Li-Fi is a technology that uses light from LED bulbs to transmit data wirelessly. It works by varying the intensity of LED lights faster than the human eye can detect. This allows digital data to be transmitted through the LED. Li-Fi was pioneered in the 1990s and provides higher data rates, more security, and energy efficiency compared to traditional Wi-Fi. It can be used in places where Wi-Fi signals cannot reach or are restricted, such as on aircraft or underwater. While Li-Fi has advantages over Wi-Fi, it also has disadvantages like higher installation costs and inability to pass through opaque objects.

1. Patel Sheetal
M.Sc. Biotechnology
Sem: III
Enrollment no.: 201504101110001

2. What is Li-Fi?
History
How it works?
VLC
Need for Li-Fi
Li-Fi v/s Wi-Fi
Advantages
Disadvantages
Conclusion
References
CONTENT

3.  Li-Fi is transmission of data through illumination,
sending data through a LED light bulb, that varies in
intensity faster than human eye can follow.
WHAT IS Li–Fi ?

4. LIGHT FIDELITY
 Light based Wi-Fi.
 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 and
receive information.
 Provides illumination as well as data communication.

5.  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.
 Herald Haas continues to wow the
world with the potential to use light for
communication.
HISTORY
► Prof. Herald Haas
University of Edinburgh.

6. 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.
 The method of using transmit information wirelessly is
technically referred to as a Visible Light Communication
(VLC), thought it is popular called as Li-Fi, because it can
compete with its radio based rival Wi-Fi connection devices
within rooms.

7. VISIBLE LIGHT COMMUNICATION
 In electromagnetic spectrum, gamma, UV rays, X-rays are
dangerous for human body.
 Infra-red rays, due to eye safety regulations, are not used.

8. NEED FOR Li-Fi
1.4 Million 5 Billion
 Radio spectrum is
congested, but the demand
for wireless data doubles
each year.
 Issues regarding radio
spectrum such as capacity,
availability, efficiency,
security are solved using Li-
Fi.
 Speed of data transmission
can be increased.

9.  In traffic scenario, Li-Fi 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 Li-Fi, Street lights can be used
to send information about the road
condition to the car.
TRAFFIC SCENARIO

10. 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.

11. Li-Fi can even work underwater were Wi-Fi fails
completely, thereby throwing open endless opportunities for
military/navigation operations.
OCEAN BEDS

12.  At home and in small offices, Li-Fi can be used to communicate
with devices like,
 Laptops
 Internet access
 HD video streaming
 Printer
 Wall clock
 Wireless thermostat
HOME AND SMALL OFFICES

13. PARAMETRS Wi-Fi Li-Fi
Li-Fi v/s Wi-Fi

14. 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.

15.  High installation cost of the VLC system.
 Light cannot pass through objects.
 Interferences from the external light sources like sunlight,
normal bulb and opaque materials in the path of
transmission will cause interruption in the communication.
Disadvantages

16. CONCLUSION
Thus possibilities are numerous and can be explored further.
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, fast and efficient wireless data communication.
Li-Fi will make us, proceed towards the cleaner, greener,
safer and brighter future.

17. REFERENCES
• ABHIYANTRIKI: An International Journal of
Development & Technology . A Survey on Li-Fi,
Bhavya & Lokesh, Volume 3, Number 1, January,
2016 (7-12)
• International Journal of Research & Development in
Technology and Management Science, Akshita
Agarwal & Deepali Jhanji, ‘Comparative study: Li-Fi
v/s Wi-Fi’, Vol.21(1), March 2014.
• Watts, Michael.“Meet Li-Fi, the LED-based alternative
to household Wi-Fi". (31 January 2014). Wired
Magazine.

18. THANK YOU…
(Li-Fi)