Joint MIMO Filter-and-Forward Relay and Base Station Post-Processing for Uplink CoMP Reception with Frequency-Selective Channels

In this paper, we study the sum mean square error (SMSE) performance of all users by applying joint MIMO filter-and-forward relay and post-processing at base stations (BSs) for uplink coordinated multi-point (CoMP) reception in case of users-to-relay and relay-to-BSs frequency-selective fading channels. In order to combat the interference due to frequency-selectivity of channels, MIMO relay passes its received signals through a finite impulse response (FIR) filter. For further reducing SMSE, each BS applies a post-processing to its received signals. The goal is minimizing the SMSE subject to transmitted power constraint of MIMO relay. An iterative algorithm is proposed to jointly optimize the filter matrices of the relay and post-processing matrices of the coordinated BSs. Simulation results show effectiveness of the proposed scheme in comparison with previous schemes utilizing joint precoding relay and post-processing BS.