Optimal location management for two-tier PCS networks

Abstract

One of the most important issues in Personal Communication Service (PCS) networks is location management, which keeps track of the Mobile Terminals (MTs) moving from place to place. In this paper, we analytically derive cost functions of location updates and paging for a dynamic movement-based location management scheme for PCS networks with two-tier mobility databases. We prove analytically that there is a unique optimal movement threshold that minimizes the total cost of Home Location Register location updates, Visitor Location Register location updates, and paging, per call arrival. An effective algorithm is proposed to find the optimal movement threshold. Furthermore, we propose a hybrid location management scheme, in which when the call-to-mobility ratio is larger than a threshold, the optimal dynamic movement-based scheme is adopted. Otherwise, the static location update is adopted. The Newton approximation method is adopted to find this threshold. Our study shows that the proposed hybrid scheme outperforms both the dynamic movement-based scheme and the static location update scheme.