Cloud-Edge-Client Collaborative Learning in Digital Twin Empowered Mobile Networks

Digital twin (DT) has emerged as a key enabler for the intelligent-oriented evolution of mobile networks. With the rise of privacy concerns for enabling intelligent applications in DT-empowered mobile networks (DTMNs), federated learning has garnered wide attention due to its potential on breaking down data silos. However, the data privacy of federated learning is greatly threatened by emerging gradient leakage attacks, and the need for frequent knowledge exchange limits its training efficiency over resource-constrained DTMNs. To circumvent such dilemmas, this work first proposes a privacy-enhanced federated learning framework based on cloud-edge-client collaborations. Particularly, model splitting between clients and edge servers makes gradient leakage attacks computationally prohibitive, and cloud-side partial model aggregation provides hierarchical data utility. To improve the training efficiency of the proposed learning framework, we further establish its communication and computation cost models, and develop a DT-assisted multi-agent deep reinforcement learning-based resource scheduler for joint client association and channel assignment. Finally, as a case study of intelligent applications in DTMNs, a human-robot collaborative nursing task is designed to evaluate the practical performance of our proposed scheduler. Experimental results show its superiority in saving training costs and preserving learning accuracy.