Lateral propagation effects over irregular terrain

This paper presents a coverage prediction algorithm for wireless systems deployed over hilly and mountainous areas. The algorithm is based on an asymptotic diffraction approximation for field predictions over irregular terrain. The field predictions are based on a quasi-3D approach that takes into account the effect of lateral contributions. The dominant path profile is computed according to a modified Fresnel v parameter that incorporates the effect of surface curvature. The algorithm can be implemented on any asymptotic diffraction approximation that models terrain irregularities by means of canonical shapes. For the purpose of this investigation the multiple Uniform Theory of Diffraction (Slope-UTD) is used and it is shown that in many scenarios dominant propagation paths may arise from lateral instead of great circle (vertical plane) propagation. This justifies the fact that in some cases, the assumption of vertical plane propagation underestimates field values in real scenarios.