Approximate comparative analysis of interference suppression performance between antenna and beam selection techniques

Multiple antenna systems can greatly improve the performance of wireless systems by providing better link quality, capacity and immunity to interference. A very simple structure for smart antennas is a fixed beamforming network (FBN) with beam selection. In Y.S. Choi and S.M. Alamouti (2004) the performance of antenna and beam selection/combining techniques are compared. The channel model in that paper is a statistical, clustered propagation model in a correlated Rayleigh fading channel. In this paper we derive the approximate density function of the signal-to-interference-and-noise power-ratio (SINR) of beam selection with eigen-beamforming. We also analyze the outage probability and capacity of beam selection with a fixed beamforming network (FBN) with correlated fading between the antennas. We compare the performance of this system with antenna selection avid independent fading between the antennas. We also investigate the impact of erroneous beam or antenna selection. We show that beam selection outperforms antenna selection in the presence of interference