COMMUNICATION/NETWORKING
IN CHALLENGING ENVIRONMENTS
I. F. AKYILDIZ
Broadband & Wireless Networking Laboratory
School of Electrical and Computer Engineering
Georgia Institute of Technology
Tel: 404-894-5141; Fax: 404-894-7883
Email: ian@ece.gatech.edu
Web: http://www.ece.gatech.edu/research/labs/bwn
KEY WIRELESS NETWORKING TECHNOLOGIES
IN THE NEXT DECADE - OVERVIEW
* WIRELESS LANs
* SATELLITE NETWORKS
* AD HOC & SENSOR NETWORKS
* WIRELESS MESH NETWORKS
(MARIO GERLA, I. AKYILDIZ)
(NITIN VAIDYA, HARI B.)
* WiMAX
* COGNITIVE RADIO NETWORKS
* (MOBILE SOCIAL NETWORKS!!)
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COMMUNICATION/NETWORKING
IN CHALLENGING ENVIRONMENTS
 UNDERGROUND APPLICATIONS
 UNDERWATER APPLICATIONS
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Wireless Underground Sensor Networks
I.F. Akyildiz and Erich Stuntebeck,
“Wireless Underground Sensor Networks: Research
Challenges”, Ad Hoc Networks (Elsevier) Journal, Nov. 2006.
Sink
Soil Condition
Sensor
-Water
-Salinity
-Temperature
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APPLICATIONS

Sports field monitoring
– Golf courses
– Soccer fields
– Baseball fields
– Grass tennis courts
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FURTHER APPLICATIONS
 Infrastructure monitoring
–
–
–
–
–
pipes
electrical wiring
liquid storage tanks
underground fuel tanks
septic tanks
Border Patrol and Security
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FURTHER APPLICATIONS
Coal Mines (TUNNELS)
Diamond/Gold/Platinum Mining (TUNNELS)
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Underground Channel Challenges
Parameter
Dynamic Channel
Effect on Path
Loss
Frequency
Water content
Temperature
% Sand particles in soil
% Clay particles in soil
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Underground Challenges
Power Constraints
– Difficult/impossible to change the batteries for
underground devices
– High radio power necessary due to extreme path losses
Low data rate
– Channel conditions are best at low carrier frequencies
– Less bandwidth is available at lower frequencies
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Underground Challenges
 Antenna Design
 Extremely Lossy Environment
– Strong FEC needed to help overcome weak signals,
but must not use excessive energy in processing
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Underground Challenges
• EM Waves or
• Magnetic Induction or
• Seismic Waves????
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Underground Challenges
 MODULATION (EARLY WORK  ANALOG COM.)
(LATELY’04  QPSK, QAM 16, QAM 32); 4kHz carrier,10W, 2kbps)
 Capacity Study
 Tradeoff between Capacity and Reliability
•
•
•
•
•
MAC
Routing
End-to-End Reliability
Error Control
Packet Size
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UNDERWATER NETWORKING
I.F. Akyildiz, D. Pompili, T. Melodia, “Underwater Acoustic
Sensor Networks: Research Challenges”,
Ad Hoc Networks (Elsevier) Journal, March 2005
•
Available bandwidth is severely limited
• UW channel is severely impaired (in particular due to
multi-path and fading)
• Very long (5 orders of magnitude higher than in RF
terrestrial channels) and extremely variable propagation
delays
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CHARACTERISTICS OF UNDERWATER NETWORKS
•
Very high bit error rates and temporary losses of
connectivity (SHADOW ZONES)
• Battery power is limited and usually batteries cannot be
recharged; no solar energy!!
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Transmission Loss
(URICK PROP. MODEL)
TL  X  Log (d )   ( f )  d  A
Attenuation due to
geometric spreading
TL increases with increasing freq. & distance
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Attenuation due to Attenuation due to
multipath
absorption
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Our Contributions for UW-ASNs
SensorApp
Developed @BWN-Lab:
-AcousticProp Model
-AcousticChannel
-AcousticPhy
-CDMA-based MAC
-SensorRouting
WirelessAgent
SensorRouting
LL
Queue
CDMA-based MAC
AcousticProp Model
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AcousticPhy
AcousticChannel
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CROSS LAYER SOLUTION
D. Pompili and I.F. Akyildiz, “Cross-layer Protocol Suite
for Underwater Acoustic Sensor Networks,” July 2007
PHY Layer
Traditional Approach
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Application Layer
Energy Management Plane
MAC Layer
Cross-Layer
Melting
Cross-Layer Management Plane
Network Layer
Energy Management Plane
Transport Layer
Cross-Layer Management Plane
Application Layer
Our View
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WHAT IS THE STATUS?
 PAPER WRITING RACE STARTED !!!!
 COMMUNICATION PROTOCOLS !!!
 MODULATION TECHNIQUES ((D) PSK, 16 QAM), OFDM??
 SYNCHRONIZATION ALGORITHMS
 LOCALIZATION ALGORITHMS
 CAPTURING THE MOBILITY OF AUVs
 SECURITY
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WHAT IS THE STATUS?
 CAPACITY ANALYSIS
 TRADEFOFF RELIABILITY vs CAPACITY
 DEPLOYMENT (TOPOLOGY) ALGORITHMS
 ERROR CONTROL (FECs, HYBRID ARQs???)
 IN-NETWORK CODING (AGGREGATION/FUSION???)
 MULTIMEDIA COMMUNICATION
 Etc.etc…..
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