Age of Information: An Introduction and Survey

We summarize recent contributions in the broad area of age information (AoI). In particular, we describe current state art design and optimization low-latency cyberphysical systems applications which sources send time-stamped status updates to interested recipients. These desire at recipients be as timely possible; however, this is typically constrained by limited system resources. AoI timeliness metrics present general methods evaluation analysis that are applicable a wide variety systems. Starting from elementary single-server queues, apply these range increasingly complex systems, including energy harvesting sensors transmitting over noisy channels, parallel server queueing networks, various single-hop multi-hop wireless networks. also explore how update related MMSE sampling, estimation control stochastic processes. The paper concludes with review efforts employ applications.