This document discusses underwater wireless communication systems. It begins with an introduction to wireless communication and how acoustic waves are used instead of radio waves underwater. The history of underwater acoustics is then outlined, dating back to the 15th century. The document defines underwater wireless communication and discusses the necessity of such systems due to limitations of wired systems. It describes the technology used, including acoustic modems and sensors, and provides examples of applications like pollution monitoring and defense. Advantages include early warning systems and avoiding spoofing, while limitations include environmental impacts and limited battery power. In conclusion, the goal is to overcome limitations and enable advanced applications like audio and video transmission underwater.

1. E.HARIPRIYA
FIRST YEAR
M.TECH
17304011
1
UNDERWATER WIRELESS COMMUNICATION
SYSTEM
DEPARTMENT OF
ELECTRONICS ENGINEERING
EENG-521: CREDIT SEMINAR

2. Content
 Introduction
 History
 Underwater Wireless Communication
 Necessity of Underwater Wireless Communication
 Underwater Wireless Communication Technology
 Applications
 Advantages
 Limitations
 Conclusion
 References
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3. Introduction
WIRELESS:
 Wireless communication is the transfer of
information or power between two or more
points that are not connected by an electrical
conductor
 Usually, in wireless EM waves are used in
transmission of information is from one point to
another. But in underwater communication we
use acoustic waves to propagate over large
distances
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4. History
 The science of underwater acoustics began in
1490, when Leonardo Da Vinci, stated.
 In 1687, Isaac Newton wrote his Mathematical
Principles of Natural Philosophy which included
the first mathematical treatment of sound in
water.
 In 1877, Lord Rayleigh wrote the theory of
sounds and established the modern acoustic
theory
 In 1919, the first paper was published on Under
water Acoustics
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5. Underwater Wireless
Communication(UWC):
What is UWC?
 UWC is a technique of sending and receiving
the message, image, videos and information
below the water
 There are several ways of employing such
communication but the most common is using
hydrophones
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6. Necessity of Underwater Wireless
Communication
Wired underwater is not feasible in all situations
as shown below :
 Temporary experiments
 Breaking of wires
 Significant cost of deployment
 Experiment over long distances.
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7. Underwater Wireless
Communication Technology
 Radio waves do not propagate well underwater
 UWC based on acoustic links characterized by large
propagation delays
 Acoustic channels have low bandwidth
 The propagation speed of acoustic signals in water is
typically 1500 m/s
 It cannot rely on the Global Positioning System (GPS) 7

8. Two Underwater Network Topologies :
(a)Centralized Network Topology
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9. 9
(b)Decentralized Network Topology

10. Factors Influencing Acoustic
Communication
 Path loss
 Noise
 Multi-path propogation
 High propogation delay
 Doppler frequency spread.
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11. Hardware Platform Interfaces
Sensor Interface:
Must develop common interface with
different sensors (chemical, optical, etc.) and
communication elements (transducer)
Wide (constantly changing) variety of sensors,
sampling strategies
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12. Cont.…
 Communication Interface:
 Amplifiers, Transducers
 Signal modulation
Hardware:
Software Defined Acoustic Modem (SDAM)
Reconfigurable hardware to provide,
flexible, high performance implementations
for DSP applications.
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13. Acoustic Modem
 This channel improved signal to noise ratio
 It has high performance, error detection and
correction coding scheme which reduces bit error
rate to less than 10-7.
Parts of an acoustic modem:
 DSP Board
 AFE(Analog Front End) Board
 DC/DC Converter
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14. Data Transmission in Modem
When no data is being transmitted, the modem
stays in sleep mode. This results in low power
consumption
Similarly when the data is to be transmitted , the
modem receives data .
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15. Different Modems
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16. Advanced Modems Available
Characteri
stics
UWM1000 UWM2000 UWM3000 UWM4000
Depth(in m) 200 1000 - 6000
Range(in
m)
300 1500 3000 4000
Power
consumptio
n
1 4 20 -
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17. Underwater Acoustic Sensor
Networks (UW-ASN)
 Group of sensors and vehicles deployed
underwater and networked via acoustic links,
performing collaborative tasks
 Equipment
◦ Autonomous Underwater Vehicles (AUVs)
◦ Underwater sensors (UW-ASN)
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18. UW-ASN Communication
Architecture
2-D ARCHITECTURE
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19. 2-D Architecture
 UW-sinks are equipped with two acoustic transceivers,
horizontal and vertical transceivers
 The first is used by he UW-sinks to communication with the
sensor nodes, while the second is used by the UW-sinks to
rely data to a surface station
 Vertical transceivers must be long range transceivers for
deep water application. The surface station is equipped with
multiple acoustic transceivers, one for each UW-sink
deployed.
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20. 3-D Architecture
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21. Applications
 Seismic monitoring
 Pollution monitoring
 Ocean currents monitoring
 Equipment monitoring and control
 Defence
 Search and Rescue missions
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22. Solar Powered AUVs
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 It is a designed to provide better observation and
monitoring of complex aquatic systems

23. Advantages
 Used to provide early warnings of tsunamis
generated by under sea earthquakes
 It avoids data spoofing
 It avoids privacy leakage
 Pollution monitoring
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24. Limitations
 Underwater sound propagation is highly
affected by environmental and natural factors
 Battery power is limited
 Multipath and fading problems
 High bit error rate
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25. Conclusion
The main objective is to overcome the present
limitations and implement advanced technology
for oceanographic research and cope up with the
environmental effects on the noise performance of
acoustic systems to compete with the future
challenges like effective transmission of audio and
video signals etc.
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26. References
1)ww.google.com
2)www.wikipedia.com
3)www.studymafia.org
4)www.gleonrcn.org
5)www.link-quest.com/oceans2000.pdf
6)Underwater wireless optical comunication –Hemani Kaushal &
Georges Kaddoum : Published in : IEEE Access(volume 4)
7)www.ieee.org/organizations/pubs/newsletters
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27. THANK YOU
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