Low-Complexity and Full-Diversity MIMO Detection Based on Condition Number Thresholding

In this paper, we consider MIMO spatial multiplexing systems and elaborate the impact of the channel condition number on the performance of ML and ZF detection. In particular, we show that for channels with bounded condition number ZF detection achieves the same diversity as ML detection. Motivated by this, we propose a novel threshold receiver that uses simple ZF detection for well-conditioned channels and ML detection for poorly conditioned channels. We show that this receiver achieves full diversity and we provide an upper bound on its SNR gap to ML detection. We further investigate cost-reduced versions of the threshold receiver and examine their performance in terms of simulation results.