A geometry-based channel model for shallow underwater acoustic channels under rough surface and bottom scattering conditions

This paper develops a stochastic geometry-based channel model for wideband single-input single-output (SISO) shallow underwater acoustic (UWA) channels under the assumption that the ocean surface and bottom are rough. Starting from a geometrical model, we derive a reference model assuming that the scatterers are randomly distributed on the surface and the bottom of the water. The probability density functions (PDFs) of the angle-of-departure (AOD) and the angle-of-arrival (AOA) of the reference model are analyzed. Furthermore, the two-dimensional (2D) time-frequency correlation function (T-FCF) of the reference model is studied. From the reference model, we then derive the corresponding simulation model by applying the generalized concept of deterministic channel modelling. For the parametrization of the UWA channel simulator, we propose a new method which is further on called the method of equally spaced scatterers (MESS). The performance of the MESS is compared with that of the L_p-norm method (LPNM). It is shown that our design concept results in an excellent match between the T-FCF of the reference model and that of the simulation model. It is also shown that both the MESS and the LPNM have a similar performance, whereby the MESS provides a closed-form solution, while the LPNM does not.