A Stochastic Network Calculus Approach for NCS Performance Analysis

Delay bounds of data transmissions and system buffer bounds are important parameters of quality of service (QoS) in networked control systems (NCS). They are particularly important for the analysis and design. Generally, the characteristic of round-trip time (RTT) of the switched Ethernet used in NCS can leads to increased burst and buffer loss. And the bandwidth allocated to a switch is highly affected by the load from other switches within the same network. As a result, the service provided by the switch is stochastic. So we use stochastic network calculus to analyze these parameters of QoS in the paper. Both virtual-backlog-centric (v.b.c.) stochastic arrival curve and stochastic service curve are introduced to analyze stochastic service guarantees of NCS. Finally, we get the end-to-end delay bound and buffer bound under different violation probability in two network scenarios, by using popular network topologies as well as two scheduling algorithms.