| Wireless sensor network belongs to the next generation of sensor networks. This new type of technology integrates the frontier technologies in the research fields of computer technology, Mechanical and electrical technology, network technology,etc. As the research development continues to mature, the technology plays a successful role in more and more application environment.Based on the specific environment of the strip-based network,the application of wireless sensor network not only reduce the cost of wiring and the energy consumption of the system but also ensure the security and stability.Urban lighting management system is the typical application of wireless sensor networks in the strip-based networks.As one of the wireless sensor network support technology, the clock synchronization technology is very important for wireless sensor network applications and development. Considering the energy consumption and cost,trying to reduce the sensor node communication overhead and extend node lifetime become one of the goals in research. To improve the existing clock synchronization method,efforts should be made not only to meet the requirement of the system under the premise of synchronous accuracy but also to guarantee high efficiency and energy saving.To design such a wireless sensor network clock synchronization method is the key of this paperIEEE802.15.4/Zigbee protocol is analyzed in this paper firstly. The framework and the technical characteristics of Zigbee protocol are summarized. Secondly,the advantages and disadvantages of these methods are got by analyzing and comparing these existing wireless sensor clock synchronization methods. Based on that mentioned above,in this paper,a new clock synchronization method which based on local clock model compensation and used in urban lighting management system is introduced.Considering the characteristics of the actual urban lighting management system,, routing nodes are selected on the basis of RSSI parameters.The clock correction of the root node is made everytime when the time synchronization process begin. Clock drift of the nodes are analysed during the time synchronization process and compensation models are got by formula derivation.This method reduce the synchronous communication cost and improve the synchronization accuracy.The RSSI and LQI mean average corresponding to the distance between nodes are obtained by test on the urban lighting management system.The feasibility of using this method in the platform to select routing nodes are validated. Then seceral time synchronization methods are chosen and tested on this system.The test results validated that the method proposed can be applied to this system.This method shows improvement compared with other methods. |
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