Output feedback H2 Control of multiple input delay systems with application to congestion control

This paper is concerned with the finite horizon output feedback H-2 control problem for discrete time systems with multiple input delays. A separation principle is applied which converts the H-2 control problem into an associated linear quadratic regulation (LQR) problem in conjunction with a Kalman filter. The H-2 output feedback controller is constructed by solving two Riccati difference equations (RDEs) of the same dimension as the plant (ignoring the delays), similar to the solution of the standard H-2 control problem. The output feedback H-2 control result is then applied to ATM congestion control. Simulations show that the proposed control technique can achieve desired control performance effectively and is robust to the varying round trip delay of the ATM network to some extent.