underwater wireless giet

8/4/2019 Underwater Wireless GIET

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Underwater wirelesscommunication

By: k.shiva shankar

Electronics and communication engineering

(06J11A04A4)


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INTRODUCTION

wireless communication technology today hasbecome part of our daily life, the idea of wirelessunderwater communications may still seem far-fetched

Although cabled submersible systems remainindispensable but if high-speed communicationlink is to exists

wireless underwater communications with sensortechnology and vehicular technology


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Communication channel

The signals that are used to carry digitalinformation through an underwaterchannel are acoustic signals

An underwater acoustic channel presentsa communication system designer withmany difficulties

The signal is subject to multipathpropagation, which is particularly

pronounced on horizontal channels


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Wave propagation

The figures showmultipath propagationin water

In shallow water,multipath occurs due to

signal reflection fromthe surface and bottom

In deep water, it occursdue to ray bending

tx

distancec

tx rx


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inp. K

com-

biner forward

forward

+ _ decision

feedback

Adaptation

inp.1

inp.2 data out

sync.

filter

coefficients

training data

data est.

Adaptive decision-feedback equalizer (DFE)

Equalizer task is to unravel the inter symbolinterference


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Underwater networks

Integrated networks ofinstruments, sensors,

robots and vehicleswill operate togetherin a variety ofunderwater

environments Depending on the

application there two

types of Acousticnetwork

Acoustic networks, navigation and sensing

for multiple autonomous underwater robotic

vehicles


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Centralized networktopology

Centralized network, nodescommunicate through abase station that coversone cell

In a decentralized network,nodes communicate viapeer-to-peer

To accommodate multipleusers within a selectednetwork topology, thecommunication channelmust be shared

Methods for channel

Decentralized networktopology


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Current achievements

The modem hassuccessfully beendeployed in a number

of trials This modem is

implemented in afixed-point DSP with a

floating-point co-processor

Multi-usercommunications eachat 1.4 kbps in 5 kHz


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Autonomous underwatervehicle (AUV)

Autonomousunderwater vehicle(AUV) is a robot that

travels underwater Modems fit easily into

the AUV

Low power

consumption Very reliable for high

level throughput


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Application to oil-field

short distance

high bandwidth

acoustic link

platform

base

station

power, communications, oil

AUV

sea level

base

station

base

station


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Applications

Environmental monitoring to gathering ofoceanographic data

Marine archaeology

Search and rescue missions

Defence


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Conclusion

The aim of this is tobuild a acousticcommunication as in

figure

This is not only the wayfor underwater

communication

By using optical waves

which offers higher


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Thank you

underwater wireless giet

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