Assessment of underwater acoustic channel during payload data exchange with hydro-acoustic modems of the S2C series

Characteristics of an underwater acoustic channel, which hydro-acoustic modems of the S2C technology can measure and provide to upper layer protocols, were used for evaluation of several important communication metrics and so for evaluation of the modem performance under the actual channel conditions. Particularly, these channel characteristics were used for assessment of the delivery success related to the measured signal integrity, the signal-to-interference ratio, and the variance of excess propagation delays of the multipath arrivals. Paper presents experimental results on the use of Instant Messages for the characterisation of the underwater acoustic channel during data exchange between multiple nodes of an underwater acoustic network. Experiments were carried out in conditions of reverberant underwater acoustic channels using the modems, type Evologics S2CR18/34, during the NATO CommsNet13 sea campaign, organized by the Centre for Maritime Research and Experimentation (CMRE) and conducted in September 2013 off the coast of the Palmaria Island in the Mediterranean Sea.