Li-Fi, or light fidelity, is a technology that uses LED lights for wireless data transmission via visible light communication, providing a fast and cost-effective alternative to Wi-Fi. Developed since the 1990s, it enables high-speed data transfer in various applications, although it has limitations such as inability to pass through walls. The technology has substantial future potential to alleviate bandwidth issues and contribute to cleaner energy usage, but it requires direct line of sight to function effectively.

1. LIGHT FIDELITY
PRESENTED BY
PRABHU KIRAN(ECE_4A)
ROLL NO:11621A0407

2. CONTENTS
 INTRODUCTION
 HISTORY
 CONSTRUCTION OF LI-FI
 HOW DOE’S IT WORKS?
 LI-FI VS WIFI
 APPLICATIONS
 ADVANTAGES
 LIMITATIONS
 CONCLUSION

3. INTRODUCTION
 Li-Fi is technology that uses LED's for
transmit data wirelessly .
 Li-Fi means “LIGHT FIDELITY”.
 Li-Fi is fast and cheap fiber version that
use Visible Light Communication(VLC) .

4. Contd……..
 VLC is a data communication that uses
visible light for data transmission.
 Visible light ranges from
400THz(780nm) to 800THz(375nm).
 Its act as transceiver and also used for
lighting the room.

5. LI-FI ENVIRONMENT

6. HISTORY
 In 1990’s countries like Germany, Korea
and Japan found this.
 They discovered that led’s are retrofitted
to send information.
 Porf. Harald Haas worked on it to
improve this technology.

7. Contd….
 On 12th July 2011 he successfully
demonstrated his new invention.
 He used a led table lamp for streaming a
hd video with a speed of 10mbps.
 In the middle he blocked the lamp to
prove that lamp was source of data.

8. Contd….
 At ted global talks he demonstrated with
10mbps.
 Which is fairly good than UK broadband
connection .
 Later after two months he achieved a
speed of 123mbps

9. HARALD HAAS
 Prof. Harald Haas is physicist at
University of Edinburgh in UK.

10. CONSTRUCTION OF LI-FI
 The Li-Fi consists of
4-primary sub-assemblies
. They are
 Bulb
 RF power amplifier
circuit (PA)
 Printed Circuited
Board (PCB)
 Enclosure.
 Construction
diagram

11. Block Diagram

12. HOW DOES IT WORKS?

13. LI-FI VS WIFI

14. PRESENT SENERIO

16. ELECTRO MAGNETI SPETRUM

18. LI-FI HAS AN UPPERHAND DUE TO PARALLEL DATA TRANSMISSION

19. APPLICATIONS
 Airways
 Green information technology
 Free from frequency bandwidth
problems
 Lighting points used as hotspots
 Smart power plants
 Underwater awesomeness
 Medical field (for some instruments)

20. Contd…..
 Airways  Green information
technology

21. Lighting point as hotspot

22. Contd….
 Smart power plant  Underwater
awesomeness

23. Medical field

24. Other areas where we can use li-fi
 Traffic lights
 Street lights
 Shopping malls
 Educational organizations
 Home
 Transport systems

25. Advantages
 High speed
 Low cost
 Easy to use
 Harmless
 Fast data transfer

26. Limitations
 Can’t pass through wall
 External interference
 High installation cost for VLC system
 Still need wi-fi

27. Future scope
 We can transmit data very high speed due to
parallel transmission. And we can reduce the
use of power for modems and Wi-Fi routers.
We are not to worry about high internet
bills. By 2018 we can use a high speed
internet of 10gbps with we can download a
hd movie in 30seconds. We can reduce the
radiation and global warming

28. conclusion
 The possibilities are numerous and can be explored further. If
his technology can be put into practical use, every bulb can be
used something like a Wi-Fi hotspot to transmit wireless data
and we will proceed toward the cleaner, greener, safer and
brighter future. The concept of Li-Fi is currently attracting a
great deal of interest, not least because it may offer a genuine
and very efficient alternative to radio-based wireless. As a
growing number of people and their many devices access
wireless internet, the airwaves are becoming increasingly
clogged, making it more and more difficult to get a reliable,
high-speed signal. This may solve issues such as the shortage of
radio-frequency bandwidth and also allow internet where
traditional radio based wireless isn’t allowed such as aircraft or
hospitals. One of the shortcomings however is that it only work
in direct line of sight.

29. References
 Wiki/Li-Fi(http://en.wikipedia.org/wiki/Li-
Fi)
 Ted global talks/talks/Harald Haas
 http://slideshare.com/li-fitech.html
 seminarprojects.com/s/seminar-report-on-lifi

30. Thanking you