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Adaptive-learning Code Allocation Technique for Improving Dimming Level and Reducing Flicker in Visible Light Communication

가시광통신에서 Dimming Level 향상 및 Flicker 감소를 위한 적응-학습 코드할당 기법

  • Lee, Kyu-Jin (Department of Electronic Engineering, Semyung University) ;
  • Han, Doo-Hee (Department of ICT Convergence Engineering, Halla University)
  • 이규진 (세명대학교 전자공학과) ;
  • 한두희 (한라대학교 ICT융합공학부)
  • Received : 2022.01.13
  • Accepted : 2022.02.20
  • Published : 2022.02.28

Abstract

In this paper, when the lighting and communication functions of the visible light communication system are used at the same time, we propose a technique to reduce the dimming level and flicker of the lighting. Visible light communication must satisfy both communication and lighting performance. However, the existing data code method results in reducing the brightness of the entire lighting. This causes deterioration of lighting performance and flicker phenomenon. To solve this problem, in this paper, we propose an adaptive learning code allocation technique that allocates binary codes to transmitted characters and optimizes and matches the binary codes allocated according to the frequency of occurrence of alphabets in character strings. Through this, we studied a technique that can faithfully play the role of lighting as well as communication function by allocating codes so that the 'OFF' pattern does not occur continuously while maintaining the maximum dimming level of each character string. As a result of the performance evaluation, the frequency of occurrence of '1' increased significantly without significantly affecting the overall communication performance, and on the contrary, the frequency of consecutive '0' decreased, indicating that the lighting performance of the system was greatly improved.

본 논문에서는 가시광 통신시스템의 조명과 통신의 기능을 동시에 사용할 때, 조명의 Dimming Level 향상과 Flicker 현상을 줄일 수 있는 기법에 대해서 제안한다. 가시광 통신은 통신과 조명의 성능을 함께 만족해야 한다. 그러나 기존의 Data Code Mapping 방식은 전체 조명의 밝기를 감소시키는 결과를 나타낸다. 이는 조명의 성능 저하와 Flicker 현상을 유발한다. 이를 해결하기 위해, 본 논문에서는 전송 알파벳에 대해서 binary code 할당하고, 문자열에 알파벳의 발생 빈도율에 따라 할당된 binary code를 최적화하여 매칭 시키는 적응 학습형 코드 할당 기법을 제안하였다. 이를 통해, 각각의 문자열의 최대 Dimming level을 유지하면서 동시에 'OFF' 패턴이 연속적으로 발생하지 않도록 코드를 할당하여 통신 기능뿐만 아니라 조명으로써의 역할을 충실히 할 수 있는 기법에 대해서 연구하였다. 성능평가 결과, 전체 통신 성능에 큰 영향을 주지 않으면서, '1'의 발생 빈도가 유의미하게 증가하였고 반대로 연속적인 '0' 빈도율이 감소하여 시스템의 조명 성능이 크게 향상된 것을 보였다.

Keywords

Acknowledgement

This paper was supported by the Semyung University Research Grant of 2021

References

  1. S. Shao, A. Khreishah & I. Khalil. (2016). Joint link scheduling and brightness control for greening VLC-based indoor access networks. Journal of Optical Communications and Networking, 8(3), 148-161. https://doi.org/10.1364/JOCN.8.000148
  2. Y. Hong, L. K. Chen & J. Zhao. (2020). Channel-Aware Adaptive Physical-Layer Network Coding Over Relay-Assisted OFDM-VLC Networks. Journal of Lightwave Technology, 38(6), 1168-1177. https://doi.org/10.1109/jlt.2019.2954401
  3. R. Kisacik, M. Y. Yagan, M. Uysal & A. E. Pusane. & A. D. Yalcinkaya. (2021). A New LED Response Model and its Application to Pre-Equalization in VLC Systems. IEEE Photonics Technology Letters, 33(17), 955-958. https://doi.org/10.1109/LPT.2021.3100924
  4. X. Liu, Z. Na, Y. Wang & T. S. Durrani. (2021). Joint Resource Allocation for a Novel OFDM-Based Multicolor VLC Network. IEEE Networking Letters, 3(3), 100-104. https://doi.org/10.1109/LNET.2021.3088311
  5. C. Yeh, C. W. Chow & L. Y. Wei. (2019). 1250 Mbit/s OOK Wireless White-Light VLC Transmission Based on Phosphor Laser Diode. IEEE Photonics Journal, 11(3). 1-5 DOI : 10.1109/JPHOT.2019.2911411.
  6. K. J. Lee. (2018). Dimming Level Control Technique for Lighting / Communication Functions in Visible Light Communication Systems. Journal of Convergence for Information Technology, 8(5), 153-158. https://doi.org/10.22156/CS4SMB.2018.8.5.153
  7. D. G. Kim. (2014). Current status and direction of 5G modile communication. R&D Information and Communication. 23(28).
  8. A. Z. Suriza, S. Akter & M. Shahnan. (2017). Preliminary analysis of dimming property for visible light communication. IEEE 4th International Conference on Smart Instrumentation Measurement and Application (ICSIMA), 1-5
  9. Y. Tanaka, T. Komine, S. Haruyama & M. Nakagawa. (2003). Indoor visible light data transmission system utilizing white LED lights. IEICE TRANS. COMMUN, E86B(8), 2440-2454.
  10. K. J. Lee, H. D. Seo, D. H. Han & K. S. Lee. (2013). Improving the QoS using the Modulation and Coding Selection scheme by temperature characteristic of LED in the LED-ID system. Journal of ITS, 12(1), 66-74
  11. K. T. Kim & K. J. Lee. (2017). Performance Evaluation and Analysis of Zero Reduction Codes for Effective Dimming Control in Optical Wireless Communications using LED Lightings. Journal of Convergence for Information Technology, 7(3), 97-103. https://doi.org/10.22156/CS4SMB.2017.7.3.097
  12. S. Shao , A. Khreishah & I. Khalil. (2016). Joint link scheduling and brightness control for greening VLC-based indoor access networks. IEEE/OSA Journal of Optical Communications and Networking, 8(3), 148. https://doi.org/10.1364/JOCN.8.000148
  13. Z. Feng, C. Guo, Z. Ghassemlooy & Y. Yang. (2018). The Spatial Dimming Scheme for the MU-MIMO-OFDM VLC. System IEEE Photonics Journal, 10(5), 1-3. DOI: 10.1109/JPHOT.2018.2866706
  14. K. H, Lee & H. C. Park. (2011). Modulations for Visible and Light Communications With Dimming Control. IEEE PHOTONICS TECHNOLOGY LETTERS, 23(16), 1136-1138. https://doi.org/10.1109/LPT.2011.2157676
  15. Y. H. Liu , Z. Z.Yang & S. C. Wang. (2010). A novel sequential-color RGB-LED backlight driving system with local dimming control and dynamic bus voltage regulation. IEEE Transactions on Consumer Electronics, 56(4), 2445-2452. https://doi.org/10.1109/TCE.2010.5681126