LiFi

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Hamdard Institute of Engineering Sciences
Technology

• Presented By
• Rasim Izhar Ali BECS/S13/0109
• Murad Ali Jamali BECS/S13/0106

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Table of Contents

• What is Li-fi?
• Introduction
• History
• Present Scenario
• Issues of Using Radio Spectrum
• Who can resolve this issue?
• Principle of Li-Fi
• Why Li-Fi use VLC?
• Li-Fi Vs Wi-Fi
• Applications Of Li-Fi.
• Merits And Demerits
• Conclusion

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What is Li-fi(LIGHT FIDELITY)?

• Light based Wi-Fi
• Light is used instead of radio waves to transmit
  information.
• Transceiver fitted LED lamps acts like Wi-Fi
  modems.
• LED lamps can light a room as well as
  transmit-receive information.
• Sending data through a LED light bulb that
  varies in intensity faster than human eye can
  follow.

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History

• Prof. Harald Haas, from university of Edinburgh
  in the UK is the founder of Lifi.
• On 20th July 2011 he used a table lamp with an
  LED bulb to transmit a video of blooming flowers
  that was then projected onto a screen behind him.
  During the event he periodically blocked the
  light from lamp to prove that the lamp was indeed
  the source of incoming data.

• Professor Harald Haas

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Present Scenario

• 1.4 Million Base Stations

• 5 Billion Mobile Stations

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Present Scenario

• Radio Spectrum is congested but the demand for
  wireless data double each other.
• Data in the form of tera bytes travel every week
  or month.
• Every one want to use wireless data but the
  capacity is drying up resulting in different
  issues.
• So, what can carry this excess demand in future

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Issues Of Using Radio Spectrum
Spectrum is 10,000 times greater than that of
radio frequency.
Light waves available everywhere.
Highly efficient since LED consumes less energy.
Cannot penetrate through walls. Hence data can be
secured.
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Who can resolve this issue?
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Principle of Li-Fi

• When LED is ON ,we transmit a digital signal 1
  and if the LED is OFF , we transmit a digital
  signal 0.

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Working Principle of Li-Fi
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Why Li-fi use Visible Light Communication?
Radio Waves
Infrared Rays
Visible Rays
Ultraviolet Rays
X-Rays
Gamma Rays

• 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.
• Therefore, only Visible rays or visible light
  spectrum is left which is not harmful for humans.

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Characteristics Wireless Fidelity Light Fidelity
Range 100 meters Based on LED
Power Consumption Medium Low
Cost Expensive in comparison with LiFi because it uses Radio Spectrum Cheaper than Wifi because free band doesnt need license and uses light
Security Moderate Secured Highly Secured
Data transfer rate Within MBPS Greater than GBPS
Medium Through which data transfer Use radio Spectrum Use light as a carrier
Spectrum Range Radio Spectrum Range is less than visible light spectrum Visible light spectrum is 10,000 times broader than Radio spectrum range
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Applications of Li-Fi

• Traffic Scenario-
• Lifi can be used to communicate with the LEDs
  of cars.
• This might prevent accidents by exchanging
  information when the vehicles are too close.
• Using Lifi, street lights can be used to send
  information about the road condition of the car.

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Home And Small Offices

• In home and small offices, Li-fi can be used to
  communicate with the devices such as
• ? Laptops
• ? Internet access
• ? HD Video Streaming
• ? Printer

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Street Lamps Ocean Beds

• An Ocean Beds
• Li-Fi can even work under water where wifi
  fails.
• Communication between Naval becomes easy.

• Street Lamps
• There are millions of Lamps deployed around the
  world.
• Each of these street lamps could be a free
  access point.

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Merits Demerits

• Merits

• Demerits

• Data rate greater than 10Gbps theoretically
  allowing HD film to be downloaded in 30 seconds.
• Can be used everywhere even in RF areas, since
  light waves will not interfere with radio waves.
• As light waves cannot penetrate through walls,
  hence data cannot be intercepted which results in
  providing secured communication
• Mostly LED light bulbs are used which consumes
  less energy. Hence cost efficient.

• A major challenge of Li-Fi is how the receiving
  device will transmit back to receiver.
• Data transmission can be easily blocked by any
  object placed in front of LED source.
• Interferences from external light source like
  sunlight, in the path of transmission can cause
  interruption in the communication.

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Conclusion

• Researchers are developing a micron size LEDs.
• 1000 micron sized LED can fit into an area
  required by 1sq.mm large single LED.
• A 1sq.mm sized array of micron sized LEDs could
  therefore communicate 1000x1000(i.e.) million
  times as much information as a single 1sq.mm LED.
• Thus ,if Li-Fi technology can be put into
  practical use, every bulb can be used as an
  alternative to Wi-Fi hotspot.

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Thank You
THANK YOU