MMSE based precoding design for MIMO shared-relay systems

In this paper, we address the joint precoding design at both the relay and destination nodes for non-regenerative multiple-input multiple-output (MIMO) shared-relay systems. The minimum mean-squared error (MMSE) of symbol estimation at the destination nodes is adopted as our design criterion. In particular, for the two decoding schemes which are the separate decoding scheme and the joint decoding scheme, we derive the closed-form expressions of the transceiver and develop the iterative methods to solve the nonconvex joint relay and receiver optimization problems. Simulation results demonstrate that the proposed schemes perform better than the existing technique in terms of both MSE and bit error rate.