Data transmission method, device and system

Abstract

Disclosed in embodiments of the present application are a data transmission method, device and system. In one polarization direction, a data frame acquired by a sending end comprises N symbols, and every M consecutive symbols among the N symbols include one pilot symbol and M-1 payload symbols, wherein N=M×D; D is an even number; M is an integer greater than 1; the value of at least one pilot symbol among D pilot symbols is one of -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j; the value of at least one pilot symbol among the D pilot symbols is one of -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j; both A1 and A2 are real numbers not equal to 0; A1 is smaller than A2; and j represents an imaginary unit. It can be seen that in one polarization direction, some of the values of the D pilot symbols in the data frame are in an inner circle of a constellation diagram (for example, -A1-A1j, -A1+A1j, A1-A1j, or A1+A1j), and the remaining values are in an outer cycle of the constellation diagram (for example, -A2-A2j, -A2+A2j, A2-A2j, or A2+A2j), such that the peak-to-average power ratio and the cost of transmission performance of the D pilot symbols is relatively low.

Description

A data transmission method, apparatus and system

[0001] This application claims priority to Chinese Patent Application No. 202410783063.2, filed with the State Intellectual Property Office of China on June 17, 2024, entitled "A Data Transmission Method, Apparatus and System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a data transmission method, apparatus and system. Background Technology

[0003] Driven by 5G, cloud computing, big data, and artificial intelligence, high-speed optical transmission networks are developing towards higher capacity, packetization, and intelligence. Coherent optical communication systems utilize the amplitude, phase, polarization, or frequency of light waves to carry information. To combat optical signal distortion caused by dispersion, polarization-dependent impairments, noise, nonlinear effects, and other factors during transmission and to maintain long-distance transmission, coherent optical communication systems typically incorporate designed fixed symbol sequences into the transmitted symbol sequence to facilitate the receiver's recovery of the transmitted symbols.

[0004] In existing coherent optical transmission systems, the fixed symbol sequences used are mainly applied to scenarios with speeds of 400 gigabits per second (Gbps) and 800 Gbps, which cannot adapt to future scenarios with speeds of 1.2 terabit per second (Tbps) and above (including 1.2 Tbps and 1.6 Tbps). For example, in existing 800ZR or 800LR transmissions using dual-polarization 16-ary Quadrature Amplitude Modulation (DP-16QAM), the pilot sequence used comes from the outermost four symbols of the constellation diagram. While the pilot symbols have high sensitivity, they also have a high peak-to-average power ratio and high noise, resulting in a significant cost to actual transmission performance. This is a problem that urgently needs to be solved in the future. Summary of the Invention

[0005] This application provides a data transmission method, apparatus, and system that have a low cost in terms of actual transmission performance and are beneficial for improving the quality of signal recovery at the receiving end, and can be well applied to various coherent transmission scenarios.

[0006] In a first aspect, an embodiment of the present application provides a data transmission method, which is applied to a sending end. Specifically, the sending end obtains a data frame. Among them, in one polarization direction, the data frame includes N symbols. Among the N symbols, every consecutive M symbols include 1 pilot symbol and M-1 payload symbols. N = M×D, where D is an even number, M is an integer greater than 1. At least one of the D pilot symbols takes a value of one of -A1 - A1j, -A1 + A1j, A1 - A1j, and A1 + A1j. At least one of the D pilot symbols takes a value of one of -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j. Both A1 and A2 are non-zero real numbers, and A1 < A2. j represents the imaginary unit. Furthermore, the sending end sends the data frame. It should be noted that this method can also be applied to a specific module in the sending end. For example, the signal processor of the sending end. It should be understood that the module obtaining the data frame can be understood as the data frame generated by the module itself, or it can be understood as the data frame received by the module from the previous module. It should also be understood that the module sending the data frame can be understood as the module sending the data frame to the receiving end through the channel, or it can be understood as the module sending the data frame to the subsequent module.

[0007] In this embodiment, the complex numbers -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j, -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j are the constellation points corresponding to the symbol mapping adopted. It can be seen that in one polarization direction, the values of the D pilot symbols in the data frame are some in the inner circle of the constellation diagram (such as taking values of -A1 - A1j, -A1 + A1j, A1 - A1j, or A1 + A1j), and some in the outer circle of the constellation diagram (such as taking values of -A2 - A2j, -A2 + A2j, A2 - A2j, or A2 + A2j), so that the peak-to-average power ratio and the cost of transmission performance of the D pilot symbols are relatively low.

[0008] In some possible embodiments, the sum of the D pilot symbols is 0. That is to say, the sum of the real parts of the complex numbers corresponding to the D pilot symbols is 0, and the sum of the imaginary parts is also 0, so as to satisfy the DC balance, which is beneficial to improving the quality of the signal recovered by the receiving end.

[0009] In some possible embodiments, the D pilot symbols satisfy the DC balance, which is beneficial to improving the quality of the signal recovered by the receiving end.

[0010] In some possible implementations, the total number of pilot symbols with values ​​of -A1-A1j, -A1+A1j, A1-A1j, or A1+A1j among the D pilot symbols is D1, and the total number of pilot symbols with values ​​of -A2-A2j, -A2+A2j, A2-A2j, or A2+A2j among the D pilot symbols is D2, where D = D1 + D2, and both D1 and D2 are integers greater than 0. That is, in this implementation, each pilot symbol among the D pilot symbols takes one of eight complex numbers: -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, which better adapts to DP-16QAM scenarios.

[0011] In some possible implementations, the sum of the D1 pilot symbols is 0, the sum of the D2 pilot symbols is 0, and both D1 and D2 are even numbers. That is, the D1 pilot symbols corresponding to the inner circle of the constellation diagram satisfy DC balance, and the D2 pilot symbols corresponding to the outer circle of the constellation diagram also satisfy DC balance, so that all D pilot symbols satisfy DC balance, which is beneficial to improving the quality of signal recovery at the receiving end.

[0012] In some possible implementations, among the D1 pilot symbols, the number of pilot symbols with values ​​of -A1-A1j is d1, the number of pilot symbols with values ​​of -A1+A1j is d2, the number of pilot symbols with values ​​of A1-A1j is d3, and the number of pilot symbols with values ​​of A1+A1j is d4, where d1 = d4, d2 = d3, and D1 = d1 + d2 + d3 + d4. Among the D2 pilot symbols, the number of pilot symbols with values ​​of -A2-A2j is d5, the number of pilot symbols with values ​​of -A2+A2j is d6, the number of pilot symbols with values ​​of A2-A2j is d7, and the number of pilot symbols with values ​​of A2+A2j is d8, where d5 = d8, d6 = d7, and D2 = d5 + d6 + d7 + d8. This ensures that the sum of the D1 pilot symbols is 0 and the sum of the D2 pilot symbols is 0, so that all D pilot symbols satisfy DC balance, which is beneficial to improving the quality of the signal recovered by the receiver.

[0013] In some possible implementations, D1 ≥ D2. As an example, Probabilistic Constellation Shaping (PCS) is used to change the probability of constellation points appearing while keeping their positions constant, making them non-uniformly distributed, thereby improving system transmission performance. That is, the probability of a symbol being a constellation point symbol is different before framing. In this case, considering D1 > D2, the number of inner-circle constellation points in the constellation diagram among the D pilot symbols is greater than the number of outer-circle constellation points among the D pilot symbols, making the transmission performance cost caused by the D pilot symbols relatively low. As another example, conventional Quadrature Amplitude Modulation (QAM) modulation is used, where the probability of a symbol being a constellation point symbol is the same before framing. In this case, consider D1 = D2 = D / 2.

[0014] In some possible implementations, the number of pilot symbols with values ​​of -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j in the D1 pilot symbols differs from each other by less than or equal to 2, and the number of pilot symbols with values ​​of -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j in the D2 pilot symbols also differs from each other by less than or equal to 2. This effectively ensures that the number of pilot symbols with each value is nearly balanced, and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiving end.

[0015] In some possible implementations, D = 96, D1 = D / 2 = 48. Among the D1 pilot symbols, the number of pilot symbols with values ​​of -A1-A1j is d1, the number of pilot symbols with values ​​of -A1+A1j is d2, the number of pilot symbols with values ​​of A1-A1j is d3, and the number of pilot symbols with values ​​of A1+A1j is d4, where d1 = d4, d2 = d3, and D1 = d1 + d2 + d3 + d4. Alternatively, d1 = 11, d2 = 13, d3 = 13, d4 = 11; or d1 = 13, d2 = 11, d3 = 11, d4 = 13; or d1 = 12, d2 = 12, d3 = 12, d4 = 12. This effectively ensures that the number of pilot symbols for each value approaches balance and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0016] In some possible implementations, D = 96, D2 = D / 2 = 48. Among the D2 pilot symbols, the number of pilot symbols with values ​​of -A2-A2j is d5, the number of pilot symbols with values ​​of -A2+A2j is d6, the number of pilot symbols with values ​​of A2-A2j is d7, and the number of pilot symbols with values ​​of A2+A2j is d8, d5 = d8, d6 = d7, and D2 = d5 + d6 + d7 + d8. Alternatively, d5 = 11, d6 = 13, d7 = 13, d8 = 11; or d5 = 13, d6 = 11, d7 = 11, d8 = 13; or d5 = 12, d6 = 12, d7 = 12, d8 = 12. This effectively ensures that the number of pilot symbols for each value approaches balance and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiving end.

[0017] In some possible implementations, the data frame includes a total of 2×D pilot symbols in both polarization directions. Among these 2×D pilot symbols, the number of values ​​for -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j is D / 4. This effectively ensures a balanced number of pilot symbols, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0018] In some possible implementations, the D pilot symbols included in the data frame in the first polarization direction are different from the D pilot symbols included in the data frame in the second polarization direction, which facilitates the receiving end to distinguish the two polarization directions of the data frame.

[0019] In some possible implementations, the data frame employs a symbol mapping scheme of Dual-polarization 16-ary Quadrature Amplitude Modulation (DP-16QAM), where A1 / A2 = 1 / 3. Alternatively, the data frame employs a symbol mapping scheme of Dual-polarization 64-ary Quadrature Amplitude Modulation (DP-64QAM), where A1 / A2 = 1 / 3, or A1 / A2 = 1 / 5, or A1 / A2 = 1 / 7, or A1 / A2 = 3 / 5, or A1 / A2 = 3 / 7, or A1 / A2 = 5 / 7.

[0020] In some possible implementations, the D pilot symbols are generated from a target polynomial and a seed in one polarization direction, which simplifies hardware implementation.

[0021] In some possible implementations, the order of the target polynomial is less than or equal to 11, and the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8. When selecting a polynomial, the order and the number of non-zero terms should be minimized to reduce the complexity and power consumption of the pilot symbol generation structure. Given a target polynomial, there may not be a seed that results in good autocorrelation and cross-correlation between the target polynomial and the pilot symbol sequence determined by the seed. Therefore, the selection of the target polynomial is not merely about minimizing the order and the number of non-zero terms; it also requires considering whether a corresponding seed can be selected that results in good autocorrelation and cross-correlation characteristics of the generated pilot symbol sequence, including its real and imaginary parts, to improve the quality of the recovered signal at the receiving end.

[0022] In some possible implementations, the target polynomial is one of the following: x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1; x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1; x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1; x 11 +a 10 ×x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 + a1×x+1.

[0023] In some possible embodiments, in one polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed, and every consecutive 3 bits in the first bit sequence correspond to a pilot symbol. This embodiment is applicable to the scenario where dual-polarization symbol mapping is performed first and then framing is performed. It should be understood that there are a total of 8 combinations of the values of 3 bits, which can just correspond to the 8 values of the pilot symbol respectively, improving the feasibility of this solution.

[0024] In some possible embodiments, every consecutive 3 bits in the first bit sequence are respectively b 3t , b 3t+1 , b 3t+2 , where 0≤t<D, and every consecutive 3 bits in the first bit sequence and the corresponding pilot symbol satisfy the relationship shown in one of the following tables.

[0025] Table 1-1a

[0026] Table 1-2a

[0027] Table 1-3a

[0028] Table 1-4a

[0029] Table 1-5a

[0030] Table 1-6a

[0031] Table 1-7a

[0032] Table 1-8a

[0033] Table 1-9a

[0034] Table 1-10a

[0035] Table 1-11a

[0036] Table 1-12a

[0037] In some possible embodiments, in one polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed. Each consecutive 3 bits in the first bit sequence correspond to 4 bits, and the 4 bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping is performed.

[0038] In some possible embodiments, each consecutive 3 bits in the first bit sequence are respectively b 3t , b 3t+1 , b 3t+2 , where 0 ≤ t < D. Each consecutive 3 bits in the first bit sequence and the corresponding 4 bits satisfy the relationship shown in one of the following tables.

[0039] Table 1-1b

[0040] Table 1-2b

[0041] Table 1-3b

[0042] Table 1-4b

[0043] Table 1-5b

[0044] Table 1-6b

[0045] Table 1-7b

[0046] Table 1-8b

[0047] Table 1-9b

[0048] Table 1-10b

[0049] Table 1-11b

[0050] Table 1-12b

[0051] In some possible embodiments, D pilot symbols in the first polarization direction are generated by the target polynomial, the first seed, and the second seed, and D pilot symbols in the second polarization direction are generated by the target polynomial, the third seed, and the fourth seed. Among them, the target polynomial and the first seed are used to obtain the quadrant of each pilot symbol in the first polarization direction, and the target polynomial and the second seed are used to obtain the amplitude of each pilot symbol in the first polarization direction. The target polynomial and the third seed are used to obtain the quadrant of each pilot symbol in the second polarization direction, and the target polynomial and the fourth seed are used to obtain the amplitude of each pilot symbol in the second polarization direction.

[0052] In some possible embodiments, in the first polarization direction, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, and a third bit sequence including D bits is generated by the target polynomial and the second seed. Every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to one pilot symbol. In the second polarization direction, a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed, and a fifth bit sequence including D bits is generated by the target polynomial and the fourth seed. Every consecutive 2 bits in the fourth bit sequence and 1 bit in the fifth bit sequence, a total of 3 bits, correspond to one pilot symbol. This embodiment is applicable to the scenario where dual-polarization symbol mapping is performed first and then framing.

[0053] In some possible embodiments, every consecutive 2 bits in the second bit sequence or the fourth bit sequence are respectively b 2t and b 2t+1 , and 1 bit in the third bit sequence or the fifth bit sequence is s t , 0≤t<D. Every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence and the corresponding pilot symbol satisfy the relationship shown in one of the following tables, and every consecutive 2 bits in the fourth bit sequence and 1 bit in the fifth bit sequence and the corresponding pilot symbol satisfy the relationship shown in one of the following tables.

[0054] Table 2-1a

[0055] Table 2-2a

[0056] In some possible embodiments, on the first polarization direction, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, and a third bit sequence including D bits is generated by the target polynomial and the second seed. Every two consecutive bits in the second bit sequence and one bit in the third bit sequence, a total of three bits, correspond to four first bits, and the four first bits are symbol - mapped to obtain a pilot symbol. On the second polarization direction, a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed, and a fifth bit sequence including D bits is generated by the target polynomial and the fourth seed. Every two consecutive bits in the fourth bit sequence and one bit in the fifth bit sequence, a total of three bits, correspond to four second bits, and the four second bits are symbol - mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual - polarization symbol mapping is performed.

[0057] In some possible embodiments, every two consecutive bits in the second bit sequence or the fourth bit sequence are respectively b 2t and b 2t+1 , and one bit in the third bit sequence or the fifth bit sequence is s t , 0 ≤ t < D. Every two consecutive bits in the second bit sequence and one bit in the third bit sequence and the corresponding four bits satisfy the relationship shown in one of the following tables, and every two consecutive bits in the fourth bit sequence and one bit in the fifth bit sequence and the corresponding four bits satisfy the relationship shown in one of the following tables.

[0058] Table 2 - 1b

[0059] Table 2 - 2b

[0060] In some possible embodiments, D pilot symbols on the first polarization direction are generated by the target polynomial, the first seed, and the second seed, and D pilot symbols on the second polarization direction are generated by the target polynomial, the second seed, and the third seed. Among them, the target polynomial and the first seed are used to obtain the quadrant of each pilot symbol on the first polarization direction, the target polynomial and the third seed are used to obtain the quadrant of each pilot symbol on the second polarization direction, and the target polynomial and the second seed are used to obtain the amplitude of each pilot symbol on the first polarization direction and the amplitude of each pilot symbol on the second polarization direction.

[0061] In some possible embodiments, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed. In the first polarization direction, every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to a pilot symbol. In the second polarization direction, every consecutive 2 bits in the fourth bit sequence and the other 1 bit in the third bit sequence, a total of 3 bits, correspond to a pilot symbol. This embodiment is applicable to the scenario where double-polarization symbol mapping is performed first and then framing is carried out.

[0062] In some possible embodiments, every consecutive 2 bits in the second bit sequence are respectively and Every consecutive 2 bits in the fourth bit sequence are respectively and One bit in the third bit sequence is s 2t , and the other bit in the third bit sequence is s 2t+1 , where 0≤t<D. The relationship between every consecutive 2 bits in the second bit sequence and one bit in the third bit sequence and the corresponding pilot symbol satisfies one of the relationships shown in the following tables, and the relationship between every consecutive 2 bits in the fourth bit sequence and the other bit in the third bit sequence and the corresponding pilot symbol satisfies one of the relationships shown in the following tables.

[0063] Table 3-1a

[0064] Table 3-2a

[0065] In some possible embodiments, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed. In the first polarization direction, every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to 4 first bits, and the 4 first bits are symbol-mapped to obtain a pilot symbol. In the second polarization direction, every consecutive 2 bits in the fourth bit sequence and the other 1 bit in the third bit sequence, a total of 3 bits, correspond to 4 second bits, and the 4 second bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then double-polarization symbol mapping is carried out.

[0066] In some possible embodiments, every two consecutive bits in the second bit sequence are respectively and every two consecutive bits in the fourth bit sequence are respectively and One of the bits in the third bit sequence is s 2t , and the other bit in the third bit sequence is s 2t+1 , 0 ≤ t < D. Every two consecutive bits in the second bit sequence and one of the bits in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding 4 bits, and every two consecutive bits in the fourth bit sequence and the other bit in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding 4 bits.

[0067] Table 3-1b

[0068] Table 3-2b

[0069] In some possible embodiments, D = 96, and the 96 pilot symbols in the first polarization direction and the 96 pilot symbols in the second polarization direction of the data frame satisfy the relationship shown in the following table, where the value of pi is 1 or 3, the value of qi is 1 or 3, and 1 ≤ i ≤ 96.

[0070] Table 4

[0071] In some possible embodiments, N = 6144 and M = 64.

[0072] In some possible embodiments, each of the pilot symbols is located at the starting position of the consecutive M symbols where it is located.

[0073] Second aspect, embodiments of the present application provide a data transmission method, which is applied to a receiving end. Specifically, the receiving end receives a second data frame transmitted through a channel. It should be understood that the second data frame received by the receiving end is different from the first data frame transmitted by the sending end. The second data frame can be understood as a distorted signal affected by noise or other impairments in the channel. For the first data frame, in one polarization direction, the first data frame includes N symbols. Among the N symbols, every consecutive M symbols include 1 pilot symbol and M - 1 payload symbols. N = M × D, where D is an even number, M is an integer greater than 1, at least one of the D pilot symbols takes a value of one of -A1 - A1j, -A1 + A1j, A1 - A1j, and A1 + A1j, and at least one of the D pilot symbols takes a value of one of -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j. Both A1 and A2 are real numbers not equal to 0, and A1 < A2, and j represents the imaginary unit.

[0074] In some possible implementation manners, after the receiving end receives the second data frame, it performs signal processing on the second data frame.

[0075] In some possible implementation manners, the sum of the D pilot symbols is 0. That is to say, the sum of the real parts of the complex numbers corresponding to the D pilot symbols is 0, and the sum of the imaginary parts is also 0, so as to satisfy DC balance, which is beneficial to improving the quality of the signal recovered by the receiving end.

[0076] In some possible implementation manners, the D pilot symbols satisfy DC balance, which is beneficial to improving the quality of the signal recovered by the receiving end.

[0077] In some possible implementation manners, the total number of pilot symbols taking values of -A1 - A1j, -A1 + A1j, A1 - A1j, or A1 + A1j among the D pilot symbols is D1, and the total number of pilot symbols taking values of -A2 - A2j, -A2 + A2j, A2 - A2j, or A2 + A2j among the D pilot symbols is D2. D = D1 + D2, and both D1 and D2 are integers greater than 0. That is to say, in this implementation manner, each of the D pilot symbols takes a value of one of the 8 complex numbers -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j, -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j, which can better adapt to the scenario of DP - 16QAM.

[0078] In some possible implementations, the sum of the D1 pilot symbols is 0, the sum of the D2 pilot symbols is 0, and both D1 and D2 are even numbers. That is, the D1 pilot symbols corresponding to the inner circle of the constellation diagram satisfy DC balance, and the D2 pilot symbols corresponding to the outer circle of the constellation diagram also satisfy DC balance, so that all D pilot symbols satisfy DC balance, which is beneficial to improving the quality of signal recovery at the receiving end.

[0079] In some possible implementations, among the D1 pilot symbols, the number of pilot symbols with values ​​of -A1-A1j is d1, the number of pilot symbols with values ​​of -A1+A1j is d2, the number of pilot symbols with values ​​of A1-A1j is d3, and the number of pilot symbols with values ​​of A1+A1j is d4, where d1 = d4, d2 = d3, and D1 = d1 + d2 + d3 + d4. Among the D2 pilot symbols, the number of pilot symbols with values ​​of -A2-A2j is d5, the number of pilot symbols with values ​​of -A2+A2j is d6, the number of pilot symbols with values ​​of A2-A2j is d7, and the number of pilot symbols with values ​​of A2+A2j is d8, where d5 = d8, d6 = d7, and D2 = d5 + d6 + d7 + d8. This ensures that the sum of the D1 pilot symbols is 0 and the sum of the D2 pilot symbols is 0, so that all D pilot symbols satisfy DC balance, which is beneficial to improving the quality of the signal recovered by the receiver.

[0080] In some possible implementations, D1 ≥ D2. As an example, Probabilistic Constellation Shaping (PCS) is used to change the probability of constellation points appearing while keeping their positions constant, making them non-uniformly distributed, thereby improving system transmission performance. That is, the probability of a symbol being a constellation point symbol is different before framing. In this case, considering D1 > D2, the number of inner-circle constellation points in the constellation diagram among the D pilot symbols is greater than the number of outer-circle constellation points among the D pilot symbols, making the transmission performance cost caused by the D pilot symbols relatively low. As another example, conventional Quadrature Amplitude Modulation (QAM) modulation is used, where the probability of a symbol being a constellation point symbol is the same before framing. In this case, consider D1 = D2 = D / 2.

[0081] In some possible implementations, the number of pilot symbols with values ​​of -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j in the D1 pilot symbols differs from each other by less than or equal to 2, and the number of pilot symbols with values ​​of -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j in the D2 pilot symbols also differs from each other by less than or equal to 2. This effectively ensures that the number of pilot symbols with each value is nearly balanced, and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiving end.

[0082] In some possible implementations, D = 96, D1 = D / 2 = 48. Among the D1 pilot symbols, the number of pilot symbols with values ​​of -A1-A1j is d1, the number of pilot symbols with values ​​of -A1+A1j is d2, the number of pilot symbols with values ​​of A1-A1j is d3, and the number of pilot symbols with values ​​of A1+A1j is d4, where d1 = d4, d2 = d3, and D1 = d1 + d2 + d3 + d4. Alternatively, d1 = 11, d2 = 13, d3 = 13, d4 = 11; or d1 = 13, d2 = 11, d3 = 11, d4 = 13; or d1 = 12, d2 = 12, d3 = 12, d4 = 12. This effectively ensures that the number of pilot symbols for each value approaches balance and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0083] In some possible implementations, D = 96, D2 = D / 2 = 48. Among the D2 pilot symbols, the number of pilot symbols with values ​​of -A2-A2j is d5, the number of pilot symbols with values ​​of -A2+A2j is d6, the number of pilot symbols with values ​​of A2-A2j is d7, and the number of pilot symbols with values ​​of A2+A2j is d8, d5 = d8, d6 = d7, and D2 = d5 + d6 + d7 + d8. Alternatively, d5 = 11, d6 = 13, d7 = 13, d8 = 11; or d5 = 13, d6 = 11, d7 = 11, d8 = 13; or d5 = 12, d6 = 12, d7 = 12, d8 = 12. This effectively ensures that the number of pilot symbols for each value approaches balance and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiving end.

[0084] In some possible implementations, the first data frame includes a total of 2×D pilot symbols in both polarization directions. Among these 2×D pilot symbols, the number of values ​​-A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j is D / 4. This effectively ensures a balanced number of pilot symbols, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0085] In some possible implementations, the D pilot symbols included in the first data frame in the first polarization direction are different from the D pilot symbols included in the first data frame in the second polarization direction, so that the receiving end can distinguish the two polarization directions of the first data frame.

[0086] In some possible implementations, the first data frame uses a symbol mapping scheme of dual-polarization 16-ary Quadrature Amplitude Modulation (DP-16QAM), where A1 / A2 = 1 / 3. Alternatively, the first data frame uses a symbol mapping scheme of dual-polarization 64-ary Quadrature Amplitude Modulation (DP-64QAM), where A1 / A2 = 1 / 3, or A1 / A2 = 1 / 5, or A1 / A2 = 1 / 7, or A1 / A2 = 3 / 5, or A1 / A2 = 3 / 7, or A1 / A2 = 5 / 7.

[0087] In some possible implementations, the D pilot symbols are generated from a target polynomial and a seed in one polarization direction, which simplifies hardware implementation.

[0088] In some possible implementations, the order of the target polynomial is less than or equal to 11, and the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8. When selecting a polynomial, the order and the number of non-zero terms should be minimized to reduce the complexity and power consumption of the pilot symbol generation structure. Given a target polynomial, there may not be a seed that results in good autocorrelation and cross-correlation between the target polynomial and the pilot symbol sequence determined by the seed. Therefore, the selection of the target polynomial is not merely about minimizing the order and the number of non-zero terms; it also requires considering whether a corresponding seed can be selected that results in good autocorrelation and cross-correlation characteristics of the generated pilot symbol sequence, including its real and imaginary parts, to improve the quality of the recovered signal at the receiving end.

[0089] In some possible implementations, the target polynomial is one of the following: x10 + a9 × x 9 + a8 × x 8 + a7 × x 7 + a6 × x 6 + a5 × x 5 + a4 × x 4 + a3 × x 3 + a2 × x 2 + a1 × x + 1; x 9 + a8 × x 8 + a7 × x 7 + a6 × x 6 + a5 × x 5 + a4 × x 4 + a3 × x 3 + a2 × x 2 + a1 × x + 1; x 8 + a7 × x 7 + a6 × x 6 + a5 × x 5 + a4 × x 4 + a3 × x 3 + a2 × x 2 + a1 × x + 1; x 11 + a 10 × x 10 + a9 × x 9 + a8 × x 8 + a7 × x 7 + a6 × x 6 + a5 × x 5 + a4 × x 4 + a3 × x 3 + a2 × x 2 + a1 × x + 1。

[0090] In some possible embodiments, in one polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed, and every consecutive 3 bits in the first bit sequence correspond to a pilot symbol. This embodiment is applicable to the scenario where dual-polarization symbol mapping is performed first and then framing. It should be understood that there are a total of 8 combinations of the values of 3 bits, which can just correspond to the 8 values of the pilot symbols respectively, improving the feasibility of the present solution.

[0091] In some possible embodiments, every consecutive 3 bits in the first bit sequence are respectively b 3t , b 3t+1 , b 3t+2 , 0 ≤ t < D, and every consecutive 3 bits in the first bit sequence and the corresponding pilot symbol satisfy the relationship shown in one of the following tables.

[0092] Table 1-1a

[0093] Table 1-2a

[0094] Table 1-3a

[0095] Table 1-4a

[0096] Table 1-5a

[0097] Table 1-6a

[0098] Table 1-7a

[0099] Table 1-8a

[0100] Table 1-9a

[0101] Table 1-10a

[0102] Table 1-11a

[0103] Table 1-12a

[0104] In some possible embodiments, in one polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed. Each consecutive 3 bits in the first bit sequence correspond to 4 bits, and the 4 bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping is performed.

[0105] In some possible embodiments, each consecutive 3 bits in the first bit sequence are respectively b 3t , b 3t+1 , b 3t+2 , 0≤t<D, and the relationship between each consecutive 3 bits and the corresponding 4 bits in the first bit sequence satisfies one of the relationships shown in the following tables.

[0106] Table 1-1b

[0107] Table 1-2b

[0108] Table 1-3b

[0109] Table 1-4b

[0110] Table 1-5b

[0111] Table 1-6b

[0112] Table 1-7b

[0113] Table 1-8b

[0114] Table 1-9b

[0115] Table 1-10b

[0116] Table 1-11b

[0117] Table 1-12b

[0118] In some possible implementations, the D pilot symbols in the first polarization direction are generated by the target polynomial, the first seed, and the second seed, and the D pilot symbols in the second polarization direction are generated by the target polynomial, the third seed, and the fourth seed. The target polynomial and the first seed are used to obtain the quadrant of each pilot symbol in the first polarization direction, and the target polynomial and the second seed are used to obtain the amplitude of each pilot symbol in the first polarization direction. The target polynomial and the third seed are used to obtain the quadrant of each pilot symbol in the second polarization direction, and the target polynomial and the fourth seed are used to obtain the amplitude of each pilot symbol in the second polarization direction.

[0119] In some possible implementations, in the first polarization direction, a second bit sequence comprising 2×D bits is generated by the target polynomial and the first seed, and a third bit sequence comprising D bits is generated by the target polynomial and the second seed. Each pair of consecutive bits in the second bit sequence and one bit from the third bit sequence (a total of 3 bits) corresponds to one pilot symbol. In the second polarization direction, a fourth bit sequence comprising 2×D bits is generated by the target polynomial and the third seed, and a fifth bit sequence comprising D bits is generated by the target polynomial and the fourth seed. Each pair of consecutive bits in the fourth bit sequence and one bit from the fifth bit sequence (a total of 3 bits) corresponds to one pilot symbol. This implementation is suitable for scenarios where dual polarization symbol mapping is performed before framing.

[0120] In some possible embodiments, each consecutive 2 bits in the second bit sequence or the fourth bit sequence are respectively b 2t and b 2t+1 , and 1 bit in the third bit sequence or the fifth bit sequence is s t , where 0 ≤ t < D. Each consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding pilot symbol, and each consecutive 2 bits in the fourth bit sequence and 1 bit in the fifth bit sequence satisfy the relationship shown in one of the following tables with the corresponding pilot symbol.

[0121] Table 2-1a

[0122] Table 2-2a

[0123] In some possible embodiments, in the first polarization direction, the second bit sequence including 2×D bits is generated by the target polynomial and the first seed, and the third bit sequence including D bits is generated by the target polynomial and the second seed. Each consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to 4 first bits, and the 4 first bits are symbol-mapped to obtain a pilot symbol. In the second polarization direction, the fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed, and the fifth bit sequence including D bits is generated by the target polynomial and the fourth seed. Each consecutive 2 bits in the fourth bit sequence and 1 bit in the fifth bit sequence, a total of 3 bits, correspond to 4 second bits, and the 4 second bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping.

[0124] In some possible embodiments, each consecutive 2 bits in the second bit sequence or the fourth bit sequence are respectively b 2t and b 2t+1 , and 1 bit in the third bit sequence or the fifth bit sequence is s t , where 0 ≤ t < D. Each consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding 4 bits, and each consecutive 2 bits in the fourth bit sequence and 1 bit in the fifth bit sequence satisfy the relationship shown in one of the following tables with the corresponding 4 bits.

[0125] Table 2-1b

[0126] Table 2-2b

[0127] In some possible embodiments, D pilot symbols in the first polarization direction are generated by the target polynomial, the first seed, and the second seed, and D pilot symbols in the second polarization direction are generated by the target polynomial, the second seed, and the third seed. Among them, the target polynomial and the first seed are used to obtain the quadrant of each pilot symbol in the first polarization direction, the target polynomial and the third seed are used to obtain the quadrant of each pilot symbol in the second polarization direction, and the target polynomial and the second seed are used to obtain the amplitude of each pilot symbol in the first polarization direction and the amplitude of each pilot symbol in the second polarization direction.

[0128] In some possible embodiments, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed. In the first polarization direction, every 2 consecutive bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to a pilot symbol. In the second polarization direction, every 2 consecutive bits in the fourth bit sequence and the other 1 bit in the third bit sequence, a total of 3 bits, correspond to a pilot symbol. This embodiment is applicable to the scenario where double-polarization symbol mapping is performed first and then framing.

[0129] In some possible embodiments, every 2 consecutive bits in the second bit sequence are respectively and Every 2 consecutive bits in the fourth bit sequence are respectively and One bit in the third bit sequence is s 2t , and the other bit in the third bit sequence is s 2t+1 , 0≤t<D. Every 2 consecutive bits in the second bit sequence and one bit in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding pilot symbol, and every 2 consecutive bits in the fourth bit sequence and the other bit in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding pilot symbol.

[0130] Table 3-1a

[0131] Table 3-2a

[0132] In some possible embodiments, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed. In the first polarization direction, every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to 4 first bits, and the 4 first bits are symbol-mapped to obtain a pilot symbol. In the second polarization direction, every consecutive 2 bits in the fourth bit sequence and the other 1 bit in the third bit sequence, a total of 3 bits, correspond to 4 second bits, and the 4 second bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping is performed.

[0133] In some possible embodiments, every consecutive 2 bits in the second bit sequence are respectively and Every consecutive 2 bits in the fourth bit sequence are respectively and One bit in the third bit sequence is s 2t , and the other bit in the third bit sequence is s 2t+1 , 0≤t<D. Every consecutive 2 bits in the second bit sequence and one bit in the third bit sequence and the corresponding 4 bits satisfy the relationship shown in one of the following tables, and every consecutive 2 bits in the fourth bit sequence and the other bit in the third bit sequence and the corresponding 4 bits satisfy the relationship shown in one of the following tables.

[0134] Table 3-1b

[0135] Table 3-2b

[0136] In some possible embodiments, D = 96, and the 96 pilot symbols in the first polarization direction and the 96 pilot symbols in the second polarization direction of the first data frame satisfy the relationship shown in the following table, where the value of pi is 1 or 3, the value of qi is 1 or 3, and 1≤i≤96.

[0137] Table 4

[0138] In some possible embodiments, N = 6144 and M = 64.

[0139] In some possible embodiments, each of the pilot symbols is located at the starting position of the consecutive M symbols where it is located.

[0140] In a third aspect, an embodiment of the present application provides a data transmission device, including a processing unit and a sending unit. The processing unit is configured to: obtain a data frame. In one polarization direction, the data frame includes N symbols, and each consecutive M symbols in the N symbols include 1 pilot symbol and M - 1 payload symbols, N = M × D, where D is an even number, M is an integer greater than 1, at least one of the D pilot symbols takes a value of one of -A1 - A1j, -A1 + A1j, A1 - A1j, and A1 + A1j, and at least one of the D pilot symbols takes a value of one of -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j, where A1 and A2 are both real numbers not equal to 0, A1 < A2, and j represents the imaginary unit. The sending unit is configured to: send the data frame.

[0141] In some possible embodiments, the sum of the D pilot symbols is 0. That is, the sum of the real parts of the complex numbers corresponding to the D pilot symbols is 0, and the sum of the imaginary parts is also 0, so as to satisfy DC balance, which is beneficial to improving the quality of the signal recovered by the receiving end.

[0142] In some possible embodiments, the D pilot symbols satisfy DC balance, which is beneficial to improving the quality of the signal recovered by the receiving end.

[0143] In some possible embodiments, the total number of pilot symbols taking values of -A1 - A1j, -A1 + A1j, A1 - A1j, or A1 + A1j among the D pilot symbols is D1, and the total number of pilot symbols taking values of -A2 - A2j, -A2 + A2j, A2 - A2j, or A2 + A2j among the D pilot symbols is D2, D = D1 + D2, and D1 and D2 are both integers greater than 0. That is, in this embodiment, each of the D pilot symbols takes a value of one of the 8 complex numbers -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j, -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j, which can better adapt to the DP - 16QAM scenario.

[0144] In some possible embodiments, the sum of the D1 pilot symbols is 0, and the sum of the D2 pilot symbols is 0, and D1 and D2 are both even numbers. That is, the D1 pilot symbols corresponding to the inner circle of the constellation diagram satisfy DC balance, and the D2 pilot symbols corresponding to the outer circle of the constellation diagram also satisfy DC balance, so that all D pilot symbols satisfy DC balance, which is beneficial to improving the quality of the signal recovered by the receiving end.

[0145] In some possible implementations, among the D1 pilot symbols, the number of pilot symbols with values ​​of -A1-A1j is d1, the number of pilot symbols with values ​​of -A1+A1j is d2, the number of pilot symbols with values ​​of A1-A1j is d3, and the number of pilot symbols with values ​​of A1+A1j is d4, where d1 = d4, d2 = d3, and D1 = d1 + d2 + d3 + d4. Among the D2 pilot symbols, the number of pilot symbols with values ​​of -A2-A2j is d5, the number of pilot symbols with values ​​of -A2+A2j is d6, the number of pilot symbols with values ​​of A2-A2j is d7, and the number of pilot symbols with values ​​of A2+A2j is d8, where d5 = d8, d6 = d7, and D2 = d5 + d6 + d7 + d8. This ensures that the sum of the D1 pilot symbols is 0 and the sum of the D2 pilot symbols is 0, so that all D pilot symbols satisfy DC balance, which is beneficial to improving the quality of the signal recovered by the receiver.

[0146] In some possible implementations, D1 ≥ D2. As an example, Probabilistic Constellation Shaping (PCS) is used to change the probability of constellation points appearing while keeping their positions constant, making them non-uniformly distributed, thereby improving system transmission performance. That is, the probability of a symbol being a constellation point symbol is different before framing. In this case, considering D1 > D2, the number of inner-circle constellation points in the constellation diagram among the D pilot symbols is greater than the number of outer-circle constellation points among the D pilot symbols, making the transmission performance cost caused by the D pilot symbols relatively low. As another example, conventional Quadrature Amplitude Modulation (QAM) modulation is used, where the probability of a symbol being a constellation point symbol is the same before framing. In this case, consider D1 = D2 = D / 2.

[0147] In some possible implementations, the number of pilot symbols with values ​​of -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j in the D1 pilot symbols differs from each other by less than or equal to 2, and the number of pilot symbols with values ​​of -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j in the D2 pilot symbols also differs from each other by less than or equal to 2. This effectively ensures that the number of pilot symbols with each value is nearly balanced, and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiving end.

[0148] In some possible implementations, D = 96, D1 = D / 2 = 48. Among the D1 pilot symbols, the number of pilot symbols with values ​​of -A1-A1j is d1, the number of pilot symbols with values ​​of -A1+A1j is d2, the number of pilot symbols with values ​​of A1-A1j is d3, and the number of pilot symbols with values ​​of A1+A1j is d4, where d1 = d4, d2 = d3, and D1 = d1 + d2 + d3 + d4. Alternatively, d1 = 11, d2 = 13, d3 = 13, d4 = 11; or d1 = 13, d2 = 11, d3 = 11, d4 = 13; or d1 = 12, d2 = 12, d3 = 12, d4 = 12. This effectively ensures that the number of pilot symbols for each value approaches balance and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0149] In some possible implementations, D = 96, D2 = D / 2 = 48. Among the D2 pilot symbols, the number of pilot symbols with values ​​of -A2-A2j is d5, the number of pilot symbols with values ​​of -A2+A2j is d6, the number of pilot symbols with values ​​of A2-A2j is d7, and the number of pilot symbols with values ​​of A2+A2j is d8, d5 = d8, d6 = d7, and D2 = d5 + d6 + d7 + d8. Alternatively, d5 = 11, d6 = 13, d7 = 13, d8 = 11; or d5 = 13, d6 = 11, d7 = 11, d8 = 13; or d5 = 12, d6 = 12, d7 = 12, d8 = 12. This effectively ensures that the number of pilot symbols for each value approaches balance and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiving end.

[0150] In some possible implementations, the data frame includes a total of 2×D pilot symbols in both polarization directions. Among these 2×D pilot symbols, the number of values ​​for -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j is D / 4. This effectively ensures a balanced number of pilot symbols, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0151] In some possible implementations, the D pilot symbols included in the data frame in the first polarization direction are different from the D pilot symbols included in the data frame in the second polarization direction, which facilitates the receiving end to distinguish the two polarization directions of the data frame.

[0152] In some possible implementations, the data frame employs a symbol mapping scheme of Dual-polarization 16-ary Quadrature Amplitude Modulation (DP-16QAM), where A1 / A2 = 1 / 3. Alternatively, the data frame employs a symbol mapping scheme of Dual-polarization 64-ary Quadrature Amplitude Modulation (DP-64QAM), where A1 / A2 = 1 / 3, or A1 / A2 = 1 / 5, or A1 / A2 = 1 / 7, or A1 / A2 = 3 / 5, or A1 / A2 = 3 / 7, or A1 / A2 = 5 / 7.

[0153] In some possible implementations, the D pilot symbols are generated from a target polynomial and a seed in one polarization direction, which simplifies hardware implementation.

[0154] In some possible implementations, the order of the target polynomial is less than or equal to 11, and the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8. When selecting a polynomial, the order and the number of non-zero terms should be minimized to reduce the complexity and power consumption of the pilot symbol generation structure. Given a target polynomial, there may not be a seed that results in good autocorrelation and cross-correlation between the target polynomial and the pilot symbol sequence determined by the seed. Therefore, the selection of the target polynomial is not merely about minimizing the order and the number of non-zero terms; it also requires considering whether a corresponding seed can be selected that results in good autocorrelation and cross-correlation characteristics of the generated pilot symbol sequence, including its real and imaginary parts, to improve the quality of the recovered signal at the receiving end.

[0155] In some possible implementations, the target polynomial is one of the following: x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1; x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x2 +a1×x + 1; x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x + 1; x 11 +a 10 ×x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 + a1×x + 1。

[0156] In some possible embodiments, in one polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed, and every consecutive 3 bits in the first bit sequence correspond to a pilot symbol. This embodiment is applicable to the scenario where double-polarization symbol mapping is performed first and then framing. It should be understood that there are a total of 8 combinations of the values of 3 bits, which can just correspond to the 8 values of the pilot symbol respectively, improving the feasibility of this solution.

[0157] In some possible embodiments, every consecutive 3 bits in the first bit sequence are respectively b 3t 、b 3t+1 、b 3t+2 , 0 ≤ t < D, and every consecutive 3 bits in the first bit sequence and the corresponding pilot symbol satisfy the relationship shown in one of the following tables.

[0158] Table 1-1a

[0159] Table 1-2a

[0160] Table 1-3a

[0161] Table 1-4a

[0162] Table 1-5a

[0163] Table 1-6a

[0164] Table 1-7a

[0165] Table 1-8a

[0166] Table 1-9a

[0167] Table 1-10a

[0168] Table 1-11a

[0169] Table 1-12a

[0170] In some possible embodiments, in one polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed. Each consecutive 3 bits in the first bit sequence correspond to 4 bits, and the 4 bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping is performed.

[0171] In some possible embodiments, each consecutive 3 bits in the first bit sequence are respectively b 3t , b 3t+1 , b 3t+2 , 0≤t<D. Each consecutive 3 bits in the first bit sequence and the corresponding 4 bits satisfy one of the relationships shown in the following tables.

[0172] Table 1-1b

[0173] Table 1-2b

[0174] Table 1-3b

[0175] Table 1-4b

[0176] Table 1-5b

[0177] Table 1-6b

[0178] Table 1-7b

[0179] Table 1-8b

[0180] Table 1-9b<0001​​​Table 1-10b

[0182] Table 1-11b

[0183] Table 1-12b

[0184] In some possible embodiments, D pilot symbols in the first polarization direction are generated by the target polynomial, the first seed, and the second seed, and D pilot symbols in the second polarization direction are generated by the target polynomial, the third seed, and the fourth seed. Among them, the target polynomial and the first seed are used to obtain the quadrant of each pilot symbol in the first polarization direction, and the target polynomial and the second seed are used to obtain the amplitude of each pilot symbol in the first polarization direction. The target polynomial and the third seed are used to obtain the quadrant of each pilot symbol in the second polarization direction, and the target polynomial and the fourth seed are used to obtain the amplitude of each pilot symbol in the second polarization direction.

[0185] In some possible embodiments, in the first polarization direction, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, and a third bit sequence including D bits is generated by the target polynomial and the second seed. Every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to a pilot symbol. In the second polarization direction, a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed, and a fifth bit sequence including D bits is generated by the target polynomial and the fourth seed. Every consecutive 2 bits in the fourth bit sequence and 1 bit in the fifth bit sequence, a total of 3 bits, correspond to a pilot symbol. This embodiment is applicable to the scenario where dual-polarization symbol mapping is performed first and then framing.

[0186] In some possible embodiments, every consecutive 2 bits in the second bit sequence or the fourth bit sequence are respectively b 2t and b 2t+1 , and 1 bit in the third bit sequence or the fifth bit sequence is s t , 0≤t<D. Every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence and the corresponding pilot symbol satisfy the relationship shown in one of the following tables, and every consecutive 2 bits in the fourth bit sequence and 1 bit in the fifth bit sequence and the corresponding pilot symbol satisfy the relationship shown in one of the following tables.

[0187] Table 2-1a

[0188] Table 2-2a

[0189] In some possible embodiments, on the first polarization direction, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, and a third bit sequence including D bits is generated by the target polynomial and the second seed. Every two consecutive bits in the second bit sequence and one bit in the third bit sequence, a total of three bits, correspond to four first bits, and the four first bits are symbol-mapped to obtain a pilot symbol. On the second polarization direction, a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed, and a fifth bit sequence including D bits is generated by the target polynomial and the fourth seed. Every two consecutive bits in the fourth bit sequence and one bit in the fifth bit sequence, a total of three bits, correspond to four second bits, and the four second bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping is performed.

[0190] In some possible embodiments, every two consecutive bits in the second bit sequence or the fourth bit sequence are respectively b 2t and b 2t+1 , and one bit in the third bit sequence or the fifth bit sequence is s t , 0 ≤ t < D. Every two consecutive bits in the second bit sequence and one bit in the third bit sequence and the corresponding four bits satisfy the relationship shown in one of the following tables, and every two consecutive bits in the fourth bit sequence and one bit in the fifth bit sequence and the corresponding four bits satisfy the relationship shown in one of the following tables.

[0191] Table 2-1 b

[0192] Table 2-2 b

[0193] In some possible embodiments, D pilot symbols on the first polarization direction are generated by the target polynomial, the first seed, and the second seed, and D pilot symbols on the second polarization direction are generated by the target polynomial, the second seed, and the third seed. Among them, the target polynomial and the first seed are used to obtain the quadrant of each pilot symbol on the first polarization direction, the target polynomial and the third seed are used to obtain the quadrant of each pilot symbol on the second polarization direction, and the target polynomial and the second seed are used to obtain the amplitude of each pilot symbol on the first polarization direction and the amplitude of each pilot symbol on the second polarization direction.

[0194] In some possible embodiments, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed. In the first polarization direction, every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to a pilot symbol. In the second polarization direction, every consecutive 2 bits in the fourth bit sequence and the other 1 bit in the third bit sequence, a total of 3 bits, correspond to a pilot symbol. This embodiment is applicable to the scenario where dual-polarization symbol mapping is performed first and then framing is carried out.

[0195] In some possible embodiments, every consecutive 2 bits in the second bit sequence are respectively and Every consecutive 2 bits in the fourth bit sequence are respectively and One bit in the third bit sequence is s 2t , and the other bit in the third bit sequence is s 2t+1 , where 0 ≤ t < D. The relationship between every consecutive 2 bits in the second bit sequence and one bit in the third bit sequence and the corresponding pilot symbol satisfies one of the relationships shown in the following tables, and the relationship between every consecutive 2 bits in the fourth bit sequence and the other bit in the third bit sequence and the corresponding pilot symbol satisfies one of the relationships shown in the following tables.

[0196] Table 3-1a

[0197] Table 3-2a

[0198] In some possible embodiments, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed. In the first polarization direction, every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to 4 first bits, and the 4 first bits are symbol-mapped to obtain a pilot symbol. In the second polarization direction, every consecutive 2 bits in the fourth bit sequence and the other 1 bit in the third bit sequence, a total of 3 bits, correspond to 4 second bits, and the 4 second bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping is performed.

[0199] In some possible embodiments, every consecutive 2 bits in the second bit sequence are respectively and Every consecutive 2 bits in the fourth bit sequence are respectively and One bit in the third bit sequence is s 2t , and the other bit in the third bit sequence is s 2t+1 , where 0≤t<D. Every consecutive 2 bits in the second bit sequence and one bit in the third bit sequence and the corresponding 4 bits satisfy the relationship shown in one of the following tables, and every consecutive 2 bits in the fourth bit sequence and the other bit in the third bit sequence and the corresponding 4 bits satisfy the relationship shown in one of the following tables.

[0200] Table 3-1b

[0201] Table 3-2b

[0202] In some possible embodiments, D = 96, and the 96 pilot symbols in the first polarization direction and the 96 pilot symbols in the second polarization direction of the data frame satisfy the relationship shown in the following table, where the value of pi is 1 or 3, the value of qi is 1 or 3, and 1≤i≤96.

[0203] Table 4

[0204] In some possible embodiments, N = 6144 and M = 64.

[0205] In some possible embodiments, each of the pilot symbols is located at the starting position of a consecutive M symbols where it is located.

[0206] In a fourth aspect, an embodiment of the present application provides a data transmission device, including a receiving unit. The receiving unit is configured to: receive a second data frame transmitted through a channel from a first data frame. In one polarization direction, the first data frame includes N symbols, and each consecutive M symbols of the N symbols include 1 pilot symbol and M - 1 payload symbols. N = M × D, where D is an even number, M is an integer greater than 1, and at least one of the D pilot symbols takes a value of one of -A1 - A1j, -A1 + A1j, A1 - A1j, and A1 + A1j, and at least one of the D pilot symbols takes a value of one of -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j. A1 and A2 are both real numbers not equal to 0, and A1 < A2, and j represents the imaginary unit.

[0207] In some possible embodiments, the data transmission device further includes a processing unit, and the processing unit is configured to: perform signal processing on the second data frame.

[0208] In some possible embodiments, the sum of the D pilot symbols is 0. That is, the sum of the real parts of the complex numbers corresponding to the D pilot symbols is 0, and the sum of the imaginary parts is also 0, so as to satisfy DC balance, which is beneficial to improving the quality of the signal recovered at the receiving end.

[0209] In some possible embodiments, the D pilot symbols satisfy DC balance, which is beneficial to improving the quality of the signal recovered at the receiving end.

[0210] In some possible embodiments, the total number of pilot symbols taking values of -A1 - A1j, -A1 + A1j, A1 - A1j, or A1 + A1j among the D pilot symbols is D1, and the total number of pilot symbols taking values of -A2 - A2j, -A2 + A2j, A2 - A2j, or A2 + A2j among the D pilot symbols is D2, and D = D1 + D2, and D1 and D2 are both integers greater than 0. That is, in this embodiment, each of the D pilot symbols takes a value of one of the 8 complex numbers -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j, -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j, which can better adapt to the scenario of DP - 16QAM.

[0211] In some possible implementations, the sum of the D1 pilot symbols is 0, the sum of the D2 pilot symbols is 0, and both D1 and D2 are even numbers. That is, the D1 pilot symbols corresponding to the inner circle of the constellation diagram satisfy DC balance, and the D2 pilot symbols corresponding to the outer circle of the constellation diagram also satisfy DC balance, so that all D pilot symbols satisfy DC balance, which is beneficial to improving the quality of signal recovery at the receiving end.

[0212] In some possible implementations, among the D1 pilot symbols, the number of pilot symbols with values ​​of -A1-A1j is d1, the number of pilot symbols with values ​​of -A1+A1j is d2, the number of pilot symbols with values ​​of A1-A1j is d3, and the number of pilot symbols with values ​​of A1+A1j is d4, where d1 = d4, d2 = d3, and D1 = d1 + d2 + d3 + d4. Among the D2 pilot symbols, the number of pilot symbols with values ​​of -A2-A2j is d5, the number of pilot symbols with values ​​of -A2+A2j is d6, the number of pilot symbols with values ​​of A2-A2j is d7, and the number of pilot symbols with values ​​of A2+A2j is d8, where d5 = d8, d6 = d7, and D2 = d5 + d6 + d7 + d8. This ensures that the sum of the D1 pilot symbols is 0 and the sum of the D2 pilot symbols is 0, so that all D pilot symbols satisfy DC balance, which is beneficial to improving the quality of the signal recovered by the receiver.

[0213] In some possible implementations, D1 ≥ D2. As an example, Probabilistic Constellation Shaping (PCS) is used to change the probability of constellation points appearing while keeping their positions constant, making them non-uniformly distributed, thereby improving system transmission performance. That is, the probability of a symbol being a constellation point symbol is different before framing. In this case, considering D1 > D2, the number of inner-circle constellation points in the constellation diagram among the D pilot symbols is greater than the number of outer-circle constellation points among the D pilot symbols, making the transmission performance cost caused by the D pilot symbols relatively low. As another example, conventional Quadrature Amplitude Modulation (QAM) modulation is used, where the probability of a symbol being a constellation point symbol is the same before framing. In this case, consider D1 = D2 = D / 2.

[0214] In some possible implementations, the number of pilot symbols with values ​​of -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j in the D1 pilot symbols differs from each other by less than or equal to 2, and the number of pilot symbols with values ​​of -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j in the D2 pilot symbols also differs from each other by less than or equal to 2. This effectively ensures that the number of pilot symbols with each value is nearly balanced, and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiving end.

[0215] In some possible implementations, D = 96, D1 = D / 2 = 48. Among the D1 pilot symbols, the number of pilot symbols with values ​​of -A1-A1j is d1, the number of pilot symbols with values ​​of -A1+A1j is d2, the number of pilot symbols with values ​​of A1-A1j is d3, and the number of pilot symbols with values ​​of A1+A1j is d4, where d1 = d4, d2 = d3, and D1 = d1 + d2 + d3 + d4. Alternatively, d1 = 11, d2 = 13, d3 = 13, d4 = 11; or d1 = 13, d2 = 11, d3 = 11, d4 = 13; or d1 = 12, d2 = 12, d3 = 12, d4 = 12. This effectively ensures that the number of pilot symbols for each value approaches balance and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0216] In some possible implementations, D = 96, D2 = D / 2 = 48. Among the D2 pilot symbols, the number of pilot symbols with values ​​of -A2-A2j is d5, the number of pilot symbols with values ​​of -A2+A2j is d6, the number of pilot symbols with values ​​of A2-A2j is d7, and the number of pilot symbols with values ​​of A2+A2j is d8, d5 = d8, d6 = d7, and D2 = d5 + d6 + d7 + d8. Alternatively, d5 = 11, d6 = 13, d7 = 13, d8 = 11; or d5 = 13, d6 = 11, d7 = 11, d8 = 13; or d5 = 12, d6 = 12, d7 = 12, d8 = 12. This effectively ensures that the number of pilot symbols for each value approaches balance and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiving end.

[0217] In some possible implementations, the first data frame includes a total of 2×D pilot symbols in both polarization directions. Among these 2×D pilot symbols, the number of values ​​-A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j is D / 4. This effectively ensures a balanced number of pilot symbols, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0218] In some possible implementations, the D pilot symbols included in the first data frame in the first polarization direction are different from the D pilot symbols included in the first data frame in the second polarization direction, so that the receiving end can distinguish the two polarization directions of the first data frame.

[0219] In some possible implementations, the first data frame uses a symbol mapping scheme of dual-polarization 16-ary Quadrature Amplitude Modulation (DP-16QAM), where A1 / A2 = 1 / 3. Alternatively, the first data frame uses a symbol mapping scheme of dual-polarization 64-ary Quadrature Amplitude Modulation (DP-64QAM), where A1 / A2 = 1 / 3, or A1 / A2 = 1 / 5, or A1 / A2 = 1 / 7, or A1 / A2 = 3 / 5, or A1 / A2 = 3 / 7, or A1 / A2 = 5 / 7.

[0220] In some possible implementations, the D pilot symbols are generated from a target polynomial and a seed in one polarization direction, which simplifies hardware implementation.

[0221] In some possible implementations, the order of the target polynomial is less than or equal to 11, and the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8. When selecting a polynomial, the order and the number of non-zero terms should be minimized to reduce the complexity and power consumption of the pilot symbol generation structure. Given a target polynomial, there may not be a seed that results in good autocorrelation and cross-correlation between the target polynomial and the pilot symbol sequence determined by the seed. Therefore, the selection of the target polynomial is not merely about minimizing the order and the number of non-zero terms; it also requires considering whether a corresponding seed can be selected that results in good autocorrelation and cross-correlation characteristics of the generated pilot symbol sequence, including its real and imaginary parts, to improve the quality of the recovered signal at the receiving end.

[0222] In some possible implementations, the target polynomial is one of the following: x10 + a9 × x 9 + a8 × x 8 + a7 × x 7 + a6 × x 6 + a5 × x 5 + a4 × x 4 + a3 × x 3 + a2 × x 2 + a1 × x + 1; x 9 + a8 × x 8 + a7 × x 7 + a6 × x 6 + a5 × x 5 + a4 × x 4 + a3 × x 3 + a2 × x 2 + a1 × x + 1; x 8 + a7 × x 7 + a6 × x 6 + a5 × x 5 + a4 × x 4 + a3 × x 3 + a2 × x 2 + a1 × x + 1; x 11 + a 10 × x 10 + a9 × x 9 + a8 × x 8 + a7 × x 7 + a6 × x 6 + a5 × x 5 + a4 × x 4 + a3 × x 3 + a2 × x 2 + a1 × x + 1。

[0223] In some possible embodiments, in a polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed, and every consecutive 3 bits in the first bit sequence correspond to a pilot symbol. This embodiment is applicable to the scenario where dual-polarization symbol mapping is performed first and then framing. It should be understood that there are a total of 8 combinations of the values of 3 bits, which can just correspond to the 8 values of the pilot symbol respectively, improving the feasibility of the present solution.

[0224] In some possible embodiments, every consecutive 3 bits in the first bit sequence are respectively b 3t 、b 3t+1 、b 3t+2 , 0 ≤ t < D, and every consecutive 3 bits in the first bit sequence and the corresponding pilot symbol satisfy the relationship shown in one of the following tables.

[0225] Table 1-1a

[0226] Table 1-2a

[0227] Table 1-3a

[0228] Table 1-4a

[0229] Table 1-5a

[0230] Table 1-6a

[0231] Table 1-7a

[0232] Table 1-8a

[0233] Table 1-9a

[0234] Table 1-10a

[0235] Table 1-11a

[0236] Table 1-12a

[0237] In some possible embodiments, in a polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed. Each consecutive 3 bits in the first bit sequence correspond to 4 bits, and the 4 bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping is performed.

[0238] In some possible embodiments, each consecutive 3 bits in the first bit sequence are respectively b 3t , b 3t+1 , b 3t+2 , 0 ≤ t < D, and each consecutive 3 bits in the first bit sequence and the corresponding 4 bits satisfy the relationship shown in one of the following tables.

[0239] Table 1-1b

[0240] Table 1-2b

[0241] Table 1-3b

[0242] Table 1-4b

[0243] Table 1-5b

[0244] Table 1-6b

[0245] Table 1-7b

[0246] Table 1-8b

[0247] Table 1-9b

[0248] Table 1-10b

[0249] Table 1-11b

[0250] Table 1-12b

[0251] In some possible implementations, the D pilot symbols in the first polarization direction are generated by the target polynomial, the first seed, and the second seed, and the D pilot symbols in the second polarization direction are generated by the target polynomial, the third seed, and the fourth seed. The target polynomial and the first seed are used to obtain the quadrant of each pilot symbol in the first polarization direction, and the target polynomial and the second seed are used to obtain the amplitude of each pilot symbol in the first polarization direction. The target polynomial and the third seed are used to obtain the quadrant of each pilot symbol in the second polarization direction, and the target polynomial and the fourth seed are used to obtain the amplitude of each pilot symbol in the second polarization direction.

[0252] In some possible implementations, in the first polarization direction, a second bit sequence comprising 2×D bits is generated by the target polynomial and the first seed, and a third bit sequence comprising D bits is generated by the target polynomial and the second seed. Each pair of consecutive bits in the second bit sequence and one bit from the third bit sequence (a total of 3 bits) corresponds to one pilot symbol. In the second polarization direction, a fourth bit sequence comprising 2×D bits is generated by the target polynomial and the third seed, and a fifth bit sequence comprising D bits is generated by the target polynomial and the fourth seed. Each pair of consecutive bits in the fourth bit sequence and one bit from the fifth bit sequence (a total of 3 bits) corresponds to one pilot symbol. This implementation is suitable for scenarios where dual polarization symbol mapping is performed before framing.

[0253] In some possible embodiments, every two consecutive bits in the second bit sequence or the fourth bit sequence are respectively b 2t and b 2t+1 , and one bit in the third bit sequence or the fifth bit sequence is s t , where 0 ≤ t < D. Every two consecutive bits in the second bit sequence and one bit in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding pilot symbol, and every two consecutive bits in the fourth bit sequence and one bit in the fifth bit sequence satisfy the relationship shown in one of the following tables with the corresponding pilot symbol.

[0254] Table 2-1a

[0255] Table 2-2a

[0256] In some possible embodiments, in the first polarization direction, the second bit sequence including 2×D bits is generated by the target polynomial and the first seed, and the third bit sequence including D bits is generated by the target polynomial and the second seed. Every two consecutive bits in the second bit sequence and one bit in the third bit sequence, a total of three bits, correspond to four first bits, and the four first bits are symbol-mapped to obtain a pilot symbol. In the second polarization direction, the fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed, and the fifth bit sequence including D bits is generated by the target polynomial and the fourth seed. Every two consecutive bits in the fourth bit sequence and one bit in the fifth bit sequence, a total of three bits, correspond to four second bits, and the four second bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping is performed.

[0257] In some possible embodiments, every two consecutive bits in the second bit sequence or the fourth bit sequence are respectively b 2t and b 2t+1 , and one bit in the third bit sequence or the fifth bit sequence is s t , where 0 ≤ t < D. Every two consecutive bits in the second bit sequence and one bit in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding four bits, and every two consecutive bits in the fourth bit sequence and one bit in the fifth bit sequence satisfy the relationship shown in one of the following tables with the corresponding four bits.

[0258] Table 2-1b

[0259] Table 2-2b

[0260] In some possible embodiments, D pilot symbols in the first polarization direction are generated by the target polynomial, the first seed, and the second seed, and D pilot symbols in the second polarization direction are generated by the target polynomial, the second seed, and the third seed. Among them, the target polynomial and the first seed are used to obtain the quadrant of each pilot symbol in the first polarization direction, the target polynomial and the third seed are used to obtain the quadrant of each pilot symbol in the second polarization direction, and the target polynomial and the second seed are used to obtain the amplitude of each pilot symbol in the first polarization direction and the amplitude of each pilot symbol in the second polarization direction.

[0261] In some possible embodiments, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed. In the first polarization direction, every 2 consecutive bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to a pilot symbol. In the second polarization direction, every 2 consecutive bits in the fourth bit sequence and the other 1 bit in the third bit sequence, a total of 3 bits, correspond to a pilot symbol. This embodiment is applicable to the scenario where dual-polarization symbol mapping is performed first and then framing.

[0262] In some possible embodiments, every 2 consecutive bits in the second bit sequence are respectively and Every 2 consecutive bits in the fourth bit sequence are respectively and One bit in the third bit sequence is s 2t , and the other bit in the third bit sequence is s 2t+1 , 0 ≤ t < D. Every 2 consecutive bits in the second bit sequence and one bit in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding pilot symbol, and every 2 consecutive bits in the fourth bit sequence and the other bit in the third bit sequence satisfy the relationship shown in one of the following tables with the corresponding pilot symbol.

[0263] Table 3-1a

[0264] Table 3-2a

[0265] In some possible embodiments, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed. In the first polarization direction, every consecutive 2 bits in the second bit sequence and 1 bit in the third bit sequence, a total of 3 bits, correspond to 4 first bits, and the 4 first bits are symbol-mapped to obtain a pilot symbol. In the second polarization direction, every consecutive 2 bits in the fourth bit sequence and the other 1 bit in the third bit sequence, a total of 3 bits, correspond to 4 second bits, and the 4 second bits are symbol-mapped to obtain a pilot symbol. This embodiment is applicable to the scenario where framing is performed first and then dual-polarization symbol mapping is performed.

[0266] In some possible embodiments, every consecutive 2 bits in the second bit sequence are respectively and Every consecutive 2 bits in the fourth bit sequence are respectively and One bit in the third bit sequence is s 2t , and the other bit in the third bit sequence is s 2t+1 , where 0≤t<D. Every consecutive 2 bits in the second bit sequence and one bit in the third bit sequence and the corresponding 4 bits satisfy the relationship shown in one of the following tables, and every consecutive 2 bits in the fourth bit sequence and the other bit in the third bit sequence and the corresponding 4 bits satisfy the relationship shown in one of the following tables.

[0267] Table 3-1b

[0268] Table 3-2b

[0269] In some possible embodiments, D = 96, and the 96 pilot symbols in the first polarization direction and the 96 pilot symbols in the second polarization direction of the first data frame satisfy the relationship shown in the following table, where the value of pi is 1 or 3, the value of qi is 1 or 3, and 1≤i≤96.

[0270] Table 4

[0271] In some possible embodiments, N = 6144 and M = 64.

[0272] In some possible implementations, each pilot symbol is located at the beginning of a sequence of M consecutive symbols.

[0273] Fifthly, embodiments of this application provide a chip for performing the methods described in any of the first or second aspects.

[0274] In a sixth aspect, embodiments of this application provide an optical module, which includes a processor and an interface. The interface is used to transmit and receive signals, and the processor is used to execute the methods described in any embodiment of the first aspect. For example, the interface is used to transmit signals from the processor or to transmit received signals to the processor.

[0275] In a seventh aspect, embodiments of this application provide a transmitting device. The transmitting device includes a host-side device and an optical module as described in the sixth aspect, the optical module being used to convert electrical signals from the host-side device into optical signals and to transmit the optical signals.

[0276] Eighthly, embodiments of this application provide an optical module including a processor and an interface. The interface is used for transmitting and receiving signals, and the processor is used to execute the methods described in any embodiment of the second aspect. For example, the interface is used to transmit signals from the processor or to transmit received signals to the processor.

[0277] Ninthly, embodiments of this application provide a receiving device. The receiving device includes a host-side device and an optical module as described in the eighth aspect, the optical module being used to convert a received optical signal into an electrical signal and transmit the electrical signal to the host-side device.

[0278] In a tenth aspect, embodiments of this application provide a communication system including a transmitting device as described in the seventh aspect and a receiving device as described in the ninth aspect, wherein the transmitting device is used to transmit an optical signal to the receiving device.

[0279] In one aspect, this application provides a computer-readable storage medium storing instructions that, when executed by a computer, cause the method described in any embodiment of the first or second aspect to be implemented.

[0280] In a twelfth aspect, this application provides a computer program product including program instructions that, when executed, implement the method described in any of the embodiments of the first or second aspect above. Attached Figure Description

[0281] Figure 1 is a schematic diagram of a communication system applied in an embodiment of this application;

[0282] Figure 2(a) is a schematic diagram of one implementation of the starting DSP processor in an embodiment of this application;

[0283] Figure 2(b) is a schematic diagram of another implementation of the DSP processor in this application;

[0284] Figure 2(c) is a schematic diagram of another embodiment of the DSP processor in this application;

[0285] Figure 2(d) is a schematic diagram of another embodiment of the DSP processor in this application.

[0286] Figure 3 is a schematic diagram of a data transmission method in an embodiment of this application;

[0287] Figure 4 is a schematic diagram of the structure of a data frame in an embodiment of this application;

[0288] Figure 5 is a schematic diagram of a constellation diagram in an embodiment of this application;

[0289] Figure 6(a) is a schematic diagram of the first pilot symbol generation structure in the embodiments of this application;

[0290] Figure 6(b) is a schematic diagram of the second pilot symbol generation structure in the embodiments of this application;

[0291] Figure 6(c) is a schematic diagram of the third pilot symbol generation structure in the embodiments of this application;

[0292] Figure 6(d) is a schematic diagram of the fourth pilot symbol generation structure in the embodiments of this application;

[0293] Figure 7(a) is a schematic diagram of the fifth pilot symbol generation structure in the embodiments of this application;

[0294] Figure 7(b) is a schematic diagram of the sixth pilot symbol generation structure in the embodiments of this application;

[0295] Figure 8(a) is a schematic diagram of the seventh pilot symbol generation structure in the embodiments of this application;

[0296] Figure 8(b) is a schematic diagram of the eighth pilot symbol generation structure in the embodiments of this application;

[0297] Figure 9 is a schematic diagram of the structure of another data frame in an embodiment of this application;

[0298] Figure 10 is a schematic diagram of an embodiment of generating pilot symbols in this application;

[0299] Figure 11 is a schematic diagram reflecting the autocorrelation and cross-correlation characteristics in an embodiment of this application;

[0300] Figure 12 is a schematic diagram of another implementation method for generating pilot symbols in this application;

[0301] Figure 13 is a schematic diagram of another implementation method for generating pilot symbols in this application;

[0302] Figure 14 is a schematic diagram of a data transmission device in an embodiment of this application;

[0303] Figure 15 is a schematic diagram of another structure of the data transmission device in an embodiment of this application;

[0304] Figure 16 is a schematic diagram of a structure of an optical module in an embodiment of this application;

[0305] Figure 17 is a schematic diagram of a transmitting device in an embodiment of this application;

[0306] Figure 18 is a schematic diagram of a receiving device in an embodiment of this application. Detailed Implementation

[0307] This application provides a data transmission method, apparatus, and system that have a low cost in terms of actual transmission performance and are beneficial for improving the quality of signal recovery at the receiving end, and can be well applied to various coherent transmission scenarios.

[0308] It should be noted that the terms "first," "second," etc., in this application specification, claims, and the accompanying drawings are used to distinguish similar objects, not to limit a specific order or sequence. It should be understood that the above terms can be used interchangeably where appropriate so that the embodiments described in this application can be implemented in a sequence other than that described in this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover 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 steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0309] Figure 1 is a schematic diagram of a communication system applied in an embodiment of this application. As shown in Figure 1, at the transmitting end, the source provides a data stream to be transmitted. A forward error correction (FEC) encoder receives the data stream and performs FEC encoding on it; the codeword information obtained by FEC encoding (including parity bits and information bits) is sent to the transmitting end digital signal processing (DSP) processor for framing, and then transmitted through the channel to the receiving end. After receiving the distorted signal caused by noise or other impairments in the channel, the receiving end sends it to the receiving end DSP processor for dispersion compensation, synchronization, phase recovery, and other operations, and then decodes it through the FEC decoder to recover the original data and send it to the destination. The above-mentioned framing can also be called DSP framing.

[0310] Figure 2(a) is a schematic diagram of one implementation of the transmitting DSP processor in this application. As shown in Figure 2(a), in one possible implementation, the transmitting DSP processor performs dual-polarization symbol mapping on the received data sequence. Typically, the received data sequence is information and a check sequence obtained through FEC encoding. Dual-polarization symbol mapping includes symbol mapping and polarization distribution. The symbol mapping method is Quadrature Amplitude Modulation (QAM). Typically, QAM modulation (also called symbol mapping) involves symbol mapping multiple input bits to obtain multiple QAM symbols, and polarization distribution of the multiple QAM symbols to obtain multiple dual-polarization (DP) symbols, i.e., DP-QAM symbols, such as DP-16QAM, DP-32QAM, and DP-64QAM. For ease of explanation, the two polarization directions will be uniformly referred to as the X-polarization direction and the Y-polarization direction, respectively, wherein 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 rather two arbitrarily orthogonal polarization directions. Therefore, the transmitting DSP processor performs framing processing on a certain number of dual-polarization symbols as follows: specifically, it obtains a pre-framing dual-polarization symbol sequence containing multiple dual-polarization symbols, and inserts multiple pilot symbols in both the X-polarization and Y-polarization directions to obtain a post-framing dual-polarization symbol sequence. The sequence containing multiple pilot symbols is also called a pilot symbol sequence or pilot sequence.

[0311] In some specific applications, the framed dual-polarization symbol sequence is referred to as a frame, a data frame, or a DSP frame. For ease of explanation, this application embodiment will uniformly refer to the framed dual-polarization symbol sequence as a data frame.

[0312] It should be understood that a dual-polarization symbol can be represented by two symbols, one located in the X-polarization direction and the other in the Y-polarization direction. Each symbol can be represented by a complex number. For example, a symbol obtained using 16QAM modulation can be represented by any one of the following 16 complex numbers: ±1±1j, ±1±3j, ±3±1j, and ±3±3j, where ± indicates a positive or negative value, such as ±3 representing 3 or -3. Here, j represents the imaginary unit. In some scenarios, the imaginary unit may also be represented by other symbols such as i, which is not limited here. In the embodiments of this application, the imaginary unit is uniformly represented by j. In some specific applications, the real and imaginary parts may be normalized, but the essence remains unchanged.

[0313] It should be noted that a sequence containing L dual-polarization symbols can be represented by two complex sequences of length L, where one sequence represents the symbol in the X-polarization direction and the other represents the symbol in the Y-polarization direction. Each complex sequence of length L consists of a sequence of length L's real part (also called the I-path sequence) and a sequence of length L's imaginary part (also called the Q-path sequence), where L is an integer greater than 1. Therefore, there are four different types of sequences: X-polarization direction I-path (in-phase component) sequence, X-polarization direction Q-path (quadrature-phase component) sequence, Y-polarization direction I-path sequence, and Y-polarization direction Q-path sequence. The X-polarization direction I-path sequence is also called X... I The component, the Q-path sequence in the X polarization direction, is also called X. Q The component, the Y-polarization direction I-path sequence, is also called the Y component. I The component, the Q-path sequence in the Y-polarization direction, is also called the Y-axis. Q Quantity.

[0314] It should be noted that after dual-polarization symbol mapping and framing operations, a dual-polarization symbol data stream to be transmitted is obtained. This stream can be represented by two symbol data streams: the first is the symbol data stream in the X-polarization direction, and the second is the symbol data stream in the Y-polarization direction. Alternatively, a dual-polarization symbol data stream can also be represented by four data streams, where the first is the data stream corresponding to the I-path component in the X-polarization direction (referred to as X...). I The second data stream is the data stream of the Q-path component in the X-polarization direction corresponding to the dual-polarization symbol stream (abbreviated as X).Q The third data stream is the data stream of the I-path component in the Y-polarization direction corresponding to the dual-polarization symbol stream (abbreviated as Y). I The fourth data stream is the data stream of the Q-path component in the Y-polarization direction corresponding to the dual-polarization symbol stream (abbreviated as Y). Q (Data flow).

[0315] It should be understood that in the dual-polarization symbol mapping and framing operation shown in Figure 2(a), framing (also known as DSP framing) is performed after dual-polarization symbol mapping, that is, framing is performed on the symbol level. Below are schematic diagrams of several other possible implementations of the originating DSP processor, where framing is performed before dual-polarization symbol mapping, that is, framing is performed on the bit level.

[0316] Figure 2(b) is a schematic diagram of another implementation of the transmitting DSP processor in this application. As shown in Figure 2(b), framing is performed before dual-polarization symbol mapping. Specifically, a pre-framing bit sequence containing multiple bits is obtained, a target bit sequence is inserted, and dual-polarization symbol mapping is performed to obtain a post-framing dual-polarization symbol sequence. The target bit sequence is then processed by dual-polarization symbol mapping to obtain a pilot symbol sequence, and the target bit sequence is also referred to as the bits corresponding to the pilot sequence. It should be understood that the post-framing dual-polarization symbol sequence obtained by using the implementation shown in Figure 2(b) is the same as the post-framing dual-polarization symbol sequence obtained by using the implementation shown in Figure 2(a).

[0317] Figure 2(c) is a schematic diagram of another embodiment of the transmitting DSP processor in this application. As shown in Figure 2(c), framing is performed before dual-polarization symbol mapping. Specifically, two pre-framing bit sequences containing multiple bits are obtained respectively. A first target bit sequence and a second target bit sequence are inserted into the first and second pre-framing bit sequences respectively, and dual-polarization symbol mapping is performed to obtain a post-framing dual-polarization symbol sequence. The first target bit sequence is symbol mapped to obtain a pilot symbol sequence in the X-polarization direction, and the second target bit sequence is symbol mapped to obtain a pilot symbol sequence in the Y-polarization direction. The first target bit sequence is also called the bit corresponding to the pilot sequence in the X-polarization direction, and the second target bit sequence is also called the bit corresponding to the pilot sequence in the Y-polarization direction. It should be understood that the post-framing dual-polarization symbol sequence obtained by the pre-framing bit sequence using the embodiment shown in Figure 2(c) is the same as the post-framing dual-polarization symbol sequence obtained by the embodiment shown in Figure 2(a).

[0318] Figure 2(d) is a schematic diagram of another embodiment of the transmitting DSP processor in this application. As shown in Figure 2(d), framing is performed before dual-polarization symbol mapping. Specifically, four pre-framing bit sequences containing multiple bits are obtained respectively. A first target bit sequence, a second target bit sequence, a third target bit sequence, and a fourth target bit sequence are inserted into the first, second, third, and fourth pre-framing bit sequences respectively, and dual-polarization symbol mapping is performed to obtain the post-framing dual-polarization symbol sequence. The first target bit sequence is symbol mapped to obtain the I-path component of the pilot symbol sequence in the X-polarization direction, the second target bit sequence is symbol mapped to obtain the Q-path component of the pilot symbol sequence in the X-polarization direction, the third target bit sequence is symbol mapped to obtain the I-path component of the pilot symbol sequence in the Y-polarization direction, and the fourth target bit sequence is symbol mapped to obtain the Q-path component of the pilot symbol sequence in the Y-polarization direction. The first target bit sequence is also called the pilot sequence in the X-polarization direction. I The bits corresponding to the components, the second target bit sequence, also known as the pilot sequence in X Q The bits corresponding to the components, the third target bit sequence, also known as the pilot sequence, are in Y. I The bits corresponding to the components, the fourth target bit sequence, also known as the pilot sequence, are in Y. Q The bits corresponding to the components. It should be understood that the framed dual-polarization symbol sequence obtained by using the implementation shown in Figure 2(d) before framing is the same as the framed dual-polarization symbol sequence obtained by using the implementation shown in Figure 2(a).

[0319] It should be noted that this application does not limit the specific framing method adopted by the sending DSP processor. In addition to the framing methods described in Figures 2(a), 2(b), 2(c), and 2(d), other similar framing methods are also applicable to this scheme, and will not be described in detail here.

[0320] Figure 3 is a schematic diagram of a data transmission method according to an embodiment of this application. As shown in Figure 3, the data transmission method includes the following steps.

[0321] 101. The sending end obtains the data frame.

[0322] It should be noted that this application does not limit the specific implementation method of generating data frames. For example, the dual-polarization symbol mapping and framing method described in Figures 2(a), 2(b), 2(c), or 2(d) can be used. Of course, other similar dual-polarization symbol mapping and framing methods are also applicable to this scheme, and will not be described in detail here. It should be understood that a data frame includes symbols in two polarization directions. The structure of the data frame is similar in both polarization directions. 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 using one polarization direction as an example.

[0323] Figure 4 is a schematic diagram of a data frame structure in an embodiment of this application. As shown in Figure 4, a data frame (also called a DSP frame) in one polarization direction includes N symbols. Every M consecutive symbols in the N symbols include one pilot symbol and M-1 payload symbols located at a fixed position, where N = M × D, D is an even number, and M is an integer greater than 1. It should be understood that every M consecutive symbols in the N symbols can be regarded as a group, and the N symbols include a total of D groups of symbols. For example, N = 6144, M = 64, D = 96, symbols 1-64 are the first group of 64 consecutive symbols, symbols 65-128 are the second group of 64 consecutive symbols, ..., symbols 6081-6144 are the 96th group of 64 consecutive symbols. That is, in a data frame consisting of N = 6144 dual-polarization symbols, starting from the beginning, the first dual-polarization symbol in every M = 64 dual-polarization symbols is a pilot symbol, totaling D = 96 dual-polarization pilot symbols. It should be understood that the payload symbol, also known as the pre-framing symbol, includes FEC-encoded information and check bits, which are then symbolized through symbol mapping to obtain the symbol (called the information symbol and check symbol). At the receiving end, the pilot symbols can be used to assist in carrier phase recovery and to distinguish between the two polarization directions. In other possible scenarios, M can also be 32, 96, or 128, etc., and is not limited here.

[0324] It should be understood that this application does not limit the specific location of the pilot symbol in each group of M symbols. As an example, each pilot symbol is located at the starting position of the consecutive M symbols. For example, the first symbol in the data frame shown in Figure 4 is the first pilot symbol.

[0325] It should be noted that the data frame (DSP frame) composed of N symbols contains D pilot symbols. Each pilot symbol takes one of the 8 complex numbers: -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j, -A2 - A2j, -A2 + A2j, A2 - A2j, A2 + A2j, where A1 and A2 are real numbers not equal to 0, and A1 < A2, and j represents the imaginary unit. Moreover, the D pilot symbols satisfy direct current balance, that is, the sum of the D pilot symbols is 0. More specifically, the sum of the real parts of the complex numbers corresponding to the D pilot symbols is 0, and the sum of the imaginary parts is also 0, which can achieve direct current balance and is beneficial to improving the quality of the signal recovered at the receiving end. Here, A1j can also be written as A1×j, and A2j can also be written as A2×j. Here, the real part of a complex number is also called the I-channel component, and the imaginary part of a complex number is also called the Q-channel component.

[0326] In some specific applications, the complex numbers -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j, -A2 - A2j, -A2 + A2j, A2 - A2j, A2 + A2j are the constellation points corresponding to the symbol mapping adopted. It should be noted that -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j can be expressed as (-1 - 1j)×A1, (-1 + 1j)×A1, (1 - 1j)×A1, (1 + 1j)×A1, and -A2 - A2j, -A2 + A2j, A2 - A2j, A2 + A2j can be expressed as (-1 - 1j)×A2, (-1 + 1j)×A2, (1 - 1j)×A2, (1 + 1j)×A2. Considering A1 < A2, it should be understood that the 4 constellation points corresponding to -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j are the points in the inner circle of the constellation diagram, and the 4 constellation points corresponding to -A2 - A2j, -A2 + A2j, A2 - A2j, A2 + A2j are the points in the outer circle of the constellation diagram.

[0327] FIG. 5 is a schematic diagram of a constellation diagram in an embodiment of the present application. As shown in FIG. 5, the constellation diagram can be divided into four regions according to the horizontal axis and the vertical axis, and each region is called a quadrant. Among them, A1 + A1j and A2 + A2j are located in the first quadrant, -A1 + A1j and -A2 + A2j are located in the second quadrant, -A1 - A1j and -A2 - A2j are located in the third quadrant, and A1 - A1j and A2 - A2j are located in the fourth quadrant.

[0328] In some specific applications, taking 16QAM symbol mapping as an example, A2 = 3 × A1. The values of the 16 constellation points (also called symbols) on the adopted 16QAM constellation diagram are {±1 ± 1j, ±1 ± 3j, ±3 ± 1j, ±3 ± 3j}, with A1 = 1 and A2 = 3. As shown in the example of (a) in FIG. 5, hollow circles are used to represent the 4 outermost constellation points in the constellation diagram, namely the symbols -3 - 3j, -3 + 3j, 3 - 3j, 3 + 3j; circles filled with vertical lines are used to represent the 4 innermost constellation points in the constellation diagram, namely the symbols -1 - 1j, -1 + 1j, 1 - 1j, 1 + 1j.

[0329] It should be noted that, as shown in the example of (b) in FIG. 5, a 16QAM symbol mapping method is also given. A 16QAM symbol in the X polarization direction or the Y polarization direction is obtained by mapping 4 bits. For example, 0000 is mapped to -3 - 3j, 0101 is mapped to -1 - 1j, 0010 is mapped to -3 + 3j, 0111 is mapped to -1 + 1j, 1010 is mapped to 3 + 3j, 1111 is mapped to 1 + 1j, 1000 is mapped to 3 - 3j, 1101 is mapped to 1 - 1j.

[0330] In some other specific applications, taking 64QAM symbol mapping as an example. The values of the 64 symbols on the adopted 64QAM constellation diagram are {±1 ± 1j, ±1 ± 3j, ±1 ± 5j, ±1 ± 7j, ±3 ± 1j, ±5 ± 1j, ±7 ± 1j, ±3 ± 3j, ±3 ± 5j, ±3 ± 7j, ±5 ± 3j, ±7 ± 3j, ±5 ± 5j, ±5 ± 7j, ±7 ± 5j, ±7 ± 7j}, with A1 = 1 or 3 or 5, A2 = 3 or 5 or 7, and A1 < A2. That is, A1 / A2 = 1 / 3, or A1 / A2 = 1 / 5, or A1 / A2 = 1 / 7, or A1 / A2 = 3 / 5, or A1 / A2 = 3 / 7, or A1 / A2 = 5 / 7. Typically, A1 = 3 and A2 = 5 are selected to make the sensitivity of D pilot symbols better and the transmission performance cost relatively lower.

[0331] It should be understood that in some possible scenarios, in addition to the above 8 complex numbers of -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j, -A2 - A2j, -A2 + A2j, A2 - A2j, A2 + A2j, the pilot symbol may also have more other values, and the specific number of possible values of the pilot symbol is not limited here. Taking 64QAM symbol mapping as an example, the value of the pilot symbol can also be -A

[0332] It should be noted that it's also possible to compress the symbols on the constellation diagram. Correspondingly, the values ​​of A1 and A2 will also be compressed. For example, power normalization can be performed on the 16 symbols on a 16QAM constellation diagram. In this case, the values ​​of the 16 symbols on the 16QAM constellation diagram become... have and For example, power normalization of the 64 symbols on the 64QAM constellation diagram yields: or or or or And A1 <A2。

[0333] In this embodiment, the total number of pilot symbols with values ​​of -A1-A1j, -A1+A1j, A1-A1j, or A1+A1j among the D pilot symbols is D1, and the total number of pilot symbols with values ​​of -A2-A2j, -A2+A2j, A2-A2j, or A2+A2j among the D pilot symbols is D2, where integer D1>0, integer D2>0, and D1+D2=D. It should be understood that some values ​​of the D pilot symbols are in the inner circle of the constellation diagram, and some are in the outer circle, resulting in generally low noise and sensitivity for the D pilot symbols, but with relatively low peak-to-average power ratio and transmission performance costs. Typically, D1≥D2. It should also be understood that each pilot symbol in the D1 pilot symbols can take the values ​​-A1-A1j, -A1+A1j, A1-A1j, or A1+A1j. However, not all four values ​​of the pilot symbols may exist in the D1 pilot symbols; for example, only two of the values ​​may exist. Similarly, each pilot symbol in the D2 pilot symbols can take the values ​​-A2-A2j, -A2+A2j, A2-A2j, or A2+A2j. However, not all four values ​​of the pilot symbols may exist in the D2 pilot symbols; for example, only two of the values ​​may exist.

[0334] In some specific applications, Probabilistic Constellation Shaping (PCS) is employed to change the probability of constellation points appearing while keeping their positions constant, resulting in a non-uniform distribution and thus improving system transmission performance. In other words, the probability of a symbol being a constellation point symbol is different before framing. In this case, considering D1 > D2, the number of inner-circle constellation points in the constellation diagram among the D pilot symbols is greater than the number of outer-circle constellation points, making the transmission performance cost caused by the D pilot symbols relatively low.

[0335] In other specific applications, traditional QAM modulation is used, where the probability of a symbol being a constellation point symbol is the same before framing. In this case, consider D1 = D2 = D / 2.

[0336] The following is a specific implementation method for achieving DC balance among the D pilot symbols. The D1 pilot symbols with values ​​of -A1-A1j, -A1+A1j, A1-A1j, or A1+A1j among the D pilot symbols satisfy DC balance, meaning the sum of the D1 pilot symbols in the inner circle is 0. The number of pilot symbols with values ​​of -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j among the D1 pilot symbols are d1, d2, d3, and d4 respectively, where d1 = d4, d2 = d3, and d1 + d2 + d3 + d4 = D1. On the other hand, the D2 pilot symbols with values ​​of -A2-A2j, -A2+A2j, A2-A2j, or A2+A2j among the D pilot symbols also satisfy DC balance, meaning the sum of the D2 pilot symbols in the outer circle is 0. The number of pilot symbols with values ​​-A2-A2j, -A2+A2j, A2-A2j, and A2+A2j are d5, d6, d7, and d8, respectively, where d5 = d8, d6 = d7, and d5 + d6 + d7 + d8 = D2. This ensures that the D pilot symbols also achieve DC balance, which is beneficial for improving the quality of the recovered signal at the receiver. Here, D1 and D2 are both even numbers. In some specific applications, traditional QAM modulation is used, and considering D1 = D2 = D / 2, the value of D is an integer multiple of 4.

[0337] Furthermore, in one polarization direction, the number of the D pilot symbols -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j differs from each other by less than or equal to 2, and the number of the D pilot symbols -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j also differs from each other by less than or equal to 2. This effectively ensures that the number of pilot symbols for each value approaches balance, and also ensures that the sequence of pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiving end. For example, consider D = 96, D1 = D2 = D / 2 = 48. At this time, the number of the 96 pilot symbols -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j can be d1=11, d2=13, d3=13, and d4=11 respectively, or d1=13, d2=11, d3=11, and d4=13 respectively, or d1=12, d2=12, d3=12, and d4=12 respectively; the number of the 96 pilot symbols -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j can be d5=11, d6=13, d7=13, and d8=11 respectively, or d5=13, d6=11, d7=11, and d8=13 respectively, or d5=12, d6=12, d7=12, and d8=12 respectively.

[0338] It should also be noted that in some specific applications, the data frame includes a total of 2×D pilot symbols in the X-polarization and Y-polarization directions. Among these 2×D pilot symbols, the number of values ​​for -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j is always D / 4. This effectively ensures that the number of pilot symbols for each value is nearly balanced, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0339] In a data frame, the sequence of D pilot symbols in the X-polarization direction (also called the pilot sequence) is distinct from the sequence of D pilot symbols in the Y-polarization direction. Specifically, the pilot sequence in the X-polarization direction and the pilot sequence in the Y-polarization direction differ in at least one position. For example, if the sequence of 8 pilot symbols in the X-polarization direction is -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, A2+A2j, then the sequence of 8 pilot symbols in the Y-polarization direction cannot be exactly the same. It can be -A1+A1j, -A1-A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, A2+A2j, to avoid the receiver being unable to distinguish between the two polarization directions during actual transmission.

[0340] In some specific applications, for the sake of hardware simplicity, pilot symbols in data frames are generated using a target polynomial and a seed. Several possible methods for generating pilot symbols are described below from multiple perspectives.

[0341] Firstly, the D pilot symbols in the X-polarization direction are generated by the target polynomial and the seed in the X-polarization direction; the D pilot symbols in the Y-polarization direction are generated by the target polynomial and the seed in the Y-polarization direction. In this embodiment, the same target generating polynomial can be used for pilot symbols in two orthogonal polarization directions, but since the seeds used in the two polarization directions are different, the D pilot symbols obtained in the two polarization directions are not exactly the same.

[0342] Figure 6(a) is a schematic diagram of the first pilot symbol generation structure in the embodiment of this application. The target polynomial is a 10th-order polynomial, which can be expressed as: x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1. Where a9…a1 can take the values ​​0 or 1.

[0343] It should be noted that an algebraic expression composed of the addition (or subtraction) of several monomials is called a polynomial. Each monomial in a polynomial is called a term of the polynomial, and the degree of the highest term among these monomials is the degree of the polynomial. The number of terms in a polynomial refers to the number of the monomials with non-zero coefficients; for example, the number of terms in the 10th-order polynomial mentioned above is equal to the number of non-zero terms in a9…a1 plus 2.

[0344] In some specific applications, the number of non-zero terms in a9…a1 is no greater than 6, meaning the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8, resulting in lower hardware implementation complexity. As shown in Figure 6(a), each box can be considered a storage unit, and the number of storage units is the same as the number of bits in the preloaded seed. That is, each storage unit is used to input the corresponding bit in the seed. For example, if the seed length is 10 bits, it can be represented in binary as b9, b8, b7, b6, b5, b4, b3, b2, b1, b0, then 10 corresponding storage units are used. Of course, the seed can also be represented in hexadecimal or decimal. When it is used in operation with the target polynomial, it needs to be converted to binary form. For example, 0110111000 is represented as 0x1B8 in hexadecimal and 440 in decimal.

[0345] It should be noted that the polynomial x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1 can sometimes be written as x^10+a9×(x^9)+a8×(x^8)+a7×(x^7)+a6×(x^6)+a5×(x^5)+a4×(x^4)+a3×(x^3)+a2×(x^2)+a1×x+1.

[0346] Figure 6(b) is a schematic diagram of the second pilot symbol generation structure in an embodiment of this application. The target polynomial is a 9th-order polynomial, which can be expressed as: x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2+a1×x+1. Where a8…a1 can take values ​​of 0 or 1. In some specific applications, the number of non-zero terms in a8…a1 is no greater than 6, meaning the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8, resulting in lower hardware implementation complexity. As shown in Figure 6(b), the seed length is 9 bits, which can be represented in binary as b8, b7, b6, b5, b4, b3, b2, b1, b0. Of course, the seed can also be represented in hexadecimal or decimal, but it needs to be converted to binary form when operating with the target polynomial.

[0347] Figure 6(c) is a schematic diagram of the third pilot symbol generation structure in this embodiment. The target polynomial is an 8th-order polynomial, which can be expressed as: x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1. Where a7…a1 can take values ​​of 0 or 1. In some specific applications, the number of non-zero terms in a7…a1 is no greater than 6, meaning the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8, resulting in lower hardware implementation complexity. As shown in Figure 6(c), the seed length is 8 bits, which can be represented in binary as b7, b6, b5, b4, b3, b2, b1, b0. Of course, the seed can also be represented in hexadecimal or decimal, but it needs to be converted to binary form when operating with the target polynomial.

[0348] Figure 6(d) is a schematic diagram of the fourth pilot symbol generation structure in this embodiment. The target polynomial is an 11th-order polynomial, which can be expressed as: x 11 +a 10 ×x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1. Where a 10 …a1 can take the value 0 or 1. In some specific applications, a… 10 …The number of non-zero terms in a1 is no greater than 6, meaning the number of terms in the objective polynomial is greater than or equal to 2 and less than or equal to 8, resulting in low hardware implementation complexity. As shown in Figure 6(d), the seed length is 11 bits, which can be represented in binary as b 10, b9, b8, b7, b6, b5, b4, b3, b2, b1, b0. Of course, the seed can also be represented in hexadecimal or decimal, and needs to be converted to binary form when operating with the target polynomial.

[0349] In FIGS. 6(a), 6(b), 6(c), and 6(d), for the scenario of generating D pilot symbols in one polarization direction, a bit sequence b0, b1, b2, … b including 3×D bits is obtained according to the target polynomial and the seed. 3D-1 . The above bit sequence is also called a Pseudo Random Binary Sequence (PRBS). The bit sequence generated by an 8th-order polynomial is also called PRBS8, the bit sequence generated by a 9th-order polynomial is also called PRBS9, the bit sequence generated by a 10th-order polynomial is also called PRBS10, and the bit sequence generated by an 11th-order polynomial is also called PRBS11. Every 3 consecutive bits in the bit sequence b0, b1, b2, … b 3D-1 are denoted as b 3t , b 3t+1 , b 3t+2 (0 ≤ t < D). Every 3 consecutive bits in the bit sequence b0, b1, b2, … b 3D-1 are used to map to one of the D pilot symbols. In some specific applications, b 3t and b 3t+1 are used to obtain the quadrant corresponding to the pilot symbol, and b 3t+2 is used to obtain the amplitude corresponding to the pilot symbol; in some other specific applications, b 3t and b 3t+2 are used to obtain the quadrant corresponding to the pilot symbol, and b 3t+1 is used to obtain the amplitude corresponding to the pilot symbol; in some other specific applications, b 3t+1 and b 3t+2 are used to obtain the quadrant corresponding to the pilot symbol, and b 3t is used to obtain the amplitude corresponding to the pilot symbol.

[0350] In some specific applications, the framing operation is after the dual-polarization symbol mapping. For example, as shown in FIG. 2(a), the above 3 consecutive bits b 3t , b 3t+1 , b 3t+2 are mapped to the pilot symbol where b 3t and b 3t+1 are used to obtain the quadrant corresponding to the pilot symbol, and b 3t+2 is used to obtain the amplitude corresponding to the pilot symbol. The relationship between the values of the above 3 consecutive bits and the values of the pilot symbol is shown in Table 1-1a below.

[0351] Table 1-1a

[0352] In some specific implementations, the framing operation occurs before the dual polarization symbol mapping, as shown in Figures 2(b), 2(c), or 2(d), where the three consecutive bits b are... 3t b 3t+1 b 3t+2 The mapping is done to 4 bits, as shown in Table 1-1b below, which illustrates the correspondence between the values ​​of the three consecutive bits and the values ​​of the resulting 4 bits. These 4 bits are then symbol-mapped to obtain a pilot symbol, where 0000 is symbol-mapped to -A2-A2j, 0101 to -A1-A1j, 0010 to -A2+A2j, 0111 to -A1+A1j, 1010 to A2+A2j, 1111 to A1+A1j, 1000 to A2-A2j, and 1101 to A1-A1j.

[0353] Table 1-1b

[0354] It should be noted that "symbol mapping" in the embodiments of this application refers to the operation of mapping bits to symbols, such as using symbol mapping methods like DP-16QAM or DP-64QAM. Taking DP-16QAM as an example, 8 bits undergo dual-polarization symbol mapping to obtain 1 DP-16QAM symbol, that is, 4 bits undergo symbol mapping to obtain 16QAM symbol in the polarization direction. The aforementioned "bit sequence b0, b1, b2, ... b 3D-1 Every three consecutive bits are used to map one pilot symbol out of D pilot symbols, and "three consecutive bits b" 3t b 3t+1 b 3t+2The "mapping" in "mapping to 4 bits" is a concept different from "symbol mapping." Specifically, taking the scenario shown in Figure 2(a) as an example, the mapping of 3 consecutive bits from the 3×D bits acquired by PRBS to obtain one pilot symbol can be understood as determining the value of the pilot symbol corresponding to the value of the 3 consecutive bits by looking up table 1-1a. This operation of looking up table 1-1a based on the correspondence is "mapping," or it can also be called "3 consecutive bits corresponding to 1 pilot symbol." Taking the scenarios shown in Figures 2(b)-2(d) as examples, the mapping of 3 consecutive bits from the 3×D bits acquired by PRBS to obtain 4 bits can be understood as determining the value of the 4 bits corresponding to the value of the 3 consecutive bits by looking up table 1-1b. This operation of looking up table 1-1b based on the correspondence is "mapping," or it can also be called "3 consecutive bits corresponding to 4 bits." Then, these 4 bits undergo symbol mapping to obtain 1 pilot symbol. The terms "mapping" and "symbol mapping" appearing in similar embodiments below can be understood with reference to this description.

[0355] It should be noted that the framing operation occurs before the dual polarization symbol mapping, as shown in Figure 2(b), Figure 2(c), or Figure 2(d), where the three consecutive bits b are... 3t b 3t+1 b 3t+2 Four bits are obtained using the mapping rules shown in Table 1-1b. These four bits are then used for symbol mapping to obtain a pilot symbol. The obtained pilot symbol is mapped using the mapping rules shown in Table 1-1a. 3t b 3t+1 b 3t+2 The mapped pilot symbols are the same. Therefore, for simplicity, the embodiments of this application can combine Tables 1-1a and 1-1b as shown in Table 1-1 below. That is, Table 1-1 below is a complete correspondence table of 3 consecutive bits and their corresponding pilot symbols and 4 bits. For the schemes shown in Figures 2(a) to 2(d), they can all be implemented through Table 1-1. Therefore, Tables 1-2 to 3-2 provided later are complete correspondence tables similar to Table 1-1. Tables 1-2 to 3-2 can also be split into two tables in a similar way to Table 1-1a and Table 1-1b, to adapt to the scenarios shown in Figure 2(a) and Figures 2(b) to 2(d) respectively. They will not be described in detail below.

[0356] Table 1-1

[0357] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t and b 3t+1 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t+2 The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Table 1-2 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used to obtain the amplitude of the pilot symbol. 3t b 3t+1 b 3t+2 The mapping is done to 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-2 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 bits obtained by mapping.

[0358] Table 1-2

[0359] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t+1 and b 3t+2 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Tables 1-3 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used... 3t b 3t+1 b 3t+2 The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-3 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 bits obtained by mapping.

[0360] Table 1-3

[0361] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t+1 and b 3t+2 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3tThe values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Tables 1-4 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used to obtain the amplitude of the pilot symbol. 3t b 3t+1 b 3t+2 The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-4 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 mapped bits.

[0362] Table 1-4

[0363] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t and b 3t+2 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t+1 The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Tables 1-5 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used... 3t b 3t+1 b 3t+2 The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-5 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 mapped bits.

[0364] Table 1-5

[0365] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t and b 3t+2 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t+1 The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Tables 1-6 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used to obtain the amplitude of the pilot symbol. 3t b 3t+1 b 3t+2The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-6 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 bits obtained by mapping.

[0366] Table 1-6

[0367] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t and b 3t+1 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t+2 The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Tables 1-7 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used to obtain the amplitude of the pilot symbol. 3t b 3t+1 b 3t+2 The mapping is done to 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-7 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 bits obtained by mapping.

[0368] Table 1-7

[0369] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t and b 3t+1 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t+2 The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are shown in Table 1-8 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used to obtain the amplitude of the pilot symbol. 3t b 3t+1 b 3t+2 The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-8 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 mapped bits.

[0370] Table 1-8

[0371] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t+1 and b 3t+2 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Tables 1-9 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used... 3t b 3t+1 b 3t+2 The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-9 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 bits obtained by mapping.

[0372] Table 1-9

[0373] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t+1 and b 3t+2 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Table 1-10 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used to obtain the amplitude of the pilot symbol. 3t b 3t+1 b 3t+2 The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-10 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 bits obtained by mapping.

[0374] Table 1-10

[0375] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t and b 3t+2 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t+1 The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Table 1-11 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used to obtain the amplitude of the pilot symbol. 3t b 3t+1 b 3t+2 The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-11 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 bits obtained by mapping.

[0376] Table 1-11

[0377] In other specific applications, the above three consecutive bits b 3t b 3t+1 b 3t+2 Mapped to pilot symbols Where b 3t and b 3t+2 These two bits are used to obtain the quadrant corresponding to the pilot symbol, b 3t+1 The values ​​of the three consecutive bits used to obtain the amplitude corresponding to the pilot symbol are related to the values ​​of the pilot symbol as shown in Table 1-12 below. In some specific embodiments, the framing operation is performed before the dual polarization symbol mapping, and the three consecutive bits b are used to obtain the amplitude of the pilot symbol. 3t b 3t+1 b 3t+2 The mapping is to 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 1-12 below shows the relationship between the values ​​of the above 3 consecutive bits and the values ​​of the 4 mapped bits.

[0378] Table 1-12

[0379] It should be noted that by designing the coefficients a in the 11th-order polynomial 10The target polynomial and seed are determined by the values ​​of a1, or the coefficients a9…a1 in a 10th-order polynomial, or the coefficients a8…a1 in a 9th-order polynomial, or the coefficients a7…a1 in an 8th-order polynomial. This ensures that the real part sequence (also called the I-path) and the imaginary part sequence (also called the Q-path) of the generated pilot symbol sequences in the two polarization directions have good autocorrelation and cross-correlation characteristics. More specifically, the designed pilot symbol sequence in the X-polarization direction, the pilot symbol sequence in the X-polarization direction, the pilot symbol sequence in the Y-polarization direction, and the pilot symbol sequence in the Y-polarization direction, a total of four D-bit sequences, have good autocorrelation and cross-correlation characteristics, which is beneficial to improving the quality of the recovered signal at the receiving end.

[0380] It should be noted that, as shown in Figures 6(a)-6(d), the order of the target polynomial and the number of non-zero terms in the coefficients affect the complexity of the pilot symbol generation structure. In this embodiment, when designing the target polynomial, the order of the polynomial must be constrained to be no greater than 11, and the number of non-zero terms in the polynomial must be no greater than 8. When selecting a polynomial, the order and number of non-zero terms of the target polynomial should be minimized to reduce the complexity and power consumption of the pilot symbol generation structure. It should also be noted that, given a target polynomial, there may not be a seed that results in good autocorrelation and cross-correlation between the target polynomial and the pilot symbol sequence determined by the seed. Therefore, the selection of the target polynomial is not only about minimizing the order and the number of non-zero terms, but also about whether a corresponding seed can be selected to ensure good autocorrelation and cross-correlation characteristics of the generated pilot symbol sequence, as well as its real and imaginary parts, to improve the quality of the recovered signal at the receiving end.

[0381] In this embodiment, polynomials of order less than or equal to 11, particularly 8th, 9th, 10th, or 11th order polynomials, and mainly higher-order polynomials, are considered. These do not significantly improve the sequence autocorrelation and cross-correlation characteristics of the generated pilot symbols. Lower-order polynomials, such as 6th and 7th order polynomials, while having lower implementation complexity, typically produce pilot symbols with insufficient sequence autocorrelation and cross-correlation characteristics. Furthermore, polynomials with no more than 8 terms are considered, as they have lower hardware implementation complexity.

[0382] Secondly, the D pilot symbols in the X-polarization direction are generated by the target polynomial, the first seed, and the second seed in the X-polarization direction; the D pilot symbols in the Y-polarization direction are generated by the target polynomial, the third seed, and the fourth seed in the Y-polarization direction.

[0383] The target polynomial and the first seed in the X-polarization direction are used to obtain the quadrant of each pilot symbol among the D pilot symbols, that is, to determine whether the i-th pilot symbol is A1+A1j or A2+A2j in the first quadrant, -A1+A1j or -A2+A2j in the second quadrant, -A1-A1j or -A2-A2j in the third quadrant, or A1-A1j or A2-A2j in the fourth quadrant.

[0384] The target polynomial and the second seed in the X-polarization direction are used to obtain the amplitude of each pilot symbol in the D pilot symbols, that is, to determine whether the i-th pilot symbol is located in the inner circle as -A1-A1j, -A1+A1j, A1-A1j or A1+A1j, or located in the outer circle as -A2-A2j, -A2+A2j, A2-A2j or A2+A2j.

[0385] The target polynomial in the Y-polarization direction and the third seed in the Y-polarization direction are used to obtain the quadrant of each pilot symbol among the D pilot symbols, that is, to determine whether the i-th pilot symbol is A1+A1j or A2+A2j in the first quadrant, -A1+A1j or -A2+A2j in the second quadrant, -A1-A1j or -A2-A2j in the third quadrant, or A1-A1j or A2-A2j in the fourth quadrant.

[0386] The target polynomial in the Y-polarization direction and the fourth seed in the Y-polarization direction are used to obtain the amplitude of each pilot symbol in the D pilot symbols, that is, to determine whether the i-th pilot symbol is located in the inner circle as -A1-A1j, -A1+A1j, A1-A1j or A1+A1j, or located in the outer circle as -A2-A2j, -A2+A2j, A2-A2j or A2+A2j.

[0387] In this embodiment of the application, the same target generating polynomial can be used for pilot symbols in two orthogonal polarization directions. However, since the seeds used in the two polarization directions are different, the D pilot symbols obtained in the two polarization directions are not exactly the same.

[0388] Figure 7(a) is a schematic diagram of the fifth pilot symbol generation structure in the embodiments of this application. The target polynomial is a 10th-order polynomial: x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2+a1×x+1. Where a9…a1 can take values ​​of 0 or 1. In some specific applications, the number of non-zero terms in a9…a1 is no greater than 6, meaning the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8, resulting in lower hardware implementation complexity. As shown in Figure 7(a), the length of the first seed used to obtain the quadrant of each symbol in the X-polarization direction is 10 bits, and the length of the third seed used to obtain the quadrant of each symbol in the Y-polarization direction is 10 bits. The first or third seed can be represented in binary form as b9, b8, b7, b6, b5, b4, b3, b2, b1, b0. Of course, the seeds can also be represented in hexadecimal or decimal, but need to be converted to binary form when operating with the target polynomial. The second seed used to obtain the amplitude of each symbol in the X-polarization direction has a length of 10 bits, and the fourth seed used to obtain the amplitude of each symbol in the Y-polarization direction has a length of 10 bits. The second seed or the fourth seed can be represented in binary form as s9, s8, s7, s6, s5, s4, s3, s2, s1, s0.

[0389] Figure 7(b) is a schematic diagram of the sixth pilot symbol generation structure in this embodiment. The target polynomial is a 9th-order polynomial: x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1. Where a8…a1 can take values ​​of 0 or 1. In some specific applications, the number of non-zero terms in a8…a1 is no greater than 6, meaning the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8, resulting in lower hardware implementation complexity. As shown in Figure 7(b), the length of the first seed used to obtain the quadrant of each symbol in the X-polarization direction is 9 bits, and the length of the third seed used to obtain the quadrant of each symbol in the Y-polarization direction is 9 bits. The first or third seed can be represented in binary as b8, b7, b6, b5, b4, b3, b2, b1, b0. Of course, the seeds can also be represented in hexadecimal or decimal, but need to be converted to binary form when operating with the target polynomial. The length of the second seed used to obtain the amplitude of each symbol in the X-polarization direction is 9 bits, and the length of the fourth seed used to obtain the amplitude of each symbol in the Y-polarization direction is 9 bits, which can be represented in binary as s8, s7, s6, s5, s4, s3, s2, s1, s0.

[0390] In Figures 7(a) and 7(b), for a scenario requiring the generation of D pilot symbols in one polarization direction, a bit sequence b0, b1, b2, ... b, comprising 2 × D bits, is obtained based on the target polynomial and the first seed. 2D-1 Based on the objective polynomial and the second seed, a bit sequence s0, s1, s2, ... s is obtained, consisting of D bits. D-1 The bit sequence b0, b1, b2, ... b 2D-1 In every 2 consecutive bits b 2t b 2t+1 And bit sequence s0, s1, s2, ... s D-1 1 bit s in t A total of 3 bits b 2t b 2t+1 s t It is mapped to one pilot symbol out of D pilot symbols. The b 2t and b 2t+1 These two bits are used to obtain the quadrant corresponding to the pilot symbol, s t Used to obtain the amplitude corresponding to the pilot symbol.

[0391] In some specific applications, the above three bits b 2t b 2t+1 s t Mapped to pilot symbols The relationship between the values ​​of the above three bits and the values ​​of the pilot symbols is shown in Table 2-1 below. In some specific implementations, the framing operation is performed before the dual polarization symbol mapping, and the above three bits b 2t b 2t+1 s t The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 2-1 below shows the relationship between the values ​​of the 3 bits and the values ​​of the 4 bits obtained from the mapping.

[0392] Table 2-1

[0393] In other specific applications, the above three bits b 2t b 2t+1 s t Mapped to pilot symbols The relationship between the values ​​of the above three bits and the values ​​of the pilot symbols is shown in Table 2-2 below. In some specific implementations, the framing operation is performed before the dual polarization symbol mapping, and the above three bits b 2t b 2t+1 s tThe mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol. The rightmost column of Table 2-2 below shows the relationship between the values ​​of the 3 bits and the values ​​of the 4 bits obtained from the mapping.

[0394] Table 2-2

[0395] Thirdly, the D pilot symbols in the X-polarization direction are generated by the target polynomial, the first seed, and the second seed; the D pilot symbols in the Y-polarization direction are generated by the target polynomial, the second seed, and the third seed. Here, the same target polynomial is used for both the X-polarization and Y-polarization directions.

[0396] The target polynomial and the first seed are used to obtain the quadrant of each pilot symbol among the D pilot symbols in the X polarization direction, that is, to determine whether the i-th pilot symbol is A1+A1j or A2+A2j in the first quadrant, -A1+A1j or -A2+A2j in the second quadrant, -A1-A1j or -A2-A2j in the third quadrant, or A1-A1j or A2-A2j in the fourth quadrant.

[0397] The objective polynomial and the third seed are used to obtain the quadrant of each pilot symbol among the D pilot symbols in the Y polarization direction, that is, to determine whether the i-th pilot symbol is A1+A1j or A2+A2j in the first quadrant, -A1+A1j or -A2+A2j in the second quadrant, -A1-A1j or -A2-A2j in the third quadrant, or A1-A1j or A2-A2j in the fourth quadrant.

[0398] The objective polynomial and the second seed are used to obtain the amplitude of each pilot symbol among the D pilot symbols in the X-polarization direction, that is, to determine whether the i-th pilot symbol in the X-polarization direction is located in the inner circle as -A1-A1j, -A1+A1j, A1-A1j, or A1+A1j, or located in the outer circle as -A2-A2j, -A2+A2j, A2-A2j, or A2+A2j. The objective polynomial and the second seed are also used to obtain the amplitude of each pilot symbol among the D pilot symbols in the Y-polarization direction, that is, to determine whether the i-th pilot symbol in the Y-polarization direction is located in the inner circle as -A1-A1j, -A1+A1j, A1-A1j, or A1+A1j, or located in the outer circle as -A2-A2j, -A2+A2j, A2-A2j, or A2+A2j.

[0399] Figure 8(a) is a schematic diagram of the seventh pilot symbol generation structure in the embodiments of this application. The target polynomial is a 10th-order polynomial: x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1. Where a9…a1 can take values ​​of 0 or 1. In some specific applications, the number of non-zero terms in a9…a1 is no greater than 6, meaning the number of terms in the objective polynomial is greater than or equal to 2 and less than or equal to 8, resulting in lower hardware implementation complexity. As shown in Figure 8(a), the length of the first seed used to obtain the quadrant of each symbol in the X-polarization direction is 10 bits, which can be represented in binary form as: The third seed, used to obtain the quadrant of each symbol in the Y-polarization direction, is 10 bits long and can be represented in binary form as follows: Of course, the seed can also be represented in hexadecimal or decimal, but it needs to be converted to binary form when operating with the target polynomial. The second seed, used to obtain the amplitude of each symbol in the X-polarization direction and the Y-polarization direction, is 10 bits long and can be represented in binary as s9, s8, s7, s6, s5, s4, s3, s2, s1, s0.

[0400] Figure 8(b) is a schematic diagram of the eighth pilot symbol generation structure in this embodiment. The target polynomial is a 9th-order polynomial: x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1. Where a8…a1 can take values ​​of 0 or 1. In some specific applications, the number of non-zero terms in a8…a1 is no greater than 6, meaning the number of terms in the objective polynomial is greater than or equal to 2 and less than or equal to 8, resulting in lower hardware implementation complexity. As shown in Figure 8(b), the length of the first seed used to obtain the quadrant of each symbol in the X-polarization direction is 9 bits, which can be represented in binary form as: The third seed used to obtain the quadrant of each sign in the Y-polarization direction is 9 bits long, which can be represented in binary form as follows: Of course, the seed can also be represented in hexadecimal or decimal, but it needs to be converted to binary form when operating with the target polynomial. The second seed, used to obtain the amplitude of each symbol in the X-polarization direction and the Y-polarization direction, is 9 bits long and can be represented in binary as s8, s7, s6, s5, s4, s3, s2, s1, s0.

[0401] In Figures 8(a) and 8(b), for the scenario requiring the generation of D dual-polarization pilot symbols, a bit sequence comprising 2×D bits is obtained based on the target polynomial and the first seed. Obtain a bit sequence consisting of 2×D bits based on the objective polynomial and the third seed. Based on the objective polynomial and the second seed, obtain a bit sequence s0, s1, s2, ... s0 consisting of 2 × D bits. 2D-1 .

[0402] In the X-polarization direction, the bit sequence Every 2 consecutive bits And bit sequence s0, s1, s2, ... s 2D-1 One of the bits s in 2t A total of 3 bits s 2t It is mapped to one pilot symbol out of D pilot symbols. and These two bits are used to obtain the quadrant corresponding to the pilot symbol, s 2t Used to obtain the amplitude corresponding to the pilot symbol.

[0403] In the Y-polarization direction, the bit sequence Every 2 consecutive bits And bit sequence s0, s1, s2, ... s 2D-1 The other bit s in 2t+1 A total of 3 bits s 2t+1 It is mapped to one pilot symbol out of D pilot symbols. and These two bits are used to obtain the quadrant corresponding to the pilot symbol, s 2t+1 Used to obtain the amplitude corresponding to the pilot symbol.

[0404] In some specific applications, the above 3 bits s 2t Mapped to pilot symbols The above 3 bits s 2t+1 Mapped to pilot symbols The relationship between the values ​​of the above three bits and the values ​​of the pilot symbols is shown in Table 3-1 below. In some specific implementations, the framing operation is performed before the dual polarization symbol mapping, and the above three bits... s 2t The mapping is 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol in the X-polarization direction; the above 3 bits s 2t+1The data is mapped to 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol in the Y-polarization direction. The rightmost column of Table 3-1 below shows the relationship between the values ​​of the 3 bits and the values ​​of the 4 bits obtained from the mapping.

[0405] Table 3-1

[0406] In other specific applications, the above three bits s 2t Mapped to pilot symbols The above 3 bits s 2t+1 Mapped to pilot symbols The relationship between the values ​​of the above three bits and the values ​​of the pilot symbols is shown in Table 3-2 below. In some specific implementations, the framing operation is performed before the dual polarization symbol mapping, and the above three bits... s 2t The mapping is done to 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol in the Y-polarization direction; the above 3 bits s 2t+1 The data is mapped to 4 bits, and these 4 bits are then symbol-mapped to obtain a pilot symbol in the Y-polarization direction. The rightmost column of Table 3-2 below shows the relationship between the values ​​of the 3 bits and the values ​​of the 4 bits obtained from the mapping.

[0407] Table 3-2

[0408] 102. The sending end sends a data frame to the receiving end.

[0409] The data frames sent by the transmitting end will be transmitted to the receiving end through the channel. In some possible scenarios, the dual-polarization symbols in the data frame will be converted from digital to analog (DAC) to obtain four analog signals, corresponding to the I component signal in the X polarization direction, the Q component signal in the X polarization direction, the I component signal in the Y polarization direction, and the Q component signal in the Y polarization direction, respectively, and then transmitted to the receiving end through optical fiber.

[0410] 103. The receiving end performs signal processing on the received data frames.

[0411] It should be understood that the data frame received by the receiving end has been transmitted through the channel, which can be understood as a distorted signal affected by noise or other impairments in the channel. That is, the data frame received by the receiving end is different from the data frame sent by the transmitting end. For example, the data frame received by the receiving end is not aligned with the data frame sent by the transmitting end, and the receiving end needs to perform frame synchronization based on the pilot symbols. The specific operations performed by the receiving end after receiving the data frame will not be described in detail in this application. For details, please refer to the system structure diagram shown in Figure 1. For example, the receiving end DSP processor performs signal processing on the received data frame, including dispersion compensation, synchronization, and phase recovery.

[0412] It should be noted that the data frame designed in this embodiment only contains pilot symbols and payload symbols (also known as pre-framing symbols). In the corresponding receiver processing, the pilot symbols are used not only to assist in carrier phase recovery but also to distinguish the two polarization directions and for frame synchronization. The receiver obtains four data streams, namely X... I Component data stream, X Q Component data stream, Y I Component data stream, Y Q For component data streams, pilot symbols are needed to distinguish the real or imaginary part sequence in the X-polarization or Y-polarization direction of each data stream.

[0413] The following are some specific implementation examples.

[0414] Example 1: Figure 9 is a schematic diagram of another data frame structure in this embodiment. Taking DP-16QAM modulation as an example, 96 × 63 = 6048 dual-polarization payload symbols (pre-framing dual-polarization symbols) are obtained through BCH(126,110) encoding and DP-16QAM modulation. One pilot symbol is inserted before every 63 symbols in the 6048 payload symbols, for a total of 96 pilot symbols, resulting in the data frame (also called a DSP frame) structure shown in Figure 9, i.e., N = 6144, M = 64, D = 96. In both the X-polarization and Y-polarization directions, the probability of the pre-framing symbol taking the value of one of the 16 symbols in the 16QAM constellation is the same. In either the X-polarization or Y-polarization direction, the total number of pilot symbols located within the inner circle of the 16QAM constellation diagram (i.e., those with values ​​of -A1-A1j, -A1+A1j, A1-A1j, or A1+A1j) out of the 96 pilot symbols is 48. Similarly, the total number of pilot symbols located within the outer circle of the 16QAM constellation diagram (i.e., those with values ​​of -A2-A2j, -A2+A2j, A2-A2j, or A2+A2j) out of the 96 pilot symbols is also 48. In this case, the average energy of the 96 pilot symbols is the same as the average energy of the symbols before framing, and the transmission performance cost caused by D pilot symbols is relatively low.

[0415] As an example, the number of pilot symbols with values ​​of -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j are all 12, and the number of pilot symbols with values ​​of -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j are also 12. In this case, the sequence of pilot symbols in each polarization direction achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiving end.

[0416] Example 2: Based on Example 1, in either the X-polarization or Y-polarization direction, the number of pilot symbols with values ​​of -A1-A1j is d1=11, the number with values ​​of -A1+A1j is d2=13, the number with values ​​of A1-A1j is d3=13, and the number with values ​​of A1+A1j is d4=11; the number of pilot symbols with values ​​of -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j are all 12. In this case, the sequence of pilot symbols in each polarization direction achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiver. Moreover, the average energy of the 96 pilot symbols is the same as the average energy of the symbols before framing, and the transmission performance cost caused by D pilot symbols is relatively low.

[0417] Example 3: Based on Example 1, in the X-polarization direction, among the 96 pilot symbols, the number of values ​​of -A1-A1j is d1=11, the number of values ​​of -A1+A1j is d2=13, the number of values ​​of A1-A1j is d3=13, and the number of values ​​of A1+A1j is d4=11; among the 96 pilot symbols, the number of values ​​of -A2-A2j is d5=11, the number of values ​​of -A2+A2j is d6=13, the number of values ​​of A2-A2j is d7=13, and the number of values ​​of A2+A2j is d8=11. In the Y-polarization direction, among the 96 pilot symbols, the number of symbols with values ​​of -A1-A1j is d1=13, the number with values ​​of -A1+A1j is d2=11, the number with values ​​of A1-A1j is d3=11, and the number with values ​​of A1+A1j is d4=13; among the 96 pilot symbols, the number of symbols with values ​​of -A2-A2j is d5=13, the number with values ​​of -A2+A2j is d6=11, the number with values ​​of A2-A2j is d7=11, and the number with values ​​of A2+A2j is d8=13. At this point, the sequence of pilot symbols in each polarization direction achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiver. Moreover, the average energy of the 96 pilot symbols is the same as the average energy of the symbols before framing, and the transmission performance cost caused by D pilot symbols is relatively low. It should also be noted that, in both the X and Y polarization directions, among the 192 pilot symbols of the 96 dual-polarization pilot symbols, the number of values ​​for -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j is D / 4 = 24, which effectively ensures that the number of symbols is close to balanced, which is beneficial to improving the quality of the signal recovered by the receiver.

[0418] Example 4: Taking the data frame (DSP frame) structure and DP-16QAM modulation in Figure 9 as an example, the 96 × 63 = 6048 dual-polarization payload symbols (pre-frame dual-polarization symbols) are obtained through BCH(126,110) encoding and DP-16QAM modulation. One pilot symbol is inserted before every 63 symbols in the 6048 payload symbols, for a total of 96 pilot symbols, resulting in the data frame (DSP frame) structure shown in Figure 9, i.e., N = 6144, M = 64, D = 96. In both the X-polarization and Y-polarization directions, the probability of the pre-frame symbol taking the value of one of the 16 symbols in the 16QAM constellation is the same. The 96 pilot symbols in both the X-polarization and Y-polarization directions are shown in Table 4. In Table 4, p... i and q i Let i be a real number, such that the 96 pilot symbols are all points on the outermost or innermost ring of the 16QAM constellation, where 1≤i≤96.

[0419] When the 16 constellation points (also called symbols) on the adopted 16QAM constellation diagram are set to {±1±1j, ±1±3j, ±3±1j, ±3±3j}, the values ​​of pi and qi are either 1 or 3. When the 16 symbols on the adopted 16QAM constellation diagram are set to... When, the values ​​of pi and qi are... or By selecting specific values ​​for 96 real numbers pi and 96 real numbers qi, the sequence of 96 pilot symbols in each polarization direction achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiver. Furthermore, by selecting specific values ​​for 96 real numbers pi and qi, the number of pilot symbols in each polarization direction located in the inner circle of the constellation diagram is 48, and the number located in the outer circle is 48. In this case, the average energy is the same as the average energy of the symbols before framing, and the transmission performance cost caused by D pilot symbols is relatively low.

[0420] Table 4

[0421] It should be understood that Table 4 gives 96 pilot symbols in the X-polarization direction, with real numbers p i The value q is used to set whether the i-th pilot symbol is an inner or outer ring symbol in the constellation diagram. Table 4 lists the 96 pilot symbols in the Y-polarization direction, with the real number q... i The value is used to set whether the i-th pilot symbol is an inner ring symbol or an outer ring symbol in the constellation diagram. For example, as shown in example (a) of Figure 5, when the real number p i (or real number q) i When the value is 1, the i-th pilot symbol in the X-polarization direction (or Y-polarization direction) takes the value of one of the inner circle symbols -1-1j, -1+1j, 1-1j, and 1+1j; when the real number p i (or real number q) i When the value is 3, the i-th pilot symbol in the X-polarization direction (or Y-polarization direction) is one of the outer ring symbols -3-3j, -3+3j, 3-3j and 3+3j.

[0422] Table 4 lists 96 pilot symbols in the X-polarization direction, with the real number p... i Setting all values ​​to 3 yields 96 complex numbers. These 96 complex numbers represent the 96 pilot symbols in the X-polarization direction used by the existing 800LR; the 96 pilot symbols in the Y-polarization direction are represented by the real number q. i Setting all values ​​to 3 yields 96 complex numbers, which represent the 96 pilot symbols in the Y-polarization direction currently used by the 800LR. It should be understood that the quadrants of the 96 pilot symbols in the X-polarization direction on the constellation diagram are determined by the target polynomial x. 9 +x8 +x 5 +x 4 +1 and the first seed 0x175 are generated, and the 96 pilot symbols in the Y-polarization direction are located in the quadrants of the constellation diagram by the target polynomial x. 9 +x 8 +x 5 +x 4 +1 and the third seed 0x03D are generated. That is, the 96 pilot symbols given in this embodiment 4 are well compatible with the existing 800LR scenario, which is beneficial to hardware implementation. In particular, when the solution of this embodiment is applied to the 1.6T transmission scenario, it can make the receiving DSP processor well compatible with 1.6T transmission and existing 800LR transmission, with low overall power consumption and complexity.

[0423] Example 5: Based on Example 4, this example provides a more specific set of values ​​for the 96 pilot symbols.

[0424] Figure 10 is a schematic diagram of an embodiment of generating pilot symbols according to this application. As shown in Figure 10, the quadrants of the D=96 pilot symbols in the X-polarization direction on the constellation diagram are generated by the target polynomial x. 9 +x 8 +x 5 +x 4 +1 and the first seed 0x175 are generated, and the amplitudes of the 96 pilot symbols in the X-polarization direction on the constellation diagram are generated by the target polynomial x. 9 +x 8 +x 5 +x 4 +1 and the second seed 0x169 are generated. Based on the objective polynomial and the first seed, a continuous bit sequence b0, b1, b2, ... b is obtained with a bit length of 192. 191 Based on the objective polynomial and the second seed, a continuous bit sequence s0, s1, s2, ... s is obtained with a length of 96 bits. 95 The bit sequence b0, b1, b2, ... b 191 In every 2 consecutive bits b 2t b 2t+1 And bit sequence s0, s1, s2, ... s 95 1 bit s in t A total of 3 bits b 2t b 2t+1 s t It is mapped to a pilot symbol in the X-polarization direction.

[0425] The quadrants of the constellation diagram for the D=96 pilot symbols in the Y-polarization direction are determined by the target polynomial x. 9 +x 8 +x 5 +x4 +1 and the third seed 0x03D are generated. The amplitudes of the 96 pilot symbols in the Y-polarization direction on the constellation diagram are generated by the target polynomial x. 9 +x 8 +x 5 +x 4 +1 and the fourth seed 0x071 are used to generate a continuous bit sequence b0, b1, b2, ... b with a length of 192 bits, obtained based on the objective polynomial and the third seed. 191 Based on the objective polynomial and the fourth seed, a continuous bit sequence s0, s1, s2, ... s is obtained with a length of 96 bits. 95 The bit sequence b0, b1, b2, ... b 191 In every 2 consecutive bits b 2t b 2t+1 And bit sequence s0, s1, s2, ... s 95 1 bit s in t A total of 3 bits b 2t b 2t+1 s t It is mapped to a pilot symbol in the Y-polarization direction.

[0426] In this embodiment of the application, the mapping method shown in Table 2-1 is used as an example, namely s t When =0, the pilot symbol is located in the inner circle of the constellation diagram, s t When A1 = 1, the pilot symbol is located on the outer ring of the constellation diagram. In the X-polarization or Y-polarization direction, there are 96 pilot symbols as shown in Table 5, where A1 = 1 and A2 = 3.

[0427] Table 5

[0428] It should be noted that, on the one hand, in the X-polarization direction, the total number of pilot symbols located in the inner circle of the 16QAM constellation diagram is 48, of which the number of values ​​-A1-A1j, -A1+A1j, A1-A1j, and A1+A1j are all 12; on the other hand, the total number of pilot symbols located in the outer circle of the 16QAM constellation diagram is 48, of which the number of values ​​-A2-A2j, -A2+A2j, A2-A2j, and A2+A2j are all 12. On the other hand, in the Y-polarization direction, the total number of pilot symbols located in the inner circle of the 16QAM constellation diagram is 48, with the values ​​-A1-A1j, -A1+A1j, A1-A1j, and A1+A1j being 13, 11, 11, and 13 respectively; the total number of pilot symbols located in the outer circle of the 16QAM constellation diagram is 48, with the values ​​-A2-A2j, -A2+A2j, A2-A2j, and A2+A2j being 12 each.

[0429] It should be understood that in the X-polarization or Y-polarization direction, the average energy of the 96 pilot symbols is the same as the average energy of the symbols before framing, and the transmission performance cost caused by D pilot symbols is relatively low. The number of 96 pilot symbols in each polarization direction approaches equilibrium among the 8 possible symbols, and the sequence formed by the 96 pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiver.

[0430] Figure 11 is a schematic diagram reflecting the autocorrelation and cross-correlation characteristics in an embodiment of this application. As shown in Figure 11, the horizontal axis represents the offset (unit: number of symbols), and the vertical axis represents the normalized amplitude. The real part of the pilot symbol sequence in the X-polarization direction is denoted as (X_I), the imaginary part is denoted as (X_Q), the real part is denoted as (Y_I), and the imaginary part is denoted as (Y_Q). Example (a) in Figure 11 shows the periodic autocorrelation results of the real part (X_I), imaginary part (X_Q), real part (Y_I), and imaginary part (Y_Q) sequences in the X-polarization direction. Example 11(b) shows the periodic cross-correlation results of the real part sequence in the X-polarization direction with the real part sequence in the Y-polarization direction (X_I&Y_I), the real part sequence in the X-polarization direction with the imaginary part sequence in the X-polarization direction (X_I&X_Q), the real part sequence in the X-polarization direction with the imaginary part sequence in the Y-polarization direction (X_I&Y_Q), the imaginary part sequence in the X-polarization direction with the real part sequence in the Y-polarization direction (X_Q&Y_I), the real part sequence in the Y-polarization direction with the imaginary part sequence in the Y-polarization direction (Y_I&Y_Q), and the imaginary part sequence in the X-polarization direction with the imaginary part sequence in the Y-polarization direction (X_Q&Y_Q). The absolute values ​​of the sidelobe values ​​of the periodic autocorrelation function and the normalized amplitude of the periodic cross-correlation function are all no greater than 0.3.

[0431] The receiver uses pilot sequences to perform DSP (Digital Signal Processing) to recover the signal based on the received signals in the two polarization directions. For example, by calculating the correlation values ​​between the real and imaginary parts of the received signal and the pilot sequences in the X-polarization direction, and the correlation values ​​between the real and imaginary parts of the received signal and the pilot sequences in the Y-polarization direction, the real and imaginary parts in the X / Y polarization directions can be distinguished, and frame synchronization alignment can be performed. Simultaneously, carrier phase recovery is performed using the pilot sequences. The designed pilot sequences exhibit good autocorrelation and cross-correlation characteristics, satisfy DC balance, and are beneficial for improving the quality of the recovered signal at the receiver.

[0432] Example 6: Based on Example 5, this example provides an equivalent generation method for the 96 pilot symbols.

[0433] Figure 12 is a schematic diagram of another implementation method for generating pilot symbols in this application. Taking the framing operation before symbol mapping as an example, as shown in Figure 12, the quadrants of the 96 pilot symbols in the X-polarization direction on the constellation diagram are generated by the target polynomial x. 9 +x 8 +x 5 +x 4 +1 and the first seed 0x175 are generated, and the amplitudes of the 96 pilot symbols in the X-polarization direction on the constellation diagram are generated by the target polynomial x. 9 +x 8 +x 5 +x 4 +1 and the second seed 0x169 are generated. A bit sequence b0, b1, b2, ... b, consisting of 192 bits, is obtained based on the objective polynomial and the first seed. 191 Based on the objective polynomial and the second seed, a bit sequence s0, s1, s2, ... s is obtained, consisting of 96 bits. 95 The bit sequence b0, b1, b2, ... b 191 In every 2 consecutive bits b 2t b 2t+1 And bit sequence s0, s1, s2, ... s Q-1 1 bit s in t A total of 3 bits b 2t b 2t+1 s t The mapping is to the 4 bits of the output.

[0434] The 96 pilot symbols in the Y-polarization direction are located in quadrants of the constellation diagram by the target polynomial x. 9 +x 8 +x 5 +x 4 +1 and the third seed 0x03D are generated. The amplitudes of the 96 pilot symbols in the Y-polarization direction on the constellation diagram are generated by the target polynomial x. 9 +x 8 +x 5 +x 4 +1 and the fourth seed 0x071 are used to generate the bit sequence b0, b1, b2, ... b, which consists of 92 bits, based on the objective polynomial and the third seed. 191 Based on the objective polynomial and the fourth seed, a bit sequence s0, s1, s2, ... s is obtained, consisting of 96 bits. 95 The bit sequence b0, b1, b2, ... b 191 In every 2 consecutive bits b 2t b 2t+1 And bit sequence s0, s1, s2, ... s 95 1 bit s in t A total of 3 bits b 2tb 2t+1 s t The mapping is to output 4 bits.

[0435] It should be noted that the four bits of the output obtained in the X-polarization direction or the Y-polarization direction are one of 0000, 0101, 0010, 0111, 1010, 1111, 1000, and 1101. These four bits of the output are mapped using 16QAM symbols to obtain one of the following pilot symbols: -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j. More specifically, the four bits of the output are mapped as follows: 0000 to -3-3j, 0101 to -1-1j, 0010 to -3+3j, 0111 to -1+1j, 1010 to 3+3j, 1111 to 1+1j, 1000 to 3-3j, and 1101 to 1-1j.

[0436] Example 7: Based on Example 4, this example provides another more specific set of values ​​for the 96 pilot symbols.

[0437] Figure 13 is a schematic diagram of another implementation method for generating pilot symbols in this application. As shown in Figure 13, with the target polynomial being x... 10 +x 9 +x 8 +x 5 Taking +1 as an example, a bit sequence of 192 bits is obtained based on the target polynomial and the first seed 0x14D. Based on the objective polynomial and the third seed 0x229, a bit sequence of length 192 bits is obtained. Based on the objective polynomial and the second seed 0x152, a bit sequence s0, s1, s2, ... s is obtained, consisting of 192 bits. 191 Bit sequence Every 2 consecutive bits And bit sequence s0, s1, s2, ... s 191 One of the bits s in 2t A total of 3 bits s 2t The bit sequence is mapped to one of the following pilot symbols: -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as a pilot symbol in the X-polarization direction. Every 2 consecutive bits And bit sequence s0, s1, s2, ... s 191 The other bit s in 2t+1A total of 3 bits s 2t+1 It is mapped to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as a pilot symbol in the Y-polarization direction.

[0438] In this embodiment of the application, the mapping method shown in Table 3-1 is used as an example, namely s t When =0, the pilot symbol is located in the inner circle of the constellation diagram, s t When A1 = 1, the pilot symbol is located on the outer ring of the constellation diagram. In the X-polarization or Y-polarization direction, there are 96 pilot symbols as shown in Table 6, where A1 = 1 and A2 = 3.

[0439] Table 6

[0440] It should be noted that, on the one hand, in the X-polarization direction, the total number of pilot symbols located in the inner circle of the 16QAM constellation diagram is 48, with 12 of each value being -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j; on the other hand, the total number of pilot symbols located in the outer circle of the 16QAM constellation diagram is 48, with 11, 13, 13, and 11 of each value being -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j. On the other hand, in the Y-polarization direction, the total number of pilot symbols located in the inner circle of the 16QAM constellation diagram is 48, with 12 of each value being -A1-A1j, -A1+A1j, A1-A1j, and A1+A1j; the total number of pilot symbols located in the outer circle of the 16QAM constellation diagram is 48, with 11, 13, 13, and 11 of each value being -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j.

[0441] It should be understood that in the X-polarization or Y-polarization direction, the average energy of the 96 pilot symbols is the same as the average energy of the symbols before framing, and the transmission performance cost caused by D pilot symbols is relatively low. The number of 96 pilot symbols in each polarization direction approaches equilibrium among the 8 possible symbols, and the sequence formed by the 96 pilot symbols achieves DC balance, which is beneficial to improving the quality of the recovered signal at the receiver.

[0442] The receiver uses the pilot sequence to recover the signal via DSP based on the received signals from the two polarization directions. For example, by calculating the correlation values ​​between the real and imaginary parts of the received signal and the pilot sequence in the X-polarization direction, and the correlation values ​​between the real and imaginary parts of the received signal and the pilot sequence in the Y-polarization direction, the real and imaginary parts in the X / Y polarization directions can be distinguished, and frame synchronization alignment can be performed. Simultaneously, carrier phase recovery is performed using the pilot signal. The designed pilot symbols exhibit good correlation characteristics, with normalized absolute values ​​of the sidelobe values ​​of the periodic autocorrelation function not exceeding 0.24 and normalized absolute values ​​of the periodic cross-correlation function not exceeding 0.275. This satisfies DC balance and improves the quality of the recovered signal at the receiver.

[0443] Example 8: Based on Example 4, an additional 96 pilot symbols are provided.

[0444] The quadrants of the D=96 pilot symbols in the X-polarization direction on the constellation diagram are generated by the target polynomial and the first seed. The amplitudes of the 96 pilot symbols in the X-polarization direction on the constellation diagram are generated by the target polynomial and the second seed. A bit sequence b0, b1, b2, ... b, comprising 192 bits, is obtained based on the target polynomial and the first seed. 191 Based on the objective polynomial and the second seed, a bit sequence s0, s1, s2, ... s is obtained, consisting of 96 bits. 95 The bit sequence b0, b1, b2, ... b 191 In every 2 consecutive bits b 2t b 2t+1 And bit sequence s0, s1, s2, ... s 95 1 bit s in t A total of 3 bits b 2t b 2t+1 s t It is mapped to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as a pilot symbol in the X-polarization direction.

[0445] The quadrants of the D=96 pilot symbols in the Y-polarization direction on the constellation diagram are generated by the target polynomial and the third seed. The amplitudes of the 96 pilot symbols in the Y-polarization direction on the constellation diagram are generated by the target polynomial and the fourth seed. A bit sequence b0, b1, b2, ... b, comprising 192 bits, is obtained based on the target polynomial and the third seed. 191 Based on the objective polynomial and the fourth seed, a bit sequence s0, s1, s2, ... s is obtained, consisting of 96 bits. 95 The bit sequence b0, b1, b2, ... b 191 In every 2 consecutive bits b2t b 2t+1 And bit sequence s0, s1, s2, ... s 95 1 bit s in t A total of 3 bits b 2t b 2t+1 s t It is mapped to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as a pilot symbol in the Y-polarization direction.

[0446] In this embodiment, the mapping method shown in Table 2-1 is used as an example, that is, s t When =0, the pilot symbol is located in the inner circle of the constellation diagram, s t When =1, the pilot symbol is located on the outer ring of the constellation diagram. The combination of the target polynomial, first seed, second seed, third seed, and fourth seed is shown in one row of the table below.

[0447] Table 7

[0448] Example 9: Based on Example 4, an additional 96 pilot symbols are provided.

[0449] The quadrants of the D=96 pilot symbols in the X-polarization direction on the constellation diagram are generated by the target polynomial and the first seed. The amplitudes of the 96 pilot symbols in the X-polarization direction on the constellation diagram are generated by the target polynomial and the second seed. A bit sequence b0, b1, b2, ... b, comprising 192 bits, is obtained based on the target polynomial and the first seed. 191 Based on the objective polynomial and the second seed, a bit sequence s0, s1, s2, ... s is obtained, consisting of 96 bits. 95 The bit sequence b0, b1, b2, ... b 191 In every 2 consecutive bits b 2t b 2t+1 And bit sequence s0, s1, s2, ... s 95 1 bit s in t A total of 3 bits b 2t b 2t+1 s t The pilot symbol is mapped to one of the following: -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as the pilot symbol for the X-polarization direction.

[0450] The quadrants of the D=96 pilot symbols in the Y-polarization direction on the constellation diagram are generated by the target polynomial and the third seed. The amplitudes of the 96 pilot symbols in the Y-polarization direction on the constellation diagram are generated by the target polynomial and the fourth seed. A bit sequence b0, b1, b2, ... b, comprising 192 bits, is obtained based on the target polynomial and the third seed. 191 Based on the objective polynomial and the fourth seed, a bit sequence s0, s1, s2, ... s is obtained, consisting of 96 bits. 95 The bit sequence b0, b1, b2, ... b 191 In every 2 consecutive bits b 2t b 2t+1 And bit sequence s0, s1, s2, ... s 95 1 bit s in t A total of 3 bits b 2t b 2t+1 s t The symbol is mapped to one of the following pilot symbols: -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as the pilot symbol for the Y-polarization direction.

[0451] In this embodiment, the mapping method shown in Table 2-2 is used as an example, that is, s t When =0, the pilot symbol is located on the outer ring of the constellation diagram, s t When =1, the pilot symbol is located in the inner circle of the constellation diagram. The combination of the target polynomial, first seed, second seed, third seed, and fourth seed is shown in one row of the table below.

[0452] Table 8

[0453] Example 10: Based on Example 4, more pilot symbols with D=96 are given.

[0454] Obtain a bit sequence consisting of 2×D bits based on the objective polynomial and the first seed. Obtain a bit sequence consisting of 2×D bits based on the objective polynomial and the third seed. Based on the objective polynomial and the second seed, obtain a bit sequence s0, s1, s2, ... s0 consisting of 2 × D bits. 2D-1 .

[0455] bit sequence Every 2 consecutive bits And bit sequence s0, s1, s2, ... s 2D-1 One of the bits s in 2t A total of 3 bits s 2tIt is mapped to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as a pilot symbol in the X-polarization direction.

[0456] bit sequence Every 2 consecutive bits And bit sequence s0, s1, s2, ... s 2D-1 The other bit s in 2t+1 A total of 3 bits s 2t+1 It is mapped to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as a pilot symbol in the Y-polarization direction.

[0457] In this embodiment, the mapping method shown in Table 3-1 is used as an example, that is, s 2t (or s) 2t+1 When ) is 0, the pilot symbol is located in the inner circle of the constellation diagram, s 2t (or s) 2t+1 When ), the pilot symbol is located on the outer ring of the constellation diagram. The combination of the target polynomial, the first seed, the second seed, and the third seed is shown in one row of the table below.

[0458] Table 9

[0459] Example 11: Based on Example 4, more pilot symbols with D=96 are given.

[0460] Obtain a bit sequence consisting of 2×D bits based on the objective polynomial and the first seed. Obtain a bit sequence consisting of 2×D bits based on the objective polynomial and the third seed. Based on the objective polynomial and the second seed, obtain a bit sequence s0, s1, s2, ... s0 consisting of 2 × D bits. 2D-1 .

[0461] bit sequence Every 2 consecutive bits And bit sequence s0, s1, s2, ... s 2D-1 One of the bits s in 2t A total of 3 bits s 2tIt is mapped to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as a pilot symbol in the X-polarization direction.

[0462] bit sequence Every two consecutive bits And bit sequence s0, s1, s2, ... s 2D-1 The other bit s in 2t+1 A total of 3 bits s 2t+1 It is mapped to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j, serving as a pilot symbol in the Y-polarization direction.

[0463] In this embodiment, the mapping method shown in Table 3-2 is used as an example, that is, s 2t (or s) 2t+1 When ) is 0, the pilot symbol is located on the outer ring of the constellation diagram, s 2t (or s) 2t+1 When ), the pilot symbol is located in the inner circle of the constellation diagram. The combination of the target polynomial, the first seed, the second seed, and the third seed is shown in one row of the table below.

[0464] Table 10

[0465] Example 12: Based on Example 4, an additional 96 pilot symbols are provided.

[0466] Based on the objective polynomial and the seed, obtain a bit sequence b0, b1, b2, ... b0, consisting of 3 × D = 288 bits. 287 The bit sequence b0, b1, b2, ... b 287 every 3 consecutive bits b 3t b 3t+1 b 3t+2 The mapping is to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j.

[0467] In this embodiment, taking the mapping method shown in Table 1-1 as an example, the combination of the target polynomial, the first seed, and the second seed is one of the rows in the table below.

[0468] Table 11

[0469] Example 13: Based on Example 4, an additional 96 pilot symbols are provided.

[0470] Based on the objective polynomial and the seed, obtain a bit sequence b0, b1, b2, ... b0, consisting of 3 × D = 288 bits. 287 The bit sequence b0, b1, b2, ... b 287 every 3 consecutive bits b 3t b 3t+1 b 3t+2 The mapping is to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j.

[0471] In this embodiment, taking the mapping method shown in Table 1-5 as an example, the combination of the target polynomial, the first seed, and the second seed is one of the rows in the table below.

[0472] Table 12

[0473] Example 14: Based on Example 4, an additional 96 pilot symbols are provided.

[0474] Based on the objective polynomial and the seed, obtain a bit sequence b0, b1, b2, ... b0, consisting of 3 × D = 288 bits. 287 The bit sequence b0, b1, b2, ... b 287 every 3 consecutive bits b 3t b 3t+1 b 3t+2 The mapping is to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j.

[0475] In this embodiment, taking the mapping method shown in Table 1-3 as an example, the combination of the target polynomial, the first seed, and the second seed is one of the rows in the table below.

[0476] Table 13

[0477] Example 15: Based on Example 4, an additional 96 pilot symbols are provided.

[0478] Based on the objective polynomial and the seed, obtain a bit sequence b0, b1, b2, ... b0, consisting of 3 × D = 288 bits. 287 The bit sequence b0, b1, b2, ... b 287 every 3 consecutive bits b 3tb 3t+1 b 3t+2 The mapping is to one of the pilot symbols -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j, and A2+A2j.

[0479] In this embodiment, taking the mapping method shown in Table 1-11 as an example, the combination of the target polynomial, the first seed, and the second seed is one of the rows in the table below.

[0480] Table 14

[0481] Figure 14 is a schematic diagram of a data transmission device according to an embodiment of this application. This data transmission device is applied at the transmitting end. As shown in Figure 14, the data transmission device includes a processing unit 201 and a transmitting unit 202. The processing unit 201 is used to execute the operation of step 101 in the above embodiment, and the transmitting unit 202 is used to execute the operation of step 102 in the above embodiment.

[0482] Figure 15 is a schematic diagram of another structure of the data transmission device in an embodiment of this application. This data transmission device is applied at the receiving end. As shown in Figure 15, the data transmission device includes a receiving unit 302. The receiving unit 302 is used to perform the operation of step 102 in the above embodiment. Optionally, the data transmission device further includes a processing unit 301, which is used to perform the operation of step 103 in the above embodiment.

[0483] It should be understood that the data transmission devices provided in Figures 14 and 15 can also be implemented in other ways. For example, the unit division in the above devices is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system. In addition, the functional units in the various embodiments of this application may be integrated into one processing unit, or they may be independent physical units, or two or more functional units may be integrated into one processing unit. The integrated units described above can be implemented in hardware or as software functional units.

[0484] Figure 16 is a schematic diagram of an optical module structure according to an embodiment of this application. As shown in Figure 16, the optical module includes a processor 401 and an interface 402. The interface 402 can be a transceiver or an input / output interface, and is used to receive signals from other devices and transmit them to the processor 401 or to send signals from the processor 401 to other devices. Optionally, the optical module may also include a memory 403, wherein the memory 403 is used to store program instructions and data.

[0485] In one possible scenario, the optical module is used at the transmitting end, and the processor 401 is used to execute the operation of step 101 in the above embodiments. For example, the processor 401 includes the processing unit 201 shown in FIG. 14. As an example, the processor 401 executes the operation of step 101 in the above embodiments to obtain a first data frame and sends the first data frame through interface 402. In this example, interface 402 may specifically refer to an electrical interface. As another example, the processor 401 executes the operation of step 101 in the above embodiments to obtain a first data frame, and the modulator in the optical module performs signal processing such as electro-optic conversion according to the first data frame to obtain an optical signal, and then sends the optical signal through interface 402. In this example, interface 402 may specifically refer to an optical interface.

[0486] In another possible scenario, the optical module is applied at the receiving end, and the processor 401 is used to execute the operation of step 103 in the above embodiments. For example, the processor 401 includes the processing unit 301 shown in FIG. 15. As an example, the interface receives an optical signal transmitted through the channel, the demodulator in the optical module performs signal processing such as photoelectric conversion on the optical signal to obtain a second data frame, and the processor 401 executes the operation of step 103 in the above embodiments on the second data frame. In this example, the interface 402 may specifically refer to an optical interface. As another example, the demodulator in the optical module performs signal processing such as photoelectric conversion on the received optical signal to obtain a second data frame, and transmits the second data frame to the processor 401 through the interface 402. The processor 401 executes the operation of step 103 in the above embodiments on the second data frame. In this example, the interface 402 may specifically refer to an electrical interface.

[0487] Typically, an optical module consists of optoelectronic devices, a processor, and an interface. The optoelectronic devices include transmitting and receiving devices. The transmitting end of the optical module converts electrical signals into optical signals and transmits them through optical fibers. The receiving end of the optical module receives the optical signals and converts them back into electrical signals.

[0488] It should be noted that the types of optical modules in this application embodiment include, but are not limited to, normal optical modules, near package optics (NPO) modules, and co-packaged optics (CPO) modules. Normal optical modules can perform functions including, but not limited to, digital signal processing (DSP) and clock data recovery (CDR). For example, a normal optical module converts analog signals to digital signals, performs DSP on the digital signals, and then converts them back to analog signals before sending them to the host device. Because DSP requires retiming, a normal optical module can also be called a retimed module. Normal optical modules are connected to the host device via an attachment unit interface (AUI). NPO and CPO modules do not have pluggable physical packaging and are closer to the host device. NPO and CPO modules can also be called optical engines. NPO or CPO technology is a technology that "packages" the host device (or host chip) and the optical engine. When NPO technology is used to encapsulate the host-side device and the optical engine, the optical engine can be called an NPO module. When CPO technology is used to encapsulate the host-side device and the optical engine, the optical engine can be called a CPO module.

[0489] Figure 17 is a schematic diagram of a transmitting device according to an embodiment of this application. As shown in Figure 17, the transmitting device includes a host-side device 501 and an optical module 502. The host-side device 501 is used to send electrical signals to the optical module 502, and the optical module 502 converts the electrical signals into optical signals and transmits the optical signals through the channel. For example, the host-side device 501 may specifically be a switch, router, or server. The transmitting device can be a communication device including the host-side device 501 and the optical module 502. It should also be understood that the transmitting devices in this embodiment are named based on the data flow direction and do not limit the function of the device. For example, the transmitting device may also have a receiving function.

[0490] Figure 18 is a schematic diagram of a receiving device in an embodiment of this application. As shown in Figure 18, the receiving device includes a host-side device 601 and an optical module 602. The optical module 602 is used to convert the received optical signal into an electrical signal and send the electrical signal to the host-side device 601. For example, the host-side device 601 may specifically be a switch, router, or server. The receiving device can be a communication device including the host-side device 601 and the optical module 602. It should also be understood that the receiving device in the embodiments of this application is named based on the data flow direction and does not limit the function of the device. For example, the receiving device may also have a sending function.

[0491] This application also provides an Optical Transport Network (OTN) device, which includes line-side equipment and client-side equipment. The client-side equipment may also be referred to as a tributary-side equipment in some scenarios. The line-side equipment includes a processor and an interface. In one possible scenario, the OTN device is used at the transmitting end, and the processor is used to execute the operation of step 101 in the above embodiment. In another possible scenario, the OTN device is used at the receiving end, and the processor is used to execute the operation of step 103 in the above embodiment. The interface can be a transceiver or an input / output interface, used to receive signals from other devices besides the line-side equipment and transmit them to the processor, or to send signals from the processor to other devices besides the line-side equipment.

[0492] This application also provides a chip. The chip integrates circuitry for implementing the functions of the processor 401 described above and one or more interfaces. As an example, the chip integrates a memory. As another example, when the chip does not integrate a memory, it can be connected to an external memory via an interface. The chip can perform the method steps of any one or more of the foregoing embodiments. Alternatively, the chip can implement the actions performed by the data processing device in the foregoing embodiments based on program code stored in the memory.

[0493] As an example, the chip in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor, any conventional processor, or a processing circuit that implements a specific function.

[0494] This application also provides a computer-readable storage medium including a program or instructions that, when run on a computer, cause the method performed as described in the above method embodiments to be implemented.

[0495] It should be understood that the processor mentioned in the embodiments of this application can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit, integrated circuit, etc. When implemented in software, the processor can be a general-purpose processor that reads software code stored in memory. The memory can exist independently and be connected to the processor, or the memory can be integrated with the processor.

[0496] As an example, the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor, any conventional processor, or a processing circuit that implements a specific function.

[0497] In embodiments of this application, the memory may be random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium may also be a component of the processor. The processor and storage medium may reside in an ASIC. Additionally, the ASIC may reside in a network device or a terminal device. Alternatively, the processor and storage medium may exist as discrete components in the network device or terminal device.

[0498] In the above embodiments, it can be implemented entirely or partially by software, hardware, firmware, or any combination thereof.

[0499] When implemented in hardware, the data processing method provided in this application embodiment may be implemented without reading software code or instructions. For example, it may be implemented by CPU, DSP, ASIC, FPGA, other programmable logic devices, transistor logic devices, hardware components, or any combination thereof.

[0500] When implemented using software, it can be implemented entirely or partially in the form of a computer program product. A computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, all or part of the processes or functions of the embodiments of this application are performed. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a terminal device, or other programmable device. The computer program or instructions can be stored in or transmitted through a computer-readable storage medium. The computer-readable storage medium can be any available medium that a computer can access, or a data storage device such as a server that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a Digital Versatile Disc (DVD); or it can be a semiconductor medium, such as a solid-state disk (SSD).

[0501] Finally, it should be noted that the above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A data transmission method, characterized by, The method comprises: acquiring a data frame, the data frame comprising N symbols in one polarization direction, each of every M consecutive symbols in the N symbols comprising one pilot symbol and M-1 payload symbols, N=MxD, D being an even number, M being an integer greater than 1, at least one of the D pilot symbols taking one of -A1-A1j, -A1+A1j, A1-A1j and A1+A1j, at least one of the D pilot symbols taking one of -A2-A2j, -A2+A2j, A2-A2j and A2+A2j, A1 and A2 being real numbers not equal to 0, A1<A2, j representing an imaginary unit; sending the data frame.

2. The method of claim 1, wherein, The sum of the D pilot symbols is 0.

3. The method according to claim 1 or 2, characterized in that, The D pilot symbols satisfy direct current balance.

4. The method according to any one of claims 1 to 3, characterized in that, The total number of pilot symbols in the D pilot symbols taking -A1-A1j, -A1+A1j, A1-A1j or A1+A1j is D1, the total number of pilot symbols in the D pilot symbols taking -A2-A2j, -A2+A2j, A2-A2j or A2+A2j is D2, D=D1+D2, D1 and D2 are integers greater than 0.

5. The method of claim 4, wherein, The sum of the D1 pilot symbols is 0, the sum of the D2 pilot symbols is 0, D1 and D2 are even numbers.

6. The method according to claim 4 or 5, characterized in that, D1≥D2.

7. The method according to any one of claims 4 to 6, characterized in that, The number of pilot symbols in the D1 pilot symbols taking -A1-A1j, -A1+A1j, A1-A1j and A1+A1j respectively differs by less than or equal to 2, the number of pilot symbols in the D2 pilot symbols taking -A2-A2j, -A2+A2j, A2-A2j and A2+A2j respectively differs by less than or equal to 2.

8. The method according to any one of claims 4 to 7, characterized in that, D=96, D1=D / 2=48, in the D1 pilot symbols, the number of pilot symbols taking -A1-A1j is d1, the number of pilot symbols taking -A1+A1j is d2, the number of pilot symbols taking A1-A1j is d3, the number of pilot symbols taking A1+A1j is d4, d1=d4, d2=d3, D1=d1+d2+d3+d4; d1=11, d2=13, d3=13, d4=11; or, d1=13, d2=11, d3=11, d4=13; or, d1=12, d2=12, d3=12, d4=12.

9. The method according to any one of claims 4 to 7, characterized in that, D=96, D2=D / 2=48, in the D2 pilot symbols, the number of pilot symbols taking -A2-A2j is d5, the number of pilot symbols taking -A2+A2j is d6, the number of pilot symbols taking A2-A2j is d7, the number of pilot symbols taking A2+A2j is d8, d5=d8, d6=d7, D2=d5+d6+d7+d8; d5=11, d6=13, d7=13, d8=11; or, d5=13, d6=11, d7=11, d8=13; or, d5=12, d6=12, d7=12, d8=12.

10. The method according to any one of claims 1 to 9, characterized in that, The data frame includes 2×D pilot symbols in two polarization directions, and the number of pilot symbols with values of -A1-A1j, -A1+A1j, A1-A1j, A1+A1j, -A2-A2j, -A2+A2j, A2-A2j and A2+A2j is D / 4 respectively.

11. The method according to any one of claims 1 to 10, characterized in that, The D pilot symbols included in the data frame in the first polarization direction are different from the D pilot symbols included in the data frame in the second polarization direction.

12. The method according to any one of claims 1 to 11, characterized in that, The data frame adopts a symbol mapping mode of dual-polarization 16-quadrature amplitude modulation (DP-16QAM), and A1 / A2=1 / 3. Alternatively, The data frame adopts a symbol mapping mode of dual-polarization 64-quadrature amplitude modulation (DP-64QAM), and A1 / A2=1 / 3, or A1 / A2=1 / 5, or A1 / A2=1 / 7, or A1 / A2=3 / 5, or A1 / A2=3 / 7, or A1 / A2=5 / 7.

13. The method according to any one of claims 1 to 12, characterized in that, In one polarization direction, the D pilot symbols are generated by a target polynomial and a seed.

14. The method of claim 13, wherein, The order of the target polynomial is less than or equal to 11, and the number of terms of the target polynomial is greater than or equal to 2 and less than or equal to 8.

15. The method according to claim 13 or 14, characterized in that, The target polynomial is one of: x 10 +a9x 9 +a8x 8 +a7x 7 +a6x 6 +a5x 5 +a4x 4 +a3x 3 +a2x 2 +a1x+1; x 9 +a8x 8 +a7x 7 +a6x 6 +a5x 5 +a4x 4 +a3x 3 +a2x 2 +a1x+1; x 8 +a7x 7 +a6x 6 +a5x 5 +a4x 4 +a3x 3 +a2x 2 +a1x+1; x 11 +a 10 x 10 +a9x 9 +a8x 8 +a7x 7 +a6x 6 +a5x 5 +a4x 4 +a3x 3 +a2x 2 + a1x+1.

16. The method according to any one of claims 13 to 15, characterized in that, In one polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed, and every 3 consecutive bits in the first bit sequence correspond to one pilot symbol.

17. The method according to any one of claims 13 to 15, characterized in that, In one polarization direction, a first bit sequence including 3×D bits is generated by the target polynomial and the seed, and every 3 consecutive bits in the first bit sequence correspond to 4 bits, and the 4 bits are subjected to symbol mapping to obtain one pilot symbol.

18. The method of any one of claims 13-15, wherein, In the first polarization direction, the D pilot symbols are generated by the target polynomial, a first seed and a second seed, and in the second polarization direction, the D pilot symbols are generated by the target polynomial, a third seed and a fourth seed.

19. The method of claim 18, wherein, In the first polarization direction, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, and a third bit sequence including D bits is generated by the target polynomial and the second seed, and 3 bits including every 2 consecutive bits in the second bit sequence and 1 bit in the third bit sequence correspond to one pilot symbol. In the second polarization direction, a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed, and a fifth bit sequence including D bits is generated by the target polynomial and the fourth seed, and 3 bits including every 2 consecutive bits in the fourth bit sequence and 1 bit in the fifth bit sequence correspond to one pilot symbol.

20. The method of claim 18, wherein, In the first polarization direction, a second bit sequence including 2×D bits is generated by the target polynomial and the first seed, and a third bit sequence including D bits is generated by the target polynomial and the second seed, and 4 first bits including every 2 consecutive bits in the second bit sequence and 1 bit in the third bit sequence are subjected to symbol mapping to obtain one pilot symbol. In the second polarization direction, a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed, a fifth bit sequence including D bits is generated by the target polynomial and the fourth seed, 3 bits including every 2 bits in the fourth bit sequence and 1 bit in the fifth bit sequence correspond to 4 second bits, and the 4 second bits are subjected to symbol mapping to obtain a pilot symbol.

21. The method of any one of claims 13-15, wherein, D pilot symbols in the first polarization direction are generated by the target polynomial, a first seed and a second seed, and D pilot symbols in the second polarization direction are generated by the target polynomial, the second seed and a third seed.

22. The method of claim 21, wherein, A second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed; In the first polarization direction, 3 bits including every 2 bits in the second bit sequence and 1 bit in the third bit sequence correspond to one pilot symbol, and in the second polarization direction, 3 bits including every 2 bits in the fourth bit sequence and 1 bit in the third bit sequence correspond to one pilot symbol.

23. The method of claim 21, wherein, A second bit sequence including 2×D bits is generated by the target polynomial and the first seed, a third bit sequence including 2×D bits is generated by the target polynomial and the second seed, and a fourth bit sequence including 2×D bits is generated by the target polynomial and the third seed; In the first polarization direction, 3 bits including every 2 bits in the second bit sequence and 1 bit in the third bit sequence correspond to 4 first bits, the 4 first bits are subjected to symbol mapping to obtain one pilot symbol, and in the second polarization direction, 3 bits including every 2 bits in the fourth bit sequence and 1 bit in the third bit sequence correspond to 4 second bits, the 4 second bits are subjected to symbol mapping to obtain one pilot symbol.

24. The method of any one of claims 1 to 23, wherein, D = 96, 96 pilot symbols of the data frame in the first polarization direction and 96 pilot symbols in the second polarization direction satisfy the relationship shown in the following table, wherein pi is 1 or 3, qi is 1 or 3, and 1≤i≤96; Table 4 25. The method of any one of claims 1 to 24, wherein, N = 6144, M = 64.

26. The method of any one of claims 1 to 25, wherein, Each pilot symbol is located at the starting position in the consecutive M symbols.

27. A method of data transmission, characterized by Comprise: Receiving a second data frame transmitted by a first data frame through a channel, the first data frame including N symbols in a polarization direction, each continuous M symbols in the N symbols including one pilot symbol and M-1 payload symbols, N=MxD, D being an even number, M being an integer greater than 1, at least one pilot symbol in the D pilot symbols taking one of -A1-A1j, -A1+A1j, A1-A1j and A1+A1j, at least one pilot symbol in the D pilot symbols taking one of -A2-A2j, -A2+A2j, A2-A2j and A2+A2j, A1 and A2 being real numbers not equal to 0, A1 28. A data transmission apparatus, comprising: Comprising: A processing unit and a sending unit; The processing unit is configured to: acquire a data frame, the data frame including N symbols in a polarization direction, each continuous M symbols in the N symbols including one pilot symbol and M-1 payload symbols, N=MxD, D being an even number, M being an integer greater than 1, at least one pilot symbol in the D pilot symbols taking one of -A1-A1j, -A1+A1j, A1-A1j and A1+A1j, at least one pilot symbol in the D pilot symbols taking one of -A2-A2j, -A2+A2j, A2-A2j and A2+A2j, A1 and A2 being real numbers not equal to 0, A1 The sending unit is configured to: send the data frame.

29. A data transmission apparatus, comprising: Comprising: A receiving unit; The receiving unit is configured to: receive a second data frame transmitted by a first data frame through a channel, the first data frame including N symbols in a polarization direction, each continuous M symbols in the N symbols including one pilot symbol and M-1 payload symbols, N=MxD, D being an even number, M being an integer greater than 1, at least one pilot symbol in the D pilot symbols taking one of -A1-A1j, -A1+A1j, A1-A1j and A1+A1j, at least one pilot symbol in the D pilot symbols taking one of -A2-A2j, -A2+A2j, A2-A2j and A2+A2j, A1 and A2 being real numbers not equal to 0, A1 30. A chip, characterized by The chip is configured to perform the method of any one of claims 1-27.

31. An optical module characterized by comprising: The optical module comprises a processor and an interface, the interface is configured to transceive signals, and the processor is configured to perform the method of any one of claims 1-26.

32. A transmitting device, comprising: The sending device comprises a host-side device and the optical module of claim 31, and the optical module is configured to convert an electrical signal from the host-side device into an optical signal and send the optical signal.

33. An optical module characterized by comprising: The optical module comprises a processor and an interface, the interface is configured to transceive signals, and the processor is configured to perform the method of claim 27.

34. A receiving device, comprising: The receiving device comprises a host-side device and the optical module as claimed in claim 33, which is used to convert the received optical signal into an electrical signal and send the electrical signal to the host-side device.

35. A communication system, characterized by Comprising: The transmitting device as claimed in claim 32 and the receiving device as claimed in claim 34, which are used to transmit signals to each other.

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