State-feedback constrained ℋ∞ control of active queue management

We propose a robust active queue management algorithm based on constrained ℋ_∞ control for the Internet system with large time-delay, complex variations and detrimental disturbances. In the approach, the available link bandwidth is modelled as a nominal constant value, which is known to the link, plus a time-variant disturbance, which is unknown. Considering the network constraints, the active queue management is converted to the disturbance attenuation problem of constrained systems. Then, the constrained ℋ_∞ control scheme is used to guarantee the disturbance attenuation performance of the congestion control system. The effectiveness of the proposed approach is verified via simulations in Matlab.