ETSI TS 136 300 V17.12.0 (2026-02)

LTE; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (3GPP TS 36.300 version 17.12.0 Release 17)

RTS/TSGR-0236300vhc0

General Information

• Status: Not Published
• Technical Committee: 3GPP RAN 2 - Radio layer 2 specification and Radio layer 3 RR specification
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Completion Date: 26-Feb-2026

Standards Content (Sample)

TECHNICAL SPECIFICATION
LTE;
Evolved Universal Terrestrial Radio Access (E-UTRA)
and Evolved Universal Terrestrial
Radio Access Network (E-UTRAN);
Overall description;
Stage 2
(3GPP TS 36.300 version 17.12.0 Release 17)

3GPP TS 36.300 version 17.12.0 Release 17 1 ETSI TS 136 300 V17.12.0 (2026-02)

Reference
RTS/TSGR-0236300vhc0
Keywords
LTE
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 36.300 version 17.12.0 Release 17 2 ETSI TS 136 300 V17.12.0 (2026-02)
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 36.300 version 17.12.0 Release 17 3 ETSI TS 136 300 V17.12.0 (2026-02)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 19
1 Scope . 20
2 References . 20
3 Definitions, symbols and abbreviations . 24
3.1 Definitions . 24
3.2 Abbreviations . 27
4 Overall architecture . 33
4.0 General . 33
4.1 Functional Split . 33
4.2 Void . 36
4.2.1 Void . 36
4.2.2 Void . 36
4.3 Radio Protocol architecture . 36
4.3.0 General . 36
4.3.1 User plane . 36
4.3.2 Control plane . 36
4.4 Synchronization . 37
4.5 IP fragmentation . 37
4.6 Support of HeNBs . 37
4.6.1 Architecture . 37
4.6.2 Functional Split . 39
4.6.3 Interfaces. 41
4.6.3.1 Protocol Stack for S1 User Plane . 41
4.6.3.2 Protocol Stacks for S1 Control Plane . 42
4.6.3.3 Protocol Stack for S5 interface. 43
4.6.3.4 Protocol Stack for SGi interface . 43
4.6.3.5 Protocol Stack for X2 User Plane and X2 Control Plane . 43
4.6.4 Void . 43
4.6.5 Support of LIPA with HeNB . 43
4.6.6 Support of X2 GW . 45
4.6.6.1 Enhanced TNL Address Discovery . 46
4.6.6.2 Routing of X2AP messages . 46
4.6.6.3 (H)eNB unavailability . 46
4.6.6.4 (H)eNB registration . 46
4.7 Support for relaying. 46
4.7.1 General . 46
4.7.2 Architecture . 47
4.7.3 S1 and X2 user plane aspects . 47
4.7.4 S1 and X2 control plane aspects . 48
4.7.5 Radio protocol aspects . 49
4.7.6 Signalling procedures . 50
4.7.6.1 RN attach procedure . 50
4.7.6.2 E-RAB activation/modification. 51
4.7.6.3 RN startup procedure . 51
4.7.6.4 RN detach procedure . 52
4.7.6.5 Neighbouring Information Transfer . 53
4.7.6.6 Mobility to or from RN . 53
4.7.7 Relay Node OAM Aspects . 53
4.7.7.1 Architecture . 53
4.7.7.2 OAM Traffic QoS Requirements . 54
4.7.7.3 Security Aspects . 54
ETSI
3GPP TS 36.300 version 17.12.0 Release 17 4 ETSI TS 136 300 V17.12.0 (2026-02)
4.7.7.4 Void. 54
4.7.7.5 OAM Requirements for Configuration Parameters . 54
4.7.7.5.1 Parameters Associated with Relay Bearer Mapping . 54
4.8 Support of SIPTO at the Local Network . 54
4.8.1 General . 54
4.8.2 SIPTO at the Local Network with collocated L-GW . 55
4.8.3 Support for SIPTO@LN with Stand-Alone Gateway . 56
4.9 Support for Dual Connectivity . 56
4.9.1 General . 56
4.9.2 Radio Protocol Architecture . 56
4.9.3 Network Interfaces . 57
4.9.3.1 E-UTRAN Control Plane for Dual Connectivity . 57
4.9.3.2 E-UTRAN User Plane for Dual Connectivity . 57
4.9.3.3 Support of HeNBs for Dual Connectivity . 58
4.9.3.4 Support of SIPTO@LN and LIPA for Dual Connectivity . 58
4.10 NB-IoT . 60
4.11 Support for UE assistance information for local cache . 60
4.12 Support of Non-Terrestrial Networks . 60
5 Physical Layer for E-UTRA . 62
5.0 Frame structures and channels . 62
5.1 Downlink Transmission Scheme . 65
5.1.1 Basic transmission scheme based on OFDM . 65
5.1.1a Basic transmission scheme based on OFDM for NB-IoT . 66
5.1.2 Physical-layer processing . 66
5.1.3 Physical downlink control channels . 66
5.1.4 Downlink Reference signal and synchronization signals . 67
5.1.4a Downlink Reference signal and synchronization signals for NB-IoT . 68
5.1.5 Downlink multi-antenna transmission . 68
5.1.5a Downlink multi-antenna transmission for NB-IoT . 68
5.1.6 MBSFN transmission . 69
5.1.7 Physical layer procedure . 69
5.1.7.1 Link adaptation . 69
5.1.7.2 Power Control . 69
5.1.7.3 Cell search . 69
5.1.7.3a Cell search for NB-IoT . 69
5.1.8 Physical layer measurements definition . 69
5.1.9 Coordinated Multi-Point transmission . 70
5.1.10 Wake-up signal for NB-IoT . 70
5.1.11 Wake-up signal for BL UE or UE in enhanced coverage . 70
5.2 Uplink Transmission Scheme . 70
5.2.1 Basic transmission scheme . 70
5.2.1a Basic transmission scheme for NB-IoT . 71
5.2.2 Physical-layer processing . 71
5.2.3 Physical uplink control channel . 71
5.2.3a Uplink control information for NB-IoT . 72
5.2.4 Uplink Reference signal . 72
5.2.4a Uplink Reference signal for NB-IoT . 72
5.2.5 Random access preamble . 73
5.2.5a Random access preamble for NB-IoT . 73
5.2.6 Uplink multi-antenna transmission . 73
5.2.7 Physical channel procedure. 73
5.2.7.1 Link adaptation . 73
5.2.7.2 Uplink Power control . 74
5.2.7.3 Uplink timing control . 74
5.2.8 Coordinated Multi-Point reception . 74
5.3 Transport Channels. 74
5.3.0 Transport channel types . 74
5.3.1 Mapping between transport channels and physical channels . 76
5.3.1a Mapping between transport channels and narrowband physical channels . 76
5.4 E-UTRA physical layer model . 77
5.4.1 Void . 77
ETSI
3GPP TS 36.300 version 17.12.0 Release 17 5 ETSI TS 136 300 V17.12.0 (2026-02)
5.4.2 Void . 77
5.5 Carrier Aggregation . 77
5.5.0 General . 77
5.5.1 SRS switching between component carriers . 78
5.5a Multi-carrier operation for NB-IoT . 78
5.6 Sidelink . 79
5.6.0 General . 79
5.6.1 Basic transmission scheme . 79
5.6.2 Physical-layer processing . 79
5.6.3 Physical Sidelink control channel . 80
5.6.4 Sidelink reference signals . 80
5.6.5 Physical channel procedure. 80
5.6.5.1 Sidelink power control . 80
5.6.6 Physical layer measurements definition . 80
5.7 Licensed-Assisted Access . 80
5.7.0 General . 80
5.7.1 Channel Access Priority Classes . 81
5.7.2 Multiplexing of data. 81
5.8 Short Processing Time . 81
5.9 Short Transmission Time Interval . 82
6 Layer 2 . 82
6.0 Overview . 82
6.1 MAC Sublayer . 84
6.1.0 General . 84
6.1.1 Services and Functions . 84
6.1.2 Logical Channels . 85
6.1.2.0 General . 85
6.1.2.1 Control Channels . 85
6.1.2.2 Traffic Channels . 86
6.1.3 Mapping between logical channels and transport channels . 86
6.1.3.1 Mapping in Uplink . 86
6.1.3.2 Mapping in Downlink . 86
6.1.3.3 Mapping in Sidelink . 87
6.2 RLC Sublayer . 88
6.2.0 General . 88
6.2.1 Services and Functions . 88
6.2.2 PDU Structure . 88
6.3 PDCP Sublayer . 89
6.3.0 General . 89
6.3.1 Services and Functions . 89
6.3.2 PDU Structure . 90
6.4 Carrier Aggregation . 90
6.5 Dual Connectivity. 91
7 RRC . 93
7.0 General . 93
7.1 Services and Functions . 93
7.2 RRC protocol states & state transitions . 94
7.3 Transport of NAS messages . 95
7.3a CIoT signalling reduction optimisations . 95
7.3a.1 General . 95
7.3a.2 Control Plane CIoT EPS/5GS optimisation . 95
7.3a.3 User Plane CIoT EPS/5GS optimisations . 96
7.3b MO-EDT . 101
7.3b.1 General . 101
7.3b.2 MO-EDT for Control Plane CIoT EPS/5GS optimisations . 101
7.3b.3 MO-EDT for User Plane CIoT EPS/5GS optimisations . 103
7.3c MT-EDT . 108
7.3c.1 General . 108
7.3c.2 MT-EDT for Control Plane CIoT EPS Optimisation . 108
7.3c.3 MT-EDT for User Plane CIoT EPS Optimisation . 109
ETSI
3GPP TS 36.300 version 17.12.0 Release 17 6 ETSI TS 136 300 V17.12.0 (2026-02)
7.3d Transmission using PUR . 109
7.3d.1 General . 109
7.3d.2 PUR Configuration Request and PUR configuration . 110
7.3d.3 Transmission using PUR for Control Plane CIoT EPS/5GS Optimisations . 110
7.3d.4 Transmission using PUR for User Plane CIoT EPS/5GS Optimisations . 111
7.4 System Information . 113
7.5 Carrier Aggregation . 115
7.6 Dual Connectivity. 116
7.7 Segmentation of RRC messages . 117
8 E-UTRAN identities . 117
8.1 E-UTRA related UE identities . 117
8.2 Network entity related Identities . 118
8.3 Sidelink communication and V2X Sidelink Communication related identities . 119
8.4 MBMS related identities . 119
9 ARQ and HARQ . 120
9.0 General . 120
9.1 HARQ principles . 120
9.2 ARQ principles . 121
9.3 Void . 122
10 Mobility . 122
10.0 General . 122
10.1 Intra E-UTRAN . 122
10.1.0 General . 122
10.1.1 Mobility Management in ECM-IDLE . 123
10.1.1.1 Cell selection . 123
10.1.1.2 Cell reselection . 123
10.1.1.3 Void. 124
10.1.1.4 Void. 124
10.1.1.5 Void. 124
10.1.2 Mobility Management in ECM-CONNECTED/CM-CONNECTED . 124
10.1.2.0 General . 124
10.1.2.1 Handover . 125
10.1.2.1.0 General . 125
10.1.2.1.1 C-plane handling . 126
10.1.2.1.2 U-plane handling . 130
10.1.2.1a Conditional Handover . 132
10.1.2.1a.1 General . 132
10.1.2.1a.2 C-plane handling . 133
10.1.2.1a.3 U-plane handling . 134
10.1.2.1a.4 Data Forwarding . 134
10.1.2.2 Path Switch . 135
10.1.2.2.1 Path Switch upon handover . 135
10.1.2.2.2 Path Update upon Dual Connectivity specific acti vitie s . 135
10.1.2.2.3 Path Switch upon UE context resume . 135
10.1.2.3 Data forwarding . 135
10.1.2.3.1 For RLC-AM DRBs . 135
10.1.2.3.2 For RLC-UM DRBs . 136
10.1.2.3.3 SRB handling . 136
10.1.2.3.4 User data forwarding for Dual Connectivity . 137
10.1.2.3.5 For DRBs configured with DAPS Handover . 137
10.1.2.4 Void. 137
10.1.2.5 Void. 137
10.1.2.6 Void. 137
10.1.2.7 Timing Advance . 137
10.1.2.8 Dual Connectivity operation . 138
10.1.2.8.1 SeNB Addition . 138
10.1.2.8.2 SeNB Modification . 139
10.1.2.8.2.1 Intra-MeNB handover involving SCG change . 142
10.1.2.8.3 SeNB Release . 143
10.1.2.8.4 Change of SeNB . 144
ETSI
3GPP TS 36.300 version 17.12.0 Release 17 7 ETSI TS 136 300 V17.12.0 (2026-02)
10.1.2.8.5 MeNB to eNB Change . 146
10.1.2.8.6 SCG change . 147
10.1.2.8.7 eNB to MeNB change . 147
10.1.2.8.8 Inter-MeNB handover without SeNB change . 148
10.1.2.8.9 Addition of a hybrid HeNB as the SeNB . 151
10.1.2.9
...