Further, WiFI calling (at least with the carriers I use) allows one to place calls that roam from WiFi to cell to WiFI and these calls are to the PSTN and the person on the other end neither knows nor cares that I’m using WiFi calling . . . so definitely not Matrix.
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Since I have no cell signal from ANY carrier for about a mile radius right around my house I HAVE to have wifi calling ability. I have an AT&T femtocell now that works well when it’s up but it crashes fairly often anymore. So I’d really like to purchase a Librem 5 but won’t be able to unless it supports wifi calling.
As my current phone is dead I have to buy a new phone now. Do I buy a cheap one while I wait for a wifi calling enabled Librem 5 or do I buy a nice one since wifi calling won’t be supported on the Librem 5???
ANY help answering this question would be GREATLY appreicated!
Greg
I’m interested in this as well
I see that WiFi calling is also being called “VoWiFi”, to add to its existing profusion of names.
Skype would provide this if you pay for a Skype out number, etc. Not what the OP is after but a solution nonetheless.
yes, this needs carrier support, but there are a lot of carriers already supporting it: https://en.wikipedia.org/wiki/Generic_Access_Network#Service_deployments
In theory this could happen.
Voive-over-WiFi (VoWiFi) aka WiFi-Calling is an open standard and can be implemented as free software.
However, it is also a very complex standard that is very difficult to implement (as is VoLTE which is closely related and based on the same software stack).
I don’t see a free IMS/VoLTE/VoWiFi-stack for phones coming any time soon; if the Librem gets VoLTE, it will be a proprietary implementation in the blackbox modem, which right now is the only reasonable way to do it - since the WiFi-module is separated, it will not be possible to include this.
Additionally there is the issue of carrier certification: mobile network carriers have stringent quality requirements, and they tend to whitelist only certified implementations (which doesn’t necessarily exclude free software implementations), because they get blamed for poor voice performance (drops, noise, other issues).
This hurdle would have to be passed as well.
Again, I can see this happening, but not in the near future.
As it stands, there are no open implementations even for android which relies solely on proprietary baseband-firmware in combination with proprietary userspace support.
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I really don’t know my low-level stuff very well, so this is a genuine question: Is there something more to VoIP that would require VoWifi to exist separately?
There are at least some open source implementations of VoIP, though whether they are any good is beyond me
I’m not sure I fully understand your question, but VoWiFi is a type of VoIP. VoIP is the general concept of conducting voice calls over an IP packet data network, and VoWiFI is an example of a specific VoIP standard. Other examples of VoIP standards or platforms include SIP, Matrix, Discord or Skype. Each requires a different implementation. Some are based around service providers that insist on non-free software. VoWiFi is the standard used by cellular carriers for seamless VoIP using your cell phone number. Its integration with the cellular network makes it more complicated to implement.
That was my suspicion. You seem knowledgeable enough to confirm it. It’s interesting that VoLTE may be easier to support than VoWiFI. Good post, thanks!
Well, VoIP is just a very generic term describing the transport of voice over a IP-based connection, it doesn’t necessarily describe specific technology.
It tends to be used most often for SIP-transmissions, which would include VoWiFi in a broader sense.
Where VoWiFi differs is the tight integration in the modern carrier-grade telephony system called IP Multimedia Subsystem, aka IMS.
IMS has a lot of extra complexity, and there are basically 2 reasons for that:
- Integration into Carrier-Networks (including legacy support)
- Overall Quality
VoWiFi is expected to be very reliable, which includes a lot of roaming scenarios, it will allow better location functinality for emergency services (when you call 911, 999, or 112 or whatever your country is using), and it has a tightly integrated Quality-of-Service functionality.
The classic example would simply be support for roaming between mobile networks and your home WiFi, in which case a traditional SIP call would drop, Skype and others will either drop or at least severely lag, and in a proper VoWiFi situation neither party would notice.
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Generally that is not actually the case, however, if the VoLTE implementation in a baseband is used and the application-processor uses separate WiFi hardware, VoLTE is indeed easier done, because you don’t have to care to implement it yourself, the baseband handles it and you just interchange PCM audio with between BB and AP.
In his interview with Bryan Lunduke back in August 2017, Todd Weaver stated that the Librem 5 can be used for Wi-FI calling. That discussion is at about 12:00 into the interview.
Wi-fi calling across the matrix client I would assume. Not wi-fi calling through a carrier service. When I saw this thread, I thought the same though: Why would I want to call over wi-fi through my carrier who will charge me to use this feature, when I can just use the wi-fi I’m already paying for to make VOIP calls using software that supports that?
I have strong preference of using VoWiFI rather than other VoIP types (Matrix, SIP, whatever) because of the following reasons:
- my carrier plan has flat rates to landlines and to all other mobile carriers in my country
- I’m living very close to the border (couple of hundred meters) and my carrier’s signal is really bad in my apartment. I’d really really benefit from VoWiFi because it would mean a better call quality and no dropping signals and/or calls. People could reach me without using an extra client or number. They’d just need one number from me and would always reach me on the same device.
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Too bad a Skype Out number is a no go for you, as that would fix your problem as well.
Skype Out doesn’t help people reaching me. And Skype In would mean a) interrupting calls when changing networks (mobile to wifi or vice versa) and b) eating away from my monthly data volume when not in a WiFi.
And Skype being proprietary is a show stopper anyways.
The fact is that the Librem 5 will be usable both with and without the facility to make calls via a cellular network. WiFi calling is a useful supplement to cellular calling. It’s a bit like having a femtocell in the building.
It would make no sense for me to use internet-based VoIP services for PSTN calls. I will already be paying for the ability to make and take calls via the cellular network, because that comes as standard with the most cost effective cellular data services. That includes the ability to use WiFi calling on supported handsets. Not only is the cellular voice call service effectively free of charge with my data connection (I can’t save any money by avoiding it), but it is also more robust to poor cellular signal conditions than VoIP over cellular data.
Given that I will already be subscribed to the ability to use WiFi calling whether i use it or not, being able to make use of it via a compatible handset will always be an advantage.
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Sounds like a fun/interesting project to take on.
If the SIM is accessible from the OS on the device, then it seems that it would be possible to build an implementation. What is unclear to me (but may be cleared up reading the relevant standards) is if the call is just data on the cellular side. If it is, then moving from wifi<->cell should be possible. If not, then I suspect the hardware would require some special support for it.
Either way, I wouldn’t expect it to be included in the initial release. My understanding is that the initial release will be just the basic functionality needed to call it a phone. (Think Android 1.0, or possibly less.)
One, possibly interesting, follow on question. Has anyone looked at the source for the Ubuntu phone to see if it supported UMA/GAN? That might direct us to some existing open source software that implements the standards, which would make supporting it MUCH easier.
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I looked for mentions of UMA/GAN support in Ubuntu Touch. I found a mailing list thread from 2013 requesting the feature.
In my experience it’s only in the last two or three years that WiFi Calling really emerged as a feature commonly supported by carriers and phones without having to install special apps, so it would have been very low priority for Ubuntu Touch back in 2013, I imagine.
This September 2018 Ubuntu Touch Q&A includes the question “Can we add wifi calling to UT?” It sounds like nobody has attempted it and a perceived lack of standardisation is seen as a barrier to developing it, but apparently LineageOS supports it.
It would not surprise me if, in the case of LineageOS and Ubuntu Touch and Android, it’s more about interfacing to baseband chipset implementations of VoWiFi rather than writing a full implementation from scratch. If you are already using a highly-integrated SoC containing baseband/WiFi/application processor/VoLTE/VoWiFi/kitchen sink/back door/cat flap/etc/etc you might as well make use of it to avoid having to develop your own implementation. (The Librem 5 is not going to use that kind of SoC.)
DID anyone manage to get wi-fi calling to work ?
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