For VoLTE to truly deliver on that promise, engineers must prove that it's at least as good as, and preferably better than, other voice technologies.
Maybe not. As voice traffic becomes a smaller and smaller slice of bandwidth for service providers, it will make sense for the cellcos to combine their services over a common RF medium. And with VoIP now widely available over cabled networks, I just don't see why VoLTE should be such a huge leap - technically or "of faith."
I have been wondering just how long the cellcos will retain W-CDMA 3G after they start rolling out LTE. If this spectrum shortage is something real, as opposed to politically motivated make-believe, then I have to believe that the cellcos will do all they can to make the best use of the spectrum they already have allotted to them. Retaining separate 2G (original GSM TDMA), 3G, and LTE service is not the best use of spectrum. (GSM 2G is to be discontinued in 2016, so it seems the cellcos are not missing this point.)
I don't think it's a question of whether or not VoLTE gives a more perfect voice telephone experience than previous standards, in other words. That's probably down the list of what really matters here.
For VoLTE to truly deliver on that promise, engineers must prove that it's at least as good as, and preferably better than, other voice technologies. That's the challenge facing wireless carriers as they roll out VoLTE. Third-party test labs such as Intertek offer VoLTE testing services to carriers, handset manufacturers, and chipset manufacturers.