In this paper, the wireless hierarchical federated learning (HFL) is revisited by considering physical layer security (PLS). First, we establish a framework for this new problem. Then, we propose a practical finite blocklength (FBL) coding scheme for the wireless HFL in the presence of PLS, which is self-secure when the coding blocklength is lager than a certain threshold. Finally, the study of this paper is further explained via numerical examples and simulation results.

翻译：本文考虑物理层安全，重新审视了无线分层联邦学习问题。首先，我们为此新问题建立了一个框架。随后，针对存在物理层安全的无线分层联邦学习，提出了一种实用的有限分组长度编码方案，当编码分组长度超过一定阈值时，该方案具有自安全特性。最后，通过数值示例和仿真结果进一步阐释了本文的研究内容。