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Method for constructing LDPC code check matrix based on protograph and suitable for deep space communication

A technology of LDPC code and check matrix, which is applied to error detection coding using multi-bit parity bits, error correction/detection using block codes, data representation error detection/correction, etc., which can solve the problem that LDPC codes fail to enter. , low implementation complexity, etc.

Pending Publication Date: 2021-06-29
CHONGQING UNIV OF POSTS & TELECOMM
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Problems solved by technology

[0002] Channel coding is a technology used to improve the transmission reliability of communication systems. Low Density Parity Check Codes (LDPC codes) were proposed by Gallager in 1962 and systematically discussed the coding method and probabilistic iterative decoding of the codes. code method, gave a detailed analysis of the decoding error probability, and pointed out that in the additive white Gaussian noise (AWGN) channel, the performance of this code is close to the Shannon limit and the implementation complexity is low, but due to the current level Due to the rapid development of linked codes and the limitations of software and hardware, LDPC codes have not entered people's sight

Method used

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  • Method for constructing LDPC code check matrix based on protograph and suitable for deep space communication
  • Method for constructing LDPC code check matrix based on protograph and suitable for deep space communication
  • Method for constructing LDPC code check matrix based on protograph and suitable for deep space communication

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Embodiment 1

[0041] First perform the initialization operation to figure 1 For example, the AR4JA code rate is 1 / 2 of the original model map, and its basic matrix is:

[0042]

[0043] Each row of the basic matrix corresponds to each check node in the original model graph, and each column corresponds to each variable node in the original model graph. The position where the i-th row j column in the basic matrix is ​​not 0 represents the i-th node in the original model graph. The number of parallel edges between the jth check node and the jth variable node, and the fifth column is the punching position.

[0044] The first step is to determine the first expansion multiple L of the original model graph 1 , the second expansion multiple L 2 . In order to correspond to the LDPC code of deep space communication, the first step is expanded by the multiple L 1 Set to 4, the second expansion multiple is set to L 2 =128, ACE threshold value η=4, searched loop length 2d=6. After expansion, th...

Embodiment 2

[0060] Algorithm of the present invention is used for existing AR4JA sign indicating number, code rate 1 / 2, 2 / 3, 4 / 5 protograph, wherein the AR4JA series protograph of code rate 2 / 3, 4 / 5 is respectively as Figure 5 , Image 6 shown. Extend the first step by a factor of L 1 Both are set to 4, the second expansion multiple L 2 Set to 128, 64, 32 respectively. Construct three groups of codes with information bit length of 1024 bits, the parameters are (2048,1024), (1536,1024), (1280,1024), and the deep space communication LDPC code given by CCSDS131.0-B-3 is in Comparative analysis is carried out under the same code length and code rate. When the code rates constructed in this paper are 1 / 2, 2 / 3, and 4 / 5, their girths are 8, 8, and 6, respectively. In the CCSDS131.0-B-3 standard, the same code length The girth lengths of the code rate LDPC codes are 6, 4, and 4 respectively, and the invention improves the girth lengths of the constructed codes. In order to verify that the ...

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Abstract

The invention belongs to the technical field of channel coding, and particularly relates to a design method for constructing an LDPC code suitable for deep space communication from a protograph. According to the construction method, a two-step expansion method is adopted for expansion, a first expansion multiple is L1, and a second expansion multiple is L2. In the first expansion process, shift matrixes are searched for the positions where connection is established, the size of each shift matrix is L2 * L2, and the shift matrixes are obtained by circularly shifting right an identity matrix by w (w < L2) bits. According to the method, for three conditions existing in a PEG algorithm when edges are added, cyclic shift values of the added edges are respectively discussed and searched, short rings are eliminated, the edges with high connectivity are selected by using the ACE criterion when the edges are added to form rings, and the error correction performance of LDPC codes is improved.

Description

technical field [0001] The invention relates to a method for constructing a check matrix of an LDPC code based on a protograph suitable for deep-space communication, which belongs to channel coding technology. Background technique [0002] Channel coding is a technology used to improve the transmission reliability of communication systems. Low Density Parity Check Codes (LDPC codes) were proposed by Gallager in 1962 and systematically discussed the coding method and probabilistic iterative decoding of the codes. code method, gave a detailed analysis of the decoding error probability, and pointed out that in the additive white Gaussian noise (AWGN) channel, the performance of this code is close to the Shannon limit and the implementation complexity is low, but due to the current level Due to the rapid development of linked codes and the limitations of software and hardware, LDPC codes have not entered people's sight. In 1981, Tanner proposed a method to represent LDPC codes ...

Claims

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Application Information

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IPC IPC(8): H03M13/11
CPCH03M13/11
Inventor 黄胜沈阳昝继航
Owner CHONGQING UNIV OF POSTS & TELECOMM