The congestion control for TCP network based on input/output saturation

In this paper, for the nonlinear dynamic model of TCP network with both input saturation and output saturation, the Backstepping controller is proposed. Firstly, because the saturation function isn't derivable, the smooth differentiable function is chosen to replace it. Secondly, the restriction of output is transformed into states saturation. Meanwhile, taking the disturbance into consider, the disturbance observer is designed. Then, the Backstepping controller is proposed. Finally, the simulation results show that the disturbance can be observed effectively.