Age of information is a new network performance metric that captures the freshness of information at end-users. This paper studies the age of information from a scheduling perspective. To that end, we consider a wireless broadcast network where a base-station (BS) is updating many users on random information arrivals under a transmission capacity constraint. For the offline case when the arrival statistics are known to the BS, we develop a structural MDP scheduling algorithm and an index scheduling algorithm, leveraging Markov decision process (MDP) techniques and the Whittle's methodology for restless bandits. By exploring optimal structural results, we not only reduce the computational complexity of the MDP-based algorithm, but also simplify deriving a closed form of the Whittle index. Moreover, for the online case, we develop an MDP-based online scheduling algorithm and an index-based online scheduling algorithm. Both the structural MDP scheduling algorithm and the MDP-based online scheduling algorithm asymptotically minimize the average age, while the index scheduling algorithm minimizes the average age when the information arrival rates for all users are the same. Finally, the algorithms are validated via extensive numerical studies.

中文翻译：

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在随机到达的无线广播网络中最小化信息年龄的调度算法

信息时代是一种新的网络性能指标，可捕获最终用户信息的新鲜度。本文从调度的角度研究信息时代。为此，我们考虑一个无线广播网络，其中基站 (BS) 在传输容量约束下根据随机信息到达更新许多用户。对于 BS 知道到达统计数据的离线情况，我们开发了结构 MDP 调度算法和索引调度算法，利用马尔可夫决策过程 (MDP) 技术和 Whittle 的无休止强盗方法。通过探索最优结构结果，我们不仅降低了基于 MDP 算法的计算复杂度，而且简化了 Whittle 指数的封闭形式的推导。此外，对于在线案例，我们开发了基于MDP的在线调度算法和基于索引的在线调度算法。结构MDP调度算法和基于MDP的在线调度算法都是渐近最小化平均年龄，而索引调度算法在所有用户的信息到达率相同的情况下最小化平均年龄。最后，这些算法通过广泛的数值研究得到验证。