Issue No. 11 - November (2007 vol. 6)
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/TMC.2007.1014
The stochastic model assumed to govern the mobility of nodes in a mobile ad hoc network have been shown to significantly affect the network’s coverage, maximum throughput, and achievable throughputdelay tradeoffs. In this paper, we compare several mobility models, including the random walk, random waypoint and Manhattan models, on the basis of the number of states visited in a fixed time, the time to visit every state in a region, and the effect of the number of wandering nodes on the time to first entrance to a set of states. These metrics for a mobility model are useful for assessing the achievable event detection rates in surveillance applications where wireless-sensor-equipped vehicles are used to detect events of interest in a city. We also consider mobility models based on Correlated Random Walks, which can account for time dependency, geographical restrictions, and nonzero drift. We demonstrate that these models are analytically tractable by using a matrix-analytic approach to derive new, closedform results in both the time- and transform-domains for the probability that a node is at any location at any time for both semi-infinite and finite one-dimensional lattices. We also derive first entrance time distributions for these walks. We find that a correlated random walk (i) covers more ground in a given amount of time and takes a smaller amount of time to cover an area completely than a random walk with the same average transition rate; (ii) has a smaller first entrance time to small sets of states than the random waypoint and random walk models and (iii) leads to a uniform distribution of nodes (except at the boundaries) in steady state.
MANET, mobility models, correlated random walk, random walk, random waypoint model
T. Falck, S. Bandyopadhyay and E. J. Coyle, "Stochastic Properties of Mobility Models in Mobile Ad Hoc Networks," in IEEE Transactions on Mobile Computing, vol. 6, no. , pp. 1218-1229, 2007.