What is 5G VoNR technology?

　　With the continuous expansion of 5G, VoNR (Voice over New Radio) has gradually become a key technology to shape the future of voice services in the 5G era. Let's first review the history of mobile voice technology to analyze the evolution, definition and significance of VoNR.

　　A brief history of mobile voice evolution

　　Mobile voice services have undergone major changes between generations:

　　2G/3G era: Reliance on circuit switching (CS) technology, which reserves exclusive network resources for each call. This method is inefficient, resource-intensive, and slow to establish calls (6-8 seconds).

　　4G LTE era: Shift to all-IP (packet switching, PS) networks, introducing two voice solutions:

　　CSFB (Circuit Switched Fallback): The phone falls back to the 2G/3G network when making a voice call, and then returns to the 4G network after the call - cumbersome and slow.

　　VoLTE (Voice over LTE): IP-based voice is implemented directly on LTE through IMS (IP Multimedia Subsystem), which revolutionizes voice services with faster setup speed (2-3 seconds), wider bandwidth (up to 50Hz-7000Hz through AMR-WB coding) and clearer sound quality (MOS value is about 4.1).

　　5G Voice Solution: From Fallback to VoNR

　　5G networks (NSA and SA architectures) are built on the IP foundation of 4G, but provide more advanced voice options:

　　1. VoLTE in 5G NSA networks

　　In non-standalone (NSA) mode, 5G NR acts as a data capacity extension of the 4G core network (EPC). Voice services still rely on 4G's VoLTE, without changing the existing IMS infrastructure. This ensures continuity but limits the full potential of 5G in voice.

　　2. EPS Fallback in 5G SA Networks

　　In standalone (SA) mode (5G Core + NR), early deployments used EPS fallback: when a voice call is initiated, the device switches to 4G VoLTE and then returns to 5G after the call. Although better than 2G/3G fallback, there are some disadvantages:

　　Longer call establishment time due to network switching.

　　Data speeds temporarily drop during calls.

　　Voice is briefly interrupted during fallback, affecting user experience.

　　3. VoNR: The Ultimate 5G Voice Solution

　　Voice over New Radio (VoNR) is an end-to-end 5G voice service natively carried on 5G NR, 5G Core (5GC), and IMS. Although sometimes referred to as Vo5G (Voice over 5GS) for accuracy (because 5GS includes NR and 5GC), "VoNR" is the more commonly used term.

　　In SA mode, VoNR does not need to fall back to 4G networks, enabling:

　　Faster call setup: 1.5-2 seconds (faster than VoLTE's 2-3 seconds).

　　Concurrent high-speed data: Users can make calls while enjoying 5G's ultra-high-speed Internet (for example, play 4K video during a call).

　　Seamless switching: Supports smooth switching to VoLTE when leaving 5G coverage, and ensures call continuity through Inter-RAT switching (similar to 4G's SRVCC).

　　Main benefits of VoNR

　　For users

　　Excellent voice quality: MOS value reaches 4.6, and the sound is clearer and more natural (extending VoLTE's broadband capabilities).

　　Low latency: Near-instant call setup and minimal latency, critical for real-time communications.

　　Enhanced multimedia support: Lays the foundation for immersive experiences, such as AR/VR calls and multi-sensory (voice, video, touch) interactions.

　　Operator Advantages

　　Network Efficiency: Reduces reliance on legacy 2G/3G networks, reduces maintenance costs, and frees up low-frequency spectrum for 5G.

　　Enabler of New 5G Services: Supports high-bandwidth applications such as holographic calls and IoT-driven voice interactions (e.g., smart city devices).

　　Revenue-generating Potential: Supplements 5G data packages with high-quality voice while opening the door to enterprise solutions (e.g., industrial IoT communications).

　　The Future of VoNR

　　VoNR is more than just an upgrade for voice calls; it is the cornerstone for 5G to realize its full potential. As 5G SA network coverage expands, VoNR will replace fallback solutions, providing seamless, high-quality voice while maintaining 5G's signature speeds and low latency.

　　For users, this means faster, clearer voice calls that incorporate next-generation multimedia technologies. For operators, this is an important step in retiring outdated infrastructure and opening up new revenue streams driven by 5G.

　　In short, VoNR ensures that 5G delivers on its promise—not just to be a data engine, but also a transformative platform for all communications needs.