Non-orthogonal multiple access (NOMA) and caching are prominent technologies to support massive content delivery in wireless networks. By the advantage of superior data storage capability of the vehicles, a novel cache-aided NOMA paradigms has been introduced to vehicular networks for multimedia services, in which the cache utility and NOMA efficiency are both improved. However, the high mobility of vehicles causes a fast variation of channel state, which brings challenges in utilizing NOMA technology to guarantee the reliability of communication. In this context, we explore the optimization of power allocation and successive interference cancellation (SIC) ordering. Specially, we investigate the optimal Power Allocation and SIC ordering Selection (PASS) with imperfect channel estimation. To improve the quality of service and guarantee user fairness, we try to maximize the minimum achieved average outage data rate for all the vehicles under service. The PASS problem is non-convex because of the power and outage probability constraints. By Markov inequality, the probability constraint problem is firstly transformed into the non-probability problem for simplicity. Although the transformed problem is still non-convex, it is shown that the power allocation problem is quasi-concave when given the SIC ordering. Hence, we first solve the power allocation problem by the bisection method. Then, a greedy-meta schedule algorithm is proposed to determine the SIC ordering with low complexity. Numerical results show our proposed cache-aided scheme achieves a significant performance improvement.

非正交多路访问 (NOMA) 和缓存是支持无线网络中大量内容交付的重要技术。利用车辆卓越的数据存储能力，一种新颖的缓存辅助 NOMA 范式被引入用于多媒体服务的车载网络，其中缓存效用和 NOMA 效率都得到了提高。然而，车辆的高移动性导致信道状态的快速变化，这给利用 NOMA 技术保证通信可靠性带来了挑战。在此背景下，我们探索了功率分配和连续干扰消除 (SIC) 排序的优化。特别地，我们研究了最优功率分配和S IC 排序S信道估计不完善的选举（PASS）。为了提高服务质量并保证用户公平性，我们尝试最大化所有服务车辆的最低平均中断数据率。由于电源和断电概率的限制，PASS 问题是非凸的。通过马尔可夫不等式，为简单起见，首先将概率约束问题转化为非概率问题。尽管转换后的问题仍然是非凸的，但表明当给定 SIC 排序时，功率分配问题是准凹的。因此，我们首先通过二分法解决功率分配问题。然后，提出了一种贪心元调度算法来确定具有低复杂度的SIC排序。数值结果表明，我们提出的缓存辅助方案实现了显着的性能提升。