Federated learning (FL) plays an important role in the development of smart cities. With the evolution of big data and artificial intelligence, issues related to data privacy and protection have emerged, which can be solved by FL. In this paper, the current developments in FL and its applications in various fields are reviewed. With a comprehensive investigation, the latest research on the application of FL is discussed for various fields in smart cities. We explain the current developments in FL in fields, such as the Internet of Things (IoT), transportation, communications, finance, and medicine. First, we introduce the background, definition, and key technologies of FL. Then, we review key applications and the latest results. Finally, we discuss the future applications and research directions of FL in smart cities.

联邦学习 (FL) 在智慧城市的发展中发挥着重要作用。随着大数据和人工智能的演进，出现了与数据隐私和保护相关的问题，FL可以解决这些问题。本文回顾了 FL 的当前发展及其在各个领域的应用。通过全面调查，讨论了 FL 在智慧城市各个领域的应用的最新研究。我们解释了 FL 在物联网 (IoT)、交通、通信、金融和医学等领域的当前发展。首先，我们介绍了 FL 的背景、定义和关键技术。然后，我们审查关键应用程序和最新结果。最后，我们讨论了 FL 在智慧城市中的未来应用和研究方向。