Altogether, it appears that doubling the current
cellular bandwidth is the best case scenario
at microwave frequencies. Alternatively, there is
an enormous amount of spectrum at mmWave
frequencies ranging from 3 to 300 GHz. Many
bands therein seem promising, including most
immediately the local multipoint distribution service
at 28–30 GHz, the license-free band at 60
GHz, and the E-band at 71–76 GHz, 81–86 GHz,
and 92–95 GHz. Foreseeably, several tens of
gigahertz could become available for 5G, offering
well over an order of magnitude increase over
what is available at present. Needless to say,
work needs to be done on spectrum policy to
render these bands available for mobile cellular.