5.30.2.4.2 Automatic network selection

NOTE 1: If the UE has multiple subscriptions (SNPN and/or PLMN) it is assumed that the subscription to use for automatic selection is determined by implementation specific means prior to network selection.

If the UE supports accessing an SNPN providing access for Localized Services and the end user enables to access Localized Services, for automatic network selection, the UE shall select and attempts registration on available SNPN in the following order:

(a) if the UE supports access to an SNPN using Credentials from a Credentials Holder then the UE continues by selecting and attempting registration on available and allowable SNPNs which broadcasts the indication that access using credentials from a Credentials Holder is supported in the following order:

i the SNPN with the validity information the UE was last registered with (if the validity information is met) or the SNPN's equivalent SNPN(s) (if available and the validity information of the SNPN that the UE was last registered with is met);

NOTE 2: The equivalent SNPN(s) are assumed to provide access to the same Localized Services as the SNPN the UE was last registered with.

ii SNPNs in the Credentials Holder controlled prioritized list of preferred SNPNs for accessing Localized Services (in priority order) if the validity information is met;

iii SNPNs, which additionally broadcast a GIN contained in the Credentials Holder controlled prioritized list of preferred GINs for accessing Localized Services (in priority order) if validity information is met;

(b) the SNPN without validity information the UE was last registered with (if available) or the equivalent SNPN (if available);

(c) the subscribed SNPN, which is identified by the PLMN ID and NID for which the UE has SUPI and credentials;

(d) the available and allowable SNPNs which broadcast the indication that access using credentials from a Credentials Holder is supported in the following order:

i SNPNs in the user controlled prioritized list of preferred SNPNs (in priority order);

ii SNPNs in the Credentials Holder controlled prioritized list of preferred SNPNs (in priority order);

iii SNPNs, which additionally broadcast a GIN contained in the Credentials Holder controlled prioritized list of preferred GINs (in priority order);

iv- SNPNs, which additionally broadcast an indication that the SNPN allows registration attempts from UEs that are not explicitly configured to select the SNPN, i.e. the broadcasted NID or GIN is not present in the Credentials Holder controlled prioritized lists of preferred SNPNs/GINs, nor in the Credentials Holder controlled prioritized lists of preferred SNPNs/GINs for accessing Localized Services in the UE.

If the location validity information is not available and the time validity information is available, the validity conditions are met when the time validity conditions are met. If both the location validity information and the time validity information are available, the validity conditions are met when both the time validity conditions and the location validity conditions are met.

If the UE supports accessing an SNPN providing access for Localized Services and the end user enables to access Localized Services, the UE shall periodically attempt reselection and registration on a higher priority SNPN 1) based on the order of the above sub-bullets (i) to (iii) of bullet (a), bullet (c), sub-bullets (i) to (iii) of bullet (d) if the UE is not registered to the sub-bullet (i) of bullet (a) or 2) based on the order of the above sub-bullets (ii) to (iii) of bullet (a), bullet (c), sub-bullets (i) to (iii) of bullet (d) if the UE is registered to the sub-bullet (i) of bullet (a) if any of the below conditions is met:

• if there are one or more SNPNs with validity information which is met and the UE is not registered to an SNPN which has highest priority among the one or more SNPNs; or
• if there is no SNPN with validity information which is met and there are one or more GINs with the validity information which is met and the UE is not registered to an SNPN broadcasting a GIN which has highest priority among the one or more GINs; or
• if there is no SNPN with validity information which is met and there is no GIN with validity information which is met and the UE is not registered to the subscribed SNPN

Otherwise, the UE does not trigger periodic reselection and does not attempt registration on a higher priority SNPN.

NOTE 3: Details of network selection (e.g. validity information handling, periodicity determination) specified in TS 23.122 [17].

If the selected SNPN is an SNPN providing access for Localized Services and the validity condition for the selected SNPN changes from met to not met, the UE may attempt selection and registration on an SNPN based on the above bullets (a) to (d).

If the selected SNPN is not an SNPN providing access for Localized Services and a validity condition for an entry in Credentials Holder controlled prioritized list of preferred SNPNs/GINs for accessing Localized Services changes from not met to met, the UE may attempt selection and registration on an SNPN based on the above bullets (a) to (d).

If the UE does not support to access an SNPN providing access for Localized Services or the end user does not enable to access the Localized Services, for automatic network selection the UE shall select and attempts registration on available and allowable SNPNs in the following order:

• the SNPN without validity information the UE was last registered with (if available) or the equivalent SNPN (if available);
• the subscribed SNPN, which is identified by the PLMN ID and NID for which the UE has SUPI and credentials;
• If the UEs supports access to an SNPN using credentials from a Credentials Holder then the UE continues by selecting and attempting registration on available and allowable SNPNs which broadcast the indication that access using credentials from a Credentials Holder is supported in the following order:
• SNPNs in the user controlled prioritized list of preferred SNPNs (in priority order);
• SNPNs in the Credentials Holder controlled prioritized list of preferred SNPNs (in priority order);
• SNPNs, which additionally broadcast a GIN contained in the Credentials Holder controlled prioritized list of preferred GINs (in priority order);

NOTE 4: If multiple SNPNs are available that broadcast the same GIN, the order in which the UE selects and attempts a registration with those SNPNs is implementation specific.

• SNPNs, which additionally broadcast an indication that the SNPN allows registration attempts from UEs that are not explicitly configured to select the SNPN, i.e. the broadcasted NID or GIN is not present in the Credentials Holder controlled prioritized lists of preferred SNPNs/GINs in the UE.

NOTE 5: If multiple SNPNs are available that broadcast the indication that the SNPN allows registration attempts from UEs that are not explicitly configured to select the SNPN, the order in which the UE selects and attempts a registration with those SNPNs is implementation specific.

When a UE performs Registration or Service Request to an SNPN, the UE shall indicate the PLMN ID and NID as broadcast by the selected SNPN to NG-RAN. NG-RAN shall inform the AMF of the selected PLMN ID and NID.