MMSE receive filtering for precoded MIMO systems

MIMO precoding matches the transmission to channel conditions in order to reduce or eliminate interference at the receiver. In this paper, we are interested in the case where the receiver is also equipped with a linear processor, specifically an MMSE filter. We analyze the effect of the MMSE receive filter on the performance of a variety of MIMO precoders. It is shown that receive-side MMSE equalization can remove the error floors that sometimes appear with regularized zero-forcing precoding and matched-filter precoding. It is also shown that using the MMSE filters at both the transmitter and receiver can achieve the full spatial diversity when the spectral efficiency R (b/s/Hz) is below a certain threshold.