Tracking mobile users with uncertain parameters

A method of reducing the wireless cost of tracking mobile users with uncertain parameters is developed in this paper. Such uncertainty arises naturally in wireless networks, since an efficient user tracking is based on a prediction of its future call and mobility parameters. The conventional approach based on dynamic tracking is not reliable in the sense that inaccurate prediction of the user mobility parameters may significantly reduce the tracking efficiency. Unfortunately, such uncertainty is unavoidable for mobile users, especially for bursty mobility pattern. In this study we propose a novel approach, which is efficient yet reliable. The basic idea is to incorporate a distributed scheme with a centralized scheme. The location update process incorporates a topology-independent distance based strategy and a load-sensitive timer. This combination forms a mechanism that bounds from above the total tracking cost. The registration activity is governed by the system, such that it increases at lowly loaded cells and decreases at heavily loaded cells. The expected wireless cost of tracking under the proposed method is significantly reduced, in comparison to the existing methods currently used in cellular networks. Furthermore, as opposed to other tracking methods, the worst case tracking cost is bounded from above and governed by the system. The proposed strategy can be easily implemented, and it does not require a significant computational power from the user.