1. Li- Fi
(Light – Fidelity)

2. Contents
- INTRODUCTION - HOW LI-FI IS DIFFERENT ? - HISTORY OF LI-FI - LI-FI CONSTRUCTION - WHY LI-FI COMES ? - HOW LI-FI WORKS ? - LI-FI VS WI-FI - FEATURES - ADVANTAGES - DIADVANTAGES - APPLICATIONS - FUTURE SCOPE - CONCLUSION

3. Introduction Li-Fi means “LIGHT FIDELITY”
Li-Fi is fast and cheap optical version of wi-Fi.
Li-Fi is a technology that uses the LIGHT EMITTING DIODES (LED) to transmit the data wirelessly .
Li-Fi based on VISIBLE LIGHT COMMUNICATION (VLC).
VLC is a data communication medium, which uses the visible light between 400 THz (780 nm) and 800 THz (375 nm) as optical carrier for data transmission.

4. How Li-Fi Is Different ?
- Li-Fi technology is based on LEDs for the transfer of data. - The transfer of the data can be with the help of all kind of light i.e., Light may be Invisible, Ultraviolet or Visible part of spectrum. - The speed of the internet is incredibly high and the user everything in just a few minutes.

5. History of Li-Fi This technology was invented by German Physicist
“HARALD HASS”, from the university of Edinburgh, U.K.
- He demonstrated it in the year 2012.
- But, the technology was truly began during the 1990’s in countries like
Germany, Korea & Japan.
- where they discovered LED’s could be retrofitted to send information
UNIVERSITY OF EDINBURGH :-

6. Li-Fi Construction The Li-Fi product consists of three primary sub-
assemblies:-
Emitter (including bulb)
RF Driver.
Power supply

7. Function of Bulb Assembly
At the heart of LIFI is the bulb sub-assembly where a sealed bulb is embedded in a dielectric material.
The dielectric material serves two purposes:
1) waveguide
2) Electric field

8. RF Drive Power amplifier (PA) assembly that uses an LDMOS device.
Converts electrical energy into RF power.
The PA is designed for ruggedness and efficiency.
The RF driver also contains controls circuit for digital and analog lighting controls.

9. A Typical Li-Fi Scenario

10. Capacity Efficiency Security
Why Li-Fi comes ?
- Due to Issues regarding with Radio frequency Spectrum
- Electromagnetic spectrum
- These are -
Capacity
Availability
Efficiency
Security

11. Radio Spectrum Issues Security Capacity Less secure(passes
through the walls)
Capacity
Radio waves.
Cost and Expensive.
Less Bandwidth compared to other spectrums.
Insufficient spectrum for increasing data.
Efficiency
Millions of base stations consume huge amount of energy for
1.) Transmitting the radio waves
2.) To cool the base station cabins
5% Efficiency
Availability
Available within the range of Base stations.
Limited availability.
Unavailable in aircrafts.

12. Electromagnetic Spectrum

13. Why Only VLC ? Gama rays cant be used as they could be dangerous.
Radio Waves
Infrared Rays
Visible Rays
Ultraviolet Rays
X- Rays
Gama Rays
Gama rays cant be used as they could be dangerous.
X-rays have similar health issues.
Ultraviolet light is good for place without people, but other wise dangerous for the human body.
Infrared, due to eye safety regulation, can only be used with low power.
HENCE WE LEFT WITH THE ONLY THE VISIBLE - LIGHT SPECTRUM.

14. RADIO WAVES FOR WIRELESS
WHAT USES CAN REPLACE
RADIO WAVES FOR WIRELESS
COMMUNICATION ?

15. THROUGH LI-FI - By the use of li-fi we can replace radio waves for wireless communication

16. How Li-Fi Works ?
Procedure is very simple, if the LED is on , then your device transmit a digit
‘1’ & if it is off, then your device transmit a digit ‘0’.
The LED can be switched on & off very quickly, which gives nice
opportunities for transmitting data.
Hence, all that required is some LEDS & a controller that code data into those
LEDS.

17. Comparison Between Li-Fi vs. Wi-Fi

18. Features of Li-Fi CAPACITY - 10,000 Times more spectrum then RW.
- Light boxes are already present, so infrastructure is available already and installed .
EFFICIENCY
- Highly efficient because LED consume less energy.
AVAILABLITY
- Light is present every where.
- Data is present where light is present.
SECURITY
- Light waves does not penetrate through walls.
- Hence they can not be INTERCEPTED.

19. Advantages of Li-Fi It is impossible to achieve more than 10Gbps,
theoretically allowing a high-definition film
to be downloaded in 30 sec.
Mostly powered by LEDs so it is cost efficient
Transmission of data is fast and easy.
MAPS

20. Disadvantages of Li-Fi
Presence of light is essential
There should be line of sight
Works better with fluorescent light and LEDs but very low efficiency with bulbs.

21. Street and traffic light
Applications of Li-Fi
Street and traffic light

22. Under water scenarios

23. Airplane scenarios

24. In RF restricted environment

25. Future Scope
This research report categories the global VLC technology market based on component, application and geography.
Li-fi uses light emitting diodes (LEDs) which are rapidly gaining in popularity for standards light bulbs and other domestic and commercial purposes . They are expected to be ubiquitous in 20 years.
Still under research :-
What will be effect of interference from external light sources like sun light and normal bulbs ?
What about the limited bandwidth of existing copper cable used for electrical connection.

26. Future Scope Where do the connections uplink, how serious are the
modifications needed to the power grid.
How will other devices React if you Inject a high frequency in to
Main ?

27. Conclusion
The possibilities are numerous and can be explored further. If
this technology can be put into practical use , every bulb can be
used something like a Wi-Fi hotspots to transmit wireless data.

28. Thanks !
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