NTN Satellite: Integrating Satellite Communication with Terrestrial Networks

The NTN (Non-Terrestrial Network) satellite specifications are designed to seamlessly integrate satellite communication with terrestrial mobile networks. This integration facilitates worldwide connectivity, particularly in areas lacking terrestrial coverage.

The 3GPP Release 17 specifications for Non-Terrestrial Networks (NTN) have been developed to integrate satellite communications into the broader mobile network ecosystem, enabling seamless global connectivity.

Here are the key specifications of NTN satellites:

• Orbit Types: NTN standards support both Low Earth Orbit (LEO) and Geostationary Earth Orbit (GEO) satellites. LEO satellites operate at altitudes above 600 km and move at approximately 8 km/s, while GEO satellites remain nearly stationary relative to the Earth’s surface.

• Architecture: There are two main architectures for NTN:

  1. Transparent Architecture: The satellite acts as a repeater, with base stations (gNodeB) on the ground performing most of the signal processing.
  2. Regenerative Architecture: The satellite incorporates parts of the base station, enabling on-board processing and inter-satellite links. This provides more flexibility and enhanced performance.

• Communication Links: The satellite connects to user equipment (UE) via service links and to the core network through feeder links, utilizing satellite ground stations or gateways.

• Beam Management: Satellites utilize individual beams, known as spot beams, to cover specific sub-areas. These beams can be fixed relative to the satellite or steered to remain fixed relative to the Earth. Steering reduces the need for frequent handovers as the satellite moves.

• Latency and Doppler Shift: The system compensates for large round-trip delays and Doppler shifts caused by the satellite’s movement. GEO satellites can have round-trip delays longer than 500 ms, while LEO satellites experience delays in the tens of milliseconds.

• Interoperability: The NTN standards ensure complete interoperability between satellite and terrestrial networks, allowing seamless connectivity for smartphones and IoT devices across both network types.

These specifications, part of the 3GPP Release 17 standards, represent significant progress in integrating satellite and mobile networks, opening up new possibilities for global connectivity.

Benefits and Advantages of NTN Satellites

Here are some of the key benefits and advantages of using NTN satellites:

• Extended Coverage: NTN satellites provide connectivity in remote, rural, and underserved areas where terrestrial infrastructure is either unavailable or impractical to deploy.
• Enhanced Resilience: Combining terrestrial and satellite networks enhances the overall resilience of communication systems.
• Global IoT Connectivity: NTN satellites enable global coverage for Internet of Things (IoT) applications, allowing IoT devices to operate seamlessly across different regions without relying on local terrestrial networks.
• Seamless Handovers: NTN systems support seamless handovers between terrestrial and satellite networks, providing uninterrupted connectivity for users on the move.
• Cost Efficiencies: The integration of NTN into mobile networks can lead to cost efficiencies and economies of scale by leveraging existing satellite infrastructure.

Conclusion

These benefits highlight the transformative potential of NTN satellites in global communication, enhancing connectivity, reliability, and service availability across diverse environments and use cases.