Irregular quasi-cyclic low-density parity check code construction method

Abstract

The invention relates to an irregular quasi-cyclic low-density parity check code construction method, which comprises the following steps: determining line parameters and row parameters of a basis matrix of a check matrix to be designed; traversing all rows by lines, and generating a matrix H1 by using a Hanoi tower sequence structure; obtaining a cyclic permutation matrix offset value of the position according to a formula pj, l = f (j + l) + j, and placing the cyclic permutation matrix offset value into a position at line j and row 1 of the constructed matrix; forming the matrix H1 by all the cyclic permutation matrix offset values; constructing an irregular check matrix H2 by using a PEG (progressive edge-growth) algorithm, generating a matrix I in which all numbers are 1, and carrying out subtraction on the matrix H2 so as to obtain a matrix H3; carrying out a cyclic shift parameter replacement operation on the matrix H2 so as to obtain the base matrix; and selecting a unit matrix as a cyclic shift matrix, carrying out a cycle shift operation on the unit matrix by referencing the elements of the base matrix, and expanding the base matrix so as to obtain the check matrix. The method disclosed by the invention effectively reduces the storage complexity of LDPC (low-density parity check) code in the process of construction.

Description

technical field [0001] The present invention relates to the communication field, in particular to a method for constructing an irregular quasi-cyclic low-density parity check ("QC-LDPC" for short) code. Background technique [0002] LDPC code is Low Density Parity Check Code (Low Density Parity Check Code, LDPC), which is a kind of linear block code with sparse check matrix proposed by Robert G. Gallager. Afterwards, MacKay and Neal et al. re-studied LDPC codes and proposed a feasible decoding algorithm for LDPC codes, thus further discovering the good performance of LDPC codes. [0003] At present, LDPC codes have been widely used in deep space communication, optical fiber communication, satellite digital video and audio broadcasting and other fields. LDPC code has become a strong competitor of the fourth generation mobile communication system (4G), and the coding scheme based on LDPC code has been adopted by the next generation satellite digital video broadcasting standar...

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Problems solved by technology

[0008] The analysis found that its check matrix storage complexity is JL, and the LDPC code is randomly constructed. It still has a high storage complexity. At the same time, this scheme does not reflect the performance of the LDPC code close to the Shannon limit. The main reason is that there is no effective control of the short loop with a length of 4.

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