The Wiley whitepaper identifies six technical challenges for satellite links: high free-space path loss, time-variant Doppler, differential delay across large beam footprints, Faraday rotation of polarization through the ionosphere, spectrum coexistence in S-band and L-band, and overall architecture integration (https://content.knowledgehub.wiley.com/5g-ntn-takes-flight-technical-overview-of-5g-non-terrestrial-networks/). 3GPP Release 17 specifies New Radio non-terrestrial networks for mobile broadband and Internet of Things non-terrestrial networks for low-power machine-type communications.

Satellite constellation parameters including low earth orbit, medium earth orbit, and geostationary earth orbit altitudes determine coverage area, round-trip time, and differential delay, alongside beam footprint geometry, elevation angle, and inclination (https://content.knowledgehub.wiley.com/5g-ntn-takes-flight-technical-overview-of-5g-non-terrestrial-networks/). Trade-offs are detailed between transparent bent-pipe payloads and regenerative onboard-processing architectures.

Protocol adaptations encompass hybrid automatic repeat request operation, timing advance split into common and user-equipment-specific components, extended random access procedure timing, discontinuous reception modifications, earth-fixed tracking area management, conditional handover, and feeder link switching for service continuity (https://content.knowledgehub.wiley.com/5g-ntn-takes-flight-technical-overview-of-5g-non-terrestrial-networks/).