This document discusses Li-Fi technology as an alternative to Wi-Fi. It begins by explaining issues with Wi-Fi such as limited radio spectrum bandwidth. It then discusses how other areas of the electromagnetic spectrum like infrared and visible light could be used instead. The document introduces Li-Fi, which uses visible light communication through LED bulbs to transmit data faster than Wi-Fi. It explains how Li-Fi works, provides comparisons to other wireless technologies, and discusses advantages like higher speeds and more available bandwidth. Potential applications and limitations of Li-Fi are also presented.

1. LIGHT FIDELITY
(LI-FI)
PRESENTED BY-
DIVYANSHU VISHAL
9913004009
KALASALINGAM UNIVERSITY

2.  WHAT IS WI-FI???
 ISSUES REGARDING WI-FI (RADIO SPECTRUM)
 PROBLEM WITH OTHER SPECTRUM
 SOLUTION
 VISIBLE LIGHT COMMUNICATION
 PRINCIPLE OF LI-FI TECHNOLOGY
 CONSTRUCTION AND WORKING OF LI-FI
 COMPARISON BETWEEN PRESENT TECHNOLOGY AND LI-FI
 FUTURE APPLICATIONS OF LI-FI
 ADVANTAGES AND DISADVANTAGES
 CONCLUSION
Contents

3. It is a local area wireless technology that allows
an electronic device to exchange data or connect
to the internet using 2.4GHz UHF and 5GHz SHF
radio waves.
It is based on IEE 802.11 standards.
WiFi can be less secure than wired connections.

4. Capacity Availability Efficiency Security

5. Radio
Waves
Infrared
Rays
Visible Rays
Ultraviolet
Rays
X- Rays
Gama Rays
Problem With Other Spectrum
 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 besides with
low power.
HENCE WE LEFT WITH THE ONLY
THE VISIBLE - LIGHT SPECTRUM.

6. Radio Waves Spectrum Visible Spectrum

7. • ONE GERMEN PHYSICIST. HARALD HAAS HAS
COME UP WITH A SOLUTION HE CALLS
“DATA THROUGH ILLUMINATION” D-LIGHT TAKING
THE FIBER OUT OF FIBBER OPTIC
BY SENDING DATA THROUGH AN LED LIGHT BULB THAT VARIES IN INTENSITY
FASTER THAN THE HUMAN EYE CAN FOLLOW.

8. Visible light communication is a data communication medium
using visible light medium between 400 and 800 THz.
The technology uses fluorescent lamps to transmit signals at
10Kbps.
Its is specially designed in such a way that I contains photo diode
receiving signals from light source although in some case cell
phone camera or digital camera will b sufficient

9. How Li-Fi Works ?
 Operational procedure is very simple
 If the LED is ON, you transmit a digital 1’s
 If its OFF you transmit a 0’s.
 The LEDs can be switched ON and OFF very quickly,
which gives nice opportunities for transmitting
data.

10. Data Transmissions By Infrared beam

12. CONSTRUCTION AND
WORKING OF Li-Fi

13. Transmitting Element ( led )

14. Receiving Elements (AVALANCHE PHOTO DIODE)

16. Li-Fi vs Other wireless technologies:
Technology Speed Data density
Wireless (current)
Wi-Fi – IEEE
802.11n
150 Mbps *
Bluetooth 3 Mbps *
IrDA 4 Mbps ***
Wireless (future)
WiGig 2 Gbps **
Giga-IR 1 Gbps ***
Li-Fi >10 Gbps ****

17. Li-Fi vs Wi-Fi:

18. Advantages and Applications

24. Limitation and challenges
 Light can't pass through objects .
 Interferences from external light sources like sun light, normal bulbs, and
opaque materials in the path of transmission will cause interruption in the
communication.
 High installation cost of the VLC systems .
 A major challenge facing Li-Fi is how the receiving device will transmit back
to transmitter.
 Li-Fi requires line of sight.

25. Conclusion
• Immense advancements in science has given a great base to develop such a technology
which could rule the communication in future of the coming years
• The Li- Fi changes the world’s communication and every path of transformation to a very
speedy, accessible, easy, safe transformation based provision
• All we need to do is fit microchip to potential illumination device which does Illumination and
wireless data transformation simultaneously
• Future would project 14 Billion lifi transmitters/access points as they would flourish the
planet’s usage in excess availability
• Li-Fi overcomes problems in issues like
 Capability
 Efficiency
 Availability
 Security & safety
• Lifi is the technology which is for a Cleaner, Greener & Brighter future of planet

26. References
[1] http://www.electronicsforu.com/electronicsforu/cir
cutarchives/view_article.asp?sno=778&title%20=%20Li
Fi%3A+A+New+Paradigm+in+Wireless+Communication&b
_type=new&id=12042
[2]. http://en.wikipedia.org/wiki/Li-Fi
[3]. International Journal of advances in computing & communications,
vol 1, 2013,page no-12 www.ijacc.org
[4]. YouTube.com

27. ..Thank You..
Any Queries ??