Power Consumption Power Consumption Measurement and Clock Measurement and Clock Synchronization onSynchronization onLow-Power Wireless Sensor Low-Power Wireless Sensor NetworksNetworks

Author : Yu-Ping Chen, Quincy Wu

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IntroductionIntroductionApplications of Wireless Sensor

Networks

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Introduction cont.Introduction cont.Low-Power WiFi system architecture

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Introduction cont.Introduction cont.Digital oscilloscope connection diagram.

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Power Consumption Power Consumption MeasurementMeasurementLow-Power WiFi

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--The electric current of beaconing status when the WiFi signaling strength is -32 dBm.

--The electric current of beaconing status when the WiFi signaling strength is -79 dBm.

Power Consumption Power Consumption Measurement cont.Measurement cont.

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The start- up status of Low-Power WiFi.

The start- up status of ZigBee.

Power Consumption Power Consumption Measurement cont.Measurement cont.

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The stand-by status of ZigBee.

Power Consumption Power Consumption Measurement cont.Measurement cont.Average power consumption statistics.

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Power State ZigBee Low-Power WiFi

Signaling strength

-32 dBm -79 dBm

Start-up 0.0448 W 0.0396 W

Beaconing 0.0957 W 0.2145 W

Stand-by 0.0756 W 0.0495 W

Clock SynchronizationClock Synchronization

Clock synchronization of Low-Power WiFi devices by NTP.

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Clock Synchronization Clock Synchronization cont.cont.Clock synchronization flow chart with NTP.

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Conclusion and Future Conclusion and Future workworkCompared with traditional WiFi

equipment, the power consumption of Low-Power WiFi is reduced approximate 40%.

The power consumption of Low-Power WiFi with start-up and stand-by status is lower than ZigBee.

The power consumption of Low-Power WiFi device when it is receiving beacons from an AP, is twice of the power consumption at its stand-by status.

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Conclusion and Future Work Conclusion and Future Work cont.cont.The clock synchronization usually

suffers from long latency problems in wireless sensor networks like ZigBee.

We combines Low-power WiFi devices with NTP, it would be crucial to further investigate the efficiency and accuracy of NTP packet transmission.

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