Optimal Event-Based Channel-Hopping Strategy for Networked Control Systems

This paper focuses on the problem of wireless data transmission in a networked control system (NCS), where a sensor transmits measurements to an estimator over a selected channel from a pair of available channels. The objective is to design an optimal event-based channel-hopping strategy (EB-CHS) to minimize the linear quadratic Gaussian (LQG) control cost while satisfying the energy constraint of the sensor. A stationary EB-CHS is first proposed by utilizing feedback information. Then, through a Markov decision process (MDP), a structural feature of the optimal strategy is revealed, and a necessary condition for the optimal strategy is provided. Furthermore, a sufficient and necessary condition for the convergence of the LQG control cost under the optimal strategy is established. Compared with the existing time-based channel-hopping strategies, the proposed optimal EB-CHS can effectively reduce the LQG control cost while keeping the energy constraint. Finally, the results are verified by two numerical examples.