Underwater acoustic network performance: Results from the UAN11 sea trial

An underwater acoustic network (UAN) represents a communication infrastructure that can offer the necessary flexibility for continuous monitoring and surveillance of critical infrastructures located by the sea. Given the current limitation of acoustic-based communication methods, a robust implementation of UANs is still an open research field. The FP7 UAN project moved along these lines, and it was one of the first cases of successful deployment of a mobile underwater sensor network integrated within a wide-area network, which included above water and underwater sensors. This contribution gives details on the UAN network structure and equipment. It reports statistics on the performance of the system as collected during the project final sea trial, which was held in Trondheim, Norway, in May 2011. The UAN network was in operation for five continuous days and was composed of up to four fixed nodes, two autonomous underwater vehicles and one mobile node mounted on the supporting research vessel. Results from the experimentation at sea are reported in terms of channel impulse response and signal to noise plus interference ratio as measured by the acoustic modems during the sea tests. The performance of the upper network levels are measured in terms of round trip time and probability of packet loss. Finally, the experimental results have been compared with those obtained in simulation using the BELLHOP acoustic code, fed with the environmental data gathered during the sea trial.