Low Complexity Encoder of High Rate Irregular QC-LDPC Codes for Partial Response Channels

Abstract

High rate irregular QC-LDPC codes based on circulant permutation matrices, for efficient encoder implementation, are proposed in this article. The structure of the code is an approximate lower triangular matrix. In addition, we present two novel efficient encoding techniques for generating redundant bits. The complexity of the encoder implementation depends on the number of parity bits of the code for the one-stage encoding and the length of the code for the two-stage encoding. The advantage of both encoding techniques is that few XOR-gates are used in the encoder implementation. Simulation results on partial response channels also show that the BER performance of the proposed code has gain over other QC-LDPC codes.

Keywords

• circulant permutation matrices
• high rate irregular QC-LDPC codes
• low encoding complexity
• partial response channels
• redundant parity bits