Optimized Resource Allocation in NOMA-Enabled ISAC Systems With RFID Backscatterers

This paper investigates a non-orthogonal multiple access (NOMA)-enabled multi-user transmission system in a backscatter communication(BackCom) environment with integrated sensing and communication (ISAC). In this configuration, a base station (BS) simultaneously serves multiple users through a communication beam while utilizing a sensing beam to detect the presence of an radio frequency identification (RFID) tag. A joint beamforming design problem is formulated to maximize the sum-rate for the users while considering the constraints for successive interference cancellation (SIC) and the minimum quality of service (QoS) for all the communication users and the detection of the tag. Lagrangian dual transformation is used to address the non-convex nature of the objective function. Due to the coupling of variables, an alternating optimization (AO) based algorithm is proposed with guaranteed convergence. Through numerical simulations, we validate the efficacy of our proposed algorithm. Furthermore, we assess the impact of several key parameters on system performance, including the number of transmitting antennas at the BS, the available transmit power at the BS, the minimum QoS for the communication users, and the number of communication users.