臺灣博碩士論文加值系統

在本論文中，主要探討在可見光通訊(Visible Light Communication, VLC)系統下，提出訊號合併技術應用於光感測陣列接收器上，所能提供的效能改善。由於傳統上接收器為光電二極體(Photoelectric-Diodes, PD)，它是將光訊號轉換成電訊號，所以是無法分辨出不同的輸入光譜，而這項缺點會造成在接收端無法消除干擾和雜訊，並且很難達到運用分波長多工技術(Wavelength Division Multiplexing, WDM)去接收不同波長的輸入訊號。
所以提出光感測器陣列是用在接收端來消除干擾和雜訊，並且運用分波長多工技術。根據多天線通訊系統和訊號合併演算法概念，如最大訊號對干擾加雜訊比率合併(Maximum SINR Combining, MSC)、最大比率合併(Maximum Ratio Combining, MRC)、等增益合併(Equal Gain Combining, EGC)、選擇性合併(Selection Combining, SC)與匹配濾波器合併(Matched Filter Combining, MFC)的五種訊號合併技術來設計出適當的權重值，再分別給各光感測器加權，便可有效地使輸出訊號雜訊比(Signal to Noise Ratio, SNR)或訊號干擾比(Signal to Interference Ratio, SIR)或訊號對干擾加雜訊比（Signal to Interference plus Noise Ratio, SINR）得到最佳極大值。在模擬顯示我們的確能藉由低成本的光感測器陣列來消除干擾及雜訊，便能有效的提升輸出效能。

The goal of this thesis is to research into multi-antenna diversity techniques for spectrum sensor array receiver in visible light communication systems and to improve the performance of this system. Conventionally, photoelectric-diodes are implemented to convert optical signals into electronic signals. Since conventional photoelectric-diodes cannot distinguish inputs of different spectra, using conventional photoelectric-diodes have the disadvantage that the system is vulnerable to interference and noise, and hard to achieve wavelength division multiplexing (WDM) for light sources of different wavelengths.
In this work, a spectrum sensor array is proposed to be implemented on the receiver side to achieve interference and noise rejection.　By proper design of the weightings for individual spectrum sensor, the effective output signal-to-noise ratio (SNR) or signal-to-interference ratio (SIR) or signal-to-interference-plus-noise ratio (SINR) can be maximized. Following the concept of multi-antenna communication systems, signal fusion algorithms　include maximum SINR combining (MSC), maximum ratio combining (MRC), equal gain combining (EGC), selection combining (SC) and matched filter combining (MFC) are presented. The simulation results demonstrate robust interference and noise rejection is made possible using the low-cost spectrum sensor array.

摘要 i
ABSTRACT ii
誌謝 iii
目錄 iv
表目錄 vi
圖目錄 vii
第一章 緒論 1
1.1 前言 1
1.2 研究動機與方法 2
1.3 論文架構 3
第二章 可見光通訊系統與相關知識介紹 4
2.1 可見光通訊 4
2.1.1 可見光通訊系統基本架構 6
2.1.2 可見光通訊系統傳送端 7
2.1.2.1 電力線通訊 7
2.1.2.2 發光二極體 8
2.1.2.3 On-Off Keying 10
2.1.2.4 分波長多工技術 12
2.1.3 可見光通訊系統接收端 13
2.1.3.1 光電二極體 13
2.1.3.2 光感測器陣列 14
2.2 接收效能評估定義 17
2.2.1 訊號雜訊比 17
2.2.2 訊號干擾比 18
2.2.3 訊號對干擾加雜訊比 19
第三章 訊號合併演算法介紹 21
3.1 同調天線陣列架構 21
3.2 多天線分集演算法 22
3.2.1 SC演算法 22
3.2.2 EGC演算法 23
3.2.3 MRC演算法 24
3.2.4 MFC演算法 29
3.2.5 MSC演算法 30
第四章 模擬接收效能的比較與分析 33
4.1 訊號雜訊比 33
4.1.1 定義光感測器輸出雜訊 33
4.1.2 模擬接收效能 34
4.1.3 MRC權重估測錯誤之效能影響 41
4.1.4 感測器多寡之效能影響 42
4.2 訊號干擾比 46
4.3 訊號對干擾加雜訊比 58
第五章 結論與未來研究 76
5.1 結論 76
5.2 未來研究 77
參考文獻 78

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