MIMO Amplify-And-Forward Relaying: Spatial Gain and Filter Matrix Design

In this paper we investigate and analyze the performance of multi-antenna amplify-and-forward (AF) relays for a future cellular system where the destination and the source form a MIMO system. Two scenarios are analyzed, modelled and compared: the multi-relay scenario i.e. distributed relays, each equipped with at least one antenna; and the one-relay scenario i.e. a single relay in a sector where each relay is equipped with multiple antennas. The optimal filter coefficients applied at the relays are derived and recommended for both cases. The channel ergodic capacity and by product the throughput of the single link shows that the AF relay matched filter based performs best in the multi-relay scenario. On other hand the relay based singular value decomposition (SVD) is more suitable for the one-relay scenario.