User equipment and method for operating user equipment (UE)

Abstract

A user equipment (UE) and a method for operating a user equipment (UE) are provided. The method for operating the UE comprises the following steps: monitoring the operation of the UE; and allowing the user equipment UE to establish a new N1 Network Attachment Subsystem (NAS) signaling connection to initiate a registration procedure of the emergency service fallback procedure during the user equipment UE attempts to acquire service on a higher priority Public Land Mobile Network (PLMN).

Description

Technical Field

[0001] The present disclosure relates to a user equipment and method, and more particularly, to a user equipment and method for exempting an emergency service fallback procedure due to an unsafe SOR (Steering of Roaming). Background Art

[0002] In wireless communication technology, user equipment UE can use emergency service fallback procedures to perform emergency procedures. Support for "emergency service fallback" means that the UE falls back from 5GS (5G system, 5G system) (N1 mode) to EPS (Evolved Packet System, Evolved Packet System) (S1 mode) to obtain emergency services.

[0003] If the 5GS network indicates support for "emergency service fallback" of the TA (Tracking Area) and RAT (Radio Access Technology) where the UE is currently located, and if the UE supports "emergency service fallback", the UE shall initiate the emergency service fallback procedure to establish an emergency session.

[0004] The purpose of the control plane solution for roaming guidance in the 5GS process in the PLMN (Public Land Mobile Network) is to allow the HPLMN (Home Public Land Mobile Network) to perform one or more updates through NAS (Non Access Stratum) signaling. Summary of the invention

[0005] A simplified summary of one or more aspects is presented below to provide a basic understanding of these aspects. This summary is not a comprehensive overview of all intended aspects, and is neither intended to identify key or important elements of all aspects, nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that is presented later.

[0006] The embodiment of the present invention provides a user equipment and a method for exempting an emergency service fallback procedure due to an unsafe roaming guidance SOR.

[0007] According to an embodiment, a method for operating a user equipment UE is provided. The method for operating a UE includes: monitoring the operation of the UE; and allowing the UE to establish a new N1NAS signaling connection to initiate a registration procedure for an emergency service fallback procedure while the UE attempts to obtain service on a higher priority PLMN.

[0008] According to another embodiment, a method for operating a user equipment UE is provided. The method for operating a UE includes: monitoring the operation of the UE; and if the UE has initiated a registration procedure to perform an emergency service fallback procedure, controlling the reception of roaming guidance information to not trigger the release of the N1NAS signaling connection.

[0009] According to another alternative embodiment, a user equipment UE is provided. The UE includes a transceiver and a processor. The transceiver is configured to wirelessly communicate with a network. The processor is connected to the transceiver and configured to perform operations including: monitoring the operation of the UE; and allowing the UE to establish a new N1NAS signaling connection to initiate a registration procedure for an emergency service fallback procedure while the UE attempts to obtain service on a higher priority PLMN.

[0010] To accomplish the foregoing and related ends, the features included in one or more aspects and specifically pointed out in the claims are fully described below. The following description and the accompanying drawings set forth in detail certain illustrative features of the one or more aspects. However, these features are indicative of several of the various ways of employing the principles of the various aspects, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention may be more fully understood by reading the following detailed description and referring to the accompanying drawings, in which:

[0012] Figure 1 A schematic diagram of a mobile communication system according to an embodiment of the present disclosure is shown.

[0013] Figure 2 A flowchart of a method for operating a user equipment UE according to an embodiment of the present disclosure is shown.

[0014] Figures 3A to 3C The second stage process of guiding the user equipment UE in the VPLMN during registration according to an embodiment of the present disclosure is shown.

[0015] Figure 4 A schematic diagram of a mobile communication system according to another embodiment of the present disclosure is shown.

[0016] Figure 5 The second stage process of guiding the user equipment UE in the HPLMN or VPLMN after registration according to an embodiment of the present disclosure is shown.

[0017] Figure 6 According to one embodiment of the present disclosure, a user equipment UE is described. DETAILED DESCRIPTION

[0018] The technical terms in this specification are used in the technical field. If there is an explanation or definition of certain technical terms in this specification, the technical terms in this part will take precedence over the explanation or definition elsewhere. The present invention of each embodiment has one or more technical features. Where possible, a person of ordinary skill in the art can selectively implement some or all of the technical features of the present invention, or selectively combine these technical features of the present invention.

[0019] Please refer to Figure 1 , which shows a schematic diagram of a mobile communication system 1000 according to an embodiment of the present disclosure. The mobile communication system 1000 may be a Long Term Evolution (LTE) system, a fifth generation mobile communication technology 5G new radio (NR) system, a machine to machine (M2M) system, or a sixth generation communication system to be evolved in the future. The mobile communication system 1000 includes a user equipment (UE) 100, a base station 200, and a core network device 300. The base station 200 and the core network device 300 may be collectively referred to as network devices.

[0020] In wireless communication technology, UE 100 can use emergency service fallback procedures to perform emergency procedures. Supporting "emergency service fallback" means that UE 100 falls back from 5GS (N1 mode) to EPS (S1 mode) to obtain emergency services.

[0021] However, the behavior of the UE emergency services fallback procedure is not defined in the following cases:

[0022] (1) Whether to allow UE 100 to establish a new N1NAS signaling connection when starting the registration procedure for the purpose of emergency service fallback procedure.

[0023] (2) If the UE 100 has initiated the registration procedure for the emergency service fallback procedure, whether the UE 100 is allowed to release the N1NAS signaling connection upon receiving guidance from roaming information.

[0024] (3) If the N1NAS signaling connection is not released within the implementation dependent time, then when the UE 100 has initiated the emergency service fallback procedure, the UE 100 is allowed to locally release the N1NAS signaling connection.

[0025] To resolve these issues, some solutions are provided below. Figure 2 , which shows a flow chart of a method for operating a user equipment (UE) according to an embodiment of the present disclosure. The method for operating UE 100 includes, for example, steps S110 to S150.

[0026] In step S110, the operation of the UE 100 is monitored. Then, the process continues to step S120, step S130, step S140 and / or step S150.

[0027] In step S120, while the UE 100 attempts to acquire services on a higher priority PLMN, the UE 100 is allowed to establish a new N1NAS signaling connection to initiate a registration procedure for the emergency service fallback procedure.

[0028] In step S130, if the emergency service fallback procedure fails, the UE 100 is allowed to try to select an E-UTRA (Evolved UMTS Terrestrial Radio Access Network) cell connected to an EPC (Evolved Packet Core) or a 5GCN (5G core network).

[0029] In step S140, if the emergency service fallback procedure fails, the UE 100 is allowed to notify an upper layer of the failure of the emergency service fallback procedure.

[0030] In step S150, if the emergency service fallback procedure fails, the UE 100 is allowed to locally deregister and perform an emergency registration procedure.

[0031] For example, Figure 2 The method described in the foregoing may be implemented in the second phase procedure of directing the registration of the UE 100 during a VPLMN (Visited Public Land Mobile Network).

[0032] Please refer to FIG. 3A to FIG. 3C , which show the second stage procedure of bootstrapping a user equipment (UE) 100 in a VPLMN during registration according to one embodiment of the present disclosure.

[0033] In step S1_1, UE 100 initiates registration procedures for initial registration, emergency registration, or mobility and periodic registration updates to VPLMN AMF (Access and Mobility Management Function) by sending a REGISTRATION REQUEST message with a 5GS registration type IE, indicating "initial registration", "emergency registration" or "mobility registration update" (see 3GPP (3rd Generation Partnership Project) TS (Technical Specifications) 24.501).

[0034] In step S1_2, after receiving the REGISTRATION REQUEST message, the VPLMN AMF performs the registration procedure defined in section 4.2.2.2 of 3GPP TS 23.502.

[0035] In step S1_3a, if the user subscription information indicates guidance for sending roaming information due to initial registration in the VPLMN, the HPLMN UDM (Unified Data Management) shall provide guidance for roaming information to the UE 100 when the UE 100 performs initial registration in the VPLMN, otherwise the HPLMN UDM may provide guidance for roaming information to the UE 100 according to the operator policy.

[0036] In step S1_3b, Nsoraf_SoR_Get request (VPLMN ID (Identity document), SUPI (Subscription Permanent Identifier) ​​of UE 100, access type (see 3GPP TS29.550)).

[0037] In step S1_3c, Nsoraf_SoR_Get responds.

[0038] In step S1_3d, the HPLMN UDM forms a guide for roaming information according to the provisions of 3GPP TS 33.501.

[0039] In step S1_4, the HPLMN UDM sends a response of the Nudm_SDM_Get service operation to the VPLMN AMF, which includes the guidance of roaming information in the access and mobility subscription data.

[0040] In step S1_5, as part of the registration procedure, the VPLMN AMF also invokes the Nudm_SDM_Subscribe service operation to the HPLMN UDM to subscribe to notifications of subscription data changes (e.g., received in step 4) including notifications of guidance updates of roaming information contained in the access and mobility subscription data (see step 14c of clause 4.2.2.2.2 of 3GPP TS 23.502).

[0041] In step S1_6, the VPLMN AMF shall transparently send the received roaming information guidance to the UE 100 in a REGISTRATION ACCEPT message.

[0042] In step S1_7, if the guidance of roaming information is received and the security check is successful, then:

[0043] a) If the UDM does not require UE 100 confirmation, the UE 100 shall send a REGISTRATION COMPLETE message to the serving AMF without including a SOR transparent container;

[0044] b) If the Roaming Information Guidance contains a security package (see 3GPP TS 31.115):

[0045] If the service "Peer-to-peer data download via SMS (Short Message Service)" is allocated and activated in the USIM (Universal Subscriber Identity Module) service table (see 3GPP TS 31.102), the mobile equipment ME shall upload the security package to the USIM using the procedures in 3GPP TS 31.111;

[0046] If the UDM does not require UE 100 confirmation and:

[0047] A) When the mobile equipment ME receives a USAT REFRESH with a command qualifier (3GPP TS 31.111) of type "Roaming Steering" and contains a SOR-CMCI (Steering of Roaming Connected Mode Control Information) or the UE 100 is configured with a SOR-CMCI, the UE 100 shall perform items a), b) and c) of the Roaming Steering procedure in clause 4.4.6 and if the UE 100 is in automatic network selection mode, the actions in clause C.4.2 shall apply. In this case, steps 8 to 11 are skipped; or

[0048] B) When the ME receives a USATREFRESH with Command Qualifier (3GPP TS 31.111) Type "Roaming Guidance" and does not contain a SOR-CMCI and the UE 100 is not configured with a SOR-CMCI, it shall perform items a), b) and c) of the Roaming Guidance procedure in clause 4.4.6 and if:

[0049] i) the UE 100 has a list of available and allowed PLMNs in the area and based on this list or any other implementation specific means, the UE 100 determines that there is a PLMN with higher priority than the selected VPLMN; or

[0050] ii) the UE 100 does not have a list of available and allowed PLMNs in the area and cannot use any other implementation-specific means to determine whether there is a PLMN with higher priority than the selected VPLMN;

[0051] and the UE 100 is in automatic network selection mode, the UE 100 shall:

[0052] i) Locally release the current N1NAS signalling connection and then attempt to acquire service on a higher priority PLMN in the manner specified in clause 4.4.3.3 as if the timer T controlling the periodic attempts had expired. In this case, steps 8 to 11 are skipped. The UE 100 shall suspend sending 5GSM (5G Session Management) messages until the N1NAS signalling is released. The UE 100 shall not initiate establishment of a new N1NAS signalling connection until the attempt to acquire service on a higher priority PLMN is completed, except for the purpose of initiating a registration procedure for emergency services, establishing an emergency PDU (Protocol Data Unit) session or performing emergency services fallback. If the UE 100 has an emergency PDU session established or is performing emergency services fallback (see 3GPP TS 24.501), the received roaming guidance information shall not trigger the release of the N1NAS signalling connection. If camped in a NG-RAN (Next Generation Radio Access Network, or 5G Radio Access Network) cell, the UE 100 should subsequently locally release the current N1NAS signaling connection after the emergency PDU session is released, otherwise the UE 100 should not take any further action; or

[0053] ii) do not locally release the current N1NAS signaling connection (for example, if the UE 100 has established a PDU session), and skip steps 8 to 10;

[0054] c) If the roaming guidance information contains a preferred PLMN / access technology combination list, the ME shall replace the highest priority entry in the list of "operator-controlled PLMN selectors and access technologies" stored in the ME with the received preferred PLMN / access technology combination list, and delete the PLMNs identified by the preferred PLMN / access technology combination list from the prohibited PLMN list and the prohibited GPRS (General Packet Radio Service) service PLMN list (if they exist in these lists). In addition, if:

[0055] i) the UE 100 has a list of available and allowed PLMNs in the area and based on this list or any other implementation specific means, the UE 100 determines that there is a PLMN with higher priority than the selected VPLMN; or

[0056] ii) the UE 100 does not have a list of available and allowed PLMNs in the area and cannot use any other implementation-specific means to determine whether there is a PLMN with higher priority than the selected VPLMN;

[0057] And the UE 100 is in automatic network selection mode:

[0058] A) If the UE 100 is configured with SOR-CMCI or receives SOR-CMCI via N1NAS signaling, the UE 100 shall apply the actions in clause C.4.2. In this case, skip steps 8 to 11;

[0059] B) Otherwise, the UE 100 shall:

[0060] i) locally release the current N1NAS signalling connection and then attempt to acquire service on the higher priority PLMN in the manner specified in clause 4.4.3.3 as if the timer T controlling the periodic attempts had expired. In this case, steps 8 to 11 are skipped. The UE 100 shall suspend sending 5GSM messages until the N1NAS signalling is released. The UE 100 shall not initiate establishment of a new N1NAS signalling connection until the attempt to acquire service on the higher priority PLMN is complete, except for the purpose of initiating a registration procedure for emergency services, establishing an emergency PDU session or performing emergency services fallback. If the UE 100 has an established emergency PDU session or is performing emergency services fallback (see 3GPP TS 24.501), the received roaming guidance information shall not trigger the release of the N1NAS signalling connection. If camped on an NG-RAN cell, the UE 100 shall subsequently locally release the current N1NAS signalling connection after the emergency PDU session is released, otherwise the UE 100 shall not take any further action. If the UE 100 needs to disable the N1 mode capability (see 3GPP TS24.501) and there is no emergency service pending, the UE 100 should first try to obtain services on a higher priority PLMN as described in this step. If a higher priority PLMN cannot be selected but the last registered PLMN is selected, the UE 100 should disable the N1 mode capability; or

[0061] ii) Do not release the current N1NAS signaling connection locally (e.g. if the UE 100 has established a PDU session) and skip steps 8 to 10. When the UE 100 performs initial registration in the VPLMN or if roaming guidance information is received but the security check is unsuccessful

[0062] In step S1_8, if the USIM of UE 100 is configured with an indication that UE 100 should receive roaming guidance information due to initial registration in a VPLMN, but neither a preferred PLMN / access technology combination list nor a security data packet is received in the REGISTRATION ACCEPT message, and neither a HPLMN indication is received, i.e. "no change is required to the 'operator controlled PLMN selector and access technology' list stored in UE 100, and therefore no preferred PLMN / access technology combination list is provided", when UE 100 performs initial registration in a VPLMN or if roaming guidance information is received but the security check is unsuccessful, then UE 100 should:

[0063] a) If the REGISTRATION ACCEPT message contains a SOR (Steering of Roaming) transparent container, a REGISTRATION COMPLETE message is sent to the serving AMF without the SOR transparent container;

[0064] b) If the currently selected VPLMN is not included in the list of "PLMNs with suspended registration due to SOR" and is not part of the list of "User controlled PLMN selector and access technology" and the UE 100 is not in manual operation mode:

[0065] i) If the UE 100 receives the roaming guidance information when performing the registration procedure of mobility and periodic registration update (see 3GPP TS24.501) in the VPLMN but the security check is not successful, and the UE 100 has SOR-CMCI stored and there is an ongoing PDU session or service, the UE 100 shall act according to clause C.4.2. In this case, the current PLMN is considered to have the lowest priority and steps 9 to 11 are skipped;

[0066] ii) Otherwise, the UE 100 shall locally release the current N1NAS signalling connection and attempt to acquire service on the higher priority PLMN in the manner specified in clause 4.4.3.3 as if the timer T controlling the periodic attempts had expired; with the exception that the current PLMN is considered to be of lowest priority and steps 9 to 11 are skipped. The UE 100 shall suspend sending 5GSM messages until the N1NAS signalling is released. The UE 100 shall not initiate establishment of a new N1NAS signalling connection until the attempt to acquire service on the higher priority PLMN is completed, except for the purpose of initiating a registration procedure for emergency services, establishing an emergency PDU session or performing an emergency services fallback procedure. If the UE 100 has already established an emergency PDU session (see 3GPP TS 24.501), if camped on an NG-RAN cell, the UE 100 shall locally release the current N1NAS signalling connection after the emergency PDU session is released, otherwise the UE 100 shall not take any further action. If the UE 100 needs to disable the N1 mode capability (see 3GPP TS 24.501

[64] ) and no emergency service is pending, the UE 100 should first try to obtain service on a higher priority PLMN as described in this step. If no higher priority PLMN is available but the last registered PLMN is selected, the UE 100 should disable the N1 mode capability;

[0067] c) If the currently selected VPLMN is not included in the list of "PLMNs whose registration is suspended due to SOR", the PLMN identity is stored in the list of "PLMNs whose registration is suspended due to SOR".

[0068] In step S1_9, if the UDM has requested the UE 100 to confirm, and the UE 100 has verified in step S1_7 that the roaming guidance information is provided by the HPLMN, the UE 100 sends a REGISTRATION COMPLETE message.

[0069] In step S1_10, if a SOR transparent container is received in the REGISTRATION COMPLETE message, the AMF provides the received SOR transparent container to the UDM using the Nudm_SDM_Info service operation.

[0070] In step S1_10a, Nsoraf_SoR_Info (SUPI of UE 100, successful delivery, "ME supports SOR-CMCI" indicator (if any), "ME supports SOR-SNPN-SI (Steering of roaming SNPN selectioninformation)" indicator (if any), "ME supports SOR-SNPN-SI-LS (Steering of roaming SNPN selection information for localized services)" indicator (if any)) is provided to the SOR-AF.

[0071] In step S1_11, if the UE 100 has a list of available PLMNs, and based on this list the UE 100 determines that there is a PLMN with a higher priority than the selected VPLMN, and the UE 100 is in automatic network selection mode, then the UE 100 shall attempt to acquire service on the higher priority PLMN in the manner specified in clause 4.4.3.3, as if the timer T controlling the periodic attempts has expired, after the N1NAS signalling connection is released.

[0072] In step S1_12, if the registration procedure is aborted due to SOR, the UE 100 may delete the PLMN list.

[0073] Please refer to Figure 4 , which shows a schematic diagram of a mobile communication system according to another embodiment of the present disclosure. The method for operating a user equipment (UE) 100 includes, for example, steps S210 to S260.

[0074] In step S210, the operation of the UE 100 is monitored. Then, the process continues to step S220, step S230, step S240, step S250 and / or step S260.

[0075] In step S220, if the UE 100 has started the registration procedure of the emergency service fallback procedure, the receiving of the roaming guidance information is controlled so as not to trigger the release of the N1NAS signaling connection.

[0076] In step S230, if the UE 100 has initiated the registration procedure for the emergency service fallback procedure, the expiration of the timer is controlled so as not to trigger the release of the N1NAS signaling connection.

[0077] In step S240, if the UE 100 has started the registration procedure for the emergency service fallback procedure, the UE 100 is allowed to attempt to select an E-UTRA cell connected to the EPC or 5GCN.

[0078] In step S250, if the UE 100 has started the registration procedure of the emergency service fallback procedure, the UE 100 is allowed to notify the upper layer of the failure of the emergency service fallback procedure.

[0079] In step S260, if the UE 100 has started the registration procedure of the emergency service fallback procedure, the UE 100 is allowed to locally deregister and perform the emergency registration procedure.

[0080] For example, Figure 4 The method described in the specification may be implemented in a second phase procedure of bootstrapping a user equipment (UE) 100 in a HPLMN or a VPLMN after registration.

[0081] Please refer to Figure 5 , which shows a second stage procedure of bootstrapping a user equipment (UE) 100 in a HPLMN or a VPLMN after registration according to one embodiment of the present disclosure.

[0082] In step S2_1, a Nudm_ParameterProvision_Update request is sent to the HPLMN UDM to trigger the update of the UE 100 with a new preferred PLMN / access technology combination list, SOR-CMCI (if any) and "Store SOR-CMCI in ME" indicator (if any) or a security data package provisioned for the UE 100 identified by the SUPI.

[0083] In step S2_2, the UDM notifies the affected AMF of the changes to the user profile by calling the Nudm_SDM_Notification service operation.

[0084] In step S2_3, the AMF sends a DL NAS TRANSPORT message to the served UE 100.

[0085] In step S2_4, after receiving the roaming guidance information, the UE 100 shall perform a security check on the roaming guidance information contained in the DL NAS TRANSPORT message to verify that the roaming guidance information is provided by the HPLMN, and:

[0086] If the security check is successful and:

[0087] a) If the Roaming Guidance message contains a security data packet (see 3GPP TS 31.115

[67] ) and the service "Peer to Peer Data Download via SMS" is allocated and activated in the USIM service table (see 3GPP TS 31.102

[40] ), the ME shall upload the security data packet to the USIM using the procedures in 3GPP TS 31.111

[41] .

[0088] If the UDM requested confirmation from the UE 100 in the DL NAS TRANSPORT message and the ME received a UICC (Universal Integrated Circuit Card) response indicating that the UICC has successfully received the security package, the UE 100 sends a UL NAS TRANSPORT message to the serving AMF, containing the UE 100 confirmation and the UE 100:

[0089] The "ME supports SOR-CMCI" indicator in the SOR transparent container header should be set to "supported";

[0090] If the UE 100 supports accessing a SNPN (Stand-alone Non-Public Network) using credentials from the credential holder, the "ME Supports SOR-SNPN-SI" indicator of the SOR transparent container header may be set to "Supported"; and

[0091] If the UE 100 supports access to SNPNs that provide localized services in SNPNs, the "ME supports SOR-SNPN-SI-LS" indicator in the SOR transparent container header shall be set to "Supported"; and

[0092] When the ME receives a USAT REFRESH command qualifier of type "Roaming Guidance" (see 3GPP TS 31.111

[41] ) and neither contains a SOR-CMCI nor is SOR-CMCI configured, it performs the Roaming Guidance procedure as described in clause 4.4.6, with one exception, if the UE 100 is in automatic network selection mode, the UE 100 shall wait until it moves to idle mode or 5G MM (5GS mobility management)-CONNECTED mode with an RRC (Radio Resource Control) inactivity indication (see 3GPP TS 24.501

[64] ) before attempting to acquire service on a higher priority PLMN (as described in clause 4.4.6 bullet d); or

[0093] When the ME receives a USAT REFRESH command qualifier of type "Roaming Guidance" (see 3GPP TS 31.111

[41] ) and contains a SOR-CMCI or the UE 100 is configured with a SOR-CMCI, the UE 100 shall perform items a), b) and c) of the Roaming Guidance procedure as described in clause 4.4.6. If the UE 100 is in automatic network selection mode, it shall apply the operations in clause C.4.2;

[0094] b) If the roaming guidance information contains a list of preferred PLMN / access technology combinations, the ME shall replace the highest priority entry in the list of "Operator controlled PLMN selectors and access technologies" stored in the ME with the received list of preferred PLMN / access technology combinations and remove the PLMNs identified by the list of preferred PLMN / access technology combinations from the forbidden PLMN list and the forbidden PLMN list for GPRS service, if they are present in these lists.

[0095] If the UDM requested confirmation from the UE 100 in the DL NAS TRANSPORT message, the UE 100 sends a UL NAS TRANSPORT message to the serving AMF, which contains the UE 100 confirmation and the UE 100:

[0096] The "ME supports SOR-CMCI" indicator should be set to "Supported"

[0097] If the UE 100 supports access to the SNPN using credentials from the credential holder, the "ME supports SOR-SNPN-SI" indicator of the SOR transparent container header may be set to "Supported"; and

[0098] If the UE 100 supports access to a SNPN providing localized services in the SNPN, the "ME supports SOR-SNPN-SI-LS" indicator of the SOR transparent container header shall be set to "Supported".

[0099] If the UE 100 is in automatic network selection mode and the selected PLMN is a VPLMN, then:

[0100] If the UE 100 has stored the SOR-CMCI or received the SOR-CMCI via N1NAS signalling, the UE 100 shall apply the operations in clause C.4; or

[0101] The UE 100 shall wait until it moves to IDLE mode or 5G MM-CONNECTED mode with an RRC Inactivity Indication (see 3GPP TS 24.501

[64] ) before attempting to acquire service on a higher priority PLMN, as described in clause 4.4.3.3, behaving as if the timer T controlling the periodic attempts has expired. The UE 100 shall not initiate establishment of a new N1 NAS signalling connection until the attempt to acquire service on a higher priority PLMN is completed, except for the purpose of initiating emergency services, emergency services fallback or establishing an emergency PDU session.

[0102] If the selected PLMN is a VPLMN and the UE 100 has established an emergency PDU session, then if the UE 100 is in automatic network selection mode, the UE 100 should attempt to perform PLMN selection after the emergency PDU session is released.

[0103] If the UDM does not request confirmation from the UE 100, then step 5 is skipped; and

[0104] If the selected PLMN is a VPLMN, the security check is unsuccessful and the UE 100 is in automatic network selection mode, then:

[0105] If the UE 100 has stored the SOR-CMCI, the current PLMN is considered as the lowest priority and the UE 100 shall apply the operations in clause C.4.2; or

[0106] If there is an ongoing PDU Session or Service, the UE 100 shall apply the operations in clause C.4.2; or

[0107] The UE 100 shall locally release the current N1NAS signalling connection and attempt to acquire service on the higher priority PLMN, behaving as if the timer T controlling the periodic attempts has expired, as described in clause 4.4.3.3. The UE 100 shall not initiate establishment of a new N1NAS signalling connection until the attempt to acquire service on the higher priority PLMN is completed, except for the purpose of initiating emergency services, establishing an emergency PDU session or performing emergency services fallback;

[0108] If the UE 100 does not store the SOR-CMCI, then:

[0109] If there is an ongoing PDU Session or service, the UE 100 shall wait until it moves to IDLE mode or 5G MM-CONNECTED mode with an RRC INACTIVE indication (see 3GPP TS 24.501

[64] ) before attempting to acquire service on a higher priority PLMN, as described in clause 4.4.3.3, behaving as if the timer T controlling the periodic attempts had expired, with the exception that the current PLMN is considered to be the lowest priority. The UE 100 shall not initiate establishment of a new N1NAS signalling connection until the attempt to acquire service on a higher priority PLMN is completed, except for the purpose of initiating emergency services, establishing an emergency PDU Session or performing emergency services fallback. If the selected PLMN is a VPLMN and the UE 100 has established an emergency PDU Session, the UE 100 shall attempt to perform PLMN selection after the emergency PDU Session is released; or

[0110] If there is no ongoing PDU Session or service, the User Equipment UE 100 shall locally release the current N1NAS signalling connection and attempt to acquire service on a higher priority PLMN as specified in clause 4.4.3.3, behaving as if the timer T controlling the periodic attempts had expired, with the exception that the current PLMN is considered to be the lowest priority. The UE 100 shall not initiate the establishment of a new N1NAS signalling connection until the attempt to acquire service on a higher priority PLMN is completed, except for the purpose of initiating a registration procedure for emergency services, establishing an emergency PDU Session or performing emergency services fallback.

[0111] In step S2_5, if a UL NAS transport message with a SOR transparent container is received, the AMF provides the received SOR transparent container to the UDM using the Nudm_SDM_Info service operation.

[0112] In step S2_6, Nsoraf_SoR_Info (SUPI of UE 100, successfully delivered, indication of “ME supports SOR-CMCI”, if any, indication of “ME supports SOR-SNPN-SI”, if any, indication of “ME supports SOR-SNPN-SI-LS”, if any).

[0113] Figure 6 A user equipment (UE) 100 according to an embodiment of the present disclosure is shown. The user equipment 100 can perform various functions to implement the schemes, technologies, processes and methods related to UE behavior in mobile communications described herein, including various schemes of various proposed designs, concepts, schemes, systems and methods described above, including network environments, and the processes described below.

[0114] UE 100 may be part of an electronic device, which may be a network device, such as a portable or mobile device, a wearable device, an in-vehicle device or vehicle, a wireless communication device, or a computing device. For example, UE 100 may be implemented in a smartphone, a smart watch, a personal digital assistant, an electronic control unit (ECU) in a vehicle, a digital camera, or a computing device, such as a tablet, a laptop, or a notebook computer. The user device may also be part of a machine type device, which may be an IoT device, such as a fixed or static device, a home device, a roadside unit (RSU), a wired communication device, or a computing device. For example, UE 100 may be implemented in a smart thermostat, a smart refrigerator, a smart door lock, a wireless speaker, or a home control center. When implemented in or as a network device, UE 100 may be implemented in an eNodeB in an LTE (Long Term Evolution), LTE-Advanced, or LTE-Advanced Pro network, or in a gNB or TRP (Transmission and Receiving Point) in a 5G network, an NR network, or the Internet of Things.

[0115] In some embodiments, UE 100 may be implemented in the form of one or more integrated circuit (IC) chips, such as, but not limited to, one or more single-core processors, one or more multi-core processors, one or more complex instruction set computing (CISC) processors, or one or more reduced instruction set computing (RISC) processors. In the above various schemes, UE 100 may be implemented in or as a network device. UE 100 may include Figure 41 , such as processor 110, transceiver 120, and memory 130. UE 100 may also include one or more other components not related to the solution proposed in the present disclosure (e.g., internal power supply, display device, and / or user interface device).

[0116] In one aspect, the processor 110 may be implemented in the form of one or more single-core processors, one or more multi-core processors, or one or more CISC or RISC processors. That is, even though the singular term "a processor" is used herein to refer to the processor 110, in some embodiments, the processor 110 may include multiple processors, and in other embodiments may include a single processor, in accordance with the present disclosure. In another aspect, the processor 110 may be implemented in the form of hardware (and, optionally, firmware), including electronic components, such as, but not limited to, one or more transistors, one or more diodes, one or more capacitors, one or more resistors, one or more inductors, one or more memristors, and / or one or more variable capacitors, which are configured and arranged in accordance with the present disclosure to achieve a specific purpose. In other words, in at least some embodiments, the processor is a special-purpose machine specifically designed, arranged, and configured to perform specific tasks, including those UE 100 behaviors related to failed registration and emergency service fallback service requests in mobile communications in various embodiments of the present disclosure.

[0117] The transceiver 120 is connected to the processor 110. The transceiver 120 can transmit and receive data wirelessly. In some embodiments, the transceiver 120 can wirelessly communicate with different radio access technologies (RATs) of different wireless networks. In some embodiments, the transceiver 120 may be equipped with multiple antenna ports (not shown), for example, four antenna ports. That is, the transceiver 120 may be equipped with multiple transmit antennas and multiple receive antennas for multiple input multiple output (MIMO) wireless communication.

[0118] The memory 130 is connected to the processor 110 and stores data therein. The memory 130 may include a random access memory (RAM), such as a dynamic RAM (DRAM), a static RAM (SRAM), a thyristor RAM (T-RAM) and / or a zero capacitance RAM (Z-RAM). Alternatively, the memory 113 may include a read-only memory (ROM), such as a mask ROM, a programmable ROM (PROM), an erasable programmable ROM (EPROM) and / or an electrically erasable programmable ROM (EEPROM). Alternatively, the memory 130 may include a non-volatile random access memory (NVRAM), such as a flash memory, a solid-state memory, a ferroelectric RAM (FeRAM), a magnetoresistive RAM (MRAM) and / or a phase change memory.

[0119] The processor 110 of the UE 100 is configured to perform the operations described above.

[0120] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is an illustration of an exemplary method. It should be understood that the specific order or hierarchy of the blocks in the process / flowchart may be rearranged based on design preferences. In addition, some blocks may be combined or omitted. The accompanying method claims present the elements of the various blocks in an example order and are not intended to be limited to the specific order or hierarchy presented.

[0121] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Therefore, the claims are not intended to be limited to the various aspects shown herein, but should be given a full scope consistent with the claims text, wherein unless explicitly stated, the reference to the elements in the singular form is not intended to represent "one and only one", but to represent "one or more". The word "exemplary" is used herein to represent "used as an example, instance or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as being preferred or advantageous over other aspects. Unless otherwise explicitly stated, the term "some" refers to one or more. Combinations such as "at least one of A, B or C", "one or more of A, B or C", "at least one of A, B and C", "one or more of A, B and C" and "A, B, C or any combination thereof" include any combination of A, B and / or C, and may include multiple A, multiple B or multiple C. Specifically, phrases such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be only A, only B, only C, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents of the elements throughout the various aspects of the description of the present invention that are known or will later be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, regardless of whether such disclosure is expressly recited in the claims, nothing disclosed herein is intended to be dedicated to the public. The terms "module," "mechanism," "element," "device," and the like may not replace the term "device." Therefore, unless a claim element is expressly recited using the phrase "device for...", no claim element should be interpreted as a device plus function.

Claims

1. A method for operating a user equipment UE, characterized in that: include: monitoring the operation of the UE; as well as The UE is allowed to establish a new N1 mode non-access stratum N1 NAS signaling connection to initiate a registration procedure for an emergency service fallback procedure while the UE attempts to acquire service on a higher priority public land mobile network PLMN.

2. The method according to claim 1, characterized in that Further including: In the event that the emergency service fallback procedure fails, the UE is allowed to attempt to select an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRA) cell connected to the Evolved Packet Core Network (EPC) or the 5G Core Network (5GCN).

3. The method according to claim 1, characterized in that Further including: In the event that the emergency service fallback procedure fails, the UE is allowed to notify an upper layer of the failure of the emergency service fallback procedure.

4. The method according to claim 1, characterized in that Further including: In case the emergency service fallback procedure fails, the UE is allowed to locally deregister and perform an emergency registration procedure.

5. A method for operating a user equipment UE, characterized in that: include: monitoring the operation of the UE; as well as If the UE has initiated a registration procedure for an emergency service fallback procedure, receiving a roaming guidance message is controlled to not trigger a release of an N1 NAS signaling connection.

6. The method according to claim 5, characterized in that Further including: If the UE has initiated the registration procedure to perform the emergency service fallback procedure, an expiration of a timer is controlled to not trigger a release of an N1 NAS signaling connection.

7. The method according to claim 5, characterized in that Further including: If the UE has initiated the registration procedure to perform the emergency service fallback procedure, the UE is allowed to attempt to select an E-UTRA cell connected to the EPC or 5GCN.

8. The method according to claim 5, characterized in that Further including: If the UE has initiated the registration procedure to perform the emergency service fallback procedure, the UE is allowed to notify the upper layer of the failure of the emergency service fallback procedure.

9. The method according to claim 5, characterized in that Further including: If the UE has initiated the registration procedure to perform the emergency service fallback procedure, the UE is allowed to locally deregister and perform an emergency registration procedure.

10. A user equipment, characterized in that: include: a transceiver configured to communicate wirelessly with a network; as well as A processor connected to the transceiver and configured to perform an operation: monitoring the operation of the UE; as well as The UE is allowed to establish a new N1NAS signaling connection to initiate a registration procedure for an emergency service fallback procedure while the UE attempts to acquire service on a higher priority PLMN.

11. The user equipment according to claim 10, characterized in that The operation further includes: In the event that the emergency services fallback procedure fails, the UE is allowed to attempt to select an E-UTRA cell to connect to the EPC or 5GCN.

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