A space-time receiver for asynchronous DS-CDMA systems based on Kalman filter

A new Kalman filter based space-time (S-T) receiver is proposed in this paper. By modeling an asynchronous CDMA system as a first-order state-space model, we can recursively obtain the finite-length linear minimum mean square error (LMMSE) receiver, which provides the best multiple access interference (MAI) cancellation among all the linear filters. Further interference suppression is provided by the spatial beam-former. The proposed receiver overcomes the near-far problem existing in the conventional joint S-T RAKE receiver. Simulation results demonstrate that the proposed Kalman filter based S-T receiver significantly outperforms the conventional joint S-T RAKE receiver.