Few-Round Learning for Federated Learning

Federated learning (FL) presents an appealing opportunity for individuals who are willing to make their private data available for building a communal model without revealing their data contents to anyone else. Of central issues that may limit a widespread adoption of FL is the significant communication resources required in the exchange of updated model parameters between the server and individual clients over many communication rounds. In this work, we focus on limiting the number of model exchange rounds in FL to some small fixed number R, to control the communication burden. Following the spirit of meta-learning for few-shot learning, we take a meta-learning strategy to train the model so that once the meta-training phase is over, only R rounds of FL would produce a model that will satisfy the needs of all participating clients. A key advantage of employing meta-training is that the main labeled dataset used in training could differ significantly (e.g., different classes of images) from the actual data sample presented at inference time. Compared to the meta-training approaches to optimize personalized local models at distributed devices, our method better handles the potential lack of data variability at individual nodes. Extensive experimental results indicate that meta-training geared to few-round learning provide large performance improvements compared to various baselines.