Systematic Repeat Accumulate codes for bit-interleaved coded modulation with iterative demapping over AWGN and Rayleigh fading channels

Repeat accumulate (RA) codes are the simplest one in the family of the capacity approaching codes, with great potential in the applications of modern communications systems. RA codes combine both the advantages of turbo codes and LDPC codes and are implemented using a turbo code representation to perform encoding and an LDPC code representation to perform decoding. The RA interleaver is chosen by random construction using the bit-filling method. In this paper, we investigate the performances of bit interleaved coded modulation (BICM) with iterative decoding and BICM with iterative decoding and demapping (BICM-ID) for bandwidth-efficient transmission. Both BICM and BICM-ID systems using systematic RA codes with Gray labelling on AWGN and Rayleigh fading channels are considered. Simulation results are presented for 16-QAM examples for rates frac12 and frac34.