Novel AQM algorithm employing observer-based SMC for efficient internet congestion prevention

An active queue management (AQM) scheme employing state observer and sliding mode control (SMO-SMC) is designed in this paper in order to overcome congestion problem in TCP communication networks. 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. Then, on the grounds of estimated system state vector, a controller is synthesized by using the sliding-mode control theory combined with the reaching law technique. The reachability condition in such a SMO-SMC AQM scheme is also discussed. The stability and robustness of the proposed control scheme are then validated for different network scenarios using Matlab/Simulink. Simulation results for the single-bottleneck benchmark network confirmed the proposed scheme achieves high-quality performance as well as outperforms the previous observer-based sliding-mode and traditional controllers.