微細胞環境下UHF無線電波射入大樓內之傳播機制

Abstract

本研究在發展微細胞環境下，UHF無線電波由戶外入射進入室內不同樓層之路徑損失及其信號變動性和強度之電波傳播機制，探討外牆，窗戶，室內金屬物體，隔牆，走廊對電波傳播的影響。吾人將根據射線追跡技術，以三維射線追跡模式和直接穿透波模式，預估電波在室內環境中，走廊，教室之路徑損失，本研究的傳播模式，預估電波在室內環境中，走廊，教室之路徑損失，本研究的傳播模式均經實驗的驗證，其預估準確度相當合理。此外，量測結果也說明了一些傳播現象：(1)直接波可能是主要的傳播模式。(2)路徑損失並不隨樓層的增加而增加或減少。(3)在同教室內平均路徑損失相差不大。

Mechanism of UHF radiowave propagation into multistory office buildings is explored by using ray-tracing based models, which include a three-dimensional (3-D) ray-tracing model and a direct-transmitted ray (DTR) model. Prediction accuracy of the models is ascertained by the measured data and the measurements are carried out at many specific sites with different propagation scenario. Their measured results also demonstrate some important propagation phenomena. It is found that (1) the direct transmitted wave may be the dominant mode; (2) the path loss neither increases nor decreases monotonically as a function of increasing floor level; and (3) there is not much difference of the average path loss among the receiving positions in the same room.