Wireless Signal Attenuation by Vegetation: Relationship Between Tree Characteristics and Signal Attenuation

Abstract

Vegetation is a significant factor that affects the Quality of Service of radio waves. Several measurement campaigns have been conducted to predict the effect of trees on a radio wave at the micro and millimetre wavelengths. The experiments show that depth of vegetation is a major factor that contribute to signal attenuation. Furthermore, different components of the vegetation cause different behaviours of the radio wave. The empirical models did not put into to consideration the characteristics of the trees in the vegetation. The analytical approaches using wave theory have considered the vegetation characteristics, density and the geometry. This paper focuses on using existing models to characterise a vegetation based on measured parameters of a tree stand with a view to estimating the density of the foliage within a vegetation accurately. The foliage density will be used as the vegetation parameter in the wave theory model. Simulation of the signal attenuation will be conducted based on the density of the vegetation that will be estimated. The tree species selected for simulation are Pinus, Ash and Silver Birch tree species.