4+x^3+x^2+1; or x^10+x^9+x^8+x^7+x^3+x^2+1 One of the methods.

3. 3. The method of claim 1, wherein each pilot symbol is located at the beginning of M consecutive symbols in which the pilot symbol is located.

4. 4. The method according to claim 1, wherein a sequence comprising Q pilot symbols in a first polarization direction is different from a sequence comprising Q pilot symbols in a second polarization direction, and wherein the first polarization direction and the second polarization direction are orthogonal to each other.

5. 5. The method according to claim 1, wherein N=6144, M=64, and Q=96, and the correspondence between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is as follows: the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x002, and a seed in the second polarization direction: 0x115; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x002, and a seed in the second polarization direction: 0x02B; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x049, and a seed in the second polarization direction: 0x115; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x049, and a seed in the second polarization direction: 0x02B; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x115, and a seed in the second polarization direction: 0x08D; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x08D, and a seed in the second polarization direction: 0x02B; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x098, and a seed in the second polarization direction: 0x0FE; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x098, and a seed in the second polarization direction: 0x0BF; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x098, and a seed in the second polarization direction: 0x17F; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x14C, and a seed in the second polarization direction: 0x0FE; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x14C, and a seed in the second polarization direction: 0x0BF; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x14C, and a seed in the second polarization direction: 0x17F the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x0A6, and a seed in the second polarization direction: 0x0FE; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x0A6, and a seed in the second polarization direction: 0x0BF; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x0A6, and a seed in the second polarization direction: 0x17F; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x1D4, and a seed in the second polarization direction: 0x11E; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x1D4, and a seed in the second polarization direction: 0x03D; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x1D4, and a seed in the second polarization direction: 0x08F; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x0EA, and a seed in the second polarization direction: 0x11E; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x0EA, and a seed in the second polarization direction: 0x03D; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x0EA, and a seed in the second polarization direction: 0x08F; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x11E, and a seed in the second polarization direction: 0x175; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x175, and a seed in the second polarization direction: 0x03D; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x175, and a seed in the second polarization direction: 0x08F; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x16A, and a seed in the second polarization direction: 0x1E1; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x16A, and a seed in the second polarization direction: 0x1C3; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x1E1, and a seed in the second polarization direction: 0x069; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x1E1, and a seed in the second polarization direction: 0x113; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x069, and a seed in the second polarization direction: 0x1C3; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x1C3, and a seed in the second polarization direction: 0x113; the target polynomial: x^10+x^4+x^3+x+1, a seed in the first polarization direction: 0x0E6, and a seed in the second polarization direction: 0x36E; the target polynomial: x^10+x^5+x^2+x+1, a seed in the first polarization direction: 0x3DC, and a seed in the second polarization direction: 0x36A; the target polynomial: x^10+x^5+x^2+x+1, a seed in the first polarization direction: 0x36A, and a seed in the second polarization direction: 0x35E; the target polynomial: x^10+x^5+x^2+x+1, a seed in the first polarization direction: 0x36A, and a seed in the second polarization direction: 0x1AF; the target polynomial: x^10+x^8+x^5+x+1, a seed in the first polarization direction: 0x1FD, and a seed in the second polarization direction: 0x3A7; the target polynomial: x^10+x^9+x^4+x+1, a seed in the first polarization direction: 0x12A, and a seed in the second polarization direction: 0x039; the target polynomial: x^10+x^9+x^4+x+1, a seed in the first polarization direction: 0x12A, and a seed in the second polarization direction: 0x107; the target polynomial: x^10+x^9+x^4+x+1, a seed in the first polarization direction: 0x039, and a seed in the second polarization direction: 0x295; the target polynomial: x^10+x^9+x^4+x+1, a seed in the first polarization direction: 0x295, and a seed in the second polarization direction: 0x107; the target polynomial: x^10+x^9+x^5+x^2+1, a seed in the first polarization direction: 0x26A, and a seed in the second polarization direction: 0x03A; the target polynomial: x^10+x^9+x^6+x+1, a seed in the first polarization direction: 0x1A2, and a seed in the second polarization direction: 0x379; the target polynomial: x^10+x^9+x^6+x+1, a seed in the first polarization direction: 0x1A2, and a seed in the second polarization direction: 0x3EF; the target polynomial: x^10+x^9+x^6+x+1, a seed in the first polarization direction: 0x2D1, and a seed in the second polarization direction: 0x379; the target polynomial: x^10+x^9+x^6+x+1, a seed in the first polarization direction: 0x2D1, and a seed in the second polarization direction: 0x3EF; the target polynomial: x^10+x^9+x^7+x^6+1, a seed in the first polarization direction: 0x3CC, and a seed in the second polarization direction: 0x1E2; the target polynomial: x^10+x^9+x^8+x^5+1, a seed in the first polarization direction: 0x170, and a seed in the second polarization direction: 0x14D; the target polynomial: x^10+x^9+x^8+x^5+1, a seed in the first polarization direction: 0x0B8, and a seed in the second polarization direction: 0x14D; the target polynomial: x^10+x^9+x^8+x^5+1, a seed in the first polarization direction: 0x299, and a seed in the second polarization direction: 0x14D; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x354, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x17C, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x1AA, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x06A, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x3E6, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2A9, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2F9, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x0D5, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2AD, and a seed in the second polarization direction: 0x1F3; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2AD, and a seed in the second polarization direction: 0x14B; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2AD, and a seed in the second polarization direction: 0x297; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2AD, and a seed in the second polarization direction: 0x12F; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x3AC; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x1D6; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x075; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x0ED; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x0EB; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x0D4, and a seed in the second polarization direction: 0x3AC; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x0D4, and a seed in the second polarization direction: 0x1D6; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x0D4, and a seed in the second polarization direction: 0x075; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x0D4, and a seed in the second polarization direction: 0x0EB; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x3AC, and a seed in the second polarization direction: 0x01A; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x01A, and a seed in the second polarization direction: 0x1D6; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x01A, and a seed in the second polarization direction: 0x075; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x01A, and a seed in the second polarization direction: 0x0EB; the target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, a seed in the first polarization direction: 0x1B0, and a seed in the second polarization direction: 0x3F4; the target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, a seed in the first polarization direction: 0x1B0, and a seed in the second polarization direction: 0x1FA; the target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, a seed in the first polarization direction: 0x3F4, and a seed in the second polarization direction: 0x13D; the target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, a seed in the first polarization direction: 0x1FA, and a seed in the second polarization direction: 0x13D; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x35C, and a seed in the second polarization direction: 0x2EE; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x0DC, and a seed in the second polarization direction: 0x2EE; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x33A, and a seed in the second polarization direction: 0x2EE; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x26E, and a seed in the second polarization direction: 0x2EE; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x2B9; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x1B9; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x275; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x39D; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x173; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x0EB; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x39B; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x337; the target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, a seed in the first polarization direction: 0x0C6, and a seed in the second polarization direction: 0x157; the target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, a seed in the first polarization direction: 0x0C6, and a seed in the second polarization direction: 0x2D7; the target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, a seed in the first polarization direction: 0x263, and a seed in the second polarization direction: 0x157; the target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, a seed in the first polarization direction: 0x263, and a seed in the second polarization direction: 0x2D7; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x130; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x298; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x34C; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x261; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x01F; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x130, and a seed in the second polarization direction: 0x014; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x130, and a seed in the second polarization direction: 0x282; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x298, and a seed in the second polarization direction: 0x014; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x298, and a seed in the second polarization direction: 0x282; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x014, and a seed in the second polarization direction: 0x34C; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x014, and a seed in the second polarization direction: 0x261; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed for the first polarization direction: 0x34C, and a seed for the second polarization direction: 0x282; or the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed for the first polarization direction: 0x282, and a seed for the second polarization direction: 0x261 One of the methods.

6. 6. The method according to claim 1, wherein N=6144, M=64, and Q=96, the target polynomial is x^9+x^4+x^3+x+1, a seed for the first polarization direction is 0x049, a seed for the second polarization direction is 0x115, and the first polarization direction and the second polarization direction are orthogonal to each other; The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+ -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+ Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, A+Aj, A+Aj, A+Aj, A+Aj, A+Aj, A+Aj, A+Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A +Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, and A+Aj; and The 96 pilot symbols in the second wave direction are: A-Aj, A-Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A -Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A-Aj, A-Aj, A-Aj, -A+Aj, A-Aj, - A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A +Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, -A-Aj , -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, A-Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, A+Aj, -A- Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, A-Aj, -A+Aj, -A +Aj, A+Aj, -A-Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, and The method is A+Aj.

7. 6. The method according to claim 1, wherein N=6144, M=64, and Q=96, the target polynomial is x^10+x^9+x^4+x+1, the seed in the first polarization direction is 0x12A, the seed in the second polarization direction is 0x039, and the first polarization direction and the second polarization direction are orthogonal to each other; The 96 pilot symbols in the first polarization direction are, in order: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,- j, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, and -A+Aj; and The 96 pilot symbols in the second wave direction are: A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A- Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, A+Aj, -A +Aj, -A-Aj, A+Aj, A+Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, A-Aj, -A+Aj, A+Aj, A -Aj, A+Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, A+Aj, A+Aj, A-Aj, -A+Aj, -A+Aj, -A- Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, and The method is A+Aj.

8. 8. The method of claim 1, wherein the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in a plurality of optical signals for transmission.

9. 9. The method of claim 8, wherein the W data frames are carried by W optical signals, respectively; and any two of the W optical signals have different wavelengths; or The method, wherein the W optical signals all have the same wavelength, and the W optical signals are transmitted over W optical fibers, respectively.

10. 10. The method according to claim 8 or 9, wherein the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other; In the first polarization direction, the Q pilot symbols in the first data frame are generated by using a first target polynomial and a first seed; and in the second polarization direction, the Q pilot symbols in the first data frame are generated by using a first target polynomial and a second seed; and in the first polarization direction, Q pilot symbols in the second data frame are generated by using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated by using a second target polynomial and a fourth seed.

11. 11. The method of claim 10, wherein a first pilot symbol sequence in the first data frame is the same as a second pilot symbol sequence in the second data frame, the first pilot symbol sequence including Q pilot symbols in the first data frame, and the second pilot symbol sequence including Q pilot symbols in the second data frame.

12. 12. The method of claim 11, wherein the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

13. 11. The method of claim 10, wherein a first pilot symbol sequence in the first data frame is different from a second pilot symbol sequence in the second data frame, the first pilot symbol sequence including Q pilot symbols in the first data frame, and the second pilot symbol sequence including Q pilot symbols in the second data frame.

14. 14. The method of claim 13, wherein the first target polynomial is the same as the second target polynomial, and any two of the first seed, the second seed, the third seed, and the fourth seed are different from each other.

15. 14. The method of claim 13, wherein the first target polynomial is different from the second target polynomial.

16. 16. The method according to any one of claims 1 to 15, wherein the number of consecutive identical pilot symbols in a data frame in a given polarization direction is equal to or less than four.

17. 17. The method according to any one of claims 1 to 16, wherein in a certain polarization direction, the modulation format of the symbols in the data frame is 16QAM, and A=-1, 1, -3, 3, -√5, or √5.

18. 18. The method according to any one of claims 1 to 17, wherein in a certain polarization direction, the modulation format of the symbols in the data frame is QPSK and A=-1 or 1.

19. 1. A data transmission method comprising: generating a data frame, in a polarization direction, the data frame including N symbols, one pilot symbol at a fixed position for every M consecutive symbols among the N symbols, and M−1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1, the Q pilot symbols are generated by using a target polynomial and a seed, each pilot symbol is one of four complex numbers: −A−Aj, −A+Aj, A−Aj, and A+Aj, where A is a real number, the Q pilot symbols are DC balanced, and the difference between any two of the numbers of −A−Aj, −A+Aj, A−Aj, and A+Aj in the data frame is less than or equal to 2; and transmitting the data frame; A method comprising:

20. 20. The method of claim 19, In one polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 176] and the number of pilot symbols, which is -A+Aj, is [Number 177] and the number of pilot symbols A-Aj is [Number 178] and the number of pilot symbols A+Aj is [Number 179] is; or In one polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 180] and the number of pilot symbols, which is -A+Aj, is [Number 181] and the number of pilot symbols A-Aj is [Number 182] and the number of pilot symbols A+Aj is [Number 183] is; or In one polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 184] and the number of pilot symbols, which is -A+Aj, is [Number 185] and the number of pilot symbols A-Aj is [Number 186] and the number of pilot symbols A+Aj is [Number 187] is; or In one polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 188] and the number of pilot symbols, which is -A+Aj, is [Number 189] and the number of pilot symbols A-Aj is [Number 190] and the number of pilot symbols A+Aj is [Number 191] and [Number 192] is a method of rounding a positive real number a down to the nearest integer.

21. 21. The method of claim 19 or 20, wherein N=6144, M=64, Q=96, the target polynomial is x^9+x^8+x^5+x^4+1, a seed for the first polarization direction is 0x175, a seed for the second polarization direction is 0x03D, and the first polarization direction and the second polarization direction are orthogonal to each other.

22. 22. The method of claim 21, wherein the 96 pilot symbols in the first polarization direction are arranged in order as follows: A-Aj, A-Aj, A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A-Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, A-Aj, A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, -A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,- j, A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, A-Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, -A+Aj, A+A j, -A-Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, A+Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, and -A-Aj; and The 96 pilot symbols in the second wave direction are: A-Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A-A j, A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, -A+Aj, A+Aj, A-Aj, -A- Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, A-Aj, A -Aj, -A+Aj, A-Aj, A+Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, -A+Aj, A-Aj, -A-Aj, - A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A+A j, A+Aj, A-Aj, A-Aj, A+Aj, A+Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, A-Aj, A+Aj, A+Aj, and The method is A+Aj.

23. 21. The method of claim 20, In a first polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 193] and the number of pilot symbols, which is -A+Aj, is [Number 194] and the number of pilot symbols A-Aj is [Number 195] and the number of pilot symbols A+Aj is [Number 196] and and in the second polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 197] and the number of pilot symbols, which is -A+Aj, is [Number 198] and the number of pilot symbols A-Aj is [Number 199] and the number of pilot symbols A+Aj is [Number 200] is; or In a first polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 201] and the number of pilot symbols, which is -A+Aj, is [Number 202] and the number of pilot symbols A-Aj is [Number 203] and the number of pilot symbols A+Aj is [Number 204] and and in the second polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 205] and the number of pilot symbols, which is -A+Aj, is [Number 206] and the number of pilot symbols A-Aj is [Number 207] and the number of pilot symbols A+Aj is [Number 208] and [Number 209] represents a positive real number a rounded down to the nearest integer, and the first polarization direction and the second polarization direction are orthogonal to each other.

24. 24. The method of claim 19, 20, or 23, wherein N=6144, M=64, and Q=96; The 96 pilot symbols in the first polarization direction are, in order: A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, A- Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A -Aj, -A-Aj, A-Aj, -A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A+ Aj, A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+ Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, - A-Aj, -A-Aj, A-Aj, A+Aj, A+Aj, A+Aj, A+Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A +Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A -Aj, A+Aj, A+Aj, A-Aj, A+Aj, A-Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, and A+Aj; and The 96 pilot symbols in the second polarization direction are, in order: A - Aj, A - Aj, A - Aj, -A - Aj, A - Aj, -A + Aj, A - Aj, A - Aj, -A + Aj, A - Aj, A + Aj, -A + Aj, A - Aj, -A - Aj, -A - Aj, -A + Aj, -A + Aj, -A - Aj, A + Aj, A - Aj, A - Aj, A - Aj, -A + Aj, A - Aj, -A + Aj, -A + Aj, A + Aj, A - Aj, A + Aj, A + Aj, A + Aj, -A + Aj, A - Aj, -A + Aj, A - Aj, -A + Aj, A + Aj, A + Aj, A + Aj, -A + Aj, -A - Aj, -A + Aj, A + Aj, A + Aj, -A - Aj, -A + Aj, -A + Aj, -A - Aj, -A + Aj, A - Aj, A + Aj, -A - Aj, A - Aj, -A - Aj, A + Aj, -A - Aj, A - Aj, -A + Aj, A + Aj, -A - Aj, -A + Aj, -A - Aj, -A - Aj, -A + Aj, -A + Aj, A - Aj, A + Aj, A + Aj, -A - Aj, -A + Aj, A + Aj, -A - Aj, -A - Aj, -A - Aj, -A - Aj, A - Aj, -A - Aj, -A + Aj, A - Aj, A + Aj, A - Aj, A - Aj, -A + Aj, -A + Aj, A + Aj, -A - Aj, A + Aj, A - Aj, -A + Aj, A - Aj, -A - Aj, A + Aj, A + Aj, -A - Aj, -A - Aj, and A + Aj, wherein the first polarization direction and the second polarization direction are orthogonal to each other, a method.

25. In the method according to claim 19, 20, or 23, N = 6144, M = 64, Q = 96; The 96 pilot symbols in the first polarization direction are, in order: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,- j, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, and -A+Aj; and The 96 pilot symbols in the second wave direction are: A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A- Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, A+Aj, -A +Aj, -A-Aj, A+Aj, A+Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A -Aj, A+Aj, -A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, A-Aj, -A+Aj, A+Aj, A -Aj, A+Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, A+Aj, A+Aj, A+Aj, A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, and A+Aj, and the first polarization direction and the second polarization direction are orthogonal to each other.

26. 26. The method of any one of claims 19 to 25, wherein the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried in multiple optical signals for transmission.

27. 27. The method of claim 26, wherein the W data frames are carried in W optical signals, respectively; and any two of the W optical signals have different wavelengths; or The method, wherein the W optical signals all have the same wavelength, and the W optical signals are transmitted over W optical fibers, respectively.

28. 28. The method of claim 26 or 27, wherein the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other; In the first polarization direction, the Q pilot symbols in the first data frame are generated by using a first target polynomial and a first seed; and in the second polarization direction, the Q pilot symbols in the first data frame are generated by using a first target polynomial and a second seed; and in the first polarization direction, Q pilot symbols in the second data frame are generated by using a second target polynomial and a third seed; and in the second polarization direction, Q pilot symbols in the second data frame are generated by using a second target polynomial and a fourth seed.

29. 30. The method of claim 28, wherein a first pilot symbol sequence in the first data frame is the same as a second pilot symbol sequence in the second data frame, the first pilot symbol sequence including Q pilot symbols in the first data frame, and the second pilot symbol sequence including Q pilot symbols in the second data frame.

30. 30. The method of claim 29, wherein the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

31. 30. The method of claim 28, wherein a first pilot symbol sequence in the first data frame is different from a second pilot symbol sequence in the second data frame, the first pilot symbol sequence including Q pilot symbols in the first data frame, and the second pilot symbol sequence including Q pilot symbols in the second data frame.

32. 32. The method of claim 31 , wherein the first target polynomial is the same as the second target polynomial, and any two of the first seed, the second seed, the third seed, and the fourth seed are different from each other.

33. 32. The method of claim 31, wherein the first target polynomial is different from the second target polynomial.

34. 34. The method according to any one of claims 19 to 33, wherein the number of consecutive identical pilot symbols in a data frame in a given polarization direction is equal to or less than four.

35. 35. The method according to any one of claims 19 to 34, wherein in a certain polarization direction, the modulation format of the symbols in the data frame is 16QAM, and A=-1, 1, -3, 3, -√5, or √5.

36. 36. The method according to any one of claims 19 to 35, wherein in a certain polarization direction, the modulation format of the symbols in the data frame is QPSK and A=-1 or 1.

37. 1. A data transmission method comprising: receiving a data frame, in a polarization direction, the data frame including N symbols, one pilot symbol at a fixed position for every M consecutive symbols among the N symbols, and M−1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1, the Q pilot symbols are generated using a target polynomial and a seed, each pilot symbol being one of four complex numbers: −A−Aj, −A+Aj, A−Aj, and A+Aj, where A is a real number, the Q pilot symbols are DC balanced, the degree of the target polynomial is less than or equal to 10, and the number of terms of the target polynomial is greater than or equal to 2 and less than or equal to 8; and processing the data frames; A method comprising:

38. 1. A data transmission method comprising: receiving a data frame, in a polarization direction, the data frame including N symbols, one pilot symbol at a fixed position for every M consecutive symbols among the N symbols, and M−1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1, the Q pilot symbols are generated by using a target polynomial and a seed, each pilot symbol is one of four complex numbers: −A−Aj, −A+Aj, A−Aj, and A+Aj, where A is a real number, the Q pilot symbols are DC balanced, and the difference between any two of the numbers of −A−Aj, −A+Aj, A−Aj, and A+Aj in the data frame is less than or equal to 2; and processing the data frames; A method comprising:

39. A data transmission device including a processing unit and a sending unit: the processing unit is configured to generate a data frame, in a polarization direction, the data frame including N symbols, one pilot symbol at a fixed position for every M consecutive symbols among the N symbols, and M−1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1, the Q pilot symbols are generated by using a target polynomial and a seed, each pilot symbol being one of four complex numbers: −A−Aj, −A+Aj, A−Aj, and A+Aj, where A is a real number, the Q pilot symbols are DC balanced, the degree of the target polynomial is less than or equal to 10, and the number of terms of the target polynomial is greater than or equal to 2 and less than or equal to 8; and The transmitting unit is configured to transmit the data frame.

40. 40. The data transmission device of claim 39, wherein the target polynomial is: x^9+x^4+x^3+x+1; x^9+x^5+x^4+x+1; x^9+x^8+x^5+x^4+1; x^9+x^8+x^6+x^5+1; x^10+x^4+x^3+x+1; x^10+x^5+x^2+x+1; x^10+x^8+x^5+x+1; x^10+x^9+x^4+x+1; x^10+x^9+x^5+x^2+1; x^10+x^9+x^6+x+1; x^10+x^9+x^7+x^6+1; x^10+x^9+x^8+x^5+1; x^10+x^8+x^6+x^5+x^3+x+1; x^10+x^8+x^7+x^3+x^2+x+1; x^10+x^8+x^7+x^6+x^2+x+1; x^10+x^9+x^7+x^5+x^4+x^2+1; x^10+x^9+x^8+x^4+x^3+x^2+1; or x^10+x^9+x^8+x^7+x^3+x^2+1 A data transmission device, one of the

41. 41. A data transmission device according to claim 39 or 40, wherein each pilot symbol is located at the beginning of M consecutive symbols in which the pilot symbol is located.

42. 42. A data transmission device according to any one of claims 39 to 41, wherein a sequence containing Q pilot symbols in a first polarization direction is different from a sequence containing Q pilot symbols in a second polarization direction, and the first polarization direction and the second polarization direction are orthogonal to each other.

43. 43. The data transmission device according to claim 39, wherein N=6144, M=64, and Q=96, and the correspondence relationship between the target polynomial, the seed in the first polarization direction, and the seed in the second polarization direction is as follows: the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x002, and a seed in the second polarization direction: 0x115; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x002, and a seed in the second polarization direction: 0x02B; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x049, and a seed in the second polarization direction: 0x115; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x049, and a seed in the second polarization direction: 0x02B; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x115, and a seed in the second polarization direction: 0x08D; the target polynomial: x^9+x^4+x^3+x+1, a seed in the first polarization direction: 0x08D, and a seed in the second polarization direction: 0x02B; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x098, and a seed in the second polarization direction: 0x0FE; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x098, and a seed in the second polarization direction: 0x0BF; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x098, and a seed in the second polarization direction: 0x17F; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x14C, and a seed in the second polarization direction: 0x0FE; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x14C, and a seed in the second polarization direction: 0x0BF; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x14C, and a seed in the second polarization direction: 0x17F; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x0A6, and a seed in the second polarization direction: 0x0FE; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x0A6, and a seed in the second polarization direction: 0x0BF; the target polynomial: x^9+x^5+x^4+x+1, a seed in the first polarization direction: 0x0A6, and a seed in the second polarization direction: 0x17F; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x1D4, and a seed in the second polarization direction: 0x11E; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x1D4, and a seed in the second polarization direction: 0x03D; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x1D4, and a seed in the second polarization direction: 0x08F; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x0EA, and a seed in the second polarization direction: 0x11E; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x0EA, and a seed in the second polarization direction: 0x03D; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x0EA, and a seed in the second polarization direction: 0x08F; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x11E, and a seed in the second polarization direction: 0x175; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x175, and a seed in the second polarization direction: 0x03D; the target polynomial: x^9+x^8+x^5+x^4+1, a seed in the first polarization direction: 0x175, and a seed in the second polarization direction: 0x08F; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x16A, and a seed in the second polarization direction: 0x1E1; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x16A, and a seed in the second polarization direction: 0x1C3; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x1E1, and a seed in the second polarization direction: 0x069; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x1E1, and a seed in the second polarization direction: 0x113; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x069, and a seed in the second polarization direction: 0x1C3; the target polynomial: x^9+x^8+x^6+x^5+1, a seed in the first polarization direction: 0x1C3, and a seed in the second polarization direction: 0x113; the target polynomial: x^10+x^4+x^3+x+1, a seed in the first polarization direction: 0x0E6, and a seed in the second polarization direction: 0x36E; the target polynomial: x^10+x^5+x^2+x+1, a seed in the first polarization direction: 0x3DC, and a seed in the second polarization direction: 0x36A; the target polynomial: x^10+x^5+x^2+x+1, a seed in the first polarization direction: 0x36A, and a seed in the second polarization direction: 0x35E; the target polynomial: x^10+x^5+x^2+x+1, a seed in the first polarization direction: 0x36A, and a seed in the second polarization direction: 0x1AF; the target polynomial: x^10+x^8+x^5+x+1, a seed in the first polarization direction: 0x1FD, and a seed in the second polarization direction: 0x3A7; the target polynomial: x^10+x^9+x^4+x+1, a seed in the first polarization direction: 0x12A, and a seed in the second polarization direction: 0x039; the target polynomial: x^10+x^9+x^4+x+1, a seed in the first polarization direction: 0x12A, and a seed in the second polarization direction: 0x107; the target polynomial: x^10+x^9+x^4+x+1, a seed in the first polarization direction: 0x039, and a seed in the second polarization direction: 0x295; the target polynomial: x^10+x^9+x^4+x+1, a seed in the first polarization direction: 0x295, and a seed in the second polarization direction: 0x107; the target polynomial: x^10+x^9+x^5+x^2+1, a seed in the first polarization direction: 0x26A, and a seed in the second polarization direction: 0x03A; the target polynomial: x^10+x^9+x^6+x+1, a seed in the first polarization direction: 0x1A2, and a seed in the second polarization direction: 0x379; the target polynomial: x^10+x^9+x^6+x+1, a seed in the first polarization direction: 0x1A2, and a seed in the second polarization direction: 0x3EF; the target polynomial: x^10+x^9+x^6+x+1, a seed in the first polarization direction: 0x2D1, and a seed in the second polarization direction: 0x379; the target polynomial: x^10+x^9+x^6+x+1, a seed in the first polarization direction: 0x2D1, and a seed in the second polarization direction: 0x3EF; the target polynomial: x^10+x^9+x^7+x^6+1, a seed in the first polarization direction: 0x3CC, and a seed in the second polarization direction: 0x1E2; the target polynomial: x^10+x^9+x^8+x^5+1, a seed in the first polarization direction: 0x170, and a seed in the second polarization direction: 0x14D; the target polynomial: x^10+x^9+x^8+x^5+1, a seed in the first polarization direction: 0x0B8, and a seed in the second polarization direction: 0x14D; the target polynomial: x^10+x^9+x^8+x^5+1, a seed in the first polarization direction: 0x299, and a seed in the second polarization direction: 0x14D; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x354, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x17C, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x1AA, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x06A, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x3E6, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2A9, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2F9, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x0D5, and a seed in the second polarization direction: 0x2AD; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2AD, and a seed in the second polarization direction: 0x1F3; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2AD, and a seed in the second polarization direction: 0x14B; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2AD, and a seed in the second polarization direction: 0x297; the target polynomial: x^10+x^8+x^6+x^5+x^3+x+1, a seed in the first polarization direction: 0x2AD, and a seed in the second polarization direction: 0x12F; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x3AC; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x1D6; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x075; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x0ED; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x320, and a seed in the second polarization direction: 0x0EB; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x0D4, and a seed in the second polarization direction: 0x3AC; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x0D4, and a seed in the second polarization direction: 0x1D6; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x0D4, and a seed in the second polarization direction: 0x075; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x0D4, and a seed in the second polarization direction: 0x0EB; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x3AC, and a seed in the second polarization direction: 0x01A; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x01A, and a seed in the second polarization direction: 0x1D6; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x01A, and a seed in the second polarization direction: 0x075; the target polynomial: x^10+x^8+x^7+x^3+x^2+x+1, a seed in the first polarization direction: 0x01A, and a seed in the second polarization direction: 0x0EB; the target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, a seed in the first polarization direction: 0x1B0, and a seed in the second polarization direction: 0x3F4; the target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, a seed in the first polarization direction: 0x1B0, and a seed in the second polarization direction: 0x1FA; the target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, a seed in the first polarization direction: 0x3F4, and a seed in the second polarization direction: 0x13D; the target polynomial: x^10+x^8+x^7+x^6+x^2+x+1, a seed in the first polarization direction: 0x1FA, and a seed in the second polarization direction: 0x13D; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x35C, and a seed in the second polarization direction: 0x2EE; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x0DC, and a seed in the second polarization direction: 0x2EE; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x33A, and a seed in the second polarization direction: 0x2EE; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x26E, and a seed in the second polarization direction: 0x2EE; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x2B9; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x1B9; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x275; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x39D; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x173; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x0EB; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x39B; the target polynomial: x^10+x^9+x^7+x^5+x^4+x^2+1, a seed in the first polarization direction: 0x2EE, and a seed in the second polarization direction: 0x337; the target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, a seed in the first polarization direction: 0x0C6, and a seed in the second polarization direction: 0x157; the target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, a seed in the first polarization direction: 0x0C6, and a seed in the second polarization direction: 0x2D7; the target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, a seed in the first polarization direction: 0x263, and a seed in the second polarization direction: 0x157; the target polynomial: x^10+x^9+x^8+x^4+x^3+x^2+1, a seed in the first polarization direction: 0x263, and a seed in the second polarization direction: 0x2D7; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x130; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x298; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x34C; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x261; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x350, and a seed in the second polarization direction: 0x01F; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x130, and a seed in the second polarization direction: 0x014; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x130, and a seed in the second polarization direction: 0x282; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x298, and a seed in the second polarization direction: 0x014; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x298, and a seed in the second polarization direction: 0x282; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x014, and a seed in the second polarization direction: 0x34C; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed in the first polarization direction: 0x014, and a seed in the second polarization direction: 0x261; the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed for the first polarization direction: 0x34C, and a seed for the second polarization direction: 0x282; or the target polynomial: x^10+x^9+x^8+x^7+x^3+x^2+1, a seed for the first polarization direction: 0x282, and a seed for the second polarization direction: 0x261 A data transmission device, one of the

44. 44. The data transmission device according to claim 39, wherein N=6144, M=64, and Q=96, the target polynomial is x^9+x^4+x^3+x+1, a seed in the first polarization direction is 0x049, a seed in the second polarization direction is 0x115, and the first polarization direction and the second polarization direction are orthogonal to each other; The 96 pilot symbols in the first polarization direction are, in order: A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A-Aj,-A-Aj,A+Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,A-Aj,-A+Aj,A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+ -Aj,-A-Aj,A-Aj,-A-Aj,A-Aj,A-Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,A+Aj,-A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,-A-Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A+Aj,-A+ Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, A+Aj, A+Aj, A+Aj, A+Aj, A+Aj, A+Aj, A+Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A +Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, and A+Aj; and The 96 pilot symbols in the second wave direction are: A-Aj, A-Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A -Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A-Aj, A-Aj, A-Aj, -A+Aj, A-Aj, - A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A +Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, -A-Aj , -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, A-Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, A+Aj, -A- Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, A-Aj, -A+Aj, -A +Aj, A+Aj, -A-Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, and A data transmission device that is A+Aj.

45. 44. The data transmission device according to claim 39, wherein N=6144, M=64, and Q=96, the target polynomial is x^10+x^9+x^4+x+1, the seed in the first polarization direction is 0x12A, the seed in the second polarization direction is 0x039, and the first polarization direction and the second polarization direction are orthogonal to each other; The 96 pilot symbols in the first polarization direction are, in order: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,- j, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, and -A+Aj; and The 96 pilot symbols in the second wave direction are: A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A- Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, A+Aj, -A +Aj, -A-Aj, A+Aj, A+Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, A-Aj, -A+Aj, A+Aj, A -Aj, A+Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, A+Aj, A+Aj, A-Aj, -A+Aj, -A+Aj, -A- Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, and A data transmission device that is A+Aj.

46. 46. ​​A data transmission device according to any one of claims 39 to 45, wherein the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried on a plurality of optical signals for transmission.

47. 47. The data transmission apparatus of claim 46, wherein the W data frames are carried by W optical signals, respectively; and any two of the W optical signals have different wavelengths; or A data transmission device, wherein the W optical signals all have the same wavelength, and the W optical signals are transmitted via W optical fibers, respectively.

48. 48. The data transmission device according to claim 46 or 47, wherein the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other; In the first polarization direction, the Q pilot symbols in the first data frame are generated by using a first target polynomial and a first seed; and in the second polarization direction, the Q pilot symbols in the first data frame are generated by using a first target polynomial and a second seed; and in the first polarization direction, the Q pilot symbols in the second data frame are generated by using a second target polynomial and a third seed; and in the second polarization direction, the Q pilot symbols in the second data frame are generated by using a second target polynomial and a fourth seed.

49. 49. The data transmission device of claim 48, wherein a first pilot symbol sequence in the first data frame is the same as a second pilot symbol sequence in the second data frame, the first pilot symbol sequence including Q pilot symbols in the first data frame, and the second pilot symbol sequence including Q pilot symbols in the second data frame.

50. 50. The data transmission device of claim 49, wherein the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

51. 49. The data transmission apparatus of claim 48, wherein a first pilot symbol sequence in the first data frame is different from a second pilot symbol sequence in the second data frame, the first pilot symbol sequence including Q pilot symbols in the first data frame, and the second pilot symbol sequence including Q pilot symbols in the second data frame.

52. 52. The data transmission device of claim 51, wherein the first target polynomial is the same as the second target polynomial, and any two of the first seed, the second seed, the third seed, and the fourth seed are different from each other.

53. 52. The data transmission device of claim 51, wherein the first target polynomial is different from the second target polynomial.

54. 54. A data transmission device according to any one of claims 39 to 53, wherein the number of consecutive identical pilot symbols in a data frame in a certain polarization direction is four or less.

55. 55. The data transmission device according to any one of claims 39 to 54, wherein in a certain polarization direction, the modulation format of the symbols in the data frame is 16QAM, and A=-1, 1, -3, 3, -√5, or √5.

56. 56. A data transmission device according to any one of claims 39 to 55, wherein in a certain polarization direction, the modulation format of the symbols in the data frame is QPSK, and A=-1 or 1.

57. 1. A data transmission device including a processing unit and a sending unit: the processing unit is configured to generate a data frame, in a polarization direction, the data frame including N symbols, one pilot symbol at a fixed position for every M consecutive symbols among the N symbols, and M−1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1, the Q pilot symbols are generated by using a target polynomial and a seed, each pilot symbol is one of four complex numbers: −A−Aj, −A+Aj, A−Aj, and A+Aj, where A is a real number, the Q pilot symbols are DC balanced, and the difference between any two of the numbers of −A−Aj, −A+Aj, A−Aj, and A+Aj in the data frame, respectively, is less than or equal to 2; and The transmitting unit is configured to transmit the data frame.

58. 58. The data transmission device according to claim 57, In one polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 210] and the number of pilot symbols, which is -A+Aj, is [Number 211] and the number of pilot symbols A-Aj is [Number 212] and the number of pilot symbols A+Aj is [Number 213] is; or In one polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 214] and the number of pilot symbols, which is -A+Aj, is [Number 215] and the number of pilot symbols A-Aj is [Number 216] and the number of pilot symbols A+Aj is [Number 217] is; or In one polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 218] and the number of pilot symbols, which is -A+Aj, is [Number 219] and the number of pilot symbols A-Aj is [Number 220] and the number of pilot symbols A+Aj is [Number 221] is; or In one polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 222] and the number of pilot symbols, which is -A+Aj, is [Number 223] and the number of pilot symbols A-Aj is [Number 224] and the number of pilot symbols A+Aj is [Number 225] and [Number 226] represents a positive real number a rounded down to the nearest integer.

59. A data transmission device as described in claim 57 or 58, wherein N=6144, M=64, Q=96, the target polynomial is x^9+x^8+x^5+x^4+1, the seed in the first polarization direction is 0x175, the seed in the second polarization direction is 0x03D, and the first polarization direction and the second polarization direction are orthogonal to each other.

60. 60. The data transmission device of claim 59, wherein the 96 pilot symbols in the first polarization direction are arranged in order as follows: A-Aj, A-Aj, A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A-Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, A-Aj, A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, -A+Aj,-A-Aj,A+Aj,A+Aj,A+Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,-A+Aj,-A-Aj,-A-Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A+Aj,A+Aj,- j, A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, A-Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, -A+Aj, A+A j, -A-Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, A+Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, and -A-Aj; and The 96 pilot symbols in the second wave direction are: A-Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A-A j, A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, -A+Aj, A+Aj, A-Aj, -A- Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, A-Aj, A -Aj, -A+Aj, A-Aj, A+Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, -A+Aj, A-Aj, -A-Aj, - A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A+A j, A+Aj, A-Aj, A-Aj, A+Aj, A+Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, A-Aj, A+Aj, A+Aj, and A data transmission device that is A+Aj.

61. 59. The data transmission device according to claim 58, In a first polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 227] and the number of pilot symbols, which is -A+Aj, is [Number 228] and the number of pilot symbols A-Aj is [Number 229] and the number of pilot symbols A+Aj is [Number 230] and and in the second polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 231] and the number of pilot symbols, which is -A+Aj, is [Number 232] and the number of pilot symbols A-Aj is [Number 233] and the number of pilot symbols A+Aj is [Number 234] is; or In a first polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 235] and the number of pilot symbols, which is -A+Aj, is [Number 236] and the number of pilot symbols A-Aj is [Number 237] and the number of pilot symbols A+Aj is [Number 238] and and in the second polarization direction, in the data frame: The number of pilot symbols is -A-Aj. [Number 239] and the number of pilot symbols, which is -A+Aj, is [Number 240] and the number of pilot symbols A-Aj is [Number 241] and the number of pilot symbols A+Aj is [Number 242] and [Number 243] represents rounding down a positive real number a to the nearest integer, and the first polarization direction and the second polarization direction are orthogonal to each other.

62. 62. The data transmission device of claim 57, 58, or 61, wherein N=6144, M=64, and Q=96; The 96 pilot symbols in the first polarization direction are, in order: A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, A- Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A -Aj, -A-Aj, A-Aj, -A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A+ Aj, A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+ Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, - A-Aj, -A-Aj, A-Aj, A+Aj, A+Aj, A+Aj, A+Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A +Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A -Aj, A+Aj, A+Aj, A-Aj, A+Aj, A-Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, and A+Aj; and The 96 pilot symbols in the second polarization direction are, in order: A - Aj, A - Aj, A - Aj, -A - Aj, A - Aj, -A + Aj, A - Aj, A - Aj, -A + Aj, A - Aj, A + Aj, -A + Aj, A - Aj, -A - Aj, -A - Aj, -A + Aj, -A + Aj, -A - Aj, A + Aj, A - Aj, A - Aj, A - Aj, -A + Aj, A - Aj, -A + Aj, -A + Aj, A + Aj, A - Aj, A + Aj, A + Aj, A + Aj, -A + Aj, A - Aj, -A + Aj, A - Aj, -A + Aj, A + Aj, A + Aj, A + Aj, -A + Aj, -A - Aj, -A + Aj, A + Aj, A + Aj, -A - Aj, -A + Aj, -A + Aj, -A - Aj, -A + Aj, A - Aj, A + Aj, -A - Aj, A - Aj, -A - Aj, A + Aj, -A - Aj, A - Aj, -A + Aj, A + Aj, -A - Aj, -A + Aj, -A - Aj, -A - Aj, -A + Aj, -A + Aj, A - Aj, A + Aj, A + Aj, -A - Aj, -A + Aj, A + Aj, -A - Aj, -A - Aj, -A - Aj, -A - Aj, A - Aj, -A - Aj, -A + Aj, A - Aj, A + Aj, A - Aj, A - Aj, -A + Aj, -A + Aj, A + Aj, -A - Aj, A + Aj, A - Aj, -A + Aj, A - Aj, -A - Aj, A + Aj, A + Aj, -A - Aj, -A - Aj, and A + Aj, and the first polarization direction and the second polarization direction are orthogonal to each other, a data transmission device.

63. In the data transmission device according to claim 57, 58, or 61, N = 6144, M = 64, Q = 96; The 96 pilot symbols in the first polarization direction are, in order: -A+Aj,-A+Aj,-A+Aj,-A-Aj,A-Aj,A+Aj,-A+Aj,A-Aj,A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj,-A+Aj,-A-Aj,-A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, A+Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A-Aj,A+Aj,A-Aj,A+Aj,A-Aj,A-Aj,-A-Aj,A+Aj,A-Aj,-A-Aj,A+Aj,-A-Aj,A-Aj,-A+Aj,A-Aj,A-Aj,- j, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, and -A+Aj; and The 96 pilot symbols in the second wave direction are: A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A- Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, A+Aj, -A +Aj, -A-Aj, A+Aj, A+Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A -Aj,A+Aj,-A-Aj,-A+Aj,-A-Aj,A-Aj,-A-Aj,-A-Aj,-A+Aj,A-Aj,A+Aj,A-Aj, A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, A-Aj, -A+Aj, A+Aj, A -Aj, A+Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, A+Aj, A+Aj, A+Aj, A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, A-Aj, A+Aj, and A+Aj, and the first polarization direction and the second polarization direction are orthogonal to each other.

64. 64. A data transmission device according to any one of claims 57 to 63, wherein the number of data frames is W, where W is an integer greater than 1, and the W data frames are carried on a plurality of optical signals for transmission.

65. 65. The data transmission apparatus of claim 64, wherein the W data frames are carried by W optical signals, respectively; and any two of the W optical signals have different wavelengths; or A data transmission device, wherein the W optical signals all have the same wavelength, and the W optical signals are transmitted via W optical fibers, respectively.

66. 66. The data transmission device according to claim 64 or 65, wherein the W data frames include a first data frame and a second data frame, and the first polarization direction and the second polarization direction are orthogonal to each other; In the first polarization direction, the Q pilot symbols in the first data frame are generated by using a first target polynomial and a first seed; and in the second polarization direction, the Q pilot symbols in the first data frame are generated by using a first target polynomial and a second seed; and in the first polarization direction, the Q pilot symbols in the second data frame are generated by using a second target polynomial and a third seed; and in the second polarization direction, the Q pilot symbols in the second data frame are generated by using a second target polynomial and a fourth seed.

67. 67. The data transmission device of claim 66, wherein a first pilot symbol sequence in the first data frame is the same as a second pilot symbol sequence in the second data frame, the first pilot symbol sequence including Q pilot symbols in the first data frame, and the second pilot symbol sequence including Q pilot symbols in the second data frame.

68. 68. The data transmission device of claim 67, wherein the first target polynomial is the same as the second target polynomial, the first seed is the same as the third seed, the second seed is the same as the fourth seed, the first seed is different from the second seed, and the third seed is different from the fourth seed.

69. 67. The data transmission apparatus of claim 66, wherein a first pilot symbol sequence in the first data frame is different from a second pilot symbol sequence in the second data frame, the first pilot symbol sequence including Q pilot symbols in the first data frame, and the second pilot symbol sequence including Q pilot symbols in the second data frame.

70. 70. The data transmission device of claim 69, wherein the first target polynomial is the same as the second target polynomial, and any two of the first seed, the second seed, the third seed, and the fourth seed are different from each other.

71. 70. The data transmission device of claim 69, wherein the first target polynomial is different from the second target polynomial.

72. 72. A data transmission device according to any one of claims 57 to 71, wherein the number of consecutive identical pilot symbols in the data frame in a certain polarization direction is four or less.

73. 73. The data transmission device according to any one of claims 57 to 72, wherein in a certain polarization direction, the modulation format of the symbols in the data frame is 16QAM, and A=-1, 1, -3, 3, -√5, or √5.

74. 73. A data transmission device according to any one of claims 57 to 72, wherein in a certain polarization direction, the modulation format of the symbols in the data frame is QPSK, and A=-1 or 1.

75. 1. A data transmission device including a receiving unit and a processing unit: the receiving unit is configured to receive a data frame, in a polarization direction, the data frame including N symbols, one pilot symbol at a fixed position for every M consecutive symbols among the N symbols and M−1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1, the Q pilot symbols are generated by using a target polynomial and a seed, each pilot symbol being one of four complex numbers: −A−Aj, −A+Aj, A−Aj, and A+Aj, where A is a real number, the Q pilot symbols are DC balanced, the degree of the target polynomial is less than or equal to 10, and the number of terms of the target polynomial is greater than or equal to 2 and less than or equal to 8; and The processing unit is configured to process the data frames.

76. 1. A data transmission device including a receiving unit and a processing unit: the receiving unit is configured to receive a data frame, in a polarization direction, the data frame including N symbols, one pilot symbol at a fixed position for every M consecutive symbols within the N symbols, and M−1 payload symbols, where N=M×Q, Q is an even number, and M is an integer greater than or equal to 1, the Q pilot symbols are generated by using a target polynomial and a seed, each pilot symbol is one of four complex numbers: −A−Aj, −A+Aj, A−Aj, and A+Aj, where A is a real number, the Q pilot symbols are DC balanced, and the difference between any two of the numbers of pilot symbols, which are −A−Aj, −A+Aj, A−Aj, and A+Aj, respectively, in the data frame is less than or equal to 2; and The processing unit is configured to process the data frames.

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