Method for constructing quasi-cyclic low-density parity check (LDPC) code

Abstract

The invention discloses a method for constructing a quasi-cyclic low-density parity check (LDPC) code. A check matrix H (J, K, Z)=[HmzH8 3] of the quasi-cyclic LDPC code constructed by the method is nonsingular and consists of two parts, namely a nonsingular quasi-cyclic square matrix Hmz of which the cycle length is 6 and the row weight is 3 and a quasi-cyclic matrix H8 3 of which the cycle length is 8 and the row weight is 3, wherein the quasi-cyclic square matrix Hmz comprises J*Z lines and J*Z rows and consists of J*J cyclic shift square matrixes of which the number of dimensions is Z*Z; the quasi-cyclic matrix H8 3 comprises J*Z lines and (K-J)*Z rows and consists of J*(K-J) cyclic shift square matrixes of which the number of dimensions is Z*Z; and the code length and code rate of the constructed quasi-cyclic LDPC code are K*Z and (K-J) / k respectively. A generator matrix of the LDPC code has the characteristics of structuration and sparseness; and all-nonzero matrixes in the samerow group of the generator matrix meet the relation of cyclic shift, so the complexity of an encoder in the aspects of storage space and the like is lowered. A simulation result indicates that the quasi-cyclic LDPC code constructed by the method has high decoding performance.

Description

technical field [0001] The invention relates to a construction method of a quasi-cyclic low-density parity check code suitable for a cooperative relay strategy of joint network coding and channel coding, and belongs to the technical field of communication. Background technique [0002] In recent years, low-density parity-check codes (LDPC codes) and network coding techniques have gradually become research hotspots in the field of communication. LDPC code is currently the codeword closest to the Shannon limit in the world, and is generally considered to be a favorable competitor for channel coding schemes in fourth-generation mobile communications. Quasi-cyclic LDPC code is a structured LDPC code, which has been adopted by standards such as IEEE 802.11n and IEEE 802.16e. The network coding technique can bring diversity gain while improving the throughput performance of the communication system. In general, network coding technology and LDPC codes operate independently. Netw...

AI Technical Summary

Problems solved by technology

In addition, randomly constructed LDPC codes are not suitable for cooperative relay strategies based on network coding

The check matrix and generator matrix of randomly constructed LDPC codes are not structured, and the number of non-zero elements in the generator matrix far exceeds the number of zero elements, and the coding complexity is very high

However, the excellent decoding performance of LDPC codes can only be reflected when the code length is longer (greater than 1000). Long code length means that there are a large number of cooperative relay users. High requirements are put forward for decoding, etc., and the complexity of the system is too high, which limits its practicability

Images