university college dublin adaptive radio modes in sensor networks: how deep to sleep? secon 2008 san...
TRANSCRIPT
UNIVERSITY COLLEGE DUBLIN
Adaptive Radio Modes in Sensor Networks: How Deep to Sleep?
SECON 2008
San Francisco, CA
June 17, 2008
Raja Jurdak
Antonio Ruzzelli
Gregory O’Hare University College Dublin, Ireland
UNIVERSITY COLLEGE DUBLIN
Outline Motivation
Protocols
Energy Model
Performance Evaluation
Conclusion
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Motivation
Need for energy-efficiency in WSNs Radio is a major energy sink Two major approaches for saving radio energy
Duty cycling Wake-up radio
Put radio into sleep mode (either periodically or on-demand)
Current IEEE 802.15.4 radios (e.g CC2420) provide multiple low power modes
Which radio mode is most energy-efficient?
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Radio Sleep Mode Tradeoffs
Deep sleep mode
Light sleep mode
Adapt radio sleep mode to current traffic conditions
µW
mW
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Outline Motivation
Protocols
Energy Model
Performance Evaluation
Conclusion
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Protocols 1/2 BMAC
IEEE 802.15.4
Periodically check for channel activity every T seconds
Sender uses preamble that has length P, with a duration of at least T seconds
Listener
SenderP
Idle Transmission
Data
T
Receiving
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Protocols 2/2RFIDImpulse Wake-up radio
based on RFID Attach tag to
external interrupt pin of MCU
Remotely trigger tag to wake up radio
Enables power down of MCU
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Outline Motivation
Protocols
Energy Model
Performance Evaluation
Conclusion
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Energy Model 1/3Listening Energy LPL
Listening Energy RFIDImpulse
Radio current consumption in sleep mode α
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Energy Model 2/3Switching Energy (for one state transition)
Cumulative Switching Energy (LPL)
Cumulative Switching Energy (RFIDImpulse)
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Energy Model 3/3Microcontroller Energy
Transmission Energy
Reception Energy
Sleeping Energy
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Outline Motivation
Protocols
Energy Model
Performance Evaluation
Conclusion
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Performance Evaluation
Apply energy model to following scenarios
Explore inter-dependencies among MAC protocols, node platforms, and traffic load in WSNs Energy tradeoffs Radio sleep mode optimization
Measured current values from node platforms 6-level binary tree static topology
BMAC 802.15.4 RFIDImpulse
MicaZ X X X
TelosB X X X
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Total Energy Low Traffic
MicaZ
TelosB
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Energy Tradeoffs Low Traffic
MicaZ
TelosB
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Total Energy High Traffic
MicaZ
TelosB
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Energy Tradeoffs High Traffic
MicaZ
TelosB
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Power Consumption versus Data Rate
MicaZ TelosB
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To Conclude
Contributions Proposed adaptive sleep modes according to current traffic
activity Presented comprehensive and generalizable energy model
for evaluating energy consumption Evaluated performance with 3 protocols and 2 node
platforms with measured current values Identified suitable radio sleep mode/protocol for given traffic
load on each node platform
Future workImplement mechanism to enable nodes to adapt their sleep
mode on the fly according to current traffic load
