This document provides an overview of Li-Fi technology. It discusses the history of Li-Fi, invented by Dr. Harald Haas in 2011, how it works using LED lights to transmit data, comparisons to Wi-Fi, applications in traffic control and airlines, advantages like using visible light spectrum for high speed data transfer, and limitations such as needing line of sight and not penetrating solid objects. The conclusion envisions a future where every light bulb is a wireless hotspot for cleaner, greener and safer connectivity.

2. CONTENTS
 HISTORY
 INTRODUCTION TO LI-FI
 HOW DOES IT WORKS?
 COMPARISON WITH WI-FI
 OVERCOMING THE 4 ISSUES WITH
RADIOWAVE IN LI-FI
 APPLICATION OF LI-FI
 Advantages of LiFi
 Limitations of LiFi
 Conclusion

3. HISTORY
 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.
 German physicist Dr. Harald Haas, has started
working on transmission of data using visible light
back in 2004.
 In the year 2011 he first introduced to the world this
new technology ,LI FI in the TED talk show.
 He envisions a future where data for laptops and
other mobile devices is transmitted through a light in a
room.

4. INTRODUCTION
 This technology was invented by GERMAN
PHYSICIST HARALD HAAS , from the university of
EDINBURGH ,U.K .
 LI-FI stands for LIGHT FIDELITY and LI-FI is
transmission technology of data through
ILLUMINATION.
 Based on VISIBLE LIGHT COMMUNICATION(VLC).
 VLC is a data communication medium, which uses the
visible light between 400 THz to 800 THz (375 nm) as
optical carrier for data transmission.

5. INTRODUCTION
 LI FI (light fidelity) is data through illumination-
taking the fiber out of fiber optics by sending
data through an LED light bulb that varies in
intensity faster than the human eye can notice.
 At the heart of this technology is a new
generation of high brightness LEDs.
 If the LED is on a digital 1 is transmitted, if the
LED is off then a digital 0 is transmitted.They
can be switched on and off in order to transmit
data continuously.

6. operational procedure is very simple, if the led is on,
you transmit a digital 1, if its off you transmit a 0. The
LEDs can be switched on and off very quickly, which
gives nice opportunities for transmitting data. Hence
all that us required is some LEDS and a controller that
code data into those LEDs. We have to just vary the
rate at which the LED’s
flicker depending upon the data we want to encode
Thus every light source will
works as a hub for data
transmission
HOW DOES LI-FI WORKS?

7. HOW DOES LI-FI WORKS?

8. COMPARISON WITH WI-FI
Characteristic Wi-Fi Li-Fi
Frequency 5 GHz No frequency for light
Standard IEEE 802.11 IEEE 802.15
Range 100 meters Base on LED light
Primary application Wireless local area
networking
Cost Low Medium high
Wireless local area
networking
Data transfer rate 800 Kbps - 11 Mbps >1Gbps
Power consumption Medium Low
Cost Medium High
Security Its medium secure Its high secure

9. Characteristic Wi-Fi Li-Fi
Primary devices Notebook computers,
desktop
computers, servers, TV,
Latest Wi-Fi
mobiles.
Mobile phones, office and
industrial
automatic devices,
notebook
computers, desktop
computers, servers
computers, TV and latest
upcoming devices with
Li-Fi
Primary users Corporate campus users,
homes and
others public places
Traveling employees,
home users, others
public places ,office and
industrial workers
Usage location With in range of WLAN
infrastructure, usually
inside a Building
Where ever light is
available, it may
a public place ,home,
office and road
Etc
Development started 1990 2011
COMPARISON WITH WI-FI

10. OVERCOMING THE 4 ISSUES WITH
RADIOWAVE IN LI-FI
Capacity
Availability
Efficiency
Security

11. APPLICATION OF LI-FI
Traffic Control By Li-Fi

12. Airlines

13. Advantages of Li-Fi
 You Can Use Li-Fi In Hospitals And Aircrafts Also.
 Cheaper Then WiFi , Since Visible Light Spectrum Is A Free
Spectrum Band.
 No License Needed.
 Thousands And Millions Of Street Lamps Can Be Converted
To Li-fi Spots.
 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.

14. Limitations of Li-Fi
 There should be line of sight between sender and receiver
 Visible light cannot penetrate through solid objects
 Interference with other electromagnetic waves makes the
transmitting data to distort
 Light cannot approach the range and penetration of radio waves
 High installation cost of the VLC systems
 A major challenge facing Li-Fi is how the receiving device will
transmit back to transmitter.
 Interferences from external light sources like sun light, normal
bulbs, and opaque materials in the path of transmission will cause
interruption in the communication.

15. 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 Wi-Fi
hotspot to transmit wireless data and we will
proceed onwards the..
Cleaner, Greener, Safer and Brighter future.
Conclusion