If past experience is any indication, by 2050 5G should be a thing of the past, possibly with a few vestige of it still ticking in a few places.
Wireless systems have shown a constant pattern of taking about 10 years from the time they are first being discussed to the time they are actually becoming widespread and have lasted about 30 years in operation.
We have started talking about 5G at the beginning of this decade and in the next decade we should see its deployment. Thirty years down the lane of time it should be fading away.
However, 5G, as I mentioned a number of times in these posts, is not 4+1 G, hence it may turn out to have a different life span.
5G is about vertical roaming. Previous systems, analogue, digital (2G), 3G and 4G focused on horizontal roaming, that is ensuring that a device moving out of the coverage of one cell could remain connected by using a nearby cell with communication handed over from one cell to the next. This clearly posed the problem of coverage, if a cell was not flanked by another cell at its border a device “walking out” of its area would lose connectivity. That’s why Telcos are proudly advertising the coverage of their networks.
4G doesn’t provide a coverage as good as 3G, which in its first years of service did not provide a coverage as good as 2G. That was not a big issue since if you happened to be in an area where 3G was not available your phone would switch to 2G and you were able to make a call (it works the other way around but it seldom applies since 2G coverage is usually much broader than 3G). However, if you start a 3G call and move to an area with WiFi coverage there is no handover, your device remains on 3G. Your device (and the network) did not have the capability to jump from one system to a different one. Only horizontal roaming is supported.
As time goes by more and more access opportunities become available: cell networks overlaying one another, pico cells, wifi hot spots and so on.
With 5G the idea is that your device can make use of any system, within the same call. If the device walks away from a given system/spectrum coverage and you have a 5G terminal the device itself will make use of a different system (like wifi) and a different spectrum.
It is even better! Within the same call (same session in ISO parlance) the device is able to use more than one system and spectrum at the same time, like sending part of the data on a wireless system and part on a different one. The device becomes the “master” of the spectrum and can potentially use whatever spectrum is available.
In a way, this is as good as it gets.
Yes, in the future we are going to have more spectrum bands available (and 5G sometimes is associated to the possibility of using higher frequencies), we will have more powerful chips in the device that will be able to manage them (at the same time, in parallel), but basically we will see more and more of 5G.
Of course marketing will make sure that we will be offered 5G+ and then 6G and so on. But, technically speaking, 5G will rule in the future for what spectrum access is concerned.
Mind you. This does not mean that we wont see any more evolution. More and more sophistication can be expected in the usage and management of the spectrum, with semantics taking the upper hand over syntax (it is like saying that the way you communicate, at technical and architectural level will depend on “what” you communicate).
With 4G we have reached the end of the line in terms of spectrum efficiency, with 5G we are reaching system wide spectrum efficiency.
Hence, 5G will outlive, this is my bet, the 30 years life span that has basically framed the previous systems.