A Novel Interference Alignment Scheme With a Full-Duplex MIMO Relay

Recently, interference alignment (IA) has attracted great attention due to its superior performance. However, to achieve IA, users have to bear heavy burdens, such as providing enough dimensions, acquiring global channel statement information and affording high computational complexity, which makes IA difficult to apply in practical networks. Therefore, in this letter, we propose a centralized IA (CIA) scheme, where a relay is employed to off-load the burden of mobile users, i.e., interferences are aligned only by the relay. Furthermore, considering that the receivers still need to zero-force the aligned interference, another scheme called centralized zero-forcing (CZF) is proposed to further reduce the burden of the receivers. Closed-form solutions and feasibility conditions of both schemes are presented. Simulation results are presented to validate the effectiveness of the proposed schemes.