Personalized Federated Learning for Gradient Alignment
This work addresses the challenges in personalized federated learning arising from high local gradient variance due to heterogeneous and limited client data, as well as the distortion of personalized optimization directions during model aggregation. The authors propose pFLAlign, a novel framework that, for the first time, derives a gradient alignment mechanism from a PAC-Bayesian perspective. pFLAlign employs a two-stage strategy: it adaptively adjusts gradient directions during local training and re-aligns personalized directions after global aggregation to preserve client-specific information. This approach significantly enhances both personalization performance and training stability, achieving state-of-the-art results across multiple benchmarks. Ablation studies further confirm the effectiveness of each component in the proposed framework.