Ambient IoT in 3GPP Release 19: A Survey

The ambient Internet of Things (IoT) that utilizes harvest energy is gaining recognition as an innovative technology in the wireless communication industry. The devices associated with this technology, known as Ambient IoT devices, are characterized by being battery-less, low-cost, maintenance-free, smaller size, and low hardware complexity. Recently, the Third Generation Partnership Project (3GPP) has initiated a study on integrating Ambient IoT with the cellular network, to provide widespread and flexible connectivity, meeting the massive deployments of these class ultra-low power Ambient IoT devices. This paper outlines a timely survey of the Ambient IoT within 3GPP Radio Access Network (RAN) Release 19. It presents the technical foundations of Ambient IoT, encompassing representative use case, connectivity typology, service requirement, and device type. Furthermore, it delves into an analysis of the essential protocol functions and gives the signaling procedures for the Ambient IoT. In addition, the paper explores several potential considerations for Ambient IoT that might be explored in the future.