The CLU mobility management scheme for digital cellular systems

A digital cellular system is divided into location areas and the movement of mobile users is tracked only when they cross from one location area to another. The system pages over an entire location area when it needs to find a mobile to terminate an incoming call. Most cellular systems use this basic mobility management scheme to track mobile locations, and attempt to optimize the size of the location areas versus the number of pages needed to locate a mobile. In this paper, we present a new mobility management scheme called cell location update (CLU) which informs each site of mobiles present in its coverage area. Paging to locate a mobile is done over a much smaller set of sites rather than an entire location area. This new scheme significantly reduces paging related traffic: up to 70% reduction in the case of iDEN, and up to 50% in the case of GSM. The number of corresponding location area updates is also reduced by about 40%.