Vehicular communications for autonomous and intelligent transportation systems: a comprehensive survey

The rapid advancement of Autonomous and Intelligent Transportation Systems (A-ITS) has driven the widespread adoption of vehicular communication technologies to enhance the safety, efficiency, and sustainability of modern transportation networks. Key communication technologies, including Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), and Vehicle-to-Everything (V2X), are fundamental for the operation of A-ITS, enabling seamless interaction among vehicles, infrastructure, and other road users. This survey provides a comprehensive analysis of these critical communication technologies and explores the integration of edge computing and Artificial Intelligence (AI) to optimize A-ITS performance. Furthermore, we identify and discuss the major challenges facing A-ITS, including network reliability, data privacy, security, and interoperability, which must be addressed for successful deployment. We also examine the role of emerging 5G/6G networks in smart cities and the Internet of Things (IoT), focusing on their potential to advance autonomous transportation systems. This work serves as a valuable resource for understanding the current state and future prospects of vehicular communications in A-ITS.