Fast switched-beam beamforming for optimal selection combining in frequency selective fading CDMA channels

In previous work we emphasized the advantages of using a fast switched multibeam antenna for channel estimation in multipath Rayleigh flat-fading code division multiple access (CDMA) communication channels. In this paper we investigate the benefits of designing fast switched-beam antenna systems that maximize the signal to interference plus noise ratio (SNIR) of the desired user, when the signals are subject to frequency selective fading. The diversity offered by multipath propagation is exploited using selection combining. The aim is to, given a set of predetermined beam patters, select the chip rate switching beam sequence that will maximize the signal strength of the desired user, while minimize the interference from all other users.