C-V2X (Cellular Vehicle-to-Everything) technology was first proposed by 3GPP in the 4G (LTE) era with Release 14, and has evolved with each subsequent version, now capable of supporting modern transportation needs.Intelligent Transportation Systems (ITS), in addition to communication, involve numerous manufacturers, vehicles, and municipal aspects, and while its development has been slower, significant progress has been made, and there are high expectations for C-V2X. All of this is based on the following aspects:
I. C-V2X technology can improve road safety, traffic efficiency, and road information distribution efficiency. Compared to traditional in-vehicle sensors, it is relatively low-cost and highly effective. 3GPP actively promotes the standardization of LTE-V2X and NR-V2X, which has encouraged many organizations to develop C-V2X technology. However, the deployment of PC5-based C-V2X still faces some challenges.
II. C-V2X is an ecosystem that requires the active participation of industry stakeholders, including road traffic management departments, autonomous driving developers, network operators, and governments. To improve the level of C-V2X, governments need to promote the construction of road traffic facilities and unify relevant standards. For example, traffic light control systems need to be upgraded from traditional equipment to equipment with stronger processing capabilities. To transmit traffic information in a timely manner, the traffic light control system needs to send signal change information at a preset frequency of at least 10Hz. However, existing equipment in Taiwan cannot meet this requirement, necessitating an intermediate conversion process. However, the disadvantage of this process is that it increases message transmission delay. Therefore, there is a delay between the traffic light control console and the traffic lights, which violates Intelligent Transportation System (ITS) standards. This problem makes it difficult for C-V2X devices to obtain correct timing information for synchronization in SPAT applications. To address these issues, the government must establish unified standards to promote the upgrading of traffic light control systems.
III. Standardization of C-V2X technology application layer specifications. Some organizations follow European standards, some adopt American standards, and others combine both to develop national standards. It is currently unclear which standard will be adopted globally. Unifying standards and weighing the advantages and disadvantages of various standards should be part of the government's smart city agenda.
IV. 5G Sidelink Technology Applications: While C-V2X services have been tested and trialed in many regions, full 5G coverage still requires time. Initial applications will primarily focus on those with less demanding KPI (Key Performance Indicator) requirements. Once 5G achieves full coverage and Sidelink technology is fully implemented, C-V2X will reach a new level, where bandwidth, low latency, and high throughput will become key elements in its application scenarios; 5G NR-V2X deployment will lead to a comprehensive integration of the entire ecosystem.
V. Synchronized Development of Vehicles and Roadside Infrastructure: According to the international standard SAE J3016, autonomous driving is defined in levels 0-5; C-V2X services, in addition to the vehicles themselves, also place high demands on roads and related infrastructure; furthermore, a large amount of private and confidential information from IP cameras will be transmitted in public spaces, making information security protection a critical issue in PC5-based C-V2X deployment; countries need to develop relevant standards to define security policies; regulations and insurance claim mechanisms for road traffic accidents in intelligent transportation systems (ITS) are also under development.
