From Lab to Field: Best Practices and Challenges in Real-World 5G Testing

If you’re a software tester working in telecom, you’ll agree that 5G isn’t just another network upgrade. In fact, it represents a major shift in how networks are built, deployed, and experienced.

5G shifts us from fixed, hardware-heavy setups to agile, cloud-native networks built on virtualization, slicing, and edge computing.

While the development is exciting, it also requires a different approach to 5G testing. Traditional methods that work for 3G or 4G won’t be successful here.

But why is that so, and what do you do?

Don’t worry — this blog breaks down how to test 5G the right way with practical insights you can use right now. We’ll cover test scenarios that matter most, from roaming to device fragmentation to slice-level QoS.

Let’s start with a fundamental question.

What Makes 5G Testing Challenging?

In telecom testing, your goal isn’t only to validate whether a feature works. It also ensures it performs consistently across a highly dynamic and distributed network. Unlike earlier generations (3G and 4G), 5G increases complexity at every layer.

You’re testing in environments that are:

• Densely deployed: 5G requires more cells to deliver the same coverage, especially indoors, which complicates testing signal performance and handoffs

• Multi-vendor: The Core, RAN (Radio Access Network), and end-user devices often come from different vendors, each with their standards, implementation, and behaviors

• Dynamic and virtualized: With technologies like network slicing, cloud-native network functions (CNFs), and dynamic resource allocation, the infrastructure is constantly shifting based on traffic and policy

• Operating at new frequencies: You now deal with a much broader spectrum, including millimeter wave (mmWave) bands, which offer incredible speed but struggle with obstacles like walls, glass, or even heavy rain

On top of that, you still have to account for the massive variety of real-world usage conditions during 5G compliance testing, including:

• Heavy network congestion

• International roaming transitions

• Fluctuating bandwidth across different locations

• Signal interference from other devices or networks

• OS and device-level differences in how 5G is handled (modem firmware, power-saving modes, etc.)

Key Areas of 5G Testing

Here’s what to focus on that covers the entire 5G service lifecycle.

1. Device compatibility

Different devices interpret and react to the same network conditions subtly differently. In 5G mobile network testing, you have to consider:

• OS versions (Android, iOS, and custom firmwares)

• SIM configurations (eSIM, Dual SIM Dual Standby)

• Chipsets (Qualcomm, MediaTek, Samsung, HiSilicon)

• 5G radio capabilities (Sub-6 GHz vs mmWave, SA vs NSA support)

Real-device testing helps you catch issues that emulators or simulators might miss, such as:

• Handset behavior during dual connectivity (EN-DC)

• Differences in modem firmware handling beamforming or cell reselection

• Support for features like 256QAM, carrier aggregation, Voice over New Radio (VoNR)

2. Voice and messaging services

VoNR is quickly replacing legacy calling technologies, like Voice over LTE (VoLTE) and circuit-switched fallback (CSFB), in 5G standalone networks. Therefore, you need to test:

• Emergency call routing and priority handling (e.g., e911, EU112)

• SMS and RCS compatibility over IMS (IP Multimedia Subsystem)

• VoNR call setup time and success rates under variable network load

• Seamless EPS fallback to VoLTE or CS voice in NSA or coverage holes

Interworking between EPC (Evolved Packet Core) and 5GC (5G Core) must be verified to ensure seamless service continuity during EPS fallback or handovers.

3. Roaming and global coverage

5G roaming is a moving target, especially with spectrum, policies, and partner agreements differing across regions. Therefore, you must validate roaming transitions across geographies, network providers, and frequency bands.

Check whether the handoff is seamless. Does the user experience degrade? Your 5G testing efforts should also account for regulatory compliance, such as EU Roam Like at Home and regional support for VoNR fallback paths.

4. App performance and user experience

Determine how your app behaves under different network conditions.

• Does it crash under a low signal?

• Is the load acceptable on a congested network?

• How is the performance during handovers at cell borders and dense deployments?

• What’s the impact on video streaming, real-time gaming, AR/VR, or IoT apps?

User satisfaction often depends on what they see and feel, so when conducting 5G network testing, track metrics like touch response delay, buffering ratio, and Time-to-First Frame to measure experience quality.

5. Network behavior and Quality of Service (QoS)

Verify your network delivers consistent performance, even as end users move through different coverage areas or switch between network types (e.g., from 5G to 4G). Test metrics include network throttling, latency, jitter, packet loss, and throughput.

This is critical in areas with fluctuating signal strength or high device intensity. Don’t also forget to validate network slicing behaviors. Does the slice deliver the promised SLA even when under pressure? Is it isolated from other slices?

Types of 5G testing

What are the different ways you can run 5G tests? Let’s take a look.

1. Test lab and field testing

In the lab, you’re in control. You can:

• Reproduce and debug issues faster

• Simulate specific network configurations and edge cases

• Automate regressions and scale parallel testing across devices and OS versions

The best part? You can perform 5G testing without experiencing the chaos of the real world. The test lab is where you’ll typically start for RF conformance testing, protocol stack validation, or early-stage functional and interoperability testing.

Field testing is the exact opposite of that. It captures how 5G performs in actual deployments, such as the city center or dense indoor spaces.

It checks if handovers between cells are seamless when someone’s on the move. It’ll also help you discover device quirks that only surface in live networks.

The key is to run early-stage tests in the lab to stabilize builds, then validate in the field to ensure your app or feature is 5G-ready.

2. Virtualized testing

It’s the process of validating systems, apps, or network components running in virtual environments instead of physical hardware setups.

In the context of 5G, virtualized testing is essential because much of the network is built using Network Functions Virtualization (NFV), containerized network functions (CNFs), and other cloud-native architectural principles.

With this type of 5G wireless testing, you’re able to check the following:

• Do virtual network functions work across different hypervisors or cloud platforms?

• Does each virtual instance (e.g., a network slice or core function) get its fair share of CPU, memory, and storage?

• Are VNFs and CNFs being deployed, configured, and updated correctly by orchestration platforms such as OpenStack for VMs, Kubernetes for containers, and ONAP for lifecycle management?

In 5G testing, you can use simulation/emulation environments to:

• Create digital twins of your network for realistic traffic modeling

• Trigger edge cases (e.g., MEC node failure, slice SLA breach) without physical setups

• Validate CI/CD workflows by integrating automated regression tests into your pipeline

3. Hybrid testing

Modern telecom testing blends lab, field, and virtualized environments for full-stack coverage across controlled and real-world conditions. For instance:

• Simulate core behavior in a CI/CD pipeline using containerized 5G core components

• Use canary deployments to test new features or slices on a subset of users before full rollout

• Validate radio access features like beam management, handover strategies, and mobility patterns in both lab and field under varying load conditions

The goal is to catch edge cases early, shorten feedback loops, and reduce the cost of post-deployment bugs, critical in dynamic 5G networks.

Best Practices for Building a 5G Test Strategy

A strong 5G test strategy must be flexible, layered, and rooted in system-level understanding and user-level impact. Here’s what you should do:

1. Design modular, scalable test cases

Your test cases should be loosely coupled and easily adjustable so that they can be updated without rewriting logic — and more importantly, so that updates don’t break existing coverage.

Prioritize parameterization for scenarios like QoS Flow Indicator (QFI) changes, EPS/NR fallback conditions, and intra/inter-RAT mobility transitions to keep your suite resilient as the network evolves.

2. Tie metrics to experience and SLAs

It’s not enough to say your app works. In 5G testing, you must connect standard metrics like latency, jitter, and throughput to the actual user experience and SLAs. Therefore, thresholds for app responsiveness, call setup time, and slice performance under load must be defined. Use these as go/no-go indicators across test stages.

3. Integrate real-device testing early

Real-world device behavior introduces variables that simulators and emulators can’t model, like antenna placement, power modes, and modem firmware. When testing 5G, start with physical devices during early validation to surface fragmentation issues before they reach production.

4. Isolate and test slice-specific scenarios

It’s convenient to test apps or features as a whole. However, slice-level issues don’t show up until you directly look at isolation, prioritization, or preemption under stress. Build slice-specific test cases that simulate traffic contention, SLA degradation, or priority inversion across multiple devices.

Future of 5G Performance Testing: What’s Next?

As you look ahead, you’ll quickly realize 5G is just the beginning, and there’s so much on the horizon already, including:

1. 6G testing

Yes, it’s happening, and it’s in the early research phase. Although 6G testing won’t be mainstream for a few more years, we can expect to gear up for terahertz frequencies, AI-native networks, and even holographic communications.

Testing for features like sub-millisecond latency, context-aware networking, and integrated non-terrestrial network (NTN) connectivity will become the norm.

2. Cloud-native and software-defined

Networks are slowly transforming into software. You can test software-defined radios (SDR), virtualized network functions (VNFs), and containerized edge services orchestrated by platforms like Kubernetes.

Your test scripts, tools, and processes must also become cloud-native. Think DevOps, CI/CD, and infrastructure-as-code!

3. AI-driven, self-optimizing networks

The future of 5G and beyond includes networks that can optimize themselves based on real-time conditions.

You’ll need to validate ML-driven policy engines, monitor for bias, and ensure model explainability to maintain compliance and service reliability in autonomous networks.

Conclusion: Embracing the Complexity of 5G Testing

5G is not just faster — it’s fundamentally different. From its cloud-native architecture and network slicing to its reliance on virtualization and edge computing, 5G demands a complete rethinking of traditional telecom testing strategies. As a tester, this means adopting more modular, real-world, and slice-aware approaches that align with how modern networks operate.

Success in 5G testing comes down to preparation, adaptability, and a willingness to go beyond pass/fail results. You need to measure what truly matters: seamless user experiences, service-level reliability, and system-level resilience.

By combining lab, field, and virtualized testing with best practices like real-device validation, slice-specific coverage, and CI/CD integration, you can future-proof your testing strategy — not just for 5G, but for whatever comes next.

Because in this rapidly evolving landscape, testing isn’t just about finding bugs. It’s about ensuring innovation works where it matters most: in the hands of the user.

Source: This article was originally published on TestGrid.