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How does li-fi technology work
Li-Fi is a technology that uses the LIGHT EMITTING DIODES (LED) to transmit the wireless data and how to use li fi technology and future scope of lifi technology free ppt download
(Light – Fidelity)Contents
HOW LIFI IS DIFFERENT
HISTORY OF LIFI
WHY LIFI COMES
HOW LIFI WORKS
LIFI VS WIFI
▸ LiFi means “LIGHT FIDELITY”
▸ LiFi is fast and cheap optical version
▸ LiFi is a technology that uses the
LIGHT EMITTING DIODES (LED) to
transmit the data wirelessly .
▸ LiFi based on VISIBLE LIGHT
▸ VLC is a data communication medium,
which uses the visible light between
400 THz (780 nm) and 800 THz (375
nm) as optical carrier for data
transmission.How LiFi Is Different
LiFi technology is based on LEDs for the
transfer of data.
The transfer of the data can be with the help of all kind
of light i.e., Light may be Invisible, Ultraviolet or
Visible part of spectrum.
The speed of the internet is incredibly high and the
user everything in just a few minutes.History of LiFi
This technology was invented by German Physicist
“HARALD HASS”, from the university of Edinburgh, U.K.
He demonstrated it in the year 2012.
But, the technology was truly began during the 1990‟s in countries like
Germany, Korea Japan.
where they discovered LED‟s could be retrofitted to send information
UNIVERSITY OF EDINBURGH :LiFi Construction
▸ The LiFi product consists of three primary sub
▸ Emitter (including bulb)
▸ RF Driver.
▸ Power supplyFunction of Bulb Assembly
▸ At the heart of LIFI is the bulb subassembly
where a sealed bulb is embedded in a
▸ The dielectric material serves two purposes:
▸ 1) waveguide
▸ 2) Electric fieldRF Drive
▸ Power amplifier (PA)
assembly that uses an
▸ Converts electrical energy
into RF power.
▸ The PA is designed for
ruggedness and efficiency.
▸ The RF driver also contains
controls circuit for digital
and analog lighting controls.A Typical LiFi ScenarioWhy LiFi comes
Due to Issues regarding with Radio frequency Spectrum
SecurityRadio Spectrum Issues
• Less secure(passes
through the walls)
Cost and Expensive.
Less Bandwidth compared to other
Insufficient spectrum for increasing
Millions of base stations consume
huge amount of energy for
1.) Transmitting the radio waves
Available within the range of
2.) To cool the base station cabins
Limited availability. 5 Efficiency
Unavailable in aircrafts.Electromagnetic SpectrumRadio Infrared Visible Ultraviolet Gama Rays
Waves Rays Rays Rays
• Gama rays cant be used as they could be dangerous.
• Xrays have similar health issues.
• Ultraviolet light is good for place without people, but other wise
dangerous for the human body.
• Infrared, due to eye safety regulation, can only be used with low power.
• HENCE WE LEFT WITH THE ONLY THE VISIBLE LIGHT
SPECTRUM.WHAT USES CAN
RADIO WAVES FOR
COMMUNICATION THROUGH LIFI
By the use of lifi we can replace radio waves for wireless
communicationHow LiFi Works
• Procedure is very simple, if the LED is on , then your device transmit a digit
„1‟ if it is off, then your device transmit a digit „0‟.
• The LED can be switched on off very quickly, which gives nice
opportunities for transmitting data.
• Hence, all that required is some LEDS a controller that code data into those
LEDS.Comparison Between LiFi vs. WiFiFeatures of LiFi
10,000 Times more spectrum then RW.
Light boxes are already present, so infrastructure is available already and installed .
Highly efficient because LED consume less energy.
Light is present every where.
Data is present where light is present.
Light waves does not penetrate through walls.
Hence they can not be INTERCEPTED.Advantages of LiFi
• It is impossible to achieve more than 10Gbps,
theoretically allowing a highdefinition film
to be downloaded in 30 sec.
• Mostly powered by LEDs so it is cost efficient
Transmission of data is fast and easy.Disadvantages of LiFi
Presence of light is
There should be line of sight
Works better with fluorescent
light and LEDs but very low
efficiency with bulbs.Applications of LiFi
environment Future Scope
• This research report categories the global VLC technology market
based on component, application and geography.
• Lifi uses light emitting diodes (LEDs) which are rapidly gaining in
popularity for standards light bulbs and other domestic and commercial
purposes . They are expected to be ubiquitous in 20 years.
• Still under research :
• What will be effect of interference from external light sources like sun
light and normal bulbs
• What about the limited bandwidth of existing copper cable used for
electrical connection.Future Scope
• Where do the connections uplink, how serious are the
modifications needed to the power grid.
• How will other devices React if you Inject a high frequency in to
• 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 WiFi hotspots to transmit wireless data.Thanks
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