Accurate Emulation of Wireless Sensor Networks Hejun Wu Joint work with Qiong Luo, Pei Zheng*, Bingsheng He, and Lionel M. Ni Department of Computer Science The Hong Kong University of Science

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Accurate Emulation of Wireless Sensor Networks
Hejun Wu Joint work with Qiong Luo, Pei
Zheng, Bingsheng He, and Lionel M. Ni
Department of Computer ScienceThe Hong Kong
University of Science Technology, China
Arcadia University, USA
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Wireless Sensor Networks (WSNs)
Proxy


User Client
Sink
Sensor mote
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Wireless Sensor Networks (WSN)
Proxy


User Client
Sink
Sensor mote
Query
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Wireless Sensor Networks (WSN)
Proxy


User Client
Sink
Sensor mote
Query Result
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Motivation of VMNet

• Substitute for sensor nodes in research
• Easy to handle
• Low price
• A realistic controllable environment
• Debugging
• Testing
• Evaluating Performance
• Parameter setting and validation for
• Simulation
• Modeling

Applications
Network protocols
OS
Drivers
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VMNet architecture
VMNet architecture
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Components in a VM
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Virtual Radio Channel
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Key Features of VMNet

• Open architecture
• Easy to transform to other WSN hardware emulation
• Detailed emulation
• CPU instructions
• Operations of the components
• CPU, Sensor and Radio
• Accurate running status logs
• Accurate time emulation
• Granularity microsecond level
• power consumption evaluation

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Open architecture design

• Conflict between generality accuracy
• Generality is desirable
• Ability to emulate various WSNs
• Accuracy
• Close to the specified target WSN
• Highly modularized structure of a VM
• Ensures the reusability
• Virtual socket in a VM
• Uniform interface between modules

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Highly modularized structure
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Performance Evaluation on Applications of WSNs

• Based on the fact that
• Operation and time can be deduced by
• Instructions executed by the CPU in a sensor mote
• An instruction always takes constant time
• VMNet approach in performance evaluation
• Logging and reporting
• Operations and time

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Logging in VMNet

• The operations
• VMNet logs
• Running states
• the operations of each component (e.g. III)
• CPU clocks
• describe the start time and end time

The operations of components
CPU Sensor Radio
Compute (C) Acquire (A) Transmit (T)
Idle (I) Idle (I) Receive(R)
Hibernate (H) Power down (P) Control(C)
Hibernate (H) Power down (P) Idle(I)
Hibernate (H) Power down (P) Power down (p)
A fraction of a VMNet log
Running states Time (In terms of CPU clock cycles)
III 1926031985
IIR 1926032167
CIR 1926034874
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Conclusion

• Detailed emulation
• Useful for many areas in a WSN
• Architecture, OS, and sensor network query
  processing.
• Provides
• parameter and validation for simulation
  modeling
• Performance evaluation
• Especially valuable for query processing
• Query Optimization
• choose a query plan with minimum energy and time
  cost
• Query processor benchmark study

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Future Work

• Power consumption evaluation
• Work in progress
• Scalability
• Mobile WSN emulation
• Graphical Interface for VMNet
• In the near future
• Use multiple PCs to emulate a WSN