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Thomas Watteyne @ EDERC 2010
1. Introduction to Sensor Networks
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1997, the Smart Dust vision
Thomas Watteyne @ EDERC 2010
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2001, Intel Developers Forum
• 800 motes• 8-level dynamic
networkThomas Watteyne @ EDERC 2010
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2001, 29 Palms Demo
Thomas Watteyne @ EDERC 2010
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S. Oh et al, "Tracking and coordination of multiple agents using sensor networks: system design, algorithms and experiments," Proc. of the IEEE, 2007.S. Kim et al, “Health Monitoring of Civil Infrastructures Using Wireless Sensor Networks,” IPSN, Cambridge, MA, April 2007A. Ledezci, http://www.isis.vanderbilt.edu/projects/countersniperJ. Lees et al, “Reventador Volcano 2005: Eruptive Activity Inferred from Seismo-Acoustic Observation”, Jnl, of of Volcanology and Geothermal Research, 2007
Wireless Sensor Networks
Sensor Networks for SecurityStructural Monitoring
Sniper Localization
Environmental Monitoring
Thomas Watteyne @ EDERC 2010
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Automated Meter Reading• Overview
– Urban-wide Water Meter Reading– Coronis Systems, Elster group– Deployed since 2005 in Sable-
d'Olonne, France
• Platform– 25,000 proprietary nodes
• Networking– Static routing tree– Parent association done at
deployment– 10+ years (<.1% duty cycle)
Thomas Watteyne @ EDERC 2010
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Building Automation
Smart Grid Applications
IndustrialAutomation
Industrial Applications
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Barriers to Adoption
Thomas Watteyne @ EDERC 2010
Reliability
Standards
Ease of use
Power consumption
Development cycles
Node size
0% 20% 20% 60% 80% 100%
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Reliability
Reliability is challenged by:• external interference• multi-path fading
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First Challenge: External Interference
IEEE802.11(Wi-Fi)
IEEE802.15.1(Bluetooth)IEEE802.15.4(ZigBee)
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IEEE802.11b/g/nIEEE802.11a/n
First Challenge: External Interference
868 MHz
433 MHz
2.4 GHz 5 GHz
IEEE802.15.4
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First Challenge: External Interference
• 45 motes*
• 50x50m office environment
• 12 million packets exchanged, equaly over all 16 channels
*data collected by Jorge Ortiz and David Culler, UCBPublicly available at wsn.eecs.berkeley.edu
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Second Challenge: Multipath Fading
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Second Challenge: Multipath Fading
• Separate sender and receiver by 100cm
• Have sender send bursts of 1000 packets
• Have receiver count the number of received packets
• Move transmitter around in a 20cmx35cm square and start over
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Second Challenge: Multipath Fading
ch.11Thomas Watteyne @ EDERC 2010
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Second Challenge: Multipath Fading
ch.11 ch.12
0% reliability 100% reliability
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Second Challenge: Multipath Fading
ch.11
ch.13
ch.15
ch.17
ch.12
ch.14
ch.16
ch.18
ch.19
ch.21
ch.23
ch.25
ch.20
ch.22
ch.24
ch.26
changing channel improves performance
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Taking A Real-World Example
• Doherty, Lindsay, Simon. “Channel-Specific Wireless Sensor Network Path Data”, ICCCN 2007.
• 44 nodes, 26 days
Thomas Watteyne @ EDERC 2010
Thomas Watteyne @ EDERC 2010
Thomas Watteyne @ EDERC 2010
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Pathloss
0 50 100 150 200 250 300-100
-90
-80
-70
-60
-50
-40
-30
-20
distance in feet
RS
SI
(dB
m) RSSI does not give
an indication about distance
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Stability over all paths, all channels
Thomas Watteyne @ EDERC 2010
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Stability over all paths, all channels
Thomas Watteyne @ EDERC 2010