Stability analysis of congestion control of proportional TCP/AQM networks: A parameter space approach

This article presents a necessary and sufficient condition for the local stability of congestion control of proportional TCP/AQM networks via a parameter space approach. First, a small signal linearization of fluid-flow TCP congestion model is conducted about the operating point. Second, the linearized system is closed by the feedback of proportional AQM scheme, and based on the above-mentioned necessary and sufficient condition, the relationship between the proportional gain bound and the network parameters bounds (especially, the round-trip time delay bound) is analyzed. A kind of parameter optimization design of network control systems is given. Finally, simulation studies show that the result obtained in this article is less conservative than the previous one using the Lyapunov sufficient condition.