On the Performance of SIC-based NOMA in the C-V2X Sidelink Autonomous Mode

The next generation of connected and autonomous vehicles (CAVs) will rely on short-range cellular vehicle-to-everything (C-V2X) sidelink communication technology. However, existing radio resource allocation schemes for sidelink communications are susceptible to interference, which can limit data delivery performance. In this study we investigate the use of advanced receivers that employ successive interference cancellation (SIC) technology, meaning non-orthogonal multiple access (NOMA), under conditions that have not yet been considered. In particular, we focus on the sidelink of the latest 5G New Radio (NR)-V2X assuming both periodic and aperiodic broadcast traffic, exploiting either the legacy sensing-based semi-persistent scheduling (SB-SPS) or sensing-based dynamic scheduling (SB-DS), and discuss the possible use of blind retransmissions. Extensive simulations show that resolving the collisions by increasing the complexity of the receiver can be more beneficial than designing sophisticated allocation protocols that attempt to avoid them. Additionally, it is shown that a significant improvement is obtained also with non-ideal cancellation capability and limited cancellation iterations.