Hierarchical Deep Reinforcement Learning with Information Freshness in Smart Agriculture Applications

In precision farming, timely information is vital for effective decision-making in irrigation and pest control processes. Unmanned Aerial Vehicles (UAVs) and Multi-access Edge Computing (MEC) servers optimize data collection from ground sensors. However, integrating sensors, controllers, and actuators complicates data freshness in closed-loop communication. Computational resource optimization is also crucial, especially in energy-constrained equipment and competitive resource scenarios. This work optimizes data freshness and task turnaround time (TAT) with a UAV trajectory and MEC offloading strategy. Analysis includes assessing delays in uplink, downlink, and queues. This gains significance under dynamic network conditions and variable resources. A hierarchical deep reinforcement approach is proposed. Numerical results indicate the proposed solution outperforms baselines, improving data freshness by up to $31 \%$ and simultaneously decreasing TAT by $34 \%$.