Virtual Mobile Nodes for Mobile Ad Hoc Networks

Report, 2004

One of the most significant challenges introduced by mobile networks is the difficulty in coping with the unpredictable movement of mobile nodes. If, instead, the mobile nodes could be programmed to travel through the world in a predictable and useful manner, the task of designing algorithms for mobile networks would be significantly simplified. Alas, users of mobile devices in the real world are not amenable to following instructions as to where their devices may travel. While real mobile nodes may be disinclined to move as desired, we propose executing algorithms on virtual mobile nodes that move in a predetermined, predictable, manner through the real world. In this paper, we define the Virtual Mobile Node Abstraction, and present selected algorithms that take advantage of virtual mobile nodes to simply and efficiently perform complicated tasks in highly dynamic, unpredictable mobile ad hoc networks. We then present the Mobile Point Emulator, a new algorithm that implements robust virtual mobile nodes. This algorithm replicates the virtual node at a constantly changing set of real nodes, choosing new replicas as the real nodes move in and out of the path of the virtual node. We claim that the Mobile Point algorithm correctly implements a virtual mobile node, and that it is robust as long as the virtual node travels through well-populated areas of the network.