Robust control for TCP network systems with input delay

In this paper, the robust control problem is studied based on a previously developed nonlinear dynamic model of TCP. By using Lyapunov-Krasovskii stability theory, a state feedback controller is designed to guarantee that the system could be robust asymptotically stable. Firstly, the packet-dropping probability is considered as an input, by linearizing the interconnection of TCP, an uncertain system with input delay is obtained. And then, by a state transformation, the original input-delayed system is converted into a state-delayed system. For the novel TCP network mode, the Lyapunov-Krasovskii function is defined, and the TCP network system can be asymptotically stabilized with the obtained state feedback control law by using Linear Matrix Inequalities (LMIs) approach. Finally, theory analysis and simulation results show the effectiveness of the derived control strategy and superiorities compared with the existing results.