Li-Fi is a visible light communication technology that uses light from LED bulbs to transmit data wirelessly. It was developed by Professor Harald Haas and his team at the University of Edinburgh. Li-Fi uses photo detectors and LED bulbs that can be switched on and off faster than the human eye can detect to transmit data. It provides wireless connections up to 10 times faster than Wi-Fi and has advantages like no interference from radio waves, higher security since light cannot pass through walls, and potential use in environments where Wi-Fi is restricted. Some applications of Li-Fi include use in traffic lights, hospitals, airplanes, and underwater communications.

1. PRESENTED BY:
Munde Pooja S.
GUIDED BY:
Prof. Sushil.V. Kulkarni

2. CONTENT
Introduction
What is Li-Fi?
History
Present scenario
Issue regarding Radio Spectrum
Why only VLC
How Li-Fi works?
Li-Fi v/s Wi-Fi
Advantages
Disadvantages
Applications
Amazing fact about Li-Fi
Conclusion
Reference

3. INTRODUCTION
 Li-Fi is a VLC, visible light communication, technology
developed by a team of scientists including Dr Gordon Povey, Prof.
Harald Haas and Dr Mostafa Afgani at the University of Edinburgh.
Li-Fi is now part of the Visible Light Communications (VLC) PAN
IEEE 802.15.7 standard.
Li-Fi is typically implemented using white LED light bulbs. These
devices are normally used for illumination by applying a constant
current through the LED.
 However, by fast and subtle variations of the current, the
optical output can be made to vary at extremely high speeds.
Unseen by the human eye, this variation is used to carry high-
speed data.

4. What is Li-Fi?
 Li-Fi is transmission of data through illumination
by taking the fiber out of fiber optics by sending
data through a LED Light bulb.
 This varies in intensity faster than Human Eye can
follow.
 It is fast and cheep wireless communication
system which is optical version of Wi-Fi.
 In simple term Li-Fi can be thought of as a light
based Wi-Fi.
 That is ,it uses light instead of radio waves to
transmit the information.

5. HISTORY
 Professor Harald Haas, from the
University of Edinburgh in the
UK, is widely recognised as the
original founder of Li-Fi. He
coined the term Li-Fi and is Chair
of Mobile Comm.
at the University of Edinburgh
and co-founder of pure LiFi.
 The technology truly begun
during the 1990’s in countries
like Germany,Korea and Japan
where they discovered LED’S
could be retroffited to send
information.
 Harald Hass continues to wow
the world with the potential to
use light for communication.
HARALD HASS

6. 1.4 MILLION
5 BILLION

7.  Radio Spectrum is congested but the demand
for wireless data double each year.
 Every thing ,it seems want to use wireless data
but capacity is drying up.
 There are some issues regarding Radio
Spectrum:
1.Capacity
2. Efficiency
3.Availability
4.Security

12. 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 bse
used with low power.
HENCE WE LEFT WITH THE ONLY THE VISIBLE -
LIGHT SPECTRUM.

15. HOW LI-FI WORKS?
Li-Fi is typically implemented using white LED light bulbs at the downlink
transmitter.
Operational procedure is very simple,if the LED is on,you transmit a digital
1,if it’s off you transmit a 0.
The LED can be switched on and off very quicly,which gives nice
opportunities for transmitting data .
Hence all that is required is some LED’S and controller that code data into
those LED’S.
All one has to do is to vary the rate at which
LED’S flicker depending upon the data we want
to encode.
Thus every light source will works as
a hub for data transmission.

16. Fig.Data transmission using LED

17. Fig.Li-Fi environment

18. COMPARISON BETWEEN LI-FI AND WI-FI
LI-FI is a term of one used to describe visible light
communication technology applied to high speed wireless
communication. It acquired this name due to the similarity to
WI-FI, only using light instead of radio waves.
WI-FI is great for general wireless coverage within buildings,
and Li-Fi is ideal for high density wireless data coverage in
confined area and for relieving radio interference issues, so the
two technologies can be considered complimentary.

19. COMPARISON BETWEEN LI-FI AND WI-FI(CONTD..)

20. ADVANTAGES
Wi-Fi is great for general wireless coverage while Li-Fi
is ideal for high density coverage in a confined region.
 It is believed that the technology can yield a speed
more than 10 Gbps, allowing a HD film to be downloaded
within 30 seconds.
Can be used underwater without radio interference
because salt conduct electricity.
Transmission can be blocked by walls,so there is less
risk for data leaking.
Can be safely used on planes because it does not
interfere with radio equipment.

21. DISADVANTAGES
 Is that the light waves cannot penetrate walls.
 In 2012, this technology was demonstrated and it was
detectable upto a distance of 10 meter.
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 system.
Major challenge facing Li-Fi is how receiving device will
transmit back to the transmitter.

22. APPLICATIONS
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.

23. APPLICATIONS(CONTD..)

24. APPLICATIONS(CONTD..)
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.

25. APPLICATIONS(CONTD..)
3-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 drawbacks on radio waves,Li-Fi is introduced.

26. APPLICATIONS(CONTD..)
4-HOSPITALS

27. APPLICATIONS(CONTD..)
5-ON OCEAN BEDS
Li-Fi can even work underwater were Wi-Fi fails
completely ,thereby throwing open endless
opportunities for military or navigation operations.

28. AMAZING FACT ABOUT LI-FI
 Every light source in homes and offices could potentially be
a “Li-Fi” within 20 years.
 When this technology becomes feasible like the Wifi, then
our life will be awesome on earth.
“This is the technology that could start to touch every
aspect of human life within a decade.”

29. 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 and we will proceed towards the
cleaner, greener, safer and brighter future..

30. REFERENCES
1.http://www.electronicsforu.com/electronicsforu/circuitarc
hives/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

31. THANK YOU
ANY QUERIES……..