臺灣博碩士論文加值系統

隨著高速無線網路以及智慧型手機的普及，資料傳輸在我們日常生活中非常重要，舉凡4G/5G、Wi-Fi及藍芽等技術，雖然提供我們非常便利的通訊品質，但其效能常受到環境上的限制，特別是電磁干擾和頻譜不足的問題，都會明顯影響無線通訊於行動裝置的應用。可見光通訊系統應用於智慧型裝置可大幅改善這些問題，其中一種即是將資料以 QR code 的形式作為光訊號，並使用智慧型裝置上的螢幕與數位相機的鏡頭，分別作為傳送端與接收端，完成兩個端點的資料傳輸，此系統的實現不需要增加任何額外的硬體設備，只須在平台上開發就能完成。
在先前的研究中，QR code 的接收方式為在接收端中以相機連拍的方式擷取 QR code 的影像，當資料遺漏時以要求重傳 (ARQ) 的機制向傳送端要求重新發送，接著加入錯誤更正碼 (FEC) 來保護資料的完整性以減少回傳重送的次數，設計出俱備聚合型混合重傳 (AH-ARQ) 機制的可見光通訊系統。
本論文的研究方向為將先前的研究結果[1]加以改良，為了降低硬體上的負擔，接收資料的方式以QR code掃描器取代連拍系統，錯誤更正碼以 LDPC code 取代 RS code 設計出不同架構的 AH-ARQ 機制，為了提升傳輸速率，再提出不需要要求回傳的更錯機制。本論文最後的實驗數據顯示搭載AH-ARQ回傳機制的可見光通訊系統的資料傳輸率為8.55 kbps，高於ASR-ARQ回傳機制的8.03 kbps，保有FEC但不具回傳機制的資料傳輸率則為8.53 kbps。

In our daily life, data transmission has become important thanks to the developments of communication system based on electromagnetic (EM) techniques. However, the limitations of transmission also appear along with the popularity of wireless communications. Especially, electromagnetic interference (EMI) and frequency spectrum shortage limit the applications of wireless communication in mobile devices. To overcome these limitations, we design a wireless visible light communication (VLC) system applied to the mobile device with liquid-crystal display (LCD) monitor and digital cameras. In fact, the value of mobile device can be added, while wireless VLC system is developed without additional hardware cost. The main concept is to use QR code scanner to read a sequence of quick response (QR) code images. Moreover, the robustness is realized with auto-repeat-request (ARQ) and forward error control (FEC) to resist the transmission error. In advance, aggregated selective repeat auto-repeat-request (ASR-ARQ) method is used to reduce the number of feedback from the receiver. Besides, we also apply the aggregated hybrid auto-repeat-request (AH-ARQ) scheme to effectively against transmission error. Instead of RS codes used in the previous work [1], the low-density parity-check (LDPC) codes are considered with peeling decoding to improve the error control scheme and reduce the number of ARQ. The experiment results show the transmission data rate with AH-ARQ scheme is 8.55 kbps that is better than with ASR-ARQ scheme (8.03 kbps). Besides, FEC scheme without feedback is 8.53 kbps.

ACKNOWLEDGMENTS 1
中文摘要 2
ABSTRACT 3
TABLE OF CONTENTS 4
LIST OF FIGURES 6
LIST OF TABLES 7
I. INTRODUCTION 8
1.1 MOTIVATION 8
1.2 BACKGROUND 9
II. RELATED RESOURCE 12
2.1 QR CODE 12
2.2 ANDROID STUDIO 13
2.3 LOW-DENSITY PARITY-CHECK (LDPC) CODES 13
2.3.1 Representations of LDPC codes 14
2.3.2 Figure representation 17
2.3.3 Encoding of LDPC codes 19
2.3.4 Quasi-Cyclic (QC) LDPC code 19
2.3.5 Iterative decoding algorithm 20
2.3.6 Binary erasure channel (BEC) 23
2.3.7 Peeling decoder and stopping set 24
III. ERROR CONTROL SCHEMES 26
3.1 ASR-ARQ RETRANSMISSION SCHEME 28
3.1.1 Design of transmitter 29
3.1.2 Design of receiver 30
3.2 AH-ARQ RETRANSMISSION SCHEME 31
3.2.1 Design of transmitter 32
3.2.2 Design of receiver 34
IV. EXPERIMENT AND RESULTS 35
4.1 SYSTEM CONFIGURATIONS 35
4.2 PERFORMANCE EVALUATION 36
4.3 COMPARISONS OF REALIZED SYSTEMS 38
V. SUMMARY AND CONCLUSIONS 42
REFERENCE 43

[1]Chang-Ming lee, Po-Han Chen, Ze-An Chen, “Visible light communication system with ARQ applied to smart mobile device,” 2017 International Conference on Applied System Innovation (ICASI), Sapporo, Japan, May 2017.
[2]“802.15.1-2002-IEEE Standard for Telecommunications and Information Exchange between Systems – LAN/MAN – Specific Requirements – Part 15: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Wireless Personal Area Networks (WPANs),” 10.1109/IEEESTD.2002.93621, June 14, 2002.
[3]“ISO/IEC 13157-1:2010. Information technology – Telecommunications and information exchange between systems – NFC Security – Part 1: NFC-SEC NFCIP – 1 security services and protocol, “ICS: 35.110, May 2010.
[4]“802.15.4 – 2003 IEEE Standard for Information Technology – Telecommunications and Information Exchange between Systems – Local and Metropolitan Area Networks Specific Requirements Part 15.4: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (LR-WPANs),” 10.1109/IEEESTD, 2003.94389, Oct 2003.
[5]Chi-Wai Chow, Chung-Yen Chen, and Shih-Hao Chen, “Enhancement of Signal Performance in LED Visible Light Communications Using Mobile Phone Camera,” IEEE Photonics Journal, Vol. 7, Issue. 5, Oct. 2015.
[6]Shih-Hao Chen, and Chi-Wai Chow, “Color-Shift Keying and Code-Division Multiple-Access Transmission for RGB-LED Visible Light Communications Using Mobile Phone Camera,” IEEE Photonics Journal, Vol. 6, Issue. 6, pp. 1–6, Dec. 2014.
[7]International Standard ISO/IEC 18004:2015, “Information Technology – Automatic Identification and Data Capture Techniques – QR Code Bar Code Symbology Specification,” ISO/IEC 18004:2015(E), third edition, Feb. 2015.
[8]Yi Pan, Jing Wu, and Chengnian Long, “MLCS: Face-to-Face Mobile-LCD Communication System based on Visible Light Communication,” 2014 IEEE Wireless Communications and Networking Conference (WCNC), Istanbul, Turkey, pp. 3224–3229, April 2014.
[9]S. Vongpradhip, “Use Multiplexing to Increase Information in QR Code,” 2013 8th International Conference on Computer Science & Education (ICCSE), Colombo, Sri Lanka, pp.361–367, April 2013.
[10]Sin-Rong Toh, Weihan Goh, and Chai-Kiat Yeo, “Data Exchange via Multiplexed Color QR Codes on Mobile Devices,” 2016 Wireless Telecommunications Symposium (WTS), London, pp.1-6, April 2016.
[11]Zhibo Yang, Zhiyi Cheng, Chen-Change Loy, Wing-Cheong Lau, Chak-Man Li, and Guanchen Li, “Towards Robust Color Recovery for High Capacity Color QR Codes,” 2016 IEEE International Conference on Image Processing (ICIP), Phoenix, Arizona, pp.2866-2870, Sept. 2016.
[12]Eryang Chen, and Lin Lei, “Research and Realization of Encoding on QR Code,” 2012 5th International Congress on Image and Signal Processing (CISP), Chongqing, Sichuan, China pp. 1299–1302, Oct. 2012.
[13]Yu Zeng, Yunqing Chen, Shuntian Feng, Kaiyu Zhou, Xianghui Sun, Tong Mao, Lei-Shi, Baohua Lei, Feng Wang, Xiaojun Yan, QuanhuiXu, and Bofei Zhang, “Visible Light Communication System for Mobile Device,” 2014 Sixth International Conf. on Ubiquitous and Future Networks (ICUFN), Shanghai, China, pp.26–28, July 2014.
[14]Watsamon Hogpracha, and Sartid Vongpradhip, “Recognition System for QR Code on Moving Car,” 2015 10th International Conference on Computer Science & Education (ICCSE), Cambridge, United Kingdom, pp. 14-18, July 2015.
[15]Kun Xie, Sébastien Gaboury, and Sylvain Hallé, “Real-Time Streaming Communication with Optical Codes,” IEEE Access, Vol. 4, pp. 284-298, Jan. 2016.
[16]R.G. Gallager, “Low-density parity-check codes,” IRE Trans. Information Theory, Vol. IT-18, PP. 21-28, Jan. 1962.
[17]R. G. Gallager, “Low-density parity-check codes, Cambridge”, MIT Press, 1963.
[18]Thomas M. Cover and Joy A. Thomas, “Element of information theory,” 2006.
[19]M. G. Luby, M. Mitzenmacher, M. A. Shokrollahi and D. A. Spielman, “Efficient erasure correcting codes,” IEEE Transactions on Information Theory, Vol. 47, Issue:2, Feb 2001.
[20]C. Di, D. Proietti, I. E. Telatar, T. Richardson, and R. Urbanke, “Finitelength analysis of low-density parity-check codes on the binary erasure channel,” IEEE Trans. Inform. Theory, Vol. 48, pp. 1570-1579, June 2002.