US 2008/0168324 A1 · Basic Matrix Based on Irregular Ldpc, Codec and Generation Method Thereof

Abstract

Basic matrix based on irregular LDPC codes, codec and generation method thereof. The codec includes an encoding/decoding operation module and a basic matrix storage module. In the stored basic matrix Hb, for all girths with length of 4, any element of i, j, k or l constituting the girths in anti-clockwise or clockwise always satisfies inequality: mod(i−j+k−l, z)≠0, wherein z is the extension factor. When generating the basic matrix, firstly the number of rows M, number of columns N, and weight vectors of the rows and columns are determined, an irregularly original basic matrix is constructed; then the position of ‘1’ is filled by a value chosen from set {0, 1, 2, . . . , z−1} to obtain the basic matrix Hb, which is made to satisfy the above-mentioned inequality. The basic matrix Hb obtained by storing, which is configured with corresponding encoding/decoding operation module, constitutes the desired encoder/decoder. The encoder/decoder according to the present invention can effectively eliminate error-floor phenomenon of LDPC codes and accelerate the falling speed of BER curve.

Claims16

Dependent claims

A basic matrix of irregular low density parity check (LDPC) codes, wherein the basic matrix Hb consists of a M×(N−M) block A corresponding to information bits and a M×M block B corresponding to check bits, characterized in that, the matrix also meets the following condition:

for all girths with length of 4 in the basic matrix Hb, any element of i, j, k and l constituting the girths in anti-clockwise or clockwise always satisfies an inequality:
mod(i−j+k−l, z)≠0, wherein mod is modular operation, z is extension factor, and wherein said block B corresponding to check bits applies a quasi lower triangular structure.

An encoder based on irregular low density parity check codes comprising an encoding operation module, characterized in that it also comprises a basic matrix storage module, wherein:

said basic matrix storage module is used to store a basic matrix made of the M×(N−M) block A corresponding to information bits and the M×M block B corresponding to check bits. In said basic matrix, for all girths with length of 4, any element of i, j, k and l constituting the basic matrix in anti-clockwise or clockwise always satisfies the inequality:
mod(i−j+k−l, z)≠0, wherein mod is modular operation, and z is extension factor,
said encoding operation module is used to perform an encoding operation to obtain a N bit code word from source data of N−M bit based on said basic matrix,
wherein an extension module is also included to extend said basic matrix according to the extension factor and a basic permutation matrix to obtain a (M×z)×(N×Z) parity check matrix of low density parity check codes, and said encoding operation module performs encoding based on the parity check matrix obtained from extension of said basic matrix,
wherein said basic matrix also satisfies the following condition:
said block B corresponding to check bits applies a quasi lower triangular structure.

3 more elements

Dependencies are inferred from the claim text.

Basic Matrix Based on Irregular Ldpc, Codec and Generation Method Thereof

Life of this patent

Basic Matrix Based on Irregular Ldpc, Codec and Generation Method Thereof

Life of this patent

Abstract

Claims16