An LMI Approach to Robust Control of Packet Loss Probability

Provisioning QoS enabled VPN services over packet switched networks is increasingly important for service providers. Previous works propose a dynamic packet loss control system that maintains preset packet loss targets for the instantiated VPN services in the provider´s backbone network. In the control system, the transducer and dynamic model have been studied. However, the identified linear model contains time-varying norm-bounded uncertain parameters. This paper extends the previous research and designs a robust controller. Specifically, the classical controller is first designed. A linear matrix inequality (LMI) approach for designing the robust proportional-integral (PI) controller is then studied. By adopting the LMI expression, a symmetric positive definite matrix P with guaranteed overall system´s quadratic stability is determined. The matrix P finally infers the robust PI controller parameters. Through a number of experiments, the transient and steady state performance of the controller-is evaluated on the live NCIT*net network