Inter-Relay Interference Cancellation for AF MIMO Two-Path Relay Systems

This paper considers amplify-and-forward, multiple-input multiple-output, two-path relay systems in which the inter-relay interference (IRI) between two relay nodes leads to a degradation of performance. To solve this issue, we propose two IRI cancellation schemes that exploit the orthogonal projection methods using multiple antennas at the relay nodes; the proposed schemes effectively remove the IRI by projecting it onto the null space of the effective inter-relay channel. Simulation results show that the proposed IRI cancellation schemes achieve close-to-optimal performance in average rate.