State-dependent Data Queuing in Shared-resource Networked Control Systems
Johansson, Karl Henrik
Baras, John, S.
In the design of shared resource networked control systems (NCSs), resource managers play an important role to appropriately allocate limited resources across the distributedsystem. They are often used to fairly distribute the limited bandwidth among the medium-sharing entities at the expense of delaying or discarding unnecessary data samples. Considering the rapidly growing volume of information that need to be exchanged, a relevant scenario for efficient resource management is state-dependent data buffering through network queues. In this paper, we propose state-dependent data buffering for shared-resource NCSs, such that both buffer input and output can be adjusted depending on the real-time conditions of the control systems and the communication network. We consider that the transmission decisions at the sensor side are taken by event-based schedulers, and that those data eventually sent for transmission are queued and processed, depending on the available communication resource. To improve the buffer service, we propose a state-dependent buffer discharge method, based on real-time feedback from the communication network. We derive sufficient stability conditions under which the overall NCS with the proposed cross-layer transmission scheme is stable in mean-square sense. Moreover, we show performance improvements resulting from our proposed design in comparison with its state-independent counterpart.Download Full Paper