this ppt describe about the visible light communications and how the LED has been used to transmit the data when it is off and on.if the LED is off then it sends 0 if the LED is On then it sends 1 so on it sends due to this we can reduce the use of IR radiations

1. VLC
LI-FI
The Future Technology…..
Presented By:
Sibasish Singh Samanta
Regd. No.: 100101ECR064

2. Points to be covered :
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History of Networks
General network scenario
Why only VLC
Introduction
How it Works
Architecture
Issues of Radio waves
Benefits of Light Waves
Applications
Conclusion

3. History of Networks
In the olden days.
Wired networking.
Satellites Communications.
Wireless networking.

4. General network scenario
• Demand for wireless data double each year .
• Low speeds.
• Also as more and more devices get connected to the
network, clogged airwaves.

5. Radio
Waves
Infrared
Rays
Visible
Rays
Ultraviole
t Rays
X- Rays
Gama
Rays
HENCE WE LEFT WITH THE ONLY THE VISIBLE - LIGHT SPECTRUM.

6. Introduction
• Li-Fi can be thought of as a light-based Wi-Fi. It
uses light instead of radio waves to transmit
information.
• Instead of Wi-Fi modems, Li-Fi would use
transceiver-fitted LED lamps that can light a room
as well as transmit and receive information.

7. What is Li-Fi ?
LI FI- LIGHT FIDEALITY
It is transmission of data through illumination ,i.e.
sending data through a LED light bulb that varies in
intensity faster than human eye can follow

8. How it works?
• flickering lights.
• The amplitude of the light is varied .
• Any LED light set if used along with a microchip inside
it can used to detect the changes in the light flickering
thus helping in converting light into data in its digital
form.
• Example video

9. Architecture

10. Issues with radio waves
CAPACITY:
• The current system makes use of radio waves.
• With the increasing number of mobile connections the
availability of the spectrum is getting congested.
• Radio waves forms only a small fraction of the entire
EM spectrum thus making the problem even worse.

11. EFFICIENCY:
• The current system is high on energy consumption.
• 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.

12. AVAILABILITY:
• The availability of the radio waves is yet another major issue now
a days.
• These waves are not much available during the flight travel.
• It is not advisable to use these devices I places like petrol bunks.

13. SECURITY:
• These radio waves can easily penetrate through the walls,
thus letting anonymous users to use the network.

14. ECONOMIC:
• Due the limited availability of the radio waves
the tariff rates are relatively costlier.
• There can be many transparency issues during
the spectrum allocations paving way for many
scams like in the case of 2G.

15. Benefits of light waves
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.

16. EFFICIENCY:
• The data transmission for a unit energy consumption is high in the
case of light waves.
• The data transmission can reach up to thousands of gigabits per
second thus providing very rich data streaming.
• Here in LI FI data bits can be transmitted parallel thus increasing
the efficiency.

17. Availability:
• Light is readily available in every part of the world.
• This makes it easy for people in airplanes to work on the
internet.
• There are an estimated 14 billion light sources on earth
and each can be easily converted into a LI FI hotspot.

18. 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.
• The sources can be used as normal lights when there is no
use for a hotspot.

19. ECONOMIC:
• The tariff rates can be very cheap as light waves are a cheap
resource.
• There can be transparency in spectrum allocations due to its
cheapness.

20. APPLICATION OF LI-FI
Li Fi technology is still in its infancy .However some areas where it seems perfectly
applicable are:-

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.

21. SAFE ENVIRONMENTS
Visible Light is more safe than RF, hence it can be used in places
where RF can't be used such as petrochemical plants , airplanes etc.
 PUBLIC INTERNET HOTSPOTS
 There are millions of street lamps deployed around the world.
Each of these street lamps could be a free access point.

22.  ON OCEAN BEDS
Li-Fi can even wok underwater were Wi-Fi fails
completely, thereby throwing open endless opportunities
for military/navigation operations.

23. Limitations
• 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 systems
• A major challenge facing Li-Fi is how the receiving device will
transmit back to transmitter.

24. 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.