Leveraging Indirect Signaling for Topology Inference and Fast Broadcast.

The physical (or SINR) model of wireless communication is more intricate than radio networks and still not well understood. If two neighbors of a node are transmitting, the node may be able to decode one of the transmissions, depending on the relative nearness of the transmitters. Thus, even the lack of proper reception carries indirect information. We explore here the power of such indirect signaling to infer the approximate topology of the network. In particular, we obtain a polylogarithmic time algorithm to compute a backbone: a set of nodes of constant density that dominates every ε-neighborhood. A backbone has wide utility for information dissemination, functioning as a sparse spanner. It also leads to fast broadcast, running in O(Diameter) time after a polylogarithmic precomputation, which previously was only known when additional features such as carrier sense, collision detection, geometric coordinates, or power control were available.