  Ultimate goal of next generation Vehicle-to-everything (V2X) communication
systems is enabling accident-free cooperative automated driving that uses the
available roadway efficiently. To achieve this goal, the communication system
will need to enable a diverse set of use cases, each with a specific set of
requirements. We discuss the main use case categories, analyze their
requirements, and compare them against the capabilities of currently available
communication technologies. Based on the analysis, we identify a gap and point
out towards possible system design for 5G V2X that could close the gap.
Furthermore, we discuss an architecture of the 5G V2X radio access network that
incorporates diverse communication technologies, including current and cellular
systems in centimeter wave and millimeter wave, IEEE 802.11p and vehicular
visible light communications. Finally, we discuss the role of future 5G V2X
systems in enabling more efficient vehicular transportation: from improved
traffic flow through reduced inter-vehicle spacing on highways and coordinated
intersections in cities (the cheapest way to increasing the road capacity), to
automated smart parking (no more visits to the parking!), ultimately enabling
seamless end-to-end personal mobility.
