Density of Multipoint Relays in Dense Wireless Multi-hop Networks

Multipoint relays (MPRs) support efficient flooding of topology control messages in OLSR. Since the shortest path is constructed as a sequence of MPRs, MPRs are the nodes of the backbone network. In this paper, we explore dense wireless multi-hop networks, and analyze the density of MPRs in such networks. We explain three properties to increase the number of MPRs: (1) each MPR is far from its selector, (2) MPRs of a node are close to each other, and (3) even if two nodes are close to each other, they tend to select different MPRs, in dense networks. These properties make the density of MPRs high. Concerning the third property, we explain a non-distributed MPR selection algorithm, to show the chance to select the same MPRs with neighbors. Finally, we measure the MPR ratio and the routing overhead of topology control messages, in dense wireless multi-hop networks by simulation.