近土石流發生之天候環境對2.45 GHz無線信號之影響分析

The Analysis of the Climate and Terrain's Impact on 2.45GHz Wireless Signals in a Semi-debris-flow Environment

黃清錦(Ching-Chin Huang) ； 林良宇(Liang-Yu Lin) ； 黃揚智(Yang-Chih Huang) ； 王煥文(Huan-Wen Wang) ； 張隆昌(Lung-Chung Chang)

《電腦與通訊》 131期 (2010/02) Pp. 71-77

https://doi.org/10.29917/CCLTJ.201002.0011

摘要

無線信號本來就很容易受各種環境因素所影響，更何況是土石流發生區之天候地形更是嚴苛致極。在土石流發生區會對2.45GHz無線信號傳輸造成影響的可能因素分別是天候、地形、植被。對於天候因素，大部分論述認為下雨對2.45GHz的無線信號傳輸影響不大，我們實際測試結果也與此相符。至於地形因素，電磁波的不同傳播特性在土石流發生區對通訊品質會有不同影響，但因為感測器是預先佈建且固定不動，所以可以事先以各種方法來降低地形之影響。植被也會影響電磁波傳輸，基本上，不同尺寸的樹葉或樹枝會有不同影響。本論文針對這三個因素對無線信號傳輸的影響提供一個全面了解。

關鍵字

土石流 ； 無線感測網路 ； 電磁波傳播 ； 無線信號衰減 ； 菲涅爾區

並列摘要

Wireless signal is inherently vulnerable to a variety of environmental factors, especially in the debris flow occurrence area where the weather conditions and terrain are extremely harsh. Possible factors arise from debris flow area that may affect 2.45 GHz radio signal transmission are weather, terrain, and vegetation. For the weather factor, our physical experiments show that rain has neglected impact on the 2.45 GHz signal transmission which is consistent to the fact discovered in many researches. Regarding the terrain factor, since communication quality is dependent on the propagation characteristics of electromagnetic waves which may be affected by the terrain factor, we can develop some feasible solutions to alleviate the impact from terrain variation before the sensors are installed. Vegetation is the third factor that will affect the transmission. Basically, different size of leaves or twigs will have different impact on this. In this report we will provides a comprehensive understanding on these three factors to the impact on wireless signal transmission.

並列關鍵字

Debris Flow ； Wireless Sensor Network ； WSN ； Electromagnetic Wave Propagation ； Wireless Signal Attenuation ； Fresnel Zone