Disjoint multipath source routing in ad hoc networks: transport capacity

While much of the effort on routing in ad hoc wireless networks is focused on source routing and flooding, in this work we explore the possibility of applying packet switching concept to an ad hoc wireless environment. It is well known that packet switching is a robust and efficient technique for data that can tolerate some delay. Similar to the traditional packet switching technique, we propose a disjoint multipath source routing (DMPSR) technique which allows packets originating from the same source to be statistically multiplexed onto multiple disjoint routes. Each route can relay packets from multiple sources. In this paper, we analyze the transport capacity of this scheme and compare the result to that obtained in P. Gupta et al. (2000) and O.K. Tonguz et al. (2003), which consider single path source routing. Given a network of size A with N mobile nodes, each capable of transmitting at R bps, our results show that the maximum transport capacity of this scheme converges to R√(AN) when load balancing is employed (i.e., number of routes being relayed through any given node is the same for all the nodes). If, however, no load balancing is used, then the transport capacity of DMPSR will be greater than that of the traditional source routing when the spatial density of the network is below some critical threshold. Beyond the critical threshold, however, transport capacity is significantly less than the one obtained in O.K. Tonguz et al. ( 2003) and P. Gupta et al. (2000) since a mobile node has to spend more time relaying messages for other sources.