臺灣博碩士論文加值系統

可見光通訊技術 (Visible Light Communication) 在近年來已被廣泛的討論，其基本設計是考慮燈具在照明的同時增加通訊功能，利用可見光的特性來補足Bluetooth、NFC (Near Field Communication) 等無線近場通訊技術在通訊安全、增加傳輸頻寬等相關議題。
本論文考慮近距離的可見光通訊，提出一種新的通訊系統，主要利用改變手機螢幕亮度傳送訊號，讓相機鏡頭接收的能量差異來區分不同的信號，在手機不增加任何新元件的情況下，完成傳輸系統的設計。考慮到使用LCD螢幕亮度傳送訊號，本論文提出用脈波振幅調變(Pulse Amplitude Modulation ，PAM)來傳送訊號，不使用後端訊號處理單元的運算支援，直接用感測的光能量來分析信號的種類，並使用雙鏡頭來接收不同位置測得的光強度，利用最大似然估計 (Maximum likelihood estimation，ML)判斷傳送訊號，並結合兩個接收訊號判斷傳送訊號以降低錯誤率，同時優化傳送端的光能量位階信號能量分佈。實驗結果發現將接收端能量相加能降低系統的訊號錯誤率並擁有最大的通道容量，傳送端使用固定接收端接收能量為依據去設計傳送端亮度位階有較低的錯誤率。

Visible Light Communication (VLC) has been widely discussed in recent years. The basic concept of VLC is send information using the same light signal while performing illumination. Considering of VLC characteristic, VLC can increase transmission bandwidth and communication security according to the weakness of short-distance communication such as Bluetooth and NFC (Near Field Communication).
This paper considers the close-range visible light communication, proposes a new communication system, which uses the difference of the screen brightness of the mobile phone to transmit signals and use the camera lens as the receiver to receive signals. In the mobile phone without adding any new components, complete the transmission system design. Consider using the LCD brightness to transmission signal, this paper presents Pulse Amplitude Modulation (PAM). The system provided does not require the use of back-end signal processing. In the proposed scheme, the receiver determines the signal with luminous intensity. Proposed system uses dual-lens to receive luminous intensity at different locations, and use Maximum likelihood (ML) estimation to determine the signal. Through the proposed dual-lens receiver, not only the error rate can be decreased, but also optimize the signal energy distribution of light energy level at the transmitter. From the experimental results, added dual-lens receiver signals can reduce error rate and having biggest channel capacity. The transmitter uses fixed receiving energy to design the transmitter brightness level having lower error rate.

致謝詞 I
中文摘要 II
Abstract III
圖目錄 V
表目錄 VI
第1章 緒論 1
第1.1節 前言 1
第1.2節 研究背景與動機 1
第2章 相關研究 5
第2.1節 可見光通訊技術 5
第2.1.1 節 On-Off Keying (OOK) 8
第2.1.2 節 Variable Pulse-Position Modulation (VPPM) 9
第2.1.3 節 Color-Shift Keying (CSK) 10
第2.1.4 節 Pulse Amplitude Modulation (PAM) 11
第2.2節 光能量的測量 11
第2.3節 螢幕對主鏡頭能量分佈 12
第3章 近場可見光系統設計 13
第3.1節 使用手機之近場可見光通訊系統 13
第3.2節 傳送端螢幕亮度位階設計 14
第3.3節 接收端訊號估計設計 16
第4章 實驗結果分析與討論 20
第4.1節 接收端估計方法效能分析 20
第4.2節 亮度位階設計效能分析 23
第5章 結論與未來展望 32
參考文獻 33

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