P.R.ENGINEERING COLLEGE, THANJAVUR
 Light is used instead of radio-waves to transmit
information
 Transceiver fitted LED lamps acts like Wi-Fi modems
 LED lamps can light a room as well as transmit-receive
information
 Provides lightas well as data communication
 Radio spectrum is overcrowded, but
the request for wireless data
doubles each year
 Issues regarding radio spectrum,
such as capacity, availability,
efficiency, security are solved
using LIFI.
 Speed of data transmission can be
increased.
 CAPACITY

Spectrum is 10,000 times greater than that of radio
frequency
 EFFICIENCY
 Highly efficient since LED consumes less energy
 AVAILABILITY

Light waves available everywhere.
 SECURITY

Cannot penetrate through walls. Hence data cannot be
intercepted.
 In electromagnetic spectrum, gamma, UV rays are dangerous
for human body.
 IR rays, due to eye safety regulations, are not used
 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
 Pure LiFi, formerly pure VLC, is an original equipment
manufacture firm setup to commercialize Li-Fi products for
integration with existing LED lighting systems
In October 2011, few companies and industries group formed
Li-Fi consortium to promote the high speed optical wireless
systems
 Operational procedure is very simple.
 If LED is ON, digital data ‘1’ is transmitted & if LED is
OFF, digital data ‘0’ is transmitted.
 LEDs varies in intensity so fast that a human eye cannot
detect it
 A controller connected at the back side of these LEDs is
used to code data.
 Also called as 5G optical communication.
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.
To receive data from these lights you need a dongle that acts as a
wireless modem of sorts, which is plugged into your laptop or tablet. The
dongles were a bit smaller than a pack of cards and plug in via USB,
which also provides the power. There’s a sensor that catches the light
coming down and then an infrared component that sends a signal back
up. The overhead lights also have a networking component, so it’s
possible for multiple users to connect to a single light source, and to
move from one light source to another without losing your connection.
 Li-Fi connector and router are the main
components for a network
 Room connector:
 Optical signals cannot penetrate through
walls, in order to provide an optical
WLAN, rooms need to be connected with
each other
 Li-Fi room connector is a replicator, which
sends the data stream from one side of the
wall to the other side via an optical fiber.
 For smaller rooms, connector act as the
only Li-Fi hotspot in the room
 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

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.
 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.
Used in RF restricted environments like chemical industries,
nuclear power plants, petrol pumps
 In home and small offices, Li-Fi can be used to communicate with
devices like
 Laptops
 Internet access
 HD video streaming
 Printer
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.
 The first VLC Smartphone was
presented by Consumer Electronics in
January, 2014
 The phone uses Wysips connect – a
clear thin layer of crystal glass is
added to the small screens
 Smartphone makes them solar
powered.
Smartphone could get 15% more
battery life in a day
Can communicate using Li-Fi.
 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.
 Visible light cannot penetrate through solid objects.
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.
Thus, if Li-Fi technology can be 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.
 Jyoti Rani, PrernaChauhan, RitikaTripathi, ―Li-Fi (Light Fidelity)-The
future technology In Wireless communication‖, International Journal of
Applied Engineering Research, ISSN 0973-4562 Vol.7 No.11 (2012)
 http://visiblelightcomm.com/
 http://www.ijstr.org/final-print/oct2014/Li-fi-A-New-Era-Of-Wireless-Communication-Data-Sharing.pdf
 http://www.digitaltrends.com/cool-tech/why-li-fi-light-internet-could-replace-wi-fi-in-10-years/
 Http://en.wikipedia.org/wiki/li-fi
 Http://www.scribd.com/doc/88340668/seminar-report-on-lifi
 http://gimt.edu.in/clientFiles/FILE_REPO/2012/NOV/23/1353645362045/69.pdf
 http://www.newscientist.com/article/mg21128225.400-will-lifi-be-thenew-wifi.html
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