Design and analysis of location management for 3G cellular networks

Location management is a key issue in personal communication service networks to guarantee the mobile terminals to continuously receive services when moving from one place to another. We study two location management schemes, a dynamic movement-based scheme (DYNAMIC-3G) and a static scheme (STATIC-3G), for 3G cellular networks where home location registers, gateway location registers (GLRs), and visitor location registers form a three-level hierarchical mobility database structure. For both schemes, the cost functions are formulated analytically. We prove that there is an optimal movement threshold that minimizes the total cost function of DYNAMIC-3G and propose a binary search algorithm to find the optimal threshold. Furthermore, we present performance evaluation and comparison of the proposed schemes with the previous schemes in 2G cellular networks where the GLR is not present. Our studies validate the optimality of the DYNAMIC-3G scheme and show that the proposed schemes outperform the previous schemes, especially when the remote-local-cost ratio is high. The comparison results between DYNAMIC-3G and STATIC-3G indicate that DYNAMIC-3G should be adopted when the mobility rate is low, and STATIC-3G should be adopted otherwise. Furthermore, DYNAMIC-3G tends to perform better than STATIC-3G when the paging cost is high or the number of cells in a location area is large.