BRUMA: Beacon-less geographic routing for multicast applications

We study the problem of geographic multicast routing in a wireless sensor network. In particular, we are interested in geographic routing solutions with a very limited control overhead and overall bandwidth consumption. Existing geographic multicast routing protocols require nodes to periodically exchange beacon messages to gather information about the position of their neighbors. These beacons represent a waste of resources, specially in areas of the network with no active communications. Beacons also induce significant problems in real deployments such as interferences and collisions that cause inconsistencies in neighboring tables. In this paper we propose a new beacon-less geographic multicast routing protocol called BRUMA. Unlike previous solutions, BRUMA uses the propagation of data packets to opportunistically select next hops among those that are reachable from the sending node. This allows the protocol to overcome most of the issues of beacon-based solutions in real deployments. Our simulations show that BRUMA achieves a higher packet delivery ratio and a lower overall bandwidth consumption than GMR, which is the protocol performing best among existing geographic multicast solutions.