NO-V2X: Non-orthogonal Multiple Access with Side Information for V2X Communications

We study a vehicle-to-everything (V2X) communication scenario where multiple vehicles coming from different road segments converge at a road junction and exchange their information via a road side unit. The high-mobility of vehicles determines that the communication is time-critical. If conventional orthogonal multiple access (OMA) is applied, not only the orthogonal resource allocation but also the scheduling overheads will incur significant delay. In addition, orthogonal domain may not be identified within short contact time among vehicles and the road-side unit. In contrast, non-orthogonal multiple access (NOMA) can provide low-delay and reliable communication by exploiting the overlapped or collided signals. In this paper, we investigate the application of NOMA with side information in V2X communications as the Non-orthogonal V2X (NO-V2X) scheme. NO-V2X takes the advantage of side information and physical-layer network coding (PNC) to increase the decoding success rate in the uplink phase and to reduce the required transmission power in the downlink phase. Our simulation results show that NO-V2X outperforms OMA and the conventional NOMA with successive interference cancellation (SIC).