An iterative reliability-based decoding for LDPC coded modulation system

In this paper, A Belief Propagation concatenated Orderd-Statistic Decoder (BP-OSD) based on accumulated Log-Likelihood Ratio (LLR) is proposed for medium and short lengths Low Density Parity-Check (LDPC) codes coded Bit-Interleaved Coded Modulation (BICM) systems. The accumulated soft output values delivered by every BP iteration are used as reliability values of Soft-Input Soft-Output OSD (SISO-OSD) decoder and the soft output of SISO-OSD is used as a priori probabilities of the demodulator for the next iteration. Simulation results show that this improved algorithm achieves noticeable performance gain with only modest increase in computation complexity.