Data transmission method, apparatus and system

Abstract

Disclosed in the embodiments of the present application are a data transmission method, an apparatus and a system. The method comprises: acquiring a data frame comprising a plurality of subframes, wherein, in one polarization direction, each subframe comprises 226 pilot symbols, the 226 pilot symbols are generated by a target polynomial and a seed, and the target polynomial is x^11+x^10+x^9+x^7+1; and sending the data frame. The frame redundancy of the superframe architecture provided by the present embodiment is low, and the sequence autocorrelation and cross-correlation properties of the pilot symbols are good, thus facilitating recovery of signals by receiving ends, and improving the quality of recovered signals.

Description

A data transmission method, apparatus and system

[0001] This application claims priority to Chinese Patent Application No. 202411065397.2, filed on August 2, 2024, entitled "A Data Transmission Method, Apparatus and System", the entire contents of which are incorporated herein by reference. Technical Field

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

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

[0004] Existing transmission symbol sequences are mainly used in 400Gbps or 800Gbps scenarios, which cannot adapt to future scenarios above 800Gbps (including 1.2Tbps, 1.6Tbps, etc.), and the transmission redundancy is relatively large. Summary of the Invention

[0005] This application provides a data transmission method, apparatus, and system with low transmission redundancy and good correlation of the added preset symbol sequence, which is beneficial to improving the quality of the recovered signal at the receiving end and can be well applied to various coherent transmission scenarios.

[0006] In a first aspect, embodiments of this application provide a data transmission method, the method comprising: acquiring a data frame comprising multiple subframes, wherein in one polarization direction, the subframe comprises 226 pilot symbols, the 226 pilot symbols being generated by a target polynomial and a seed, wherein the target polynomial is x^11+x^10+x^9+x^7+1; and transmitting the data frame.

[0007] In some possible implementations, the seed for the X-polarization direction is 0x5B2, and the seed for the Y-polarization direction is 0x6B4.

[0008] In this embodiment, the normalized amplitudes of the sidelobe values ​​of the periodic autocorrelation function of the pilot symbol sequences in both polarization directions and the normalized amplitudes of the sidelobe values ​​of the periodic cross-correlation function of the pilot symbol sequences in both polarization directions are both no greater than 0.15. The superframe architecture provided in this embodiment also has low frame redundancy, and the sequence autocorrelation and cross-correlation characteristics of the pilot symbols are good. The combination of training symbols and pilot symbols can also satisfy DC balance, which is beneficial to improving the signal recovered at the receiver and improving the quality of the recovered signal.

[0009] It should be understood that the 226 pilot symbols may also correspond to the generator polynomials (also known as target polynomials) given in Table 2 or Table 3, and this application does not limit this; in addition, the subframe may also include 113 pilot symbols, the corresponding target polynomials and seeds of which are specifically described in the embodiments (e.g., Table 7), and will not be repeated here.

[0010] In some possible implementations, the subframe also includes 11 training symbols in one polarization direction.

[0011] In some possible implementations, the sequence of training symbols is respectively located in the X and Y polarization directions as follows:

[0012] In some possible implementations, the subframe includes 28,928 symbols in one polarization direction.

[0013] In some possible implementations, the 226 pilot symbols are respectively located in the X and Y polarization directions as follows:

[0014] Secondly, embodiments of this application provide a data transmission method, including: receiving a second data frame transmitted through a channel from a first data frame, wherein the first data frame includes multiple subframes, and in one polarization direction, the subframes include 226 pilot symbols, wherein the 226 pilot symbols are generated by a target polynomial and a seed, wherein the target polynomial is x^11+x^10+x^9+x^7+1.

[0015] In some possible implementations, the seed for the X-polarization direction is 0x5B2, and the seed for the Y-polarization direction is 0x6B4.

[0016] In this embodiment, a receiver scheme corresponding to the first aspect is provided, which can ensure that the normalized amplitude of the sidelobe values ​​of the periodic autocorrelation function of the pilot symbol sequences in both polarization directions and the normalized amplitude of the sidelobe values ​​of the periodic cross-correlation function of the pilot symbol sequences in both polarization directions are not greater than 0.15. The superframe architecture provided in this embodiment also has low frame redundancy, and the sequence autocorrelation and cross-correlation characteristics of the pilot symbols are good. The combination of training symbols and pilot symbols can also satisfy DC balance, which is beneficial to improving the signal recovered by the receiver and improving the quality of the recovered signal.

[0017] It should be understood that the 226 pilot symbols may also correspond to the generator polynomials (also known as target polynomials) given in Table 2 or Table 3, and this application does not limit this; in addition, the subframe may also include 113 pilot symbols, the corresponding target polynomials and seeds of which are specifically described in the embodiments (e.g., Table 7), and will not be repeated here.

[0018] In some possible implementations, the subframe also includes 11 training symbols in one polarization direction.

[0019] In some possible implementations, the sequence of training symbols is respectively located in the X and Y polarization directions as follows:

[0020] In some possible implementations, the subframe includes 28,928 symbols in one polarization direction.

[0021] In some possible implementations, the 226 pilot symbols are respectively located in the X and Y polarization directions as follows:

[0022] Thirdly, embodiments of this application provide a data transmission apparatus, including: a processing unit and a sending unit;

[0023] The processing unit is configured to: acquire a data frame comprising multiple subframes, wherein, in one polarization direction, the subframe data frame comprises 226 pilot symbols, the 226 pilot symbols being generated by a target polynomial and a seed, wherein the target polynomial is x^11+x^10+x^9+x^7+1; the transmitting unit is configured to: transmit the data frame.

[0024] The third aspect is a data transmission device corresponding to the first aspect. For specific implementation details, please refer to some possible implementations of the first aspect, which will not be repeated here.

[0025] Fourthly, embodiments of this application provide a data transmission apparatus, including: a receiving unit; the receiving unit is configured to: receive a second data frame transmitted through a channel from a first data frame, the first data frame including multiple subframes, and in one polarization direction, the subframe including 226 pilot symbols, the 226 pilot symbols being generated by a target polynomial and a seed, wherein the target polynomial is x^11+x^10+x^9+x^7+1.

[0026] The fourth aspect is a data transmission device corresponding to the second aspect. For specific implementation details, please refer to some possible implementations of the second aspect, which will not be repeated here.

[0027] Fifthly, embodiments of this application provide a chip for performing the methods described in any of the first or second aspects.

[0028] Sixthly, embodiments of this application provide an optical module, which includes a processor and an interface. The interface is used to transmit and receive signals, and the processor is used to execute the methods described in any embodiment of the first aspect. For example, the interface is used to transmit signals from the processor or to transmit received signals to the processor.

[0029] In a seventh aspect, embodiments of this application provide a transmitting device. The transmitting device includes a host-side device and an optical module as described in the sixth aspect, the optical module being used to convert electrical signals from the host-side device into optical signals and to transmit the optical signals.

[0030] Eighthly, embodiments of this application provide an optical module including a processor and an interface. The interface is used to transmit and receive signals, and the processor is used to execute the methods described in any embodiment of the second aspect. For example, the interface is used to transmit signals from the processor or to transmit received signals to the processor.

[0031] Ninthly, embodiments of this application provide a receiving device. The receiving device includes a host-side device and an optical module as described in the eighth aspect, the optical module being used to convert a received optical signal into an electrical signal and transmit the electrical signal to the host-side device.

[0032] In a tenth aspect, embodiments of this application provide a communication system including a transmitting device as described in the seventh aspect and a receiving device as described in the ninth aspect, wherein the transmitting device is used to transmit an optical signal to the receiving device.

[0033] In one aspect, this application provides a computer-readable storage medium storing instructions that, when executed by a computer, cause the method described in any of the embodiments of the first or second aspect to be implemented.

[0034] In a twelfth aspect, this application provides a computer program product including program instructions that, when executed, implement the method described in any of the embodiments of the first or second aspect above. Attached Figure Description

[0035] Figure 1 is a schematic diagram of a communication system applied in an embodiment of this application;

[0036] Figure 2(a) is a schematic diagram of one implementation of the starting DSP processor in an embodiment of this application;

[0037] Figure 2(b) is a schematic diagram of another implementation of the DSP processor in this application;

[0038] Figure 2(c) is a schematic diagram of another embodiment of the DSP processor in this application;

[0039] Figure 2(d) is a schematic diagram of another embodiment of the DSP processor in this application.

[0040] Figure 3 is a schematic diagram of a data transmission method in an embodiment of this application;

[0041] Figure 4 is a schematic diagram of the structure of a data frame in an embodiment of this application;

[0042] Figure 5 is a schematic diagram of a subframe structure in a data frame according to an embodiment of this application;

[0043] Figure 6 is a schematic diagram of a constellation diagram in an embodiment of this application;

[0044] Figure 7(a) is a schematic diagram of the first pilot symbol generation structure in the embodiments of this application;

[0045] Figure 7(b) is a schematic diagram of the second pilot symbol generation structure in the embodiments of this application;

[0046] Figure 7(c) is a schematic diagram of the third pilot symbol generation structure in the embodiments of this application;

[0047] Figure 8 is a schematic diagram of a specific target symbol generation structure provided in an embodiment of this application;

[0048] Figure 9 is a schematic diagram of another specific target symbol generation structure provided in the embodiments of this application;

[0049] Figure 10 is a schematic diagram of another specific target symbol generation structure provided in the embodiments of this application;

[0050] Figure 11 is a schematic diagram of a data transmission device in an embodiment of this application;

[0051] Figure 12 is a schematic diagram of another structure of the data transmission device in an embodiment of this application;

[0052] Figure 13 is a schematic diagram of an optical module in an embodiment of this application;

[0053] Figure 14 is a schematic diagram of a transmitting device in an embodiment of this application;

[0054] Figure 15 is a schematic diagram of a receiving device in an embodiment of this application. Detailed Implementation

[0055] This application provides a data transmission method, apparatus, and system with low transmission redundancy and good correlation of the added preset symbol sequence, which is beneficial to improving the quality of the recovered signal at the receiving end and can be well applied to various coherent transmission scenarios.

[0056] It should be noted that the terms "first," "second," etc., in this application specification, claims, and the accompanying drawings are used to distinguish similar objects, not to limit a specific order or sequence. It should be understood that the above terms can be used interchangeably where appropriate so that the embodiments described in this application can be implemented in a sequence other than that described in this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0057] Figure 1 is a schematic diagram of a communication system applied in an embodiment of this application. As shown in Figure 1, at the transmitting end, the source provides a data stream to be transmitted. A forward error correction (FEC) encoder receives the data stream and performs FEC encoding on it. The codeword information obtained by combining the parity bits and information bits is sent to the transmitting end digital signal processing (DSP) processor for framing, and then transmitted through the channel to the receiving end. After receiving the distorted signal caused by noise or other impairments in the channel, the receiving end sends it to the receiving end DSP processor for dispersion compensation, synchronization, phase recovery, and other operations. Then, it is decoded by the FEC decoder to recover the original data and send it to the destination. The above-mentioned framing can also be called DSP framing.

[0058] Figure 2(a) is a schematic diagram of one implementation of the transmitting DSP processor in an embodiment of this application. As shown in Figure 2(a), in one possible implementation, the transmitting DSP processor performs dual-polarization symbol mapping on the received data sequence. Typically, the received data sequence is information and a check sequence obtained through FEC encoding. Dual-polarization symbol mapping includes symbol mapping and polarization distribution. The symbol mapping method is quadrature amplitude modulation (QAM). Typically, QAM modulation (also known as symbol mapping) involves symbol mapping multiple input bits to obtain multiple QAM symbols, and polarization distribution of the multiple QAM symbols to obtain multiple dual-polarization (DP) symbols, i.e., DP-QAM symbols, such as DP-4QAM (also known as dual-polarization quadrature phase shift keying, DP-QPSK), DP-16QAM, DP-32QAM, and DP-64QAM, etc. It should be understood that the symbol mapping usually uses gray mapping, mapping multiple bits to one QAM symbol, and in this case, the symbol mapping is also simply called gray mapping. For ease of explanation, the two polarization directions will be uniformly referred to as the X-polarization direction and the Y-polarization direction, respectively, where the X-polarization direction and the Y-polarization direction are orthogonal to each other. It should be understood that the X-polarization direction and the Y-polarization direction are not two specified polarization directions, but rather any two mutually orthogonal polarization directions. Furthermore, the transmitting DSP processor performs framing processing on a certain number of dual-polarization symbols as follows: specifically, it acquires a pre-framing dual-polarization symbol sequence containing multiple dual-polarization symbols; inserts a frame alignment word sequence (FAW Sequence) and a training symbol sequence into the X-polarization direction and the Y-polarization direction, respectively; and retains at least one of the reserved symbol sequence and the pilot symbol sequence, resulting in a post-framing dual-polarization symbol sequence. The inserted symbol sequence can also be called a preset symbol sequence.

[0059] In this embodiment, the pre-framing dual-polarization symbol is also called the payload symbol, which includes FEC-encoded information and parity bits, and the resulting symbol (called the information symbol and parity symbol) is obtained through symbol mapping. The post-framing dual-polarization symbol sequence is called a data frame, or a frame or DSP frame. For ease of introduction, this application embodiment uniformly refers to the post-framing dual-polarization symbol sequence as a data frame. Frame synchronization symbols are used for frame synchronization alignment, training symbols are used for link training, pilot symbols are used for carrier phase recovery, and reserved symbols are used for future use and innovation. The values ​​of reserved symbols can be known and unchanging, or they can be randomized; the values ​​of reserved symbols can also be called patterns. In some specific embodiments, the DSP frame contains multiple subframes, and the DSP frame is called a super-frame. In other specific embodiments, the DSP frame can also be called a multi-frame, the reserved symbols can also be called fixed stuff (FS), and the frame synchronization symbol can also be called a multi-frame alignment signal (MFAS).

[0060] It should be noted that the inserted symbol sequences are not exactly the same in the X-polarization and Y-polarization directions. That is, at at least one position, the values ​​of the symbols inserted in the X-polarization and Y-polarization directions are different. This avoids the problem of the receiver being unable to distinguish between the two polarization directions during actual transmission. For example, if 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, then the sequence of 8 training symbols in the Y-polarization direction cannot be exactly the same; it can be -A+Aj, -A-Aj, A-Aj, A+Aj, -A-Aj, -A+Aj, A-Aj, A+Aj.

[0061] It should be understood that a dual-polarization symbol can be represented by two symbols, one located in the X-polarization direction and the other in the Y-polarization direction. Each symbol can be represented by a complex number. For example, a symbol obtained using 16QAM modulation can be represented by any one of the following 16 complex numbers: ±1±1j, ±1±3j, ±3±1j, and ±3±3j, where ± indicates a positive or negative value, such as ±3 representing 3 or -3. Here, j represents the imaginary unit. For another example, a symbol obtained using QPSK modulation can be represented by any one of the following four complex numbers: ±1±1j. In some scenarios, the imaginary unit may also be represented by other symbols such as i, which is not limited here. In the embodiments of this application, the imaginary unit is uniformly represented by j. In some specific applications, the real and imaginary parts may be normalized, but the essence remains unchanged.

[0062] It should be noted that a sequence with N0 dual-polarization symbols can be completely represented by two complex sequences of length N0, one representing the symbol in the X-polarization direction and the other representing the symbol in the Y-polarization direction. Each complex sequence of length N0 is represented by a sequence of N0 real parts (also called the I-path sequence) and a sequence of N0 imaginary parts (also called the Q-path sequence), where N0 is an integer greater than 1. Therefore, there are four different types of sequences, including the X-polarization I-path (in-phase component) sequence, the X-polarization Q-path (quadrature-phase component) sequence, the Y-polarization I-path sequence, and the Y-polarization Q-path sequence. The X-polarization I-path sequence is also called the X... I The component, the Q-path sequence in the X polarization direction, is also called X. Q The component, the Y-polarization direction I-path sequence, is also called the Y component. I The component, the Q-path sequence in the Y-polarization direction, is also called the Y-axis. Q Quantity.

[0063] It should be noted that after dual-polarization symbol mapping and framing operations, a dual-polarization symbol data stream to be transmitted is obtained. This stream can be represented by two symbol data streams: the first is the symbol data stream in the X-polarization direction, and the second is the symbol data stream in the Y-polarization direction. Alternatively, a dual-polarization symbol data stream can also be represented by four data streams, where the first is the data stream corresponding to the I-path component in the X-polarization direction (referred to as X...). I The second data stream is the data stream of the Q-path component in the X-polarization direction corresponding to the dual-polarization symbol stream (abbreviated as X). Q The third data stream is the data stream of the I-path component in the Y-polarization direction corresponding to the dual-polarization symbol stream (abbreviated as Y). IThe fourth data stream is the data stream of the Q-path component in the Y-polarization direction corresponding to the dual-polarization symbol stream (abbreviated as Y). Q (Data flow).

[0064] It should be understood that in the dual-polarization symbol mapping and framing operation shown in Figure 2(a), framing (also known as DSP framing) is performed after dual-polarization symbol mapping, that is, framing is performed on the symbol level. Below are schematic diagrams of several other possible implementations of the originating DSP processor, where framing is performed before dual-polarization symbol mapping, that is, framing is performed on the bit level.

[0065] Figure 2(b) is a schematic diagram of another implementation of the transmitting DSP processor in this application. As shown in Figure 2(b), framing is performed before dual-polarization symbol mapping. Specifically, a pre-framing bit sequence containing multiple bits is obtained, a 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 then processed by dual-polarization symbol mapping to obtain a preset symbol sequence, which is also referred to as the bits corresponding to the preset symbol sequence. It should be understood that the post-framing dual-polarization symbol sequence obtained by using the implementation shown in Figure 2(b) is the same as the post-framing dual-polarization symbol sequence obtained by using the implementation shown in Figure 2(a).

[0066] Figure 2(c) is a schematic diagram of another embodiment of the transmitting DSP processor in this application. As shown in Figure 2(c), framing is performed before dual-polarization symbol mapping. Specifically, two pre-framing bit sequences containing multiple bits are obtained respectively. A first preset bit sequence and a second preset bit sequence are inserted into the first and second pre-framing bit sequences respectively, and dual-polarization symbol mapping is performed to obtain a post-framing dual-polarization symbol sequence. The first preset bit sequence is symbol mapped to obtain a preset symbol sequence in the X-polarization direction, and the second preset bit sequence is symbol mapped to obtain a preset symbol sequence in the Y-polarization direction. The first preset bit sequence is also called the bit corresponding to the preset symbol sequence in the X-polarization direction, and the second preset bit sequence is also called 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 the pre-framing bit sequence using the embodiment shown in Figure 2(c) is the same as the post-framing dual-polarization symbol sequence obtained by the embodiment shown in Figure 2(a).

[0067] Figure 2(d) is a schematic diagram of another embodiment of the originating DSP processor in this application. As shown in Figure 2(d), framing is performed before dual-polarization symbol mapping. Specifically, four pre-framing bit sequences containing multiple bits are obtained respectively. A first preset bit sequence, a second preset bit sequence, a third preset bit sequence, and a fourth preset bit sequence are inserted into the first, second, third, and fourth pre-framing bit sequences, respectively, and dual-polarization symbol mapping is performed to obtain the post-framing dual-polarization symbol sequence. The first preset bit sequence is symbol mapped to obtain the I-path component of the preset symbol sequence in the X-polarization direction; the second preset bit sequence is symbol mapped to obtain the Q-path component of the preset symbol sequence in the X-polarization direction; the third preset bit sequence is symbol mapped to obtain the I-path component of the preset symbol sequence in the Y-polarization direction; and the fourth preset bit sequence is symbol mapped to obtain the Q-path component of the preset symbol sequence in the Y-polarization direction. The first preset bit sequence is also called the preset symbol sequence in the X-polarization direction. I The bits corresponding to the components, the second preset bit sequence, also known as the preset symbol sequence, are in X. Q The bits corresponding to the components, the third preset bit sequence, also known as the preset symbol sequence, are in Y. I The bits corresponding to the components, the fourth preset bit sequence, also known as the preset symbol sequence, are in Y. Q The bits corresponding to the components. It should be understood that the framed dual-polarization symbol sequence obtained by using the implementation shown in Figure 2(d) before framing is the same as the framed dual-polarization symbol sequence obtained by using the implementation shown in Figure 2(a).

[0068] It should be noted that this application does not limit the specific framing method adopted by the sending DSP processor. In addition to the framing methods described in Figures 2(a), 2(b), 2(c), and 2(d), other similar framing methods are also applicable to this scheme, and will not be described in detail here.

[0069] In some specific applications, the subframe arranged first in the data frame is a first-type subframe. This first-type subframe includes pre-framing symbols, training symbols, pilot symbols, frame synchronization symbols, and reserved symbols. Typically, in this first-type subframe, the training symbols precede the frame synchronization symbols, the frame synchronization symbols precede the reserved symbols, and the reserved symbols precede the pre-framing symbols. The data frame includes at least one second-type subframe. This second-type subframe includes pre-framing symbols, training symbols, and pilot symbols. Typically, in this second-type subframe, the training symbols precede the pre-framing symbols.

[0070] Figure 3 is a schematic diagram of a data transmission method according to an embodiment of this application. As shown in Figure 3, the data transmission method includes the following steps.

[0071] 101. The sending end obtains the data frame.

[0072] It should be noted that this application does not limit the specific implementation method of generating data frames. For example, the dual-polarization symbol mapping and framing method described in Figures 2(a), 2(b), 2(c), or 2(d) can be used. Of course, other similar dual-polarization symbol mapping and framing methods are also applicable to this scheme, and will not be described in detail here. It should be understood that a data frame includes symbols in two polarization directions. The structure of the data frame is similar in both polarization directions. For example, a data frame includes a symbol sequence in the X polarization direction and a symbol sequence in the Y polarization direction. The structure of the data frame will be described below using one polarization direction as an example.

[0073] Figure 4 is a schematic diagram of a data frame structure in an embodiment of this application. As shown in Figure 4, the data frame contains N SF There are N subframes, each containing N S Each subframe contains T training symbols and M pilot symbols, N symbols. SF N S T and M are all integers greater than 0. The training symbol sequence consisting of T training symbols is also simply called the training sequence. The pilot symbol sequence consisting of M pilot symbols is also simply called the pilot sequence. The subframes mainly include two types: one type of subframe includes frame synchronization symbols, which is usually the first subframe, and the other subframes are the second type of subframes.

[0074] Figure 5 is a schematic diagram of a subframe structure in a data frame according to an embodiment of this application. As shown in example (a) of Figure 5, the first type of subframe contains T training symbols and M pilot symbols, one of which is both a training symbol and a pilot symbol. Here, T and M are integers greater than 0. The first T symbols in the first type of subframe are training symbols, which can be used for link training and subframe synchronization. Typically, the first symbol of the subframe (the symbol at the starting position) is both a training symbol and a pilot symbol. Of course, it is also possible that any one of the first T symbols is both a training symbol and a pilot symbol; this application does not limit this. Furthermore, in the first type of subframe, every N g The symbols at fixed positions within the symbol set are pilot symbols used for carrier phase recovery. For example, the example in Figure 5(a) shows a set of symbols for each N... g The first symbol in the set of symbols is the pilot symbol. In some specific applications, the integer N... g The values ​​are 32, 64, 96, or 128. After T training symbols, N is the number of symbols. FAW A frame synchronization symbol is used for synchronization between superframes (also known as multiple frames). Furthermore, in N... FAW After each frame synchronization symbol, there is usually N. RESThe reserved symbols can be set aside for future uses, and can also be located within one of multiple second-type subframes; this application does not impose any limitations on either. Wherein, N g N FAW and N RES All are integers greater than 0.

[0075] As shown in example (b) of Figure 5, the second type of subframe contains T training symbols and M pilot symbols, where one symbol is both a training symbol and a pilot symbol. In the second type of subframe, the first T symbols are training symbols, and every N... g The symbol at a fixed position among the symbols is the pilot symbol. Typically, in the second type of subframe, apart from the training symbols and pilot symbols, the remaining symbols are pre-frame (payload) symbols.

[0076] It should be understood that, in the data frame structure shown in Figure 5, the total number of symbols in each subframe, consisting of T training symbols and M pilot symbols in one polarization direction, is not T+M. It needs to be considered that the first symbol is both a pilot symbol and a training symbol, so the total number of symbols needs to be reduced by 1. That is, the total number of symbols in each subframe, consisting of T training symbols and M pilot symbols, is N. TP = T+M-1 symbols. Each training symbol and each pilot symbol takes the value of one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a non-zero real number and j represents the imaginary unit. Here, Aj can also be written as A×j. It should be noted that the data frame contains N... SF There are N subframes, containing a total of N SF ×T training symbols and N SF ×M pilot symbols. The N SF ×T training symbols and N SF ×M pilot symbols combined into a total of N SF ×N TP The symbols satisfy direct current balance. That is, the N symbols... SF ×N TP The sum of the symbols is 0. More specifically, in one polarization direction, the N SF ×N TP The sum of the real parts of the complex numbers corresponding to each symbol is 0, and the sum of the imaginary parts is also 0, which can achieve DC balance and help improve the quality of the signal recovered by the receiver.

[0077] In some specific applications, 16QAM symbol mapping is used, and the 16 constellation points (also called symbols) on the corresponding 16QAM constellation diagram take values ​​of {±1±1j,±1±3j,±3±1j,±3±3j}. As shown in the example of Figure 6(a), hollow circles are used to represent the four outermost constellation points in the constellation diagram, namely the symbols -3-3j, -3+3j, 3-3j, and 3+3j, and vertical circle is used to represent the four innermost constellation points in the constellation diagram, namely the symbols -1-1j, -1+1j, 1-1j, and 1+1j. Example 6(b) illustrates a specific symbol mapping method for 16QAM. A 16QAM symbol in the X-polarization direction or the Y-polarization direction is obtained by mapping 4 bits. For example, 0000 is mapped to -3-3j, 0101 is mapped to -1-1j, 0010 is mapped to -3+3j, 0111 is mapped to -1+1j, 1010 is mapped to 3+3j, 1111 is mapped to 1+1j, 1000 is mapped to 3-3j, and 1101 is mapped to 1-1j.

[0078] Typically, for the 16QAM symbol mapping described above, A = 3 or -3 is selected to ensure good sensitivity of the training symbols or pilot symbols. For QPSK symbol mapping, the four constellation points (also called symbols) on the constellation diagram are set to {±1±1j}, and A = 1 or -1 is selected.

[0079] 102. The sending end sends a data frame to the receiving end.

[0080] The data frames sent by the transmitting end will be transmitted to the receiving end through the channel. In some possible scenarios, the dual-polarization symbols in the data frame will be converted from digital to analog (DAC) to obtain four analog signals, corresponding to the I component signal in the X-polarization direction, the Q component signal in the X-polarization direction, the I component signal in the Y-polarization direction, and the Q component signal in the Y-polarization direction, respectively, and then transmitted to the receiving end through optical fiber.

[0081] 103. The receiving end performs signal processing on the received data frames.

[0082] It should be understood that the data frame received by the receiving end is a data frame transmitted through the channel, which can be understood as a distorted signal affected by noise or other impairments in the channel. That is, the data frame received by the receiving end is different from the data frame sent by the 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 based on frame synchronization symbols or training symbols. The specific operations performed by the receiving end after receiving the data frame will not be described in detail in this application. For details, please refer to the system structure diagram shown in Figure 1. For example, the receiving end DSP processor performs signal processing on the received data frame, including operations such as dispersion compensation, synchronization, and phase recovery.

[0083] It should be noted that in some specific applications, for the sake of hardware simplicity, at least one subframe of the data frame contains M pilot symbols generated by a target polynomial and a seed. Several possible methods for generating the M pilot symbols are described below.

[0084] Typically, the M pilot symbols in the X-polarization direction are generated by the target polynomial and the seed in the X-polarization direction; the M pilot symbols in the Y-polarization direction are generated by the target polynomial and the seed in the Y-polarization direction. In this embodiment, the same generating polynomial (also called the target polynomial) can be used for pilot symbols in two orthogonal polarization directions. However, since the seeds used in the two polarization directions are different, the M pilot symbols obtained in the two polarization directions are not exactly the same.

[0085] Figure 7(a) is a schematic diagram of the first pilot symbol generation structure in the embodiment of this application. The target polynomial is a 10th-order polynomial, which can be expressed as: x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1. Where a9…a1 can take the values ​​0 or 1.

[0086] It should be noted that an algebraic expression composed of the addition (or subtraction) of several monomials is called a polynomial. Each monomial in a polynomial is called a term of the polynomial, and the degree of the highest term among these monomials is the degree of the polynomial. The number of terms in a polynomial refers to the number of the monomials with non-zero coefficients; for example, the number of terms in the 10th-order polynomial mentioned above is equal to the number of non-zero terms in a9…a1 plus 2.

[0087] In some specific applications, the number of non-zero terms in a9…a1 is no greater than 6, meaning the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8, resulting in lower hardware implementation complexity. As shown in Figure 7(a), each box can be considered a storage unit, and the number of storage units is the same as the number of bits in the preloaded seed. That is, each storage unit is used to input the corresponding bit in the seed. For example, if the seed length is 10 bits, it can be represented in binary as b9, b8, b7, b6, b5, b4, b3, b2, b1, b0, then 10 corresponding storage units are used. Of course, the seed can also be represented in hexadecimal or decimal. When it is used in operation with the target polynomial, it needs to be converted to binary form. For example, 0110111000 is represented as 0x1B8 in hexadecimal and 440 in decimal.

[0088] It should be noted that the polynomial x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1 can be written as x^10+a9×(x^9)+a8×(x^8)+a7×(x^7)+a6×(x^6)+a5×(x^5)+a4×(x^4)+a3×(x^3)+a2×(x^2)+a1×x+1. It should be understood that x can also be written as x^1.

[0089] Figure 7(b) is a schematic diagram of the second pilot symbol generation structure in an embodiment of this application. The target polynomial is a 9th-order polynomial, which can be expressed as: x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2+a1×x+1. Where a8…a1 can take values ​​of 0 or 1. In some specific applications, the number of non-zero terms in a8…a1 is no greater than 6, meaning the number of terms in the target polynomial is greater than or equal to 2 and less than or equal to 8, resulting in lower hardware implementation complexity. As shown in Figure 7(b), the seed length is 9 bits, which can be represented in binary as b8, b7, b6, b5, b4, b3, b2, b1, b0. Of course, the seed can also be represented in hexadecimal or decimal, but it needs to be converted to binary form when operating with the target polynomial.

[0090] Figure 7(c) is a schematic diagram of the fourth pilot symbol generation structure in the embodiments of this application. The target polynomial is an 11th-order polynomial, and the 8th-order polynomial can be expressed as: x 11 +a 10 ×x 10 +a9×x 9 +a8×x 8 +a7×x 7 +a6×x 6 +a5×x 5 +a4×x 4 +a3×x 3 +a2×x 2 +a1×x+1. Where a 10 …a1 can take the value 0 or 1. In some specific applications, a… 10 …The number of non-zero terms in a1 is no greater than 6, meaning the number of terms in the objective polynomial is greater than or equal to 2 and less than or equal to 8, resulting in low hardware implementation complexity. As shown in Figure 7(c), the seed length is 11 bits, which can be represented in binary as b. 10 b9, b8, b7, b6, b5, b4, b3, b2, b1, b0. Of course, the seed can also be represented in hexadecimal or decimal, but it needs to be converted to binary form when it is used in operation with the target polynomial.

[0091] In Figures 7(a), 7(b), and 7(c), for scenarios requiring the generation of M pilot symbols in one polarization direction, a bit sequence b0, b1, b2, ... b1, consisting of 2 × M bits, is obtained based on the target polynomial and the seed. 2M-1 The aforementioned bit sequence is also called a pseudo-random binary sequence (PRBS). A bit sequence generated using a 9th-order polynomial is also called PRBS9, a bit sequence generated using a 10th-order polynomial is also called PRBS10, and a bit sequence generated using an 11th-order polynomial is also called PRBS11. Bit sequence b0, b1, b2, ... b 2M-1 Each pair of consecutive bits is denoted as b. 2t b 2t+1(0 ≤ t < M). The two bits b 2t , b 2t+1 are used to map to one of the M pilot symbols. At this time, b 2t and b 2t+1 are mapped to a symbol (2b 2t - 1)A + (2b 2t+1 - 1)Aj, 0 ≤ t < M.

[0092] It should be noted that the symbol (2b 2t - 1)A + (2b 2t+1 - 1)Aj may not be a symbol on the constellation diagram of the modulation format used. It can be four symbols in the middle area between the outermost 4 symbols and the innermost 4 symbols of the constellation diagram of the modulation format used. At this time, the noise and sensitivity of the training and pilot symbols are average, but the peak-to-average power ratio is relatively low. Taking 16QAM as an example, the 16 symbols on the 16QAM constellation diagram take values of {±1 ± 1j, ±1 ± 3j, ±3 ± 1j, ±3 ± 3j}, and the value of the real number A satisfies 1 ≤ A ≤ 3. The specific value of the real number A can be selected according to the actual application scenario to make the peak-to-average power ratio, noise and sensitivity of the training and pilot symbols have a good compromise. For example, the real number The values of the pilot symbols and the training symbols are In addition, when the 16 symbols on the 16QAM constellation diagram are power-normalized and take values of The value of the real number A satisfies For example, the real number The values of the pilot symbols and the training symbols are

[0093] In the embodiments of the present application, the target polynomial and the seed determined by designing the value of the coefficient a i in the polynomial can be used to make the autocorrelation characteristics of the symbol sequences of the generated pilot symbols in the X polarization and Y polarization better, and the cross-correlation characteristics of the symbol sequences of the two polarizations better. Among them, when the target polynomial adopts a 9th-order polynomial, 1 ≤ i ≤ 8; when the target polynomial adopts a 10th-order polynomial, 1 ≤ i ≤ 9; when the target polynomial adopts an 11th-order polynomial, 1 ≤ i ≤ 10; in particular, the normalized amplitude of the sidelobe value of the periodic autocorrelation function of the symbol sequences in the two polarization directions is not greater than a preset value T0, and the normalized amplitude of the periodic cross-correlation function value of the symbol sequences in the two polarization directions is not greater than a preset value T1.

[0094] Next, the N SF × T training symbols and N SF × M pilot symbols in the data frame are introduced together, a total of N SF × N TPThe symbols satisfy the DC balance method, where N TP =T+M-1.

[0095] Firstly, consider N TP It is an even number, that is, T+M is an odd number.

[0096] Typically, in one polarization direction, each subframe contains T training symbols and M pilot symbols combined, totaling N. TP =T+M-1 symbols satisfy DC balance. At this time, N in the data frame SF ×T training symbols and N SF ×M pilot symbols combined into a total of N SF ×N TP The symbol also satisfies DC balance. It should be understood that the N... TP The sum of the symbols is 0. More specifically, the N... TP The sum of the real parts of the complex numbers corresponding to each symbol is 0, and the sum of their imaginary parts is also 0. This achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiving end. Consider N... TP If T is even, then T is even and M is odd, or T is odd and M is even.

[0097] Consider T=11, M=226. Table 1 gives the parameter combinations of the data frame (superframe), including the number of symbols N before framing. CW The number of subframes N SF The number of symbols N in each subframe S The number of symbols N in a superframe F The number of frame synchronization symbols N FAW The number of reserved symbols N RES The parameter combination. Here, for each N... g =The first symbol among the 128 symbols is the pilot symbol.

[0098] Table 1

[0099] In each subframe, M=226 pilot symbols are generated from a target polynomial and seeds in two polarization directions. When the target polynomial and the seeds in hexadecimal representation in the two polarization directions are listed in a row of Table 2 below, the normalized amplitude of the sidelobe values ​​of the periodic autocorrelation function of pilot symbols in the same polarization direction is no greater than 0.3, and the normalized amplitude of the periodic cross-correlation function values ​​of pilot symbols in different polarization directions is no greater than 0.3. The superframe architecture provided in this application also has low frame redundancy, and the sequence autocorrelation and cross-correlation characteristics of the pilot symbols are good. The combination of training symbols and pilot symbols can also satisfy DC balance, which is beneficial for improving the signal recovered at the receiver and improving the quality of the recovered signal.

[0100] Table 2

[0101] When the target polynomial is a 10th-order polynomial, and the target polynomial and the seeds in hexadecimal representation in two polarization directions are in one row of Table 3 below, the normalized amplitude of the sidelobe value of the periodic autocorrelation function of the pilot symbol in the same polarization direction is not greater than 0.3, and the normalized amplitude of the periodic cross-correlation function value of the pilot symbol in different polarization directions is not greater than 0.3.

[0102] Table 3

[0103] Example 1:

[0104] Considering the number of symbols before framing is N CW =172032, the data frame contains N SF = 6 subframes, each subframe contains N S = 28928 symbols. The first type of subframe contains N FAW = 22 frame synchronization symbols, N RET =98, T=11 training symbols and M=226 pilot symbols; the second type of subframe contains T=11 training symbols and M=226 pilot symbols. In each subframe, the pilot symbol sequence and the training symbol sequence are the same. For example, the 11 training symbols in the first subframe are the same as the 11 training symbols in the second subframe. Consider the sequence of 11 training symbols as shown in Table 4 below.

[0105] Table 4

[0106] The first symbol in each subframe is both a pilot symbol and a training symbol. In the X-polarization direction, the first symbol of the 226 pilot symbols has a value of -A+Aj; in the Y-polarization direction, the first symbol of the 226 pilot symbols has a value of -A-Aj. These 226 pilot symbols are generated based on the target polynomial and its corresponding seed, with specific parameters set in Table 2. For example, consider combination number 6 in Table 2, where the target polynomial is x^11+x^10+x^9+x^7+1, the seed in the X-polarization direction is 0x5B2, and the seed in the Y-polarization direction is 0x6B4. The generation process of the 226 pilot symbols can be understood by referring to Figure 8.

[0107] As shown in Figure 8, in the X-polarization direction, the input polarization seed is 0x5B2, which is converted to a binary sequence of 10110110010. If two consecutive bits of 1 and 0 are output in sequence, the pilot symbol in the X-polarization direction is A-Aj; if two consecutive bits of 0 are output in sequence, the pilot symbol in the X-polarization direction is -A-Aj; if two consecutive bits of 1 are output in sequence, the pilot symbol in the X-polarization direction is A+Aj; if two consecutive bits of 0 are output in sequence, the pilot symbol in the X-polarization direction is -A+Aj. And so on, 226 pilot symbols in the X-polarization direction can be obtained.

[0108] As shown in Figure 8, in the Y-polarization direction, the input polarization seed is 0x6B4, which is converted to a binary sequence of 11010110100. If two consecutive bits are output as 1 and 0, the pilot symbol in the Y-polarization direction is A-Aj; if two consecutive bits are output as 0, the pilot symbol in the Y-polarization direction is -A-Aj; if two consecutive bits are output as 1, the pilot symbol in the Y-polarization direction is A+Aj; and if two consecutive bits are output as 0, the pilot symbol in the Y-polarization direction is -A+Aj. This process continues, resulting in 226 pilot symbols in the Y-polarization direction.

[0109] The 226 pilot symbols are shown in Table 5.

[0110] Table 5

[0111] It should be noted that the pilot symbol sequence in Table 5 above can also be used for the superframe structure corresponding to the parameter combinations in Table 1.

[0112] The normalized amplitudes of the sidelobe values ​​of the periodic autocorrelation function of the pilot symbol sequences in both polarization directions and the normalized amplitudes of the sidelobe values ​​of the periodic cross-correlation function of the pilot symbol sequences in both polarization directions are both no greater than 0.15. The superframe architecture provided in this application also has low frame redundancy, and the sequence autocorrelation and cross-correlation characteristics of the pilot symbols are good. The combination of training symbols and pilot symbols can also satisfy DC balance, which is beneficial to improving the signal recovered at the receiver and improving the quality of the recovered signal.

[0113] Secondly, consider N TP It is an odd number, that is, T+M is an even number.

[0114] Due to N TP For an odd number of symbols, in one polarization direction, the T training symbols and M pilot symbols in a subframe combine to form a total of N. TP=T+M-1 symbols are insufficient to satisfy DC balance. Multiple subframes need to be combined together so that the training symbols and pilot symbols in the multiple subframes can be combined to satisfy DC balance.

[0115] Consider two subframes, the first and the second. The pilot sequences of the first and second subframes have the same symbol values ​​at M-1 positions, and the sum of the two symbols at one position is 0. In some specific applications, the pilot sequences of the first and second subframes have the same symbol values ​​at the first M-1 positions, and the sum of the two symbols at the last position is 0. Considering the symbols at the first M-1 positions of the pilot sequence of the first (or second) subframe, combined with T training symbols, a total of T+M-2 symbols are DC balanced.

[0116] At this time, N in the data frame SF ×T training symbols and N SF ×M pilot symbols combined into a total of N SF ×N TP The symbols also satisfy DC balance. For simplicity, the pilot sequence of the first subframe is simply referred to as the first pilot sequence, and the pilot sequence of the second subframe is simply referred to as the second pilot sequence.

[0117] In one polarization direction, N of a data frame SF In each of the two subframes, the M pilot symbols are the first pilot sequence, and the other N... SF The M pilot symbols in each of the two subframes are the second pilot sequence. At this time, N in the data frame SF ×T training symbols and N SF ×M pilot symbols combined into a total of N SF ×N TP The symbol also satisfies DC balance. It should be understood that the N... SF ×N TP The sum of the symbols is 0. More specifically, the N... SF ×N TP The sum of the real parts of the complex numbers corresponding to each symbol is 0, and the sum of their imaginary parts is also 0. This achieves DC balance, which is beneficial for improving the quality of the recovered signal at the receiving end. Consider N... TP If T is odd, then T is even and M is even, or T is odd and M is odd.

[0118] Consider T=11, M=113. Table 6 gives some parameter combinations for data frames (superframes), including the number of symbols N before framing. CW The number of subframes N SF The number of symbols N in each subframe S The number of symbols N in a superframe FThe number of frame synchronization symbols N FAW The number of reserved symbols N RES The parameter combination. Here, for each N... g =The first symbol among the 128 symbols is the pilot symbol.

[0119] Table 6

[0120] For the first pilot sequence, the M=113 pilot symbols it contains are generated by a target polynomial and seeds in two polarization directions. When the target polynomial and the seeds in hexadecimal representation in the two polarization directions are in one row of Table 7 below, the normalized amplitude of the sidelobe value of the periodic autocorrelation function of the pilot symbols in the same polarization direction is no greater than 0.3, and the normalized amplitude of the periodic cross-correlation function value of the pilot symbols in different polarization directions is no greater than 0.3.

[0121] Table 7

[0122] It should be noted that the first pilot sequence is generated from the target polynomial and seeds in two polarization directions. Compared to the first pilot sequence, the second pilot sequence has the same symbol values ​​at M-1 positions, and the sum of the two symbols at one position is 0. Typically, the symbol values ​​at the first M-1 positions are the same, and the sum of the two symbols at the last position is 0. In some specific applications, the second pilot sequence is generated by generating M symbols from the target polynomial and seeds in two polarization directions, and then inverting the real and imaginary parts of the last symbol among the M symbols. Simply put, the second pilot sequence is generated from the target polynomial and seeds in two polarization directions. This inversion operation, for example, changes A to -A and A to -A.

[0123] Example 2:

[0124] Considering the number of symbols before framing is NCW =172032, the data frame contains N SF = 12 subframes, each subframe contains N S = 14464 symbols. The first type of subframe contains N FAW = 22 frame synchronization symbols, N RES =38, T=11 training symbols and M=113 pilot symbols; the second type of subframe contains T=11 training symbols and M=113 pilot symbols. In each subframe, the pilot symbol sequence and the training symbol sequence are the same. For example, the 11 training symbols in the first subframe are the same as the 11 training symbols in the second subframe. Consider the sequence of 11 training symbols as shown in Table 4 above.

[0125] The first symbol in each subframe is both a pilot symbol and a training symbol. In the X-polarization direction, the first symbol of the 113 pilot symbols has a value of -A+Aj; in the Y-polarization direction, the first symbol of the 113 pilot symbols has a value of -A-Aj. Six subframes in the data frame use the first pilot sequence, and the other six subframes use the second pilot sequence. Compared to the second pilot sequence, the first pilot sequence has the same symbol value for the first M-1 positions, and the sum of the two symbols at the last position is 0.

[0126] The 113 pilot symbols in the first pilot sequence are generated based on the target polynomial and its corresponding seed, with specific parameters set as a combination of parameters in Table 7. For example, consider the combination numbered 18 in Table 7, where the target polynomial is x^10+x^9+x^7+x^6+1, the seed for the X-polarization direction is 0x002, and the seed for the Y-polarization direction is 0x37C. The generation process of the 113 pilot symbols can be understood by referring to Figure 9.

[0127] As shown in Figure 9, in the X-polarization direction, the input polarization seed is 0x002, which is converted to a binary sequence of 0000000010. If two consecutive bits of 1 and 0 are output in sequence, the pilot symbol in the X-polarization direction is A-Aj; if two consecutive bits of 0 are output in sequence, the pilot symbol in the X-polarization direction is -A-Aj; if two consecutive bits of 1 are output in sequence, the pilot symbol in the X-polarization direction is A+Aj; if two consecutive bits of 0 are output in sequence, the pilot symbol in the X-polarization direction is -A+Aj. And so on, 113 pilot symbols in the X-polarization direction can be obtained.

[0128] As shown in Figure 9, in the Y-polarization direction, the input polarization seed is 0x37C, which is converted to a binary sequence of 1101111100. If two consecutive bits are output as 1 and 0, the pilot symbol in the Y-polarization direction is A-Aj; if two consecutive bits are output as 0, the pilot symbol in the Y-polarization direction is -A-Aj; if two consecutive bits are output as 1, the pilot symbol in the Y-polarization direction is A+Aj; and if two consecutive bits are output as 0, the pilot symbol in the Y-polarization direction is -A+Aj. This process continues, resulting in 113 pilot symbols in the Y-polarization direction.

[0129] The 113 pilot symbols in the first pilot sequence are shown in Table 8.

[0130] Table 8

[0131] It should be noted that the pilot symbol sequence in Table 8 above can also be used for the superframe structure corresponding to the parameter combinations in Table 6.

[0132] For the first pilot sequence in Table 8 above, the normalized amplitudes of the sidelobe values ​​of the periodic autocorrelation function of the pilot symbol sequences in both polarization directions and the normalized amplitudes of the sidelobe values ​​of the periodic cross-correlation function of the pilot symbol sequences in both polarization directions are both no greater than 0.2. Furthermore, for the second pilot sequence corresponding to the first pilot sequence, the normalized amplitudes of the sidelobe values ​​of the periodic autocorrelation function of the pilot symbol sequences in both polarization directions and the normalized amplitudes of the sidelobe values ​​of the periodic cross-correlation function of the pilot symbol sequences in both polarization directions are both no greater than 0.2.

[0133] The superframe architecture provided in this application also has low frame redundancy, and the sequence autocorrelation and cross-correlation characteristics of the pilot symbols are good. The combination of training symbols and pilot symbols can also satisfy DC balance, which is beneficial to improving the signal recovery at the receiver and improving the quality of the recovered signal.

[0134] Example 3:

[0135] Considering the number of symbols before framing is N CW =344064, the data frame contains N SF = 24 subframes, each subframe contains N S = 14464 symbols. The first type of subframe contains N FAW = 22 frame synchronization symbols, N RES=98, T=11 training symbols and M=113 pilot symbols; the second type of subframe contains T=11 training symbols and M=113 pilot symbols. In each subframe, the pilot symbol sequence and the training symbol sequence are the same. For example, the 11 training symbols in the first subframe are the same as the 11 training symbols in the second subframe. Consider the sequence of 11 training symbols as shown in Table 4 above.

[0136] The first symbol in each subframe is both a pilot symbol and a training symbol. In the X-polarization direction, the first symbol of the 113 pilot symbols has a value of -A+Aj; in the Y-polarization direction, the first symbol of the 113 pilot symbols has a value of -A-Aj. Twelve subframes in the data frame use the first pilot sequence, and the other twelve subframes use the second pilot sequence. Compared to the second pilot sequence, the first M-1 positions of the first pilot sequence have the same symbol value, and the sum of the two symbols at the last position is 0.

[0137] The 113 pilot symbols in the first pilot sequence are generated based on the target polynomial and its corresponding seed, with specific parameters set in Table 7. For example, consider the combination numbered 5 in Table 7, where the target polynomial is x^11+x^10+x^7+x^3+1, the seed for the X-polarization direction is 0x186, and the seed for the Y-polarization direction is 0x704. The generation process of the 113 pilot symbols can be understood by referring to Figure 10.

[0138] As shown in Figure 10, in the X-polarization direction, the input polarization seed is 0x186, which is converted to a binary sequence of 00110000110. If two consecutive bits of 1 and 0 are output in sequence, the pilot symbol in the X-polarization direction is A-Aj; if two consecutive bits of 0 are output in sequence, the pilot symbol in the X-polarization direction is -A-Aj; if two consecutive bits of 1 are output in sequence, the pilot symbol in the X-polarization direction is A+Aj; if two consecutive bits of 0 are output in sequence, the pilot symbol in the X-polarization direction is -A+Aj. And so on, 113 pilot symbols in the X-polarization direction can be obtained.

[0139] As shown in Figure 10, in the Y-polarization direction, the input polarization seed is 0x704, which is converted to a binary sequence of 11100000100. If two consecutive bits are output as 1 and 0, the pilot symbol in the Y-polarization direction is A-Aj; if two consecutive bits are output as 0, the pilot symbol in the Y-polarization direction is -A-Aj; if two consecutive bits are output as 1, the pilot symbol in the Y-polarization direction is A+Aj; and if two consecutive bits are output as 0, the pilot symbol in the Y-polarization direction is -A+Aj. This process continues, resulting in 113 pilot symbols in the Y-polarization direction.

[0140] The 113 pilot symbols in the first pilot sequence are shown in Table 9.

[0141] Table 9

[0142] It should be noted that the pilot symbol sequence in Table 9 above can also be used for the superframe structure corresponding to the parameter combinations in Table 6.

[0143] For the first pilot sequence in Table 9 above, the normalized amplitudes of the sidelobe values ​​of the periodic autocorrelation function of the pilot symbol sequences in both polarization directions and the normalized amplitudes of the sidelobe values ​​of the periodic cross-correlation function of the pilot symbol sequences in both polarization directions are both no greater than 0.2. Furthermore, for the second pilot sequence corresponding to the first pilot sequence, the normalized amplitudes of the sidelobe values ​​of the periodic autocorrelation function of the pilot symbol sequences in both polarization directions and the normalized amplitudes of the sidelobe values ​​of the periodic cross-correlation function of the pilot symbol sequences in both polarization directions are both no greater than 0.2.

[0144] The superframe architecture provided in this application also has low frame redundancy, and the sequence autocorrelation and cross-correlation characteristics of the pilot symbols are good. The combination of training symbols and pilot symbols can also satisfy DC balance, which is beneficial to improving the signal recovery at the receiver and improving the quality of the recovered signal.

[0145] Figure 11 is a schematic diagram of a data transmission device according to an embodiment of this application. This data transmission device is applied at the transmitting end. As shown in Figure 11, the data transmission device includes a processing unit 201 and a transmitting unit 202. The processing unit 201 is used to acquire a data frame including multiple subframes, and to generate multiple pilot symbols included in the subframes based on the target polynomial and seed given in the above embodiments; optionally, it is also used to generate training symbols; specific implementation methods have been described in previous embodiments and will not be repeated here. The transmitting unit 202 is used to perform the action of transmitting the data frame in the above embodiments.

[0146] Figure 12 is a schematic diagram of another structure of the data transmission device in this embodiment. This data transmission device is applied at the receiving end. As shown in Figure 12, the data transmission device includes a receiving unit 302, which receives a second data frame transmitted through a channel from a first data frame. The first data frame has multiple subframes, consistent with the data frame including multiple subframes at the sending end; this will not be described further in this embodiment. Optionally, the data transmission device also includes a processing unit 301, which performs decoding and other operations.

[0147] It should be understood that the data transmission devices provided in Figures 11 and 12 can also be implemented in other ways. For example, the unit division in the above devices is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system. In addition, the functional units in the various embodiments of this application may be integrated into one processing unit, or they may be independent physical units, or two or more functional units may be integrated into one processing unit. The integrated units described above can be implemented in hardware or as software functional units.

[0148] Figure 13 is a schematic diagram of an optical module structure according to an embodiment of this application. As shown in Figure 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 used to receive signals from other devices and transmit them to the processor 401 or to send signals from the processor 401 to other devices. Optionally, the optical module may also include a memory 403, wherein the memory 403 is used to store program instructions and data.

[0149] In one possible scenario, the optical module is used at the transmitting end, and the processor 401 is used to acquire a data frame including multiple subframes, and to generate multiple pilot symbols included in the subframes based on the target polynomial and seed given in the above embodiments; optionally, it is also used to generate training symbols; the specific implementation has been described in the previous embodiments, and will not be repeated here. For example, the processor 401 includes the processing unit 201 shown in FIG11. As an example, the processor 401 performs the operations in the above embodiments to obtain a data frame, and sends the data frame through interface 402. In this example, interface 402 can specifically refer to an electrical interface. As another example, the processor 401 performs the operations in the above embodiments to obtain a data frame, and the modulator in the optical module performs signal processing such as electro-optic conversion according to the data frame to obtain an optical signal, and then sends the optical signal through interface 402. In this example, interface 402 can specifically refer to an optical interface.

[0150] In another possible scenario, the optical module is applied at the receiving end, and the processor 401 is used to execute the operations of the receiving unit 302 in the above embodiments. Alternatively, the processor 401 can be described as including the processing unit 301 shown in Figure 12. As an example, the interface receives an optical signal transmitted through a channel. The demodulator in the optical module performs signal processing such as photoelectric conversion on the optical signal to obtain a data frame. The processor 401 performs the operations described in the above embodiments on this data frame. In this example, the interface 402 specifically refers to an optical interface. As another example, the demodulator in the optical module performs signal processing such as photoelectric conversion on the received optical signal to obtain a data frame, and transmits the data frame to the processor 401 through the interface 402. The processor 401 performs the operations described in the above embodiments on this data frame. In this example, the interface 402 specifically refers to an electrical interface.

[0151] Typically, an optical module consists of optoelectronic devices, a processor, and an interface. The optoelectronic devices include transmitting and receiving devices. The transmitting end of the optical module converts electrical signals into optical signals and transmits them through optical fibers. The receiving end of the optical module receives the optical signals and converts them back into electrical signals.

[0152] It should be noted that the types of optical modules in this application embodiment include, but are not limited to, normal optical modules, near package optics (NPO) modules, and co-packaged optics (CPO) modules. Normal optical modules can perform functions including, but not limited to, digital signal processing (DSP) and clock data recovery (CDR). For example, a normal optical module converts analog signals to digital signals, performs DSP on the digital signals, and then converts them back to analog signals before sending them to the host device. Because DSP requires retiming, a normal optical module can also be called a retimed module. Normal optical modules are connected to the host device via an attachment unit interface (AUI). NPO and CPO modules do not have pluggable physical packaging and are closer to the host device. NPO and CPO modules can also be called optical engines. NPO or CPO technology is a technology that "packages" the host device (or host chip) and the optical engine. When NPO technology is used to encapsulate the host-side device and the optical engine, the optical engine can be called an NPO module. When CPO technology is used to encapsulate the host-side device and the optical engine, the optical engine can be called a CPO module.

[0153] Figure 14 is a schematic diagram of a transmitting device according to an embodiment of this application. As shown in Figure 14, the transmitting device includes a host-side device 501 and an optical module 502. The host-side device 501 is used to send electrical signals to the optical module 502, and the optical module 502 converts the electrical signals into optical signals and transmits the optical signals through the channel. For example, the host-side device 501 may specifically be a switch, router, or server. The transmitting device can be a communication device including the host-side device 501 and the optical module 502. It should also be understood that the transmitting devices in the embodiments of this application are named based on the data flow direction and do not limit the function of the device. For example, the transmitting device may also have a receiving function.

[0154] Figure 15 is a schematic diagram of a receiving device in an embodiment of this application. As shown in Figure 15, the receiving device includes a host-side device 601 and an optical module 602. The optical module 602 is used to convert the received optical signal into an electrical signal and send the electrical signal to the host-side device 601. For example, the host-side device 601 may specifically be a switch, router, or server. The receiving device can be a communication device including the host-side device 601 and the optical module 602. It should also be understood that the receiving device in the embodiments of this application is named based on the data flow direction and does not limit the function of the device. For example, the receiving device may also have a sending function.

[0155] This application also provides an optical transport network (OTN) device, which includes line-side equipment and client-side equipment. The client-side equipment may also be referred to as a tributary-side equipment in some scenarios. The line-side equipment includes a processor and an interface. In one possible scenario, the OTN device is used at the transmitting end, and the processor is used to perform the operation of step 101 in the above embodiment. In another possible scenario, the OTN device is used at the receiving end, and the processor is used to perform the operation of step 103 in the above embodiment. The interface can be a transceiver or an input / output interface, used to receive signals from other devices besides the line-side equipment and transmit them to the processor, or to send signals from the processor to other devices besides the line-side equipment.

[0156] This application also provides a chip. The chip integrates circuitry for implementing the functions of the processor 401 described above, and one or more interfaces. As an example, the chip integrates a memory. As another example, when the chip does not integrate a memory, it can be connected to an external memory via the interface. The chip can perform the method steps of any one or more of the foregoing embodiments. Alternatively, the chip can implement the actions performed by the processing and transmission device in the foregoing embodiments based on program code stored in the memory.

[0157] As an example, the chip in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor, any conventional processor, or a processing circuit that implements a specific function.

[0158] This application also provides a computer-readable storage medium including a program or instructions that, when run on a computer, cause the method performed as described in the above method embodiments to be implemented.

[0159] It should be understood that the processor mentioned in the embodiments of this application can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit, integrated circuit, etc. When implemented in software, the processor can be a general-purpose processor that reads software code stored in memory. The memory can exist independently and be connected to the processor, or the memory can be integrated with the processor.

[0160] As an example, the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor, any conventional processor, or a processing circuit that implements a specific function.

[0161] In embodiments of this application, the memory may be random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium may also be a component of the processor. The processor and storage medium may reside in an ASIC. Additionally, the ASIC may reside in a network device or a terminal device. Alternatively, the processor and storage medium may exist as discrete components in the network device or terminal device.

[0162] In the above embodiments, it can be implemented entirely or partially by software, hardware, firmware, or any combination thereof.

[0163] When implemented in hardware, the data transmission method provided in this application embodiment may be implemented without reading software code or instructions. For example, it may be implemented by CPU, DSP, ASIC, FPGA, other programmable logic devices, transistor logic devices, hardware components, or any combination thereof.

[0164] When implemented using software, it can be implemented entirely or partially in the form of a computer program product. A computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, all or part of the processes or functions of the embodiments of this application are performed. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a terminal device, or other programmable device. The computer program or instructions can be stored in or transmitted through a computer-readable storage medium. The computer-readable storage medium can be any available medium that a computer can access, or a data storage device such as a server that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital versatile disc (DVD); or it can be a semiconductor medium, such as a solid-state disk (SSD).

[0165] Finally, it should be noted that the above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A data transmission method, characterized in that, include: Acquire a data frame comprising multiple subframes. In one polarization direction, the subframe comprises 226 pilot symbols. The 226 pilot symbols are generated by a target polynomial and a seed, wherein the target polynomial is x^11+x^10+x^9+x^7+1. Send the data frame.

2. The method according to claim 1, characterized in that, The seed for the X-polarization direction is 0x5B2, and the seed for the Y-polarization direction is 0x6B4.

3. The method according to claim 1 or 2, characterized in that, In one polarization direction, the subframe also includes 11 training symbols.

4. The method according to any one of claims 1-3, characterized in that, The sequences of the training symbols are respectively in the X and Y polarization directions as follows:

5. The method according to any one of claims 1-4, characterized in that, In one polarization direction, the subframe includes 28928 symbols.

6. The method according to any one of claims 1-5, characterized in that, The 226 pilot symbols are respectively in the X and Y polarization directions as follows:

7. A data transmission method, characterized in that, include: The first data frame is received after being transmitted through the channel. The first data frame includes multiple subframes. In one polarization direction, each subframe includes 226 pilot symbols. The 226 pilot symbols are generated by a target polynomial and a seed. The target polynomial is x^11+x^10+x^9+x^7+1.

8. The method according to claim 7, characterized in that, The seed for the X-polarization direction is 0x5B2, and the seed for the Y-polarization direction is 0x6B4.

9. The method according to claim 7 or 8, characterized in that, In one polarization direction, the subframe also includes 11 training symbols.

10. The method according to any one of claims 7-9, characterized in that, The sequences of the training symbols are respectively in the X and Y polarization directions as follows:

11. The method according to any one of claims 7-10, characterized in that, In one polarization direction, the subframe includes 28928 symbols.

12. The method according to any one of claims 7-11, characterized in that, The 226 pilot symbols are respectively in the X and Y polarization directions as follows:

13. A data transmission device, characterized in that, include: Processing unit and sending unit; The processing unit is configured to: acquire a data frame comprising multiple subframes, wherein, in one polarization direction, the subframe data frame comprises 226 pilot symbols, the 226 pilot symbols being generated by a target polynomial and a seed, wherein the target polynomial is x^11+x^10+x^9+x^7+1; The sending unit is used to send the data frame.

14. A data transmission device, characterized in that, include: Receiving unit; The receiving unit is configured to: receive a second data frame transmitted through the channel from the first data frame, wherein the first data frame includes multiple subframes, and in one polarization direction, the subframes include 226 pilot symbols, wherein the 226 pilot symbols are generated by a target polynomial and a seed, wherein the target polynomial is x^11+x^10+x^9+x^7+1.

15. A chip, characterized in that, The chip is used to perform the method as described in any one of claims 1 to 12.

16. An optical module, characterized in that, The optical module includes a processor and an interface, the interface being used for transmitting and receiving signals, and the processor being used for performing the method as described in any one of claims 1 to 6.

17. A transmitting device, characterized in that, The transmitting device includes a host-side device and an optical module as described in claim 16, wherein the optical module is used to convert electrical signals from the host-side device into optical signals and transmit the optical signals.

18. An optical module, characterized in that, The optical module includes a processor and an interface, the interface being used for transmitting and receiving signals, and the processor being used for performing the method as described in any one of claims 7-12.

19. A receiving device, characterized in that, The receiving device includes a host-side device and an optical module as described in claim 18, wherein the optical module is used to convert the received optical signal into an electrical signal and send the electrical signal to the host-side device.

20. A communication system, characterized in that, include: The transmitting device as claimed in claim 17 and the receiving device as claimed in claim 19, wherein the transmitting device is configured to transmit a signal to the receiving device.

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