Congestion control over internet with uncertainties and input delay based on variable structure control algorithm

In this paper, we introduce an active queue management (AQM) scheme based on variable structure control (VSC) algorithm in order to solve the problem of congestion control in the Internet. A robust variable structure controller is proposed for the robust stabilization of linear input delay network systems with uncertainties. Moreover, we design a sliding surface to minimize the effect of the input delay. In addition, we propose a novel reaching condition to effectively reduce chattering. By applying the reaching condition to the system, the proposed controller can effectively restrain oscillation of the queue length in router. We also discuss the implementation issue of the proposed controller. Matlab simulation results demonstrate that the proposed controller has better stability and robustness than some other AQM schemes in different scenarios.