In this paper, we investigate the performance of ambient backscatter communication non-orthogonal multiple access (AmBC-NOMA)-assisted short packet communication for high-mobility vehicle-to-everything transmissions. In the proposed system, a roadside unit (RSU) transmits a superimposed signal to a typical NOMA user pair. Simultaneously, the backscatter device (BD) transmits its own signal towards the user pair by reflecting and modulating the RSU's superimposed signals. Due to vehicles' mobility, we consider realistic assumptions of time-selective fading and channel estimation errors. Theoretical expressions for the average block error rates (BLERs) of both users are derived. Furthermore, analysis and insights on transmit signal-to-noise ratio, vehicles' mobility, imperfect channel estimation, the reflection efficiency at the BD, and blocklength are provided. Numerical results validate the theoretical findings and reveal that the AmBC-NOMA system outperforms its orthogonal multiple access counterpart in terms of BLER performance.

翻译：本文研究了基于环境反向散射通信非正交多址（AmBC-NOMA）的短包通信在高移动性车联网传输中的性能。在所提出的系统中，路侧单元（RSU）向一个典型的NOMA用户对发送叠加信号。同时，反向散射设备（BD）通过反射和调制RSU的叠加信号，向该用户对传输自身信号。考虑到车辆的高移动性，我们采用了时变衰落和信道估计误差的现实假设。推导了两位用户平均块错误率（BLER）的理论表达式。此外，对发射信噪比、车辆移动性、非理想信道估计、BD反射效率以及块长度进行了分析与讨论。数值结果验证了理论分析，并表明AmBC-NOMA系统在BLER性能方面优于其正交多址方案。