Study on a ring search scheme with a controllable count of location area layers

In mobile computing environment, how to locate a mobile effectively and how to reduce the cost of the system tracking the mobile, i.e. location management, is a challenging frontier. The basic location management scheme of personal communications services (PCSs) networks, such as GSM and IS-41, requires that location updating be initiated immediately whenever a mobile crosses the boundaries of location areas. Obviously, this scheme wastes the system´s resources substantially since a lot of location updating may be unnecessary. Based on layered location areas and ring search scheme and a controllable parameter, a new location management scheme, in which almost no location updating is needed when a mobile crosses boundaries of location areas, is proposed to reduce the cost of location management. Moreover, a probability formula of a mobile residing in each location area layer between two successive call arrivals is proposed by means of constructing an Markov chain and using its equilibrium equation. Moreover, some numeric values calculated by Microsoft Visual C++ programs are presented and analyzed.