Voice services

VoLTE: the foundation of 5G voice services will unleash the power of voice

At the “Huawei VoLTE Pro Summit” held alongside the recent Mobile World Congress Shanghai, telecom professionals delivered a strong message calling on mobile industry players to adopt Voice over LTE (VoLTE) as quickly and as widely as they can, to reap the benefits of advances in mobile telecommunications technologies.

VoLTE has made great strides in helping mobile operators around the world migrate users from 2G and 3G to 4G and 5G, particularly due to the benefits of the technology in terms of superior voice quality and ability to compete. voice-data. As a result, carriers are able to phase out their 2G and 3G networks and reallocate frequencies and cell sites used by 2G and 3G for new mobile generations.

Globally, nearly 30% of LTE networks have launched a commercial VoLTE service. Regarding the role of VoLTE in voice traffic management, it varies from market to market. While more than 70% of voice minutes in China are routed via VoLTE, in some countries that number is less than 10%.

In his opening speech, Liu Kang, Chairman of SCC at Huawei, also pointed out the uneven development of VoLTE in the markets, but he believed that the main advantages of VoLTE could lead to wider adoption of VoLTE in a near future. These include its ability to transmit voice as data packets over the LTE data carrier, allowing operators to simplify network operations by disabling 2G and 3G. VoLTE’s voice-data concurrency capability enables more innovative and richer voice services, creating new value for operators. However, probably the most critical role VoLTE can play and its greatest opportunity in the coming years is its future role for 5G voice.

VoLTE is the basis of 5G voice service

Based on the IP Multimedia Subsystem (IMS) framework, VoLTE features and specifications were already locked in 2010. Despite its maturity and success in many markets, the adoption of VoLTE by LTE operations may still be significantly improved. According to data shared by Emanuel Kolta of GSMA Intelligence, who also spoke at the VoLTE Pro Summit, only 219 VoLTE networks had been activated as of February 2021. This represents 28% of a total of 785 LTE networks worldwide.

VoLTE penetration is expected to accelerate in the near future, driven primarily by operators migrating from circuit-switched infrastructure (2G and 3G) to IP-centric networks (4G and 5G). This is essential for 5G operators. As 5G no longer supports Circuit Switched Fallback (CSFB) for voice, they rely on VoLTE to provide voice service to their customers. While 5G (NR) coverage is still limited and devices supporting Voice over NR are not widely available at mass market prices, VoLTE will become the backbone of voice service in 5G in the coming years.

The other benefits of VoLTE will also make the technology more attractive to operators, including high quality voice as VoLTE uses a wider frequency range, especially with the adoption of the Enhanced Voice Services (EVS) codec. VoLTE call set-up time is reduced by two-thirds of conventional calls on circuit switches, providing users with a nearly delay-free experience. The voice and data concurrency capability of VoLTE enables a richer multimedia communication experience. Last but not least, VoLTE offers superior power and network efficiency compared to voice traffic over 2G and 3G networks.

With the benefits of VoLTE, especially with the demand related to the rapid expansion of 5G networks around the world, the penetration of VoLTE is expected to accelerate. Emanuel Kolta predicts there will be 400 commercial VoLTE networks worldwide by 2025, reaching 50% penetration among LTE operators. Meanwhile, the speed of 2G and 3G sunset is also expected to pick up the pace. Kolta predicts that a total of 94 2G networks and 54 3G networks will be shut down by 2025.

However, a number of building blocks need to be in place before the full potential of VoLTE can be unleashed. These include optimizing LTE coverage, extending roaming agreements to cover VoLTE, and developing and maturing new VoLTE-based services to make the technology more commercially attractive to operators.

LTE network coverage and voice innovations

Operators must continue their investments to ensure good LTE coverage, including indoor coverage. Otherwise, either voice traffic will continue to be routed through circuit-switched networks, delaying the refarming of spectrum used by 2G and 3G networks, or, if 2G and 3G networks are shut down prematurely, LTE coverage will be less optimally create new dead zones.

Telecom Argentina, which plans to terminate its 2G network in 2022, has found an ideal solution in VoLTE. Network Planning Manager Carlos Bardon shared with the audience the steps taken by the operator to get the most out of VoLTE. By deploying dual-band 4T4R RRUs (remote radio units) on the low bands (700MHz and 850MHz), the operator aims to build a ubiquitous coverage layer of the network, which will be the main voice carrier. Super Blade sites with an all-in-one configuration (2/3/4/5G) reduced opex by 43% and time to market by 52%. Regarding the improvement of user experience through network modernization, Bardon shared with the audience some key performance indicators, for example on 700 MHz, the capacity of 4T4R cells increased by 41%, while downlink speed improved by +123%. Bardon believes VoLTE is the best voice solution that can help the operator maximize their spectrum values. According to data shared by Bardon, measured by the number of voice users served by each 5 MHz spectrum, VoLTE is 2.2 times more efficient than 3G and 3.4 times more efficient than 2G.

Operators should also upgrade their roaming agreements with each other to include VoLTE, as most permanent agreements do not. South Korea’s KT and China Mobile entered into the world’s first VoLTE roaming agreement as early as 2014. However, more operators need to join the camp to provide VoLTE users with a similar and even better experience than what they are using now. on the networks.

In addition to ensuring customers can make voice calls without 2G or 3G networks to fall back on, on the home network and on the road, VoLTE also has much more to offer carriers and their partners to deliver new value. , relying on technological advantages . New opportunities are opened up by new audio technologies, for example, Immersive Voice and Audio Service (IVAS) which is an extension of the EVS codec. According to Markus Maltrus, Standard Expert at 3GPP, IVAS will enable full spatial conversation and full VR/XR experience. Maltrus estimated that the finalized standardization of IVAS will be included in 3GPP Release 17, scheduled for 2022.

This does not mean that the industry should wait for standardization to be ready before rolling out new services. In fact, many experiments and trials have been carried out by operators in different markets to test both the viability of new technologies and their business and user experience implications. China Mobile, the operator with by far the largest VoLTE users in the world, is one of the most active. According to Zhang Hao, deputy director of network and computer technology research at China Mobile Research Institute, 75% of China Mobile’s voice traffic goes through the VoLTE network and more than 100 million 5G subscribers use VoLTE for voice service. .

In addition to continuing to grow the number of users, China Mobile is clearly considering new services it can provide using VoLTE to create more value.

The operator has shared with the public a roadmap of new 5G services it plans to roll out while harnessing the technological capabilities and potential of VoLTE and, in the future, 5G New Calling. China Mobile is already testing the interactive call center menu, relying on VoLTE. In the near future, the operator plans to test HD immersive interactive calls using 5G New Calling. In the longer term, it provides for more intensive data communication and interaction in addition to call sessions.

Source: China Mobile Research Institute, February 2021

One core for all calls

To help carriers overcome the challenges they face when migrating circuit-switch-based voice calls to VoLTE, and to open up new business opportunities for mobile carriers, Huawei introduced its Single Voice Core (SVC) to handle all voice traffic passing through all active mobiles. generations (2G to 5G) as well as voice calls passing through the fixed network, a so-called 5-in-1 solution. This will not only simplify network operation and maintenance and optimize costs, but also provide an improved user experience.

Huawei hopes to lead the industry into a “VoLTE Pro” era, which will make VoLTE the basis for 5G voice calls with a richer and more innovative experience, help optimize LTE coverage, and provide IMS-based service over 2G networks. and 3G.

According to Vincent Zhao, President of CS & IMS Domain at Huawei, the company expects to see VoLTE penetration among LTE carriers, with the help of VoLTE Pro, increase from less than 30% now to 60% in the world over the next five years.

This content is sponsored by Huawei.

Huawei Technologies Co.Ltd