Simulation of the effect of site shielding on digital communication systems: from diffraction to global link performance

The protection of an earth station from an interfering terrestrial signal by a natural or man-made obstacle is known as site shielding. Three theories are commonly used to describe the interaction of an incident wave with obstacles: the Fresnel surface integral method, the parabolic equation method and the uniform theory of diffraction (UTD). Although those various techniques have successfully been applied to tackle problems like diffraction by one or several block-shaped obstacles, diffraction under nonuniform illumination, etc., the present models concerning site shielding applications usually consider only the interfering signal and fail to deal with the interaction between the interfering and the wanted field. Furthermore, the interfering signal is merely represented as an unmodulated carrier. A very general and easy to implement method based on the use of four transfer functions and of a communication link simulator is underlined that allows to overcome the above-mentioned shortcomings