Rate-compatible irregular repeat-accumulate codes for DVB-SH applications

Abstract

This paper presents a systematic rate-compatible (RC) irregular repeat-accumulate (IRA) low-density parity check (LDPC) family of codes for digital video broadcasting-satellite to handheld (DVB-SH) applications. Puncturing and extending of an optimized IRA mother code of rate 1/3 are used to obtain the full range of code rates. The main contribution of this paper is a simple, yet memory-efficient and modular, extending algorithm to obtain the lower code rates, based on a truncated Vandermonde matrix. In contrast to previously published extending methods, the one introduced in this paper does not use density evolution analysis, but instead achieves lower rate codes up to 1/5, by employing solely circulants and identity matrices in a deterministic structure. Compared to the standardized 3rd generation partnership project 2 (3GPP2) turbo codes, the proposed RC-IRA codes feature lower complexity decoding, that is beneficial from processing, power and memory constrained handheld devices. The performance of the proposed family of codes is evaluated for the additive white Gaussian noise (AWGN) channel with information block length k = 12282 bits. Computer simulation results demonstrate that, for a wide range of rates, the proposed RC-IRA family of codes performs very close to the 3GPP2 turbo codes, and outperforms the 3GPP2 turbo codes when the latter exhibit an error-floor at FER below 10-3 and at at BER below 10-5, apart from the case of rate R=1/5.