A semiblind receiver based upon multiple constrained subspace MUD for long-code downlink multirate DS-CDMA systems

This paper presents a semiblind receiver based upon multiple constrained subspace multiuser detection for synchronous long-code downlink multirate DS-CDMA systems. The novel receiver adapts its fractionally-spaced equaliser (FSE) tap-weights based on two modes, namely training and decision-directed modes. Combination between the two modes is achieved by an adaptively mixing parameter which is adjusted in order to minimise a mixed error cost function. Specifically, detection of the desired user requires only the knowledge of the desired user´s spreading code. Simulation results show that the proposed receiver is capable of multiple access interference (MAI) suppression, multipath mitigation and improves signal-to-interference-plus-noise ratio (SINR) over existing receivers in both static and dynamic environments