On Demand Routing in Large Ad Hoc Wireless Networks with Passive Clustering

Abstract – This paper presents on-demand routing scalability improvements achieved using a “passive ” clustering. Any on demand routing typically requires some form of flooding. Clustering can dramatically reduce transmission overhead during flooding. In fact, by using clustering, we restrict the set of forwarding nodes during flood search and thus reduce the energy cost and traffic overhead of routing in dynamic traffic and topology environments. However existing “active ” clustering mechanisms require periodic refresh of neighborhood information and tend to introduce quite a large amount of communication maintenance overhead. In this paper, we introduce a passive clustering scheme which is mostly supported/maintained by user data packets instead of explicit control packets. The passive scheme is consistent with the on-demand routing philosophy. Simulation results show significant performance improvements when passive clustering is used. 1