Symbol-based BP detection for MIMO systems associated with non-binary LDPC codes

In this paper, an efficient iterative receiver for digital communication systems is investigated. It combines a Non-Binary Low-Density Parity-Check (NB-LDPC) decoder with a high-order constellation demapper and a Multiple-Input Multiple-Output (MIMO) detector. A suboptimal MIMO detector based on the Belief Propagation (BP) algorithm is investigated as an alternative to a Maximum Likelihood (ML) detector. Extrinsic information is exchanged between the detector and the decoder thanks to an iterative process. EXtrinsic Information Transfer (EXIT) charts enable to analyze the convergence behaviour of the proposed MIMO-BP detector. A suitable schedule for the different types of iterations is finally proposed to reduce the receiver latency and improve its error correction performance.