Simplifying Voice Quality Testing with GL’s VMobile™
Customer satisfaction in mobile networks hinges on call clarity. This case study details how a national operator replaced bulky drive-test kits with the compact GL VMobile™ to standardize POLQA and MOS testing across 4G and 5G networks.
Background
A national mobile operator was under increasing pressure to maintain high voice quality as it expanded its 4G and 5G coverage footprint. Customer satisfaction surveys showed that even minor degradation in call clarity or connection reliability directly impacted churn rates — particularly among enterprise and business users.
Historically, the carrier relied on drive testing teams equipped with bulky test kits and multiple devices to measure call performance and audio quality across the network. Each team used different phone models and configurations, making it difficult to compare results between regions or over time.
To address these challenges, the operator adopted GL Communications’ VMobile™ — a compact, portable platform designed for field-based voice and data quality testing using real mobile devices.
The Challenge
Maintaining consistent voice quality across a nationwide network requires ongoing measurement of key user experience metrics, including:
- Mean Opinion Score (MOS) and POLQA audio quality ratings.
- Call setup time and call completion rates.
- Speech delay, jitter, and packet loss in VoLTE and VoNR sessions.
Traditional methods were time-consuming and inconsistent. Field engineers had to carry multiple phones and record calls manually, synchronise audio samples after tests for offline analysis, and use separate tools for 2G/3G, 4G, and 5G voice measurement.
The operator needed a lightweight, standardised test solution that could capture real voice quality data under actual network conditions — without complex setup or lab-style equipment.
The Solution: GL VMobile™ for Field Voice Quality Testing
The engineering team equipped its regional field technicians with GL’s VMobile™ platforms — handheld, battery-powered devices capable of connecting to mobile phones, Bluetooth headsets, or radio handsets to emulate real user scenarios.
Each VMobile unit connects to a companion device under test (such as a smartphone running a SIM from the operator’s network) and records both the transmitted and received audio paths during a live call. These samples are automatically time-aligned and analysed using GL’s VQT (Voice Quality Testing) software to calculate objective voice quality metrics like POLQA MOS.
Technicians can conduct multiple simultaneous tests — including mobile-to-mobile, mobile-to-fixed, or mobile-to-VoIP calls — and automatically upload results to a central server for reporting and benchmarking.
The VMobile platform supports all major voice technologies, including 2G, 3G, VoLTE, and 5G VoNR, allowing the carrier to use one consistent tool across all network generations.
The Results
After deploying VMobile nationwide, the carrier achieved several operational improvements:
- Simplified field workflows — engineers needed only one compact device instead of multiple test kits.
- Faster test cycles — complete voice quality tests took minutes rather than hours.
- Consistent, repeatable results across regions, enabling direct comparison of MOS and latency data.
- Centralised reporting integrated with GL’s VQT software, giving management real-time insight into call quality trends.
The system also made it easy to identify problem areas — such as cell sites with degraded codec performance or increased jitter on VoLTE bearers — allowing proactive optimisation before customers noticed any issues.
Conclusion
By adopting GL’s VMobile™, the carrier transformed its voice quality assurance process from a fragmented, manual task into a streamlined, standardised, and data-driven operation.
Field engineers can now verify real-world call performance using a single, portable device, while central teams benefit from consistent metrics and automated reporting.
The result is a faster, simpler, and more reliable way to ensure that voice remains crystal clear across an increasingly complex multi-technology mobile network — helping the carrier maintain both quality and customer confidence.
