中文摘要：

针对水声通信传播延迟长和节点移动性强的问题,提出一种水声传感器网络中成簇时间同步协议。该协议将时间同步分为簇间同步和簇内同步两个过程,并且通过簇间同步和簇内同步的局部并发执行减少同步过程中产生的报文数量。此外,该协议在计算时钟频偏和相偏的过程中通过区分因为节点移动性造成的下游链路和上游链路传输延迟的不同来提高同步精度。仿真结果表明,与其他同步协议相比,成簇时间同步协议可以在降低同步误差的同时,有效减少网络中同步报文的数量,从而达到降低能量消耗的目的。

英文摘要：

Aiming at the problem of high propagation delay and node movement in underwater acoustic sensor networks （UWASNs） ,this paper presented a cluster-wise time synchronization （CWTS）protocol. It divided the time synchronization process of CWTS into two processes, which were inter-cluster synchronization process and intra cluster synchronization process, and part of them could be executed concurrently for reducing the number of packets generated in synchronization. Moreover, during the process of calculating clock skew and offset ,CWTS distinguished the propagation delay of ＇downlink from that of up- link caused by node movement in order to improve time synchronization accuracy. Simulations demonstrate that CWTS can re- duce synchronization errors as well as the number of synchronization packets than traditional protocols ,which in turn achieves the purpose of reducing energy consumption.