Scattering by trees in microcellular environments

Accurate, site-specific, wideband propagation prediction models are becoming increasingly necessary in planning future mobile radio systems, especially in the context of provision of broadband multimedia services to the handset. Access to such models is especially important for planning urban microcells, which feature high density of users and levels of interference. Site-specific ray-optical models seem to be the most appropriate for this case and are widely used. The ray-optical models are not able to calculate exactly the received field due to the complexity of the real environment and the electromagnetic scattering processes in it. Most such models restrict their predictions to only a few well-studied propagation mechanisms, such as specular reflection and diffraction, and neglect most other mechanisms such as scattering, transmission, etc. A number of measurements performed as part of the BT Virtual Universities Research Initiative (BT VURI) on Mobility was intended to identify the major propagation mechanisms that have to be included in the improved microcellular prediction models. Some of the results of this effort have already been reported by Mughal, Street and Constantinou, (see VTC, Boston, USA, 2000) in where the significance of non-specular reflection from, as well as transmission through, buildings was demonstrated. We address another identified propagation mechanism as significant, namely scattering by trees.