Adaptive directional‐aware location update strategy

Abstract

AbstractIn this paper, a new tracking strategy, the directivity‐aware location updating scheme was developed to better utilize the distinct characteristics of individual users on travelling directions. In this new adaptive scheme, an optimal distance‐based update threshold is selected according to the call‐to‐mobility ratio and a transitional directivity index, introduced to give indications of the mobile's travelling patterns. It is found that as far as mobility characteristics are concerned, the actual transitional direction of roaming mobiles plays a significant role in selecting the optimal threshold in addition to the usual perception about mobility rate. Its advantage becomes even more visible when an optimal threshold is not theoretically obtainable due to certain restrictions imposed by the network during times of high system loadings. Simulation results show that the additional information made available about roaming mobile's transitional directivity is critical to ensure that the best available sub‐optimal threshold is realizable. Other advances in this paper include the simplification of existing Markovian movement model. With the improved model presentation, the number of states necessary to simulate such memoryless movements is reduced. Consequently, the computational complexity involved is also lessened. Copyright © 2004 John Wiley & Sons, Ltd.