Geographical routing using partial information for wireless ad hoc networks

In this paper, we present an algorithm for routing in wireless ad hoc networks using information about geographical location of the nodes. We assume each node knows its geographical position and the position of the node to which it wants to send a packet. Initially, the nodes only know their neighbors but over time they discover other nodes in the network. The routing table at a node S is a list h(pi; Si)i where pi is a geographical position and Si is a neighbor of node S. When node S receives a packet for a node D at position pos(D), it finds the pi in its routing table which is closest to pos(D) and forwards the packet to the neighbor Si. We prove the correctness of the algorithm and show that our algorithm naturally aggregates the nodes so that the routing table sizes are of size O( Ln log(n)), where Ln is the mean route discovery path length, and n is the number of nodes. We also present methods for taking positional errors, node failures and mobility into account. We justify the results through simulation.