Li-Fi, or 'light fidelity,' is a technology that transmits data using light-emitting diodes (LEDs), offering high-speed data transmission via visible light communication. Developed by scientists at the University of Edinburgh, Li-Fi overcomes limitations of radio spectrum-based wireless technologies, providing faster speeds, higher bandwidth, and enhanced security. Its potential applications include in-house communication, traffic light systems, aircraft cabins, and utilizing street lamps as internet access points.

2.  LI-FI stands for “Light Fidelity”.
 It is the transmission of data through
illumination ,sending data through a Light
Emitting Diode which varies in intensity faster
than human eye can follow to deliver high
speed data transmission.

3. History
1/25/2015
3
> The technology truly began during the
1990’s in country like Germany, Korea,
and Japan where they discovered LED’s
could be retrofitted to send information.
Harald Hass continues to wow the world
with the potential to use light for
communication.
Professor Harald Haas

4. INTRODUCTON
 It is aVisible Light Communication(VLC) ,technology
developed by scientists including Dr.Gorden Povey ,
Prof Harald Hass and Dr.Mostafa Afgani at University
Of Edinburgh.
 These devices are normally used for illumination
by applying a constant current through the LED.
 Li-fi is the term used for fast and cheap light based
Wi-Fi but it uses light rather than radio waves.

5. Working of LI-FI
How LI-FI works?
• operational procedure is very simple, if the led is on, you
transmit a digital 1, if its off you transmit a digital 0. The
LEDs can be switched on and off very quickly, which gives
nice opportunities for transmitting data.

6. Working of LI-FI

7. Today’s Major DataTransmission
Technique
Today’s majority of data technique uses Radio Spectrum .
Drawbacks of Radio Spectrum
But the fact that it is congested and the demand for
wireless data double each year. Every thing , it seems want
to use wireless data but the capacity is drying up.
Availability :It is available within the range of Base stations
and unavailable in aircrafts.
Efficiency: Consumes huge amount of energy for
transmitting radio waves and to cool the base station cabins
Security: Less secure as it can also pass through walls.

8. How Li-Fi is different from others?
Li-fi is based on LEDs for the transfer of data.
The transfer of data can be with the help of all kinds of light ,no
matter the part of spectrum that they belong to.
The speed of the internet is incredibly high and one can download
movies ,games ,etc. in just a few minutes.
It also removes the limitation to be in a region whereWi-Fi is only
present.

9. Difference between Light Fidelity And
Wireless Fidelity
Parameters Light Fidelity Wireless Fidelity
Medium Uses light as a carrier Uses radio spectrum
Spectrum range Visible light Spectrum Radio frequency spectrum
Speed for DataTransfer Future prospect predict
speed>500 Mbps
Data transfer speed>150 Mbps
Cost Cheaper because free band does
not need license and it uses only
light
Expensive as it uses radio
spectrum.
Operating frequency Hundreds ofTera Hz Usually 2.4 GHz.

10. VariousTransmitting Elements
Lamps
Light Emitting Diodes
 Fluorescent Lamps
 Study Lamps

11. Various Receiving Elements
Avalanche Photo Diode
Image Sensor

12. Potential Application of Li-fi
1.In House Communication :Giga shower
For giga speeds technologies ,the Li-fi consortium has defined Giga
Shower ,Giga MIMO and Giga Spot.
It provides bidirectional data services via several channels to multiple
users.
This is like watching TV channels or listening to different radio stations
where no uplink channel is needed.

13. 2.Traffic Lights
Traffic lights can communicate to each other and vehicles.
Cars ,Traffic lights and other vehicles too have LED-based
headlights so data can be easily transmitted to each other.

14. 3.In Aircraft cabins
This is one of the advantage of li-fi as it could be used in
aircrafts becauseWi-Fi can not be used there.

15. 4.Hospitals
In hospitals li-fi can be used in those instruments which are
capable of light emitting and used for data transmission.

16. 6.Street lamps as free access points
As there are million of street lamps deployed each of them can be used
as free access points for internet and fast data transmission also.

18. Advantages of LI-FI
 Higher Bandwidth (almost 10000 times more)
 Availability
 Efficiency
 High Security
 Easy to use
 Fast data transfer
 Harmless
 Low cost
 High capacity

19. Limitations in front of LI-FI
Light can not pass through objects.
A major challenge facing Li-fi is hoe the receiving device will
transmit back to the transmitter.
High initial cost ofVLC systems.
Interferences from external light sources like sun ,normal
lights and opaque materials.

20. Further Enhancements
Further enhancements can be made in this like using an array of
LEDs for parallel data transmission or mixtures of red , green and
blue LEDs to alter the light’s frequency encoding a different
channel.
Such development promise a theoretical speed of 10 Gbps-
meaning one can download a full high-definition film in just few
seconds.

21. Conclusion
The possibilities are numerous and can be explored
further.
If this technology can be used to practicality ,every bulb
can be used for something like aWi-Fi hotspots to
transmit wireless data.

22. References
1.www.en.Wikipedia.org/wiki/Li-Fi.
2.www.electronicsforu.com.
3.International Journal of advances in computing and
communications .
4.www.ijacc.org