Signal receiving method, signal transmitting method, terminal, system, and storage medium

Abstract

This application provides a signal receiving method, a transmitting method, a terminal, a system, and a storage medium, relating to, but not limited to, the field of optical communication technology. The receiving terminal removes a unique header from the time-domain signal data according to a first preset length. The time-domain signal data is obtained by transmitting the original signal data from the transmitting terminal through a transmission channel and is a linear convolution of the original signal data and the channel impulse response of the transmission channel. The original signal data includes a data group composed of a unique header of the first preset length and symbol data of the second preset length. Multiple intermediate time-domain data blocks are constructed from the time-domain signal data after removing the unique header, based on the length of the data group, so that each intermediate time-domain data block corresponds to a circular convolution of a data group and the channel impulse response. Frequency domain equalization is performed on the intermediate time-domain data blocks to obtain first equalized time-domain signal data. The embodiments of this application can improve the communication quality of the optical communication system while maintaining transmission capacity.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of optical communication technology, and particularly to a signal receiving method, a transmitting method, a terminal, a system, and a storage medium. Background Technology

[0002] With the continuous emergence of new internet services such as social networks, cloud computing, and virtual reality, the amount of data generated and the demand for communication capacity are growing exponentially. Due to the limitations of fiber nonlinearity, existing standard single-mode fiber cannot meet the demands for transmission capacity. According to Shannon's channel capacity theory, under the same bandwidth constraint, increasing channel capacity requires increasing the signal-to-noise ratio, leading to higher signal power and greater fiber nonlinearity, thus increasing the cost of compensating for nonlinearity. Against this backdrop, optical fiber spatial division multiplexing (SDM) technology has been proposed for optical communication systems. It utilizes a series of fiber channels to transmit independent data, thereby increasing the channel capacity of a single fiber. Among related technologies, SDM technology uses two modes for data transmission: mode multiplexing and fiber core multiplexing. One of the important factors affecting the communication quality of optical communication systems in both modes is the computational complexity of signal equalization. However, due to the inherent structure of the optical fiber, the computational complexity of channel equalization is very high. Therefore, how to further improve channel quality while ensuring channel capacity in optical communication systems using SDM technology is a pressing problem to be solved. Summary of the Invention

[0003] This application provides a signal receiving method, a transmitting method, a terminal, a system, and a storage medium, aiming to further improve the communication quality of optical communication systems while taking into account transmission capacity.

[0004] In a first aspect, embodiments of this application provide a signal receiving method applied to a receiving terminal of an optical communication system. The optical communication system includes a transmitting terminal and the receiving terminal, the transmitting terminal being communicatively connected to the receiving terminal. The signal receiving method includes:

[0005] Receive time-domain signal data; wherein the time-domain signal data is obtained by transmitting the original signal data sent by the transmitting terminal through the transmission channel, and the time-domain signal data is equal to the linear convolution of the original signal data and the channel impulse response of the transmission channel; the original signal data includes multiple data groups with a first period length, each data group consisting of a unique word of a first preset length and symbol data of a second preset length;

[0006] Based on the first preset length, remove the unique word header of the time-domain signal data;

[0007] Based on the first period length, the time-domain signal data after removing the unique word header is divided to construct multiple time-domain intermediate data blocks, so that each time-domain intermediate data block corresponds to a data group and the circular convolution of the channel impulse response.

[0008] The intermediate time-domain data block is subjected to frequency-domain equalization to obtain the first equalized time-domain signal data corresponding to the original signal data.

[0009] Secondly, embodiments of this application provide a signal transmission method applied to a transmitting terminal of an optical communication system. The optical communication system includes the transmitting terminal and a receiving terminal, the transmitting terminal and the receiving terminal being communicatively connected. The signal transmission method includes:

[0010] Obtain a data sequence to be sent, the data sequence to be sent including multiple symbol data;

[0011] For every second preset length of symbol data, a unique word of a first preset length is inserted into the data sequence to be transmitted to generate original signal data including multiple data groups with a first period length. The first preset symbol length is greater than or equal to the length of the channel impulse response, and the first period length is equal to the sum of the first preset length and the second preset length.

[0012] The original signal data is sent to the receiving terminal so that the receiving terminal performs the signal receiving method as described in the first aspect.

[0013] Thirdly, embodiments of this application provide a transmitting terminal for an optical communication system, comprising:

[0014] A laser is used to emit a beam of light;

[0015] A first controller is configured to generate original signal data by executing the signal transmission method as described in the second aspect;

[0016] A modulator is used to modulate the beam emitted by the laser according to the original signal data to generate a modulated optical signal that is sent to the receiving terminal.

[0017] Fourthly, embodiments of this application provide a receiving terminal for an optical communication system, comprising:

[0018] An optical receiver is used to receive modulated optical signals from a transmitting terminal and convert the modulated optical signals into time-domain signal data.

[0019] The second controller is communicatively connected to the optical receiver and is used to receive the time-domain signal data and process the time-domain signal data using the signal receiving method as described in the first aspect.

[0020] Fifthly, embodiments of this application provide an optical communication system, including:

[0021] The transmitting terminal as described in the third aspect;

[0022] Transmission channel, used to transmit modulated optical signals;

[0023] The receiving terminal as described in the fourth aspect.

[0024] In a sixth aspect, embodiments of this application provide a storage medium including computer-executable instructions stored thereon, the computer-executable instructions being used to perform the signal receiving method as described in any of the first aspects and / or the signal transmitting method as described in the second aspect.

[0025] The above embodiments of this application have at least the following beneficial effects: By obtaining time-domain signal data with a period of two preset lengths and a unique word of a first preset length inserted in the middle of the data sequence to be transmitted at the transmitting terminal, the receiving terminal can construct a time-domain intermediate data block after removing the unique word header from the time-domain signal data. This transforms the linear convolution between the original signal data and the channel impulse response into a circular convolution of multiple time-domain intermediate data blocks, thereby achieving frequency-domain processing of the entire channel equalization process. Compared to related technologies, the embodiments of this application are mode-independent, only requiring consideration of the unique word length and the division of the time-domain intermediate data block, resulting in lower complexity. Therefore, the embodiments of this application further improve the communication quality of the optical communication system while maintaining transmission capacity.

[0026] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a module of an optical communication system provided in an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of a time-domain signal data structure received by a receiving terminal in an optical communication system according to an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of the structure of a transmitting terminal in an optical communication system provided in an embodiment of this application;

[0030] Figure 4 This is a schematic flowchart illustrating a signal receiving method provided in one embodiment of this application.

[0031] Figure 5This is a schematic diagram of a time-domain signal data structure in a signal receiving method provided in an embodiment of this application;

[0032] Figure 6 This is a schematic diagram illustrating the processing of time-domain signal data in a signal receiving method provided in an embodiment of this application;

[0033] Figure 7 A schematic diagram of the channel equalization process in an application scenario of the signal receiving method provided in an embodiment of this application;

[0034] Figure 8 This is a schematic diagram of the channel equalization process in another application scenario of the signal receiving method provided in an embodiment of this application.

[0035] Figure 9 This is a schematic diagram of the channel equalization process in another application scenario of the signal receiving method provided in an embodiment of this application.

[0036] Figure 10 This is a schematic flowchart of a signal transmission method provided in an embodiment of this application.

[0037] Figure label:

[0038] Transmitting terminal 100, laser 110, first controller 120,

[0039] Receiving terminal 200, optical receiver 210, second controller 220,

[0040] Transmission channel 300, multiplexing unit 310, optical fiber 320, demultiplexing unit 330. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0042] The following is an explanation of the terms used in this application:

[0043] A unique word (UW) is a special code group that is not easily counterfeited by random bits, thus preventing false detection.

[0044] Channel equalization: In communication systems, the channel is the most important factor affecting signal transmission quality. The purpose of channel equalization is to eliminate the influence of the channel.

[0045] FFT, or Fast Fourier Transform, is a fast algorithm for the Discrete Fourier Transform, which can transform a signal from the time domain to the frequency domain.

[0046] IFFT, or Inverse Fast Fourier Transform, is a fast algorithm for the discrete inverse Fourier transform.

[0047] S / P: Serial-to-Parallel Conversion, which converts high-speed serial signals into low-speed parallel signals.

[0048] P / S: Parallel-to-serial conversion, the process of transforming a set of parallel signal elements into a corresponding continuous sequence of signal elements representing the same information.

[0049] A PLL, or phase-locked loop, is a frequency and phase synchronization technique that uses feedback control principles. Its function is to keep the circuit's output clock synchronized with its external reference clock. When the frequency or phase of the reference clock changes, the PLL detects this change and adjusts the output frequency through its internal feedback system until the two are resynchronized. This synchronization is also known as "phase locking".

[0050] FIR (Finite Impulse Response) filter: A finite-length unit impulse response filter, also known as a non-recursive filter, is the most basic component in digital signal processing systems. It can guarantee arbitrary amplitude-frequency characteristics while having strictly linear phase-frequency characteristics. At the same time, its unit sample response is finite-length, so the filter is a stable system.

[0051] Dispersion length is a length scale introduced in nonlinear optics to measure the effect of dispersion on light pulses.

[0052] Channel Impulse Response (CIR) is the signal energy value that a signal takes at different times to reach the receiver (different propagation paths result in different propagation times). Simply put, it's the response at the receiver when a pulse signal is sent from the transmitter. Due to multipath delay spread and Doppler shift, different receivers will have different channel impulse responses, and even different locations will have different CIRs due to multipath propagation.

[0053] The LMS algorithm, or Least Mean Square algorithm, is an improved version of the steepest descent algorithm. This algorithm does not require known statistical characteristics of the input and desired signals. The weight coefficients at the "current moment" are obtained by adding a proportional term of the negative mean square error gradient to the weight coefficients at the "previous moment".

[0054] With the continuous emergence of new internet services such as social networks, cloud computing, and virtual reality, the amount of data generated and the demand for communication capacity are growing exponentially. Due to the limitations of fiber nonlinearity, existing standard single-mode fiber cannot meet the demands for transmission capacity. According to Shannon's channel capacity theory, under the same bandwidth constraint, increasing channel capacity requires increasing the signal-to-noise ratio, leading to higher signal power and greater fiber nonlinearity, thus increasing the cost of compensating for nonlinearity. Against this backdrop, optical fiber spatial division multiplexing (SDM) technology has been proposed for optical communication systems. It utilizes a series of fiber channels to transmit independent data, thereby increasing the channel capacity of a single fiber. Among related technologies, SDM technology uses two modes for data transmission: mode multiplexing and fiber core multiplexing. One of the important factors affecting the communication quality of optical communication systems in both modes is the computational complexity of signal equalization. However, due to the inherent structure of the optical fiber, the computational complexity of channel equalization is very high. Therefore, how to further improve channel quality while ensuring channel capacity in optical communication systems using SDM technology is a pressing problem to be solved.

[0055] Based on this, this application proposes a signal receiving method, a transmitting method, a terminal, a system, and a storage medium, aiming to further improve the communication quality of the optical communication system while ensuring channel capacity.

[0056] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0057] Figure 1 This is a schematic diagram of a system architecture for performing a signal transmission method and a signal reception method according to an embodiment of this application. Figure 1 In the example, the system architecture includes a transmitting terminal 100, a transmission channel 300, and a receiving terminal 200.

[0058] The transmitting terminal 100 includes a laser 110, a first controller 120, and a modulator 130.

[0059] Laser 110 is used to emit a light beam. That is to say, laser 110 acts as a light source to emit a light beam.

[0060] The first controller 120 is used to generate the original signal data. For example, the first controller 120 can perform orthogonal encoding (data modulation) on the data sequence to be transmitted, and then add UW to obtain an electrical signal containing the original signal data. The original signal data is obtained through the following steps:

[0061] Obtain the data sequence to be sent, which includes multiple symbol data;

[0062] For every second preset length of symbol data, a unique word of the first preset length is inserted into the data sequence to be transmitted to generate original signal data including multiple data groups with a first period length. The first preset symbol length is greater than or equal to the length of the channel impulse response, and the first period length is equal to the sum of the first preset length and the second preset length.

[0063] The original signal data is sent to the receiving terminal 200, so that the receiving terminal 200 removes the unique word header of the time-domain signal data corresponding to the original signal data, constructs multiple time-domain intermediate data blocks, and performs channel equalization processing on the time-domain intermediate data blocks to obtain the first equalized time-domain signal data corresponding to the original signal data.

[0064] It should be noted that in some embodiments, the first controller 120 includes a redundant codeword addition module, thereby ensuring that the data sequence to be transmitted can be divided into multiple symbol data of the same second preset length, so that the original signal data can be composed of multiple data groups with a first period length.

[0065] Modulator 130 is used to modulate the beam emitted by laser 110 according to the original signal data to generate a modulated optical signal that is sent to receiving terminal 200. Modulator 130 acts as an electro-optic conversion module, converting an electrical signal containing the original signal data into a modulated optical signal for transmission. In one possible implementation, modulator 130 can be used to receive the beam emitted by laser 110, generate an optical carrier based on the beam, and modulate the electrical signal containing the original signal data onto the optical carrier to obtain a modulated optical signal. It should be noted that modulator 130 can be configured as a coherent optical modulator 130.

[0066] For example, refer to Figure 3 As shown, after the first controller 120 acquires the data sequence to be transmitted, it sequentially performs data modulation, UW addition, and matched filtering to obtain multiple original signal data, including multiple data groups with a first period length. The original signal data is then used by the laser 110 and the modulator 130 to generate a modulated optical signal that can be transmitted in the transmission channel 300.

[0067] Understandably, referring to Figure 3 As shown, the transmission channel 300 includes:

[0068] Multiplexing unit 310 is used to combine modulated optical signals of different wavelengths from transmitting terminal 100. The main function of multiplexing unit 310 is to multiplex modulated optical signals of multiple wavelengths into (fan-in) a single optical fiber using wavelength division multiplexing.

[0069] Optical fiber 320 is connected to multiplexing unit 310 and is used to transmit the combined modulated optical signal. Optical fiber 320 is a multimode fiber or a few-mode fiber.

[0070] The demultiplexing unit 330, connected to the optical fiber 320, receives the merged modulated optical signals transmitted through the optical fiber 320, separates the merged modulated optical signals, and sends them to the receiving terminal 200. The main function of the demultiplexing unit 330 is to separate the modulated optical signals fanned out from the optical fiber 320 into their respective frequencies for output to the optical receiver 210.

[0071] It should be noted that the multiplexing unit 310 can be configured as a mode coupler or a fiber core coupler. The modulated optical signal output by the transmitting terminal 100 is coupled in the optical fiber 320 after passing through the multiplexing unit 310. It should also be noted that the demultiplexing unit 330 can be configured as a mode decoupler or a fiber core decoupler. The demultiplexing unit 330 separates the modulated optical signals of different modes (i.e., different wavelengths) transmitted in the optical fiber 320, and the receiving terminal 200 completes the reception and parsing of the separated modulated optical signals.

[0072] For example, consider D modulated optical signals of different wavelengths entering transmission channel 300. (Refer to...) Figure 3 As shown, the D-channel modulated optical signals of different wavelengths enter the optical fiber 320 through the multiplexing unit 310 and are coupled in the optical fiber 320. At this time, the demultiplexing unit 330 separates the D-channel modulated optical signals of different wavelengths so that the receiving terminal 200 can perform coherent reception, and synchronize and analyze the received D-channel modulated optical signals.

[0073] The receiving terminal 200 of the optical communication system includes:

[0074] Optical receiver 210 is used to receive modulated optical signals from transmitting terminal 100 and convert the modulated optical signals into time-domain signal data;

[0075] The second controller 220 is communicatively connected to the optical receiver 210 and is used to receive time-domain signal data and process the time-domain signal data as follows:

[0076] Receive time-domain signal data; wherein, the time-domain signal data is obtained by transmitting the original signal data sent by the transmitting terminal 100 through the transmission channel 300, and the time-domain signal data is equal to the linear convolution of the original signal data and the channel impulse response of the transmission channel 300; the original signal data includes multiple data groups with a first period length, each data group consisting of a unique word of a first preset length and symbol data of a second preset length;

[0077] Based on the first preset length, remove the unique word header of the time-domain signal data;

[0078] Based on the length of the first period, the time-domain signal data after removing the unique word header is divided into multiple time-domain intermediate data blocks, so that each time-domain intermediate data block corresponds to a circular convolution of a data group and the channel impulse response.

[0079] Frequency domain equalization is performed on the intermediate time-domain data block to obtain the first equalized time-domain signal data corresponding to the original signal data.

[0080] It should be noted that, referring to Figure 6 As shown, in some embodiments, the second controller 220 includes a data synchronization module, a unique word header removal module, a matched filtering module, a serial-to-parallel conversion module, an equalization module, a unique word removal module, a parallel-to-serial conversion module, and a symbol decoding module. The data synchronization module synchronizes the received multi-channel modulated optical signals to obtain multiple time-domain signal data. The unique word header removal module removes unique word headers from the time-domain signal data according to a first preset length and divides the time-domain signal data after unique word header removal according to a first period length to construct multiple intermediate time-domain data blocks. The equalization module performs frequency domain equalization on the intermediate time-domain data blocks to obtain first equalized time-domain signal data corresponding to the original signal data, and outputs second equalized time-domain signal data after phase noise compensation based on the first equalized time-domain signal data. The unique word removal module removes unique words from the output second equalized time-domain signal data of the equalization module to obtain data to be decoded. The parallel-to-serial conversion module performs parallel-to-serial conversion on the data to be decoded, and the symbol decoding module decodes the parallel-to-serial converted data to obtain the target signal data.

[0081] It is understandable that the receiving terminal 200 is used for:

[0082] Receive time-domain signal data; wherein, the time-domain signal data is obtained by transmitting the original signal data sent by the transmitting terminal 100 through the transmission channel 300;

[0083] Based on the first preset length, remove the unique word header of the time-domain signal data;

[0084] Based on the length of the first period, the time-domain signal data after removing the unique word header is divided into multiple time-domain intermediate data blocks, so that each time-domain intermediate data block corresponds to a circular convolution of a data group and the channel impulse response.

[0085] Frequency domain equalization is performed on the intermediate time-domain data block to obtain the first equalized time-domain signal data corresponding to the original signal data.

[0086] For example, suppose the data sequence to be transmitted is x = [x0, x1, x2, x3, x4, x5], consisting of 6 symbols. The first preset length is 1, and the second preset length is 3. Then the first cycle length is 4. In this case, the data sequence to be transmitted after inserting the unique word is x. UW =[uw1,x0,x1,x2,uw1,x3,x4,x5], where, x 1 =[uw1,x0,x1,x2]、x2 = [uw1, x3, x4, x5] are data groups. When the channel impulse response h = [h0, h1], the time-domain signal data y obtained after the original signal data passes through the channel response is:

[0087]

[0088] Correspondingly, the UW header of the time-domain signal data y is the data located at the first preset length, i.e., h0uw1. At this time, the time-domain signal data after removing the UW header...

[0089] At this time, refer to Figure 2 The data structure of the time-domain signal data shown can be considered as the concatenation of the results of circular convolutions of each data group with the channel impulse response, i.e., it is equal to the concatenation of C1 and C2, where C1 is x. 1 The result of the circular convolution of [uw1,x0,x1,x2] and h = [h0,h1], where C2 is x 2 The result of the circular convolution of [uw1,x3,x4,x5] and h = [h0,h1]. At this point, refer to... Figure 2 As shown, by dividing the data proportionally according to the length of the first cycle, two intermediate time-domain data blocks can be obtained. One intermediate time-domain data block is FFT1 = [h1uw1 + h0x0, h1x0 + h0x1, h1x1 + h0x2, h1x2 + h0uw1], and the other intermediate time-domain data block is FFT2 = [h1uw1 + h0x3, h1x3 + h0x4, h1x4 + h0x5, h1x5 + h0uw1]. The circular convolution in the time domain corresponds to the product of the intermediate time-domain data block and the channel response in the frequency domain. That is, the intermediate time-domain data block Y, the channel response H, and the data group X in the frequency domain have the following relationship: Y = HX. Therefore, when the filter response W = 1 / H, frequency domain equalization can be achieved using simple multiplication in the frequency domain, and the time-domain signal data of each mode or fiber core can be processed independently, thereby reducing the complexity of channel equalization.

[0090] Therefore, the optical communication system of this application inserts a unique word of a first preset length into the middle of the data sequence to be transmitted by the transmitting terminal 100 at a period of a second preset length, thereby obtaining the time-domain signal data received by the receiving terminal 200. After removing the unique word header from the time-domain signal data, a time-domain intermediate data block is constructed. This transforms the linear convolution between the original signal data and the channel impulse response into a circular convolution of multiple time-domain intermediate data blocks, thus enabling frequency-domain processing of the entire channel equalization process. Compared with related technologies, the embodiments of this application are mode-independent, only requiring consideration of the length of the unique word and the division of the time-domain intermediate data block, resulting in lower complexity. Therefore, the embodiments of this application further improve the communication quality of the optical communication system while maintaining transmission capacity.

[0091] The system architecture and application scenarios described in this application are intended to more clearly illustrate the technical solutions of this application and do not constitute a limitation on the technical solutions provided in this application. Those skilled in the art will understand that as system architectures evolve and new application scenarios emerge, the technical solutions provided in this application are also applicable to similar technical problems.

[0092] It will be understood by those skilled in the art that Figure 1 The system architecture shown does not constitute a limitation on the embodiments of this application. It may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0093] exist Figure 1 In the system architecture shown, each device can call its stored signal sending program and signal receiving program to execute the signal sending method or the signal receiving method.

[0094] Based on the above system architecture, various embodiments of the signal transmission method and signal reception method of this application are proposed.

[0095] According to the signal receiving method provided in this application, a receiving terminal 200 of an optical communication system is applied. The optical communication system includes a transmitting terminal 100 and a receiving terminal 200, which are communicatively connected. (Refer to...) Figure 4 As shown, the signal receiving method includes:

[0096] Step S100: Receive time-domain signal data; wherein, the time-domain signal data is obtained by transmitting the original signal data sent by the transmitting terminal 100 through the transmission channel 300, and the time-domain signal data is equal to the linear convolution of the original signal data and the channel impulse response of the transmission channel 300; the original signal data includes multiple data groups with a first period length, each data group consisting of a unique word of a first preset length and symbol data of a second preset length;

[0097] Step S110: Remove the unique word header of the time domain signal data according to the first preset length;

[0098] Step S120: Based on the length of the first period, divide the time-domain signal data after removing the unique word header and construct multiple time-domain intermediate data blocks so that each time-domain intermediate data block corresponds to a circular convolution of a data group and the channel impulse response.

[0099] Step S130: Perform frequency domain equalization processing on the intermediate time domain data block to obtain the first equalized time domain signal data corresponding to the original signal data.

[0100] Therefore, by obtaining time-domain signal data with a period of two preset lengths and inserting a unique word of a first preset length into the data sequence to be transmitted in the transmitting terminal 100, the receiving terminal 200 can construct intermediate time-domain data blocks after removing the unique word header from the time-domain signal data. This transforms the linear convolution between the original signal data and the channel impulse response into a circular convolution of multiple intermediate time-domain data blocks, thereby achieving full-process frequency-domain processing for channel equalization. Compared to related technologies, the embodiments of this application are mode-independent, only requiring consideration of the unique word length and the division of intermediate time-domain data blocks, resulting in lower complexity. Therefore, the embodiments of this application further improve the communication quality of the optical communication system while maintaining transmission capacity.

[0101] It should be noted that the unique header indicates the first preset length of symbol data located before the time-domain signal data.

[0102] It should be noted that the first preset length is greater than or equal to the length of the channel impulse response, so that when frequency domain equalization is performed based on the intermediate data block in the time domain, crosstalk caused by the channel can be compensated.

[0103] It should be noted that the frequency domain filters used in the frequency domain equalization process are all based on the LMS adaptive filtering algorithm. Each wavelength corresponds to an independent LMS algorithm, so that the frequency domain intermediate data corresponding to the time domain intermediate data block is compensated for by the frequency domain filter and the first equalized time domain signal data can be obtained by simply passing through one IFFT.

[0104] It should be noted that the number of intermediate data blocks in the time domain is equal to the number of data groups.

[0105] It should be noted that, taking an optical communication system with D modes as an example, based on a first preset length of N... UW The complexity of calculating the complex multiplication required for each pattern and each symbol to balance unique characters is as follows:

[0106]

[0107] Where, NFFT This indicates the length of the intermediate data block in the time domain, which is also the length of the first cycle.

[0108] It should be noted that the complexity of time-domain equalization processing is higher than that of frequency-domain equalization processing. In related technologies, frequency-domain equalization processing often employs the overlap-preservation method, but the complexity of the overlap-preservation method is proportional to the product of the logarithm of the FIR filter length (log₂L) and the number of modes D (Dlog₂L). Therefore, compared with related technologies, the channel equalization in this application has lower complexity.

[0109] Understandably, step S110, removing the unique word header of the time-domain signal data according to the first preset length, includes:

[0110] Get the length of the first sequence of unique characters;

[0111] Remove the data located at the first sequence length position of the time-domain signal data;

[0112] Based on the length of the first cycle, the time-domain signal data after removing the unique word header is divided into multiple time-domain intermediate data blocks, including:

[0113] The removed time-domain signal data is divided according to the length of the first cycle to obtain multiple intermediate time-domain data blocks with the same length as the data group.

[0114] For example, assuming the length of the data group is 6, then the length of the intermediate data block in the time domain is 6. If the number of data groups is 2, then the number of intermediate data blocks in the time domain is also 2.

[0115] For example, with a first preset length of 3 and a second preset length of 2, the original signal data is x'. UW = [uw1,uw2,x0,x1,x2,uw1,uw2,x3,x4,x5], then the time-domain signal data y” is as follows:

[0116]

[0117] At this point, the structure of the time-domain signal data y″ is shown in [reference]. Figure 5 As shown, at this point, the unique word header of the time-domain signal data y″ is (h0uw1, h1uw1+h0uw2). At this time, the same number and length of intermediate time-domain data blocks as the data set can be constructed, namely:

[0118] FFT'1=[h2uw1+h1uw2+h0x0,h2uw2+h1x0+h0x1,h2x0+h1x1+h0x2,h2x1+h1x2+h0uw1,h2x2+h1uw1+h0uw2];

[0119] FFT'2=[h2uw1+h1uw2+h0x3,h2uw2+h1x3+h0x4,h2x3+h1x4+h0x5,h2x4+h1x5+h0uw1,h2x5+h1uw1+h0uw2].

[0120] Understandably, referring to Figure 6 As shown, frequency domain equalization is performed on the intermediate time-domain data block to obtain the first equalized time-domain signal data corresponding to the original signal data, including:

[0121] Perform a Fourier transform on each intermediate data block in the time domain to obtain intermediate data in the frequency domain;

[0122] Channel equalization processing is performed on the intermediate frequency domain data using a frequency domain filter with first model parameters to obtain the first frequency domain equalized signal data corresponding to the intermediate frequency domain data.

[0123] Perform an inverse Fourier transform on the first frequency domain equalized signal data to obtain the first equalized time domain signal data corresponding to the original signal data.

[0124] It should be noted that the first model parameter is used to represent the response of the frequency domain filter, i.e., the tap coefficients.

[0125] For example, refer to Figure 6 As shown, when the frequency domain filter satisfies the first model parameter W = 1 / H, then refer to Figure 6 In step ①, the intermediate time-domain data block y is transformed using FFT to obtain intermediate frequency-domain data Y. Referring to step ②, Y is used as the input value of the frequency-domain filter to obtain the first frequency-domain equalized signal data X. This ensures that each intermediate time-domain data block outputs the first equalized frequency-domain signal data after passing through the frequency-domain filter. Then, referring to step ③, X is transformed using IFFT to obtain the first equalized time-domain signal data.

[0126] Understandably, referring to Figure 6 As shown, after performing an inverse Fourier transform on the first frequency domain equalization signal data to obtain the first equalization time domain signal data corresponding to the original signal data, the signal receiving method further includes:

[0127] Phase noise compensation is performed on the first equalized time-domain signal data to obtain the second equalized time-domain signal data;

[0128] The second equalized time-domain signal data is used to make a decision to obtain the target time-domain signal data corresponding to the original signal data.

[0129] It should be noted that phase noise compensation can be performed using pilot-based or phase-locked loop (PLL) methods.

[0130] It should be noted that making a decision on the second equalized time-domain signal data can make the target time-domain signal data more reliable, so that after updating the first model parameters of the frequency-domain filter, the first frequency-domain equalized signal data output by the frequency-domain filter is more accurate.

[0131] Understandably, referring to Figure 6 As shown, after making a decision on the second equalized time-domain signal data to obtain the target time-domain signal data corresponding to the original signal data, the signal receiving method further includes:

[0132] The frequency domain error is determined based on the first frequency domain equalization signal data and the target time domain signal data;

[0133] Based on the frequency domain error, determine the convergence compensation value for channel equalization processing;

[0134] The first model parameters of the frequency domain filter are updated based on the convergence compensation value, so that the frequency domain filter with updated first model parameters can perform channel equalization processing on the next frequency domain intermediate data to obtain the corresponding first frequency domain equalized signal data.

[0135] It should be noted that the frequency domain error can be calculated by converting the target time-domain signal data into frequency-domain data based on the strength of the phase noise, or by calculating the error between the first frequency-domain equalized signal data (without phase noise compensation in the time domain) and the target time-domain signal data, followed by conversion to the frequency domain. In some embodiments, the frequency domain error can be directly calculated by converting the target time-domain signal data into frequency-domain data; in other embodiments, the frequency domain error can be directly calculated by converting the first frequency-domain equalized signal data (after time-domain conversion) and the target time-domain signal data, followed by conversion to the frequency domain.

[0136] It should be noted that an FIR filter is used in this application. Therefore, the update of the first model parameters is the sum of the current first model parameters and the convergence compensation value.

[0137] Understandably, referring to Figure 7 As shown, based on the first frequency domain equalization signal data and the target time domain signal data, the frequency domain error is determined, including:

[0138] Calculate the reference frequency domain signal data after Fourier transforming the target time domain signal data;

[0139] The frequency domain error is obtained by calculating the difference between the reference frequency domain signal data and the first frequency domain equalized signal data.

[0140] It should be noted that when the phase noise is weak, the target time-domain signal data after phase noise compensation has a relatively small impact on the convergence of the equalization algorithm. Therefore, the target time-domain signal data obtained after the decision can be converted into time-domain data for frequency domain error calculation.

[0141] Understandably, referring to Figure 8 As shown, based on the first frequency domain equalization signal data and the target time domain signal data, the frequency domain error is determined, including:

[0142] Calculate the time-domain signal error between the target time-domain signal data and the first equalized time-domain signal data;

[0143] The frequency domain error is obtained by performing a Fourier transform on the time-domain signal error.

[0144] It should be noted that when the phase noise is strong, the relevant error signal needs to be corrected for the phase noise in the time domain. Therefore, it is necessary to transfer the calculation of the error signal to the time domain to ensure that the accuracy of the time domain signal error meets the requirements.

[0145] Understandably, referring to Figure 9 As shown, based on the first frequency domain equalization signal data and the target time domain signal data, the frequency domain error is determined, including:

[0146] The phase noise compensation value is obtained by acquiring the first equalized time-domain signal data and performing phase noise compensation.

[0147] The phase noise compensation value is applied to the target time domain signal data to obtain the reference time domain signal data;

[0148] Calculate the time-domain signal error between the reference time-domain signal data and the first equalized time-domain signal data;

[0149] The frequency domain error is obtained by performing a Fourier transform on the time-domain signal error.

[0150] It should be noted that the phase noise compensation value is added to the target time domain signal data so that the reference time domain signal data and the first equalized time domain signal data have the same phase noise, thereby ensuring the transparency of the phase noise to the equalization algorithm of the frequency domain filter.

[0151] It should be noted that in some embodiments, the phase noise strength of the channel in the current processing cycle is obtained, and a strong phase noise scenario is determined when the phase noise is greater than a certain threshold, and a weak phase noise scenario is determined otherwise. Under strong phase noise, the time domain error is calculated first and then the frequency domain error is calculated; under weak phase noise, the frequency domain error is calculated directly.

[0152] For example, taking the compensation of phase noise for the target time-domain signal data under strong phase noise as an example, under weak phase noise, refer to Figure 6As shown in (a), ① the intermediate time-domain data block y is output as intermediate frequency-domain data Y via FFT; ② the intermediate frequency-domain data Y is filtered by a frequency-domain filter to obtain the first frequency-domain equalized signal data X; ③ the first frequency-domain equalized signal data X is output as first equalized time-domain signal data x via IFFT. Then, the first equalized time-domain signal data x undergoes phase noise compensation via PLL to obtain the second equalized time-domain signal data. After the second time-domain equalized signal data is used for decision-making, the target time-domain signal data is output. Target time domain signal data FFT outputs reference frequency domain signal data See point ④ here: Reference frequency domain signal data Subtracting the first frequency domain equalization signal data X from the first frequency domain equalization signal data X yields the frequency domain error. Referring to step ⑤, multiplying the frequency domain error by the intermediate frequency domain data Y calculates the first compensation amount, thereby updating the first model parameter W of the frequency domain filter. k+1 =W k +E k Y k Among them, W k E represents the initial model parameters before the update. k This represents frequency domain error. In cases of strong phase noise, such as... Figure 6 As shown in (b), ① the intermediate time-domain data block y is output as intermediate frequency-domain data Y via FFT; ② the intermediate frequency-domain data Y is filtered by a frequency-domain filter to obtain the first frequency-domain equalized signal data X; ③ the first frequency-domain equalized signal data X is output as first equalized time-domain signal data x via IFFT. The first equalized time-domain signal data x is subjected to phase noise compensation by a PLL to obtain the second equalized time-domain signal data. After decision-making, the second time-domain equalized signal data is output as the target time-domain signal data. The target time-domain signal data is then subjected to phase noise addition to obtain the reference time-domain signal data. See point ④ here: Reference time-domain signal data Subtracting the first equalized time-domain signal data x from the time-domain data yields the time-domain error. The time-domain error is then processed by FFT to output the frequency-domain error E. k And refer to ⑤ to calculate the first compensation amount by multiplying the frequency domain error by the intermediate frequency domain data Y, thereby updating the first model parameter W of the frequency domain filter. k+1 =W k +E k Y k .

[0153] Understandably, based on the frequency domain error, the convergence compensation value for channel equalization processing is determined, including:

[0154] Obtain intermediate frequency domain data;

[0155] Multiply the intermediate frequency domain data and the frequency domain error to obtain the convergence compensation value.

[0156] Understandably, the filter is trained using the following steps:

[0157] The input signal is processed using a frequency domain filter with first model parameters to obtain first frequency domain equalized signal data;

[0158] Calculate the training frequency domain error between the first frequency domain equalized signal data and the preset reference signal;

[0159] The second convergence compensation value is determined based on the training frequency domain error;

[0160] Update the first model parameters of the frequency domain filter based on the second convergence compensation value;

[0161] Repeat the training steps until the training frequency domain error meets the convergence requirement.

[0162] It should be noted that the convergence requirement can be set according to actual needs. For example, the convergence requirement may be that the training frequency domain error is greater than a set error threshold, or that a preset number of training iterations or training duration is reached.

[0163] It should be noted that during training, a set of training data sequences to be transmitted, known to both the transmitting terminal 100 and the receiving terminal 200, and a corresponding reference signal for frequency domain filter compensation are constructed. At this time, referring to the actual service processing, the receiving terminal 200 obtains the training time-domain signal data corresponding to the training data, removes the unique header from the training time-domain signal data, constructs a training time-domain intermediate data block based on the removed header, and uses the training frequency-domain intermediate data obtained by frequency domain conversion of the training time-domain intermediate data block as the input signal. This input signal, along with the reference signal, is used to train the frequency domain filter.

[0164] It should be noted that in some embodiments, due to the instability of channel quality, the frequency domain filter is trained in real time during transmission. After training, the intermediate frequency domain data representing the service data is equalized based on the trained frequency domain filter. It should also be noted that in some embodiments, the start condition for real-time training of the frequency domain filter can be set to the channel quality change between two adjacent time periods exceeding a preset quality threshold. In other embodiments, the start condition can be set to iterative training every one channel transmission period, with the iterative training duration set to a first preset duration. When the training time reaches the first preset duration or the frequency domain filter meets the convergence requirement, the training of the frequency domain filter for the current channel transmission period is stopped, and the intermediate time domain data blocks representing the real service data are processed in the remaining duration of the current channel transmission period, thus allowing the frequency domain filter to be trained periodically. Those skilled in the art can selectively configure these settings according to actual needs.

[0165] For example, taking a frequency domain filter period as an example, and updating the first model parameters according to the strength of phase noise, with the reference signal including a reference signal under weak phase noise and a reference signal under strong phase noise, when within the first preset duration of the current channel transmission period, under weak phase noise, the reference... Figure 6 As shown in (a), when the first training frequency domain equalization signal data is obtained from the input signal after passing through the frequency domain filter, the training frequency domain error is obtained by subtracting the first training frequency domain equalization signal data from the reference signal under weak phase noise. The convergence compensation value is then updated based on the training error. Under strong phase noise, the reference signal is used... Figure 6 As shown in (b), when the first training frequency domain equalization signal data output by the input signal through the frequency domain filter is obtained and the first training equalization time domain signal data is obtained after time domain conversion, the first training equalization time domain signal data is subtracted from the reference signal under strong phase noise to obtain the training time domain error, and the training time domain error is converted into the frequency domain to obtain the convergence compensation value.

[0166] Understandably, after obtaining the target time-domain signal data corresponding to the original signal data, the signal receiving method also includes:

[0167] Remove unique words from the second equalized time-domain signal data;

[0168] Based on the removed second equalization time-domain signal data, the target signal data corresponding to the original signal data is obtained.

[0169] For example, refer to Figure 6 As shown, the original signal data is synchronized to obtain time-domain signal data. After removing the unique word header from the time-domain signal data, dispersion compensation and matched filtering can be selectively performed. The matched-filtered time-domain signal data is then converted from serial to parallel (S / P) and enters the equalization module. The equalization module outputs the second equalized time-domain signal data. After removing the unique word from the second equalized time-domain signal data and performing P / S (i.e., parallel-to-serial conversion), symbol decoding is performed to obtain the target signal data.

[0170] It is understandable that the first preset length is greater than or equal to the sum of the channel impulse response length and the dispersion length;

[0171] Frequency domain equalization is performed on the intermediate time-domain data block to obtain the first equalized time-domain signal data corresponding to the original signal data, including:

[0172] The undispersion compensated intermediate time-domain data block is subjected to frequency-domain equalization to obtain the first equalized time-domain signal data corresponding to the original signal data.

[0173] It should be noted that when the first preset length is greater than or equal to the sum of the channel impulse response length and the dispersion length, it can achieve joint compensation for dispersion and mode coupling. In this case, there is no need to add a separate dispersion compensation module, thereby further reducing complexity. Therefore, in practical applications, the first preset length can be adjusted to cover both the dispersion length and the channel impulse response length, so that the unique character can cover both mode coupling and dispersion effects.

[0174] It should be noted that when using dispersion compensation, the dispersion length is N. CD For example, when a separate dispersion compensation module is needed for dispersion compensation, related technologies typically use the overlap-preservation method, which increases the complexity by 2log2(N). CD Using unique characters, when these characters can cover both pattern coupling and dispersion effects, there is no need to add a separate dispersion compensation module. Therefore, 2log2(N) CD The complexity of the receiver can be reduced, thus simplifying the receiver's structure.

[0175] It should be noted that in some embodiments, the first preset length can be selectively set according to whether the receiver includes a dispersion detection module for auxiliary dispersion compensation, thereby satisfying the dispersion compensation requirements. For example, when the receiver does not include a dispersion detection module, the first preset length is set to be greater than or equal to the sum of the channel impulse response length and the dispersion length. When the receiver includes a dispersion detection module, the first preset length can be set to be greater than the channel impulse response length and less than the sum of the channel impulse response length and the dispersion length.

[0176] Understandably, the first preset length is greater than or equal to the length of the channel impulse response, and less than the sum of the length of the channel impulse response and the dispersion length.

[0177] The intermediate time-domain data block is subjected to frequency-domain equalization to obtain the first equalized time-domain signal data corresponding to the original signal data, which also includes:

[0178] Dispersion compensation processing is performed on intermediate data blocks in the time domain;

[0179] The dispersion-compensated result is then subjected to frequency domain equalization to obtain the first equalized time-domain signal data corresponding to the original signal data.

[0180] It should be noted that dispersion compensation is performed through a separate dispersion compensation module.

[0181] It is understood that, according to the signal transmission method provided in this application, a transmitting terminal 100 of an optical communication system is applied. The optical communication system includes a transmitting terminal 100 and a receiving terminal 200, and the transmitting terminal 100 and the receiving terminal 200 are communicatively connected, as shown below. Figure 10 As shown, the signal transmission method includes:

[0182] Step S200: Obtain the data sequence to be sent, which includes multiple symbol data;

[0183] Step S210: For every second preset length of symbol data, insert a unique word of the first preset length into the data sequence to be transmitted to generate original signal data including multiple data groups with a first period length. The first preset symbol length is greater than or equal to the length of the channel impulse response, and the first period length is equal to the sum of the first preset length and the second preset length.

[0184] Step S220: Send the original signal data to the receiving terminal 200 so that the receiving terminal 200 can perform the above-described signal receiving method.

[0185] Therefore, by obtaining time-domain signal data with a period of two preset lengths and inserting a unique word of a first preset length into the data sequence to be transmitted in the transmitting terminal 100, the receiving terminal 200 can construct intermediate time-domain data blocks after removing the unique word header from the time-domain signal data. This transforms the linear convolution between the original signal data and the channel impulse response into a circular convolution of multiple intermediate time-domain data blocks, thereby achieving full-process frequency-domain processing for channel equalization. Compared to related technologies, the embodiments of this application are mode-independent, only requiring consideration of the unique word length and the division of intermediate time-domain data blocks, resulting in lower complexity. Therefore, the embodiments of this application further improve the communication quality of the optical communication system while maintaining transmission capacity.

[0186] For example, see below. Figure 3 , Figure 4 , Figure 6 as well as Figure 10 The optical signal transmission and processing process of the optical communication system described in this application is as follows:

[0187] Reference Figure 3 and Figure 10 As shown, in the transmitting terminal 100, a data sequence to be transmitted is generated, so that the symbol data can be divided into multiple data segments of a second preset length, and the data is modulated, UW is added and matched filtering is performed to obtain the original signal data. The original signal data and the beam emitted by the laser 110 are modulated by the coherent optical modulator 130 to obtain the modulated optical signal, and output to the transmission channel 300.

[0188] At this time, refer to Figure 3 , Figure 6 and Figure 4As shown, the receiving terminal 200 receives the multi-modulated optical signals decomposed by the multiplexing unit 310 through the optical receiver 210, performs data synchronization to obtain time-domain signal data, and removes the UW header from the time-domain signal data to construct multiple time-domain intermediate data blocks. When the first preset length is greater than or equal to the length of the channel impulse response, and less than the sum of the length of the channel impulse response and the dispersion length, dispersion compensation, matched filtering, and serial-to-parallel conversion are performed sequentially before the data is input to the equalization module for frequency-domain equalization processing. When the first preset length is greater than or equal to the sum of the length of the channel impulse response and the dispersion length, matched filtering and serial-to-parallel conversion are performed on the time-domain intermediate data blocks before the data is input to the equalization module for frequency-domain equalization processing.

[0189] In the equalization module, refer to Figure 6 As shown in (a), the intermediate time-domain data block y is output as intermediate frequency-domain data Y via FFT. The intermediate frequency-domain data Y is then filtered by a frequency-domain filter to obtain the first frequency-domain equalized signal data X. The first frequency-domain equalized signal data X is then output as first equalized time-domain signal data x via IFFT. The first equalized time-domain signal data x is then subjected to phase noise compensation by a PLL to obtain the second equalized time-domain signal data. After the second time-domain equalized signal data is used for decision-making, the target time-domain signal data is output. Target time domain signal data FFT outputs reference frequency domain signal data At this time, the reference frequency domain signal data Subtracting the first frequency domain equalization signal data X from the first frequency domain equalization signal data X yields the frequency domain error. Multiplying this frequency domain error by the intermediate frequency domain data Y yields the first compensation amount, thereby updating the first model parameters W of the frequency domain filter. k+1 =W k +E k Y k Among them, W k E represents the initial model parameters before the update. k This represents frequency domain error. In cases of strong phase noise, such as... Figure 6 As shown in (b), the intermediate time-domain data block y is output as intermediate frequency-domain data Y via FFT. The intermediate frequency-domain data Y is then filtered by a frequency-domain filter to obtain the first frequency-domain equalized signal data X. The first frequency-domain equalized signal data X is then output as first equalized time-domain signal data x via IFFT. The first equalized time-domain signal data x is then subjected to phase noise compensation by a PLL to obtain the second equalized time-domain signal data. The second time-domain equalized signal data is then used to determine the target time-domain signal data. The target time-domain signal data is then subjected to phase noise addition to obtain the reference time-domain signal data. At this time, refer to the time-domain signal data Subtracting the first equalized time-domain signal data x from the time-domain data yields the time-domain error. The time-domain error is then processed by FFT to output the frequency-domain error E. kThe first compensation amount is calculated by multiplying the frequency domain error by the intermediate frequency domain data Y, thereby updating the first model parameter W of the frequency domain filter. k+1 =W k +E k Y k At this point, the equalization module outputs the second equalization time-domain data.

[0190] After obtaining the second equalized time-domain data output by the equalization module, the receiving terminal 200 sequentially performs UW removal, P / S decoding, and symbol decoding on the second equalized time-domain data to obtain the target signal data.

[0191] Reference Figure 1 As shown, this application also provides an optical communication system, which includes:

[0192] Sending terminal 100;

[0193] Transmission channel 300 is used to transmit modulated optical signals;

[0194] Receiver terminal 200;

[0195] The transmitting terminal 100 is used for:

[0196] Obtain the data sequence to be sent, which includes multiple symbol data;

[0197] For every second preset length of symbol data, a unique word of the first preset length is inserted into the data sequence to be transmitted to generate original signal data including multiple data groups with a first period length. The first preset symbol length is greater than or equal to the length of the channel impulse response, and the first period length is equal to the sum of the first preset length and the second preset length.

[0198] Send the original signal data to the receiving terminal 200;

[0199] The receiving terminal 200 is used for:

[0200] Receive time-domain signal data; wherein, the time-domain signal data is obtained by transmitting the original signal data sent by the transmitting terminal 100 through the transmission channel 300;

[0201] Based on the first preset length, remove the unique word header of the time-domain signal data;

[0202] Based on the length of the first period, the time-domain signal data after removing the unique word header is divided into multiple time-domain intermediate data blocks, so that each time-domain intermediate data block corresponds to a circular convolution of a data group and the channel impulse response.

[0203] Frequency domain equalization is performed on the intermediate time-domain data block to obtain the first equalized time-domain signal data corresponding to the original signal data.

[0204] For example, suppose the data sequence to be transmitted is x = [x0, x1, x2, x3, x4, x5], consisting of 6 symbols. The first preset length is 1, and the second preset length is 3. Then the first cycle length is 4. In this case, the data sequence to be transmitted after inserting the unique word is x. UW =[uw1,x0,x1,x2,uw1,x3,x4,x5], where, x 1 =[uw1,x0,x1,x2]、x 2 = [uw1, x3, x4, x5] are data groups. When the channel impulse response h = [h0, h1], the time-domain signal data y obtained after the original signal data passes through the channel response is:

[0205]

[0206] Correspondingly, the UW header of the time-domain signal data y is the data located at the first preset length, i.e., h0uw1. At this time, the time-domain signal data after removing the UW header...

[0207] At this time, refer to Figure 2 The data structure of the time-domain signal data shown can be considered as the concatenation of the results of circular convolutions of each data group with the channel impulse response, i.e., it is equal to the concatenation of C1 and C2, where C1 is x. 1 The result of the circular convolution of [uw1,x0,x1,x2] and h = [h0,h1], where C2 is x 2 The result of the circular convolution of [uw1,x3,x4,x5] and h = [h0,h1]. At this point, refer to... Figure 2 As shown, by dividing the data proportionally according to the length of the first cycle, two intermediate time-domain data blocks can be obtained. One intermediate time-domain data block is FFT1 = [h1uw1 + h0x0, h1x0 + h0x1, h1x1 + h0x2, h1x2 + h0uw1], and the other intermediate time-domain data block is FFT2 = [h1uw1 + h0x3, h1x3 + h0x4, h1x4 + h0x5, h1x5 + h0uw1]. The circular convolution in the time domain corresponds to the product of the intermediate time-domain data block and the channel response in the frequency domain. That is, the intermediate time-domain data block Y, the channel response H, and the data group X in the frequency domain have the following relationship: Y = HX. Therefore, when the filter response W = 1 / H, frequency domain equalization can be achieved using simple multiplication in the frequency domain, and the time-domain signal data of each mode or fiber core can be processed independently, thereby reducing the complexity of channel equalization.

[0208] Therefore, the optical communication system of this application inserts a unique word of a first preset length into the middle of the data sequence to be transmitted by the transmitting terminal 100 at a period of a second preset length, thereby obtaining the time-domain signal data received by the receiving terminal 200. After removing the unique word header from the time-domain signal data, a time-domain intermediate data block is constructed. This transforms the linear convolution between the original signal data and the channel impulse response into a circular convolution of multiple time-domain intermediate data blocks, thus enabling frequency-domain processing of the entire channel equalization process. Compared with related technologies, the embodiments of this application are mode-independent, only requiring consideration of the length of the unique word and the division of the time-domain intermediate data block, resulting in lower complexity. Therefore, the embodiments of this application further improve the communication quality of the optical communication system while maintaining transmission capacity.

[0209] Understandably, referring to Figure 3 As shown, the transmission channel 300 includes:

[0210] Multiplexing unit 310 is used to combine modulated optical signals of different wavelengths from transmitting terminal 100;

[0211] Optical fiber 320 is connected to multiplexing unit 310 and is used to transmit the combined modulated optical signal. Optical fiber 320 is a multimode fiber or a few-mode fiber.

[0212] The demultiplexing unit 330 is connected to the optical fiber 320 and is used to receive the merged modulated optical signal transmitted by the optical fiber 320, and to separate and process the merged modulated optical signal before sending it to the receiving terminal 200.

[0213] It should be noted that the multiplexing unit 310 can be configured as a mode coupler or a fiber core coupler. The modulated optical signal output by the transmitting terminal 100 is coupled in the optical fiber 320 after passing through the multiplexing unit 310. It should also be noted that the demultiplexing unit 330 can be configured as a mode decoupler or a fiber core decoupler. The demultiplexing unit 330 separates the modulated optical signals of different modes (i.e., different wavelengths) transmitted in the optical fiber 320, and the receiving terminal 200 completes the reception and parsing of the separated modulated optical signals.

[0214] For example, consider D modulated optical signals of different wavelengths entering transmission channel 300. (Refer to...) Figure 3 As shown, the D-channel modulated optical signals of different wavelengths enter the optical fiber 320 through the multiplexing unit 310 and are coupled in the optical fiber 320. At this time, the demultiplexing unit 330 separates the D-channel modulated optical signals of different wavelengths so that the receiving terminal 200 can perform coherent reception, and synchronize and analyze the received D-channel modulated optical signals.

[0215] It is understood that, in some embodiments, the transmitting terminal 100 of the optical communication system includes:

[0216] Laser 110 is used to emit a beam of light;

[0217] The first controller 120 is used to generate the original signal data;

[0218] Modulator 130 is used to modulate the beam emitted by laser 110 according to the original signal data to generate a modulated optical signal and send it to receiving terminal 200.

[0219] The first controller 120 can obtain the original signal data by performing the following steps:

[0220] Obtain the data sequence to be sent, which includes multiple symbol data;

[0221] For every second preset length of symbol data, a unique word of the first preset length is inserted into the data sequence to be transmitted to generate original signal data including multiple data groups with a first period length. The first preset symbol length is greater than or equal to the length of the channel impulse response, and the first period length is equal to the sum of the first preset length and the second preset length.

[0222] The original signal data is sent to the receiving terminal 200, so that the receiving terminal 200 removes the unique word header of the time-domain signal data corresponding to the original signal data, constructs multiple time-domain intermediate data blocks, and performs channel equalization processing on the time-domain intermediate data blocks to obtain the first equalized time-domain signal data corresponding to the original signal data.

[0223] It should be noted that in some embodiments, the first controller 120 includes a redundant codeword addition module, thereby ensuring that the data sequence to be transmitted can be divided into multiple symbol data of the same second preset length, so that the original signal data can be composed of multiple data groups with a first period length.

[0224] It should be noted that the modulator 130 can be configured as a coherent optical modulator 130.

[0225] For example, refer to Figure 3 As shown, after the first controller 120 acquires the data sequence to be transmitted, it sequentially performs data modulation, UW addition, and matched filtering to obtain multiple original signal data, including multiple data groups with a first period length. The original signal data is then used by the laser 110 and the modulator 130 to generate a modulated optical signal that can be transmitted in the transmission channel 300.

[0226] It should be noted that the transmitting terminal 100 in this embodiment can be applied as follows: Figure 1 The transmitting terminal 100 in the system architecture of the illustrated embodiment performs, as shown in the example. Figure 10 The signal transmission method described above, in this embodiment, the transmitting terminal 100 and such Figure 1The system architecture shown in the embodiment includes a transmitting terminal 100 and a transmitting terminal 100, as well as a transmitting terminal 100. Figure 10 The signal transmission methods described herein share the same inventive concept, and therefore these embodiments share the same implementation principle and technical effect, which will not be detailed here.

[0227] It is understood that, in some embodiments, the receiving terminal 200 of the optical communication system includes:

[0228] Optical receiver 210 is used to receive modulated optical signals from transmitting terminal 100 and convert the modulated optical signals into time-domain signal data;

[0229] The second controller 220 is communicatively connected to the optical receiver 210 and is used to receive time-domain signal data and process the time-domain signal data as follows:

[0230] Receive time-domain signal data; wherein, the time-domain signal data is obtained by transmitting the original signal data sent by the transmitting terminal 100 through the transmission channel 300, and the time-domain signal data is equal to the linear convolution of the original signal data and the channel impulse response of the transmission channel 300; the original signal data includes multiple data groups with a first period length, each data group consisting of a unique word of a first preset length and symbol data of a second preset length;

[0231] Based on the first preset length, remove the unique word header of the time-domain signal data;

[0232] Based on the length of the first period, the time-domain signal data after removing the unique word header is divided into multiple time-domain intermediate data blocks, so that each time-domain intermediate data block corresponds to a circular convolution of a data group and the channel impulse response.

[0233] Frequency domain equalization is performed on the intermediate time-domain data block to obtain the first equalized time-domain signal data corresponding to the original signal data.

[0234] It should be noted that, referring to Figure 5As shown, in some embodiments, the second controller 220 includes a data synchronization module, a unique word header removal module, a matched filtering module, a serial-to-parallel conversion module, an equalization module, a unique word removal module, a parallel-to-serial conversion module, and a symbol decoding module. The data synchronization module synchronizes the received multi-channel modulated optical signals to obtain multiple time-domain signal data. The unique word header removal module removes unique word headers from the time-domain signal data according to a first preset length and divides the time-domain signal data after unique word header removal according to a first period length to construct multiple intermediate time-domain data blocks. The equalization module performs frequency domain equalization on the intermediate time-domain data blocks to obtain first equalized time-domain signal data corresponding to the original signal data, and outputs second equalized time-domain signal data after phase noise compensation based on the first equalized time-domain signal data. The unique word removal module removes unique words from the output second equalized time-domain signal data of the equalization module to obtain data to be decoded. The parallel-to-serial conversion module performs parallel-to-serial conversion on the data to be decoded, and the symbol decoding module decodes the parallel-to-serial converted data to obtain the target signal data.

[0235] It should be noted that the receiving terminal 200 in this embodiment can be applied as follows: Figure 1 The receiving terminal 200 in the system architecture of the illustrated embodiment performs, as shown in the example. Figure 4 The signal receiving method described herein, in this embodiment, includes the receiving terminal 200 and, as shown... Figure 1 The receiving terminal 200 in the system architecture of the illustrated embodiment and as shown Figure 4 The signal receiving methods described herein share the same inventive concept, and therefore these embodiments share the same implementation principle and technical effect, which will not be detailed here.

[0236] An embodiment of this application also provides a computer-readable storage medium storing computer-executable instructions for performing the methods provided in any embodiment of this application.

[0237] An embodiment of this application also provides a computer program product, including a computer program or computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer program or computer instructions from the computer-readable storage medium and executes the computer program or computer instructions, causing the computer device to perform the method provided in any embodiment of this application.

[0238] The system architecture and application scenarios described in this application are intended to more clearly illustrate the technical solutions of this application and do not constitute a limitation on the technical solutions provided in this application. Those skilled in the art will understand that as system architectures evolve and new application scenarios emerge, the technical solutions provided in this application are also applicable to similar technical problems.

[0239] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0240] In hardware implementations, the division between functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0241] The terms “component,” “module,” “system,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, or a computer. As illustrated, applications running on computing devices and computing devices can both be components. One or more components may reside in a process or execution thread, and components may be located on a single computer or distributed among two or more computers. Furthermore, these components can be executed from various computer-readable media on which various data structures are stored. Components can communicate, for example, via local or remote processes based on signals having one or more data packets—e.g., data from two components interacting with another component between a local system, a distributed system, or a network, such as the Internet interacting with other systems via signals.

[0242] The above description, with reference to the accompanying drawings, illustrates some embodiments of this application, but does not limit the scope of the invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and spirit of this invention should be considered within the scope of this application.

Claims

1. A signal receiving method, characterized in that, A receiving terminal used in an optical communication system, the optical communication system including a transmitting terminal and the receiving terminal, the transmitting terminal being communicatively connected to the receiving terminal, the signal receiving method including: Receive time-domain signal data; wherein the time-domain signal data is obtained by transmitting the original signal data sent by the transmitting terminal through the transmission channel, and the time-domain signal data is equal to the linear convolution of the original signal data and the channel impulse response of the transmission channel; the original signal data includes multiple data groups with a first period length, each data group consisting of a unique word of a first preset length and symbol data of a second preset length; Based on the first preset length, remove the unique word header of the time-domain signal data; Based on the first period length, the time-domain signal data after removing the unique word header is divided to construct multiple time-domain intermediate data blocks, so that each time-domain intermediate data block corresponds to a data group and the circular convolution of the channel impulse response. The intermediate time-domain data block is subjected to frequency-domain equalization to obtain the first equalized time-domain signal data corresponding to the original signal data. The process of performing frequency domain equalization on the intermediate time-domain data block to obtain first equalized time-domain signal data corresponding to the original signal data includes: Perform a Fourier transform on each of the aforementioned time-domain intermediate data blocks to obtain the frequency-domain intermediate data; Channel equalization processing is performed on the intermediate frequency data using a frequency domain filter with first model parameters to obtain the first frequency domain equalized signal data corresponding to the intermediate frequency data. The method further includes: Perform an inverse Fourier transform on the first frequency domain equalized signal data to obtain the first equalized time domain signal data corresponding to the original signal data; Phase noise compensation is performed on the first equalized time-domain signal data to obtain the second equalized time-domain signal data; The second equalized time-domain signal data is used to make a decision to obtain the target time-domain signal data corresponding to the original signal data; The frequency domain error is determined based on the first frequency domain equalization signal data and the target time domain signal data; Based on the frequency domain error, determine the convergence compensation value for channel equalization processing; The first model parameters of the frequency domain filter are updated according to the convergence compensation value, so that the frequency domain filter with updated first model parameters performs channel equalization processing on the next frequency domain intermediate data to obtain the corresponding first frequency domain equalized signal data.

2. The signal receiving method according to claim 1, characterized in that, The step of removing the unique word header of the time-domain signal data according to the first preset length includes: Obtain the length of the first sequence of the unique character; Remove the data located at the first sequence length position before the time-domain signal data; Based on the first period length, the time-domain signal data after removing the unique word header is divided into multiple time-domain intermediate data blocks, including: The removed time-domain signal data is divided according to the first period length to obtain multiple time-domain intermediate data blocks with the same length as the data group.

3. The signal receiving method according to claim 1, characterized in that, The step of determining the frequency domain error based on the first frequency domain equalization signal data and the target time domain signal data includes: Calculate the reference frequency domain signal data after Fourier transforming the target time domain signal data; The frequency domain error is obtained by calculating the difference between the reference frequency domain signal data and the first frequency domain equalization signal data.

4. The signal receiving method according to claim 1, characterized in that, The step of determining the frequency domain error based on the first frequency domain equalization signal data and the target time domain signal data includes: Calculate the time-domain signal error between the target time-domain signal data and the first equalized time-domain signal data; The frequency domain error is obtained by performing a Fourier transform on the time-domain signal error.

5. The signal receiving method according to claim 1, characterized in that, The step of determining the frequency domain error based on the first frequency domain equalization signal data and the target time domain signal data includes: Obtain the phase noise compensation value of the first equalized time-domain signal data for phase noise compensation; The phase noise compensation value is applied to the target time-domain signal data to obtain reference time-domain signal data. Calculate the time-domain signal error between the reference time-domain signal data and the first equalized time-domain signal data; The frequency domain error is obtained by performing a Fourier transform on the time-domain signal error.

6. The signal receiving method according to claim 1, characterized in that, The step of determining the convergence compensation value for channel equalization processing based on the frequency domain error includes: Obtain the intermediate frequency domain data; The convergence compensation value is obtained by multiplying the intermediate frequency domain data and the frequency domain error.

7. The signal receiving method according to claim 1, characterized in that, The filter is trained using the following training steps: The input signal is processed using a frequency domain filter with first model parameters to obtain first frequency domain equalized signal data; Calculate the training frequency domain error between the first frequency domain equalized signal data and the preset reference signal; The second convergence compensation value is determined based on the training frequency domain error; The first model parameters of the frequency domain filter are updated according to the second convergence compensation value; The training steps are repeated until the training frequency domain error meets the convergence requirement.

8. The signal receiving method according to claim 1, characterized in that, After obtaining the target time-domain signal data corresponding to the original signal data, the signal receiving method further includes: Remove unique words from the second equalized time-domain signal data; Based on the removed second equalized time-domain signal data, the target signal data corresponding to the original signal data is obtained.

9. The signal receiving method according to claim 1, characterized in that, The first preset length is greater than or equal to the sum of the channel impulse response length and the dispersion length; The step of performing frequency domain equalization on the intermediate time-domain data block to obtain the first equalized time-domain signal data corresponding to the original signal data includes: The undispersion-compensated intermediate time-domain data block is subjected to frequency-domain equalization to obtain the first equalized time-domain signal data corresponding to the original signal data.

10. The signal receiving method according to claim 1, characterized in that, The first preset length is greater than or equal to the length of the channel impulse response, and less than the sum of the length of the channel impulse response and the dispersion length; The step of performing frequency domain equalization processing on the intermediate time-domain data block to obtain the first equalized time-domain signal data corresponding to the original signal data further includes: Dispersion compensation processing is performed on the intermediate data block in the time domain; The dispersion-compensated result is then subjected to frequency domain equalization to obtain the first equalized time-domain signal data corresponding to the original signal data.

11. A signal transmission method, characterized in that, A transmitting terminal used in an optical communication system, the optical communication system including the transmitting terminal and a receiving terminal, the transmitting terminal being communicatively connected to the receiving terminal, the signal transmission method including: Obtain a data sequence to be sent, the data sequence to be sent including multiple symbol data; For every second preset length of symbol data, a unique word of a first preset length is inserted into the data sequence to be transmitted to generate original signal data including multiple data groups with a first period length, wherein the first preset length is greater than or equal to the length of the channel impulse response, and the first period length is equal to the sum of the first preset length and the second preset length; The original signal data is sent to the receiving terminal so that the receiving terminal performs the signal receiving method as described in claim 1.

12. A transmitting terminal for an optical communication system, characterized in that, include: A laser is used to emit a beam of light; A first controller is configured to generate original signal data by executing the signal transmission method as described in claim 11; A modulator is used to modulate the beam emitted by the laser according to the original signal data to generate a modulated optical signal that is sent to the receiving terminal.

13. A receiving terminal for an optical communication system, characterized in that, include: An optical receiver is used to receive modulated optical signals from a transmitting terminal and convert the modulated optical signals into time-domain signal data. The second controller is communicatively connected to the optical receiver and is used to receive the time-domain signal data and process the time-domain signal data using the signal receiving method as described in any one of claims 1 to 10.

14. An optical communication system, characterized in that, include: The transmitting terminal as described in claim 12; Transmission channel, used to transmit modulated optical signals; The receiving terminal as described in claim 13.

15. The optical communication system according to claim 14, characterized in that the transmission channel comprises: A multiplexing unit is used to combine modulated optical signals of different wavelengths from the transmitting terminal; An optical fiber, connected to the multiplexing unit, is used to transmit the combined modulated optical signal, wherein the optical fiber is a multimode optical fiber or a few-mode optical fiber; The demultiplexing unit is connected to the optical fiber and is used to receive the combined modulated optical signal transmitted through the optical fiber, and to separate the combined modulated optical signal before sending it to the receiving terminal.

16. A storage medium, characterized in that, It includes storing computer-executable instructions for performing the signal receiving method as described in any one of claims 1 to 10, and / or the signal transmitting method as described in claim 11.

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