WO2021027830A1

WO2021027830A1 - Signal processing method, receiver and digital processing chip

Info

Publication number: WO2021027830A1
Application number: PCT/CN2020/108613
Authority: WO
Inventors: 刘玲; 肖治宇; 李良川
Original assignee: 华为技术有限公司
Priority date: 2019-08-15
Filing date: 2020-08-12
Publication date: 2021-02-18
Also published as: CN112398765A; CN112398765B

Abstract

Disclosed are a signal processing method, a receiver and a digital processing chip, wherein same are used for reducing the complexity of sequence detection. The method in the embodiments of the present application comprises: a receiver acquiring a service signal to be processed that has intersymbol interference (ISI); then, the receiver determining first information transmitted by an information node set to an ISI check node set, wherein there is a correlation between each ISI check node and N information nodes in the information node set, N is an integer greater than or equal to one, and N is positively correlated with a memory span of the ISI; next, the receiver determining, according to the first information, second information transmitted by the ISI check node set to the information node set; and then, summing up the second information to obtain first output information for judgment.

Description

A signal processing method, receiver and digital processing chip

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on August 15, 2019, with the application number 201910754935. 1, the invention title is "a signal processing method, receiver and digital processing chip", the entire content of which is by reference Incorporated in this application.

Technical field

This application relates to the field of communication technology, and in particular to a signal processing method, receiver and digital processing chip.

Background technique

Coherent receivers with limited bandwidth are affected by intersymbol interference (ISI), resulting in system performance degradation. For this reason, a post filter, a sequence detector, and a forward error correction (FEC) module can be used in a coherent receiver to improve system performance.

Among them, the sequence detector and the FEC module can further improve the system performance through soft information iteration. Specifically, the output signal of the post filter is input to the sequence detector. The sequence detector is used to eliminate the influence of ISI and output soft information to the FEC module. After the FEC module is processed, the soft information is output to the sequence detector to complete the sequence detector and Soft information iteration between FEC modules.

One implementation scheme of the current sequence detection is to use the BCJR algorithm to eliminate the impact of ISI. Taking the ISI signal with a channel memory length of m and a transmission bit number of b as an example, the corresponding state number at the current moment is 2 ^b(m-1) , The complexity of a sequence detection has an exponential relationship with the channel memory length m. As the channel memory length m increases, the complexity of the iteration increases exponentially, resulting in higher sequence detection complexity.

Summary of the invention

The embodiments of the present application provide a signal processing method, a receiver, and a digital processing chip to reduce the complexity of sequence detection.

In the first aspect, an embodiment of the present application provides a signal processing method, which includes the following steps.

The receiver obtains the service signal with ISI to be processed. After that, the receiver determines the first information transmitted from the set of information nodes to the set of ISI check nodes, where there is a first correspondence between the set of information nodes and the set of ISI check nodes, and the first correspondence includes the set of ISI check nodes The correspondence between each ISI check node and N information nodes in the information node set and the correspondence between each information node in the information node set and at least one ISI check node, N is an integer greater than or equal to 1, and N It is positively related to the memory length of ISI. The first information includes the first soft information transmitted by each information node to at least one ISI check node that has a corresponding relationship with each information node. The first soft information includes the first probability and the second The logarithm of the probability ratio. The first probability is the probability that the original signal corresponding to the service signal is equal to 0, and the second probability is the probability that the original signal is equal to 1. Next, the receiver determines the second information transmitted from the set of ISI check nodes to the set of information nodes according to the first information, and the second information includes each ISI check node to N that has a first corresponding relationship with each ISI check node. The second soft information transmitted by an information node, where the second soft information includes the logarithm of the ratio of the first probability to the second probability under the premise that the service signal is used as the input. Furthermore, the second information is summed to obtain the first output information for decision.

In this embodiment, sequence detection is performed by exchanging information between the set of information nodes and the set of ISI check nodes, thereby eliminating the influence of ISI, and each ISI check node corresponds to N information nodes, that is, ISI calibration There is a linear correspondence between the set of verification nodes and the set of information nodes. As the memory length of ISI increases, the complexity of information transmission between the set of ISI check nodes and the set of information nodes will only increase linearly, reducing the sequence The complexity of detection.

Optionally, in some possible implementation manners, the ISI check node set includes M groups of ISI check nodes, where M is an integer greater than 1, and each group of ISI check nodes includes at least one ISI check node, according to the first information It is determined that the second information transmitted from the set of ISI check nodes to the set of information nodes includes:

The receiver sequentially determines, according to the first information, M groups of sub-information transmitted by the M groups of ISI check nodes to the information nodes corresponding to the M groups of ISI check nodes, and determines the second information according to the M groups of sub-information.

In this embodiment, part of the ISI check nodes can be selected from the set of ISI check nodes each time, and the sub-information transmitted by the selected ISI check node to the corresponding information node can be determined in turn. These sub-information The set of is the second information. In this way, updating the ISI check nodes in batches can further reduce the complexity of sequence detection and speed up convergence.

Optionally, in some possible implementation manners, after determining the second information transmitted by the ISI check node set to the information node set according to the first information, the method further includes:

The receiver determines the third information transmitted from the set of information nodes to the set of ISI check nodes based on the second information, and then determines the fourth information transmitted from the set of ISI check nodes to the set of information nodes based on the third information, and then sums the fourth information Obtain the second output information for decision.

In this embodiment, the information transmitted from the set of ISI check nodes to the set of information nodes depends on the information transmitted from the set of information nodes to the set of ISI check nodes in the previous step. Similarly, the set of information nodes transmits information to the set of ISI check nodes. Depends on the information transmitted from the ISI check node set to the information node set in the previous step. That is, the ISI check node set and the information node set can exchange information in an iterative manner, and output information for decision after the iteration ends. The iteration makes the sequence detection effect better and improves the system performance of the receiver.

Optionally, in some possible implementation manners, there is a second correspondence between the set of information nodes and the set of FEC check nodes, and after summing the second information to obtain the first output information for decision, the method further includes:

The receiver determines the fifth information transmitted by the FEC check node set to the information node set according to the first output information, and then determines the sixth information transmitted by the information node set to the ISI check node set according to the second information and the fifth information, and then Determine the seventh information transmitted from the ISI check node set to the information node set according to the sixth information, and then sum the fifth information and the seventh information to obtain the third output information used for decision.

In this embodiment, in addition to sequence detection, the receiver will also perform FEC verification. The soft information output after sequence detection is used for FEC verification, and the soft information output after FEC verification is used for sequence detection. Serial iteration between sequence detection and FEC verification. The combination of sequence detection and FEC verification can further improve the system performance of the receiver.

Optionally, in some possible implementation manners, there is a second correspondence between the set of information nodes and the set of FEC check nodes, and after summing the fourth information to obtain the second output information for decision, the method further includes:

The receiver determines the eighth information transmitted by the FEC check node set to the information node set according to the second output information, and then determines the ninth information transmitted by the information node set to the ISI check node set according to the fourth information and the eighth information, and then Determine the tenth information transmitted by the ISI check node set to the information node set according to the ninth information, and then sum the eighth information and the tenth information to obtain the fourth output information used for decision.

In this embodiment, on the basis that sequence detection and FEC verification can be independently iterated, sequence detection and FEC verification can also be combined to implement serial iteration between sequence detection and FEC verification, so that the sequence The effect of detection and FEC verification is better, which improves the practicability of this solution.

Optionally, in some possible implementation manners, there is a second correspondence between the set of information nodes and the set of FEC check nodes, and after obtaining the service signal with ISI to be processed, the method further includes:

The receiver determines the eleventh information transmitted from the set of information nodes to the set of ISI check nodes and the set of FEC check nodes, and then determines the twelfth information transmitted from the set of ISI check nodes to the set of information nodes according to the eleventh information. The eleventh information determines the thirteenth information transmitted by the FEC check node set to the information node set, and then sums the twelfth information and the thirteenth information to obtain the fifth output information for decision.

In this embodiment, the receiver can perform sequence detection and FEC verification synchronously, that is, realize parallel iteration between sequence detection and FEC verification. Compared with the serial iteration between sequence detection and FEC verification, the information flow The sequence detection and FEC verification are no longer distinguished, which reduces the transmission of information and improves the efficiency of sequence detection and FEC verification.

Optionally, in some possible implementation manners, there is a second correspondence between the information node set and the forward error correction FEC check node set, the ISI check node set includes M groups of ISI check nodes, and M is greater than 1. Each group of ISI check nodes includes at least one ISI check node, and the second information transmitted from the set of ISI check nodes to the set of information nodes is determined according to the first information:

Determine the second information transmitted by the first group of ISI check nodes in the ISI check node set to the information node set according to the first information.

After summing the second information to obtain the first output information for decision, the method further includes:

According to the first output information, the fifth information transmitted from the FEC check node set to the information node set is determined. Determine the sixth information transmitted from the set of information nodes to the set of ISI check nodes according to the second information and the fifth information. Determine the seventh information transmitted by the second group of ISI check nodes in the ISI check node set to the information node set according to the sixth information. The fifth information and the seventh information are summed to obtain the third output information for decision.

In this embodiment, serial iteration can be performed between sequence detection and FEC verification, and the system performance of the receiver is improved by combining sequence detection and FEC verification. In addition, only part of the ISI check nodes are updated for each sequence detection, which can reduce the complexity of sequence detection and speed up convergence.

Optionally, in some possible implementation manners, there is a second correspondence between the set of information nodes and the set of FEC check nodes, and the set of ISI check nodes includes M groups of ISI check nodes, and M is an integer greater than 1, each The group ISI check node includes at least one ISI check node. After obtaining the service signal with ISI to be processed, the method further includes:

Determine the eleventh information transmitted from the set of information nodes to the set of ISI check nodes and the set of FEC check nodes. Determine the twelfth information transmitted by the first group of ISI check nodes in the ISI check node set to the information node set according to the eleventh information, and determine the tenth information transmitted by the FEC check node set to the information node set according to the eleventh information Three information. According to the twelfth information and the thirteenth information, determine the fourteenth information transmitted from the set of information nodes to the set of ISI check nodes. Determine the fifteenth information transmitted by the second group of ISI check nodes in the ISI check node set to the information node set according to the fourteenth information, and determine the tenth information transmitted by the FEC check node set to the information node set according to the fourteenth information Six information. The fifteenth information and the sixteenth information are summed to obtain the sixth output information for decision.

In this embodiment, parallel iterations can be performed between sequence detection and FEC verification, which improves the efficiency of sequence detection and FEC verification. In addition, only part of the ISI check nodes are updated for each sequence detection, which can reduce the complexity of sequence detection and speed up convergence.

Optionally, in some possible implementation manners, determining the second information transmitted from the ISI check node set to the information node set according to the first information includes:

It is determined according to the first information that the first group of ISI check nodes in the ISI check node set transmits the second information to the first group of information nodes in the information node set that has a first correspondence with the first group of ISI check nodes. The group of ISI check nodes includes at least one ISI check node, the first group of information nodes includes at least one information node, and the second information includes the second soft information transmitted by the first group of ISI check nodes to the first group of information nodes. The soft information includes the logarithm of the ratio of the first probability to the second probability based on the service signal.

After determining the second information transmitted by the ISI check node set to the information node set according to the first information, the method further includes:

If the soft information corresponding to the first information node in the first group of information nodes is less than the preset threshold, it is determined that the first information node transmits the first information node to the second group of ISI check nodes that have the first corresponding relationship with the first information node. Seventeen information, the second group of ISI check nodes includes at least one ISI check node. Determine the eighteenth information transmitted by the second group of ISI check nodes to the set of information nodes according to the seventeenth information;

If the soft information corresponding to the second information node in the first group of information nodes is greater than the preset threshold, it is determined that the second information node transmits to the third group of ISI check nodes that do not have the first corresponding relationship with the second information node. Nineteenth information, the third group of ISI check nodes includes at least one ISI check node. According to the nineteenth information, determine the twentieth information transmitted by the third group of ISI check nodes to the set of information nodes.

In this embodiment, only part of the ISI check nodes are updated each time the sequence is detected, which can reduce the complexity of the sequence detection and accelerate the convergence speed. It also provides a way to screen the ISI check nodes that need to be updated, which improves the practicability of the solution.

In the second aspect, an embodiment of the present application provides a digital processing chip. The chip includes a processor and a memory, and the memory and the processor are interconnected by wires. Instructions are stored in the memory, and the processor is used to execute the signal processing method in any one of the embodiments of the first aspect.

In a third aspect, an embodiment of the present application provides a receiver, including: a receiver front end and a digital processing chip, and the receiver front end and the digital processing chip are interconnected through a wire;

The front end of the receiver is used to convert the received optical signal into an electrical signal and transmit the electrical signal to the digital processing chip;

The digital processing chip is used to perform the following steps:

Obtain the to-be-processed service signal with inter-code crosstalk ISI;

Determine the first information transmitted from the set of information nodes to the set of ISI check nodes. There is a first correspondence between the set of information nodes and the set of ISI check nodes. The first correspondence includes each ISI check node in the set of ISI check nodes. Correspondence with the N information nodes in the information node set and the correspondence between each information node in the information node set and at least one ISI check node. N is an integer greater than or equal to 1, and the memory length of N and ISI is positive Related, the first information includes the first soft information transmitted by each information node to at least one ISI check node corresponding to each information node, and the first soft information includes the logarithm of the ratio of the first probability to the second probability, The first probability is the probability that the original signal corresponding to the service signal is equal to 0, and the second probability is the probability that the original signal is equal to 1;

Determine the second information transmitted by the ISI check node set to the information node set according to the first information, the second information includes the second information transmitted by each ISI check node to N information nodes corresponding to each ISI check node Soft information, the second soft information includes the logarithm of the ratio of the first probability to the second probability based on the service signal;

The second information is summed to obtain the first output information for decision.

Optionally, in some possible implementation manners, the set of ISI check nodes includes M groups of ISI check nodes, where M is an integer greater than 1, and each group of ISI check nodes includes at least one ISI check node;

The digital processing chip is specifically used for:

Sequentially determine, according to the first information, the M groups of sub-information transmitted by the M groups of ISI check nodes to the information nodes corresponding to the M groups of ISI check nodes;

The second information is determined according to the M groups of sub-information.

Optionally, in some possible implementation manners, after determining the second information transmitted by the ISI check node set to the information node set according to the first information, the digital processing chip is further used for:

Determining, according to the second information, the third information transmitted from the set of information nodes to the set of ISI check nodes;

Determining, according to the third information, the fourth information transmitted from the set of ISI check nodes to the set of information nodes;

The fourth information is summed to obtain the second output information for decision.

Optionally, in some possible implementation manners, there is a second correspondence between the set of information nodes and the set of forward error correction FEC check nodes. After the second information is summed to obtain the first output information for decision, Digital processing chips are also used for:

Determining, according to the first output information, the fifth information transmitted from the FEC check node set to the information node set;

Determining, according to the second information and the fifth information, the sixth information transmitted from the set of information nodes to the set of ISI check nodes;

Determine, according to the sixth information, the seventh information transmitted from the set of ISI check nodes to the set of information nodes;

The fifth information and the seventh information are summed to obtain the third output information for decision.

Optionally, in some possible implementation manners, there is a second correspondence between the set of information nodes and the set of FEC check nodes. After the fourth information is summed to obtain the second output information for decision, the digital processing chip also Used for:

Determine, according to the second output information, the eighth information transmitted from the FEC check node set to the information node set;

Determine, according to the fourth information and the eighth information, the ninth information transmitted from the set of information nodes to the set of ISI check nodes;

Determine the tenth information transmitted by the ISI check node set to the information node set according to the ninth information;

The eighth information and the tenth information are summed to obtain the fourth output information for decision.

Optionally, in some possible implementation manners, there is a second correspondence between the set of information nodes and the set of FEC check nodes. After obtaining the service signal with ISI to be processed, the digital processing chip is further used for:

Determine the eleventh information transmitted from the set of information nodes to the set of ISI check nodes and the set of FEC check nodes;

Determine the twelfth information transmitted from the ISI check node set to the information node set according to the eleventh information, and determine the thirteenth information transmitted from the FEC check node set to the information node set according to the eleventh information;

The twelfth information and the thirteenth information are summed to obtain the fifth output information for decision.

Optionally, in some possible implementation manners, there is a second correspondence between the information node set and the forward error correction FEC check node set, the ISI check node set includes M groups of ISI check nodes, and M is greater than 1. Each group of ISI check nodes includes at least one ISI check node, and the digital processing chip is specifically used for:

Determine, according to the first information, the second information transmitted by the first group of ISI check nodes in the ISI check node set to the information node set;

After summing the second information to obtain the first output information for decision, the digital processing chip is also used for:

Determine, according to the sixth information, the seventh information transmitted by the second group of ISI check nodes in the ISI check node set to the information node set;

Optionally, in some possible implementation manners, there is a second correspondence between the set of information nodes and the set of FEC check nodes, and the set of ISI check nodes includes M groups of ISI check nodes, and M is an integer greater than 1, each The group ISI check node includes at least one ISI check node. After obtaining the service signal with ISI to be processed, the digital processing chip is also used for:

Determine the twelfth information transmitted by the first group of ISI check nodes in the ISI check node set to the information node set according to the eleventh information, and determine the tenth information transmitted by the FEC check node set to the information node set according to the eleventh information Three information;

Determine the fourteenth information transmitted from the set of information nodes to the set of ISI check nodes according to the twelfth information and the thirteenth information;

Determine the fifteenth information transmitted by the second group of ISI check nodes in the ISI check node set to the information node set according to the fourteenth information, and determine the tenth information transmitted by the FEC check node set to the information node set according to the fourteenth information Six information;

The fifteenth information and the sixteenth information are summed to obtain the sixth output information for decision.

Optionally, in some possible implementation manners, the digital processing chip is specifically used for:

It is determined according to the first information that the first group of ISI check nodes in the ISI check node set transmits the second information to the first group of information nodes in the information node set that has a first correspondence with the first group of ISI check nodes. The group of ISI check nodes includes at least one ISI check node, the first group of information nodes includes at least one information node, and the second information includes the second soft information transmitted by the first group of ISI check nodes to the first group of information nodes. The soft information includes the logarithm of the ratio of the first probability to the second probability based on the service signal;

After determining the second information transmitted from the ISI check node set to the information node set according to the first information, the digital processing chip is further used for:

If the soft information corresponding to the first information node in the first group of information nodes is less than the preset threshold, it is determined that the first information node transmits the first information node to the second group of ISI check nodes that have the first corresponding relationship with the first information node. Seventeen information, the second group of ISI check nodes includes at least one ISI check node;

Determine the eighteenth information transmitted by the second group of ISI check nodes to the set of information nodes according to the seventeenth information;

If the soft information corresponding to the second information node in the first group of information nodes is greater than the preset threshold, it is determined that the second information node transmits to the third group of ISI check nodes that do not have the first corresponding relationship with the second information node. Nineteenth information, the third group of ISI check nodes includes at least one ISI check node;

According to the nineteenth information, determine the twentieth information transmitted by the third group of ISI check nodes to the set of information nodes.

It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

In the embodiment of the present application, the receiver obtains the service signal with ISI to be processed, and then determines the first information transmitted from the set of information nodes to the set of ISI check nodes, where there is between the set of information nodes and the set of ISI check nodes The first correspondence, the first correspondence includes the correspondence between each ISI check node and the N information nodes in the information node set, and the correspondence between each information node and at least one ISI check node, where N is greater than or An integer equal to 1, and N is positively correlated with the memory length of ISI. Then, according to the first information, determine the second information transmitted by the ISI check node set to the information node set, and then sum the second information to obtain the first information used for decision. Output information. In the above manner, sequence detection is performed by exchanging information between the set of information nodes and the set of ISI check nodes, thereby eliminating the influence of ISI, and each ISI check node corresponds to N information nodes, that is, the ISI check node There is a linear correspondence between the set and the set of information nodes. Then as the memory length of ISI grows, the complexity of information transmission between the set of ISI check nodes and the set of information nodes will only increase linearly, reducing the sequence detection the complexity.

Description of the drawings

Figure 1 is a schematic diagram of a transmitter;

Fig. 2 is a schematic structural diagram of a coherent receiver in this application;

FIG. 3 is a schematic diagram of an embodiment of the signal processing method in this application;

Figure 4a is a schematic diagram of establishing an ISI verification relationship in this application;

Figure 4b is a schematic structural diagram of the ISI verification relationship in this application;

Figure 4c is another schematic diagram of establishing an ISI verification relationship in this application;

Figure 4d is a schematic diagram of another structure of the ISI verification relationship in this application;

FIG. 5 is a schematic diagram of an embodiment of serial iteration between ISI verification and FEC verification in this application;

FIG. 6 is a schematic structural diagram of serial iteration between ISI verification and FEC verification in this application;

FIG. 7 is a schematic diagram of an embodiment of parallel iteration between ISI verification and FEC verification in this application;

FIG. 8 is a schematic diagram of a structure of parallel iteration between ISI verification and FEC verification in this application;

Figure 9 is a schematic structural diagram of a possible receiver.

detailed description

The embodiments of the present application provide a signal processing method, a receiver, and a digital processing chip, which reduce the complexity of sequence detection. It should be noted that the terms "first", "second", "third" and "fourth" in the description and claims of this application and the above-mentioned drawings are used to distinguish similar objects, rather than limiting specific The order or precedence. It should be understood that the above terms can be interchanged under appropriate circumstances, so that the embodiments described in this application can be implemented in a sequence other than the content described in this application. In addition, the terms "include" and "have" and any variations of them are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those clearly listed, but may include those that are not clearly listed or are related to these processes, methods, products, or Other steps or units inherent to the equipment.

Referring to the structural diagram of the transmitter 10 shown in FIG. 1, the information bit sequence output by the FEC module 101 is processed by the interleaver 102 to obtain an interleaved information bit sequence, and then the constellation data is obtained after processing by the constellation mapping module 103, and then The output signal is obtained after processing by the waveform shaping and damage compensation module 104, the digital-to-analog conversion module 105, and the modulator 106 in turn. The output signal is amplified and transmitted to the receiver through a channel, where the channel can be a physical medium for information transmission. For example, antennas, network cables, vacuum, and optical fibers, etc., are not specifically limited here.

Referring to FIG. 2, the present application can be applied to the polarization multiplexed coherent receiver 20. Specifically, the coherent receiver front end 202 receives the impaired service signal from the channel and mixes the signal with the signal from the local laser 201 Then the coherent receiver front end 202 converts the mixed optical signal into an electrical signal, and then outputs the electrical signal to the analog-to-digital conversion module 203, which converts the electrical signal into a digital signal, and outputs it to the dispersion compensator 204. The chromatic dispersion compensator 204 compensates for the chromatic dispersion generated during signal transmission, the equalizer 205 is used for depolarization multiplexing and channel damage compensation, and the phase recovery module 206 is used for phase recovery of the signal output by the equalizer 205, and Output the phase-recovered signal to the post filter 207, which is used to whiten the phase-recovered signal and introduce intersymbol interference (ISI), and then output the service signal with ISI to The information iteration module 208 and the information iteration module 208 may perform sequence detection and forward error correction (FEC) verification on the signal with ISI to restore the original signal. For example, the information iteration module 208 may include a sequence detector and FEC module, the output signal of the post filter 207 is input to the sequence detector. The sequence detector is used to eliminate the influence of ISI and output soft information to the FEC module. After the FEC module is processed, it outputs the soft information to the sequence detector to complete the sequence detector Iteration of soft information with FEC module can improve system performance.

It should be noted that the coherent receiver in this application may be any communication system receiver that uses an iterative manner to perform sequence detection and FEC verification, and the specifics are not limited here.

One of the current implementation schemes for sequence detection is to use the BCJR algorithm to eliminate the impact of ISI. Taking the ISI memory length as m and the number of modulated bits per symbol as b as an example, the corresponding state number is 2 ^{b(m -1)} It can be seen that the complexity of sequence detection has an exponential relationship with the memory length m of ISI, resulting in higher complexity of sequence detection.

For this reason, this application provides a signal processing method, which can reduce the complexity of sequence detection, which is described in detail below:

FIG. 3 is a schematic diagram of an embodiment of the signal processing method of this application. In this example, the signal processing method includes the following steps.

301. Obtain a service signal with ISI to be processed.

The transmission of the original signal transmitted by the transmitter through the channel will be subject to channel interference, so the receiver will receive the signal with impairment from the channel, and the signal will pass through the post filter 207 to narrow the frequency, because the signal can include multiple A sequence, then adjacent sequences will interfere with each other, resulting in ISI. Specifically, the signal processing method of this embodiment is mainly applied to the information iteration module 208, then the service signal with ISI to be processed may be the output signal of the post filter 207.

The following describes the relationship between the output signal of the post filter 207 and the original signal transmitted by the transmitter. For example,

Wherein, y _k represents the output signal of the post filter 207; x _'k denotes the output signal of the phase recovery module 206, i.e., the input signal of the post filter 207, is an estimate of the original signal x _k; x _k is emitted The bit stream data encoded by the machine FEC passes through the interleaver, and the original signal is mapped, x′ _k = x _k + estimation error; h _Li is the filter coefficient of the post filter 207, where L represents the memory length of the ISI, and That is the length of the filter coefficient.

302. Determine the first information transmitted by the set of information nodes to the set of ISI check nodes.

In this embodiment, the set of information nodes and the set of ISI check nodes are functional units for calculating the probability that the original signal corresponding to the service signal is equal to 0 or 1. The first information includes at least the information node corresponding to it. The first soft information transmitted by an ISI check node, specifically, the first soft information may be the logarithm of the ratio of the first probability to the second probability, where the first probability is the original signal corresponding to the service signal equal to 0 Probability, the second probability is the probability that the original signal corresponding to the service signal is equal to 1. It is understandable that if it is in the initialization phase, that is, there is no service signal input with ISI, the first soft information is 0, that is, the first information transmitted by the set of information nodes to the set of ISI check nodes is 0. If there is already a service signal input with ISI, the first information can be determined by the information transmitted from the set of ISI check nodes to the set of information nodes, which will be further described later.

It should be noted that there is a first correspondence between the set of information nodes and the set of ISI check nodes. Specifically, the first correspondence includes the correspondence between each ISI check node and N information nodes and each information node For the corresponding relationship with at least one ISI check node, N is an integer greater than or equal to 1, and N is positively correlated with the memory length of the ISI.

The following describes the first correspondence relationship with a specific example:

Referring to Figure 4a, the first correspondence is described by taking ISI memory length L=3, PAM2 (1bit information maps one constellation point) as an example, where u1, u2...u10 correspond to the bit data of the original signal output by the FEC module 101 , These bit data meet the FEC check relationship, u1, u2...u10 are processed by the interleaver 102 to obtain the same size bit sequence b1, b2...b10, the two correspond one to one, and then b1, b2...b10 are mapped according to certain rules As constellation points, constellation data x1, x2...x10 are generated. Further referring to Figure 4b, hiding b1, b2...b10 and x1, x2...x10 can obtain the corresponding relationship between u1, u2...u10 and y1, y2...y10 as shown in Figure 4b. Specifically, u1, u2...u10 can be regarded as a collection of information nodes corresponding to the original signal, and y1, y2...y10 can be regarded as a collection of ISI check nodes that take service signals with ISI as input. It can be seen that due to ISI The memory length of is 3, and 1bit information maps a constellation point, so each ISI check node has a corresponding relationship with 3 information nodes.

In addition, based on different modulation methods, the ISI check relationship can also have other forms. Please refer to Figure 4c. Take the ISI memory length L=3, PAM4 (2bit information mapping one constellation point) as an example to describe the first correspondence relationship , It can be seen that since the memory length of ISI is 3, each y corresponds to 3 x, and since 2bit information maps a constellation point, each x corresponds to 2 b. Furthermore, please refer to Figure 4d, hiding b1, b2...b10 and x1, x2...x10 can get the corresponding relationship between u1, u2...u10 and y1, y2...y10 as shown in Figure 4d. It can be seen that each ISI The check node has a corresponding relationship with 6 information nodes.

Through the foregoing description, the first correspondence is a linear correspondence, and the number of information nodes corresponding to each ISI check node is the product of the memory length of the ISI and the number of bits corresponding to each constellation point. Corresponding to different ISI memory lengths or different modulation modes, the first corresponding relationship may be different, and the specific relationship is not limited here.

303. Determine, according to the first information, the second information transmitted by the ISI check node set to the information node set.

In this embodiment, the second information transmitted by the ISI check node set to the information node can be determined based on the first information, where the second information includes the information transmitted by each ISI check node to the corresponding N information nodes. The second soft information, specifically, the second soft information is different from the foregoing first soft information, and is based on the logarithm of the ratio of the first probability to the second probability under the condition that a service signal with ISI is used as an input.

The following takes an ISI check node as an example to describe the calculation method of the second soft information:

The second soft information can be calculated according to the following Bayesian formula. Specifically, the Bayesian formula can be:

among them,

Is the second soft information, B _j represents an ISI check node, A _i represents one of the information nodes that has a first corresponding relationship with B _j , and P(A _i =0|B _j ) represents the input corresponding to B _j If it is a service signal with ISI, the probability that the original signal corresponding to A _i takes a value of 0, P(A _i =1|B _j ) means that under the condition that the input corresponding to B _j is a service signal with ISI, The probability that the original signal corresponding to A _i is 1,

Represents the soft information transmitted from A _i to B _j before.

Taking Figure 4b as an example, if B _j is y5, then the information nodes that have a first correspondence with B _j can be u1, u5, and u9 connected to y5. Then in step 302, u1, u5, and u9 can be directed to y5 soft information transmission, is if a _i u1, u1 is transmitted to the information y5 need to calculate the information based on the transmission y5 step U9 and u5, u1 does not include the step of transmitting information to y5, i.e.

In the same way, the information transmitted from y5 to u5 needs to be calculated based on the information transmitted from u1 and u9 to y5 in the previous step, and the information transmitted from y5 to u9 needs to be calculated based on the information transmitted from u1 and u5 to y5 in the previous step. In other words, the information transmitted by an ISI check node to an information node depends on the information transmitted to the ISI check node by all other information nodes connected to the ISI check node except the information node itself in the previous step. .

On this basis, the above formula can be further refined as:

among them,

B _j represents the transmission of information to the A _i,

Represents all the information nodes connected to B _j ,

It means that _Ak is the remaining information node except A _i among all the information nodes connected to B _j ,

Represents the information transmitted from _Ak to B _j in the previous step,

Can be determined by the above

determine.

It should be noted that after determining the second information transmitted by the ISI check node set to the information node set according to the first information, the third information transmitted by the information node set to the ISI check node set may be further determined according to the second information. , That is, the information node set can determine the information transmitted to the ISI check node set based on the information from the ISI check node set. It can be understood that the third information is similar to the first information, and also includes the direction and The corresponding ISI checks the soft information transmitted by the node.

Taking a certain information node as an example, the calculation method of the soft information in the third information is described below:

The soft information in the third information can be calculated according to the following formula, which can be:

among them,

Represents the soft information transmitted from A _i to B _h , A _i represents a certain information node, and B _h represents one of the ISI check nodes that has a first corresponding relationship with A _i ,

Indicates all ISI check nodes connected to A _i ,

Indicates that B _k is the remaining ISI check node except B _h among all ISI check nodes connected to A _i ,

On the information showing the step A _i B _k transmitted. That is to say, the soft information transmitted from A _i to B _h is obtained by summing the information transmitted from B _k to A _i . According to the above method, the soft information transmitted by each information node to its corresponding ISI check node can be calculated. Information, the collection of these soft information is the third information.

Taking Figure 4b as an example, if the first information node is u1, then the second ISI check node can be y5, y6 and y7 connected to u1, then the information transmitted from u1 to y5 needs to be transmitted to u1 according to the previous step y6 and y7 The information transmitted from u1 to y6 needs to be calculated based on the information transmitted from y5 and y7 to u1 in the previous step, and the information transmitted from u1 to y7 needs to be calculated based on the information transmitted from y5 and y6 to u1 in the previous step.

Next, repeat the information interaction between the set of information nodes and the set of ISI check nodes to achieve sequence detection by means of information iteration. For example, determine the fourth transmission from the set of ISI check nodes to the set of information nodes based on the third information. Information, etc., will not be detailed here. In addition, this application does not limit the number of iterations of information iteration.

304. Sum the second information to obtain first output information used for decision.

In this embodiment, after the ISI check node set transmits the second information to the information node set, the second information can be summed to obtain the first output information used for decision. It is understandable that if there is a next round In the iterative interaction, the output information used for decision can also be determined after the next round of iteration ends. For example, the second output information used for decision can be obtained by summing the fourth information.

It should be noted that in addition to performing sequence detection according to the embodiment shown in FIG. 3, the receiver can also perform FEC verification, and the system performance can be improved by combining sequence detection and FEC verification. Among them, there are many ways to combine sequence detection and FEC verification, for example, it can be a serial iteration between sequence detection and FEC verification, that is, sequence detection independent iteration, and unified output soft information for FEC verification iteration use , And then FEC verification independent iteration, and unified output of soft information for sequence detection iterative use, so as to perform serial iteration; in addition, it can also be a parallel iteration between sequence detection and FEC verification, that is, sequence detection and FEC verification Can be synchronized. The following is a detailed description of the multiple possible iterative processes described above:

The first is to perform serial iteration between ISI verification and FEC verification.

Please refer to Fig. 5. In this example, the serial iteration between sequence detection and FEC verification includes the following steps.

501. The collection of information nodes is updated.

In this embodiment, the information node update refers to determining the information transmitted from the set of information nodes to the set of ISI check nodes. In the first update process of the information node after initialization, the set of information nodes transmits to the set of ISI check nodes. The information is 0, and in the subsequent process of updating the information node, the information node set can determine the information transmitted to the ISI check node set based on the information from the ISI check node set.

502. The ISI check node set is updated.

In this embodiment, ISI check node update refers to determining the information transmitted from the set of ISI check nodes to the set of information nodes. Specifically, the method for updating the ISI check node is similar to step 303 in the embodiment shown in FIG. 3. I won't repeat them here.

503. Output soft information for FEC verification.

In this embodiment, the first output information that needs to be output can be determined after the ISI check node is updated. The first output information can be provided for FEC verification. Specifically, the calculation method and diagram of the first output information Step 304 in the embodiment shown in 3 is similar, and details are not repeated here.

It should be noted that before outputting soft information for FEC verification, sequence detection can be independently iterated, that is, steps 501-502 are repeated, and the soft information for FEC verification is output after the iteration of sequence detection ends, for example, the The soft information used for FEC verification may also be the aforementioned second output information.

504. FEC verification.

In this embodiment, the receiver may further perform FEC verification according to the soft information output after sequence detection. Specifically, there is a second correspondence between the set of information nodes and the set of FEC verification nodes, and the FEC verification process may include The FEC check node is updated, that is, the fifth information transmitted by the FEC check node set to the information node set is determined according to the first output information output after the sequence detection, or the FEC calibration can be determined according to the second output information output after the sequence detection The eighth information transmitted by the verification node set to the information node set.

It should be noted that the FEC verification process can also be independently iterated, that is, information iteration is carried out between the FEC verification node set and the information node set. The iterative process of the FEC verification is similar to the commonly used methods in actual applications. There are no restrictions.

505. Output soft information for sequence detection.

In this embodiment, after the FEC verification is completed, soft information is also output for use in sequence detection. Therefore, the next round of sequence detection in step 501 needs to be performed based on the soft information output after the FEC verification. Specifically, the information transmitted by the information node to the ISI check node can be calculated according to the following formula, which can be:

among them,

Represents the soft information output after FEC verification. The difference from the formula used to calculate the soft information of the third information in step 303 of the embodiment shown in FIG. 3 is that the formula in this embodiment adds

Sum is performed, that is, sequence detection is no longer an independent iterative process but an iterative process combined with FEC verification.

For example, the process of performing steps 501-502 after step 505 may be to determine the sixth information transmitted by the information node set to the ISI check node set according to the second information and the fifth information, and then determine the ISI check according to the sixth information The seventh information transmitted by the set of nodes to the set of information nodes; or, it may be the ninth information transmitted from the set of information nodes to the set of ISI check nodes based on the fourth information and the eighth information, and then determine the ISI check based on the ninth information The tenth information transmitted by the node set to the information node set.

506. Output soft information for judgment.

In this embodiment, after the serial iteration between sequence detection and FEC verification ends, output information for decision can be output. Specifically, the final output information used for decision can be obtained by summing the soft information output in step 503 and the soft information output in step 505. For example, the fifth information and the seventh information may be summed to obtain the third output information for decision, or the eighth information and the tenth information may be summed to obtain the fourth output information for decision.

The following uses an example to further introduce the structure of the serial iteration between sequence detection and FEC verification. Please refer to Figure 6, y1-y10 are ISI check nodes, b1-b10 are information nodes, and u1-u10 are passed After interleaving, the equivalent nodes corresponding to b1-b10, p1-p10 are FEC check nodes. Sequence detection is performed between y1-y10 and b1-b10, and the soft information output after sequence detection is processed by the de-interleaver and provided to u1-u10, and then between u1-u10 and p1-p10 is the soft information output after sequence detection Perform FEC verification, the soft information output after FEC verification is processed by the interleaver and provided to b1-b10, and then between y1-y10 and b1-b10, the soft information output after FEC verification continues in the next round of iteration Perform sequence detection, and so on, the serial iteration between sequence detection and FEC verification.

The second is parallel iteration between sequence detection and FEC verification.

Please refer to FIG. 7. In this example, parallel iteration between ISI verification and FEC verification includes the following steps.

701. The collection of information nodes is updated.

In this embodiment, the update of the information node set includes determining the information transmitted by the information node set to the ISI check node set and the information transmitted by the information node set to the FEC check node set. Specifically, the eleventh information transmitted by the set of information nodes to the set of ISI check nodes and the set of FEC check nodes can be determined. It is understandable that the eleventh information is 0 in the first iteration after initialization, and the eleventh information can be transmitted from the ISI check node set and the FEC check node set to the information node set in the subsequent iterations The information is confirmed and will be further explained later.

702. Update the set of ISI check nodes and update the set of FEC check nodes.

In this embodiment, since sequence detection and FEC verification are parallel iterations, both the ISI check node set update and the FEC check node set update are required. Specifically, the ISI check can be determined according to the eleventh information. Verify the twelfth information transmitted by the node set to the information node set, and determine the thirteenth information transmitted by the FEC check node set to the information node set according to the eleventh information. Among them, the description about the update of the ISI check node set is similar to step 303 in the embodiment shown in FIG. 3, and the description about the update of the FEC check node set is similar to step 504 in the embodiment shown in FIG. 5, and the details are not repeated here. .

After step 702 is over, step 701 is repeated to iterate. For a certain information node, there may be both an ISI check node and an FEC check node connected to the information node. Then it is necessary to determine the direction of the ISI check node The information transmitted by the information node must also determine the information transmitted by the FEC check node to the information node.

Specifically, the information transmitted by a certain information node to the corresponding ISI check node and FEC check node can be calculated according to the following formula, which can be:

The difference from the formula used to calculate the soft information of the third information in step 303 of the embodiment shown in FIG. 3 is:

A _i represents the soft information transmission B _h, A _i represents an information node, B _h A _i represents the ISI having a check node wherein the first correspondence relationship or A _i having a second correspondence relationship wherein one FEC Check node,

Indicates all check nodes connected to A _i (including ISI check nodes and FEC check nodes),

It means that B _k is all check nodes connected to A _i (including ISI check nodes and FEC check nodes) except for the remaining check nodes (including ISI check nodes and FEC check nodes) except B _h ,

On the information showing the step A _i B _k transmitted.

The following uses an example to further introduce the structure of parallel iteration between sequence detection and FEC verification. Please refer to Figure 8. b1-10 are information nodes, y1-y4 are ISI verification nodes, and p1-p4 are FEC verification nodes. Test node. Taking b4 as an example, the ISI check nodes connected to b4 are y1 and y2, and the FEC check node connected to b4 is p4. Then the information transmitted from b4 to y1 needs to be calculated based on the information transmitted from y2 and p4 to b4, b4 The information transmitted to y2 needs to be calculated based on the information transmitted from y1 and p4 to b4, and the information transmitted from b4 to p4 needs to be calculated based on the information transmitted from y1 and y2 to b4.

It should be noted that, similar to the embodiment shown in FIG. 5, in order to reduce the complexity of an iteration and accelerate the convergence speed, each ISI check node update can only be updated for the partial check ISI check node, and each FEC The check node update can be performed on part or all of the FEC check nodes. The method of selecting the ISI check node for each iteration will not be repeated here.

703. Output soft information for judgment.

In this embodiment, after the parallel iteration between the ISI check and the FEC check ends, the soft information after the update of the ISI check node set and the updated soft information of the FEC check node set can be summed to output the soft information. For judgment, specifically, the fifth output information for judgment can be obtained by summing the above-mentioned twelfth information and thirteenth information.

From the perspective of the flow of information flow transmission, the embodiment shown in Figure 5 above requires soft information to be transmitted between sequence detection and FEC verification, and in this embodiment, the transmission of information flow no longer distinguishes between sequence detection and FEC verification. The sequence detection can be performed synchronously with the FEC check to complete one iteration. Compared with the serial iterative method, this parallel iteration method reduces the transmission of information and improves the efficiency of sequence detection and FEC verification.

The two iterative processes between sequence detection and FEC verification are described above. It should be noted that in order to further reduce the complexity of sequence detection and speed up convergence, each ISI verification node update can only be used for partial calibration. The ISI check node is updated. Specifically, the set of ISI check nodes may include M groups of ISI check nodes, where M is an integer greater than 1, and each group of ISI check nodes includes at least one ISI check node. In the process of determining the second information transmitted from the set of ISI check nodes to the set of information nodes by one information, the M sets of sub-information transmitted by the M sets of ISI check nodes to the corresponding information nodes can be sequentially determined according to the first information, and then The second information is determined according to the M groups of sub-information. Taking Figure 4b as an example, there are a total of 10 ISI check nodes y1-y10, and one or more ISI check nodes can be selected from y1-y10 to update each time, and the ISI check nodes selected each time can be the same or Can be different.

In practical applications, the ISI check nodes participating in the sequence detection can be determined each time according to fixed rules. For example, if the number of ISI check nodes in each group is the same, then the y1 and y2 of the first group can be updated sequentially. Update y3 and y4 of the second group, update y5 and y6 of the third group, update y7 and y8 of the fourth group, update y9 and y10 of the fifth group, and check the ISI of each group After the node is completed, it can be determined that the update of the ISI check node set is completed.

In addition, the ISI check nodes that participate in sequence detection each time are also screened according to certain conditions. For example, the ISI check nodes that need to participate in the current iteration can be determined according to the updated soft information of the ISI check node in the previous iteration. Yes, a threshold can be set. If the soft information corresponding to an information node in the previous iteration is less than the threshold, all or part of the ISI check nodes connected to the information node in the current iteration are selected. Otherwise, the ISI check node connected to the information node is not selected in the current iteration. Taking Figure 4b as an example, if the ISI check node y5 is updated in the last iteration, the soft information transmitted by y5 to u1, u5, and u9 respectively is determined. Among them, the soft information corresponding to u9 is less than the threshold, and The soft information corresponding to u1 and u5 is greater than the threshold, then the ISI check node participating in the current iteration will be selected from y3, y4, and y5 corresponding to u9.

It is understandable that the methods for selecting ISI check nodes in each iteration include but are not limited to the methods listed above.

As for the update of information nodes, because the calculation method is simple summation calculation, each information node update can be to update all information nodes.

The signal processing method in the embodiment of the present application is described above, and the receiver in the embodiment of the present application is described below:

Figure 9 is a schematic structural diagram of a possible receiver. The receiver includes a receiver front end 901 and a digital processing chip 902, and the receiver front end 901 and the digital processing chip 902 are interconnected by wires. Among them, the receiver front end 901 is used to convert the received optical signal into an electrical signal, and transmit the electrical signal to the digital processing chip 902. The digital processing chip 902 is used to execute the method steps of the embodiments shown in FIG. 3, FIG. 5, and FIG. In a possible implementation manner, the digital processing chip 902 may include a dispersion compensator 204, an equalizer 205, a phase recovery module 206, a post filter 207, and an information iteration module 208 as shown in FIG. 2. Specifically, digital The electrical signal received by the processing chip 902 can be processed by the dispersion compensator 204, the equalizer 205, the phase recovery module 206, and the post filter 207 successively, and the post filter 207 outputs the service signal with ISI, and then the information The iteration module 208 performs further processing on the service signal with ISI, that is, the information iteration module 208 is used to execute the method steps of the embodiments shown in FIG. 3, FIG. 5, and FIG. 7.

The embodiment of the application also provides a digital processing chip. The digital processing chip integrates a processor and one or more interfaces for implementing the method steps of the embodiments shown in FIG. 3, FIG. 5, and FIG. 7. When a memory is integrated in the digital processing chip, the digital processing chip can complete the method steps of any one or more of the foregoing embodiments. When the memory is not integrated in the digital processing chip, it can be connected to an external memory through an interface. The digital processing chip implements the actions performed by the receiver in the foregoing embodiment according to the program code stored in the external memory.

Those of ordinary skill in the art can understand that all or part of the steps in the foregoing embodiments can be implemented by hardware, or by a program instructing relevant hardware to be completed. The program can be stored in a computer-readable storage medium. The storage medium mentioned can be read-only memory, random access memory, etc. Specifically, for example: the above-mentioned processing unit or processor may be a central processing unit, a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device , Transistor logic devices, hardware components, or any combination thereof. Whether the above-mentioned functions are executed by hardware or software depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of this application.

When implemented by software, the method steps described in the above embodiments may be implemented in the form of computer program products in whole or in part. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center. Transmission to another website site, computer, server or data center via wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or a data center integrated with one or more available media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk (SSD)).

Finally, it should be noted that the above are only specific implementations of this application, but the scope of protection of this application is not limited to this. Anyone skilled in the art can easily fall within the technical scope disclosed in this application. Any change or replacement should be covered in the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

A signal processing method, characterized by comprising:

Obtain the to-be-processed service signal with inter-code crosstalk ISI;

Determine the first information transmitted from the set of information nodes to the set of ISI check nodes, where there is a first correspondence between the set of information nodes and the set of ISI check nodes, and the first correspondence includes the ISI check node The correspondence between each ISI check node in the set and the N information nodes in the information node set and the correspondence between each information node in the information node set and at least one ISI check node, where N is greater than Or an integer equal to 1, and the N is positively correlated with the memory length of the ISI, the first information includes the at least one information node that has the corresponding relationship with each information node The first soft information transmitted by the ISI check node, where the first soft information includes the logarithm of the ratio of the first probability to the second probability, and the first probability is the probability that the original signal corresponding to the service signal is equal to 0, The second probability is the probability that the original signal is equal to 1;

Determine, according to the first information, second information transmitted from the set of ISI check nodes to the set of information nodes, where the second information includes the communication between each ISI check node and each ISI check node Second soft information transmitted by the N information nodes having the first corresponding relationship, where the second soft information includes a logarithm of the ratio of the first probability to the second probability based on the service signal;

The first output information used for decision is obtained by summing the second information.
The method according to claim 1, wherein the set of ISI check nodes includes M groups of ISI check nodes, where M is an integer greater than 1, and each group of ISI check nodes includes at least one ISI check node The determining, according to the first information, the second information transmitted from the set of ISI check nodes to the set of information nodes includes:

Sequentially determine, according to the first information, the M groups of sub-information that the M groups of ISI check nodes transmit to the information nodes corresponding to the M groups of ISI check nodes;

The second information is determined according to the M groups of sub-information.
The method according to claim 1 or 2, wherein after determining the second information transmitted from the set of ISI check nodes to the set of information nodes according to the first information, the method further comprises:

Determining, according to the second information, the third information transmitted by the set of information nodes to the set of ISI check nodes;

Determining, according to the third information, fourth information transmitted by the set of ISI check nodes to the set of information nodes;

The second output information used for decision is obtained by summing the fourth information.
The method according to claim 1 or 2, wherein there is a second correspondence between the set of information nodes and the set of forward error correction FEC check nodes, and the sum of the second information is used for decision After the first output information, the method further includes:

Determining, according to the first output information, fifth information transmitted by the FEC check node set to the information node set;

Determining, according to the second information and the fifth information, the sixth information transmitted by the set of information nodes to the set of ISI check nodes;

Determining, according to the sixth information, seventh information transmitted by the set of ISI check nodes to the set of information nodes;

The fifth information and the seventh information are summed to obtain third output information for decision.
The method according to claim 3, characterized in that there is a second correspondence between the set of information nodes and the set of FEC check nodes, and after summing the fourth information to obtain the second output information for decision , The method further includes:

Determining, according to the second output information, the eighth information transmitted by the FEC check node set to the information node set;

Determining, according to the fourth information and the eighth information, the ninth information transmitted by the set of information nodes to the set of ISI check nodes;

Determining, according to the ninth information, the tenth information transmitted from the set of ISI check nodes to the set of information nodes;

Sum the eighth information and the tenth information to obtain fourth output information used for decision.
The method according to claim 1 or 2, characterized in that there is a second correspondence between the set of information nodes and the set of FEC check nodes, and after obtaining the service signal with ISI to be processed, the method further comprises :

Determining the eleventh information transmitted by the set of information nodes to the set of ISI check nodes and the set of FEC check nodes;

Determine the twelfth information transmitted from the set of ISI check nodes to the set of information nodes according to the eleventh information, and determine the set of FEC check nodes to the set of information nodes according to the eleventh information The thirteenth information transmitted;

Sum the twelfth information and the thirteenth information to obtain fifth output information for decision.
The method according to claim 1, wherein there is a second correspondence between the set of information nodes and the set of forward error correction FEC check nodes, and the set of ISI check nodes includes M groups of ISI check nodes , The M is an integer greater than 1, each group of ISI check nodes includes at least one ISI check node, and it is determined according to the first information that the second information transmitted by the ISI check node set to the information node set includes :

Determine, according to the first information, the second information transmitted by the first group of ISI check nodes in the ISI check node set to the information node set;

After summing the second information to obtain the first output information for decision, the method further includes:

Determining, according to the first output information, fifth information transmitted by the FEC check node set to the information node set;

Determining, according to the second information and the fifth information, the sixth information transmitted by the set of information nodes to the set of ISI check nodes;

Determining, according to the sixth information, the seventh information transmitted by the second group of ISI check nodes in the ISI check node set to the information node set;

The fifth information and the seventh information are summed to obtain third output information for decision.
The method according to claim 1, wherein there is a second correspondence between the set of information nodes and the set of FEC check nodes, and the set of ISI check nodes includes M groups of ISI check nodes, and the M Is an integer greater than 1, each group of ISI check nodes includes at least one ISI check node, and after obtaining the service signal with ISI to be processed, the method further includes:

Determining the eleventh information transmitted by the set of information nodes to the set of ISI check nodes and the set of FEC check nodes;

Determine the twelfth information transmitted by the first group of ISI check nodes in the ISI check node set to the information node set according to the eleventh information, and determine the FEC check according to the eleventh information The thirteenth information transmitted by the node set to the information node set;

Determining, according to the twelfth information and the thirteenth information, the fourteenth information transmitted by the set of information nodes to the set of ISI check nodes;

Determine the fifteenth information transmitted by the second group of ISI check nodes in the ISI check node set to the information node set according to the fourteenth information, and determine the FEC check according to the fourteenth information The sixteenth information transmitted by the node set to the information node set;

The fifteenth information and the sixteenth information are summed to obtain sixth output information for decision.
The method according to claim 1, wherein determining, according to the first information, the second information transmitted from the set of ISI check nodes to the set of information nodes comprises:

Determine, according to the first information, the first group of ISI check nodes in the ISI check node set to the first group in the information node set that has the first correspondence with the first group of ISI check nodes The second information transmitted by an information node, the first group of ISI check nodes includes at least one ISI check node, the first group of information nodes includes at least one information node, and the second information includes the first group of ISI Second soft information transmitted by the check node to the first group of information nodes, where the second soft information includes the logarithm of the ratio of the first probability and the second probability based on the service signal;

After determining the second information transmitted from the set of ISI check nodes to the set of information nodes according to the first information, the method further includes:

If the soft information corresponding to the first information node in the first group of information nodes is less than the preset threshold value, it is determined that the first information node is assigned to the second information node that has the first corresponding relationship with the first information node. Seventeenth information transmitted by a group of ISI check nodes, where the second group of ISI check nodes includes at least one ISI check node;

Determining, according to the seventeenth information, the eighteenth information transmitted by the second group of ISI check nodes to the information node set;

If the soft information corresponding to the second information node in the first group of information nodes is greater than the preset threshold, it is determined that the second information node is directed to the first information node that does not have the first corresponding relationship with the second information node. Nineteenth information transmitted by three groups of ISI check nodes, where the third group of ISI check nodes includes at least one ISI check node;

Determine, according to the nineteenth information, the twentieth information transmitted by the third group of ISI check nodes to the information node set.
A digital processing chip, characterized in that the chip includes a processor and a memory, the memory and the processor are interconnected by wires, the memory is stored with instructions, and the processor is used to execute The signal processing method of any one of 9.
A receiver, characterized by comprising:

A receiver front end and a digital processing chip, where the receiver front end and the digital processing chip are interconnected by wires;

The receiver front end is used to convert the received optical signal into an electrical signal, and transmit the electrical signal to the digital processing chip;

The digital processing chip is used to perform the following steps:

Obtain the to-be-processed service signal with inter-code crosstalk ISI;

Determine the first information transmitted from the set of information nodes to the set of ISI check nodes, where there is a first correspondence between the set of information nodes and the set of ISI check nodes, and the first correspondence includes the ISI check node The correspondence between each ISI check node in the set and the N information nodes in the information node set and the correspondence between each information node in the information node set and at least one ISI check node, where N is greater than Or an integer equal to 1, and the N is positively correlated with the memory length of the ISI, the first information includes the at least one information node that has the corresponding relationship with each information node The first soft information transmitted by the ISI check node, where the first soft information includes the logarithm of the ratio of the first probability to the second probability, and the first probability is the probability that the original signal corresponding to the service signal is equal to 0, The second probability is the probability that the original signal is equal to 1;

Determine, according to the first information, second information transmitted from the set of ISI check nodes to the set of information nodes, where the second information includes the communication between each ISI check node and each ISI check node Second soft information transmitted by the N information nodes having the corresponding relationship, where the second soft information includes a logarithm of a ratio of the first probability to the second probability based on the service signal;

The first output information used for decision is obtained by summing the second information.
The receiver according to claim 11, wherein the set of ISI check nodes includes M groups of ISI check nodes, where M is an integer greater than 1, and each group of ISI check nodes includes at least one ISI check node. node;

The digital processing chip is specifically used for:

Sequentially determine, according to the first information, the M groups of sub-information that the M groups of ISI check nodes transmit to the information nodes corresponding to the M groups of ISI check nodes;

The second information is determined according to the M groups of sub-information.
The receiver according to claim 11 or 12, wherein after determining the second information transmitted from the set of ISI check nodes to the set of information nodes according to the first information, the digital processing chip also uses in:

Determining, according to the second information, the third information transmitted by the set of information nodes to the set of ISI check nodes;

Determining, according to the third information, fourth information transmitted by the set of ISI check nodes to the set of information nodes;

The second output information used for decision is obtained by summing the fourth information.
The receiver according to claim 11 or 12, characterized in that there is a second correspondence between the set of information nodes and the set of forward error correction FEC check nodes, and the sum of the second information is used for After the judged first output information, the digital processing chip is also used for:

Determining, according to the first output information, fifth information transmitted by the FEC check node set to the information node set;

Determining, according to the second information and the fifth information, the sixth information transmitted by the set of information nodes to the set of ISI check nodes;

Determining, according to the sixth information, seventh information transmitted by the set of ISI check nodes to the set of information nodes;

The fifth information and the seventh information are summed to obtain third output information for decision.
The receiver according to claim 13, wherein there is a second correspondence between the set of information nodes and the set of FEC check nodes, and the second output information for decision is obtained by summing the fourth information After that, the digital processing chip is also used for:

Determining, according to the second output information, the eighth information transmitted by the FEC check node set to the information node set;

Determining, according to the fourth information and the eighth information, the ninth information transmitted by the set of information nodes to the set of ISI check nodes;

Determining, according to the ninth information, the tenth information transmitted from the set of ISI check nodes to the set of information nodes;

Sum the eighth information and the tenth information to obtain fourth output information used for decision.
The receiver according to claim 11 or 12, characterized in that there is a second correspondence between the set of information nodes and the set of FEC check nodes, and after obtaining the service signal with ISI to be processed, the digital processing The chip is also used for:

Determining the eleventh information transmitted by the set of information nodes to the set of ISI check nodes and the set of FEC check nodes;

Determine the twelfth information transmitted from the set of ISI check nodes to the set of information nodes according to the eleventh information, and determine the set of FEC check nodes to the set of information nodes according to the eleventh information The thirteenth information transmitted;

Sum the twelfth information and the thirteenth information to obtain fifth output information for decision.
The receiver according to claim 11, wherein there is a second correspondence between the set of information nodes and the set of forward error correction FEC check nodes, and the set of ISI check nodes includes M groups of ISI check nodes. Node, the M is an integer greater than 1, each group of ISI check nodes includes at least one ISI check node, and the digital processing chip is specifically used for:

Determine, according to the first information, the second information transmitted by the first group of ISI check nodes in the ISI check node set to the information node set;

After summing the second information to obtain the first output information for decision, the digital processing chip is further used for:

Determining, according to the first output information, fifth information transmitted by the FEC check node set to the information node set;

Determining, according to the second information and the fifth information, the sixth information transmitted by the set of information nodes to the set of ISI check nodes;

Determining, according to the sixth information, the seventh information transmitted by the second group of ISI check nodes in the ISI check node set to the information node set;

The fifth information and the seventh information are summed to obtain third output information for decision.
The receiver according to claim 11, wherein there is a second correspondence between the set of information nodes and the set of FEC check nodes, and the set of ISI check nodes includes M groups of ISI check nodes, and M is an integer greater than 1. Each group of ISI check nodes includes at least one ISI check node. After obtaining the service signal with ISI to be processed, the digital processing chip is further used for:

Determining the eleventh information transmitted by the set of information nodes to the set of ISI check nodes and the set of FEC check nodes;

Determine the twelfth information transmitted by the first group of ISI check nodes in the ISI check node set to the information node set according to the eleventh information, and determine the FEC check according to the eleventh information The thirteenth information transmitted by the node set to the information node set;

Determining, according to the twelfth information and the thirteenth information, the fourteenth information transmitted by the set of information nodes to the set of ISI check nodes;

Determine the fifteenth information transmitted by the second group of ISI check nodes in the ISI check node set to the information node set according to the fourteenth information, and determine the FEC check according to the fourteenth information The sixteenth information transmitted by the node set to the information node set;

The fifteenth information and the sixteenth information are summed to obtain sixth output information for decision.
The receiver according to claim 11, wherein the digital processing chip is specifically used for:

Determine, according to the first information, the first group of ISI check nodes in the ISI check node set to the first group in the information node set that has the first correspondence with the first group of ISI check nodes The second information transmitted by an information node, the first group of ISI check nodes includes at least one ISI check node, the first group of information nodes includes at least one information node, and the second information includes the first group of ISI Second soft information transmitted by the check node to the first group of information nodes, where the second soft information includes the logarithm of the ratio of the first probability and the second probability based on the service signal;

After determining the second information transmitted by the ISI check node set to the information node set according to the first information, the digital processing chip is further configured to:

If the soft information corresponding to the first information node in the first group of information nodes is less than the preset threshold value, it is determined that the first information node is assigned to the second information node that has the first corresponding relationship with the first information node. Seventeenth information transmitted by a group of ISI check nodes, where the second group of ISI check nodes includes at least one ISI check node;

Determining, according to the seventeenth information, the eighteenth information transmitted by the second group of ISI check nodes to the information node set;

If the soft information corresponding to the second information node in the first group of information nodes is greater than the preset threshold, it is determined that the second information node is directed to the first information node that does not have the first corresponding relationship with the second information node. Nineteenth information transmitted by three groups of ISI check nodes, where the third group of ISI check nodes includes at least one ISI check node;

Determine, according to the nineteenth information, the twentieth information transmitted by the third group of ISI check nodes to the information node set.