A node discovery protocol for ad hoc underwater acoustic networks

A neighbor discovery protocol is proposed for initializing an ad-hoc deployable autonomous underwater system in which the nodes (floating sensors, crawlers, vehicles) have no knowledge of the system topology upon deployment. The goal is to establish multi-hop, minimum-power acoustic communication links over a given coverage area. The protocol uses distributed power control and random access to provide connectivity within a finite power budget and without global synchronization. Physical laws of acoustic propagation are taken into account, namely the distance- and frequency-dependent path loss, as well as large-scale fading which is modeled via log-normal distribution. Simulation results quantify the energy consumption, time to completion, and system reliability in the presence of fading. The key features of the protocol are simplicity of implementation and efficient use of power.