分布式节点群的参量差分时钟同步算法

结合分布式系统多平台性、通用性、阶段同步性等新特征，提出一种新的分布式节点群参量差分逻辑时钟模型(LCPD)及其同步算法。该模型不修改本地时间，将不确定的网络延迟考虑到差分频率中，通过差分时钟计数值的递归演算和差分频率的收敛校准，获取各节点稳定的计数值，以此作为衡量全网时钟同步的标志。算法采用参考广播、锁相环和协同同步原理，步骤分为零点对时和差分校准。仿真实验表明：该算法一旦同步就不再失步，具有较好的收敛性和稳定性，可满足大规模、异构分布式仿真系统的同步需求。

A Clock Synchronization Algorithm Based on Parametric Difference for Distributed Node Clusters

By analyzing some new features of distributed systems such as multi platform, generality, phase synchronization et al, a novel logic clock model based on parametric difference (LCPD) and its synchronization algorithm for distributed node clusters (SADNC in short) were proposed, In LCPD, the indeterminate network delay is considered into the changing parametric difference frequency (PDF) and the local clock value is not modified. By converging on the dynamic PDF and calculating the counting values of LCPD recursively, all distributed nodes are synchronized in the whole network once each node’s counting value is equivalent and stable. The steps of SADNC algorithm consist of zero point time calibration and synchronization of LCPD, in which some ideas of methods such as parametric difference broadcast, phase locked loop and cooperative time synchronization are adopted. The simulation experimental results show that the stability and convergence of SADNC are excellent and all nodes hardly can be out of synchronization once they have been synchronized, which can meet the time synchronization requirement of large-scale, heterogeneous distributed simulation systems.