Recently, China Telecom and Huawei jointly completed the world's first voice and video call on a 5G SA network in China Telecom Intelligent Network and Terminal Research Institute.

In this test, Huawei 5G SA mobile phones and network devices are used from end to end, including 5G smartphones with HiSilicon Balong 5000 chips, wireless base stations, 5G core networks and IMS device. The network architecture and service procedures are the same as those of a commercial network. The phone number can be directly dialed and answered. The QoS of the call is guaranteed, and user experience is better than that when a 5G CPE or VoIP soft client is used. This achievement marks the next phase of end-to-end 5G commercial applications by China Telecom.

In 5G voice services, UEs use VoNR within 5G coverage areas and use VoLTE in 4G coverage areas. EPS fallback allows 5G UEs to camp on 5G NR but provides voice services on 4G networks. When a UE initiates a voice call, it hands over to the 4G network to use voice services through VoLTE. EPS fallback provides a transition solution for voice services during early deployments of 5G, prior to native support of VoNR as the industry matures. This time, China Telecom has tested EPS fallback. The test results show that voice calls as a basic service in 5G communications have become mature for commercial use.

Figure 1: The UE accesses the 5G network and registers with the IMS.

Figure 2: During the call, the UE falls back to the 4G network and connects to the HD voice call.

5G will support new services such as ultra-large bandwidth services, ultra-low latency services, and massive connection services. However, voice services are still indispensable. Since this year, China Telecom has made rapid progress in 5G commercial tests and made significant achievements in commercial use of 5G, to lay foundations for commercializing 5G and delivering an ultimate service experience to subscribers.

— Jay Liu, Senior Marketing Manager, Cloud Core Product Line, Huawei Technologies Co.

This content is sponsored by Huawei Technologies.