A Networking Protocol for Underwater Acoustic Networks

Abstract : There exists an increasing demand for reliable, high capacity Underwater Acoustic Networks (UANs), as evidenced by the large volume of research invested over the last decade in overcoming the difficulties inherent with propagation of information bearing signals through shallow water regions. Application interests include oceanographic information gathering, environmental monitoring, and coastal defense (anti-submarine and mine/counter-mine warfare). Two specific examples of the recent efforts to develop and field UANs in shallow water regions are the Deployable Autonomous Distributed System funded by the Office of Naval Research (ONR) and the Autonomous Oceanographic Sampling Network sponsored by ONR and the National Science Foundation. The Deployable Autonomous Distributed System (DADS), envisioned to provide undersea surveillance in littoral waters [Rice 2()()()1, is an underwater array of fixed sensor plattorms, interconnected by acoustic modems. The network connects the remote sensor plattorms to a coim%and center through a portal that relays data received from the acoustic network to the distant coim%and facility across satellite links. Acoustic data is propagated through the network over multi-hop coim%unications paths. The individual hops are configured as half duplex code division multiple access links between discrete modem pairs. Messages are relayed between paired platton%s to minimize the transmit power requirements and reduce the impact of tempon%l, spatial, and frequency spreading of the signal as it propagates through the littoral channel.