Design of Lyapunov based controllers as TCP AQM

The paper considers the design of robust AQM for the congestion problem of a router. Using a state space representation of a linearized fluid model of TCP, we provide an AQM which stabilises the queue length of the buffer for any delay less than a prescribed upper bound. Our results rely on the use of recently developed Lyapunov-Krasovskii functional and have been expressed in terms of Linear Matrix Inequalities which can be solved easily. Finally, an example extracted from the literature and simulations support our study.