Physical Layer Design for Ambient IoT

There is a growing demand for ultra low power and ultra low complexity devices for applications requiring maintenance-free and battery-less operation. One way to serve such applications is through backscatter devices, which communicate using energy harvested from ambient sources such as radio waves transmitted by a reader. Traditional backscatter devices, such as Radio Frequency Identification (RFID), are limited by range, interference, low connection density, and security issues. To address these problems, the Third Generation Partnership Project (3GPP) is working on Ambient Internet of Things (AIoT) with a focus on standardizing various aspects ranging from physical layer design, to the protocol stack, to the device architecture. In this paper, we provide an overview of the standardization efforts on the physical layer design including physical channels and signals for A-IoT devices. We propose an adaptive thresholding based detection method for the receiver on both the device and reader, to improve the link performance. The improvement due to this method is shown using link level simulations of various configurations of reader-to-device and device-to-reader channels.