Suboptimum multiuser detection of the QS-CDMA systems using antenna array

Multiuser detection has been an interesting topic because of its capability of eliminating multiuser interference and resistance to the near-far problem. The decorrelator approach has been investigated as a suboptimum multiuser detector for a low complexity receiver at the expense of the enhancement and correlation of noise. We consider a quasi-maximum likelihood (quasi-ML) detector in the reverse link system which uses antenna arrays in quasi-synchronous channels. It is shown that the performance of the system is better than that of 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