Design of H� Congestion Controller for TCP Networks Based on LMI Formulation


1 Assistant Professor, Faculty of Electrical, Biomedical and Mechatronic Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran

2 MSc, Faculty of Electrical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran


In this paper, a state feedback H¥ controller is proposed in order to design an active queue management (AQM) system based on congestion control algorithm for networks supporting TCP protocols. In this approach, the available link bandwidth is modeled as a time-variant disturbance. The purpose of this paper is to design a controller which is capable of achieving the queue size and can guarantee asymptotic stability in the presence of disturbance. An important feature of the proposed approach is that the performance of system, including the disturbance rejection and stability of closed-loop system, are guaranteed for all round-trip times that are less than a known value. The controller design is formulated in the form of some linear matrix inequalities, which can be efficiently solved numerically. The simulation results demonstrate the effectiveness of the proposed methods in comparison with the conventional methods.


Bertsekas, D. and Gallager, R.G. (1992). Data Networks. Upper Saddle River, NJ, Prentice-Hall.
Cavendish, D., Gerla, M., and Mascolo, S. (2004). A control theoretical approach to congestion control in packet networks. IEEE/ACM Transactions on Networking, 893-906.
Chen, Q. and Yang, O.W. (2005). Design of AQM controller for IP routers based on H1 S/U MSP. Proceeding of IEEE intern. conf. on communications, 340-344.
Chen, Q., and Yang, O.W. (2007). Robust controller design for AQM router.  IEEE Transactions on Automatic Control, 938-943.
Clark, DD. and Fang, W. (1998). Explicit allocation of best effort packet delivery service. IEEE/ACM Transactions on Networking, 362-73.
Fan, X., Arcak, M., and Wen, J.T. (2004). Robustness of network flow control against disturbances and time-delay. Systems and Control Letters, 13-29.
Floyd, S. and Jacobson, V. (1997). Random early detection gateways for congestion avoidance. IEEE/ACM Transactions on Networking,  1-22.
Fridman, E. and Shaked, U. (2001). New bounded real lemma representations for timedelay systems and their applications. IEEE Transactions on Automatic Control, 1973-1979.
Hollot, C.V., Misra, V., Towsley, D. and Gong, W.B. (2001). On designing improved controllers for AQM routers supporting TCP lows. Proceedings of the IEEE INFOCOM, Alaska, USA, 1726-1734.
Hollot, C.V., Misra, V., Towsley, D. and Gong, W.B. (2002). Analysis and design of controllers for AQM routers supporting TCP flows. IEEE Transactions on Automatic Control, 945-959.
Kim, K.B. (2006). Design of feedback controls supporting TCP based on the state-space approach. IEEE Transactions on Automatic Control, 1086-99.
Lee, Y.S., Kwon, W.H. and Park, P.G. (2007). Authors reply: Comments on delay-dependent robust H1 control for uncertain systems with a state-delay.  Automatica, 572-573.
Lin, D. and Morris, R. (1997). Dynamics of random early detection.  Proceedings of the ACM SIGCOM’97, Cannes, 127-137.
Mascolo, S. (1999). Congestion control in high-speed communication networks using the Smith principle. Automatica, 1921-1935.
Misra, V., Gong, W.B. and Towsley, D. (2000). Fluid-based analysis of a network of AQM routers supporting TCP flows with an application to RED. Proceedings of the ACM/SIGCOM, Stockholm, 151-160.
Qtt, T.J. , Lakshman, T.V. and Wong, L.H. (1999). SRED: Stabilized RED. Proceedings of the IEEE INFOCOM’99, New York, 1346-1355.
Quet, P.F. and Özbay, H. (2004). On the design of AQM supporting TCP flows using robust control theory. IEEE Transactions on Automatic Control, 49, 1031-1036.
Ren, F.Y., Lin, C. and Yin, X.H. (2005). Design a congestion controller based on sliding mode variable structure control. Computer Communications, 1050-1061.
Shaked, U., Yaesh, I. and De Souza, C. (1998). Bounded real criteria for linear timedelay systems. IEEE Transactions on Automatic Control, 1016-1022.
Yang, F., Wang, Z., Hung, Y.S. and Gani, M. (2006). H1 control for networked systems with random communication delays. IEEE Transactions on Automatic Control, 511-518.