Multi-Technology Integration in Hybrid V2X Networks: A Survey, Challenges, and Open Issues

The rapid advancement of autonomous and connected vehicles has driven the development of sophisticated vehicular communication networks that integrate several communication technologies, such as 802.11p, 4G/LTE, 5G, and soon 6G technologies. These hybrid V2X networks represent a key element for the future of smart mobility and connected cities, promising more improved safety, efficiency and comfort. However, due to their heterogeneous nature, integrating these different technologies together also poses several significant challenges and issues that require advanced solutions to take full advantage of them. This survey provides an in-depth review of latest research on solutions addressing various challenges in hybrid V2X communication systems. Firstly, we provide an overview of V2X communication and examine the different standards and emerging technologies that structure and enable these networks. Next, we discuss the top issues facing the practical implementation of hybrid V2X systems, as well as the latest proposed solutions that have been developed to counter these challenges. We offer in addition a qualitative evaluation of these identified approaches to highlight current research limitations. Finally, we highlight key open research issues, which require innovative approaches to fill the gaps in current approaches and ensure reliable communication for future applications of V2X technology.