It’s possible that both are true depending on the definition of “calls”. It may be different with postmarketOS, but at least with LineageOS, there are phones where calls are supported over 3G but not VoLTE. So, while the phone and OS are technically capable of making calls, without VoLTE support they can’t actually do it because mobile providers have decommissioned their 3G networks.
Ah, USA problems. I don’t think anywhere else has decommissioned 3G just yet, though some plan to next year or so; https://en.wikipedia.org/wiki/3G#Decline_and_decommissions suggests the EU may even be planning to keep 2G alive as a fallback, which is an interesting decision.
I have used at least three phones (two Android, one PinePhone on Arch) that allegedly support VoLTE, but I have never had a phone call do anything other than drop to 3G on the Optus network in Australia (through at least three different carriers). I’m not sure quite what’s up with that, but I vaguely recall some kind of insanity about VoLTE not having any baseline codecs and carriers being able to operate a device whitelist and idiotic user-hostile things like that. I’m fuzzy on details, and have never tried asking the telco why it doesn’t work. I really dislike how opaque everything is in mobile telephony.
Keeping 2G+4/5G alive looks like a good option to me - 2G is supported by any GSM phone and has long range, 4/5G - high bandwidth for modern phones. I would not miss 3G at all if 2G and 4G will be available, but 2G decommission will turn a lot of working dump/feature phones into e-waste (I myself use multiple SIM-cards and some of them are in 2G-only phones).
2G isn't as spectrally efficient as 5G. It can't service nearly as many users in a cell so it ends up just being wasteful. Carriers do not want to waste their spectrum licenses on 2G service for some small minority of customers.
Those old feature phones are generating e-waste already as they're on their nth battery and have chargers with connectors not used by any other device.
Meh. For low bandwidth internet applications nothing in 2G is really a problem. Everything on the internet uses strong crypto for authentication these days. It would be nice to not have to replace cellular equipment every few years and have some compatibility.
The air interface for 2G is less secure than 5G. This means everything from signaling to actual payload is less secure. In terms of bandwidth, 5G is far more spectrally efficient than 2G. A low bandwidth 5G device can have far better battery life because it's communication duty cycle is much shorter.
A 2G service can't overlap with other services. So if you've got 2G service that's spectrum you can't use for anything else. It's also expensive to run since it essentially doubles the infrastructure needed to provide the service.
Excellent point. Spectrum for 2G is just the start. There's also several layers of backend services needed to keep 2G working and interoperable with modern voice networks. AIUI GSM's encryption is also relatively easy to break today. So 2G service is not only wasteful but a gigantic security hole.
Here in Japan, A career only supports VoLTE because it stopped CDMA2000 3G network for obvious reason. An other career don't support 3G WCDMA network on 5G plans because it's inefficient and LTE coverage is good enough. An other career only have 4G/5G network because it started recently. 2G network is completely gone a decade ago because no one use GSM.
