VoNR is the way voice calls operate on the most advanced 5G mobile networks. Unlike current solutions, which still rely on the 4G network to complete a call, VoNR uses only 5G infrastructure, enabling faster, more stable, and more efficient connections.
This allows users to enjoy high‑quality calls while browsing at full 5G speed, with no interruptions or technology switches happening in the background. VoNR is therefore a key step toward a fully 5G mobile experience.
The Market Milestone: MasOrange Spain
In September 2025, MasOrange became the first operator to commercially launch premium voice calls over 5G in Spain. This milestone marks a significant step forward in the evolution of mobile services in the country. With this new capability, calls become clearer, stronger, and more stable, even in areas with high concentrations of people, such as city centers, stadiums, or large events
Technical Description
With VoNR, IP based dedicated voice bearers are set up between UEs and the IP multimedia subsystem (IMS) on the NR network, enabling NR UEs to directly perform voice services on the NR network.
VoNR: Key Advances and the Differentiating Value of 3dB consult
Background and reasons for the roll-out of VoNR
The deployment of VoNR in 5G SA networks requires a rigorous validation and monitoring process to ensure that voice-over-NR services achieve performance equivalent to or better than that of VoLTE. To this end, it is essential to verify the correct establishment of IMS bearers, prevent degradation in audio quality, and optimize mobility behavior between NR and LTE when EPS fallback is required.
The most significant challenges include ensuring service stability, maintaining consistent call setup times, preserving continuity in mobility scenarios, and mitigating handover failures or unexpected behavior during the initial activation phases.
Technical intervention by 3dB consult
Behind this launch was a team that understood that innovation isn’t just about knowing metrics; it’s about connecting data, decisions, and people.
That’s where 3dB consult came in, supporting the entire process in a complex multi-vendor environment:
Technical Adjustments and Kpi Analysis
- Implementation of key parameters related to mobility (NR ↔ LTE), timers, DRX, ROHC, uplink MCS, and handover policies, with the aim of improving service stability and ensuring call continuity.
- Detailed KPI analysis under low‑volume VoNR‑capable UE conditions, identifying behavioral patterns and
adjusting the network to improve consistency and predictability.
Activation of Advanced Features
- Configuration of mechanisms such as Service‑Adaptive DRX, Link Adaptation, Priority Scheduling, UE Grouping, and VoNR‑specific mobility, ensuring differentiated handling for voice flows.
- Adjustment of thresholds and IRAT HO criteria to prevent call blocking or interruptions during VoNR ↔ VoLTE transitions, particularly in consecutive calls or coverage‑edge scenarios.
During the initial tests, something unexpected surfaced: in certain coverage‑edge areas, the phone would briefly lose its voice bearer for just 300–500 ms during the shift from 5G to 4G. It was a tiny interruption, but a clear sign that something deeper was happening.
After digging into traces and mobility KPIs, the cause was discovered, the A2 threshold was triggering the handover too early. An adjustment fixed the issue instantly, proving how crucial it is to validate mobility behavior under real‑world conditions (drive test/traces).
Results and Considerations
The rollout of VoNR didn’t just introduce a new voice technology, it proved that 5G could finally deliver the kind of experience users had been promised. From the very first tests, the results were clear: voice quality remained consistently high, matching VoLTE’s performance without any perceptible loss. MOS values were stable, confirming that IMS traffic running fully over NR delivered the same clarity users were accustomed to.
Call Setup Time told a similar story. VoNR calls connected just as fast as VoLTE, and in scenarios where the network relied on EPS Fallback, call setup was even 1–1.5 seconds quicker, a difference small on paper but very noticeable in everyday use.
Perhaps the most striking result was robustness. The network achieved a 0% Drop Call Rate, outperforming even mature VoLTE deployments. As advanced features were activated and mobility, DRX, and UE Grouping were fine‑tuned, the KPIs settled into a stable, predictable pattern. And once thresholds were recalibrated, IRAT handover issues disappeared entirely, allowing VoNR ↔ VoLTE transitions to happen smoothly and without disruption.
What this experience made evident is that launching VoNR isn’t about flipping a switch. It’s about ensuring that every call remains clear, stable, and reliable, even under challenging conditions. Voice services carry a uniquely human responsibility, when a call drops, it’s not just a metric; it’s a conversation interrupted, a moment lost. That’s why every technical decision must be guided by responsible, user‑centered innovation.
The work behind the deployment also highlighted something crucial: true technical leadership goes beyond understanding parameters. It requires reading what the network is trying to say through its data, making the right trade‑offs at the right time, coordinating teams, and anticipating behaviors in a complex 5G SA environment.
Bringing all these pieces together is what transforms VoNR from a promising feature into a mature, operational‑grade service.