1. Seminar –
University Institute of Technology, BU
Computer Science and Engineering
Code – CSE 752
Md Quasim – T/2010/1066

2. LI-FI is transmission of data through illumination, sending data
through a LED light bulb that varies in intensity faster than human
eye can follow
-German physicist, Prof. Harald Haas
INTRODUCTION OF LI – FI
Li-fi is a VLC (Visible Light
Communication) technology
developed by a team of scientist
including Dr Gordon Povey, Prof.
Harald Hass and Dr Mostafa Afgani
at the university of Edinburg
Prof. Harald Hass

3. INTRODUCTION OF LI – FI
Light–Fidelity (Li-Fi) technology came into existence in 2011.
The term was first used by Harald Haas in his TED Global talk
on Visible Light Communication.
In October 2011 a number of companies and industry groups
formed the Li-Fi consortium, to promote high-speed optical
wireless systems.
Researchers at the Heinrich Hertz Institute in Berlin, Germany,
have reached data rates of over 500 megabytes per second
using a standard white-light LED.
It allows wireless communication without the use of radio
waves, which can be dangerous in places like oil platforms,
underwater and on planes
Li-Fi can be thought of as a light-based Wi-Fi.

4. Li- Fi ENVIRONMENT

5. Li- Fi ENVIRONMENT

6. HOW IT WORKS
• Heart of Li-Fi technology is high brightness LED’s. The
LED bulb will hold a micro-chip that will do the job of
processing the data.
• 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.

7. HOW IT WORKS
• We have to just vary the rate at which the LED’s flicker
depending upon the data we want to encode.
• A light sensitive device (photo detector) receives the signal
and converts it back into original data.

9. WHY ONLY VLC
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.

10. ADVATAGES OF LI-FI (Visible Light
Communication) OVER RADIO WAVES

11. IN TERMS OF CAPACITY
CAPACITY:
With the increasing number of
mobile connections the availability
of the spectrum is getting
congested.
Radio waves form only a small
fraction of the entire EM spectrum
thus making the problem even
worse.
CAPACITY:
Light is a readily available form of
energy and it covers the major
portion of the EM spectrum.
Visible light spectrum is 10000 times
more compared to radio wave
spectrum.

12. IN TERMS OF EFFICIENCY
EFFICIENCY:
For every unit of energy consumed
the data transmitted is relatively
less.
The data speeds in the current
system can only reach up to a few
hundreds of megabits per second.
EFFICIENCY:
The data transmission for a unit
energy consumption is high in the
case of light waves.
The data transmission can reach up
to gigabits per second thus
providing very rich data streaming.

13. IN TERMS OF AVAILABLITY
AVAILABILTY:
The availability of the radio waves is
yet another major issue now a days.
These waves are not much available
during the flight travel.
AVAILABILITY:
Light is readily available in every
part of the world.
This makes it easy for people in
airplanes to work on the internet.

14. IN TERMS OF SECURITY
SECURITY:
These radio waves can easily
penetrate through the walls, thus
letting anonymous users to use the
network.
This can pose threat if the people
with bad intentions start using it.
SECURITY:
Unlike radio waves light waves
cannot penetrate through opaque
objects thus providing plenty of
network privacy.
No other person can share a
network unless the owner has
permitted them to use it.

15. COMPARISION OF LI-FI AND WI-FI

16. FUTURE APPLICATIONS
• Li-Fi can be used in sensitive areas such as aircraft for data
transmission without causing interference.
• It can be used in places where it is difficult to lay optical fibers
like operation theaters .
• In traffic scenario, Li-Fi can be used to communicate with the LED
lights of cars and might alert drivers when other vehicles are too
close so accident numbers can be decreased.
• It will improve conditions for those working in underwater oil rigs
where radio waves can’t propagate.
• Thousands and millions of street lamps can be transferred to Li-Fi
lamps to transfer data.
• It can be used in petroleum and chemical plants where other
transmission or frequencies could be hazardous.

17. CHALLENGES FOR LI-FI
• Presence of Light is essential.
• Li-Fi requires line of sight.
• It is easily blocked by somebody simply walking in front of
LED source.
• The grand vision: “LED lights with added microchips will let
us transmit thousands of data streams in parallel, enabling
us to access the Internet on smartphones wherever there is
a light source”.

18. 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 hotspot to transmit wireless
data and we will proceed toward the cleaner, greener, safer
and brighter future.

19. REFERENCES
• Issue of Wired world magazine, february 2012(Article
Meet Li-Fi, the LED-based alternative to household Wi-
Fi.)
• http://www.ted.com/talks/harald_haas_wireless
_data_from_every_light_bulb.html
• http://www.lificonsortium.org/
• Journal: International Journal of Innovative Research in
Computer and Communication Engineering ISSN/EISSN:
23209798 23209801
• Year:2013 Volume: 1 Issue: 2
• http://en.wikipedia.org/wiki/Li-Fi