Reconfigurable Intelligent Surface Assisted UAV-MCS Based on Transformer Enhanced Deep Reinforcement Learning

Mobile crowd sensing (MCS) is an emerging paradigm that enables participants to collaborate on various sensing tasks. UAVs are increasingly integrated into MCS systems to provide more reliable, accurate and cost-effective sensing services. However, optimizing UAV trajectories and communication efficiency, especially under non-line-of-sight (NLoS) channel conditions, remains a significant challenge. This paper proposes TRAIL, a Transformer-enhanced deep reinforcement Learning (DRL) algorithm. TRAIL aims to jointly optimize UAV trajectories and Reconfigurable Intelligent Surface (RIS) phase shifts to maximize data throughput while minimizing UAV energy consumption. The optimization problem is modeled as a Markov Decision Process (MDP), where the Transformer architecture captures long-term dependencies in UAV trajectories, and these features are input into a Double Deep Q-Network with Prioritized Experience Replay (PER-DDQN) to guide the agent in learning the optimal strategy. Simulation results demonstrate that TRAIL significantly outperforms state-of-the-art methods in both data throughput and energy efficiency.