The paradigm of Internet of Vehicles (IoV) as an extension to the Internet of Things (IoT) concept can assist the development of smart cities. IoV relies on vehicular communications to allow vehicles to communicate in real time with other vehicles, roadside infrastructure, and pedestrians. The main goal is to enable not only road safety services but also time-constrained IoT applications. In this context, Cellular Vehicle-to-Everything (C-V2X) communication is a prominent technology to accomplish IoV goals. Currently, there are two versions of C-V2X available, long-term evolution-V2X (LTE-V2X) and new radio-V2X (NR-V2X), and in both, mechanisms of resource allocation (RA) play an important role in their performance. Therefore, our goal in this article is to present an extensive state of the art of RA on C-V2X technology. Thus, we first present the main technical aspect related to LTE-V2X and NR-V2X technologies. Afterward, we present and categorize the related works for both technologies, pointing out their main differences, advantages, and drawbacks. Finally, we present the challenges, open issues, and future technical trends related to RA in C-V2X.

中文翻译：

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C-V2X中的资源分配模式：从LTE-V2X到5G-V2X


车联网（IoV）范式作为物联网（IoT）概念的延伸，可以助力智慧城市的发展。车联网依靠车辆通信来允许车辆与其他车辆、路边基础设施和行人进行实时通信。主要目标是不仅支持道路安全服务，还支持时间有限的物联网应用。在此背景下，蜂窝车对万物（C-V2X）通信是实现车联网目标的一项重要技术。目前，C-V2X有两个版本，长期演进V2X（LTE-V2X）和新无线电V2X（NR-V2X），在这两个版本中，资源分配（RA）机制都发挥着重要作用。他们的表现。因此，我们在本文中的目标是展示 C-V2X 技术上 RA 的广泛最新技术。因此，我们首先介绍与 LTE-V2X 和 NR-V2X 技术相关的主要技术方面。随后，我们对这两种技术的相关工作进行了介绍和分类，指出了它们的主要区别、优点和缺点。最后，我们提出了 C-V2X 中与 RA 相关的挑战、未决问题和未来技术趋势。