Statistical Modeling and Performance Analysis of Cooperative Communication in Frequency-Selective Underwater Acoustic Channel Using Vector Sensor

In this work, an angle of arrival (AoA) based statistical model for the path gain in an underwater (UW) channel is proposed considering the randomness of the line of sight and specular paths. The channel is assumed to be wide sense stationary (WSS), time-variant, and frequency-selective. The proposed model is used to obtain a novel characterization of a multi-hop multi-branch (MHMB) cooperative framework for a frequency-selective UW channel. In this general system architecture, multipath exists between any pair of consecutive hops. It is observed that when AoA is Gaussian distributed, then the path gain has a log-normal distribution. We use the Gauss Quadrature Rule (GQR) representation of the Moment Generating Function (MGF) of a log-normal distribution to derive the expressions for average bit error rate (BER) and ergodic capacity (EC) for a MHMB cooperative framework. Results for i) Pressure sensor (PS) as receiver and ii) Vector sensor (VS) as receiver for the dual-hop cooperative model are obtained and compared. Excellent matching between results acquired from Monte Carlo (MC) simulation and numerical integration (NI) expressions validate the accuracy of the derived expressions. Expectedly VS based communication systems perform better.