For the purposes of the present document, the terms and definitions given in
TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in
TR 21.905.
Availability:
% of time during which the RAN is available for the targeted communication. Unavailable communication for shorter period than [Y] ms shall not be counted. The RAN may contain several access network components.
Feeder link:
wireless link between NTN Gateway and satellite.
Geostationary Earth orbit:
circular orbit at 35,786 km above the Earth's equator and following the direction of the Earth's rotation. An object in such an orbit has an orbital period equal to the Earth's rotational period and thus appears motionless, at a fixed position in the sky, to ground observers.
Low Earth Orbit:
orbit around the Earth with an altitude between 300 km, and 1500 km.
Medium Earth Orbit:
region of space around the Earth above low Earth orbit and below geostationary Earth Orbit.
Minimum Elevation angle:
minimum angle under which the satellite or UAS platform can be seen by a terminal.
Mobile Services:
a radio-communication service between mobile and land stations, or between mobile stations.
Mobile Satellite Services:
a radio-communication service between mobile earth stations and one or more space stations, or between space stations used by this service; or between mobile earth stations by means of one or more space stations.
Non-Geostationary Satellites:
satellites (LEO and MEO) orbiting around the Earth with a period that varies approximately between 1.5 hour and 10 hours.
Non-terrestrial networks:
networks, or segments of networks, using an airborne or space-borne vehicle to embark a transmission equipment relay node or base station.
NTN-gateway:
an earth station or gateway is located at the surface of Earth, and provides sufficient RF power and RF sensitivity for accessing to the satellite. NTN Gateway is a transport network layer (TNL) node.
On Board processing:
digital processing carried out on uplink RF signals aboard a satellite or an aerial.
On board NTN eNB:
eNB implemented in the regenerative payload on board a satellite.
On ground NTN eNB:
eNB of a transparent satellite payload implemented on ground.
One-way latency:
time required to propagate through a telecommunication system from a terminal to the public data network or from the public data network to the terminal.
Regenerative payload:
payload that transforms and amplifies an uplink RF signal before transmitting it on the downlink. The transformation of the signal refers to digital processing that may include demodulation, decoding, re-encoding, re-modulation and/or filtering.
Round Trip Delay:
time required for a signal to travel from a terminal to the sat-gateway or from the sat-gateway to the terminal and back.
Satellite:
a space-borne vehicle embarking a bent pipe payload or a regenerative payload telecommunication transmitter, placed into Low-Earth Orbit (LEO), Medium-Earth Orbit (MEO), or Geostationary Earth Orbit (GEO).
Satellite beam:
a beam generated by an antenna on-board a satellite.
Service link:
radio link between satellite and UE.
Transparent payload:
payload that changes the frequency carrier of the uplink RF signal, filters and amplifies it before transmitting it on the downlink.
User Connectivity:
capability to establish and maintain data transfer between networks and terminals.
User Throughput:
data rate provided to a terminal.
For the purposes of the present document, the abbreviations given in
TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in
TR 21.905.
CHO
Conditional Handover
DRX
Discontinuous Reception
ECEF
Earth-Centred, Earth-Fixed
eDRX
Extended DRX
EIRP
Equivalent Isotropic Radiated Power
GEO
Geostationary Earth Orbiting
eNB
E-UTRAN Node B
GW
Gateway
LEO
Low Earth Orbiting
Mbps
Mega bit per second
MEO
Medium Earth Orbiting
MS
Mobile Services
MSS
Mobile Satellite Services
NGEO
Non-Geostationary Earth Orbiting
NTN
Non-Terrestrial Network
PSM
Power Saving Mode
PUR
Preconfigured Uplink Resource
RAN
Radio Access Network
RTD
Round Trip Delay
Rx
Receiver
SNR
Signal-to-Noise Ratio
TA
Timing Advance
TA
Tracking Area
TAC
Tracking Area Code
TAU
Tracking Area Update
TLE
Two-Line Element
UAS
Unmanned Aircraft System
UE
User Equipment
WI
Work Item
WID
Work Item Description
WUS
Wake Up Signal