Suboptimum multiuser detection of DS/CDMA systems using antenna arrays in asynchronous channels

We consider quasi maximum likelihood (quasi-ML) detection in the reverse link system which uses antenna arrays in asynchronous channels. It is shown that the proposed quasi-ML detector can be regarded as a beamformer followed by a decorrelator, that the proposed system performs better than the conventional decorrelator, and that the performance gain over the conventional decorrelator system increases as the number of active users and number of antenna arrays increase