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.