Adaptive space-time MMSE receivers in DS CDMA systems

An adaptive space-time MMSE receiver is proposed for asynchronous DS/CDMA by combining an adaptive antenna array and adaptive filter to take advantage of combined filtering in bdh the space and time domains. The receiver can provide a better suppression and a reduced sensitivity to co-channel interference in a near-far environment. The convergence of the LMS adaptation procedure toward the Wiener optimum solutions of the adaptive array and adaptive filter is presented based on minimisation of MSE. Simulation results show that considerable improvement in convergence, steady-state MSE as well as BER over the existing single-antenna MMSE receiver can be achieved.