Energy Efficiency Optimization for Backscatter Enhanced NOMA Cooperative V2X Communications Under Imperfect CSI

Automotive-Industry 5.0 will use beyond fifth-generation (B5G) technologies to provide robust, computationally intelligent, and energy-efficient data sharing among various onboard sensors, vehicles, other devices. Recently, ambient backscatter communications (AmBC) have gained significant interest in the research community for providing battery-free communications. AmBC can modulate useful reflect it towards near devices using energy frequency of existing RF signals. However, obtaining channel state information (CSI) systems would be very challenging due no pilot sequences limited power. As one latest members multiple access technology, non-orthogonal (NOMA) has emerged as a promising solution connecting large-scale over same spectral resources B5G wireless networks. Under imperfect CSI, this paper provides new optimization framework transmission enhanced NOMA cooperative vehicle-to-everything (V2X) We simultaneously minimize total transmit power V2X network by optimizing allocation at BS reflection coefficient sensors while guaranteeing individual quality services. The problem minimization is formulated non-convex coupled on variables, making complex challenging. Therefore, we first decouple original into two sub-problems convert nonlinear rate constraints linear constraints. Then, adopt iterative sub-gradient method obtain an efficient solution. For comparison, also present conventional without AmBC. Simulation results show benefits our proposed terms achievable efficiency.