Robust sum-MSE transceiver optimisation for multi-user non-regenerative MIMO relay downlink systems

Presented is transceiver optimisation for multi-user non-regenerative MIMO relay downlink systems. By taking the channel uncertainties into account, a robust scheme is proposed to minimise the sum mean square error (SMSE) of the system under the power constraints, where the transceiver is obtained by using the Karush-Kuhn-Tucker conditions and realised through an iterative algorithm. Simulation results verify the robustness of the proposed scheme against the estimation errors.