Personalized federated learning (PFL) enables customized models for clients with varying data distributions. However, existing PFL methods often incur high computational and communication costs, limiting their practical application. This paper proposes a novel PFL method, Class-wise Federated Averaging (cwFedAVG), that performs Federated Averaging (FedAVG) class-wise, creating multiple global models per class on the server. Each local model integrates these global models weighted by its estimated local class distribution, derived from the L2-norms of deep network weights, avoiding privacy violations. Afterward, each global model does the same with local models using the same method. We also newly designed Weight Distribution Regularizer (WDR) to further enhance the accuracy of estimating a local class distribution by minimizing the Euclidean distance between the class distribution and the weight norms' distribution. Experimental results demonstrate that cwFedAVG matches or outperforms several existing PFL methods. Notably, cwFedAVG is conceptually simple yet computationally efficient as it mitigates the need for extensive calculation to collaborate between clients by leveraging shared global models. Visualizations provide insights into how cwFedAVG enables local model specialization on respective class distributions while global models capture class-relevant information across clients.

个性化联邦学习中，通过使用分别适用于具有多样数据分布的客户端的定制模型。本文提出了一种新颖的PFL方法，即类别级联联邦平均（cwFedAVG），该方法在服务器端按类别执行联邦平均（FedAVG），创建多个每个类别的全局模型。每个本地模型使用其估计的本地类别分布（由深度网络权重的L2-范数导出），加权整合这些全局模型，避免了隐私违规。每个全局模型以相同的方法对本地模型进行操作。实验结果显示，cwFedAVG可以与多个现有的PFL方法相媲美甚至更好。值得注意的是，cwFedAVG在概念上简单而计算高效，通过利用共享全局模型来减少客户端之间合作所需的广泛计算。可视化结果揭示了cwFedAVG如何实现了各自类别分布上的本地模型专业化，同时全局模型捕获了跨客户端的类别相关信息。

针对个性化联邦学习的客户正则化和类别分布聚合