Download Optical wireless communication (OWC) is ... recent advances in visible-light receiver/transmitter technology and popularized by

Optical wireless communication (OWC) is a breakthrough technology sparked by
recent advances in visible-light receiver/transmitter technology and popularized by
the prospect of dual-use for indoor lighting. It is defined as any system where a
modulated light beam, whether from a laser diode or an LED, is propagated
through an open environment to obtain broadband communication.
This poster showcases research by the
Communication Systems group at the School of
Engineering in the University of Warwick. The
focus is applications of optical wireless
communications, from deep oceans to aviation,
including indoor, outdoor and vehicular uses.
Advantages over traditional communications:
• significantly higher data rates;
• licence-free frequency spectrum;
• ability to communicate in areas that restrict
radio-frequency communications;
• more energy efficient communication.
Underwater OWC has applications in ocean
mapping, environmental monitoring and defence.
Research at Warwick includes:
• underwater optical sensor networks;
• non-line-of-sight underwater links
• long range underwater links (>100m);
• hybrid underwater/acoustic systems.
Optical communications in free space undergo
scintillation and turbulence due to changes in
weather conditions. A genetic algorithm has been
developed which finds the ideal optical parameters
for a given set of conditions, where:
• the weather condition is described by four
parameters
(attenuation,
fog,
rainfall,
scintillation);
• system condition is described by ten parameters
(transmitter/receiver aperture size, beam
divergence, transmitted power, wavelength,
range, bitrate, receiver responsivity, bandwidth
and the photoreceiver hardware
Significant results:
• multiple Monte Carlo channel simulations;
• multi-hop experimental protocol testing for
sensor nodes;
• ideal wavelength selection algorithm based on
chlorophyll surface level and depth;
• estimation of refractive displacement when light
is propagated through seawater with a
refractive gradient.
Fig 1: received power from a single centrally located LED
OWC has several uses within vehicular technology.
Our research includes:
• high-bandwidth multimedia systems within the
vehicle (fig 1);
• replacing electrical or optical wires within the
chassis to improve crash safety;
• between vehicles to assist control.
The algorithm can be used to optimize any of these
parameters based on the other fixed parameters.
OWC has higher bandwidth, better security and
improved energy efficiency over indoor radiofrequency communications. We have researched:
• dynamic multi-spot transmission algorithms to
adapt to their environment;
• a new low-noise receiver, the photo-parametric
amplifier, where a photodetector is pumped at
microwave frequencies and photodetection
and parametric amplification are achieved
simultaneously.
attenuation (m-1)
For each application of optical wireless, we
characterize the channel and use it to find
optimized transmitter and receiver optics.
1
0.8
0.6
0.4
0.2
0
0
700
-50
600
-100
depth (m)
500
400 wavelength (nm)
-150
-200
-250
Fig 2: attenuation coefficient with depth and wavelength
Optical wireless communications will continue to
grow in popularity as users require higher and
higher wireless bandwidths. The technology is
planned to be included within 5G mobile wireless
and the architecture for including this technology
within homes is slowly being implemented as more
use LED lighting.
Laura Johnson
contact details
and portfolio
References
and further
reading
Communication
Systems group
research portfolio