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Content for  TS 38.304  Word version:  16.2.0

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5.3  Cell Reservations and Access Restrictions

5.3.0  Introduction

There are two mechanisms which allow an operator to impose cell reservations or access restrictions. The first mechanism uses indication of cell status and special reservations for control of cell selection and reselection procedures. The second mechanism, referred to as Unified Access Control as specified in TS 38.331, shall allow preventing selected access categories or access identities from sending initial access messages for load control reasons.
Unified Access Control does not apply to IAB-MTs.
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5.3.1  Cell status and cell reservations

Cell status and cell reservations are indicated in the MIB or SIB1 message as specified in TS 38.331 by means of following fields:
  • cellBarred (IE type: "barred" or "not barred")
    Indicated in MIB message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is common for all PLMNs and NPNs
  • cellReservedForOperatorUse (IE type: "reserved" or "not reserved")
    Indicated in SIB1 message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is specified per PLMN or per SNPN.
  • cellReservedForOtherUse (IE type: "true")
    Indicated in SIB1 message. In case of multiple PLMNs indicated in SIB1, this field is common for all PLMNs.
  • cellReservedForFutureUse (IE type: "true")
    Indicated in SIB1 message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is common for all PLMNs and NPNs.
  • iab-Support (IE type: "true")
    Indicated in SIB1 message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is specified per PLMN or per SNPN.
When cell status is indicated as "not barred" and "not reserved" for operator use and not "true" for other use and not "true" for future use,
  • All UEs shall treat this cell as candidate during the cell selection and cell reselection procedures.
When cell broadcasts any CAG-IDs or NIDs and the cell status is indicated as "not barred" and "not reserved" for operator use and "true" for other use, and not "true" for future use:
  • All NPN-capable UEs shall treat this cell as candidate during the cell selection and cell reselection procedures, other UEs shall treat this cell as if cell status is "barred".
When cell status is indicated as "true" for other use, and either cell does not broadcast any CAG-IDs or NIDs or does not broadcast any CAG-IDs and the UE is not operating in SNPN Access Mode,
  • The UE shall treat this cell as if cell status is "barred".
When cell status is indicated as "true" for future use,
  • The UE shall treat this cell as if cell status is "barred".
When cell status is indicated as "not barred" and "reserved" for operator use for any PLMN/SNPN and not "true" for other use and not "true" for future use,
  • UEs assigned to Access Identity 11 or 15 operating in their HPLMN/EHPLMN shall treat this cell as candidate during the cell selection and reselection procedures if the field cellReservedForOperatorUse for that PLMN set to "reserved".
  • UEs assigned to Access Identity 11 or 15 shall treat this cell as candidate during the cell selection and reselection procedures if the field cellReservedForOperatorUse for selected/registered SNPN is set to "reserved".
  • UEs assigned to an Access Identity 0, 1, 2 and 12 to 14 shall behave as if the cell status is "barred" in case the cell is "reserved for operator use" for the registered PLMN/SNPN or the selected PLMN/SNPN.
When cell status "barred" is indicated or to be treated as if the cell status is "barred",
  • The UE is not permitted to select/reselect this cell, not even for emergency calls.
  • The UE shall select another cell according to the following rule:
  • If the cell is to be treated as if the cell status is "barred" due to being unable to acquire the MIB:
    • the UE may exclude the barred cell as a candidate for cell selection/reselection for up to 300 seconds.
    • the UE may select another cell on the same frequency if the selection criteria are fulfilled.
  • else:
    • If the field intraFreqReselection in MIB message is set to "allowed", the UE may select another cell on the same frequency if re-selection criteria are fulfilled;
    • The UE shall exclude the barred cell as a candidate for cell selection/reselection for 300 seconds.
    • If the field intraFreqReselection in MIB message is set to "not allowed":
      • If the cell operates in licensed spectrum or if this cell belongs to a PLMN which is indicated as being equivalent to the registered PLMN or if this cell belongs to the registered SNPN of the UE:
        • the UE shall not re-select a cell on the same frequency as the barred cell;
      • else:
        • the UE may select to another cell on the same frequency if reselection criteria are fulfilled.
      • The UE shall exclude the barred cell and, if the cell operates in licensed spectrum or if this cell belongs to a PLMN which is indicated as being equivalent to the registered PLMN, also the cells on the same frequency as a candidate for cell selection/reselection for 300 seconds.
The cell selection of another cell may also include a change of RAT.
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5.3.2  Unified access controlWord‑p. 33
The information on cell access restrictions associated with Access Categories and Identities is broadcast in SIB1 as part of Unified Access Control as specified in TS 38.331.
The UE shall ignore Access Category and Identity related cell access restrictions for cell reselection. A change of the indicated access restriction shall not trigger cell reselection by the UE.
The UE shall consider Access Category and Identity related cell access restrictions for NAS initiated access attempts and RNAU as specified in TS 38.331.
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5.4  Tracking Area registration

In the UE, the AS shall report tracking area information to the NAS.
If the UE reads more than one PLMN identity in the current cell, the UE shall report the found PLMN identities that make the cell suitable in the tracking area information to NAS.
If the UE operating in SNPN access mode reads more than one SNPN identity in the current cell, the UE shall report the found SNPN identities that make the cell suitable in the tracking area information to NAS.
The NAS part of the location registration process is specified in TS 23.122.
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5.5  RAN Area registration

The UE performs a RAN-based notification area update (RNAU) periodically or when the UE selects a cell that does not belong to the configured RNA.

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