Effective SINR Computation for Maximum Likelihood Detector in MIMO Spatial Multiplexing Systems

This paper studies the computation of postprocessing signal-to-interference plus noise ratio (SINR) for maximum likelihood detector (MLD) in multiple-input and multiple output (MIMO)-orthogonal frequency division multiplexing (OFDM) spatial multiplexing systems. We derive an effective post-MLD SINR for each spatial stream, which is computed as post minimum mean-squared error (MMSE) SINR plus gain factor, where the gain factor is adaptively computed based on the instantaneous channel and modulation format of interfering streams. The post-MLD SINR is then applied to modulation and coding scheme (MCS) selection in adaptive modulation and coding. Simulation results show that the MCS selection using proposed post-MLD SINR can achieve throughput performance close to that of the optimum approach, and considerable gain can be achieved over linear-MMSE receiver.