A Gradient-Descent Weighted Sum MSE Transceiver Design for Multi-User Multi-Relay Downlink Systems

In this paper, a new transceiver design for multi-user multi-relay MIMO downlink channel is proposed. We derive the closed-form expressions for the gradients of the weighted sum-MSE with respect to the precoders and present a new transceiver design based on the gradient descent algorithm. The algorithm monotonically decreases the weighted sum-MSE and hence guarantees local convergence. Simulation results show that the proposed algorithm can generate good suboptimal solution with much faster convergence rate comparing to other algorithms.