Age of Information in G/G/1/1 Systems: Age Expressions, Bounds, Special Cases, and Optimization

We consider the average age of information in G/G/1/1 systems under two service discipline models. In first model, if a new update arrives when is busy, it blocked; second preempts current service. For blocking we derive an exact expression for systems. Then, using systems, calculate expressions special cases, i.e., M/G/1/1 and G/M/1/1 observe that deterministic interarrivals minimize given mean interarrival time. Next, preemption similar to discipline, Average can be written as summation terms, which depends only on moments times rate. other words, are decoupled. prove optimum On hand, non-exponential optimal distribution relative values time Finally, propose simple upper bound discipline.