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VoLTE: The sound of voice, driving the future of communication

VoLTE: The sound of voice, driving the future of communication

Voice over LTE (VoLTE)

Discover how VoLTE revolutionizes mobile voice communication, supports the transition from 2G and 3G networks to modern IP-based technologies, and unlocks advanced services for communication service providers (CSPs) and users alike. With VoLTE serving as a foundation for 5G Voice and beyond, it is a cornerstone of future mobile communication.

From circuits to packets: The VoLTE story

VoLTE, short for "Voice over LTE," is a technology that enables voice calls over LTE networks, commonly known as 4G networks. Unlike older technologies that require separate infrastructure for voice and data, VoLTE integrates voice communication directly into the 4G network, enabling both standard phone calls, advanced services beyond traditional voice communication, and emergency services like calling the police on the same efficient system.

By replacing the circuit-switched systems of 2G and 3G with an all-IP (Internet Protocol) approach, VoLTE delivers faster call setup times, enhanced call quality with EVS (Enhanced Voice Services), seamless WiFi calling, and the flexibility to switch seamlessly between voice and video calls. Future codecs like IVAS (Immersive Voice and Audio Services) further improve clarity and enable a new standard of high-definition communication. This makes it the gold standard for voice communication on modern mobile networks.

Find inspiration how VoLTE provides a greater user experience | Video | 2 min.

How does VoLTE work?

VoLTE transforms traditional voice communication by transmitting voice data as packets, much like how internet data flows. This IP-based architecture optimizes network resource usage, allowing CSPs to provide high-quality voice services alongside data on the same LTE infrastructure.

VoLTE stands out with advanced codecs that offer superior voice clarity, creating a more natural-sounding call experience. It also ensures consistency in features like call waiting, caller ID, and voicemail, even while roaming internationally. This seamless integration of voice and data communication makes VoLTE an essential platform for reliable, feature-rich voice services.

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How VoLTE relates to VoIP

VoLTE and VoIP (Voice over Internet Protocol) share a foundation in IP-based technology but are designed for distinct environments. VoLTE is tailored for mobile networks, utilizing LTE (4G) infrastructure to deliver high-quality, reliable voice calls integrated with mobile features like emergency calls and seamless roaming. It prioritizes voice traffic on the network, ensuring consistent quality even during peak usage.

In contrast, VoIP operates over any internet-based network, such as Wi-Fi or broadband, and is commonly used in popular video conferencing and communication applications. While VoIP offers flexibility across various devices, its reliability and call quality depend on the stability of the internet connection. Unlike VoLTE, VoIP lacks the carrier-grade features and mobile integration that make VoLTE a seamless upgrade for traditional telephony. Additionally, VoIP requires communication applications to be installed on devices, whereas VoLTE is natively integrated into mobile devices like smartphones, ensuring a more seamless user experience despite VoIP's flexibility across various devices.

Feature VoLTE VoIP
Connectivity Mobile devices with LTE/WiFi compatibility Desktop/mobile devices, VoIP phones
Network type Requires 4G LTE network, and works seamlessly with 5G and WiFi Works over broadband/Wi-Fi internet
Integration Built into the phone’s dialer Requires a third-party app
Reliability More reliable (uses prioritized mobile networks) Depends on Wi-Fi/data quality
Emergency calls Natively supported and prioritized by the mobile network The ability to make emergency calls with VoIP depends on the service provider
Call quality Prioritizes voice data with advanced codecs like EVS, supports WiFi calling Possible jitter/latency from internet connection
Costs Included in smartphone plans Unlimited domestic calling included in monthly VoIP plans

Key benefits for CSPs

While VoLTE brings noticeable improvements for end users, it was primarily implemented to address challenges faced by communication service providers. By transitioning to IP-based technology, CSPs have been able to optimize their networks and offer more advanced services. Key benefits include:

Efficient use of network resources

VoLTE replaces the less efficient circuit-switched technology used in 2G and 3G with a packet-based IP system. This transition allows CSPs to maximize the utilization of their network resources, enabling them to handle voice and data more effectively on the same infrastructure.

Expanded service capabilities

Built on the IMS framework, VoLTE enables CSPs to deliver innovative services such as WiFi calling, video calling (ViLTE), and seamless multi-device integration. These advanced offerings enhance the customer experience and open opportunities for CSPs to differentiate their services with value-added features.

Improved roaming experience

Unlike 3G roaming, which often limited the access to home-country features, VoLTE allows users to maintain their regular services – including call waiting, voicemail, and caller ID – while roaming internationally. This ensures a seamless experience for customers traveling abroad, enhancing their satisfaction and loyalty.

Enhanced call features

VoLTE also supports specialized capabilities like branded enterprise communication solutions and robust fraud detection mechanisms. These features empower CSPs to go beyond traditional voice services, offering secure and tailored communication solutions that meet the demands of businesses and consumers alike.

Technical and infrastructure requirements for VoLTE deployment

The deployment of VoLTE requires a modern and robust network infrastructure to deliver high-quality, reliable voice services. CSPs must ensure that their networks have the necessary components and configurations to support VoLTE effectively.

IMS: The Core of VoLTE

At the heart of VoLTE lies the IMS, a critical architectural component for enabling multimedia services like voice over IP networks. IMS handles session management, call control, and routing, making it indispensable for VoLTE deployment. The shift from circuit-switched to IP-based networks was driven by the efficiency of IP technology and its ability to support richer communication services. Without an IMS system, VoLTE cannot function.

Essential network features and optimization

VoLTE deployment also requires specific features in both the radio access network (RAN) and the packet core network to ensure compatibility with the IMS. Additionally, precise radio network tuning is essential to optimize call quality and minimize issues like dropped calls or poor audio performance. This tuning process aligns the network to the unique requirements of handling voice traffic over LTE, ensuring a seamless user experience.

Deployment models and considerations

Deployment models and considerations

VoLTE deployment requires careful planning and consideration of infrastructure, technology choices, and long-term scalability. Ericsson currently deploys VoLTE on its proprietary cloud platforms, including Ericsson Cloud Native Infrastructure (CNIS), while supporting third-party platforms like VMware and Red Hat OpenStack. This flexible approach allows CSPs to leverage existing infrastructure and expertise. Additionally, Ericsson is advancing deployment options by exploring as-a-service models, and flexible consumption.

CSPs must evaluate key factors when deploying VoLTE. A robust IMS and optimized radio and packet core networks are critical for supporting reliable voice traffic. Comprehensive 4G coverage and spectrum availability are essential for delivering quality services, while VoLTE-compatible devices and roaming agreements play vital roles in adoption and seamless international connectivity. Future-proofing deployments is also crucial, ensuring compatibility with 5G core networks and emerging technologies. As CSPs transition to 5G voice, leveraging advanced IMS features and tuning networks for new capabilities will be essential for maintaining high-quality service and a smooth evolution.

Advanced services enabled by VoLTE and IMS

Advanced services enabled by VoLTE and IMS

VoLTE unlocks various advanced services beyond traditional voice communication. These capabilities enhance both the user experience and the functionality available to CSPs.

Robust protections against fraud and nuisance calls are critical for building trust in VoLTE and ensuring safe and reliable communication.

VoLTE supports comprehensive emergency communication services, including:

  • Real-time Text communication
  • SMS and video capabilities
  • Enhanced location sharing for first responders

The ability to seamlessly integrate multiple devices, such as smartphones and smartwatches, is increasingly important in the connected, multi-device world.

VoLTE ensures clear, high-definition voice communication for devices like smart home hubs, connected vehicles, and wearables. This enables reliable and efficient voice interactions, enhancing functionality in both consumer and industrial applications.

Innovations like Reduced Capability (RedCap) expand VoLTE's reach to low-cost devices, broadening its accessibility. Additionally, VoLTE plays a critical role in mission-critical communications, providing secure and reliable connectivity for public safety, utilities, and other essential industries.

Read more about RedCap

Additional use cases for VoLTE

Mission-critical communications

VoLTE supports highly secure, reliable, and resilient communication for mission-critical applications. These include connectivity for government and public safety agencies, utilities, and rail transport industries. VoLTE’s capabilities ensure seamless voice, data, and video communication for first responders and other critical operations, complementing or evolving existing Land Mobile Radio (LMR) systems.

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Remote monitoring services

In industrial IoT settings, VoLTE supports voice communication between field workers and central control rooms. This capability enhances coordination, improves safety, and ensures quicker responses during operations.

The Ericsson VoLTE offering

Ericsson’s VoLTE capable solutions encompass all of the communication core and radio network components, and professional deployment and tuning services necessary to provide high-quality and innovative voice use cases. The solutions enable consumer voice services for smartphones, smart watches and smart speakers, but also build a foundation for high-quality mobile voice and communication services and collaboration services for businesses, enterprises and industries.

The IMS solutions can be delivered with short time-to-market as pre-integrated and verified solutions and can improve total cost of ownership and reduce network operation and maintenance costs.

The Ericsson VoLTE offering

Why choose Ericsson?

Ericsson stands out in the VoLTE landscape through:

  • Proven network quality, many of our customers consistently ranked as number one by Umlaut
  • Advanced IMS API capabilities, enabling seamless integration into CSPs’ ecosystems
  • Robust Call Qualification (a spam and fraud protection service) and service exposure technologies
  • Ability to provide enterprise-grade solutions, such as branded calls that display an enterprise’s name or logo to called mobile users, enhancing brand recognition and increasing call completion rates.

Choose Ericsson’s VoLTE solutions if you want to:

  • Innovate quickly: be first to market with voice services innovations through global device eco-system partnerships.
  • Easily broaden your offerings: utilize a unique solution to expand your consumer service for businesses and enterprises.
  • Gain agility: deploy VoLTE in weeks with industrialized cloud-based solutions.
  • Grow your market: extend with new 5G communication services. Our VoLTE capabilities also ensure support for seamless emergency services and future-ready technology.
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The future of VoLTE

VoLTE has played a pivotal role in the global success of 4G LTE, enabling CSPs to deliver superior voice quality, lower operational costs, and better user experiences through a simplified, packet-based network architecture. As IMS technology evolves, VoLTE will continue as a critical enabler for the next generation of communication services, including 6G. The evolution to 5G introduces new architectures, such as Non-Standalone (NSA) and Standalone (SA) architectures, and technologies like Voice over New Radio (VoNR). While VoLTE will coexist with these 5G solutions for years to come, it provides the reliability and flexibility needed during this phased deployment. CSPs can build on their VoLTE experience, reusing much of the existing IMS infrastructure to ensure seamless service continuity. As 5G networks expand to enable transformative applications like VR/AR and Industrial IoT, voice services – including VoLTE and VoNR – will remain vital for ensuring quality, innovation, and customer satisfaction in the next era of mobile communication.

Read more about 5G voice

VoLTE subscriptions

VoLTE subscriptions are projected to reach 8.2 billion by the end of 2030. Explore this and other insights in the Ericsson Mobility Visualizer.

Looking ahead: VoLTE as the foundation for 5G voice

VoLTE and 5G voice are built on the same IMS foundation, enabling CSPs to seamlessly upgrade to 5G voice while maintaining their existing infrastructure. With some VoNR networks already operational, VoLTE ensures a smooth transition, providing fallback options (EPS Fallback) in areas where 5G coverage is limited. This coexistence ensures reliable voice services as 5G networks expand and supports devices that lack 5G capabilities. Looking ahead, 6G networks are likely to build on the principles of VoLTE technology, making it a future-proof investment for CSPs.

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VoLTE                                              

High-quality voice calls over 4G LTE networks, leveraging IP-based technology for improved efficiency, clarity, and reliability.                                                                                                                                                                                                                                                  

EPS Fallback                        

Seamless switch from 5G to VoLTE in areas with limited 5G coverage, ensuring uninterrupted voice services. Single Radio Voice Call Continuity (SRVCC) enables seamless handover from 4G to existing GSM and WCDMA networks when necessary.

VoNR (Voice over New Radio)

Native 5G voice technology delivering enhanced call quality, consistent data speeds, and advanced features on fully deployed 5G networks.                                                                                                                                                                          

The role of cloud-based VoLTE in the 5G voice evolution

Cloud-based VoLTE is key to the transition to 5G voice, offering scalability, cost-efficiency, and faster deployment through virtualized infrastructure. By eliminating reliance on physical hardware, CSPs can reduce costs, simplify operations, and respond more quickly to market demands. This shift aligns with industry trends toward NFV, enabling more agile and efficient networks.

As 5G networks evolve, cloud-based VoLTE integrates seamlessly with the 5G core. This convergence supports advanced features like network slicing and edge computing, enabling low-latency voice services and tailored solutions for specific use cases. The adoption of cloud-based VoLTE positions CSPs to deliver next-generation voice services while ensuring a smooth transition to 5G.

Hardware independence

Cloud-based VoLTE eliminates the reliance on proprietary hardware by virtualizing network functions, enabling deployment on a wide range of commercial off-the-shelf (COTS) hardware. This independence allows CSPs to reduce costs associated with specialized equipment and simplifies the supply chain. Additionally, it provides the flexibility to deploy VoLTE on diverse cloud environments, aligning with each CSP’s strategic goals.

Automation

Automation is a core advantage of cloud-based VoLTE, leveraging centralized orchestration tools to streamline network operations. Tasks such as provisioning, scaling, and updating network resources can be automated, reducing the need for manual intervention and lowering operational complexity. This not only accelerates service deployment but also minimizes human error, ensuring a more reliable and efficient network.

Business agility

The agility provided by cloud-based VoLTE empowers CSPs to respond quickly to market demands and evolving customer needs. With the ability to scale network resources dynamically and introduce new services rapidly, CSPs can stay ahead of competitors while meeting the expectations of users. This flexibility is especially valuable in adapting to fluctuating traffic patterns and exploring new revenue streams through innovative services like tailored voice solutions or differentiated network slices.

Let’s talk voice and RedCap


Explore how mobile voice services in 4G and 5G, including advancements like RedCap for IoT and low-cost devices, can bring value to users while opening new revenue streams for service providers. Discover how these innovations enhance connectivity and expand the possibilities for voice communication in emerging applications.

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