Multiuser Adaptive MMSE Receiver using Multiple Antennas for Asynchronous W-CDMA Systems in Multipath Fading Channels

The performance of multiuser adaptive minimum mean square error (MMSE) receiver combined with multiple antennas is investigated for wideband code division multiple access systems (W-CDMA) in multipath fading channels. In the adaptive implementation of the receiver, performance of various algorithms like least mean square (LMS), normalized least mean square (NLMS), recursive least square (RLS) and the newly proposed affine projection adaptive (APA) filtering algorithm is considered. With the use of spatial diversity (by having multiple antennas at the receiver) significant improvement can be achieved in the output signal–tointerference-and-noise ratio (SINR). The effect of fading correlation between antenna elements (which is a function of antenna spacing, angle of arrival, angle spread, and carrier frequency) on the performance is evaluated using simulation.