This paper proposes an efficient linear processing for half-duplex amplify-and-forward multiple input and multiple output relay system. We consider a relay assisted multi-user multiple input and multiple output (RA-MU-MIMO) system. Each node of the network is equipped with multiple antennas and information is assisted by a single MIMO relay. An efficient linear processing is applied at the relay node to improve overall system performance. A Matched filter is used as relay receiving beamforming and per-antenna-signal to leakage plus noise ratio (PA-SLNR) maximization is applied as the relay downlink precoding, to control interference among multiple users. Monte Carlo simulation confirms better performance in terms of ergodic capacity offered by the proposed scheme. © 2014 IEEE.