A new low-complexity demapper for high-performance iterative MIMO: information-theoretic and BER analyses

Space-time bit interleaved coded modulation with iterative detection has been recognized as a method for achieving near-capacity performance using multiple-input multiple-output (MIMO) systems. However, the maximum-likelihood/joint-detection, required for this method, exhibits prohibitive implementation complexity at high rates (≥15 bps/Hz). With a view to enabling practical implementations of high spectral-efficiency wireless communications, this paper introduces a new single-stream detection approach using spatial-filtering and soft-cancellation. This method also exhibits superior performance relative to the conventional multi-stream detection approach as long as there are as many receive elements as there are transmit streams. The proposed method is evaluated in terms of bit error rate performance and information-theoretic considerations using an EXIT (extrinsic information transfer) chart method.