Bit-Interleaved Coded Modulation for the Relay Channel Using Bilayer LDPC Codes

This paper describes a coding scheme for approaching the maximum theoretical decode-and-forward rate for the relay channel in the high signal-to-noise ratio (SNR) regime. The proposed scheme is based on a concatenation of bit-interleaved coded modulation (BICM) and a specially designed bilayer low-density parity-check (BLDPC) code that works simultaneously at two different SNRs. It is shown that the proposed BICM-BLDPC scheme provides a close-to-optimal performance for the relay channel at high SNRs, with a gap of 0.5 dB to the theoretical limit, at a bit error rate of 10^-1.