Propagation over Parabolic Terrain: Asymptotics and Comparison to Data

Analysis of radio propagation over varying, cluttercovered terrain was carried out aiming at prediction of power received by a terminal immersed in clutter, with the transmitter placed above clutter. The need for such prediction arises, for example, in planning and assessing coverage and interference in radio communications. Following a general formulation of the problem, particular solutions were found when the terrain has constant curvature. Asymptotic evaluation yielded compact expressions both for parabolic valleys and ridges. In both cases, ray-optical term dominated for short ranges, while a single mode dominated at large ranges. Strong focusing was found to occur in valleys, while ridges produced strong blockage beyond the "horizon". In comparison to measured power across a valley, mean errors of less than 1 dB were found, a marked improvement over standard terrainunaware models that produce a mean error of 30 dB.