Area Based Beaconless Reliable Broadcasting in Sensor Networks

We consider the broadcasting problem in sensor networks where the nodes have no prior knowledge of their neighbourhood. We describe several Area-based Beaconless Broadcasting Algorithms (ABBAs). In 2D, on receiving the packet (together with geographic coordinates of the sender), each node calculates the ratio P of its perimeter, along the circle of transmission radius, that is not covered by this and previous transmissions of the same packet. The node then sets or updates its timeout to be inversely proportional to P. If the perimeter becomes fully covered, the node cancels retransmissions. Otherwise, it retransmits at the end of the timeout interval. The protocol is reliable, that is, all nodes, connected to the source, are guaranteed to receive the packet, assuming an ideal MAC layer. We also describe three 3D-ABBAs, one of them being reliable. These three protocols are based on covering three projections, covering particular points on intersection circles and covering intersection points of three spheres. Our protocols are the first reliable broadcasting protocols, other than blind flooding.