Joint User Scheduling and Resource Allocation for Federated Learning over Wireless Networks

Federated learning (FL) is a decentralized algorithm that can train a globally shared model without the requirement to send the raw data to a centralized server by user equipments (UEs). Consider the UEs with non-independently and identically distributed (non-IID) data, heterogeneous computational capabilities and wireless channel conditions, FL becomes unproductive over a wireless network. In this paper, we jointly optimize the user scheduling policy and resource allocation to achieve a tradeoff among the fairness of user scheduling, the accuracy of FL, training time, and energy consumption of UEs. The optimization problem is formulated as a Markov Decision Process considering the potential impact of current scheduling on subsequent training and available resources. To solve the problem, a policy network is trained based on an actor-critic deep reinforcement learning framework. Simulation results show that the proposed user scheduling and resource allocation policy reduces the time and energy cost of the training process while improving the freshness of local update and performance on the 20% worst UEs compared with random user selection and resource allocation policy.