VoNR vs VoLTE : Key difference between Vo5G and VoLTE

Voice communication technology has rapidly evolved over the years, transitioning from traditional cellular calls to advanced IP-based systems. Two prominent technologies in this realm are Voice over 5G New Radio (VoNR or Vo5G) and Voice over LTE (VoLTE). While both enable high quality voice calls over mobile networks, they differ significantly in terms of infrastructure, features and applications. This article dives into the key difference between VoNR and VoLTE to help you better understand their role in modern communication.

Introduction: Voice is used as fundamental service in cellular mobile communication systems. 1G was analog communication network which offered circuit switched voice services. CS (Circuit Switched) based voice and PS (Packet Switched) based data services are used in 2G/3G networks. 4G offered IP based services for both voice and data. IMS is a standard which defines telephony services, voice, messaging and video over IP network. Both 4G LTE and 5G NR (New Radio) offer IMS based voice over IP.

VoLTE delivers HD voice, faster call setup times and improved battery life. VoNR (Voice over 5G New Radio) delivers high speed, high bandwidth IP network connectivity and multi-service applications. VoNR is equivalent to VoLTE.

Voice Over 5G NR,Voice over NR,VoNR,Vo5G

Voice calls in LTE network are serviced using various options which include CSFB (Circuit Switched Fall back), VoIP (Voice over IP), In CSFB option, voice is offloaded to 2G/3G network from main 4G LTE network. In VoIP, handsets and 4G network should be VoIP compliant otherwise OTT (over-the-top) apps are used. The final option for voice over LTE is VoLTE which used IMS entity and voice is carried as VoIP packets. SIP (Session Initiation Protocol) is the key protocol for IMS architecture. IMS services include basic and advance services viz. voice/video call, IM messaging, SMS/MMS, voice mail, self care, video conference, cloud address book, social network integration, breakout to PSTN etc.

Voice services in 5G NR network are served by adopting various options such as EPS Fall Back, Voice over eNB with 5G core (VoeLTE) and Voice over NR (VoNR).

Voice over 5G NR : VoNR

VoNR represents the cutting edge of 5G voice technology. Let us explore specifications and requirements of Voice over 5G network.

Specifications of VoNR :
• Network Technology: Operates over 5G New Radio (5G NR).
• Frequency Bands: Utilizes both Sub-6 GHz and mmWave spectrum.
• Latency: Ultra-low latency (<10ms for end to end).
• Bandwidth: Higher bandwidth due to 5G capabilities.
• Call Setup Time: Faster than VoLTE due to improved signaling.

Features of VoNR :
1. High Call Quality: Provides superior voice clarity with HD or Ultra-HD voice due to higher 5G spectrum availability.
2. Seamless Data and Voice Integration: Simultaneously handles high-speed data and voice calls without degrading performance.
3. Low Latency Applications: Supports real-time services like augmented reality (AR), virtual reality (VR), and remote operations.
4. Reliability: Operates efficiently in dense environments, such as urban areas or stadiums.
5. Future Ready: Fully compatible with 5G core networks, ensuring long-term usability.

Requirements of VoNR :
• A fully deployed 5G standalone (SA) core network.
• 5G-enabled devices with VoNR support.
• IMS (IP Multimedia Subsystem) architecture integrated into the 5G core.
• Adequate 5G spectrum availability (Sub-6 GHz and mmWave).

Voice over LTE : VoLTE

VoLTE is a mature, widely deployed solution for 4G networks. Let us explore specifications and requirements of Voice over LTE network.

Specifications of VoLTE :
• Network Technology: Operates on 4G LTE.
• Frequency Bands: Utilizes licensed LTE spectrum.
• Latency: Low latency (~20 to 40ms for end to end).
• Bandwidth: Limited by 4G capabilities.
• Call Setup Time: Faster than 3G, but slower compared to VoNR.

Features of VoLTE :
1. HD Voice Calls: Provides high quality voice communication over IP-based LTE networks.
2. Wide Deployment: Compatible with most 4G networks globally.
3. Video Calls: Supports seamless video calls with VoLTE-compatible devices.
4. Battery Efficiency: More power efficient than circuit-switched fallback (CSFB) in 4G.
5. Fallback Support: Compatible with 3G and 2G networks for voice services where LTE is unavailable.

Requirements of VoLTE :
• IMS (IP Multimedia Subsystem) integrated into the 4G core network.
• VoLTE capable devices.
• Network operators must support VoLTE on their LTE infrastructure.
• Sufficient LTE spectrum for reliable coverage.

Difference between VoNR and VoLTE

Following table mentions comparison between Vo5G and VoLTE with respect to various system parameters.

Aspect	VoNR (Voice over 5G NR)	VoLTE (Voice over LTE)
Network Technology	Operates on 5G New Radio (5G NR) technology.	Operates on 4G LTE networks.
Speed and Latency	Offers ultra-low latency and faster call setup.	Provides low latency but higher than VoNR.
Infrastructure	Requires a fully deployed 5G core network.	Works on 4G networks with an IP Multimedia Subsystem (IMS).
Call Quality	Enhanced call quality due to higher bandwidth.	High quality calls but limited by 4G spectrum.
Compatibility	Requires 5G enabled devices and networks.	Supported by most 4G devices and networks.
Data and Voice Handling	Simultaneously handles high speed data and voice calls on 5G.	Handles data and voice over LTE effectively.
Deployment	Still in early stages; requires extensive 5G rollouts.	Widely deployed and mature technology.
Applications	Ideal for applications requiring ultra low latency, like AR/VR calls.	Sufficient for standard voice and video calls.
Transition	Future proof solution for 5G networks.	Acts as a bridge from 3G to 4G, and now to 5G.
Role of Vo5G	Vo5G is often used interchangeably with VoNR, representing voice services over 5G networks.	Vo5G complements VoLTE in the transition to 5G.

Conclusion

Both VoNR and VoLTE represent milestones in the evolution of mobile voice communication, each catering to different network generations. While VoLTE has been a reliable solution for 4G networks, VoNR is set to revolutionize voice calls in the 5G era, offering enhanced speed, efficiency and integration with advanced technologies. Understanding these differences is crucial for grasping how the telecom industry is shaping the future of seamless connectivity.
➨Also refer advantages and disadvantages of Voice over LTE and Voice over 5G NR to understand differences between Vo5G and VoLTE.