A hierarchical multiresolution registration structure for mobility tracking

The problem of locating mobile users through location registration and paging is considered. A new class of registration schemes are proposed. In these schemes overlapping registration areas of various sizes are allowed. Depending on the degree of overlap, the performance of the registration scheme may range from that of the static strategy based on disjoint registration areas (used in IS-41 and GSM), to that of the dynamic distance based location update strategies. The latter achieve significantly better trade-offs between paging and registration rates than the static strategy. The availability of various registration area sizes allow the mobile to pick the one that fits better to its call/mobility pattern. An algorithm is obtained which given an heterogenous mobile population with a variety of call/mobility patterns and a registration scheme, determines an allocation of mobiles to registration areas such that the resulting aggregate registration and paging rates are below certain target values, whenever the target values are achievable. The proposed class of registration schemes are amenable to a static implementation with minimal processing requirements at the mobile terminal of the same levels as in the mobility management schemes in IS-4 and GSM, while they may achieve performance equivalent to dynamic location update strategies.