A New Relay Precoding Scheme for Single RelayMulti-user MIMO System

In the single relay multi-user multi-input multi-output(MIMO) system,in order to overcome the inter-user interference,a new relay processing scheme which can be used to effectively suppress the inter-user interference is proposed in this paper.Firstly,the relay receives the signal by zero forcing(ZF)filtering.Secondly,the relay precoding vector is designed by using the signal-to-leakage-noise ratio(SLNR) maximization criterion,where a suboptimal relay precoding design is proposed since it is difficult to obtain the optimal relay precoding vector.The simulation results show that the new scheme can effectively suppress the inter-user interference in comparison with the relay terminal zero-forcing precoding,and at the same sum-rate,the power of the base stationis reduces more than 4 dB.So the proposed scheme is applicable.