3 Definitions, symbols and abbreviations
38.3053GPPNG Radio Access Network (NG-RAN)Release 17Stage 2 functional specification of User Equipment (UE) positioning in NG-RANTS
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 21.905 [1] 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 [1].
As used in this document, the suffixes "-based" and "-assisted" refer respectively to the node that is responsible for making the positioning calculation (and which may also provide measurements) and a node that provides measurements (but which does not make the positioning calculation). Thus, an operation in which measurements are provided by the UE to the LMF to be used in the computation of a position estimate is described as "UE-assisted" (and could also be called "LMF-based"), while one in which the UE computes its own position is described as "UE-based".
Positioning integrity: A measure of the trust in the accuracy of the position-related data and the ability to provide associated alerts.
Pre-configured assistance data: Refers to the DL-PRS assistance data (with associated validity criteria) that can be provided to the UE (before or during an ongoing LPP positioning session), to be then utilized for potential positioning measurements at a future time (e.g. for deferred MT-LR). Pre-configured DL-PRS assistance data may consist of multiple instances, where each instance is applicable to a different area within the network.
Protection Level (PL): A statistical upper-bound of the Positioning Error (PE) that ensures that, the probability per unit of time of the true error being greater than the AL and the PL being less than or equal to the AL, for longer than the TTA, is less than the required TIR, i.e., the PL satisfies the following inequality:
Prob per unit of time [((PE>AL) & (PL<=AL)) for longer than TTA] < required TIR
When the PL bounds the positioning error in the horizontal plane or on the vertical axis then it is called Horizontal Protection Level (HPL) or Vertical Protection Level (VPL) respectively.
A specific equation for the PL is not specified as this is implementation-defined. For the PL to be considered valid, it must simply satisfy the inequality above.
NOTE: the PL inequality is valid for all values of the AL.
PRS-only TP: A TP which only transmits PRS, DL-PRS signals and is not associated with a cell.
PRS Processing Window (PPW): The PRS Processing Window is configured by the network to a UE for NR DL-PRS measurements without measurement gap.
Reception Point (RP): A set of geographically co-located receive antennas (e.g. antenna array (with one or more antenna elements)) for one cell, part of one cell or one UL-SRS-only RP. Reception Points can include base station (ng-eNB or gNB) antennas, remote radio heads, a remote antenna of a base station, an antenna of a UL-SRS-only RP, etc. One cell can include one or multiple reception points. For a homogeneous deployment, each reception point may correspond to one cell.
Rx Time Delay: From a signal reception perspective, there will be a time delay from the time when the RF signal arrives at the Rx antenna to the time when the signal is digitized and time-stamped at the baseband.
Rx Timing Error: Result of Rx time delay involved in the reception of a signal before reporting measurements that are obtained from the signal. It is the uncalibrated Rx time delay, or the remaining delay after the UE/TRP internal calibration/compensation of the Rx time delay, involved in the reception of the DL-PRS/UL SRS signals. The calibration/compensation may also include the calibration/compensation of the relative time delay between different RF chains in the same UE/TRP and may also possibly consider the offset of the Rx antenna phase centre to the physical antenna centre.
SRS-only RP: An RP which only receives UL-SRS signals and is not associated with a cell.
Transmission Point (TP): A set of geographically co-located transmit antennas (e.g. antenna array (with one or more antenna elements)) for one cell, part of one cell or one DL-PRS-only TP. Transmission Points can include base station (ng-eNB or gNB) antennas, remote radio heads, a remote antenna of a base station, an antenna of a DL-PRS-only TP, etc. One cell can include one or multiple transmission points. For a homogeneous deployment, each transmission point may correspond to one cell.
Transmission-Reception Point (TRP): A set of geographically co-located antennas (e.g. antenna array (with one or more antenna elements)) supporting TP and/or RP functionality.
TRP Rx ‘Timing Error Group’ (TRP Rx TEG): Rx timing errors, associated with TRP reporting of one or more UL measurements, that are within a certain margin.
TRP RxTx ‘Timing Error Group’ (TRP RxTx TEG): Rx timing errors and Tx timing errors, associated with TRP reporting of one or more gNB Rx-Tx time difference measurements, which have the ‘Rx timing errors+Tx timing errors’ differences within a certain margin.
TRP Tx ‘Timing Error Troup’ (TRP Tx TEG): Tx timing errors, associated with TRP transmissions on one or more DL-PRS resources, that are within a certain margin.
Tx Time Delay: From a signal transmission perspective, the time delay from the time when the digital signal is generated at baseband to the time when the RF signal is transmitted from the Tx antenna.
Tx Timing Error: Result of Tx time delay involved in the transmission of a signal. It is the uncalibrated Tx time delay, or the remaining delay after the TRP/UE internal calibration/compensation of the Tx time delay, involved in the transmission of the DL-PRS/UL SRS signals. The calibration/compensation may also include the calibration/compensation of the relative time delay between different RF chains in the same TRP/UE and may also possibly consider the offset of the Tx antenna phase centre to the physical antenna centre.
UE Rx ‘Timing Error Group’ (UE Rx TEG): Rx timing errors, associated with UE reporting of one or more DL measurements (RSTD), that are within a certain margin.
UE RxTx ‘Timing Error Group’ (UE RxTx TEG): Rx timing errors and Tx timing errors, associated with UE reporting of one or more UE Rx-Tx time difference measurements, which have the ‘Rx timing errors+Tx timing errors’ differences within a certain margin.
UE Tx ‘Timing Error Group’ (UE Tx TEG): Tx timing errors, associated with UE transmissions on one or more UL SRS resources for positioning purpose, that are within a certain margin.
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in TR 21.905 [1] 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 [1].
5GC 5G Core Network
5GS 5G System
A-AoA Azimuth-Angle of Arrival
ADR Accumulated Delta Range
AoA Angle of Arrival
AP Access Point
ARP Antenna Reference Point
BDS BeiDou Navigation Satellite System
BSSID Basic Service Set Identifier
CID Cell-ID (positioning method)
CLAS Centimetre Level Augmentation Service
DL-AoD Downlink Angle-of-Departure
DL-PRS Downlink Positioning Reference Signal
DL-TDOA Downlink Time Difference Of Arrival
DNU Do Not Use
E-SMLC Enhanced Serving Mobile Location Centre
E-CID Enhanced Cell-ID (positioning method)
ECEF Earth-Centered, Earth-Fixed
ECI Earth-Centered-Inertial
EGNOS European Geostationary Navigation Overlay Service
E-UTRAN Evolved Universal Terrestrial Radio Access Network
FDMA Frequency Division Multiple Access
FKP Flächenkorrekturparameter (Engl: Area Correction Parameters)
GAGAN GPS Aided Geo Augmented Navigation
GLONASS GLObal’naya NAvigatsionnaya Sputnikovaya Sistema (Engl.: Global Navigation Satellite System)
GMLC Gateway Mobile Location Centre
GNSS Global Navigation Satellite System
GPS Global Positioning System
GRS80 Geodetic Reference System 1980
HESSID Homogeneous Extended Service Set Identifier
LCS LoCation Services
LMF Location Management Function
LPP LTE Positioning Protocol
MAC Master Auxiliary Concept
MBS Metropolitan Beacon System
MO-LR Mobile Originated Location Request
MT-LR Mobile Terminated Location Request
Multi-RTT Multi-Round Trip Time
NavIC NAVigation with Indian Constellation
NG-C NG Control plane
NG-AP NG Application Protocol
NI-LR Network Induced Location Request
N-RTK Network – Real-Time Kinematic
NRPPa NR Positioning Protocol A
OTDOA Observed Time Difference Of Arrival
PDU Protocol Data Unit
posSI Positioning System Information
posSIB Positioning SIB
PPP Precise Point Positioning
PPP-RTK Precise Point Positioning – Real-Time Kinematic
PRS Positioning Reference Signal (for E-UTRA)
PRU Positioning Reference Unit
QZSS Quasi-Zenith Satellite System
RP Reception Point
RRM Radio Resource Management
RSRP Reference Signal Received Power
RSRPP Reference Signal Received Path Power
RSRQ Reference Signal Received Quality
RSSI Received Signal Strength Indicator
RSTD Reference Signal Time Difference
RTK Real-Time Kinematic
SBAS Space Based Augmentation System
SDT Small Data Transmission
SET SUPL Enabled Terminal
SIB System Information Block
SLP SUPL Location Platform
SP Semi-Persistent
SRS Sounding Reference Signal
SSB Synchronization Signal Block
SSID Service Set Identifier
SSR State Space Representation
STEC Slant TEC
SUPL Secure User Plane Location
TADV Timing Advance
TBS Terrestrial Beacon System
TEC Total Electron Content
TEG Timing Error Group
TP Transmission Point
TRP Transmission-Reception Point
TTA Time To Alert
TxTEG Tx Timing Error Group
UE User Equipment
UL-AoA Uplink Angle of Arrival
UL-RTOA Uplink Relative Time of Arrival
UL-SRS Uplink Sounding Reference Signal
UL-TDOA Uplink Time Difference of Arrival
URA User Range Accuracy
WAAS Wide Area Augmentation System
WGS-84 World Geodetic System 1984
WLAN Wireless Local Area Network
Z-AoA Zenith Angles of Arrival