| With the continuous development and deep integration of information technology and manufacturing technology,reliable deterministic communication is urgently needed in fields such as the Industrial Internet,automotive,and mobile communications,aiming to provide interconnection for devices that require accurate time information to support various emerging use cases.Supported by a series of standards,time-sensitive networking can provide time deterministic services and ensure real-time communication quality.TSN is also gradually being used in time-sensitive applications such as industrial automation to ensure deterministic communication within the local area network.As intelligent manufacturing becomes more and more complex,the need for crossdomain collaborative production becomes increasingly urgent.Crossdomain interconnection between multiple TSN networks and reliable collaboration of devices have become key issues in the development of industrial communications.Among them,end-to-end cross-domain time synchronization is a prerequisite for the success of large-scale timesensitive applications such as remote control and factory interconnection and plays an important role in ensuring mission-critical communications with high reliability and low latency.In response to the cross-domain time service requirements of TSN,this paper studies the software-defined time-sensitive networking crossdomain time service scheme and the TSN cross-domain network time error compensation method respectively,and proposes a software-defined timesensitive networking architecture and TSN cross-domain time service mechanism,and establishes a cross-domain time synchronization model;and a time error compensation algorithm is proposed to realize the accurate transfer of time in the TSN cross-domain network,so as to meet the improvement needs of various use cases in terms of time synchronization accuracy and stability,which further enhances time synchronization capability of the TSN cross-domain network and expands the application scope of TSN cross-domain network.The specific work and research contents of this paper are as follows:(1)The research progress of time service technology,TSN technology,and TSN cross-domain communication is investigated,and a softwaredefined time-sensitive networking cross-domain time service scheme is proposed.The solution introduces the SDN paradigm,proposes a softwaredefined time-sensitive networking architecture,decouples network data forwarding and network control functions,and introduces a collaborative controller in the control plane for centralized logic control and resource management of the TSN cross-domain network,which greatly improves the flexibility of the network.Moreover,the network controllers and control data plane interface are designed in the scheme,and the TSN crossdomain time service mechanism is proposed.Time synchronization is constructed as a network function of the TSN cross-domain network.In the scheme,the transmission of time information and synchronization control are separated,and the time error compensation is uniformly implemented by the control plane.(2)Based on the TSN cross-domain time service scheme,a TSN cross-domain time synchronization model is established.Through the process of gPTP time synchronization in the TSN domain and PTP time synchronization between TSN domains,the end-to-end time offset between the terminal slave clock and the network master clock in the TSN crossdomain network can be obtained.In addition,a time service experiment environment is built to analyze the time service performance in the TSN multi-hop network and verify the TSN cross-domain time service scheme.The experimental results show that TSN cross-domain time service can be effectively implemented,and the TSN cross-domain time service performance needs to be further improved.(3)A TSN cross-domain network time error compensation method is proposed.First,the time error in the process of TSN cross-domain time synchronization is analyzed in detail,and the main factors affecting the time synchronization performance are introduced.The time error in the TSN cross-domain network is divided into static time error and dynamic time error.Then,a time error compensation algorithm of joint phase offset estimation and Kalman filtering is proposed to achieve end-to-end time compensation,which is used to improve the performance of TSN crossdomain time synchronization.Among them,the phase offset estimation is used to compensate for the static time error,and the Kalman filter algorithm is used to compensate for the dynamic time error.Finally,the experimental test is carried out.The results show that the time error compensation method can effectively reduce the time error in the process of TSN cross-domain time synchronization,and significantly improve the time synchronization accuracy and time synchronization stability of the TSN cross-domain network.It shows that the TSN cross-domain network can provide a high precision time synchronization service. |
