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AquaTools: An Underwater Acous3c Networking Simula3on Toolkit
Anuj Sehgal Iyad Tumar
Jürgen Schönwälder
Mo3va3on
• Radio and op3cal communica3on channels are not efficient • Radio requires very low frequencies (30-‐300 Hz) • High aOenua3on
• Fabrica3on and off-‐shore tes3ng is extremely expensive • Several thousands for a dependable modem • Thousands per day in off-‐shore deployment costs
• Channel performance is dependent on ambient condi3ons • Change in temperature, acidity and
salinity changes system performance
• No dependable simulators exist to simulate underwater networks • MATLAB simula3ons provide channel
modeling capabili3es • Networks also need rou3ng, MAC,
applica3on layer simula3ons
Related Work
• Nsmiracle based underwater channel simula3on module (Harris et al) • Nsmiracle is an extension of ns2 • Only MAC and PHY layer supported • Not possible to test a full scale network
• Underwater LAN designed in OPNET (Sozer et al) • Task specific simula3on • Sta3c environmental parameters • Node mobility not accounted for
• MATLAB based simula3ons • Plenty in number and easy to set up • No possibility to define topologies, packet losses/collisions, rou3ng and
transport layer
Mathema3cal Model
• Ainslie & McColm Model (AOenua3on by Absorp3on)
• Ambient noise
• Signal-‐to-‐noise Ra3o (SNR)
• Transmission Loss
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10logA(l, f ) = k⋅ 10log l + l⋅ logα
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SNR(l, f ) =P
A(l, f )N( f )Δf
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SNR(l, f ) =P
A(l, f )N( f )Δf
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SNR(l, f ) =P
A(l, f )N( f )Δf
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α = 0.106 f1 f2
f12 + f 2
epH −80.56
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+0.52 1+T43
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+4.9 ×10−4 f 2e−
T27
+D17
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⎝ ⎜
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10logNt ( f ) =17 − 30log f
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10logNth ( f ) = −15 + 20log f
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10logNs( f ) = 40 + 20(s − 0.5)€
10logNw ( f ) = 50 + 7.5w12
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+ 20log f − 60( f + 0.03)€
+ 20log f − 40( f + 0.4)
Simula3on Toolkit
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• AquaTools provides an implementa3on for the components of the ns2 func3onal model – enabling usage of any exis3ng ns2 modules.
• The Propaga3on, Channel and Physical Layer models are implemented. Modula3on model is adopted from ns2 itself.
Simula3ons Setup
• Simula3on setup can be done by defining modem characteris3cs, node mobility and traffic flows.
• Important channel parameters can be setup simply by sedng values for appropriate Tcl variables.
Results – Propaga3on Delay
• Propaga3on delay results mimic the shape of the sound velocity profile used – indica3ng an accurate performance.
Results – Channel Capacity
• As expected, the channel capacity predicted reduces logarithmically with distance and increases with transmission strength.
Results – Energy Consump3on
• Studies performed using AquaTools have confirmed that using a high power high-‐data rate modem for transmidng data over shorter hops can save energy.
0.1
1
10
100
1000
10000
0 0.5 1 1.5 2 2.5 3
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on
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d (
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Transmitted Data (MB)
High Rate ModemLow Rate Modem
Conclusions & Future Work
- The AquaTools simula3on toolkit is based on the ns2 simulator. - Widely used simulator. - Easy to write Tcl scripts.
- The obtained results are within bounds of numerical evalua3ons. - Numerically correct results. - Need to be compared to real world deployments
- The simulator provides a method for developing and tes3ng rou3ng, transport and applica3on layer protocols as well.
Relevant References
- A. F. Harris and M. Zorzi, “Modeling the underwater acous3c channel in ns2,” in ValueTools ’07, ICST, Brussels, Belgium, 2007, pp. 1–8.
- E. M. Sozer, M. Stojanovic, and J. G. Proakis, “Design and simula3on of an underwater acous3c local area network,” in Proc. Opnetwork 99,1999.