A location-based mobility tracking scheme for PCS networks

This paper introduces a location-based locating strategy for Personal Commu nication Services (PCS) systems. In the proposed scheme, location updates a re based on the value of a movement counter. The update of the movement cou nter is based on information on the locations visited by a mobile terminal (MT) since the last location update. In particular, the cell identifiers an d the corresponding movement counter values an maintained in the MT for a p art of the visited cells since the last location update. When the MT enters a cell whose identifier is not stored in the MTI the movement counter incr eases by one. If the movement counter reaches the update threshold, a locat ion update is triggered; otherwise, the cell identifier and the correspondi ng movement counter value are stored in the MT. When the MT enters a cell w hose identifier is in the MT, the movement counter is assigned with the cou nter 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 selec tion of the update threshold according to each user's calling and mobility patterns. Analytical and simulation models have been developed to compare t he proposed scheme with both the movement-based scheme and the distance-bas ed scheme. Results demonstrate that when the call-to-mobility ratio (CMR) i s low, the proposed scheme can achieve a significant cost reduction compare d to the movement-based scheme. For example, when the CMR is 0.01, a saving s 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. (C) 2000 Elsevier Science B.V. All rights r eserved.