Pii: S0140-3664(00)00202-4

This paper introduces a location-based locating strategy for Personal Communication Services (PCS) systems. In the proposed scheme, location updates are based on the value of a movement counter. The update of the movement counter is based on information on the locations visited by a mobile terminal (MT) since the last location update. In particular, the cell identi®ers and the corresponding movement counter values are maintained in the MT for a part of the visited cells since the last location update. When the MT enters a cell whose identi®er is not stored in the MT, the movement counter increases by one. If the movement counter reaches the update threshold, a location update is triggered; otherwise, the cell identi®er and the corresponding movement counter value are stored in the MT. When the MT enters a cell whose identi®er is in the MT, the movement counter is assigned with the counter value kept in the MT for this cell, and all cells with greater counter values in the MT are removed. The proposed scheme allows the dynamic selection of the update threshold according to each user's calling and mobility patterns. Analytical and simulation models have been developed to compare the proposed scheme with both the movement-based scheme and the distance-based scheme. Results demonstrate that when the call-to-mobility ratio (CMR) is low, the proposed scheme can achieve a signi®cant cost reduction compared to the movement-based scheme. For example, when the CMR is 0.01, a savings of around 25% in the optimal total cost per call arrival is achieved with the proposed scheme. Moreover, the proposed scheme is easier to implement than the distance-based scheme. q 2000 Elsevier Science B.V. All rights reserved.