Optimization Design Of Scheduling Mechanism For Time Sensitive Network

The arrival of the industrial intelligent era has redefined the traditional industrial scene.With the addition of intelligent technologies such as large data and cloud computing in the modern industrial scene,the deterministic transmission of industrial information has become the focus of industrial communication network.However,the traditional industrial communication technology,such as fieldbus technology,has been unable to meet the industrial real-time information deterministic transmission requirements.In order to establish the next generation of industrial communication technology,IEEE established a Time Sensitive network(TSN)working group to develop a series of IEEE 802.1transmission protocols,so that traditional Ethernet can meet the deterministic transmission requirements of industrial real-time information,and TSN is regarded as the next generation of industrial information transmission network common technology.Therefore,in order to ensure the deterministic transmission requirements of traffic in TSN,this thesis studies the deterministic transmission performance guarantee and network resource optimization methods under two different scheduling mechanisms: no-wait scheduling and frame preemption scheduling.In order to improve the transmission reliability of time-triggered traffic in the network and the schedulability of flows in the network under the no-wait scheduling mechanism,the redundant transmission mechanism and no-wait scheduling are co-designed.In this paper,a network model of time-triggered traffic redundancy transmission in TSN is established,and a Frame Redundancy Transmission(FRT)mechanism is designed.A Minimum Conflict Tree(MCT)is proposed as the routing path of flows to improve the schedulability of flows in the network,and a heuristic route solving algorithm is designed.This paper proposes a set of no-wait scheduling constraints,and designs a no-wait scheduling algorithm based on Satisfiability Modulo Theories(SMT).Simulation results show that the co-design can effectively improve the transmission reliability of time-triggered traffic in the network,and significantly improve the schedulability of flows in the network.Under the frame preemption scheduling mechanism,aiming at the problem that the preemption mechanism reduces the payload and increases the delay in the network,a flow type and priority division algorithm is designed.In order to improve the network payload and reduce the transmission delay,the worst transmission delay of fast and preemptable streams is analyzed based on frame preemption mechanism.A set of frame preemption scheduling constraints is proposed,and an algorithm for solving frame preemption scheduling based on SMT is designed.The results show that the flow type and priority division algorithm can effectively reduce the average delay and maximum delay of the flow in the network,and reduce the preemption consumption of the network to improve the effective load of the network.