Data transmission method and apparatus, and system

Abstract

Disclosed in the embodiments of the present application are a data transmission method and apparatus, and a system, which have small transmission redundancy and in which an added preset symbol sequence has good correlation, thereby helping to improve the quality of a signal recovered at a receiving end and being well applicable to various coherent transmission scenarios. The data frame sent by a sending end comprises a plurality of subframes, wherein the subframes comprise training symbols and pilot symbols. In a polarization direction, each subframe among the plurality of subframes comprises an even number of training symbols, and each consecutive NPG symbols in each subframe among the plurality of subframes comprise one pilot symbol, wherein NPG is an integer greater than 1, the value of each training symbol and each pilot symbol is one of -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number, and j represents an imaginary unit, one symbol in each subframe among the plurality of subframes is both a training symbol and a pilot symbol, and the number of pilot symbols in each subframe among the plurality of subframes is 113.

Description

Data transmission method, device and system

[0001] The present application claims priority to the Chinese patent application No. 202411289098.7, filed on September 13, 2024, and entitled "Data transmission method, device and system", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of communication technology, and in particular to a data transmission method, device and system. BACKGROUND

[0003] With the continuous promotion of 5G, cloud computing, big data, artificial intelligence, etc., high-speed optical transmission networks are developing towards large capacity, packetization and intelligentization. Coherent optical communication systems use the amplitude, phase, polarization or frequency of light waves to carry information. In order to combat optical signal distortion caused by dispersion, polarization-related damage, noise, nonlinear effects and other factors during transmission and maintain long-distance transmission, coherent optical communication systems usually add some pre-designed preset symbol sequences in the transmission symbol sequence to facilitate the recovery of the sending symbol at the receiving end.

[0004] The existing transmission symbol sequence is mainly applied to 400 gigabits per second (Gbps) or 800 Gbps scenarios, and cannot adapt to future scenarios of 800 Gbps or more, such as 1.2 terabit per second (Tbps) or 1.6 Tbps, and the transmission redundancy is large. SUMMARY

[0005] The embodiments of the present application provide a data transmission method, device and system, which has smaller transmission redundancy and better correlation of added preset symbol sequences, is beneficial to improve the quality of signal recovered at the receiving end, and can be well applied to various coherent transmission scenarios.

[0006] In a first aspect, the embodiments of the present application provide a data transmission method, which is applied to a sending end. Specifically, the sending end sends a data frame including a plurality of subframes. It should be understood that the data frame includes symbols in two polarization directions, and the structure of the data frame in the two polarization directions is similar. Hereinafter, the structure of the data frame is introduced by taking one of the polarization directions as an example. In one polarization direction, each subframe in the plurality of subframes includes an even number of training symbols, and each continuous N PG symbols in each subframe in the plurality of subframes includes one pilot symbol, and N PGis an integer greater than 1, each of the training symbols and each of the pilot symbols has one of the values -A-Aj, -A+Aj, A-Aj and A+Aj, A is a real number, j represents an imaginary unit, each of the plurality of subframes has one symbol that is both a training symbol and a pilot symbol, and each of the plurality of subframes has a quantity of pilot symbols of 113.

[0007] It should be noted that the method can also be applied to a specific module in the sending end, for example, a signal processor of the sending end. The module can acquire the data frame before sending the data frame. It should be understood that the acquisition of the data frame by the module can be understood as the generation of the data frame by the module itself, or can be understood as the reception of the data frame sent by the module from the previous module. It should also be understood that the sending of the data frame by the module can be understood as the sending of the data frame by the module to the receiving end through the channel, or can be understood as the sending of the data frame by the module to the subsequent module.

[0008] In the embodiment, in one polarization direction, the quantity of pilot symbols in each of the plurality of subframes is 113, and the quantity of training symbols is an even number. Considering that the sequence of training symbols and the sequence of pilot symbols in the subframe share one symbol, one shared symbol needs to be subtracted when the total quantity of symbols of the combination of all training symbols and all pilot symbols in the subframe is calculated. Therefore, the total quantity of symbols of the combination of all training symbols and all pilot symbols in each of the plurality of subframes is an even number, so as to facilitate the design to make the pilot symbols and the training symbols in each of the plurality of subframes satisfy direct current balance, and improve the quality of the recovered signal at the receiving end.

[0009] In some possible embodiments, in one polarization direction, the quantity of training symbols in each of the plurality of subframes is 8, 10 or 12. It should be understood that the more the quantity of training symbols in the subframe, the less the quantity of reserved symbols in the subframe. Therefore, the quantity of training symbols in the subframe is reasonably designed to be 8, 10 or 12, which not only ensures that the function of link training can be realized through sufficient training symbols, but also makes more reserved symbols in the subframe, which is beneficial to future use and innovation.

[0010] In some possible embodiments, the 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generating polynomial and a seed, the generating polynomial is x 10 +x 7 +x 3+1. The seed is 0x34E in the first polarization direction and 0x084 in the second polarization direction, wherein the first polarization direction and the second polarization direction are orthogonal to each other. The generation polynomial and the seed provided herein make the complexity of the pilot symbol generation structure lower, the power consumption smaller, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols better, so as to improve the signal recovery quality at the receiving end. In addition, the generation polynomial and the seed provided herein are conducive to compatibility with the 800ZR scenario.

[0011] In some possible implementation manners, specific values of the respective 113 pilot symbols in each of the plurality of subframes in each of the two polarization directions are provided, which is conducive to achieving direct current balance and better autocorrelation and cross-correlation characteristics of the 113 pilot symbols, thereby improving the signal recovery quality at the receiving end.

[0012] In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, A-Aj, A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj.

[0013] In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, A-Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A-Aj.

[0014] In some possible embodiments, in the first polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj. In the second polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is -2A. It should be understood that, based on the generating polynomials and the seeds for generating the 113 pilot symbols and the values of the 113 pilot symbols provided above, if the constraints provided herein regarding the values of the training symbols are further satisfied, the combination of all the pilot symbols and all the training symbols in each subframe can satisfy the direct current balance, thereby improving the quality of the recovered signal at the receiving end.

[0015] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 8, and the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following tables. It should be understood that in one polarization direction, there are 4 possibilities of values of 8 training symbols 8 , and in combination of 2 polarization directions, there are 2 32 possibilities in total, here providing the possibilities of values of 8 training symbols with better autocorrelation and cross-correlation characteristics in each polarization direction.

[0016] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 10, and the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following tables. It should be understood that in one polarization direction, there are 4 possibilities of values of 10 training symbols 10 , and in combination of 2 polarization directions, there are 2 40 possibilities in total, here providing the possibilities of values of 10 training symbols with better autocorrelation and cross-correlation characteristics in each polarization direction.

[0017] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 12, and the values of the 12 training symbols in the first polarization direction and the values of the 12 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following tables. It should be understood that in one polarization direction, there are 4 possibilities of values of 12 training symbols 12 , and in combination of 2 polarization directions, there are 2 48 possibilities in total, here providing the possibilities of values of 12 training symbols with better autocorrelation and cross-correlation characteristics in each polarization direction.

[0018] In some possible implementation manners, in one polarization direction, the 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generating polynomial and a seed, the generating polynomial is x 10 +x 8 +x 4 +x 3 +1; the seed is 0x19E in the first polarization direction and 0x0D0 in the second polarization direction. The first polarization direction and the second polarization direction are orthogonal to each other. The generating polynomial and the seed provided herein make the complexity of the pilot symbol generation structure lower, the power consumption smaller, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols better, so as to improve the signal recovery quality at the receiving end. In addition, the generating polynomial and the seed provided herein are conducive to compatibility with the 400ZR scenario.

[0019] In some possible implementation manners, specific values of the 113 pilot symbols in each of the plurality of subframes in the two polarization directions are provided, which is conducive to direct current balance, the autocorrelation and cross-correlation characteristics of the 113 pilot symbols are better, and thus the signal recovery quality at the receiving end is improved.

[0020] In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A-Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, -A+Aj, A+Aj, A-Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj.

[0021] In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj.

[0022] In some possible embodiments, in the first polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj. In the second polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A-2Aj. It should be understood that, based on the generation polynomials and the seeds for generating the 113 pilot symbols and the values of the 113 pilot symbols provided above, if the constraints provided herein regarding the values of the training symbols are further satisfied, the combination of all the pilot symbols and all the training symbols in each subframe can satisfy the direct current balance, thereby improving the quality of the recovered signal at the receiving end.

[0023] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 8, the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following table. It should be understood that in one polarization direction, the value of the 8 training symbols has 4 possibilities 8 , the 2 polarization directions together have 2 32 possibilities, here the value of the 8 training symbols in each polarization direction has good autocorrelation and cross-correlation characteristics.

[0024] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 10, the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following table. It should be understood that in one polarization direction, the value of the 10 training symbols has 4 possibilities 10 , the 2 polarization directions together have 2 40 possibilities, here the value of the 10 training symbols in each polarization direction has good autocorrelation and cross-correlation characteristics.

[0025] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 12, the values of the 12 training symbols in the first polarization direction and the values of the 12 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following table. It should be understood that in one polarization direction, the value of the 12 training symbols has 4 possibilities 12 , the 2 polarization directions together have 2 48 possibilities, here the value of the 12 training symbols in each polarization direction has good autocorrelation and cross-correlation characteristics.

[0026] In some possible implementation, N PG = 128, the interval of inserting pilot symbols in the subframe is increased, which is equivalent to reducing the number of added symbols in the data frame, and the transmission redundancy is smaller.

[0027] In some possible implementation manners, the data frame adopts a symbol mapping manner of Quadrature Phase Shift Keying (QPSK), and A=-1 or 1; or the data frame adopts a symbol mapping manner of 16-ary Quadrature Amplitude Modulation (16QAM), and A=-3 or 3.

[0028] In some possible implementation manners, in one polarization direction, each of the subframes includes N TS training symbols, and a total of 113+N TS -1 symbols in each of the subframes satisfy a direct current balance, which is beneficial to improving the quality of recovered signals at the receiving end.

[0029] In some possible implementation manners, in one polarization direction, each of the subframes includes N TS training symbols, and a total of 113+N TS -1 symbols in each of the subframes satisfy a direct current balance, which is beneficial to improving the quality of recovered signals at the receiving end.

[0030] In some possible implementation manners, the subframe arranged at the first position in the data frame is a first type of subframe, the first type of subframe further includes a frame synchronization symbol, a reserved symbol and a pre-formation symbol, in the first type of subframe, the training symbol is located before the frame synchronization symbol, the frame synchronization symbol is located before the reserved symbol, and the reserved symbol is located before the pre-formation symbol. The data frame includes at least one second type of subframe, the second type of subframe further includes a pre-formation symbol, and in the second type of subframe, the training symbol is located before the pre-formation symbol.

[0031] In a second aspect, an embodiment of the present application provides a data transmission method, which is applied to a receiving end. Specifically, the receiving end receives a second data frame transmitted by a first data frame 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, and 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, the first data frame includes a plurality of subframes. In one polarization direction, each of the plurality of subframes includes an even number of training symbols, each of the plurality of subframes includes one pilot symbol for every N PG training symbols, N PG is an integer greater than 1, each training symbol and each pilot symbol takes one of -A-Aj, -A+Aj, A-Aj and A+Aj, A is a real number, j represents an imaginary unit, each of the plurality of subframes has one symbol that is both a training symbol and a pilot symbol, and the number of pilot symbols in each of the plurality of subframes is 113.

[0032] In some possible implementation manners, after receiving the second data frame, the receiving end performs signal processing on the second data frame.

[0033] In some possible implementation manners, in one polarization direction, the number of training symbols in each of the plurality of subframes is 8, 10, or 12. It should be understood that the more the number of training symbols in a subframe, the less the number of reserved symbols in the corresponding subframe. Therefore, the number of training symbols in a subframe is reasonably designed to be 8, 10, or 12 here, which not only ensures that the function of link training can be realized through sufficient training symbols, but also enables more reserved symbols in the subframe, which is conducive to future use and innovation.

[0034] In some possible implementation manners, the 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generating polynomial and a seed, the generating polynomial is x 10 +x 7 +x 3 +x+1. The seed is 0x34E in the first polarization direction and 0x084 in the second polarization direction, where the first polarization direction and the second polarization direction are orthogonal to each other. The generating polynomial and the seed provided here make the complexity of the pilot symbol generation structure lower, the power consumption smaller, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols better, so as to improve the quality of the signal recovered by the receiving end. In addition, the generating polynomial and the seed provided here are conducive to compatibility with the 800ZR scenario.

[0035] In some possible implementation manners, specific values of the 113 pilot symbols in each of the plurality of subframes in the two polarization directions are provided, which is conducive to realizing direct current balance, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols are better, thereby improving the quality of the signal recovered by the receiving end.

[0036] In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, A-Aj, A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj.

[0037] In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, A-Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A-Aj.

[0038] In some possible implementations, in the first polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj. In the second polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is -2A. It should be understood that, based on the generation polynomials and the seeds for generating the 113 pilot symbols and the values of the 113 pilot symbols provided above, if the constraints provided herein regarding the values of the training symbols are further satisfied, the combination of all the pilot symbols and all the training symbols in each subframe can satisfy the direct current balance, thereby improving the quality of the recovered signal at the receiving end.

[0039] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 8, and the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 3, where the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 8 training symbols 8 , and 2 polarization directions together have 2 32 possibilities, and here the possibilities of values of 8 training symbols are provided, which have better autocorrelation and cross-correlation characteristics in each polarization direction.

[0040] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 10, and the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 4, where the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 10 training symbols 10 , and 2 polarization directions together have 2 40 possibilities, and here the possibilities of values of 10 training symbols are provided, which have better autocorrelation and cross-correlation characteristics in each polarization direction.

[0041] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 12, and the values of the 12 training symbols in the first polarization direction and the values of the 12 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 5, where the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 12 training symbols 12 , and 2 polarization directions together have 2 48 possibilities, and here the possibilities of values of 12 training symbols are provided, which have better autocorrelation and cross-correlation characteristics in each polarization direction.

[0042] In some possible implementations, in one polarization direction, the 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generating polynomial and a seed, the generating polynomial is x 10 +x 8 +x 4 +x 3+1; the seed is 0x19E in the first polarization direction and the seed is 0x0D0 in the second polarization direction. The first polarization direction and the second polarization direction are orthogonal to each other. The generation polynomial and the seed provided herein make the complexity of the pilot symbol generation structure lower, the power consumption smaller, and make the autocorrelation and cross-correlation characteristics of the 113 pilot symbols better, so as to improve the signal recovery quality at the receiving end. In addition, the generation polynomial and the seed provided herein are conducive to compatibility with the 400ZR scenario.

[0043] In some possible implementation manners, specific values of the respective 113 pilot symbols in each of the plurality of subframes in each of the two polarization directions are provided, which is conducive to realizing direct current balance, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols are better, thereby improving the signal recovery quality at the receiving end.

[0044] In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A-Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, -A+Aj, A+Aj, A-Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj.

[0045] In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj.

[0046] In some possible embodiments, in the first polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj. In the second polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A-2Aj. It should be understood that, based on the generation polynomials and the seeds for generating the 113 pilot symbols and the values of the 113 pilot symbols provided above, if the constraints provided herein regarding the values of the training symbols are further satisfied, the combination of all the pilot symbols and all the training symbols in each subframe can satisfy the direct current balance, thereby improving the quality of the recovered signal at the receiving end.

[0047] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 8, the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 7, wherein the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 8 training symbols 8 , and in combination of the two polarization directions, there are 2 32 possibilities, and here the possibilities of values of 8 training symbols are provided, in which the autocorrelation and cross-correlation characteristics in each polarization direction are better.

[0048] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 10, the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 8, wherein the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 10 training symbols 10 , and in combination of the two polarization directions, there are 2 40 possibilities, and here the possibilities of values of 10 training symbols are provided, in which the autocorrelation and cross-correlation characteristics in each polarization direction are better.

[0049] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 12, the values of the 12 training symbols in the first polarization direction and the values of the 12 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 9, wherein the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 12 training symbols 12 , and in combination of the two polarization directions, there are 2 48 possibilities, and here the possibilities of values of 12 training symbols are provided, in which the autocorrelation and cross-correlation characteristics in each polarization direction are better.

[0050] In some possible implementation, N PG = 128, the interval of inserting pilot symbols in the subframe is increased, which is equivalent to reducing the number of added symbols in the data frame, and the transmission redundancy is smaller.

[0051] In some possible implementation manners, the data frame adopts a symbol mapping manner of Quadrature Phase Shift Keying (QPSK), and A=-1 or 1; or the data frame adopts a symbol mapping manner of 16-ary Quadrature Amplitude Modulation (16QAM), and A=-3 or 3.

[0052] In some possible implementation manners, in one polarization direction, each of the subframes includes N TS training symbols, and a total of 113+N TS -1 symbols in the subframe satisfy that a sum of the symbols is 0, which is beneficial to improving signal recovery quality at a receiving end.

[0053] In some possible implementation manners, in one polarization direction, each of the subframes includes N TS training symbols, and a total of 113+N TS -1 symbols in the subframe satisfy direct current balance, which is beneficial to improving signal recovery quality at a receiving end.

[0054] In some possible implementation manners, a subframe arranged at a first position in the data frame is a first type of subframe, the first type of subframe further includes a frame synchronization symbol, a reserved symbol and a pre-formation symbol, in the first type of subframe, the training symbol is located before the frame synchronization symbol, the frame synchronization symbol is located before the reserved symbol, and the reserved symbol is located before the pre-formation symbol. The data frame includes at least one second type of subframe, the second type of subframe further includes the pre-formation symbol, and in the second type of subframe, the training symbol is located before the pre-formation symbol.

[0055] In a third aspect, an embodiment of the present application provides a data transmission apparatus, including a processing unit and a sending unit. The processing unit is configured to: acquire a data frame including a plurality of subframes. In one polarization direction, each of the plurality of subframes includes an even number of training symbols, and each of the plurality of subframes includes, in each continuous N PG training symbols, one pilot symbol, N PG is an integer greater than 1, each of the training symbols and each of the pilot symbols has a value of one of -A-Aj, -A+Aj, A-Aj and A+Aj, A is a real number, j represents an imaginary unit, each of the plurality of subframes has one symbol that is both a training symbol and a pilot symbol, and each of the plurality of subframes has a total of 113 pilot symbols. The sending unit is configured to: send the data frame.

[0056] In some possible implementation manners, the number of training symbols in each of the plurality of subframes is 8, 10 or 12 in one polarization direction. It should be understood that the more the number of training symbols in a subframe, the less the number of reserved symbols in the corresponding subframe. Therefore, the number of training symbols in a subframe is reasonably designed to be 8, 10 or 12 herein, which not only ensures that the function of link training can be implemented through sufficient training symbols, but also enables more reserved symbols in the subframe, which is beneficial to future use and innovation.

[0057] In some possible implementation manners, the 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generating polynomial and a seed, the generating polynomial is x 10 +x 7 +x 3 +x+1. The seed is 0x34E in the first polarization direction and is 0x084 in the second polarization direction, where the first polarization direction and the second polarization direction are orthogonal to each other. The generating polynomial and the seed provided herein make the complexity of the pilot symbol generation structure lower and the power consumption smaller, and make the autocorrelation and cross-correlation characteristics of the 113 pilot symbols better, so as to improve the quality of the signal recovered at the receiving end. In addition, the generating polynomial and the seed provided herein are beneficial to compatibility with the 800ZR scenario.

[0058] In some possible implementation manners, specific values of the 113 pilot symbols in each of the plurality of subframes in the two polarization directions are provided, which is beneficial to direct current balance, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols are better, thereby improving the quality of the signal recovered at the receiving end.

[0059] In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, A-Aj, A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj.

[0060] In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, A-Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A-Aj.

[0061] In some possible embodiments, in the first polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj. In the second polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is -2A. It should be understood that, based on the generation polynomials and the seeds for generating the 113 pilot symbols and the values of the 113 pilot symbols provided above, if the constraints provided herein regarding the values of the training symbols are further satisfied, the combination of all the pilot symbols and all the training symbols in each subframe can satisfy the direct current balance, thereby improving the quality of the recovered signal at the receiving end.

[0062] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 8, and the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 3, where the first polarization direction can also be referred to as the X polarization direction, and the second polarization direction can also be referred to as the Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities for the values of the 8 training symbols 8 , and in combination of the 2 polarization directions, there are 2 32 possibilities, and here the 8 training symbols are provided with better autocorrelation and cross-correlation characteristics in each polarization direction.

[0063] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 10, and the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 4, where the first polarization direction can also be referred to as the X polarization direction, and the second polarization direction can also be referred to as the Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities for the values of the 10 training symbols 10 , and in combination of the 2 polarization directions, there are 2 40 possibilities, and here the 10 training symbols are provided with better autocorrelation and cross-correlation characteristics in each polarization direction.

[0064] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 12, and the values of the 12 training symbols in the first polarization direction and the values of the 12 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 5, where the first polarization direction can also be referred to as the X polarization direction, and the second polarization direction can also be referred to as the Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities for the values of the 12 training symbols 12 , and in combination of the 2 polarization directions, there are 2 48 possibilities, and here the 12 training symbols are provided with better autocorrelation and cross-correlation characteristics in each polarization direction.

[0065] In some possible implementations, in one polarization direction, the 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generating polynomial and a seed, the generating polynomial is x 10 +x 8 +x 4 +x 3+1; the seed is 0x19E in the first polarization direction and 0x0D0 in the second polarization direction. The first polarization direction and the second polarization direction are orthogonal to each other. The generation polynomial and the seed provided herein make the complexity of the pilot symbol generation structure lower, the power consumption smaller, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols better, so as to improve the signal recovery quality at the receiving end. In addition, the generation polynomial and the seed provided herein are conducive to compatibility with the 400ZR scenario.

[0066] In some possible implementation manners, specific values of the respective 113 pilot symbols in each of the plurality of subframes in each of the two polarization directions are provided, which is conducive to achieving direct current balance and better autocorrelation and cross-correlation characteristics of the 113 pilot symbols, thereby improving the signal recovery quality at the receiving end.

[0067] In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A-Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, -A+Aj, A+Aj, A-Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj.

[0068] In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj.

[0069] In some possible embodiments, in the first polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj. In the second polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A-2Aj. It should be understood that, based on the generation polynomials and the seeds for generating the 113 pilot symbols and the values of the 113 pilot symbols provided above, if the constraints provided herein regarding the values of the training symbols are further satisfied, the combination of all the pilot symbols and all the training symbols in each subframe can satisfy the direct current balance, thereby improving the quality of the recovered signal at the receiving end.

[0070] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 8, the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 7, wherein the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 8 training symbols 8 , and in combination of 2 polarization directions, there are 2 32 possibilities, and here the possibilities of values of 8 training symbols are provided, in which the autocorrelation and cross-correlation characteristics are both good in each polarization direction.

[0071] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 10, the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 8, wherein the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 10 training symbols 10 , and in combination of 2 polarization directions, there are 2 40 possibilities, and here the possibilities of values of 10 training symbols are provided, in which the autocorrelation and cross-correlation characteristics are both good in each polarization direction.

[0072] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 12, the values of the 12 training symbols in the first polarization direction and the values of the 12 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 9, wherein the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 12 training symbols 12 , and in combination of 2 polarization directions, there are 2 48 possibilities, and here the possibilities of values of 12 training symbols are provided, in which the autocorrelation and cross-correlation characteristics are both good in each polarization direction.

[0073] In some possible implementation, N PG = 128, the interval of inserting pilot symbols in the subframe is increased, which is equivalent to reducing the number of added symbols in the data frame, and the transmission redundancy is smaller.

[0074] In some possible implementation manners, the data frame adopts a symbol mapping manner of Quadrature Phase Shift Keying (QPSK), and A=-1 or 1; or the data frame adopts a symbol mapping manner of 16-ary Quadrature Amplitude Modulation (16QAM), and A=-3 or 3.

[0075] In some possible implementation manners, in one polarization direction, each of the subframes includes N TS training symbols, and a total of 113+N TS -1 symbols in each of the subframes satisfy a direct current balance, which is beneficial to improving the quality of signal recovery at the receiving end.

[0076] In some possible implementation manners, in one polarization direction, each of the subframes includes N TS training symbols, and a total of 113+N TS -1 symbols in each of the subframes satisfy a direct current balance, which is beneficial to improving the quality of signal recovery at the receiving end.

[0077] In some possible implementation manners, the subframe arranged at the first position in the data frame is a first type of subframe, the first type of subframe further includes a frame synchronization symbol, a reserved symbol and a pre-formation symbol, in the first type of subframe, the training symbol is located before the frame synchronization symbol, the frame synchronization symbol is located before the reserved symbol, and the reserved symbol is located before the pre-formation symbol. The data frame includes at least one second type of subframe, the second type of subframe further includes a pre-formation symbol, and in the second type of subframe, the training symbol is located before the pre-formation symbol.

[0078] In a fourth aspect, an embodiment of the present application provides a data transmission apparatus, including 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 includes a plurality of subframes, in one polarization direction, each of the plurality of subframes includes an even number of training symbols, each of the plurality of subframes includes a pilot symbol every N PG training symbols, N PG is an integer greater than 1, each of the training symbols and each of the pilot symbols has a value of one of -A-Aj, -A+Aj, A-Aj and A+Aj, A is a real number, j represents an imaginary unit, each of the plurality of subframes has one symbol that is both a training symbol and a pilot symbol, and each of the plurality of subframes has a total of 113 pilot symbols.

[0079] In some possible implementation manners, the data transmission apparatus further includes a processing unit, and the processing unit is configured to perform signal processing on the second data frame.

[0080] In some possible implementation manners, the number of training symbols in each of the plurality of subframes is 8, 10 or 12 in one polarization direction. It should be understood that the more the number of training symbols in a subframe, the less the number of reserved symbols in the corresponding subframe. Therefore, the number of training symbols in a subframe is reasonably designed as 8, 10 or 12 here, which not only ensures that the function of link training can be realized through enough training symbols, but also makes it possible to reserve more reserved symbols in the subframe, which is conducive to future use and innovation.

[0081] In some possible implementation manners, the 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generating polynomial and a seed, the generating polynomial is x 10 +x 7 +x 3 +x+1. The seed is 0x34E in the first polarization direction, and the seed is 0x084 in the second polarization direction, where the first polarization direction and the second polarization direction are orthogonal to each other. The generating polynomial and the seed provided here make the complexity of the pilot symbol generation structure lower, the power consumption smaller, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols better, so as to improve the quality of the signal recovered at the receiving end. In addition, the generating polynomial and the seed provided here are conducive to compatibility with the 800ZR scenario.

[0082] In some possible implementation manners, specific values of the 113 pilot symbols in each of the plurality of subframes in the two polarization directions are provided, which is conducive to realizing direct current balance, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols are better, thereby improving the quality of the signal recovered at the receiving end.

[0083] In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, A-Aj, A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj.

[0084] In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, A-Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A-Aj.

[0085] In some possible implementations, in the first polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj. In the second polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is -2A. It should be understood that, based on the generation polynomials and the seeds for generating the 113 pilot symbols and the values of the 113 pilot symbols provided above, if the constraints provided herein regarding the values of the training symbols are further satisfied, the combination of all the pilot symbols and all the training symbols in each subframe can satisfy the direct current balance, thereby improving the quality of the recovered signal at the receiving end.

[0086] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 8, and the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 3, where the first polarization direction can also be referred to as the X polarization direction, and the second polarization direction can also be referred to as the Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities for the values of the 8 training symbols 8 , and in combination of the 2 polarization directions, there are 2 32 possibilities, where the 8 training symbols are provided with better autocorrelation and cross-correlation characteristics in each polarization direction.

[0087] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 10, and the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 4, where the first polarization direction can also be referred to as the X polarization direction, and the second polarization direction can also be referred to as the Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities for the values of the 10 training symbols 10 , and in combination of the 2 polarization directions, there are 2 40 possibilities, where the 10 training symbols are provided with better autocorrelation and cross-correlation characteristics in each polarization direction.

[0088] In some possible implementations, in one polarization direction, the number of training symbols in each of the plurality of subframes is 12, and the values of the 12 training symbols in the first polarization direction and the values of the 12 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 5, where the first polarization direction can also be referred to as the X polarization direction, and the second polarization direction can also be referred to as the Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities for the values of the 12 training symbols 12 , and in combination of the 2 polarization directions, there are 2 48 possibilities, where the 12 training symbols are provided with better autocorrelation and cross-correlation characteristics in each polarization direction.

[0089] In some possible implementations, in one polarization direction, the 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generating polynomial and a seed, the generating polynomial is x 10 +x 8 +x 4 +x 3+1; the seed is 0x19E in the first polarization direction and 0x0D0 in the second polarization direction. The first polarization direction and the second polarization direction are orthogonal to each other. The generation polynomial and the seed provided herein make the complexity of the pilot symbol generation structure lower, the power consumption smaller, and the autocorrelation and cross-correlation characteristics of the 113 pilot symbols better, so as to improve the signal recovery quality at the receiving end. In addition, the generation polynomial and the seed provided herein are conducive to compatibility with the 400ZR scenario.

[0090] In some possible implementation manners, specific values of the respective 113 pilot symbols in each of the plurality of subframes in each of the two polarization directions are provided, which is conducive to achieving direct current balance and better autocorrelation and cross-correlation characteristics of the 113 pilot symbols, thereby improving the signal recovery quality at the receiving end.

[0091] In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A-Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, -A+Aj, A+Aj, A-Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj.

[0092] In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj.

[0093] In some possible embodiments, in the first polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj. In the second polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A-2Aj. It should be understood that, based on the generation polynomials and the seeds for generating the 113 pilot symbols and the values of the 113 pilot symbols provided above, if the constraints provided herein regarding the values of the training symbols are further satisfied, the combination of all the pilot symbols and all the training symbols in each subframe can satisfy the direct current balance, thereby improving the quality of the recovered signal at the receiving end.

[0094] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 8, the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 7, wherein the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 8 training symbols 8 , and in combination of 2 polarization directions, there are 2 32 possibilities, and here the possibilities of values of 8 training symbols are provided, in which the autocorrelation and cross-correlation characteristics in each polarization direction are better.

[0095] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 10, the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 8, wherein the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 10 training symbols 10 , and in combination of 2 polarization directions, there are 2 40 possibilities, and here the possibilities of values of 10 training symbols are provided, in which the autocorrelation and cross-correlation characteristics in each polarization direction are better.

[0096] In some possible implementation, in one polarization direction, the number of training symbols in each of the plurality of subframes is 12, the values of the 12 training symbols in the first polarization direction and the values of the 12 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following as shown in Table 9, wherein the first polarization direction can also be referred to as X polarization direction, and the second polarization direction can also be referred to as Y polarization direction. It should be understood that in one polarization direction, there are 4 possibilities of values of 12 training symbols 12 , and in combination of 2 polarization directions, there are 2 48 possibilities, and here the possibilities of values of 12 training symbols are provided, in which the autocorrelation and cross-correlation characteristics in each polarization direction are better.

[0097] In some possible implementation, N PG = 128, the interval of inserting pilot symbols in the subframe is increased, which is equivalent to reducing the number of added symbols in the data frame, and the transmission redundancy is smaller.

[0098] In some possible implementation manners, the data frame adopts a symbol mapping manner of Quadrature Phase Shift Keying (QPSK), and A=-1 or 1; or the data frame adopts a symbol mapping manner of 16-ary Quadrature Amplitude Modulation (16QAM), and A=-3 or 3.

[0099] In some possible implementation manners, in one polarization direction, the subframe includes N TS training symbols, and a total of 113+N TS -1 symbols in the subframe satisfy a direct current balance, which is beneficial to improving the quality of signal recovery at the receiving end.

[0100] In some possible implementation manners, in one polarization direction, the subframe includes N TS training symbols, and a total of 113+N TS -1 symbols in the subframe satisfy a direct current balance, which is beneficial to improving the quality of signal recovery at the receiving end.

[0101] In some possible implementation manners, the subframe arranged at the first position in the data frame is a first type of subframe, the first type of subframe further includes a frame synchronization symbol, a reserved symbol and a pre-formation symbol, and in the first type of subframe, the training symbol is located before the frame synchronization symbol, the frame synchronization symbol is located before the reserved symbol, and the reserved symbol is located before the pre-formation symbol. The data frame includes at least one second type of subframe, the second type of subframe further includes a pre-formation symbol, and in the second type of subframe, the training symbol is located before the pre-formation symbol.

[0102] In a fifth aspect, an embodiment of the present application provides a chip, which is configured to execute the method described in any of the embodiments of the first aspect or the second aspect.

[0103] In a sixth aspect, an embodiment of the present application provides an optical module, which includes a processor and an interface. The interface is configured to transmit and receive signals, and the processor is configured to execute the method described in any of the embodiments of the first aspect or the second aspect. For example, the interface is configured to transmit a signal from the processor or transmit a received signal to the processor.

[0104] In a seventh aspect, an embodiment of the present application provides a network device. The transmitting device includes a host-side device and an optical module as described in the sixth aspect. For example, the optical module is configured to convert an electrical signal from the host-side device into an optical signal and transmit the optical signal. For another example, the optical module is configured to convert a received optical signal into an electrical signal and transmit the electrical signal to the host-side device.

[0105] In an eighth aspect, the embodiments of the present application provide a communication system, which comprises a plurality of network devices as described in the seventh aspect, and the network devices are configured to transmit optical signals to each other.

[0106] In a ninth aspect, the embodiments of the present application provide a computer readable storage medium, which stores instructions, and the instructions are configured to be executed by a computer to implement the method as described in any of the embodiments of the first aspect or the second aspect.

[0107] In a tenth aspect, the embodiments of the present application provide a computer program product, which comprises program instructions, and the program instructions are configured to be executed by a computer to implement the method as described in any of the embodiments of the first aspect or the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0108] FIG. 1 is a schematic diagram of a communication system to which the embodiments of the present application are applied;

[0109] FIG. 2(a) is a schematic diagram of an implementation of a transmitter DSP processor in the embodiments of the present application;

[0110] FIG. 2(b) is a schematic diagram of another implementation of a transmitter DSP processor in the embodiments of the present application;

[0111] FIG. 2(c) is a schematic diagram of yet another implementation of a transmitter DSP processor in the embodiments of the present application;

[0112] FIG. 2(d) is a schematic diagram of still another implementation of a transmitter DSP processor in the embodiments of the present application;

[0113] FIG. 3 is a schematic diagram of a data transmission method in the embodiments of the present application;

[0114] FIG. 4 is a schematic diagram of a structure of a superframe in the embodiments of the present application;

[0115] FIG. 5 is a schematic diagram of a structure of a subframe in the embodiments of the present application;

[0116] FIG. 6 is a schematic diagram of a constellation in the embodiments of the present application;

[0117] FIG. 7 is a schematic diagram of a simulated symbol data stream in the embodiments of the present application;

[0118] FIG. 8 is a schematic diagram of an implementation of a superframe and a subframe in the embodiments of the present application;

[0119] FIG. 9 is a schematic diagram of an autocorrelation characteristic and a cross-correlation characteristic corresponding to a pilot symbol sequence in the embodiments of the present application;

[0120] FIG. 10 is a schematic diagram of an autocorrelation characteristic and a cross-correlation characteristic corresponding to a training symbol sequence in the embodiments of the present application;

[0121] Fig. 11 is a schematic diagram of a structure of a data transmission apparatus according to an embodiment of the present application;

[0122] Fig. 12 is a schematic diagram of another structure of a data transmission apparatus according to an embodiment of the present application;

[0123] Fig. 13 is a schematic diagram of a structure of an optical module according to an embodiment of the present application;

[0124] Fig. 14 is a schematic diagram of a structure of a network device according to an embodiment of the present application. DETAILED DESCRIPTION

[0125] The embodiments of the present application provide a data transmission method, apparatus and system, which has less redundancy and better correlation of added preset symbol sequence, and is beneficial to improve the quality of recovered signal at the receiving end, and can be well applied to various coherent transmission scenarios.

[0126] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not intended to limit a specific order or sequence. It should be understood that the above-mentioned terms can be interchanged as appropriate, so that the embodiments described in the present application can be implemented in an order other than that described in the present application. In addition, the terms "include" and "have" 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 does not have to be limited to only those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to the process, method, product or device. It should be understood that for the tables marked with serial numbers in the present application, the serial numbers are only used to distinguish different value combinations provided in the tables, and do not limit the contents in the tables. For example, if there are 10 serial numbers in the table, it means that the table provides 10 possible value combinations.

[0127] Figure 1 is a schematic diagram of a communication system to which embodiments of the present application can be applied. As shown in Figure 1, at the transmitting end, a data stream to be transmitted is provided by a source. A forward error correction (FEC) encoder receives the data stream and performs FEC encoding thereon. The FEC encoding obtains code word information in which check bits and information bits are combined, and the code word information is sent to a transmitting end digital signal processing (DSP) processor for framing. The code word information is transmitted through a channel to a receiving end. After the receiving end receives a distorted signal due to noise or other impairments in the channel, the distorted signal is sent to a receiving end DSP processor for dispersion compensation, synchronization, phase recovery, etc. Then, the distorted signal is decoded by an FEC decoder to recover the original data and sent to a sink. The framing described above can also be referred to as DSP framing.

[0128] Figure 2(a) is a schematic diagram of an implementation of the transmitter DSP processor in the embodiments of the present application. As shown in Figure 2(a), in one possible implementation, the transmitter DSP processor performs dual-polarization symbol mapping on the received data sequence. Generally, the received data sequence is the information sequence and the check sequence obtained by FEC encoding. The dual-polarization symbol mapping includes symbol mapping and polarization distribution. The symbol mapping includes, but is not limited to, Quadrature Amplitude Modulation (QAM) and Quadrature Phase Shift Keying (QPSK). Generally, the QAM modulation (also referred to as symbol mapping) includes symbol mapping of input bits to obtain QAM symbols, and polarization distribution of the QAM symbols to obtain dual-polarization (DP) symbols, i.e., DP-QAM symbols, such as DP-4QAM (also referred to as DP-QPSK), DP-16QAM, DP-32QAM, and DP-64QAM, etc. It should be understood that the symbol mapping generally uses gray mapping to map multiple bits to one QAM symbol, and the symbol mapping is also simply referred to as gray mapping. For ease of introduction, hereinafter, two polarization directions are uniformly denoted as X polarization direction and Y polarization direction, wherein the X polarization direction and the Y polarization direction are orthogonal to each other, and the X polarization direction can also be referred to as the first polarization direction, and the Y polarization direction can also be referred to as the second polarization direction. It should be understood that the X polarization direction and the Y polarization direction are not two specified polarization directions, but two arbitrary orthogonal polarization directions. Further, the transmitter DSP processor performs framing processing on a certain number of dual-polarization symbols, specifically, obtains a pre-framing dual-polarization symbol sequence containing multiple dual-polarization symbols, inserts at least one symbol sequence of a Frame Alignment Word Sequence (FAW Sequence), a training symbol sequence, a reserved symbol sequence, and a pilot symbol sequence in the X polarization direction and the Y polarization direction, respectively, to obtain a post-framing dual-polarization symbol sequence. The inserted symbol sequence can also be referred to as a preset symbol sequence.

[0129] In this embodiment, the pre-framing dual polarization symbol is also called a payload symbol, which includes the symbols obtained by symbol mapping of the FEC encoded information and the check bits (called information symbols and check symbols). The sequence of post-framing dual polarization symbols is called a data frame, which can also be called a frame or a DSP frame. For ease of introduction, the post-framing dual polarization symbol sequence is uniformly called a data frame in the embodiments of this application. The frame synchronization symbol is used for frame synchronization alignment, the training symbol is used for link training, the pilot symbol is used for carrier phase recovery, and the reserved symbol is used for future use and innovation. The value of the reserved symbol can be known and constant, or randomized. The value of the reserved symbol can also be called a pattern. In some specific embodiments, the DSP frame contains multiple subframes, and the DSP frame is called a super-frame. In another specific embodiment, the DSP frame can also be called a multi-frame, and the reserved symbol can also be called a fixed stuff (FS), and the frame synchronization symbol can also be called a multi-frame alignment signal (MFAS).

[0130] In the embodiments of this application, the value of each training symbol and each pilot symbol is one of the four complex numbers -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number and j represents an imaginary unit. Here, Aj can also be written as A×j. In some scenarios, the imaginary unit can 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.

[0131] It should be noted that the inserted symbol sequence is not exactly the same in the X polarization direction and the Y polarization direction. That is, the values of the inserted symbols in the X polarization direction and the Y polarization direction are not the same at least at one position, to avoid the problem that the receiving end cannot distinguish between the two polarization directions in actual transmission. For example, the sequence of 8 training symbols in the X polarization direction is -A-Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, and the sequence of 8 training symbols in the Y polarization direction in the same order cannot be exactly the same as that in the X polarization direction, and can be -A+Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj.

[0132] It should be understood that one dual-polarization symbol can be represented by two symbols, one 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 by 16QAM modulation can be represented by any one of the following 16 complex numbers: ±1±1j, ±1±3j, ±3±1j and ±3±3j, where ± means taking a positive value or a negative value, such as ±3 means 3 or -3. For another example, a symbol obtained by QPSK modulation can be represented by any one of the following 4 complex numbers: ±1±1j. In some specific applications, the real and imaginary parts are normalized, but the essence does not change.

[0133] It should be noted that a sequence of N0 dual-polarization symbols can be completely represented by two complex number sequences of length N0, one representing the symbols in the X polarization direction and the other representing the symbols in the Y polarization direction. Each complex number sequence of length N0 is represented by a real component sequence (also referred to as an I sequence) of length N0 and an imaginary component sequence (also referred to as a Q sequence) of length N0, N0 being an integer greater than 1. Therefore, there are four different types of sequences, including an X polarization I sequence, an X polarization Q sequence, a Y polarization I sequence and a Y polarization Q sequence. The X polarization I sequence is also referred to as an X I component, the X polarization Q sequence is also referred to as an X Q component, the Y polarization I sequence is also referred to as a Y I component, and the Y polarization Q sequence is also referred to as a Y Q component.

[0134] It should be noted that after the dual-polarization symbol mapping and framing operation, a dual-polarization symbol data stream to be transmitted is obtained. The dual-polarization symbol data stream to be transmitted can be represented by two symbol data streams, the first being a symbol data stream of the dual-polarization symbol data stream in the X polarization direction and the second being a symbol data stream of the dual-polarization symbol data stream in the Y polarization direction. Alternatively, the dual-polarization symbol data stream to be transmitted can also be represented by four data streams, the first being a data stream of the I component of the dual-polarization symbol stream in the X polarization direction (referred to as an X I data stream), the second being a data stream of the Q component of the dual-polarization symbol stream in the X polarization direction (referred to as an X Q data stream), the third being a data stream of the I component of the dual-polarization symbol stream in the Y polarization direction (referred to as a Y I data stream), and the fourth being a data stream of the Q component of the dual-polarization symbol stream in the Y polarization direction (referred to as a Y Q data stream).

[0135] It should be understood that in the dual polarization symbol mapping and framing operation shown in Fig. 2(a), the framing (also referred to as DSP framing) is performed after the dual polarization symbol mapping, i.e., the framing is performed on a symbol basis. In the following, several other possible implementation manners of the sending DSP processor are given, in which the framing is performed before the dual polarization symbol mapping, i.e., the framing is performed on a bit basis.

[0136] Fig. 2(b) is a schematic diagram of another implementation manner of the sending DSP processor in the embodiment of the present application. As shown in Fig. 2(b), the framing is performed before the dual polarization symbol mapping. Specifically, a pre-framing bit sequence containing a plurality of bits is obtained, a preset bit sequence is inserted and dual polarization symbol mapping is performed to obtain a post-framing dual polarization symbol sequence. The preset bit sequence is mapped to a preset symbol sequence by the dual polarization symbol mapping, and the preset bit sequence is also referred to as the bit corresponding to the preset symbol sequence. It should be understood that the post-framing dual polarization symbol sequence obtained by using the pre-framing bit sequence in the implementation manner shown in Fig. 2(b) is the same as the post-framing dual polarization symbol sequence obtained by using the pre-framing bit sequence in the implementation manner shown in Fig. 2(a).

[0137] Fig. 2(c) is a schematic diagram of still another implementation manner of the sending DSP processor in the embodiment of the present application. As shown in Fig. 2(c), the framing is performed before the dual polarization symbol mapping. Specifically, two pre-framing bit sequences containing a plurality of bits are respectively obtained, a first preset bit sequence and a second preset bit sequence are respectively inserted into the first pre-framing bit sequence and the second pre-framing bit sequence, and dual polarization symbol mapping is performed to obtain a post-framing dual polarization symbol sequence. The first preset bit sequence is mapped to a preset symbol sequence in the X polarization direction by the symbol mapping, and the second preset bit sequence is mapped to a preset symbol sequence in the Y polarization direction by the symbol mapping. The first preset bit sequence is also referred to as the bit corresponding to the preset symbol sequence in the X polarization direction, and the second preset bit sequence is also referred to as the bit corresponding to the preset symbol sequence in the Y polarization direction. It should be understood that the post-framing dual polarization symbol sequence obtained by using the pre-framing bit sequence in the implementation manner shown in Fig. 2(c) is the same as the post-framing dual polarization symbol sequence obtained by using the pre-framing bit sequence in the implementation manner shown in Fig. 2(a).

[0138] Figure 2(d) is a schematic diagram of another embodiment of the transmitter DSP processor in the present application. As shown in Figure 2(d), framing is performed before dual polarization symbol mapping. Specifically, four framing pre-bit sequences containing a plurality of bits are obtained, a first preset bit sequence, a second preset bit sequence, a third preset bit sequence and a fourth preset bit sequence are inserted into the first framing pre-bit sequence, the second framing pre-bit sequence, the third framing pre-bit sequence and the fourth framing pre-bit sequence respectively, and dual polarization symbol mapping is performed to obtain a framing post-dual polarization symbol sequence. The first preset bit sequence is mapped to obtain an I path component of a preset symbol sequence in the X polarization direction, the second preset bit sequence is mapped to obtain a Q path component of the preset symbol sequence in the X polarization direction, the third preset bit sequence is mapped to obtain an I path component of a preset symbol sequence in the Y polarization direction, and the fourth preset bit sequence is mapped to obtain a Q path component of the preset symbol sequence in the Y polarization direction. The first preset bit sequence is also referred to as a bit corresponding to the I path component of the preset symbol sequence in the X polarization direction, the second preset bit sequence is also referred to as a bit corresponding to the Q path component of the preset symbol sequence in the X polarization direction, the third preset bit sequence is also referred to as a bit corresponding to the I path component of the preset symbol sequence in the Y polarization direction, and the fourth preset bit sequence is also referred to as a bit corresponding to the Q path component of the preset symbol sequence in the Y polarization direction. It should be understood that the framing post-dual polarization symbol sequence obtained by using the embodiment shown in Figure 2(d) for the framing pre-bit sequence is the same as the framing post-dual polarization symbol sequence obtained by using the embodiment shown in Figure 2(a) for the framing pre-bit sequence. I Q I Q It should be understood that the framing post-dual polarization symbol sequence obtained by using the embodiment shown in Figure 2(d) for the framing pre-bit sequence is the same as the framing post-dual polarization symbol sequence obtained by using the embodiment shown in Figure 2(a) for the framing pre-bit sequence.

[0139] It should be understood that the framing post-dual polarization symbol sequence obtained by using the embodiment shown in Figure 2(d) for the framing pre-bit sequence is the same as the framing post-dual polarization symbol sequence obtained by using the embodiment shown in Figure 2(a) for the framing pre-bit sequence.

[0140] Figure 3 is a schematic diagram of a data transmission method in an embodiment of the present application. As shown in Figure 3, the data transmission method comprises the following steps.

[0141] 101. The transmitter obtains a data frame.

[0142] ​​​It should be noted that the present application does not limit the specific implementation of the data frame, for example, the above-mentioned double polarization symbol mapping and framing manner of FIG. 2(a), FIG. 2(b), FIG. 2(c) or FIG. 2(d) can be adopted, of course, other similar double polarization symbol mapping and framing manner is also applicable to the present scheme, which will not be introduced one by one here. It should be understood that the data frame includes symbols in two polarization directions, and the structure of the data frame in the two polarization directions is similar, for example, the data frame includes a symbol sequence in the X polarization direction and a symbol sequence in the Y polarization direction, and the structure of the data frame will be introduced below taking one of the polarization directions as an example.

[0143] FIG. 4 is a schematic diagram of a structure of a superframe in an embodiment of the present application. As shown in FIG. 4, the superframe includes N SF subframes, each of which includes N S symbols, so that the superframe includes N F symbols, N F =N SF ×N S , N S and N SF are integers greater than 1. Among them, the subframes in the superframe are divided into two categories, which are referred to as the first type of subframe and the second type of subframe here, which will be introduced below.

[0144] FIG. 5 is a schematic diagram of a structure of a subframe in an embodiment of the present application. As shown in (a) of FIG. 5, the structure of the first type of subframe, the first type of subframe includes training symbols, pilot symbols, frame synchronization symbols, reserved symbols and framing front symbols (also referred to as payload symbols). Generally, the first type of subframe is the subframe arranged at the first position in the superframe, of course, it is not excluded that it is arranged at other positions in the superframe, for example, the first type of subframe can also be the subframe arranged at the last position in the superframe. In the first type of subframe, typically, the training symbols are located before the frame synchronization symbols, the frame synchronization symbols are located before the reserved symbols, and the reserved symbols are located before the framing front symbols. The subframes other than the first type of subframe in the superframe are the second type of subframe, as shown in (b) of FIG. 5, the second type of subframe is different from the first type of subframe, the second type of subframe includes training symbols, pilot symbols and framing front symbols (also referred to as payload symbols), but does not include frame synchronization symbols and reserved symbols. In the second type of subframe, typically, the training symbols are located before the framing front symbols.

[0145] For the first type of subframe and the second type of subframe, each subframe includes training symbols and pilot symbols, the training symbols can be used for link training and subframe synchronization, and the pilot symbols are used for carrier phase recovery. In one polarization direction, the number of training symbols in the subframe is denoted as N TS , and the number of pilot symbols in the subframe is denoted as N PS , N TS and N PSare integers greater than 1. It is noted that one symbol in the subframe is both a training symbol and a pilot symbol, i.e., the symbol indicated by the dashed box in FIG. 5. N TS training symbols include the symbol indicated by the dashed box, N PS pilot symbols also include the symbol indicated by the dashed box. Further, N TS + N PS is greater than or equal to 5, and N TS + N PS is an odd number. Typically, N TS consecutive training symbols are arranged starting from the beginning of the subframe, and the symbol at the beginning of the N TS consecutive training symbols is both a training symbol and a pilot symbol. That is, the first symbol of the subframe is the first symbol of the training symbol sequence and also the first symbol of the pilot symbol sequence. In other words, the first symbol of the training symbol sequence is also the first symbol of the pilot symbol sequence, and the first symbol of the training symbol sequence has the same value as the first symbol of the pilot symbol sequence. Of course, the symbol indicated by the dashed box in FIG. 5 can be any one of the N TS training symbols, which is not limited in the present application.

[0146] For each subframe in the superframe, each N PG consecutive symbols in the subframe include one pilot symbol at a fixed position. As shown in FIG. 5, N PG is 128. It is understood that since the position of the pilot symbol in each N PG consecutive symbols is fixed, the two consecutive pilot symbols in the subframe are equally spaced. Typically, the pilot symbol is at the beginning of each N PG consecutive symbols, of course, the pilot symbol can be at any position in each N PG consecutive symbols, which is not limited herein.

[0147] It should be noted that the frame synchronization symbol is used for synchronization between superframes, which can be used together with the training symbol for synchronization between superframes, or can be used together with the pilot symbol to achieve the synchronization function. It should be understood that the frame synchronization symbol is arranged continuously, and can be next to the training symbol, as shown in FIG. 5. In addition, there can be one or more symbol intervals between the frame synchronization symbol and the training symbol. After a plurality of frame synchronization symbols, a plurality of reserved symbols are usually provided, which can be reserved for future other uses, and the reserved symbols should be randomized and can not be symbols on the constellation of the used modulation format. Of course, in some applications, the reserved symbols can also be symbols on the constellation of the used modulation format. The reserved symbols can also have a part that is fixed as other uses, such as optical signal to noise ratio (OSNR) measurement, end-to-end (E2E) latency measurement, etc. The reserved symbols can also be located in one of the plurality of second type subframes, and the present application does not make any limitation. The remaining symbols are framing pre-symbol (i.e. payload symbol) containing information and check symbols, wherein the pilot symbol does not overlap with the reserved symbol, and the pilot symbol does not overlap with the framing pre-symbol. That is, there is no symbol that is both a pilot symbol and a framing pre-symbol, and there is no symbol that is both a pilot symbol and a reserved symbol.

[0148] In some specific applications, taking 16QAM symbol mapping as an example, the values of the 16 constellation points (also called symbols) on the corresponding 16QAM constellation are {±1±1j, ±1±3j, ±3±1j, ±3±3j}. FIG. 6 is a schematic diagram of a constellation in an embodiment of the present application. The constellation 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. As shown in the (a) example of FIG. 6, the hollow circles represent the outermost 4 constellation points in the constellation, i.e. symbols -3-3j, -3+3j, 3-3j, and 3+3j, and the vertical line circles represent the innermost 4 constellation points in the constellation, i.e. symbols -1-1j, -1+1j, 1-1j, and 1+1j. The (b) example of FIG. 6 gives a specific 16QAM symbol mapping mode, one 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, and 1101 is mapped to 1-1j.

[0149] Typically, for 16QAM symbol mapping, A = 3 or -3 is selected so that the sensitivity of the training symbol or pilot symbol is better. For QPSK symbol mapping, the four constellation points (also called symbols) on the constellation diagram are {±1±1j}, and A = 1 or -1 is selected.

[0150] It should be noted that the symbols on the constellation diagram can also be compressed, and the value of A is also compressed accordingly. Taking 16QAM as an example, the 16 symbols on the 16QAM constellation diagram are power normalized, and at this time, the value is The value of A is or

[0151] It should be noted that each frame synchronization symbol is one of the four complex numbers -A FAW -A FAW j, -A FAW +A FAW j, A FAW -A FAW j, and A FAW +A FAW j, A FAW is a real number, where A FAW may be equal to A or not equal to A. Typically, A FAW is equal to A, and at this time, the operation of inserting the training symbol, the pilot symbol, and the frame synchronization symbol in the framing operation is relatively simple.

[0152] It should be noted that in one subframe, the sum of the real parts of the total N TS +N PS -1 symbols including all the training symbols and all the pilot symbols in one polarization direction is 0, and the sum of the imaginary parts of the total N TS +N PS -1 symbols including all the training symbols and all the pilot symbols in one polarization direction is 0, so that DC balance can be achieved, which is beneficial to the quality of the recovered signal at the receiving end. It should be understood that since the training symbol sequence and the pilot symbol sequence in the subframe share one symbol, when combining the training symbol sequence and the pilot symbol sequence to calculate the number of symbols, the shared symbol that is counted repeatedly needs to be subtracted, that is, the training symbol sequence and the pilot symbol sequence share N TS +N PS -1 symbols.

[0153] 102、The sending end sends a data frame to the receiving end.

[0154] Figure 7 is a schematic diagram of analog symbol data streams in embodiments of the present application. As shown in Figure 7, in some possible scenarios, the digital symbol data stream after digital to analog conversion (DAC) can be regarded as four analog symbol data streams, which are marked as X I , X Q , Y I and Y Q , respectively. Among them, the X I analog symbol data stream and the X Q analog symbol data stream correspond to the real part sequence data stream and the imaginary part sequence data stream in the X polarization direction, respectively. The Y I analog symbol data stream and the Y Q analog symbol data stream correspond to the real part sequence data stream and the imaginary part sequence data stream in the Y polarization direction, respectively. It should be understood that the X polarization direction and the Y polarization direction (also referred to as the H polarization direction and the V polarization direction) are two mutually orthogonal polarization directions, and there are two mutually orthogonal phase channels, I (In-phase) and Q (Quadrature), in each polarization direction, which correspond to the real part sequence data stream and the imaginary part sequence data stream, respectively.

[0155] 103. The receiving end performs signal processing on the received data frame.

[0156] It should be understood that the receiving end receives the data frame after channel transmission, 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 sending end, for example, the data frame received by the receiving end is not aligned with the data frame sent by the sending end, and the receiving end needs to perform frame synchronization according to the frame synchronization symbol or the training symbol. The specific operation of the receiving end after receiving the data frame will not be described in detail, and can be referred to the system structure diagram shown in Figure 1, for example, the signal processing (signal processing) of the received data frame by the receiving end DSP processor includes dispersion compensation, synchronization, phase recovery, etc.

[0157] Some specific examples are introduced below based on the data frame (superframe) provided in embodiments of the present application. In particular, it is considered that the proposed pilot symbol is obtained based on 116 pilot symbols in 400ZR or 114 pilot symbols in 800ZR. For example, it is considered that N PS = 113. Table 1 gives some parameter combinations of data frames (superframes), including the number of symbols before framing N CW , the number of subframes N SF , the number of symbols in each subframe N S , the number of symbols in the superframe N F , the number of training symbols NTS , the number N of frame synchronization symbols FAW , the number N of reserved symbols RES , and the number N of frame synchronization symbols FAW and the number N of reserved symbols RES Here, in one polarization direction, N PS = 113 pilot symbols are contained in each subframe, and the first symbol in every continuous N PG = 128 symbols in the subframe is a pilot symbol.

[0158] Table 1

[0159] It should be noted that in some specific applications, in order to facilitate compatibility with 400ZR and 800ZR applications, N FAW = 22 is considered, and the specific value of N FAW + N RES can be obtained in combination with the value of N RES . For example, as shown in Table 1, No. 1, N FAW + N RES = 96, in combination with N FAW = 22, N RES = 74 can be obtained. For another example, as shown in Table 1, No. 2, N FAW + N RES = 72, in combination with N FAW = 22, N RES = 50 can be obtained. It should be understood that the more the number of training symbols in the subframe, the fewer the number of reserved symbols. Therefore, the number of training symbols in the subframe is selected to be 8, 10 or 12, so that more reserved symbols can be reserved in the subframe, which is beneficial to future use and innovation.

[0160] In some specific embodiments, the N PS = 113 pilot symbols are the first 113 pilot symbols of the existing 114 pilot symbols of 800ZR, that is, the last 1 pilot symbol is removed. At this time, it can be considered that in one polarization direction, the N PS = 113 pilot symbols are generated by a generating polynomial and a seed. The generating polynomial is x 10 + x 7 + x 3 + x + 1, and the seeds in hexadecimal representation in the two polarization directions are 0x34E and 0x084. The respective 113 pilot symbols in the two polarization directions are shown in the following Table 2:

[0161] Table 2

[0162] It should be noted that the autocorrelation and cross-correlation characteristics of the pilot symbol sequence given in Table 2 are both good (the normalized amplitude of the sidelobe value of the periodic autocorrelation function of any one polarization direction is not greater than 0.185, and the normalized amplitude of the periodic cross-correlation function value of the pilot symbols in different polarization directions is not greater than 0.195).

[0163] It should be noted that in any one polarization direction, N PS = 113 pilot symbols and N TS training symbols combined together have a total of N TS +N PS -1 symbols satisfying DC balance. Considering the 113 pilot symbols in Table 2 above, the N TS training symbols used need to satisfy the following constraints:

[0164] 1) In the X polarization direction, the sum of the symbols of the N TS training symbols is 2A+2Aj. For example, when A = 1, 2A+2Aj is 2+2j; when A = 3, 2A+2Aj is 6+6j.

[0165]

[0166] 2) In the Y polarization direction, the sum of the symbols of the N TS training symbols is -2A. For example, when A = 1, -2A is -2; when A = 3, -2A is -6.

[0167] 3) N TS is even.

[0168] The specific values of the N TS training symbols are considered below, respectively, when N TS = 8 or 10 or 12.

[0169] Considering the 113 pilot symbols in Table 2 above, and the number of training symbols in each subframe is N TS = 8. Table 3 below gives some specific values of the training symbols.

[0170] Table 3

[0171] It should be understood that in one polarization direction, the number of possibilities for the values of the 8 training symbols is 4 8 , so in total there are 2 32 ​Table 3 provides the possibilities of the values of the 8 training symbols in each polarization direction, which have good autocorrelation and cross-correlation characteristics. It should be noted that the sequence autocorrelation and cross-correlation characteristics of the pilot symbols given in Table 2 are good, and the sequence autocorrelation and cross-correlation characteristics of the training symbols corresponding to any one of the serial numbers in Table 3 are good (the normalized amplitude of the non-periodic autocorrelation function side lobe of any one polarization direction is not greater than 0.26, and the normalized amplitude of the non-periodic cross-correlation function value of the training symbols in different polarization directions is not greater than 0.46). The first pilot symbol of the 113 pilot symbols is also a training symbol. The 8 training symbols and the 113 pilot symbols combined together in each subframe have a total of 8+113-1=120 symbols, which can also satisfy the direct current balance, facilitate the recovery of the signal at the receiving end, and improve the quality of the recovered signal.

[0172] Consider using the 113 pilot symbols in Table 2 above, and the number of training symbols in each subframe is N TS = 10. Table 4 below gives the values of some specific training symbols.

[0173] Table 4

[0174] It should be understood that in one polarization direction, there are 4 10 possibilities of the values of the 10 training symbols, and there are a total of 2 40 possibilities when the two polarization directions are combined together, and Table 4 provides the possibilities of the values of the 10 training symbols in each polarization direction, which have good autocorrelation and cross-correlation characteristics. It should be noted that the sequence autocorrelation and cross-correlation characteristics of the pilot symbols given in Table 2 are good, and the sequence autocorrelation and cross-correlation characteristics of the training symbols corresponding to any one of the serial numbers in Table 4 are good (the normalized amplitude of the non-periodic autocorrelation function side lobe of any one polarization direction is not greater than 0.23, and the normalized amplitude of the non-periodic cross-correlation function value of the training symbols in different polarization directions is not greater than 0.45). The first pilot symbol of the 113 pilot symbols is also a training symbol. The 10 training symbols and the 113 pilot symbols combined together in each subframe have a total of 10+113-1=122 symbols, which can also satisfy the direct current balance, facilitate the recovery of the signal at the receiving end, and improve the quality of the recovered signal.

[0175] Consider using the 113 pilot symbols in Table 2 above, and the number of training symbols in each subframe is N TS = 12. Table 5 below gives the values of some specific training symbols.

[0176] Table 5

[0177] It should be understood that in one polarization direction, there are 4 12 2 polarization directions together, there are 2 48 possibilities, and Table 5 provides the possibilities of the values of the 12 training symbols in each polarization direction, which have good autocorrelation and cross-correlation characteristics. It should be noted that the sequence of the pilot symbols in Table 2 has good autocorrelation and cross-correlation characteristics, and the sequence of the training symbols corresponding to any one of the serial numbers in Table 5 has good autocorrelation and cross-correlation characteristics (the normalized amplitude of the sidelobe value of the aperiodic autocorrelation function in any one polarization direction is not greater than 0.2, and the normalized amplitude of the aperiodic cross-correlation function value of the training symbols in different polarization directions is not greater than 0.3). The first pilot symbol of the 113 pilot symbols is also a training symbol. The combination of the 12 training symbols and the 113 pilot symbols in each subframe together has 12+113-1=124 symbols, which can also satisfy the direct current balance, which is conducive to improving the signal recovery at the receiving end and improving the quality of the recovered signal.

[0178] In some other embodiments, the N PS =113 pilot symbols are the first 113 pilot symbols of the existing 116 pilot symbols of 400ZR, that is, the last 3 pilot symbols are removed. At this time, it can be considered that in one polarization direction, the N PS =113 pilot symbols are generated by a generating polynomial and a seed. The generating polynomial is x 10 +x 8 +x 4 +x 3 +1, and the seeds in hexadecimal representation in the corresponding two polarization directions are 0x19E and 0x0D0. The respective 113 pilot symbols in the two polarization directions are shown in the following Table 6:

[0179] Table 6

[0180] It should be noted that the sequence of the pilot symbols in Table 6 has good autocorrelation and cross-correlation characteristics (the normalized amplitude of the sidelobe value of the periodic autocorrelation function in any one polarization direction is not greater than 0.183, and the normalized amplitude of the periodic cross-correlation function value of the pilot symbols in different polarization directions is not greater than 0.206).

[0181] It should be noted that in any one polarization direction, the N PS =113 pilot symbols and the N TS training symbols together have a total of N TS+N PS -1 symbol satisfies DC Balance. Considering the 113 pilot symbols in Table 6 above, the N TS training symbols employed need to satisfy the following constraints:

[0182] 1) In the first polarization direction, the sum of the symbols of the N TS training symbols is 2A+2Aj. For example, when A=1, 2A+2Aj is 2+2j;

[0183] and when A=3, 2A+2Aj is 6+6j.

[0184] 2) In the second polarization direction, the sum of the symbols of the N TS training symbols is 2A-2Aj. For example, when A=1, 2A-2Aj is 2-2j;

[0185] and when A=3, 2A-2Aj is 6-6j.

[0186] 3) N TS is even.

[0187] The following considers the specific values of the N TS training symbols for N TS =8 or 10 or 12, respectively.

[0188] Considering the 113 pilot symbols in Table 6 above, and N TS =8 training symbols in each subframe. Table 7 below gives some specific values of the training symbols.

[0189] Table 7

[0190] It should be understood that in one polarization direction, there are 4 8 possible values for the 8 training symbols, and thus in combination with the 2 32The table 7 provides the possibilities of the values of the 8 training symbols with good autocorrelation and cross-correlation characteristics in each polarization direction. It should be noted that the sequence autocorrelation and cross-correlation characteristics of the pilot symbols given in the table 6 are good, and the sequence autocorrelation and cross-correlation characteristics of the training symbols corresponding to any one of the serial numbers in the table 7 are good (the normalized amplitude of the non-periodic autocorrelation function side lobe of any one polarization direction is not greater than 0.26, and the normalized amplitude of the non-periodic cross-correlation function value of the training symbols in different polarization directions is not greater than 0.46). The first pilot symbol of the 113 pilot symbols is also a training symbol. The 8 training symbols and the 113 pilot symbols combined together in each subframe are a total of 8+113-1=120 symbols, which can also satisfy the direct current balance, facilitate the recovery of the signal at the receiving end, and improve the quality of the recovered signal.

[0191] It is considered to use the 113 pilot symbols in the above table 6, and the number of training symbols in each subframe is N TS = 10. The table 8 below gives the values of some specific training symbols.

[0192] Table 8

[0193] It should be understood that in one polarization direction, the possibility of the values of the 10 training symbols is 4 10 , and the total number of possibilities of 2 40 polarization directions combined together is 2 The table 8 provides the possibilities of the values of the 10 training symbols with good autocorrelation and cross-correlation characteristics in each polarization direction. It should be noted that the sequence autocorrelation and cross-correlation characteristics of the pilot symbols given in the table 6 are good, and the sequence autocorrelation and cross-correlation characteristics of the training symbols corresponding to any one of the serial numbers in the table 8 are good (the normalized amplitude of the non-periodic autocorrelation function side lobe of any one polarization direction is not greater than 0.23, and the normalized amplitude of the non-periodic cross-correlation function value of the training symbols in different polarization directions is not greater than 0.45). The first pilot symbol of the 113 pilot symbols is also a training symbol. The 10 training symbols and the 113 pilot symbols combined together in each subframe are a total of 10+113-1=122 symbols, which can also satisfy the direct current balance, facilitate the recovery of the signal at the receiving end, and improve the quality of the recovered signal.

[0194] It is considered to use the 113 pilot symbols in the above table 6, and the number of training symbols in each subframe is N TS = 12. The table 9 below gives the values of some specific training symbols.

[0195] Table 9

[0196] It should be understood that in one polarization direction, the possibility of the values of the 12 training symbols is 4 12, 2 polarizations together have 2 48 Table 9 provides the possibility of the value of 12 training symbols with good autocorrelation and cross-correlation characteristics in each polarization direction. It should be noted that the sequence of pilot symbols in Table 6 has good autocorrelation and cross-correlation characteristics, and the sequence number of any one in Table 9 corresponds to the training symbol with good autocorrelation and cross-correlation characteristics (the normalized amplitude of the non-periodic autocorrelation function of any one polarization direction is not greater than 0.2, and the normalized amplitude of the non-periodic cross-correlation function of the training symbols in different polarizations is not greater than 0.3). The first pilot symbol of the 113 pilot symbols is also a training symbol. The combination of the 10 training symbols and the 113 pilot symbols in each subframe together has 12+113-1=124 symbols, which can also satisfy the direct current balance, facilitate the recovery of the signal at the receiving end, and improve the quality of the recovered signal.

[0197] The embodiments of the present application provide several specific superframe formats, which are described as follows:

[0198] Embodiment one: The symbols before framing (also referred to as payload symbols) are encoded to about 15.3% OFEC encoding, the number of symbols before framing is 172032, and each continuous 128 symbols in the subframe includes one pilot symbol, and the corresponding N SF , N TS , N PS , N FAW , N RES , N S , N F , OH and other parameters are shown in Table 10.

[0199] Table 10

[0200] Fig. 8 is a schematic diagram of one embodiment of a superframe and a subframe in the embodiments of the present application. As shown in (a) of Fig. 8, the superframe includes 12 subframes, and each subframe includes 14464 symbols. The first type of subframe is shown in (b) of Fig. 8, which has 113 pilot symbols, 10 training symbols, 22 frame synchronization symbols, and 50 reserved symbols. In the existing 400G-ZR and 800G-ZR standards, the first subframe also contains 22 frame synchronization symbols, which is conducive to compatible implementation. The second type of subframe is shown in (c) of Fig. 8, which also has 113 pilot symbols and 10 training symbols. In each subframe, the first symbol in each continuous 128 symbols is a pilot symbol. In some specific applications, the bit width in the specific DSP implementation of the transceiver is 192 or 128, and the number of symbols N F of the superframe is an integer multiple of 192 and 128, which is conducive to hardware implementation.

[0201] In the embodiment, the 113 pilot symbols of each subframe adopt the symbol sequence as shown in Table 2. The N PS = 113 pilot symbols are generated by a generating polynomial and a seed. The generating polynomial is x 10 + x 7 + x 3 + x + 1, and the seeds in hexadecimal notation for the two polarization directions are 0x34E and 0x084. The N PS = 113 pilot symbols are the first 113 pilot symbols of the 114 pilot symbols of the existing 800ZR, that is, the last 1 pilot symbol is removed, which is beneficial to compatibility with the 800ZR and facilitates hardware implementation. FIG. 9 is a schematic diagram of autocorrelation characteristics and cross-correlation characteristics corresponding to the pilot symbol sequence in the embodiment of the application. As shown in FIG. 9, the horizontal coordinate represents offset (unit: symbol number), and the vertical coordinate represents normalized amplitude. The normalized amplitude of the sidelobe value of the periodic autocorrelation function of the sequence of the 113 pilot symbols in any polarization direction is not greater than 0.185, and the normalized amplitude of the periodic cross-correlation function value of the pilot symbols in different polarization directions is not greater than 0.195. The autocorrelation and cross-correlation characteristics are both good.

[0202] The 10 training symbols of each subframe adopt the symbol sequence of sequence number 1 in Table 4. FIG. 10 is a schematic diagram of autocorrelation characteristics and cross-correlation characteristics corresponding to the training symbol sequence in the embodiment of the application. As shown in FIG. 10, the horizontal coordinate represents offset (unit: symbol number), and the vertical coordinate represents normalized amplitude. The normalized amplitude of the non-periodic autocorrelation function sidelobe value of the sequence of the 10 training symbols in any polarization direction is not greater than 0.20, and the normalized amplitude of the non-periodic cross-correlation function value of the training symbols in different polarization directions is not greater than 0.37. The autocorrelation and cross-correlation characteristics are both good.

[0203] It is also to be noted that the first pilot symbol of the 113 pilot symbols is also a training symbol. The 10 training symbols and the 113 pilot symbols in each subframe combine together to be 10+113-1 = 122 symbols, which can also satisfy direct current balance, facilitate improvement of signal recovery at the receiving end, and improve the quality of the recovered signal.

[0204] FIG. 11 is a schematic diagram of a structure of a data transmission device in the embodiment of the application. The data transmission device is applied to a sending end. As shown in FIG. 11, the data transmission device includes a processing unit 201 and a sending unit 202. The processing unit 201 is configured to perform the operation of step 101 in the above embodiment, and the sending unit 202 is configured to perform the operation of step 102 in the above embodiment.

[0205] FIG. 12 is another structure of the data transmission apparatus in the embodiments of the present application. The data transmission apparatus is applied to a receiving end. As shown in FIG. 12, the data transmission apparatus includes a receiving unit 302, which is configured to perform the operation in step 102 in the embodiments. Optionally, the data transmission apparatus further includes a processing unit 301, which is configured to perform the operation in step 103 in the embodiments.

[0206] It should be understood that the data transmission apparatus provided in FIG. 11 and FIG. 12 can also be implemented in other manners. For example, the division of the units in the apparatus is only a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some units can be left out or combined into a unit. In addition, the various embodiments of the present application can be implemented in a form of a program instructing a computer device to perform the units. The program can be stored in a computer readable storage medium, for example, a computer storage medium or computer readable storage device, such as a ROM, a RAM, a magnetic disk, or an optical disk.

[0207] FIG. 13 is a structure of an optical module in the embodiments of the present application. As shown in FIG. 13, 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 configured to receive a signal from another apparatus and transmit the signal to the processor 401 or transmit a signal from the processor 401 to another apparatus. Optionally, the optical module can further include a memory 403, where the memory 403 is configured to store program instructions and data.

[0208] In a possible scenario, the optical module is applied to a sending end, and the processor 401 is configured to perform the operation in step 101 in the embodiments. For example, the processor 401 includes the processing unit 201 shown in FIG. 11. As an example, the processor 401 performs the operation in step 101 in the embodiments to obtain a data frame, and transmits the data frame through the interface 402. In this example, the interface 402 can be an electrical interface. As another example, the processor 401 performs the operation in step 101 in the embodiments to obtain a data frame, and a modulator in the optical module performs signal processing such as electrical-optical conversion on the data frame to obtain an optical signal, and then transmits the optical signal through the interface 402. In this example, the interface 402 can be an optical interface.

[0209] In another possible scenario, the optical module is applied to a receiving end, and the processor 401 is configured to perform the operation of step 103 in the above-described embodiments, for example, the processor 401 includes the processing unit 301 shown in FIG. 13. As an example, the interface receives an optical signal transmitted through a channel, a demodulator in the optical module performs photoelectric conversion and other signal processing on the optical signal to obtain a data frame, and the processor 401 performs the operation of step 103 in the above-described embodiments on the second data frame. In this example, the interface 402 can specifically refer to an optical interface. As another example, a demodulator in the optical module performs photoelectric conversion and other signal processing on the received optical signal to obtain a data frame, and transmits the second data frame to the processor 401 through the interface 402. The processor 401 performs the operation of step 103 in the above-described embodiments on the second data frame. In this example, the interface 402 can specifically refer to an electrical interface.

[0210] Generally, an optical module is composed of optoelectronic devices, a processor, an interface, and the like. The optoelectronic devices include a transmitting device and a receiving device. The transmitting end of the optical module converts an electrical signal into an optical signal and transmits the optical signal through an optical fiber. The receiving end of the optical module receives an optical signal and converts the optical signal into an electrical signal.

[0211] It should be noted that the types of the optical module in the embodiments of the present application include, but are not limited to, a normal optical module, a near package optics (NPO) module, a co-packaged optics (CPO) module, and the like. The functions that can be implemented by the normal optical module include, but are not limited to, digital signal processing (DSP) and clock data recovery (CDR), and the like. For example, the normal optical module converts an analog signal into a digital signal, performs DSP on the digital signal, and then converts the digital signal into an analog signal to be sent to a host-side device. Since retiming is required for DSP, the normal optical module can also be referred to as a retimed module. The normal optical module is connected to the host-side device through an attachment unit interface (AUI). The NPO module and the CPO module do not have a pluggable optical module physical package form, and are closer to the host-side device. The NPO module and the CPO module can also be referred to as an optical engine. The NPO technology or the CPO technology is a technology of “packaging” the host-side device (or the host-side chip) and the optical engine. When the host-side device and the optical engine are packaged by using the NPO technology, the optical engine can be referred to as an NPO module. When the host-side device and the optical engine are packaged by using the CPO technology, the optical engine can be referred to as a CPO module.

[0212] FIG. 14 is a schematic diagram of a structure of a network device in an embodiment of the present application. As shown in FIG. 14, the network device includes a host-side device 501 and an optical module 502. In a possible scenario, the network device serves as a sending end of data, the host-side device 501 is configured to send an electrical signal to the optical module 502, and the optical module 502 converts the electrical signal into an optical signal and sends the optical signal through a channel. In another possible scenario, the network device serves as a receiving end of data, the optical module 502 is configured to convert a received optical signal into an electrical signal and send the electrical signal to the host-side device 501. For example, the host-side device 501 can be a switch, a router, a server or the like. It should be understood that the network device in the embodiments of the present application has both the function of sending and the function of receiving.

[0213] An OTN device is also provided in an embodiment of the present application, and the OTN device includes a line side device and a client side device. In some scenarios, the client side device can also be referred to as a tributary side device. The line side device includes a processor and an interface. In a possible scenario, the OTN device is applied to a sending end, and the processor is configured to perform the operation of step 101 in the above embodiment. In another possible scenario, the OTN device is applied to a receiving end, and the processor is configured to perform the operation of step 103 in the above embodiment. The interface can be a transceiver or an input / output interface, and the interface is configured to receive a signal from another device outside the line side device and transmit the signal to the processor or send a signal from the processor to another device outside the line side device.

[0214] An embodiment of the present application also provides a chip. The chip integrates a circuit for implementing the function of the processor 401 and one or more interfaces. As an example, the chip integrates a memory. As another example, when the chip does not integrate a memory, the chip can be connected to an external memory through the interface. The chip can complete the method steps of any one or more of the above embodiments. Alternatively, the chip implements the actions performed by the transmission device in the above embodiments according to program codes stored in the memory.

[0215] As an example, the processor in the embodiments of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor, and can also be a processing circuit that implements specific functions.

[0216] The embodiments of the present application also provide a computer readable storage medium, including a program or instructions, when the program or instructions are executed on a computer, the program or instructions cause the computer to implement the method performed by the above method embodiments.

[0217] It should be understood that the processor mentioned in the embodiments of the present application can be implemented by hardware or software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc. When implemented by software, the processor can be a general-purpose processor, which is implemented by reading software codes stored in a memory. The memory can exist independently and be connected to the processor, or the memory can be integrated with the processor.

[0218] As an example, the processor in the embodiments of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor, and can also be a processing circuit that implements specific functions.

[0219] The memory of the embodiments of the present application can be random access memory (RAM), flash memory, read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically EPROM (EEPROM), register, hard disk, mobile hard disk, CD-ROM, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. Of course, the storage medium can be a component of the processor. The processor and the storage medium can be located in an ASIC. The ASIC can be located in a network device or terminal device. Of course, the processor and the storage medium can also exist as separate components in a network device or terminal device.

[0220] In the above embodiments, the implementation can be achieved wholly or partially by software, hardware, firmware, or any combination thereof.

[0221] When implemented by using hardware, the data transmission method provided by the embodiments of the present application can be implemented without reading software codes or instructions, for example, by using a CPU, DSP, ASIC, FPGA, other programmable logic device, transistor logic device, hardware component, or any combination thereof.

[0222] When implemented by using software, the implementation can be achieved wholly or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer programs or instructions are loaded and executed on a computer, the processes or functions of the embodiments of the present application are executed wholly or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a terminal device, or other programmable apparatus. The computer programs or instructions can be stored in a computer-readable storage medium or transmitted by a computer-readable storage medium. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server integrated with one or more available media. The available medium can be a magnetic medium, for example, a floppy disk, a hard disk, a magnetic tape; an optical medium, for example, a digital versatile disc (DVD); or a semiconductor medium, for example, a solid state disk (SSD).

[0223] Finally, it should be noted that the above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A data transmission method, characterized by, comprises: Transmitting a data frame comprising a plurality of sub-frames, wherein in one polarization direction, each of the plurality of sub-frames comprises an even number of training symbols, each of the plurality of sub-frames comprises one pilot symbol per N PG consecutive symbols, N PG is an integer greater than 1, each of the training symbols and each of the pilot symbols has a value of one of -A-Aj, -A+Aj, A-Aj and A+Aj, A is a real number, j represents an imaginary unit, one symbol in each of the plurality of sub-frames is both a training symbol and a pilot symbol, and the number of pilot symbols in each of the plurality of sub-frames is 113.

2. The method of claim 1, wherein, In one polarization direction, the number of the training symbols in each of the plurality of subframes is 8, 10 or 12.

3. The method according to claim 1 or 2, characterized in that, The 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generator polynomial and a seed, the generator polynomial being x 10 + x 7 + x 3 + x + 1; the seed being Ox34E in a first polarization direction and Ox084 in a second polarization direction.

4. The method according to any one of claims 1 to 3, characterized in that, In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A+Aj, A-Aj, A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, respectively. In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, A-Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, A-Aj.

5. The method according to claim 3 or 4, characterized in that, In the first polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj; in the second polarization direction, the sum of the values of all the training symbols in each of the plurality of subframes is -2A.

6. The method according to any one of claims 3 to 5, characterized in that, In one polarization direction, the number of the training symbols in each of the plurality of subframes is 8, and the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following tables:

7. The method according to any one of claims 3 to 5, characterized in that, In one polarization direction, the number of the training symbols in each of the plurality of subframes is 10, and the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following tables:

8. The method according to any one of claims 3 to 5, characterized in that, In one polarization direction, the number of the training symbols in each of the plurality of subframes is 12, and the values of the 12 training symbols in each of the plurality of subframes in the first polarization direction and the values of the 12 training symbols in each of the plurality of subframes in the second polarization direction satisfy one of the following tables:

9. The method of claim 1 or 2, wherein, In one polarization direction, the 113 pilot symbols in each of the plurality of subframes are a complex sequence generated by a generator polynomial and a seed, the generator polynomial being x 10 + x 8 + x 4 + x 3 + 1; the seed being Ox19E in the first polarization direction and Ox0D0 in the second polarization direction.

10. The method of claim 1, 2, or 9, wherein, In the first polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A+Aj, A+Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A+Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A-Aj, -A-Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A+Aj, A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, A+Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, -A+Aj, A+Aj, A-Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A+Aj, -A-Aj, -A-Aj, A+Aj, A-Aj, A+Aj, -A+Aj, -A-Aj, -A+Aj, -A-Aj, -A+Aj, -A+Aj; In the second polarization direction, the values of the 113 pilot symbols in each of the plurality of subframes are -A-Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A+Aj, A+Aj, -A-Aj, A+Aj, A+Aj, A-Aj, A+Aj, A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A-Aj, A-Aj, A+Aj, -A+Aj, A+Aj, A+Aj, A-Aj, -A+Aj, -A-Aj, A-Aj, -A-Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, A-Aj, A-Aj, -A-Aj, -A-Aj, A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, -A+Aj, -A-Aj, A-Aj, A-Aj, -A+Aj, A+Aj, -A-Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, -A+Aj, -A-Aj, -A+Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A-Aj, -A-Aj, A-Aj, -A+Aj, -A+Aj, A-Aj, A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, A-Aj, -A+Aj, A-Aj, -A-Aj, A+Aj, -A-Aj, -A+Aj, -A+Aj, A+Aj, -A+Aj, A-Aj, A+Aj, -A+Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, -A+Aj.

11. The method according to claim 9 or 10, characterized in that, The sum of the values of all the training symbols in each of the plurality of subframes is 2A+2Aj in the first polarization direction; and the sum of the values of all the training symbols in the subframe is 2A-2Aj in the second polarization direction.

12. The method according to any one of claims 9 to 11, characterized in that, In one polarization direction, the number of the training symbols in each of the plurality of subframes is 8, and the values of the 8 training symbols in the first polarization direction and the values of the 8 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following tables:

13. The method according to any one of claims 9 to 11, characterized in that, In one polarization direction, the number of the training symbols in each of the plurality of subframes is 10, and the values of the 10 training symbols in the first polarization direction and the values of the 10 training symbols in the second polarization direction in each of the plurality of subframes satisfy one of the following tables:

14. The method according to any one of claims 9 to 11, characterized in that, In one polarization direction, the number of the training symbols in each of the plurality of subframes is 12, and the values of the 12 training symbols in each of the plurality of subframes in the first polarization direction and the values of the 12 training symbols in each of the plurality of subframes in the second polarization direction satisfy one of the following tables:

15. The method according to any one of claims 1 to 14, characterized in that, N PG ＝128。 16. The method according to any one of claims 1 to 15, characterized in that, The data frame adopts a symbol mapping mode of quadrature phase shift keying (QPSK), and A=-1 or 1; or the data frame adopts a symbol mapping mode of 16-quadrature amplitude modulation (16QAM), and A=-3 or 3.

17. The method of any one of claims 1 to 16, wherein, In one polarization direction, the subframe includes N TS training symbols, the sum of all training symbols and all pilot symbols in the subframe is 113+N TS -1 symbols.

18. The method of any one of claims 1 to 17, wherein, In one polarization direction, the subframe includes N TS training symbols, and a total of 113+N TS -1 symbols including all training symbols and all pilot symbols in the subframe satisfy direct current balance.

19. The method of any one of claims 1 to 18, wherein, The subframe arranged at the first position in the data frame is a first type of subframe, the first type of subframe further includes a frame synchronization symbol, a reserved symbol and a pre-formation symbol, and in the first type of subframe, the training symbol is located before the frame synchronization symbol, the frame synchronization symbol is located before the reserved symbol, and the reserved symbol is located before the pre-formation symbol. The data frame includes at least one second type of subframe, and the second type of subframe further includes a pre-formation symbol, and in the second type of subframe, the training symbol is located before the pre-formation symbol.

20. A data transmission method, characterized by, The method comprises the following steps: A second data frame including a plurality of subframes is received through a channel, wherein each of the plurality of subframes includes an even number of training symbols in one polarization direction, each of the plurality of subframes includes one pilot symbol per N PG consecutive symbols, N PG is an integer greater than 1, each of the training symbols and each of the pilot symbols has one of values -A-Aj, -A+Aj, A-Aj and A+Aj, A is a real number, j represents an imaginary unit, one symbol in each of the plurality of subframes is both a training symbol and a pilot symbol, and the number of the pilot symbols in each of the plurality of subframes is 113.

21. A data transmission device, characterized by The method comprises the following steps: The sending unit is configured to send a data frame comprising a plurality of sub-frames, wherein in one polarization direction, each of the plurality of sub-frames comprises an even number of training symbols, each of the plurality of sub-frames comprises one pilot symbol per N PG consecutive symbols, N PG is an integer greater than 1, each of the training symbols and each of the pilot symbols has a value of one of -A-Aj, -A+Aj, A-Aj and A+Aj, A is a real number, j represents an imaginary unit, each of the plurality of sub-frames has one symbol that is both a training symbol and a pilot symbol, and the number of the pilot symbols in each of the plurality of sub-frames is 113.

22. A data transmission apparatus, characterized by comprising: The method comprises the following steps: The receiving unit is configured to receive a second data frame including a plurality of sub-frames transmitted through a channel, wherein each of the plurality of sub-frames includes an even number of training symbols in one polarization direction, each of the plurality of sub-frames includes one pilot symbol per N PG consecutive symbols, N PG is an integer greater than 1, each of the training symbols and each of the pilot symbols has a value of one of -A-Aj, -A+Aj, A-Aj and A+Aj, A is a real number, j represents an imaginary unit, each of the plurality of sub-frames has one symbol that is both a training symbol and a pilot symbol, and each of the plurality of sub-frames has a number of pilot symbols of 113.

23. A chip, characterized by The chip is used for executing the method as claimed in any one of claims 1 to 20.

24. An optical module characterized by comprising: The optical module comprises a processor and an interface, the interface is used for transceiving signals, and the processor is used for executing the method as claimed in any one of claims 1 to 20.

25. A network device, comprising: The network device comprises a host-side device and the optical module as claimed in claim 24; the optical module is used for converting an electrical signal from the host-side device into an optical signal and transmitting the optical signal, or the optical module is used for converting a received optical signal into an electrical signal and transmitting the electrical signal to the host-side device.

26. A communication system, characterized by The network device comprises a plurality of optical modules as claimed in claim 25, and the plurality of optical modules are used for transmitting optical signals to each other.

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