I. Introduction
Thanks to the rapid rise of the Internet of Things, there are increasing demands and novel user scenarios for human life. Smart appliances [1], autonomous driving [2], intelligent robots [3] are exemplar applications with a considerable number of devices connected to each other. For industry, wireless communications and artificial intelligence (AI) jointly promote the development of IIoT [4], [5]. In particular, IIoT has been witnessed to significantly improve manufacturing efficiency, reduce product cost, and upgrade the manufacturing process by integrating various sensors and controllers with intelligent analysis. While the intelligence in IIoT is the core component that leads to the abovementioned benefits, a critical part behind the scene is the abundance of the data.