Li-Fi is the term used to label the fast
wireless communication systems, low cost, optical equivalent to Wi-Fi. The term
was first used in this context by Harald Haas in a TED conference on
communication using visible light.
The technology was shown at the Consumer
Electronics Show in 2012 using a pair of smart phones to exchange data Casio
varying the intensity of light from their screens, running a maximum distance
of ten meters.
In October 2011, a group of companies and
industry groups formed the Li-Fi Consortium to promote wireless high-speed
optical systems and overcome the limitations of the radio spectrum by exploiting
a completely different part of the electromagnetic spectrum. The consortium
believes it is possible to reach speeds of more than 10 Gbps, theoretically
allowing a high definition movie to be downloaded in 30 seconds.
Li-Fi has the advantage of not causing
interference with other systems and can be used in sensitive areas like the
inside of an airplane. However, the light waves used can not penetrate walls.
Li-Fi is the popular name of a technology of
optical communication that takes investigated over 100 years and it is to
transmit data at frequencies between 400 and 800 THz (ie, in the visible
spectrum of human) in open space.
It claims to be able to transmit information
with elements of conventional lighting (LED bulbs) while staying lights, and
adding only one few cheap and easy to manufacture with current bulbs elements.
Basically a modulator in the transmitting
side that turn off and on the light source very quickly (so imperceptible to
humans), thus creating binary zeros and ones, and a photodiode in the receiver
part (eg in the mobile is required ) that collects light changes and go back to
the electrical domain.
Early versions used fluorescent lamps with
which few Kbps speeds were reached. Later they began to use LEDs, capable of
turning off and on faster, more power, multiplying the final velocities. But it
was not until 2011 Professor Harald Haas of the University of Edinburgh showed
the first device he called Li-Fi transmitting at 10 Mbps, as we begin to see
the true potential of the technology.
What you can use these communications Li-Fi?
Well mainly to transmit high-speed data while room lights. Li-Fi has numerous
advantages. For starters, not saturate the portion of spectrum currently used
by other systems such as WiFi in its different versions, and using visible
light.
The information comes from the beam of light
from the LEDs, so that we can either create a sparse bundle to provide a wide
coverage or a very thin beam illuminating small areas and transmit data more
directional way. This allows greater control over who are arriving data at all
times and allows networks safer short range.
It can also be used to transmit large amounts
of data between computers or media devices. For example, we can send a video of
the phone to a TV quickly or copy it to a network hard drive only target phone
to the TV or the hard disk for a few seconds, as we do with the remote control
to change channels (which incidentally also uses a variant of "Li-Fi"
based on infrared).
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