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Content for  TS 38.304  Word version:  18.1.0

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5.2.4.7  Cell reselection parameters in system information broadcastsp. 29

5.2.4.7.0  General reselection parametersp. 29
Cell reselection parameters are broadcast in system information and are read from the serving cell as follows:
absThreshSS-BlocksConsolidation
This specifies the minimum threshold for beams which can be used for selection of the highest ranked cells, if rangeToBestCell is configured, and for beams used for derivation of cell measurement quantity. The parameter in SIB2 applies to the current serving frequency and the parameter in SIB4 applies to the corresponding inter-frequency.
cellReselectionPriority
This specifies the absolute priority for NR frequency or E-UTRAN frequency.
cellReselectionSubPriority
This specifies the fractional priority value added to cellReselectionPriority for NR frequency or E-UTRAN frequency.
combineRelaxedMeasCondition
This indicates when the UE needs to fulfil both low mobility criterion and not-at-cell-edge criterion to determine whether to relax measurement requirements.
combineRelaxedMeasCondition2
This indicates when an (e)RedCap UE needs to fulfil both stationary criterion and not-at-cell-edge criterion to determine whether to relax measurement requirements.
coverageAreaInfoList
This indicates a list of TN coverage areas to assist skipping TN measurements for NTN UEs in RRC_IDLE and RRC_INACTIVE states.
distanceThresh
This indicates the distance threshold from the serving cell reference location to be used in location-based measurement initiation.
movingReferenceLocation
This indicates the reference location of the serving cell at a time reference, to be used in location-based measurement initiation for NTN Earth-moving system.
nrofSS-BlocksToAverage
This specifies the number of beams which can be used for selection of the highest ranked cell, if rangeToBestCell is configured, and the number of beams used for derivation of cell measurement quantity. The parameter in SIB2 applies to the current serving frequency and the parameter in SIB4 applies to the corresponding inter-frequency.
Qoffsets,n
This specifies the offset between the two cells.
Qoffsetfrequency
Frequency specific offset for equal priority NR frequencies.
Qhyst
This specifies the hysteresis value for ranking criteria.
Qoffsettemp
This specifies the additional offset to be used for cell selection and re-selection. It is temporarily used in case the RRC Connection Establishment fails on the cell as specified in TS 38.331.
Qqualmin
This specifies the minimum required quality level in the cell in dB.
Qrxlevmin
This specifies the minimum required Rx level in the cell in dBm.
Qrxlevminoffsetcell
This specifies the cell specific Rx level offset in dB to Qrxlevmin.
Qqualminoffsetcell
This specifies the cell specific quality level offset in dB to Qqualmin.
rangeToBestCell
This specifies the R value range which the cells whose R value is within the range can be a candidate for the highest ranked cell. It is configured in SIB2 and used for intra-frequency and equal priority inter-frequency cell reselection and among the cells on the highest priority frequency(ies) for inter-frequency cell reselection within NR.
referenceLocation
This indicates the reference location of the serving cell to be used in location-based measurement initiation for NTN (quasi-)Earth-fixed system.
SIntraSearchP
This specifies the Srxlev threshold (in dB) for intra-frequency measurements.
SIntraSearchQ
This specifies the Squal threshold (in dB) for intra-frequency measurements.
SnonIntraSearchP
This specifies the Srxlev threshold (in dB) for NR inter-frequency and inter-RAT measurements.
SnonIntraSearchQ
This specifies the Squal threshold (in dB) for NR inter-frequency and inter-RAT measurements.
SSearchDeltaP
This specifies the threshold (in dB) on Srxlev variation for relaxed measurement.
SSearchDeltaP-Stationary
This specifies the threshold (in dB) on Srxlev variation to evaluate stationary criterion for relaxed measurement.
SSearchThresholdP
This specifies the Srxlev threshold (in dB) for relaxed measurement.
SSearchThresholdP2
This specifies the Srxlev threshold (in dB) to evaluate not-at-cell-edge-criterion for relaxed measurement.
SSearchThresholdQ
This specifies the Squal threshold (in dB) for relaxed measurement.
SSearchThresholdQ2
This specifies the Squal threshold (in dB) to evaluate not-at-cell-edge-criterion for relaxed measurement.
TreselectionRAT
This specifies the cell reselection timer value. For each target NR frequency and for each RAT other than NR, a specific value for the cell reselection timer is defined, which is applicable when evaluating reselection within NR or towards other RAT (i.e. TreselectionRAT for NR is TreselectionNR, for E-UTRAN TreselectionEUTRA).
TreselectionNR
This specifies the cell reselection timer value TreselectionRAT for NR. The parameter can be set per NR frequency as specified in TS 38.331.
TreselectionEUTRA
This specifies the cell reselection timer value TreselectionRAT for E-UTRAN.
ThreshX, HighP
This specifies the Srxlev threshold (in dB) used by the UE when reselecting towards a higher priority RAT/ frequency than the current serving frequency. Each frequency of NR and E-UTRAN might have a specific threshold.
ThreshX, HighQ
This specifies the Squal threshold (in dB) used by the UE when reselecting towards a higher priority RAT/ frequency than the current serving frequency. Each frequency of NR and E-UTRAN might have a specific threshold.
ThreshX, LowP
This specifies the Srxlev threshold (in dB) used by the UE when reselecting towards a lower priority RAT/ frequency than the current serving frequency. Each frequency of NR and E-UTRAN might have a specific threshold.
ThreshX, LowQ
This specifies the Squal threshold (in dB) used by the UE when reselecting towards a lower priority RAT/ frequency than the current serving frequency. Each frequency of NR and E-UTRAN might have a specific threshold.
ThreshServing, LowP
This specifies the Srxlev threshold (in dB) used by the UE on the serving cell when reselecting towards a lower priority RAT/ frequency.
ThreshServing, LowQ
This specifies the Squal threshold (in dB) used by the UE on the serving cell when reselecting towards a lower priority RAT/ frequency.
TSearchDeltaP
This specifies the time period over which the Srxlev variation is evaluated for relaxed measurement.
TSearchDeltaP-Stationary
This specifies the time period over which the Srxlev variation is evaluated for stationary criterion for relaxed measurement.
t-Service
This indicates the time when an NTN cell is going to stop serving the area where it is currently covering, to be used in time-based measurement initiation.
tn-AreaIdList
This indicates a list of TN area identities associated with each frequency to assist skipping TN measurements for NTN UEs in RRC_IDLE and RRC_INACTIVE states. Each TN area identity in the list identifies a TN coverage area.
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5.2.4.7.1  Speed dependent reselection parametersp. 32
Speed dependent reselection parameters are broadcast in system information and are read from the serving cell as follows:
TCRmax
This specifies the duration for evaluating allowed amount of cell reselection(s).
NCR_M
This specifies the maximum number of cell reselections to enter Medium-mobility state.
NCR_H
This specifies the maximum number of cell reselections to enter High-mobility state.
TCRmaxHyst
This specifies the additional time period before the UE can enter Normal-mobility state.
Speed dependent ScalingFactor for Qhyst
This specifies scaling factor for Qhyst in sf-High for High-mobility state and sf-Medium for Medium-mobility state.
Speed dependent ScalingFactor for TreselectionNR
This specifies scaling factor for TreselectionNR in sf-High for High-mobility state and sf-Medium for Medium-mobility state.
Speed dependent ScalingFactor for TreselectionEUTRA
This specifies scaling factor for TreselectionEUTRA in sf-High for High-mobility state and sf-Medium for Medium-mobility state.
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5.2.4.7.2  Slice-based cell reselection parameters |R17|p. 33
Slice-based cell reselection parameters are broadcast in system information and are read from the serving cell as follows:
nsag-CellReselectionPriority
This specifies the priority for NR frequency when the given NSAG ID is used to set the frequency priority.
nsag-CellReselectionSubPriority
This specifies the fractional priority value added to nsag-CellReselectionPriority when the given NSAG ID is used to set the frequency priority.

5.2.4.8  Inter-RAT Cell reselection in RRC_INACTIVE statep. 33

For UE in the RRC_INACTIVE state, upon cell reselection to another RAT, UE transitions from RRC_INACTIVE to RRC_IDLE and performs actions as specified in TS 38.331.

5.2.4.9  Relaxed measurement |R16|p. 33

5.2.4.9.0  Relaxed measurement rulesp. 33
When the UE is required to perform measurements of intra-frequency cells or NR inter-frequency cells or inter-RAT frequency cells according to the measurement rules in clause 5.2.4.2:
  • if lowMobilityEvaluation is configured and cellEdgeEvaluation is not configured; and
  • if the UE has performed normal intra-frequency, NR inter-frequency, or inter-RAT frequency measurements for at least TSearchDeltaP after (re-)selecting a new cell; and
  • if the relaxed measurement criterion in clause 5.2.4.9.1 is fulfilled for a period of TSearchDeltaP:
  • if cellEdgeEvaluation is configured and lowMobilityEvaluation is not configured; and
  • if the relaxed measurement criterion in clause 5.2.4.9.2 is fulfilled:
    • the UE may choose to perform relaxed measurements for intra-frequency cells according to relaxation methods in clauses 4.2.2.9 and 4.2C.2.7 in TS 38.133;
    • if the serving cell fulfils Srxlev ≤ SnonIntraSearchP or Squal ≤ SnonIntraSearchQ:
  • if both lowMobilityEvaluation and cellEdgeEvaluation are configured:
    • if the UE has performed normal intra-frequency, NR inter-frequency, or inter-RAT frequency measurements for at least TSearchDeltaP after (re-)selecting a new cell; and
    • if the relaxed measurement criterion in clause 5.2.4.9.1 is fulfilled for a period of TSearchDeltaP; and
    • if the relaxed measurement criterion in clause 5.2.4.9.2 is fulfilled:
    • else:
      • if the UE has performed normal intra-frequency, NR inter-frequency, or inter-RAT frequency measurements for at least TSearchDeltaP after (re-)selecting a new cell, and the relaxed measurement criterion in clause 5.2.4.9.1 is fulfilled for a period of TSearchDeltaP; or,
      • if the relaxed measurement criterion in clause 5.2.4.9.2 is fulfilled:
        • if combineRelaxedMeasCondition is not configured:
          • the UE may choose to perform relaxed measurements for intra-frequency cells, NR inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority according to relaxation methods in clauses 4.2.2.9, 4.2.2.10, 4.2.2.11, 4.2C.2.7 and 4.2C.2.8 in TS 38.133;
          • if the serving cell fulfils Srxlev ≤ SnonIntraSearchP or Squal ≤ SnonIntraSearchQ:
            • the UE may choose to perform relaxed measurement for NR inter-frequency cells of higher priority, or inter-RAT frequency cells of higher priority according to relaxation methods in clauses 4.2.2.10, 4.2.2.11 and 4.2C.2.8 in TS 38.133;
    • if the UE is an (e)RedCap UE; and
    • if stationaryMobilityEvaluation is configured and cellEdgeEvaluationWhileStationary is not configured; and
    • if the UE has performed normal intra-frequency, NR inter-frequency, or inter-RAT frequency measurements for at least TSearchDeltaP-Stationary after (re-)selecting a new cell; and
    • if the relaxed measurement criterion in clause 5.2.4.9.3 is fulfilled for a period of TSearchDeltaP-Stationary:
      • the UE may choose to perform relaxed measurements for intra-frequency cells, NR inter-frequency cells, or inter-RAT frequency cells according to relaxation methods in clauses 4.2B.2.9, 4.2B.2.10, and 4.2B.2.11 in TS 38.133;
    • if the UE is an (e)RedCap UE; and
    • if both stationaryMobilityEvaluation and cellEdgeEvaluationWhileStationary are configured:
      • if the UE has performed normal intra-frequency, NR inter-frequency, or inter-RAT frequency measurements for at least TSearchDeltaP-Stationary after (re-)selecting a new cell; and
      • if the relaxed measurement criterion in clause 5.2.4.9.4 is fulfilled:
        • the UE may choose to perform relaxed measurements for intra-frequency cells, NR inter-frequency cells, or inter-RAT frequency cells according to relaxation methods in clauses 4.2B.2.9, 4.2B.2.10, and 4.2B.2.11 in TS 38.133;
      • else:
        • if combineRelaxedMeasCondition2 is not configured:
          • if the UE has performed normal intra-frequency, NR inter-frequency, or inter-RAT frequency measurements for at least TSearchDeltaP-Stationary after (re-)selecting a new cell; and
          • if the relaxed measurement criterion in clause 5.2.4.9.3 is fulfilled for a period of TSearchDeltaP-Stationary:
            • the UE may choose to perform relaxed measurements for intra-frequency cells, NR inter-frequency cells, or inter-RAT frequency cells according to relaxation methods in clauses 4.2B.2.9, 4.2B.2.10, and 4.2B.2.11 in TS 38.133;
    The above relaxed measurements and no measurement are not applicable for frequencies that are included in VarMeasIdleConfig, if configured and for which the UE supports dual connectivity or carrier aggregation between those frequencies and the frequency of the current serving cell.
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5.2.4.9.1  Relaxed measurement criterion for UE with low mobilityp. 35
The relaxed measurement criterion for UE with low mobility is fulfilled when:
  • (SrxlevRef - Srxlev) < SSearchDeltaP,
Where:
  • Srxlev = current Srxlev value of the serving cell (dB).
  • SrxlevRef = reference Srxlev value of the serving cell (dB), set as follows:
    • After selecting or reselecting a new cell, or
    • If (Srxlev - SrxlevRef) > 0, or
    • If the relaxed measurement criterion has not been met for TSearchDeltaP:
      • The UE shall set the value of SrxlevRef to the current Srxlev value of the serving cell.
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5.2.4.9.2  Relaxed measurement criterion for UE not at cell edgep. 35
The relaxed measurement criterion for UE not at cell edge is fulfilled when:
  • Srxlev > SSearchThresholdP, and,
  • Squal > SSearchThresholdQ, if SSearchThresholdQ is configured,
Where:
  • Srxlev = current Srxlev value of the serving cell (dB).
  • Squal = current Squal value of the serving cell (dB).
5.2.4.9.3  Relaxed measurement criterion for a stationary (e)RedCap UE |R17|p. 35
The relaxed measurement criterion for a stationary (e)RedCap UE is fulfilled when:
  • (SrxlevRefStationary - Srxlev) < SSearchDeltaP-Stationary,
Where:
  • Srxlev = current Srxlev value of the serving cell (dB).
  • SrxlevRefStationary = reference Srxlev value of the serving cell (dB), set as follows:
    • After selecting or reselecting a new cell, or
    • If (Srxlev - Srxlev) > 0, or
    • If the relaxed measurement criterion has not been met for TSearchDeltaP-Stationary:
      • The UE shall set the value of SrxlevRefStationary to the current Srxlev value of the serving cell.
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5.2.4.9.4  Relaxed measurement criterion for a stationary (e)RedCap UE not at cell edge |R17|p. 35
The relaxed measurement criterion for a stationary (e)RedCap UE not at cell edge is fulfilled when:
  • the relaxed measurement criterion in clause 5.2.4.9.3 is fulfilled for a period of TSearchDeltaP-Stationary,
  • Srxlev > SSearchThresholdP2, and,
  • Squal > SSearchThresholdQ2, if SSearchThresholdQ2 is configured.
Where:
  • Srxlev = current Srxlev value of the serving cell (dB).
  • Squal = current Squal value of the serving cell (dB).
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5.2.4.10  Cell reselection with CAG cells |R16|p. 36

In addition to normal cell reselection, a UE may optionally use an autonomous search function to detect CAG cells on serving and non-serving frequencies. However UE shall follow the cell reselection criteria based on dedicated frequency priorities and only follow the autonomous cell search result if the result fulfils also the existing cell reselection criteria based on dedicated frequency priorities.

5.2.4.11  Reselection priorities for slice-based cell reselection |R17|p. 36

The UE derives reselection priorities for slice-based cell reselection by using:
  • NAS provided NSAG information, only for NSAG(s) associated with the network slice(s) provided by NAS for cell reselection (see TS 23.501, TS 24.501),
  • sliceInfoList and/or sliceInfoListDedicated per frequency with nsag-CellReselectionPriority per NSAG, if provided in system information and/or dedicated signalling (see TS 38.331),
  • cellReselectionPriority per frequency provided in system information and/or dedicated signalling (see TS 38.331).
The UE considers an NR frequency to support all slices of an NSAG if
  • the nsag-ID and TA of the NSAG indicated for the NR frequency (see TS 38.331) are included in the NSAG information provided by NAS. If FreqPriorityListDedicatedSlicing is configured, UE only considers the NSAG-frequency pairs indicated in FreqPriorityListDedicatedSlicing for slice-based cell reselection.
The UE considers a cell on an NR frequency to support all slices of an NSAG if
  • the nsag-ID and TA of the NSAG indicated for the NR frequency in dedicated signalling but not in SIB16 (see TS 38.331) are included in the NSAG information provided by NAS; or
  • the nsag-ID and TA of the NSAG indicated for the NR frequency in SIB16 (see TS 38.331) are included in the NSAG information provided by NAS; and
    • the cell is either listed in the sliceAllowedCellListNR (if provided in the sliceInfoList) or the cell is not listed in the sliceExcludedCellListNR (if provided in the sliceInfoList); or
    • Neither sliceAllowedCellListNR nor sliceExcludedCellListNR is configured in the sliceInfoList.
The UE shall derive reselection priorities for slice-based cell reselection according to the following rules:
  • Frequencies that support at least one prioritized NSAG received from NAS have higher reselection priority than frequencies that support none of the NSAG(s) received from NAS.
  • Frequencies that support at least one NSAG provided by NAS are prioritised in the order of the NAS-provided priority for the NSAG with highest priority supported on the frequency.
  • Among the frequencies (one or multiple) that support the highest prioritised NSAG(s) with the same NAS-provided priorities, the frequencies are prioritized in the order of their highest nsag-CellReselectionPriority given for these NSAG(s). If no nsag-CellReselectionPriority is given for a NSAG at a frequency, the lowest priority value is used (i.e, lower than any of the network configured values for these frequencies).
  • Frequencies that support none of the NSAG(s) provided by NAS are prioritized in the order of their cellReselectionPriority.
For a UE performing slice-based cell reselection, if the highest ranked cell or best cell in a frequency fulfils the inter- freqeuency cell reselection criteria (see clause 5.2.4.5) based on reselection priority for the frequency and NSAG derived according to this clause or fulfils intra-frequency and equal priority inter-frequency cell reselection criteria (see clause 5.2.4.6), but this cell does not support the NSAG according to this clause:
  • if this cell supports any other NSAG(s) according to this clause, the UE shall re-derive a reselection priority for the frequency by considering the NSAG(s) supported by this cell (rather than those of the corresponding NR frequency);
  • Otherwise, the UE shall re-derive a reselection priority for the frequency as if none of the NSAG(s) provided by NAS is supported.
This re-derived reselection priority is used for a maximum of 300 seconds, or until new network slice(s) and/or NSAG information are received from NAS. UE shall ensure the cell reselection criteria above are fulfilled based on the newly derived priorities.
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