Of all the big changes we’ve seen in mobile over the last decade, one of the biggest has been the move from 3G to 4G networks. And now a similar transition, the shift from 4G to 5G, is driving another acute change in the mobile industry: As mobile operators begin to shut down their older 3G networks to create more spectrum for 5G, they’re losing their capability to connect with operators that don’t have the voice-connecting technology known as Voice over Long Term Evolution, or VoLTE roaming. This will have profound ramifications for many operators’ roaming business that is creating an urgent need for a new industry solution. Let’s take a closer look.

A Quick Look at VoLTE and Roaming

The migration to 4G involved numerous technical challenges, as complex network kinks had to be worked out, new signaling and receiving equipment installed, and mobile devices made with the necessary hardware. Among these challenges was how to seamlessly transmit voice service from 3G to 4G, which had to be sent separately from data. Enter Voice over Long Term Evolution, or VoLTE. This technology enabled voice and data service to be used simultaneously and eliminated the need to have voice and data service on separate networks.

Syniverse has been right in the thick of VoLTE since it was first developed, and we became an early leader in a core component of VoLTE – roaming. Over the last 10 years, we’ve been working with mobile operators to test, resolve and ensure the quality of a number of new VoLTE processes among different networks across a range of geographic regions.

New Tech Era, New VoLTE Challenge

Now, however, a need for a new VoLTE roaming solution has rapidly emerged for the mobile industry: As operators begin to shut down their aging 3G networks to create more spectrum for 5G, among other reasons, they’re losing their capability to connect with operators that don’t have VoLTE, which is a majority of them.  

In my role in managing various VoLTE projects, I’m increasingly asked by customers and colleagues about this challenge and what it means for the industry, and below I share some of the most common of these, beginning with a refresher on what VoLTE is. I hope these insights shed light on this quickly rising problem for our industry and help us to move closer to a solution, and I invite you to share your questions or thoughts on this challenge in the comment section below.   

What is VoLTE?

Simply put, VoLTE is a way to route voice traffic over 4G LTE networks that mobile operators use for transmitting data. VoLTE uses an internet technology called VoIP, or voice over internet protocol, to deliver both voice and multimedia over internet protocol networks. With the rise of 4G, about 10 years ago, VoIP became an extremely important technology for bridging the analog voice service of 2G and 3G networks with the digital format of 4G.

What are VoLTE’s biggest benefits?

One benefit is its ability to allow users to make voice and data calls on 4G networks simultaneously, enhancing the user experience. Under previous methods, for a user on a mobile network, data could only be transmitted to or from a 4G network when the user wasn’t currently engaged in a voice call.

On a related note, a second benefit of VoLTE is that it allows operators greater network efficiency, because it eliminates the need to have voice service transmitted on one network and data service on another. A third benefit is that it allows users higher-quality voice service, because calls can be transmitted in a high-definition format.

Finally, call setup time is much faster than with older technologies. Traditional ISUP (Integrated Services Digital Network User Part) calls may take three to four seconds to set up while VoLTE takes only one to two seconds.

What is the situation that has developed now with operators and VoLTE?

One situation in particular is that operators need more spectrum. The growth of 5G has put pressure on them to free up current spectrum so it can be dedicated to supporting this new network deployment. At the same time, another situation driving a need for more spectrum is that operators are looking to streamline the management of their older 3G network equipment to simplify technical complexity and achieve greater operational efficiency. In parallel, operators are also attempting to reduce overall capital and operating expenditures related to these older networks.

As a result of these situations, operators are looking to shut down their older networks. However, when they do this, they lose the ability to have a roaming partnership with the operators that don’t have a VoLTE capability and depend on direct 3G to 3G connections to have roaming partnerships with other operators. Unfortunately, this lack of a VoLTE capability is still the case for a majority of operators, and many of these operators still do not have plans to integrate VoLTE anytime soon.

What does this situation mean for operators shutting down their 2G and 3G networks and consolidating their services on 4G and 5G?

An acute need arising for 4G- and 5G-only operators is for them to be able to connect to the operators that don’t have VoLTE roaming and don’t have plans to integrate it. Without the ability to connect to non-VoLTE-enabled operators, 4G- and 5G-only operators stand to lose a great amount of their roaming partnership business, since most operators still don’t have VoLTE. Importantly, by losing this voice service business with these non-VoLTE operators, they also lose data service business as well. This results in lost roaming business for operators as well as less roaming market competition for consumers, which means higher roaming rates. It’s a lose-lose scenario for everyone.

What solution is the industry developing to address this challenge now?

Syniverse for one is working on a solution that would allow 4G- and 5G-only operators to support 3G fallback for voice calls so that these calls could be made via VoLTE. This would, for the first time, allow users on non-VoLTE networks to seamlessly make VoLTE-powered calls. Importantly, the solution is intended to allow the non-VoLTE network operators a way to roam without either side having to make a major technology upgrade. If you would like more information on VoLTE roaming, send a request to us at blog@syniverse.com.

As 4G – and, soon, 5G – continues to move toward becoming the standard for mobile service, users will increasingly expect access to the same rich, real-time experiences all the time, wherever they go. We look forward to helping the industry deliver on these expectations through the development of this new VoLTE roaming solution and other network connectivity solutions.