From Location to Position Management: User Tracking for Location-based Services

This paper compares traditional location management, which focuses on tracking mobile subscribers in the topology of a cellular network, with position management, which we define to be a set of functions for tracking mobile targets in terms of geographic positions as needed for LBSs. As the air interface is the most limited resource in a mobile network, location management has been optimized with regard to signaling overhead caused by updating location data (and paging) between the terminal and the network. Position management is exposed to the same limitations, but, on the other hand, imposes much stronger requirements with regard to accuracy of position data as well as flexibility of tracking. This paper presents an architecture for tailoring the tracking process according to the special LBS requirements on the one hand and limiting the resulting update traffic at the air interface on the other. The architecture is shared between mobile terminals and an application server, for which we present first details of our implementation.