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Work in Progress for Wireless Sensor Networks
Yonghe [email protected]
Dept. of Computer Science and EngineeringThe University of Texas at Arlington
Partially supported by NSF CNS-0721951, NSF IIP 0712433, and Texas ARP
10/22/2007 2
Current efforts
Develop sensor networks that are
Energy efficient – multiple years operation
Easy to use – as web applications to users
Easy to program -- drag and drop
Easy to clean up physically – no one left behind
10/22/20074/25/2007 3
An easier route
Focus on applications that are less demanding
Temperature, humidity, light sensing, etc.
Low data rate at several bytes/node/minute often sufficient
Typical hardware platform: TelosB 250Kbps bandwidth (Zigbee) 8MHz Microcontroller 10KB ram 1MB flash
And an extensive set of overlaying solutions
Over Kill
10/22/2007 4
Hardware
Pseudo-RFID module on board
Use RFID writing No backscattering though Semi-passive for long range
Enable asynchronous communication among nodes
Transmitter directly excites and writes into receiver memory
Always “ON” receiver
Transmit whenever desired No periodic wakeup/sleep, simplified
MAC operation
Sensing
Radio
AntennaPROUD
ActivationMemory
NodePlatform
CPU
Memory
Battery
TX
RX
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Network: asynchronous communication pattern
Overall a store and forward, asynchronous communication architecture
Sensora
Sensorb
Sensor
Sensord
Sensorf
Sensorc
Sensore
Sensor
Sensor
Sensor
Sensorg
Sink
Benefit Utilize the whole time line
Transmission anytime, not in a time window No-need of CSMA/CD MAC
Low rate of data Avoid heavy collisions Avoid idle listening No wakeup synchronization overhead
Energy Efficiency
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Cleaning up
If backscattering enabled,
True RFID capability
Locating and identifying node corpses
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Onboard software
Simplified to be necessary
Using standard Zigbee stack if possible
Quite powerful
Open source
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PC/Sink software
Simplified but limited programming Drag and drop Like labview
Web based visual/management tools
10/22/2007 9
Advanced topics due to asynchronism
Signal processing
Delay reduction
Joint synchronous and asynchronous design
