Li-fi Technology || World's fastest Internet Speed
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Transcript of Li-fi Technology || World's fastest Internet Speed
Introduction History Technology Present Scenario Radio spectrum Issues of radio spectrum Electromagnetic spectrum Why VLC only Light-fidelity Working process How it works Comparison between WI-FI & LI-FI Applications of Li-Fi Limitations or Challenges Conclusion
Content
Light Fidelity (Li-Fi) is a bidirectional, high speed and fully
networked wireless communication technology similar to Wi-Fi.
The term was coined by Harald Haas and is a form of visible light
communication and a subset of optical wireless
communications (OWC) and could be a complement to RF
communication (Wi-Fi or Cellular network), or even a replacement
in contexts of data broadcasting. It is so far measured to be
about 100 times faster than some Wi-Fi implementations,
reaching speeds of 224 gigabits per second.
It is wireless and uses visible light communication or infra-red
and near ultraviolet (instead of radio frequency waves) spectrum,
part of optical wireless communications technology, which carries
much more information, and has been proposed as a solution to
the RF-bandwidth limitations.
Introduction
Harald Haas, who teaches at the University of Edinburgh in the UK, coined the term "Li-Fi" at his TED Global Talk where he introduced the idea of "Wireless data from every light". He is Chair of Mobile Communications at the University of Edinburgh and co-founder of pure Li-Fi.
The general term visible light communication (VLC), whose history dates back to the 1880s, includes any use of the visible light portion of the electromagnetic spectrum to transmit information. The D-Light project at Edinburgh's Institute for Digital Communications was funded from January 2010 to January 2012. Haas promoted this technology in his 2011 TED Global talk and helped start a company to market it. Pure Li-Fi, formerly pure VLC, is an original equipment manufacturer (OEM) firm set up to commercialize Li-Fi products for integration with existing LED-lighting systems.
In October 2011, companies and industry groups formed the Li-Fi Consortium, to promote high-speed optical wireless systems and to overcome the limited amount of radio-based wireless spectrum available by exploiting a completely different part of the electromagnetic spectrum.
A number of companies offer uni-directional VLC products, which is not the same as Li-Fi - a term defined by the IEEE 802.15.7 standardization committee.
VLC technology was exhibited in 2012 using Li-Fi. By August 2013, data rates of over 1.6 Gbit/s were demonstrated over a single colour LED. In September 2013, a press release said that Li-Fi, or VLC systems in general, do not require line-of-sight conditions. In October 2013, it was reported Chinese manufacturers were working on Li-Fi development kits.
In April 2014, the Russian company Stins Coman announced the development of a Li-Fi wireless local network called Beam Caster. Their current module transfers data at 1.25 gigabytes per second but they foresee boosting speeds up to 5 GB/second in the near future. In 2014 a new record was established by Sisoft (a Mexican company) that was able to transfer data at speeds of up to 10 GBPS across a light spectrum emitted by LED lamps.
History of Li-Fi
Visible light communications (VLC) works by switching the current to the LEDs off and on at a very high rate, too quick to be noticed by the human eye. Although Li-Fi LEDs would have to be kept on to transmit data, they could be dimmed to below human visibility while still emitting enough light to carry data.
Technology
Radio Spectrum is congested but the demand for wireless data double each year. Every thing, it seems want to use wireless data but the capacity is drying up.
Present Scenario
1.4 Million Base Stations
5 Billion
Radio waves Cost and Expensive Less Bandwidth compared to other spectrums Insufficient spectrum for increasing data
Radio Spectrum Issues Capacity
Efficiency Millions of base stations consume huge amount of
energy for 1. Transmitting the radio waves2. To cool the base station cabins
5% Efficiency
Less secure(passes through the walls)
Radio Spectrum Issues
Availability Available within the range of Base stations Limited availability Unavailable in aircrafts
Security
Gama rays cant be used as they could be dangerous. X-rays 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.
Why only VLCRadio
Waves Infrared
RaysVisible Rays
Ultraviolet Rays X- Rays
Gama Rays
Operational procedure is very simple, if the led is on, you transmit a
digital 1, if its off you transmit a 0. The LEDs can be switched on and
off very quickly, which gives nice opportunities for transmitting data.
Hence all that us required is some LEDs and a controller that code data
into those LEDs. We have to just vary the rate at which the LED’s .
Flicker depending upon the data we want to encode .
Thus every light source will works as a hub for data transmission .
Working Process
On one end all the data on the internet will be streamed to a
lamp driver when the led is turned on the microchip converts the
digital data in form of light .
A light sensitive device (photo detector) receives the signal and
converts it back into original data. This method of using rapid
pulses of light to transmit information wirelessly is technically
referred as Visible Light Communication .
How Li-Fi Works ?
Li-Fi can be thought of as a light-based Wi-Fi. That is, it uses light
instead of radio waves to transmit information.
Instead of Wi-Fi modems, Li-Fi would use trans receiver-fitted LED lamps
that can light a room as well as transmit and receive information.
WI-FI is great for general wireless coverage within buildings, and Li-Fi is
ideal for high density wireless data coverage in confined area and for
relieving radio interference issues .
So the two technologies can be considered complimentary.
Comparison between Li-Fi and Wi-Fi
Li Fi technology is still in its infancy .However some areas where it seems perfectly applicable are:-
Application Areas
Traffic Lights :
Traffic lights can
communicate to the car and
with each other. Cars have
LED-based headlights, LED-
based back lights, and cars
can communicate with each
other and prevent accidents
in by exchanging
information.
Visible Light is more safe than RF, hence it can be used in places where RF can't be used such as petrochemical plants .
Application of Li-Fi Intrinsically Safe Environment :
Whenever we travel through airways we face the problem in communication media, because the whole airways communication are performed on the basis of radio waves. To overcome this drawback on radio ways, li-fi is introduced.
Application of Li-Fi
Li-Fi can even work underwater where Wi-Fi fails completely, thereby throwing open endless opportunities for military/navigation operations.
Application of Li-Fi On Ocean Beds :
There are millions of street lamps deployed around the world.
Each of these street lamps could be a free access point.
Application Street Lamps (As free Access
Points) :
Light can't pass through objects.
Interferences from external light sources like sun light, normal
bulbs, and opaque materials in the path of transmission will cause
interruption in the communication.
Li-Fi requires line of sight.
A major challenge facing Li-Fi is how the receiving device will
transmit back to transmitter.
Limitations or Challenges
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 Wi-Fi hotspots to transmit wireless data.
Conclusion
References www.nasa.gov/science/toolbox/emspectrum1.html
http://missionscience.nasa.gov/
http://www.ted.com/talks/harald_haas_wireless_data_from_every_light_bulb
http://gimt.edu.in/clientFiles/FILE_REPO/2012/NOV/23/1353645362045/69.pdf (E-Book)
http://ids.nic.in/technical_letter/Tnl_Jan2014/LI-FI%20(Light%20Fidelity)-The%20Future
%20Technology.pdf (E-Book)
http://www.lifi.eng.ed.ac.uk/lifi-news/2016-01-07-0734/what-lifi
http://www.homepages.ed.ac.uk/hxh/Li-Fi_PAPERS/what_is_LiFi_invited_ jlt_ecoc15.pdf (E-
Book)
http://purelifi.com/
http://www.ijirae.com/volumes/Vol2/iss6/01.JNAE10083.pdf
http://newtecharticles.com/new-li-fi-technology-to-access-internet/