AmBC-Assisted Mobility Vehicle System With Partial NOMA Transmission

Abstract

This paper proposes the performance of a novel ambient-backscatter communication (AmBC)-assisted mobility vehicle system with partial non-orthogonal multiple access (NOMA) systems, where a jointly composite signal of NOMA and orthogonal multiple access (OMA) transmission is investigated to enhance the performance of the vehicle with high mobility and weak channel conditions in light of imperfect channel state information (CSI) and imperfect successive interference cancellation (SIC). Following that, we first derive exact closed-form expressions for the outage probability (OP) and ergodic capacity (EC) of vehicles and then conduct an asymptotic analysis in case of high signal-to-noise (SNR), gaining value information related to diversity order, modulation and coding gains, and ergodic slope. Through these mathematical frameworks, we clarify trade-offs in channel estimation procedure and vehicle performance, the advantages of partial NOMA in speeding up transmission rate operation area of weak vehicles compared to conventional NOMA, and the impact of imperfect SIC on the system outage performance. Monte-Carlo simulation examples validate the theoretical frameworks, along with several performance comparisons of the proposed partial NOMA and conventional NOMA. Moreover, it also shows that increasing the exploited portion bandwidth coefficient for individually serving vehicles with a weak channel condition enhances the operating target significantly without an outage event. Furthermore, exploiting partial NOMA for vehicles with a weak channel condition can save the transmit SNR of over 5 dB compared to using conventional NOMA while ensuring the performance of the rest vehicle.