标准的机器学习方法需要在数据中心集中训练数据，从而采用集中式机器学习算法来进行数据分析和推理。然而，由于无线网络中的隐私限制以及无线通信资源受限，边缘设备将数据传输到参数服务器通常是不可取和不切实际的。联邦学习可解决这些问题。联邦学习可以使设备能够在没有数据共享和传输的情况下训练机器学习模型。本文全面概述了未来第六代（6G）无线网络的联邦学习应用。特别是，首先描述了将联邦学习应用于无线通信中的基本要求。然后详细介绍了无线通信中潜在的联邦学习新型应用，讨论了与新型应用相关的主要问题和挑战。最后，描述了用于无线通信的联邦学习的详细实现方案，并给出了联邦学习的难点和应用前景。

Standard machine-learning approaches involve the centralization of training data in a data center, where centralized machine-learning algorithms can be applied for data analysis and inference. However, due to privacy restrictions and limited communication resources in wireless networks, it is often undesirable or impractical for the devices to transmit data to parameter sever. One approach to mitigate these problems is federated learning (FL), which enables the devices to train a common machine learning model without data sharing and transmission. This paper provides a comprehensive overview of FL applications for envisioned sixth generation (6G) wireless networks. In particular, the essential requirements for applying FL to wireless communications are first described. Then potential FL applications in wireless communications are detailed. The main problems and challenges associated with such applications are discussed. Finally, a comprehensive FL implementation for wireless communications is described.