Performance analysis of networked control systems over AWGN fading channels

In this paper, the optimal performance of multi-input and multi-output (MIMO) linear time-invariant (LTI) discrete-time networked control systems (NCSs) are investigated based on state-space representation. In communication channels, channel fading, additive white Gaussian noise (AWGN) and scaling parameter matrix are considered. An average performance index is constructed. Moreover, the control energy and the output energy of the system are considered simultaneously in the output regulation performance. The scaling parameter matrix is introduced, which may be considered as an encoder or modification on the channel. The optimal regulation performances of the system are obtained, and the relationship is given between the optimal regulation performances and the steady-state solution of the corresponding algebraic Riccati equation (ARE). Results indicate that the optimal performance is influenced by the non-minimum phase zeros, unstable poles, the scaling parameter matrix, and the characteristics of the communication noise and fading. In addition, the channel power constraint is considered in Theorem 2. We introduce a novel power weighting factor, which can weigh the relative importance of system output and channel input energy. The obtained results will give some guidance for the design of NCSs. Finally, a simulation example is given to demonstrate effectiveness of the theoretical results. (C) 2017 Elsevier B.V. All rights reserved.