A Clustered Alignment-Based Interference Management Approach for Large OFDMA Cellular Networks

Spatial interference alignment among a cluster of base stations is considered as a technique to mitigate inter-cell interference in the downlink of a large cellular network using OFDMA. We study the case where a subset of base stations inside a network collaborate to align interference. A novel constructive method for finding the interference alignment solution is proposed for the case where the number of transmit antennas equals the number of receive antennas (NT = NR = N ), the number of transmitter-receiver pairs equals K = N + 1, and all interference alignment multiplexing gains are one. We also derive an expression for the mutual information achieved by clustered base station cooperation together with a zero-forcing receiver. Numerical performance results with throughput gains of up to 30% with respect to the non-cooperating base stations case are demonstrated for users located in the central area of the cells. Those results provide insight into the applicability of interference alignment methods in upcoming cellular networks such as UMTS LTE-Advanced.