Propagation over Clutter: Physical Stochastic Model.

Propagation of radio signals from a base above clutter, such as buildings and trees, to a mobile immersed in clutter is treated theoretically by accounting for random diffuse scattering at the mobile. Small-scale fading and distance-dependent loss are treated in a unified way, as opposed to the heuristic methodologies, which formulate them as separate factors. Closed form expressions are derived for path gain and for angular spectrum at the base in both urban and heavily foliated environments. The resulting predictions are in close agreement with widely accepted models and empirical results. The angular spectrum at the base in urban environments is found to be Lorentzian of width close to that reported for measurements in Aarhus. In foliated environments, vegetation is represented as statistically homogeneous diffuse scattering medium, resulting in a Gaussian-shaped angular spectrum at the base.