Resource-Efficient Hierarchical Transmission-Estimation Co-Design for Wireless Control Systems

In the performance analysis and control of wireless control systems, the high accuracy state estimate is a necessary prerequisite for feedback control. However, it is challenging due to the server interference wireless environment as well as limited spectrum and energy resources. To address this issue, this paper firstly presents a hierarchical framework to lay the foundation to guarantee the prescribed estimation accuracy for WCSs with minimal resource consumption. Under this framework, a resource-efficient hierarchical transmission-estimation co-design approach is proposed to adapt to the system dynamics and communication resources for improving the transmission reliability and reducing the energy consumption. Then, a joint optimization problem subject to constraints of estimation convergence, transmission reliability and resource limitation is formulated to minimize the overall estimation-energy cost for WCSs in terms of estimation error and energy consumption. The solution of mixed integer nonlinear programming problem is got efficiently and effectively with decomposition methods. Finally, simulation results demonstrate that the developed hierarchical transmission-estimation co- design approach has superiorities on improving the estimation accuracy and the resource efficiency. The estimation-energy cost caused with the proposed approach is about 51% and 77% of that with two compared ones without awareness of wireless environment variations and system dynamics, respectively.