On Outage Performance of Backscatter NOMA System Under Imperfect DLI Cancellation

Backscatter communication and non-orthogonal multiple access (NOMA) represent emerging paradigms in wireless communication, offering promising solutions to boost spectral and energy efficiency for energy-constrained devices in 6G networks. This work introduces a tailored symbiotic radio system designed for Internet of Things (IoT) devices, proposing an innovative framework that integrates backscatter-based IoT devices into power-domain NOMA networks. In this system, the primary base station employs NOMA principles to serve both far and near users simultaneously, while IoT devices equipped with backscattering technology transmit their data over the primary signal. The IoT transmitter not only serves the IoT receiver but also enhances the performance of the far user. The paper thoroughly examines outage probabilities for both NOMA and IoT networks. It delves explicitly into the outage probabilities of IoT receivers, considering both perfect and imperfect direct link interference cancellation. The results demonstrate significant performance improvements over traditional orthogonal multiple-access methods. Furthermore, Monte Carlo simulations are employed to validate the accuracy of the theoretical analysis.