Abstract-Age of information is a newly proposed metric that captures delay from an application layer perspective. The age measures the amount of time that elapsed from the moment the mostly recently received update was generated until the present time. In this paper, we study an age minimization problem over a wireless broadcast network with many users, where only one user can be served at a time. We formulate a Markov decision process (MDP) to find dynamic transmission scheduling schemes, with the purpose of minimizing the long-run average age. While showing that an optimal scheduling algorithm for the MDP is a simple stationary switch-type, we propose a sequence of finitestate approximations for our infinite-state MDP and prove its convergence. We then propose both optimal off-line and online scheduling algorithms for the finite-approximate MDPs, depending on knowledge of time-varying arrivals. Ideas of traditional networks have been focused on network throughput or delay. In addition to those concerns, in recent years there has been growing interest in an age of information. The age is defined to capture the freshness of information; more precisely, it is the time elapsed since the generation of the information. This is motivated by a variety of network applications requiring timely information, e.g., traffic, transportation, air quality, and typhoon. While the packet delay is usually referred to as the elapsed time from the generation to its delivery, the age includes not only the packet delay but the inter-delivery time because the age of information increases until the information is updated. We hence need to jointly consider the two parameters so as to design an age-optimal network. Moreover, while traditional relays need to keep all packets that are not served yet, the relays for the timely information only store the latest information, but remove those out-of-date packets, i.e. a new arrival always replaces the old packet in a buffer. Due to the distinctions, we need to re-consider networks for the timely information. In resource-shared networks, the scheduling is a critical issue to optimize network performance. For delivering clean theoretical results and clear engineering insights, we look at the simplest and fundamental problem by considering a
Optimizing the scheduling decisions in an AoI system multiple receivers is also investigated in REF , focusing on a perfect transmission medium, and an optimal scheduling algorithm for the MDP is shown to be thresholdtype.
Age of information: Design and analysis of optimal scheduling algorithms
2017 IEEE International Symposium on Information Theory (ISIT)
2017 IEEE International Symposium on Information Theory (ISIT)
Computer Science