Radio Station, UE, and Method

Abstract

One aspect of the present disclosure includes a radio station: the radio station transmits a setup request message to a first core network node in a first network, the setup request message including information about a list of connected networks; the radio station receives a setup response message from the first core network node, the setup response message including at least one of information about a list of roaming networks and information about a priority of the roaming networks; the radio station detects a failure of a connection between the first core network node or another core network node in the first network; and the radio station transmits at least one of information related to a disaster state of the first network, information about the first network, information about the list of roaming networks, and information about a priority of the roaming networks to a wireless terminal.

Description

[Technical Field]

[0001] The present disclosure relates to a method for a radio station, a method for a core network node, a method for a radio terminal, a radio station, a core network node, and a radio terminal. [Background technology]

[0002] According to 3GPP (Third Generation Partnership Project) (registered trademark) contribution SP-220938 (Patent Document 2), 3GPP defines two new service requirements for minimizing service interruptions in the event of a core network failure.

[0003] 3GPP TS 22.261 (Patent Document 6) incorporates the following new service requirements: Issues regarding Visited Public Land Mobile Network (VPLMN) selection by Internet of things (IOT) devices are summarized below. In the case of a Radio Access Network (RAN) shared between participating PLMNs under regulatory requirements or operator policy, the 3GPP system shall be able to support a UE of a given PLMN to obtain connectivity services (e.g., voice calls, mobile data services) from another participating network when a disaster condition applies to the UE's PLMN. Subject to regulatory requirements, operator policy, or UE capabilities, the 3GPP system shall be able to support UEs to obtain 4G connectivity services (e.g., voice calls, mobile data services) from a VPLMN in areas where disaster conditions apply, using 5G-only national roaming access to that VPLMN. To meet these requirements, 3GPP specifications need to be enhanced. [Prior art documents] [Non-patent literature]

[0004] [Non-licensed Document 1] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".V17.1.0(2021-12) [Non-licensed Document 2] SP-220938: https: / / www.3gpp.org / ftp / tsg_sa / TSG_SA / TSGS_97E_Electronic_2022-09 / Docs / SP-220938.zip [Non-licensed Document 3] 3GPP TS 23.501: "System architecture for the 5G System(5GS)".V18.0.0(2022-12) [Non-licensed Document 4] 3GPP TS 23.502: "Procedures for the 5G System(5GS)".V18.0.0(2022-12) [Non-licensed Document 5] 3GPP TS 23.503: "Policy and charging control framework for the 5G System(5GS)Stage 2".V18.0.0(2022-12) [Non-licensed Document 6] 3GPP TS 22.261: "Service requirements for the 5G system Stage 1".V19.0.0(2022-09) [Non-licensed Document 7] 3GPP TS 24.501: "Non-Access-Stratum(NAS)protocol for 5G System(5GS)Stage 3".V18.1.0(2022-12) [Non-licensed Document 8] 3GPP TS 38.413: "NG-RAN; NG Application Protocol (NGAP)".V17.2.0(2022-09) [Non-licensed Document 9] 3GPP TS 38.331: “NR;Radio Resource Control (RRC) protocol specification”.V17.2.0(2022-09) [Non-Patent Document 10] 3GPP TS 23.401: “General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access”.V17.6.0 (2022-09) [Non-Patent Document 11] 3GPP TS 23.632: “User data interworking, coexistence and migration;Stage 2”.V17.3.0(2022-09) [Non-Patent Document 12] 3GPP TS 33.210: “Network Domain Security;IP network layer security”.V17.1.0(2022-09) Summary of the Invention [Problem to be solved by the invention]

[0005] In 5G systems, it is important to guarantee the availability of communication services. 3GPP TS 22.261 (Patent Document 6) emphasizes the need for disaster mitigation services when a 5G system cannot provide services to its users due to a RAN failure. 3GPP TS 22.261 (Patent Document 6) also specifies requirements for disaster roaming, in which users subject to a disaster condition roam to another PLMN to resume connectivity and service. However, it does not cover requirements for supporting communication services under core network failure.

[0006] To mitigate 5G system service disruptions, the following new service requirements for disaster roaming need to be added to 3GPP-based mobile communication systems: - In the case of a RAN shared between participating PLMNs, subject to regulatory requirements or operator policy, the 3GPP system shall be able to support a UE of a given PLMN to obtain connectivity services (e.g., voice calls, mobile data services) from another participating network when a disaster condition applies to the UE's PLMN. [Means for solving the problem]

[0007] In a first exemplary aspect, a wireless station includes: Memory and configured to access memory, Sending a setup request message to a first core network node in the first network, the setup request message including information about a list of connected networks; receiving a setup response message from a first core network node, the setup response message including at least one of information about a list of roaming networks and information about a priority of the roaming networks; Detecting a failure in a connection between the first core network node or another core network node in the first network; and at least one processor configured to transmit to the wireless terminal at least one of information related to a disaster state of the first network, information about the first network, information about a list of roaming networks, and information about a priority of the roaming networks.

[0008] In a second exemplary aspect, a first core network node in a first network comprises: Memory and configured to access memory, receiving a setup request message from the wireless station, the setup request message including information about a list of connected networks; and at least one processor configured to transmit a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about a priority of the disaster roaming networks.

[0009] In a third exemplary aspect, a wireless terminal comprises: Memory and configured to access memory, receiving at least one of information related to a disaster state of the first network, information about the first network, information about a list of roaming networks, and information about a priority of the roaming networks from the wireless station; and at least one processor configured to send a registration request message having parameters used to initiate disaster roaming services to a second core network node in the roaming network.

[0010] In a fourth exemplary aspect, a method for a wireless station includes: means for transmitting a setup request message to a first core network node in a first network, the setup request message including information about a list of connected networks; means for receiving a setup response message from a first core network node, the setup response message including at least one of information about a list of roaming networks and information about a priority of the roaming networks; means for detecting a failure of a connection between the first core network node or another core network node in the first network; and means for transmitting at least one of information related to the disaster state of the first network, information about the first network, information about a list of roaming networks, and information about a priority of the roaming networks to the wireless terminal.

[0011] In a fifth exemplary aspect, a method for a first core network node in a first network includes: means for receiving a setup request message from a wireless station, the setup request message including information about a list of connected networks; and means for transmitting a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about priorities of the disaster roaming networks.

[0012] In a sixth exemplary aspect, a method for a wireless terminal includes: means for receiving from the wireless station at least one of information related to a disaster state of the first network, information about the first network, information about a list of roaming networks, and information about a priority of the roaming networks; and means for sending a registration request message having parameters used to initiate disaster roaming services to a second core network node in the roaming network.

[0013] In a seventh exemplary aspect, a first core network node in a first network comprises: Memory and configured to access memory, receiving a setup request message from the wireless station, the setup request message including information about a list of connected networks; transmitting a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about priorities of the disaster roaming networks; receiving information from a second core network node in the first network indicating a need for minimizing service interruptions; and at least one processor configured to transmit information including at least one of a new cause parameter, a disaster status indication parameter, and an available service parameter to the wireless station.

[0014] In an eighth exemplary aspect, a method for a first core network node in a first network includes: means for receiving a setup request message from a wireless station, the setup request message including information about a list of connected networks; means for transmitting a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about priorities of the disaster roaming networks; means for receiving information from a second core network node in the first network indicating a need for minimizing service interruption; and means for transmitting information including at least one of a new cause parameter, a disaster status indication parameter, and an available service parameter to the wireless station.

[0015] In a ninth exemplary aspect, a wireless terminal comprises: Memory and configured to access memory, Decided to provide disaster-related roaming services, transmitting a Radio Resource Control (RRC) Setup Request message to the wireless station, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; receiving at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks from the wireless station; transmitting an RRC setup complete message to the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has the capability to support disaster-related roaming services, and information related to a disaster state of the first network; transmitting information related to the roaming network to the wireless station; and at least one processor configured to transmit to the wireless terminal Non Access Stratum (NAS) container information including registration request information including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to the disaster condition of the first network.

[0016] In a tenth exemplary aspect, a wireless station comprises: Memory and configured to access memory, receiving a Radio Resource Control (RRC) setup request message from the wireless terminal, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; transmitting at least one of information related to a disaster state of the first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks to the wireless terminal; receiving an RRC setup complete message from the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has capability to support disaster-related roaming services, and information related to a disaster state of the first network; receiving information related to a roaming network from the wireless terminal; receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; and at least one processor configured to transmit a registration request message to a third core network node in the roaming network (PLMN2), the registration request message including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to the disaster state of the first network.

[0017] In an eleventh exemplary aspect, a fourth core network node in a first network (PLMN1) associated with a disaster comprises: Memory and configured to access memory, receiving a message from a third core network node in the roaming network, the message including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; receiving a message from a third core network node, the message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster condition of the first network; and at least one processor configured to send a message including the subscriber data to a third core network node.

[0018] In a twelfth exemplary aspect, a third core network node in the second network: Memory and configured to access memory, receiving a registration request message from the wireless terminal, the registration request message including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to a disaster condition of the first network; transmitting a message to a fourth core network node in the first network related to the disaster, the message including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster state of the first network; transmitting a message to a fourth core network node, the message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster condition of the first network; and at least one processor configured to receive a message including the subscriber data from the fourth core network node.

[0019] In a thirteenth exemplary aspect, a method for a wireless terminal comprises: A means for determining whether to provide disaster-related roaming services; means for transmitting a Radio Resource Control (RRC) Setup Request message to a wireless station, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; means for receiving from the wireless station at least one of information related to a disaster state of the first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; means for transmitting an RRC setup complete message to the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has a capability to support disaster-related roaming services, and information related to a disaster state of the first network; means for transmitting information related to a roaming network to a wireless station; and means for transmitting Non Access Stratum (NAS) container information to the wireless station, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to the disaster condition of the first network.

[0020] In a fourteenth exemplary aspect, a method for a wireless station includes: means for receiving, from the wireless terminal, a Radio Resource Control (RRC) setup request message including information indicating that the wireless terminal has capability to support disaster-related roaming services; means for transmitting at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of roaming networks to the wireless terminal; means for receiving an RRC setup complete message from the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has a capability to support disaster-related roaming services, and information related to a disaster state of the first network; means for receiving information relating to a roaming network from a wireless terminal; means for receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; and means for transmitting a registration request message to a third core network node in the roaming network, the registration request message including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to the disaster state of the first network.

[0021] In a fifteenth exemplary aspect, a method for a fourth core network node in a first network associated with a disaster includes: means for receiving, from a third core network node in the roaming network, a message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster condition of the first network; means for receiving, from a third core network node, a message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster condition of the first network; and means for transmitting a message including the subscriber data to a third core network node.

[0022] In a sixteenth exemplary aspect, a method for a third core network node in a second network includes: means for receiving, from the wireless terminal, a registration request message including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; means for transmitting a message to a fourth core network node in the first network related to the disaster, the message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster state of the first network; means for transmitting to a fourth core network node a message including at least one of information indicating that the wireless terminal has a capability to support disaster related roaming services and information related to a disaster state of the first network; and means for receiving a message including the subscriber data from the fourth core network node.

[0023] In a seventeenth exemplary aspect, a wireless terminal comprises: Memory and configured to access memory, Decided to provide disaster-related roaming services, transmitting a Radio Resource Control (RRC) re-establishment request message to the wireless station, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; receiving at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks from the wireless station; transmitting an RRC setup complete message to the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has the capability to support disaster-related roaming services, and information related to a disaster state of the first network; transmitting information related to the roaming network to the wireless station; and at least one processor configured to transmit to the wireless terminal Non Access Stratum (NAS) container information including registration request information including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to the disaster condition of the first network.

[0024] In an eighteenth exemplary aspect, a wireless station comprises: Memory and configured to access memory, receiving a Radio Resource Control (RRC) re-establishment request message from the wireless terminal, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; transmitting at least one of information related to a disaster state of the first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks to the wireless terminal; receiving an RRC setup complete message from the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has capability to support disaster-related roaming services, and information related to a disaster state of the first network; receiving information related to a roaming network from the wireless terminal; receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; and at least one processor configured to transmit a registration request message to a third core network node in the roaming network, the registration request message including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to the disaster state of the first network.

[0025] In a nineteenth exemplary aspect, a method for a wireless terminal comprises: A means for determining whether to provide disaster-related roaming services; means for transmitting a Radio Resource Control (RRC) re-establishment request message to the wireless station, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; means for receiving from the wireless station at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; means for transmitting an RRC setup complete message to the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has a capability to support disaster-related roaming services, and information related to a disaster state of the first network; means for transmitting information related to a roaming network to a wireless station; and means for transmitting Non Access Stratum (NAS) container information to the wireless station, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to the disaster condition of the first network.

[0026] In a twelfth exemplary aspect, a method for a wireless station includes: means for receiving, from the wireless terminal, a Radio Resource Control (RRC) re-establishment request message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; means for transmitting at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of roaming networks to the wireless terminal; means for receiving an RRC setup complete message from the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has capability to support disaster related roaming services, and information related to a disaster state of the first network; means for receiving information relating to a roaming network from a wireless terminal; means for receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; and means for transmitting a registration request message to a third core network node in the roaming network (PLMN2), the registration request message including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to the disaster state of the first network. [Effects of the Invention]

[0027] According to the present disclosure, it is possible to provide a radio station, a core network node, a radio terminal, a radio station method, a core network node method, and a radio terminal method. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a signaling diagram of a first example of the first embodiment. [Figure 2]FIG. 10 is a signaling diagram of a second example of the first embodiment. [Figure 3] FIG. 10 is a signaling diagram of a third example of the first embodiment. [Figure 4] FIG. 10 is a signaling diagram of a fourth example of the first embodiment. [Figure 5] FIG. 10 is a signaling diagram of a first example of the second embodiment. [Figure 6] 10 is a diagram illustrating an example data structure in an RRC message according to a second example of the second aspect. [Figure 7] 10 is a third example subscriber data backup configuration of the second embodiment. [Figure 8] FIG. 10 is a diagram showing the relationship of backup user identification information in a third example of the second aspect. [Figure 9] FIG. 10 is a signaling diagram of a third example of the second embodiment. [Figure 10] FIG. 10 is a signaling diagram of a third example of the second embodiment. [Figure 11] FIG. 10 is a signaling diagram of a third example of the second embodiment. [Figure 12] FIG. 10 is a signaling diagram of a third example of the second embodiment. [Figure 13] FIG. 1 is a diagram illustrating an example of a system overview. [Figure 14] FIG. 1 is a block diagram illustrating a UE. [Figure 15] FIG. 1 is a block diagram illustrating an (R)AN node. [Figure 16] FIG. 1 illustrates a system overview of an (R)AN node based on an O-RAN architecture. [Figure 17] FIG. 1 is a block diagram illustrating an RU. [Figure 18] FIG. 2 is a block diagram illustrating a DU. [Figure 19] FIG. 2 is a block diagram illustrating a CU. [Figure 20] FIG. 1 is a block diagram illustrating an AMF. [Figure 21] FIG. 1 is a block diagram illustrating a PCF. [Figure 22] FIG. 1 is a block diagram illustrating an AUSF. [Figure 23] FIG. 1 is a block diagram illustrating a UDM. [Figure 24] FIG. 1 is a block diagram illustrating an NSSF. DETAILED DESCRIPTION OF THE INVENTION

[0029] (abbreviation) For the purposes of this document, 3GPP TR 21.905 and the abbreviations given below apply. An abbreviation defined in this document takes precedence over the definition of the same abbreviation in 3GPP TR 21.905, if any. 4G-GUTI 4G Globally Unique Temporary UE Identity 5GC 5G Core Network 5GLAN 5G Local Area Network 5GS 5G System 5G-AN 5G Access Network 5G-AN PDB 5G Access Network Packet Delay Budget 5G-EIR 5G-Equipment Identity Register 5G-GUTI 5G Globally Unique Temporary Identifier 5G-BRG 5G Broadband Residential Gateway 5G-CRG 5G Cable Residential Gateway 5G GM 5G Grand Master 5G-RG 5G Residential Gateway 5G-S-TMSI 5G S-Temporary Mobile Subscription Identifier 5G VN 5G Virtual Network 5QI 5G QoS Identifier AF Application Function AMF Access and Mobility Management Function AMF-G Geographically selected Access and Mobility Management Function AMF-NG Non-Geographically selected Access and Mobility Management Function ANDSF Access Network Discovery and Selection Function ARFCN Absolute radio-frequency channel number AS Access Stratum ASN Abstract Syntax Notation ATSSS Access Traffic Steering,Switching,Splitting ATSSS-LL ATSSS Low-Layer AuC Authentication Centre AUSF Authentication Server Function AUTN Authentication token BCCH Broadcast Control Channel BMCA Best Master Clock Algorithm BSF Binding Support Function CAG Closed Access Group CAPIF Common API Framework for 3GPP northbound APIs CHF Charging Function CN PDB Core Network Packet Delay Budget CP Control Plane DAPS Dual Active Protocol Stacks DL Data Network DN Data Network DNAI DN Access Identifier DNN Data Network Name DRX Discontinuous Reception DS-TT Device-side TSN translator ePDG evolved Packet Data Gateway EBI EPS Bearer Identity EPS Evolved Packet System EUI Extended Unique Identifier FAR Forwarding Action Rule FN-BRG Fixed Network Broadband RG FN-CRG Fixed Network Cable RG FN-RG Fixed Network RG FQDN Fully Qualified Domain Name GFBR Guaranteed Flow Bit Rate GMLC Gateway Mobile Location Centre GPSI Generic Public Subscription Identifier GUAMI Globally Unique AMF Identifier GUTI Globally Unique Temporary UE Identity HPLMN Home Public Land Mobile Network HR Home Routed(ローミング) HSS Home Subscriber Server HTTP Hypertext Transfer Protocol IAB Integrated access and backhaul IPsec Internet Protocol Security IMEI / TAC IMEI Type Allocation Code IMSI International Mobile Subscriber Identity IPUPS Inter PLMN UP Security I-SMF Intermediate SMF I-UPF Intermediate UPF LADN Local Area Data Network LBO Local Break Out(ローミング) LMF Location Management Function LoA Level of Automation LPP LTE Positioning Protocol LRF Location Retrieval Function MCC Mobile country code MCX Mission Critical Service MDBV Maximum Data Burst Volume ME Mobile Equipment MFBR Maximum Flow Bit Rate MICO Mobile Initiated Connection Only MINT Minimization of service interruption MITM Man In the Middle MME Mobility Management Entity MNC Mobile Network Code MPS Multimedia Priority Service MPTCP Multi-Path TCP Protocol MT Mobile Termination N3IWF Non-3GPP InterWorking Function N3GPP Non-3GPP access N5CW Non-5G-Capable over WLAN NAI Network Access Identifier NAS Non-Access-Stratum NEF Network Exposure Function NF Network Function NGAP Next Generation Application Protocol NID Network identifier NPN Non-Public Network NR New Radio NSAG Network Slice Access Stratum Group NRF Network Repository Function NSI ID Network Slice Instance Identifier NSSAA Network Slice-Specific Authentication and Authorization NSSAAF Network Slice-Specific Authentication and Authorization Function NSSAI Network Slice Selection Assistance Information NSSF Network Slice Selection Function NSSP Network Slice Selection Policy NSSRG Network Slice Simultaneous Registration Group NW-TT Network-side TSN translator NWDAF Network Data Analytics Function PCF Policy Control Function PCO Protocol Configuration Options PCRF Policy and Charging Rules Function PDB Packet Delay Budget PDR Packet Detection Rule PDU Protocol Data Unit PEI Permanent Equipment Identifier PER Packet Error Rate PFD Packet Flow Description PLMN Public Land Mobile Network PNI-NPN Public Network Integrated Non-Public Network PPD Paging Policy Differentiation PPF Paging Proceed Flag PPI Paging Policy Indicator PSA PDU Session Anchor PTP Precision Time Protocol QFI QoS Flow Identifier QoE Quality of Experience RACS Radio Capabilities Signalling optimisation (R)AN (Radio)Access Network RAT Radio Access Technology RG Residential Gateway RIM Remote Interference Management RQA Reflective QoS Attribute RQI Reflective QoS Indication RRC Radio Resource Control RSN Redundancy Sequence Number RSRP Reference Signal Received Power RSRQ Reference Signal Received Quality SA NR Standalone New Radio SBA Service Based Architecture SBI Service Based Interface SCP Service Communication Proxy SD Slice Differentiator SEAF Security Anchor Functionality SENSE Signal Level Enhanced Network Selection SEPP Security Edge Protection Proxy SIB System Information Block SINR Signal to Interference plus Noise Ratio SMF Session Management Function SMSF Short Message Service Function SN Sequence Number SN name Serving Network Name SNPN Stand-alone Non-Public Network S-NSSAI Single Network Slice Selection Assistance Information SOR Steering Of Roaming SSC Session and Service Continuity SSCMSP Session and Service Continuity Mode Selection Policy SST Slice / Service Type SUCI Subscription Concealed Identifier SUPI Subscription Permanent Identifier SV Software Version TAI Tracking Area Identity(TAI) TAU Tracking Area Update TMSI Temporary Mobile Subscriber Identity TNAN Trusted Non-3GPP Access Network TNAP Trusted Non-3GPP Access Point TNGF Trusted Non-3GPP Gateway Function TNL Transport Network Layer TNLA Transport Network Layer Association TSC Time Sensitive Communication TSCAI TSC Assistance Information TSN Time Sensitive Networking TSN GM TSN Grand Master TSP Traffic Steering Policy TT TSN Translator TWIF Trusted WLAN Interworking Function UCMF UE radio Capability Management Function UDM Unified Data Management UDR Unified Data Repository UDSF Unstructured Data Storage Function UE User Equipment UL Uplink UL CL Uplink Classifier UPF User Plane Function UPSI UE Policy Section Identifier URLLC Ultra Reliable Low Latency Communication URRP-AMF UE Reachability Request Parameter for AMF URSP UE Route Selection Policy USIM User Services Identity Module VID VLAN Identifier VLAN Virtual Local Area Network VPLMN Visited Public Land Mobile Network W-5GAN Wireline 5G Access Network W-5GBAN Wireline BBF Access Network W-5GCAN Wireline 5G Cable Access Network W-AGF Wireline Access Gateway Function

[0030] (definition) For the purposes of this document, the terms and definitions in 3GPP TR 21.905 and below apply. Where the same term exists in 3GPP TR 21.905, the definition in this document takes precedence over that term.

[0031] (General) Those skilled in the art will understand that elements in the figures are illustrated for simplicity and may not necessarily be drawn to scale. Further, with respect to the configuration of a device, one or more components of the device may be represented in the figures by conventional symbols, and the figures may show only certain details relevant to an understanding of aspects of the present disclosure so as not to obscure the figures with details that will be readily apparent to one of ordinary skill in the art having the benefit of the description herein.

[0032] For the purposes of promoting an understanding of the principles of the present disclosure, reference will be made to the embodiments illustrated in the drawings and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the present disclosure is thereby intended. Such changes and further modifications in the illustrated systems, and such further applications of the principles of the present disclosure as would normally occur to one skilled in the art, are to be construed as being within the scope of the present disclosure.

[0033] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that includes a list of steps does not include only those steps, but may also include other steps not expressly listed or inherent in such process or method. Similarly, one or more devices or entities or subsystems or elements or structures or components preceded by "comprises...a" does not, without further constraints, exclude the presence of other devices, subsystems, elements, structures, components, additional devices, additional subsystems, additional elements, additional structures, or additional components. Throughout this specification, appearances of the phrases "in an embodiment," "in another embodiment," and similar language may, but do not necessarily, all refer to the same embodiment.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The systems, methods, and examples provided herein are illustrative only and are not intended to be limiting.

[0035] In the following specification and claims, reference will be made to a number of terms that may be defined to have the following meanings: The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0036] As used herein, information relates to data and knowledge, as data is meaningful information and represents values ​​attributed to parameters. Further knowledge represents an understanding of abstract or concrete concepts. It should be noted that this exemplary system is simplified to facilitate explanation of the disclosed subject matter and is not intended to limit the scope of the present disclosure. Other devices, systems, and configurations may be used in addition to or instead of the system to implement aspects disclosed herein, and all such aspects are considered to be within the scope of the present disclosure.

[0037] Each of the aspects (e.g., the first aspect, the second aspect, the third aspect, the first example of the first aspect, the second example of the first aspect, the third example of the first aspect, the fourth example of the first aspect, the first example of the second aspect, the second example of the second aspect, the third example of the second aspect, and variations of each aspect) and elements included in each aspect described below may be implemented independently or in combination with any of the others. These aspects include novel features that differ from one another. Thus, these aspects contribute to achieving different objectives or solving different problems and to obtaining different advantages from one another.

[0038] Any list described in the following aspects includes at least one parameter or multiple parameters.

[0039] An exemplary object of the present disclosure is to provide a method and apparatus that can solve the above problems.

[0040] (First aspect) This aspect discloses a mechanism in a shared RAN environment that allows a UE registered in a failed core network to be moved to another participating PLMN that can provide disaster roaming services as defined in 3GPP TS 23.501 (Patent Document 3).

[0041] (First example of the first aspect) If a PLMN cannot provide connectivity services (e.g., voice calls, mobile data services) due to a core network failure, the shared RAN node indicates the PLMN failure to UEs registered in the PLMN and triggers disaster roaming services to another participating PLMN as defined in 3GPP TS 23.501 (Patent Document 3). This example discloses a mechanism for detecting a disaster condition in a PLMN.

[0042] Hereinafter, a detailed process of a first example of the first aspect will be described with reference to Fig. 1. Fig. 1 shows a scheme for triggering (decided by RAN) a registration procedure for disaster roaming.

[0043] Step 1. The shared RAN 5 sends an NG SETUP request message containing a list of connected PLMNs (or any other notation list of PLMNs sharing the same RAN) to the Access and Mobility Management Function (AMF) 7001. The list of connected PLMNs includes all PLMNs for which the shared RAN 5 has at least one Next Generation Application Protocol (NGAP) association with an AMF belonging to a PLMN included in the list of connected PLMNs provided by the shared RAN 5.

[0044] In one example, the shared RAN 5 includes in the list of connected PLMNs only PLMNs that have at least one NGAP association with the listed AMF, and that PLMN provides disaster roaming services through PLMN 1 to which AMF 7001 belongs.

[0045] Step 2. Upon receiving the message in step 1, the AMF 7001 sends an NG SETUP response message including a list of disaster roaming PLMNs to the shared RAN 5. The list of disaster roaming PLMNs includes all PLMNs, and the PLMN 1 may or may not have a service level agreement (SLA) for disaster roaming service. The list of disaster roaming PLMNs may include priority information among the listed PLMNs. For example, the PLMNs are listed in order of priority, with the first PLMN being the highest priority PLMN. For example, the PLMNs are listed in order of priority, with the last PLMN being the highest priority PLMN. For example, the disaster roaming PLMN is a PLMN that provides service when other PLMNs cannot provide service, or a PLMN that does not provide service when other PLMNs cannot provide service.

[0046] When multiple Tracking Areas (TAs) are configured in the shared RAN 5, the list of disaster roaming PLMNs is assigned on a tracking area basis (i.e., TAC basis or Tracking Area Code basis). For example, the list of disaster roaming PLMNs may belong to the supported TA item parameter as defined in 3GPP TS 38.413 (Patent Document 8).

[0047] 3GPP TS 23.501 (Patent Document 3) defines disaster roaming services as follows: Disaster roaming services are limited to the geographic area affected by the disaster condition. The NG-RAN nodes and AMFs in the PLMN providing disaster roaming services are configured with area information, i.e., with a list of TAIs that may be established by the PLMN providing disaster roaming services based on the geographic area of ​​the disaster condition in other PLMN(s).

[0048] When multiple AMFs are deployed and connected to the shared RAN 5, the list of disaster roaming PLMNs from the AMF 7001 may be valid for all AMFs in PLMN 1. That is, one AMF may represent PLMN 1 and configure the list of disaster roaming PLMNs in the shared RAN 1.

[0049] Step 3. PLMN1 experiences a network failure situation. Although step 3 indicates that AMF 7001 has failed, this does not mean that only AMF 7001 in PLMN1 has failed. Step 3 may indicate that a partial or complete 5G Core Network (5GC) node has failed, or that the underlying network of 5GC in PLMN1 has failed, and that connectivity services (e.g., voice calls, mobile data services) cannot be provided by PLMN1. For example, this failure may be detected by an Operation and Maintenance (OAM) system or any other monitoring function in PLMN1.

[0050] Step 4. Shared RAN 5 detects that any connectivity services (e.g., voice calls, mobile data services) cannot be provided by PLMN 1 and decides to trigger disaster roaming services by other participating PLMNs (i.e., PLMNs that share the same RAN node as PLMN 1). This detection may be one or a combination of the following: The shared RAN 5 receives an OAM message from the OAM system, any other monitoring function within the PLMN 1, or other network element (e.g., AMF) within the PLMN 1 indicating that the PLMN 1 is experiencing a network failure and that disaster roaming services are required. In one example, the shared RAN 5 receives a message from the OAM system, any other monitoring function within the PLMN, or other network element (e.g., AMF) within the PLMN 1 indicating that a network failure or disaster roaming services are required. All NGAP connections (i.e., N2 reference points) that were connected from the shared RAN to the AMF of PLMN1 are lost. For example, the loss of an NGAP connection can be detected by a failure in the lower layers of the NGAP protocol or by an NGAP adaptive heartbeat time interval timeout.

[0051] Step 5. When the shared RAN 5 decides to trigger disaster roaming services with another participating PLMN, both steps 5a and 5b are performed. Step 5a is referenced by UEs registered with PLMN1 that are in RRC Idle state, while step 5b is a dedicated indication to UEs that are in RRC Connected state with PLMN1. That is, step 5b is performed for all UEs registered with PLMN1 that are in RRC Connected state.

[0052] Step 5a. The shared RAN 5 broadcasts a new System Information Block (SIB) including a disaster status indication, a failed PLMN, and a list of disaster roaming PLMNs (PLMN2, PLMN3 with priority). In one example, the new SIB is broadcast or transmitted via a Broadcast Control Channel (BCCH). In one example, the shared RAN 5 can broadcast or transmit a new SIB including at least one of the disaster status indication, information related to the failed PLMN, and information related to the PLMN providing roaming when another PLMN experiences a network failure situation. In one example, the failed PLMN can be information about PLMN1 or information about the PLMN experiencing the network failure situation. In one example, the disaster status indication parameter can indicate that PLMN1 is experiencing a disaster situation and is unable to provide connectivity service, thus requiring disaster roaming service. In one example, the disaster status indication indicates the damage area, the damage time, the damage duration, the damage cause, the damage time, etc.

[0053] The combination of the disaster state indication and the failed PLMN indicates that the PLMN in the failed PLMN is in a disaster state and all UEs registered in the failed PLMN must perform the registration procedure for disaster roaming service. In one example, the failed PLMN alone indicates that the PLMN is in a disaster state and all UEs registered in the failed PLMN must perform the registration procedure for disaster roaming service.

[0054] The disaster roaming PLMN list indicates PLMNs that can provide disaster roaming service. The disaster roaming PLMN list can indicate PLMNs that provide roaming service when other PLMNs encounter a network failure situation. The disaster roaming PLMN list may also include priority information among the listed PLMNs. For example, the PLMNs are listed in order from highest priority to lowest priority, with the first PLMN being the highest priority PLMN. For example, the PLMNs are listed in order from lowest priority to highest priority, with the last PLMN being the highest priority PLMN.

[0055] If multiple tracking areas are configured in the shared RAN5, the cells connected to the shared RAN5 broadcast a list of disaster roaming PLMNs in the new SIB that correspond to the TACs of the cells in the list of disaster roaming PLMNs received in step 2.

[0056] Step 5b. The shared RAN 5 sends an RRC release message to the UEs having an RRC connection with any AMF belonging to the PLMN (PLMN1 in this example) that is under the disaster condition.

[0057] The RRC release message contains a disaster status indication, the PLMN in which the failure occurred, and a list of disaster roaming PLMNs (PLMN2, PLMN3 with priority). For details of the parameters, see step 5a in this example.

[0058] The RRC release message may also include redirectedCarrierInfo indicating the current cell that belongs to the shared RAN 5. This indicates to the UE 3 not to reselect another cell because the current cell with the shared RAN 5 can provide disaster roaming service to the UE 3.

[0059] Step 6. Once UE3 receives the message in either step 5a or step 5b, UE3 stays in the same cell and sends a registration request message to the AMF in the disaster roaming PLMN with the registration type set to new parameters "disaster roaming initial registration" or "disaster roaming mobility registration update" or any other notation intended to initiate disaster roaming service.

[0060] For detailed procedures of step 6, please refer to other examples of the first embodiment.

[0061] In one example, a radio station corresponding to shared RAN 5 transmits a setup request message corresponding to an NG_SETUP Request including information about a list of connected networks to a first core network node corresponding to AMF 7001 in a first network corresponding to PLMN 1. The radio station receives a setup response message corresponding to an NG_SETUP response from the first core network node including at least one of information about the list of roaming networks (e.g., information related to PLMN 2 or PLMN 3) and information about the priority of the roaming networks (e.g., disaster roaming priority). The radio station detects a failure of a connection between the first core network node or another core network node in the first network. The radio station receives information related to a disaster state of the first network corresponding to a disaster state indication, information about the first network (i.e., the location where the failure occurred), and information about the first network (i.e., the location where the failure occurred). and transmitting at least one of the following to the radio terminal corresponding to the UE: information related to the disaster state of the first network (disaster state indication), information about the first network (failed PLMN=1), the list of roaming networks (e.g., PLMN2, PLMN3), and information about the priority of the roaming networks (e.g., disaster roaming priority). The information related to the disaster state of the first network (disaster state indication), information about the first network (failed PLMN=1), the list of roaming networks (e.g., PLMN2, PLMN3), and information about the priority of the roaming networks (e.g., disaster roaming priority) may be included in the System Information Block (SIB) message in step 5a or the Radio Resource Control Release message in step 5b.

[0062] In one example, a first core network node corresponds to AMF 7001 in a first network corresponding to PLMN 1 and receives a setup request message corresponding to an NG_SETUP Request including information about a list of connected networks from a radio station corresponding to shared RAN 5. The first core network node transmits a setup response message corresponding to an NG_SETUP response to the radio station including at least one of information about a list of disaster roaming networks (e.g., PLMN 2, PLMN 3) and information about the priority of the disaster roaming networks (e.g., disaster roaming priority).

[0063] In one example, a radio terminal corresponding to the UE receives at least one of information related to a disaster state of a first network corresponding to the disaster state indication, information about the first network corresponding to information related to PLMN1 in which the failure occurred, information about a list of roaming networks (e.g., PLMN2, PLMN3), and information about a priority of roaming networks (e.g., disaster roaming priority) from a radio station corresponding to the shared RAN 5. The radio terminal transmits a registration request message having parameters used for initiating disaster roaming service (e.g., at least one type of information related to disaster roaming initial registration, disaster roaming mobility registration update, and an indication of new parameters for initiating disaster roaming service) to a second core network node corresponding to AMF 7002 or AMF 7003 in the roaming network (e.g., PLMN2, PLMN3).

[0064] (Modification 1 of the first example of the first aspect) In step 1, the message sent from the shared RAN 5 to the AMF 7001 may be a RAN CONFIGURATION UPDATE message having the parameters as described in step 1. In step 2, the message returned from the AMF 7001 may be a RAN CONFIGURATION UPDATE ACKNOWLEDGE message having the parameters as described in step 2.

[0065] (Modification 2 of the first example of the first aspect) The list of disaster roaming PLMN parameters described in step 2 may be conveyed by an AMF CONFIGURATION UPDATE message sent by the AMF 7001 to the shared RAN 5. The list of connected PLMN parameters described in step 1 may be conveyed by an AMF CONFIGURATION UPDATE ACKNOWLEDGE message.

[0066] (Modification 3 of the first example of the first aspect) In step 5b, the RRC release message may be an RRC reconfiguration message, or any other new or existing RRC message.

[0067] (Modification 4 of the first example of the first aspect) In step 5a, the shared RAN 5 gradually broadcasts the new SIBs per Tracking Area Identity (TAI) or per cell to avoid an overload situation due to a large number of disaster roaming service requests.

[0068] Similarly, in step 5b, the shared RAN 5 gradually sends RRC release messages to the users of the UEs, UE by UE, to avoid an overload situation due to a large number of disaster roaming service requests.

[0069] (Modification 5 of the first example of the first aspect) In one example, in step 6, the UE 3 is capable of roaming during a disaster, and only if the UE 3 fails to register with a PLMN during a disaster, the UE 3 triggers registration with a PLMN that supports roaming during a disaster.

[0070] (Modification 6 of the first example of the first aspect) In another example, in step 6, the UE 3 may not know which RAN 5 sharing the PLMN provides disaster roaming service; for example, the roaming capability of the disaster network is not broadcast in the SIB message in step 5a or via the RRC release message in step 5b. In this case, roaming in the disaster-ready UE 3 may include, in the RRC message to the RAN 5 during registration in step 6, an indication of a new parameter, for example, a "disaster roaming" parameter, or any other parameter to indicate to the RAN 5 that the UE 3 is requesting a connection for disaster roaming. This new parameter "disaster roaming" may be included in one of the existing Access Stratum (AS) messages, such as the RRC Configuration Establishment Request or RRC Connection Establishment Complete message, or in a new AS message. If the UE indicates the "disaster roaming" parameter in the AS message, the RAN 5 selects a shared AMF from a PLMN that supports roaming during disaster registration and service.

[0071] (Modification 7 of the first example of the first aspect) In step 4, if UE3 is in RRC-Connected Inactive state, when shared RAN5 determines that PLMN1 has failed, shared RAN5 moves to state RRC-IDLE. In step 5, if UE3 is in RRC-Connected Inactive mode, UE3 moves to RRC-IDLE mode and performs step 6.

[0072] (Modification 8 of the first example of the first aspect) In one example, if UE3 is in an RRC-Connected state and shared RAN5 determines in step 5 to direct UE3 to the highest priority PLMN (e.g., PLMN2) from the disaster roaming PLMN list, shared RAN5 allocates radio resources to UE3 and sends an RRC reconfiguration message to UE3 including the radio resources (single radio bearer or dedicated radio bearer) of PLMN2. In addition, shared RAN5 includes at least one of the parameters sent in step 5a or 5b and PLMN ID 2. When UE3 receives the RRC reconfiguration message with disaster roaming indication and PLMN2 id 2, UE3 initiates the registration procedure to PLMN2 over the existing RRC connection.

[0073] (Modification 8 of the first example of the first aspect) In one example, UE3 is in an RRC-idle state, shared RAN5 receives an RRC connection request message, and shared RAN5 determines to direct UE3 to the highest priority PLMN (e.g., PLMN2) from the disaster roaming PLMN list. Shared RAN5 allocates radio resources to UE3 and sends an RRC setup message to UE3 including the radio resources (single radio bearer or dedicated radio bearer) of PLMN2. In addition, shared RAN5 includes at least one of the parameters sent in step 5a or 5b and PLMN ID 2.

[0074] When UE3 receives the RRC reconfiguration message with disaster roaming indication and PLMN2 id 2, UE3 initiates the registration procedure to PLMN2 over the existing RRC connection.

[0075] (Modification 9 of the first example of the first aspect) In step 2, PLMN1 indicates a disaster condition indication to the shared RAN 5 so that UE3 initiates roaming to another PLMN (e.g., PLMN2) to resume connectivity services under a disaster roaming scenario. An SLA-based Multi Operator Core Network (MOCN) sharing scenario may be considered to save costs. In the MOCN sharing scenario, PLMN1 also indicates a disaster condition indication to other MOCN PLMNs (e.g., PLMN2 and PLMN3) using Internet Protocol security (IPsec), as described in 3GPP TS 33.210 (Patent Document 12), thereby preparing the other MOCN PLMNs to provide service to UE3 of PLMN1 under a disaster roaming scenario.

[0076] (Second example of the first aspect) If a PLMN cannot provide connectivity services (e.g., voice calls, mobile data services) due to a core network failure, the shared RAN node indicates the PLMN failure to users of UEs registered in the PLMN and triggers disaster roaming services to another participating PLMN as defined in 3GPP TS 23.501 (Patent Document 3). This example discloses a mechanism for detecting a disaster state in a PLMN.

[0077] Hereinafter, a detailed process of the second example of the first aspect will be described with reference to Figure 2. Figure 2 shows a scheme for triggering a registration procedure (determined by 5GC) for disaster roaming.

[0078] Step 0. Steps 1 and 2 in the first example of the first embodiment are performed.

[0079] Step 1. PLMN1 experiences a network failure and decides to activate a disaster roaming service. In one example, a node within PLMN1 decides to activate a disaster roaming service. The node may be any of the core network nodes.

[0080] Step 2. Upon determining in step 1 that disaster roaming service activation is required, an entity within PLMN1 sends a message to AMF 7001 indicating that Minimization of service interruption (MINT) service (e.g., disaster roaming service) is required. The entity may be any 5GC node or OAM system within PLMN1. This message may include parameters indicating the available services that PLMN1 can still provide. For example, all connectivity services except emergency call services are unavailable.

[0081] Step 3. If the AMF 7001 is still able to communicate with the shared RAN 5 and the message in step 2 indicates a disaster condition indication, the AMF 7001 proceeds with step 4 and subsequent steps for all connected RANs.

[0082] Step 4. The AMF 7001 sends an AMF Status Indication message to the shared RAN 5, including a new cause, a disaster status indication, and available services. The new cause parameter may indicate that this message is related to disaster roaming services. The disaster status indication parameter may indicate that PLMN1 is experiencing a disaster condition and is unable to provide connectivity services, therefore disaster roaming services are required. The available services may be parameters copied from the available services parameters of step 2. This information related to available services may include parameters indicating the available services that PLMN1 can still provide. For example, all connectivity services except emergency call services are unavailable.

[0083] Step 5. Steps 5 and 6 from the first example of the first embodiment are performed. Furthermore, the messages of steps 5a and 5b in the first example of the first aspect may include available service parameters. The available service parameters may be referenced by UE 3 to use the services indicated in the available service parameters, regardless of whether UE 3 is stationed in PLMN 1. For example, if the available service parameters indicate an emergency service, UE 3 can use the emergency service in PLMN 1. When UE 3 initiates the emergency service, shared RAN 5 accepts an RRC establishment message from UE 3 only if the RRC_establishment cause is emergency.

[0084] In one example, a first core network node receives a setup request message corresponding to an NG_SETUP Request from a radio station corresponding to a shared RAN 5, the setup request message corresponding to an AMF 7001 in a first network corresponding to a PLMN 5, and the setup request message includes information about a list of connected networks. The first core network node transmits a setup response message corresponding to an NG_SETUP response to the radio station, the setup response message including at least one of information about a list of disaster roaming networks (e.g., PLMN2, PLMN3) and information about the priority of the disaster roaming networks (e.g., disaster roaming priority). The first core network node receives information indicating that service interruption minimization is required (e.g., a MINT required signal) from a second core network node in the first network or any network node in PLMN1. The first core network node transmits information including at least one of a new cause parameter, a disaster status indication parameter, and an available service parameter to the radio station.

[0085] (Modification 1 of the second example of the first aspect) In step 4, the AMF7001 status indication message may be another NGAP message, for example, an AMF CONFIGURATION UPDATE message, an NG RESET message, an ERROR INDICATION message, an OVERLOAD START message, or an existing or new NGAP message.

[0086] (Third example of the first aspect) If UE3 is in RRC_Idle state and UE3 knows that PLMN1 is experiencing a network failure, UE3 may then decide to perform disaster roaming service to another participating PLMN.

[0087] Hereinafter, a detailed process of the third example of the first aspect will be described with reference to Figure 3. Figure 3 shows a scheme for initiating disaster roaming service when the UE is in RRC Idle state.

[0088] Step 0. When UE3 is in RRC_Idle state and UE3 recognizes that PLMN1 experiences a network failure, UE3 can then decide to perform disaster roaming service to another participating PLMN. In one example, as described in step 5a of the first example of the first aspect, UE3 determines to perform disaster roaming service when UE3 receives SIB information. In another example, as described in step 5b of the first example of the first aspect, UE3 determines to perform disaster roaming service when UE3 receives an RRC release message.

[0089] Step 1. UE3 sends an RRC Setup Request message to the shared RAN5, including an establishment cause, a UE identity, and a disaster roaming capability indication. The UE identity indicates the identity of the UE3. The UE identity may take the form of a 5G-S-TMSI. The disaster roaming capability indication indicates that the UE3 has the capability to support the disaster roaming service. In one example, the disaster roaming capability indication indicates that the UE3 has the capability to support the disaster roaming service at the AS layer, i.e., between the UE3 and the shared RAN5.

[0090] In another example, the disaster roaming capability indication indicates that the UE 3 has the capability to support disaster roaming services at both the AS layer and the Non-Access-Stratum (NAS) layer, i.e., between the UE 3 and the shared RAN 5 and between the UE 3 and the AMF.

[0091] Step 2. Upon receiving the RRC Setup Request message in step 1, the shared RAN 5 sends an RRC Setup Request message to the UE 3, including a disaster status indication, the PLMN in which the failure occurred, and a list of disaster roaming PLMNs (PLMN2 in this example). For details of the parameters, see step 5a of the first example of the first aspect.

[0092] Step 3. UE3 sends an RRC Setup Complete message containing SelectedPLMN-Identity=PLMN1, Disaster Roaming Capability Indicator, Disaster State Indicator, Redirection Indicator, and a NAS container. Because the UE is registered with PLMN1 and has been assigned a 5G-S-TMSI or UE identity by PLMN1, the Selected PLMN-ID indicates PLMN1. For details about the Disaster Roaming Capability Indicator, see step 1 for details. Disaster Roaming Capability does not need to be reconfigured by UE3 if this indication is set in the RRC Setup Request message in step 1. The Disaster State Indicator indicates that the associated PLMN indicated by the Selected PLMN-ID (PLMN1 in this example) is experiencing a disaster condition and is unable to provide connectivity services (e.g., voice calls, mobile data services). The Redirection Indicator includes the PLMN to which UE3 requests to be redirected for disaster roaming services (PLMN2 in this example).

[0093] The NAS container includes a registration request message. The registration request message includes a disaster roaming capability indication and / or a disaster state indication. The disaster roaming capability indication indicates to the AMF that the UE3 has the capability to support disaster roaming services at the NAS layer, i.e., between the UE3 and the AMF. The disaster state indication indicates that the associated PLMN (PLMN1 in this example) is experiencing a disaster state and may not be able to provide connectivity services (e.g., voice calls, mobile data services).

[0094] If the UE 3 does not perform disaster roaming services, the UE 3 may perform other actions, such as PLMN selection.

[0095] Step 4. When the shared RAN 5 determines to provide disaster roaming service by the PLMN 2, the shared RAN 5 sends a UE initial message including a registration request message to the AMF 7002 in the PLMN 2. The registration request message includes a disaster roaming capability indication and a disaster state indication. In one example, for the disaster roaming capability indication, see step 3 for details of the disaster roaming capability indication. In one example, for the disaster state indication, see steps 2 and 3 for details of the disaster state indication.

[0096] The shared RAN 5 may decide to provide disaster roaming service via the PLMN 2 if at least one of the following conditions is met: In the RRC Setup Complete message, the UE 3 indicates the Disaster Roaming Capability Indication=Supported, the Disaster Condition Indication and the Redirect indication=PLMN2. In the RRC Setup Complete message, UE3 indicates the Disaster Roaming Capability Indication=Supported, Disaster Condition Indication, and the Selected PLMN-Identity=PLMN1. The shared RAN5 then decides to redirect UE3 to PLMN2 based on internal data within the shared RAN5. For example, the internal data within the shared RAN5 may be constructed according to step 4 of the first example of the first aspect, where PLMN2 is listed as the highest priority among the candidate PLMNs. As another example, the internal data within the shared RAN5 may be constructed when the shared RAN5 receives the message, as described in step 4 of the second example of the first aspect, where PLMN2 is listed as the highest priority among the candidate PLMNs.

[0097] Step 5. When the AMF 7002 receives the registration request message from the UE 3 via the RAN, authentication and security procedures are performed taking into account disaster roaming services, as described in section 4.2.2.2.2 of 3GPP TS 23.502 (Patent Document 4).

[0098] Step 6. The AMF 7002 sends a Nudm_UECM_Registration request message to the Unified Data Management (UDM) 75 in PLMN1, including the disaster roaming capability indication and disaster status indication received in the registration request message in step 4. For example, if the UE3 is an arriving roamer in PLMN1, the UDM 75 may not belong to PLMN1.

[0099] Step 7. Upon receiving the Nudm_UECM_Registration request message in step 6, UDM 75 sends a Nudm_UECM_Registration response message to AMF 7002. Because the disaster status indication is indicated in the Nudm_UECM_Registration request message, UDM 75 registers AMF 7002 as a roaming node even though a roaming agreement with PLMN 2 has not been concluded.

[0100] Step 8. The AMF 7002 sends a Nudm_SDM_Get request message to the UDM 75 of PLMN 1, including the disaster roaming capability indication and disaster status indication received in the registration request message in step 4.

[0101] Step 9. Upon receiving the Nudm_SDM_Get request message in step 8, the UDM 75 sends a Nudm_UECM_Registration response message including disaster subscriber data to the AMF 7002. Because a disaster status indication is indicated in the Nudm_SDM_Get request message, the UDM 75 provides the dedicated subscriber data to the AMF 7002 even though a roaming agreement with the PLMN 2 has not been concluded.

[0102] The UDM 75 is able to provide the full set of subscriber data to the AMF 7002 even if a roaming agreement with the PLMN 2 is not established, because the disaster condition indication is indicated in the Nudm_SDM_Get request message based on the operator configuration or / and roaming agreement.

[0103] Step 10. The registration procedure continues with step 14c of section 4.2.2.2.2 of 3GPP TS 23.502 (Patent Document 4).

[0104] In one example, a wireless terminal corresponding to a UE (User Equipment User Equipment) determines to perform disaster-related roaming services. The wireless terminal transmits a Radio Resource Control (RRC) Setup Request message to a wireless station corresponding to a shared RAN 5, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services corresponding to a disaster roaming capability indication. The wireless terminal receives from the wireless station at least one of information related to the disaster state of the first network corresponding to the disaster state indication, information about the first network corresponding to information related to PLMN1 in which the disaster-related failure occurred, information about a list of roaming networks (e.g., PLMN2, PLMN3), and information about roaming network priorities (e.g., disaster roaming priority). The wireless terminal transmits an RRC Setup Complete message to the wireless station, the message including at least one of information about the first network (e.g., selected PLMN-ID PLMN1), information indicating that the wireless terminal has the capability to support disaster-related roaming services corresponding to the disaster roaming capability indication, and information related to the disaster state of the first network corresponding to the disaster information indication. The wireless terminal transmits information related to the roaming network (e.g., a redirection indication related to PLMN2) to the wireless station. The wireless terminal transmits Non-Access Stratum (NAS) container information (e.g., a NAS container) to the wireless station, the NAS container including registration request information including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services corresponding to the disaster roaming capability indication, and information related to a disaster state of the first network corresponding to the disaster state indication.

[0105] In one example, a radio station corresponding to the shared RAN 5 receives a Radio Resource Control (RRC) Setup Request message from a radio terminal corresponding to a UE, the message including information indicating that the radio terminal has the capability to support disaster-related roaming services corresponding to the disaster roaming capability indication. The radio station transmits at least one of information related to the disaster state of the first network corresponding to the disaster state indication, information about the disaster-related first network (e.g., information related to PLMN1 where the failure occurred), information about a list of roaming networks (e.g., PLMN2, PLMN3), and information about roaming network priorities (e.g., disaster roaming priorities) to the radio terminal. The radio station receives an RRC Setup Complete message from the radio terminal, the message including at least one of information about the first network (e.g., information about a selected PLMN-ID associated with PLMN1), information indicating that the radio terminal has the capability to support disaster-related roaming services corresponding to the disaster roaming capability indication, and information related to the disaster state of the first network corresponding to the disaster state indication. The radio station receives information related to the roaming network (e.g., Redirection Indicator (PLMN2)) from the radio terminal. The radio station receives Non-Access Stratum (NAS) container information (e.g., a NAS container) from the radio terminal, the NAS container information including registration request information including at least one of information indicating that the radio terminal has a capability to support disaster-related roaming services corresponding to the disaster roaming capability indication and information related to a disaster state of the first network corresponding to the disaster state indication. The radio station transmits a registration request message including at least one of information indicating that the radio terminal has a capability to support disaster-related roaming services corresponding to the disaster roaming capability indication and information related to a disaster state of the first network corresponding to the disaster state indication to a third core network node corresponding to AMF7002 in a roaming network corresponding to PLMN2.

[0106] In one example, a fourth core network node corresponding to UDM 75 in the first network corresponding to PLMN 1 associated with the disaster may: and receiving a message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services corresponding to the disaster roaming capability indication (disaster roaming capability indication) and information related to a disaster state of the first network corresponding to the disaster state indication (disaster state indication) from a third core network node corresponding to AMF7002 in a roaming network corresponding to PLMN2. The fourth core network node receives a message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services corresponding to the disaster roaming capability indication (disaster roaming capability indication) and information related to a disaster state of the first network corresponding to the disaster state indication (disaster state indication) from the third core network node. The fourth core network node transmits the message including the subscriber data to the third core network node.

[0107] In one example, a third core network node corresponding to AMF 7002 in a second network corresponding to PLMN2 receives a registration request message from a radio station corresponding to shared RAN 5, the registration request message including at least one of information indicating that the radio terminal has the capability to support disaster-related roaming services corresponding to the disaster roaming capability indication and information related to the disaster state of the first network corresponding to the disaster state indication. The third core network node transmits the message including at least one of information indicating that the radio terminal has the capability to support disaster-related roaming services corresponding to the disaster roaming capability indication and information related to the disaster state of the first network corresponding to the disaster state indication to a fourth core network node corresponding to UDM 75 in the disaster-related first network, PLMN1. The third core network node transmits the message including at least one of information indicating that the radio terminal has the capability to support disaster-related roaming services (e.g., disaster roaming capability indication) and information related to the disaster state of the first network (e.g., disaster state indication) to the fourth core network node corresponding to UDM 75 in the disaster-related first network, PLMN1. The third core network node receives a message containing subscriber data from the fourth core network node (UDM 75 of PLMN1).

[0108] (Modification 1 of the third example of the first aspect) In step 1, the RRC setup request message may be an RRC reconfiguration request message, or any other new RRC message, or an existing RRC message.

[0109] Similarly, in step 2, the RRC setup message may be an RRC reconfiguration message or any other new or existing RRC message.

[0110] Similarly, in step 3, the RRC setup complete message may be an RRC reconfiguration complete message or any other new or existing RRC message.

[0111] (Modification 2 of the third example of the first aspect) In step 4, the shared RAN 5 may send a UE initial message to an AMF in another PLMN if all AMFs in PLMN 2, which has the highest priority among the candidate PLMNs, are in an overload state.

[0112] (Modification 3 of the third example of the first aspect) Step 0 shows an example of how UE 3 in idle mode, registered with PLMN 1, learns that PLMN 1 is in a disaster state via a system information broadcast. UE 3 in idle mode periodically reads SI messages broadcast by shared RAN 5. If the UE is registered with PLMN 1 and PLMN 1 has entered a disaster state, this can be indicated to shared RAN 5 by AMF 7001 as in step 4 of FIG. 2. Shared RAN 5 can then broadcast the disaster state of PLMN 1 in one of the SI messages with a new parameter called "PLMN in disaster," or any other notation indicating the PLMN in disaster. UE 3 can then follow steps 1 through 10 of FIG. 3 to register with another shared PLMN that provides disaster roaming services.

[0113] (Fourth Example of the First Aspect) When UE3 is in RRC_Connected state and UE3 realizes that PLMN1 experiences a network failure, UE3 may decide to perform disaster roaming service to another participating PLMN.

[0114] Hereinafter, a detailed process of the fourth example of the first aspect will be described with reference to Fig. 4. Fig. 4 shows a scheme for initiating a disaster roaming service when a UE is in an RRC connected state. This call flow can be called an extension of the RRC re-establishment procedure, fallback to RRC establishment procedure, described in Section 5.3.7.1 of 3GPP TS 38.331 (Patent Document 9).

[0115] Step 0. When UE3 is in RRC_Connected state and UE3 recognizes that PLMN1 experiences a network failure, UE3 may decide to perform disaster roaming service to another participating PLMN. In one example, as described in step 5a of the first example of the first aspect, when UE3 receives SIB information, UE3 decides to perform disaster roaming service.

[0116] In another example, as described in step 5b in the first example of the first aspect, when the UE 3 receives the RRC release message, the UE 3 decides to perform disaster roaming service.

[0117] Step 1. The UE 3 sends an RRC reconfiguration message to the shared RAN 5, including a disaster roaming capability indication, a disaster state indication, and a redirection indication.

[0118] For details of the parameters, see step 3 of the third example of the first embodiment.

[0119] Step 2: Steps 2 to 10 in the third example of the first aspect are carried out.

[0120] In one example, the wireless terminal corresponds to a UE that determines to perform disaster-related roaming services. The wireless terminal transmits a Radio Resource Control (RRC) re-establishment request message to a wireless station corresponding to the shared RAN 5, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services corresponding to the disaster roaming capability indication. The wireless terminal receives from the wireless station at least one of information related to a disaster state of the first network corresponding to the disaster state indication, information about the first network (e.g., information related to PLMN1 where the disaster-related failure occurred, information about a list of roaming networks (e.g., PLMN2, PLMN3), and information about roaming network priorities (e.g., and disaster roaming priorities). The wireless terminal transmits the information about the first network (e.g., information related to a selected PLMN-ID associated with PLMN1), the information indicating that the wireless terminal has the capability to support disaster-related roaming services. The wireless terminal transmits an RRC setup complete message to the wireless station, the RRC setup complete message including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services (e.g., disaster roaming capability indication) and information related to the disaster state of the first network (e.g., disaster state indication). The wireless terminal transmits information related to the roaming network to the wireless station corresponding to the redirection indication related to PLMN2. The wireless terminal transmits Non-Access Stratum (NAS) container information (e.g., NAS container) to the wireless station, the NAS container including registration request information including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services (e.g., disaster roaming capability indication) and information related to the disaster state of the first network (e.g., disaster state indication).

[0121] In one example, a radio station corresponding to shared RAN 5 receives a Radio Resource Control (RRC) re-establishment request message from a radio terminal corresponding to a UE, the message including information indicating that the radio terminal has the capability to support disaster-related roaming services corresponding to a disaster roaming capability indication. The radio station transmits at least one of information related to a disaster state of a first network corresponding to the disaster state indication, information about the disaster-related first network (e.g., information related to PLMN1 where the failure occurred), information about a list of roaming networks (e.g., PLMN2, PLMN3), and information about a priority of the roaming networks (e.g., disaster roaming priority) to the radio terminal. The radio station receives an RRC setup complete message from the radio terminal, the message including at least one of information about the first network (e.g., information related to PLMN1 where the failure occurred), information indicating that the radio terminal has the capability to support disaster-related roaming services (e.g., disaster roaming capability indication), and information related to the disaster state of the first network (e.g., disaster state indication). The radio station receives information related to a roaming network corresponding to a redirection indication associated with PLMN2 from the radio terminal. The radio station receives Non-Access Stratum (NAS) container information (e.g., an NAS container) from the radio terminal, the NAS container information including registration request information including at least one of information indicating that the radio terminal has the capability to support disaster-related roaming services (e.g., a disaster roaming capability indication) and information related to a disaster state of the first network (e.g., a disaster state indication). The radio station transmits a registration request message including at least one of information indicating that the radio terminal has the capability to support disaster-related roaming services (e.g., a disaster roaming capability indication) and information related to the disaster state of the first network (e.g., a disaster state indication) to a third core network node corresponding to AMF7002 in a roaming network corresponding to PLMN2.

[0122] (Second aspect) This aspect discloses a mechanism for allowing 5G-only domestic roaming users to access connectivity services (e.g., voice calls, mobile data services) provided by 4G (EPS system) in a VPLMN when a disaster situation is encountered in a 5G network.

[0123] (First example of the second aspect) PLMN1 provides 5G services to 5G-only UEs. A 5G-only UE is a UE that is granted 5G-only national roaming access to a PLMN. For example, some countries restrict national roaming between Evolved Packet Systems (EPS) because 5G coverage is not fully achieved while all PLMN operators cover the entire country. Therefore, some countries may allow national roaming with 5G.

[0124] In the event of a disaster situation due to a failure in the 5G System (5GS), 5G-only UEs via 5GS are permitted to provide disaster roaming services via EPS access only if the 5G-only UEs have lost some connection services (e.g., voice calls, mobile data services) on 5GS.

[0125] Next, a detailed process of a first example of the second aspect will be described with reference to Figure 5. Figure 5 shows a scheme of disaster roaming service to EPS for 5G-only UE.

[0126] Steps 0-1. In the PLMN 1, some or all of the subscriber data is synchronized between the Home Subscriber Server (HSS) and the Unified Data Management (UDM) 75. As an example, the HSS and the UDM 75 are synchronized using the NU1 reference point as defined in 3GPP TS 23.632 (Patent Document 11).

[0127] Steps 0-2. PLMN1 provides 5G services to the 5G-only UE. The 5G-only UE may be restricted from accessing the EPS due to, for example, 1) the access restriction data being set as not allowing access to the EPS in the UDM / HSS subscription data, or 2) the roaming to the EPS portion of the VPLMN being not allowed in the UDM / HSS subscription data, or 3) the UE not having valid EPS subscription data in the HSS.

[0128] Step 1. UE3 recognizes that PLMN1 is experiencing a network failure. UE3 can then decide to perform disaster roaming service to another PLMN, including an EPS network. In one example, UE3 decides to perform disaster roaming service to the EPS network when UE3 receives SIB information, as described in step 5a of the first example of the first aspect. The list of disaster roaming PLMNs in step 5a of the first example of the first aspect may have an indication of EPS support for each listed PLMN.

[0129] In another example, the UE 3 determines to perform disaster roaming service to the EPS network when the UE 3 receives the RRC release message as described in step 5b of the first example of the first aspect. In step 5b of the first example of the first aspect, the list of disaster roaming PLMNs may have an indication of EPS support for each listed PLMN.

[0130] Step 2. UE3 sends an attach request message to a Mobility Management Entity (MME) in PLMN2 via an eNodeB in PLMN2 containing a disaster roaming capability indication. For parameter details, see step 3 of the third example of the first aspect. In one example, the attach request message may be a Tracking Area Update (TAU) request message.

[0131] Step 3. When the MME receives the attach request message from the UE 3, authentication and security procedures may take place.

[0132] Step 4. The MME sends a location update request message to the HSS in PLMN1, including the International Mobile Subscriber Identity (IMSI) and disaster roaming capability indication received in the attach request message or TAU request message in step 2.

[0133] Step 5. Upon receiving the Location Update Request message in step 4, the HSS sends a Location Response message containing the subscriber data for disaster roaming to the MME. If the following conditions are met, the HSS provides the dedicated subscriber data to the MME: - While no roaming agreement is established with PLMN2, a disaster status indication is shown in the location update request message. - As long as PLMN2 is registered as "no roaming" in the subscriber data of UE3, a disaster status indication is shown in the location update request message. -Even if there is subscription data for 5GS access but no subscriber data for EPS access, the disaster status indication is indicated in the location information update request message. In this case, the HSS generates disaster subscriber data for EPS based on the subscriber data for 5GS.

[0134] Step 6. When the MME receives the Location Information Response message, it continues with the attach procedure at step 12 of section 5.3.2.1 of 3GPP TS 23.401 (Patent Document 10).

[0135] If the message in step 2 is a TAU request message, the MME continues the tracking area update procedure in step 8 of section 5.3.3.1 of 3GPP TS 23.401 (Patent Document 10).

[0136] If the access restriction data of the disaster subscriber data received from the HSS in step 5 is set to "E-UTRAN not allowed", the MME shall ignore this data and continue the attach procedure or tracking area update procedure exceptionally as a disaster roaming service.

[0137] In one example, a wireless terminal corresponding to a UE in a 5G network determines to perform a disaster-related roaming service, and transmits information indicating that the wireless terminal has a capability to support the disaster-related roaming service, corresponding to the disaster roaming capability indication, to a fifth core network node corresponding to an MME in a PLMN2 in a 4G network.

[0138] In one example, a sixth core network node corresponding to an HSS of PLMN1 in a 5G network receives information indicating that the wireless terminal has the capability to support disaster-related roaming services corresponding to the disaster roaming capability indication from a fifth core network node corresponding to an MME of PLMN2 in a 4G network, and transmits subscriber data to the fifth core network node.

[0139] (Modification 1 of the first example of the second aspect) Once the disaster condition is confirmed and 5G service via PLMN1 becomes available, this recovery information shall be provided to the HSS. The HSS then initiates an HSS-initiated detach procedure as described in section 5.3.8.4 of 3GPP TS 23.401. In this case, the location information cancel message from the HSS to the MME may include a "return to 5G" parameter indicating that disaster roaming service can no longer be validated via the 5G-only UE's EPS. When the MME receives the "return to 5G" parameter in the location information cancel message, the MME may send a detach request message to the UE 3 including a "return to 5G" parameter indicating to the UE 3 that 5GS service is available and the UE 3 can return to 5GS.

[0140] (Modification 2 of the first example of the second aspect) When the disaster condition is resolved and 5G service via PLMN1 becomes available, this restoration information shall be provided to the MME. The MME then initiates an MME-initiated detach procedure as described in section 5.3.8.3 of 3GPP TS 23.401. In this case, the MME sends a DETACH REQUEST message to the UE 3, including a "Return to 5G" parameter, indicating to the UE 3 that 5GS service is available and that it may return to 5GS.

[0141] (Modification 3 of the first example of the second aspect) When the disaster condition is resolved and 5G services via PLMN1 are available, this restoration information shall be provided to the MME. The MME can then initiate the EPS to 5GS mobility registration procedure (Idle and Connected states) using the N26 interface as described in section 4.11.1.3.3 of 3GPP TS 23.502.

[0142] (Modification 4 of the first example of the second aspect) When the disaster condition is resolved and 5G services via PLMN1 are available, this restoration information shall be provided to the MME. The MME can then initiate idle mode mobility from EPS to 5GS using the N26 interface with data transfer as described in section 4.11.1.3.3 A of 3GPP TS 23.502.

[0143] (Modification 5 of the first example of the second aspect) When the disaster condition is resolved and 5G services via PLMN1 are available, this restoration information shall be provided to the MME. The MME may then initiate an EPS to 5GS mobility registration procedure (Idle) using the N26 interface with AMF re-allocation as described in section 4.11.1.3.4 of 3GPP TS 23.502.

[0144] (Modification 6 of the first example of the second aspect) In one example, a Home Public Land Mobile Network (HPLMN) sends a list of PLMNs, an EPS PLMN list, and the UE can register to the EPS if the UE determines that the 5GS of the currently registered PLMN is down in an existing NAS message or a new NAS message, such as a registration accept message or a UE configuration update message. When the UE receives the EPS PLMN list in an NAS message, it stores it. If the UE determines that it cannot register to the 5GS of an available PLMN, for example, if the 5GS of the currently registered PLMN is down and there are no other PLMNs available to provide 5G service, the UE selects a PLMN from the EPS PLMN list and attempts to attach to the PLMN for EPS service.

[0145] (Second example of the second aspect) In order to enable the 5G-only UE to perform disaster roaming to the EPS, it is beneficial for the 5G-only UE to know in advance whether the EPS supports the 5G-only UE to perform disaster roaming to the EPS before the 5G-only UE initiates disaster roaming service through the EPS. This example discloses a mechanism by which an eNodeB indicates to a 5G-only UE using an SIB whether disaster roaming of the 5G-only UE to an EPS is supported by the EPC.

[0146] Figure 6 shows an example of Abstract Syntax Notation 1 (ASN.1) extension on SIB for disaster roaming service. Figure 6 shows the system information block for disaster roaming service to EPS for 5G-only UE.

[0147] An eNodeB of a PLMN that supports disaster roaming of 5G-only UEs to an EPS broadcasts the following additional information parameters via the Broadcast Control Channel (BCCH): To indicate that disaster roaming service is supported in EPS, the supported general parameters or any other notation parameters are broadcast by the eNodeB in one of the SIB messages. There may be variations in the disaster roaming service supported in EPS, for example, the eNodeB supports either 1) disaster roaming coming from both EPS and 5GS is allowed, 2) only disaster roaming coming from EPS is allowed, or 3) only disaster roaming coming from 5GS is allowed. For example, 1) and 2) are used in situations where EPS roaming services are normally prohibited but are exceptionally permitted in the event of a disaster, and can be used in networks where domestic roaming in EPS is prohibited. -The generous acceptance parameter or any other notation parameter is broadcast by the eNodeB in one of the SIB messages to indicate that disaster roaming services can be provided by the EPS to users of UEs that do not have full access to the EPS. For example, a UE whose access restriction data is set as "E-UTRAN not allowed" in the subscriber data may be accepted by the EPS if liberal acceptance is indicated via the SIB. Supports either 1) disaster roaming coming from both EPS and 5GS is allowed, 2) disaster roaming coming from EPS only is allowed, or 3) disaster roaming coming from 5GS only is allowed. For example, 1) and 2) are used in situations where EPS roaming services are normally prohibited but are exceptionally permitted in the event of a disaster, and can be used in networks where domestic roaming in EPS is prohibited.

[0148] In one example, a wireless terminal corresponding to the UE receives information related to a System Information Block (SIB) from a wireless station, the SIB including at least one of information indicating that disaster roaming is available, information indicating that disaster roaming using both 4G and 5G services is available, and information indicating that disaster roaming can be accepted even if there is no subscriber data.

[0149] (Modification 1 of the second example of the second aspect) The NG-RAN may also broadcast new additional information over the BCCH, for example, SIB15 may broadcast the supported generic and permissive acceptance over the BCCH.

[0150] (Third example of the second aspect) In this example, a mechanism is disclosed for providing disaster roaming services in the situation where the UDM and / or HSS are unreachable due to a disaster situation. Figure 7 shows a scheme of a subscriber data backup configuration.

[0151] In this example, the following extensions to the 5GS and EPS are disclosed: (Subscriber Data Backup) -For subscriber data backup, new data storage devices, Backup UDM7502 and Backup HSS, have been created to support disaster roaming services for 5GS and EPS, respectively. -The backup UDM 7502 and backup HSS are located outside the PLMN and are isolated from the PLMN, so that a network failure within the PLMN that leads to a disaster condition does not affect the availability of the backup UDM and backup HSS. The subscriber data in the UDM 7501 is synchronized with the backup UDM 7502. The backup UDM 7502 can function as a Unified Data Repository (UDR) for unstructured data storage, as defined in Section 4.2.5 of 3GPP TS 23.501 (Patent Document 3). In this case, data synchronization can be based on the Nudsf service, as defined in 3GPP TS 23.502 (Patent Document 4). - Subscriber data in the HSS is synchronized with the backup HSS. -Together with the backup UDM 7502, the NW separated from the PLMN (for 5GS) can have an Authentication Server Function (AUSF), UDR, Policy Control Function (PCF) Application Function (AF) to provide connection services in the event of a disaster in 5GS. -A network separated from the PLMN (for EPS) along with a backup HSS can have an Authentication Centre (AuC), Policy and Charging Rule Function (PCRF), and AF to provide connectivity services in the event of a disaster. The UDM7501 can synchronize with a backup HSS to support disaster roaming services in EPS for 5GS subscribers. The HSS can be synchronized with a backup UDM7502 to support disaster roaming services with 5GS for EPS subscribers. IPsec, as described in 3GPP TS 33.210 (Patent Document 12), may be used to securely synchronize UE subscription data from the UDM 7501 to the backup UDM 7502 and backup HSS, as well as from the HSS to the backup HSS and backup UDM 7502.

[0152] In one example, a Unified Data Management (UDM) in a 5G System (5GS) synchronizes data with a backup UDM for the 5GS, which communicates with a backup Home Subscriber Server (HSS) for the Evolved Packet System (EPS).

[0153] In one example, a Home Subscriber Server (HSS) in an Evolved Packet System (EPS) synchronizes data with a backup HSS for the EPS, and the HSS communicates with a Unified Data Management (UDM) in a 5G System (5GS).

[0154] (Backup user identification information) New user identities, Backup IMSI, Backup Subscription Permanent Identifier (SUPI), and Backup Subscription Concealed Identifier (SUCI), are introduced to support disaster roaming services in case UDM and HSS are involved in a disaster in PLMN. The backup SUPI, backup SUCI, and backup IMSI back up the user identity information of the SUPI, SUCI, and IMSI, respectively. The backup SUPI and backup IMSI are stored in both the UE 3 and the UDM 7501. The UE 3 obtains the backup SUPI and backup IMSI during the registration procedure. The backup IMSI can be used when the UE 3 has disaster roaming service via EPS. The backup IMSI and, optionally, the backup SUPI are stored in both the UE 3 and the HSS. The UE 3 obtains the backup IMSI and the backup SUPI during the attach procedure or the tracking update procedure. The backup SUPI may be used when the UE 3 has disaster roaming service via 5GS. Any 3GPP node in the 5GS can route to the backup UDM using the backup SUPI or backup SUCI without traversing the (failed) PLMN. In one example, the backup SUPI has mcc and mnc values ​​other than the mcc and mnc of the HPLMN of the UE3. Any 3GPP node in the EPS can route to the backup HSS using the backup SUPI or backup SUCI without traversing the (failed) PLMN. In one example, the backup IMSI has mcc and mnc values ​​other than the mcc and mnc for the HPLMN of the UE3. FIG. 8 shows the scheme for backup user identities.

[0155] In one example, the user equipment corresponds to a UE that stores at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services over an Evolved Packet System (EPS).

[0156] In one example, the Unified Data Management (UDM) stores at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services via the Evolved Packet System (EPS).

[0157] In one example, a user equipment (UE) stores at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services via a 5G System (5GS).

[0158] In one example, a Home Subscriber Server (HSS) stores at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services over a 5G system (5GS).

[0159] (5GS registration procedure (for disaster roaming services)) This call flow in this example discloses a registration procedure in 5GS to send a backup SUPI and a backup IMSI to UE 3. The backup SUPI is used when PLMN 1 experiences a disaster situation and UDM 7501 is not reachable from any 5GS node. The backup IMSI is used when PLMN 1 experiences a disaster situation and HSS within PLMN 1 is not reachable from any EPS node.

[0160] Next, a detailed process of the third example of the second aspect will be described with reference to Figure 9. Figure 9 shows a scheme of a registration procedure for configuring a backup user identity in a UE.

[0161] Steps 0-1: UDM 7501 stores the backup SUPI and backup IMSI in the subscriber data for UE 3.

[0162] Steps 0-2. The subscriber data in UDM 7501 is synchronized with the subscriber data in backup UDM 7502. This can be done securely using IPsec, as described in 3GPP TS 33.210 (Patent Document 12).

[0163] Step 1. The UE 3 sends a registration request message including a backup UE ID support indication to the AMF 7001. The backup UE ID support indication indicates that the UE 3 supports storing a backup SUPI and a backup IMSI that can be used in disaster roaming services.

[0164] Step 2. Upon receiving a registration request message from UE3, if AMF7001 received a backup UE ID support indication from UE3 in the registration request message in step 1, AMF7001 sends a Nudm_UECM_Registration request message including the backup UE ID support indication to UDM7501.

[0165] Step 3. UDM7501 sends a Nudm_UECM_Registration response message to AMF7001.

[0166] Step 4. If AMF 7001 received a backup UE ID support indication from UE 3 in the registration request message in step 1, AMF 7001 sends a Nudm_SDM_Get request message including the backup UE ID support indication to UDM 7501. If the backup UE ID support indication was already sent to UDM 7501 in the Nudm_UECM_Registration request message in step 2, AMF 7001 cannot include the backup UE ID support indication again.

[0167] Step 5. When UDM7501 receives the Nudm_SDM_Get request message from AMF7001, it sends a Nudm_UECM_Response message including the backup SUPI and backup IMSI to AMF7001 only if UDM7501 received a backup UE ID support indication from AMF7001 in either the Nudm_UECM_Registration request message in step 2 or the Nudm_SDM_Get request message in step 4.

[0168] If integrity protection or / and confidentiality protection is required, the backup SUPI and backup IMSI are inserted into the SoR container and sent to the AMF 7001.

[0169] Step 6. When AMF 7001 receives the Nudm_SDM_Get response message from UDM 7501, it sends a registration accept message including the backup SUPI and backup IMSI to UE 3. The backup SUPI and backup IMSI are sent from UDM 7501 in a Steering of Roaming (SoR) container, and then AMF 7001 transparently sends the SoR container to UE 3 by setting the SoR container in the registration accept message.

[0170] When the UE 3 receives the registration acceptance message including the backup SUPI and backup IMSI, the UE 3 stores the backup SUPI and backup IMSI in a User Services Identity Module (USIM) or non-volatile memory within the UE 3. When the UE 3 receives the SoR container from the AMF 7001, the UE 3 decrypts the SoR container to obtain the backup SUPI and backup IMSI. The UE 3 then stores the backup SUPI and backup IMSI in the USIM or non-volatile memory within the UE 3.

[0171] The backup SUPI may be used by UE3 as a substitute for SUPI later in the registration procedure if PLMN1 experiences a disaster situation and UE3 initiates disaster roaming services with 5GS of another VPLMN. The backup IMSI may be used by UE3 as a substitute for IMSI later in the attachment procedure if PLMN1 experiences a disaster situation and UE3 initiates disaster roaming services with EPS of another VPLMN.

[0172] In one example, a core network node corresponding to AMF7001 of a 5G System (5GS) receives a backup radio terminal ID support indication from a ratio terminal corresponding to a UE. The core network node transmits the backup radio terminal ID support indication to a Unified Data Management (UDM) in the 5GS. The core network node transmits the backup radio terminal ID support indication to the UDM. The core network node receives at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMSI) from the UDM. The core network node transmits at least one of the backup SUPI and the backup IMSI to the radio terminal.

[0173] (EPS registration procedure (for disaster roaming services)) This call flow in this example discloses an attachment procedure in the EPS for sending a backup IMSI and optionally a backup SUPI to UE 3. The backup IMSI is used when PLMN 1 experiences a disaster situation and the HSS in PLMN 1 is not reachable from any EPS node. The backup SUPI is used when PLMN 1 experiences a disaster situation and the UDM 7501 is not reachable from any 5GS node.

[0174] Next, a detailed process of the third example of the second aspect will be described with reference to Fig. 10. Fig. 10 shows a scheme of an attach procedure for configuring a backup user identity in a UE.

[0175] Step 0-1. The HSS stores the backup IMSI and optionally the backup SUPI in the subscriber data of the UE3.

[0176] Steps 0-2. Subscriber data in the HSS is synchronized with subscriber data in the backup HSS. This can be done securely using IPsec, as described in 3GPP TS 33.210 (Patent Document 12).

[0177] Step 1. The UE 3 sends an Attach Request message or a TAU Request message to the MME, which includes a Backup UE Identity Support Indication. The Backup UE Identity Support Indication indicates that the UE 3 supports storing a backup IMSI and a backup SUPI that can be used in disaster roaming services.

[0178] Step 2. When AMF 7001 receives an attach request message or a TAU request message from UE 3, if the MME has received a backup UE ID support indication from UE 3 in the registration request message or TAU request message in step 1, AMF 7001 sends a location information update request message including the IMSI and backup UE ID support indication to the HSS.

[0179] Step 3. Upon receiving the Update Location Request message from the MME, the HSS sends an Update Location Response message to the MME, including a backup IMSI and optionally a backup SUPI, only if a backup UE ID support indication is received from the MME in the Update Location Request message from the MME in step 2.

[0180] Step 6. Upon receiving the Location Update message from the HSS, the MME sends an Attach Accept message or a TAU Accept message to the UE 3, including the backup IMSI and optionally the backup SUPI.

[0181] When UE3 receives an attach accept message or a TAU accept message including a backup IMSI and optionally a backup SUPI, UE3 stores the backup IMSI and optionally the backup SUPI in the USIM or non-volatile memory within UE3.

[0182] The backup IMSI may be used by UE3 as a substitute for IMSI later in the attachment procedure if PLMN1 experiences a disaster situation and UE3 initiates disaster roaming service with EPS of another VPLMN. The backup SUPI may be used by UE3 as a substitute for SUPI later in the registration procedure if PLMN1 experiences a disaster situation and UE3 initiates disaster roaming service with 5GS of another VPLMN.

[0183] In one example, a core network node corresponds to an MME in an Evolved Packet System (EPS) and receives a backup radio terminal ID support indication from a user equipment (UE). The core network node transmits the backup radio terminal ID support indication to a Home Subscriber Server (HSS). The core network node receives at least one of a backup Subscription Permanent Identifier (SUPI) and an International Mobile Subscriber Identity (IMSI) from the HSS. The core network node transmits at least one of the backup SUPI and the backup IMSI to the radio terminal.

[0184] (Registration procedure for disaster roaming service using backup SUPI for 5GS) This call flow in this example discloses a registration procedure in 5GS using a backup SUPI in case PLMN1 encounters a disaster situation and UDM7501 cannot be reached from any 5GS node. The backup SUPI is used by a 5GS in another PLMN (PLMN2) to have disaster roaming services using the backup SUPI.

[0185] Next, a detailed process of the third example of the second aspect will be described with reference to Fig. 11. Fig. 11 shows a scheme of a registration procedure for disaster roaming service with a backup SUPI.

[0186] Steps 0-1. Subscriber data in UDM 7501 is synchronized with subscriber data in backup UDM 7502. This can be done securely using IPsec, as described in 3GPP TS 33.210 (Patent Document 12).

[0187] Steps 0 to 2: In the third example of the second aspect, the UE 3 stores the backup SUPI based on the call flow of FIG. 9 or FIG.

[0188] Step 1. PLMN1 encounters a disaster situation. UDM7501 may not be reachable from any 5GC node due to the disaster.

[0189] Step 2. UE3 recognizes that PLMN1 is experiencing a network failure and decides to perform disaster roaming service using 5GS in PLMN2. The first example of the first aspect or the second example of the first aspect may be used to detect the network failure in PLMN1.

[0190] Step 3. The UE 3 sends a registration request message to the AMF 7002, including a user identity, a backup UE identity support indication, and a backup SUPI or backup SUCI. The backup UE identity support indication indicates that the UE 3 supports storing a backup SUPI and a backup IMSI that can be used in disaster roaming services. In addition to the user identity (which may be a 5G-GUTI, SUCI, or SUPI), a backup SUPI or backup SUCI is included as an alternative user identity for fetching subscriber data. The backup SUCI is calculated by the UE 3 based on the backup SUPI.

[0191] Step 4. When AMF7001 receives a registration request message from UE3, if AMF7001 has received a backup UE ID support indication and a backup SUPI or backup SUCI from UE3 in the registration request message in step 3, it sends a Nudm_UECM_Registration request message to backup UDM7502, including a backup UE ID support indication and a backup SUPI or backup SUCI.

[0192] Step 5. The backup UDM 7502 sends a Nudm_UECM_Registration response message to the AMF 7002.

[0193] Step 6. If AMF 7002 has received a backup UE ID support indication and a backup SUPI or backup SUCI from UE 3 in the registration request message in step 3, AMF 7001 sends a Nudm_SDM_Get request message including the backup UE ID support indication and the backup SUPI or backup SUCI to backup UDM 7502. If the backup UE ID support indication and the backup SUPI or backup SUCI have already been sent to backup UDM 7502 in the Nudm_UECM_Registration request message in step 4, AMF 7002 cannot include the backup UE ID support indication and the backup SUPI or backup SUCI again.

[0194] Step 7. When the backup UDM 7502 receives the Nudm_SDM_Get request message from the AMF 7002, it sends a Nudm_UECM_Response message containing disaster subscriber data to the AMF 7002.

[0195] Step 8. The AMF 7002 sends a registration acceptance message containing the 5G-GUTI as the user ID to the UE 3. The UE 3 has successfully registered with the PLMN 2 for the disaster roaming service.

[0196] Step 9. After the registration procedure to PLMN2 for disaster roaming service is completed, the UE has connectivity service via 5GS in PLMN2.

[0197] In one example, a core network node supports AMF 7002 in a roaming network and receives at least one of a backup radio terminal ID support indication, a backup Subscription Permanent Identifier (SUPI), and a backup Subscription Concealed Identifier (SUCI) from a radio terminal corresponding to a UE. The core network node transmits at least one of the backup radio terminal ID support indication, the backup SUPI, and the backup SUCI to a backup Unified Data Management (UDM). The core network node transmits at least one of the backup radio terminal ID support indication, the backup SUPI, and the backup SUCI to the backup UDM. The core network node receives subscriber data for disaster roaming from the backup UDM.

[0198] (Modification 11-1 of the third example of the second aspect) In step 4 of Figure 11, AMF7001 sends a Nudm_UECM_Registration request message to backup UDM7501 only if AMF7001 fails to send a Nudm_UECM_Registration request message to UDM7502 using the user ID (which may be SUCI or SUPI) received in the registration request message from UE3 in step 3.

[0199] (Modification 11-2 of the third example of the second aspect) UE3 may perform the registration procedure after UE3 detects a network failure of the EPS of PLMN1 while UE3 was attached to the EPS of PLMN1. In this case, data synchronization in steps 0-1 is performed between the HSS in PLMN1 and the backup UDM 7502 with subscriber data conversion from EPS subscription to 5GS subscription, and the failure in step 1 occurs in the EPS of PLMN1.

[0200] Registration procedure for disaster roaming service using backup IMSI in EPS This call flow in this example discloses an attach or TAU procedure in EPS using a backup IMSI in case PLMN1 experiences a disaster situation and the HSS in PLMN1 cannot be reached from any EPS node. The backup IMSI is used to have disaster roaming service with the EPS of another PLMN (PLMN2) using the backup IMSI.

[0201] Next, a detailed process of the third example of the second aspect will be described with reference to Fig. 12. Fig. 12 shows a scheme of an attach procedure or TAU procedure for disaster roaming service with a backup IMSI.

[0202] Steps 0-1. Subscriber data in the HSS in PLMN 1 is synchronized with subscriber data in the backup HSS. This can be done securely using IPsec, as described in 3GPP TS 33.210 (Patent Document 12).

[0203] Steps 0 to 2: The UE 3 stores the backup IMSI based on the call flow of FIG. 9 or FIG. 10 of the third example of the second aspect.

[0204] Step 1. PLMN1 encounters a disaster situation. The HSS in PLMN1 may not be reachable from any EPC node due to the disaster.

[0205] Step 2. UE3 recognizes that PLMN1 is experiencing a network failure and decides to perform disaster roaming service by EPS in PLMN2. The first example of the first aspect or the second example of the first aspect may be used to detect the network failure in PLMN1.

[0206] Step 3. The UE 3 sends an Attach Request message or a TAU Request message to the MME, including a user identity, a backup UE identity support indication, and a backup IMSI. The backup UE identity support indication indicates that the UE 3 supports storing a backup IMSI that can be used in disaster roaming services. In addition to the user identity (which may be a GUTI or IMSI), the backup IMSI is included as an alternative user identity for fetching subscriber data.

[0207] Step 4. When the MME in PLMN2 receives the attach request message or the TAU request message from UE3, if the AMF7001 receives the backup UE ID support indication and the backup IMSI from UE3 in the attach request message or the TAU request message in step 3, it sends a location information update message to the backup HSS, including the backup UE ID support indication and the backup IMSI.

[0208] Step 5. The backup HSS sends a location update response message to the MME in PLMN2 containing the disaster subscriber data.

[0209] Step 6. The MME in PLMN2 sends an Attach Accept message or a TAU Accept message containing the GUTI as the user identity to UE3. UE3 has successfully registered with PLMN2 for disaster roaming service.

[0210] Step 7. After the registration procedure to PLMN2 for disaster roaming service is completed, the UE has connectivity service via EPS in PLMN2.

[0211] In one example, a core network node corresponds to an MME in a roaming network and receives at least one of a backup wireless terminal ID, a support indication, and a backup International Mobile Subscriber Identity (IMSI) from a terminal corresponding to a UE. The core network node transmits the backup wireless terminal ID support indication and the backup IMSI to a backup Home Subscriber Server (HSS). The core network node receives subscriber data for disaster roaming from the backup HSS. The core network node transmits a message to the wireless terminal (UE).

[0212] (Modification 12-1 of the third example of the second aspect) In step 4 of Figure 12, only if the MME of PLMN2 cannot send a location update request message to the HSS of PLMN1 using the user ID (i.e., IMSI), the MME of PLMN2 sends a location update request message to the backup HSS.

[0213] (Modification 12-2 of the third example of the second aspect) After UE3 detects a network failure in 5GS of PLMN1 while UE3 is registered in 5GS of PLMN1, UE3 may perform an attach procedure or a tracking update procedure. In this case, data synchronization in steps 0 to 1 is performed between UDM7501 and backup HSS in PLMN1 by subscriber data conversion from 5GS subscription to EPS subscription, and the failure in step 1 occurs in 5GS of PLMN1.

[0214] (System Overview) FIG. 13 shows a schematic diagram of a mobile (cellular or wireless) telecommunications system 1 to which the above-described aspects can be applied.

[0215] The telecommunications system 1 represents an overview of a system capable of end-to-end communication, for example, a UE 3 (or user equipment, "mobile device", 3) communicating with other UE 3 or service servers in a data network 20 via respective (R)AN nodes 5 and a core network 7.

[0216] The (R)AN node 5 supports any radio access, including 5G radio access technology (RAT), E-UTRA radio access technology, Beyond 5G RAT, 6G RAT, and non-3GPP RAT, including wireless local area network (WLAN) technology defined by the Institute of Electrical and Electronics Engineers (IEEE).

[0217] The (R)AN node 5 may be divided into a Radio Unit (RU), a Distributed Unit (DU), and a Centralized Unit (CU). In some aspects, each of the units may be connected to each other to construct the (R)AN node 5 by adopting an architecture defined by the Open RAN (O-RAN) Alliance, where these units are referred to as the O-RU, O-DU, and O-CU, respectively.

[0218] The (R)AN node 5 may be divided into control plane functions and user plane functions. Furthermore, multiple user plane functions may be allocated to support communications. In some aspects, user traffic may be distributed across multiple user plane functions, with user traffic via each user plane function being aggregated at both the UE 3 and the (R)AN node 5. This divided architecture is sometimes referred to as "dual connectivity" or "multi-connectivity."

[0219] The (R)AN node 5 may also support communications using satellite access. In some aspects, the (R)AN node 5 may support satellite access and terrestrial access.

[0220] The (R)AN node 5 may also be referred to as an access node for non-wireless access, which includes fixed-line access as defined by the Broadband Forum (BBF) and optical access as defined by the Innovative Optical and Wireless Network (IOWN).

[0221] The core network 7 may include logical nodes (or "functions") for supporting communications in the telecommunications system 1. For example, the core network 7 may be a 5G Core Network (5GC) that includes, among other functions, control plane functions and user plane functions. Each function within a logical node may be considered a network function. A network function may be provided to another node by adapting a Service Based Architecture (SBA).

[0222] By adapting network virtualization technology defined as European Telecommunications Standards Institute, Network Functions Virtualization (ETSI NFV), network functions can be deployed as distributed, redundant, stateless, and scalable, providing services from several locations and several running instances of each location.

[0223] The core network 7 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0224] As is known, a UE 3 may move in and out of an area (i.e., a radio cell) served by an (R)AN node 5 as the UE 3 moves within the geographic area covered by the telecommunications system 1. To track the UE 3 and facilitate movement between different (R)AN nodes 5, the core network 7 comprises at least one access and mobility management function (AMF) 70. The AMF 70 communicates with the (R)AN nodes 5 coupled to the core network 7. In some core networks, a mobility management entity (MME) or mobility management node for Beyond 5G or a mobility management node for 6G may be used instead of the AMF 70.

[0225] The core network 7 also includes, among other things, a Session Management Function (SMF) 71, a User Plane Function (UPF) 72, a Policy Control Function (PCF) 73, an Authentication Server Function (AUSF) 74, a Unified Data Management (UDM) 75, and a Network Slice Selection Function (NSSF) 76. When a UE 3 is roaming in a visited Public Land Mobile Network (VPLMN), the home Public Land Mobile Network (HPLMN) of the UE 3 provides the roaming-out UE 3 with the UDM 75 and at least some of the functionality of the SMF 71, UPF 72, and PCF 73.

[0226] The UE 3 and each serving (R)AN node 5 are connected via an appropriate air interface (e.g., a so-called "Uu" interface, etc.). Adjacent (R)AN nodes 5 are connected to each other via appropriate (R)AN node 5-to-(R)AN node interfaces (e.g., a so-called "Xn" interface, etc.). Each (R)AN node 5 is also connected to nodes within the core network 7 (e.g., so-called core network nodes) via appropriate interfaces (e.g., so-called "N2" / "N3" interface(s)). The core network 7 also provides connectivity to a data network 20. The data network 20 can be the Internet, a public network, an external network, a private network, or an internal network of a PLMN. If the data network 20 is provided by a PLMN operator or a Mobile Virtual Network Operator (MVNO), IP Multimedia Subsystem (IMS) services can be provided by the data network 20. The UE 3 can be connected to the data network 20 using IPv4, IPv6, IPv4v6, Ethernet, or an unstructured data type. The data network can include an AAA 201.

[0227] The "Uu" interface may include the control plane of the Uu interface and the user plane of the Uu interface.

[0228] The user plane of the Uu interface is responsible for carrying user traffic between the UE 3 and the serving (R)AN node 5. The user plane of the Uu interface may have a layered structure with SDAP, PDCP, RLC, and MAC sublayers over the physical connection.

[0229] The control plane of the Uu interface is responsible for establishing, modifying, and releasing the connection between the UE 3 and the serving (R)AN node 5. The control plane of the Uu interface may have a hierarchical structure with RRC, PDCP, RLC, and MAC sublayers over the physical connection.

[0230] For example, the following messages are communicated over the RRC layer to support AS signaling: RRC Setup Request Message: This message is sent from the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the RRC Setup Request message: #Establishment cause and ue-identity. ue-Identity can take the value ng-5G-S-TMSI-Part1 or a random value. RRC Setup message: This message is sent from the (R)AN node 5 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the RRC Setup message: #Master cell group and radio bearer configuration RRC Setup Complete message: This message is sent from the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the RRC Setup Complete message: #guami-type, iab-node-indication, idle-measurements-available, mobility-state, ng-5G-S-TMSI-part2, registered-AMF, selected-PLMN-identity

[0231] The UE 3 and the AMF 70 are connected via an appropriate interface (such as the so-called N1 interface). The N1 interface is responsible for providing communication between the UE 3 and the AMF 70 to support NAS signaling. The N1 interface can be established via 3GPP access and non-3GPP access. For example, the following messages are communicated via the N1 interface: Registration Request Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the Registration Request message: #5GS Registration Type, ngKSI, 5GS Mobile Identity, Non-Current Native NAS Key Set Identifier, 5GMM Capabilities, UE Security Capabilities, Requested NSSAI, Last Visited Registration TAI, S1 UE Network Capabilities, Uplink Data Status, PDU Session Status, MICO Indication, UE Status, Additional GUTI, Allowed PDU Session Status, UE Usage Configuration, Requested DRX Parameters, EPS NAS Message Container, LADN Indication, Payload Container Type, Payload Container, Network Slicing Indication, 5GS Update Type, Mobile Station Class Mark 2, Supported Codecs, NAS Message Container, EPS Bearer Context Status, Requested Extended DRX Parameters, T3324 Value, UE Radio Capability ID, Requested Mapping NSSAI, Requested Additional Information, Requested WUS Assistance Information, N5GC Indication and Requested NB-N1 Mode DRX Parameters. Registration Accept Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the registration accept message: #5GS Registration Result, 5G-GUTI, Equivalent PLMN, TAI List, Allowed NSSAI, Rejected NSSAI, Configured NSSAI, 5GS Network Capability Support, PDU Session Status, PDU Session Reactivation Result, PDU Session Reactivation Result Error Cause, LADN Information, MICO Indication, Network Slicing Indication, Service Area List, T3512 Value, Non-3GPP Deregistration Timer Value, T3502 Value, Emergency Number List, Extended Emergency Number List, SOR Transparent Container, EAP Message, NSSAI Inclusion Mode, Operator Defined Access Category Definition, Negotiated DRX Parameters, Non-3GPP NW policy, EPS bearer context status, negotiated extended DRX parameters, T3447 value, T3448 value, T3324 value, UE radio capability ID, UE radio capability ID deletion indication, pending NSSAI, ciphering key data, CAG information list, aborted 5G-S-TMSI configuration, negotiated WUS assistance information, negotiated NB-N1 mode DRX parameters, and extended rejected NSSAI. Registration Complete Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the registration complete message: #SOR transparent container -Authentication Request Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the Authentication Request message: #ngKSI, ABBA, authentication parameter RAND (5G authentication challenge), authentication parameter AUTN (5G authentication challenge), and EAP message. -Authentication Response Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be taken together in the authentication response message: #Authentication response message identity, authentication response parameters, and EAP message. -Authentication Result Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be taken together in the Authentication Result Message: #ngKSI, EAP Message and ABBA. Authentication Failure Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be taken together in the Authentication Failure Message: #Authentication failure message identifier, 5GMM cause and authentication failure parameters. -Authentication Rejection Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be taken together in the authentication rejection message: #EAPMessage. - Service Request Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be taken together in the Service Request message: #ngKSI, Service Type, 5G-S-TMSI, Uplink Data Status, PDU Session Status, Allowed PDU Session Status, NAS Message Container. -Service Acceptance Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be taken together in the Service Acceptance Message: #PDU session status, PDU session reactivation result, PDU session reactivation result error cause, EAP message and T3448 value. - Service Rejection Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be taken together in the Service Rejection Message: #5GMM cause, PDU session status, T3346 value, EAP message, T3448 value, and CAG information list. Configuration Update Command Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be taken together in the Configuration Update Command message: # Configuration update indication, 5G-GUTI, TAI list, allowed NSSAI, service area list, network full name, network short name, local time zone, universal time and local time zone, network daylight saving time, LADN information, MICO indication, network slicing indication, configured NSSAI, rejected NSSAI, operator defined access category definition, SMS indication, T3447 value, CAG information list, UE radio capability ID, UE radio capability ID deletion indication, 5GS registration result, aborted 5G-S-TMSI configuration, additional configuration indication, and extended rejected NSSAI. Configuration Update Complete message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be taken together in the Configuration Update Complete message: #Configuration update complete message identification information.

[0232] (User equipment (UE)) FIG. 14 is a block diagram illustrating the main components of a mobile device 3 (UE 3). As illustrated, the UE 3 includes a transceiver circuit 31 operable to transmit signals to and receive signals from connected node(s) via one or more antennas 32. The UE 3 may also include a user interface 34 for inputting or outputting information from the outside. Although not necessarily shown in the figure, the UE 3 may have all the usual functions of a conventional mobile device, which may be provided by any one or any combination of hardware, software, and firmware, as needed. The software may be pre-installed in memory and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The control unit 33 controls the operation of the UE 3 in accordance with software stored in the memory 36. The software includes, among other things, an operating system 361 and a communication control module 362 having at least one transceiver control module 3621. The communications control module 362 (using its transceiver control module 3621) is responsible for processing (generating / sending / receiving) signaling and uplink / downlink data packets between the UE 3 and other nodes, such as the (R)AN node 5 and the AMF 70. Such signaling may include, for example, appropriately formatted signaling messages related to access and mobility management procedures (for the UE 3) (e.g., registration request messages and associated response messages). The controller 33 interacts with one or more Universal Subscriber Identity Modules (USIMs) 35. If multiple USIMs 35 are installed, the controller 33 may activate only one USIM 35 or multiple USIMs 35 simultaneously.

[0233] The UE 3 may, for example, support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). UE3 may be, for example, an item of equipment and / or energy-related machinery for production or manufacturing (e.g., equipment or machinery such as boilers; engines; turbines; solar panels; wind turbines; hydroelectric generators; thermal power plants; nuclear generators; batteries; nuclear systems and / or related equipment; heavy electrical equipment; pumps including vacuum pumps; compressors; fans; blowers; hydraulic equipment; pneumatic equipment; metalworking machinery; manipulators; robots and / or their application systems; tools; molds or dies; rolls; material handling equipment; textile machinery; sewing machines; printing and / or related machinery; paper converting machinery; chemical machinery; mining and / or construction machinery and / or related equipment; machinery and / or implements for agriculture, forestry and / or fisheries; safety and / or environmental protection equipment; tractors; precision bearings; chains; gears; power transmission equipment; lubrication equipment; valves; pipe fittings; and / or application systems for any of the aforementioned equipment or machines).

[0234] The UE 3 may be, for example, an item of transportation equipment (e.g., transportation equipment such as railcars; automobiles; motorcycles; bicycles; trains; buses; carts; rickshaws; ships or other watercraft; aircraft; rockets; satellites; drones; balloons, etc.).

[0235] The UE 3 may be, for example, an information and communication equipment item (eg, information and communication equipment such as electronic computers and related equipment; communications and related equipment; electronic components, etc.).

[0236] The UE3 may be, for example, a refrigerator, a refrigerator application product, a goods and / or service industry equipment item, a vending machine, an automated service machine, an office machine, a consumer electronic device and an electronic appliance (e.g., consumer appliances such as audio equipment; video equipment; speakers; radios; televisions; microwave ovens; rice cookers; coffee machines; dishwashers; washing machines; dryers; electronic fans or related appliances; vacuum cleaners, etc.).

[0237] The UE 3 may be, for example, an electrical application system or equipment (eg, an electrical application system or equipment such as an X-ray system; a particle accelerator; a radioisotope equipment; a sonic equipment; an electromagnetic application equipment; an electrical application equipment, etc.).

[0238] The UE3 may be, for example, an electronic lamp, lighting fixture, measuring instrument, analyzer, tester, or surveying or sensing equipment (e.g., surveying or sensing equipment such as smoke detectors; motion sensors; radio frequency tags, etc.), a wristwatch or watch, inspection equipment, optical devices, medical equipment and / or systems, weapons, cutlery items, hand tools, etc.

[0239] UE3 may be, for example, a wireless-equipped personal digital assistant or related equipment (such as a wireless card or module designed to be attached to or inserted into another electronic device (e.g., a personal computer, electrical measuring instrument)).

[0240] The UE3 may be part of a device or system that uses various wired and / or wireless communication technologies to provide the applications, services, and solutions described below in relation to the "internet of things (IoT)."

[0241] Internet of Things devices (or "Things") may be equipped with appropriate electronics, software, sensors, network connections, etc. that enable these devices to collect and exchange data with each other and other communicating devices. IoT devices may comprise automated equipment that follows software instructions stored in internal memory. IoT devices may operate without the need for human supervision or interaction. IoT devices may also remain stationary and / or inactive for extended periods of time. IoT devices may be implemented as part of (typically) stationary equipment. IoT devices may also be incorporated into non-stationary equipment (e.g., vehicles) or attached to animals or people being monitored / tracked.

[0242] It will be appreciated that IoT technologies may be implemented on any communication device that can connect to a communication network to send / receive data, whether such communication device is controlled by human input or by software instructions stored in memory.

[0243] It will be appreciated that an IoT device may also be referred to as a Machine-Type Communication (MTC) device, a Machine-to-Machine (M2M) communication device, or a Narrow Band-IoT UE (NB-IoT UE). It will be appreciated that a UE 3 may support one or more IoT or MTC applications.

[0244] The UE 3 may be a smartphone or a wearable device (e.g., smart glasses, a smart watch, a smart ring, or a hearable device).

[0245] The UE3 may be a car, a connected car, an autonomous car, a vehicle device, a motorcycle, or a V2X (Vehicle to Everything) communication module (e.g., a vehicle-to-vehicle communication module, a vehicle-to-infrastructure communication module, a vehicle-to-pedestrian communication module, and a vehicle-to-network communication module).

[0246] ((R)AN node) FIG. 15 is a block diagram illustrating the main components of an exemplary (R)AN node 5, e.g., a base station (eNB in ​​LTE, gNB in ​​5G, later 5G base station, 6G base station). As shown, the (R)AN node 5 includes transceiver circuitry 51 operable to transmit signals to and receive signals from connected UE(s) 3 via one or more antennas 52, and to transmit signals to and receive signals from other network nodes (directly or indirectly) via a network interface 53. A controller 54 controls operation of the (R)AN node 5 in accordance with software stored in memory 55. The software may be pre-installed in memory and / or may be downloaded, for example, over a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 551 and a communications control module 552 having at least a transceiver control module 5521.

[0247] The communications control module 552 (using its transceiver control sub-module) is responsible for handling (generating / sending / receiving) signaling between (e.g., directly or indirectly) the (R)AN node 5 and other nodes, e.g., between a UE 3, another (R)AN node 5, an AMF 70, a UPF 72, etc. The signaling may include, for example, appropriately formatted signaling messages related to the radio connection and connectivity with the core network 7 (for a particular UE 3), in particular related to connection establishment and maintenance (e.g., RRC connection establishment and other RRC messages), NG Application Protocol (NGAP) messages (i.e., messages over the N2 reference point) and Xn application protocol (XnAP) messages (i.e., messages over the Xn reference point), etc. Such signaling may also include, for example, broadcast information (e.g., master information and system information) in the transmit case.

[0248] The control unit 54, when implemented, is also configured (by software or hardware) to handle related tasks such as UE mobility estimation and / or movement trajectory estimation.

[0249] The (R)AN node 5 can support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0250] The current RAN 501 and the candidate RAN 502 may have the same components as the (R)AN node 5. The (R)AN node 5 may also be referred to as a RAN node, a RAN, an (R)AN, etc.

[0251] (System overview of (R)AN Node 5 based on O-RAN architecture) FIG. 16 illustrates schematically an (R)AN node 5 based on an O-RAN architecture to which aspects of the (R)AN node 5 are applicable.

[0252] The (R)AN node 5 based on the O-RAN architecture represents a system overview in which the (R)AN node is divided into a Radio Unit (RU) 60, a Distributed Unit (DU) 61, and a Centralized Unit (CU) 62. In some aspects, each unit may be combined. For example, the RU 60 may be combined with the DU 61 as a combined / combined unit, and the DU 61 may be combined with the CU 62 as another combined / combined unit. Any functionality described in the description of a unit (e.g., one of the RU 60, DU 61, and CU 62) may be implemented in the combined / combined unit. Furthermore, the CU 62 may be separated into two functional units, such as a CU Control plane (CP) and a CU User plane (UP). The CU CP has the control plane function in the (R)AN node 5. The CU UP has the user plane function in the (R)AN node 5. Each CU CP is connected to the CU UP via an appropriate interface "E1."

[0253] The UE 3 and each serving RU 60 are connected via an appropriate air interface (e.g., the so-called "Uu" interface, etc.). Each RU 60 is connected to a DU 61 via an appropriate interface (e.g., the so-called "fronthaul," "open fronthaul," "F1" interface, etc.). Each DU 61 is connected to a CU 62 via an appropriate interface (e.g., the so-called "midhaul," "open midhaul," "E2" interface, etc.). Each CU 62 is also connected to a node in the core network 7 (e.g., a so-called core network node) via an appropriate interface (e.g., the so-called "backhaul," "open backhaul," "N2" / "N3" interface(s)), etc. The user plane part of the DU 61 can also be connected to the core network node 7 via an appropriate interface (e.g., the so-called "N3" interface(s)).

[0254] Depending on the functionality divided between the RU 60, DU 61, and CU 62, each unit provides a portion of the functionality provided by the (R)AN node 5. For example, the RU 60 may provide functionality for communicating with the UE 3 over the air interface, the DU 61 may provide functionality for supporting the MAC and RLC layers, and the CU 62 may provide functionality for supporting the PDCP, SDAP, and RRC layers.

[0255] (Radio Unit (RU)) FIG. 17 is a block diagram illustrating the main components of an exemplary RU 60, e.g., the RU portion of a base station (e.g., an eNB in ​​LTE, a gNB in ​​5G, a later 5G base station, or a 6G base station). As shown, the RU 60 includes a transceiver circuit 601 operable to transmit signals to and receive signals from connected UE(s) 3 via one or more antennas 602 and to transmit and receive signals to and from other network nodes or units (directly or indirectly) via a network interface 603. A controller 604 controls the operation of the RU 60 according to software stored in memory 605. The software may be pre-installed in the memory and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 6051 and a communications control module 6052 having at least a transceiver control module 60521.

[0256] The communications control module 6052 (using its transceiver control sub-module) is responsible for handling (generating / sending / receiving) signaling between the RU 60 and other nodes or units (e.g., directly or indirectly), such as a UE 3, another RU 60, or a DU 61. The signaling may include, for example, appropriately formatted signaling messages related to the radio connection and connection with the RU 60 (for a particular UE 3), in particular related to the MAC and RLC layers.

[0257] When implemented, the controller 604 is also configured (by software or hardware) to handle related tasks such as UE mobility estimation and / or movement trajectory estimation.

[0258] The RU 60 can support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0259] As mentioned above, the RU 60 can be integrated / combined with the DU 61 as an integrated / combined unit. Any function described for the RU 60 can be implemented in the integrated / combined unit.

[0260] (Distributed Unit (DU)) FIG. 18 is a block diagram illustrating the main components of an exemplary DU 61, e.g., a DU section of a base station (e.g., an eNB in ​​LTE, a gNB in ​​5G, a later 5G base station, or a 6G base station). As shown, the device includes a transceiver circuit 611 operable to transmit signals to and receive signals from other nodes or units (including the RU 60) via a network interface 612. A controller 613 controls the operation of the DU 61 in accordance with software stored in memory 614. The software may be pre-installed in memory 614 and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 6141 and a communications control module 6142 having at least a transceiver control module 61421. The communication control module 6142 (using its transceiver control module 61421) is responsible for handling (generating / sending / receiving) signaling between the DU 61 and other nodes or units, for example, between the RU 60 and other nodes and units.

[0261] The DU 61 can support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). As mentioned above, the RU 60 can be integrated / combined as an integrated / combined unit with the DU 61 or the CU 62. Any function in the description of the DU 61 can be implemented in the above integrated / combined unit.

[0262] (Centralized Unit (CU)) FIG. 19 is a block diagram illustrating the main components of an exemplary CU 62, e.g., the CU portion of a base station (e.g., an eNB in ​​LTE, a gNB in ​​5G, a later 5G base station, or a 6G base station). As shown, the device includes a transceiver circuit 621 operable to transmit signals to and receive signals from other nodes or units (including the DU 61) via a network interface 622. A controller 623 controls the operation of the CU 62 in accordance with software stored in memory 624. The software may be pre-installed in memory 624 and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 6241 and a communications control module 6242 having at least a transceiver control module 62421. The communication control module 6242 (using its transceiver control module 62421) is responsible for handling (generating / sending / receiving) signaling between the CU 62 and other nodes or units, for example, between the DU 61 and other nodes and units.

[0263] The CU 62 can support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0264] As mentioned above, the CU 62 may be integrated / combined with the DU 61 as an integrated / combined unit. Any functionality described for the CU 62 may be implemented in the integrated / combined unit.

[0265] (AMF) 20 is a block diagram illustrating the main components of the AMF 70. As shown, the device includes a transceiver circuit 701 operable to transmit signals to and receive signals from other nodes (including UE 3, NSSF 76) via a network interface 702. A controller 703 controls the operation of the AMF 70 in accordance with software stored in memory 704. The software may be pre-installed in memory 704 and / or may be downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7041 and a communications control module 7042 having at least a transceiver control module 70421. The communications control module 7042 (using its transceiver control module 70421) is responsible for processing (generating / sending / receiving) signaling between the AMF 70 and other nodes, such as the UE 3 (e.g., via (R)AN node 5) and other core network nodes (including core network nodes in the UE 3's HPLMN when the UE 3 is roaming in). Such signaling may include, for example, appropriately formatted signaling messages related to access and mobility management procedures (for the UE 3) (e.g., registration request messages and associated response messages).

[0266] The AMF 70 can support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). The AMF 7001 and AMF 7002 may have the same components as the AMF 70.

[0267] (PCF) 21 is a block diagram illustrating the major components of the PCF 73. As shown, the device includes a transceiver circuit 731 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 732. A controller 733 controls the operation of the PCF 73 in accordance with software stored in memory 734. The software may be pre-installed in the memory 734 and / or may be downloaded, for example, via a telecommunications network or from a removable storage device (e.g., a removable memory device (RMD)). The software includes, among other things, an operating system 7341 and a communications control module 7342 having at least a transceiver control module 73421. The communications control module 7342 (using its transceiver control module 73421) is responsible for handling (generating / sending / receiving) signaling between the PCF 73 and other nodes, such as the AMF 70 and other core network nodes (including core network nodes in the HPLMN of the UE 3 when the UE 3 is roaming in). Such signaling may include, for example, appropriately formatted signaling messages (e.g., HTTP restful methods based on service-based interfaces) related to policy management procedures (for the UE 3).

[0268] The PCF 73 can support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). The PCF 7301 and the PCF 7302 may have the same components as the PCF 73.

[0269] (AUSF) 22 is a block diagram illustrating the major components of the AUSF 74. As shown, the device includes a transceiver circuit 741 operable to transmit signals to and receive signals from other nodes (including the UDM 75) via a network interface 742. A controller 743 controls the operation of the AUSF 74 in accordance with software stored in memory 744. The software may be pre-installed in the memory 744 and / or may be downloaded, for example, via a telecommunications network or from a removable storage device (e.g., a removable memory device (RMD)). The software includes, among other things, an operating system 7441 and a communications control module 7442 having at least a transceiver control module 74421. The communications control module 7442 (using its transceiver control module 74421) is responsible for handling (generating / sending / receiving) signaling between the AUSF 74 and other nodes, such as the AMF 70 and other core network nodes (including core network nodes in the HPLMN of the UE 3 when the UE 3 is roaming in). Such signaling may include, for example, appropriately formatted signaling messages (e.g., HTTP restful methods based on service-based interfaces) related to policy management procedures (for the UE 3).

[0270] The AUSF74 can support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0271] (UDM) FIG. 23 is a block diagram illustrating the main components of the UDM 75. As shown, the device includes a transceiver circuit 751 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 752. A controller 753 controls the operation of the UDM 75 according to software stored in a memory 754. The software may be pre-installed in the memory 754 and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7541 and a communications control module 7542 having at least a transceiver control module 75421. The communications control module 7542 (using its transceiver control module 75421) is responsible for processing (generating / sending / receiving) signaling between the UDM 75 and other nodes, for example, the AMF 70 and other core network nodes (including core network nodes in the UE 3's VPLMN when the UE 3 is roaming out). Such signaling may include, for example, appropriately formatted signaling messages (for UE 3) related to mobility management procedures (e.g., HTTP restful methods based on service-based interfaces).

[0272] The UDM 75 can support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0273] (NSSF) FIG. 24 is a block diagram illustrating the main components of the NSSF 76. As shown, the device includes a transceiver circuit 761 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 762. A controller 763 controls the operation of the NSSF 76 in accordance with software stored in a memory 764. The software may be pre-installed in the memory 764 and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7641 and a communications control module 7642 having at least a transceiver control module 76421. The communications control module 7642 (using its transceiver control module 76421) is responsible for processing (generating / sending / receiving) signaling between the NSSF 76 and other nodes, for example, the AMF 70 and other core network nodes (including core network nodes in the UE 3's VPLMN when the UE 3 is roaming out). Such signaling may include, for example, appropriately formatted signaling messages (for UE 3) related to mobility management procedures (e.g., HTTP restful methods based on service-based interfaces).

[0274] The NSSF 76 can support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0275] The exemplary embodiments disclosed above can be described in whole or in part as follows, without limitation.

[0276] Variations and Alternatives Having described detailed embodiments above, those skilled in the art will appreciate that several modifications and alternatives can be made to the above embodiments while still benefiting from the disclosure embodied therein. By way of example only, some of these alternatives and modifications are now described.

[0277] In the above description, for ease of understanding, the UE 3 and network devices are described as having several separate modules (such as a communications control module). These modules may be provided in this manner in certain applications, for example, where an existing system is modified to implement the present disclosure, but in other applications, such as systems designed from the beginning with the features of the present invention in mind, these modules may be incorporated into an overall operating system or code, and therefore may not be identified as separate entities. These modules may also be implemented as software, hardware, firmware, or a mixture of these.

[0278] Each control unit may comprise any suitable form of processing circuitry, including (but not limited to), for example, one or more hardware-implemented computer processors, microprocessors, central processing units (CPUs), arithmetic logic units (ALUs), input / output (IO) circuitry, internal memory / cache (program and / or data), processing registers, communication buses (e.g., control buses, data buses, and / or address buses), direct memory access (DMA) functions, hardware or software-implemented counters, pointers, and / or timers, etc.

[0279] In the above embodiments, several software modules have been described. As will be appreciated by those skilled in the art, the software modules may be provided in compiled or uncompiled form and may be provided to the UE 3 and network devices as signals over a computer network or on a recording medium. Furthermore, the functions performed by some or all of this software may be performed using one or more dedicated hardware circuits. However, the use of software modules is preferred because it facilitates updating the UE 3 and network devices to update their functionality.

[0280] In the above embodiments, 3GPP wireless communication (radio access) technology is used. However, any other wireless communication technology (e.g., WLAN, Wi-Fi, WiMAX, Bluetooth, etc.) and other fixed line communication technology (e.g., BBF access, cable access, optical access, etc.) can also be used according to the above embodiments.

[0281] Items of user equipment may include, for example, communication devices such as mobile phones, smartphones, user equipment, personal digital assistants, laptop / tablet computers, web browsers, e-book readers, etc. Such mobile (or more generally fixed) devices are typically operated by a user, although so-called "Internet of Things" (IoT) devices and similar machine-type communication (MTC) devices may also be connected to the network. For simplicity, this application refers to mobile devices (or UE) in the description, but it will be understood that the described techniques may be implemented on any communication device (mobile and / or generally fixed) that can connect to a communication network to send and receive data, regardless of whether such communication device is controlled by human input or software instructions stored in memory.

[0282] Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

[0283] As will be appreciated by those skilled in the art, the present disclosure may be embodied as a method and a system, and thus may take the form of an entirely hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects.

[0284] It will be understood that each block of the block diagrams may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to produce a machine, whereby the instructions, executed by the processor of the computer or other programmable data processing apparatus, generate means for implementing the functions / acts specified in one or more blocks of the flowcharts and / or block diagrams. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., multiple microprocessors, one or more microprocessors, or any other such configuration.

[0285] The methods or algorithms described in connection with the examples disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC.

[0286] The previous description of the disclosed examples is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these examples will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other examples without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0287] Although the present disclosure has been illustrated and described in detail with reference to exemplary embodiments thereof, the present disclosure is not limited to these embodiments. Those skilled in the art will understand that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as defined herein. For example, the above embodiments are not limited to 5GS, and these embodiments are also applicable to communication systems other than 5GS (e.g., 6G systems, 5G Beyond systems).

[0288] (Addendum) The exemplary embodiments disclosed above may be explained in whole or in part as follows, but are not limited to these. (Appendix 1) A radio station, Memory and configured to access memory, Sending a setup request message to a first core network node in the first network, the setup request message including information about a list of connected networks; receiving a setup response message from a first core network node, the setup response message including at least one of information about a list of roaming networks and information about a priority of the roaming networks; Detecting a failure in a connection between the first core network node or another core network node in the first network; and at least one processor configured to transmit to a wireless terminal at least one of information related to a disaster state of a first network, information about the first network, information about a list of roaming networks, and information about a priority of the roaming networks. (Appendix 2) 2. The radio station of claim 1, wherein at least one of the information related to the disaster state of the first network, the information about the first network, the list of roaming networks, and the information about the priority of the roaming networks is included in a System Information Block (SIB) message or a Radio Resource Control Release message. (Appendix 3) a first core network node in a first network, Memory and configured to access memory, receiving a setup request message from the wireless station, the setup request message including information about a list of connected networks; and at least one processor configured to transmit a setup response message to a wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about priorities of the disaster roaming networks. (Appendix 4) A wireless terminal, Memory and configured to access memory, receiving at least one of information related to a disaster state of the first network, information about the first network, information about a list of roaming networks, and information about priorities for the roaming networks from the wireless station; A wireless terminal comprising at least one processor specifically configured to send a registration request message with parameters used to initiate disaster roaming services to a second core network node in a roaming network. (Appendix 5) 1. A method for a radio station, comprising: means for transmitting a setup request message to a first core network node in a first network, the setup request message including information about a list of connected networks; means for receiving a setup response message from a first core network node, the setup response message including at least one of information about a list of roaming networks and information about a priority of the roaming networks; means for detecting a failure of a connection between the first core network node or another core network node in the first network; means for transmitting at least one of information related to a disaster condition of the first network, information about the first network, information about a list of roaming networks, and information about a priority of the roaming networks to the wireless terminal. (Appendix 6) The method of claim 5, wherein at least one of the information related to the disaster state of the first network, the information about the first network, the list of roaming networks, and the information about the priority of the roaming PLMN is included in a System Information Block (SIB) message or a Radio Resource Control Release message. (Appendix 7) 1. A method for a first core network node in a first network, comprising: means for receiving a setup request message from a wireless station, the setup request message including information about a list of connected networks; means for transmitting a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about priorities of the disaster roaming networks. (Appendix 8) 1. A method for a wireless terminal, comprising: means for receiving from the wireless station at least one of information related to a disaster state of the first network, information about the first network, information about a list of roaming networks, and information about a priority of the roaming networks; means for transmitting a registration request message with parameters used to initiate disaster roaming services to a second core network node in the roaming network. (Appendix 9) a first core network node in a first network, Memory and configured to access memory, receiving a setup request message from the wireless station, the setup request message including information about a list of connected networks; transmitting a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about priorities of the disaster roaming networks; receiving information from a second core network node in the first network indicating a need for minimizing service interruption; and at least one processor configured to transmit information including at least one of a new cause parameter, a disaster status indication parameter, and an available service parameter to the wireless station. (Appendix 10) 1. A method for a first core network node in a first network, comprising: means for receiving a setup request message from a wireless station, the setup request message including information about a list of connected networks; means for transmitting a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about priorities of the disaster roaming networks; means for receiving information from a second core network node in the first network indicating a need for minimizing service interruption; means for transmitting information to the wireless station, the information including at least one of a new cause parameter, a disaster status indication parameter, and an available service parameter. (Appendix 11) A wireless terminal, Memory and configured to access memory, Decided to provide disaster-related roaming services, transmitting a Radio Resource Control (RRC) Setup Request message to the wireless station, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; receiving at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks from the wireless station; transmitting an RRC setup complete message to the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has the capability to support disaster-related roaming services, and information related to a disaster state of the first network; transmitting information related to the roaming network to the wireless station; and at least one processor configured to transmit Non Access Stratum (NAS) container information to the wireless station, the NAS container information including registration request information that indicates that the wireless terminal has capability to support disaster-related roaming services and that includes at least one of information related to a disaster condition of the first network. (Appendix 12) A radio station, Memory and configured to access memory, receiving a Radio Resource Control (RRC) setup request message from the wireless terminal, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; transmitting at least one of information related to a disaster state of the first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks to the wireless terminal; receiving an RRC setup complete message from the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has capability to support disaster-related roaming services, and information related to a disaster state of the first network; receiving information related to a roaming network from the wireless terminal; receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; and at least one processor configured to transmit a registration request message to a third core network node in a roaming network (PLMN2), the registration request message including at least one of information indicating that the wireless terminal has an ability to support disaster-related roaming services and information related to a disaster state of the first network. (Appendix 13) a fourth core network node in a first network (PLMN1) associated with the disaster, Memory and configured to access memory, receiving a message from a third core network node in the roaming network, the message including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; receiving, from a third core network node, a message including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster state of the first network; and a fourth core network node comprising: at least one processor configured to send a message including the subscriber data to the third core network node. (Appendix 14) a third core network node in the second network, Memory and configured to access memory, receiving a registration request message from the wireless terminal, the registration request message including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to a disaster condition of the first network; transmitting a message to a fourth core network node in the first network related to the disaster, the message including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster state of the first network; transmitting a message to a fourth core network node, the message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster condition of the first network; and at least one processor configured to receive a message including subscriber data from the fourth core network node. (Appendix 15) 1. A method for a wireless terminal, comprising: A means for determining whether to provide disaster-related roaming services; means for transmitting a Radio Resource Control (RRC) setup request message to a wireless station, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; means for receiving from the wireless station at least one of information related to a disaster state of the first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; means for transmitting an RRC setup complete message to the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has a capability to support disaster-related roaming services, and information related to a disaster state of the first network; means for transmitting information related to a roaming network to a wireless station; and means for transmitting Non Access Stratum (NAS) container information to the wireless station, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services of the first network and information related to the disaster condition. (Appendix 16) 1. A method for a radio station, comprising: means for receiving, from the wireless terminal, a Radio Resource Control (RRC) setup request message including information indicating that the wireless terminal has capability to support disaster-related roaming services; means for transmitting at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of roaming networks to the wireless terminal; means for receiving an RRC setup complete message from the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has a capability to support disaster-related roaming services, and information related to a disaster state of the first network; means for receiving information relating to a roaming network from a wireless terminal; means for receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; means for transmitting a registration request message to a third core network node in the roaming network, the registration request message including at least one of information indicating that the wireless terminal has an ability to support disaster-related roaming services and information related to a disaster condition of the first network. (Appendix 17) 1. A method for a fourth core network node in a first network associated with a disaster, comprising: means for receiving, from a third core network node in the roaming network, a message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster condition of the first network; means for receiving, from a third core network node, a message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster state of the first network; means for transmitting a message including the subscriber data to a third core network node. (Appendix 18) A method for a third core network node in a second network, comprising: means for receiving, from the wireless terminal, a registration request message including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; means for transmitting a message to a fourth core network node in the first network related to the disaster, the message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster state of the first network; means for transmitting a message to a fourth core network node, the message including at least one of information indicating that the wireless terminal has a capability to support disaster-related roaming services and information related to a disaster state of the first network; means for receiving a message including the subscriber data from the fourth core network node. (Appendix 19) A wireless terminal, Memory and configured to access memory, Decided to provide disaster-related roaming services, transmitting a Radio Resource Control (RRC) re-establishment request message to the wireless station, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; receiving at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks from the wireless station; transmitting an RRC setup complete message to the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has the capability to support disaster-related roaming services, and information related to a disaster state of the first network; transmitting information related to the roaming network to the wireless station; and at least one processor configured to transmit Non Access Stratum (NAS) container information to the wireless station, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network. (Appendix 20) A radio station, Memory and configured to access memory, receiving a Radio Resource Control (RRC) re-establishment request message from the wireless terminal, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; transmitting at least one of information related to a disaster state of the first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks to the wireless terminal; receiving an RRC setup complete message from the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has capability to support disaster-related roaming services, and information related to a disaster state of the first network; receiving information related to a roaming network from the wireless terminal; receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; and at least one processor configured to transmit a registration request message to a third core network node in a roaming network, the registration request message including at least one of information indicating that the wireless terminal has an ability to support disaster-related roaming services and information related to a disaster state of the first network. (Appendix 21) 1. A method for a wireless terminal, comprising: A means for determining whether to provide disaster-related roaming services; means for transmitting a Radio Resource Control (RRC) re-establishment request message to the wireless station, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; means for receiving from the wireless station at least one of information related to a disaster state of the first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; means for transmitting an RRC setup complete message to the wireless terminal, the RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has a capability to support disaster-related roaming services, and information related to a disaster state of the first network; means for transmitting information related to a roaming network to a wireless station; and means for transmitting Non Access Stratum (NAS) container information to the wireless terminal, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to a disaster condition of the first network. (Appendix 22) 1. A method for a radio station, comprising: means for receiving, from the wireless terminal, a Radio Resource Control (RRC) re-establishment request message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; means for transmitting at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of roaming networks to the wireless terminal; means for receiving, from the wireless terminal, an RRC setup complete message including at least one of information about the first network, information indicating that the wireless terminal has capability to support disaster related roaming services, and information related to a disaster state of the first network; means for receiving information relating to a roaming network from a wireless terminal; means for receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of information indicating that the wireless terminal has capability to support disaster-related roaming services and information related to a disaster condition of the first network; means for transmitting a registration request message to a third core network node in the roaming network (PLMN2), the registration request message including at least one of information indicating that the wireless terminal has an ability to support disaster-related roaming services and information related to the disaster condition of the first network. (Appendix 23) A wireless terminal in a 5G network, Memory and configured to access memory, Decided to provide disaster-related roaming services, and at least one processor configured to transmit information indicating that the wireless terminal has the capability to support disaster-related roaming services to a fifth core network node in a 4G network. (Appendix 24) A sixth core network node in a 5G network, Memory and configured to access memory, receiving information from a fifth core network node in the 4G network indicating that the wireless terminal has capability to support disaster-related roaming services; and at least one processor configured to transmit the subscriber data to the fifth core network node. (Appendix 25) 1. A method for a wireless terminal in a 5G network, comprising: A means for determining whether to provide disaster-related roaming services; means for transmitting information indicating that the wireless terminal has the capability to support disaster-related roaming services to a fifth core network node in the 4G network. (Appendix 26) 1. A method for a sixth core network node in a 5G network, comprising: means for receiving information from a fifth core network node in the 4G network indicating that the wireless terminal has capability to support disaster-related roaming services; means for transmitting the subscriber data to a fifth core network node. (Appendix 27) A wireless terminal, Memory and configured to access memory, and at least one processor configured to receive, from a wireless station, information related to a System Information Block (SIB) including at least one of information indicating that disaster roaming is available, information indicating that disaster roaming using both 4G and 5G services is available, and information indicating that disaster roaming may be accepted even if there is no subscriber data. (Appendix 28) 1. A method for a wireless terminal, comprising: 1. A method comprising: means for receiving, from a wireless station, information associated with a System Information Block (SIB) including at least one of information indicating that disaster roaming is available, information indicating that disaster roaming using both 4G and 5G services is available, and information indicating that disaster roaming may be accepted even if there is no subscriber data. (Appendix 29) A Unified Data Management (UDM) in a 5G System (5GS), Memory and configured to access memory, Sync your data with the backup UDM on your 5GS, or and a Unified Data Management (UDM) comprising: at least one processor configured to communicate with a backup Home Subscriber Server (HSS) for an Evolved Packet System (EPS). (Appendix 30) A Home Subscriber Server (HSS) in an Evolved Packet System (EPS), Memory and configured to access memory and synchronize data with a backup HSS for the EPS, or A Home Subscriber Server (HSS) comprising: at least one processor configured to communicate with a backup Unified Data Management (UDM) of a 5G System (5GS). (Appendix 31) A method for Unified Data Management (UDM) in a 5G System (5GS), comprising: A means to synchronize data with the backup UDM on the 5GS, or A method comprising: means for communicating with a backup Home Subscriber Server (HSS) for an Evolved Packet System (EPS). (Appendix 32) 1. A method for a Home Subscriber Server (HSS) in an Evolved Packet System (EPS), comprising: A means of synchronizing data with a backup HSS for the EPS, or A method including means for communicating with a backup Unified Data Management (UDM) for a 5G System (5GS). (Appendix 33) A user equipment (UE), Memory and configured to access memory, and at least one processor configured to store at least one of a backup Subscription Permanent Identifier (SUPI) for disaster roaming services via an Evolved Packet System (EPS) and a backup International Mobile Subscriber Identity (IMS). (Appendix 34) Unified Data Management (UDM), Memory and configured to access memory, and at least one processor configured to store at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services via an Evolved Packet System (EPS). (Appendix 35) A user equipment (UE), Memory and configured to access memory, and at least one processor configured to store at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services via a 5G System (5GS). (Appendix 36) a Home Subscriber Server (HSS), Memory and configured to access memory, A Home Subscriber Server (HSS) configured to store at least one of a backup Subscription Permanent Identifier (SUPI) for disaster roaming services via a 5G System (5GS), and a backup International Mobile Subscriber Identity (IMS). (Appendix 37) 1. A method for user equipment (UE), comprising: A method comprising: means for storing at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services over an Evolved Packet System (EPS). (Appendix 38) 1. A method for Unified Data Management (UDM), comprising: A method comprising: means for storing at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services over an Evolved Packet System (EPS). (Appendix 39) 1. A method for user equipment (UE), comprising: A method comprising: means for storing at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services via 5GS. (Appendix 40) 1. A method for a Home Subscriber Server (HSS), comprising: A method, comprising: means for storing at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) for disaster roaming services over a 5G System (5GS). (Appendix 41) A core network node in a 5G System (5GS), Memory and configured to access memory, receiving a backup wireless terminal ID support indication from the user equipment (UE); Send a backup wireless terminal ID support indication to the Unified Data Management (UDM) in the 5GS, Send a backup wireless terminal ID support indication to the UDM, receiving at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMSI) from the UDM; at least one processor configured to transmit at least one of a backup SUPI and a backup IMSI to a wireless terminal. (Appendix 42) A method for a core network node in a 5G System (5GS), comprising: means for receiving a backup wireless terminal ID support indication from a user equipment (UE); a means for transmitting a backup wireless terminal ID support indication to a Unified Data Management (UDM) in the 5GS; means for transmitting a backup wireless terminal ID support indication to the UDM; means for receiving at least one of a backup Subscription Permanent Identifier (SUPI) and a backup International Mobile Subscriber Identity (IMS) from the UDM; means for transmitting at least one of a backup SUPI and a backup IMSI to the wireless terminal. (Appendix 43) A core network node in an Evolved Packet System (EPS), Memory and configured to access memory, Receive a backup wireless terminal ID support indication from the ratio terminal; Sends a backup wireless terminal ID support indication to the Home Subscriber Server (HSS) in the EPS, receiving at least one of a backup Subscription Permanent Identifier (SUPI) and an International Mobile Subscriber Identity (IMSI) from the HSS; at least one processor configured to transmit at least one of a backup SUPI and a backup IMSI to a wireless terminal. (Appendix 44) 1. A method for a core network node in an Evolved Packet System (EPS), comprising: means for receiving a backup wireless terminal ID support indication from the ratio terminal; means for transmitting a backup wireless terminal ID support indication to a Home Subscriber Server (HSS) in the EPS; means for receiving at least one of a backup Subscription Permanent Identifier (SUPI) and an International Mobile Subscriber Identity (IMSI) from the HSS; means for transmitting at least one of a backup SUPI and a backup IMSI to the wireless terminal. (Appendix 45) a core network node in a roaming network, Memory and configured to access memory, receiving at least one of a backup wireless terminal ID support indication, a backup Subscription Permanent Identifier (SUPI), and a backup Subscription Concealed Identifier (SUCI) from the wireless terminal; Sending at least one of a backup wireless terminal ID support indication, a backup SUPI, and a backup SUCI to a backup Unified Data Management (UDM); Sending at least one of a backup wireless terminal ID support indication, a backup SUPI, and a backup SUCI to the backup UDM; and at least one processor configured to receive subscriber data for disaster roaming from a backup UDM. (Appendix 46) 1. A method for a core network node in a roaming network, comprising: means for receiving at least one of a backup wireless terminal ID support indication, a backup Subscription Permanent Identifier (SUPI), and a backup Subscription Concealed Identifier (SUCI) from the wireless terminal; means for transmitting at least one of a backup wireless terminal ID support indication, a backup SUPI, and a backup SUCI to a backup Unified Data Management (UDM); means for transmitting at least one of a backup wireless terminal ID support indication, a backup SUPI, and a backup SUCI to the backup UDM; and means for receiving subscriber data for disaster roaming from the backup UDM. (Appendix 47) a core network node in a roaming network, Memory and configured to access memory, receiving at least one of a backup wireless terminal ID, a support indication, and a backup International Mobile Subscriber Identity (IMSI) from the terminal; Sending a backup wireless terminal ID support indication and a backup IMSI to a backup Home Subscriber Server (HSS), Receives subscriber data for disaster roaming from the backup HSS; and at least one processor specifically configured to transmit a message to a wireless terminal (UE). (Appendix 48) 1. A method for a core network node in a roaming network, comprising: means for receiving at least one of a backup wireless terminal ID, a support indication, and a backup International Mobile Subscriber Identity (IMSI) from the terminal; means for transmitting a backup wireless terminal ID support indication and a backup IMSI to a backup Home Subscriber Server (HSS); means for receiving subscriber data for disaster roaming from a backup HSS; means for transmitting a message to the wireless terminal.

[0289] This application claims the benefit of priority from Indian Patent Application No. 202311002701 filed on January 13, 2023, the disclosure of which is incorporated herein by reference in its entirety. [Explanation of symbols]

[0290] 20 Data Network 201 IMS 3UE 31 Transceiver Circuit 32 Antenna 33 Control Unit 34 User Interface 35 USIM 36 memory 361 Operating Systems 362 Communication Control Module 3621 Transceiver Control Module 5 RAN nodes 51 Transceiver circuit 52 Antenna 53 Network Interface 54 Control Unit 55 memory 551 Operating Systems 552 Communication Control Module 5521 Transceiver Control Module 60RU 601 Transceiver Circuit 602 Antenna 603 Network Interface 604 Control Unit 605 memory 6051 Operating System 6052 Communication Control Module 60521 Transceiver Control Module 61 DU 611 Transceiver Circuit 612 Network Interface 613 Control Unit 614 memory 6141 Operating System 6142 Communication Control Module 61421 Transceiver Control Module 62 CU 621 Transceiver Circuit 622 network interface 623 Control Unit 624 memory 6241 Operating System 6242 Communication Control Module 62421 Transceiver Control Module 7 Core Network 70 AMF 701 Transceiver Circuit 702 network interface 703 Control Unit 704 memory 7041 Operating System 7042 Communication Control Module 70421 Transceiver Control Module 71 SMF 72 UPF 73 PCF 731 Transceiver Circuit 732 network interface 733 Control Unit 734 memory 7341 Operating System 7342 Communication Control Module 73421 Transceiver Control Module 74 AUSF 741 Transceiver Circuit 742 network interfaces 743 Control Unit 744 memory 7441 Operating System 7442 Communication Control Module 74421 Transceiver Control Module 75 UDM 751 Transceiver Circuit 752 network interfaces 753 Control Unit 754 memory 7541 Operating Systems 7542 Communication Control Module 75421 Transceiver Control Module 76 NSSF 761 Transceiver Circuit 762 network interfaces 763 Control Unit 764 memory 7641 Operating System 7642 Communication Control Module 76421 Transceiver Control Module

Claims

1. Memory and configured to access the memory; Sending a setup request message to a first core network node in the first network, the setup request message including information about a list of connected networks; receiving a setup response message from the first core network node, the setup response message including at least one of information about a list of roaming networks and information about a priority of the roaming networks; Detecting a failure in a connection between the first core network node or another core network node in the first network; at least one processor configured to transmit to a wireless terminal at least one of information related to a disaster condition of the first network, information about the first network, information about the list of roaming networks, and the information about a priority of the roaming networks; A radio station comprising:

2. At least one of the information related to the disaster state of the first network, the information about the first network, the list of roaming networks, and the information about the priority of the roaming networks is included in a System Information Block (SIB) message or a Radio Resource Control Release message. The radio station according to claim 1 .

3. Memory and configured to access the memory; receiving a setup request message from the wireless station, the setup request message including information about a list of connected networks; at least one processor configured to transmit to the wireless station a setup response message including at least one of information about a list of disaster roaming networks and information about a priority of the disaster roaming networks; a first core network node in a first network, comprising:

4. Memory and configured to access the memory; receiving from a wireless station at least one of information related to a disaster condition of the first network, information about the first network, information about a list of roaming networks, and the information about a priority of the roaming networks; at least one processor configured to send a registration request message to a second core network node in the roaming network, the registration request message including parameters used to initiate disaster roaming services; A wireless terminal comprising:

5. means for sending a setup request message to a first core network node in the first network, the setup request message including information about a list of connected networks; means for receiving, from the first core network node, a setup response message including at least one of information about a list of roaming networks and information about a priority of the roaming networks; means for detecting a failure of a connection between the first core network node or another core network node in the first network; means for transmitting at least one of information related to a disaster condition of the first network, information about the first network, information about the list of roaming networks, and information about a priority of the roaming networks to a wireless terminal; 12. A method for a radio station, comprising:

6. the at least one of the information related to the disaster state of the first network, the information about the first network, the list of roaming networks, and the information about the priority of the roaming PLMN is included in a System Information Block (SIB) message or a Radio Resource Control Release message; The method of claim 5.

7. means for receiving a setup request message from a wireless station, the setup request message including information about a list of connected networks; means for transmitting a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about the priority of the disaster roaming networks; 2. A method for a first core network node in a first network, comprising:

8. means for receiving from a wireless station at least one of information related to a disaster condition of the first network, information about the first network, information about a list of roaming networks, and information about a priority of the roaming networks; means for sending a registration request message to a second core network node in the roaming network, the registration request message including parameters used to initiate disaster roaming services; A method for a wireless terminal, comprising:

9. Memory and configured to access the memory; receiving a setup request message from the wireless station, the setup request message including information about a list of connected networks; transmitting a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about a priority of the disaster roaming networks; receiving information from a second core network node in the first network indicating a need for minimizing service interruption; at least one processor configured to transmit information to the wireless station, the information including at least one of a new cause parameter, a disaster status indication parameter, and an available service parameter; a first core network node in a first network, comprising:

10. means for receiving a setup request message from a wireless station, the setup request message including information about a list of connected networks; means for transmitting a setup response message to the wireless station, the setup response message including at least one of information about a list of disaster roaming networks and information about priorities of the disaster roaming networks; means for receiving information from a second core network node in the first network indicating a need for minimizing service interruption; means for transmitting information to said wireless station, said information including at least one of a new cause parameter, a disaster status indication parameter, and an available service parameter; 2. A method for a first core network node in a first network, comprising:

11. Memory and configured to access the memory; Decided to provide disaster-related roaming services, transmitting a Radio Resource Control (RRC) Setup Request message to a wireless station, the message including information indicating that the wireless terminal has the capability to support the roaming service related to the disaster; receiving from the wireless station at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; transmitting an RRC Setup Complete message to the wireless terminal, the RRC Setup Complete message including at least one of information about the first network, the information indicating that the wireless terminal has the capability to support the disaster-related roaming service, and the information related to a disaster state of the first network; transmitting information related to the roaming network to the wireless station; at least one processor configured to transmit to the wireless terminal Non Access Stratum (NAS) container information including registration request information including at least one of the information indicating that the wireless terminal has the capability to support the disaster-related roaming service and the information related to a disaster condition of the first network; A wireless terminal comprising:

12. Memory and configured to access the memory; receiving a Radio Resource Control (RRC) Setup Request message from a wireless terminal, the message including information indicating the wireless terminal has capability to support disaster-related roaming services; transmitting to the wireless terminal at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; receiving an RRC setup complete message from the wireless terminal, the message including at least one of information about the first network, the information indicating that the wireless terminal has the capability to support the disaster-related roaming service, and the information related to a disaster state of the first network; receiving information related to the roaming network from the wireless terminal; receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; at least one processor configured to transmit a registration request message to a third core network node in the roaming network (PLMN2), the registration request message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; A radio station comprising:

13. Memory and configured to access the memory; receiving a message from a third core network node in a roaming network, the message including at least one of information indicating that the wireless terminal has capability to support the disaster-related roaming service and information related to a disaster condition of the first network; receiving a message from the third core network node, the message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; at least one processor configured to send a message including subscriber data to the third core network node; a fourth core network node in a disaster-related first network (PLMN1), comprising:

14. Memory and configured to access the memory; receiving a registration request message from the wireless station, the registration request message including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to a disaster condition of the first network; transmitting a message to a fourth core network node in a first network associated with the disaster, the message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service associated with the disaster and the information associated with a disaster state of the first network; transmitting a message to a fourth core network node, the message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; at least one processor configured to receive a message including subscriber data from the fourth core network node; a third core network node in the second network, comprising:

15. A means for determining whether to provide disaster-related roaming services; means for transmitting a Radio Resource Control (RRC) Setup Request message to a wireless station, the message including information indicating that the wireless terminal has the capability to support the roaming service related to the disaster; means for receiving from the wireless station at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; means for transmitting an RRC setup complete message to the wireless terminal, the message including at least one of information about the first network, the information indicating that the wireless terminal has the capability to support the disaster-related roaming service, and the information related to a disaster state of the first network; means for transmitting information related to the roaming network to the wireless station; means for transmitting Non Access Stratum (NAS) container information to the wireless station, the NAS container information including registration request information including at least one of the information indicating that the wireless terminal has the capability to support the disaster-related roaming service and the information related to a disaster state of the first network; A method for a wireless terminal, comprising:

16. means for receiving a Radio Resource Control (RRC) Setup Request message from a wireless terminal, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; means for transmitting to the wireless terminal at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; means for receiving an RRC setup complete message from the wireless terminal, the RRC setup complete message including at least one of information about the first network, the information indicating that the wireless terminal has the capability to support the disaster-related roaming service, and the information related to a disaster state of the first network; means for receiving information related to the roaming network from the wireless terminal; means for receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster condition for the first network; means for transmitting a registration request message to a third core network node in the roaming network, the registration request message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; 12. A method for a radio station, comprising:

17. means for receiving, from a third core network node in a roaming network, a message including at least one of information indicating that the wireless terminal has a capability to support the disaster-related roaming service and information related to a disaster state of the first network; means for receiving from the third core network node a message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; means for transmitting a message including subscriber data to said third core network node; a fourth core network node in a first network associated with a disaster, the fourth core network node comprising:

18. means for receiving, from the wireless terminal, a registration request message including at least one of information indicating that the wireless terminal has the capability to support disaster-related roaming services and information related to a disaster condition of the first network; means for transmitting a message to a fourth core network node in a first network associated with the disaster, the message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service associated with the disaster and the information associated with a disaster state of the first network; means for transmitting to the fourth core network node a message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; means for receiving a message including subscriber data from the fourth core network node; a third core network node in the second network, the third core network node receiving the first core network signal from the third core network node;

19. Memory and configured to access the memory; Decided to provide disaster-related roaming services, transmitting a Radio Resource Control (RRC) re-establishment request message to a wireless station, the message including information indicating that the wireless terminal has the capability to support the roaming service related to the disaster; receiving from the wireless station at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; transmitting an RRC Setup Complete message to the wireless terminal, the RRC Setup Complete message including at least one of information about the first network, the information indicating that the wireless terminal has the capability to support the disaster-related roaming service, and the information related to a disaster state of the first network; transmitting information related to the roaming network to the wireless station; at least one processor configured to transmit to the wireless terminal Non Access Stratum (NAS) container information including registration request information including at least one of the information indicating that the wireless terminal has the capability to support the disaster-related roaming service and the information related to a disaster condition of the first network; A wireless terminal comprising:

20. Memory and configured to access the memory; receiving a Radio Resource Control (RRC) re-establishment request message from the wireless terminal, the message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; transmitting to the wireless terminal at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; receiving an RRC setup complete message from the wireless terminal, the message including at least one of information about the first network, the information indicating that the wireless terminal has the capability to support the disaster-related roaming service, and the information related to a disaster state of the first network; receiving information related to the roaming network from the wireless terminal; receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; at least one processor configured to transmit a registration request message to a third core network node in the roaming network, the registration request message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; and A radio station comprising:

21. A means for determining whether to provide disaster-related roaming services; means for transmitting a Radio Resource Control (RRC) re-establishment request message to a wireless station, the message including information indicating that the wireless terminal has the capability to support the roaming service related to the disaster; means for receiving from the wireless station at least one of information related to a disaster state about first network information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; means for transmitting an RRC setup complete message to the wireless terminal, the message including at least one of information about the first network, the information indicating that the wireless terminal has the capability to support the disaster-related roaming service, and the information related to a disaster state of the first network; means for transmitting information related to the roaming network to the wireless station; means for transmitting Non Access Stratum (NAS) container information to the wireless station, the NAS container information including registration request information including at least one of the information indicating that the wireless terminal has the capability to support the disaster-related roaming service and the information related to a disaster state of the first network; A method for a wireless terminal, comprising:

22. means for receiving, from a wireless terminal, a Radio Resource Control (RRC) re-establishment request message including information indicating that the wireless terminal has the capability to support disaster-related roaming services; means for transmitting to the wireless terminal at least one of information related to a disaster state of a first network, information about the first network related to the disaster, information about a list of roaming networks, and information about a priority of the roaming networks; means for receiving an RRC setup complete message from the wireless terminal, the RRC setup complete message including at least one of information about the first network, the information indicating that the wireless terminal has the capability to support the disaster-related roaming service, and the information related to a disaster state of the first network; means for receiving information related to the roaming network from the wireless terminal; means for receiving Non Access Stratum (NAS) container information from the wireless terminal, the NAS container information including registration request information including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; means for transmitting a registration request message to a third core network node in the roaming network (PLMN2), the registration request message including at least one of the information indicating that the wireless terminal has the capability to support the roaming service related to the disaster and the information related to a disaster state of the first network; 12. A method for a radio station, comprising:

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