STARRIS-Assisted IoV NOMA Networks with Hardware Impairments and Imperfect CSI

In this paper, we consider a simultaneously transmitting and reflecting reconfigurable intelligent surface (STARRIS)-assisted Internet of Vehicles non-orthogonal multiple access network. For practical considerations, the impacts of residual hardware impairments and imperfect channel state information are investigated. For such a setup with three different protocols, including time switching (TS), energy splitting, and mode switching (MS), we present the outage probability (OP) analysis for the network. Moreover, the probability of signal-to-noise ratio (SNR) gain and the delayed outage probability are further investigated. Compared with the traditional relaying scheme, the obtained results show that the STARRIS-assisted system achieves better delay performance. Furthermore, for the STARRIS-assisted system, the TS protocol achieves the best performance, while the MS protocol has the worst performance. In addition, considering the base station with multiple antennas, the expression for the OP is derived and error floors at high SNRs due to imperfect channel state information constraints exist. Finally, one can readily observe that increasing the number of STARRIS elements and antennas of the source can improve the outage performance.