  Currently, autonomous vehicles are able to drive more naturally based on the
driving policies learned from millions of driving miles in real environments.
However, to further improve the automation level of vehicles is a challenging
task, especially in the case of multi-vehicle cooperation. In recent heated
discussions of 6G, millimeter-wave (mmWave) and terahertz (THz) bands are
deemed to play important roles in new radio communication architectures and
algorithms. To enable reliable autonomous driving in 6G, in this paper, we
envision collaborative autonomous driving, a new framework that jointly
controls driving topology and formulate vehicular networks in the mmWave/THz
bands. As a swarm intelligence system, the collaborative driving scheme goes
beyond existing autonomous driving patterns based on single-vehicle
intelligence in terms of safety and efficiency. With efficient data sharing,
the proposed framework is able to achieve cooperative sensing and load
balancing so that improve sensing efficiency with saved computational
resources. To deal with the new challenges in the collaborative driving
framework, we further illustrate two promising approaches for mmWave/THz-based
vehicle-to-vehicle (V2V) communications. Finally, we discuss several potential
open research problems for the proposed collaborative driving scheme.
