Mission-critical communications are at the heart of public safety and emergency response. Police, fire brigades, ambulance services and other first responders depend on reliable voice, video and data services that need to work when lives are at stake. For many years, these services were delivered over legacy narrowband land mobile radio networks using a range of technologies. As countries begin to retire these networks and move to standardized 4G and 5G-based solutions, mission-critical services are entering a new era.
This transition brings significant new capabilities, but it also creates a fundamental requirement: devices, applications and network implementations need to work reliably together. That’s where standardized conformance testing plays an important role.
Why conformance testing is essential
Conformance testing provides a common way to verify that implementations meet agreed 3GPP requirements. For mission-critical services, this helps create confidence that products from different vendors can operate as intended in increasingly complex, multi-vendor deployments.
3GPP RAN5, the working group responsible for UE conformance testing, has included mission-critical services in its work since Release 13. The initial work focused on client-side testing over LTE, covering mission-critical Push-to-Talk (MCPTT), mission-critical Video (MCVideo) and mission-critical Data (MCData).
For some time, however, adoption of the tests was limited. That began to change as nationwide mission-critical deployments matured and more countries started planning the transition away from legacy systems.
The growing importance of standardized mission-critical testing was particularly visible in the US, where FirstNet, the independent US government authority, works with its operator partner AT&T on a nationwide public safety network based on 3GPP technologies. In Europe, meanwhile, several countries have been preparing to replace legacy mission-critical systems as existing contracts approach their end dates.
The introduction of 5G support for mission-critical services in 3GPP Release 17 added further momentum. As operators and vendors prepared for 5G deployments, there was a growing need to ensure that the associated conformance test specifications were ready as well.
Extending testing across 4G and 5G
The move to 5G meant more than simply adding new radio technology to the existing test framework. Release 17 also introduced enhancements to mission-critical services, requiring the conformance specifications to cover the functionality defined in the updated service specifications.
These enhancements included updated group handling mechanisms and the introduction of an MCData Notification Channel. Both required corresponding additions and updates to the conformance test specifications to ensure that the tests covered the functionality defined in the Release 17 service specifications.
One important outcome was the creation of the TS 37.579-x specification series. Earlier mission-critical conformance specifications were part of the TS 36.579-x series and were tied to LTE. With the introduction of 5G and the need to support multiple radio technologies, TS 37.579-x was created to cover mission-critical services across both LTE and NR.
This change also makes the test specifications more efficient to develop and maintain. Because the new series can cover multiple radio technologies within the same specification, a new conformance test case can in many cases support both 4G and 5G without requiring duplicate work. For operators and vendors moving from legacy systems to 4G and 5G, this provides a more consistent basis for verifying mission-critical implementations across technologies. The 37 series is also “6G-ready” in the sense that it can naturally evolve to cover 6G as well.
From client-side to server-side testing
There is another important evolution taking place in mission-critical conformance testing: the scope is expanding beyond the client.
Traditional RAN5 conformance testing has focused on user equipment. But real-world mission-critical deployments also depend on the behavior of servers and applications, particularly in control-room environments.
A control-room application, for example, can run on a UE or workstation and perform functions that go beyond those of a conventional client. It may interact with the core network and mission-critical servers, manage groups, and distribute voice, video and data. In off-network and hybrid scenarios, the distinction between client and server can become even less clear.
The industry therefore identified a need for standardized testing of server-side mission-critical functionality, including interoperability between mission-critical servers and interconnection between different mission-critical networks.
There was, however, a structural obstacle. The RAN5 Terms of Reference had historically focused on conformance testing of user equipment and did not explicitly cover server-side testing.
Responding to industry requirements, Ericsson worked with other mission-critical companies to update the RAN5 Terms of Reference. The change was carefully scoped to allow server-side conformance testing for mission-critical services while avoiding overlap with areas covered by other 3GPP groups and testing frameworks. This opened the way for RAN5 to formally include server-side mission-critical conformance testing alongside client-side testing.
Ericsson has contributed to this work across the relevant 3GPP groups and has served as rapporteur for the Release 17 RAN5 mission-critical Work Item. The company is also rapporteur for the Release 18 client-side and server-side mission-critical Work Items.
Beyond its Work Item rapporteur roles, Ericsson is rapporteur for MCS-related test specifications in the RAN5 37.579-x series, with the exception of the TTCN implementation specification, which is handled by ETSI. Ericsson also leads a group of RAN5 delegates contributing to the mission-critical Work Item, coordinating a multi-company effort that reflects deployment scenarios ranging from nationwide public safety networks in the US to large-scale operator and vendor implementations worldwide.
A key milestone was reached when the European Telecommunications Standards Institute (ETSI) and a test equipment vendor verified the first 5G mission-critical test case in RAN5. Together with the work to expand the scope of RAN5 to include server-side testing, this helped establish a more comprehensive conformance framework for mission-critical services.
The result is a more complete approach to conformance testing that reflects how mission-critical systems are actually deployed: not simply as communication between a device and a network, but as interconnected systems involving clients, servers and applications.
From conformance testing to certification
Conformance specifications provide the technical basis for testing implementations. Certification can take the next step by providing an industry-recognized framework for demonstrating that products meet those requirements.
This is where the Global Certification Forum (GCF) comes in.
GCF provides industry-agreed certification programs for mobile and IoT products. Its certification processes use validated 3GPP conformance test cases to assess whether products meet defined requirements.
For mission-critical services, Ericsson has supported the introduction of a dedicated GCF certification scheme covering both 4G and 5G. The scheme builds on the mission-critical conformance work carried out in 3GPP RAN5, providing a path from standardized test specifications to product certification.
Ericsson has also been accepted by GCF as a Third Party Assessment Capable Entity (TP-ACE) for mission-critical certification. A TP-ACE is a GCF member company recognized as having the technical competence to determine the certification requirements applicable to a product and assess the product against those requirements.
As a TP-ACE, Ericsson participated in the first official certification of a mission-critical client under the GCF MCS certification scheme. This provided an early demonstration of how the RAN5 conformance specifications can feed into a practical certification process.
The relationship between the two frameworks is important. 3GPP defines the technical standards and conformance test specifications, while GCF provides an industry certification framework through which products can be assessed against the relevant requirements.
What this means for the mission-critical ecosystem
The evolution of mission-critical conformance testing has practical implications for operators, vendors and public safety organizations.
Standardized test specifications provide a common benchmark for implementations of MCPTT, MCVideo and MCData, helping reduce ambiguity and improve interoperability in multi-vendor environments. Extending the specifications to support both LTE and 5G also provides a more consistent testing framework as operators transition between radio technologies. The TS 37.579-x series is designed to accommodate multiple radio technologies rather than requiring the same work to be repeated separately for each one.
Bringing server-side implementations into the scope of mission-critical conformance testing provides a more complete view of system behavior. Testing can address not only what happens on the user's device, but also functionality that is increasingly important in control rooms and complex mission-critical deployments.
The GCF certification scheme provides a structured way for products to demonstrate compliance with defined mission-critical requirements. Together, standardized conformance testing and certification can give operators and public safety organizations greater confidence when evaluating products and planning deployments.
Looking ahead
Mission-critical communications will continue to evolve as more countries move from legacy systems to standardized 4G and 5G technologies. Conformance testing needs to evolve with them. New functionality, new deployment models and the growing role of server-side implementations all create requirements for test specifications that accurately reflect how mission-critical services are delivered. The continued development of the TS 37.579-x series and the GCF mission-critical certification scheme will help support that evolution.
Ericsson’s work in 3GPP RAN5 and GCF is part of a broader effort to help ensure that the standards, test specifications and certification frameworks keep pace with the needs of the mission-critical communications ecosystem.
For public safety organizations, operators and vendors, the goal is straightforward: as mission-critical services move onto standardized 4G and 5G networks, these services and systems need to work reliably across the entire ecosystem. Robust conformance testing and certification are important tools for making that possible.
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