Content for TS 38.300 Word version: 18.0.0

1… 4… 4.7… 5… 5.3… 5.4… 6… 6.2… 6.6… 7… 8… 9… 9.2.2… 9.2.2.5… 9.2.3… 9.2.3.2… 9.2.3.3… 9.2.4… 9.2.6… 9.3… 10… 11… 15… 15.5… 16… 16.2… 16.3… 16.4… 16.8… 16.9… 16.10… 16.12… 16.12.5… 16.12.6… 16.12.6.3 16.12.7 16.13… 16.14… 16.15… 16.18… 16.19… 16.21… 16.21.3… 17… 18… 19 20… 21… A… B… C… G…

3.1 Abbreviations 3.2 Definitions
...

1 Scope p. 14

The present document provides an overview and overall description of the NG-RAN and focuses on the radio interface protocol architecture of NR connected to 5GC (E-UTRA connected to 5GC is covered in the 36 series). Details of the radio interface protocols are specified in companion specifications of the 38 series.

2 References p. 14

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific.
For a specific reference, subsequent revisions do not apply.
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.

[1]

TR 21.905: "Vocabulary for 3GPP Specifications".

[2]

TS 36.300: "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2".

[3]

TS 23.501: "System Architecture for the 5G System; Stage 2".

[4]

TS 38.401: "NG-RAN; Architecture description".

[5]

TS 33.501: "Security Architecture and Procedures for 5G System".

[6]

TS 38.321: "NR; Medium Access Control (MAC) protocol specification".

[7]

TS 38.322: "NR; Radio Link Control (RLC) protocol specification".

[8]

TS 38.323: "NR; Packet Data Convergence Protocol (PDCP) specification".

[9]

TS 37.324: " E-UTRA and NR; Service Data Protocol (SDAP) specification".

[10]

TS 38.304: "NR; User Equipment (UE) procedures in Idle mode and RRC Inactive state".

[11]

TS 38.306: "NR; User Equipment (UE) radio access capabilities".

[12]

TS 38.331: "NR; Radio Resource Control (RRC); Protocol specification".

[13]

TS 38.133: "NR; Requirements for support of radio resource management".

[14]

TS 22.168: "Earthquake and Tsunami Warning System (ETWS) requirements; Stage 1".

[15]

TS 22.268: "Public Warning System (PWS) Requirements".

[16]

TS 38.410: "NG-RAN; NG general aspects and principles".

[17]

TS 38.420: "NG-RAN; Xn general aspects and principles".

[18]

TS 38.101-1: "NR; User Equipment (UE) radio transmission and reception; Part 1: Range 1 Standalone".

[19]

TS 22.261: "Service requirements for next generation new services and markets".

[20]

TS 38.202: "NR; Physical layer services provided by the physical layer"

[21]

TS 37.340: "NR; Multi-connectivity; Overall description; Stage-2".

[22]

TS 23.502: "Procedures for the 5G System; Stage 2".

[23]

RFC 4960 (2007-09): "Stream Control Transmission Protocol".

[24]

TS 26.114: "Technical Specification Group Services and System Aspects; IP Multimedia Subsystem (IMS); Multimedia Telephony; Media handling and interaction".

[25] Void.

[26]

TS 38.413: "NG-RAN; NG Application Protocol (NGAP)".

[27]

RFC 3168 (09/2001): "The Addition of Explicit Congestion Notification (ECN) to IP".

[28]

TS 24.501: "NR; Non-Access-Stratum (NAS) protocol for 5G System (5GS)".

[29]

TS 36.331: "Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification".

[30]

TS 38.415: "NG-RAN; PDU Session User Plane Protocol".

[31]

TS 38.340: "NR; Backhaul Adaptation Protocol (BAP) specification".

[32]

TS 38.470: "NG-RAN; F1 application protocol (F1AP) ".

[33]

TS 38.425: "NG-RAN; NR user plane protocol".

[34]

TS 23.216: "Single Radio Voice Call Continuity (SRVCC); Stage 2".

[35]

TS 38.101-2: "User Equipment (UE) radio transmission and reception; Part 2: Range 2 Standalone".

[36]

TS 38.101-3: "User Equipment (UE) radio transmission and reception; Part 3: Range 1 and Range 2 Interworking operation with other radios".

[37]

TS 37.213: "Physical layer procedures for shared spectrum channel access".

[38]

TS 38.213: "NR; Physical layer procedures for control".

[39]

TS 22.104: "Service requirements for cyber-physical control applications in vertical domains".

[40]

TS 23.287: "Architecture enhancements for 5G System (5GS) to support Vehicle-to-Everything (V2X) services".

[41]

TS 23.285: "Technical Specification Group Services and System Aspects; Architecture enhancements for V2X services".

[42]

TS 38.305: "NG Radio Access Network (NG-RAN); Stage 2 functional specification of User Equipment (UE) positioning in NG-RAN".

[43]

TS 37.355: "LTE Positioning Protocol (LPP)".

[44]

TS 29.002: "Mobile Application Part (MAP) specification".

[45]

TS 23.247: "Architectural enhancements for 5G multicast-broadcast services; Stage 2".

[46]

TS 26.346: "Multimedia Broadcast/Multicast Service (MBMS); Protocols and codecs".

[47]

TS 23.122: "Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode".

[48]

TS 23.304: "Proximity based Services (ProSe) in the 5G System (5GS)".

[49]

TS 28.541: "5G Network Resource Model (NRM)".

[50]

TS 38.423: "NG-RAN; Xn Application Protocol (XnAP)".

[51]

NIMA TR 8350.2, Third Edition, Amendment 1, 3 January 2000: "DEPARTMENT OF DEFENSE WORLD GEODETIC SYSTEM 1984".

[52]

TS 38.211: "NR; Physical channels and modulation".

[53]

TS 24.587: "Vehicle-to-Everything (V2X) services in 5G System (5GS)".

[54]

TS 23.041: "Technical realization of Cell Broadcast Service (CBS)".

[55]

TS 24.554: "Technical Specification Group Core Network and Terminals; Proximity-services (ProSe) in 5G System (5GS) protocol".

[56]

TS 38.214: "Technical Specification Group Radio Access Network; NR; Physical layer procedures for data".

[57]

TR 38.835: "NR; Study on XR enhancements for NR".

[58]

TS 26.522: "5G Real-time Media Transport Protocol Configurations".
→ to date, still a draft

[59]

TS 38.215: "NR; Physical layer measurements".

[60]

TS 23.256: "Support of Uncrewed Aerial Systems (UAS) connectivity, identification and tracking; Stage 2".

3 Abbreviations and Definitions p. 16

3.1 Abbreviations p. 16

For the purposes of the present document, the abbreviations given in TR 21.905, in TS 36.300 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 and TS 36.300.

5GC

5G Core Network

5GS

5G System

5QI

5G QoS Identifier

A2X

Aircraft-to-Everything

A-CSI

Aperiodic CSI

AGC

Automatic Gain Control

Artificial Intelligence

AKA

Authentication and Key Agreement

AMBR

Aggregate Maximum Bit Rate

AMC

Adaptive Modulation and Coding

AMF

Access and Mobility Management Function

Augmented Reality

ARP

Allocation and Retention Priority

ATG

Air to Ground

Bandwidth Adaptation

BCCH

Broadcast Control Channel

BCH

Broadcast Channel

BFD

Beam Failure Detection

Backhaul

Bandwidth reduced Low complexity

BPSK

Binary Phase Shift Keying

BRID

Broadcast Remote Identification

C-RNTI

Cell RNTI

CAG

Closed Access Group

CAPC

Channel Access Priority Class

CBRA

Contention Based Random Access

CCE

Control Channel Element

CD-SSB

Cell Defining SSB

CFR

Common Frequency Resource

CFRA

Contention Free Random Access

Configured Grant

CHO

Conditional Handover

CIoT

Cellular Internet of Things

CLI

Cross Link interference

CMAS

Commercial Mobile Alert Service

CORESET

Control Resource Set

Cyclic Prefix

CPA

Conditional PSCell Addition

CPC

Conditional PSCell Change

DAA

Detect And Avoid

DAG

Directed Acyclic Graph

DAPS

Dual Active Protocol Stack

DFT

Discrete Fourier Transform

DCI

Downlink Control Information

DCP

DCI with CRC scrambled by PS-RNTI

DCR

Direct Communication Request

DL-AoD

Downlink Angle-of-Departure

DL-SCH

Downlink Shared Channel

DL-TDOA

Downlink Time Difference Of Arrival

DMRS

Demodulation Reference Signal

DRX

Discontinuous Reception

DSR

Delay Status Report

DTX

Discontinuous Transmission

E-CID

Enhanced Cell-ID (positioning method)

Energy Cost

EHC

Ethernet Header Compression

ePWS

enhancements of Public Warning System

ETWS

Earthquake and Tsunami Warning System

FSA ID

Frequency Selection Area Identity

G-CS-RNTI

Group Configured Scheduling RNTI

G-RNTI

Group RNTI

Feature Set

GFBR

Guaranteed Flow Bit Rate

GIN

Group ID for Network selection

GNSS

Global Navigation Satellite System

GSO

Geosynchronous Orbit

H-SFN

Hyper System Frame Number

HAPS

High Altitude Platform Station

HRNN

Human-Readable Network Name

IAB

Integrated Access and Backhaul

IFRI

Intra Frequency Reselection Indication

I-RNTI

Inactive RNTI

INT-RNTI

Interruption RNTI

KPAS

Korean Public Alarm System

Layer-2

Layer-3

LDPC

Low Density Parity Check

LEO

Low Earth Orbit

LTM

L1/L2 Triggered Mobility

MBS

Multicast/Broadcast Services

MCE

Measurement Collection Entity

MCCH

MBS Control Channel

MDBV

Maximum Data Burst Volume

MEO

Medium Earth Orbit

MIB

Master Information Block

MICO

Mobile Initiated Connection Only

MFBR

Maximum Flow Bit Rate

Machine Learning

MMTEL

Multimedia telephony

MNO

Mobile Network Operator

MO-SDT

Mobile Originated SDT

Multi-Path

MPE

Maximum Permissible Exposure

MRB

MBS Radio Bearer

Mobile Termination

MT-SDT

Mobile Terminated SDT

MTCH

MBS Traffic Channel

MTSI

Multimedia Telephony Service for IMS

MU-MIMO

Multi User MIMO

Multi-RTT

Multi-Round Trip Time

MUSIM

Multi-Universal Subscriber Identity Module

N3C

Non-3GPP Connection

NB-IoT

Narrow Band Internet of Things

NCD-SSB

Non Cell Defining SSB

NCGI

NR Cell Global Identifier

NCL

Neighbour Cell List

NCR

Neighbour Cell Relation

NCRT

Neighbour Cell Relation Table

NGAP

NG Application Protocol

NGSO

Non-Geosynchronous Orbit

NID

Network Identifier

NPN

Non-Public Network

NR Radio Access

NSAG

Network Slice AS Group

NTN

Non-Terrestrial Network

P-MPR

Power Management Maximum Power Reduction

P-RNTI

Paging RNTI

PCH

Paging Channel

PCI

Physical Cell Identifier

PDB

Packet Delay Budget

PDC

Propagation Delay Compensation

PDCCH

Physical Downlink Control Channel

PDSCH

Physical Downlink Shared Channel

PEI

Paging Early Indication

PER

Packet Error Rate

Paging Hyperframe

PLMN

Public Land Mobile Network

PNI-NPN

Public Network Integrated NPN

Paging Occasion

PQI

PC5 5QI

PRACH

Physical Random Access Channel

PRB

Physical Resource Block

PRG

Precoding Resource block Group

PRS

Positioning Reference Signal

PS-RNTI

Power Saving RNTI

PSDB

PDU Set Delay Budget

PSER

PDU Set Error Rate

PSI

PDU Set Importance

PSIHI

PDU Set Integrated Handling Information

PSS

Primary Synchronisation Signal

PTM

Point to Multipoint

PTP

Point to Point

PTW

Paging Time Window

PUCCH

Physical Uplink Control Channel

PUSCH

Physical Uplink Shared Channel

PWS

Public Warning System

QAM

Quadrature Amplitude Modulation

QFI

QoS Flow ID

QMC

QoE Measurement Collection

QoE

Quality of Experience

QPSK

Quadrature Phase Shift Keying

Random Access

RA-RNTI

Random Access RNTI

RACH

Random Access Channel

RANAC

RAN-based Notification Area Code

REG

Resource Element Group

RIM

Remote Interference Management

RLM

Radio Link Monitoring

RMSI

Remaining Minimum SI

RNA

RAN-based Notification Area

RNAU

RAN-based Notification Area Update

RNTI

Radio Network Temporary Identifier

RQA

Reflective QoS Attribute

RQoS

Reflective Quality of Service

Reference Signal

RSRP

Reference Signal Received Power

RSRQ

Reference Signal Received Quality

RSSI

Received Signal Strength Indicator

RSTD

Reference Signal Time Difference

RTT

Round Trip Time

RVQoE

RAN visible QoE

SCS

SubCarrier Spacing

Slice Differentiator

SDAP

Service Data Adaptation Protocol

SDT

Small Data Transmission

SL-PRS

Sidelink Positioning Reference Signal

SD-RSRP

Sidelink Discovery RSRP

SFI-RNTI

Slot Format Indication RNTI

SHR

Successful Handover Report

SIB

System Information Block

SI-RNTI

System Information RNTI

SLA

Service Level Agreement

SL-RSRP

Sidelink RSRP

SMC

Security Mode Command

SMF

Session Management Function

SMTC

SS/PBCH block Measurement Timing Configuration

S-NSSAI

Single Network Slice Selection Assistance Information

SNPN

Stand-alone Non-Public Network

SNPN ID

Stand-alone Non-Public Network Identity

SPR

Successful PSCell Addition/Change Report

SPS

Semi-Persistent Scheduling

Scheduling Request

SRAP

Sidelink Relay Adaptation Protocol

SRS

Sounding Reference Signal

SRVCC

Single Radio Voice Call Continuity

Synchronization Signal

SSB

SS/PBCH block

SSS

Secondary Synchronisation Signal

SSSG

Search Space Set Group

SST

Slice/Service Type

SU-MIMO

Single User MIMO

SUL

Supplementary Uplink

Timing Advance

Transport Block

TCE

Trace Collection Entity

TNL

Transport Network Layer

TPC

Transmit Power Control

TRP

Transmit/Receive Point

TRS

Tracking Reference Signal

U2N

UE-to-Network

U2U

UE-to-UE

UAV

Uncrewed Aerial Vehicle

UCI

Uplink Control Information

UDC

Uplink Data Compression

UDM

Unified Data Management

UE-Slice-MBR

UE Slice Maximum Bit Rate

UL-AoA

Uplink Angles of Arrival

UL-RTOA

Uplink Relative Time of Arrival

UL-SCH

Uplink Shared Channel

UPF

User Plane Function

URLLC

Ultra-Reliable and Low Latency Communications

Virtual Reality

V2X

Vehicle-to-Everything

Xn-C

Xn-Control plane

Xn-U

Xn-User plane

XnAP

Xn Application Protocol

eXtended Reality

3.2 Definitions p. 20

For the purposes of the present document, the terms and definitions given in TR 21.905, in TS 36.300 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 and TS 36.300.

A2X communication:

A communication to support A2X services leveraging PC5 reference points. A2X services are realized by various types of A2X applications, i.e. BRID or DAA.

Aerial UE communication:

functionality enabling Aerial UE function, as defined in 16.18.

Air to Ground network:

An NG-RAN consisting of ground-based gNBs, which provide cell towers that send signals up to an aircraft's antenna(s) of onboard ATG terminal, with typical vertical altitude of around 10,000m and take-off/landing altitudes down to 3000m.

BH RLC channel:

an RLC channel between two nodes, which is used to transport backhaul packets.

Boundary IAB-node:

as defined in TS 38.401.

Broadcast MRB:

A radio bearer configured for MBS broadcast delivery.

CAG Cell:

a PLMN cell broadcasting at least one Closed Access Group identity.

CAG Member Cell:

for a UE, a CAG cell broadcasting the identity of the selected PLMN, registered PLMN or equivalent PLMN, and for that PLMN, a CAG identifier belonging to the Allowed CAG list of the UE for that PLMN.

CAG-only cell:

a CAG cell that is only available for normal service for CAG UEs.

Cell-Defining SSB:

an SSB with an RMSI associated.

Child node:

IAB-DU's and IAB-donor-DU's next hop neighbour node; the child node is also an IAB-node.

Conditional Handover (CHO):

a handover procedure that is executed only when execution condition(s) are met.

CORESET#0:

the control resource set for at least SIB1 scheduling, can be configured either via MIB or via dedicated RRC signalling.

DAPS Handover:

a handover procedure that maintains the source gNB connection after reception of RRC message for handover and until releasing the source cell after successful random access to the target gNB.

Data Burst:

A set of multiple PDUs generated and sent by the application in a short period of time, as defined in TS 23.501.

Direct Path:

a type of UE-to-Network transmission path, where data is transmitted between a UE and the network without sidelink relaying.

Downstream:

direction toward child node or UE in IAB-topology.

Early Data Forwarding:

data forwarding that is initiated before the UE executes the handover.

Earth-centered, earth-fixed:

a global geodetic reference system for the Earth intended for practical applications of mapping, charting, geopositioning and navigation, as specified in NIMA TR 8350.2 [51].

eRedCap UE:

a UE with enhanced reduced capabilities as specified in clause 4.2.22.1 in TS 38.306.

Feeder link:

wireless link between the NTN Gateway and the NTN payload.

Geosynchronous Orbit:

earth-centered orbit at approximately 35786 kilometres above Earth's surface and synchronised with Earth's rotation. A geostationary orbit is a non-inclined geosynchronous orbit, i.e. in the Earth's equator plane.

Group ID for Network Selection:

an identifier used during SNPN selection to enhance the likelihood of selecting a preferred SNPN that supports a Default Credentials Server or a Credentials Holder, as specified in TS 23.501.

gNB:

node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC.

High Altitude Platform Station:

airborne vehicle embarking the NTN payload placed at an altitude between 8 and 50 km.

IAB-donor:

gNB that provides network access to UEs via a network of backhaul and access links.

IAB-donor-CU:

as defined in TS 38.401.

IAB-donor-DU:

as defined in TS 38.401.

IAB-DU:

gNB-DU functionality supported by the IAB-node to terminate the NR access interface to UEs and next-hop IAB-nodes, and to terminate the F1 protocol to the gNB-CU functionality, as defined in TS 38.401, on the IAB-donor.

IAB-MT:

IAB-node function that terminates the Uu interface to the parent node using the procedures and behaviours specified for UEs unless stated otherwise. IAB-MT function used in 38-series of 3GPP Specifications corresponds to IAB-UE function defined in TS 23.501.

IAB-node:

RAN node that supports NR access links to UEs and NR backhaul links to parent nodes and child nodes. The IAB-node does not support backhauling via LTE.

IAB topology:

the unison of all IAB-nodes and IAB-donor-DUs whose F1 and/or RRC connections are terminated at the same IAB-donor-CU.

Indirect Path:

a type of UE-to-Network transmission path, where data is forwarded via a U2N Relay UE between a U2N Remote UE and the network.

Inter-donor partial migration:

migration of an IAB-MT to a parent node underneath a different IAB-donor-CU while the collocated IAB-DU and its descendant IAB-node(s), if any, are terminated at the initial IAB-donor-CU. The procedure renders the said IAB-node as a boundary IAB-node.

Intra-system Handover:

handover that does not involve a CN change (EPC or 5GC).

Inter-system Handover:

handover that involves a CN change (EPC or 5GC).

Late Data Forwarding:

data forwarding that is initiated after the source NG-RAN node knows that the UE has successfully accessed a target NG-RAN node.

L1/L2 Triggered Mobility:

a cell switch procedure that the network triggers via MAC CE based on L1 measurements.

Mapped Cell ID:

in NTN, it corresponds to a fixed geographical area.

MBS Radio Bearer:

A radio bearer configured for MBS delivery.

Mobile-IAB cell:

a cell of a mobile IAB-DU.

Mobile IAB-DU:

gNB-DU functionality supported by the mobile IAB-node to terminate the NR access interface to UEs, and to terminate the F1 protocol to the gNB-CU functionality on the IAB-donor, as defined in TS 38.401.

Mobile IAB-DU migration:

procedure for a mobile IAB-node as defined in TS 38.401.

Mobile IAB-MT:

mobile IAB-node function that terminates the Uu interface to the parent node using the procedures and behaviours specified for UEs unless stated otherwise.

Mobile IAB-MT migration:

procedure for a mobile IAB-MT as defined in TS 38.401.

Mobile IAB-node:

RAN node that supports NR access links to UEs and an NR backhaul link to a parent node, and that can conduct physical mobility across the RAN area. The mobile IAB-node function used in 38-series of 3GPP Specifications corresponds to the MBSR function defined in TS 23.501.

MP Relay UE:

a UE that provides functionality to support connectivity to the network for MP Remote UE(s).

MP Remote UE:

a UE that communicates with the network via a direct Uu link and a MP Relay UE.

MSG1:

preamble transmission of the random access procedure for 4-step random access (RA) type.

MSG3:

first scheduled transmission of the random access procedure.

MSGA:

preamble and payload transmissions of the random access procedure for 2-step RA type.

MSGB:

response to MSGA in the 2-step random access procedure. MSGB may consist of response(s) for contention resolution, fallback indication(s), and backoff indication.

Multicast/Broadcast Service:

A point-to-multipoint service as defined in TS 23.247.

Multicast MRB:

A radio bearer configured for MBS multicast delivery.

Multi-hop backhauling:

using a chain of NR backhaul links between an IAB-node and an IAB-donor.

NCR-Fwd:

Network-Controlled Repeater node function, which performs amplifying-and-forwarding of UL/DL RF signals between gNB and UE. The behaviour of the NCR-Fwd is controlled according to the side control information received by the NCR-MT from a gNB.

NCR-Fwd access link:

link used for transmissions between the NCR-Fwd and UEs.

NCR-Fwd backhaul link:

link used for backhauling between the NCR-Fwd and gNB.

NCR-MT:

NCR-node entity which communicates with a gNB via a control link to receive side control information. The control link is based on NR Uu interface.

NCR-node:

RAN node comprising NCR-MT and NCR-Fwd.

ng-eNB:

node providing E-UTRA user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC.

NG-C:

control plane interface between NG-RAN and 5GC.

NG-U:

user plane interface between NG-RAN and 5GC.

NG-RAN node:

either a gNB or an ng-eNB.

Non-CAG Cell:

a PLMN cell which does not broadcast any Closed Access Group identity.

Non-Cell Defining SSB:

an SSB without an RMSI associated.

Non-Geosynchronous orbit:

earth-centered orbit with an orbital period that does not match Earth's rotation on its axis. This includes Low and Medium Earth Orbit (LEO and MEO). LEO operates at altitudes between 300 km and 1500 km and MEO at altitudes between 7000 km and 25000 km, approximately.

Non-terrestrial network:

an NG-RAN consisting of gNBs, which provide non-terrestrial NR access to UEs by means of an NTN payload embarked on an airborne or space-borne NTN vehicle and an NTN Gateway.

NR backhaul link:

NR link used for backhauling between an IAB-node and an IAB-donor, and between IAB-nodes in case of a multi-hop backhauling.

NR sidelink communication:

AS functionality enabling at least V2X communication as defined in TS 23.287 and the ProSe communication (including ProSe non-Relay and UE-to-Network Relay communication) as defined in TS 23.304, between two or more nearby UEs, using NR technology but not traversing any network node.

NR sidelink discovery:

AS functionality enabling ProSe non-Relay Discovery and ProSe UE-to-Network Relay discovery for Proximity based Services as defined in TS 23.304 between two or more nearby UEs, using NR technology but not traversing any network node.

NTN Gateway:

an earth station located at the surface of the earth, providing connectivity to the NTN payload using the feeder link. An NTN Gateway is a TNL node.

NTN payload:

a network node, embarked on board a satellite or high altitude platform station, providing connectivity functions, between the service link and the feeder link. In the current version of this specification, the NTN payload is a TNL node.

Numerology:

corresponds to one subcarrier spacing in the frequency domain. By scaling a reference subcarrier spacing by an integer N, different numerologies can be defined.

Parent node:

IAB-MT's next hop neighbour node; the parent node can be IAB-node or IAB-donor-DU.

PC5 Relay RLC channel:

an RLC channel between L2 U2N Remote UE and L2 U2N Relay UE, or between L2 U2U Remote UE and L2 U2U Relay UE, which is used to transport packets over PC5 for L2 UE-to-Network/UE-to-UE Relay.

PDU Set:

one or more PDUs carrying the payload of one unit of information generated at the application level (e.g. frame(s) or video slice(s) for XR Services), as defined in TS 23.501.

PLMN Cell:

a cell of the PLMN.

RACH-less LTM:

an LTM cell switch procedure where UE skips the random access procedure.

RedCap UE:

a UE with reduced capabilities as specified in clause 4.2.21.1 in TS 38.306.

Relay discovery:

AS functionality enabling 5G ProSe UE-to-Network Relay Discovery as defined in TS 23.304, using NR technology but not traversing any network node.

Satellite:

a space-borne vehicle orbiting the Earth embarking the NTN payload.

Service link:

wireless link between the NTN payload and UE.

Sidelink Discovery RSRP:

RSRP measurements on PC5 link related to NR sidelink discovery.

Sidelink RSRP:

RSRP measurements on PC5 link related to NR sidelink communication.

SNPN Access Mode:

mode of operation whereby a UE only accesses SNPNs.

SNPN-only cell:

a cell that is only available for normal service for SNPN subscribers.

SNPN Identity:

the identity of Stand-alone NPN defined by the pair (PLMN ID, NID).

Subsequent LTM:

LTM cell switch procedures between candidate cells without RRC reconfiguration by the network in between.

Transmit/Receive Point:

part of the gNB transmitting and receiving radio signals to/from UE according to physical layer properties and parameters inherent to that element.

U2N Relay UE:

a UE that provides functionality to support connectivity to the network for U2N Remote UE(s).

U2N Remote UE:

a UE that communicates with the network via a U2N Relay UE.

U2U Relay UE:

a UE that provides functionality to support connectivity between two U2U Remote UEs.

U2U Remote UE:

a UE that communicates with other UE(s) via a U2U Relay UE.

Upstream:

direction toward parent node in IAB-topology.

Uu Relay RLC channel:

an RLC channel between L2 U2N Relay UE and gNB, which is used to transport packets over Uu for L2 UE-to-Network Relay.

V2X sidelink communication:

AS functionality enabling V2X communication as defined in TS 23.285, between nearby UEs, using E-UTRA technology but not traversing any network node.

Xn:

network interface between NG-RAN nodes.