AquaTools: An Underwater Acous!c Networking Simula!on Toolkit

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) ⎛ T
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⎝ 43 ⎠⎝ 35 ⎠ f 2 + f 2
f1 + f 2
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• 
Ambient noise • 
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Transmission Loss 10log A(l, f ) = k⋅ 10log l + l⋅ log α
10log N t ( f ) = 17 − 30log f
10log N th ( f ) = −15 + 20log f
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10log N w ( f ) = 50 + 7.5w
1
2
+ 20log f − 40( f + 0.4)
10log N s ( f ) = 40 + 20(s − 0.5)
+ 20log f − 60( f + 0.03)
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• 
Signal-­‐to-­‐noise Ra3o (SNR) SNR(l, f ) =
P
A(l, f )N( f )Δf
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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 10000
High Rate Modem
Low Rate Modem
Power Consumed (kJ)
1000
100
10
1
0.1
0
0.5
1
1.5
2
2.5
3
Transmitted Data (MB)
• 
Studies performed using AquaTools have confirmed that using a high power high-­‐
data rate modem for transmidng data over shorter hops can save energy. 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.