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As operators scale into a 5G-first world, the complexity of interoperability grows just as quickly. New network architectures, sunsetting of legacy technologies and the rapid rise in standalone (SA) deployments mean operators need reliable, standardised ways to ensure their services work consistently at home and across borders.
This is why the expansion of the GSMA’s Interoperability Testing service to include a 5G Extension is so significant. This extended framework gives operators a single, trusted route to verify next-generation IMS-based services—reducing reliance on bilateral testing and helping the ecosystem scale with confidence.
In this blog, we explore why this matters for the ecosystem, how GSMA Industry Services brings unique value through its broader scope of testing and the ways in which our appointed verification partner, Mobileum, is supporting the rollout of this new unified verification capability.
The growing complexity of 5G roaming
Customer expectations for seamless connectivity haven’t changed—but the underlying technologies powering interoperability certainly have. With operators increasingly transitioning to 5G and retiring legacy networks, the risk of service degradation grows if testing isn’t done thoroughly.
GSMA Intelligence projects that 5G connections will reach approximately 5.5 billion by 2030. Consequently, ensuring voice continuity and seamless performance is no longer optional. Operators must verify that voice, data, IMS and next-generation capabilities all function correctly when at home or when crossing borders—or risk failures, reputational damage, customer churn and delayed partnership launches.
Why the industry needs a unified verification framework
Traditionally, operators validated service and roaming readiness through bilateral testing—an approach that becomes increasingly difficult as networks evolve, new devices are introduced and partner combinations multiply. With 5G introducing new variants, configurations and signalling paths, these bilateral processes simply cannot scale at the speed the industry now requires.
With VoNR (voice over 5G SA), operators face VoLTE-like interoperability challenges again—multiplied by new 5G Core/IMS integration, QoS policy and EPS fallback/roaming scenarios that can break call setup or voice continuity without consistent, industry standards-based verification.
GSMA Interoperability Testing (IOP), together with Mobileum’s VoLTE programme address this challenge by providing operators with unified verification capabilities that cover both non-roaming and roaming test environments. Originally designed for VoLTE/IMS interoperability, this now extends into a comprehensive 5G readiness verification path, enabling operators to validate end-to-end behaviour—whether on their own network or interacting across borders.
Instead of repeating bespoke tests for fragmented non-roaming and roaming test setups, operators can complete a single GSMA-approved verification cycle that assures consistent behaviour across devices, networks and roaming interfaces. This dramatically reduces time-to-market for advanced 5G services and simplifies the operational load across both home and roaming scenarios.
GSMA Industry Services plays a central role in this ecosystem, as an organisation delivering device, network and assurance services to customers globally. This breadth ensures that GSMA Interoperability Testing frameworks and test environments are not built for a subset of the industry—they are engineered for interoperability across all players, covering domestic and international use cases alike.
The broader testing scope of GSMA Industry Services
A key advantage of GSMA Industry Services lies in its cross-ecosystem coverage. It supports:
- mobile network operators
- device manufacturers
- the wider mobile ecosystem
The GSMA has adopted a comprehensive approach to interoperability testing—spanning network, roaming, and device scenarios—to ensure its frameworks accurately reflect real-world device behaviour, diverse network implementations and the evolving interoperability challenges of 5G. These frameworks are fully aligned with the GSMA Networks Group’s industry-standard testing regime for VoNR (NG.143), supporting consistent and reliable verification across the ecosystem.
Tyler Smith, Head of Industry Services at GSMA, emphasised the importance of this ecosystem-wide approach with the 5G extension:
This marks a significant step forward in strengthening end-to-end interoperability across the global mobile ecosystem, under a consistent and trusted framework.
By operating under the GSMA Interoperability Services umbrella, the 5G extension aligns device and network testing, reduces testing friction, improves reliability and accelerates the rollout of dependable next‑generation capabilities across all markets.”
How Mobileum supports this expanded testing capability
As an appointed verification partner, Mobileum brings decades of experience across roaming analytics, active testing and signalling intelligence. The company manages the end-to-end validation process, covering:
- test planning
- resource validation
- execution
- troubleshooting
- final reporting
This ensures that operators experience a streamlined and globally recognised route to verification.
Mobileum’s long-standing involvement in global interoperability programmes helps operators launch international services faster and with higher confidence. Its testing and analytics capabilities have historically helped safeguard roaming revenues, protect service performance and accelerate the formation of new partnerships.
However, while Mobileum is central to execution, it is the GSMA Industry Services’ testing framework itself that defines the scope, standards and methodology used globally. The GSMA sets the industry baseline: verification partners operationalise it.
Strengthening the future of global roaming
As 5G continues to reshape the mobile landscape, the industry needs shared frameworks that reduce fragmentation and accelerate progress. The GSMA’s expansion of the testing framework to include 5G readiness provides exactly that: a unified, ecosystem-wide verification path that ensures operators can deliver dependable non-roaming and roaming experiences globally.
Ultimately, this standardised approach helps operators launch new capabilities faster, isolate issues, reduce operational complexity and maintain service quality at home and across borders.
To learn more about how GSMA Interoperability Services can support your organisation’s testing and verification needs, explore the GSMA’s portfolio of services
