Uplink performance enhancement for WCDMA systems through adaptive antenna and multiuser detection

Abstract

Multipath fading and multiple access interference (MAI) are the major constraints on the performance of DS/CDMA systems. Antenna arrays and multiuser detectors have been considered to increase the system capacity through mitigation of such impairments. Multiuser detectors have the capability of eliminating MAI, the near-far problem and providing a significant capacity increase. In order to gain from the enhancements of both: multi-user detection and adaptive antenna, we propose in this paper to combine both schemes for an asynchronous WCDMA system. The performance of the combined scheme is evaluated for the uplink over the Gaussian channel and the UMTS frequency selective Rayleigh fading channel. We make a comparison of the most promising multiuser structures and the recursive least square algorithm to control the beamformer.