  The current development of 5G networks represents a breakthrough in the
design of communication networks, for its ability to provide a single platform
enabling a variety of different services, from enhanced mobile broadband
communications, automated driving, Internet-of-Things, with its huge number of
connected devices, etc. Nevertheless, looking at the current development of
technologies and new services, it is already possible to envision the need to
move beyond 5G with a new architecture incorporating new services and
technologies. The goal of this paper is to motivate the need to move to a sixth
generation (6G) of mobile communication networks, starting from a gap analysis
of 5G, and predicting a new synthesis of near future services, like hologram
interfaces, ambient sensing intelligence, a pervasive introduction of
artificial intelligence and the incorporation of technologies, like TeraHertz
(THz) or Visible Light Communications (VLC), 3-dimensional coverage.
