New Opportunistic Interference Alignment Schemes in MIMO Interfering Broadcast Channels

In this paper, we propose two new opportunistic interference alignment (OIA) algorithms which combines OIA technique with opportunistic beamforming for three-transmitter multiple-input multiple-out (MIMO) Interfering Broadcast channels (IFBCs). Based on the existing OIA scheme, the signal-to-leakage of interference ratio (SLIR) user selection (US) scheme is proposed first which takes both the maximization of the desired signal power and minimization of the received leakage of interference that decides the achievable sum rate and bit error rate (BER) performance directly into consideration while the existing OIA does not care. In order to further improve the BER performance of the system, mean square error based OIA (MSE-OIA) is presented. Simulation results show that the proposed two schemes outperform the existing OIA scheme significantly in terms of both sum rate and BER performance.