Powerpoint Templates Page 1 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
Powerpoint Templates Page 2 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
Powerpoint Templates Page 3 WHAT IS Wi-Fi?? WHAT IS Wi-Fi
???
Powerpoint Templates Page 7 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.
Powerpoint Templates Page 8 LI-FI ENVIRONMENT
Powerpoint Templates Page 9 PRINCIPLE OF LI-FI TECHNOLOGY The
heart of this technology is a new generation high brightness leds.
Visible Light Communication. These leds 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
leds.
Powerpoint Templates Page 10 If led is on , then we transmit a
digital signal 1, and if the led is off , then we transmit a
digital signal 0.
Powerpoint Templates Page 11 VISIBLE LIGHT COMMUNICATION Li-Fi
is a faster and cheaper version of Wi- Fi, which is based on
visible light communication (VLC). 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.
Powerpoint Templates Page 12 WHY VLC???
Powerpoint Templates Page 13 Gama rays,X-rays,Ultraviolet rays
are harmful for the human body. Infrared rays are also dangerous,
due to eye safety regulation, and can only be used with low power.
Radio waves are expensive and they are less secure. 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
Powerpoint Templates Page 14 CONSTRUCTION AND WORKING OF
Li-Fi
Powerpoint Templates Page 15 CONSTRUCTION and WORKING OF Li-Fi
(conti..) Li-Fi is implemented using white LED light bulbs at
downlink transmitter. By fast variations of the current, optical
output can be made to vary at extremely high speeds. An overhead
lamp fitted with an LED with signal processing technology streams
data embedded in its beam at ultra high speeds to the photodiodes.
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.
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 doesnt
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
In vehicles and traffic lights, reducing accidents and traffic
congestion
Hospitals
Street lamps(as free access points)
Petroleum and chemical industries
Availability Efficiency Harmless High Security Ease of use Fast
Data Transfer Low Cost
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 .
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.
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.
Mrs.Pankaja R Assistant Professor , Department of Computer
Science and Engineering For guiding us throughout the preparation
of this paper presentation Special Thanks to
