A Dynamic Location Tracking Strategy for PCS Using Hierarchical Location Databases

Abstract

In this paper, we propose a dynamic location tracking strategy for the hierarchical location database architecture in personal communication service systems (PCS). In our strategy, a user’s current location is stored at a specific location database, called the local anchor (LA). We focus on studying the problem how to decide the best position for the LA to get a great benefit in location registration. The LA periodically collects the user’s mobility and calling patterns and dynamically changes its position according to his/her behavior after a period of time. When a user has a small call-to-mobility ratio (CMR), our strategy efficiently reduces registration costs. Besides, we use caching bypass pointers for call delivery procedures but avoid cache miss which happens in the caching strategy. Thus our strategy has the same performance as the caching strategy in reducing call delivery costs when the CMR is large, but performs much better than the caching strategy when the CMR is small. Our simulation result shows that our strategy produces 30% performance improvement than the basic strategy and 20% performance improvement than the caching strategy.