利用高頻譜效益調變技術應用在可見光無線通訊系統

Abstract

在資訊爆炸的年代，藉由網路來吸收訊息的方式與日俱增，也使得對於無線通訊的需求大量增長。現行的無線通訊系統的傳輸速率幾乎不足以滿足人們所需。對於很多研究團隊和公司而言，發展出下一世代的無線通訊系統將是一個很重要的議題，而可見光通訊(VLC)就是其中之一，應用在無線上的可見光通訊還有另一個別名：Li-Fi。其相關的研究起始於這幾年間，當然現下還存在著許多技術上的挑戰，由於一般LED產品多設計給照明使用，所以在通訊上，其通道響應在僅有的100∼200MHz頻寬內有著高達10∼20dB的落差。 在本篇論文裡，我們使用CAP和OFDM兩種通訊訊號去測試所架設的VLC系統的最大資料傳輸量。在這兩種通訊訊號上，我們個別提供了增加資量傳輸量的方法：對於CAP，我們使用預先頻響補償的方式去改善；對於OFDM，我們使用bit-loading去提升資料傳輸量。在實驗中，我們成功傳輸超過3Gbps的資料量在RGB LED – Si PIN系統上。

In the information explosion era, people taking over the information from the internet are growing day by day. It’s also increasing demand for wireless communication. Development next generation wireless communication system will be the important issue for many researches and companies, and Visible Light Communication (VLC) is one of them. For wireless communication system, VLC also call Li-Fi (light fidelity). Its research just starts from recent years, and it also presents many technical challenges owing to the commercial LEDs which using for illumination have the terrible frequency channel response, in only 100MHz to 200MHz bandwidth, it lose nearly 10 to 20dB. In this thesis, we use CAP and OFDM to maximize the data rate in our VLC system. We provide pre-compensation for CAP, and bit-loading for OFDM. Both methods can improve the channel response and increase the data rate. The result is over 3 Gbps in RGB LED – Si PIN by both methods.