Toward Sustainable Low-Carbon IoT for 6G: Green Energy-Charged WPCN

The upcoming sixth-generation (6G) communication system requires to deploy a high density of Internet-of-Things devices (IoTDs) to enable comprehensive perception and sustainable data transmission, which poses challenges in powering and maintaining the batteries of numerous low-power IoT devices, especially in harsh, toxic, and radioactive environments. Moreover, as the world strives towards carbon neutrality, realizing sustainable and low-carbon 6G networks has become imperative. To satisfy these important and stringent requirements, a green energy charged wireless powered communication network (GreenWPCN) paradigm is proposed as a transformative solution. This framework integrates wireless power transfer (WPT) and green energy harvesting (GEH), successfully inheriting the controllability of WPT and the sustainability of GEH. To empower researchers to systematically grasp GreenWPCN and seamlessly incorporate it into upcoming 6G networks, this article provides a comprehensive overview of this paradigm. Specifically, we first introduce the concept of this paradigm and present its four representative models, and then analyze key challenges in optimally designing GreenWPCN systems. In addition, we build a practical experimental platform and present examples of design optimization. Finally, several promising future research directions on GreenWPCN are discussed.