Adaptive interference coordination in multi-cell OFDMA systems

In multi-cell OFDMA systems, inter-cell interference can severely degrade the system throughput, particularly for cell-edge users. To mitigate the inter-cell interference problem, interference coordination is a promising approach that effectively restricts and allocates certain resources among users in different cells to minimize the effect of inter-cell interference. However, most approaches are studied for static user distribution/traffic load and usually require a centralizer controller to solve a complicated optimization problem. In this paper, we propose an adaptive and distributed interference coordination algorithm that can achieve an efficient frequency reuse for a given user distribution and traffic load. The proposed algorithm only requires minimal coordination between base stations and does not need any a priori frequency planning. To enable reduction in system optimization, we classify the users into two groups, namely cell-interior and cell-edge user groups. With such user group differentiation, we can efficiently decompose a multi-cell optimization problem into distributed optimization problems, which is composed of solving single-cell resource allocation problem.