Variability in link performance of an underwater acoustic network

Performance prediction of underwater acoustic network protocols is difficult due to the variability of performance of individual links in the network. Link performance is usually a complex function of several environmental and modem parameters. To understand the network and link performance variability better, we deployed a 5-node network spanning an area of about 1 km² in Singapore waters over the period of a few days. We also deployed several environmental sensors to measure water currents, sea surface motion, wind speed, rain, sound speed profile, and ambient noise. Acoustic ranging between the network nodes allowed us to accurately localize the nodes underwater. By transmitting probe signals, we were able to accurately measure acoustic propagation between nodes, and understand its impact on link performance. We present preliminary results from this experiment to show how link performance varied with location, range and environmental changes.