Li-Fi is a wireless optical networking technology that uses light-emitting diodes (LEDs) for communication. It was invented by Professor Harald Haas and is a faster, more secure, and cheaper alternative to Wi-Fi. Li-Fi uses visible light communication and LED light bulbs to transmit data, allowing for much higher speeds than Wi-Fi. Some challenges remain around light not passing through objects and interference from other light sources, but Li-Fi shows promise for applications like traffic lights, hazardous environments, and undersea use where Wi-Fi cannot reach.

1. Li-Fi
Technology

2. Introduction
• What is Li-Fi ?
• *Li-Fi stands for light fidelity.
• *It is bidirectional high speed and fully networked wireless
communication technology similar to WiFi.
• *Li-Fi is a technology that uses the Light Emitting Diodes
(LED) to transmit data wirelessly.
• *Li-Fi is based on Visible Light Communication (VLC).
• *This varies in intensity faster than human eye can follow.
• *Li-Fi is fast and cheap optical version of Wi-Fi.

3. History
Professor Harald Haas
 Professor Harald Haas, from the
University of Edinburgh is the founder of
Li-Fi.
 In 1990 countries like Germany and
Japan found that data can be transmitted
through led’s.
 Implemented the concept of li-fi for the
first time on 12th July,2011.
 The first Li-Fi smartphone prototype
was presented at the Consumer Electronics
Show in Las Vegas from January 7–10 in
2014.

4. Present
Scenario
• Radio spectrum is congested but
the demand for wireless data
double each year.
• Bandwidth limitation.
• Data Security.

5. Working
Process
• Operational procedure is very simple, if
the led is on,transmit a digital 1 .
• if its off then transmit a 0. The LEDs can
be switched on and off very quickly, which
gives nice opportunities for transmitting
data. Hence all that required is some LEDs
and a controller that code data into those
LEDs. Wehave to just vary the rate at which
the LED’s .
• hus every light source will works as a hub
for data transmission .

6. Li-Fi vs Wi-Fi
S.N Parameters Li-Fi Wi-Fi
1. Speed for data
transfer
Faster transfer
speed(>150Gbps)
Less transfer speed (1 Gbps)
2. Medium through
which data transfer
occurs
Used light as carrier Used radio Spectrum
3. Spectrum range 10,000 times more than Radio
frequency
Less than visible light spectrum
4. Cost Cheaper than Wi-Fi because
free band doesn’t need license
& it uses light
Expensive than Li-Fi because
it uses radio spectrum
5. Operating frequency Hundreds of Tera Hz 2.4 Ghz
6. Coverage About 10m About 32 meter vary according
to bandwidth.

7. Applications
• Li Fi technology is still in
its minority .However some areas where
it seems perfectly applicable are :
• Traffic lights
• virtually Safe Environment
• On ocean Beds
• Street Lamps(As Free Access Point)

8. Applications
• virtually safe environment:
• Visible Light is more safe than
RF, hence it can be used in
places where RF can't be used
such as petroleum plants.

9. Applications
• On Ocean Beds:
• Li-Fi can even
work underwater were Wi-Fi
fails completely, thereby
throwing open endless
opportunities for
military/navigation operatio
ns.

10. Applications
• Street Lamps(As Free Access)
• There are millions of
street lamps developed
around the world.
• Each of these street lamps could
be a free access point.

11. Challenges
for Li-Fi
 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
 A major challenge facing Li-Fi is
how the receiving device will
transmit back to transmitter.

12. 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.
12

13. thank you