Low complexity asynchronous DS-CDMA detectors

Near-far resistant multiuser-detectors for an asynchronous direct-sequence code-division multiple access (DS-CDMA) system, which do not need the code-matched filter outputs from all users are presented. Two complex-valued, discrete-time vector models for the system are formulated. Detectors for both models, that work on blocks of data of M symbols are considered. The problem of estimation of the bits is posed in a least squares sense and as a minimum mean squared error problem. The performance of the detection algorithms is investigated by computing the BER (bit error rate) on simulated data. Comparisons with traditional detectors is also carried out. It is shown that detectors based on the compact vector model performs slightly worse than detectors based on the more complex vector model