Observer-Based Robust Controller Design for Active Queue Management

Abstract

In this paper, an observer–based controller is designed for the problem of congestion control. In TCP/IP networks, the packets-dropping probability function is considered as a control input. Therefore, the work described here is to design robust observer controller, which is aimed at robust stabilization of network system with uncertainties, input delay and a saturated input. The controller is used to estimate online the average trasmission window and achieve the desired queue length. By applying the Lyapunov-Krasovskii function approach and the linear matrix inequality technique, control law is derived. Simulation experiments have been carrier out and the results demonstrate this scheme can achieve transient and steady-state responses. The results also show that this scheme outperformance the tradition PI controller.