Sum rate enhancement by maximizing SGINR in an opportunistic interference alignment scheme

In this paper, we consider an opportunistic interference alignment scheme exploiting multiuser diversity in the interference-limited uplink cellular networks. The spatial degrees of freedom afforded by multiple receive antennas are partitioned into the signal dimension and interference dimension. We propose a method to enhance the sum rate by maximizing the signal to generated interference and noise ratio (SGINR) in each user. When multiple antennas are available in each user, we also propose a transmit beamforming scheme at each user in the direction to further maximize SGINR. We show that the proposed methods greatly improve the sum rate compared to the conventional opportunistic scheme.