ETSI TS 123 273 V19.6.0 (2026-03)

5G; 5G System (5GS) Location Services (LCS); Stage 2 (3GPP TS 23.273 version 19.6.0 Release 19)

RTS/TSGS-0223273vj60

General Information

• Status: Not Published
• Technical Committee: 3GPP SA 2 - Architecture
• Current Stage: 8 - Draft receipt by ETSI Secretariat
• Completion Date: 13-Mar-2026

Standards Content (Sample)

TECHNICAL SPECIFICATION
5G;
5G System (5GS) Location Services (LCS);
Stage 2
(3GPP TS 23.273 version 19.6.0 Release 19)

3GPP TS 23.273 version 19.6.0 Release 19 1 ETSI TS 123 273 V19.6.0 (2026-03)

Reference
RTS/TSGS-0223273vj60
Keywords
5G
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ETSI
3GPP TS 23.273 version 19.6.0 Release 19 2 ETSI TS 123 273 V19.6.0 (2026-03)
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3GPP TS 23.273 version 19.6.0 Release 19 3 ETSI TS 123 273 V19.6.0 (2026-03)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 8
1 Scope . 10
2 References . 10
3 Definitions and Abbreviations . 12
3.1 Definitions . 12
3.2 Abbreviations . 13
4 Architecture Model and Concepts . 14
4.1 General Concepts . 14
4.1a Types of Location Request . 15
4.1a.1 Network Induced Location Request (NI-LR) . 15
4.1a.2 Mobile Terminated Location Request (MT-LR). 15
4.1a.3 Mobile Originated Location Request (MO-LR) . 15
4.1a.4 Immediate Location Request . 15
4.1a.5 Deferred Location Request . 15
4.1a.5.1 Types of event . 15
4.1b LCS Quality of Service . 16
4.1c Scheduled Location Time . 17
4.2 Architectural Reference Model . 17
4.2.1 Non-roaming reference architecture . 17
4.2.2 Roaming reference architecture . 19
4.2.3 Reference architecture with sidelink positioning . 20
4.2a Interconnection between 5GC and EPC . 20
4.2a.1 General . 20
4.2a.2 Non-roaming architecture . 20
4.2a.3 Roaming architecture . 21
4.2b Positioning methods . 23
4.3 Functional description of LCS per network function . 23
4.3.1 Access Network . 23
4.3.2 LCS Clients, Application Functions and Network Functions . 24
4.3.3 Gateway Mobile Location Centre, GMLC . 24
4.3.4 Location Retrieval Function, LRF . 25
4.3.5 UE . 25
4.3.6 UDM . 26
4.3.7 Access and Mobility Management Function, AMF . 26
4.3.8 Location Management Function, LMF . 27
4.3.9 Network Exposure Function, NEF . 30
4.3.10 Unified Data Repository, UDR . 30
4.3.11 Positioning Reference Unit, PRU . 30
4.3.12 Network Repository Function, NRF . 31
4.3.13 Network Data Analytics Function, NWDAF . 31
4.4 Reference Point to Support Location Services . 31
4.4.1 Le Reference Point. 31
4.4.2 NL3 Reference Point . 31
4.4.3 N1 Reference Point . 32
4.4.4 N2 Reference Point . 32
4.4.5 Void . 32
4.4.6 NL5 Reference Point . 32
4.4.7 NL2 Reference Point . 32
4.4.8 NL6 Reference Point . 32
4.4.9 N51 Reference Point . 32
4.4.10 NL1 Reference Point . 32
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4.4.11 N52 Reference Point . 32
4.4.12 NL7 Reference Point . 33
4.4.13 NL8 Reference Point . 33
4.4.14 NL9 Reference Point . 33
4.4.15 NL10 Reference Point . 33
4.4.16 NL11 Reference Point . 33
4.5 Service Based Interfaces to Support Location Services . 33
5 High Level Features . 33
5.1 LMF Discovery and Selection . 33
5.1a GMLC Discovery and Selection . 35
5.2 3GPP access specific aspects. 35
5.3 Non-3GPP Access Specific Aspects . 35
5.3.1 Location Information for Non-3GPP Access . 35
5.3.2 Access Type Selection for LCS Service . 36
5.4 UE LCS privacy . 37
5.4.1 General . 37
5.4.2 Content of UE LCS Privacy Profile . 37
5.4.2.1 General . 37
5.4.2.2 Privacy Classes . 38
5.4.2.2.1 Universal Class . 38
5.4.2.2.2 Call/Session related Class . 38
5.4.2.2.3 Call/Session unrelated Class . 38
5.4.2.2.4 PLMN Operator Class . 38
5.4.2.3 Location Privacy Indication (LPI) . 39
5.4.3 Provision of UE LCS privacy profile . 39
5.4.4 Privacy Override Indicator (POI) . 39
5.4.5 LCS service authorization for an Immediate UE Location . 39
5.4.6 LCS service authorization for a Deferred UE Location . 40
5.5 Location service exposure . 41
5.6 LCS Charging . 43
5.7 Support of Concurrent Location Requests . 43
5.7.1 General . 43
5.7.2 Combining location requests by an H-GMLC or NEF . 44
5.7.3 Combining location requests by a V-GMLC . 44
5.7.4 Combining location requests by an AMF . 44
5.7.5 Combining location requests by an LMF . 44
5.7.6 Combining location requests by a UE. 44
5.8 Interworking with the IMS . 45
5.9 Location Service involving Mobile Base Station Relay . 45
5.9.1 General . 45
5.9.2 Obtaining location information for the MBSR . 45
5.9.3 Privacy check for MBSR . 45
5.10 Support of Positioning over user plane connection between UE and LMF for non-regulatory service . 46
5.11 Collection of GNSS assistance data . 46
5.12 UE Unaware Positioning . 47
5.13 Support of location service in PNI-NPN with signalling optimisation . 47
5.14 Event Report Allowed Area . 48
5.15 Support of Low Power and High Accuracy Positioning. 48
5.16 Location services assisted by NWDAF . 48
5.16A Network data analytics assisted by LCS. 49
5.16B LCS Continuity During UE Mobility . 49
5.16B.1 Mobility Between 5GS and EPS . 49
5.17 Support of Ranging and Sidelink Positioning . 49
5.18 Support for UE positioning based on a ML Model at the LMF. 49
5.18.0 General . 49
5.18.1 Void . 51
5.18.2 AI/ML model performance monitoring for LMF-based AI/ML Positioning . 51
5.19 Location Service involving Mobile Wireless Access Backhaul . 51
5.19.1 General . 51
5.19.2 Obtaining location information for the MWAB. 52
5.19.3 Privacy check for MWAB . 52
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6 Location Service Procedures . 52
6.1 5GC-MT-LR Procedure . 52
6.1.1 5GC-MT-LR procedure for the regulatory location service . 52
6.1.2 5GC-MT-LR Procedure for the commercial location service . 54
6.1.3 5GC-MT-LR multiple location procedure for the regulatory location service . 59
6.1.4 5GC-MT-LR procedure involving Mobile Base Station Relay . 61
6.1.5 5GC-MT-LR procedure involving MWAB . 63
6.2 5GC-MO-LR Procedure . 66
6.3 Deferred 5GC-MT-LR Procedure for Periodic, Triggered and UE Available Location Events . 69
6.3.1 Initiation and Reporting of Location Events . 69
6.3.2 Cancellation of Reporting of Location Events by a UE . 76
6.3.3 Cancellation of Reporting of Location Events by an AF, an NF or External LCS Client or GMLC . 77
6.3.4 Cancellation of Reporting of data collection by a UE . 78
6.3.5 Deferred 5GC-MT-LR Procedure for Periodic Location Events based on NRPPa Periodic
Measurement. 79
6.3.5.1 Initiation and Reporting of Periodic Events based on NRPPa Periodic Measurement . 79
6.3.5.2 Cancellation of Reporting of Periodic Events by an AF, an NF or External LCS Client or GMLC . 80
6.4 LMF Change Procedure . 80
6.4.0 General . 80
6.4.1 LMF Change Procedure for NRPPa Periodic Measurement . 82
6.5 Unified Location Service Exposure Procedure . 83
6.5.1 Unified Location Service Exposure Procedure without routing by a UDM . 83
6.5.2 Unified Location Service Exposure Procedure with routing via a UDM . 86
6.6 NG-RAN Location Service Exposure Procedure . 87
6.7 Low Power Periodic and Triggered 5GC-MT-LR Procedures . 87
6.7.1 Event Reporting with no change of LMF . 88
6.7.2 Event Reporting with change of LMF . 90
6.7.3 Event Reporting in RRC INACTIVE state for DL Positioning, RAT Independent Positioning or No
Positioning . 90
6.7.4 Event Reporting in RRC INACTIVE state for UL Positioning . 92
6.7.5 Event Reporting in RRC INACTIVE state for UL+DL Positioning . 95
6.8 Bulk Operation of LCS Service Request Targeting to Multiple UEs . 98
6.9 Procedures to Support Non-3GPP Access . 100
6.9.1 Common Positioning Procedures when a UE is served by only one PLMN . 100
6.9.2 MT-LR Procedures when a UE is served by Different PLMNs for 3GPP Access and Non-3GPP
Access . 102
6.9.3 MO-LR Procedures when UE is served by the Different PLMNs via 3GPP Access and Non-3GPP
Access . 105
6.9.4 NI-LR Procedures when a UE is served by Different PLMNs for 3GPP access and non-3GPP access . 105
6.10 Procedures dedicated to Support Regulatory services . 105
6.10.1 5GC-NI-LR Procedure . 105
6.10.2 5GC-MT-LR Procedure without UDM Query . 107
6.10.3 Location continuity for Handover of an Emergency session from NG-RAN . 108
6.10.4 5GC-MT-LR multiple location procedure without UDM Query . 110
6.10.5 Multiple location procedure for multiple emergency LCS clients . 111
6.11 Common Sub-Procedures . 111
6.11.0 General . 111
6.11.1 UE Assisted and UE Based Positioning Procedure . 111
6.11.2 Network Assisted Positioning Procedure . 113
6.11.3 Obtaining Non-UE Associated Network Assistance Data . 114
6.11.4 Positioning Procedure over User Plane . 114
6.12 UE Location Privacy Setting Procedure . 115
6.12.1 UE Location Privacy Setting Procedure Initiated by UE . 115
6.12.2 UE Location Privacy Setting Procedure Initiated by AF . 116
6.13 Procedures with interaction between 5GC and EPC . 116
6.13.1 MT-LR Procedure . 116
6.13.2 MO-LR Transfer to a Third Party Procedure . 118
6.14 Procedures for Broadcast of Assistance Data . 119
6.14.1 Broadcast of Assistance Data by an LMF . 119
6.14.2 Delivery of Ciphering Keys to UEs for Broadcast Assistance Data . 121
6.15 Procedures for GNSS assistance data Collection . 122
6.15.1 GNSS assistance data collection from untrusted AF via NEF . 122
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6.15.2 GNSS assistance data collection from trusted AF . 123
6.16 Periodic and Triggered 5GC-MT-LR Procedure with User Plane . 124
6.16.1 Reporting of Location Events to an LCS Client or AF via user plane . 124
6.16.2 Cancellation of Reporting of Location Events with a User Plane Connection . 126
6.17 Procedures applicable to a PRU . 127
6.17.1 PRU Association Procedure . 127
6.17.2 LMF Initiated PRU Disassociation Procedure . 129
6.17.3 PRU Initiated PRU Disassociation Procedure . 130
6.17.4 Positioning of a target UE . 131
6.18 Procedures of User Plane Connection between UE and LMF . 133
6.18.0 General . 133
6.18.1 LMF initiated User Plane Connection . 134
6.18.2 UE initiated User Plane Connection . 135
6.18.3 Modification of User Plane Connection between UE and LMF . 137
6.19 Location Service Continuity between EPS and 5GS . 139
6.19.0 General . 139
6.19.1 Location Service Continuity for Immediate Location Request . 139
6.19.1.1 Location Service Continuity from 5GS to EPS with N26 Interface for Immediate Location
Request . 139
6.19.1.2 Location Service Continuity from EPS to 5GS with N26 Interface for Immediate Location

Request . 141
6.19.1.3 Location Service Continuity from 5GS to EPS without N26 Interface for Immediate Location
Request . 142
6.19.1.4 Location Service Continuity from EPS to 5GS without N26 Interface for Immediate Location
Request . 143
6.19.2 Location Service Continuity between EPS and 5GS (bi-direction) for deferred MT-LR . 143
6.19.2.1 Location Service Continuity from 5GS to EPS . 144
6.19.2.2 Location Service Continuity from EPS to 5GS . 145
6.20 Ranging/Sidelink Positioning procedures . 146
6.20.1 Procedures of SL-MO-LR involving LMF . 146
6.20.2 5GC-MO-LR Procedure using Ranging/SL positioning . 150
6.20.3 Procedures of SL-MT-LR involving LMF . 151
6.20.4 Procedures of SL-MT-LR for periodic, triggered Location Events . 154
6.20.5 5GC-MT-LR Procedure using Ranging/SL positioning . 157
6.21 Procedure for NWDAF assistance to location services . 158
6.21.1 General . 158
6.21.1 Location Accuracy Analytics Retrieval by LMF . 159
6.21.2 UE Mobility Analytics Retrieval by AMF . 159
6.22 Procedures of data collection for LMF-based AI/ML Positioning . 159
6.22.1 General . 159
6.22.2 Void . 159
6.22.3 Data collection to train models for LMF-based AI/ML positioning based on NG RAN measurements . 159
6.22.4 Input data collection by NWDAF for AI/ML positioning ML model training or ML model
performance monitoring . 161
6.22.5 LMF retrieval of a trained AI/ML Model for positioning . 163
6.23 Procedures of data collection for NG RAN-sided models for AI/ML positioning . 164
6.23.1 General . 164
6.23.2 Data Collection for NG RAN-sided models for UEs under positioning . 164
7 Information storage . 165
7.1 UDM . 165
7.2 GMLC . 168
7.2.1 Information for an LCS Client . 168
8 Network Function Services . 170
8.1 AMF Services . 170
8.2 UDM Services . 170
8.3 LMF Services . 170
8.3.1 General . 170
8.3.2 Nlmf_Location service . 170
8.3.2.1 General . 170
8.3.2.2 Nlmf_Location_DetermineLocation service operation . 171
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8.3.2.3 Nlmf_Location_EventNotify service operation . 171
8.3.2.4 Nlmf_Location_CancelLocation service operation . 172
8.3.2.5 Nlmf_Location_LocationContextTransfer service operation . 172
8.3.2.6 Nlmf_Location_MeasurementData service operation . 172
8.3.2.7 Nlmf_Location_UPConfig service operation . 173
8.3.2.8 Nlmf_Location_UPSubscribe service operation . 173
8.3.2.9 Nlmf_Location_UPNotify service operation . 173
8.3.2.10 Nlmf_Location_UPUnSubscribe service operation . 173
8.3.3 Nlmf_Broadcast service . 174
8.3.3.1 General . 174
8.3.3.2 Nlmf_Broadcast_CipheringKeyData service operation . 174
8.3.4 Nlmf_DataExposure service . 174
8.3.4.1 General . 174
8.3.4.2 Nlmf_DataExposure_Subscribe service operation . 174
8.3.4.3 Nlmf_DataExposure_Notify service operation . 175
8.3.4.4 Nlmf_DataExposure_UnSubscribe service operation . 175
8.4 GMLC Services . 175
8.4.1 General . 175
8.4.2 Ngmlc_Location service .
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