An AQM scheme based on Adaptive Weight Cascaded PID controller

In this paper we propose a new Active Queue Management (AQM) scheme based on Adaptive Weight Cascaded PID controller (AWCPID). The inputs of the outer and inner loop PID are queue length error, difference between packets arrival rate and export link capacity respectively. The ratio of outputs of the two PID controllers are dynamically adapted according to the magnitude of their inputs. An adaptive reference packets arrival rate, which is adapted based on network condition, is defined to give the controller more adaptivity. Simulations show that AWCPID can make queue lengths to converge quickly to the target and is effective in a wild range of network conditions. Its advantage over Single Neuron PID is also demonstrated extensively.