Design, validation and experimental testing of a Robust AQM Control

This paper is concerned with the design, the validation and the experimental testing of improved AQM control schemes to cope with unwanted variations of characteristic parameters such as the average round-trip time, the load and link capacity. An appropriate robust H$^{\infty}$ controller for time-delay systems is proposed and hence used to design a suitable AQM control scheme. A robust observer is used to estimate online the transmission window resulting in an output feedback stabilization scheme for AQM. The resulting control law is validated and tested firstly through numerical simulations in Network Simulator (NS-2) and then experimentally.