We consider a star-topology wireless network for status update where a central node collects status data from a large number of distributed machine-type terminals that share a wireless medium. The Age of Information (AoI) minimization scheduling problem is formulated by the restless multi-armed bandit. A widely-proven near-optimal solution, i.e., the Whittle’s index, is derived in closed-form and the corresponding indexability is established. The index is then generalized to incorporate stochastic, periodic packet arrivals and unreliable channels. Inspired by the index scheduling policies which achieve near-optimal AoI but require heavy signaling overhead, a contention-based random access scheme, namely Index-Prioritized Random Access (IPRA), is further proposed. Based on IPRA, terminals that are not urgent to update, indicated by their indices, are barred access to the wireless medium, thus improving the access timeliness. A computer-based simulation shows that IPRA’s performance is close to the optimal AoI in this setting and outperforms standard random access schemes. Also, for applications with hard AoI deadlines, we provide reliable deadline guarantee analysis. Closed-form achievable AoI stationary distributions under Bernoulli packet arrivals are derived such that AoI deadline with high reliability can be ensured by calculating the maximum number of supportable terminals and allocating system resources proportionally.

中文翻译：

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用于及时状态更新的封闭式 Whittle 索引随机访问

我们考虑用于状态更新的星形拓扑无线网络，其中中央节点从共享无线介质的大量分布式机器类型终端收集状态数据。信息时代 (AoI) 最小化调度问题由不安分的多臂老虎机制定。一个经过广泛证明的近最优解，即惠特尔指数，以封闭形式导出，并建立了相应的可索引性。然后将该指数概括为包含随机的、周期性的数据包到达和不可靠的信道。受索引调度策略的启发，该策略实现了接近最优的 AoI 但需要大量信令开销，进一步提出了一种基于竞争的随机接入方案，即索引优先随机接入（IPRA）。基于IPRA，不急于更新的终端，由其索引指示，禁止访问无线介质，从而提高访问时效性。基于计算机的模拟显示 IPRA 的性能接近此设置中的最佳 AoI，并且优于标准随机访问方案。此外，对于具有严格 AoI 截止日期的应用程序，我们提供可靠的截止日期保证分析。推导出伯努利分组到达下可实现的闭式AoI平稳分布，通过计算可支持终端的最大数量和按比例分配系统资源，确保具有高可靠性的AoI时限。对于具有严格 AoI 截止日期的应用程序，我们提供可靠的截止日期保证分析。推导出伯努利分组到达下可实现的闭式AoI平稳分布，通过计算可支持终端的最大数量和按比例分配系统资源，确保具有高可靠性的AoI时限。对于具有严格 AoI 截止日期的应用程序，我们提供可靠的截止日期保证分析。推导出伯努利分组到达下可实现的闭式AoI平稳分布，通过计算可支持终端的最大数量和按比例分配系统资源，确保具有高可靠性的AoI时限。