Ensuring Mission-Critical Radio Clarity for Airport First Responders with GL VQuad™
For airport fire, medical, and security teams, radio clarity isn’t just a convenience—it’s a lifeline. This case study explores how an international airport used GL Communications VQuad™ and VQT to transform subjective radio complaints into objective, life-saving performance improvements.
Background: The Complexity of Airport Comms
Airports are among the most challenging RF environments in the world. Dozens of independent teams—from Air Traffic Control (ATC) to ground handling and fire rescue—must coordinate flawlessly.
As many airports modernise their infrastructure, migrating from legacy analogue systems to digital trunked (TETRA/P25) or LTE-based networks, maintaining end-to-end voice quality becomes critical. A single distorted transmission during an emergency on the tarmac can cause delays that impact safety and operations.
The Challenge: When Signal Strength Isn’t Enough
The airport’s engineering team faced a persistent issue: during heavy air traffic periods or emergency drills, voice quality between the control room and field responders would degrade. Users reported robotic voice, dropouts, and muffled speech.
Crucially, traditional network metrics like RSSI (Signal Strength) showed full coverage. The network “looked” fine, but it didn’t “sound” fine.
The team needed a solution that could:
- Quantitatively measure voice quality across the entire system (Dispatch to Field Radio).
- Emulate real-world voice traffic rather than simple test tones.
- Support both legacy analogue and modern digital interfaces.
- Provide Mean Opinion Score (MOS) metrics to benchmark performance objectively.
The Solution: Automated Voice Quality Testing (VQT)
The airport deployed the GL Communications VQuad™ platform paired with VQT analysis software. This allowed them to move beyond “Can you hear me now?” tests to scientific audio analysis.
How it worked:
- Simulation: VQuad™ connected directly to dispatch consoles and portable field radios, establishing automated call paths.
- Injection: The system injected standardised audio files (replicating human speech patterns) into the network.
- Analysis: The received audio was captured and analysed using GL’s VQT software, which applied POLQA and PESQ algorithms to grade the clarity.
- Mapping: Using VQuad’s GPS integration, engineers correlated poor MOS scores with specific physical locations—from runways to terminal basements.
The Results: Turning Data into Clarity
Within weeks, the engineering team generated a full baseline performance map of the radio network. The objective data revealed issues that signal bars had missed:
- Codec Mismatches: Intermittent configuration errors between gateway interfaces were causing compression artefacts.
- VoIP Jitter: Delay variations in the dispatch console IP link were leading to conversational echo.
- Localised Interference: Specific zones near maintenance hangars showed high bit-error rates affecting portable unit reception.
Armed with this data, the team worked with their radio vendor to fine-tune codec parameters and adjust Quality of Service (QoS) policies.
The Outcome: Follow-up tests confirmed a 25–30% improvement in MOS scores across the previously problematic zones. First responders reported consistent, intelligible audio, verified by data rather than anecdotes.
Conclusion
For critical operations, “good enough” communication isn’t good enough. By pivoting to an automated, metric-driven testing strategy with GL VQuad™, the airport ensured that its first responders can always be heard clearly when it matters most.
With continuous testing now in place, the communications team can detect degradations early, verify upgrades, and maintain the highest standard of safety across their mission-critical network.
