Content for  TS 38.304  Word version:  18.0.0

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 and NCR-MTs.

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. This field is ignored by UEs supporting NTN while cellBarredNTN is included in SIB1.
• cellBarredATG (IE type: "barred" or "not barred")
  Indicated in SIB1 message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is common for all PLMNs and NPNs. This field is only applicable to ATG UEs.
• cellBarred-eRedCap1Rx (IE type: "barred" or "not barred")
  Indicated in SIB1 message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is common for all PLMNs and NPNs. This field is only applicable to eRedCap UEs.
• cellBarred-eRedCap2Rx (IE type: "barred" or "not barred")
  Indicated in SIB1 message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is common for all PLMNs and NPNs. This field is only applicable to eRedCap UEs.
• cellBarredNES (IE type: "not barred")
  Indicated in SIB1 message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is common for all PLMNs and NPNs. This field is only applicable to UEs capable of NES cell DTX/DRX.
• cellBarredNTN (IE type: "barred" or "not barred")
  Indicated in SIB1 message. In case of multiple PLMNs indicated in SIB1, this field is common for all PLMNs. This field is ignored if the UE does not support NTN connectivity.
• cellBarredRedCap1Rx (IE type: "barred" or "not barred")
  Indicated in SIB1 message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is common for all PLMNs and NPNs. This field is only applicable to RedCap UEs.
• cellBarredRedCap2Rx (IE type: "barred" or "not barred")
  Indicated in SIB1 message. In case of multiple PLMNs or NPNs indicated in SIB1, this field is common for all PLMNs and NPNs. This field is only applicable to RedCap UEs.
• 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.
• halfDuplexRedCapAllowed (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. This field is only applicable to (e)RedCap UEs.
• 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.
• ncr-Support (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.
• mobileIAB-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,

• 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 cellBarredNES is absent and cellBarred is set to "barred",

• The UE capable of NES cell DTX/DRX shall treat this cell as if cell status is "barred".

When cellBarredNTN is not broadcast in this cell,

• For NTN access, the UE shall treat this cell as if cell status is "barred".

When halfDuplexRedCapAllowed is not broadcast in this cell,

• The (e)RedCap UE only capable of operating in half-duplex for FDD shall treat this cell as if cell status is "barred".

When cellBarredATG is not broadcast in this cell,

• For ATG access, 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.
• UEs assigned to Access Identity 3 shall behave as if the cell status is "barred" in case the cell is "reserved for operator use" for the registered PLMN or the selected PLMN.

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 UE is a RedCap UE, the UE shall acquire SIB1 and, in the remainder of this procedure, consider 'intraFreqReselection in MIB' to be 'intraFreqReselectionRedCap in SIB1', if available;
  • If the UE is an eRedCap UE, the UE shall acquire SIB1 and, in the remainder of this procedure, consider 'intraFreqReselection in MIB' to be 'intraFreqReselection-eRedCap in SIB1', if available.
    • If the cell is to be treated as if the cell status is "barred" due to being unable to acquire the SIB1:
      • 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.
    • If the cell status "barred" is indicated in MIB but the UE is unable to acquire the SIB1; or
    • If the cell is to be treated as if the cell status is "barred" due to not supporting (e)RedCap UEs:
      • the UE shall exclude the barred cell as a candidate for cell selection/reselection for 300 seconds.
      • the UE may select another cell on the same frequency if re-selection criteria are fulfilled.
  • If the UE is neither a RedCap UE nor an eRedCap UE, or if the UE is a RedCap UE and intraFreqReselectionRedCap in SIB1 is available, or if the UE is an eRedCap UE and intraFreqReselection-eRedCap in SIB1 is available:
    • 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;
      • If the cell is to be treated as if the cell status is "barred" due to being unable to acquire the SIB1:
        • the UE may exclude the barred cell as a candidate for cell selection/reselection for up to 300 seconds;
      • else:
        • 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 is to be treated as if the cell status is "barred" due to being unable to acquire the SIB1:
        • the UE may exclude the barred cell as a candidate for cell selection/reselection for up to 300 seconds;
        • If the cell operates in licensed spectrum:
          • the UE shall not re-select to another cell on the same frequency as the barred cell and exclude such cell(s) as candidate(s) for cell selection/reselection for 300 seconds;
        • else:
          • the UE may select to another cell on the same frequency if the reselection criteria are fulfilled.
      • else:
        • 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 the selected PLMN of the UE, or if this cell belongs to an SNPN which is equal to or indicated as being equivalent to the registered SNPN or the selected SNPN of the UE:
          • the UE shall not re-select to another cell on the same frequency as the barred cell and exclude such cell(s) as candidate(s) for cell selection/reselection for 300 seconds;
        • else:
          • the UE may select to another cell on the same frequency if the reselection criteria are fulfilled.
        • the UE shall exclude the barred cell as a candidate for cell selection/reselection for 300 seconds.

The cell selection of another cell may also include a change of RAT.

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. A L2 U2N Relay UE does not need to perform the Unified Access Control as specified in TS 38.331, due to the U2N Remote UE access attempt.