Imagine
only needing to hover under a street lamp to get public internet access, or
downloading a movie from the lamp on your desk. There's a new technology on the
block which could, quite literally as well as metaphorically, 'throw light on'
how to meet the ever-increasing demand for high-speed wireless connectivity.
Radio waves are replaced by light waves in a new method of data transmission
which is being called Li-Fi.
Light
Fidelity (Li-Fi): a method of transmitting data wirelessly using LED (=
light-emitting diode) technology
Definition
- What does LIFI mean?
Li-fi
is an innovative idea in IT, one that aims at eventually replacing radio
frequency wireless signals with those that come from light sources. This type
of technology is still being developed, and may have the potential to introduce
vastly improved wireless services.
Techopedia
explains LIFI
New
reports from the BBC show that Chinese researchers are developing a microchip
light bulb that could enable up to 150 Mb per second of data transfer. This
idea, also known as visible light communications or VLC, is just being
pioneered in various applications. Scientists point out that visible light spectrums
are part of the greater electromagnetic spectrum, and that this kind of
application of light energy could help to unlock the puzzle of how to offer
enough frequency capacity for a seemingly exponential demand.
Benefits
of LiFi:
·
Higher speeds than Wi-Fi.
·
10000 times the frequency spectrum of
radio.
·
More secure because data cannot be
intercepted without a clear line of sight.
·
Prevents piggybacking.
·
Eliminates neighboring network
interference.
·
Unimpeded by radio interference.
·
Does not create interference in
sensitive electronics, making it better for use in environments like hospitals
and aircraft.
By
using LiFi in all the lights in and around a building, the technology could
enable greater area of coverage than a single WiFi router. Drawbacks to the
technology include the need for a clear line of sight, difficulties with
mobility and the requirement that lights stay on for operation.
Li-Fi
Wireless Communications Projects
Optical
Multiuser MIMO
Description:
In this project we study optical multiuser MIMO techniques in an optical
attocell network. In particular, we exploit the properties that intensity
modulation (IM) does not suffer from multipath fading, and that LEDs offer very
directional beams. This work will contribute novel algorithms for networked,
multiuser Li-Fi systems.
Interference
Management in Optical Attocell Networks
Description:
This project addresses the issue of co-channel interference in an optical
attocell network. The project will develop novel interference cancellation
techniques which are tailored to Li-Fi signals. Moreover, the project will
study cell cooperation techniques as well as potential interference avoidance
techniques taking into account the particular signal propagation
characteristics in the visible light and infrared spectrum.
The
Internet-of-Things enabled by Li-Fi
Description:
Li-Fi uses direct modulation without the need for intermediate frequencies
(super-heterodyning) in RF systems. Moreover, it uses inexpensive optical
components such as off-the-shelf LEDs and photodetectors. It is, thus, possible
to create small, low-complex transceiver units that enable any LED light to act
as a high speed data transmitter. Similarly, various low-complexity photodector
solutions will be studied. Finally, this work will investigate novel Li-Fi
transceiver concepts and study Internet-of-Things and sensor network scenarios
based on the proposed transceiver technology.
Li-Fi
Spatial Modulation
Description:
Spatial modulation is a new digital modulation and MIMO technique which enables
highly energy-efficient transmitters as it only requires a single transmitter
chain. We explore spatial modulation for Li-Fi transmitters and investigate how
SM can be used to support dimming. In addition, we study the impact of various
optical components such as polarisers and lenses on the performance of optical
spatial modulation.
Novel
Digital Modulation Techniques for Li-Fi
Description:
Li-Fi uses intensity modulation and direct detection. Therefore, the signals
must be strictly real valued and positive. These constraints pose limitation on
digital modulation techniques. These limitations result in spectrum-efficiency
or power-efficiency losses. This project investigates novel digital modulation
techniques for Li-Fi that help overcome these limitations. The project will
initially compare state-of-the-art techniques such as multicarrier transmission
techniques such as orthogonal frequency division multiplexing (OFDM),
pulse-amplitude modulation (PAM) and carrier-less amplitude modulation (CAP).
Self-powered
Li-Fi
Description:
In this project we investigate energy harvesting concepts for Li-Fi systems in
combination with energy-efficient transceiver technologies. This requires
energy-efficient digital modulation techniques and low computational complexity
algorithms. Therefore, investigations of new MAC and synchronisation techniques
as well as novel circuit designs are all within the scope of this project. The
project primarily targets sensor network applications.
Further
information on the Li-Fi research work can be found on Professor Harald Haas's
website and blog.
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