A new ToAs' CACFAR Wiener Rake Estimator for downlink mobile positioning in UMTS-FDD system

In this paper, we address the problem of Mobile Positioning and Tracking in the context of WCDMA mode of UMTS-FDD systems using signals' Time of Arrivals in the Downlink direction. A common method for ToA's estimation is correlation procedure between the received signal and delayed versions of the pilot sequence. This classical estimator suffers from the hearability and Near-Far problems, inherent to the WCDMA systems, and several improvements have been proposed in the literature to combat their effects. In this paper, we propose another ToA's estimator, based on Wiener Channel Estimator, and we combine it with a CACFAR detector in order to increase Fingers' probability of detection. Simulation results show that this new CACFAR Wiener RAKE Receiver operates better than the classical ones especially in the situations where the hearability problem has a hard effect on ToA's estimation.