# Evolution of V2X Communication and Integration of Blockchain for Security Enhancements
## 1 Introduction  
Vehicles are important part of our daily commute; they have become a necessity rather than a luxury. Vehicle to Everything (V2X) communications provide driving safety, traffic efficiency, and road information in real-time in vehicular networks. The vertical automobile industry is undergoing major technical advances with a revolutionary goal in the development of intelligent and autonomous vehicles. The intelligent and autonomous vehicles may be classified as Automotive Vehicles and Connected Vehicles. The interconnection between vehicles is commonly known as Connected Vehicles in the United States [1] and Cooperative Intelligent Transport Systems (C-ITS) in EU countries [2]. The connected vehicle technology, or C-ITS, is based on VANETs for communicating safety and non-safety messages. Because of the ITS technological advancements, C-ITS has gained a lot of attention from industry and academiathat could potentially help traffic-flow situations (such as congestion, accidents, and road construction), ensure safe driving, and provide multimedia entertainment in vehicles. The advancement of connectivity in vehicles includes different types of communication technologies. In vehicular networks, the vehicle can communicate with neighbor vehicles, infrastructures, pedestrians, cyclists, etc. After the 3 GPP came into the existence with C-V2X technology, they closely focused on its development by launching a range of specification standards to improve the V2X technology further. At the start of the DSRC era, the 3G cellular infrastructure was also in operation; however, it was not able to satisfy the strict specifications needed for V2X communications. Furthermore, with the advancement of wireless technologies, 4G or LTE networks were launched with high speed, low latency, high throughput, and high reliability. LTE for vehicles (LTE-V) was introduced in 2016 as an alternative technology besides DSRC for vehicular networks to support intelligent transportation. However, LTE-V still cannot support ultra-low latency, ultra-high reliability and ultra-high bandwidth requirements for V2X applications, such as critical messages and coordinated platooning. Since then, New Radio (NR) technology has been introduced that enhances the C-V2X applications. Every release has been enhanced further almost every year. The goal of NR V2X is not to replace the already standardized C-V2X technology. The aim is to provide additional support for all V2X applications. In a region where new vehicles will have both C-V2X and NR V2X functionalities, C-V2X and NR V2X will likely coexist. Some of the notable key features of NR V2X are side link mode 2, improved scheduling mechanisms, different transmission mechanisms (like unicast, groupcast, and broadcast), various side link modes, PHY layer improvements, etc. The emerging 5G technology will further help C-V2X and, at the same time, increase security. In contrast to the existing cellular networks, 5G wireless networks will be decentralized and omnipresent, with particular focus on security and privacy requirements. The evolution of C-V2X towards 5G NR V2X provides adequate requirements and new possibilities for current and future intelligent and autonomous driving industries, while, at the same time, retaining backward compatibility. Meanwhile, edge computing has emerged as an expansion of cloud computing, and it is considered as enabling technology for driving 5G ecosystems forward. It delivers computing facilities at the edge of the network to nearby vehicles or other devices, allowing for even shorter communication delays in processing and storage. In vehicular networks, Multi-access Edge Computing (MEC) reduces delays and background congestion by computation offloading and distributed content caching. It provides a series of computing services such as edge data storage, task processing, real-time network access, and Quality of Service (QoS) improvements with ultra-low latency data transmissions.