Li-Fi is a wireless optical networking technology that uses light-emitting diodes (LEDs) for data transmission. It was introduced by Professor Harald Haas at the University of Edinburgh in 2011. Li-Fi works by transmitting data through illumination by controlling the state and rate of flashing of an LED light that varies faster than the human eye. It provides higher speed and more secure data transmission than traditional Wi-Fi and can be used in places where Wi-Fi is unavailable or restricted. While Li-Fi has advantages like high speed and security, it also has limitations such as an inability to pass through opaque objects and susceptibility to interference from other light sources.

1. Prepared by: Manje Gowda K.RPrepared by: Manje Gowda K.R
Dept. of:Dept. of: Electronics & CommunicationElectronics & Communication

2.  Introduction
 History
 Construction
 Working Process
 Li-Fi v/s Wi-Fi
 Applications
 Advantages
 Limitations
 Conclusion

3.  Light-Fidelity
 LI-FI is transmission of data through
illumination, sending data through a smart LED
light bulb that varies intensity faster than human
eye can follow.
 Works on the principle of VLC

6. Introduced by Professor Herald hass, at the university of
Edinburgh.
 Established in 2011 TED global talk
 The promotion of idea through TED helped to start a company,
Pure LiFi
In October 2011, few companies and industries group formed
Li-Fi consortium to promote the high speed optical wireless
systems
Prof. Harald Haas
University of Edinburgh.

7. All the data from Internet is
streamed into lamp driver.
Data from internet is used to
modulate the intensity of LED
light source.
Thus by fast and subtle
variations of current, optical
output can be made to vary at
extremely high speed
The photodetector picks up the
signal
The receiver dongle then
converts the tiny changes in
amplitude into a data stream.

10.  LIFI can be used in
 sensitive areas such as aircrafts for data transmission
without causing interference
 Places where it is difficult to lay optical fibers like
operation theaters
 Traffic scenarios, thereby reducing accidents
 Underwater applications where radio waves cannot
propagate.
 Industries like petrochemical plants, nuclear power plants ,
petrol pumps etc

11. In traffic scenario, LIFI can be used
to communicate with the LED lights of
cars .
 Cars can have LED-based
headlights, backlights and can
communicate with each other.
 This might prevent accidents, by
exchanging information, when the
vehicles are too close
 Using LIFI, Street lights can be used
to send information about the road
condition to the car.

12.  Downloading notes from blogs of teachers
 Often it is necessary to download
lecture notes from the blogs of
respective teachers. With Li-Fi, the
download can be done in the hall itself
 Interactive classroom with interconnected
devices
 The classroom will be more interactive
with the real-time interconnectivity
between 500 devices
 Sharing views & queries with the entire class
 Each person’s queries, views and
clarifications can be shared not only
with the teacher, but with the entire
class.

13. Used in RF restricted environments like chemical industries,
nuclear power plants, petrol pumps

14. Li-Fi can even work underwater were Wi-Fi
fails completely, thereby throwing open
endless opportunities for military/navigation
operations.

15.  The whole airways
communication are performed on
the basis of radio waves.
 Hence passengers face the
problem in communication media.
 This problem can be overcome
by using Li-Fi, since light waves
will not interfere with radio waves.

16.  Data rate greater than 10 Gbps; Theoretically allowing HD
film
to be downloaded in 30 seconds
 Can be used anywhere, even in RF restricted areas; Since light
waves will not interfere with radio waves.
 Mostly LED light bulbs are used, which consumes less energy.
Hence cost efficient.
 As light waves cannot penetrate through walls, the data cannot
be intercepted; Thus provides secured communication.
 Efficient alternative to radio based wireless; since it is quick
and reliable.

17.  Visible light cannot penetrate through solid objects.
 A major challenge of LiFi is how the receiving device will
transmit back to transmitter.
 Interferences from external light sources like sunlight, in the
path of transmission will cause interruption in the
communication.
 Data transmission can be easily blocked by any object placed in
front of LED source.

18. Thus, if Li-Fi technology is put into practical use, every bulb
can be used as an alternative to Wi-Fi hotspots. It provides
simple, faster and efficient wireless data communication. Li-Fi
will make us to proceed towards the cleaner, greener, safer and
brighter future.