A robust active queue management scheme based on global sliding mode control

For the problem of transmission control protocol (TCP) network congestion control, on the basis of global sliding mode control, an active queue management (AQM) scheme adaptive to the change of dynamic network flow is presented. The proposed scheme can eliminate the reaching phase from conventional sliding mode control, and guarantee the system robustness during the whole control process. At the same time, it also shows its good transient and steady state responses in practical TCP/IP network systems, such as modeling uncertainties, input saturation, fluctuation of time-varying parameters and network jittering due to non-TCP sessions. Simulation results demonstrate that this scheme enables the queue length to converge to set value quickly and keeps the queue oscillation small, in particular, the scheme proposed outperforms the conventional PI control and sliding mode control when the network conditions change.