Hybrid Location-Update Scheme for Mobile Networks

In this paper, we propose a hybrid location-update scheme, which combines the time- and movement-based location-update approaches. In the proposed scheme, a mobile user updates its location after the following two events have occurred: First, the mobile crossedncell boundaries, and then, a time intervalTelapsed. We also examine the inverse scheme, where an update is performed after thenboundary crossings occur subsequent to the time intervalT. We evaluate our scheme by applying it to various mobility models, such asexponentialcell-residencetimeswithaconstantmobilitypattern,exponentialcell-residencetimeswithagamma-distributedmobilitypattern,hyperexponentialcell-residencetimes, andcell-residencetimeswithasmallcoefficientofvariation. From our numerical analysis and simulation results, we learn that the movement-based-only method (i.e.,T= 0) performs well when the coefficient of variation of the cell-residence time is relatively small. However, when the coefficient of variation is large, the proposed hybrid scheme (i.e., T> 0,n > 0) outperforms each of the two approaches, namely, the time- and movement-based location-update schemes, when these schemes are individually applied.