OOK 在可見光通訊系統下具有無閃爍及誤碼更正之編碼法

Abstract

在發光二極體快速普及化的趨勢下,可見光通訊成為新起的研究。可見光通 訊系指利用發光二極體的照明系統額外加上信號源,使發光二極體同時具有照明 以及信號傳輸的功能,不僅可以減少能源消耗並且在特殊場合下,可見光通訊擁 有許多的好處。當可見光通訊要同時應用於照明以及資料傳輸下,亮度會不會因 傳輸資料而改變就成了重要的議題。而本篇論文也提出了一項能消除閃爍問題以 及同時具有自我校正功能的編碼法,以此來保證儘管在傳輸系統很差的情況下, 本篇所提供的編碼法一樣能解決亮度會隨傳輸資料改變的問題。 本論文一共分成五個章節,第一章為研究動機與研究貢獻,第二章介紹了發 光二極體與可見光通訊的原理,並且介紹了人眼的模擬系統,第三章為程式模擬, 使用一套演算法能使亮度不隨傳輸資料而改變,並且更進一步使之具有自我校正 錯誤碼功能,並將這些編碼方式做出各方面的討論與比較,第四章則是把實際的 可見光通訊系統實驗,並驗證第三章的演算法確實能消除亮度隨傳輸資料改變的 情況,第五章為結論以及未來發展。

White Light Emitting Diodes (LEDs) have attracted lots of attention because of their characteristics of low power consumption, high efficiency and long lifetime, and hence visible light communication (VLC) has become a new technology development. VLC means we can use LEDs not only as an illuminating device but also for data transmission. This property will decrease power consumption, and also in certain circumstances it has advantages compared to conventional illuminating devices. When LEDs are used both for illumination and data transmission, the issue of whether light intensity depends on the data being transmitted becomes very important. Therefore, in this thesis an algorithm is provided to eliminate the flicker situation while transmitting data. Also, a coding method is proposed which not only can eliminate the flicker but also has the ability of correcting the error bit. This thesis is divided into five chapters. Chapter 1 gives the motivation and contribution of this research. Chapter 2 introduces the LED illumination theory, VLC system, and sensitivity of the human visual system. Chapter 3 provides the detail of MBNB and MBNB with error correction algorithm, simulation system, results and discussion. In chapter 4, the implementation of the VLC system is demonstrated to verify the simulation results. Chapter 5 gives the conclusions and recommendations for future work.