ETSI TS 138 300 V19.2.0 (2026-04)

5G; NR; NR and NG-RAN Overall description; Stage-2 (3GPP TS 38.300 version 19.2.0 Release 19)

RTS/TSGR-0238300vj20

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: 02-Apr-2026

Standards Content (Sample)

TECHNICAL SPECIFICATION
5G;
NR;
NR and NG-RAN Overall description;
Stage-2
(3GPP TS 38.300 version 19.2.0 Release 19)

3GPP TS 38.300 version 19.2.0 Release 19 1 ETSI TS 138 300 V19.2.0 (2026-04)

Reference
RTS/TSGR-0238300vj20
Keywords
5G
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ETSI
3GPP TS 38.300 version 19.2.0 Release 19 2 ETSI TS 138 300 V19.2.0 (2026-04)
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ETSI
3GPP TS 38.300 version 19.2.0 Release 19 3 ETSI TS 138 300 V19.2.0 (2026-04)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 14
1 Scope . 15
2 References . 15
3 Abbreviations and Definitions . 17
3.1 Abbreviations . 17
3.2 Definitions . 22
4 Overall Architecture and Functional Split . 27
4.1 Overall Architecture . 27
4.2 Functional Split . 28
4.3 Network Interfaces . 30
4.3.1 NG Interface . 30
4.3.1.1 NG User Plane . 30
4.3.1.2 NG Control Plane . 31
4.3.2 Xn Interface . 31
4.3.2.1 Xn User Plane . 31
4.3.2.2 Xn Control Plane . 32
4.4 Radio Protocol Architecture . 33
4.4.1 User Plane . 33
4.4.2 Control Plane . 33
4.5 Multi-Radio Dual Connectivity . 33
4.6 Radio Access Network Sharing . 34
4.7 Integrated Access and Backhaul . 34
4.7.1 Architecture . 34
4.7.2 Protocol Stacks . 35
4.7.3 User-plane Aspects . 36
4.7.3.1 Backhaul transport . 36
4.7.3.2 Flow and Congestion Control . 37
4.7.3.3 Uplink Scheduling Latency . 37
4.7.4 Signalling procedures . 37
4.7.4.1 IAB-node Integration . 37
4.7.4.2 IAB-node Migration . 38
4.7.4.3 Topological Redundancy . 38
4.7.4.4 Backhaul RLF Recovery . 38
4.7.4.5 OTA timing synchronization . 38
4.7.4.6 Inter node discovery . 39
4.7.5 Mobile IAB . 39
4.7.5.1 General . 39
4.7.5.2 Void. 39
4.8 Non-Public Networks . 39
4.9 Network-Controlled Repeaters . 40
4.9.1 Architecture . 40
4.9.2 Capabilities . 40
4.9.3 Signalling procedures . 40
4.9.4 OAM aspects . 41
4.9.5 Network-controlled repeater management . 41
4.10 Support of NR Femto nodes . 42
4.10.1 Architecture . 42
4.10.2 Functional Split . 43
4.10.2.1 NR Femto node . 43
4.10.2.2 AMF . 44
4.10.2.3 NR Femto GW . 44
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4.10.3 Interfaces. 45
4.10.3.1 Protocol Stack for NG User Plane . 45
4.10.3.2 Protocol Stacks for NG Control Plane . 46
4.10.4 Access Control . 46
4.11 Wireless Access Backhaul . 46
5 Physical Layer . 46
5.1 Waveform, numerology and frame structure . 46
5.2 Downlink . 47
5.2.1 Downlink transmission scheme . 47
5.2.2 Physical-layer processing for physical downlink shared channel . 48
5.2.3 Physical downlink control channels . 48
5.2.4 Synchronization signal and PBCH block . 49
5.2.5 Physical layer procedures . 50
5.2.5.1 Link adaptation . 50
5.2.5.2 Power Control . 50
5.2.5.3 Cell search . 50
5.2.5.4 HARQ . 51
5.2.5.5 Reception of SIB1 . 51
5.2.6 Downlink Reference Signals and Measurements for Positioning . 51
5.3 Uplink . 51
5.3.1 Uplink transmission scheme . 51
5.3.2 Physical-layer processing for physical uplink shared channel . 52
5.3.3 Physical uplink control channel . 52
5.3.4 Random access . 54
5.3.5 Physical layer procedures . 54
5.3.5.1 Link adaptation . 54
5.3.5.2 Uplink Power control . 54
5.3.5.3 Uplink timing control . 54
5.3.5.4 HARQ . 55
5.3.5.5 Prioritization of overlapping transmissions . 55
5.3.6 Uplink Reference Signals and Measurements for Positioning . 55
5.4 Carrier aggregation . 55
5.4.1 Carrier aggregation . 55
5.4.2 Supplementary Uplink . 56
5.4.3 Uplink Tx switching . 56
5.4.4 Low band carrier aggregation via switching . 56
5.5 Transport Channels. 56
5.6 Access to Shared Spectrum . 57
5.6.1 Overview . 57
5.6.2 Channel Access Priority Classes . 58
5.7 Sidelink . 58
5.7.1 General . 58
5.7.2 Sidelink resource allocation modes/schemes . 58
5.7.3 Physical sidelink channels and signals. 58
5.7.4 Physical layer procedures for sidelink . 59
5.7.4.1 HARQ feedback . 59
5.7.4.2 Power Control . 59
5.7.4.3 CSI report . 59
5.7.5 Physical layer measurement definition . 59
5.7.6 Sidelink Reference Signal and Measurements for Positioning . 59
6 Layer 2 . 60
6.1 Overview . 60
6.2 MAC Sublayer . 63
6.2.1 Services and Functions . 63
6.2.2 Logical Channels . 64
6.2.3 Mapping to Transport Channels. 64
6.2.4 HARQ . 64
6.3 RLC Sublayer . 64
6.3.1 Transmission Modes . 64
6.3.2 Services and Functions . 65
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6.3.3 ARQ . 65
6.4 PDCP Sublayer . 65
6.4.1 Services and Functions . 65
6.5 SDAP Sublayer . 66
6.6 L2 Data Flow . 66
6.7 Carrier Aggregation . 66
6.8 Dual Connectivity. 68
6.9 Supplementary Uplink . 68
6.10 Bandwidth Adaptation . 68
6.11 Backhaul Adaptation Protocol Sublayer . 69
6.11.1 Services and Functions . 69
6.11.2 Traffic Mapping from Upper Layers to Layer-2 . 69
6.11.3 Routing, BAP Header Rewriting and BH-RLC-channel Mapping on BAP sublayer . 70
6.12 Multiple Transmit/Receive Point Operation . 72
6.12.0 Overview . 72
6.12.1 Asymmetric DL single-TRP and UL multi-TRP . 73
7 RRC . 73
7.1 Services and Functions . 73
7.2 Protocol States . 73
7.3 System Information Handling . 74
7.3.1 Overview . 74
7.3.2 Scheduling . 77
7.3.3 SI Modification . 77
7.4 Access Control . 77
7.5 UE Capability Retrieval framework . 78
7.6 Transport of NAS Messages . 78
7.7 Carrier Aggregation . 78
7.8 Bandwidth Adaptation . 78
7.9 UE Assistance Information. 79
7.10 Segmentation of RRC messages . 80
8 NG Identities . 80
8.1 UE Identities . 80
8.2 Network Identities . 81
8.3 User Data Transport on the CN-RAN Interface . 82
8.4 NR sidelink communication, V2X sidelink communication and Ranging/Sidelink positioning related
identities . 82
9 Mobility and State Transitions . 83
9.1 Overview . 83
9.2 Intra-NR . 84
9.2.1 Mobility in RRC_IDLE . 84
9.2.1.1 Cell Selection . 84
9.2.1.2 Cell Reselection . 85
9.2.1.3 State Transitions . 85
9.2.2 Mobility in RRC_INACTIVE. 87
9.2.2.1 Overview . 87
9.2.2.2 Cell Reselection . 89
9.2.2.3 RAN-Based Notification Area . 89
9.2.2.4 State Transitions . 89
9.2.2.4.1 UE triggered transition from RRC_INACTIVE to RRC_CONNECTED . 89
9.2.2.4.2 Network triggered transition from RRC_INACTIVE to RRC_CONNECTED . 91
9.2.2.5 RNA update. 92
9.2.2.6 Resume request responded with Release with Redirect, with UE context relocation . 94
9.2.3 Mobility in RRC_CONNECTED . 95
9.2.3.1 Overview . 95
9.2.3.2 Handover . 97
9.2.3.2.1 C-Plane Handling . 97
9.2.3.2.2 U-Plane Handling . 101
9.2.3.2.3 Data Forwarding . 103
9.2.3.3 Re-establishment procedure . 104
9.2.3.4 Conditional Handover . 105
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9.2.3.4.1 General . 105
9.2.3.4.2 C-plane handling . 106
9.2.3.4.3 U-plane handling . 108
9.2.3.4.4 Data Forwarding . 108
9.2.3.5 L1/L2 Triggered Mobility . 108
9.2.3.5.1 General . 108
9.2.3.5.2 C-Plane Handling . 109
9.2.3.5.3 U-Plane Handling . 115
9.2.3.6 RACH-less handover . 115
9.2.3.7 Conditional L1/L2 Triggered Mobility . 115
9.2.3.7.1 General . 115
9.2.4 Measurements . 117
9.2.5 Paging . 121
9.2.6 Random Access Procedure . 124
9.2.7 Radio Link Failure . 127
9.2.8 Beam failure detection and recovery . 129
9.2.9 Timing Advance . 130
9.2.10 Extended DRX for RRC_IDLE and RRC_INACTIVE . 130
9.3 Inter RAT . 131
9.3.1 NR-E-UTRA mobility: Intra 5GC . 131
9.3.1.1 Cell Reselection . 131
9.3.1.2 Handover . 131
9.3.1.3 Measurements . 131
9.3.2 NR-E-UTRA mobility: From 5GC to EPC . 132
9.3.2.1 Cell Reselection . 132
9.3.2.2 Handover and redirection . 132
9.3.2.3 Measurements . 132
9.3.2.4 Data Forwarding for the Control Plane . 132
9.3.2.5 Data Forwarding for the User Plane . 133
9.3.3 NR-E-UTRA mobility: From EPC to 5GC . 133
9.3.3.1 Data Forwarding for the Control Plane . 133
9.3.3.2 Data Forwarding for the User Plane . 134
9.3.4 NR-UTRA mobility . 134
9.3.4.1 Handover with SRVCC operation . 134
9.3.4.2 Measurements . 135
9.4 Roaming and Access Restrictions . 135
10 Scheduling . 136
10.1 Basic Scheduler Operation . 136
10.2 Downlink Scheduling . 136
10.3 Uplink Scheduling . 137
10.4 Measurements to Support Scheduler Operation . 138
10.5 Rate Control . 138
10.5.1 Downlink . 138
10.5.2 Uplink . 138
10.6 Activation/Deactivation Mechanism . 139
10.7 E-UTRA-NR Cell Resource Coordination . 140
10.8 Cross Carrier Scheduling . 140
10.9 IAB Resource Configuration . 140
10.10 Autonomous Denial for IDC . 141
10.11 Multi-cell scheduling by a single DCI . 141
11 UE Power Saving . 141
12 QoS . 144
12.1 Overview . 144
12.2 Explicit Congestion Notification . 147
13 Security. 147
13.1 Overview and Principles . 147
13.2 Security Termination Points . 149
13.3 State Transitions and Mobility . 149
14 UE Capabilities . 150
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15 Self-Configuration and Self-Optimisation . 151
15.1 Definitions . 151
15.2 Void . 151
15.3 Self-configuration . 151
15.3.1 Dynamic configuration of the NG-C interface. 151
15.3.1.1 Prerequisites . 151
15.3.1.2 SCTP initialization .
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