ETSI TS 138 331 V15.8.0 (2020-01)

ETSI TS 138 331 V15.8.0 (2020-01)






TECHNICAL SPECIFICATION
5G;
NR;
Radio Resource Control (RRC);
Protocol specification
(3GPP TS 38.331 version 15.8.0 Release 15)

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3GPP TS 38.331 version 15.8.0 Release 15 1 ETSI TS 138 331 V15.8.0 (2020-01)



Reference
RTS/TSGR-0238331vf80
Keywords
5G
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3GPP TS 38.331 version 15.8.0 Release 15 2 ETSI TS 138 331 V15.8.0 (2020-01)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is 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 Web
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Pursuant to the ETSI IPR Policy, no investigation, 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
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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
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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

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3GPP TS 38.331 version 15.8.0 Release 15 3 ETSI TS 138 331 V15.8.0 (2020-01)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 15
1 Scope . 16
2 References . 16
3 Definitions, symbols and abbreviations . 18
3.1 Definitions . 18
3.2 Abbreviations . 18
4 General . 20
4.1 Introduction . 20
4.2 Architecture . 20
4.2.1 UE states and state transitions including inter RAT . 20
4.2.2 Signalling radio bearers . 22
4.3 Services . 23
4.3.1 Services provided to upper layers . 23
4.3.2 Services expected from lower layers . 23
4.4 Functions . 23
5 Procedures . 24
5.1 General . 24
5.1.1 Introduction. 24
5.1.2 General requirements . 24
5.1.3 Requirements for UE in MR-DC . 25
5.2 System information . 25
5.2.1 Introduction. 25
5.2.2 System information acquisition . 26
5.2.2.1 General UE requirements . 26
5.2.2.2 SIB validity and need to (re)-acquire SIB . 27
5.2.2.2.1 SIB validity . 27
5.2.2.2.2 SI change indication and PWS notification . 27
5.2.2.3 Acquisition of System Information . 28
5.2.2.3.1 Acquisition of MIB and SIB1 . 28
5.2.2.3.2 Acquisition of an SI message . 29
5.2.2.3.3 Request for on demand system information . 29
5.2.2.3.4 Actions related to transmission of RRCSystemInfoRequest message . 30
5.2.2.4 Actions upon receipt of System Information . 30
5.2.2.4.1 Actions upon reception of the MIB . 30
5.2.2.4.2 Actions upon reception of the SIB1 . 31
5.2.2.4.3 Actions upon reception of SIB2 . 33
5.2.2.4.4 Actions upon reception of SIB3 . 34
5.2.2.4.5 Actions upon reception of SIB4 . 34
5.2.2.4.6 Actions upon reception of SIB5 . 35
5.2.2.4.7 Actions upon reception of SIB6 . 35
5.2.2.4.8 Actions upon reception of SIB7 . 35
5.2.2.4.9 Actions upon reception of SIB8 . 36
5.2.2.4.10 Actions upon reception of SIB9 . 37
5.2.2.5 Essential system information missing . 37
5.3 Connection control . 37
5.3.1 Introduction. 37
5.3.1.1 RRC connection control . 37
5.3.1.2 AS Security . 38
5.3.2 Paging . 39
5.3.2.1 General . 39
ETSI

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3GPP TS 38.331 version 15.8.0 Release 15 4 ETSI TS 138 331 V15.8.0 (2020-01)
5.3.2.2 Initiation . 39
5.3.2.3 Reception of the Paging message by the UE . 39
5.3.3 RRC connection establishment . 40
5.3.3.1 General . 40
5.3.3.2 Initiation . 41
5.3.3.3 Actions related to transmission of RRCSetupRequest mes sa ge . 41
5.3.3.4 Reception of the RRCSetup by the UE . 41
5.3.3.5 Reception of the RRCReject by the UE . 43
5.3.3.6 Cell re-selection or cell selection while T390, T300 or T302 is running (UE in RRC_IDLE) . 43
5.3.3.7 T300 expiry . 43
5.3.3.8 Abortion of RRC connection establishment . 44
5.3.4 Initial AS security activation . 44
5.3.4.1 General . 44
5.3.4.2 Initiation . 44
5.3.4.3 Reception of the SecurityModeCommand by the UE . 44
5.3.5 RRC reconfiguration . 45
5.3.5.1 General . 45
5.3.5.2 Initiation . 46
5.3.5.3 Reception of an RRCReconfiguration by the UE . 46
5.3.5.4 Secondary cell group release . 49
5.3.5.5 Cell Group configuration . 49
5.3.5.5.1 General . 49
5.3.5.5.2 Reconfiguration with sync . 50
5.3.5.5.3 RLC bearer release . 51
5.3.5.5.4 RLC bearer addition/modification . 51
5.3.5.5.5 MAC entity configuration . 51
5.3.5.5.6 RLF Timers & Constants configuration . 52
5.3.5.5.7 SpCell Configuration . 52
5.3.5.5.8 SCell Release . 53
5.3.5.5.9 SCell Addition/Modification . 53
5.3.5.6 Radio Bearer configuration . 53
5.3.5.6.1 General . 53
5.3.5.6.2 SRB release . 54
5.3.5.6.3 SRB addition/modification . 54
5.3.5.6.4 DRB release . 55
5.3.5.6.5 DRB addition/modification . 56
5.3.5.7 AS Security key update . 58
5.3.5.8 Reconfiguration failure . 59
5.3.5.8.1 Void . 59
5.3.5.8.2 Inability to comply with RRCReconfiguration . 59
5.3.5.8.3 T304 expiry (Reconfiguration with sync Failure) . 60
5.3.5.9 Other configuration . 60
5.3.5.10 MR-DC release . 61
5.3.5.11 Full configuration . 61
5.3.6 Counter check . 62
5.3.6.1 General . 62
5.3.6.2 Initiation . 62
5.3.6.3 Reception of the CounterCheck message by the UE . 62
5.3.7 RRC connection re-establishment . 63
5.3.7.1 General . 63
5.3.7.2 Initiation . 64
5.3.7.3 Actions following cell selection while T311 is running . 64
5.3.7.4 Actions related to transmission of RRCReestablishmentRequest message . 65
5.3.7.5 Reception of the RRCReestablishment by the UE . 66
5.3.7.6 T311 expiry . 66
5.3.7.7 T301 expiry or selected cell no longer suitable . 66
5.3.7.8 Reception of the RRCSetup by the UE . 67
5.3.8 RRC connection release . 67
5.3.8.1 General . 67
5.3.8.2 Initiation . 67
5.3.8.3 Reception of the RRCRelease by the UE . 67
5.3.8.4 T320 expiry . 69
ETSI

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3GPP TS 38.331 version 15.8.0 Release 15 5 ETSI TS 138 331 V15.8.0 (2020-01)
5.3.8.5 UE actions upon the expiry of DataInactivityTimer . 69
5.3.9 RRC connection release requested by upper layers . 69
5.3.9.1 General . 69
5.3.9.2 Initiation . 69
5.3.10 Radio link failure related actions . 69
5.3.10.1 Detection of physical layer problems in RRC_CONNECTED . 69
5.3.10.2 Recovery of physical layer problems . 70
5.3.10.3 Detection of radio link failure . 70
5.3.11 UE actions upon going to RRC_IDLE . 71
5.3.12 UE actions upon PUCCH/SRS release request . 71
5.3.13 RRC connection resume . 72
5.3.13.1 General . 72
5.3.13.2 Initiation . 73
5.3.13.3 Actions related to transmission of RRCResumeRequest or RRCResumeRequest1 message . 74
5.3.13.4 Reception of the RRCResume by the UE . 75
5.3.13.5 T319 expiry or Integrity check failure from lower layers while T319 is running . 76
5.3.13.6 Cell re-selection or cell selection while T390, T319 or T302 is running (UE in
RRC_INACTIVE) . 77
5.3.13.7 Reception of the RRCSetup by the UE . 77
5.3.13.8 RNA update. 77
5.3.13.9 Reception of the RRCRelease by the UE . 77
5.3.13.10 Reception of the RRCReject by the UE . 77
5.3.13.11 Inability to comply with RRCResume . 77
5.3.13.12 Inter RAT cell reselection . 78
5.3.14 Unified Access Control . 78
5.3.14.1 General . 78
5.3.14.2 Initiation . 78
5.3.14.3 Void. 80
5.3.14.4 T302, T390 expiry or stop (Barring alleviation) . 80
5.3.14.5 Access barring check. 80
5.3.15 RRC connection reject . 81
5.3.15.1 Initiation . 81
5.3.15.2 Reception of the RRCReject by the UE . 81
5.4 Inter-RAT mobility. 81
5.4.1 Introduction. 81
5.4.2 Handover to NR . 82
5.4.2.1 General . 82
5.4.2.2 Initiation . 82
5.4.2.3 Reception of the RRCReconfiguration by the UE . 82
5.4.3 Mobility from NR . 83
5.4.3.1 General . 83
5.4.3.2 Initiation . 83
5.4.3.3 Reception of the MobilityFromNRCommand by the UE. 83
5.4.3.4 Successful completion of the mobility from NR . 83
5.4.3.5 Mobility from NR failure . 84
5.5 Measurements .
...