A METHOD OF AND APPARATUS FOR TRACKING PROPAGATION DELAY BETWEEN A BASE STATION AND A SUBSCRIBER UNIT

摘要

A method of and apparatus for tracking propagation delay between a base station and a subscriber unit is described. The method and apparatus may be used in performing an efficient soft handoff in a cellular telephone system. In one embodiment a round trip delay between a base station (32a, 32b) and a subscriber unit (30) is tracked. Changes in the round trip delay at the base station (32a, 32b) are monitored, and updates sent to a base station controller (36) when the delay changes by more than a predetermined amount. Using round trip delay from a first base station and a pilot PN code phase for a pilot received from a second base station, an estimated arrival state of a reverse link signal from the subscriber unit (30) to the second base station is calculated. The estimated arrival state aids acquisition of the reverse link signal by the second base station.