On the Minimum Achievable Age of Information for General Service-Time Distributions
This work addresses a foundational theoretical problem in networked systems for researchers and engineers, offering insights into data freshness optimization, but it is incremental as it builds on prior AoI research.
The paper tackles the fundamental problem of determining the minimum achievable Age of Information (AoI) in single-server-single-source queuing systems for any service-time distribution, showing that a fixed-threshold policy is optimal and providing conditions for when preemptions are beneficial.
There is a growing interest in analysing the freshness of data in networked systems. Age of Information (AoI) has emerged as a popular metric to quantify this freshness at a given destination. There has been a significant research effort in optimizing this metric in communication and networking systems under different settings. In contrast to previous works, we are interested in a fundamental question, what is the minimum achievable AoI in any single-server-single-source queuing system for a given service-time distribution? To address this question, we study a problem of optimizing AoI under service preemptions. Our main result is on the characterization of the minimum achievable average peak AoI (PAoI). We obtain this result by showing that a fixed-threshold policy is optimal in the set of all randomized-threshold causal policies. We use the characterization to provide necessary and sufficient conditions for the service-time distributions under which preemptions are beneficial.