Age of Information in Multihop Connections With Tributary Traffic and No Preemption

• Published in: IEEE transactions on communications Vol. 70; no. 10; pp. 6718 - 6733
• Main Authors: Chiariotti, Federico, Vikhrova, Olga, Soret, Beatriz, Popovski, Petar
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Age; Analytical models; Computational modeling; delay systems; Internet of Things; Internet of Things (IoT); Lower bounds; Network topologies; Optimization; Preempting; Queueing; Queueing analysis; Routing; Satellites; Scheduling; Spread spectrum communication; telecommunication network topology; Traffic congestion; Traffic information
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2022.3202946

Age of Information (AoI) has gained significant attention from the research community because of its applications to Internet of Things (IoT) monitoring and control. In this work, we treat multihop connections over queuing networks with tributary flows and non-preemptive service: packets cannot be discarded because they are utilized for other system objectives, such as data analytics. Without preemption, the key tool for optimizing AoI is then the scheduling policy between the different data flows at each intermediate node. This is the subject of our analysis, along with the impact of packet erasure on the age. We derive upper and lower bounds for the average AoI considering several queuing policies in arbitrary network topologies, and present the results in different scenarios. Network topology, tributary traffic load, and link characteristics such as packet erasure generate complex trade-offs, which affect the optimal operation point and the age performance. The scheduling strategy at each node can also affect performance and fairness among users, particularly at critical bottleneck links, which have a significant impact on the overall performance of the whole network.