Seaweb Acoustic Communication and Navigation Networks

Abstract

Seaweb networks interconnect fixed and mobile nodes distributed across a wide area in the undersea environment. Acoustic communications between neighboring DSP-equipped telesonar modems is the basis for the physical layer. Node-to-node ranging is a by-product 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 data-packet 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, neighbor-sense 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.