Content for TR 38.811 Word version: 15.4.0
2 References
3 Definitions, symbols and abbreviations
4 Non-Terrestrial Networks Overview - background information
5 Non-Terrestrial Networks deployment scenarios
6 Non-Terrestrial Networks channel models
7 Potential key impact areas on NR to support NTN
8 Recommendations on the way forward
A Example of reference scenario for calibration of large scale parameters
B Non Terrestrial network characteristics
$ Change history
2 References p. 7
3 Definitions, symbols and abbreviations p. 10
4 Non-Terrestrial Networks Overview - background information p. 13
4.1 Roles for Non-Terrestrial Networks in 5G system p. 13
4.2 5G Use Cases wherein Non-Terrestrial Network components have a role p. 13
4.3 Satellite and aerial access network architecture principles p. 17
4.4 Characteristics of NTN Terminals for satellite / aerial access network p. 20
4.5 Air/Space borne vehicle characteristics p. 21
4.6 Coverage pattern of NTN p. 21
4.7 Non-Terrestrial Network architecture options p. 22
4.8 Spectrum p. 23
5 Non-Terrestrial Networks deployment scenarios p. 24
5.1 Scenarios overview p. 24
5.2 Attributes p. 25
5.3 Doppler and Propagation delay characterisation p. 26
5.3.1 Methodology p. 26
5.3.1.1 Propagation delay p. 26
5.3.1.2 Differential delay p. 26
5.3.1.3 Doppler shift/variation p. 26
5.3.2 Geo-stationary platforms p. 27
5.3.3 Aerial vehicle p. 32
5.3.4 Non geostationary satellites p. 33
5.3.4.1 Propagation delay p. 33
5.3.4.2 Differential delay p. 34
5.3.4.3 Doppler Shift and variation rate p. 34
5.3.4.3.1 Case at 2 GHz p. 36
5.3.4.3.2 Case in Ka band p. 37
5.3.4.4 Doppler Shift and variation rate p. 41
5.3.5 Synthesis for each scenarios p. 42
6 Non-Terrestrial Networks channel models p. 43
6.1 Status/expectation of existing information for satellite/HAPS channels p. 43
6.1.1 Channel modeling works outside of 3GPP p. 43
6.1.2 Targeted user environment p. 43
6.1.3 Modeling objectives p. 43
6.2 Differences between satellite/HAPS and cellular channel modelling p. 43
6.3 Coordinate system p. 45
6.4 Antenna modelling p. 45
6.4.1 HAPS/Satellite antenna p. 45
6.4.2 UE antenna pattern p. 46
6.5 Methodology to define channel models p. 46
6.6 Large scale model p. 48
6.6.1 LOS probability p. 48
6.6.2 Path loss and Shadow fading p. 48
6.6.3 O2I penetration loss p. 50
6.6.4 Atmospheric absorption p. 51
6.6.5 Rain and cloud attenuation p. 52
6.6.6 Scintillation p. 52
6.7 Fast fading model p. 58
6.7.1 Flat fading p. 58
6.7.2 Frequency selective fading p. 61
6.8 Additional modelling components p. 86
6.9 Channel models for link level simulations p. 88
6.9.1 CDL models p. 88
6.9.2 TDL models p. 91
6.10 Channel model calibration p. 94
7 Potential key impact areas on NR to support NTN p. 96
7.1 Specific constraints associated to NTN p. 96
7.2 NR features/protocols potentially affected p. 98
7.3 NR modifications to support the Non-Terrestrial Network deployment scenarios p. 101
7.3.1 Methodology p. 101
7.3.2 Motion of the space/aerial vehicles p. 101
7.3.2.1 Hand-Over and paging p. 101
7.3.2.1.1 Problem statement p. 101
7.3.2.1.2 Assessment of conditions for NR operation in Non-Terrestrial networks p. 102
7.3.2.1.3 NR impact considerations p. 102
7.3.2.2 TA adjustment p. 102
7.3.2.2.1 Problem statement p. 102
7.3.2.2.2 Assessment of conditions for NR operation in Non-Terrestrial networks p. 103
7.3.2.2.3 NR impact considerations p. 104
7.3.2.3 Initial synchronization in downlink p. 104
7.3.2.3.1 Problem statement p. 104
7.3.2.3.2 Assessment of conditions for NR operation in Non-Terrestrial networks p. 104
7.3.2.3.3 NR impact considerations p. 104
7.3.2.4 DMRS time density p. 105
7.3.3 Altitude of the space/aerial vehicles p. 106
7.3.3.1 HARQ p. 106
7.3.3.1.1 Problem statement p. 107
7.3.3.1.2 Assessment of conditions for NR operation in non-terrestrial networks p. 108
7.3.3.1.3 NR impact considerations p. 108
7.3.3.2 MAC/RLC procedures p. 108
7.3.3.2.1 Problem statement p. 108
7.3.3.2.2 Assessment of conditions for NR operation in Non-Terrestrial networks p. 108
7.3.3.2.3 NR impact considerations p. 109
7.3.3.3 Physical layer procedures (ACM, power control) p. 109
7.3.4 Cell size (Beam foot print) p. 109
7.3.4.1 PRACH and Random access p. 109
7.3.4.1.1 Problem statement p. 109
7.3.4.1.2 Assessment of conditions for NR operation in Non-Terrestrial networks p. 110
7.3.4.1.3 NR impact considerations p. 111
7.3.4.2 TA in Random access response message p. 111
7.3.5 Propagation channel p. 112
7.3.5.1 DMRS frequency density p. 112
7.3.5.1.1 Problem statement p. 112
7.3.5.1.2 Assessment of conditions for NR operation in Non-Terrestrial networks p. 113
7.3.5.1.3 NR impact considerations p. 113
7.3.5.2 Cyclic prefix p. 113
7.3.6 Duplex mode p. 114
7.3.7 Satellite or aerial Payload performance p. 115
7.3.7.1 PT-RS p. 115
7.3.7.1.1 Problem statement p. 115
7.3.7.1.2 Assessment of conditions for NR operation in Non-Terrestrial networks p. 115
7.3.7.1.3 NR impact considerations p. 116
7.3.7.2 PAPR p. 116
7.3.8 Network architecture p. 117
8 Recommendations on the way forward p. 122
8.1 General outcomes p. 122
8.2 Reference deployment scenarios p. 122
8.3 Non-Terrestrial network channel modelling p. 122
8.4 NR impacts to support Non-Terrestrial networks p. 122
A Example of reference scenario for calibration of large scale parameters p. 125
B Non Terrestrial network characteristics p. 126
B.1 NTN Phase noise masks p. 126
$ Change history p. 127
