This little gem of information from one our our local service providers.
Over the past two years, mobile network operators (MNOs) have been working with manufacturers to enable VoLTE on as many mobile devices as possible, including existing models. For each MNO, this process involves working with manufacturers of each type of device to test VoLTE on their network before it can be enabled for the customer.
It probably explains why some of us may have issues. I wonder what makes some networks so special that they need to “approve” what models are connected to their network. Let’s face it, they can only buy their network from a small handful of suppliers who in turn supply to operators the world over. I somehow doubt the network equipment suppliers are custom building their equipment, so why are the network operators so precious?
The reason is: VoLTE is still in the beta stage and only the base set of functionality is implemented. Don’t expect other features to be already implemented, when a long awaited feature comes out as a beta version on a single device.
It’s been over a year since I researcher the state of VoLTE, but to the best of my knowledge, you are correct. The problem seems to be that while how VoLTE works is well defined, how to actually implement it is not. Do carriers take the iPhone route and make users download an app (for those whose phones don’t have it built in), do you push software to the phone, do you utilize the SIM in some way, etc.? Everybody does it differently, if at all. IMHO this is where governments need to step in and tell their carriers that no changes will be made to their 2G, 3G, 4G, or 5G networks until they can prove interoperability with each other on a national level, and then with the outside world. Sadly AFAIK no country with a strong track record on consumer rights has gotten this ball rolling. I tried making some noise here in the US over a year ago, but no one seemed to be listening
The first VoLTE phone was sold in 2012, and while I do expect interoperability testing was important during those early years, by now I would be surprised if all parties didn’t know how it works. The carriers know how major phone manufacturers implement VoLTE, and the phone manufacturers know how the carriers’ networks operate. The pessimist (honestly, the realist) in me says that some networks are precious because they make more $$$ that way. Either by selling customers new phones that have already been approved, or by charging the phone maker an exorbitant fee for compatibility testing. Here in the US, T-Mobile ran such a program for years. They still might. Back in 2018 when my XA2 was new, Sony apparent balked at the testing fee, and not wanting to upset T-Mobile, sold the phone with VoLTE disabled. But VoLTE was still sort of theoretical then, because the 2G and 3G networks were still robust. Now the chickens have come home to roost because with these networks waning to make way for 5G, you could be left with a phone that, due only to greed, may no longer be able to make calls. (Correct me if I’m wrong…towers can put out only so much signal, so that new 5G signal has to eat into something, a zero sum game.) And it makes me sick.
Caveat emptor: I am not a wireless engineer and have never worked for a wireless carrier or phone manufacturer. I can dig up links describing what is known of T-Mobile’s VoLTE compatibility testing program if anybody doubts me.
T-Mobile and band 12 support in unlocked smartphones put in the spotlight
T-Mobile: All Band 12 LTE devices on our network must support VoLTE, E911
These are years old, but should still make good reading. In this context, the “band 12” issue is inconsequential, but note the article comments including those from the author. The person who collected the links speculates that T-Mobile’s certification program is no more.
Keep in mind that of the three national US carriers, T-Mobile is/was the most generous. At the time, AT&T operated a strict white list, the approved VoLTE phones consisting of no more than a few dozen phones, most of which they sold themselves. Verizon also used a white list, which wasn’t much better. Again, much of this could have changed. Sadly I don’t have time anymore to keep up the research and advocacy.
A change is that my Blackview is no longer getting VoLTE on 2degrees. VoWiFi is still working though. Unfortunately neither works on the 10 III.
Tested Vodaphone today. Neither VoLTE or VoWiFi.
My mates Blackview does VoLTE on voda, but not VoWiFi.
If I could find anyone to ask, I would ask if they can provision them. It’s looking more like a whitelisting issue to me.
It would be useful to find out what which country the phone was intended to be sold in, Android software version was installed and what network operator the phone had been used on prior to flashing Sailfish.
Sony have this note on their specs regarding the installed bands. "Availability may vary depending on country, carrier, software version and user environment."
Slightly OT, but out of curiosity, is there any change to get an official statement regarding upcoming or planned VoWiFi support, and X10ii support?
Thank you.
I’m not aware that there’s been any announcement about VoWiFi support. You could ask about it at the community meeting, which is usually a good way to get specific answers to specific questions like this. However, since VoLTE is still beta functionality, I wouldn’t expect anything too concrete as an answer at this stage.
Do some people have collected experience with VoLTE mobility? Do thinks like call handover or fallback to 2G work reliable? Did people experience smooth calls when driving around with VoLTE enabled and so on?
I had some issues connecting to VoLTE. In the end I removed the SIM card and plugged it back in and after 4h of failing to register it worked immediately. I did try rebooting and other things before it. So if anyone has issues connecting, try removing the SIM tray for a few seconds.
