  New research directions will lead to fundamental changes in the design of
future 5th generation (5G) cellular networks. This paper describes five
technologies that could lead to both architectural and component disruptive
design changes: device-centric architectures, millimeter Wave, Massive-MIMO,
smarter devices, and native support to machine-2-machine. The key ideas for
each technology are described, along with their potential impact on 5G and the
research challenges that remain.
