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Content for  TS 38.331  Word version:  18.0.0

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7  Variables and constantsp. 1446

7.1  Timersp. 1446

7.1.1  Timers (Informative)p. 1446

Timer Start Stop At expiry
T300Upon transmission of RRCSetupRequest.Upon reception of RRCSetup or RRCReject message, cell re-selection, relay reselection, and upon abortion of connection establishment by upper layers.Perform the actions as specified in clause 5.3.3.7.
T301Upon transmission of RRCReestabilshmentRequestUpon reception of RRCReestablishment or RRCSetup message as well as when the selected cell becomes unsuitable or the (re)selected L2 U2N Relay UE becomes unsuitable, upon reception of NotificationMessageSidelink indicating relayUE-HO or relayUE-CellReselection.Go to RRC_IDLE
T302Upon reception of RRCReject while performing RRC connection establishment or resume, upon reception of RRCRelease with waitTime.Upon entering RRC_CONNECTED or RRC_IDLE, upon cell re-selection, upon cell change due to relay (re)selection, and upon reception of RRCReject message.Inform upper layers about barring alleviation as specified in clause 5.3.14.4
T304 Upon reception of RRCReconfiguration message including reconfigurationWithSync for the MCG which does not include sl-PathSwitchConfig, or upon reception of RRCReconfiguration message including reconfigurationWithSync for the SCG not indicated as deactivated in the NR or E-UTRA message containing the RRCReconfiguration message or upon conditional reconfiguration execution i.e. when applying a stored RRCReconfiguration message including reconfigurationWithSync.
Also, for the MCG and SCG upon an indication from lower layer that an LTM cell switch procedure is triggered and, for the MCG, upon performing an LTM cell switch procedure following cell selection performed while timer T311 is running
Upon successful completion of random access on the corresponding SpCell.
In case of a reconfiguration with sync without performing random access procedure, upon receiving a PDCCH transmission addressed to C-RNTI after first UL transmission, for the same HARQ process.
In case of an LTM cell switch without performing a random access procedure, upon receiving a PDCCH transmission addressed to C-RNTI after first UL transmission, for the same HARQ process.
Upon receiving an indication from lower layers of successful completion of Rach-less handover.
For T304 of MCG, in case of the handover from NR or intra-NR handover, or path switch from a L2 U2N Relay UE to a NR cell, or a reconfiguration with sync without performing random access procedure, or an LTM cell switch procedure, initiate the RRC re-establishment procedure; In case of handover to NR, perform the actions defined in the specifications applicable for the source RAT. If any DAPS bearer is configured and if there is no RLF in source PCell, initiate the failure information procedure.
For T304 of SCG, inform network about the reconfiguration with sync failure by initiating the SCG failure information procedure as specified in clause 5.7.3.
T310Upon detecting physical layer problems for the SpCell i.e. upon receiving N310 consecutive out-of-sync indications from lower layers.Upon receiving N311 consecutive in-sync indications from lower layers for the SpCell, upon receiving RRCReconfiguration with reconfigurationWithSync for that cell group, upon reception of MobilityFromNRCommand, upon the reconfiguration of rlf-TimersAndConstant, upon initiating the connection re-establishment procedure, upon conditional reconfiguration execution i.e. when applying a stored RRCReconfiguration message including reconfigurationWithSync for that cell group, and upon initiating the MCG failure information procedure.
Upon SCG release, if the T310 is kept in SCG.
If the T310 is kept in MCG: If AS security is not activated: go to RRC_IDLE else: initiate the MCG failure information procedure as specified in clause 5.7.3b or the connection re-establishment procedure as specified in clause 5.3.7 or the procedure as specified in clause 5.3.10.3 if any DAPS bearer is configured.
If the T310 is kept in SCG, Inform E-UTRAN/NR about the SCG radio link failure by initiating the SCG failure information procedure as specified in clause 5.7.3.
T311Upon initiating the RRC connection re-establishment procedureUpon selection of a suitable NR cell, or upon selection of a suitable L2 U2N Relay UE, or a cell using another RAT.Enter RRC_IDLE
T312If T312 is configured in MCG: Upon triggering a measurement report for a measurement identity for which T312 has been configured and useT312 has been set to true, while T310 in PCell is running. If T312 is configured in SCG and useT312 has been set to true: Upon triggering a measurement report for a measurement identity for which T312 has been configured, while T310 in PSCell is running.Upon receiving N311 consecutive in-sync indications from lower layers for the SpCell, receiving RRCReconfiguration with reconfigurationWithSync for that cell group, upon reception of MobilityFromNRCommand, upon initiating the connection re-establishment procedure, upon the reconfiguration of rlf-TimersAndConstant, upon initiating the MCG failure information procedure, upon conditional reconfiguration execution i.e. when applying a stored RRCReconfiguration message including reconfigurationWithSync for that cell group, and upon the expiry of T310 in corresponding SpCell. Upon SCG release, if the T312 is kept in SCGIf the T312 is kept in MCG initiate the MCG failure information procedure as specified in clause 5.7.3b or the connection re-establishment procedure. If the T312 is kept in SCG, Inform E-UTRAN/NR about the SCG radio link failure by initiating the SCG failure information procedure.as specified in clause 5.7.3.
T316Upon transmission of the MCGFailureInformation messageUpon receiving RRCRelease, RRCReconfiguration with reconfigurationwithSync for the PCell, MobilityFromNRCommand, or upon initiating the re-establishment procedurePerform the actions as specified in clause 5.7.3b.5.
T319Upon transmission of RRCResumeRequest or RRCResumeRequest1 when the resume procedure is not initiated for SDT.Upon reception of RRCResume, RRCSetup, RRCRelease, RRCRelease with suspendConfig or RRCReject message, upon cell re-selection or upon relay (re)selection.Perform the actions as specified in clause 5.3.13.5.
T319aUpon transmission of RRCResumeRequest or RRCResumeRequest1 when the resume procedure is initiated for SDT.Upon reception of RRCResume, RRCSetup, RRCRelease, RRCReject message or upon failure to resume RRC connection for SDT as specified in clause 5.3.13.5 or upon cell reselection.Perform the actions as specified in clause 5.3.13.5.
T320Upon reception of t320 or upon cell (re)selection to NR from another RAT with validity time configured for dedicated priorities (in which case the remaining validity time is applied).Upon entering RRC_CONNECTED, upon reception of RRCRelease, when PLMN selection or SNPN selection is performed on request by NAS, when the UE enters RRC_IDLE from RRC_INACTIVE, or upon cell (re)selection to another RAT (in which case the timer is carried on to the other RAT).Discard the cell reselection priority information provided by dedicated signalling.
T321Upon receiving measConfig including a reportConfig with the reportType set to reportCGIUpon acquiring the information needed to set all fields of cgi-info, upon receiving measConfig that includes removal of the reportConfig with the reportType set to reportCGI and upon detecting that a cell is not broadcasting SIB1.Initiate the measurement reporting procedure, stop performing the related measurements.
T322Upon receiving measConfig including reportConfigNR with the reportType set to reportSFTD and drx-SFTD-NeighMeas is set to true.Upon acquiring the SFTD measurement results, upon receiving measConfig that includes removal of the reportConfig with the reportType set to reportSFTD.Initiate the measurement reporting procedure, stop performing the related measurements.
T325Upon reception of RRCRelease message with deprioritisationTimer.Stop deprioritisation of all frequencies or NR signalled by RRCRelease.
T330Upon receiving LoggedMeasurementConfiguration messageUpon log volume exceeding the suitable UE memory, upon initiating the release of LoggedMeasurementConfiguration procedurePerform the actions specified in clause 5.5a.1.4
T331Upon receiving RRCRelease message with measIdleDurationUpon receiving RRCSetup, RRCResume, RRCRelease with idle/inactive measurement configuration, upon cell selection/reselection to a cell that does not belong to the validityArea (if configured), or upon cell re-selection to another RAT.Perform the actions as specified in clause 5.7.8.3.
T342Upon transmitting UEAssistanceInformation message with DelayBudgetReport.Upon releasing delayBudgetReportingConfig during the connection re-establishment/resume procedures, and upon receiving delayBudgetReportingConfig set to release.No action.
T345Upon transmitting UEAssistanceInformation message with overheatingAssistanceUpon releasing overheatingAssistanceConfig during the connection re-establishment procedure, upon initiating the connection resumption procedure, and upon receiving overheatingAssistanceConfig set to release.No action.
T346a (The UE maintains one instance of this timer per cell group)Upon transmitting UEAssistanceInformation message with drx-Preference.Upon releasing drx-PreferenceConfig during the connection re-establishment/resume procedures, upon receiving drx-PreferenceConfig set to release, or upon performing MR-DC release.No action.
T346b (The UE maintains one instance of this timer per cell group)Upon transmitting UEAssistanceInformation message with maxBW-Preference.Upon releasing maxBW-PreferenceConfig during the connection re-establishment/resume procedures, upon receiving maxBW-PreferenceConfig set to release, or upon performing MR-DC release.No action.
T346c (The UE maintains one instance of this timer per cell group)Upon transmitting UEAssistanceInformation message with maxCC-Preference.Upon releasing maxCC-PreferenceConfig during the connection re-establishment/resume procedures, upon receiving maxCC-PreferenceConfig set to release, or upon performing MR-DC release.No action.
T346d (The UE maintains one instance of this timer per cell group)Upon transmitting UEAssistanceInformation message with maxMIMO-LayerPreference.Upon releasing maxMIMO-LayerPreferenceConfig during the connection re-establishment/resume procedures, upon receiving maxMIMO-LayerPreferenceConfig set to release, or upon performing MR-DC release.No action.
T346e (The UE maintains one instance of this timer per cell group)Upon transmitting UEAssistanceInformation message with minSchedulingOffsetPreference.Upon releasing minSchedulingOffsetPreferenceConfig during the connection re-establishment/resume procedures, upon receiving minSchedulingOffsetPreferenceConfig set to release, or upon performing MR-DC release.No action.
T346fUpon transmitting UEAssistanceInformation message with releasePreference.Upon releasing releasePreferenceConfig during the connection re-establishment/resume procedures, or upon receiving releasePreferenceConfig set to release.No action.
T346gUpon transmitting UEAssistanceInformation message with musim-PreferredRRC-State.Upon receiving RRCRelease, or upon receiving musim-LeaveAssistanceConfig set to release.Perform the actions as specified in clause 5.3.8.6.
T346hUpon transmitting UEAssistanceInformation message with musim-GapPreferenceList or musim-GapPriorityPreferenceList Information.Upon releasing musim-GapAssistanceConfig during the connection re-establishment/resume procedures, or upon receiving musim-GapAssistanceConfig set to release.No action.
T346iUpon transmitting UEAssistanceInformation message with scg-DeactivationPreferenceUpon releasing scg-DeactivationPreferenceConfig during RRC connection re-establishment/resume or upon receiving scg-DeactivationPreferenceConfig set to release.No action.
T346j (The UE maintains one instance of this timer per cell group)Upon transmitting UEAssistanceInformation message with rlm-RelaxationReportingConfig.Upon releasing rlm-RelaxationReportingConfig during the connection re-establishment/resume procedures, upon receiving rlm-RelaxationReportingConfig set to release, or upon performing MR-DC release.No action.
T346k (The UE maintains one instance of this timer per cell group)Upon transmitting UEAssistanceInformation message with bfd-RelaxationReportingConfig.Upon releasing bfd-RelaxationReportingConfig during the connection re-establishment/resume procedures, upon receiving bfd-RelaxationReportingConfig set to release, or upon performing MR-DC release.No action.
T346l (The UE maintains one instance of this timer per QoS flow)Upon transmitting UEAssistanceInformation message with ul-TrafficInfo for the concerned QoS flow.Upon releasing ul-TrafficInfoReportingConfig during the connection re-establishment/resume procedures, or upon receiving ul-TrafficInfoReportingConfig set to release.No action.
T346mUpon transmitting UEAssistanceInformation message with multiRx-PreferenceFR2.Upon releasing multiRx-PreferenceReportingConfigFR2 during the connection re-establishment/resume procedures, upon receiving multiRx-PreferenceReportingConfigFR2 set to release.No action.
T346nUpon transmission of MUSIM temporary restriction of musim-CapRestriction for constraint combination of bands and/or band(s) or combination bands to avoid Upon releasing musim-CapabilityRestrictionConfig during the connection re-establishment/resume procedures, or upon receiving musim-CapabilityRestrictionConfig set to release.No action.
T348Upon transmission of MUSIM temporary restriction of musim-CapRestriction for serving cell(s) with capabilities restricted, release of SCell or release of SCG. Upon reception of RRCReconfiguration message that does not exceed UE temporary capability restriction transmitted via musim-CapRestriction.UE may apply the temporary UE capability restriction in accordance with the one indicated in the last transmission of the UEAssistanceInformation message including musim-CapRestriction.
T350Upon transmitting DedicatedSIBRequest message with requestedSIB-List and/or requestedPosSIB-List.Upon acquiring the requested SIB(s) or posSIB(s), upon releasing onDemandSIB-Request during the connection re-establishment procedures, upon receiving onDemandSIB-Request set to release, upon reception of RRCRelease or upon successful change of PCell while in RRC_CONNECTED.No action
T380Upon reception of t380 in RRCRelease.Upon reception of RRCResume, RRCSetup or RRCRelease.Perform the actions as specified in clause 5.3.13.
T390When access attempt is barred at access barring check for an Access Category. The UE maintains one instance of this timer per Access Category.Upon cell (re)selection, upon relay (re)selection, upon entering RRC_CONNECTED, upon reception of RRCReconfiguration including reconfigurationWithSync, upon change of PCell while in RRC_CONNECTED, upon reception of MobilityFromNRCommand, or upon reception of RRCRelease.Perform the actions as specified in clause 5.3.14.4.
T400Upon transmission of RRCReconfigurationSidelinkUpon reception of RRCReconfigurationFailureSidelink or RRCReconfigurationCompleteSidelinkPerform the Sidelink radio link failure related actions as specified in clause 5.8.9.3.
T420Upon reception of the RRCReconfiguration message including sl-PathSwitchConfigUpon successfully sending RRCReconfigurationComplete message (i.e., PC5 RLC acknowledgement is received from target L2 U2N Relay UE)Perform the RRC re-establishment procedure as specified in clause 5.3.7.
T421Upon reception of the RRCReconfiguration message including sl-IndirectPathAddChangeUpon successfully sending RRCReconfigurationComplete message (i.e., PC5 RLC acknowledgement is received from target L2 U2N Relay UE) if split SRB1 with duplication is configured;Perform the Failure Information Reporting as specified in clause 5.7.3c.
T430Start or restart from the subframe indicated by epochTime upon reception of SIB19, or upon reception of RRCReconfiguration message for the target cell including reconfigurationWithSync, or upon conditional reconfiguration execution i.e. when applying a stored RRCReconfiguration message for the target cell including reconfigurationWithSync.Stop T430, if it is running, for the source cell upon reception of RRCReconfiguration message including reconfigurationWithSync, or upon conditional reconfiguration execution i.e. when applying a stored RRCReconfiguration message including reconfigurationWithSync.Perform the actions as specified in clause 5.2.2.6.
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7.1.2  Timer handlingp. 1456

When the UE applies zero value for a timer, the timer shall be started and immediately expire unless explicitly stated otherwise.

7.2  Countersp. 1457

Counter Reset Incremented When reaching max value
N310 Upon reception of "in-sync" indication from lower layers;
upon receiving RRCReconfiguration with reconfigurationWithSync for that cell group;
upon initiating the connection re-establishment procedure.
Upon reception of "out-of-sync" from lower layer while the timer T310 is stopped. Start timer T310
N311 Upon reception of "out-of-sync" indication from lower layers;
upon receiving RRCReconfiguration with reconfigurationWithSync for that cell group;
upon initiating the connection re-establishment procedure.
Upon reception of the "in-sync" from lower layer while the timer T310 is running. Stop the timer T310.
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7.3  Constantsp. 1457

Constant Usage
N310 Maximum number of consecutive "out-of-sync" indications for the SpCell received from lower layers
N311 Maximum number of consecutive "in-sync" indications for the SpCell received from lower layers
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7.4  UE variablesp. 1457

 –  NR-UE-Variablesp. 1457

This ASN.1 segment is the start of the NR UE variable definitions.
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 –  VarAppLayerIdleConfigp. 1459

The UE variable VarAppLayerIdleConfig includes the parameters of the application layer measurements stored in the UE while in RRC_IDLE.
VarAppLayerIdleConfig UE variable
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 –  VarAppLayerPLMN-LisConfigp. 1460

The UE variable VarAppLayerPLMN-ListConfig includes the PLMNs to which application layer measurement reports and application layer measurement configurations are allowed to be sent.
VarAppLayerPLMN-ListConfig UE variable
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 –  VarConditionalReconfigp. 1460

The UE variable VarConditionalReconfig includes the accumulated configuration of the conditional handover, conditional PSCell addition or conditional PSCell change configurations including the pointers to conditional handover, conditional PSCell addition, conditional PSCell change, or subsequent CPAC execution condition (associated measId(s)), the stored target candidate SpCell RRCReconfiguration, the stored reference configuration, and the stored SK-Counter configuration.
VarConditionalReconfig UE variable
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 –  VarConnEstFailReportp. 1461

The UE variable VarConnEstFailReport includes the connection establishment failure and/or connection resume failure information.
VarConnEstFailReport UE variable
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 –  VarConnEstFailReportListp. 1461

The UE variable VarConnEstFailReportList includes a list of the connection establishment failure and/or connection resume failure information.
VarConnEstFailReportList UE variable
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 –  VarEventIDp. 1462

The UE variable VarEventID includes information about the current value of eventID-TSS received in SIB9 or in DLInformationTransfer.
VarEventID UE variable

 –  VarGnbIDp. 1462

The UE variable VarGnbID includes information about the current value of GnbID received as the value of gNB-ID-Length leftmost bits of the 36-bit long cellIdentity in the first PLMN-IdentityInfo IE of PLMN-IdentityInfoList in SIB1.
VarGnbID UE variable
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 –  VarLogMeasConfigp. 1462

The UE variable VarLogMeasConfig includes the configuration of the logging of measurements to be performed by the UE while in RRC_IDLE, RRC_INACTIVE, covering intra-frequency, inter-frequency and inter-RAT mobility related measurements. The UE performs logging of measurements only while in RRC_IDLE and RRC_INACTIVE.
VarLogMeasConfig UE variable
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 –  VarLogMeasReportp. 1463

The UE variable VarLogMeasReport includes the logged measurements information.
VarLogMeasReport UE variable
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 –  VarLTM-Configp. 1463

The IE VarLTM-Config is used to store the reference configuration and the LTM candidate configurations.
VarLTM-Config UE variable
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 –  VarLTM-ServingCellNoResetIDp. 1464

The IE VarLTM-ServingCellNoResetID is used to store the serving cell ID based on which the UE determines whether a L2 reset is needed or not upon an LTM cell switch procedure.
VarLTM-ServingCellNoResetID UE variable
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 –  VarLTM-ServingCellUE-MeasuredTA-IDp. 1464

The IE VarLTM-ServingCellUE-MeasuredTA-ID is used to store the serving cell ID based on which the UE determines whether UE-based TA measurements are needed or not upon an LTM cell switch procedure.
VarLTM-ServingCellUE-MeasuredTA-ID UE variable
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 –  VarMeasConfigp. 1465

The UE variable VarMeasConfig includes the accumulated configuration of the measurements to be performed by the UE, covering intra-frequency, inter-frequency and inter-RAT mobility related measurements.
VarMeasConfig UE variable
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 –  VarMeasConfigSLp. 1465

The UE variable VarMeasConfigSL includes the accumulated configuration of the NR sidelink measurements to be performed by the UE of unicast destination.
VarMeasConfigSL UE variable
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 –  VarMeasIdleConfigp. 1466

The UE variable VarMeasIdleConfig includes the configuration of the measurements to be performed by the UE while in RRC_IDLE or RRC_INACTIVE for NR inter-frequency and inter-RAT (i.e. EUTRA) measurements.
VarMeasIdleConfig UE variable
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 –  VarMeasIdleReportp. 1466

The UE variable VarMeasIdleReport includes the logged measurements information.
VarMeasIdleReport UE variable
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 –  VarMeasReportListp. 1466

The UE variable VarMeasReportList includes information about the measurements for which the triggering conditions have been met.
VarMeasReportList UE variable
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 –  VarMeasReportListSLp. 1467

The UE variable VarMeasReportListSL includes information about the NR sidelink measurements for which the triggering conditions have been met.
VarMeasReportListSL UE variable
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 –  VarMobilityHistoryReportp. 1468

The UE variable VarMobilityHistoryReport includes the mobility history information.
VarMobilityHistoryReport UE variable
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 –  VarPendingRNA-Updatep. 1468

The UE variable VarPendingRNA-Update indicates whether there is a pending RNA update procedure or not. The setting of this BOOLEAN variable to true means that there is a pending RNA Update procedure.
VarPendingRNA-Update UE variable
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 –  VarRA-Reportp. 1469

The UE variable VarRA-Report includes the random-access related information.
VarRA-Report UE variable
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 –  VarResumeMAC-Inputp. 1469

The UE variable VarResumeMAC-Input specifies the input used to generate the resumeMAC-I during RRC Connection Resume procedure.
VarResumeMAC-Input variable
VarResumeMAC-Input field descriptions
targetCellIdentity
An input variable used to calculate the resumeMAC-I. Set to the cellIdentity of the first PLMN-Identity included in the PLMN-IdentityInfoList broadcasted in SIB1 of the target cell i.e. the cell the UE is trying to resume.
source-c-RNTI
Set to C-RNTI that the UE had in the PCell it was connected to prior to suspension of the RRC connection.
sourcePhysCellId
Set to the physical cell identity of the PCell the UE was connected to prior to suspension of the RRC connection.
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 –  VarRLF-Reportp. 1470

The UE variable VarRLF-Report includes the radio link failure information or handover failure information.
VarRLF-Report UE variable
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 –  VarServingSecurityCellSetIDp. 1470

The UE variable VarServingSecurityCellSetID includes the security cell set ID of serving PSCell.
VarServingSecurityCellSetID UE variable
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 –  VarShortMAC-Inputp. 1471

The UE variable VarShortMAC-Input specifies the input used to generate the shortMAC-I during RRC Connection Reestablishment procedure.
VarShortMAC-Input variable
VarShortMAC-Input field descriptions
targetCellIdentity
An input variable used to calculate the shortMAC-I. Set to the cellIdentity of the first PLMN-Identity in the PLMN-IdentityInfoList broadcasted in SIB1 of the target cell i.e. the cell the UE is trying to reestablish the connection.
source-c-RNTI
Set to C-RNTI that the UE had in the PCell it was connected to prior to the reestablishment.
sourcePhysCellId
Set to the physical cell identity of the PCell the UE was connected to prior to the reestablishment.
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 –  VarSuccessHO-Reportp. 1471

The UE variable VarSuccessHO-Report includes the successful handover information.
VarSccessHO-Report variable
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 –  VarSuccessPSCell-Reportp. 1472

The UE variable VarSuccessPSCell-Report includes the successful PSCell change or addition information.
VarSuccessPSCell-Report variable
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 –  End of NR-UE-Variablesp. 1472

8  Protocol data unit abstract syntaxp. 1473

8.1  Generalp. 1473

The RRC PDU contents in clause 6 and clause 10 are described using abstract syntax notation one (ASN.1) as specified in ITU-T Rec. X.680 [6] and X.681 [7]. Transfer syntax for RRC PDUs is derived from their ASN.1 definitions by use of Packed Encoding Rules, unaligned as specified in ITU-T Rec. X.691 [8].
The following encoding rules apply in addition to what has been specified in X.691:
  • When a bit string value is placed in a bit-field as specified in 15.6 to 15.11 in X.691, the leading bit of the bit string value shall be placed in the leading bit of the bit-field, and the trailing bit of the bit string value shall be placed in the trailing bit of the bit-field;
  • When decoding types constrained with the ASN.1 Contents Constraint ("CONTAINING"), automatic decoding of the contained type should not be performed because errors in the decoding of the contained type should not cause the decoding of the entire RRC message PDU to fail. It is recommended that the decoder first decodes the outer PDU type that contains the OCTET STRING or BIT STRING with the Contents Constraint, and then decodes the contained type that is nested within the OCTET STRING or BIT STRING as a separate step;
  • When decoding a) RRC message PDUs, b) BIT STRING constrained with a Contents Constraint, or c) OCTET STRING constrained with a Contents Constraint, PER decoders are required to never report an error if there are extraneous zero or non-zero bits at the end of the encoded RRC message PDU, BIT STRING or OCTET STRING.
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8.2  Structure of encoded RRC messagesp. 1473

An RRC PDU, which is the bit string that is exchanged between peer entities/across the radio interface contains the basic production as defined in X.691.
RRC PDUs shall be mapped to and from PDCP SDUs (in case of DCCH) or RLC SDUs (in case of PCCH, BCCH or CCCH) upon transmission and reception as follows:
  • when delivering an RRC PDU as an PDCP SDU to the PDCP layer for transmission, the first bit of the RRC PDU shall be represented as the first bit in the PDCP SDU and onwards; and
  • when delivering an RRC PDU as an RLC SDU to the RLC layer for transmission, the first bit of the RRC PDU shall be represented as the first bit in the RLC SDU and onwards; and
  • upon reception of an PDCP SDU from the PDCP layer, the first bit of the PDCP SDU shall represent the first bit of the RRC PDU and onwards; and
  • upon reception of an RLC SDU from the RLC layer, the first bit of the RLC SDU shall represent the first bit of the RRC PDU and onwards.
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8.3  Basic productionp. 1473

The 'basic production' is obtained by applying UNALIGNED PER to the abstract syntax value (the ASN.1 description) as specified in X.691. It always contains a multiple of 8 bits.

8.4  Extensionp. 1473

The following rules apply with respect to the use of protocol extensions:
  • A transmitter compliant with this version of the specification shall, unless explicitly indicated otherwise on a PDU type basis, set the extension part empty. Transmitters compliant with a later version may send non-empty extensions;
  • A transmitter compliant with this version of the specification shall set spare bits to zero.

8.5  Paddingp. 1474

If the encoded RRC message does not fill a transport block, the RRC layer shall add padding bits. This applies to PCCH and BCCH.
Padding bits shall be set to 0 and the number of padding bits is a multiple of 8.
Reproduction of 3GPP TS 38.331, Fig. 8.5-1: RRC level padding
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