Fading Distribution Model for the Maritime Radio Channel

The envelope fading distribution is derived for the round earth loss maritime radio channel. The propagation environment considered consists of a line of sight (LOS), and from the sea a specular reflection and a diffuse component. The phase difference between LOS and specular component is given by the relative path lengths and the change of phase in the sea reflection. The relative path length changes locally with the vertical movement of a ship-mounted antenna. The height variations are modeled as Normal distributed, resulting in a Normal distributed phase difference. This is an extension of the two-wave diffuse power (TWDP) model in which the phase difference between LOS and specular reflection is modeled as uniformly distributed.