Geographic Messaging in Wireless Ad Hoc Networks

This paper presents a network layer mechanism for the efficient dissemination of Global Positioning System (GPS) based node position in ad hoc networks, and shows its application to problems involving geographic awareness. In particular, we describe how, based on a “position database” maintained through the dissemination mechanism, a node of the network can direct messages to all the nodes currently present in a precise geographic area. The effectiveness and accuracy of the dissemination mechanism is demonstrated through the use of simulations. We show that for ad hoc networks with up to 60 nodes, the position database correctly determines which nodes are actually in the expected geographic area the 97% of the time.