Shallow Water Acoustic Channel Modeling Based on Analytical Second Order Statistics for Moving Transmitter/Receiver

Underwater acoustic channels are among the most challenging communication media. Time-varying multipath fading, long delay spread, significant Doppler spread, and frequency-dependent path loss are the main aspects of such channels. In this paper we present a statistical shallow water channel model for moving transmitter/receiver based on analytical second order statistics. To do so, we first propose a channel impulse response (CIR) model that captures most of the physical properties of shallow waters. Then we find the probability density function (PDF) of the angle of arrival (AoA) for paths with different number of surface and bottom reflections. To find closed form expressions for the second order statistics of the CIR, we approximate the PDFs of AoA with half-circular Rice PDF: a novel PDF introduced in this work. By mathematical tractability of this new PDF, analytical statistics including autocorrelation function, scattering function, and time-frequency correlation function are derived. The results are compared with experimental findings for verification.