採用實數運算核心哈特利轉換之ACO-OFDM可見光通訊系統架構與電路設計

可見光通訊(Visible Light Communication, VLC)是一種利用可見光調變的通訊技術，所擁有的特性與一般傳輸大不相同，主要來自於傳輸介質是利用可見光而非一般的無線電，可見光相較於無線電擁有較高的安全性，可結合一般照明使用於廣播(Broadcast)或特定場合的單向傳輸，強度通常跟一般照明一樣，由於光線是人眼可見，若光束過強也可經由肉眼觀察出，因此相較之下，可見光通訊具有較高的安全性。可見光還具有其他優點，在後續章節會繼續探討。而本論文探討重點在解決可見光通訊系統中之通道衰減以及抵抗雜訊干擾提升傳輸效率。本論文針對VLC系統設計一套利用不對稱剪裁正交分頻多工調變之規格，其規格是從IEEE 802.11a中改制而成，並利用此規格設計接收機用於VLC系統之中。此接收機包含時頻域轉換、同步和等化等設計。其中時頻域轉換使用較一般正交分頻多工不同於使用哈特利轉換器，其實數運算核心十分適合VLC系統，可達到節省硬體提升效能目的。等化包含通道估測和補償的資料回復設計。同步包含取樣時脈偏移估測補償和符碼區間偵測的設計。本論文使用Matlab與C平台建立模擬系統。電路部分使用Verilog HDL描述，並使用TSMC-90nm製程來實現所設計之電路，以驗證電路設計。

關鍵字

可見光通訊；取樣時脈位移；不對稱剪裁正交分頻多工

並列摘要

Visible light communication is a communication technology, have very different characteristics with general communication technology because of the transmission media. Visible light communication has a higher security compared to radio communication. VLC can be combined with general lighting for use in a particular situation or a one-way broadcast transmission. The intensity of VLC is generally the same as lighting. If the beam is too strong can also be observed cause the transmission media is visible. We will continue to explore in the following sections about other advantages of VLC. The focus of this paper examines the visible light communication system in addressing the channel attenuation and resistance to noise interference to enhance the transmission efficiency. In this paper, design a system for ACO-OFDM (Asymmetrically Clipped Optical OFDM). The specifications from the IEEE 802.11a in restructuring , and using this design specification for the system among VLC. The receiver comprises time and frequency domain conversion, synchronization, and so on. The conversion between time and frequency using Hartley converter instead of general Fourier converter in OFDM, the real arithmetic core of DHT is suitable for VLC. It achieve savings of hardware and enhance the effectiveness. Equalization includes channel estimation and compensation. Synchronization includes sampling clock offset estimation and compensation also have boundary detection.

並列關鍵字

VLC ； Sampling Clock Offset ； ACO-OFDM

參考文獻

[2] P. B. Denyer and D. Renshaw, "VLSI Signal Processing; A Bit-Serial Approach," Addison-Wesley Longman Publishing Co., Boston, Ma, USA,1985.

[4] Xie Zhang, Kaiyun Cui, Minyu Yao, Hongming Zhang, Zhengyuan Xu, "Experimental Characterization of Indoor Visible Light Communication Channels," Communication Systems, Networks & Digital Signal Processing (CSNDSP),56 Poznan, 2012.

[5] Toshihiko Komine, Student Member, IEEE, and Masao Nakagawa, Member, IEEE "Fundamental Analysis for Visible-Light Communication System using LED Lights," IEEE Transactions on Consumer Electronics, Vol. 50, No. 1, FEBRUARY 2004.

[8] Jinlong ZHANG, "Modulation Analysis for Outdoors Applications Of Optical Wireless Communications," Research & Standardization, Radio Access Systems, Nolua Networks Oy PL 372, 00045, Nokia Group, Finland, 2000.

[10] Jean Armstrong, Senior Member, IEEE, "OFDM for Optical Communications," OURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 3, FEBRUARY 1, 2009.

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採用實數運算核心哈特利轉換之ACO-OFDM可見光通訊系統架構與電路設計

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