An eigenpath underwater acoustic communication channel model

Ocean exploration can require high data rate transmission over an underwater acoustic channel. The properties of underwater acoustic channels are thus very important in the design of high data rate acoustic telemetry systems. The authors review the essential properties of such channels. Based on some experimental results and analytical considerations they point out the limitations of the Rayleigh fading model commonly used in modeling underwater acoustic channels. This model has been adapted from microwave and radio communications in which received signals arrive along scattered paths. In an underwater acoustic channel there can be several distinct paths (eigenpaths) over which a signal can propagate from transmitter to receiver (eigenpath signals). Each eigenpath signal contains a dominant, stable component and many smaller, randomly scattered components (sub-eigenpath components). The envelope of the eigenpath signal can therefore be described using a Rice fading model. Based on the above the authors develop a novel channel model in which each eigenpath signal is described using a certain signal-to-multipath ratio, propagation time delay and Doppler shift. They propose a structure for a simulator of such a channel, to be used in conjunction with different transmission schemes.