This document provides an overview of Li-Fi technology. It discusses the history, construction, working, advantages, limitations, and applications of Li-Fi. Li-Fi transmits data through visible light communication and was coined by Professor Harald Haas in 2011. It consists of LED bulbs, photo detectors, and other components. Data is transmitted by turning the LED on and off very fast. Li-Fi provides advantages like higher speeds, better security, and no interference. However, light cannot pass through objects, which poses a limitation. Potential applications include use in cars, airports, and medical facilities where Wi-Fi is restricted.

2. CONTENTS:
1.Introduction
2.History
3.Construction of Li-Fi
4.Working of Li-Fi
5.Why only VLC
6.Advantages
7.Limitations and Challenges
8.Applications
9.Conclusion

3. INTRODUCTION
Li-Fi means light fidelity.
It can be used as light based Wi-Fi.
Instead of radio waves it uses visible rays for transmission.
Data can be transmitted through LED light.

4. HISTORY
Li-Fi is a VLC [Visible Light
Communication] .
It is a technology developed by a team of
scientists including Dr Gordon Povey , Prof.
Harald Haas and Dr Mostafa Afghani at the
University of Edinburgh UK
.
 The term Li-Fi was coined by Prof. Haas in
July 2011
Harald Hass, who is considered to be the
Father of Li-Fi says that the heart of Li-Fi
technology lies in the intensity and the potential
of the LEDs
HARALD HASS

5. Li-Fi consists of four primary sub-
assemblies:
Printed circuit board (PCB)
RF power amplifier (PA)
Bulb
Enclosure

6. Electrodes
Bulb Dielectric
material
The bulb is embedded in the
dielectric material
Two degradable electrodes are used.
Dielectric material serves two
purposes-waveguide, electric field
concentrator.
Plasma state-emits light of high
intensity.

7. The operational procedure is very
simple.
If the LED is ON digital 1 is
transmitted, if it is OFF digital 0 is
transmitted.
Lamp driver-codes data into
LED’s.
Photo detector encodes the data

9.  Gamma rays can’t be used as they could be
dangerous.
X-rays have similar health issues.
Ultraviolet light is good for place without people, but
other wise dangerous for the human body.
Infrared, due to eye safety regulation, can only be
used with low power.
Radio
waves
Infra-red
Rays
Visible
Rays
UV
Rays
X-Rays
Gamma
Rays

10. HighSPEED
MoreSECURE
NOElectromagneticInterference
NOTHarmful
SavesPOWER
LowCost

11. LimitationsAndChallenges
Lightcan’tpassthroughobjects.
Interferencesfromexternallightsourceslikesun
light,normalbulbs,andopaquematerialsinthepath
oftransmissionwillcauseinterruptioninthe
communication.
HighinstallationcostoftheVLCsystems.
AmajorchallengefacingLi-Fiishowthereceiving
devicewilltransmitbacktotransmitter.

12. APPLICATIONS
Car Lights
oCars with LED based-Head
lights.
oCars communicate – prevent
accidents
Airports:
oWi-Fi will be slow.
oTo avoid these Li-Fi is used.

13. Visible Light is
safer than RF
RF Restricted
Environment
Medical
• Operating rooms don’t
allow Wi-Fi.

14. 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 a Wi-Fi hotspots
totransmitwireless data.
With its magic of light it can make our world
greener , safer, cleaner and more over a brighter place
tolive.

15. THANK YOU
Presented by
S.UMA SREEMUKHA