While there have been rumblings in the industry about 5G roaming – and even a recent 5G roaming launch by Smart Communications – the simple reality is that the telecom industry is not at a point where a 5G roaming launch could be maximized to its fullest capacity. Of the 800 operators that have rolled out LTE/4G, 250 have launched VoLTE (voice-over LTE) for their customers. Only 37 of those have launched VoLTE roaming. As mentioned in previous blogs, VoLTE network launches are critical as 3G turndown nears and Standalone (SA) 5GC roaming is not anticipated in the near term due to complexity.

Before the industry jumps to 5G roaming, we need to ensure VoLTE roaming is solidified and there is plenty of gas left in the tank for LTE and VoLTE roaming.

VoLTE, on its own, plays a key role as it allows for the decommissioning of legacy circuit switched (CS) networks given that voice services can migrate to LTE networks. The stakes are equally high for VoLTE roaming. As operators discuss their plans to turn off their 3G networks, VoLTE roaming needs to gain broader traction to confidently decommission legacy CS networks.

Verizon made news recently by announcing that it would turn off its last 3G CDMA network at the end of 2022. Other operators will likely follow suit. Without a functional alternative for roaming when 3G networks are finally turned off, operators will lose their circuit switch fallback footprint, leading to an awful and inconsistent customer experience that will force subscribers to use over-the-top (OTT) applications or Wi-Fi calling to make voice calls while traveling.

While the Global Systems for Mobile Communications Association (GSMA) is monitoring the different operators’ 3G shutdown dates and encouraging operators to launch VoLTE roaming, the truth of the matter is that launching these networks is challenging given issues with handsets and device testing across continents.

Testing Challenges

One primary consideration an operator needs to be mindful of when launching VoLTE roaming networks is handset models. Currently, there are 2,000 VoLTE handset models in the ecosystem. The issue with these devices lies in the OEM settings, specifically in terms of turning VoLTE roaming on or off. When these settings are not properly adjusted for operators’ home subscribers and roaming subscribers, it inhibits the operator’s ability to conduct tests of how the handset will perform in the real world rather than a lab environment.

Another challenge comes in the form of costs related to international testing due to the need to test handsets for correct IMS configurations specific to the HPMN. Operators have hundreds of partners that need to test the roaming on these devices. That can require operators to deliver two $1,000 VoLTE configured devices plus SIM cards to each partner per VoLTE roaming launch. It is a process that spans continents and poses logistical and scalability nightmares.

Operators have relied on 3G and LTE roaming due to these issues. The threat of 3G networks shutting down for good should serve as a much-needed push for operators as it is becoming increasingly difficult to justify the lack of investment in VoLTE roaming. Yes, VoLTE roaming launches can be challenging, but there are best practices and key lessons learned to help facilitate a smoother launch process.

Launching VoLTE

TNS has been particularly successful with its VoLTE launches. We have launched 17 individual roaming networks for eight different operators regionally across the US. The launches typically take 5-6 weeks to complete and have garnered some key discoveries. Success does not come easily, nor is it coincidental, but instead is a testament to TNS’ proven ability to successfully solve problems that challenge the entire telecom industry with mission critical communications.

In executing these launches, TNS has gleaned several valuable takeaways, including:

  • Android devices sometimes need manual network selection to attach
  • Not every operator uses IMS-enabled SIM cards. Operators have an incorrect assumption of thinking their old SIM cards are suitable for VoLTE when in fact they don’t work; instead, operators have to use SIM cards that are properly provisioned for IMS services
  • Operators also need a specific Quality of Service Class Identifier (QCI) value to support testing
  • TNS can help operators identify which QCI value they need to support as a served operator
  • The correct IMS stack or carrier bundle must be provisioned before testing to reduce failures and troubleshooting

In addition, the GSMA is also working on an online resource – a Known Issues list – for carriers to exchange knowledge on device and testing issues. The resource is a knowledge database designed to share learnings amongst operators so they can avoid having to start from square one on VoLTE launches. The GSMA’s VoLTE implementation guide covers some of the common launch issues as well.

Everything Happens Slower Than We Think

For a long time, it was expected that VoLTE roaming would be fully deployed by 2018. Three years later, we are not even close to that. And while there is a lot of noise about 5G roaming, operators that have prioritized VoLTE launches are not going to feel rushed to invest in another roaming launch. 5G roaming will be ubiquitous eventually, but for now, the industry needs to solve these handset issues and prioritize VoLTE roaming launches to be ready for widespread 3G turndowns.

To learn more about TNS’ VoLTE roaming launches, visit https://tnsi.com/product/volte-roaming/.

Nina is Director of Product Management at TNS, with specific responsibility for roaming product strategy and development. She can be reached at solutions@tnsi.com.