Is proportional fair scheduling suitable for age-sensitive traffic?

Keywords Status update systems; Age of information; Peak age of information; Proportional fairness; Temporal fairness Abstract Proportional Fair (PF) scheduling with successful deployments in various cellular wireless networks and wireless LANs, aims at maximizing the sum of the logarithms of user throughputs. PF scheduling is known to strike an appropriate balance between fairness and throughput, for conventional data traffic. On the other hand, there has recently been a surge of interest in status update networks carrying age-sensitive traffic for which information freshness is crucial and therefore network performance metrics driven by Age of Information (AoI) are instrumental, as opposed to conventional performance metrics such as delay, loss, or throughput, used for conventional data traffic. This paper studies the scheduling problem for the downlink of a cellular wireless network with a transmitter sending age-sensitive status update packets from multiple information sources to users with the goal of keeping the information as fresh as possible for the users. For this purpose, under the generate-at-will scenario, an age-agnostic model-free scheduler is proposed with the goal of minimizing the weighted sum peak AoI of the network, which is the performance metric used in this paper for quantifying information freshness. With numerical examples, the proposed scheduler is compared and contrasted with weighted PF scheduling in terms of implementation and performance, in both non-opportunistic and opportunistic scenarios. Author Affiliation: Bilkent University, Electrical and Electronics Engineering Department, Bilkent, 06800, Ankara, Turkey * Corresponding author. Article History: Received 9 October 2022; Revised 10 February 2023; Accepted 28 February 2023 Byline: Nail Akar [akar@ee.bilkent.edu.tr] (*), Ezhan Karasan