Visible light communication

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Visible light communication

  1. 1.  What is VLC Visible light & Spectrum Indoor VLC scenario History VLC process -Transmitter -Receiver -Modulation VLCC VLC characteristics Comparison with RF & IR Demerits of VLC Applications
  2. 2. What is VLC..???The visible light communication (VLC) refers tothe communication technology which utilizes thevisible light source as a signal transmitter, the air asa transmission medium, and the appropriatephotodiode as a signal receiving component.
  3. 3. Visible light is the form in which electromagneticradiation with wavelengths in a particular range isinterpreted by the human brain. Visible light isthus by definition comprised of visually-perceivable electromagnetic waves. The visiblespectrum covers wave lengths from 380 nm to 750nm.
  4. 4. History of VLC
  5. 5.  First research can be traced to as early as 1998- 1999 Contribution addressing broadband VLC using WLED started appearing in 2001 Visible Light Communication Consortium (VLCC) was established in November 2003 WWRF showed a few more contributions between 2000 and 2006
  6. 6. VISIBLE LIGHT COMMUNICATION PROCESS
  7. 7. Transmitters:-•LED•Fluorescent Light
  8. 8. LED Technical Evolution
  9. 9. LED Modulation• Opto-electronic response V 0 Vd White response Rs L Blue response -5 I Cd Relative response (dB) SPICE Model Cs -10 Rs = 0.9727 L = 33.342 nH -15 Cs = 2.8 nF Cd = 2.567 nF tt = 1.09 ns -20 Luxeon LED -25 0 10 20 30 40 50 freq (MHz) Measured LED small-signal bandwidth
  10. 10. Receiver:-•Photodiode
  11. 11. MODULATION:-•Pulse Position Modulation(PPM)•Frequency Shift Keying(FSK)
  12. 12. The Visible Light CommunicationsConsortium (VLCC) which is mainlycomprised of Japanese technology companieswas founded in November 2003. It promotesusage of visible light for data transmissionthrough public relations and tries to establishconsistent standards.
  13. 13.  Research Advancement and Planning Committee Technical Committee Standardization Committee Popularization Committee
  14. 14. •Human Safety•High Data Rate•Bandwidth•Security•Visibility•Unlicensed Spectrum
  15. 15. •Limited Transmission Power•Regulated Spectrum:•Banned in Sensitive Areas
  16. 16. Limited Data Rates: In IR communications, data rates cannot beincreased beyond a prescribed level as itposes serious threat to human eyes. This canbe attributed to the high energy densitycreated by IrDA due to invisibility.
  17. 17. •LOS Communication•Short Range
  18. 18. • Position Detection• Intelligent Super Mart• Intelligent Transport System• Image Sensor Communications• Networking• Audio Applications• Aesthetics
  19. 19. •LED can be used not only for lighting thehomes but also as means for wireless in-house communication.• VLC can create a revolution in the area ofconsumer networking because of efficiencyand affordability.

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