Adaptive Robust H∞ finite-time congestion control design for TCP/AQM Network System with parametric uncertainties

The congestion control problem is one of the most essential subjects in the Transmission Control Protocol (TCP) Network because of the complex nonlinear model, uncertainties, and external disturbances.  This paper extends the adaptive robust H∞ control finite-time approach to TCP network and presents a new solution to solve the congestion control problem employing Active Queue Management (AQM). Firstly, a modified nonlinear model of TCP network system with parametric uncertainties and external disturbance is given. Then, by several variable changes based on the backstepping method and Lyapunov function, adaptation and control laws were derived. Stability analysis is given to prove that all the signals of the closed-loop system are finite-time bounded. In addition, the results show that the proposed controller can guarantee both the transient and steady-state performance of the system, the queue of the TCP network system can track the desired queue and the disturbance is rejected satisfactory based on H∞ control part of the controller. Finally, a comparison example is considered to demonstrate the feasibility and superiority of the presented scheme.

Keywords:

adaptive control , Robust H∞ control , TCP/AQM , finite-time , parametric uncertainties