Enhancing broadcast operations in ad hoc networks with two-hop connected dominating sets

We introduce the three-hop horizon pruning (THP) algorithm to make broadcast operations more efficient in ad hoc networks using contention-based MAC protocols. THP builds a two-hop connected dominating set (TCDS) of the network, which is a set of nodes such that every node in the network is within two hops from some node in the dominating set. Efficiency of broadcast operations is attained by implementing forwarding schemes that take advantage of a TCDS. More specifically, every node provides its one-hop neighbors with a list specifying one or more tuples, each with the identifier of a one-hop neighbor and a bit indicating if that neighbor dominates any two-hop neighbor. To forward a broadcast packet, a node tries to obtain the smallest subset of forwarders, which are one-hop neighbors that use some of the node's two-hop neighbors to reach any node that is three hops away. After such a selection of forwarders, the node broadcasts its packet with a header specifying the list of forwarders, and each forwarder in turn repeats the process.