Adaptive location management scheme for global personal communications

A major issue for achieving seamless universal personal communications is efficient location tracking of a multitude of mobile terminals. The approach in which each mobile registers in relatively small location areas may not be adequate for global personal communications because a very large number of mobile terminals with a broad range of terminal mobilities may generate excessive location updating traffic. As an alternative, the authors present an efficient multilayer mobility management scheme that is especially suitable for hierarchical cellular structures. The scheme accounts for past as well as present terminal mobilities and dynamically changes the hierarchical level of the location area to which a mobile terminal registers. In a system that contains both a terrestrial segment and a satellite segment, highly mobile terminals such as an aircraft will tend to register at the highest level where location areas are formed by spotbeams. Low mobility terminals such as pedestrians will tend to register at the lowest level where location areas are formed by microcells or clusters of microcells. An additional feature of the scheme is that the required signalling traffic for location updating is distributed evenly to all stations at each level of the system. An analytical model is developed to determine the required location updating supervisory traffic of the proposed scheme. Example performance characteristics are presented. The proposed scheme can track large numbers of terminals with a broad range of mobility