Time Synchronization Application in Wireless Sensor Network: A Wireless Sensor Network Based Distributed Measurement System under Precision Time Protocol

Time synchronization is an important aspect in wireless sensor networks, especially in distributed measurement system. IEEE 1588 is a standard for precise clock synchronization for network measurement and control systems in LAN environment. In the thesis, we present a time synchronization mechanism, named Hierarchy Reference Broadcast Synchronization (HRBS), for WSN based on IEEE 802.15.4 standard. The proposed system architecture is a hybrid of PTP protocol and HRBS algorithm. It works in three steps. The Internet server receives the UTC time from GPS. PTP synchronization is used to translate its clock value to the server?s clock by other devices in LAN. One of the synchronized devices is connect to the sensor node in the wireless sensor network. The synchronized device sent its time stamp to this sensor node. We use HRBS protocol to synchronize all sensor nodes clock in the wireless sensor network. Our implement is using the Linux PCs and Chipcon CC2430. In the finally, we evaluate the PTP and the HRBS time synchronization accuracy and performance. We develop into a wireless sensor network base on the distributed measurement system under precise time protocol.

Jen-Chieh Liu, Studied Computer Science and Information Engineering at National Cheng Kung University. Embedded System Engineer at Geovision Inc., Taipei.