I. Introduction
With the growing development of Internet of Things (IoT), mobile edge computing (MEC) is enabled to leverage powerful computing capabilities at an edge server for processing compute-intensive tasks offloaded by IoT nodes. The MEC-IoT is widely applied to a large number of applications, such as smart grids [1], intelligent transportation systems [2], and metaverse [3]. The IoT nodes upload their data to the edge server in which machine learning is used to train the IoT data. Nevertheless, this source data offloading is vulnerable to wireless attacks, such as eavesdropping [4], [5], denial of service [6], or blackhole attacks [7]. To avoid possible data privacy leakage, federated learning is studied to train a global shared model at the edge server, which aggregates local model updates instead of original training data of the IoT nodes.