Discrete-time integral sliding-mode flow control for connection-oriented communication networks

In this paper, a novel discrete-time integral sliding-mode control (DISMC) scheme for connection-oriented communication network is proposed. Network is modeled as an n^th order discrete system whose available bandwidth variations at the bottlenecked link act as an exogenous unmatched disturbance. The proposed scheme is characterized by discrete-time integral sliding manifold which inherits the desired properties such as elimination of reaching phase, full order sliding manifold with pole assignment etc. In particular, comparing with the existing discrete flow control scheme, the new scheme ensures more precise tracking with O(T²) steady-state error for state regulation with widely adopted delay-based disturbance estimation. Surface parameters are so chosen to minimise the effect of unmatched uncertainty. Simulation results shows that discrete-time ISMC achieves more effective control performance under the adverse influence of unmatched disturbances, meanwhile eliminating the reaching phase.