AN EFFICIENT LOCATION TRACKING SCHEME IN DISTRIBUTED HLR ENVIRONMENT

Abstract

One of the main challenges in personal communication service (PCS) is to locate many mobiles that may move frequently from place to place. Such a system operation is called location tracking. Many network signals flow, and database queries are required to achieve such a task. In addition to the two-level hierarchical strategy in GSM, several strategies have been proposed [4] to improve the efficiency of the location tracking. Pointer forwarding was used to reduce the expensive home location register (HLR) accesses. Previously, the distributed HLR scheme was proposed to prevent HLR from becoming a bottleneck in the signaling network However, the length of a forwarding pointer chain may be lengthened in a distributed HLR environment. Here, I propose a more efficient strategy to overcome this potential problem. This strategy attempts to migrate the locating chains in a distributed HLR system when a mobile issues a registration operation. As a consequence, the length of any forwarding pointer chain does not exceed one in first strategy and does not exceed by k in second strategy. Simulation results indicate that propose strategies significantly decreases the locating cost. Furthermore obsolete entries in local databases visitor location registers can be reclaimed in this strategies.