AI 中文总结
该研究针对LEO卫星辅助的能量采集物联网网络，采用先探测后传输机制，结合球形随机几何与半马尔可夫分析推导时间平均AoI，发现探测可降低AoI。
AI 中文摘要
我们使用信息年龄（Age of Information, AoI）指标分析低地球轨道（Low Earth Orbit, LEO）卫星辅助的能量采集物联网网络中状态更新传输的时效性。地面信源采集环境能量，通过LEO卫星向远程目的地发送状态更新。由于卫星移动性，信源到卫星的连接在开启和关闭时段交替，时段持续时间取决于卫星-地面几何关系。信源先验未知连接状态，因此采用“先探测后传输”机制：它先消耗1个能量单元感知卫星可用性，仅在探测成功后才传输更新。我们结合球形随机几何与半马尔可夫分析，刻画卫星连接与信源能量缓冲的耦合演化，推导时间平均AoI的解析表达式。随后，我们通过用长期开启状态概率替代能量过程中的瞬时连接状态，开发出复杂度更低的近似方法；当能量约束较弱或卫星连接高度间歇性时，该近似精度较高。数值结果表明，与盲目传输相比，探测可通过避免在关闭时段消耗能量，大幅降低AoI，尤其在卫星部署稀疏、解码要求严格或能量采集有限的情况下效果显著。
英文摘要
We analyze the timeliness of status-update delivery in a low Earth orbit (LEO) satellite-assisted energy-harvesting Internet of Things network using the Age of Information (AoI) metric. A ground source harvests ambient energy and sends status updates to a remote destination through LEO satellites. Because of satellite mobility, source-to-satellite connectivity alternates between on and off periods whose durations depend on the satellite-ground geometry. The source does not know the connectivity state a priori and therefore employs a probe-before-transmission mechanism: it first expends one energy unit to sense satellite availability and transmits an update only after a successful probe. We combine spherical stochastic geometry with semi-Markov analysis to characterize the coupled evolution of satellite connectivity and the source energy buffer, and derive an analytical expression for the time-average AoI. We then develop a lower-complexity approximation by replacing the instantaneous connectivity state in the energy process with the long-term on-state probability. The resulting approximation is accurate when the energy constraint is weak or satellite connectivity is highly intermittent. Numerical results show that probing can substantially reduce AoI relative to blind transmission by preventing energy expenditure during off periods, particularly under sparse satellite deployment, stringent decoding requirements, or limited energy harvesting.
Comments13 pages, 11 figures.This work has been submitted to the IEEE for possible publication
