臺灣博碩士論文加值系統

本論文分析經由實測之數據在室內繞射(diffraction)之電波統計特性，尤其發射端使用多重天線的天線間距改變時對通道特性之改變。針對不同發射天線間距進行量測實驗時，發射端採用五支均勻線性陣列(Uniform Linear Array, ULA)天線，接收端採用單一天線於接收距離為6米之特定路徑進行動態接收之動作。此類型天線組態稱為多輸入單輸出(Multiple-Input Single-Output, MISO)天線架構，再經由發射端與接收端之間的相關矩陣即可推導出此簡化之MISO通道矩陣。
由於室內環境之構造，使得接收路徑包含直線波(line-of-sight, LOS)與非直線波(non-line-of-sight, NLOS)，無線電波在傳播過程中，因週遭環境障礙物所造成的遮蔽衰落(shadow fading)，所以利用刀緣繞射效應(Knife edge diffraction effect)計算其繞射損失(diffraction loss)。
經本研究發現繞射波本身具有Log-normal分佈，且當發射天線間距愈大時，其累積機率分佈所呈現之標準偏差值愈大。無論在直線波或非線波環境下，當存在有相當的繞射成份時，MMEVR之分佈將呈現非先前研究之結論(當天線間距愈小時，MMEVR愈大)。

The objective of this study is to investigate the property of diffraction wave due to the wave propagation the edge of the wall within a building. The measurement topology was assigned a multiple-input and single-output (MISO) using a 5-element uniform linear array (ULA) transmitter antenna system and a single received antenna, where a 6m of a spatial distance was taken for a dynamic measurements. The MISO channel matrices were derived by using the product of the symmetrical correlation matrices at the BS and MS.
The dynamic measurement are composed of the line-of-sight (LOS) and non-line-of-sight (NLOS) respectively due to the construction of building, which leads to the shadow fading caused by the obstacles of the circumstance; therefore the diffraction loss of wave propagation was calculated by using Knife edge diffraction effect in a building.
From the data analysis, it is not necessarily true that the MMEVR with large value when antenna spacing with small value for both LOS and NLOS environments when diffraction components tends to the significant. The CDF of diffraction wave from our experiments show that log-normal distribution is the best fitting, and it turns out that the smaller antenna spacing and the smaller standard deviation.

第一章 簡介------------------------------------------------------------------------1
1.1 前言------------------------------------------------------------------------1
1.2 研究目的------------------------------------------------------------------2
1.3 研究方法------------------------------------------------------------------3

第二章 室內電波傳播特性分析------------------------------------------------4
2.1 衰落振幅及累積機率分佈---------------------------------------------4
2.1.1 Rayleigh分佈------------------------------------------------------4
2.1.2 Rician分佈---------------------------------------------------------5
2.1.3 Log-normal分佈--------------------------------------------------8
2.2 陣列天線之通道模型--------------------------------------------------9
2.2.1 通道模型----------------------------------------------------------9
2.2.2 通道相關性矩陣------------------------------------------------10
2.2.3 特徵值分佈------------------------------------------------------12
2.3 繞射原理與電波傳播環境之影響----------------------------------15
2.3.1 Fresnel zone ------------------------------------------------------16
2.3.2 直線波------------------------------------------------------------17
2.3.3 反射波------------------------------------------------------------19
2.3.4 散射波------------------------------------------------------------19
2.3.5 繞射波------------------------------------------------------------20

第三章 繞射電波量測方法----------------------------------------------------24
3.1 量測環境敘述----------------------------------------------------------24
3.2 場強量測與資料收集-------------------------------------------------26
3.2.1 量測設備---------------------------------------------------------26
3.2.2 量測設定---------------------------------------------------------29
3.2.3 量測步驟及資料收集------------------------------------------31

第四章 量測結果與分析--------------------------------------------------------34
4.1 電場強度之特性分析--------------------------------------------------35
4.2 繞射損失之特性分析--------------------------------------------------42

第五章 結論-----------------------------------------------------------------------46

參考文獻---------------------------------------------------------------------------48


附錄A 直線波環境，電場強度在個別天線之累積機率分佈------------51

附錄B 非直線波環境，電場強度在個別天線之累積機率分佈---------58

附錄C 直線波環境，五支天線匯集後之信號場強累積機率分佈------65

附錄D 非直線波環境，五支天線匯集後之信號場強累積機率分佈---68

附錄E 直線波環境，相關性矩陣之特徵值及標準差、MMEVR-------71

附錄F 非直線波環境，相關性矩陣之特徵值及標準差、MMEVR----74

附錄G 直線波環境，繞射損失之累積機率分佈---------------------------77

附錄H 非直線波環境，繞射損失之累積機率分佈------------------------84

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