一种基于信标的低开销无线TSN时钟同步方法  

A low-overhead wireless TSN clock synchronization method based on beacon

作　　者：张鹏 龚龙庆[1] 徐丹妮[1] ZHANG Peng;GONG Longqing;XU Danni(Xi′an Microelectronics Technology Institute,Xi′an 710054,Shaanxi,China)

机构地区：[1]西安微电子技术研究所,陕西西安710054

出　　处：《微电子学与计算机》2022年第10期80-87,共8页Microelectronics & Computer

摘　　要：随着制造业智能化水平的提升,工控领域对于实时通信、低成本部署和灵活组网的要求越来越高,推动着时间敏感网络(Time Sensitive Networking,TSN)向无线通信领域发展.IEEE802.11标准是使用最广泛的无线通信协议,但是由于其定义的带有冲突避免的载波侦听多路访问机制(Carrier Sense Multiple Access with Collision Avoid,CSMA/CA)存在随机退避、实时性差等特点,导致TSN无法直接应用到无线网络.建立无线TSN的首要任务是实现端到端的时钟同步,针对IEEE802.11自身同步机制对上层同步支持缺失的问题,提出一种面向无线网络通信的基于信标帧的时钟同步方法,与精确时间协议(Precision Time Protocol,PTP)等主流时钟同步机制相比,该方法合理利用无线信道中的信标流量,显著降低了同步所需的网络开销.通过在开源平台openwifi上运行该同步机制与PTP进行对比实验,结果表明这种同步方法能够以远低于PTP的网络开销达到与PTP同一个量级的μs级同步精度,为将TSN推广至无线网络奠定基础.With the improvement of the intelligent level of the manufacturing industry,the industrial control field has higher and higher requirements for real-time communication,low-cost deployment and flexible networking,which promotes the development of Time Sensitive Networking(TSN)to the field of wireless communication.The IEEE802.11 standard is the most widely used wireless communication protocol,but due to its definition of Carrier Sense Multiple Access with Collision Avoid(CSMA/CA),there are random backoffs and poor real-time performance.Due to its characteristics,TSN cannot be directly applied to wireless networks.The primary task of establishing a wireless TSN is to achieve end-to-end clock synchronization.Aiming at the lack of support for upper-layer synchronization by IEEE802.11's own synchronization mechanism,this paper proposes a beacon frame-based clock synchronization method for wireless network communication.Compared with mainstream clock synchronization mechanisms such as Precision Time Protocol(PTP),this mechanism makes reasonable use of the beacon traffic in the wireless channel and significantly reduces the network overhead required for synchronization.The comparison experiment between this synchronization mechanism and PTP was done on the openwifi platform.The results show that this synchronization method can achieve the same order ofμs-level synchronization accuracy as PTP at a much lower network overhead than PTP.This is in order to extend TSN to wireless networks.Lay the foundation.

关 键 词：TSN 时钟同步 无线网络 openwifi 

分 类 号：TP393.1[自动化与计算机技术—计算机应用技术]