efined in 3GPP TS 38.213 seems beneficial for NTN scenarios and should be used in mobility scenarios to compensate for the path loss and adjust the signal power to an optimum target level. 5.3.6 NTN Channel Model The 3GPP NR channel model is defined in 3GPP TR 38.901 for terrestrial links. It was nec- essary to define a specific NTN channel model as it may differ from terrestrial channels for several reasons: The elevation angle between the satellite/HAPS and the UE can be much higher resulting in different scattering statistics. 2 AMC and ACM are used interchangeably in different specifications. 5.3 Non-terrestrial Networks Table 5.3.3 Objectives of non-terrestrial network (NTN) channel modeling. High Altitude Satellite Platforms (HAPS) Outdoor/indoor Only outdoor conditions Support frequency From 0.5 GHz up to 100 GHz range UE mobility Up to 1000 km/h Up to 500 km/h User environment Open, rural, suburban, urban, and dense urban The long distance between the satellite and the UE leads to almost no angular spread from the satellite. Atmospheric effects may attenuate the transmitted signal. An NTN channel model has therefore been defined in clause 6 of (3GPP TR 38.811) with modeling objectives summarized in Table 5.3.3. The methodology that was adopted is to consider a new satellite link model between the satellite/HAPS and the terrestrial model, as depicted in Figure 5.3.10. The satellite link consists of the dynamic delay and Doppler shift (for LEO satellites only) and the dynamic attenuation due to rain, clouds, and scintillation; the latter being described in ITU recommendations ITU-R P.681-10 and ITU-R P.618-13. The terrestrial part is similar to the 3GPP TR 38.901 channel model with a specific elevation-dependent parameterization obtained by ray-tracing simulations for all of the considered frequency bands and scenarios in line of sight and non-line of sight. As a simplified alternative to the fast-fading model defined in 3GPP TR 38.901, the flat-fading model defined in ITU-R P.681-10 may also be considered 