Optimization of a coherent decision-directed timing-error-detector for multi-user DS-CDMA applications

In this paper, we consider a direct-sequence code-division multiple-access systems operating in downlink. We propose to improve the performances of a conventional decision-directed (DD) timing synchronizer, i.e. the early-late algorithm, by means of a prefilter which is optimized for a multi-user scenario. Simulation results show improved tracking performances and a better bit error rate (BER) compared to the standard early-late algorithm.