提升可見光通訊系統傳輸速度與品質的研究探討

Abstract

因為LED的壽命相較其他光源較長以及擁有較小的體積，所以現今越來越多的照明設備都已經被LED所取代，例如：號誌燈、汽車指示燈、顯示面板或是手電筒。若能再持續的降低製造的成本，則LED將會成為室內照明的主要元件。而可見光通訊(visible light communication)就是整合LED照明設備來傳輸訊號，達到高效用的通訊網路。 本論文主要探討兩大部分，第一部分為不使用藍光濾波片的情況下利用FIR數位濾波器的方法改善其通訊的傳輸速度並且使傳輸速率高達10倍的頻寬，比起使用RC電路設計更進一步的優化了系統。第二部分為探討使用不同的編碼格式，來消除有外加日光燈光源雜訊干擾的可見光系統，也成功的在實驗上使用OFDM編碼和Manchester編碼來減輕外加日光燈光源的干擾雜訊，並且討論各編碼的優缺點。

Nowadays light emitting diodes (LED) has been used in many places, such as car indicators, traffic lights, flashlights and displays because of its long life-time and compact size. Since the cost of LED per unit brightness is decreasing, LED is becoming an important device for general in-home lighting system. Using LED lighting system to integrate with the communication system can provide wireless visible light communication (VLC) for local area networks at low cost. This thesis has studied two parts, first is the research about using digital FIR filter to improve the transmission data rate which is 10 times of LED bandwidth without using blue filter. Compared with RC circuit design, it has optimized the system. Second is the research about using different modulation format to mitigate the varying power fluctuations of the fluorescent light. We verify using OFDM and Manchester coding can eliminate the noise generated by the fluorescent light and discuss.