Adaptive multistage space-time receiver for DS/CDMA systems

We propose a multistage joint adaptive array (AA) and spatial interference cancellation (IC) structure for a direct sequence code division multiple access (DS/CDMA) system. The structure utilizes both space and time processing to improve the performance of the base station receiver under the influence of multiple access interference (MAI) and in the absence of power control. The AA comprises a bank of temporal matched filters followed by a beamformer. IC is then used to remove the detected strong user from the received array input. This stage can be repeated for recover and remove more users. Computer simulation shows that, in the absence of power control, the proposed algorithm efficiently detects the weak user information at MAI levels of 30 dB where the conventional space-time structure fails.