Timing estimation of code division multiple access multiuser communication

Multiuser detection for code division multiple access direct sequence spread spectrum (CDMA-DSSS) usually requires the timing information of all users. However, in earlier study of multiuser CDMA communication, the determination of the timing was not well understood. We derive the optimum timing estimator and conclude the necessity of separating the timing estimation process into acquisition and tracking. Moreover, we develop and analyze the reduced-complexity optimum timing estimator