Constraint-Aware Resource Exploration for Multi-Agent Collaborative Offloading in Mobile Edge Computing

Mobile edge computing (MEC) supports computation-intensive and latency-sensitive Internet of Things (IoT) applications. However, collaborative task offloading in dynamic heterogeneous environments remains challenging due to coupled physical constraints, shared resource competition, and high-dimensional decision spaces. Existing multi-agent deep reinforcement learning (MADRL) approaches often rely on static penalties or centralized action truncation for constraint handling. These methods may lead to unstable training, conservative strategies, and limited collaboration. To address these limitations, this paper proposes a constraint-aware multi-agent edge collaborative offloading algorithm (CARE-CTDE). The offloading problem is formulated as a constrained Markov decision process and addressed under a centralized training and decentralized execution (CTDE) framework. Dynamic Lagrange multipliers replace fixed penalties to improve training stability and support smoother exploration near constraint boundaries. A multi-threshold-guided Lagrangian constraint regulation mechanism further coordinates heterogeneous constraints, including energy consumption, latency, and server capacity. In addition, a congestion-driven cost allocation method transforms global resource competition into dynamic cost signals, guiding agents toward more coordinated offloading decisions. The simulation results show that CARE-CTDE achieves better scheduling performance, resource utilization, and constraint satisfaction than baseline methods in dynamic heterogeneous MEC scenarios, demonstrating its effectiveness and robustness for constrained edge computing systems.