Method for constructing LDPC codes and codes

Abstract

The invention discloses a method for generating LDPC codes. The method comprises the following steps that: step one, the size of a check matrix of the LDPC codes is set, wherein the check matrix is divided into an information portion and a check portion, wherein the check portion is obtained through dual diagonal matrix interweaving; step two, the information portion is divided into a plurality of sub information matrixes, wherein each sub information matrix comprise a plurality of circulatory arrays, and the column degree of each sub information matrix is determined, wherein the column degree is the number of non-zero circulatory arrays contained in the sub information matrix; step three, the positions of the non-zero circulatory arrays of each sub information matrix are determined; and step four, the offset of the non-zero circulatory arrays of each sub information matrix is determined. According to the method of the invention, on the one hand, the minimum distance of the codes is decreased through adopting an interweaving method, and on the other hand, optimal degree distribution and optimal circulatory matrix distribution can be researched by means of tools.

Description

technical field [0001] The present invention relates to a codeword construction method and a codeword generated according to the construction method, more specifically, to a codeword construction method and codeword of an LDPC code. Background technique [0002] The repeat-accumulate code is called RA (Repeat Accumulate) code for short. It was originally proposed as a type of turbo code, so it can be regarded as a serially connected turbo code, so it has the same advantage of low coding complexity as the turbo code. [0003] The RA code can also be regarded as an LDPC code, and can be described by a parity check matrix and a Tanner graph. From the check matrix, H=[H 1 h 2 ], usually H 2 Special structure with bidiagonal square matrix. The advantage of the LDPC code is that the decoding uses an iterative belief propagation algorithm, which can be fully parallelized and has low complexity. The RA code also has this advantage. [0004] The difference between the IRA (Irreg...

AI Technical Summary

Problems solved by technology

In particular, the double-diagonal structure of Structured-IRA makes the minimum distance of codewords very small, which greatly affects the performance of codewords and leads to the problem of error floor

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