PAGE CONTENTS
Objectives
The research and development (R&D) programme aims to enable voice-call functionality over Non-Terrestrial Networks (NTN) using NB-loT waveforms.
The programme addresses the critical technological gap in current satellite communication systems by extending the capabilities of the NB-loT protocol stack to support Voice across various satellite constellations (GEO, MEO, LEO).
Building on 3GPP Release 17 specifications and targeting TRL 4, the activity will develop new protocol stack functions in both UE and gNB, evaluate state-of-the-art and ML-based voice codecs, and validate voice services via satellite across GEO, MEO and LEO constellations.
There are three factors influencing the project:
- NB-IoT NTN Protocol Stack
- Codec
- Signaling architecture/protocols and associated overheads
The activity shall select the most promising approach to support of voice over NB-IoT NTN and shall demonstrate its feasibility over a NB-IoT communication link via satellite to support different use cases and deployments:
- Develop new functions in the protocol stack in support of voice calls using the latest NTN NB-IoT waveform.
- Select the most promising voice encoder / decoder technology/approach
- Demonstrate its feasibility over a NB-IoT communication link via satellite and required network equipment evolutions
- The R&D scope includes a fully validated proof-of-concept for selected use cases.
Challenges
Determine the use cases for this technology, and the technical requirements to support each one. Determine which technology solutions will be capable of supporting specific use cases, and the limit conditions for different alternatives.
System Architecture
The system will be based on the 3GPP standard 5G network architecture for the data transport between the UE (user device) and the core network. Some protocol evolutions/additions to the architecture are potentially required to support voice call setup and voice data treatment.
Plan
The project has an initial investigative phase (WP1-3) to scope the use cases and associated technical requirements / solutions, planned to take 9 months. This is followed by a development phase (WP4-5) lasting six months to create an operational demonstration and test system for at least one relevant use case.
Finally, WP6 will evaluate the results and future evolution of the project.
Current Status
The project has started with the KOM on 17 December 2025, and the WP1 deliverable work is in progress.
