Synchronization over rapidly time-varying multipath channels for CDMA downlink receiver in Time-Division mode

In this paper, we consider a Time-Division CDMA system operating in downlink mode in a multi-user multipath channel scenario. In order to implement RAKE reception, the delays and the phases of the different paths have to be estimated and the estimates have to be updated. In the context of burst transmissions, the delays do not vary during a burst and only the phases have to be tracked. In this paper we investigate the issue of phase tracking over rapidly time varying multipath channels. We propose a new version of a conventional phase recovery loop that can cope with unresolvable paths. The optimization is based on the concept of prefiltering. The analysis shows improved tracking performance in comparison to the standard phase recovery algorithm.