Research On Transceiver Design For MIMO Relay Systems

MIMO and relay are key technologies in future mobile communication.MIMO relay systems,which incorporate relaying technology in MIMO systems,have attracted considerable attention in recent years due to their ability to extend system coverage and improve link reliability as well as spectral efficiency.This paper mainly investigates the transceiver design for non-regenerative MIMO relay systems.Three systems are studied in this paper,which are single user,multi-user MIMO relay downlink and uplink systems.First,a decomposed transceiver design scheme is proposed for single user MIMO relay systems,where the relay processing matrix is decomposed into the product of a signal estimating matrix and a precoding matrix.By doing so,the whole system can be decomposed into two point-to-point MIMO systems,then the transceiver can be individually designed for the first and second hop.This decomposed method can also be applied to multi-user MIMO relay downlink systems,where the whole system can be decomposed into a point-to-point and a point-to-multipoint MIMO system.Simulation results of BER performance demonstrate the effectiveness of the proposed algorithm.Finally,in multi-user MIMO relay uplink systems where each user applies space multiplexing,the optimal relay processing matrix and the base station detecting matrix are derived based on the MMSE criterion,which can be solved by an iterative method.