On designing a proportional controller for AQM routers based on pole placement

This paper proposes a proportional controller based on pole placement (P_PP controller) for active queue management (AQM) in IP routers supporting TCP flows. The formal P_PP controller design algorithm is presented and justified. The transient response and stability of the system are guaranteed by appropriately choosing damping ratio ζ. We verify the effectiveness of the P_PP controller through simulations using OPNET modeler. The simulation results show that choosing appropriate ζ can successfully satisfy the transient response of the system. The impacts of different values of ζ on the system performance are also investigated.