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 crossed n cell boundaries, and then, a time interval T elapsed. We also examine the inverse scheme, where an update is performed after the n boundary crossings occur subsequent to the time interval T . We evaluate our scheme by applying it to various mobility models, such as exponential cell-residence times with a constant mobility pattern, exponential cell-residence times with a gamma-distributed mobility pattern , hyperexponential cell-residence times, and cell-residence times with a small coefficient of variation. 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.