ETSI TS 137 571-2 V18.5.0 (2026-04)

Universal Mobile Telecommunications System (UMTS); LTE; 5G; User Equipment (UE) conformance specification for UE positioning; Part 2: Protocol conformance (3GPP TS 37.571-2 version 18.5.0 Release 18)

RTS/TSGR-0537571-2vi50

General Information

• Status: Not Published
• Technical Committee: 3GPP RAN 5 - Mobile Terminal Conformance Testing (formely T1)
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Completion Date: 02-Apr-2026

Standards Content (Sample)

TECHNICAL SPECIFICATION
Universal Mobile Telecommunications System (UMTS);
LTE;
5G;
User Equipment (UE)
conformance specification for UE positioning;
Part 2: Protocol conformance
(3GPP TS 37.571-2 version 18.5.0 Release 18)

3GPP TS 37.571-2 version 18.5.0 Release 18 1 ETSI TS 137 571-2 V18.5.0 (2026-04)

Reference
RTS/TSGR-0537571-2vi50
Keywords
5G,LTE,UMTS
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - APE 7112B
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° w061004871

Important notice
The present document can be downloaded from the
ETSI Search & Browse Standards application.
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI
deliverable is the one made publicly available in PDF format on ETSI deliver repository.
Users should be aware that the present document may be revised or have its status changed,
this information is available in the Milestones listing.
If you find errors in the present document, please send your comments to
the relevant service listed under Committee Support Staff.
If you find a security vulnerability in the present document, please report it through our
Coordinated Vulnerability Disclosure (CVD) program.
Notice of disclaimer & limitation of liability
The information provided in the present deliverable is directed solely to professionals who have the appropriate degree of
experience to understand and interpret its content in accordance with generally accepted engineering or
other professional standard and applicable regulations.
No recommendation as to products and services or vendors is made or should be implied.
No representation or warranty is made that this deliverable is technically accurate or sufficient or conforms to any law
and/or governmental rule and/or regulation and further, no representation or warranty is made of merchantability or fitness
for any particular purpose or against infringement of intellectual property rights.
In no event shall ETSI be held liable for loss of profits or any other incidental or consequential damages.

Any software contained in this deliverable is provided "AS IS" with no warranties, express or implied, including but not
limited to, the warranties of merchantability, fitness for a particular purpose and non-infringement of intellectual property
rights and ETSI shall not be held liable in any event for any damages whatsoever (including, without limitation, damages
for loss of profits, business interruption, loss of information, or any other pecuniary loss) arising out of or related to the use
of or inability to use the software.
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© ETSI 2026.
All rights reserved.
ETSI
3GPP TS 37.571-2 version 18.5.0 Release 18 2 ETSI TS 137 571-2 V18.5.0 (2026-04)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations
pertaining to these essential IPRs, if any, are publicly available for ETSI members and non-members, and can be
found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to
ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the
ETSI IPR online database.
Pursuant to the ETSI Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,
including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not
referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become,
essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its
Members. 3GPP™, LTE™ and 5G™ logo are trademarks of ETSI registered for the benefit of its Members and of the
3GPP Organizational Partners. oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and of ®
the oneM2M Partners. GSM and the GSM logo are trademarks registered and owned by the GSM Association.
Legal Notice
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities. These shall be
interpreted as being references to the corresponding ETSI deliverables.
The cross reference between 3GPP and ETSI identities can be found at 3GPP to ETSI numbering cross-referencing.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
3GPP TS 37.571-2 version 18.5.0 Release 18 3 ETSI TS 137 571-2 V18.5.0 (2026-04)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 13
Introduction . 13
1 Scope . 14
2 References . 14
3 Definitions and abbreviations . 16
3.1 Definitions . 16
3.2 Abbreviations . 16
4 Default Conditions for UTRAN . 16
4.1 Default system information . 16
4.2 Simulated A-GPS and A-GNSS environment . 17
4.2.1 A-GNSS sub-test cases . 17
4.3 A-GPS assistance data sets . 17
4.3.1 Adequate assistance data for UE-based A-GPS . 18
4.3.2 Inadequate assistance data for UE-based A-GPS . 18
4.3.3 Adequate assistance data for UE-assisted A-GPS . 18
4.3.4 Inadequate assistance data for UE-assisted A-GPS . 19
4.3.5 Response to assistance data requests from UE . 19
4.4 A-GNSS assistance data sets . 20
4.4.1 Adequate assistance data for UE-based A-GNSS . 21
4.4.1.1 Sub-Test 1 . 21
4.4.1.2 Sub-Test 2 . 22
4.4.1.3 Sub-Test 3 . 23
4.4.1.4 Sub-Test 4 . 24
4.4.1.4A Sub-Test 8 . 25
4.4.1.5 Sub-Test 9 . 28
4.4.1.6 Sub-Test 10 . 28
4.4.2 Inadequate assistance data for UE-based A-GNSS . 29
4.4.3 Adequate assistance data for UE-assisted A-GNSS . 29
4.4.3.1 Sub-Test 1 . 30
4.4.3.2 Sub-Test 2 . 31
4.4.3.3 Sub-Test 3 . 32
4.4.3.4 Sub-Test 4 . 33
4.4.3.4A Sub-Test 8 . 34
4.4.3.5 Sub-Test 9 . 35
4.4.3.6 Sub-Test 10 . 36
4.4.4 Inadequate assistance data for UE-assisted A-GNSS . 36
4.4.5 Response to assistance data requests from UE . 36
5 Default Conditions for E-UTRAN . 38
5.1 LCS Sub-Test Cases . 38
5.2 Default signal conditions . 38
5.2.1 Simulated GNSS environment . 38
5.2.2 Simulated OTDOA environment . 39
5.2.3 Simulated ECID environment . 39
5.2.4 Simulated MBS environment . 39
5.2.5 Simulated WLAN environment . 39
5.2.6 Simulated Bluetooth environment . 39
5.2.7 Simulated Sensor environment . 39
5.3 Default RRC and NAS message and information elements contents . 39
- ATTACH ACCEPT . 40
ETSI
3GPP TS 37.571-2 version 18.5.0 Release 18 4 ETSI TS 137 571-2 V18.5.0 (2026-04)
5.4 Default LPP message and information elements contents . 40
- LPP REQUEST CAPABILITIES . 41
- LPP PROVIDE ASSISTANCE DATA . 42
- LPP REQUEST LOCATION INFORMATION . 45
- A-GNSS REQUEST LOCATION INFORMATION . 46
- OTDOA REQUEST LOCATION INFORMATION . 46
- ECID REQUEST LOCATION INFORMATION . 46
- TBS REQUEST LOCATION INFORMATION . 47
- WLAN REQUEST LOCATION INFORMATION . 47
- BT REQUEST LOCATION INFORMATION . 47
- SENSOR REQUEST LOCATION INFORMATION . 47
5.4.1 Default assistance data information elements . 47
5.4.1.1 GNSS Assistance Data Elements . 47
5.4.1.2 OTDOA Assistance Data Elements . 48
- OTDOA REFERENCE CELL INFO . 49
- OTDOA NEIGHBOUR CELL INFO LIST . 50
5.4.1.3 MBS Assistance Data Elements . 52
5.4.1.4 WLAN Assistance Data Elements . 55
5.4.1.5 Sensor Assistance Data Elements . 56
6 Protocol Conformance Test Cases for UTRAN . 57
6.1 Assisted-GPS Test Cases . 57
6.1.1 Assisted GPS Network Induced Tests . 57
6.1.1.1 LCS Network Induced location request/ UE-Based GPS/ Emergency Call / with USIM . 57
6.1.1.2 LCS Network Induced location request/ UE-Based GPS/ Emergency Call / without USIM . 62
6.1.1.3 LCS Network induced location request/ UE-Assisted GPS/ Emergency call/ With USIM . 67
6.1.1.4 LCS Network induced location request/ UE-Assisted GPS/ Emergency call/ Without USIM . 72
6.1.2 Assisted GPS Mobile Originated Tests . 77
6.1.2.1 LCS Mobile originated location request/ UE-Based GPS/ Position estimate request/ Success . 77
6.1.2.2 LCS Mobile originated location request/ UE-Based or UE-Assisted GPS/ Assistance data
request/ Success . 82
6.1.2.3 LCS Mobile originated location request/ UE-Assisted GPS/ Position Estimate/ Success . 84
6.1.2.4 LCS Mobile originated location request/ UE-Based GPS/ Transfer to third party/ Success . 90
6.1.2.5 LCS Mobile originated location request/ UE-Assisted GPS/ Transfer to third party/ Success . 96
6.1.2.6 LCS Mobile originated location request/ UE-Based or UE-Assisted GPS/ Assistance data
request/ Failure . 101
6.1.2.7 LCS Mobile originated location request/ UE-Based GPS/ Position estimate request/ Failure . 104
6.1.3 Assisted GPS Mobile Terminated Tests . 110
6.1.3.1 LCS Mobile terminated location request/ UE-Based GPS . 110
6.1.3.2 LCS Mobile-terminated location request/UE-Based GPS/ Request for additional assistance data/
Success . 116
6.1.3.3 LCS Mobile-terminated location request/UE-Based GPS/ Failure – Not Enough Satellites . 123
6.1.3.4 LCS Mobile terminated location request/ UE-Assisted GPS/ Success . 130
6.1.3.5 LCS Mobile terminated location request/ UE-Assisted GPS/ Request for additional assistance
data/ Success . 135
6.1.3.6 LCS Mobile terminated location request/ UE-Based GPS/ Privacy Verification/ Location
Allowed if No Response . 140
6.1.3.7 LCS Mobile terminated location request/ UE-Based GPS/ Privacy Verification/ Location Not
Allowed if No Response . 150
6.1.3.8 LCS Mobile terminated location request/ UE-Assisted GPS/ Privacy Verification/ Location
Allowed if No Response . 157
6.1.3.9 LCS Mobile terminated location request/ UE-Assisted GPS/ Privacy Verification/ Location Not
Allowed if No Response . 168
6.1.3.10 LCS Mobile terminated location request/ UE-Based or UE-Assisted GPS/ Configuration
Inco mplete . 175
6.2.1 Assisted GNSS Network Induced Tests . 179
6.2.1.1 NI-LR Emergency Call: UE-Based A-GNSS . 179
6.2.1.2 NI-LR Emergency call: UE-Assisted A-GNSS . 186
6.2.2 Assisted GNSS Mobile Originated Tests . 192
6.2.2.1 MO-LR Position Estimate: UE-Based A-GNSS . 192
6.2.2.2 MO-LR Position Estimate: UE-Assisted A-GNSS . 199
6.2.2.3 MO-LR Position Estimate: UE-Based A-GNSS – Failure Not Enough Satellites . 204
ETSI
3GPP TS 37.571-2 version 18.5.0 Release 18 5 ETSI TS 137 571-2 V18.5.0 (2026-04)
6.2.2.4 MO-LR Assistance Data: UE-Based or UE-Assisted A-GNSS - Success . 213
6.2.2.5 MO-LR Assistance Data: UE-Based or UE-Assisted A-GNSS - Failure . 216
6.2.3 Assisted GNSS Mobile Terminated Tests . 219
6.2.3.1 MT-LR: UE-based or UE-Assisted A-GNSS – Request for additional assistance data/ Success . 219
6.2.3.2 MT-LR Position Estimate: UE-Based A-GNSS – Failure Not Enough Satellites . 230
6.2.3.3 Location Notification . 239
6.2.3.4 Privacy Verification - Location Allowed if No Response . 241
6.2.3.5 Privacy Verification - Location Not Allowed if No Response . 244
7 Protocol Conformance Test Cases for E-UTRAN . 248
7.1 NAS Protocol Procedures . 248
7.1.1 UE Network Capability . 248
7.2 LCS Procedures . 251
7.2.1 Location Notification and Privacy Verification . 251
7.2.1.1 Location Notification . 251
7.2.1.2 Privacy Verification – Location Allowed if no Response . 254
7.2.1.3 Privacy Verification – Location not Allowed if No Response . 260
7.2.2 EPC MO-LR . 265
7.2.2.1 Autonomous Self Location: UE-based . 265
7.2.2.2 Basic Self Location: UE-assisted . 271
7.3 LPP Procedures . 285
7.3.1 LPP Common Procedures . 285
7.3.1.1 Position Capability Transfer. 285
7.3.2 LPP Transport . 301
7.3.2.1 LPP Duplicated Message . 301
7.3.2.2 LPP Acknowledgment . 306
7.3.2.3 LPP Retransmission . 311
7.3.3 LPP Error Handling . 316
7.3.3.1 Void. 316
7.3.3.1A Void. 316
7.3.3.1B LPP Requested Method not Supported – UE-Assisted . 316
7.3.4 LPP Positioning Procedures . 324
7.3.4.1 E-SMLC Initiated Assistance Data Delivery followed by Location Information Transfer: UE-
Based . 324
7.3.4.2 E-SMLC Initiated Assistance Data Delivery followed by Location Information Transfer:
UE-Assisted . 332
7.3.4.3 E-SMLC Initiated Position Measurement without assistance data: UE-Based . 342
7.3.4.4 E-SMLC Initiated Position Measurement without assistance data: UE-Assisted . 351
7.3.5 LPP Abort . 363
7.3.5.1 E-SMLC initiated Abort . 363
7.4 Circuit Switched (CS) Fallback . 373
7.4.1 MO-LR Procedure . 373
7.4.1.1 CS fallback: Network does not support EPC-MO-LR . 373
7.4.1.2 CS fallback: UE does not support EPC-MO-LR . 376
7.5 RRC Protocol Procedures . 379
7.5.1 Inter-frequency RSTD measurement indication . 379
7.5.2 Void . 392
8 Default Conditions for NR . 392
8.1 LCS Sub-Test Cases . 392
8.1A Test Configurations . 393
8.2 Default signal conditions . 393
8.2.1 Simulated GNSS environment . 393
8.2.2 Simulated OTDOA (LTE) environment . 393
8.2.3 Simulated ECID (LTE) environment . 394
8.2.4 Simulated MBS environment . 394
8.2.5 Simulated WLAN environment . 394
8.2.6 Simulated Bluetooth environment . 394
8.2.7 Simulated Sensor environment . 394
8.2.8 Simulated general NR environment . 394
8.2.9 Simulated Multi-RTT environment . 395
8.2.10 Simulated DL-AoD environment . 395
ETSI
3GPP TS 37.571-2 version 18.5.0 Release 18 6 ETSI TS 137 571-2 V18.5.0 (2026-04)
8.2.11 Simulated DL-TDOA environment . 395
8.2.12 Simulated NR E-CID environment . 395
8.2.13 Simulated UL-TDOA environment . 395
8.2.14 Simulated SL-RTT environment . 396
8.2.15 Simulated SL-AoA environment . 396
8.2.16 Simulated SL-TDOA environment . 396
8.2.17 Simulated SL-TOA environment . 396
8.3 Default RRC and NAS message and information elements contents . 397
8.3.1 RRC message contents for measurement gaps. 397
8.3.2 RRC message contents for UL-SRS Configuration . 400
8.3.3 RRC message contents for SL-PRS Configuration . 403
8.4 Default LPP message and information elements contents . 405
- LPP PROVIDE ASSISTANCE DATA . 406
- LPP REQUEST CAPABILITIES . 410
- LPP REQUEST LOCATION INFORMATION . 412
- NR E-CID REQUEST LOCATION INFORMATION. 414
- NR Multi-RTT REQUEST LOCATION INFORMATION . 414
- NR DL-AoD REQUEST LOCATION INFORMATION . 415
- NR DL-TDOA REQUEST LOCATION INFORMATION . 415
8.4.1 Default assistance data information elements . 415
8.4.1.1 GNSS Assistance Data Elements . 415
8.4.1.2 OTDOA (LTE) Assistance Data Elements . 416
- OTDOA (LTE) REFERENCE CELL INFO . 417
- OTDOA (LTE) NEIGHBOUR CELL INFO LIST . 418
8.4.1.3 MBS Assistance Data Elements . 420
8.4.1.4 WLAN Assistance Data Elements . 420
8.4.1.5 Sensor Assistance Data Elements . 420
8.4.1.6 Multi-RTT Assistance Data Elements . 420
- NR DL-PRS ASSISTANCE DATA . 421
- NR-SelectedDL-PRS-IndexList . 425
- NR-DL-PRS-Info . 426
8.4.1.7 DL-AoD Assistance Data Elements . 428
- NR-PositionCalculationAssistance . 429
8.4.1.8 DL-TDOA Assistance Data Elements . 431
8.5 Default SLPP message and information elements contents . 431
- SLPP REQUEST CAPABILITIES . 432
- SLPP PROVIDE ASSISTANCE DATA . 433
- SLPP REQUEST LOCATION INFORMATION . 435
- CommonIEsRequestLocationInformation . 436
- SL-AoA REQUEST LOCATION INFORMATION . 436
- SL-RTT REQUEST LOCATION INFORMATION . 437
- SL-TDOA REQUEST LOCATION INFORMATION . 437
- SL-TOA REQUEST LOCATION INFORMATION . 437
8.5.1 Default assistance data information elements . 437
8.5.1.1 Common SL-PRS Assistance Data Elements. 437
8.5.1.2 SL-AoA Assistance Data Elements . 440
8.5.1.3 SL-RTT Assistance Data Elements . 441
8.5.1.4 SL-TDOA Assistance Data Elements . 441
8.5.1.5 SL-TOA Assistance Data Elements . 443
9 Protocol Conformance Test Cases for NR . 444
9.1 FFS . 444
9.2 FFS . 444
9.3 LPP Procedures . 444
9.3.1 LPP Common Procedures . 444
9.3.1.1 Position Capability Transfer. 444
9.3.1.2 LPP Abort . 464
9.3.2 LPP Transport . 471
9.3.2.1 LPP Duplicated Message . 471
9.3.2.2 LPP Acknowledgment . 475
9.3.2.3 LPP Retransmission . 478
9.3.3 LPP Error Handling . 482
ETSI
3GPP TS 37.571-2 version 18.5.0 Release 18 7 ETSI TS 137 571-2 V18.5.0 (2026-04)
9.3.3.1 Void. 482
9.3.3.1A Void. 482
9.3.3.1B LPP Requested Method not Supported – UE-Assisted . 482
9.3.4 LPP Positioning Procedures . 490
9.3.4.1 E-SMLC Initiated Assistance Data Delivery followed by Location Information Transfer: UE-
Based . 490
9.3.4.2 E-SMLC Initiated Assistance Data Delivery followed by Location Information Transfer:
UE-Assisted . 496
9.3.4.3 E-SMLC Initiated Position Measurement without assistance data: UE-Based . 502
9.3.4.4 E-SMLC Initiated Position Measurement without assistance data: UE-Assisted . 510
9.3.4.5 LPP carrier phase positioning procedure . 519
9.3.4.5.1 Test Purpose (TP) . 519
9.3.4.5.2 Conformance requirements . 519
9.3.4.5.3 Test description . 521
9.3.4.5.3.1 Pre-test conditions . 521
9.3.4.5.3.2 Test procedure sequence . 521
9.3.4.5.3.3 Specific message contents . 522
9.3.4.6 LPP frequency hopping positioning procedure for Redcap UEs . 530
9.3.4.6.1 Test Purpose (TP) . 530
9.3.4.6.2 Conformance requirements . 530
9.3.4.6.3 Test description . 532
9.3.4.6.3.1 Pre-test conditions . 532
9.3.4.6.3.2 Test procedure sequence . 532
9.3.4.6.3.3 Specific message contents . 533
9.3.4.7 PRS aggregation positioning procedure . 544
9.3.4.7.1 Test Purpose (TP) . 544
9.3.4.7.2 Conformance requirements . 544
9.3.4.7.3 Test description . 545
9.3.4.7.3.1 Pre-test conditions . 545
9.3.4.7.3.2 Test procedure sequence .
...