Application of IMC-Smith Controller in the Large-Delay Network Congestion Control

At present, the transmission delay of network brings disadvantages to network congestion control, and the existent algorithms depend on exactitude model excessively. Therefore, a new delay expiration controller is proposed. The controller is used in the active queue management (AQM) algorithm. The new controller combines inner mode controller (IMC) and Smith estimate controller of control theory to AQM algorithm. The new algorithm can compensate time delay beforehand, so it could control the network congestion in time. The stability and robustness of network system can be ensured by the new algorithm under the condition of the parameter changing in a wide range. The simulation results of the algorithm under different conditions show the superiority of the IMC-Smith AQM algorithm