daveoc64
a year ago
This has been handled differently in the UK from a regulatory point of view from an earlier time in the rollout of 4G/5G networks, so things seem to have worked out better.
In the UK, carriers are only allowed to provide coverage in any given area to a phone if it is able to make an emergency call (999/112) in that area.
i.e. if the phone says you have a signal, you must be able to make an emergency call.
So, for a phone to actually show you as being connected to the network:
a) There must be 2G/3G coverage available for a CSFB call to take place.
or
b) The phone must support VoLTE (including for emergency calls).
Newer LTE (and 5G) spectrum deployments, like Band 20 LTE (800MHz), are being used to provide coverage in rural areas - even in places where there is no 2G/3G coverage, therefore these newer bands are often only made available to devices that support VoLTE.
If you have an old phone, that doesn't support VoLTE (including for emergency calls), then it will only connect to 4G networks in areas where there is still an overlapping 2G/3G layer.
This approach means that the carriers have had an incentive to make all devices support VoLTE with emergency calling. It has also been possible for the carriers to promote the 800MHz coverage as only being available on newer phones with VoLTE.
Thus much of the problems that Australia is having have been avoided.
Also:
Data-only devices aren't included in this requirement, as they can't/don't make emergency calls.
Roaming devices aren't affected (as far as I know).
UK carriers support VoLTE roaming in the USA, given the lack of 2G/3G networks for CSFB.
kalleboo
a year ago
> If you have an old phone, that doesn't support VoLTE (including for emergency calls), then it will only connect to 4G networks in areas where there is still an overlapping 2G/3G layer.
I guess the question is, how do they determine if a phone doesn't support VoLTE for emergency calls? That seems to be the problem in Australia, that there is no reliable way to detect it, so they're just using crude whitelists.
michaelt
a year ago
Surely for a phone to receive calls, the provider has to know whether it supports VoLTE? How else would the carrier know how to connect the call?
daveoc64
a year ago
The phone would have to actively make an IMS connection to use VoLTE, so the network would know when the device connects.
kalleboo
a year ago
The problem is there are phones that can make and receive normal VoLTE calls, but when and only when you make an emergency call, it drops down to 3G, since it doesn't know how to signal emergency QoS on the network for VoLTE calls.
There are no incoming emergency calls.
daveoc64
a year ago
I am not sure how they determine it, but I haven't ever seen the same level of problems reported with device support.
I can't say I've ever heard of a device in the UK supporting VoLTE for regular calls, but not supporting it for emergency calls.
emmelaich
a year ago
There are instructions on the Optus website to enable VolTE for my phone (Android Pixel).
The instructions make no sense; they refer to settings which do not exist. At least as described.
noncoml
a year ago
Maybe I’m dumb but didn’t understand how what you said about 112 calls helps incentivize carriers
daveoc64
a year ago
Band 20 LTE/800MHz allows the carriers to vastly increase their coverage area for a lot less money.
Customers can only access that spectrum if they have a VoLTE compatible (including emergency call) device.
The carriers have legally binding landmass and population coverage goals as part of the spectrum licensing terms.
The carriers can also market the fact that better rural coverage is available on newer devices.
Therefore the carriers have only been selling fully VoLTE compatible devices for many years and pushing as many VoLTE-enabling software updates out as possible.
dingaling
a year ago
> Therefore the carriers have only been selling fully VoLTE compatible devices for many years
However 35% of UKians bring their own phone under SIM-only contracts.
When my UK carrier ( Hutchinson 3 ) was switching off 3G I had weekly scare-emails stating that my phone would no longer work. Of course it did support VoLTE and works fine, but in the background they were using a whitelist.
wkat4242
a year ago
How did that end? Did they block you?
I have nothing but bad experience with these idiots anyway. Their support were real script monkeys. They were the worst provider in Ireland.
user
a year ago
usr1106
a year ago
I would never trust VoLTE. It's a complicated beast full of compatibility issues. My phone supports VoLTE but on a recent trip through Europe it fell back to 2G for most calls.
Edit: Those were ordinary calls. For emergency calls I have zero experience. The last time I made one I had other things in mind then checking my network monitor app.
bestham
a year ago
Due to the VoLTE end-ro-end encryption from your phone (UE) to the home operator, some countries (at least Sweden) will force downgrade inroaming users to circuit switched voice (2G/3G) in order to do lawful intercept (LI).
franga2000
a year ago
Is this done for everyone or just people under wiretap orders? I don't see why the network wouldn't be able to downgrade selectively since phones automatically fail over and the VoLTE service could simply refuse to authenticate or whatever.
wkat4242
a year ago
What will they do once 2G/3G gets decommissioned? Stop allowing roaming?
usr1106
a year ago
It's still several years. I guess they just hope many phones of today won't be in use anymore and newer ones will have better compatibility. In practice some phones won't just work anymore, like in the original article.
richardwhiuk
a year ago
VoLTE is not end to end encrypted.
patrakov
a year ago
Here is my experience in the Philippines:
In 2022, I imported a Samsung Galaxy A02 phone from Turkey, which I bought there in a retail store. It works, but could use VoLTE with Globe or SMART, and the operators' personnel provide conflicting answers as to why. Finally, they revealed the existence of a whitelist of models. But it worked with DITO, which is a 4G-only operator, but even that is not an argument for Globe and SMART to extend their whitelist.
Same for the newer POCO X4 Pro (international version) which I bought online.