Time synchronization is indispensable for convenient network management, device monitoring, security, and other fundamental operations in industrial wireless sensor networks (IWSNs). Over the past few decades, a wide variety of highly accurate clock synchronization protocols have been investigated by employing powerful statistical signal processing techniques. However, most two-way exchange estimation schemes do not readjust the node's local clock upon every resynchronization before the clock parameters are estimated. And it may not be appropriate in IWSNs where time synchronization is consistently required. Based on the two-way message exchange mechanism, this paper investigates the clock synchronization schemes of active node and overhearing node with immediate clock readjustment. The maximum-likelihood estimators of the clock skew and the corresponding Cramer_Rao lower bounds are derived assuming Gaussian delays. Simulation and experimental results validate the performance of the proposed estimators.

中文翻译：

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工业无线传感器网络中基于双向消息交换机制的时间同步时钟偏差估计


时间同步对于工业无线传感器网络 (IWSN) 中便捷的网络管理、设备监控、安全和其他基本操作不可或缺。在过去的几十年中，人们通过采用强大的统计信号处理技术研究了各种高精度时钟同步协议。然而，大多数双向交换估计方案在估计时钟参数之前不会在每次重新同步时重新调整节点的本地时钟。它可能不适合始终需要时间同步的 IWSN。基于双向消息交换机制，研究了具有即时时钟调整功能的主动节点和监听节点的时钟同步方案。时钟偏差的最大似然估计量和相应的 Cramer_Rao 下界是在假设高斯延迟的情况下导出的。仿真和实验结果验证了所提出的估计器的性能。