A New Turbo Equalizer Conditioned on Estimated Channel for MIMO MMSE Receiver

In this letter, we propose a new equalization scheme based on minimum mean-square error (MMSE) criteria with a channel estimation error. Different from the existing work on linear MMSE receivers, we consider both the a priori information and channel estimation error in the equalizer design, and re-derive the soft output extrinsic information used for the channel decoder. Conditioned on the estimated channel, we developed the new autocorrelation and covariance matrix of the received vector, which are used to derive the equalizer coefficients. One of our major contributions of this letter is a general expression of the MMSE-based turbo equalization to account for both the channel estimation error and the a priori information, which is not presented in the literature. Simulation results show that significant performance improvement can be achieved with the proposed turbo equalizer.