4.23.2 List of "PLMNs not allowed to operate at the present UE location"

The UE may be rejected with 5GMM cause #78 in REGISTRATION REJECT message, SERVICE REJECT message or DEREGISTRATION REQUEST message. The 5GMM cause #78 is applicable for the UE only when the UE is accessing a 5G PLMN/access technology combination with specific satellite features.

For 3GPP satellite NG-RAN the UE shall store a list of "PLMNs not allowed to operate at the present UE location". Each entry consists of:

• the PLMN identity of the PLMN which sent a message including 5GMM cause value #78 "PLMN not allowed to operate at the present UE location" via satellite NG-RAN access technology;
• the geographical location, if known by the UE, where 5GMM cause value #78 was received on satellite NG-RAN access technology; and
• if the geographical location exists, a UE implementation specific distance value.

Before storing a new entry in the list of "PLMNs not allowed to operate at the present UE location", the UE shall delete any existing entry with the same PLMN identity. Upon storing a new entry, the UE starts a timer instance associated with the entry with an implementation specific value that shall not be set to a value smaller than the timer value indicated by the network in the Lower bound timer value IE, if any. If the Lower bound timer value IE was not provided by the network, the value of the timer shall be set based on the UE implementation.

For NG-RAN access, the UE shall store a list of "LSP PLMNs not allowed to operate at the present UE location". Each entry in the list consists of:

• PLMN identity/access technoloy combination of the PLMN which sent a message including 5GMM cause value #78 "PLMN not allowed to operate at the present UE location";
• geographical location, if known by the UE, where the 5GMM cause value #78 was received over the satellite NG-RAN access technology; and
• if the geographical location exists, a UE implementation specific distance value.

Before storing a new entry in the list of "LSP PLMNs not allowed to operate at the present UE location", the UE shall delete any existing entry with the same PLMN identity/access technology combination. Upon storing a new entry, the UE starts a timer instance associated with the entry with an implementation specific value that shall not be set to a value smaller than the timer value indicated by the network in the Lower bound timer value IE, if any. If the Lower bound timer value IE was not provided by the network, the value of the timer shall be set based on the UE implementation.

The UE is allowed to attempt to access a 5G PLMN /access technology combination with specific satellite features which is part of the list of "PLMNs not allowed to operate at the present UE location" or "LSP PLMNs not allowed to operate at the present UE location" only if:

• the current UE location is known, a geographical location is stored for the entry of this PLMN, and the distance to the current UE location is larger than a UE implementation specific value; or
• the access is for emergency services (see 3GPP TS 23.122 [5] for further details).

NOTE 1: When the UE is accessing network for emergency services, it is up to operator and regulatory policies whether the network needs to determine if the UE is in a location where network is not allowed to operate.

NOTE 2: While location determination is ongoing to ensure that operator and regulatory policies are met, the AMF can perform DNN-based or S-NSSAI based congestion control as specified in clauses 5.3.10 and 5.3.11 to prevent the UE from accessing network.

Each of the lists shall accommodate three or more entries. The maximum number of entries in each list is an implementation decision. When any of the lists is full and a new entry in the list has to be inserted, the oldest entry shall be deleted in the list.

Each entry shall be removed if for the entry:

• the UE successfully registers via a 5G PLMN/access technology combination with specific satellite features to the PLMN stored in the entry except when the UE registers for emergency services; or
• the timer instance associated with the entry expires.

The UE may delete the entry in the list of "PLMNs not allowed to operate at the present UE location", if the current UE location is known, a geographical location is stored for the entry of this PLMN, and the distance to the current UE location is larger than a UE implementation specific value.

The UE may delete the entry in the list of "LSP PLMNs not allowed to operate at the present UE location", if the current UE location is known, a geographical location is stored for the entry of this PLMN/access technology combination, and the distance to the current UE location is larger than a UE implementation specific value.

If the UE is in 5GMM-DEREGISTERED.LIMITED-SERVICE state and an entry from the lists, the UE shall perform PLMN selection according to 3GPP TS 23.122 [5].

When the UE is switched off, the UE shall keep the list of "PLMNs not allowed to operate at the present UE location" and "LSP PLMNs not allowed to operate at the present UE location" in its non-volatile memory. The UE shall delete the lists if the USIM is removed.

If the UE is switched off when the timer instance associated with the entry in the list is running, the UE shall behave as follows when the UE is switched on and the USIM in the UE remains the same:

let t1 be the time remaining for timer instance associated with the entry in the list to timeout at switch off and let t be the time elapsed between switch off and switch on. If t1 is greater than t, then the timer shall be restarted with the value t1 – t. If t1 is equal to or less than t, then the timer need not be restarted and considered expired. If the UE is not capable of determining t, then the UE shall restart the timer with the value t1.