Opportunistic interference alignment in cellular downlink

Interference alignment is known to be degrees of freedom optimal for the K-user interference channel. As a result, many alignment-based schemes have been developed in literature. However, most schemes are not easy to implement due to the requirements for a large number of dimensions and an extensive exchange of channel state information. This paper eliminates these requirements by combining interference alignment with the idea of opportunistic scheduling to facilitate alignment in the cellular downlink by opportunistically selecting users and harnessing the multi-user nature of cellular scheduling. Specifically, the opportunistic interference alignment scheme requires no channel state information at the base station transmitters. Simulation results show significant improvement in throughput of cell-edge users without any degradation in performance of other users.