  The global 6G vision has taken its shape after years of international
research and development efforts. This work culminated in ITU-R's
Recommendation on "IMT-2030 Framework". While the definition phase of
technological requirements is currently ongoing, 3GPP's standardization process
on 6G networks is expected to start in 2025 and worldwide commercialization
around 2030. This article serves as a comprehensive guide to 6G by providing an
overall vision, a contemporary survey of the main literature, and an
informative tutorial-type presentation style. In our vision, 6G will be based
on three fundamental elements: wireless, artificial intelligence (AI), and the
Internet of Everything (IoE). Consequently, 6G can ultimately become the
Intelligent Network of Everything while serving as an enabling platform for the
next major disruption in mobile communication, called mobile intelligence. The
potential of mobile intelligence is that anything can be made connected,
intelligent, and aware of its environment. This will revolutionize the way how
devices, systems, and applications are designed; how they operate and interact
with humans and each other; and how they can be used for the benefit of people,
society, and the world in general. After high-level visioning, the main details
of 6G are discussed, including fundamental elements, disruptive applications,
key use cases, main performance requirements, potential technologies, and
defining features. A special focus is given to a comprehensive set of potential
6G technologies, each of which is introduced in a tutorial manner. Finally, we
speculate on what comes after 6G and sketch the first high-level vision of 7G.
All in all, the objective of this article is to provide a thorough guide to 6G
in order to serve as a source of knowledge and inspiration for further research
and development work in academia, industry, and standardization bodies.
