Li-Fi technology uses visible light communication and LED lights to transmit data wirelessly. It provides several advantages over traditional Wi-Fi such as better security, higher speeds, and an unlicensed spectrum. Li-Fi is based on using light from LED bulbs to transmit data and can support data rates above 1 gigabit per second. While it has limitations like inability to pass through walls, Li-Fi has potential applications in street lights, traffic signals, undersea communication, and areas where Wi-Fi is not practical or allowed.

1. LI-FI TECHNOLOGY
Presented By
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2. ABSTRACT
Li- Fi (light-fidelity) refers to 5G visible light communication system.
using light emitting diode as a medium to hi-speed communication. in the similar
manner WI-FI as the internet as become a major demand people are in a search
of new life of data communication .These the concept of LI-FI is the data
communication on fast flickering of light which is not visible to human eyes.It
has gained huge popularity in the 2 years of invention such technology has
brought not only greener but also safer and cheaper future of communication

3. Contents
 Introduction
 What is Wi-fi ?
 Issues regarding Wi-Fi(Radio spectrum)
 What is Li-Fi?
 Principle of Li-Fi Technology
 Visible Light Communication
 Construction and Working of Li-Fi
 Comparison between Wi-Fi and Li-Fi
 Future Applications of Li-Fi
 Advantages and Disadvantages
 Conclusion

4. Introduction
 Li-Fi means Light Fidelity. In simple terms, Li-Fi can be thought of as a light-
based Wi-Fi.
 It uses light instead of radio waves to transmit information.
 Li-Fi would use transceiver-fitted LED lamps that can light in a room as well as
transmit and receive information.

5. Issues Regarding Wi-Fi
 Capacity
 Availability
 Efficiency
 Security

7. Harald Haas

8. HISTORY
 Harald Haas, a professor at the University of Edinburgh who began his research
in the field in 2004, gave a debut demonstration on Li-Fi prototype at the TED
Global conference in Edinburgh on 12th July 2011.
 He used a table lamp with an LED bulb to transmit a video of blooming flowers
that was then projected onto a screen behind him.

9. Li-Fi(Light-Fidelity)
 Li-Fi can be tought as light based Wi-Fi.
 Li-Fi technology uses the visible spector.
 The term Li-Fi was first used by Harald haas in his Ted golbal talk on visible light
communication in 2011
 In oct 2011 num of companies & industrial group formed consturin for the LI-FI
promation to provide high speed optical WI-FI system

10. Principles of LI-FI
 If led is on transmit a digital signal 1 & off transmit signal 0.
 A controller is connected to the back of the bulbs to code the data to these
leads.

12. Visible light communication
 As the li-fi is based on the visible light communication it is Li-fi is a faster &
cheaper version of Wi-Fi (wireless fidelity).
 VLC is using 400thz to 800thz for an optimal carrier for data transaction.

13. Why Visible Light..?

14. Why VLC….?
 As we know that the GAMA rays , X-rays, ULTRAVIOLOTE rays are
harm full to human body so we don’t use this rays.
 INFRAFER rays are also dangerous due to cyc regulation & this are used
with low power.
 RADIO waves are expensive & they are less secure.
 So we are only left with the visible light spectrum which are not harm full.

15. Construction & working of li-fi
 LI-FI is implemented using a white LED light bulbs at downlink
transmitter.
 As the variation of current is fast the output’s can be made to vary at very
high speed.
 An overhead lamp is fitted with an LED with signal processing technology
streams data embedded in its beam at ultra high speed to photodiodes.
 A receiver dongle then converts the tiny change in amplitude into an
electrical signals which is the converted into data streams & transmitted
to mobiles or computers.

17. Comparison between LI-FI and WI-FI
 WI-FI stands for wireless fidelity.
 Transmits data using radio waves
with the help of WI-FI router.
 Interference issues form nearby
access point.
 Can’t pass through seawater as
interference is more.
 Can’t work in dense region.
 It can pass through the walls we
have to employ the security.
 WI-FI can be employed in open
environment.
 LI-FI stands for light fidelity.
 Transmits data light with the help of
LED bulbs.
 Don’t have any interference similar
to radio frequency waves.
 Can pass through salty sea water as
the interference is low.
 Works in dense region.
 Can’t penetrate through walls so
security is not needed to employ.
 LI-FI is effected by the sun light so
it should work in closed
environment.
WI-FI LI-FI

19. Future applications
Visible Light is more safe than RF,hence
it can be used in ere RF can’t be used such
as petrochemical plants.

21. Traffic application

22. Street lights

23. Under water

24. LI-FI in Airplanes

25. Advantages
 Availability
 Efficiency
 Harmless
 High security
 Ease of use
 Fast data transfer
 Low cost

26. Disadvantages
 Can’t transmit through wall.
 How the receiving device will transmit back to the transmitter.
 High initialization cost of VLC system.
 Interference from external light sources like sunlight ,normal bulbs &
opaque materials.
 Low range coverage.
 The security can’t be provided for the li-fi if the person is under the light.

27. Conclusion
 The possibilities are numerous & can be explored in future.
 In split of disadvantages if this technology can be put into use every bulb
can be used like WI-FI hotspot.
 By using LI-FI we can promote to the CLEANER,GREENER,SAFER&
BRIGHTER FUTURE.

28. Any Quries…?

29. Thank you