Two Convergence Enhancements for BICM-ID Using the Max-Log-MAP Criterion in MIMO Systems with Non-Gray Mappings

This paper presents two enhancements for improving the convergence behavior of bit-interleaved coded modulation iterative decoding (BICM-ID) in multiple-input multiple-output (MIMO) systems. As typical tree search based MIMO demapping algorithms for BICM-ID are based on the suboptimal Max-Log-MAP (maximum a-posteriori) criterion, the first enhancement aims at correcting the outputs of such MIMO demappers towards the optimal Log-MAP criterion. For the second enhancement, the deterministic annealing technique is applied to the iterative decoding process. Through simulation results, the efficiency of both enhancements has been demonstrated via the decoding performance and complexity.