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Power Consumption Measurement and Clock Synchronization onLow-Power Wireless SensorNetworks

Author : Yu-Ping Chen, Quincy Wu

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Introduction• Applications of Wireless Sensor Networks

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Introduction cont.• Low-Power WiFi system architecture

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Introduction cont.• Digital oscilloscope connection diagram.

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Power Consumption Measurement• Low-Power WiFi and ZigBee

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

--The stand-by status of ZigBee.

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Power Consumption Measurement cont.

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--The start- up status of Low-Power WiFi.

--The start- up status of ZigBee.

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Power Consumption 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

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Clock Synchronization• Clock synchronization of Low-Power WiFi devices by

NTP.

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

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Conclusion and Future work

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• Compared 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 cont.

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• 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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Thanks for your attention.

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