Interference Alignment for the Multiple-Antenna Amplify-and-Forward Relay Interference Channel

Interference alignment is a multiplexing gain maximizing technique for the single-hop interference channel. It can be extended to multi-hop interference channels, where relays aid transmission. In addition to coverage extension and capacity enhancement, relays allow the system to achieve higher multiplexing gains. This paper proposes a relay-aided interference alignment algorithm for the multiple-antenna amplify-and-forward relay interference channel. This algorithm relies on a connection between mean square error and achievable rate to solve the end-to-end sum-rate maximization problem. Numerical results show that the proposed algorithm outperforms other strategies in terms of both end-to-end sum-rates and multiplexing gains.