Location management based on distance and direction for PCS networks

This paper proposes a distance-and-direction-based location management scheme with a nonisotropic mobility model to capture the directional movement of an MT, which remarkably reduces the total cost at the cost of a slight increase in the location update cost. In this scheme, whenever a distance threshold or a direction threshold is exceeded, a location update is performed. When a call arrives, the network pages the called MT within the paging area defined by the distance threshold and direction threshold. In addition, an online distance-and-direction calculation method, and an interactive distance-and-direction optimization algorithm are developed to dynamically adjust the paging area. We analyze this scheme using a Markov chain for both one-dimensional (1-D) case and two-dimensional (2-D) case. Specifically, a good state coalition method is proposed to reduce sharply the computational complexity of the 2-D cost evaluation. Numerical results suggest that substantial cost saving can be obtained by fully utilizing the mobility direction information. Therefore, the proposed scheme outperforms the distance-based scheme.