Abstract: A method of handling deregistration procedure with updated a CAG related configuration is proposed. From the network perspective, an AMF receives a DEREGISTRATION REQUEST message from a UE in a CAG cell that broadcasts a list of supported CAG-IDs. The AMF determines that a CAG-ID is supported by the CAG cell and included in the CAG related configuration of the UE. However, the CAG-ID is associated with validity or restriction information, and the corresponding validity or restriction criteria are not met. In response to the UE-initiated DEREGISTRATION REQUEST message, the AMF initiates a de-registration procedure and send a network-initiated DEREGISTRATION REQUEST message to the UE, including a 5GMM cause value. The network-initiated DEREGISTRATION REQUEST message can also include the updated CAG related configuration for UE. Upon receiving the DEREGISTRATION REQUEST message, the UE can update the UE-maintained CAG related configuration accordingly.

Abstract: A method of forbidden SNPN list handling for localized services is provided. In a first embodiment, an original forbidden SNPN list is maintained and is applicable for SNPN/GIN without validity information, and a new forbidden SNPN list is maintained and is applicable for SNPN/GIN with validity information for localized services. If a selected SNPN is associated with validity information, then UE checks whether the selected SNPN belongs to the new forbidden SNPN list. In a second embodiment, the original forbidden SNPN list is maintained and is extended with optional localized service Flag/Indication. Each entry in the original forbidden SNPN list can be associated with an optional localized service Flag or Indication. If a selected SNPN is associated with validity information, then UE checks whether the selected SNPN belongs to the original forbidden SNPN list with a localized service Flag/Indication.

Abstract: A method of a UE determining whether a current camped CAG cell is suitable and thereby entering limited service state for PNI-NPN as a hosting network is provided. When the PNI-NPN is a hosting network providing localized services, one or more allowed CAG IDs are associated with validity information per UE stored configuration, e.g., time and/or location validity criteria. Once a CAG cell is selected and camped by the UE in a PLMN, the UE needs to consider whether the current CAG cell is suitable for obtaining normal service from the PLMN. If the hosting network functionality is not enabled (by user), or if the time and/or location validity criteria associated with CAG-IDs broadcasted by the current CAG cell are not met, then the current CAG cell is not suitable. As a result, the UE enters limited service state, and triggers cell reselection or PLMN selection procedure.

Abstract: A method of handling a service request from a UE camped on a CAG cell with emergency PDU session is proposed, where the UE is not authorized to access the current CAG cell. When the UE-maintained CAG related configuration is not synchronized with the NW-maintained CAG related configuration, the UE may try to access a CAG cell and sends a service request, but the NW may determine that the CAG cell is not suitable. Because the UE has an existing emergency PDU session, the network will accept the service request, and locally releases all non-emergency PDU sessions associated with 3GPP access. Specifically, the network will locally release SA non-emergency PDU sessions associated with 3GPP access, or MA PDU sessions with only 3GPP access user-plane resources, or 3GPP user-plane resources of MA PDU sessions with both 3GPP and non-3GPP access user-plane resources.

Abstract: In accordance with one novel aspect, a method of handling updated a CAG related configuration and in response perform a NAS procedure for releasing NAS connection is proposed. While camping on a CAG cell, during a NAS procedure, a UE receives a DL NAS message from AMF that carries validity or restriction information associated with a CAG-ID for the current PLMN and the CAG-ID is supported by the current CAG cell and included in the DL NAS message, and the validity or restriction criteria are not met according to the validity or restriction information. The UE starts a timer to allow the AMF to release the NAS connection. The UE locally releases the NAS connection upon timer expiry.

Abstract: A method of backoff timer handling for accessing a hosting network for localized services is proposed. When a UE receives a NAS message from an NPN hosting network with a backoff timer, the UE needs to determine whether it can register to the NPN as a hosting network for localized services while the backoff timer is running. The UE checks the validity information associated with the NPN, e.g., an SNPN/GIN/CAG, and determines whether the UE is still authorized to access the NPN upon/after backoff timer expiry. In one example, if the current time+the remaining length/duration of the backoff timer is longer than the end of the validity time of the NPN, then the UE triggers the network selection (SNPN selection or PLMN selection) and registers to another PLMN, PNI-NPN/CAG or SNPN for access for localized services, or just for normal services (non-localized services).

Abstract: A method of handling updated CAG related configuration is proposed. UE receives an updated CAG related configuration in a DL NAS message via a CAG cell, which broadcasts a list of supported CAG-IDs of the current network. UE may also receive an updated CAG related configuration in a DL NAS message via a non-CAG cell of the current network. The UE examines the list of allowed CAG-IDs in the updated CAG related configuration, determines whether they are supported by the CAG cell, whether they are associated with validity information, whether the validity criteria are met, whether the UE is ONLY allowed to access 5GS via CAG cells, and whether the UE has any emergency PDU session. Depending on the determination, the UE then either enters LIMITED-SERVICE and search for suitable cell in the current network, or enters PLMN-SEARCH state and applies PLMN selection process.

Abstract: A method of enhanced manual network selection procedure for access localized services in PNI-NPN is proposed. For manual CAG/PNI-NPN selection as hosting network, if a CAG cell in a PLMN broadcasting a CAG-ID is available and included in the (Allowed) CAG-ID list of the UE-stored CAG related configuration of the PLMN, the user may manually select the CAG cell as a suitable cell. However, the CAG-ID that is associated with validity information, and the corresponding validity criteria may or may not be satisfied, e.g., due to the UE-stored CAG related configuration is different from the NW-maintained CAG related configuration. Therefore, the UE does not know whether the CAG cell is suitable. In response, the UE triggers a registration procedure for mobility and periodic registration update, and obtains the updated CAG related configuration.

Abstract: A method of UE autonomously updating a CAG related configuration upon receiving a downlink NAS message is provided. If a CAG-ID is included in an allowed CAG-IDs list of the CAG related configuration and is supported by a CAG cell in a PLMN, then UE may attempt to access the CAG cell in the PLMN. If the access is denied, e.g., UE receives a DL NAS message with a cause value, then UE needs to update the CAG related configuration. If the CAG-ID is not associated with any validity or restriction information, then the CAG-ID should be deleted from the CAG related configuration. If the CAG-ID is associated with validity or restriction information and corresponding validity or restriction criteria are not met, then the CAG-ID should not be deleted from the CAG related configuration.

Abstract: In accordance with one novel aspect, a method for storing multiple previously registered networks for network selection is proposed. A UE is first registered to a first SNPN or PNI-NPN(CAG)/PLMN as a non-hosting network. The UE is then registered to a second SNPN or PNI-NPN(CAG)/PLMN as a hosting network with matching validity information. When the second SNPN or PNI-NPN(CAG)/PLMN becomes non suitable, e.g., the validity criteria associated with the second SNPN/CAG are not met, the UE considers the first SNPN or PNI-NPN(CAG)/PLMN with the highest priority and registers to the first SNPN or PNI-NPN(CAG)/PLMN without searching and prioritizing other candidate networks.

Abstract: A method for PLMN selection when UE supports accessing CAG/PNI-NPN as hosting network for localized services is proposed. When a UE is registered to a first PLMN as a non-hosting network, a cell of a second PLMN may become available for localized service. The UE can select and register to a second PLMN as a hosting network even if the second PLMN has a lower PLMN priority than the first PLMN based on traditional PLMN priority order. If multiple PLMNs are available for localized services, then the UE can select and register to a PLMN based on priority information for hosting network. The priority information for hosting network can be 1) reusing traditional PLMN priority order; 2) a new configuration for hosting network selection priority; 3) based on validity information.

Abstract: A method of handling updated CAG related configuration is proposed. UE receives an updated CAG related configuration in a DL NAS message via a CAG cell, which broadcasts a list of supported CAG-IDs of the current network. UE may also receive an updated CAG related configuration in a DL NAS message via a non-CAG cell of the current network. The UE examines the list of allowed CAG-IDs in the updated CAG related configuration, determines whether they are supported by the CAG cell, whether they are associated with validity information, whether the validity criteria are met, whether the UE is ONLY allowed to access 5GS via CAG cells, and whether the UE has any emergency PDU session. Depending on the determination, the UE then either enters LIMITED-SERVICE and search for suitable cell in the current network, or enters PLMN-SEARCH state and applies PLMN selection process.

Abstract: A method of determining suitable cell for cell selection or reselection for PNI-NPN (as hosting network) for accessing Localized services is provided. When the PNI-NPN is (a hosting network) providing access for Localized services, one or more allowed CAG IDs are associated with validity or restriction information per UE stored configuration, e.g., time and/or location validity or restriction information. The UE needs to determine whether a CAG cell broadcasting a CAG-ID is suitable by checking the validity or restriction criteria according to the validity or restriction information of the CAG-ID stored in the UE.

Abstract: A method of enhanced manual network selection mode for access localized services in NPN is proposed. If an SNPN is available and included in the UE-stored configuration for SNPN selection, the UE presents to the user whether the SNPN is associated with validity information and whether the corresponding validity criteria are met. If a CAG cell in a PLMN broadcasting a CAG-ID is available and included in the (Allowed) CAG list of the UE-stored CAG related configuration of the PLMN, the UE presents to the user whether the CAG-ID is associated with validity information and whether the corresponding validity criteria are met, e.g., whether the CAG-ID is authorized based on the (Allowed) CAG list.

Abstract: A method of periodically attempting to access the HPLMN or an EHPLMN with higher priority in NTN systems with discontinuous coverage is proposed. A UE registered in VPLMN starts a timer T to periodically attempt to obtain service on its HPLMN or EHPLMN. When access stratum is deactivated due to discontinuous coverage in NTN, the UE does not stop the timer T, and postpone the periodic attempts to a later time, e.g., upon or after the UE activates the access stratum.

Abstract: Examples pertaining to selection of a tracking area identifier (TAI) as a last visited registered TAI in a geographical location in mobile communications are described. A user equipment (UE) receives broadcast information from a network indicating a plurality of tracking area codes (TACs) for the network. The UE then determines one or more candidate TACs, including at least a first TAC, best representing a current geographical location of the UE from the plurality of TACs received by removing zero, one or more TACs of the plurality of TACs from consideration based on the broadcast information received over time.

Abstract: A method of handling lower layer failure when assigning a Paging Early Indication with Paging Subgrouping (PEIPS) subgroup ID is proposed. If a network supports and accepts the use of PEIPS assistance information for a UE, the network can provide to the UE the negotiated PEIPS assistance information containing a new Paging subgroup ID and a new 5G-GUTI in a REGISTRATION ACCEPT message or in a CONFIGURATION UPDATE COMMAND message, and the UE was assigned with an old paging subgroup ID. When lower layer failure occurs, the network may not successfully receive a REGISTRATION COMPLETE message or a CONFIGURATION UPDATE COMPLETE message from the UE. Accordingly, the network needs to use both possible paging subgroup IDs for the UE until one of the paging subgroup IDs is considered invalid.

Abstract: A method for expedited tunnel establishment with a non-Third Generation Partnership Project (3GPP) interworking gateway to access a 3GPP network is provided. A User Equipment (UE) initiates establishment of an Internet Protocol secure (IPsec) tunnel with a first non-3GPP interworking gateway associated with the 3GPP network. The UE probes availability of a second non-3GPP interworking gateway associated with the 3GPP network before the IPsec tunnel with the first non-3GPP interworking gateway is established successfully. The UE initiates establishment of an IPsec tunnel with the second non-3GPP interworking gateway in response to failing to establish the IPsec tunnel with the first non-3GPP interworking gateway and the second non-3GPP interworking gateway being available. The UE accesses the 3GPP network over the IPsec tunnel with the second non-3GPP interworking gateway.

Abstract: Aspects of the disclosure provide methods and apparatuses. The method can include receiving, at a user equipment (UE), system information broadcast from one or more base stations which may be shared by one or more PLMNs and/or one or more SNPNs, the system information including an indication of whether accessing an SNPN using home service provider (HSP) subscription of a HSP network is supported. The UE can be configured with subscription information of the HSP network. The subscription information can include the HSP subscription and a selection list that includes one or more candidate networks each represented by an SNPN identifier. The method can further include responsive to the system information, selecting a network from the selection list according to a priority order of the candidate networks, and accessing the network selected from the selection list using the HSP subscription.

Abstract: A method of handling Paging Early Indication with Paging Subgrouping (PEIPS) assistance information when a UE is registered to the same or different PLMN/SNPN networks is proposed. The PEIPS assistance information includes PEIPS parameters such as a PEIPS subgroup ID that is used by the UE for monitoring paging with PEIPS for power saving. If the UE registers to the same PLMN/SNPN via 3GPP access and non-3GPP access, then the UE handles the PEIPS parameters as one common parameters. If the UE registers to different PLMN/SNPN via 3GPP access and non-3GPP access, then the UE handles the PEIPS parameters as two independent parameters.