Li fi technology ppt
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Powerpoint Templates Page 1 PRESENTED BY SURA TEJA, 14281A0456 ELECTRONICS AND COMMUNICATIONENGINEERING
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Transcript of Li fi technology ppt
Powerpoint Templates Page 1
PRESENTED BY
SURA TEJA, 14281A0456ELECTRONICS AND
COMMUNICATIONENGINEERING
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
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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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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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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 .
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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.
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 whichdata transfers occurs
Used Light as a carrier Used Radio spectrum
3 Spectrum Range Visible light spectrum has 10,000 timebroad spectrum in comparison to radio frequency
Radio frequency spectrum range isless than visible light spectrum.
4 Cost Cheaper than Wi-Fi because free banddoesn’t need license and it use light.
Expensive in comparison to Li-Fibecause 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
•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.
Websites: 1:
http://timesofindia.indiatimes.com/home/science/Now-just-light-a-bulb-to- switch-on-your-broadband/article show/9713554.cms
2: http://oledcomm.com/lifi.html 3: http://en.wikipedia.org/wiki/Li-Fi 4: http://slideshare.com/li-fitech.html
