A stable adaptive PI controller for AQM

Abstract

Active queue management (AQM) mechanisms have been proposed to support end-to-end congestion control mechanisms of transmission control protocol (TCP) in TCP/IP networks. This paper introduces a new AQM based on a stable adaptive proportional-integral (SAPI) controller. SAPI adaptively adjusts the PI controller parameters based on estimated network parameters to improve the transient performance of a fixed-gain PI controller. We present the SAPI scheme in detail, and provide guidelines for the selection of its parameters. Through extensive simulations, we demonstrate that SAPI maintains satisfactory transient and steady-state performance independent of traffic loads, round trip propagation d..