室內環境的水平空間分集與垂直空間分集之預估

Abstract

本研究在發展由適應環境模式與統計模式所組成之合併模式，其目的在探 討在室內環境 下之空間分集。統計模式被用來描述由於隨意擺放之散射 體與粗糙表面邊界所造成之散射場分量。藉由比較理論預估及實驗量測之 空間相關係數可知合併模式具有較好的預估精確度。吾人發現傳播環境附 近的散射物體愈多，將導致散射場分量愈多，空間相關性愈差，空間分集 的效率愈高。水平分集較垂直分集之空間相關係數來得小；且水平分集之 分集增益一般亦較垂直分集之分集增益來得大。當雙分支天線的間距約略 為 時，吾人可獲得較佳的分集增益。 In this paper a newly developed hybrid model, composed of a site-specific model and a statistical model is proposed to investigate space diversity in indoor environments. The latter model is used to describe the field scattered by rough surface boundaries and randomly positioned scatters. By comparing the predicted spatial correlation with the measured one 2.44-GHZ , it is shown that the hybrid model has a better prediction accuracy. It is found that environment with heavier cluster introduces stronger scattered fields and leads to a lesser spatial correlation and to a better space diversity performance. The correlation of the horizontal space diversity is weaker than that of the vertical space diversity and the former diversity has a larger diversity gain. Good diversity gains can be obtained with antenna spacing greater than or equal to one wavelength.