Optimal Contract Formulation for Mobile Edge Computing Task Offloading in Heterogeneous Networks Considering the Age of Information

Mobile edge computing (MEC) faces severe challenges in achieving efficient and timely task offloading in heterogeneous network environments. While existing contract-based approaches address incentive compatibility and resource coordination, many either ignore the constraints of age of information (AoI) or suffer from high computational complexity. This paper presents an AoI-guaranteed Optimal Contract (AOC) mechanism that jointly considers information freshness and asymmetric information in MEC systems. We design a three-tier heterogeneous network architecture with non-orthogonal multiple access to enable cooperative task offloading across multiple cells and enhance spectral efficiency. Instead of a model that requires extensive training and is difficult to analyze, our proposed AOC framework uses a lightweight block coordinate descent (BCD) algorithm to solve closed-form contract solutions while ensuring incentive compatibility and individual rationality. Simulation results show that the AOC mechanism significantly improves the utility and AoI performance of the MEC server compared with existing incentive-based methods. In addition, the analysis confirms the robustness and practical deployability of the proposed framework under different system conditions.