02-07-2013, 03:17 PM
Li-Fi (Light Fidelity)-The future technology In Wireless communication
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Abstract:
Whether you’re usig wireless internet in a coffee shop,
stealing it from the guy next door, or competing for bandwidth
at a conference, you have probably gotten frustrated at the
slow speeds you face when more than one device is tapped
into the network. As more and more people and their many
devices access wireless internet, clogged airwaves are going to
make it. One germen phycist.Harald Haas has come up with a
solution he calls “data through illumination” –taking the fibber
out of fiber optic by sending data through an LED light bulb
that varies in intensity faster than the human eye can follow.
It’s the same idea band behind infrared remote controls but far
more powerful. Haas says his invention, which he calls DLIGHT,
can produce data rates faster than 10 megabits per
second, which is speedier than your average broadband
connection. He envisions a future where data for laptops,
smart phones, and tablets is transmitted through the light in a
room. And security would be snap – if you can’t see the light,
you can’t access the data.
INTRODUCTION
LiFi is transmission of data through illumination by taking the
fiber out of fiber optics by sending data through a LED light
bulb that varies in intensity faster than the human eye can
follow.Li-Fi is the term some have used to label the fast and
cheap wireless-communication system, which is the optical
version of Wi-Fi. The term was first used in this context by
Harald Haas in his TED Global talk on Visible Light
Communication. “At the heart of this technology is a new
generation of high brightness light-emitting diodes”, says
Harald Haas from the University of Edinburgh, UK,”Very
simply, if the LED is on, you transmit a digital 1, if it’s off
you transmit a 0,”Haas says, “They can be switched on and off
very quickly, which gives nice opportunities for transmitted
data.”It is possible to encode data in the light by varying the
rate at which the LEDs flicker on and off to give different
strings of 1s and 0s.The LED intensity is modulated so rapidly
that human eye cannot notice, so the output appears constant.
More sophisticated techniques could dramatically increase
VLC data rate.
WORKING TECHNOLOGY
This brilliant idea was first showcased by Harald Haas from
University of Edinburgh, UK, in his TED Global talk on VLC.
He explained,” Very simple, if the LED is on, you transmit a
digital 1, if it’s off you transmit a 0. The LEDs can be
switched on and off very quickly, which gives nice
opportunities for transmitting data.” So what you require at all
are 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.
COMPARISION BETWEEN Li-Fi & Wi-Fi
LI-FI is a term of one used to describe visible light
communication technology applied to high speed wireless
communication. It acquired this name due to the similarity to
WI-FI, only using light instead of radio.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.
How it is different?
Li-Fi technology is based on LEDs for the transfer of data.
The transfer of the data can be with the help of all kinds of
light, no matter the part of the spectrum that they belong. That
is, the light can belong to the invisible, ultraviolet or the
visible part of the spectrum. Also, the speed of the internet is
incredibly high and you can download movies, games, music
etc in just a few minutes with the help of this technology.
Also, the technology removes limitations that have been put
on the user by the Wi-Fi. You no more need to be in a region
that is Wi-Fi enabled to have access to the internet. You can
simply stand under any form of light and surf the internet as
the connection is made in case of any light presence. There
cannot be anything better than this technology.
Smarter Power Plants
Wi-Fi and many other radiation types are bad for sensitive
areas. Like those surrounding power plants. But power plants
need fast, inter-connected data systems to monitor things like
demand, grid integrity and (in nuclear plants) core
temperature. The savings from proper monitoring at a single
power plant can add up to hundreds of thousands of dollars.
Li-Fi could offer safe, abundant connectivity for all areas of
these sensitive locations. Not only would this save money
related to currently implemented solutions, but the draw on a
power plant’s own reserves could be lessened if they haven’t
yet converted to LED lighting
Undersea Awesomeness
Underwater ROVs, those favourite toys of treasure seekers
and James Cameron, operate from large cables that supply
their power and allow them to receive signals from their pilots
above. ROVs work great, except when the tether isn’t long
enough to explore an area, or when it gets stuck on something.
If their wires were cut and replaced with light — say from a
submerged, high-powered lamp — then they would be much
freer to explore. They could also use their headlamps to
communicate with each other, processing data autonomously
and referring findings periodically back to the surface, all the
while obtaining their next batch of orders.
CONCLUSION
The possibilities are numerous and can be explored further. If
his 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. The concept of Li-Fi is currently attracting a
great deal of interest, not least because it may offer a genuine
and very efficient alternative to radio-based wireless. As a
growing number of people and their many devices access
wireless internet, the airwaves are becoming increasingly
clogged, making it more and more difficult to get a reliable,
high-speed signal. This may solve issues such as the shortage
of radio-frequency bandwidth and also allow internet where
traditional radio based wireless isn’t allowed such as aircraft
or hospitals. One of the shortcomings however is that it only
work in direct line of sight.