Analysis of the Impact of Flow on the Underwater Acoustic Channel

Abstract

Reliable and power efficient underwater communication systems that can adapt to the medium’s changing nature can be designed with knowledge of the physical underwater environment. This thesis discusses a stochastic model for an underwater acoustic channel that takes into consideration the effects of mean flow and turbulence on the acoustic signal in environments subject to some of the highest tides in the world. The model, relying fundamentally on ray tracing, generates an ensemble of time-varying channel characteristics by capturing the effect of known environmental changes, including the effective perturbation of the sound speed in the medium through mean and turbulent flow. The model is used to extract the channel characteristics such as channel gain, delay spread, Doppler spread, and propagation delay. By validating simulation results with real measurements taken in the Bay of Fundy, it is demonstrated that the mean flow has significant impact on various channel characteristics.