A Markov-based Diurnal Mobility Model for 3G Cellular Networks

Abstract

User mobility is an important aspect for handoff planning in cellular networks because handoff depends on network topology (configuration of cells) and user mobility pattern. Mobility pattern largely depends on the user’s behavior, geographical area, location, dwell time, direction and speed. While case studies are rare in public domain, most analytical and simulation studies adopt circular and hexagonal cell configuration. A pure random walk mobility model using hexagonal cells assumes that a user can move in all six directions from its current cell to its neighboring cells with equal probability (1/6) while that using circular cells assumes uniform distribution over some predefined fixed directions. However, such assumptions are not applicable in practical cases where users know their destination locations before the move. Such move is not purely random; rather it is somewhat direction-based and depends on present location and the destination of the user. For instance, a user often returns to the source when mobility is diurnal. In this paper we have studied direction-based diurnal mobility model of a user. We have formulated a Markov model for such movement and have given a theoretical upper bound of cell boundary crossings (expected number of handoffs) by the user. We also simulate the mobility environment and observe that a majority of complex and simple handoff comes from a small number of cells of the network.