VoLTE Roaming

TOMIA’s Platform provides mobile operators with flexible solutions to efficiently operate and optimize VoLTE Roaming.


As VoLTE becomes more widespread, maximizing roaming margins, maintaining customer experience while traveling, and complying with regulations is increasingly challenging for mobile operators.

Margin erosion

As a VoLTE call is all data and is routed back home, the visited network is “service unaware”, and can identify it only as a data stream. Billing at a wholesale level is only possible on a per MB basis instead of minutes. This poses a challenge for the visited network considering that the CS (Circuit Switch) voice call can be 5 times more expensive than a VoLTE call, which can result in revenue leakage. In addition, although the home network will pay less for every VoLTE call because the traffic is home routed, it will be their responsibility to terminate these calls and bear routing costs.

Quality of Service

Unlike in traditional CS (Circuit Switch) voice service, in VoLTE, 17% of all local calls and 100% of calls to local short codes or toll-free numbers can fail. As traffic is routed home, the home network is required to analyze the dialed number and route the call to its destination. To address this requirement, network operation teams need to constantly track and provision frequent worldwide numbering plan changes. However, network nodes are not designed to cover the underlying complexity, and any missing information can cause degraded QoS and a reduced call completion rate.


In VoLTE roaming, signaling changes to a completely different protocol: from SS7 to DIAMETER. To comply with their regulatory obligations and general communications principles, operators need to know when their subscribers are traveling abroad and where they are landing. This is only possible with VoLTE enabled or supported tools. The inability to comply with welcome message regulations or to establish ongoing communication with the roamer regarding tariff information can be a showstopper when it comes to launching new roaming agreements.

Enable VoLTE Roaming with TOMIA’s Platform

With the 2G/3G sunset underway and the appearance of LTE only networks, operators that have not yet launched VoLTE roaming will not be able to support bilateral VoLTE roaming agreements and are at risk of losing global footprint.

Reduce VoLTE roaming risk

VoLTE roaming adoption is booming. Don’t miss the VoLTE opportunity — upgrade seamlessly to VoLTE Roaming with TOMIA’s End-to-End VoLTE Roaming platform.

Business Benefits

TOMIA’s VoLTE Roaming platform offers operators a complete end-to-end solution to take them through the journey of detection, agreement negotiation, network management, and settlement.

  • Eliminate margin erosion by paying less for every VoLTE minute
  • Increase revenue due to higher call completion rates
  • Ensure Quality of Experience with HD voice and shorter call setup time
  • Avoid billing disputes and prevent bill shock
Operational Benefits

The platform enables the implementation of steering policies and campaign strategies targeting VoLTE subscribers roaming in LTE only networks based on coverage and roaming service agreements.

  • Automatic detection of VoLTE capable handsets
  • Comprehensive worldwide numbering plan and correction rules
  • Comply with local regulations and avoid fines
  • Smart steering based on technology type and customer segmentation.

Use Cases

Steering of Roaming

Steering of Roaming

When steering of roaming is not optimal, there are real risks of margin erosion for operators and impaired experience for roamers. The average cost of a minute in circuit switching networks is up to 5 times more expensive than in VoLTE networks. VoLTE also improves customer experience with HD voice and shorter call setup time. TOMIA’s Intelligent Preferred Network (IPN) enables VoLTE steering by routing VoLTE-capable devices to VoLTE preferred networks, while providing smart recommendations based on commercial agreements performance.

Welcome SMS

Welcome SMS

Sparx, TOMIA’s campaign management tool, enables real-time detection of VoLTE-capable roamers roaming on LTE networks and triggers welcome messages to meet regulatory requirements. Personalized campaigns can be configured for various subscriber segments, including tariff information to avoid bill shock while encouraging roaming usage. Subscribers can also be informed when they are leaving an LTE network ensuring a seamless experience while travelling.

Call Completion

Call Completion

As VoLTE traffic is home routed, the home network needs to determine the dialled number as a home-local or geo-local number and translate it to an international format to complete the call. This is even more complex when it comes to emergency calls or short code numbers. By analyzing the roaming traffic in real-time, TOMIA’s VoLTE VHE service determines where and how the dialed number should be corrected based on smart algorithms and our vast numbering plan database and knowledge. Operators can gain international call payments that would be lost otherwise and avoid customer churn.



Operators can charge for their VoLTE calls per APN, or alternatively, based on QCI (QoS Class Indicator), where more differentiation is possible. TOMIA’s clearing services provide operators with the ability to charge different MB prices for the different QCIs. It also enables better planning of VoLTE Roaming enrolment by offering advanced forecasting and analytic tools and BI to help establish steering policies. This assists MNOs to select their VoLTE Roaming partners wisely.

Reduce VoLTE roaming risks, monetize the VoLTE opportunity and ensure subscriber experience.