Queue Control Under Time-Variant Delays: A Discrete Time System Approach

This paper introduces a discrete time model for time-variant delays and investigates the very nature of such a delay. It is shown that a linear system-delay interface is a system theoretic necessity for the construction of composite linear systems with time-variant delays. Based on this analysis, two interfaces of particular importance are presented and used to obtain new, simple to check stability results for queue control systems. The relevance of the presented modeling and stability results on queue control systems to QoS control in modern communication networks is illustrated via several examples.