A robust active queue management scheme for network congestion control

摘要

Active queue management has been proved to be an effective mechanism at the intermediate nodes to alleviate network congestion. A novel robust active queue management scheme based on H-infinity feedback control theory is proposed in this paper. A TCP model with link capacity disturbances, modeling uncertainties and time-varying delay is investigated, and the objective is to design a feedback controller which guarantee the queue length stability and robustness against the external disturbances and model perturbations. Meanwhile a simple on-line estimation of TCP window size is adopted instead of state observer which reduces computation burden significantly. The controller parameters are obtained through the standard linear matrix inequality techniques. Finally NS-2 simulation results demonstrate effectiveness of the proposed method.