AQM controller design for IP routers supporting TCP flows based on pole placement
Q. Chen, Ou Yang · IEE Proceedings - Communications · 2004
The simple pole placement technique in classical control theory is exploited to propose two kinds of controllers for active queue management (AQM) in IP routers: the proportional controller based on pole placement (P_PP controller) and the proportional-plus-integral controller based on pole placement (PI_PP controller). The damping ratio ξ and the undamped natural frequency ωn are appropriately chosen such that the transient response of the system is satisfied and all the poles lie in the left-half s-plane to guarantee the stability of the system. The authors verify the effectiveness of the controllers via extensive simulations using OPNET, including the case of different time-varying round-trip times (RTTs) for different connections. Simulation results show that choosing appropriate values of ξ and ωn can successfully satisfy the transient response of the system. The impact of different values of ξ and ωn on the system performance is also investigated.