Iterative Decoding for MIMO-BICM Systems with an EM-Based Signal Detector

We introduce an iterative receiver for the bit-interleaved coded modulated (BICM) symbols in multiple antenna systems. We propose a space-time signal detector based on the EM algorithm. The principal concept of the proposed receiver is the exploration of the neighbourhood for each transmitted symbol. Based on the neighbourhood subsets, the detector provides a close approximation of the a posteriori probability (APP) for each encoded bit. Accordingly, extrinsic information is extracted and exchanged between the EM-based detector and the MAP decoder in each iteration. The proposed receiver is scalable, in the sense that, the extent of the neighbourhood can be shrunk or expanded to provide a tradeoff between the computational complexity and bit error rate performance