Hierarchical routing over dynamic wireless networks

Abstract

In dynamic networks the topology evolves and routes are maintained by frequent updates, consuming throughput available for data transmission. We ask whether there exist low-overhead schemes for these networks, that produce routes that are within a small constant factor (stretch) of the optimal route-length. This is studied by using the underlying geometric properties of the connectivity graph in wireless networks. For a class of models for wireless network that fulfill some mild conditions on the connectivity and on mobility over the time of interest, we can design distributed routing algorithm that maintain the routes over a changing topology. This scheme needs only node identities and integrates location service along with routing, therefore accounting for the complete overhead. We analyze the worst-case (conservative) overhead and route-quality (stretch) performance of this algorithm for the aforementioned class of models. Our algorithm allows constant stretch routing with a network wide control traffic overhead of O ( n log 2 n ) bits per mobility time step (time-scale of topology change) translating to O (log 2 n ) overhead per node (with high probability for wireless networks with such mobility model). We can reduce the maximum overhead per node by using a load-balancing technique at the cost of a slightly higher average overhead. Numerics show that these bounds are quite conservative.