Transcript Underwater wireless communication By: k.shiva shankar Electronics and communication engineering (06J11A04A4) INTRODUCTION    wireless communication technology today has become part of our daily life, the idea.

Underwater wireless communication
By: k.shiva shankar
Electronics and communication engineering
(06J11A04A4)
INTRODUCTION
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wireless communication technology today has become part of
our daily life, the idea of wireless underwater
communications may still seem far-fetched
Although cabled submersible systems remain indispensable
but if high-speed communication link is to exists
wireless underwater communications with sensor technology
and vehicular technology
Communication channel
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The signals that are used to carry digital information
through an underwater channel are acoustic signals
An underwater acoustic channel presents a
communication system designer with many difficulties
The signal is subject to multipath propagation, which
is particularly pronounced on horizontal channels
Wave propagation
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The figures show multipath
propagation in water
In shallow water, multipath
occurs due to signal reflection
from the surface and bottom
tx
rx
c
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In deep water, it occurs due to
ray bending
tx
distance
inp.1
combiner
inp.2
data est.
forward
+
_
data out
decision
forward
inp. K
filter
coefficients
sync
.
Adaptation
feedback
training data
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Adaptive decision-feedback equalizer (DFE)
Equalizer task is to unravel the inter symbol interference
Underwater networks
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Integrated networks of
instruments, sensors, robots
and vehicles will operate
together in a variety of
underwater environments
Depending on the
application there two types
of Acoustic network
“Acoustic networks, navigation and sensing
for multiple autonomous underwater robotic
vehicles
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Centralized network, nodes
communicate through a base
station that covers one cell
In a decentralized network, nodes
communicate via peer-to-peer
To accommodate multiple users
within a selected network
topology, the communication
channel must be shared
Methods for channel sharing are
based on scheduling or on
contention
Centralized network topology
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Decentralized network
topology
Current achievements
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The modem has successfully
been deployed in a
number of trials
This modem is implemented
in a fixed-point DSP with a
floating-point co-processor
Multi-user communications
each at 1.4 kbps in 5 kHz
band
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Autonomous underwater
vehicle (AUV) is a robot that
travels underwater
Modem’s fit easily into the
AUV
Low power consumption
Very reliable for high level
throughput
Autonomous underwater vehicle
(AUV)
short distance
high bandwidth
acoustic link
base
station
platform
sea level
AUV
power, communications, oil
base
station
base
station
Application to oil-field monitoring
Applications
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Environmental monitoring to gathering of
oceanographic data
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Marine archaeology
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Search and rescue missions
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Defence
Conclusion
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The aim of this is to build a
acoustic communication as in
figure
This is not only the way for
underwater communication
By using optical waves which
offers higher throughput
(Mbps) over short distances
(up to about 100 m)
Thank you