Title :
A robust nonlinear PI controller for improving AQM performance
Author :
Chang, Xiaolin ; Muppala, Jogesh K. ; Yu, Jen-te
Author_Institution :
Dept. of Comput. Sci., Hong Kong Univ. of Sci. & Technol., Kowloon, China
Abstract :
In this paper a simple robust proportional-integral (R-PI) controller is proposed for active queue management (AQM). We assume that TCP/AQM dynamics can be described by the linearized TCP/AQM model (C. V. Hollot et al., April 2001). R-PI aims to address the tradeoff between responsiveness and stability and the tradeoff between responsiveness and high link utilization over a large range of structured and unstructured uncertainties. This controller achieves these goals by varying its control parameters according to the system state. We show that the closed-loop system is asymptotically stable as long as the control parameters are time-invariant and varying in a range. Extensive simulation results demonstrate the robust ability of R-PI compared with some other AQM mechanisms in the literature.
Keywords :
Internet; PI control; asymptotic stability; closed loop systems; computer network management; nonlinear control systems; queueing theory; robust control; telecommunication control; telecommunication links; time-varying systems; transport protocols; AQM performance; TCP/AQM dynamic; active queue management; closed-loop system; proportional-integral controller; robust nonlinear PI controller; time-invariant; Automatic control; Control systems; Delay; PD control; Pi control; Proportional control; Quality of service; Robust control; Stability; Uncertainty;
Conference_Titel :
Communications, 2004 IEEE International Conference on
Print_ISBN :
0-7803-8533-0
DOI :
10.1109/ICC.2004.1312922