Soft-Output MMSE MIMO Detector Under ML Channel Estimation and Channel Correlation

As channel estimation errors are not taken into account by existing soft-output minimum mean square error (MMSE) multiple-input multiple-output (MIMO) detector, its performance can therefore be degraded under imperfect channel estimation. In this letter, we propose a novel soft-output MMSE MIMO detector under maximum likelihood (ML) channel estimation for a MIMO system with spatially correlated receiver and transmitter antennas. Our proposed detector takes both channel estimation errors and spatial correlation of antennas into account when constructing MMSE filter and computing log-likelihood ratio (LLR) of each coded bit. Simulation results show the proposed novel detector outperforms existing soft-output MMSE MIMO detector with considerable improvement.