1. Introduction to Li-Fi
Technology
O Iliad mehmandoost
O Assistant Prof.:
Dr. Keshtgari

2. Objectives
O What is li fi ??
O Working of li-fi !!!
O Construction of Li-Fi???
O Comparison between Wi-Fi & Li-Fi
O How Li-Fi is different??
O Applications of Li-Fi….
O Advantages of Li-Fi….
O Conclusion ….
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3. What is Li-Fi
O Li-Fi is transmission of data through
illumination by taking the fiber out of fiber
optics that varies in intensity faster than the
human eye can follow.
O It is the fast and cheap Wireless
communication system which is optical
version of Wi-Fi.
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4. Abstract of Li-Fi Technology
O Li-Fi can be thought of as a light-based Wi-Fi.
That is, it uses light instead of radio waves to
transmit information.
O And 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.
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5. History
O The technology truly began
during the 1990's in countries
like Germany, Korea, and
Japan where they discovered
LED's could be retrofitted to
send information. Harald
Haas continues to wow the
world with the potential to
use light for communication
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6.  on 12th July 2011. He used a table lamp with an
LED bulb to transmit a video of blooming flowers
that was then projected onto a screen behind him.
During the event he periodically blocked the light
from lamp to prove that the lamp was indeed the
source of incoming data.
 At TEDGlobal, Haas demonstrated a data rate of
transmission of around 10Mbps -- comparable to a
fairly good UK broadband connection. Two months
later he achieved 123Mbps.
 Back in 2011 German scientists succeeded in
creating an800Mbps (Megabits per second)
capable wireless network by using nothing more
than normal red, blue, green and yellw 0
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7. LI FI- Light Fidelity
O Li-Fi is a VLC, visible light communication,
technology developed by a team of scientists
including Dr Gordon Povey, Prof. Harald Haas
and Dr Mostafa Afgani at the University of
Edinburgh.
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8. O Li-Fi is now part of the Visible Light
Communications (VLC) PAN IEEE 802.15.7
standard. “Li-Fi is typically implemented using
white LED light bulbs. These devices are
normally used for illumination by applying a
constant current through the LED
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9. O In simple terms, Li-Fi can be thought of as a
light-based Wi-Fi. That is, it uses light instead
of radio waves to transmit information. And
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. Since simple light bulbs are used,
there can technically be any number of access
points.
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10. O The LEDs can be switched on and off very quickly,
which gives nice opportunities for transmitting
data. Hence all that is required is some LEDs and a
controller that code data into those LEDs. All one
has to do is to vary the rate at which the LED’s
flicker depending upon the data we want to
encode. Further enhancements can be made in
this method, like using an array of LEDs for parallel
data transmission, or using mixtures of red, green
and blue LEDs to alter the light’s frequency with
each frequency encoding a different data channel.
Such advancements promise a theoretical speed
of 10 Gbps – meaning one can download a full
high-definition film in just 30 seconds.
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11. O
This technology uses a part of the electromagnetic
spectrum that is still not greatly utilized- The Visible
Spectrum. Light is in fact very much part of our lives for
millions and millions of years and does not have any
major ill effect. Moreover there is 10,000 times more
space available in this spectrum and just counting on the
bulbs in use, it also multiplies to 10,000 times more
availability as an infrastructure, globally.
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12. Working of Li-Fi
O Its working is much simply explained as
follows:
O If the LED is on, the digital 1 is transmitted.
O And if it is off, the digital 0 is transmitted
O It is possible to encode data in the light by
varying the rate at which the LEDs flicker on
and off to give different strings of 1s and 0s
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13. Introduction to Li-Fi technology
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14. Construction of Li-Fi…
Li-Fi product consists of 4 primary subassemblies
O Bulb
O RF power amplifier circuit(PA)
O Printed Circuit Board(PCB)
O Enclosure
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15. Construction of Li-Fi…
O The PCB controls the electrical inputs and
outputs of the lamp and houses the
microcontroller used to manage different
lamp functions.
O An RF (radio-frequency) signal is generated
by the solid-state PA and is guided into an
electric field about the bulb.
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16. O The high concentration of energy in the
electric field vaporizes the contents of the
bulb to a plasma state at the bulb’s center;
this controlled plasma generates an intense
source of light.
O All of these subassemblies are contained in
an aluminum enclosure
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17. Introduction to Li-Fi technology
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18. Comparison between Li-Fi & Wi-Fi…
O Wi-Fi is great for general wireless
coverage within buildings, and Li-Fi is
ideal for high density wireless data
coverage in confined area and for
releiving radio interference issues, so
the two technologies can be considered
complimentary.
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19. Introduction to Li-Fi technology
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20. How Li-Fi is diferent?
O Li-Fi technology is based on LEDs for
the transfer of data
O The transfer of data can be with the
help of all kind of light i.e Light may be
invisible, Ultraviolet or visible part of
spectrum
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21. Introduction to Li-Fi technology
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23. 12/22/2013
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24. Capacity
• Radiowaves
• Cost and expense
• Less Bandwidth compared to other spectrumsInsufficient
spectrum for increasing data
Efficiency
• Millions of base stations consume huge amount of energy for:
– Transmitting the radio waves
– To cool the base staions cabins
• 5% efficiency
Availability
• Available within the range of Base staions
• Limited availability
• Unavailabe in aircrafts
Security
• Less secure(passes through the walls)
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25. For giga-speed technologies, the Li-Fi Consortium
defined GigaShower, GigaSpot and GigaMIMO
models
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26. O GigaShower and Giga-MIMO are the other models for in-
house communication. There a transmitter or receiver is
mounted into the ceiling connected to, for example, a
media server
O GigaShower provides unidirectional data services via
several channels to multiple users with gigabit-class communication speed over several metres. This is like
watching TV channels or listening to different radio
stations where no uplink channel is needed. In case
GigaShower is used to sell books, music or movies, the
connected media server can be accessed via Wi-Fi to
process payment via a mobile device. GigaSpot and
GigaMIMO are optical wireless single- and multi-channel
HotSpot solutions offering bidirectional gigabit-class
communication in a room, hall or shopping mall for
example.
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27. Applications of Li-Fi:
Some of the applications of Li-Fi are given
below:
O Medical field
O Airlines
O Power plants
O Military operations
O Under sea water
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28. Uses on applications
O Used for modern medical instruments
O Light is inherently safe and can be used
in places where radio frequency
communication is often deemed
problematic, such as in aircraft cabins
or hospitals
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29. Airlines
Whenever we travel through airways we face the problem in
communication media ,because the whole airways communication
are performed on the basis of radio waves. To overcomes this
drawback on radioways , li-fi is introduced.
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30. ON OCEAN BEDS
O Li-Fi can even wok underwater were
Wi-Fi fails completely, thereby throwing
open endless opportunities for
military/navigation operations.
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31.  There are millions of street lamps deployed around the
world.
O Each of these street lamps could be a free access point.
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33. Limitations or challenges
O light can't pass through objects
O Interferences from external light sources like
sun light, normal bulbs, and opaque materials
in the path of transmission will cause
interruption in the communication.
O High installation cost of the VLC systems
O A major challenge facing Li-Fi is how the
receiving device will transmit back to
transmitter.
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