Location update optimization in personal communication systems

Mobility tracking is concerned with finding a mobile subscriber (MS) within the area serviced by the wireless network. The two basic operations for tracking an MS, location updating and paging, constitute additional load on the wireless network. The total cost of updating and paging can be minimized by optimally dividing the service area into location registration (LR) areas. There are various factors affecting this cost, including the mobility and call patterns of the individual MS, the shape, size and orientation of the LR area, and the method of searching for the MS within the LR area. Based on various mobility patterns of users and network architecture, the design of the LR area is formulated as a combinatorial optimization problem. The objective is to minimize the location update cost subject to a constraint on the size of the LR area.