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. Closed form expressions are derived for path gain as well as for angular spectrum at the base. The resulting predictions are in close agreement with widely accepted models and empirical results. The angular spectrum at the base is found to be Lorentzian of width close to that reported for urban measurements in Aarhus. Small-scale fading and distance-depedent loss are treated in a unified way, as opposed to the heuristic methodologies, which formulate them as separate factors.