This document discusses Li-fi technology, which uses LED light bulbs to transmit data wirelessly. It begins with an introduction to Li-fi and how it works by varying the intensity of light faster than the human eye can detect. The history of Li-fi development is then outlined, along with the present need for alternatives to radio spectrum. The document explains how Li-fi works and compares it to Wi-fi. Advantages of Li-fi include high data rates, security, and lack of health effects. Applications that could benefit from Li-fi are also proposed, such as traffic lights, hospitals, and street lamps providing wireless access.

1. Li-fi Technology
The Optical Wireless Network
PRESENTED By ~
S. PARVEEN SINGH
R. NO. ~ 151340104026
BRANCH ~ M.E. ( 3rd year )
SUBMITTED TO – Mr. divyaprakash
INSTITUTE OF TECHNOLOGY
GOPESHWAR

2. Contents
Introduction
History
Present scenario
How Li-fi works ?
Li-Fi v/s Wi-Fi
Advantage of Li-Fi
Disadvantage of Li-Fi
Applications
Conclusion
Reference

3. Introduction
 What is Li-Fi ?
• Li-Fi is a transmission of data through
illumination i.e. sending data through a led
light bulb that varies in intensity faster than
human eye can follow.
• Li-Fi – light Fidelity
• Li-Fi data is transmitted by the LED bulb &
received by photoreceptors.

4. Introduction

5. History Of Li-Fi
 The technology truly began during the 1990’s in countries like
Germany, Korea, & Japan where they discovered LED’s could be
retrofitted to send information. Prof. Harald Hass continue to
wow the world with the potential to use light for communication.
Prof. Harald Hass
Univ. of Edinburg.
 Prof. Hass promoted this technology in his
2011 TED Global talk and helped start a
company to market it.
 In Oct 2011, companies and industry group
formed the Li-Fi consortium, to promote
high-speed optical wireless system.
 The first Li-Fi smartphones prototype was
presented 7-10 jan 2014 at Las Vegas

6. Present scenario
1.4 Million 5 Billion
Radio Spectrum is congested but the demand for
wireless data double each year. Everything, it seems
want to use wireless but the capacity is drying up.

7. Issues Regarding Radio spectrum

8.  Capacity
• Cost & Expensive .
• Less bandwidth compare to other spectrum.
• Insufficient for increasing data .
 Efficiency
• Millions of bases stations consume huge amount of energy
for
1. Transmitting the radio waves.
2. To cool the base stations cabin.
• 5% efficiency.
 Availability
• Availability within the range of Bases stations.
• Limited Availability.
• Unavailability in aircrafts.
 Security
• Less Secure ( Harmful for human ).

9. Electromagnetic spectrum

10. Why Only Vlc
 Gama rays can’t be used as they could be dangerous .
 X-rays have similar health issues.
 Ultraviolet light is good for place withought people, but otherwise
dangerous for human body
 Infrared, due to eyes safety regulation, can only used with lower
power
Radio
Waves
Infrared
Rays
Visible
Rays
Ultraviolet
Rays
X-Rays Gama
Rays
Hence we left with the only the visible-light spectrum

11. How Li-Fi Works ?
 The Li-Fi works on the principle of VLC (Visible Light Communication).
 The data from the internet & the local network is used to modulate the intensity
of LED light source in a way undetectable to the human eyes. The photo detector
picks the signal, which convert back into a data stream and sent to the client.
 Operation is very simple, if the LED is ON, transmitting a digital 1, if it’s OFF,
then transmitting 0. The LEDs can be switched on and off very quickly, which
gives nice opportunities for transmitting data. Hence all that us required some
LEDs and a controller that code data into those LEDs.
 Flicker depending upon the data we want to encode.
LEDs bulb

12. How Li-Fi Works ?
 An overhead lamp fitted with an LED with signal processing technology (Above)
stream data embedded in its beam at ultra-high speeds to photo detector. A receiver
dongle then convert the tiny changes in amplitude into an electrical signal, which
may then convert back into a data stream and transmitted to a computer or mobiles
device.

13. How Li-Fi Works ?

14. Real time usage of li-fi

15. Comparison between li-fi and wi-fi
 Li-Fi can be thought of as a light-based Wi-Fi. that is, it use light
instead of radio waves to transmit information.
 Instead of Wi-Fi modems, Li-Fi would use of transceiver-fitted LED
lamp that can light a room as well as transmit and receive
information.
 Wi-Fi is great for general wireless coverage within buildings, and Li-
Fi is ideal for high density wireless data coverage in confined area.
 So two technological can be considered complimentary.

16. Advantage of li-fi
 Li-Fi can solve problem related to the insufficiency of radio frequency
bandwidth because this technology uses visible light spectrum.
 High data transmission rate up to 10Gbps can be achieved.
 Since light can not penetrate walls, it provides privacy and security that Wi-Fi can not.
 Li-Fi has low implementation and maintenance cost.
 Li-fi has no harmful effect for humans body and environment .
 Li-Fi has no wastage of signals .

17. Disadvantage of li-fi
 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 system.
 Interference from external light source like sunlight , normal bulb
opaque material.

18. Applications of li-fi
 Li-Fi technology is still in its infancy. However some areas where it seems
perfectly applicable are :
 potential application of Li-Fi
 Traffics light : traffic light can
communicate to the cars and with each other.
Cars have LED
based headlights, LED-based cack lights, and
cars can communicate with each other
and
prevent accidents in by exchanging
information.
 Intrinsically safe environment :
visible light is more safe than RF, hence
it
can be used in place where RF can’t
be
used such as petrochemical plants.

19.  potential application of Li-Fi
 Hospitals :
In few medical equipment like
MRI scan.
 Airlines :
whenever we travel through airways
we
face the problem in communication
media due to less RF. to overcome this
on radioways, Li-Fi is introduced.
 On Ocean beds :
Li-Fi can even work underwater where
Wi-Fi fails completely.

20.  potential application of Li-Fi
 Street lamps (As free Access Points) :
 There are millions of street lamps deployed around the world..

21. conclusion
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 hotspot to transmit wireless data.

22. Li-fi Technology