Abstract: The multibeam antenna array and the optimum multiuser detector are combined to reduced the near-far effects in asynchronous direct sequence spread spectrum multiaccess receiver. Based on this construction, the whole users in the cell canbe divided into groups by the multibeam of the antenna array, and then the optimum multiuser detectors are applied to each group of users to obtain optimum reception. We compare this approach with the conventional detector and the optimum multiuser detector in bit error rate and computational complexity. Results show that when using the structure we proposed, the computational complexity can be substantially reduced, and the performance can be improved, therefore the new approach is more feasible to implement.

Key words: CDMA, multiuser detector, antenna array