On the stability of prioritized error-based scheduling for resource-constrained networked control systems

The efficient usage of scarce communication resources is a vital necessity in networked control systems. This paper introduces a novel stochastic scheduling scheme for networked control systems with shared access through dynamic priority assignment. The overall system is assumed to consist of multiple control loops closed over a common communication network. A p-powered prioritized error-based (PEB) scheduler decides which transmission requests have the priority for channel access, and subsequently which controllers are updated with the actual states. According to the protocol, the likelihood to allocate the resource to a subsystem increases with a growing p-powered norm of its network-induced error. We show, under very mild assumptions, that the described system scheduled by the PEB protocol is stochastically stable. Moreover, numerical simulations demonstrate a significant reduction of the network-induced error variance in comparison to the other scheduling protocols such as CSMA or round robin.