Reference model based discrete time sliding mode control of communication networks

In this work, we propose a new sliding mode controller based on a reference model for controlling data transmission rates in a connection-oriented communication network. In the proposed approach, we build a model of the network, which is controlled by a linear quadratic (LQ) optimal controller. Then, the sliding variable of the real network is forced to follow the reference sliding variable generated by this model. This method enables us to preserve the favorable properties of the optimal controller, such as reducing and smoothing out the initial flow rates. Moreover, once the reference model attains the vicinity of the desired state, the designed sliding mode controller is able to react more rapidly to changes in the available bandwidth, ensuring better robustness. Due to this fact, the considered controller can ensure full bottleneck link bandwidth utilization with smaller memory buffers than the LQ optimal one. This important advantage is shown both analytically, and in computer simulations