Research On Time Synchronization Algorithm In Wireless Sensor Networks

Wireless sensor network(WSN) is a typical distributed wireless communication network system, and it integrates the sensor, embedded computing and network communication. Due to the abilities of information collection, data processing and wireless communication, a wireless sensor network is very important for instructing both the theory and the applications in military reconnaissance, environmental monitoring, medical care, industrial production control, scientific exploration in dangerous environments and so on. Time synchronization is a supporting technology in the operation of wireless sensor networks, as the accurate time information is required for applications and protocols of wireless sensor network to work cooperatively. It has also attracted serious concern and become a hot research issue. Consensus algorithm is critical to the research of cooperative control of multi-agent system and it is an effect method for solving cooperative control problem in distributed network. Therefore, there is fine development prospect for using consensus algorithm in time synchronization for wireless sensor network.Distributed consensus time synchronization was researched on the basis of study on consensus algorithm and principle of time synchronization mechanism of wireless sensor network in this paper. The major contribution of this paper is summarized as follow:1. In order to obtain faster convergence in the time synchronization of node and better energy efficiency, a new time synchronization algorithm for wireless sensor network based on cluster topology was proposed. The clustering technique of wireless sensor network was incorporated into the distributed consensus time synchronization. The cluster head is responsible for exchanging messages within the cluster, which improves the energy consumption of distributed time synchronization algorithm. To improve the convergence speed, clock compensation parameters of virtual clocks of every cluster head are assigned with corresponding weights based on the size of each cluster. The simulation results show that the proposed algorithm reduces the communication traffic compared with the DCTS algorithm, and improves the convergence rate due to the combination of clustering topologies.2. In order to characterize the local clock model which is controlled by skew and offset, this paper proposed a distributed second-order consensus time synchronization algorithm, which incorporated the second-order consensus algorithm into time synchronization of wireless sensor networks. Finally, the effectiveness of the proposed algorithm is verified through a number of simulations in a mesh network. It is proved that the proposed algorithm has the advantage of being distributed, asymptotic convergence, and robust to new node joining.3. The second-order consensus problems was discussed for multi-agent systems with dynamic agents and fixed topologies, and a new second-order consensus algorithm incorporating the predictive mechanism was proposed and a convergence analysis related to the eigenvalues of the Laplacian matrix of the corresponding network was provided. It is proved under general conditions related to the second-order consensus algorithm and the network topology that the asymptotic consensus is achieved and the convergence rate is increased via designing a state predictor. The simulation results show that the proposed algorithm improves the convergence rate. Lastly, the proposed second-order consensus algorithm was used for solving the time synchronization problem of wireless sensor network, and the simulation results are provided to verify the effectiveness of the proposed time synchronization algorithm.