Multiuser Timing Acquisition over Multipath Fading Channels

Existing subspace-based multiuser timing acquisition algorithms for code-division multiple access systems do not account for the multipath channel eeects satisfactorily. We present a new timing acquisition framework that leverages a canonical representation of the mobile wireless channel to fully exploit the underlying signal structure. The proposed approach promises improved performance based on three key advantages. First, it fully accounts for channel eeects in a parsimonious fashion. Second, it is noncoherent in nature since it only requires estimates of second-order channel statistics, as opposed to the actual channel coee-cients. Finally, it facilitates accurate modeling of the signal structure of the desired user, thereby yielding powerful interference suppression algorithms. The framework is applicable in both slow and fast fading scenarios and facilitates maximal channel diversity via joint multipath-Doppler processing. Preliminary results suggest that the resulting algorithms can deliver signiicantly improved performance at a lower complexity compared to existing methods.