Sectorized space-time multiuser detection for CDMA systems

Space-time multiuser detection (STMD) is an emerging technique for wideband CDMA mobile communication systems, where the problems of multiuser access interference (MUAI) and intersymbol interference (ISI) can be solved simultaneously. However, complexity becomes one of the key problems in its practical implementation because of the exponential increment of computation burden due to the increased number of users. In this paper, we propose the sectorized STMD scheme that confines detection within a given sector. In the proposed scheme, the number of users in the sector becomes smaller, and, consequently, the system complexity becomes lower. Due to the sectorized beamforming, the signal-to-noise ratios of the users' multipath rays are enhanced, leading to performance improvements in the signature waveforms' estimation and detection.