Observer-based sliding mode control for Internet network congestion control

This paper presents an active queue management (AQM) scheme based on sliding mode control (SMC) in order to solve the problem of congestion control in TCP communication. First, sliding mode observer is designed for input delay network system, a sufficient condition is given for the existence of such an observer in terms of linear matrix inequality (LMI). Then, based on estimated system state, a controller is synthesized by using the SMC theory combined with the reaching law technique. Furthermore, the reachability problem is also discussed. The stability and robustness of the proposed control scheme are then validated for different network scenarios in MATLAB. Simulation results have confirmed that the proposed scheme outperforms traditional observer-based controller.