Transparent payload

• In a Transparent Payload scenario, the satellite operates as an analog radio frequency repeater.
• Digital processing is done at gNB at GW.
• It serves both the feeder and service links without modifying the transmitted signals.
• Specifically in the context of 5G, the satellite, including Unmanned Aerial Systems (UAS), acts as a medium for replicating the 5G NR-Uu radio interface.
• The satellite does not alter the signals passing through it.
• It ensures the seamless transmission of data from the feeder link to the service link.
• This mode simplifies satellite’s role to relay 5G signals without making changes to the content or format of the data.

Reference: 38.821-Transparent Payload

Non-Transparent (Regenerative) payload:

The satellite plays a central role in signal regeneration, bridging communication between Earth and the satellite network.

• The NR-Uu interface functions on the service link, facilitating communication with user equipment.
• On the feeder link, the satellite employs N2 and N3 interfaces, forming a satellite radio interface.
• This setup effectively positions the gNB (5G base station) within the satellite, enabling enhanced signal processing and relay capabilities.
• The regenerative payload actively enhances signals, which can include error correction, modulation/demodulation, and amplification.
• Regenerative payloads support bidirectional communication, enabling data exchange between Earth-based stations and user equipment through the satellite.
• Data may undergo transformation within the payload to align with satellite network requirements, ensuring efficient and reliable transmission.
• Operators gain increased control over signal quality, network performance, and data integrity.
• Implementing a regenerative payload adds complexity and cost to satellite systems, but it offers substantial advantages in terms of signal optimization and network reliability.

Reference: 38.821 Non-Transparent or Regenerative Payload