Design and Implementation of a Time Synchronization Method for UOWC Networks  

作　　者：Weijie Liu Jingyi Zhang Nuo Huang Zhengyuan Xu 

机构地区：[1]CAS Key Laboratory of Wireless-Optical Communications,School of Information Science and Technology,University of Science and Technology of China,Hefei 230027,China

出　　处：《Journal of Communications and Information Networks》2024年第1期56-63,共8页通信与信息网络学报（英文）

基　　金：supported in part by the National Key Research and Development Program of China under Grant 2022YFB2903400;in part by the Strategic Priority Research Program of CAS under Grant XDA22000000;in part by the National Natural Science Foundation of China under Grants 62301525 and 62101526.

摘　　要：Underwater optical wireless communication (UOWC) technology facilitates high-speed data transmission among multiple nodes in underwater networks. Nevertheless, the absence of a common clock poses a challenge to achieving systematic and reliable access for multiple nodes within these networks. This paper presents a time synchronization method for UOWC networks to ensure the successful execution of the media access control (MAC) protocol. In this method, the node obtains timestamps by exchanging messages with the optical access point (OAP). Subsequently, the node calculates the clock drift relative to the OAP and the propagation time,ensuring that transmitted data packets can arrive approximately at the time specified by the OAP. To validate the effect of the proposed method, an experimental UOWC prototype, including the OAP and nodes, is implemented using field programmable gate array (FPGA). The experimental results demonstrate that the maximum difference between the actual arrival times of two data packets that are expected to reach the OAP simultaneously according to the MAC protocol meets the requirements of the quasi-synchronous code division multiple access (QS-CDMA) system, thereby substantiating the effectiveness of this synchronization method.

关 键 词：UOWC time synchronization MAC FPGA QS-CDMA 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]