Low Overhead Linear Interference Alignment Algorithm for Two-cell MIMO Cellular Systems

The users’ performances are affected by the interferences in cellular systems. Especially for the users on the boundary whose communication qualities are poor. The interference alignment (IA) is a promising technology to effectively mitigate interferences and improve system throughput in wireless communications which has received lots of attentions. In this paper, we propose a linear IA algorithm that can achieve high degrees of freedom with less antennas for the users on the boundary of two-cell multiple-input multiple-output (MIMO) cellular systems. The algorithm uses the precoding vectors to eliminate the inter-user interference (IUI) and uses the interference suppression vectors to remove the inter-cell interference (ICI). Assuming each Base station equipped with M antennas communicate with K users each equipped with N antennas. Just let M=K and N=K+1, the proposed algorithm can complete downlink and uplink IA and can achieve a total DOF of 2K with low overhead. The algorithm doesn’t require inter-cell feedback in the downlink and it requires only a small amount of inter-cell feedback in the uplink. Simulation results show that the proposed algorithm can achieve better performance than the conventional schemes.