Research On Time Synchronization Of Wireless Sensor Networks

Wireless sensor networks(WSN), which is made by the convergence of sensor, nested computation, networks and wireless communication technologies, is a newest technology of acquiring and processing information. It can be used for testing, sensing, collecting and processing information of monitored objects and transmitting the information to the customer. Have a wide range of application including military and business. As a new research field, WSN provides lots of challengeable projects to the domestic and international scholars.Time synchronization is a critical piece of infrastructure for any distributed systems and also is an important support technique of WSN. For most Applications such as environment monitoring, navigation guidance need the collected data with accurate time information; any form of sensor data fusion or coordinated actuation requires synchronized physical time for reasoning about events in the physical world. But for most applications of WSN, the requirement of accuracy is not high and the nodes in WSN are extraordinarily limited in resource than in traditional distributed systems, designing energy saving synchronization algorithm under the request of time accuracy is the emphasis of this paper.In this paper, analysis of the characteristics of the existing time synchronization mechanisms, a new multi-hop time synchronization based on the connected dominating sets is proposed which in order to resolve the problem of broadcast storm. First, an enhancement of the connected dominating sets algorithm DRN based on the delete the redundant node is proposed. When the N1(u) can be not connected mutually, but can be connected through the others big id node, so can delete the gateway of the node u. Therefore reduced the number of dominating set nodes is not increase the expense of correspondence.A new multi-hop of Time synchronization algorithm based on the connected dominating sets is proposed, which makes the node of the connection collection as the broadcast node to send message, but the leaf node finishes the time synchronization task of itself not to retransmit the message. The algorithm can reduce the number of message retransmitted, and save the energy expense of broadcast. The simulation on the MATLAB shows that the new algorithm can resolve the problem of broadcast storm that may be caused by the broadcast based on flooding broadcasts and extend the life time of the whole sensor networks, the new algorithm has better performance than the flooding time synchronization protocol.