Soft-output MIMO MMSE OSIC detector under MMSE channel estimation

In practical wireless multiple-input multiple-output (MIMO) communication systems, the channel estimation must be imperfect. Unfortunately, the channel estimation errors have not been taken into account by existing soft-output MIMO minimum mean square error (MMSE) ordering successive interference cancellation (OSIC) detectors when calculating the log-likelihood ratio of each coded bit, i.e., the soft information. As a result, the system performance can be degraded. In this paper, we propose a novel soft-output MIMO MMSE OSIC detector when MMSE MIMO channel estimation is applied. Based on the basic statistic properties of MMSE MIMO channel estimation, this proposed detector takes the channel estimation error into account in the computation of the MMSE filter and LLR of each coded bit. When compared with existing MIMO MMSE OSIC detectors, our simulation results show that the proposed novel detector can obtain considerable performance gain at the cost of negligible increase of complexity.