Low-density parity-check accumulate codes

Abstract

This paper presents a class of high-rate codes called low-density parity-check accumulate (LDPCA) codes. The code design is the serial concatenation of an LDPC outer code and an accumulator with an interleaver. The iterative decoding for the LDPCA code design has complexity linear to the code length. When using regular LDPC codes with column weight 2, the proposed codes have low encoding complexity and are advantageous for hardware implementation. Simulation results show that the regular LDPCA codes have the same error performance with the regular LDPC codes at the waterfall region and outperform product accumulate codes at the error floor region. The investigation on weight distributions proves that regular LDPCA codes have the asymptotic minimum distance proportional to the code length. In addition, iterative decoding thresholds under density evolution are obtained with a Gaussian approximation.