Time synchronization is a critical middleware service of wireless sensor networks. Researchers have already proposed some time synchronization algorithms. However, due to the demands for various synchronization precis...Time synchronization is a critical middleware service of wireless sensor networks. Researchers have already proposed some time synchronization algorithms. However, due to the demands for various synchronization precision, existing time synchronization algorithms often need to be adapted. So it is necessary to evaluate these adapted algorithms before use. Software simulation is a valid and quick way to do it. In this paper, we present a time synchronization simulator, Simsync, for wireless sensor networks. We decompose the packet delay into 6 delay components and model them separately. The frequency of crystal oscillator is modeled as Gaussian. To testify its effectiveness, we simulate the reference broadcast synchronization algorithm (RBS) and the timing-sync synchronization algorithm (TPSN) on Simsync. Simulated results are also presented and analyzed.展开更多
Time synchronization is one of the base techniques in wireless sensor networks(WSNs).This paper proposes a novel time synchronization protocol which is a robust consensusbased algorithm in the existence of transmissio...Time synchronization is one of the base techniques in wireless sensor networks(WSNs).This paper proposes a novel time synchronization protocol which is a robust consensusbased algorithm in the existence of transmission delay and packet loss.It compensates for transmission delay and packet loss firstly,and then,estimates clock skew and clock offset in two steps.Simulation and experiment results show that the proposed protocol can keep synchronization error below 2μs in the grid network of 10 nodes or the random network of 90 nodes.Moreover,the synchronization accuracy in the proposed protocol can keep constant when the WSN works up to a month.展开更多
考虑到在无线传感器网络中,新节点的加入或老节点的死亡均会导致拓扑呈动态变化,该文研究一种完全分布式二阶一致性时间同步(Second-Order Consensus Time Synchronization,SOCTS)算法。将节点的时钟特性建模成二阶状态方程,按照伪同步...考虑到在无线传感器网络中,新节点的加入或老节点的死亡均会导致拓扑呈动态变化,该文研究一种完全分布式二阶一致性时间同步(Second-Order Consensus Time Synchronization,SOCTS)算法。将节点的时钟特性建模成二阶状态方程,按照伪同步周期广播节点的本地虚拟时间,根据邻居节点的本地虚拟时间的不一致来构造同步控制输入;通过坐标变换将网络的一致性时间同步问题转化为变换系统的稳定性问题,理论分析了SOCTS算法的收敛性和收敛条件,并研究了影响SOCTS算法收敛速度的因素。通过数值仿真实验验证了所提方法的有效性。展开更多
基金Supported in part by National Basic Research Program of P. R. China(2005CB321604) in part by National Natural Science Foundation of P. R. China (90207002)
文摘Time synchronization is a critical middleware service of wireless sensor networks. Researchers have already proposed some time synchronization algorithms. However, due to the demands for various synchronization precision, existing time synchronization algorithms often need to be adapted. So it is necessary to evaluate these adapted algorithms before use. Software simulation is a valid and quick way to do it. In this paper, we present a time synchronization simulator, Simsync, for wireless sensor networks. We decompose the packet delay into 6 delay components and model them separately. The frequency of crystal oscillator is modeled as Gaussian. To testify its effectiveness, we simulate the reference broadcast synchronization algorithm (RBS) and the timing-sync synchronization algorithm (TPSN) on Simsync. Simulated results are also presented and analyzed.
文摘Time synchronization is one of the base techniques in wireless sensor networks(WSNs).This paper proposes a novel time synchronization protocol which is a robust consensusbased algorithm in the existence of transmission delay and packet loss.It compensates for transmission delay and packet loss firstly,and then,estimates clock skew and clock offset in two steps.Simulation and experiment results show that the proposed protocol can keep synchronization error below 2μs in the grid network of 10 nodes or the random network of 90 nodes.Moreover,the synchronization accuracy in the proposed protocol can keep constant when the WSN works up to a month.
文摘考虑到在无线传感器网络中,新节点的加入或老节点的死亡均会导致拓扑呈动态变化,该文研究一种完全分布式二阶一致性时间同步(Second-Order Consensus Time Synchronization,SOCTS)算法。将节点的时钟特性建模成二阶状态方程,按照伪同步周期广播节点的本地虚拟时间,根据邻居节点的本地虚拟时间的不一致来构造同步控制输入;通过坐标变换将网络的一致性时间同步问题转化为变换系统的稳定性问题,理论分析了SOCTS算法的收敛性和收敛条件,并研究了影响SOCTS算法收敛速度的因素。通过数值仿真实验验证了所提方法的有效性。
