Seaweb Acoustic Communication and Navigation Networks

Seaweb networks interconnect fixed and mobile nodes distributed across a wide area in the undersea environment. Acoustic communications between neighboring DSPequipped telesonar modems is the basis for the physical layer. Node-to-node ranging is a byproduct of telesonar signaling, permitting localization of sensor nodes and navigation of mobile nodes such as submarines and autonomous vehicles. The unusual characteristics of the physical-layer medium constrain the design of the link and network layers. Seaweb datapacket communications are achieved through the ancillary use of compact channel-tolerant utility packets. Measuring the available acoustic channel permits link optimization by adapting the data-packet signal parameters to the prevailing channel attributes. Link-layer methods including forward error correction, handshaking, and automatic repeat request provide reliability. Network-layer mechanisms such as distributed routing tables, neighborsense multiple access, packet serialization, and return receipts enhance quality of service. This paper reviews the concept of operations for undersea networks with illustrative examples of actual Seaweb deployments.