An interference alignment scheme for sum rate enhancement in multi-cell communication systems

In this paper, maximum rate interference alignment (MR-IA) algorithm is proposed for multi-cell downlink interference systems. Based on the researches on distributed interference alignment (IA) algorithms, the proposed algorithm can further enhance the sum rate. In this scheme, the precoding matrices are optimized by searching precoding alone the gradient ascent direction of throughput. In this process, the step length is decreased with multiplying a parameter smaller than 1, which leads to the degradation to rank constrained rank minimization interference alignment (RCRM-IA) algorithm. Thus, the algorithm can attain interference alignment as well as the throughput improvement eventually. Simulation examples are provided showing that the proposed algorithm can enhance the sum rate obviously compared with the conventional algorithms.