we are the 6th sem Information Science and Engineering students from Sri Venkateshwara College of Engineering Bangalore

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Ms. AREEFA BANU
INFORMATION SCIENCE AND
ENGINNEERING
SRI VENKATESHWARA COLLEGE OF
ENGINEERING
LI-FI TECHNOLOGY
PRESENTED BY
Mr. SHANTOSH RAJ
INFORMATION SCIENCE AND
ENGINEERING
SRI VENKATESHWARA
COLLEGE OF ENGINEERING
And
UNDER GUIDANCE OF
Mrs.Pankaja R
Assistant professor, Department of CSE
Sri Venkateshwara College Of Engineering

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• Introduction
• What is Wi-Fi ???
• Issues regarding Wi-Fi (Radio Spectrum)
• What is Li-Fi???
• Principle of Li-Fi Technology
• Visible Light Communication
• Construction and Working of Li-Fi
• Comparison between Wi-Fi and Li-Fi
• Future Applications of Li-Fi
• Advantages and Disadvantages
• Conclusion
• References
CONTENTS

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WHAT IS Wi-Fi??
WHAT IS
Wi-Fi ???

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ISSUES REGARDING WI-FI
Capacity Availability Efficiency Security

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LI-FI

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Li-Fi (Light Fidelity)
• Li-Fi (Light Fidelity )can be thought of as a light-based Wi-Fi.
• Technology uses The Visible Spectrum
• The term was first used by Harald Haas in his TED Global talk
on Visible Light Communication in 2011
• In October 2011 a number of companies and industry groups
formed the Li-Fi consortium, to promote high-speed optical
wireless systems.
• Researchers at the Heinrich Hertz Institute in Berlin,
Germany, have reached data rates of over 500 megabytes per
second using a standard white-light LED.

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LI-FI ENVIRONMENT

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PRINCIPLE OF LI-FI
TECHNOLOGY
• The heart of this technology is a new generation high
brightness led’s.
• Visible Light Communication.
• These led’s varies in intensity (that is gets on and off) so
fast that a human eye cannot detect it.
• If led is on , then we transmit a digital signal 1,and if the
led is off , then we transmit a digital signal 0.
• A controller is connected at the back side of these led
bulbs to code data to these led’s.

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If led is on , then we transmit a digital signal 1,
and if the led is off , then we transmit a digital signal 0.

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VISIBLE LIGHT COMMUNICATION
ж Li-Fi is a faster and cheaper version of Wi-
Fi, which is based on visible light
communication (VLC).
ж The visible light communication is a data
communication technique using visible light
between 400 THz and 800 THz as an optical
carrier for data transmission.

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WHY VLC???

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ж Gama rays,X-rays,Ultraviolet rays are harmful for the human
body.
ж Infrared rays are also dangerous, due to eye safety
regulation, and can only be used with low power.
ж Radio waves are expensive and they are less secure.
ж Hence we are left with only the VISIBLE - LIGHT
SPECTRUM which is not harmful for humans .
Radio
Waves
Infrared
Rays
Visible
Rays
Ultraviolet
Rays
X- Rays
Gama
Rays

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CONSTRUCTION AND WORKING OF Li-Fi

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CONSTRUCTION and WORKING OF Li-Fi (conti..)
ж Li-Fi is implemented using white LED light bulbs at
downlink transmitter.
ж By fast variations of the current, optical output can be made
to vary at extremely high speeds.
ж An overhead lamp fitted with an LED with signal processing
technology streams data embedded in its beam at ultra high
speeds to the photodiodes.
ж A receiver dongle then converts the tiny changes in
amplitude into an electrical signal, which is then converted
back into a data stream & transmitted to a computer or
mobile device.

16. Sl.No Parameters Light Fidelity Wireless Fidelity
1 Speed for data transfer Faster transfer speed (>1 Gbps) Data Transfer speed (150 Mbps)
2 Medium through which
data transfers occurs
Used Light as a carrier Used Radio spectrum
3 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.
4 Cost Cheaper than Wi-Fi because free
band
doesn’t need license and it use light.
Expensive in comparison to Li-Fi
because its uses radio spectrum.
5 Network topology Point to point Point to point
6 Operating frequency Hundreds of Tera Hz (THz) 2.4 GHz
COMPARISON BETWEEN LI-FI AND WI-FI

17. In vehicles and traffic lights, reducing accidents
and traffic congestion

19.  Hospitals

20.  Street lamps(as free access points)

21.  Petroleum and chemical industries

22. Availability Efficiency Harmless
High
Security
Ease of use Fast Data
Transfer
Low Cost

23. •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
•Interferences from external light sources like
sun , light , normal bulbs , opaque materials .

24. The possibilities are numerous and can be
explored further.
 In spite of disadvantages if this technology can
be put into practical use, every bulb can be
used something like a Wi-Fi hotspot to transmit
wireless data and we will proceed toward the
cleaner, greener, safer and brighter future.

25.  Jyoti Rani1, Prerna Chauhan2, Ritika ripathi3,1Student,
,2Student,ad ,3Assistant Professor, ECE, Dep't. " Li-Fi (Light
Fidelity)-The future technology In Wireless communication" ISSN
0973-4562 Vol.7 No.11 (2012)
 Shailander kaushik, System Analytic,Nuclear Software export Ltd,
"An overview of technical aspects for wifi networks technology "
,ISSN-2277-1956.
 Visible Light Communications Consortium,www.vlcc.net, 2008
 Sathya.T,Prof.E.Divya,Prof.S.Raja,student,assistant professor, head
of department, ECE, CTKEC,"Visible Light Communication for
Wireless Data Transmission ". Coimbatore, India Feb. 2014.
 Harald Haas "Wireless Data From Every Light bulb" TED Global
Edinburgh, July 2011.
 M.Muthamma , Assistant Professor, ECE, GCET, Hyderabad , A.P.,
India ." A survey on Transmission of data through illumination - Li-
Fi " Dec 2013.

26. Mrs.Pankaja R
Assistant Professor , Department of Computer Science
and Engineering
For guiding us throughout the
preparation of this paper
presentation
Special Thanks to