Vehicular Communication using Li-Fi. Dr Sujan Rajbhandari Senior Lecturer Coventry University

Transcription

1 Vehicular Communication using Li-Fi Dr Sujan Rajbhandari Senior Lecturer Coventry University

2 Content Overview of visible light communication (VLC) Problem with existing RF technology VLC based Solution VLC for vehicular applications 2

3 VLC: Overview Communication through visible wavelengths. Dual functionality: Illumination + communications Source: 3

4 VLC: An Ancient Technology Light was used for signalling from pre-historical time In fact, the first telecommunications device was based on light. 1880: Alexander Graham Bell demonstrated the Photophone before wireless communication by Marconi (1901). In term of the modern communication, optical (Infrared) wireless was developed before Wi-Fi. 4

5 Electric vehicle and VLC Parallel can be drawn with history of the electric vehicle 1835: First practical electric vehicle Popularity of internal combustion engine vehicles Electric vehicle remain dormant for almost a century. Figure: An electric car in 1913 (Source: Wiki) 5

6 Data Traffic: Exploding Source: NCTA Data traffic doubles in every two years 1 1 Cisco: Cisco Visual Networking Index: Global Mobile Data Traffic Forecast Update, ( 6

7 Radio Frequency: Spectrum Crisis 7

8 Steve Jobs: Demo hiccups During the iphone 4 launch (2010), overload Wi- Fi network brings iphone demo to a halt. "So you guys have a choice: Either turn off your Wi-Fi (devices) or I give up. Would you like to see the demos?" he asked the crowd. "Then all you bloggers need to turn off your notebooks. Go ahead, just shut the lids. I'll wait," he said. 8

9 Optical Spectrum: A Possible solution 320 THz of licence-free visible spectrum in comparison to 300 GHz of entire radio frequency Wide availability and popularity of energy efficient solid state lighting (SSL) devices Advances in optoelectronics: SSL can be modulated at high-speed 9

10 VLC: An introduction Advantages License free operation No EMI to existing RF Confined within a closed space Secure Challenges Mobility Blocking and shadowing Dimming Confined within a closed space Low device bandwidth? 10

11 VLC: Transmission System 11

12 White Light Generation: Blue chip + Phosphor LED Colour converter White LED White LED Wavelength (nm) - Cost effective for mass production - Limited communication bandwidth (< 5MHz) 12

13 White Light Generation: RGB - Colour balancing issues - High cost - Higher bandwidth MHz for commercial LEDs - > 500 MHz for micro-leds 1 1 R. X. G. Ferreira et al, High bandwidth GaN-based micro-leds for multi-gbps visible light communications, IEEE Photonics Technol. Lett., vol. 28, no. 19, pp ,

14 Progress in VLC Demonstrations Fig. Progress in the reported data rates using visible LEDs black (circular) dots: without any multiplexing; red (square): spatial multiplexing and blue (triangular): WDM 1 1 S. Rajbhandari et al, A review of Gallium Nitride LEDs for multi-gigabit-per-second visible light data communications, Semicond. Sci. Technol., vol. 32, no. 2, p ,

15 Progress in VLC Demonstrations Transmitter opto-mechanical assembly 9-channel Multiple input multiple output VLC system Based on micro-leds, CMOS driver and APD on CMOS technology Overall data rate ~7 Gbit/s [1] S. Rajbhandari, et al, J. Light. Technol., vol. 35, no. 20, pp ,

16 VLC using Street light Source: Z. Ghassemlooy, et al, Visible light communication: Theory and Applications. Wider coverage areas Optimization by carefully designing lighting system Serve as illumination, communication and localisation 16

17 VLC Applications - Vehicular Networks Intelligent Transportation System (ITS): - vehicles-to- vehicles (V2V) communication - vehicles-to-infrastructure (V2I and I2V) communication. Source: A. Cailean and M. Dimian, IEEE Commun. Surv. Tutorials, no. c, pp. 1 1,

18 Vehicular Networks RF communication - usually omnidirectional covering a lot more than one needs. Interference issues when all vehicles are enabled for communication VLC - For most safety application, position/communication relative to adjust vehicles is sufficient - only adjacent vehicles can communicate Sufficient for most of the applications 18

19 VLC Applications - Vehicular Networks Source: Headlight, tail-light or any other light source - Each light source can be individually modulated parallel data communication. - Traffic light/street light are additional sources for Transportation information Receiver: Solar cell module, in-built camera, or dedicated receiver Source: Emilie Bialic, Cyril Chappaz, Frank Edme, Intelligent Transportation Systems & Photovoltaic LiFi Communication Solution 19

20 VLC Applications - Vehicular Networks T. Yamazato et al., IEEE Commun. Mag., vol. 52, no. 7, pp ,

21 VLC Applications - Tic tac drone Source: Philips Developed by Philips Lighting VLC technology for location and navigate and act autonomously. Ceiling lights to act like an indoor GPS 21

22 VLC Applications Outdoor Localisation GPS may not be available in all the location For autonomous application, precise localisation (with tolerance lower than GPS accuracy) may be necessary. VLC with street-light can be used for precise location (up to cm accuracy). 22

23 References 1. S. Rajbhandari, J. J. D. Mckendry, J. Herrnsdorf, H. Chun, G. Faulkner, H. Haas, I. M. Watson, D. O. Brien, and M. D. Dawson, A review of Gallium Nitride LEDs for multi-gigabit-persecond visible light data communications, Semicond. Sci. Technol., vol. 32, no. 2, p , S. Rajbhandari, H. Chun, G. Faulkner, K. Cameron, A. V. N. Jalajakumari, R. Henderson, D. Tsonev, M. Ijaz, Z. Chen, H. Haas, E. Xie, J. J. D. McKendry, J. Herrnsdorf, E. Gu, M. D. Dawson, and D. O Brien, High-speed integrated visible light communication system: Device constraints and design considerations, IEEE J. Sel. areas Commun., vol. 33, no. 9, pp , H. Chun, S. Rajbhandari, G. Faulkner, D. Tsonev, E. Xie, J. J. D. McKendry, E. Gu, M. D. Dawson, D. O Brien, and H. Haas, LED based wavelength division multiplexed 10 Gb/s visible light communications, J. Light. Technol., vol. 34, no. 13, pp , R. X. G. Ferreira, E. Xie, J. J. D. McKendry, S. Rajbhandari, H. Chun, G. Faulkner, S. Watson, A. E. Kelly, E. Gu, R. V Penty, I. H. White, D. C. O Brien, and M. D. Dawson, High bandwidth GaN-based micro-leds for multi-gbps visible light communications, IEEE Photonics Technol. Lett., vol. 28, no. 19, pp , H. Haas, L. Yin, Y. Wang, and C. Chen, What is LiFi?, J. Light. Technol., vol. 36, no. 6, pp ,

24 Summary Overview of VLC Applications Source: 24

25 Thank You 25

26 Recent Demonstrations: WDM-VLC Demonstrate the feasibility of wavelength division multiplexing (WDM) Improve the achievable data rate 26

27 Recent Demonstrations: WDM-VLC Demonstrate a world record data rate of 10 Gbps using RGB LEDs [1] H. Chun et al, J. Light. Technol., vol. 34, no. 13, pp ,

28 Wide Field of View Receiver To overcome the étendue limit that governs the optical gain and field of view relationship. Solution: Based on fluorescent material (wavelength conversions and total internal reflection) An improvement by a factor of 12 in comparison with the étendue limit Traditional optical concentrator Fluorescent antenna [1] P. P. Manousiadis, S. Rajbhandari, R. Mulyawan, D. A. Vithanage, H. Chun, G. Faulkner, D. C. O Brien, G. A. Turnbull, S. Collins, and I. D. 28 W. Samuel, Optica, vol. 3, no. 7, pp , 2016.