Soft-output MMSE V-BLAST receiver with MMSE channel estimation under correlated Rician fading MIMO channels

For wireless multiple-input multiple-output (MIMO) communications systems, both channel estimation error and spatial channel correlation should be considered when designing an effective signal detection system. In this paper, we propose a new soft-output MMSE based Vertical Bell Laboratories Layered Space-Time (V-BLAST) receiver for spatially-correlated Rician fading MIMO channels. In this novel receiver, not only the channel estimation errors and channel correlation but also the residual interference cancellation errors are taken into consideration in the computation of the MMSE filter and the log-likelihood ratio (LLR) of each coded bit. More importantly, our proposed receiver generalizes all existing soft-output MMSE V-BLAST receivers, in the sense that, previously proposed soft-output MMSE V-BLAST receivers can be derived as the reduced forms of our receiver when the above three considered factors are partially or fully simplified. Simulation results show that the proposed soft-output MMSE V-BLAST receiver outperforms the existing receivers with a considerable gain in terms of bit-error-rate (BER) performance.