Data transmission method, apparatus, device, and system

Abstract

A data transmission method and apparatus, a device, and a system, relating to the technical field of optical communications. In the method, in W dual-polarization symbol streams, in any polarization direction, an i-th pilot symbol of each subframe in a first superframe is separated from an i-th pilot symbol of each subframe in a second superframe by m symbols. Since the first superframe and the second superframe are transmitted in parallel in a time dimension, an equivalent pilot symbol interval is m, and m is less than NPG. In this way, when a receiver performs joint recovery processing on W dual-polarization symbol streams, a pilot symbol interval used for carrier phase recovery processing can be regarded as becoming smaller, thereby further improving dispersion tolerance, resulting in stronger phase noise tolerance capabilities, and being better suited for scenarios involving multi-subcarrier transmission.

Description

Methods, apparatus, equipment and systems for data transmission

[0001] This application claims priority to Chinese patent application filed on February 19, 2025, with application number 202510186385.3 and entitled "Method, Apparatus, Device and System for Data Transmission", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical communication technology, and in particular to a method, apparatus, device and system for data transmission. 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 frame the sequence of symbols to be transmitted before sending them. This involves adding some pre-designed symbol sequences to make it easier for the receiver to recover the transmitted symbols.

[0004] Current framing schemes are mainly applied to single-carrier transmission scenarios of 400 gigabits per second (Gbps) or 800 Gbps, and cannot adapt to future scenarios using multi-subcarrier transmission. For example, 800 Gbps multi-subcarrier transmission using quadrature phase shift keying (QPSK) modulation, 1.2 Tbps multi-subcarrier transmission using quadrature amplitude modulation (QAM), and 1.6 Tbps multi-subcarrier transmission using 16 QAM modulation. Summary of the Invention

[0005] This application provides a method, apparatus, device, and system for data transmission, and presents a framing scheme for multi-subcarrier transmission, which is beneficial for improving the quality of signal recovery at the receiving end. The technical solution adopted is as follows:

[0006] In a first aspect, this application provides a data transmission method, the method comprising: transmitting W dual-polarization symbol streams, wherein a first dual-polarization symbol stream includes a first superframe, and a second dual-polarization symbol stream includes a second superframe; in any polarization direction, every consecutive N subframes of the first superframe and the second superframe...PG Each symbol includes a pilot symbol, and the i-th pilot symbol of each subframe of the first superframe is the i-th group of consecutive N symbols. PG The j-th symbol in the set of symbols, and the i-th pilot symbol in each subframe of the second superframe is the i-th group of consecutive N symbols. PG The (j+m)th symbol in the set of symbols, W is greater than 1, i is greater than or equal to 1, j and m are positive integers, and j+m is less than or equal to N. PG It should be understood that the first symbol of a subframe is called the first symbol of the subframe. The first group of consecutive N... PG The symbol is N, which is the first N in the subframe. PG A symbol.

[0007] In the scheme shown in this application, a dual-polarization symbol stream comprises multiple superframes, each superframe being a collection of multiple dual-polarization symbols. These multiple superframes constitute a dual-polarization symbol stream for transmission.

[0008] In W dual-polarization symbol streams, the i-th pilot symbol of each subframe in the first superframe is m symbols away from the i-th pilot symbol of each subframe in the second superframe. Considering that the first and second superframes are transmitted in parallel in the time dimension, that is, using this method of transmission, the equivalent number of pilot symbol intervals is m, which is less than N. PG Thus, when the receiver performs joint recovery processing on W dual-polarization symbol streams, the pilot symbol spacing used for carrier phase recovery processing can be considered smaller, further improving anti-dispersion capability and phase-noise tolerance capability, making it more suitable for multi-subcarrier transmission scenarios.

[0009] Secondly, this application provides a data transmission method, the method comprising: receiving W dual-polarization symbol streams obtained through transmission, wherein the first dual-polarization symbol stream of the W dual-polarization symbol streams includes a first superframe, and the second dual-polarization symbol stream includes a second superframe; in any polarization direction, every consecutive N subframes of the first superframe and the second superframe... PG Each symbol includes a pilot symbol, and the i-th pilot symbol of each subframe of the first superframe is the i-th group of consecutive N symbols. PG The j-th symbol in the set of symbols, and the i-th pilot symbol in each subframe of the second superframe is the i-th group of consecutive N symbols. PG The (j+m)th symbol in a set of symbols has W greater than 1, i greater than or equal to 1, and j less than or equal to N. PG m is less than N PG And greater than 0, j+m less than or equal to N PG It should be understood that the first symbol of a subframe is called the first symbol of the subframe. The first group of consecutive N... PGThe symbol is N, which is the first N in the subframe. PG A symbol.

[0010] Combining the first or second aspect, the following options are available:

[0011] In one alternative approach, m and (N) PG / W)×a related, 1≤a<W, where a is an integer, making this data transmission method applicable to various values ​​of W, for example, W equals 4, m=(N PG / W)×a, where a is 1, 2 or 3.

[0012] In one alternative approach, m is greater than or equal to 16. This ensures that the value of m is not too small, thus preventing the pilot symbol spacing used for carrier phase recovery processing from becoming too small.

[0013] In one alternative approach, W is 2 and N PG The value is 64, and m is 32. Thus, in W dual-polarization symbol streams, the i-th pilot symbol of each subframe in the first superframe is 32 symbols apart from the i-th pilot symbol of each subframe in the second superframe. Considering that the first and second superframes are transmitted in parallel in the time dimension, i.e., using this method of transmission, the equivalent number of pilot symbol intervals is 32, which is less than N. PG Thus, when the receiver performs joint recovery processing on W dual-polarization symbol streams, the pilot symbol spacing used for carrier phase recovery processing can be considered smaller, further improving dispersion resistance and phase noise tolerance, making it more suitable for multi-subcarrier transmission scenarios. Moreover, with m = 32, for pilot symbols other than the first and last ones, the symbol spacing with the preceding and following pilot symbols is 32, which is stronger than the case where the symbol spacing is unequal. For example, with m = 16, the symbol spacing of the i-th pilot symbol with the preceding pilot symbol is 16, and the symbol spacing with the following pilot symbol is 48. The dispersion resistance depends on the larger symbol spacing of 48; generally, the larger the symbol spacing, the weaker the dispersion resistance. Therefore, compared to the case where the symbol spacing is 32, the dispersion resistance is weaker when m = 16.

[0014] In one alternative approach, when W is 4, the third dual-polarized symbol stream in the W dual-polarized symbol streams includes a third superframe, and the fourth dual-polarized symbol stream includes a fourth superframe. In any polarization direction, every consecutive N subframes of the third and fourth superframes... PG Each symbol includes a pilot symbol, and the i-th pilot symbol of each subframe of the third superframe is the i-th group of consecutive N symbols. PGThe (j+2m)th symbol in the set of symbols, and the i-th pilot symbol of each subframe of the fourth superframe is the i-th group of consecutive N symbols. PG The (j+3m)th symbol among the symbols, where j+2m is less than or equal to N. PG j+2m is less than or equal to N PG .

[0015] In the scheme shown in this application, in W dual-polarization symbol streams, the i-th pilot symbol of each subframe in the first superframe is spaced m symbols apart from the i-th pilot symbol of each subframe in the second superframe, the i-th pilot symbol of each subframe in the second superframe is spaced m symbols apart from the i-th pilot symbol of each subframe in the third superframe, and the i-th pilot symbol of each subframe in the third superframe is spaced m symbols apart from the i-th pilot symbol of each subframe in the fourth superframe. Considering that the four superframes are transmitted in parallel in the time dimension, that is, using this method of transmission, the equivalent number of pilot symbol intervals is m, which is less than N. PG Thus, when the receiver performs joint recovery processing on W dual-polarization symbol streams, the pilot symbol spacing used for carrier phase recovery processing can be considered smaller, further improving anti-dispersion capability and phase noise tolerance, making it more suitable for multi-subcarrier transmission scenarios.

[0016] In one alternative approach, N PG The value is 64, and m is 16. Thus, considering that the four superframes are transmitted in parallel in the time dimension, the equivalent pilot symbol spacing of this multi-carrier transmission scheme is 16, which is less than N. PG =64. When the receiver performs joint subcarrier recovery processing, the pilot symbol spacing used for carrier phase recovery processing can be considered to be reduced from 64 symbols to one-quarter, i.e., 16 symbols, further improving dispersion resistance, phase noise tolerance, and making it more suitable for multi-subcarrier transmission scenarios. Moreover, with m=16, for pilot symbols other than the first and last pilot symbols, the symbol spacing with the preceding pilot symbol is 16, and the symbol spacing with the following pilot symbol is also 16. Compared to the case where the symbol spacing is not equal, the dispersion resistance is stronger.

[0017] In one alternative approach, j is 1, which is more compatible with the current scheme, thus simplifying hardware implementation.

[0018] In one alternative approach, each superframe includes a frame synchronization symbol in any polarization direction, located at the end of any subframe within the superframe. This ensures that the frame synchronization symbol is positioned at the end of a subframe, making the implementation of the frame synchronization symbol at the receiver consistent and facilitating hardware implementation.

[0019] In one alternative approach, the frame synchronization symbol is located at the end of the last subframe in the superframe. This location of the frame synchronization symbol at the end of the superframe not only ensures consistency in the frame synchronization symbol implementation at the receiving end but also facilitates finding the frame synchronization symbol, thereby simplifying hardware implementation and reducing hardware complexity.

[0020] In one alternative approach, in any polarization direction, each superframe includes a first type of subframe. In each superframe, symbols other than training symbols, pilot symbols, payload symbols, and frame synchronization symbols are located after and adjacent to the training symbols in the first type of subframes. These symbols, excluding training symbols, pilot symbols, payload symbols, and frame synchronization symbols, can be called reserved symbols. Since reserved symbols are adjacent to training symbols, they are easier to find and facilitate hardware implementation.

[0021] In one alternative approach, the first type of subframe is the first subframe within the superframe. It should be understood that the first subframe is the very first subframe within the superframe.

[0022] In one alternative approach, in any polarization direction, in each superframe, symbols other than the training symbol, pilot symbol, payload symbol, and the frame synchronization symbol are located before and adjacent to the frame synchronization symbol.

[0023] In one alternative approach, the W dual-polarization symbol streams are carried on W subcarriers respectively. This allows for transmission using multiple subcarriers, improving dispersion resistance and providing better phase noise tolerance during joint subcarrier recovery processing at the receiver.

[0024] In one alternative approach, the W dual-polarization symbol streams are generated from a series of consecutive bits. This can also be understood as: distributing one bit stream to obtain W distributed bit streams, and then processing these W distributed bit streams through dual-polarization symbol mapping and framing to obtain the W dual-polarization symbol streams.

[0025] In one alternative approach, in any polarization direction, both the first and second superframes comprise 87,552 symbols, of which 86,016 are payload symbols; each subframe of the first and second superframes comprises 7,296 symbols. Alternatively, both the first and second superframes comprise 175,104 symbols, of which 172,023 are payload symbols; each subframe of the first and second superframes comprises 7,296 symbols. In this way, the bit data corresponding to the payload symbols comes from the data obtained through coding interleaving. This means that the framing scheme adopted is compatible with current 400ZR+, 800ZR, and 800ZR+ coding interleaving schemes, facilitating hardware implementation.

[0026] In one alternative approach, both the first and second superframes include 87,552 dual-polarization symbols, of which 86,016 are dual-polarization payload symbols; wherein each subframe of the first and second superframes includes 7,296 dual-polarization symbols; or, both the first and second superframes include 175,104 dual-polarization symbols, of which 172,023 are dual-polarization payload symbols; wherein each subframe of the first and second superframes includes 7,296 dual-polarization symbols.

[0027] In one alternative approach, N PG The options of 32, 64, or 128 can be well compatible with current solutions and facilitate hardware implementation.

[0028] In one alternative approach, in any polarization direction, each superframe includes a first type of subframe, whose frame synchronization symbol is located after and adjacent to the training symbols in that first type of subframe. This arrangement, with the frame synchronization symbol adjacent to the training symbols, only requires recording the position of one type of symbol, rather than both, simplifying hardware implementation.

[0029] In one alternative approach, in any polarization direction, within each superframe, symbols other than the training symbol, pilot symbol, payload symbol, and frame synchronization symbol are located after and adjacent to the frame synchronization symbol. These symbols, excluding the training symbol, pilot symbol, payload symbol, and frame synchronization symbol, can be referred to as reserved symbols. Since reserved symbols are adjacent to the frame synchronization symbol, they are easier to locate and facilitate hardware implementation.

[0030] In one alternative approach, each subframe of the first and second superframes includes 114 dual-polarization pilot symbols and 11 dual-polarization training symbols. The first pilot symbol among the 114 dual-polarization pilot symbols is the first training symbol among the 11 dual-polarization training symbols. In this way, the number of symbols in the superframe is equal to the parameters in current 800ZR / 800ZR+ framing, providing good compatibility with current DSP framing schemes for 800ZR and 800ZR+, and facilitating hardware implementation.

[0031] In one alternative approach, both the first and second superframes contain 22 dual-polarization frame synchronization symbols and either 26 or 74 dual-polarization reserved symbols. This ensures that the number of symbols in the superframes is equal to the parameters used in current 800ZR / 800ZR+ framing, providing good compatibility with current DSP framing schemes for 800ZR and 800ZR+, and facilitating hardware implementation.

[0032] In one alternative approach, the symbols in the subframe are either dual-polarization 16QAM symbols or dual-polarization QPSK symbols. This ensures that the superframe parameters are identical to those in current 800ZR / 800ZR+ framing, providing good compatibility with current DSP framing schemes for 800ZR and 800ZR+, and facilitating hardware implementation.

[0033] Thirdly, this application provides a data transmission method, which includes: transmitting two dual-polarization symbol streams, wherein the first dual-polarization symbol stream includes a first superframe, and the second dual-polarization symbol stream includes a second superframe; in any polarization direction, in each subframe of the first superframe, the first symbol out of every 64 consecutive symbols is a pilot symbol, and in each subframe of the second superframe, the 33rd symbol out of every 64 consecutive symbols is a pilot symbol. It should be understood that the first symbol of a subframe is called the first symbol of the subframe.

[0034] Fourthly, this application provides a data transmission method, which includes: receiving two dual-polarized symbol streams obtained through transmission, wherein the first dual-polarized symbol stream includes a first superframe, and the second dual-polarized symbol stream includes a second superframe; in any polarization direction, in each subframe of the first superframe, the first symbol out of every 64 consecutive symbols is a pilot symbol, and in each subframe of the second superframe, the 33rd symbol out of every 64 consecutive symbols is a pilot symbol. It should be understood that the first symbol of a subframe is called the first symbol of the subframe.

[0035] Combining the third or fourth aspect, the following options are available:

[0036] In one alternative approach, both the first and second superframes include 87,552 dual-polarization symbols, of which 86,016 are dual-polarization payload symbols; wherein each subframe of the first and second superframes includes 7,296 dual-polarization symbols; or, both the first and second superframes include 175,104 dual-polarization symbols, of which 172,023 are dual-polarization payload symbols; wherein each subframe of the first and second superframes includes 7,296 dual-polarization symbols.

[0037] In one alternative approach, in any polarization direction, both the first and second superframes include 87,552 symbols, of which 86,016 are payload symbols; wherein each subframe of the first and second superframes includes 7,296 symbols; or, in any polarization direction, both the first and second superframes include 175,104 symbols, of which 172,023 are payload symbols; wherein each subframe of the first and second superframes includes 7,296 symbols.

[0038] In one alternative approach, each subframe of the first and second superframes includes 114 dual-polarization pilot symbols and 11 dual-polarization training symbols, wherein the first pilot symbol among the 114 dual-polarization pilot symbols is the first training symbol among the 11 dual-polarization training symbols.

[0039] In one alternative approach, both the first and second superframes contain 22 dual-polarization frame synchronization symbols and 26 or 74 dual-polarization reserved symbols.

[0040] In one alternative approach, the symbols in the subframe are dual-polarization 16QAM symbols or dual-polarization QPSK symbols, which facilitates compatibility with current 400ZR+, 800ZR, and 800ZR+ coding interleaving schemes and is beneficial for hardware implementation.

[0041] In one alternative approach, each superframe includes a frame synchronization symbol in any polarization direction, the frame synchronization symbol being located at the end of any subframe within the superframe.

[0042] In one alternative approach, the frame synchronization symbol is located at the end of the last subframe in the superframe, in any polarization direction.

[0043] In one alternative approach, in any polarization direction, each superframe includes a first type of subframe, in which symbols other than training symbols, pilot symbols, payload symbols, and frame synchronization symbols are located after and adjacent to the training symbols in the first type of subframe.

[0044] In one alternative approach, the first type of subframe is the first subframe within the superframe. It should be understood that the first subframe is the very first subframe within the superframe.

[0045] In one alternative approach, in any polarization direction, in each superframe, symbols other than the training symbol, pilot symbol, payload symbol, and the frame synchronization symbol are located before and adjacent to the frame synchronization symbol.

[0046] In one alternative approach, the two dual-polarization symbol streams are carried on two subcarriers respectively.

[0047] In one alternative approach, the two dual-polarization symbol streams are generated from a series of consecutive bits.

[0048] In one alternative approach, in any polarization direction, each superframe includes a first type of subframe, the frame synchronization symbol of which is located after and adjacent to the training symbols in the first type of subframe.

[0049] In one alternative approach, in any polarization direction, in each superframe, symbols other than the training symbol, pilot symbol, payload symbol, and frame synchronization symbol are located after and adjacent to the frame synchronization symbol.

[0050] Fifthly, this application provides a data transmission apparatus comprising one or more modules, the one or more modules being configured to implement the method described in the first aspect or an optional manner of the first aspect, or the one or more modules being configured to implement the method described in the third aspect or an optional manner of the third aspect.

[0051] In a sixth aspect, this application provides a data transmission apparatus comprising one or more modules, the one or more modules being configured to implement the method described in the second aspect or an optional manner of the second aspect, or the one or more modules being configured to implement the method described in the fourth aspect or an optional manner of the fourth aspect.

[0052] In a seventh aspect, this application provides a chip for performing the methods described in the first, second, third, fourth, or alternative methods thereof.

[0053] Eighthly, this application provides an optical module including a processor and an interface, the interface being used for transmitting and receiving signals, and the processor being used to perform the methods described in the first, second, third, fourth, or alternative methods thereof.

[0054] Ninthly, this application provides a communication device, the communication device including a host-side device and an optical module as described in the eighth aspect, the host-side device being connected to the optical module, the optical module being used to convert electrical signals from the host-side device into optical signals and transmit the optical signals, or the optical module being used to convert received optical signals into electrical signals and transmit the electrical signals to the host-side device.

[0055] In a tenth aspect, this application provides a communication system comprising a plurality of communication devices as described in the ninth aspect, wherein the plurality of communication devices are configured to transmit optical signals to each other.

[0056] The beneficial effects of the above aspects can be referred to the beneficial effects of the first aspect, and will not be repeated here. Attached Figure Description

[0057] Figure 1 is a schematic diagram of the architecture of a communication system provided in an exemplary embodiment of this application;

[0058] Figure 2 is a schematic diagram of an embodiment of the digital signal processing (DSP) processor provided in an exemplary embodiment of this application;

[0059] Figure 3 is a schematic diagram of another embodiment of the originating DSP processor provided in an exemplary embodiment of this application;

[0060] Figure 4 is a schematic diagram of another embodiment of the originating DSP processor provided in an exemplary embodiment of this application;

[0061] Figure 5 is a schematic diagram of another embodiment of the originating DSP processor provided in an exemplary embodiment of this application;

[0062] Figure 6 is a schematic flowchart of a data transmission method provided in an exemplary embodiment of this application;

[0063] Figure 7 is a schematic diagram of a superframe structure provided in an exemplary embodiment of this application;

[0064] Figure 8 is a schematic diagram of another structure of a superframe provided in an exemplary embodiment of this application;

[0065] Figure 9 is a schematic diagram of another structure of a superframe provided in an exemplary embodiment of this application;

[0066] Figure 10 is a schematic diagram of symbol mapping provided in an exemplary embodiment of this application;

[0067] Figure 11 is a schematic diagram illustrating the relationship between subcarriers and superframes provided in an exemplary embodiment of this application;

[0068] Figure 12 is a schematic diagram of the relationship between superframes carried on two subcarriers provided in an exemplary embodiment of this application;

[0069] Figure 13 is a schematic diagram illustrating another relationship between superframes carried on two subcarriers provided in an exemplary embodiment of this application;

[0070] Figure 14 is a schematic diagram of another relationship between superframes carried on two subcarriers provided in an exemplary embodiment of this application;

[0071] Figure 15 is a schematic diagram illustrating another relationship between subcarriers and superframes provided in an exemplary embodiment of this application;

[0072] Figure 16 is a schematic diagram illustrating another relationship between superframes carried on two subcarriers provided in an exemplary embodiment of this application;

[0073] Figure 17 is a schematic diagram illustrating another relationship between superframes carried on two subcarriers provided in an exemplary embodiment of this application;

[0074] Figure 18 is a schematic diagram illustrating another relationship between superframes carried on two subcarriers provided in an exemplary embodiment of this application;

[0075] Figure 19 is a schematic diagram illustrating another relationship between subcarriers and superframes provided in an exemplary embodiment of this application;

[0076] Figure 20 is a schematic diagram of the relationship between superframes carried on four subcarriers provided in an exemplary embodiment of this application;

[0077] Figure 21 is a schematic diagram illustrating another relationship between subcarriers and superframes provided in an exemplary embodiment of this application;

[0078] Figure 22 is a schematic diagram of another relationship of superframes carried on four subcarriers provided in an exemplary embodiment of this application;

[0079] Figure 23 is a schematic diagram of a data transmission apparatus provided in an exemplary embodiment of this application;

[0080] Figure 24 is a schematic diagram of another structure of a data transmission apparatus provided in an exemplary embodiment of this application;

[0081] Figure 25 is a schematic diagram of the structure of an optical module provided in an exemplary embodiment of this application;

[0082] Figure 26 is a schematic diagram of a transmitting device provided in an exemplary embodiment of this application;

[0083] Figure 27 is a schematic diagram of another structure of the receiving device provided in an exemplary embodiment of this application. Detailed Implementation

[0084] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0085] This application provides a data transmission method, apparatus, device, and system, and presents a framing scheme for multi-subcarrier transmission. This scheme is beneficial for improving the quality of the recovered signal at the receiving end, has good phase noise tolerance, and is well compatible with framing schemes of 400ZR+ (an optical communication transmission applied to metropolitan areas), 800ZR, and 800ZR+. It is also beneficial for hardware implementation and can be well applied to various coherent transmission scenarios in the future.

[0086] This application provides a communication system, which can be an optical communication system such as a metropolitan area telecommunications transmission system or a metropolitan area data center interconnection (DCI) system, and the communication system can be a coherent optical communication system.

[0087] The communication system includes a transmitter and a receiver, which establish a communication connection through a channel. Both the transmitter and receiver can be communication devices (such as routers, optical transmission devices (such as optical line terminals (OLTs) or optical network terminals (ONTs)).

[0088] The channel can be a wired channel, such as an optical fiber.

[0089] Taking an example where both the transmitter and receiver are optical modules in a communication device, the transmitter can send signals to the receiver via a channel, enabling communication between them. For instance, the transmitter can process a bit sequence to obtain a superframe, and then send an optical signal to the channel based on this superframe. The receiver can receive the optical signal sent by the transmitter from the channel, recover the superframe from the optical signal, and process the superframe to obtain the bit sequence. This receiving process is the reverse of the transmitting process.

[0090] 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 DSP processor for dual polarization symbol mapping and 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, and phase recovery 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.

[0091] It should be noted that in this embodiment, digital subcarrier multiplexing technology is considered. This technology divides an optical signal (also called a channel) into multiple digital subcarriers, each carrying different carrier transmission information. Compared to traditional single-carrier transmission, each subcarrier in digital subcarrier multiplexing has a narrower bandwidth, making it more robust to high-bandwidth-related channel losses (such as dispersion and jitter). Therefore, the encoded data is typically distributed into W data streams for framing, carried on W subcarriers, and multiplexed to obtain a single signal for transmission. In this case, the baud rate corresponding to each subcarrier is 1 / W of the transmitted signal baud rate. The digital subcarrier implementation reduces the complexity of dispersion compensation and the overhead of enhanced equalization phase noise (EEPN), resulting in lower DSP power consumption. Optionally, W is an even number, and can be 2 or 4, etc.

[0092] Figure 2 is a schematic diagram of one embodiment of dual-polarization symbol mapping and framing in this application. As shown in Figure 2, in one possible embodiment, 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 includes, but is not limited to, QAM. Typically, QAM modulation (also known as symbol mapping) involves symbol mapping multiple input bits to obtain multiple QAM symbols, and polarization distribution of 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. It should be understood that symbol mapping usually uses Gray mapping, mapping multiple bits to one QAM symbol; in this case, 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 the following framing processing on a certain number of dual-polarization symbols: For example, it obtains a pre-framing dual-polarization symbol sequence (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 symbols and pilot symbols sequences to obtain the post-framing dual-polarization symbol sequence. Here, the inserted symbol sequence can also be called the preset symbol sequence. Among them, the frame synchronization symbol sequence includes frame synchronization symbols, the training symbol sequence includes training symbols (also known as the training sequence), the reserved symbol sequence includes reserved symbols, and the pilot symbol sequence includes pilot symbols (also known as the pilot sequence).

[0093] In this embodiment, the pre-framing dual-polarization symbol is also called the payload symbol, which includes FEC-encoded information and parity bits, mapped to obtain a symbol (called the information symbol and parity symbol). The post-framing dual-polarization symbol sequence is called a data frame, also known as a DSP 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. In some applications, certain reserved symbols can be used for feedback channel purposes. The values ​​of reserved symbols can be partially known and unchanging, or they can be randomized; the values ​​of reserved symbols can also be called a pattern.

[0094] In this embodiment, the data frame comprises multiple sub-frames. In some embodiments, the data frame is called a super-frame, and the frame synchronization symbol can also be called a super-frame alignment signal. In other embodiments, the data frame can also be called a multi-frame, the sub-frames are simply called frames, the reserved symbol can also be called fixed stuff (FS), and the frame synchronization symbol can also be called a multi-frame alignment signal (MFAS). A data frame comprising multiple sub-frames can also be referred to as "a super-frame comprising multiple sub-frames"; it can also be referred to as "a multi-frame comprising multiple frames."

[0095] In the embodiments of this application, the data frame is uniformly referred to as a superframe. It should be understood that in a superframe (also known as a DSP frame or multiple frames), the symbols remaining after removing the payload symbols (also known as pre-frame symbols), training symbols, pilot symbols, and frame synchronization symbols are called reserved symbols.

[0096] 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. As another example, a symbol obtained using QPSK modulation can be represented by any one of the following four complex numbers: ±1±1j. In some applications, the real and imaginary parts are normalized, but the essence remains unchanged.

[0097] In some applications, each training symbol and each pilot symbol is one of four complex numbers: -A-Aj, -A+Aj, A-Aj, and A+Aj, where A is a real number and j represents the imaginary unit. Here, Aj can also be written as A×j. 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. For example, for the 16QAM symbol mapping described above, A = 3 or -3 is selected to ensure good sensitivity of the training or pilot symbols. For QPSK symbol mapping, the four constellation points on the constellation diagram take values ​​of {±1±1j}, and A = 1 or -1 is selected.

[0098] In some other applications, each training symbol and each pilot symbol takes one of eight complex numbers, namely -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j, -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j, where A1 and A2 are non-zero real numbers, and the absolute value of A1 is less than the absolute value of A2, i.e., ∣A1∣ < ∣A2∣, and j represents the imaginary unit. The complex numbers -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j, -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j are the constellation points corresponding to the adopted symbol mapping. It should be noted that -A1 - A1j, -A1 + A1j, A1 - A1j, A1 + A1j can be expressed as (-1 - 1j)×A1, (-1 + 1j)×A1, (1 - 1j)×A1, (1 + 1j)×A1, and -A2 - A2j, -A2 + A2j, A2 - A2j, A2 + A2j can be expressed as (-1 - 1j)×A2, (-1 + 1j)×A2, (1 - 1j)×A2, (1 + 1j)×A2. Considering A1 < A2, it should be understood that the 4 constellation points corresponding to -A1 - A1j, -A1 + A1j, A1 - A1j, and A1 + A1j are the points in the inner circle of the constellation diagram, and the 4 constellation points corresponding to -A2 - A2j, -A2 + A2j, A2 - A2j, and A2 + A2j are the points in the outer circle of the constellation diagram. For example, taking the 16QAM symbol mapping as an example, there is A2 = 3×A1. The 16 constellation points (also called symbols) on the adopted 16QAM constellation diagram take values from {±1 ± 1j, ±1 ± 3j, ±3 ± 1j, ±3 ± 3j}, with A1 = 1 and A2 = 3. At this time, the 4 outermost constellation points in the constellation diagram are the symbols -3 - 3j, -3 + 3j, 3 - 3j, and 3 + 3j; the 4 innermost constellation points in the constellation diagram are the symbols -1 - 1j, -1 + 1j, 1 - 1j, and 1 + 1j. It should be noted that it is also possible to compress the symbols on the constellation diagram. Correspondingly, the values of A1 and A2 will also be compressed accordingly. For example, power normalization is performed on the 16 symbols with the same probability on the 16QAM constellation diagram. At this time, the values of the 16 symbols on the 16QAM constellation diagram become There is And When using the Probabilistic Constellation Shaping (PCS) processing technology, while keeping the positions of the constellation points unchanged, the probabilities of the constellation point symbols are changed to make them non-uniformly distributed, thereby improving the system transmission performance. At this time, the values of A1 and A2 are calculated according to the symbol probability distribution of the constellation, which will not be introduced here.

[0099] 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, to avoid 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.

[0100] 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.

[0101] It should also be noted that after dual-polarization symbol mapping and framing, a dual-polarization symbol 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 stream can also be represented by four data streams: the first is the data stream corresponding to the I-path component in the X-polarization direction (referred to as X...). I The second data stream is the data stream of the Q-path component in the X-polarization direction corresponding to the dual-polarization symbol stream (abbreviated as X). Q The third data stream is the data stream of the I-path component in the Y-polarization direction corresponding to the dual-polarization symbol stream (abbreviated as Y). I The fourth data stream is the data stream of the Q-path component in the Y-polarization direction corresponding to the dual-polarization symbol stream (abbreviated as Y). Q(Data flow).

[0102] It should be understood that in the dual-polarization symbol mapping and framing operations shown in Figure 2, 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.

[0103] Figure 3 is a schematic diagram of another implementation of the sending DSP processor in this application. As shown in Figure 3, framing is performed before dual-polarization symbol mapping. For example, 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 using the implementation shown in Figure 3 is the same as the post-framing dual-polarization symbol sequence obtained using the implementation shown in Figure 2.

[0104] Figure 4 is a schematic diagram of another embodiment of the transmitting DSP processor in this application. As shown in Figure 4, framing is performed before dual-polarization symbol mapping. For example, 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 4 is the same as the post-framing dual-polarization symbol sequence obtained by the embodiment shown in Figure 2.

[0105] Figure 5 is a schematic diagram of another embodiment of the originating DSP processor in this application. As shown in Figure 5, framing is performed before dual-polarization symbol mapping. For example, 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 method shown in Figure 5 before framing is the same as the framed dual-polarization symbol sequence obtained by using the implementation method shown in Figure 2.

[0106] It should be noted that this application does not limit the framing method adopted by the sending DSP processor. In addition to the framing methods described in Figures 2 to 5 above, other similar framing methods are also applicable to the embodiments of this application, and will not be described one by one here.

[0107] The following describes the process of data transmission.

[0108] Figure 6 is a schematic diagram of a data transmission method according to an embodiment of this application. As shown in Figure 6, the data transmission method includes steps S101 to S103.

[0109] Step S101: The transmitting end acquires W dual-polarization symbol streams, where W is an integer greater than 1.

[0110] In this embodiment, after the dual polarization symbol mapping and framing operation, the transmitting end obtains W dual polarization symbol streams to be sent. The dual polarization symbol stream can also be referred to as the dual polarization symbol data stream.

[0111] The W dual-polarization symbol streams are data streams transmitted in parallel. These streams include a first dual-polarization symbol stream and a second dual-polarization symbol stream. The first and second dual-polarization symbol streams are different; both streams include superframes. To distinguish between the superframes in the first and second dual-polarization symbol streams, the superframe in the first stream is referred to as the first superframe, and the superframe in the second stream is referred to as the second superframe. The first dual-polarization symbol stream includes one or more first superframes, and the second dual-polarization symbol stream includes one or more second superframes. The following describes one first superframe from the first dual-polarization symbol stream and one second superframe from the second dual-polarization symbol stream. From a temporal perspective, the first and second superframes are two superframes transmitted simultaneously in parallel.

[0112] It should be noted that a dual-polarization symbol stream consists of multiple superframes, and each superframe is a collection of multiple dual-polarization symbols. Multiple superframes constitute a dual-polarization symbol stream for transmission.

[0113] It should be noted that the embodiments of this application do not limit the implementation method of generating superframes. For example, the dual-polarization symbol mapping and framing method described in Figures 2 to 5 above can be used. Of course, other similar dual-polarization symbol mapping and framing methods are also applicable to the embodiments of this application, and will not be described one by one here. It should be understood that a superframe includes symbols in two polarization directions, that is, a superframe includes dual-polarization symbols. The structure of a superframe is similar in both polarization directions. For example, a superframe includes a symbol sequence in the X polarization direction and a symbol sequence in the Y polarization direction. The structure of a superframe will be described below using one polarization direction as an example.

[0114] Figure 7 is a schematic diagram of a superframe structure according to an embodiment of this application. As shown in Figure 7, the superframe includes N SF There are N subframes, each subframe comprising N S If there are N symbols, then the superframe includes N F A symbol, N F =N SF ×N S N S and N SF All are integers greater than 1. Subframes within a superframe are divided into two categories, referred to here as Category I subframes and Category II subframes. These two categories of subframes will be described separately below.

[0115] Figure 8 shows the N included in the embodiments of this application. SFA schematic diagram of the structure of a superframe with subframes. Figure 8(a) shows the structure of a first-type subframe, which includes training symbols, pilot symbols, frame synchronization symbols, reserved symbols, and payload symbols. Typically, the first-type subframe is the first subframe in the superframe, but it can also be located in other positions within the superframe, such as the last subframe. The other subframes in the superframe besides the first-type subframes are the second-type subframes, as shown in Figure 8(b). The second-type subframes differ from the first-type subframes in that they include training symbols, pilot symbols, and payload symbols, but do not include frame synchronization symbols and reserved symbols. It should be understood that the positions of the first-type and second-type subframes can also be changed; for example, the first-type subframe can be in the middle of the data or at the last position. This application does not impose any limitations on this.

[0116] For both Type I and Type II subframes, each subframe includes training symbols and pilot symbols. Training symbols are used for link training and / or subframe synchronization, while pilot symbols are used for carrier phase recovery. The number of training symbols in a subframe is denoted as N in any polarization direction. TS Let N be the number of pilot symbols in the subframe. PS N TS and N PS All are integers greater than 1. Optionally, one symbol in a subframe may be both a training symbol and a pilot symbol, i.e., the symbol indicated by the dashed box in Figure 8. For example, the first training symbol in the training sequence may be the first symbol in the pilot sequence. N TS The training symbols include the symbols indicated by the dashed box, N. PS Each pilot symbol also includes the symbol indicated by the dashed box. In some applications, N TS +N PS Greater than or equal to 5, and N TS +N PS It is an odd number.

[0117] Figure 8 shows a schematic diagram of a superframe structure, N TS N consecutive training symbols are arranged starting from the beginning position of the subframe. TS In a series of consecutive training symbols, the symbol at the beginning position is both a training symbol and a pilot symbol. That is, the first symbol of a subframe is the first symbol of both the training symbol sequence and 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 and the first symbol of the pilot symbol sequence have the same value.

[0118] In this embodiment of the application, in a superframe, the first symbol is described as the 1st symbol, that is, the sequence number starts from 1.

[0119] It should be noted that the frame synchronization symbols are used for synchronization between superframes. These frame synchronization symbols can be used for synchronization between superframes together with the training symbols, or can also be used to implement the synchronization function together with the pilot symbols. It should be understood that the frame synchronization symbols are arranged continuously and can be adjacent to the training symbols, as shown in FIG. 8 or FIG. 9. In addition, there can be one or more symbol intervals between the frame synchronization symbols and the training symbols. Additionally, the reserved symbols can be reserved for other future uses. The reserved symbols should be randomized and may not be the symbols on the constellation diagram of the modulation format used. Of course, in some applications, the reserved symbols can also be the symbols on the constellation diagram of the modulation format used. A part of the reserved symbols can also be fixed for other purposes, such as optical signal to noise ratio (OSNR) measurement, end-to-end (E2E) delay measurement, etc. The reserved symbols can also be located in one of multiple second-type subframes, and this application does not make any limitations. There is no overlap between the pilot symbols and the reserved symbols, nor is there any overlap between the pilot symbols and the payload symbols. That is to say, there are no symbols that are both pilot symbols and payload symbols, nor are there any symbols that are both pilot symbols and reserved symbols.

[0120] For each subframe in the superframe, every consecutive N PG symbols in the subframe include one pilot symbol located at a fixed position. N PG is a multiple of 32. For example, N PG = 32, 64, or 128. As shown in FIG. 8, N PG is 64. It should be understood that since the position of the pilot symbol in every consecutive N PG symbols is fixed, the intervals between two consecutive pilot symbols in the subframe are equal. As shown in FIG. 8, the pilot symbol is located at the starting position in every consecutive N PG symbols.

[0121] The embodiment of the present application also provides a schematic diagram of another structure of the superframe. As shown in FIG. 9, in another superframe, the first symbol in the pilot symbol sequence in any subframe is the ((N PG / W) × a + 1)-th symbol in the subframe, and the pilot symbol is the ((N PG / W) × a + 1)-th symbol in every consecutive N PG symbols, where the integer a satisfies 0 < a < W. In some embodiments, W = 2, and the first symbol in the pilot symbol sequence is the ((N PG / 2) + 1)-th symbol in every consecutive N PG symbols. For example, the first symbol in the pilot symbol sequence shown in FIG. 9 is the ((N PG=The 33rd symbol out of 64 symbols. In other implementations, W=4, and the first symbol in the pilot symbol sequence is every consecutive N. PG The (N)th symbol in the symbol PG / 4)+1 symbols, the (N)th symbol PG / 2)+1 symbols, or the (N)th symbol PG (×3 / 4)+1 symbols, for example, the first symbol in the pilot symbol sequence is every consecutive N PG = The 17th, 33rd, or 49th symbol out of 64 symbols.

[0122] According to the two superframe structures in Figures 7 and 8, in the first superframe, the i-th pilot symbol of each subframe is the i-th group of consecutive N-characters. PG The j-th symbol in the set of symbols, in the second superframe, the i-th pilot symbol of each subframe is the i-th group of consecutive N symbols. PG The (j+m)th symbol in a set of symbols, where j and m are positive integers, and j+m is less than or equal to N. PG In other words, in the first superframe, the i-th pilot symbol of each subframe is located in the i-th group of consecutive N... PG The j-th symbol position in the N symbols, in the second superframe, the i-th pilot symbol of each subframe is located in the i-th group of consecutive N symbols. PG The position of the (j+m)th symbol in a set of symbols. For example, in the first superframe, the first pilot symbol of the first subframe is the first group of consecutive N symbols. PG The j-th symbol in the set of symbols, in the second superframe, the first pilot symbol of the first subframe is the first group of consecutive N symbols. PG The (j+m)th symbol in the set of symbols, in the first superframe, the second pilot symbol of the first subframe is the second group of consecutive N symbols. PG The j-th symbol in the set of symbols, in the second superframe, the second pilot symbol of the first subframe is the second group of consecutive N symbols. PG The interval between the (j+m)th symbol in the first superframe and the second superframe is m symbols. Here, the first superframe and the second superframe are two superframes that are transmitted simultaneously in parallel.

[0123] It should be noted that in each subframe, the first symbol is called the first symbol of that subframe, in N PG When the value is 64, the first group of 64 consecutive symbols includes the first 64 symbols in the subframe, the second group of 64 consecutive symbols includes symbols 65 to 128 in the subframe, the third group of 64 consecutive symbols includes symbols 129 to 192 in the subframe, and so on, with the i-th group of 64 consecutive symbols including symbols (i-1)*64+1 to i*64 in the subframe. For example, in N PGThe number is 64, each subframe contains 7296 symbols, and each subframe contains 114 consecutive groups of 64 symbols.

[0124] Optionally, m and (N) PG / W)×a is related, 1≤a<W, where a is an integer.

[0125] Optionally, m is greater than or equal to 16.

[0126] Optionally, m is an even multiple of 16.

[0127] Optionally, m is an even multiple of 8.

[0128] Optionally, W is 2, N PG The value is 64, and m is 32.

[0129] Optionally, when W is 4, the W dual-polarization symbol streams include 4 dual-polarization symbol streams, which further include a third dual-polarization symbol stream and a fourth dual-polarization symbol stream. The third dual-polarization symbol stream includes a third superframe, and the fourth dual-polarization symbol stream includes a fourth superframe. In the third superframe, the i-th pilot symbol of each subframe is the i-th group of consecutive N... PG The (j+2m)th symbol in the set of symbols, in the fourth superframe, the i-th pilot symbol of each subframe is the i-th group of consecutive N symbols. PG The (j+3m)th symbol among the symbols, where both (j+2m) and (j+3m) are less than or equal to N. PG Thus, the symbol interval between the i-th pilot symbol of the second superframe and the i-th pilot symbol of the first superframe is m, the symbol interval between the i-th pilot symbol of the third superframe and the i-th pilot symbol of the second superframe is m, and the symbol interval between the i-th pilot symbol of the fourth superframe and the i-th pilot symbol of the third superframe is m. Here, the first, second, third, and fourth superframes are four superframes transmitted simultaneously in parallel.

[0130] Alternatively, when W is 4, N PG The value is 64, and m is 16.

[0131] Optionally, j is 1, meaning that in the first superframe, each pilot symbol is every consecutive N PG The first symbol among all the symbols (the first symbol).

[0132] Optionally, the W dual-polarization symbol streams are obtained by distributing one bit stream to obtain W distributed bit streams, which are then obtained by dual-polarization symbol mapping and framing.

[0133] In some applications, 16QAM symbol mapping is used, with the symbol values ​​of the 16 constellation points on the corresponding 16QAM constellation diagram being {±1±1j, ±1±3j, ±3±1j, ±3±3j}. As shown in the example of Figure 10(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, while vertical circle symbols are 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 (b) in Figure 10 shows a 16QAM symbol mapping method. 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.

[0134] Step S102: The transmitting end sends W dual-polarization symbol streams.

[0135] In this embodiment, the transmitting end carries W dual-polarization symbol streams on W subcarriers respectively, and then performs subcarrier multiplexing on the W subcarriers to obtain one signal, which is then transmitted by the transmitting end.

[0136] It should be noted that in W dual-polarization symbol streams, each stream is carried on one subcarrier, and the W streams are carried on W subcarriers, which typically use different wavelengths / frequencies. Each dual-polarization symbol stream can be considered to include at least one superframe, and the W streams can be considered to include at least W superframes, each carried on one of the W subcarriers. The W subcarriers are multiplexed to obtain a single signal for transmission. Subcarrier multiplexing is also known as digital subcarrier multiplexing (DSCM). Considering that each subcarrier uses a different frequency, subcarrier multiplexing is also called frequency division multiplexing (FDM), and the data transmission scheme is also called the DSCM scheme or the FDM scheme.

[0137] Step S103: The receiving end receives W dual-polarization symbol streams obtained through transmission and performs signal processing on the received W dual-polarization symbol streams.

[0138] In this embodiment, after receiving the optical signal, the receiving end processes the optical signal to obtain W dual-polarization symbol streams, and then performs signal processing on the W dual-polarization symbol streams as described in Figure 1.

[0139] It should be noted that the receiving end demultiplexes the received signal to obtain W received sub-signals, each corresponding to W subcarriers. Each of the W subcarriers contains multiple received superframes. The superframes received by the receiving end are those transmitted through the channel, which can be understood as distorted signals affected by noise or other impairments in the channel. That is to say, the superframes received by the receiving end are different from those transmitted by the transmitting end. For example, the superframes received by the receiving end and those transmitted by the transmitting end are not aligned. Moreover, one superframe corresponding to one subcarrier among the W subcarriers is not aligned with another superframe corresponding to another subcarrier. The receiving end needs to perform frame synchronization based on frame synchronization symbols or training symbols and perform deskew processing on the data between subcarriers to obtain the corresponding W transmitted superframes. The specific operations after the receiving end receives the superframes 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 superframes, including dispersion compensation, synchronization, and phase recovery.

[0140] To better understand the embodiments of this application, some examples are introduced below based on the superframes (also known as data frames, or multiframes, or DSP frames) provided in the embodiments of this application.

[0141] 1. W is 2.

[0142] Here, W is 2. Consider W = 2 superframes, where the 2 superframes are carried on 2 subcarriers respectively.

[0143] a、N PG =64, the total number of symbols N in any polarization direction in a superframe. F =87552.

[0144] In any polarization direction, consider the payload symbol (symbol before framing) in each superframe as N. CW=172032 / 2 = 86016 symbols. That is, each superframe contains 86016 dual-polarization payload symbols. These 86016 payload symbols are obtained through 16QAM modulation, i.e., 16QAM symbols. In some applications, these 86016 payload symbols are obtained through QPSK modulation, i.e., QPSK symbols. Consider the first and second superframes, where the first superframe is carried on one subcarrier and the second superframe is carried on another subcarrier. The first and second superframes together contain 172032 payload symbols, equal to the number of payload symbols in current 400ZR+, 800ZR, and 800ZR+ systems. It should be understood that the bit data corresponding to the payload symbols comes from data obtained through coding interleaving; that is, the framing scheme adopted is compatible with current 400ZR+, 800ZR, and 800ZR+ coding interleaving schemes, which is beneficial for hardware implementation.

[0145] As shown in Figure 11, for each superframe in the first and second superframes, each superframe includes N. SF = 12 subframes, and the total number of symbols N in one polarization direction F =87552. The number of pilot symbols N in each subframe along one polarization direction. PS =114, per N PG =The first symbol in the 64 symbols is the pilot symbol, and the number of training symbols N TS =11, each subframe contains a total of N S = 7296 symbols. Subframe 1 is the first subframe, and subframes 2 through 12 are the second to twelfth subframes. Table 1 shows some parameter combinations for the superframe (both the first and second superframes satisfy the conditions given in Table 1), including the number N of frame synchronization symbols in a superframe along a single polarization direction. FAW and the number of reserved symbols N RES In the embodiments of this application, the symbols remaining after removing the payload symbols, training symbols, pilot symbols, and frame synchronization symbols in a superframe can be referred to as reserved symbols.

[0146] Table 1

[0147] It should be understood that Table 1 above provides a variety of possible superframe schemes, where the number of frame synchronization symbols N FAW All numbers are even, effectively ensuring that the frame synchronization symbols can meet DC balance. Moreover, the relatively long number of frame synchronization symbols allows the receiving end to identify the position of the frame synchronization symbols better and more accurately during synchronization processing, making the transmission system more robust and reliable.

[0148] It should be noted that the number of symbols in this application can be understood as the number of dual-polarization symbols or the number of symbols in one polarization direction; moreover, the number of different symbols in both polarization directions is the same. For example, if there are 11 training symbols in one polarization direction, there are also 11 training symbols in the other polarization direction, resulting in 11 dual-polarization training symbols overall. Furthermore, the serial numbers in Table 1 are only used to distinguish different parameter combinations and do not constitute any other limitation. The following tables can be interpreted in the same way based on the above explanation, and this application will not repeat them further.

[0149] It should be understood that for a superframe using the parameter combinations in Table 1, the number of pilot symbols N PS =114, pilot spacing N PG =64, Number of training symbols N TS =11, each subframe includes N S =7296 symbols, all of which are equal to the parameters in the current 800ZR / 800ZR+ framing, which is well compatible with the current DSP framing scheme of 800ZR and 800ZR+ and facilitates hardware implementation.

[0150] It should be understood that when the superframe uses the parameter combination of number 7 in Table 1, the number of pilot symbols N PS =114, pilot spacing N PG =64, Number of training symbols N TS =11, each subframe contains a total of N S = 7296 symbols, number of frame synchronization symbols N FAW =22 are all equal to the parameters in the 800ZR / 800ZR+ framing, which is more compatible with the DSP framing scheme of 800ZR and 800ZR+ and is more conducive to hardware implementation.

[0151] In some applications, N TS =The 11 training symbols use the symbol sequence shown in Table 2.

[0152] Table 2

[0153] In some applications, N PS =The 114 pilot symbols are determined based on the generator polynomial and its corresponding seed. The generator polynomial is x 10 +x 7 +x 3 +x+1 corresponds to hexadecimal seeds of 0x34E and 0x084 in the two polarization directions. N PS The values ​​of the 114 pilot symbols are shown in Table 3.

[0154] Table 3

[0155] In some applications, consider N FAW =22, there are N RES =26. N FAW =The sequence of 22 frame synchronization symbols adopts the symbol sequence shown in Table 4.

[0156] Table 4

[0157] In one alternative approach, as shown in Figure 12, consider W = 2 subcarriers, namely subcarrier 1 and subcarrier 2. Each subcarrier carries multiple superframes. Each superframe in subcarrier 1 (or subcarrier 2) uses the same frame format, i.e., the same parameter combination. This embodiment uses the parameter combination specified in number 7 of Table 1 as an example for illustration.

[0158] The structure of subframe 1 in the first superframe carried by subcarrier 1 is shown in Figure 12(a). Eleven training symbols are located at symbol positions 1-11 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 26 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Furthermore, the structure of any subframe from subframe 2 to subframe 12 is shown in Figure 12(b). Eleven training symbols are located at symbol positions 1-11 in the subframe, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0159] The structure of subframe 1 in the second superframe carried by subcarrier 2 is shown in Figure 12(c). Eleven training symbols are located at symbol positions 33-43 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 26 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Furthermore, the structure of any subframe from subframe 2 to subframe 12 is shown in Figure 12(d). Eleven training symbols are located at symbol positions 33-43 in the subframe, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0160] The total number of symbols N in the first superframe (or the second superframe) F =87552, Number of load symbols N CW =86016, Number of frame synchronization symbols N FAW =22, retain the number of signs N RES=26, number of subframes N SF =12; each subframe includes a total of N S = 7296 symbols, number of pilot symbols N PS =114, pilot spacing N PG =64, Number of training symbols N TS =11. It should be understood that in the embodiments of this application, the number of symbols refers to the number of symbols in any polarization direction, and also refers to the number of dual-polarization symbols.

[0161] N TS = 11 training symbols were used, following the symbol sequence shown in Table 2. N PS =The 114 pilot symbols are determined based on the generator polynomial and its corresponding seed. The generator polynomial is x 10 +x 7 +x 3 +x+1 corresponds to hexadecimal seeds of 0x34E and 0x084 in the two polarization directions. N PS The values ​​of the 114 pilot symbols are shown in Table 3. FAW =The sequence of 22 frame synchronization symbols adopts the symbol sequence shown in Table 4.

[0162] It should be understood that the number of pilot symbols N PS =114, pilot spacing N PG =64, Number of training symbols N TS =11, each subframe includes a total of N S = 7296 symbols, number of frame synchronization symbols N FAW =22 are all equal to the parameters in 800ZR / 800ZR+ framing, which is more compatible with the DSP framing schemes of 800ZR and 800ZR+, and is more conducive to hardware implementation. Moreover, N TS =The symbol sequence of the 11 training symbols is the same as the training symbol sequences of 400ZR+, 800ZR, and 800ZR+, N PS =The symbol sequence of the 114 pilot symbols is the same as that of the pilot symbols of 400ZR+, 800ZR, and 800ZR+, N FAW =The symbol sequence of the 22 frame synchronization symbols is the same as that of the frame synchronization symbol sequence of 400ZR+, 800ZR, and 800ZR+, which is more compatible with the DSP framing scheme of 400ZR+, 800ZR, and 800ZR+ and is more conducive to hardware implementation.

[0163] Furthermore, as shown in Figure 12, the interval between the first pilot symbol of the first subframe in the first superframe and the first pilot symbol of the first subframe in the second superframe is 32; the interval between the second pilot symbol of the first subframe in the first superframe and the second pilot symbol of the first subframe in the second superframe is 32; the interval between the first pilot symbol of the second subframe in the first superframe and the first pilot symbol of the second subframe in the second superframe is 32, and so on. Considering that the two superframes are transmitted in parallel in the time dimension, the equivalent number of pilot symbol intervals for this multi-carrier transmission scheme is 32, which is less than N in the traditional DSP framing scheme. PG =64. When the receiver performs joint subcarrier recovery processing, the pilot symbol spacing used for carrier phase recovery processing can be considered to be halved from the traditional 64 symbols to 32 symbols, further improving anti-dispersion capability and phase noise tolerance. The superframe scheme provided in this application can be applied to future scenarios using multi-subcarrier transmission. For example, 800Gbps multi-subcarrier transmission using QPSK modulation, 1.2Tbps multi-subcarrier transmission using 16QAM modulation, 1.6Tbps multi-subcarrier transmission using 16QAM modulation, and even higher speed transmission scenarios such as 2.4T / 3.2T.

[0164] In another alternative approach, consider that the 22 frame synchronization symbols in a superframe are located at the end of any subframe within that superframe. The positions of these frame synchronization symbols can be the same or different in superframes from different dual-polarization symbol streams. For example, the frame synchronization symbol of the first superframe might be located at the end of the last subframe, while the frame synchronization symbol of the second superframe might be located at the end of the penultimate subframe. Alternatively, the 22 frame synchronization symbols in each superframe could be located at the end of the last subframe within that superframe. In other words, considering that the 22 frame synchronization symbols of the first and second superframes are both located in the last 22 symbols of their respective superframes ensures a consistent frame synchronization symbol implementation at the receiver, facilitating hardware implementation.

[0165] Optionally, superframes belonging to the same dual-polarization symbol stream have the same frame synchronization position.

[0166] Optionally, in any polarization direction, in a superframe, the reserved symbol (i.e., the symbol in the superframe other than the training symbol, pilot symbol, payload symbol and frame synchronization symbol) is located after the training symbol in the first type of subframe and adjacent to the training symbol in the first type of subframe.

[0167] For example, the structure of subframe 1 in the first superframe carried by subcarrier 1 is shown in Figure 13(a), where 11 training symbols are located at symbol positions 1-11 in subframe 1, and 26 reserved symbols are located after and adjacent to the aforementioned 11 training symbols. The first training symbol among the aforementioned 11 training symbols is also the first pilot symbol among the 114 pilot symbols. Similarly, the structure of subframes 2-12 is shown in Figure 13(b), where 11 training symbols are located at symbol positions 1-11 in the subframes, and the first training symbol among the aforementioned 11 training symbols is also the first pilot symbol among the 114 pilot symbols.

[0168] The structure of subframe 1 in the second superframe carried by subcarrier 2 is shown in Figure 13(c). Eleven training symbols are located at symbol positions 33-43 in subframe 1, and 26 reserved symbols are located after and adjacent to these eleven training symbols. The first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Furthermore, the structure of subframes 2-12 is shown in Figure 13(d). Eleven training symbols are located at symbol positions 33-43 in these subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0169] The structure shown in Figure 13 enables the superframe to have better anti-dispersion capability and better phase noise tolerance, making it suitable for future scenarios using multi-subcarrier transmission, such as 800Gbps multi-subcarrier transmission using QPSK modulation, 1.2Tbps multi-subcarrier transmission using 16QAM modulation, 1.6Tbps multi-subcarrier transmission using 16QAM modulation, and even higher speed transmission scenarios such as 2.4T / 3.2T.

[0170] In another alternative approach, within a polarization direction, reserved symbols can also be located later in the superframe. For example, 26 reserved symbols are located before and adjacent to the frame synchronization symbol. Here, "adjacent" can be understood as the presence of a symbol adjacent to the frame synchronization symbol among the 26 reserved symbols. Due to the presence of pilot symbols, the positions of the reserved symbols are separated by one pilot symbol, as shown in (a) to (d) of Figure 14.

[0171] It should be noted that the position of the reserved symbol can be set according to actual needs, and this application embodiment does not limit it.

[0172] b、N PG =64, the total number of symbols N in any polarization direction in a superframe. F =175104.

[0173] As shown in Figure 15, consider W = 2 subcarriers, namely subcarrier 1 and subcarrier 2. Each subcarrier carries multiple superframes. Each superframe in subcarrier 1 (or subcarrier 2) uses the same frame format, that is, the same combination of parameters.

[0174] In any polarization direction, the total number of symbols N in the first superframe (or the second superframe) F =175104, Number of load symbols N CW =172032, number of frame synchronization symbols N FAW =22, retain the number of signs N RES =74, number of subframes N SF =24; each subframe contains a total of N S = 7296 symbols, number of pilot symbols N PS =114, pilot spacing N PG =64, Number of training symbols N TS =11. It should be understood that in the embodiments of this application, the number of symbols refers to the number of symbols in any polarization direction, and also refers to the number of dual-polarization symbols.

[0175] In one alternative approach, the structure of subframe 1 in the first superframe carried by subcarrier 1 is shown in Figure 16(a), wherein 11 training symbols are located at symbol positions 1-11 in subframe 1, 22 frame synchronization symbols are located after the aforementioned 11 training symbols, and 74 reserved symbols are located after and adjacent to the aforementioned 22 frame synchronization symbols. The first training symbol among the aforementioned 11 training symbols is also the first pilot symbol among the 114 pilot symbols. Furthermore, the structure of subframes 2-24 is shown in Figure 16(b), wherein 11 training symbols are located at symbol positions 1-11 in the subframes, and the first training symbol among the aforementioned 11 training symbols is also the first pilot symbol among the 114 pilot symbols.

[0176] The structure of subframe 1 in the second superframe carried by subcarrier 2 is shown in Figure 16(c). Eleven training symbols are located at symbol positions 33-43 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 74 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Furthermore, the structure of subframes 2-24 is shown in Figure 16(d). Eleven training symbols are located at symbol positions 33-43 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0177] N TS= 11 training symbols were used, following the symbol sequence shown in Table 2. N PS =The 114 pilot symbols are determined based on the generator polynomial and its corresponding seed. The generator polynomial is x 10 +x 7 +x 3 +x+1 corresponds to hexadecimal seeds of 0x34E and 0x084 in the two polarization directions. N PS The values ​​of the 114 pilot symbols are shown in Table 3. FAW =The sequence of 22 frame synchronization symbols adopts the symbol sequence shown in Table 4.

[0178] It should be understood that the framing scheme of the first or second superframe is completely consistent with the current DSP framing scheme of 800ZR and 800ZR+, has good compatibility, and is more conducive to hardware implementation.

[0179] Furthermore, as can be seen from Figure 16, the interval between the first pilot symbol in the first superframe and the first pilot symbol in the second superframe is 32, which is smaller than the traditional N. PG =64. When the receiver performs joint subcarrier recovery processing, the pilot symbol spacing used for carrier phase recovery processing can be considered to be halved from the traditional 64 symbols to 32 symbols, further improving anti-dispersion capability and phase noise tolerance. The superframe scheme provided in this implementation can be applied to future scenarios using multi-subcarrier transmission, such as 800Gbps multi-subcarrier transmission using QPSK modulation, 1.2Tbps multi-subcarrier transmission using 16QAM modulation, 1.6Tbps multi-subcarrier transmission using 16QAM modulation, and even higher speed transmission scenarios such as 2.4T / 3.2T.

[0180] In another alternative approach, consider that the 22 frame synchronization symbols in the superframe are located at the end of any subframe within that superframe. For example, the 22 frame synchronization symbols in the superframe may be located at the end of the last subframe within that superframe. In other words, consider that the 22 frame synchronization symbols of the first superframe and the 22 frame synchronization symbols of the second superframe are both located in the last 22 symbol positions of their respective superframes. This ensures that the frame synchronization symbol implementation scheme at the receiver is consistent, facilitating hardware implementation.

[0181] The structure of subframe 1 in the first superframe carried by subcarrier 1 is shown in Figure 17(a). Eleven training symbols are located at symbol positions 1-11 in subframe 1, and 74 reserved symbols are located after and adjacent to these eleven training symbols. The first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols. The 74 reserved symbols are divided into two parts by a single pilot symbol. Furthermore, the structure of subframes 2-24 is shown in Figure 17(b). Eleven training symbols are located at symbol positions 1-11 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0182] The structure of subframe 1 in the second superframe carried by subcarrier 2 is shown in Figure 17(c). Eleven training symbols are located at symbol positions 33-43 in subframe 1, and 74 reserved symbols are located after and adjacent to these eleven training symbols. The first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols. The 74 reserved symbols are divided into two parts by a single pilot symbol. Furthermore, the structure of subframes 2-24 is shown in Figure 17(d). Eleven training symbols are located at symbol positions 33-43 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0183] The superframe solution provided in this implementation has good anti-dispersion capability and better phase noise tolerance. It can be applied to future scenarios that use multi-subcarrier transmission, such as 800Gbps multi-subcarrier transmission using QPSK modulation, 1.2Tbps multi-subcarrier transmission using 16QAM modulation, 1.6Tbps multi-subcarrier transmission using 16QAM modulation, and even higher speed transmission scenarios such as 2.4T / 3.2T.

[0184] In another alternative approach, the reserved symbols can also be located later in the superframe. For example, 74 reserved symbols are located before and adjacent to the frame synchronization symbol. Here, "adjacent" can be understood as the presence of a symbol adjacent to the frame synchronization symbol among the 74 reserved symbols. Due to the presence of pilot symbols, the positions of the reserved symbols are separated by one pilot symbol, as shown in Figures 18(a) to (d). The description of the training symbols in Figure 18 is shown in Figure 17.

[0185] 2. W is 4.

[0186] Here, W is 4. Consider W = 4 superframes, where the 4 superframes are carried on 4 subcarriers respectively.

[0187] The first symbol in the pilot symbol sequence is every consecutive NPG The (N)th symbol in the symbol PG / 4)+1 symbols, the (N)th symbol PG / 2)+1 symbol or the (N)th symbol PG (×3 / 4)+1 symbols, for example, the first symbol in the pilot symbol sequence is every consecutive N PG = The 17th, 33rd, or 49th symbol out of 64 symbols.

[0188] Consider W = 4 superframes, N PG The number of superframes is 64, representing the first, second, third, and fourth superframes. For the first superframe, the first pilot symbol in each subframe is the 1st symbol of that subframe. For the second superframe, the first pilot symbol in each subframe is the 17th symbol of that subframe. For the third superframe, the first pilot symbol in each subframe is the 33rd symbol of that subframe. For the fourth superframe, the first pilot symbol in each subframe is the 49th symbol of that subframe.

[0189] a、N PG =64, the total number of symbols N in any polarization direction in a superframe. F =87552.

[0190] In any polarization direction, consider the payload symbol (pre-framing symbol) in each superframe as N. CW = 86016 symbols. In some applications, the 86016 payload symbols are obtained through 16QAM modulation, i.e., 16QAM symbols. In other applications, the 86016 payload symbols are obtained through QPSK modulation, i.e., QPSK symbols. Each of the four superframes contains N. SF = 12 subframes, and the total number of symbols N in one polarization direction F =87552. The number of pilot symbols N in each subframe along one polarization direction. PS =114, per N PG =The first symbol in the 64 symbols is the pilot symbol, and the number of training symbols N TS =11, each subframe contains a total of N S = 7296 symbols. The parameters for each of the four superframes are given in Table 1 (one row). Furthermore, the number of frame synchronization symbols N in the superframe... FAW =22 and the number of reserved symbols N RES =26.

[0191] Optionally, as shown in Figures 19(a) and (b), consider W = 4 subcarriers, namely subcarrier 1, subcarrier 2, subcarrier 3, and subcarrier 4. Subcarrier 1 carries multiple first superframes, subcarrier 2 carries multiple second superframes, subcarrier 3 carries multiple third superframes, and subcarrier 4 carries multiple fourth superframes. Each superframe in subcarrier 1 (or subcarrier 2, or subcarrier 3, or subcarrier 4) uses the same frame format.

[0192] The total number of symbols N in the first (or second, third, or fourth) superframe F =87552, Number of load symbols N CW =86016, Number of frame synchronization symbols N FAW =22, retain the number of signs N RES =26, number of subframes N SF =12; each subframe contains a total of N S = 7296 symbols, number of pilot symbols N PS =114, pilot spacing N PG =64, Number of training symbols N TS =11.

[0193] The structure of subframe 1 in the first superframe carried by subcarrier 1 is shown in Figure 20(a). Eleven training symbols are located at symbol positions 1-11 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 26 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Similarly, the structures of subframes 2-12 are shown in Figure 20(b). Eleven training symbols are located at symbol positions 1-11 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0194] The structure of subframe 1 in the second superframe carried by subcarrier 2 is shown in Figure 20(c). Eleven training symbols are located at symbol positions 20-27 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 26 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Furthermore, the structure of subframes 2-12 is shown in Figure 20(d). Eleven training symbols are located at symbol positions 17-27 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0195] The structure of subframe 1 in the third superframe carried by subcarrier 3 is shown in Figure 20(e). Eleven training symbols are located at symbol positions 33-43 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 26 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Similarly, the structure of subframes 2-12 is shown in Figure 20(f). Eleven training symbols are located at symbol positions 33-43 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0196] The structure of subframe 1 in the fourth superframe carried by subcarrier 4 is shown in Figure 20(g). Eleven training symbols are located at symbol positions 49-59 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 26 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Similarly, the structure of subframes 2-12 is shown in Figure 20(h). Eleven training symbols are located at symbol positions 49-59 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0197] N TS = 11 training symbols were used, following the symbol sequence shown in Table 2. N PS =The 114 pilot symbols are determined based on the generator polynomial and its corresponding seed. The generator polynomial is x 10 +x 7 +x 3 +x+1 corresponds to hexadecimal seeds of 0x34E and 0x084 in the two polarization directions. N PS The values ​​of the 114 pilot symbols are shown in Table 3. FAW =The sequence of 22 frame synchronization symbols adopts the symbol sequence shown in Table 4.

[0198] It should be understood that the framing schemes for the first, second, third, or fourth superframes are similar to the current DSP framing schemes for the 800ZR and 800ZR+, have good compatibility, and are more conducive to hardware implementation.

[0199] Furthermore, as shown in Figure 20, the interval between the first pilot symbol in the first superframe and the first pilot symbol in the second superframe is 16, the interval between the first pilot symbol in the second superframe and the first pilot symbol in the third superframe is 16, and the interval between the first pilot symbol in the third superframe and the first pilot symbol in the fourth superframe is 16. Considering that the four superframes are transmitted in parallel in the time dimension, the equivalent number of pilot symbol intervals in this multi-carrier transmission scheme is 16, which is less than N in the traditional DSP framing scheme. PG =64. When the receiver performs joint subcarrier recovery processing, the pilot symbol spacing used for carrier phase recovery processing can be considered to be reduced from the traditional 64 symbols to one-quarter, or 16 symbols, further improving anti-dispersion capability and phase noise tolerance. The superframe scheme provided in this implementation can be applied to future scenarios using multi-subcarrier transmission, such as 800Gbps multi-subcarrier transmission using QPSK modulation, 1.2Tbps multi-subcarrier transmission using 16QAM modulation, 1.6Tbps multi-subcarrier transmission using 16QAM modulation, and even higher speeds such as 2.4T / 3.2T transmission scenarios.

[0200] b、N PG =64, the total number of symbols N in any polarization direction in a superframe. F =175104.

[0201] In any polarization direction, consider the payload symbol N in each superframe. CW = 172032 symbols. In some applications, the 172032 payload symbols are obtained through 16QAM modulation, i.e., 16QAM symbols. In other applications, the 172032 payload symbols are obtained through QPSK modulation, i.e., QPSK symbols. Each of the four superframes contains N. SF = 24 subframes, and the total number of symbols N in one polarization direction F =175104. The number of pilot symbols N in each subframe along one polarization direction. PS =114, per N PG =The first symbol in the 64 symbols is the pilot symbol, and the number of training symbols N TS =11, each subframe contains a total of N S = 7296 symbols. Furthermore, the number N of frame synchronization symbols in a superframe... FAW =22 and the number of reserved symbols N RES =74.

[0202] Optionally, as shown in Figures 21(a) and (b), consider W = 4 subcarriers, namely subcarrier 1, subcarrier 2, subcarrier 3, and subcarrier 4. Subcarrier 1 carries multiple first superframes, subcarrier 2 carries multiple second superframes, subcarrier 3 carries multiple third superframes, and subcarrier 4 carries multiple fourth superframes. Each superframe in subcarrier 1 (or subcarrier 2, or subcarrier 3, or subcarrier 4) uses the same frame format.

[0203] The total number of symbols N in the first (or second, third, or fourth) superframe F =175104, Number of load symbols N CW =172032, number of frame synchronization symbols N FAW =22, retain the number of signs N RES =74, number of subframes N SF =24; each subframe contains a total of N S = 7296 symbols, number of pilot symbols N PS =114, pilot spacing N PG =64, Number of training symbols N TS =11.

[0204] The structure of subframe 1 in the first superframe carried by subcarrier 1 is shown in Figure 22(a). Eleven training symbols are located at symbol positions 1-11 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 74 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Similarly, the structure of subframes 2-24 is shown in Figure 22(b). Eleven training symbols are located at symbol positions 1-11 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0205] The structure of subframe 1 in the second superframe carried by subcarrier 2 is shown in Figure 22(c). Eleven training symbols are located at symbol positions 17-27 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 74 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Furthermore, the structure of subframes 2-24 is shown in Figure 22(d). Eleven training symbols are located at symbol positions 17-27 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0206] The structure of subframe 1 in the third superframe carried by subcarrier 3 is shown in Figure 22(e). Eleven training symbols are located at symbol positions 33-43 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 74 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Similarly, the structure of subframes 2-24 is shown in Figure 22(f). Eleven training symbols are located at symbol positions 33-43 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0207] The structure of subframe 1 in the fourth superframe carried by subcarrier 4 is shown in Figure 22(g). Eleven training symbols are located at symbol positions 49-59 in subframe 1, 22 frame synchronization symbols are located after and adjacent to these eleven training symbols, and 74 reserved symbols are located after and adjacent to these 22 frame synchronization symbols. The first training symbol among the eleven training symbols is also the first pilot symbol among the 114 pilot symbols. Similarly, the structure of subframes 2-24 is shown in Figure 22(h). Eleven training symbols are located at symbol positions 49-59 in the subframes, and the first training symbol among these eleven training symbols is also the first pilot symbol among the 114 pilot symbols.

[0208] N TS = 11 training symbols were used, following the symbol sequence shown in Table 2. N PS =The 114 pilot symbols are determined based on the generator polynomial and its corresponding seed. The generator polynomial is x 10 +x 7 +x 3 +x+1 corresponds to hexadecimal seeds of 0x34E and 0x084 in the two polarization directions. N PS The values ​​of the 114 pilot symbols are shown in Table 3. FAW =The sequence of 22 frame synchronization symbols adopts the symbol sequence shown in Table 4.

[0209] It should be understood that the framing schemes for the first, second, third, or fourth superframes are the same as those for the current DSP framing schemes of the 800ZR and 800ZR+, which have good compatibility and are more conducive to hardware implementation.

[0210] Furthermore, as shown in Figure 22, the interval between the first pilot symbol in the first superframe and the first pilot symbol in the second superframe is 16, the interval between the first pilot symbol in the second superframe and the first pilot symbol in the third superframe is 16, and the interval between the first pilot symbol in the third superframe and the first pilot symbol in the fourth superframe is 16. Considering that the four superframes are transmitted in parallel in the time dimension, the equivalent number of pilot symbol intervals in this multi-carrier transmission scheme is 16, which is less than N in the traditional DSP framing scheme. PG =64. When the receiver performs joint subcarrier recovery processing, the pilot symbol spacing used for carrier phase recovery processing can be considered to be reduced from the traditional 64 symbols to one-quarter, i.e., 16 symbols, further improving anti-dispersion capability and phase noise tolerance. The superframe scheme provided in this implementation can be applied to future scenarios using multi-subcarrier transmission, such as 800Gbps multi-subcarrier transmission using QPSK modulation, 1.2Tbps multi-subcarrier transmission using 16QAM modulation, 1.6Tbps multi-subcarrier transmission using 16QAM modulation, and even higher speed transmission scenarios such as 2.4T / 3.2T.

[0211] In an alternative approach, when W is 4, the frame synchronization symbol can also be located at the end of any subframe within the superframe, regardless of the polarization direction. The case of W=4 is the same as the case of W=2, and will only be briefly described here. For example, the frame synchronization symbol is located at the end of the last subframe within the superframe.

[0212] Optionally, if the frame synchronization symbol is located at the end of the last subframe in the superframe, the reserved symbol can be after the training symbol and adjacent to the training symbol.

[0213] Optionally, if the frame synchronization symbol is located at the end of the last subframe in the superframe, the reserved symbol may be located before and adjacent to the frame synchronization symbol.

[0214] It should be noted that in the embodiments of this application, the example of using the first symbol of the training sequence as the first symbol of the pilot sequence in a subframe is used for illustration. In other implementations, the symbols of the training sequence and the pilot sequence are not reused.

[0215] It should also be noted that, in the embodiments of this application, in a superframe, the training symbol and the frame synchronization symbol are adjacent; in other embodiments, other symbols may exist between the training symbol and the frame synchronization symbol. In a superframe, the reserved symbol and the frame synchronization symbol are adjacent; in other embodiments, other symbols may exist between the reserved symbol and the frame synchronization symbol.

[0216] Figure 23 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 23, the data transmission device includes a processing unit 201 and a transmitting unit 202. The processing unit 201 is used to perform the action of acquiring W dual-polarization symbol streams in the above embodiment; the transmitting unit 202 is used to perform the action of transmitting W dual-polarization symbol streams in the above embodiment. Specific implementation methods have been described in previous embodiments and will not be repeated here.

[0217] Figure 24 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 24, the data transmission device includes a receiving unit 302, which receives W dual-polarized symbol streams transmitted through the channel. These W dual-polarized symbol streams are consistent with the W dual-polarized symbol streams in the transmitting 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.

[0218] It should be understood that the data transmission devices provided in Figures 23 and 24 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.

[0219] Figure 25 is a schematic diagram of an optical module structure according to an embodiment of this application. As shown in Figure 25, 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.

[0220] In one possible scenario, the optical module is used at the transmitting end, and the processor 401 is used to acquire a superframe including multiple subframes, and to generate multiple pilot symbols included in the subframes based on the generator 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 FIG23. As an example, the processor 401 performs the operations in the above embodiments to obtain W dual-polarization symbol streams, and sends the W dual-polarization symbol streams 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 W dual-polarization symbol streams, and the modulator in the optical module performs electro-optic conversion and other signal processing according to the W dual-polarization symbol streams 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.

[0221] 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 24. 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 superframe. The processor 401 performs the operations described in the above embodiments on this superframe. 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 W dual-polarization symbol streams, and transmits these W dual-polarization symbol streams to the processor 401 through the interface 402. The processor 401 performs the operations described in the above embodiments on these W dual-polarization symbol streams. In this example, the interface 402 specifically refers to an electrical interface.

[0222] 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.

[0223] 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.

[0224] Figure 26 is a schematic diagram of a transmitting device according to an embodiment of this application. As shown in Figure 26, 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 a channel. For example, the host-side device 501 can be a switch, router, or server. The transmitting device can be a communication device including the host-side device 501 and the optical module 502. It should also be understood that the transmitting devices in this embodiment are named based on the data flow direction and do not limit the function of the device. For example, the transmitting device can also have a receiving function.

[0225] Figure 27 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 can 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 can also have a sending function.

[0226] This application also provides an Optical Transport Network (OTN) device, which includes line-side equipment and client-side equipment. The client-side equipment may also be referred to as a tributary-side equipment in some scenarios. The line-side equipment includes a processor and an interface. In one possible scenario, the OTN device is used at the transmitting end, and the processor is used to execute the operation of step 101 in the above embodiment. In another possible scenario, the OTN device is used at the receiving end, and the processor is used to execute the operation of step 103 in the above embodiment. The interface can be a transceiver or an input / output interface, used to receive signals from other devices besides the line-side equipment and transmit them to the processor, or to send signals from the processor to other devices besides the line-side equipment.

[0227] 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.

[0228] 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.

[0229] 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.

[0230] 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.

[0231] As an example, the processor in the embodiments of this application can be a CPU, or other general-purpose processors, DSPs, ASICs, 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.

[0232] 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 communication device or terminal device. Alternatively, the processor and storage medium may exist as discrete components in the communication device or terminal device.

[0233] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof.

[0234] 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.

[0235] 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).

[0236] The terms "first" and "second," etc., used in this specification and the accompanying drawings are used to distinguish similar objects and 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 herein can be implemented in a sequence other than that described herein. 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 apparatus 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 such processes, methods, products, or apparatus.

[0237] Finally, it should be noted that the above are merely exemplary 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 scope of the technology 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

A method for data transmission, characterized in that, The method includes: W dual-polarization symbol streams are sent, wherein the first dual-polarization symbol stream includes a first superframe, and the second dual-polarization symbol stream includes a second superframe; in any polarization direction, every consecutive N subframes of the first superframe and the second superframe... PG Each symbol includes a pilot symbol, and the i-th pilot symbol of each subframe of the first superframe is the i-th group of consecutive N symbols. PG The j-th symbol in the N symbols, and the i-th pilot symbol in each subframe of the second superframe is the i-th group of consecutive N symbols. PG The (j+m)th symbol in the set of symbols, W is greater than 1, i is greater than or equal to 1, j and m are both positive integers, and j+m is less than or equal to N. PG . The method according to claim 1, characterized in that, m and (N) PG / W)×a is related, 1≤a<W, where a is an integer. The method according to claim 1, characterized in that, m is greater than or equal to 16. The method according to claim 3, characterized in that, W is 2, N PG The value is 64, and m is 32. The method according to any one of claims 1 to 3, characterized in that, When W is 4, the third dual-polarization symbol stream in the W dual-polarization symbol streams includes a third superframe, and the fourth dual-polarization symbol stream includes a fourth superframe; in any polarization direction, every consecutive N in each subframe of the third superframe and the fourth superframe PG Each symbol includes a pilot symbol, and the i-th pilot symbol of each subframe of the third superframe is the i-th group of consecutive N symbols. PG The (j+2m)th symbol in the set of symbols, and the i-th pilot symbol of each subframe of the fourth superframe is the i-th group of consecutive N symbols. PG The (j+3m)th symbol among the symbols, where both (j+2m) and (j+3m) are less than or equal to N. PG . The method according to claim 5, characterized in that, N PG The value is 64, and m is 16. The method according to any one of claims 1 to 6, characterized in that, j is 1. The method according to any one of claims 1 to 7, characterized in that, In any polarization direction, each superframe includes a frame synchronization symbol located at the end of any subframe within the superframe. The method according to claim 8, characterized in that, The frame synchronization symbol is located at the end of the last subframe in the superframe. The method according to claim 8 or 9, characterized in that, In any polarization direction, each superframe includes a first type of subframe; In each superframe, symbols other than training symbols, pilot symbols, payload symbols, and frame synchronization symbols are located after and adjacent to the training symbols in the first type of subframe. The method according to claim 8 or 9, characterized in that, In any polarization direction, in each superframe, all symbols except the training symbol, pilot symbol, payload symbol, and frame synchronization symbol are located before and adjacent to the frame synchronization symbol. The method according to any one of claims 1 to 11, characterized in that, The W dual-polarization symbol streams are carried on W subcarriers respectively. The method according to any one of claims 1 to 12, characterized in that, The W dual-polarization symbol streams are generated by a series of consecutive bits. The method according to any one of claims 1 to 13, characterized in that, In any polarization direction, both the first and second superframes include 87,552 symbols, of which 86,016 are payload symbols. Each subframe of the first and second superframes includes 7,296 symbols; or... In any polarization direction, both the first superframe and the second superframe include 175,104 symbols, of which 175,104 symbols include 172,023 payload symbols. Each subframe of the first superframe and the second superframe includes 7,296 symbols. A method for data transmission, characterized in that, The method includes: Receive W dual-polarization symbol streams after transmission, wherein the first dual-polarization symbol stream includes a first superframe, and the second dual-polarization symbol stream includes a second superframe; in any polarization direction, every consecutive N subframes of the first superframe and the second superframe... PG Each symbol includes a pilot symbol, and the i-th pilot symbol of each subframe of the first superframe is the i-th group of consecutive N symbols. PG The j-th symbol in the N symbols, and the i-th pilot symbol in each subframe of the second superframe is the i-th group of consecutive N symbols. PG The (j+m)th symbol in the set of symbols, W is greater than 1, i is greater than or equal to 1, j and m are both positive integers, and j+m is less than or equal to N. PG . The method according to claim 15, characterized in that, m and (N) PG / W)×a is related, 1≤a<W, where a is an integer. The method according to claim 15, characterized in that, m is greater than or equal to 16. The method according to claim 17, characterized in that, W is 2, N PG The value is 64, and m is 32. The method according to any one of claims 15 to 17, characterized in that, When W is 4, the third dual-polarization symbol stream in the W dual-polarization symbol streams includes a third superframe, and the fourth dual-polarization symbol stream includes a fourth superframe; in any polarization direction, every consecutive N in each subframe of the third superframe and the fourth superframe PG Each symbol includes a pilot symbol, and the i-th pilot symbol of each subframe of the third superframe is the i-th group of consecutive N symbols. PG The (j+2m)th symbol in the set of symbols, and the i-th pilot symbol of each subframe of the fourth superframe is the i-th group of consecutive N symbols. PG The (j+3m)th symbol among the symbols, where both (j+2m) and (j+3m) are less than or equal to N. PG . The method according to claim 19, characterized in that, N PG The value is 64, and m is 16. The method according to any one of claims 15 to 20, characterized in that, j is 1. The method according to any one of claims 15 to 21, characterized in that, In any polarization direction, each superframe includes a frame synchronization symbol located at the end of any subframe within the superframe. The method according to claim 22, characterized in that, The frame synchronization symbol is located at the end of the last subframe in the superframe. A data transmission device, characterized in that, The device includes: A transmitting unit is configured to transmit W dual-polarization symbol streams, wherein the first dual-polarization symbol stream comprises a first superframe, and the second dual-polarization symbol stream comprises a second superframe; in any polarization direction, every consecutive N subframes of the first superframe and the second superframe... PG Each symbol includes a pilot symbol, and the i-th pilot symbol of each subframe of the first superframe is the i-th group of consecutive N symbols. PG The j-th symbol in the N symbols, and the i-th pilot symbol in each subframe of the second superframe is the i-th group of consecutive N symbols. PG The (j+m)th symbol in the set of symbols, W is greater than 1, i is greater than or equal to 1, j and m are both positive integers, and j+m is less than or equal to N. PG . A data transmission device, characterized in that, The device includes: The receiving unit is configured to receive W dual-polarization symbol streams obtained through transmission, wherein the first dual-polarization symbol stream comprises a first superframe, and the second dual-polarization symbol stream comprises a second superframe; in any polarization direction, every consecutive N subframes of the first superframe and the second superframe... PG Each symbol includes a pilot symbol, and the i-th pilot symbol of each subframe of the first superframe is the i-th group of consecutive N symbols. PG The j-th symbol in the N symbols, and the i-th pilot symbol in each subframe of the second superframe is the i-th group of consecutive N symbols. PG The (j+m)th symbol in the set of symbols, W is greater than 1, i is greater than or equal to 1, j and m are both positive integers, and j+m is less than or equal to N. PG . A chip characterized in that, The chip is used to perform the method as described in any one of claims 1 to 23. 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 23. A communication device, characterized in that, The communication device includes a host-side device and an optical module as described in claim 27. The optical module is used to convert an electrical signal from the host-side device into an optical signal and transmit the optical signal, or the optical module is used to convert a received optical signal into an electrical signal and transmit the electrical signal to the host-side device. A communication system, characterized in that, The communication system includes a plurality of communication devices as described in claim 28, wherein the plurality of communication devices are used to send optical signals to each other.

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