Modeling of radiowave propagation in a forested environment

Abstract

Propagation models used in wireless communication system design play an important role in overall link performance. Propagation models in a forested environment, in particular, are especially valuable and complex due to the randomly distributed leaves, twigs, trunks, and trees. This has been an area of interest due to the operational needs of military and non-military domains. Applications in both domains require communication devices and sensors to be operated in forested environments. Various methods have been employed to model propagation loss. There are experimental measurements, empirical models, analytical, and computational electromagnetic methods. Each method has its applicability and limitations. In this thesis, investigation of a three-layer homogenous medium model (air, forest, and ground) by a ray tracing method was carried out. Both transmitting antenna and observation point are within the forest layer. The results from the ray tracing model showed good agreement with the available measurement data up to 100 MHz. Further, better approximation of the transmission loss was observed at separation distances greater than 1 km. Values of the effective electrical properties of the forest played an important role in transmission loss estimation within the forest. After adjustment, the deviation in propagation loss using the ray tracing model achieved an error of 1 dB.