Transmit Power Minimization for STAR-RIS aided Bistatic Backscatter Networks

Abstract

Bistatic backscattering communication (BackCom) allows passive tags to send signals over long distances, but requires proximity to the carrier emitter (CE). Otherwise, the system would suffer from severe path loss, which need to be compensated by a high transmitting power of the CE. This paper presents an inventive BackCom system that makes use of the Simultaneous Transmitting and Reflecting Reconfigurable Intelligent Surface (STAR-RIS), which could improve the deployment flexibility of BackCom devices at both sides of STAR-RIS simultaneously. With the ensurance of the BackCom performance, we focus on minimizing the CE transmitting power through optimizing STAR-RIS phase shift and power splitting coefficient of tags. Numerical results reveal that the CE transmitting power in bistatic BackCom systems can be greatly saved with the assistance of STAR-RIS.