Signal propagation through vegetation: consideration for future broadband communication systems

This paper describes the analysis conducted on an extensive set of measurements into signal propagation through vegetation using a wideband channel sounder. The measurements were conducted at thirteen sites and investigated seven different species of trees and four different measurement geometries for in- and out-of-leaf conditions. The purpose of the measurement campaign was to identify the channel characteristics that can influence the design of future broadband communication systems. In order to do this some form of characterisation of the frequency selectiveness and intersymbol interference of the channel must be conducted alongside the flat fading characterisation. This investigation found little correlation between wideband channel characterisation parameters and the excess loss due to the radiowave propagating through vegetation, indicating that although a propagation loss prediction algorithm might predict adequate coverage the channel quality might not be good enough for communications use. The characteristics of the channel also vary as wind causes swaying of the branches, changing the properties of the multiple paths. Overall, the measurement geometry has a large effect on the multipath characteristics as different geometries have differing multipath possibilities associated with them.