1.1Defining NTN: Spaceborne (LEO, GEO, MEO) & Airborne (HAPS, UAS) platforms
1.2Key Components: Service Link, Feeder Link, NTN Gateway, ISL.
1.3Payload Types: Transparent (bent-pipe) vs. Regenerative (on-board processing) - "Mirror vs. Computer" analogy
1.4The Six Reference Scenarios (A, B, C1, C2, D1, D2) based on TR 38.821 Table 4.2-1/2
1.5Critical Metrics: Round Trip Delay (RTD), Doppler Shift, Differential Delay
1.6Examples: Comparing a GEO transparent satellite (Scenario A) for broadcasting with a LEO regenerative moving-beam satellite (Scenario D2/Starlink) for low-latency broadband