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What is VoLTE?

VoLTE

VoLTE stands for voice over LTE and it’s more or less exactly what it says on the tin. It's voice calls over a 4G LTE network, rather than the 2G or 3G connections which are usually used.

We tend to think of 4G as mostly being about downloading, streaming and web browsing, and indeed that’s primarily what it’s been used for so far, but it can also be used to improve calls.

What are the benefits of VoLTE?

  • Superior call quality

The big advantage of VoLTE is that call quality is superior to 3G or 2G connections as far more data can be transferred over 4G than 2G or 3G. Up to three times as much data as 3G and up to six times as much as 2G to be precise, making it easier to make out not only what the person on the other end of the line is saying, but also their tone of voice.

Essentially it’s an HD voice call and it’s a much richer experience over all.

  • Improved coverage and connectivity

 VoLTE can connect calls up to twice as fast as the current methods and as 2G and 3G connections will still be available when there’s no 4G signal it simply means that there’s greater mobile coverage overall, as currently places with a 4G signal but no 2G or 3G means that on you can’t make or receive calls. 

Three_Super_voice

You might think that would be a rare occurrence, but some of the frequencies that 4G operates on, such as the 800MHz spectrum, have far greater reach than 2G or 3G spectrum, so you’ll be able to get signal further away from a mast or in buildings which other signals struggle to penetrate. Indeed, Three is fully relying on its 800MHz spectrum for VoLTE calls.

However, while 2G and 3G services would likely remain they wouldn’t be as necessary as they are now and much of the spectrum used for 2G in particular could potentially be repurposed to increase capacity on 4G networks.

  • Better battery life

Anyone who currently uses 4G could also find their battery life increased with VoLTE, as without it whenever you make or receive a call your phone has to switch from 4G to 2G or 3G, since 4G calls aren’t supported and then once the call is finished it switches back again. All that switching, plus the need to search for a different signal each time, can give the battery a significant hit.

  • Video calling 

It’s also theoretically possible to make video calls over 4G, much like a Skype call except you’d just use your mobile number and be able to use the regular dialler and call interface, so you can make and receive video calls from anyone else with VoLTE, rather than relying on separate accounts.

In fact you may have noticed that Skype and other existing video calls services often seem to have superior audio quality to voice calls. That’s because like VoLTE they use more data as part of a similarly named VoIP system, so you can expect your voice calls to start sounding more like Skype calls, but they won’t hit your battery life as much as Skype does.

Not only could video calls become native to the dialler, but other Rich Communication Services (or RCS’s) could as well, such as file transferring, real time language translation and video voicemail and there may be applications which haven’t even been thought up yet.

Are there any limitations of VoLTE?

It’s not available everywhere on every network, or on every handset, so you may or may not be able to use VoLTE – we’ve got more information on that below.

But assuming you can use it the only real limitation is that it won’t work when abroad.

Who offers VoLTE in the UK and how do I get it?

All the major UK operators offer VoLTE along with one MVNO (mobile virtual network operator).

In order to take advantage of VoLTE you need to ensure your phone is compatible and that coverage is available, so we recommend checking on the links provided to make sure you will be able to take advantage of VoLTE (4G Calling).

UK Networks offering VoLTE

Network

VoLTE

Availability

EE

Check compatibility

O2

Check compatibility

Three

Check compatibility

Vodafone

Check compatibility

iD Mobile

Check compatibility

  • Three

Three was the first and network to offer VoLTE, through a service dubbed 4G Super-Voice.

At its last update Three said it had brought 4G Super-Voice to 65% of the UK, but that was back in 2016, so we’d expect coverage is widespread by now.

However, unless you have an iPhone you need to have bought your handset direct from Three to use it, and even then not all phones are compatible with 4G Super-Voice, but dozens are, including the iPhone X, iPhone 8, Samsung Galaxy S8, Samsung Galaxy Note 8, LG G6, Sony Xperia XZ Premium, Huawei P10 and many more.

  • EE

EE meanwhile has a VoLTE service called 4G Calling, which is available everywhere on EE’s 4G network.

The service is only available on certain phones (and the selection is even more limited if you didn’t buy direct from EE), but most of the latest and most high-profile handsets are supported. 

  • Vodafone

Vodafone also has a VoLTE service called 4G Calling, but it’s not quite as widely available, as you currently need to be in one of these locations, including major cities such as London, Liverpool, Newcastle, Manchester or Edinburgh.

You also need a Samsung Galaxy S8, S8 Plus, S7 Edge, S7, Sony Xperia XZ, XZ Premium, XZ1, XZ1 Compact, Huawei P10 or P10 Plus bought from Vodafone.

  • O2

O2’s VoLTE service is also called 4G Calling, and it’s only currently available in London, Slough and Leeds on a handful of Sony, Samsung and Apple devices, such as the iPhone X, iPhone 8 and Samsung Galaxy S8.

Assuming you have a compatible phone, the latest software from your network and are in an area with VoLTE on any of these networks you should have access to VoLTE – it may not be available on all plans though and the availability regularly changes, so if in doubt check with your network.

How do I know if my phone supports VoLTE?

If you’re using a 3G handset then you’ll definitely need to upgrade, but if you have a newer 4G enabled one then it might work with VoLTE (though it will require a software update first).

In theory most existing 4G phones should work with VoLTE, but some may encounter problems and as they all require a tailored software update it’s dependent on each network to roll one out, so if you don’t have a new and popular phone then you may be left waiting indefinitely.

Check the lists and links above for the full range of phones that are currently VoLTE-compatible on each network.

Why haven't we been making calls over 4G with VoLTE all along?

The problem with Voice over LTE is that 4G LTE is a data-only networking technology, so it doesn’t natively support voice calls. While 3G and 2G were primarily designed with voice calls in mind and data was added to them.

As such it’s been necessary to create new protocols to support voice calling over 4G and it’s a big job, requiring upgrades across the entire voice call infrastructure. There’s no one standard for this, with different networks creating their own solutions.

There are some common problems and solutions though, most notably the requirement for Single Radio Voice Call Continuity (SRVCC), which simply means that the phone will be able to switch back to a 2G or 3G signal if you move out of a 4G signal zone during the call.

This needs to be seamless or the call will cut out, so it requires masts to pre-emptively deliver a 3G signal whenever the 4G signal drops dangerously low, but also to keep the 4G signal running at the same time, so it can either stay on 3G if it loses the 4G signal entirely or drop the 3G if the 4G signal becomes strengthened again.

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