Spectrum Sharing for Ambient Internet-of-Things: Principle, Applications and Open Issues

The Internet of Things (IoT) has garnered considerable attention in recent years due to its ability to connect diverse devices, enabling intelligent identification and management. However, most IoT applications primarily rely on wired power or batteries, leading to challenges such as main-tenance difficulties and limited operational lifes-pans after deployment. To address these issues, Ambient IoT has emerged as a highly anticipat-ed emerging technology. Ambient IoT devices operate without a dedicated power source or built-in battery, instead, they harvest energy from their surrounding environments to function. As wireless networks rapidly expand, the demand for spectrum resources has outpaced availability, creating an urgent need to improve spectrum utilization. This article explores key technologies essential for advancing spectrum sharing in Ambient IoT. Specifically, we provide detailed insights to new multiple access (MA) technol-ogies, cognitive radio (CR), symbiotic radio (SR) and full-duplex (FD), focusing on their fun-damental principles and associated challenges. Additionally, it outlines future research directions and challenges that spectrum sharing in Ambient IoT networks will face.