Now that all German network operators have switched-on VoLTE for voice services on LTE and are transitioning their subscribers to VoLTE step by step I can visualize a UMTS switch off in the mid-term quite well. Agreed, were aren’t quite there yet but the list of reasons to keep 3G running has become significantly smaller:
One major aspect will be how quickly VoLTE actually takes off and thus reduces the need to fall back to 3G during voice calls. For the moment, network operators seem to move their subscribers to VoLTE step by step, some slower, some faster. In other words, even though VoLTE is now up and running, not everyone automatically uses it.
Also, to be able to use VoLTE, one needs an LTE smartphone with an embedded VoLTE client. For the moment, only network operator device variants, at least in Germany and I suppose in the rest of Europe as well, come equipped with VoLTE capabilities. Buy the same device outside of an operator store and it won’t come with VoLTE. That will change in the future once the dust has settled a bit and device manufacturers, operating system and chipset vendors start treating VoLTE as a black box but I think that it is still some time away. Two to three years seems a realistic time frame for me until VoLTE comes out of the box in every new VoLTE device outside operator stores but that’s just gut feeling.
And once that is in place, network operators have to wait a while until the “installed based” of non-LTE and non-VoLTE devices has thinned out considerably. Telenor in Norway says it expects all of this to happen until 2020 by which they want to switch-off their 3G network. And in 2025 they want to ax their GSM network as well. The timing is a bit tight but if a network operator accepts that voice fallback of non-VoLTE devices will be to 2G without data capabilities during the call than they can certainly meet these deadlines.