1. P.R.ENGINEERING COLLEGE, THANJAVUR

2. LIGHT FIDELITY 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
Provides lightas well as data communication

3. NEED FOR LI-FI 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.

4. OVERCOMING WIFI ISSUES
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.

5. VISIBLE LIGHT COMMUNICATION
In electromagnetic spectrum, gamma, UV rays are dangerous
for human body.
IR rays, due to eye safety regulations, are not used

7. LIFE OF LIFI 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

8. HOW IT WORKS? 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.

10. IMPLEMENTATION
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.

11. 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.

12. LI-FI NETWORKS
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

13. APPLICATIONS 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

14. TRAFFIC SCENARIO
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.

15. LECTURE / SEMINAR HALLS
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.

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

17. HOME AND SMALL OFFICES
In home and small offices, Li-Fi can be used to communicate with devices like
Laptops
Internet access
HD video streaming
Printer

18. AIRCRAFTS
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.

19. VLC SMARTPHONES 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.

21. ADVANTAGES
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.

22. LIMITATIONS 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.

23. CONCLUSION
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.

24. References
Jyoti Rani, PrernaChauhan, RitikaTripathi, ―Li-Fi (Light Fidelity)-The
future technology In Wireless communication‖, International Journal of
Applied Engineering Research, ISSN Vol.7 No.11 (2012)

25. THANK YOU