  Ambient internet of things (IoT) is the network of devices which harvest
energy from ambient sources for powering their communication. After decades of
research on operation of these devices, Third Generation Partnership Project
(3GPP) has started discussing energy harvesting technology in cellular networks
to support massive deployment of IoT devices at low operational cost. This
article provides a timely update on 3GPP studies on ambient energy harvesting
devices including device types, use cases, key requirements, and related design
challenges. Supported by link budget analysis for backscattering energy
harvesting devices, which are a key component of this study, we provide insight
on system design and show how this technology will require a new system design
approach as compared to New Radio (NR) system design in 5G.
