ZTE Successfully Completes Real-Time Voice Verification for LEO NR-NTN Based on 3GPP Standards

　　ICC Information News -- Recently, ZTE, in collaboration with the China Mobile Research Institute and MediaTek, achieved a new technological breakthrough by successfully completing real-time voice lab verification for direct satellite-to-phone low earth orbit (LEO) NR-NTN (New Radio Non-Terrestrial Network) based on 3GPP standards. The actual test showed that the satellite phone call setup delay was around 1 second, with one-way voice latency over the air interface within 50ms. Additionally, it supports mobile broadband services via satellite. Under transparent forwarding mode in a lab environment, simulating dynamic LEO 600km NTN channels using a channel emulator, the measured downlink peak rate per beam reached 18 Mbps. This successful verification marks further maturity of the 5G NR-NTN industry and accelerates the pace of commercial deployment. It also signifies a new milestone for NR-NTN technology in satellite communications, laying a solid foundation for future integrated terrestrial-space communication networks.

　　The testing was led by China Mobile, utilizing ZTE's 5G-A NTN integrated space-ground base station equipment and core network optimized for NR-NTN IMS voice on the network side. On the terminal side, MediaTek’s Dimensity mobile chip platform was used. The tests were conducted in a lab setting where Keysight Technologies' satellite channel emulator connected the base station and terminal. During the tests, ZTE, China Mobile, and MediaTek jointly overcame challenges posed by high-speed mobile satellite channels, achieving precise time-frequency offset compensation and synchronization tracking using advanced LEO satellite tracking and trajectory prediction technologies. The results demonstrated performance close to terrestrial mobile communication time-frequency synchronization. The tests confirmed that under LEO satellite scenarios, phones can support VoNR real-time voice communication, enabling smooth voice calls between NR-NTN users as well as between NR-NTN users and ground-based mobile communication network VoLTE/VoNR commercial terminals.

　　NR-NTN is one of the key technologies in the 5G-A and 6G phases defined by 3GPP, providing ubiquitous network coverage by integrating satellite communication networks with terrestrial 5G networks, thus realizing seamless access across various environments including air, space, land, and sea. The success of this verification not only showcases the application potential of NR-NTN technology in satellite communications but also highlights ZTE’s technical strength and leading position in the exploration of integrated terrestrial-space networks.