An OpenAirInterface-Based Ambient Backscatter Communication System Using Pilots

Ambient backscatter communication (AmBC) technology and zero-energy device (ZED) have been introduced as promising enablers for Internet-of- Things (IoT) applications in next-generation networks. AmBC is an eco-friendly technology that allows devices to communicate by backscattering ambient radio frequency (RF) waves, rather than generating signals by themselves. When introducing AmBC to cellular networks, ZEDs are proposed as self-powered backscatter devices connected to the 6G network. A ZED harvests energy solely from ambient and solar sources. Owing to its low power consumption and simple hardware design, ZED is poised to play a significant role in large-scale IoT applications, such as logistics and automated warehousing. In this paper, we develop an OpenAirInterface(OAI)-based AmBC platform and implement AmBC in a bistatic way, utilizing an OAI long-term evolution (LTE) base station(BS), an OAI LTE user equipment (UE) and a ZED. The ZED backscatters ambient RF waves from the BS and the UE decodes the backscattered data using pilots. This demonstrates the feasibility for a standard-compliant UE to function as an AmBC reader when the BS serves as an ambient source. Additionally, we propose a multi-frequency detector to enhance the detection performance of ZEDs. Finally, our work reveals the potential for new IoT use cases within existing architectures and for future technologies.