A time-delay system approach to congestion control system designed for time-delay networks

A time-delay system approach is proposed to design the congestion control system for the time-delay networks using AQM routers. The single-link congestion control system is modeled as an uncertain linear time-delay system with input delay by using the state-space-model method. The state feedback controller is considered, and by applying the Lyapunov theory and the linear matrix inequality approach, we had sufficient exponential stability conditions derived for the resulting closed-loop congestion control system. Design procedures involve an iterative algorithm which is also proposed to design desired congestion controllers. The designed controllers guarantee that the actual queue length of the network bottleneck track the reference value with a certain exponential rate, and thus achieve the congestion control purpose. An illustrative example is finally given to demonstrate the effectiveness of the proposed results.