Interleaver Design for Small-Coupling-Length Spatially Coupled Protograph LDPC-Coded BICM Systems Over Wireless Fading Channels

Abstract

As a class of convolutional error-correction codes (ECCs), spatially coupled protograph low-density parity-check (SC-PLDPC) codes with a sufficiently large coupling length can approach the channel capacity under belief propagation (BP) decoding. However, such codes suffer from poor performance in the case of small coupling lengths. To address the above weakness, we investigate the optimization and analysis of SC-PLDPC-coded bit-interleaved coded modulation (BICM) systems over Rayleigh fading channels. Specially, inspired by the unequal-error-protection (UEP) mechanism of M-ary phase-shift keying/ quadrature amplitude modulation (M-PSK/QAM), we put forward a novel interleaver design scheme, referred to as spatial position match mapping (SPMM) scheme. Based on the mutual information (MI) analysis, the proposed interleaver can be used to significantly boost the performance of the SC-PLDPC codes in BICM systems. Furthermore, we propose a block-scheduling protograph-based extrinsic information transfer (BS-PEXIT) algorithm to estimate the convergence performance (i.e, decoding threshold) of the SPMM-aided SC-PLDPC codes in BICM scenarios. Simulation results are well consistent with the theoretical analyses, and show that the proposed SPMM-aided SC-PLDPC-coded BICM systems are superior to the state-of-the-art counterparts. INDEX TERMS Spatially coupled protograph low-density parity-check (SC-PLDPC) codes, bit-interleaved coded modulation (BICM), interleaver, wireless fading channels.

Computing Algorithms for LDPC Coded Internet-of-Things

“…As a class of capacity-approaching codes, low-density parity-check (LDPC) codes have been widely adopted in emerging wireless communication systems to achieve reliable information transmission [9]- [11]. Since the power and the computing capability of the nodes in IoT are limited, new codes and modulations should be developed [1], [6], [12].…”

Design of a Labeling Scheme for 32-QAM Delayed Bit-Interleaved Coded Modulation

“…Bit-interleaved coded modulation (BICM) [ 1 ] has been widely used in practical systems for its simplicity. It is a bandwidth efficient coded modulation scheme and has been well investigated in point-to-point communications [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Compared to trellis-code modulation [ 8 ], BICM introduces a random interleaver between the encoder and modulator, which enables researchers to design the encoder and the modulator separately [ 7 ].…”