Congestion control based on backstepping approach

The nonlinear transmission control protocol (TCP) dynamic model in the domain of Internet congestion control is considered in this paper. An observer is designed to estimate the unmeasured state. By applying the backstepping recursive technique and Lyapunov direct method, a kind of Active Queue Management (AQM) algorithm is designed to asymptotically stabilize the closed-loop system through output feedback. Simulation results show that the system has desired steady state performance including less tuning time, lower packet loss rate, higher link utilization than the traditional Random Early Detection (RED) or Proportional Integral (PI) algorithms, and robust quality under varying network environment.