ETSI TS 138 304 V17.11.0 (2026-04)

5G; NR; User Equipment (UE) procedures in Idle mode and in RRC Inactive state (3GPP TS 38.304 version 17.11.0 Release 17)

RTS/TSGR-0238304vhb0

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: 09-Apr-2026

Standards Content (Sample)

TECHNICAL SPECIFICATION
5G;
NR;
User Equipment (UE)
procedures in Idle mode and in RRC Inactive state
(3GPP TS 38.304 version 17.11.0 Release 17)

3GPP TS 38.304 version 17.11.0 Release 17 1 ETSI TS 138 304 V17.11.0 (2026-04)

Reference
RTS/TSGR-0238304vhb0
Keywords
5G
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ETSI
3GPP TS 38.304 version 17.11.0 Release 17 2 ETSI TS 138 304 V17.11.0 (2026-04)
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ETSI
3GPP TS 38.304 version 17.11.0 Release 17 3 ETSI TS 138 304 V17.11.0 (2026-04)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions, symbols and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 9
4 General description of RRC_IDLE state and RRC_INACTIVE state . 10
4.1 Overview . 10
4.2 Functional division between AS and NAS in RRC_IDLE state and RRC_INACTIVE state . 12
4.3 Service types in RRC_IDLE state . 15
4.4 Service types in RRC_INACTIVE state . 15
4.5 Cell Categories . 15
5 Process and procedure descriptions . 16
5.1 PLMN selection and SNPN selection . 16
5.1.1 Support for PLMN selection . 17
5.1.1.1 General . 17
5.1.1.2 NR case . 17
5.1.1.3 E-UTRA case . 17
5.1.2 Support for SNPN selection . 17
5.1.2.1 General . 17
5.1.2.2 NR case . 17
5.2 Cell selection and reselection . 18
5.2.1 Introduction. 18
5.2.2 States and state transitions in RRC_IDLE state and RRC_INACTIVE state . 19
5.2.3 Cell Selection process . 20
5.2.3.1 Description . 20
5.2.3.2 Cell Selection Criterion . 21
5.2.3.3 E-UTRAN case in Cell Selection . 22
5.2.4 Cell Reselection evaluation process . 22
5.2.4.1 Reselection priorities handling . 22
5.2.4.2 Measurement rules for cell re-selection . 24
5.2.4.3 Mobility states of a UE . 25
5.2.4.3.0 Introduction . 25
5.2.4.3.1 Scaling rules . 26
5.2.4.4 Cells with cell reservations, access restrictions or unsuitable for normal camping. 27
5.2.4.5 NR Inter-frequency and inter-RAT Cell Reselection criteria . 27
5.2.4.6 Intra-frequency and equal priority inter-frequency Cell Reselection criteria . 28
5.2.4.7 Cell reselection parameters in system information broadcasts . 29
5.2.4.7.0 General reselection parameters . 29
5.2.4.7.1 Speed dependent reselection parameters . 31
5.2.4.7.2 Slice-based cell reselection parameters . 32
5.2.4.8 Inter-RAT Cell reselection in RRC_INACTIVE state . 32
5.2.4.9 Relaxed measurement . 32
5.2.4.9.0 Relaxed measurement rules . 32
5.2.4.9.1 Relaxed measurement criterion for UE with low mobility . 34
5.2.4.9.2 Relaxed measurement criterion for UE not at cell edge . 34
5.2.4.9.3 Relaxed measurement criterion for a stationary RedCap UE . 34
5.2.4.9.4 Relaxed measurement criterion for a stationary RedCap UE not at cell edge . 35
5.2.4.10 Cell reselection with CAG cells . 35
5.2.4.11 Reselection priorities for slice-based cell reselection. 35
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5.2.5 Camped Normally state . 36
5.2.6 Selection of cell at transition to RRC_IDLE or RRC_INACTIVE state . 36
5.2.7 Any Cell Selection state . 37
5.2.8 Camped on Any Cell state . 37
5.3 Cell Reservations and Access Restrictions . 37
5.3.0 Introduction. 37
5.3.1 Cell status and cell reservations . 37
5.3.2 Unified access control . 40
5.4 Tracking Area registration . 40
5.5 RAN Area registration . 41
6 Reception of broadcast information . 41
6.1 Reception of system information . 41
6.2 Reception of MBS . 41
7 Paging . 41
7.1 Discontinuous Reception for paging . 41
7.2 Paging Early Indication . 44
7.2.1 Paging Early Indication reception . 44
7.3 Subgrouping . 45
7.3.0 General . 45
7.3.1 CN assigned subgrouping . 45
7.3.2 UE_ID based subgrouping . 45
7.4 Paging in extended DRX . 46
8 Sidelink Operation . 47
8.1 NR sidelink communication, and V2X sidelink communication, and NR sidelink discovery . 47
8.2 Cell selection and reselection for Sidelink . 47
8.2.1 Parameters used for cell selection and reselection triggered for sidelink . 48
9 Tracking Reference Signal . 48
Annex A (informative): Example of Hashed ID Calculation using 32-bit FCS . 49
Annex B (informative): Change history . 50
History . 54

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3GPP TS 38.304 version 17.11.0 Release 17 5 ETSI TS 138 304 V17.11.0 (2026-04)
Foreword
This Technical Specification has been produced by the 3rd Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
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3GPP TS 38.304 version 17.11.0 Release 17 6 ETSI TS 138 304 V17.11.0 (2026-04)
1 Scope
The present document specifies the Access Stratum (AS) part of the UE procedures in RRC_IDLE state (also called Idle
mode) and RRC_INACTIVE state. The non-access stratum (NAS) part of Idle mode procedures and processes is
specified in TS 23.122 [9].
The present document specifies the model for the functional division between the NAS and AS in a UE.
The present document applies to all UEs that support at least NR Radio Access, including multi-RAT UEs as described
in 3GPP specifications, in the following cases:
- When the UE is camped on a NR cell;
- When the UE is searching for a cell to camp on;
NOTE: When the UE is camped on or searching for a cell to camp on belonging to other RATs, the UE behaviour
is described in the specifications of the other RATs.
2 References
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] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 38.300: "NR Overall Description; Stage 2".
[3] 3GPP TS 38.331: "NR; Radio Resource Control (RRC) - Protocol Specification".
[4] 3GPP TS 38.213: "NR; Physical layer procedures for control ".
[5] Void
[6] 3GPP TS 36.331: "E-UTRA; Radio Resource Control (RRC) - Protocol Specification".
[7] 3GPP TS 36.304: "E-UTRA; User Equipment (UE) procedures in RRC_IDLE state ".
[8] 3GPP TS 38.133: "NR; Requirements for Support of Radio Resource Management".
[9] 3GPP TS 23.122: "NAS functions related to Mobile Station (MS) in RRC_IDLE state".
[10] 3GPP TS 23.501: "System Architecture for the 5G System; Stage 2".
[11] 3GPP TS 38.215: "NR; Physical layer measurements".
[12] 3GPP TS 22.261: "Service requirements for the 5G system".
[13] 3GPP TS 24.890: "5G System – Phase 1; CT WG1 Aspects".
[14] 3GPP TS 24.501: "Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3".
[15] 3GPP TS 38.101-1: "NR; User Equipment (UE) radio transmission and reception; Part 1: Range 1
Standalone".
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[16] 3GPP TS 23.287: "Architecture enhancements for 5G System (5GS) to support Vehicle-to-
Everything (V2X) services".
[17] 3GPP TS 23.285: "Technical Specification Group Services and System Aspects; Architecture
enhancements for V2X services".
[18] 3GPP TS 22.011: "Service accessibility".
[19] 3GPP TS 38.321: "NR; Medium Access Control (MAC); Protocol specification".
[20] 3GPP TS 26.517: "5G Multicast-Broadcast User Services; Protocols and Formats".
[21] 3GPP TS 23.247: "Architectural enhancements for 5G multicast-broadcast services; Stage 2".
[22] 3GPP TS 23.304: "Proximity based Services (ProSe) in 5G Systems (5GS)".
[23] 3GPP TS 23.003: "Numbering, addressing and identification".
[24] 3GPP TS 38.306: "User Equipment (UE) radio access capabilities".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Acceptable Cell: A cell that satisfies certain conditions as specified in 4.5.
Allowed CAG list: A per-PLMN list of CAG Identifiers the UE is allowed to access (see TS 23.501 [10]).
Available PLMN(s): One or more PLMN(s) for which the UE has found at least one cell and read its PLMN
identity(ies).
Available SNPN(s): One or more SNPN(s) for which the UE has found at least one cell and read its SNPN
identity(ies).
Barred Cell: A cell a UE is not allowed to camp on.
CAG cell: A cell broadcasting at least one Closed Access Group Identifier.
Camped on a cell: UE has completed the cell selection/reselection process and has chosen a cell. The UE monitors
system information and (in most cases) paging information.
Camped on any cell: UE is in idle mode and has completed the cell selection/reselection process and has chosen a cell
irrespective of PLMN identity.
Closed Access Group Identifier: Identifier of a CAG within a PLMN.
Commercial Mobile Alert System: Public Warning System that delivers Warning Notifications provided by Warning
Notification Providers to CMAS capable UEs.
eCall Only Mode: A UE configuration option that allows the UE to register at 5GC and register in IMS to perform only
eCall Over IMS, and a non-emergency IMS call for test and/or terminal reconfiguration services.
EHPLMN: Any of the PLMN entries contained in the Equivalent HPLMN list TS 23.122 [9].
Equivalent PLMN list: List of PLMNs considered as equivalent by the UE for cell selection, cell reselection, and
handover according to the information provided by the NAS.
Home PLMN: A PLMN where the Mobile Country Code (MCC) and Mobile Network Code (MNC) of the PLMN
identity are the same as the MCC and MNC of the IMSI.
HSDN cell: A cell that has higher priority than other cells for cell reselection for HSDN capable UE in a High-mobility
state.
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Network Identifier: Identifier of an SNPN in combination with a PLMN ID (TS 23.501 [10]).
Non-Public Network: A network deployed for non-public use, as defined in TS 22.261 [12].
Non-terrestrial network: An NG-RAN consisting of gNBs, which provides 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 sidelink communication: AS functionality enabling at least V2X Communication as defined in TS 23.287 [16],
and ProSe communication (including ProSe non-Relay and UE-to-Network Relay communication) as defined in TS
23.304 [22], 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 [22] between two or more nearby UEs, using NR
technology but not traversing any network node.
Process: A local action in the UE invoked by an RRC procedure or an RRC_IDLE or RRC_INACTIVE state
procedure.
Quasi-earth fixed cell: An NTN cell fixed with respect to a certain geographic area on the earth during a certain time
duration. This can be provisioned by beam(s) covering one geographic area for a limited period and a different
geographic area during another period (e.g., the case of NGSO satellites generating steerable beams).
Radio Access Technology: Type of technology used for radio access, for instance NR or E-UTRA.
RedCap UE: A UE with reduced capabilities as specified in clause 4.2.21 in TS 38.306 [24].
Registration Area: (NAS) registration area is an area in which the UE may roam without a need to perform location
registration, which is a NAS procedure.
Registered PLMN: This is the PLMN on which certain Location Registration outcomes have occurred, as specified in
TS 23.122 [9].
Registered SNPN: This is the SNPN on which certain Location Registration outcomes have occurred, as specified in
TS 23.122 [9].
Reserved Cell: A cell on which camping is not allowed, except for particular UEs, if so indicated in the system
information.
Selected PLMN: This is the PLMN that has been selected by the NAS, either manually or automatically.
Selected SNPN: This is the SNPN that has been selected by the NAS, either manually or automatically.
Serving cell: The cell on which the UE is camped.
Sidelink: UE to UE interface for V2X sidelink communication defined in TS 23.287[16].
SNPN Access Mode: Mode of operation wherein UE only selects SNPNs (as defined in TS 23.501 [10]).
SNPN identity: An identifier of an SNPN comprising of a PLMN ID and an NID combination.
Strongest cell: The cell on a particular frequency that is considered strongest according to the layer 1 cell search
procedure (TS 38.213 [4], TS 38.215 [11]).
Suitable Cell: This is a cell on which a UE may camp. For NR cell, the criteria are defined in clause 4.5, for E-UTRA
cell in TS 36.304 [7].
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.
V2X sidelink communication: AS functionality enabling V2X Communication as defined in TS 23.285 [17], between
nearby UEs, using E-UTRA technology but not traversing any network node.
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3.2 Abbreviations
For the purposes of the present document, the abbreviations given in TR 21.905 [1] 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 [1].
AS Access Stratum
CAG Closed Access Group
CAG-ID Closed Access Group Identifier
CMAS Commercial Mobile Alert System
CN Core Network
DCI Downlink Control Information
DRX Discontinuous Reception
eDRX Extended DRX
ETWS Earthquake and Tsunami Warning System
E-UTRA Evolved UMTS Terrestrial Radio Access
E-UTRAN Evolved UMTS Terrestrial Radio Access Network
GIN Group ID for Network selection
H-SFN Hyper System Frame Number
HRNN Human-Readable Network Name
HSDN High Speed Dedicated Network
IAB Integrated Access and Backhaul
IMSI International Mobile Subscriber Identity
L2 Layer-2
MBS Multicast/Broadcast Services
MBS FSAI MBS Frequency Selection Area Identity
MCC Mobile Country Code
MCCH MBS Control Channel
MICO Mobile Initiated Connection Only
MRB MBS Radio Bearer
MTCH MBS Traffic Channel
NAS Non-Access Stratum
NID Network Identifier
NPN Non-Public Network
NR NR Radio Access
NSAG Network Slice AS Group
NTN Non-Terrestrial Network
PEI Paging Early Indication
PEI-O Paging Early Indication-Occasion
PH Paging Hyperframe
PLMN Public Land Mobile Network
PTW Paging Time Window
RAT Radio Access Technology
RNA RAN-based Notification Area
RNAU RAN-based Notification Area Update
RRC Radio Resource Control
SDT Small Data Transmission
SL Sidelink
SNPN Stand-alone Non-Public Network
TRS Tracking Reference Signal
U2N UE-to-Network
UAC Unified Access Control
UE User Equipment
UMTS Universal Mobile Telecommunications System
V2X Vehicle to Everything
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4 General description of RRC_IDLE state and
RRC_INACTIVE state
4.1 Overview
The RRC_IDLE state and RRC_INACTIVE state tasks can be subdivided into three processes:
- PLMN selection (for UE not operating in SNPN access mode) or SNPN selection (for UE operating in SNPN
access mode);
- Cell selection and reselection;
- Location registration and RNA update.
PLMN selection, SNPN selection, cell reselection procedures, and location registration are common for both
RRC_IDLE state and RRC_INACTIVE state. RNA update is only applicable for RRC_INACTIVE state. When UE
selects a new PLMN or SNPN, UE transitions from RRC_INACTIVE to RRC_IDLE, as specified in TS 24.501 [14].
When a UE is switched on, a public land mobile network (PLMN) or a SNPN is selected by NAS. For the selected
PLMN/SNPN, associated RAT(s) may be set, as specified in TS 23.122 [9]. The NAS shall provide a list of equivalent
PLMNs, if available, that the AS shall use for cell selection and cell reselection.
With cell selection, the UE searches for a suitable cell of the selected PLMN or selected SNPN, chooses that cell to
provide available services, and monitors its control channel. This procedure is defined as "camping on the cell".
The UE shall, if necessary, then register its presence, by means of a NAS registration procedure, in the tracking area of
the chosen cell. As an outcome of a successful Location Registration, the selected PLMN/SNPN then becomes the
registered PLMN/SNPN, as specified in TS 23.122 [9].
If the UE finds a more suitable cell, according to the cell reselection criteria, it reselects onto that cell and camps on it.
If the new cell does not belong to at least one tracking area to which the UE is registered, location registration is
performed. In RRC_INACTIVE state, if the new cell does not belong to the configured RNA, an RNA update
procedure is performed.
If necessary, the UE shall search for higher priority PLMNs at regular time intervals as described in TS 23.122 [9] and
search for a suitable cell if another PLMN has been selected by NAS.
For UE not operating in SNPN access mode, search of available CAGs may be triggered by NAS to support manual
CAG selection. The AS shall report available CAG-ID(s) together with their HRNN (if broadcast) and PLMN(s) to the
NAS.
NAS may also provide the network slice(s) and Network Slice AS Group (NSAG) information, which contains
NSAG(s), their applicable TA(s) if present and their priorities, to be considered by the UE during cell reselection (as
specified in TS 23.501 [10], TS 24.501 [14]).
If the UE loses coverage of the registered PLMN/SNPN, either a new PLMN/SNPN is selected automatically
(automatic mode), or an indication of available PLMNs/SNPNs is given to the user so that a manual selection can be
performed (manual mode). As part of manual SNPN selection, the AS shall report available SNPN identifiers together
with their HRNN (if broadcast) to the NAS.
Registration is not performed by UEs only capable of services that need no registration.
The UE may perform NR sidelink communication and/or V2X sidelink communication while in-coverage or out-of-
coverage for sidelink, as specified in clause 8.
The U2N Remote UE, the U2N Relay UE, or both may perform sidelink discovery transmissions while in-coverage for
the purpose of sidelink relay operations, as specified in clause 8. In addition, the U2N Remote UE can also perform
sidelink discovery transmissions while out-of-coverage for the purpose of sidelink relay operations.
An L2 U2N Remote UE in RRC_IDLE or in RRC_INACTIVE may perform all the relevant procedures (e.g., acquiring
system information and paging message) via the L2 U2N Relay UE. An L2 U2N Remote UE may choose not to
perform any procedures related to cell selection and reselection.
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The UE may perform NR sidelink discovery transmissions while in-coverage or out-of-coverage for the purpose of
sidelink non-relay operations, as specified in clause 8.
The purpose of camping on a cell in RRC_IDLE state and RRC_INACTIVE state is as follows:
a) It enables the UE to receive system information from the PLMN or the SNPN.
b) When registered and if the UE wishes to establish an RRC connection or resume a suspended RRC connection, it
can do this by initially accessing the network on the control channel of the cell on which it is camped.
c) If the network needs to send a message or deliver data to the registered UE, it knows (in most cases) the set of
tracking areas (in RRC_IDLE state) or RNA (in RRC_INACTIVE state) in which the UE is camped. It can then
send a "paging" message for the UE on the control channels of all the cells in the corresponding set of areas. The
UE will then receive the paging message and can respond.
d) It enables the UE to receive ETWS and CMAS notifications.
e) It enables the UE to receive MBS broadcast services.
When the UE is in RRC_IDLE state, upper layers may deactivate AS layer when MICO mode is activated as specified
in TS 24.501 [14]. When MICO mode is activated, the AS configuration (e.g. priorities provided by dedicated
signalling) is kept and all running timers continue to run but the UE need not perform any idle mode tasks. If a timer
expires while MICO mode is activated it is up to the UE implementation whether it performs the corresponding action
immediately or the latest when MICO mode is deactivated. When MICO mode is deactivated, the UE shall perform all
idle mode tasks.
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4.2 Functional division between AS and NAS in RRC_IDLE
state and RRC_INACTIVE state
Table 4.2-1 presents the functional division between UE non-access stratum (NAS) and UE access stratum (AS) in
RRC_IDLE state and RRC_INACTIVE states. The NAS part is specified in TS 23.122 [9] and the AS part in the
present document.
Table 4.2-1: Functional division between AS and NAS in RRC_IDLE state and RRC_INACTIVE state
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RRC_IDLE and UE Non-Access Stratum UE Access Stratum
RRC_INACTIVE
state Process
For a UE not operating in SNPN access mode,
PLMN Selection For a UE not operating in SNPN access
and SNPN perform the following: mode, search for available PLMNs.
Selection Maintain a list of PLMNs in priority order according
to TS 23.122 [9]. Select a PLMN using automatic If associated RAT(s) is (are) set for the
or manual mode as specified in TS 23.122 [9] and PLMN, search in this (these) RAT(s) and
request AS to select a cell belonging to this other RAT(s) for that PLMN as specified in
PLMN. For each PLMN, associated RAT(s) may TS 23.122 [9].
be set.
For a UE operating in SNPN access mode,
Evaluate reports of available PLMNs and any search for available SNPNs only consider
associated CAG-IDs from AS for PLMN selection. NR cells.

Maintain a list of equivalent PLMN identities. Perform measurements to support
PLMN/SNPN selection.
Maintain a list of "PLMNs not allowed to operate at
the present UE location". Synchronise to a broadcast channel to
identify found PLMNs/SNPNs.
Maintain applicable disaster roaming information
for available PLMNs including potential disaster Report available PLMNs and any
PLMNs for available PLMNs. associated CAG-IDs with associated
RAT(s) to NAS on request from NAS or
To support manual CAG selection, provide autonomously.
request to search for available CAGs and evaluate
reports of available CAGs from AS for CAG Report applicable disaster roaming
selection. information for available PLMNs
autonomously including potential disaster
For a UE operating in SNPN access mode, PLMNs.
perform the following:
Maintain a list of SNPNs according to TS 23.122 For a UE operating in SNPN access mode,
[9]. Select a SNPN using automatic or manual report available SNPNs to NAS
mode as specified in TS 23.122 [9] and request autonomously; report information related to
AS to select a cell belonging to this SNPN.
SNPN access with subscription of a
different Credentials Holder, indicator
Evaluate reports of available SNPNs from AS for whether onboarding is enabled, and the list
SNPN selection. of supported GINs to NAS autonomously,
as specified in TS 38.331 [3].

To support manual CAG selection,
perform the following:
Search for cells broadcasting a CAG-ID.

Read the HRNN (if broadcast) for each
CAG-ID if a cell broadcasting a CAG-ID is
found.
Report CAG-ID(s) of found cell(s)
broadcasting a CAG-ID together with the
associated manual CAG selection allowed
indicator, HRNN and PLMNto NAS.

On selection of a CAG by NAS, select any
acceptable or suitable cell belonging to the
selected CAG and give an indication to
NAS that access is possible (for the
registration procedure)
To support manual SNPN selection, report
available SNPNs together with associated
HRNNs (if available) to NAS on request
from NAS.
ETSI
3GPP TS 38.304 version 17.11.0 Release 17 14 ETSI TS 138 304 V17.11.0 (2026-04)
RRC_IDLE and UE Non-Access Stratum UE Access Stratum
RRC_INACTIVE
state Process
Cell Control cell selection for example by indicating Perform measurements needed to support
Selection RAT(s) associated with the selected PLMN to be cell selection.
used initially in the search of a cell in the cell
selection. Detect and synchronise to a broadcast
channel. Receive and handle broadcast
Maintain a list of "Forbidden Tracking Areas" and information. Forward NAS system
provide the list to AS. information to NAS.

Maintain a list of "PLMNs not allowed to operate at Search for a suitable cell. The cells
the present UE location" and provide the list to AS. broadcast one or more 'PLMN identity' or
'SNPN identity' (for a UE operating in
For a UE not operating in SNPN access mode: SNPN access mode) in the system
Maintain Allowed CAG list and optional CAG-only information. Respond to NAS whether such
indication along with associated PLMN ID(s) on cell is found or not.
which the UE is allowed access and provide these
lists to AS. To support manual CAG selection, If associated RATs is (are) set for the
select a CAG and request AS to select a cell PLMN, perform the search in this (these)
belonging to this CAG. RAT(s) and other RATs for that PLMN as
specified in TS 23.122 [9].
If a cell is found which satisfies cell
selection criteria, camp on that cell.
Cell For a UE not operating in SNPN access mode, Perform measurements needed to support
Reselection maintain a list of equivalent PLMN identities and cell reselection.
provide the list to AS.
Detect and synchronise to a broadcast
Maintain a list of "Forbidden Tracking Areas" and channel. Receive and handle broadcast
provide the list to AS. information. Forward NAS system
information to NAS.
Maintain a list of "PLMNs not allowed to operate at
the present UE location" and provide the list to AS. Change cell if a more suitable cell is found.

For a UE not operating in SNPN access mode,
Derive cell reselection priorities for slice-
maintain Allowed CAG list and optional CAG-only based cell reselection.
indication along with associated PLMN ID(s) on
which the UE is allowed access and provide these
lists to AS.
Maintain the network slice(s) and NSAG
information and provide network slice(s) and
NSAG information to AS.
Location Register the UE as active after power on. Report registration area information to
registration NAS.
Register the UE's presence in a registration area,
for instance regularly or when entering a new
tracking area.
Deregister UE when shutting down.

Maintain a list of "Forbidden Tracking Areas".

Maintain a list of "PLMNs not allowed to operate at
the present UE location".
Control and restrict location registration for a UE in
eCall Only Mode.
ETSI
3GPP TS 38.304 version 17.11.0 Release 17 15 ETSI TS 138 304 V17.11.0 (2026-04)
RRC_IDLE and UE Non-Access Stratum UE Access Stratum
RRC_INACTIVE
state Process
RAN Notification Not applicable. Register the UE's presence in a RAN-
Area Update based notification area (RNA), periodically
or when entering a new RNA.
4.3 Service types in RRC_IDLE state
This clause defines the level of service that may be provided by the network to a UE in RRC_IDLE state. The following
three levels of services are provided while a UE is in RRC_IDLE state:
- Limited service (emergency calls, ETWS and CMAS on an acceptable cell);
- Normal service (for public use or non-public use on a suitable cell);
- Operator service (for operators only on a reserved cell).
4.4 Service types in RRC_INACTIVE state
This clause defines the level of service that may be provided by the network to a UE in RRC_INACTIVE state. The
following two levels of services are provided while a UE is in RRC_INACTIVE state:
- Normal service (for public use or non-public use on a suitable cell);
- Operator service (for operators only on a reserved cell).
4.5 Cell Categories
The cells are categorised according to which services they offer:
acceptable cell:
An "acceptable cell" is a cell on which the UE may camp to obtain limited service (originate emergency calls and
receive ETWS and CMAS notifications). Such a cell shall fulfil the following requ
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