Radio Propagation Studies at 5.8 GHz for Point-to-Multipoint Applications Incorporating Vegetation Effect

摘要

This paper presents an empirical study for fixed wireless links based on IEEE802.16 standard in a vegetated residential environment. Field measurements were conducted for suburban microcell channel by utilizing 5.8 GHz of Unlicensed National Information Infrastructure. A set of comprehensive measurements that covered 10 point-to-multipoint links surrounding Universiti Teknologi Malaysia were selected to investigate the impact of vegetation on propagating radio waves. This suburban location was characterized by trees and terrain blockage. The aim of this study is to develop a path loss model that incorporates vegetation effect. Received signal strength and factors influencing the performance of the signal strength are highlighted here. The accuracy of the proposed prediction model is analyzed, which quantifies that path loss is proportional to the distance of the tree to the receiver, size, density, and number of trees within the vicinity of transmitting and receiving antennas. Observation found that external effect, such as wind significantly affect the signal performance too. The terrain was another factor, which needs to consider into account before deployment of wireless links. Depending on the dynamic characteristics of the presence of trees between the communication links, the measurement results show that the path loss is increased from 5.69 to 33.67 dB. The results obtained are compared to Free Space Loss model, Weissberger model, and ITU-R model. Those established models are used to validate the applicability results obtained by means of root mean square (RMS) error. In view of this research work, a good agreement of the proposed excess loss model achieves the smallest RMS error for links obstructed by single tree and the row of trees.