What is Voice over 4G, why are we trialling it and what difference will it make to you? We've been speaking to the man in the know to find out.


Some of the changes we make to our network are hard to miss. Our 4G rollout, for instance, is not only making headlines, but it’s a gear shift that your phone will feel the benefit of right away. Some of our network tweaks are less immediately obvious, though, and Voice over 4G is one of them.


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What is Voice over 4G? It’s the next step in our pursuit of more reliable, consistent and high quality calling, which we hope will also improve your battery life, and it’s something we’re trialing right now in our labs. We’ve been chatting to Vodafone’s Ed Cowmeadow to find out more…

Understanding Voice over 4G

To understand what Voice over 4G means for you, we first need to understand exactly what it is and why we’re trialling it. “Voice over 4G is also known as VoLTE – that’s Voice over LTE – and it’s the next evolution of our voice service,” Ed explains. “It’s essentially connecting calls via our 4G network. 4G today only supports data, so when you make a call your phone connects via 3G or 2G by default. So Voice over 4G, is us being able to carry voice traffic over our data network, rather than the radio network that normally carries them.” And, as Ed reveals, it’s pioneering stuff:

“We’ll trial it first with our own employees, just like we did with 4G.”

“It’s something that’s been present in the industry for quite a few years but there are very few operators around the world to have launched it – certainly no one in the UK. That’s because the idea of moving voice calls over to the data network is a pretty complicated thing to do.

“There are a number of historical services that we need to re-tune to work on the data network. So we’re trialling it in the first instance to make sure that we do it right.

“We’ll trial it first with our own employees, just like we did with 4G. Before we turned 4G on for the public in August 2013, we had a number of friendly users at our HQ campus at Newbury and in certain areas in London testing the service. That’s exactly what we’re looking to do with Voice over 4G.”

The quest for faster, smarter calling

So if Voice over 4G is all back end network stuff and it’s only at the trial stage, why are we telling you about it? Simple: because when we roll it out across the UK, you’ll notice the difference in a couple of ways. Ed explains…


“You experience a slight delay when initiating a call as a 4G user in a 4G area because your phone will need to switch to 3G to make or receive a call. It’s the same for customers of all of the UK’s 4G operators, and that’s why we’re running this trial – to find out how we can make things better.

“When we have the Voice over 4G capability, the call set up times should be much quicker, particularly when you’re calling someone else on 4G.”

Better battery?

All of that’s great, but there may be an additional benefit as Voice over 4G could improve your phones’ battery life too…

“3G can be pretty battery hungry when it comes to calls,” Ed tells us. “I regularly hear people talking about the old brick of a phone they used to have that had a battery that lasted for days. Sure, phones do more these days but 3G does need more power than 2G and both things combined can increase battery drain. By comparison Voice over 4G is a pretty efficient technology, and that means you may well see your battery life increase when it’s available.

“4G has been designed from the ground up to be more efficient…”

So the hope is that 4G will not only provide faster internet access, but it will also be less power hungry for calls at the same time? It sounds too good to be true, but Ed explains that it’s because 4G tech has been designed from the ground up to be more efficient.

“Modern mobile network technologies use certain ‘modulation schemes’ to transfer data and this means 4G has a much greater ‘spectral efficiency’ than 3G or 2G. Put simply, it means you can do more in a shorter period of time because of the way 4G maximises the use of the radio resources.”

Voice over 4G trials are already underway in Vodafone’s test labs. Stay tuned for more news when we get it.

The science behind 4G: How do we go about bringing 4G to new cities and towns? Click here to find out what happens when we make the switch.