Gigabit Mobile Networks?

For practical reasons, each successive generation of mobile networks has used higher and different frequencies, at least at first.

The reasons are simple enough. The new network has to be built and then operated at the same time that the older network or networks remain in operation. 

Over time, the older frequencies are reclaimed, but the principle has been clear enough: each new network uses higher frequencies.

Also, as a rule, each new succeeding network has required bigger channels. Where analog networks used 30 kHz, 2G used up to 200 kHz. 3G networks used allocations up to 5 MHz, while 4G networks can use channels as big as 40 MHz (though typically paired 10 MHz or paired 20 MHz appears already to be most common). 

In some cases, it is possible to reuse existing spectrum, as regulators in the United Kingdom expect to be able to do by converting former TV spectrum to mobile applications in the 700-MHz bands.

In other markets, that option likewise could exist, but one issue could be the time and expense of "clearing" existing users from the spectrum. In some cases, where new spectrum is available, it might be reasonable to use that new spectrum, including spectrum mostly in the past considered most suitable for microwave backhaul. 

That of course has propagation and bandwidth implications. As a rule, the basic trade off is distance and bandwidth: lower frequencies propagate further, but higher frequencies can carry more information, for any given amount of spectrum. In other words, 10 MHz at 700 MHz travels much further than 10 MHz worth of signals at 2 GHz. 

That has engineers working on ways to compensate for propagation characteristics of much-higher frequencies expected to be used for future fifth generation 5G networks that will follow 4G in roughly a decade. 

Samsung says it now has an experimental system supporting 1 Gbps in the 28 GHz band using adaptive array transceiver technology with 64 antenna elements. Samsung believes 10 Gbps is feasible using the approach. 

In the past such frequencies were considered unsuitable for access applications, though more suitable for backhaul. In the United States, the LMDS service, originally conceived of as a way to provide fixed wireless "cable TV,"  occupies the following spectrum blocks:

27.5 – 28.35 GHz
29.1 – 29.25 GHz
31.075 – 31.225 GHz
31.0 – 31.075 GHz
31.225 – 31.3 GHz

Though there were failed attempts to re-purpose LMDS spectrum for communications use around the time of the Internet bubble, those efforts failed, partly for technology cost reasons and partly because of lack of demand. But technology gets better over time. So does cost. 

So the issue is whether higher frequencies, in addition to supporting mobile industry needs, might also be allocated for non-licensed users as well. If regulators really want more competition to the dominant ISPs, on a facilities-based basis, they will have to look at that.