Li-Fi is a technology for wireless communication using light to transmit data and position information. It was invented by Harald Haas at the University of Edinburgh in 2011. Li-Fi uses light-emitting diodes (LEDs) that can be switched on and off at an extremely high speed to transmit data over the visible light spectrum. The LEDs would act as transmitters, while photodetectors act as receivers. Compared to Wi-Fi, Li-Fi has a faster transmission speed of up to 1Gbps, a broader spectrum range, and no interference issues. Potential applications of Li-Fi include use in vehicles, traffic lights, airplanes, underwater, and hospitals due to its availability, efficiency,

2. CONTENTS
•Introduction
•What is Li-Fi
•Working Process
•Applications
•Advantages and Disadvantages
•Li-Fi VS Wi-Fi
•Reference

3. LI-FI (LIGHT FIDELITY)
• Harald Hass, a professor at the University of Edinburgh who began his
research in the field in 2004, gave a debut demonstration of what he
called a Li-Fi prototype at the TED Global conference talk on Visible
Light Communication in Edinburgh on 12th July 2011.

4. LI-FI TECHNOLOGY
• Li-Fi is the transmission of data through illumination
• The heart of this technology is a new generation high brightness led’s.
• Visible Light Communication.
• If led is on , then we transmit a digital signal 1,and if the led is off ,
then we transmit a digital signal 0.
• Li-Fi (Light Fidelity) can be thought of as a light-based Wi-Fi
Technology uses The Visible Spectrum

5. LI-FI ENVIRONMENT

6. IF LED IS ON , THEN WE TRANSMIT A DIGITAL
SIGNAL 1, AND IF THE LED IS OFF , THEN WE
TRANSMIT A DIGITAL SIGNAL 0 .

7. VISIBLE LIGHT COMMUNICATION
Radio
Waves
Infrared
Rays
Visible
Rays
Ultraviolet
Rays
X-Rays
Gama
Rays

8. HOW LI-FI SYSTEM WORKS
Internet
Server
Lamp Driver =
Router
LED
LAM
P
Streaming
Content
Photo Detector = Sensor
Lamp

10. FUTURE APPLICATIONS
• In vehicles and traffic lights, reducing accidents and traffic congestion

11. Street lamps (as free access points)

12. In Airplanes' And Underwater

13. Hospitals

14. ADVANTAGES
Availabil
ity
Efficien
cy
Harmles
s
Fast
Data
Low
Cost
Ease of
use
High
Security

15. DISADVANTAGES
•Light can't pass through objects.
•A major challenge facing Li-Fi is how the receiving device will transmit
back to transmitter.
•High installation cost of the VLC systems

16. WHAT IS THE DIFFERENCE BETWEEN LIFI
AND WIFI
parameters LiFi ‘Light Fidelity’
WiFi ‘Wireless
Fidelity’
Data Transfer Speed Faster transfer speed 1Gbps Data transfer speed 150Mbps
Operation
LiFi transmits data using light
with the help of LED bulbs.
WiFi transmits data using
radio waves with the help of
WiFi router.
Spectrum Range
Visible light spectrum has
10,000 time broad spectrum in
comparison to radio frequency
Radio frequency spectrum
range is less than visible light
spectrum
Interference
Do not have any interference
issues similar to radio
frequency waves.
Will have interference issues
from nearby access
points(routers)
Applications
Used in airlines, undersea
explorations, operation
theaters in the hospitals
Used for internet browsing
with the help of wifi kiosks or
wifi hotspots
Cost
Cheaper than Wi-Fi because
free band doesn’t need license
Expensive in comparison to Li-
Fi because its uses radio

17. REFERANCE
• http://www.ted.com/speakers/harald_haas
• https://en.wikipedia.org/wiki/Visible_light_communication
• http://www.lifi.eng.ed.ac.uk/
• http://pediaa.com/difference-between-wifi-and-lifi/
• http://www.techworld.com/big-data/what-is-li-fi-everything-you-
need-know-3632764/
• http://www.ijser.org/paper/A-Study-on-LiFi-Light-Fidelity-
Technology.html
• And I Search in GOOGLE about all Li-Fi pictrue .