Joint Transmit/Receive MMSE Filtering for Single-carrier MIMO Spatial Multiplexing

Multiple-input multiple-output (MIMO) spatial multiplexing is a powerful technique to increase the transmission data rate. However, if MIMO spatial multiplexing is applied to single-carrier (SC) block transmissions, it suffers from the intersymbol interference (ISI) as well as the inter-antenna interference (IAI). In this paper, we propose a joint transmit/receive frequency-domain (FD) filtering using the channel state information (CSI) at both the transmitter and receiver for SC-MIMO spatial multiplexing. The transmit and receive FD filters are derived based on the minimum mean square error (MMSE) criterion. The proposed filters transform the MIMO channel to the multiple orthogonal channels (i.e., eigenmodes) so as to avoid the IAI. The ISI can be significantly suppressed by applying the joint transmit/receive MMSE based frequency-domain equalization (MMSE-FDE) to each eigenmode. The throughput performance achievable with the proposed joint transmit/receive MMSE-FD filtering is evaluated by computer simulation. It is shown that the proposed method outperforms the conventional receive MMSE-FD filtering which uses the CSI at the receiver only. Keywords; Single-carrier transmission, MIMO spatial multiplexing, MMSE filtering