在间歇链路和能量约束下优化年龄采样与路由
Age Optimal Sampling and Routing under Intermittent Links and Energy Constraints
AI总结：
本文提出了一种联合优化采样和路由的算法，以在间歇链路和能量约束下最小化信息年龄，通过分析发现高延迟或低可用性路由仍可能优化信息新鲜度。
摘要：
实际系统中的链路，如卫星-地面集成网络，表现出不同的延迟分布、间歇可用性和异质能耗特征。这些特征对维持及时且节能的状态更新提出了重大挑战。虽然链路可用性限制了可行的传输路由，但路由决策决定了实际的延迟和能耗。本文通过联合优化采样和路由决策来最小化单调、非线性的信息年龄（AoI）。所提出的模型纳入了关键系统特征，包括具有相关随机延迟的多条路由、随机链路可用性和路由依赖的能耗。我们将问题建模为一个无限时间 horizon 的约束半马尔可夫决策过程（CSMDP），并开发了一个高效的嵌套算法，称为 Bisec-ReaVI，以解决此问题。我们分析了解决方案的结构特性，并揭示了联合最优策略结构：（i）对于一般的单调惩罚函数，最优采样策略是一种分段线性的等待策略，给定 N 条路由时最多有 N 个断点；（ii）在推导出的期望惩罚排序条件下，最优路由策略是一种单调阈值基于的手动策略，其特征是最多有 \binom{N}{2} 个阈值。在卫星-地面集成路由场景中的数值实验表明，所提出的方案有效地平衡了能耗和信息新鲜度，并揭示了一个反直觉的见解：即使具有更高平均延迟、更高延迟方差或更低可用性的路由，仍然可能在最小化 AoI 的单调函数中发挥关键作用。
英文摘要：
Links in practical systems, such as satellite--terrestrial integrated networks, exhibit distinct delay distributions, intermittent availability, and heterogeneous energy costs. These characteristics pose significant challenges to maintaining timely and energy-efficient status updates. While link availability restricts feasible transmission routes, routing decisions determine the actual delay and energy expenditure. This paper tackles these challenges by jointly optimizing sampling and routing decisions to minimize monotonic, non-linear Age of Information (AoI). The proposed formulation incorporates key system features, including multiple routes with correlated random delays, stochastic link availability, and route-dependent energy consumption. We model the problem as an infinite-horizon Constrained Semi-Markov Decision Process (CSMDP) with a hybrid state--action space and develop an efficient nested algorithm, termed Bisec-\textsc{ReaVI}, to solve this problem. We analyze the structural properties of the solution and reveal a well-defined jointly optimal policy structure: (i) For general monotonic penalty functions, the optimal sampling policy is a piecewise linear waiting policy with at most $N$ breakpoints given $N$ routes; and (ii) under a derived Expected Penalty Ordering condition, the optimal routing policy is a monotonic threshold-based handover policy characterized by at most $\binom{N}{2}$ thresholds. Numerical experiments in a \textit{satellite--terrestrial} integrated routing scenario demonstrate that the proposed scheme efficiently balances energy usage and information freshness, and reveal a counter-intuitive insight: \textit{even routes with higher average delay, higher delay variance or lower availability can still play a critical role in minimizing monotonic functions of AoI}.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
