FedKT: Federated learning with knowledge transfer for non-IID data

Federated Learning enables clients to train a joint model collaboratively without disclosing raw data. However, learning over non-IID data may raise performance degeneration, which has become a fundamental bottleneck. Despite numerous efforts to address this issue, challenges such as excessive local computational burdens and reliance on shared data persist, rendering them impractical in real-world scenarios. In this paper, we propose a novel federated knowledge transfer framework to overcome data heterogeneity issues. Specifically, a model segmentation distillation method and a learnable aggregation network are developed for server-side knowledge ensemble and transfer, while a client-side consistency-constrained loss is devised to rectify local updates, thereby enhancing both global and client models. The framework considers both diversity and consistency among clients and can serve as a general solution for extracting knowledge from distributed nodes. Extensive experiments on four datasets demonstrate our framework’s effectiveness, achieving superior performance compared to advanced competitors in high-heterogeneity settings.