Under Water Acoustic Communication Channel

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  • Topic: Sonar, Speed of sound, Acoustics
  • Pages : 24 (6572 words )
  • Download(s) : 118
  • Published : February 7, 2013
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A SEMINAR REPORT

ON

UNDERWATER ACOUSTIC COMMUNICATION CHANNEL

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Submitted

By

SOWMYA.G.S

1DS06TE099

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Bachelor of Engineering (B.E.)

In

TELECOMMUNICATION ENGINEERING (TE)

DAYANANDA SAGAR COLLEGE OF ENGINEERING

CERTIFICATE
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UNDERWATER ACOUSTIC COMMUNICATION CHANNEL

Submitted

By

SOWMYA.G.S

Of the VIII semester in the year 2010 in partial fulfillment of the requirements in the awards of Bachelor of Engineering in Telecommunication.

DATE OF SUBMISSION:-

TAFF IN CHARGE HEAD OF DEPT.

Contents

Introduction…………………………………………………………………. 05

Background……………………………………………………………………..07

Underwater Acoustic Physics in the Ocean

Propagation Loss………………………………………….......13

Absorption…………………………………………………..... 13

Spreading Loss………………………………………………..14

Range, SNR…………………………………………………....14

Multipath………………………………………………………16

Communication in underwater acoustic sensor networks

Introduction…………………………………………………..18

Need for acoustic sensor networks…………………………..18

Drawbacks in the existing access control

And routing protocols………………………………………..19

UW-ASN communication architecture……………………….21

A protocol stack……………………………………………….24

Conclusion…………………………………………………………………………..26

References…………………………………………………………………………..26

List of figures

F ig.1 Energy absorption in water………………………………………………………… 11

Fig.2 Sound wave travelling down a tunnel…………………………………………. 12

Fig.3 Location of waves represented by a single ray-pat…………………….. 12

Fig.4 Multipath reflection…………………………………………………………………… 17

Fig.5 Multipath refraction…………………………………………………………………… 17

Fig.6 Sound wave spreading spherically from source…………………………… 14

Fig.7 Architecture of 2D sensor network……………………………………………….. 21

Fig.8 Architecture of 3D sensor network……………………………………………….. 23

INTRODUCTION

The need for underwater wireless communications exists in applications such as remote control in off-shore oil industry ,pollution monitoring in environmental systems, collection of scientific data recorded at ocean-bottom stations, speech transmission between divers, and mapping of the ocean floor for detection of objects, as well as for the discovery of new re-sources Wireless underwater communications can be established by transmission of acoustic waves Underwater acoustic communications are a rapidly growing growing field of research and engineering as the applications, which once were exclusively military, are extending into

commercial fields The possibility to maintain signal transmission, but eliminate physical connection of tethers, enables gathering of data from submerged instruments without human intervention, and unobstructed operation of unmanned or autonomous underwater vehicles (UUVs, AUVs)

Acoustic waves are not the only means for wireless transmission of signals under water However, radio waves that will propagate any distance through conductive sea water are the extra low frequency ones (30 Hz -300Hz)which require large antennae and high transmitter powers...
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