🤖 AI Summary
This study addresses the integration of satellite data into a multimodal remote monitoring system comprising terrestrial IoT devices, unmanned aerial vehicles (UAVs), and periodic satellites, specifically under high-latency and low-reliability conditions. The work proposes a graph-based spatial partitioning framework that synergistically combines fixed sensing, mobile coverage, and wide-area observation to optimize information freshness, quantified by weighted Age of Information (AoI). For the first time, it systematically evaluates the value of satellite observations in AoI-aware monitoring. By deriving a closed-form expression and a theoretical lower bound for weighted AoI, and integrating a maximum-weight scheduling policy, the paper reveals the fundamental scheduling dynamics in such heterogeneous multi-source systems. Simulations delineate the utility boundary of satellite data, offering theoretical grounding and actionable insights for real-world deployment.
📝 Abstract
We investigate a remote monitoring framework with multiple sensing modalities including IoT sensors on the ground, mobile UAVs in the air, and a periodically available satellite constellation. While the IoT sensors cover small areas and remain fixed, the UAVs can move between locations and cover larger areas, and the satellites can observe the entire region but have high latency and low reliability. We divide the deployment region into cells and model it as a graph, with the nodes representing individual cells and edges representing possible UAV mobility patterns. To evaluate the freshness of collected information from this graph, we adopt the Age of Information (AoI) metric, measured separately for each cell. Under a given deployment of IoT nodes and UAV mobility patterns, our objective is to ascertain whether the system should actually utilize monitoring updates from satellites - a seemingly simple yet surprisingly elusive question. For stationary randomized scheduling policies, we develop closed-form expressions and lower bounds for the weighted-sum AoI and utilize this analysis to explore performance tradeoffs as system parameters vary. We also provide a Lyapunov style max-weight policy and detailed simulations that provide crucial insights for deploying such systems in practice.