What is Li-Fi ? Light-Fidelity LI-FI is transmission of data through illumination, sending data through a LED light bulb that varies intensity faster than human eye can follow.

1. ByBy
AvinandanAvinandan JanaJana
B. Tech (CSE) - 6B. Tech (CSE) - 6thth SemSem
Roll No: 18200116007Roll No: 18200116007
CS681CS681

2. A Presentation on LI-FI TECHNOLOGY
for the partial fulfillment of the
requirement for the degree of
Bachelor of Technology in
Computer Science And Engineering.

3. Contents
Introduction
History
Present Scenario
Working Process
Li-Fi vs Wi-Fi
Applications
Challenges for Li-Fi
Conclusion

4. Introduction
What is Li-Fi ?
Light-Fidelity
LI-FI is transmission of data through illumination,
sending data through a LED light bulb that varies
intensity faster than human eye can follow.

5. Introduction

6. History of Li Fi
The technology truly began during the
1990's in countries like Germany,
Korea, and Japan where they
discovered LED's could be retrofitted
to send information. Prof. Harald
Haas continues to wow the world
with the potential to use light for
communication .

7. Present Scenario
Radio Spectrum is congested but the demand for
wireless data double each year. Every thing, it seems
want to use wireless data but the capacity is drying
up.
1.4 Million Base Stations 5 Billion

8. Radio Spectrum Issues
Capacity
• Radiowaves
• 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

9. Radio Spectrum Issues
Availability
• Available within the range of Base stations
• Limited availabity
• Unavailable in aircrafts
Security
• Less secure(passes through the walls)

10. Electromagnetic Spectrum

11. Why only Visible Light Communication
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 bse used with
low power.

12. Working Process
 Operational procedure is very simple, if the led is on, you
transmit a digital 1, if its off you transmit a 0. The LEDs can be
switched on and off very quickly, which gives nice
opportunities for transmitting data. Hence all that us required is
some LEDs and a controller that code data into those LEDs. We
have to just vary the rate at which the LED’s.
 Flicker depending upon the data we want to encode.
 Thus every light source will works as a hub for data
transmission .

13. How Li Fi Works

14. How Li Fi Works
 On one end all the data on the internet will be streamed to a lamp
driver when the led is turned on the microchip converts the digital data
in form of light.
 A light sensitive device (photo detector) receives the signal and
converts it back into original data. This method of using rapid pulses of
light to transmit information wirelessly is technically referred as Visible
Light Communication .

15. Comparison between Lifi and Wifi
Feature LiFi WiFi
Interference
Do not have any interference issues similar to radio
frequency waves.
Will have intereference issues from nearby
access points(routers)
Technology Present IrDA compliant devices
WLAN 802.11a/b/g/n/ac/ad standard
compliant devices
Data transfer
speed
About 1 Gbps
WLAN-11n offers 150Mbps, About 1-2 Gbps
can be achieved using WiGig/Giga-IR
Frequency of
operation
10 thousand times frequency spectrum of the radio 2.4GHz, 4.9GHz and 5GHz
Coverage distance About 10 meters
About 32 meters (WLAN 802.11b/11g), vary
based on transmit power and antenna type
System
components
Lamp driver, LED bulb(lamp) and photo detector
will make up complete LiFi system.
requires routers to be installed, subscriber
devices(laptops,PDAs,desktops) are referred
as stations

16. Application Areas
Li Fi technology is still in its infancy .However some areas
where it seems perfectly applicable are:
1 . Traffic Lights: Traffic lights can communicate to the car
and with each other. Cars have LED-based headlights, LED-
based cack lights, and cars can communicate with each other
and prevent accidents in by exchanging information.

17. Application Areas
2. Intrinsically Safe Environment: Visible Light is more
safe than RF, hence it can be used in places where RF can't
be used such as petrochemical plants.

18. Application Areas
3. Hospitals (In Few Medical Equipements):

19. Application Areas
4. Airlines: Whenever we travel through airways we face the
problem in communication media ,because the whole airways
communication are performed on the basis of radio waves. To
overcome this drawback on radioways , li-fi is introduced.

20. Application Areas
5. Street Lamps (As free Access Points):
• There are millions of street lamps deployed around the
world.
• Each of these street lamps could be a free access point.

21. Limitations or 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.
 Li-Fi requires line of sight
 High installation cost of the VLC systems.
 A major challenge facing Li-Fi is how the receiving device
will transmit back to transmitter.

22. 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.

23. Reference
https://en.wikipedia.org/wiki/Li-Fi
https://lifi-information.com/li-fi-books/
https://www.youtube.com/watch?v=NaoSp4NpkGg
http://www.lifi-centre.com/about-li-fi/what-is-li-fi-
technology/