Research On Time Synchronization Algorithm For Wireless Sensor Networks

Wireless sensor network (WSN) is a special type of Ad-hoc networks. It usually consists of a large number of tiny low-power sensor nodes. The communications between the sensor nodes rely on mutual collaboration in wireless multi-hop manner, and therefore the network is self-organized and self-managed without any infrastructure. Because of the special type of networking, wireless sensor network has been widely used in target tracking, monitoring of critical infrastructures, and scientific exploration in dangerous environments and etc. However, the characteristics of WSN, such as energy constrained, volume constrained and etc, challenge to the design of time synchronization algorithm. Focused on the time synchronization algorithm, this paper studied the problems about security and energy-efficiency, and proposed a novel algorithm of secure time synchronization for dynamic wireless sensor networks and an energy-efficient time-synchronization algorithm for wireless sensor networks.The major job and creative ideas of this thesis are listed as follows:Firstly, a novel algorithm of secure time-synchronization for dynamic wireless sensor networks was proposed. As we all know, the technique of time synchronization is one of the crucial basic services of wireless sensor networks. And it is required in many applications like localization, data aggregation, mobile object tracking, etc. But the characteristics of WSN lead that its synchronization process can be easily attacked by the malicious nodes. Therefore, a novel time synchronization algorithm for dynamic wireless sensor networks was proposed in this paper, and it can prevent the time synchronization process of WSN from the attack of the malicious nodes. Compared to the other time synchronization algorithms, it has prime advantages in the main performance parameters.Secondly, WSN is very different from the other networks, and the energy limitation is the biggest problem. WSN is application oriented, which needs the cooperation between the nodes to accomplish some special tasks. So it is very important to maintain the connectedness of WSN. The ways and means to reduce the energy consuming of the nodes, to balance the energy consuming between all the nodes, and to prolong the life of WSN, are the main challenges during the research on WSN. An energy-efficient time synchronization algorithm was proposed in this paper, and it can reduce the energy consuming during the synchronization process of WSN without any negative influence on the other performance parameters.Thirdly, we designed and carried out the experimental hardware platform of wireless sensor networks, which includes the sensor nodes, the network access point, and the programmer. Based on this platform, we made some experiments about time synchronization algorithm and IPv6. The former experiment indicated the feasibility of the secure time synchronization algorithm referred above. And the latter proved that this platform can work well with the CNGI network stably as a component part of CNGI.The novel ideas and methods in the dissertation have been studied and verified through theoretic analysis and simulations, which have showed the feasibility. These results can be applied and developed into the future related products to enhance the flexibility, efficiency and scalability.