  The standardization of fifth generation (5G) communications has been
completed, and the 5G network should be commercially launched in 2020. As a
result, the visioning and planning of sixth generation (6G) communications has
begun, with an aim to provide communication services for the future demands of
the 2030s. Here we provide a vision for 6G that could serve a research guide in
the post-5G era. We suggest that human-centric mobile communications will still
be the most important application of 6G and the 6G network should be human
centric. Thus, high security, secrecy, and privacy should be key features of 6G
and should be given particular attention by the wireless research community. To
support this vision, we provide a systematic framework in which potential
application scenarios of 6G are anticipated and subdivided. We subsequently
define key potential features of 6G and discuss the required communication
technologies. We also explore the issues beyond communication technologies that
could hamper research and deployment of 6G.
