Mediatek Corporation

Yuan-chieh Lin

Chia-Lin Lai

Chien-chun Huang-fu

Pan-Yen Chiang

Chi-Hsien Chen

Yu-Chieh Tien

Chien-Chun Huang Fu

A method of determining UE access identity for a UE that is registered to the same or different PLMN networks over 3GPP and non-3GPP accesses is proposed. The UE registers to one or more Public Land Mobile Network (PLMN) or Standalone Non-Public Network (SNPN) over 3GPP access and non-3GPP access. If the UE registers to the same PLMN/SNPN over 3GPP and non-3GPP access, then the UE handles the UE access identity as one common parameters. On the other hand, if the UE registers to different PLMN/SNPN over 3GPP and non-3GPP, then the UE handles the UE access identity as two independent parameters. The access identity may comprise a priority indicator IE that is set to 'Access Identity 1 valid' for MPS or “Access Identity 2 valid” for MCS.

UE access identity determination for 3GPP and non-3GPP accesses

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.

Multiple previously registered networks for network selection

A method of handling NAS signaling connection release under mobility management congestion control for MUSIM UE is proposed. A MUSIM UE has established a NAS signaling connection on a first USIM in connected mode. Later on, the MUSIM UE has more important job to be started on the second USIM. The MUSIM UE wishes to initiate a service request procedure by transmitting a service request to the network, to release the NAS signaling connection on the first USIM. However, under the 5GMM/EMM signaling congestion condition with timer T3346 running, the AMF/MME rejects 5GMM/EMM signaling requests from UE. In one novel aspect, the MUSIM UE requests the network to release the NAS signaling connection while timer T3346 is still running. As a result, the MUSIM UE is able to start the more important job on the second USIM, or to improve user experience on the second USIM.

MUSIM SR procedure and MM congestion control

A method of determining paging restriction on downlink signals for MUSIM UEs is proposed. If a UE requests the network to support paging restriction over the first USIM, the UE can send a request message to the network, carrying a UE-preferred paging restriction information. Subsequently, the UE should then receive an accept message from the network that the paging is restricted over the first USIM based on the UE-preferred paging restriction information. As a result, when DL signaling is pending for the UE over the first USIM, the network can determine whether it should page the UE over the first USIM based on the paging restriction type indicated in the paging restriction information. Since the DL signaling is selectively restricted over USIM1, the UE can perform more important jobs over USIM2 with better performance and user experience.

MUSIM paging restriction in 5GS

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.

UE auto update cag configuration when accessing pni-npn as hosting network for localized services

A method for handling a collision of a UE-requested PDU session establishment procedure and a network-requested PDU session modification procedure is proposed. When a PDU SESSION ESTABLISHMENT REQUEST message indicates that the UE-requested PDU session establishment request procedure is to handover an existing PDU session between 5G 3GPP access and 5G non-3GPP access, UE and NW proceed with the UE-requested PDU session establishment procedure and abort the NW-requested PDU session modification procedure. When a PDU SESSION ESTABLISHMENT REQUEST message indicates that the UE-requested PDU session establishment request procedure is to establish user plane resources for an MA PDU session, UE and NW proceed with both the UE-requested PDU session establishment procedure and the NW-requested PDU session modification procedure.

Handling of collision between PDU session establishment and modification procedure

A method of handling parameters of a subscribed network upon accessing a selected Stand-alone Non-Public Network (SNPN) using credentials from a credential holder is proposed. The UE selects an SNPN using a configured list of subscriber data, e.g., based on SNPN selection parameters contained in a selected entry of the list of subscriber data, or selects the SNPN based on SNPN selection parameters associated with a PLMN subscription of a USIM card. The UE accesses the selected SNPN using credentials supplied by a subscribed network, which is identified by the selected entry or by the USIM card. Upon successful registration to the selected SNPN, the UE applies a list of 3GPP PS_Data_Off exempt services that is different from a configured list of 3GPP PS_Data_Off exempt services associated with the selected entry, and evaluates a URSP that is different from the pre-configured URSP of the subscribed network.

Parameters handling for SNPN-enabled UE

A method of handling (alternative) IMSI value for MUSIM UEs supporting paging timing collision control in an EPS network is proposed. For a MUSIM UE and EPS supporting paging timing collision control, the MUSIM UE and the network can request and negotiate an IMSI offset for the IMSI value on one of the USIM card through a TAU or ATTACH procedure. When lower layer failure occurs, the network may not successfully receive a TRACKING AREA UPDATE COMPLETE (or ATTACH COMPLETE) message from the UE, and therefore the network may not know which IMSI value UE will use. Accordingly, the network needs to use both possible (alternative) IMSI values when deriving paging timing for the UE until one of the (alternative) IMSI values is considered invalid.

MUSIM IMSI offset value handling for paging timing collision control

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.

PEIPS applicability considering non-3GPP registration

A method to establish and activate an MA PDU session for data transmission over a selected access is proposed. UE initiates a UE-requested PDU session establishment procedure. Once the UE receives a PDU SESSION ESTABLISHMENT ACCEPT message with ATSSS container IE, the UE can consider the MA PDU session has been activated and user plane resources are successfully established on the selected access. A method to convert an SA PDU session to an MA PDU session for data transmission over a selected access is proposed. UE initiates a UE-requested PDU session modification procedure. Once the UE receives a PDU SESSION MODIFICATION COMMAND message with ATSSS container IE, the UE can consider the MA PDU session has been converted from the SA PDU session and user plane resources are successfully established on the selected access.

MA PDU session and user plane resource establishment for data transmission

A method of handling authentication reject upon accessing an SNPN using credentials from a credential holder is proposed. A UE is configured with a 'list of subscriber data'. The UE selects an SNPN using the configured list of subscriber data, e.g., based on the SNPN selection parameters contained in a selected entry of the list of subscriber data. Based on the selected entry, the UE selects an SNPN, and then tries to access the selected SNPN using credentials supplied by a subscribed SNPN. When UE receives an authentication reject message from the network, UE considers that the selected entry of the list of subscriber data is invalid. However, other entries related to the current selected SNPN are still valid. UE is still able to access the current selected SNPN, using credentials supplied in another entry of the list of subscriber data.

Authentication reject handling for SNPN-enabled UE

A method supporting enhanced network identity (NID) provisioning under User Equipment (UE) mobility scenarios between different types of networks is proposed. When a UE registers to an SNPN, the UE is assigned with a 5G-GUTI by the SNPN. The SNPN is identified by an SNPN ID==PLMN ID+NID. When the UE moves from the SNPN to another target network having a target AMF, the UE triggers a mobility registration update procedure and provides the 5G-GUTI along with NID information in a Registration Request to the target AMF. The target AMF can use the NID information along with the 5G-GUTI to find a source AMF for deriving UE context for the subsequent operations during the mobility registration update procedure. Providing NID information along with 5G-GUTI can assist the target AMF to find the source AMF efficiently, preventing a potential registration procedure failure.

NID provisioning under UE mobility scenarios

A method of enhanced handling of a Forbidden SNPN list by a UE is proposed. When the UE registers to a first SNPN using credentials supplied by a second SNPN and receives a rejection from the network, the UE adds an entry of the first SNPN into one of the forbidden SNPN lists, and also creates an association between the first SNPN and the second SNPN. As a result, the UE is refrained from registering to the first SNPN using the credentials supplied by the second SNPN as long as the first SNPN entry remains in the forbidden SNPN list. However, the UE is allowed to register to the first SNPN using credentials supplied by other SNPNs.

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Hsin-Chu, Taiwan

Yuan-chieh Lin