Range and depth dependency of coherent underwater acoustic communications in KauaiEx

Data collected from the Kauai experiment (KauaiEx) shows that the fluctuations of the ocean environment can cause significant variations of the acoustic signals propagating in the shallow water regions. The power level of the arrivals that do not interact with the sea surface is mainly affected by the variability of the ocean water column. The power level of the arrivals that interact with the sea surface, especially those interacting with the sea surface multiple times, is mainly affected by the sea surface condition. Therefore, the signal to interference plus noise ratio (SINR) varies in a way related to the fluctuations of the physical ocean parameters, mainly the water temperature profile and the sea surface condition. Such SINR variations might be significant for certain source/receiver geometries. The ocean variability has impact on SINR and, therefore, on the performance of the coherent underwater acoustic communications (UAC) receiver, as demonstrated by the collected binary phase shift keying (BPSK) signals from the experiment.