Modified Smith Predictor for Network Congestion Control

In this paper, a novel active queue management (AQM) control law using modified Smith predictor is proposed. The proposed method provides a stable response for a TCP flow dynamics which is highly oscillatory or unstable under practical conditions. The controller decouples the setpoint response from the load response. The proposed control scheme can track the desired buffer level and reject any additional load disturbance such as unknown buffer depletion rate. Simulation results show high performance for the setpoint response when the parameters of TCP flow dynamics are known