VoLTE and Wi-Fi calling not as widespread as we think

VoLTE

Most recent smartphones support VoLTE and Wi-Fi calling. It now appears that the vast majority of MVNOs using Telstra, Optus, and Vodafone networks can’t access it.

VoLTE, sometimes called HD Calling, began with the Apple iPhone 6, Samsung Note5/S6, LG G5 and Google Pixel. Today it is a feature of OPPO, realme, vivo, Nokia, Motorola, Telstra white-label phones and most others with Australian certified carrier firmware.

What is VoLTE?

It simply means the smartphone can make a voice call over 4G data-only networks. It converts voice to digital ‘packet switched’ data and uses SIP (session initiation protocol like Skype) to transmit voice over data. If you don’t have VoLTE access, all your calls (and most likely your data) will be over the far slower 3G network. As it is carrier dependent it requires your smartphone to be running Australian firmware. Grey market and parallel imports may be VoLTE capable but will not join the Australian network.

Which Telco Carriers have VoLTE?

Telstra has the capability except where the area may be using certain types of small cell repeater. Optus has it for its post-paid (not pre-paid) customers in capital cities. On 10 July 2020, Optus announced that it would extend VoLTE to its MVNOs (mobile virtual network operators) for their post-paid customers.

(Update: Moose claims it has VoLTE – it was the first on the Optus Network)

Vodafone has conducted trails, and it is available to its post-paid customers.

VoLTE

What is Wi-Fi Calling?

Wi-Fi calling or Voice-over-Wi-Fi (VoWiFI) means that the call or SMS goes over the NBN. To be clear, if you can’t get a VoLTE service, you can’t use Wi-Fi calling. Telstra has also moved all its consumer customers to pre-paid and removed Telstra Air, so don’t rely on getting it via Telstra Air either.

Wi-Fi Calling is part of VoLTE and makes staying connected easier when mobile signal is limited, and there is an available Wi-Fi service. It is particularly useful indoors and solves coverage holes in areas where mobile signals can struggle to penetrate. But the catch – Unless your NBN comes from the Telco with your mobile account, you will pay for the NBN data usage. Still, as most have unlimited NBN, this is not a big issue. VPNs are not supported. You can read more about Telstra VoLTE on the Whirlpool Wiki here.

Which carriers have Wi-Fi calling?

VoLTE works on carrier reserved bandwidths that don’t compete with their 4G/4GX networks. In general, Telcos don’t provision VoLTE or Wi-Fi calling for MVNOs as they lack that bandwidth. Boost has Wi-Fi calling as it uses the Telstra retail network (same as Telstra) bot no other Telstra MVNOs have it. Interestingly Telstra-owned Belong does not have it. Amaysim, now owned by Optus, does not have it, although we expect it would gain access soon. No Vodafone MVNO has it.

GadgetGuy’s take – a great idea but hobbled by Telcos greed

When we review a phone, we always state, ‘VoLTE and Wi-Fi calling are carrier dependent’. Sorry, we assumed that it was more universally available via MVNOs. It is not. VoLTE and Wi-Fi calling are carrots reserved for the highest-yield Telstra, Optus and Vodafone post-paid customers. I spoke to Woolworths Mobile that stated that as it was now Telstra’s second-largest MVNO it required access to 5G, VoLTE and Wi-Fi calling sooner rather than later. Discussions are ongoing but don’t hold your breath.

Disclaimer: I have asked Telstra, Optus, and Vodafone to fact check our desk research results.

  1. So what happens when people travel from Overseas with non-Australian firmware phones? Will they not ever be able to make a standard call?

    1. Australian firmware means that it must be activated here first then it can roam OS. A grey market phone means it must be activated first OS then you can roam here.
      But 5G is different as the IMEIs numbers are first locked to Australian telcos so a grey market won’t get 5G unless it was first activated OS. VoLTE only means you can make a voice call over 4G (which is data only). If you don’t have VoLTE then the call can only be made over 3G until that network is turned off here in 2024. Let me know if you have a more specific question.

      1. I think there is certainly confusion here. Have a listen to Trevor Long EFTM podcast just released today. The first callers question was about VoLTE on a Zenfone 8. Trevor said that any phone can do calls on 4G, it doesn’t necessarily have to be VoLTE compatible. Not sure if that’s right or not, and if not maybe can you provide the right answer. Hence going back to my first question, i’m asking more in the context of overseas travellers coming to Australia with their Overseas phone. If the its right that you can’t make a call once 3G is turned off unless the carriers have approved VoLTE, then I assume its all going to have to open up to all phones post 2024 ?

        1. Trevor is technically wrong – practically right. In order to make calls on 4G, the Telco and phone must have VoLTE (Voice Over 4G LTE). For the most part, modern phones support VoLTE but there are many global carriers that do not. Their logic is that voice calls should be on 3G and data on 4G. Australia is switching off 3G progressively until 2024 and so its three carriers all have VoLTE enabled. Many other countries will have 3G networks for a very long time to come. So if 3G is not available you should be able to use VoLTE.

  2. With Telstra turning off 3G in Mid 2024, I would assume that they will be forced to allow the MVNOs to use the VoLTE and VoWiFi functions in the coming years.

    1. We are currently researching this issue. Telstra is sneakily calling the repurposed 3G as Low-Band 5G. The short answer is that the Telco’s will have to open up VoLTE, VoWiFI and HD calling to MVNOs before 3G goes down. I will be extremely sad to see 3G go as it really is the backbone of Australia’s voice network and VoLTE is not really a 100% substitute.

  3. I read this somewhere:

    HD Calls Limitations
    While VoLTE calls provide higher definition calls, this feature is limited to calls only made between two VoLTE enabled handsets. If one handset is VoLTE enabled and the other is not, then the call will be of standard quality and not HD.

    Does this mean that VoLTE does not benefit audio quality in anyway. Or does it still have benefits over 3g voice.

    Thanks

    1. It is all a little. VoLTE is about using 4G LTE (a data-only digital service) for voice calls. The receiving set does not need VoLTE as the tower takes care of sending the signal to them in a form their phone accepts. For the most part 3G is still sued for calls although that bandwidth is being repurposed and will eventually disappear. HD Voice is a function of Wi-FI calling (which is a sub-function of VoLTE) and only works if both ends have HD VOice.

  4. I have asked amaysim support about why (unlike Moose Mobile) they don’t currently support VoLTE and VoWiFi). Their answer was: “We are still waiting for a green light from Optus for 5G Technology. Once we’ve offered 5G, WiFi calling is one of the many features we will offer. We will also offer Unlimited plans which are exclusive only for 5G Technology.”

  5. No VoLTE for Telstra B28 only locations?

    That’s a big call.

    see https://exchange.telstra.com.au/small-cells-bringing-fast-mobile-coverage-needed/

    Plenty of locations with B28 only like Adventure Bay.

    see https://web.acma.gov.au/rrl/site_search.site_lookup?pSITE_ID=10004594

    And what do Telstra say …

    ” At Adventure Bay on Bruny Island off the coast of Tasmania, for example, we’ve installed a small cell at the beach to allow visitors to share pictures and videos on social media, as well as to make calls and send messages to friends and family around the world.”

    1. Hi John
      While doing the research we found this reference to small band 28 cells that are designed to transmit no data further than 400 metres from the cell. “Due to constraints with the backhaul it is not intended to support data heavy Gigabit LTE, VoLTE, VoWiFi, … And technically VoLTE does not use band 28 but a band separate from it – part of bands 1 or 3. It could be that Bruny Island (lovely place) has 3G coverage for voice calls. We will keep looking to see if we can find more. Thanks – we aim to be accurate.

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