Air-Ground Integrated Low-Energy Federated Learning for Secure 6G Communications

Federated learning(FL)is a distributed machine learning approach that could provide secure 6G communications to preserve user privacy.In 6G communications,unmanned aerial vehicles(UAVs)are widely used as FL parameter servers to collect and broadcast related parameters due to the advantages of easy deployment and high flexibility.However,the challenge of limited energy restricts the populariza⁃tion of UAV-enabled FL applications.An airground integrated low-energy federated learning framework is proposed,which minimizes the overall energy consumption of application communication while maintaining the quality of the FL model.Specifically,a hierarchical FL framework is proposed,where base stations(BSs)aggregate model parameters updated from their surrounding users separately and send the aggregated model parameters to the server,thereby reducing the energy consumption of communication.In addition,we optimize the deploy⁃ment of UAVs through a deep Q-network approach to minimize their energy consumption for transmission as well as movement,thus improv⁃ing the energy efficiency of the airground integrated system.The evaluation results show that our proposed method can reduce the system en⁃ergy consumption while maintaining the accuracy of the FL model.