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.

Design of Efficiently Encodable Rate-Compatible LDPC Codes Using Vandermonde Extension Matrices

“…5] of at least 8, leading to improved error-correction capabilities. Moreover, based on simulation results using the extending structure of [18], the two additional circulants, i.e. A 27 and A 64 , added at the last two levels of extension, enhance the codes' error correcting performance by approximately 0.1 and 0.2 dB at a FER of 10 −2 and at a bit error rate (BER) of 10 −5 , respectively.…”

“…lower than 2/5). In particular, we extend our preliminary work presented in [18] by optimizing the design of the extended matrices for short and medium block length codes. A generic deterministic extending algorithm for designing efficiently encodable RC-LDPC codes from an IRA mother code using circulants shifted according to a VM is introduced.…”

“…In the past, relatively few contributions concerning deterministic [5,6,18,19] or optimal [20] extending for RC-LDPC and RC-IRA codes have been published. In [5], an extending technique was proposed for obtaining lower-rate regular RC-LDPC codes from a moderate rate LDPC mother code using weight-3 columns and very sparse sub-matrices.…”

“…In addition, the constructed RC-LDPC codes with low-triangular structure have higher encoding complexity than RC-IRA codes with dual-diagonal structure. In [18], we have constructed a systematic RC-IRA family of codes with information block length k 0 = 12 282 bits for Digital Video Broadcasting-Satellite to Handheld (DVB-SH) applications, by employing an extending structure based on a truncated VM. In a recent paper [19], two generic deterministic extending approaches for RC-IRA codes based on identity matrices (extended-identity) and matrix permutations (extended permuted) were introduced.…”

Cooperative DVB-SH satellite broadcasting systems with rotated signal constellations

“…Following the DVB-SH implementation guidelines [7] with respect to the channel coding, the 3GPP2 turbo code [32][33][34] has been employed in the system under investigation. The main features of this code are:…”