Disaster roaming

Abstract

One disclosure of the present specification provides a method. The method may comprise the steps of: transmitting a registration request message to a first network entity related to mobility; receiving, from the first network entity, a message related to registration rejection including a rejection reason; and selecting a PLMN for disaster roaming.

Description

Disaster Roaming

[0001] This specification relates to mobile communications.

[0002] 3GPP (3rd Generation Partnership Project) LTE (Long-Term Evolution) is a technology designed to enable high-speed packet communications. Numerous approaches have been proposed to achieve LTE's goals of reducing costs for users and operators, improving service quality, expanding coverage, and increasing system capacity. 3GPP LTE's high-level requirements include reduced cost per bit, improved service availability, flexible use of frequency bands, a simple architecture, open interfaces, and adequate power consumption for terminals.

[0003] The International Telecommunication Union (ITU) and 3GPP have begun work on developing requirements and specifications for New Radio (NR) systems. 3GPP must identify and develop the technical components necessary to successfully standardize NR, meeting both urgent market needs and the longer-term requirements outlined by the ITU Radio communication sector (ITU-R) International Mobile Telecommunications (IMT)-2020 process. NR must also be able to utilize any spectrum band up to at least 100 GHz, ensuring that it remains available for wireless communications well into the future.

[0004] NR aims to be a single technology framework that addresses all deployment scenarios, usage scenarios, and requirements, including enhanced Mobile Broadband (eMBB), massive Machine Type Communications (mMTC), and Ultra-Reliable and Low Latency Communications (URLLC). NR must be inherently forward-compatible.

[0005] In disaster situations, there is a need to support disaster roaming for terminals. However, conventional technology has the problem that terminals cannot effectively perform disaster roaming.

[0006] According to one embodiment of the present disclosure, a method is provided. The method may include: transmitting a registration request message to a first network entity associated with mobility; receiving a message related to a registration rejection including a reason for the rejection from the first network entity; and selecting a PLMN for disaster roaming.

[0007] According to one embodiment, a device implementing the method is provided.

[0008] According to one embodiment of the present disclosure, a method is provided. The method may include the steps of receiving a registration request message from a device; and transmitting a message related to a registration rejection, including a reason for the rejection, to the device.

[0009] According to one embodiment, a device implementing the method is provided.

[0010] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0011] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0012] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0013] Figure 4 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0014] Figures 5 and 6 illustrate examples of registration procedures to which the implementation of the present specification applies.

[0015] FIG. 7 is an example of a PLMN selection procedure and a registration procedure according to one embodiment of the disclosure of the present specification.

[0016] FIG. 8 is an example of a registration procedure according to one embodiment of the disclosure of the present specification.

[0017] FIG. 9 is an example of a UE configuration update procedure according to one embodiment of the disclosure of the present specification.

[0018] FIG. 10 is an example of a UE parameter update procedure according to one embodiment of the disclosure of the present specification.

[0019] FIG. 11 is an example of transmitting disaster-related system information according to one embodiment of the disclosure of the present specification.

[0020] FIG. 12 is an example of operations related to a PLMN selection procedure according to one embodiment of the disclosure of the present specification.

[0021] FIG. 13 is an example of a procedure related to registration acceptance according to one embodiment of the disclosure of the present specification.

[0022] FIG. 14 is an example of an operation related to registration rejection according to one embodiment of the disclosure of the present specification.

[0023] FIG. 15 illustrates an example of operations according to one embodiment of the disclosure of the present specification.

[0024] The following techniques, devices, and systems can be applied to various wireless multiple access systems. Examples of multiple access systems include Code Division Multiple Access (CDMA) systems, Frequency Division Multiple Access (FDMA) systems, Time Division Multiple Access (TDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Multi-Carrier Frequency Division Multiple Access (MC-FDMA) systems. CDMA can be implemented using wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented using wireless technologies such as Global System for Mobile communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data rates for GSM Evolution (EDGE). OFDMA can be implemented using wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (3rd Generation Partnership Project) Long-Term Evolution (LTE) is part of E-UMTS (Evolved UMTS) that utilizes E-UTRA.3GPP LTE uses OFDMA in the downlink (DL) and SC-FDMA in the uplink (UL). Evolution of 3GPP LTE includes LTE-A (Advanced), LTE-A Pro, and / or 5G NR (New Radio).

[0025] For convenience of explanation, the implementation of this specification is primarily described in relation to a 3GPP-based wireless communication system. However, the technical features of this specification are not limited thereto. For example, the following detailed description is provided based on a mobile communication system corresponding to a 3GPP-based wireless communication system, but aspects of this specification that are not limited to a 3GPP-based wireless communication system can be applied to other mobile communication systems.

[0026] For terms and technologies used in this specification that are not specifically described, reference may be made to wireless communication standard documents published prior to this specification.

[0027] As used herein, "A or B" can mean "only A," "only B," or "both A and B." Alternatively, as used herein, "A or B" can be interpreted as "A and / or B." For example, as used herein, "A, B or C" can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0028] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0029] In this specification, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in this specification, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted identically to “at least one of A and B.”

[0030] Additionally, in this specification, “at least one of A, B and C” can mean “only A”, “only B”, “only C”, or “any combination of A, B and C”. Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C”.

[0031] Additionally, parentheses used in this specification may mean "for example." Specifically, when indicated as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information." In other words, "control information" in this specification is not limited to "PDCCH," and "PDCCH" may be proposed as an example of "control information." Furthermore, even when indicated as "control information (e.g., PDCCH)", "PDCCH" may be proposed as an example of "control information."

[0032] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0033] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein may be applied to various fields requiring wireless communication and / or connectivity between devices (e.g., 5G).

[0034] Hereinafter, the present specification will be described in more detail with reference to the drawings. In the following drawings and / or description, the same reference numbers may refer to the same or corresponding hardware blocks, software blocks, and / or functional blocks, unless otherwise indicated.

[0035] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0036] The 5G usage scenario shown in FIG. 1 is only an example, and the technical features of this specification can be applied to other 5G usage scenarios not shown in FIG. 1.

[0037] The three main requirement categories for 5G are (1) enhanced mobile broadband (eMBB), (2) massive machine type communication (mMTC), and (3) ultra-reliable and low latency communications (URLLC).

[0038] Referring to FIG. 1, a communication system (1) includes wireless devices (100a to 100f), a base station (BS; 200), and a network (300). FIG. 1 illustrates a 5G network as an example of a network of the communication system (1), but the implementation of the present disclosure is not limited to a 5G system and can be applied to future communication systems beyond the 5G system.

[0039] The base station (200) and the network (300) may be implemented as wireless devices, and a particular wireless device may operate as a base station / network node in relation to other wireless devices.

[0040] The wireless devices (100a to 100f) represent devices that perform communication using Radio Access Technology (RAT) (e.g., 5G NR or LTE) and may also be referred to as communication / wireless / 5G devices. The wireless devices (100a to 100f) may include, but are not limited to, a robot (100a), a vehicle (100b-1 and 100b-2), an extended reality (XR) device (100c), a portable device (100d), a home appliance (100e), an Internet-of-Things (IoT) device (100f), and an artificial intelligence (AI) device / server (400). For example, the vehicles may include vehicles having wireless communication capabilities, autonomous vehicles, and vehicles capable of performing vehicle-to-vehicle communication. The vehicles may include unmanned aerial vehicles (UAVs) (e.g., drones). XR devices may include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and may be implemented in the form of HMD (Head-Mounted Device) and HUD (Head-Up Display) mounted on vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signs, vehicles, robots, etc. Portable devices may include smartphones, smart pads, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptops). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters.

[0041] In this specification, wireless devices (100a to 100f) may be referred to as user equipment (UE). The UE may include, for example, a mobile phone, a smartphone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate PC, a tablet PC, an ultrabook, a vehicle, a vehicle with autonomous driving function, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a fintech device (or a financial device), a security device, a weather / environmental device, a 5G service-related device, or a 4th industrial revolution-related device.

[0042] Wireless devices (100a to 100f) can be connected to a network (300) via a base station (200). AI technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) via the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a network after 5G. The wireless devices (100a to 100f) can communicate with each other via the base station (200) / network (300), but can also communicate directly (e.g., sidelink communication) without going through the base station (200) / network (300). For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). Additionally, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0043] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) and / or between wireless devices (100a to 100f) and a base station (200) and / or between base stations (200). Here, the wireless communication / connection can be established through various RATs (e.g., 5G NR), such as uplink / downlink communication (150a), sidelink communication (150b) (or, D2D (Device-To-Device) communication), and base station-to-base station communication (150c) (e.g., relay, IAB (Integrated Access and Backhaul)). Through the wireless communication / connection (150a, 150b, 150c), the wireless devices (100a to 100f) and the base station (200) can transmit / receive wireless signals to / from each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various proposals of this specification, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes can be performed.

[0044] NR supports multiple numerologies, or subcarrier spacings (SCS), to support diverse 5G services. For example, an SCS of 15 kHz supports wide areas in traditional cellular bands; an SCS of 30 kHz / 60 kHz supports dense urban areas, lower latency, and wider carrier bandwidth; and an SCS of 60 kHz or higher supports bandwidths greater than 24.25 GHz to overcome phase noise.

[0045] The NR frequency band can be defined by two types of frequency ranges (FR1 and FR2). The numerical values ​​of the frequency ranges can be changed. For example, the two types of frequency ranges (FR1 and FR2) can be as shown in Table 1 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 can mean the "sub 6 GHz range," and FR2 can mean the "above 6 GHz range," which can be called millimeter wave (mmW).

[0046] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0047] As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include a band from 410 MHz to 7125 MHz, as shown in Table 2 below. For example, FR1 may include a frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.). For example, the frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.) included within FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, such as for communications for vehicles (e.g., autonomous driving).

[0048] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0049] Here, the wireless communication technology implemented in the wireless device of the present specification may include not only LTE, NR, and 6G, but also Narrowband IoT (NB-IoT) for low-power communication. For example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present specification may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be called by various names such as eMTC (enhanced MTC). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (Non-Bandwidth Limited), 5) LTE-MTC, 6) LTE MTC, and / or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present specification can include at least one of ZigBee, Bluetooth, and / or LPWAN considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create PANs (Personal Area Networks) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0050] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0051] In FIG. 2, the first wireless device (100) and / or the second wireless device (200) may be implemented in various forms depending on the use case / service. For example, {the first wireless device (100) and the second wireless device (200)} may correspond to at least one of {the wireless devices (100a to 100f) and the base station (200)}, {the wireless devices (100a to 100f) and the wireless devices (100a to 100f)}, and / or {the base station (200) and the base station (200)} of FIG. 1. The first wireless device (100) and / or the second wireless device (200) may be configured by various components, devices / parts, and / or modules.

[0052] The first wireless device (100) may include at least one transceiver, such as a transceiver (106), at least one processing chip, such as a processing chip (101), and / or one or more antennas (108).

[0053] The processing chip (101) may include at least one processor, such as a processor (102), and at least one memory, such as a memory (104). Additionally and / or alternatively, the memory (104) may be located external to the processing chip (101).

[0054] The processor (102) may control the memory (104) and / or the transceiver (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. For example, the processor (102) may process information in the memory (104) to generate first information / signal and transmit a wireless signal including the first information / signal via the transceiver (106). The processor (102) may receive a wireless signal including second information / signal via the transceiver (106) and store information obtained by processing the second information / signal in the memory (104).

[0055] A memory (104) may be operatively connected to the processor (102). The memory (104) may store various types of information and / or instructions. The memory (104) may store firmware and / or software code (105) that implements code, instructions and / or sets of instructions that, when executed by the processor (102), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (105) may implement instructions that, when executed by the processor (102), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (105) may control the processor (102) to perform one or more protocols. For example, the firmware and / or software code (105) may control the processor (102) to perform one or more air interface protocol layers.

[0056] Here, the processor (102) and memory (104) may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). Each transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In the present specification, the first wireless device (100) may represent a communication modem / circuit / chip.

[0057] The second wireless device (200) may include at least one transceiver, such as a transceiver (206), at least one processing chip, such as a processing chip (201), and / or one or more antennas (208).

[0058] The processing chip (201) may include at least one processor, such as a processor (202), and at least one memory, such as a memory (204). Additionally and / or alternatively, the memory (204) may be located external to the processing chip (201).

[0059] The processor (202) may control the memory (204) and / or the transceiver (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein. For example, the processor (202) may process information in the memory (204) to generate third information / signal and transmit a wireless signal including the third information / signal via the transceiver (206). The processor (202) may receive a wireless signal including fourth information / signal via the transceiver (206) and store information obtained by processing the fourth information / signal in the memory (204).

[0060] A memory (204) may be operatively connected to the processor (202). The memory (204) may store various types of information and / or instructions. The memory (204) may store firmware and / or software code (205) that implements code, instructions and / or sets of instructions that, when executed by the processor (202), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (205) may implement instructions that, when executed by the processor (202), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (205) may control the processor (202) to perform one or more protocols. For example, the firmware and / or software code (205) may control the processor (202) to perform one or more air interface protocol layers.

[0061] Here, the processor (202) and memory (204) may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). A transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). Each transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with the RF unit. In the present specification, the second wireless device (200) may represent a communication modem / circuit / chip.

[0062] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as a physical (PHY) layer, a Media Access Control (MAC) layer, a Radio Link Control (RLC) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Resource Control (RRC) layer, and a Service Data Adaptation Protocol (SDAP) layer). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs), one or more Service Data Units (SDUs), messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0063] The one or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, and / or a microcomputer. The one or more processors (102, 202) may be implemented by hardware, firmware, software, and / or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), and / or one or more Field Programmable Gate Arrays (FPGAs) may be included in the one or more processors (102, 202). For example, the one or more processors (102, 202) may be configured by a set of a communication control processor, an Application Processor (AP), an Electronic Control Unit (ECU), a Central Processing Unit (CPU), a Graphic Processing Unit (GPU), and a Memory Control Processor. One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions and / or commands. The one or more memories (104, 204) may be configured as random access memory (RAM), dynamic RAM (DRAM), read-only memory (ROM), erasable programmable ROM (EPROM), flash memory, volatile memory, nonvolatile memory, hard drive, register, cache memory, computer readable storage media and / or combinations thereof.One or more memories (104, 204) may be located internally and / or externally to one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0064] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein from one or more other devices. For example, one or more transceivers (106, 206) can be coupled to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, wireless signals, etc., to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, wireless signals, etc. from one or more other devices.

[0065] One or more transceivers (106, 206) may be coupled to one or more antennas (108, 208). Additionally and / or alternatively, one or more transceivers (106, 206) may include one or more antennas (108, 208). One or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein via one or more antennas (108, 208). In the present disclosure, one or more antennas (108, 208) may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0066] One or more transceivers (106, 206) may convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202). One or more transceivers (106, 206) may convert processed user data, control information, wireless signals / channels, etc. from baseband signals to RF band signals using one or more processors (102, 202). For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or a filter. For example, one or more transceivers (106, 206) may up-convert an OFDM baseband signal to an OFDM signal via an (analog) oscillator and / or filter under the control of one or more processors (102, 202) and transmit the up-converted OFDM signal at a carrier frequency. One or more transceivers (106, 206) may receive an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal via an (analog) oscillator and / or filter under the control of one or more processors (102, 202).

[0067] Although not illustrated in FIG. 2, the wireless device (100, 200) may further include additional components. The additional components (140) may be configured in various ways depending on the type of the wireless device (100, 200). For example, the additional components (140) may include at least one of a power unit / battery, an input / output (I / O) device (e.g., an audio I / O port, a video I / O port), a driving device, and a computing device. The additional components (140) may be connected to one or more processors (102, 202) via various technologies, such as a wired or wireless connection.

[0068] In the implementation of this specification, a UE can operate as a transmitter in the uplink and as a receiver in the downlink. In the implementation of this specification, a base station can operate as a receiver in the UL and as a transmitter in the DL. For the sake of convenience of description, it is mainly assumed below that the first wireless device (100) operates as a UE and the second wireless device (200) operates as a base station. For example, a processor (102) connected to, mounted on, or released in the first wireless device (100) can be configured to perform UE operations according to the implementation of this specification or to control a transceiver (106) to perform UE operations according to the implementation of this specification. A processor (202) connected to, mounted on, or released in the second wireless device (200) can be configured to perform base station operations according to the implementation of this specification or to control a transceiver (206) to perform base station operations according to the implementation of this specification.

[0069] In this specification, a base station may be referred to as a Node B, an eNode B (eNB), or a gNB.

[0070] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0071] Referring to FIG. 3, the UE (100) can correspond to the first wireless device (100) of FIG. 2.

[0072] The UE (100) includes a processor (102), memory (104), a transceiver (106), one or more antennas (108), a power management module (141), a battery (142), a display (143), a keypad (144), a SIM (Subscriber Identification Module) card (145), a speaker (146), and a microphone (147).

[0073] The processor (102) may be configured to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts disclosed herein. The processor (102) may be configured to control one or more other components of the UE (100) to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts disclosed herein. A layer of a radio interface protocol may be implemented in the processor (102). The processor (102) may include an ASIC, other chipsets, logic circuits and / or data processing devices. The processor (102) may be an application processor. The processor (102) may include at least one of a DSP, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a modem (modulator and demodulator). An example of the processor (102) is the SNAPDRAGON manufactured by Qualcomm®. TM Series processors, EXYNOS made by Samsung® TM Series processors, A-series processors made by Apple®, HELIO made by MediaTek® TM ATOM series processors made by Intel® TM It can be found in the series processors or the corresponding next-generation processors.

[0074] Memory (104) is operatively coupled to the processor (102) and stores various information for operating the processor (102). Memory (104) may include ROM, RAM, flash memory, memory cards, storage media, and / or other storage devices. When the implementation is implemented in software, the techniques described herein may be implemented using modules (e.g., procedures, functions, etc.) that perform the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed herein. The modules may be stored in memory (104) and executed by the processor (102). Memory (104) may be implemented within the processor (102) or external to the processor (102), in which case it may be communicatively coupled to the processor (102) via various methods known in the art.

[0075] A transceiver (106) is operably coupled to the processor (102) and transmits and / or receives a radio signal. The transceiver (106) includes a transmitter and a receiver. The transceiver (106) may include a baseband circuit for processing a radio frequency signal. The transceiver (106) controls one or more antennas (108) to transmit and / or receive a radio signal.

[0076] The power management module (141) manages the power of the processor (102) and / or the transceiver (106). The battery (142) supplies power to the power management module (141).

[0077] The display (143) outputs the results processed by the processor (102). The keypad (144) receives input to be used by the processor (102). The keypad (144) can be displayed on the display (143).

[0078] A SIM card (145) is an integrated circuit that securely stores an International Mobile Subscriber Identity (IMSI) and associated keys, and is used to identify and authenticate subscribers in mobile devices such as mobile phones and computers. Additionally, many SIM cards can store contact information.

[0079] The speaker (146) outputs sound-related results processed by the processor (102). The microphone (147) receives sound-related input to be used by the processor (102).

[0080] Figure 4 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0081] The 5G system (5GS; 5G system) structure consists of the following network functions (NF; Network Function).

[0082] - AUSF (Authentication Server Function)

[0083] -AMF (Access and Mobility Management Function)

[0084] - DN (Data Network), for example, operator services, Internet access, or third-party services.

[0085] - USDF (Unstructured Data Storage Function)

[0086] - NEF (Network Exposure Function)

[0087] - I-NEF (Intermediate NEF)

[0088] - NRF (Network Repository Function)

[0089] - NSSF (Network Slice Selection Function)

[0090] - PCF (Policy Control Function)

[0091] - SMF (Session Management Function)

[0092] - UDM (Unified Data Management)

[0093] - UDR (Unified Data Repository)

[0094] - UPF (User Plane Function)

[0095] - UCMF (UE radio Capability Management Function)

[0096] - AF (Application Function)

[0097] - UE (User Equipment)

[0098] - (R)AN ((Radio) Access Network)

[0099] - 5G-EIR (5G-Equipment Identity Register)

[0100] - NWDAF (Network Data Analytics Function)

[0101] - CHF (CHarging Function)

[0102] 또한, 다음과 같은 네트워크 기능이 고려될 수 있다.

[0103] - N3IWF (Non-3GPP InterWorking Function)

[0104] - TNGF (Trusted Non-3GPP Gateway Function)

[0105] - W-AGF (Wireline Access Gateway Function)

[0106] Figure 4 illustrates the 5G system architecture for a non-roaming case using a reference point representation showing how various network functions interact with each other.

[0107] For clarity of the point-to-point diagram in Figure 4, UDSF, NEF, and NRF are not illustrated. However, all network functions shown can interact with UDSF, UDR, NEF, and NRF as needed.

[0108] For clarity, the connection between UDR and other NFs (e.g., PCF) is not shown in Fig. 4. For clarity, the connection between NWDAF and other NFs (e.g., PCF) is not shown in Fig. 4.

[0109] The 5G system architecture includes the following benchmarks:

[0110] - N1: Reference point between UE and AMF.

[0111] - N2: Reference point between (R)AN and AMF.

[0112] - N3: Reference point between (R)AN and UPF.

[0113] - N4: Reference point between SMF and UPF.

[0114] - N6: Reference point between UPF and data network.

[0115] - N9: Reference point between two UPFs.

[0116] The following benchmarks illustrate the interactions that exist between NF services in NF.

[0117] - N5: Reference point between PCF and AF.

[0118] - N7: Reference point between SMF and PCF.

[0119] - N8: Reference point between UDM and AMF.

[0120] - N10: Reference point between UDM and SMF.

[0121] - N11: Reference point between AMF and SMF.

[0122] - N12: Reference point between AMF and AUSF.

[0123] - N13: Reference point between UDM and AUSF.

[0124] - N14: Reference point between two AMFs.

[0125] - N15: Reference point between PCF and AMF for non-roaming scenarios, and reference point between PCF and AMF of visited network for roaming scenarios.

[0126] - N16: Reference point between two SMFs (in case of roaming, between the SMF of the visited network and the SMF of the home network)

[0127] - N22: Reference point between AMF and NSSF.

[0128] In some cases, two NFs may need to be interconnected to serve a UE.

[0129] Describes the registration procedure. See section 4.2.2.2 of 3GPP TS 23.502 V16.3.0 (2019-12).

[0130] Figures 5 and 6 illustrate examples of registration procedures to which the implementation of the present specification applies.

[0131] A UE must register with the network to receive services, enable mobility tracking, and enable reachability. The UE initiates the registration process using one of the following registration types:

[0132] - Initial registration for 5GS; or

[0133] - mobility registration update; or

[0134] - Periodic registration update; or

[0135] - Emergency registration

[0136] The general registration procedures of Figures 5 and 6 apply to all registration procedures described above, but periodic registration updates do not need to include all parameters used in other registration procedures.

[0137] The general registration procedures of Figures 5 and 6 can also be used to register a UE for a 3GPP connection when it is already registered for a non-3GPP connection, and vice versa. Registering a UE for a 3GPP connection when it is already registered for a non-3GPP connection scenario may require an AMF change.

[0138] First, the procedure of Fig. 5 is described.

[0139] (1) Step 1: The UE transmits a Registration Request message to the (R)AN. The Registration Request message corresponds to an AN message.

[0140] The registration request message may include AN parameters. For NG-RAN, the AN parameters include, for example, the 5G SAE temporary mobile subscriber identity (5G-S-TMSI) or globally unique AMF ID (GUAMI), the selected public land mobile network (PLMN) ID (or PLMN ID and network identifier (NID)), and the requested network slice selection assistance information (NSSAI). The AN parameters also include an establishment cause. The establishment cause provides the reason for requesting establishment of an RRC connection. Whether and how the UE includes the requested NSSAI as part of the AN parameters depends on the value of the access stratum connection establishment NSSAI inclusion mode parameter.

[0141] A registration request message may include a registration type. The registration type indicates whether the UE wants to perform an initial registration (e.g., the UE is in RM-DEREGISTERED state), or a mobility registration update (e.g., the UE is in RM-REGISTERED state and initiates a registration procedure because the UE moves, or the UE wants to update capabilities or protocol parameters, or requests a change in the set of network slices the UE is allowed to use), or a periodic registration update (e.g., the UE is in RM-REGISTERED state and initiates a registration procedure because a periodic registration update timer expires), or an emergency registration (e.g., the UE is in a restricted service state).

[0142] When a UE performs initial registration, the UE indicates its UE ID in the registration request message, listed in decreasing priority order.

[0143] i) If the UE has a valid evolved packet system (EPS) globally unique temporary identifier (GUTI), 5G-GUTI mapped from the EPS GUTI;

[0144] ii) Native 5G-GUTI (if available) allocated by the PLMN in which the UE is attempting to register;

[0145] iii) Native 5G-GUTI allocated by a PLMN equivalent to the PLMN in which the UE is attempting to register;

[0146] iv) Native 5G-GUTI allocated by another PLMN (if available);

[0147] v) Otherwise, the UE includes a subscriber concealed identifier (SUCI) in the registration request message.

[0148] If a UE performing initial registration has both a valid EPS GUTI and a native 5G-GUTI, the UE also indicates the native 5G-GUTI as an additional GUTI. If more than one native 5G-GUTI is available, the UE selects a 5G-GUTI from items (ii)-(iv) in decreasing priority order in the list above.

[0149] When the UE performs initial registration with native 5G-GUTI, the UE indicates the relevant GUAMI information in the AN parameters. When the UE performs initial registration with SUCI, the UE does not indicate the GUAMI information in the AN parameters.

[0150] For emergency registration, if the UE does not have a valid 5G-GUTI, the SUCI is included. If the UE does not have a subscriber permanent identifier (SUPI) and does not have a valid 5G-GUTI, the PEI (Permanent Equipment Identifier) ​​is included. Otherwise, the 5G-GUTI is included, indicating the last serving AMF.

[0151] The registration request message may also include security parameters, PDU session status, etc. Security parameters are used for authentication and integrity protection. The PDU session status indicates a previously established PDU session in the UE. When the UE is connected to two AMFs belonging to different PLMNs via a 3GPP connection and a non-3GPP connection, the PDU session status indicates the PDU session currently established in the PLMN in the UE.

[0152] (2) Step 2: (R)AN selects AMF.

[0153] If 5G-S-TMSI or GUAMI is not included, or if 5G-S-TMSI or GUAMI does not indicate a valid AMF, the (R)AN selects an AMF based on the (R)AT and the requested NSSAI, if available.

[0154] When the UE is in CM-CONNECTED state, (R)AN can forward a registration request message to AMF based on the N2 connection of the UE.

[0155] If the (R)AN cannot select an appropriate AMF, the (R)AN performs AMF selection by forwarding a registration request message to the AMF configured in the (R)AN.

[0156] (3) Step 3: (R)AN sends a registration request message to the new AMF. The registration request message corresponds to the N2 message.

[0157] The registration request message may contain all of the information and / or part of the information contained in the registration request message received from the UE described in step 1.

[0158] The registration request message may include an N2 parameter. When NG-RAN is used, the N2 parameter includes the selected PLMN ID (or PLMN ID and NID), location information and cell ID related to the cell where the UE is camping, and a UE context request indicating that a UE context including security information should be established in the NG-RAN. When NG-RAN is used, the N2 parameter also includes an establishment cause.

[0159] If the registration type indicated by the UE is periodic registration update, steps 4-19 described below may be omitted.

[0160] (4) Step 4: If the UE's 5G-GUTI is included in the registration request message and the serving AMF has changed since the last registration procedure, the new AMF may invoke the Namf_Communication_UEContextTransfer service operation to the previous AMF, including the full registration request non-access stratum (NAS) message to request the UE's SUPI and UE context.

[0161] (5) Step 5: The old AMF can respond to the new AMF for the Namf_Communication_UEContextTransfer call including the UE's SUPI and UE context.

[0162] (6) Step 6: If SUCI is not provided by the UE or not retrieved from the previous AMF, the new AMF may initiate an ID request procedure by sending an Identity Request message to request SUCI from the UE.

[0163] (7) Step 7: The UE may respond with an Identity Response message including the SUCI. The UE derives the SUCI using the provided public key of the home PLMN (HPLMN).

[0164] (8) Step 8: The new AMF may decide to initiate UE authentication by calling the AUSF. In this case, the new AMF selects the AUSF based on SUPI or SUCI.

[0165] (9) Step 9: Authentication / security can be established by UE, new AMF, AUSF and / or UDM.

[0166] (10) Step 10: If the AMF has changed, the new AMF may call the Namf_Communication_RegistrationCompleteNotify service operation to notify the old AMF that the UE registration with the new AMF is complete. If the authentication / security procedure fails, the registration is rejected and the new AMF may call the Namf_Communication_RegistrationCompleteNotify service operation with a reject indication reason code to the old AMF. The old AMF may continue as if the UE context transfer service operation was not received.

[0167] (11) Step 11: If the PEI was not provided by the UE or was not retrieved from the previous AMF, the new AMF may initiate the ID request procedure by sending an Identity Request message to the UE to retrieve the PEI. The PEI is transmitted encrypted, except when the UE performs emergency registration and cannot be authenticated.

[0168] (12) Step 12: Optionally, the new AMF can initiate ME ID checking by calling the N5g-eir_EquipmentIdentityCheck_Get service operation.

[0169] Now, the procedure of Fig. 6 following the procedure of Fig. 5 is described.

[0170] (13) Step 13: When step 14 below is performed, the new AMF can select a UDM based on SUPI, and the UDM can select a UDR instance.

[0171] (14) Step 14: New AMFs can be registered with UDM.

[0172] (15) Step 15: New AMF can select PCF.

[0173] (16) Step 16: The new AMF may optionally perform AM policy association establishment / modification.

[0174] (17) Step 17: The new AMF can send update / release SM context messages (e.g., Nsmf_PDUSession_UpdateSMContext and / or Nsmf_PDUSession_ReleaseSMContext) to the SMF.

[0175] (18) Step 18: If the new AMF and the old AMF are in the same PLMN, the new AMF may send a UE context modification request to the N3IWF / TNGF / W-AGF.

[0176] (19) Step 19: N3IWF / TNGF / W-AGF may send a UE context modification response to the new AMF.

[0177] (20) Step 20: After the new AMF receives the response message from N3IWF / TNGF / W-AGF in step 19, the new AMF can register with UDM.

[0178] (21) Step 21: The new AMF sends a Registration Accept message to the UE.

[0179] The new AMF sends the UE a Registration Accept message indicating that the registration request has been accepted. If the new AMF allocates a new 5G-GUTI, it includes the 5G-GUTI. If the UE is already in the RM-REGISTERED state through another connection to the same PLMN, the UE uses the 5G-GUTI received in the Registration Accept message for both registrations. If the Registration Accept message does not include a 5G-GUTI, the UE uses the 5G-GUTI assigned to the existing registration for the new registration. If the new AMF allocates a new registration area, it sends the registration area to the UE in the Registration Accept message. If the Registration Accept message does not include a registration area, the UE considers the previous registration area to be valid. Mobility Restrictions are included if mobility restrictions apply to the UE and the registration type is not emergency registration. The new AMF indicates the PDU sessions established for the UE in the PDU Session State. The UE locally removes internal resources associated with PDU sessions that are not marked as established in the received PDU Session State. When a UE is connected to two AMFs belonging to different PLMNs via a 3GPP connection and a non-3GPP connection, the UE locally removes internal resources associated with PDU sessions in the current PLMN that are not marked as established in the received PDU session status. If PDU session status information is present in the Registration Accept message, the new AMF indicates the PDU session status to the UE.

[0180] The Allowed NSSAI provided in the Registration Accept message is valid for the registration area and applies to all PLMNs that have a tracking area included in the registration area. The Mapping of Allowed NSSAIs maps HPLMN S-NSSAIs to each S-NSSAI of the Allowed NSSAIs. The Mapping of Configured NSSAIs maps HPLMN S-NSSAIs to each S-NSSAI of the Configured NSSAI for the serving PLMN.

[0181] Additionally, optionally, the new AMF performs UE policy association establishment.

[0182] (22) Step 22: If the UE successfully updates itself, it can send a Registration Complete message to the new AMF.

[0183] The UE may send a registration complete message to the new AMF to confirm that a new 5G-GUTI has been allocated.

[0184] (23) Step 23: In case of registration via 3GPP connection, if the new AMF does not release the signaling connection, the new AMF may send RRC Inactive Assistance information to the NG-RAN. In case of registration via non-3GPP connection, if the UE is in CM-CONTENED state on the 3GPP connection, the new AMF may send RRC Inactive Assistance information to the NG-RAN.

[0185] (24) Step 24: AMF can perform information updates on UDM.

[0186] (25) Step 25: The UE may execute a network slice-specific authentication and authorization (NSSAA) procedure.

[0187] A network disaster may prevent UEs from accessing their subscribed network. In such cases, the Minimization of Service Interruption (MINT) feature, which allows UEs to access services through networks other than their original network, is being discussed.

[0188] For example, TS24.501 0 S4.24 can be referenced for MINT.

[0189] For example, the UE and the network may support Minimization of Service Interruption (MINT). MINT aims to ensure that the UE can receive service from the PLMN providing disaster roaming services when disaster conditions apply to the PLMN determined by the UE based on the disaster conditions.

[0190] If the UE supports MINT, an indication of whether disaster roaming is enabled in the UE, an indication of the applicability of the 'lists of PLMN(s) to be used in disaster condition' provided by the VPLMN, one or more 'lists of PLMN(s) to be used in disaster condition', a disaster roaming wait range provided by the network and a disaster return wait range (if available) are stored in non-volatile memory of the ME and may be maintained when the UE enters the 5GMM-DEREGISTERED state.

[0191] When a UE selects a PLMN for disaster roaming as specified in 3GPP TS 23.122 V18.6.0, the following applies:

[0192] a) If there is no disaster roaming standby range stored in the UE, the UE may perform a disaster roaming service registration procedure for the selected PLMN; and

[0193] b) If the UE has a disaster roaming standby range stored, the UE may generate a random number within the disaster roaming standby range and start a timer with the generated random number. While the timer is running, the UE shall not initiate registration for the selected PLMN, except when it needs to request an emergency PDU session, in which case the UE initiates a registration procedure and sets the 5GS Registration Type IE in the Registration Request message to "Emergency Registration" and continues the timer. If the UE does not have an emergency PDU session when the timer expires, the UE performs a registration procedure for the disaster roaming service if it is still camped on the selected PLMN. If the UE has an emergency PDU session when the timer expires, the UE performs a disaster roaming service registration procedure after the emergency PDU session is released if it is still camped on the selected PLMN.

[0194] When a timer started with a random number generated within the disaster roaming standby range is stopped and the following conditions are met, the UE can perform PLMN selection as described in 3GPP TS 23.122:

[0195] a) If the UE has successfully registered via non-3GPP access in another PLMN;

[0196] b) if the UE has successfully registered with an acceptable PLMN; or

[0197] c) If the NG-RAN cell selected for camping on the selected PLMN does not broadcast a "List of one or more PLMNs with disaster conditions providing disaster roaming services" containing the determined PLMNs with disaster-related indications or disaster conditions.

[0198] TS23.122 v18.6.0 S3.10 Minimization of service interruption may also be referenced.

[0199] A UE may include a Mobile Station (MS) and Mobile Equipment (ME). The MS may support MINT. In various examples disclosed herein, operations performed by the MS may be performed by the UE.

[0200] For a PLMN providing disaster roaming service, if one of the CAG-IDs broadcasted by the CAG cell for the PLMN is approved according to the "Allowed CAG List" included in the PLMN entry of the "CAG Information List", the UE may attempt to access the PLMN of the CAG cell for disaster roaming service.

[0201] If the MS supports MINT, the network can provide the MS with:

[0202] a) HPLMN may provide an indication to the UE whether disaster roaming is enabled on the UE;

[0203] b) HPLMN may provide a "list of PLMN(s) to be used in disaster conditions." The "list of PLMN(s) to be used in disaster conditions" may consist of zero or more items, each of which may contain a PLMN ID. PLMNs are listed in decreasing order of priority, with the first PLMN having the highest priority;

[0204] c) One or more "list of PLMN(s) to be used in disaster conditions" may be provided. Each VPLMN may provide the UE with one "list of PLMN(s) to be used in disaster conditions". The "list of PLMN(s) to be used in disaster conditions" may contain zero or more entities, each of which may contain a PLMN ID. The PLMNs are listed in decreasing order of priority, with the first PLMN being the highest priority PLMN;

[0205] d) Disaster roaming standby range consisting of minimum and maximum standby times;

[0206] e) Disaster recovery standby range consisting of minimum and maximum standby times; and

[0207] f) Indication of the applicability of the “List of PLMNs available in disaster situations” provided by the VPLMN may be provided by the HPLMN.

[0208] The network may provide the UE with the "PLMN list to be used in disaster situations", the disaster roaming standby range, and the disaster reversion standby range during a successful registration procedure or a generic UE configuration update procedure. The network may also provide the UE with the disaster reversion standby range during a network-initiated deregistration procedure, a failed registration procedure, or a failed service request procedure. Additionally, the HPLMN may provide an indication of whether disaster roaming is enabled in the UE and the applicability of the "PLMN list to be used in disaster situations" provided by the VPLMN during a UE parameter update procedure.

[0209] An indication of whether disaster roaming is enabled in the UE, an indication of the applicability of the “PLMN list to be used in disaster situations” provided by the VPLMN, one or more instances of the “PLMN list to be used in disaster situations” and the PLMN identity of the PLMN providing the instance, the disaster roaming standby range provided by the network and the disaster return standby range are stored in the non-volatile memory of the ME.

[0210] Additionally, an indication of whether disaster roaming is activated in the UE, an indication of the applicability of the 'PLMN list to be used in a disaster situation' provided by the VPLMN, a 'PLMN list to be used in a disaster situation' provided by the HPLMN, a disaster roaming standby range, and a disaster return standby range stored in the USIM can be preset in the MS.

[0211] For reference, TS23.122 v18.6.0 S4.3.3.1.1 Automatic Network Selection Mode Procedure may also be referenced. An example based on TS23.122 v18.6.0 S4.3.3.1.1 is described below. For any portion not described below, TS23.122 v18.6.0 S4.3.3.1.1 may be referenced.

[0212] For example, a terminal may attempt to connect by selecting a different PLMN / access technology combination with the following priorities:

[0213] i) MS attempts to register with the HPLMN (if the EHPLMN list is missing or empty) or with the highest priority EHPLMN available (if the EHPLMN list is present);

[0214] ii) The MS attempts to register for each PLMN / Access Technology combination (in order of priority) present in the SIM's "User Controlled PLMN Selector with Access Technology" data file;

[0215] iii) For each PLMN / Access Technology combination contained (in order of priority) in the "Operator Controlled PLMN Selector with Access Technology" data file of the SIM or stored (in order of priority) in the ME, the MS attempts registration for each PLMN / Access Technology combination;

[0216] iv) For high quality signals received in any order and for other PLMN / access technology combinations, the MS attempts registration;

[0217] v) For other PLMN / access technology combinations in descending order of signal quality, the MS attempts registration.

[0218] vi) A forbidden PLMN may broadcast the PLMN ID of a UE-determined PLMN with disaster conditions or broadcast disaster-related indications. If the PLMN / NG-RAN combination for such a forbidden PLMN satisfies the following conditions, the MS may attempt to register with the PLMN / NG-RAN combination that satisfies the following conditions:

[0219] a) If 'Applicability of PLMN list to be used in disaster situations provided by VPLMN' is set to true, the following explanation may apply:

[0220] - Within the "PLMN List to be used in disaster conditions" stored in the ME, for each PLMN associated with the PLMN ID of the PLMN (if any) determined by the MS based on the disaster conditions, the MS may attempt registration based on the order of the PLMN list; otherwise

[0221] - In the "PLMN list to be used in disaster conditions" stored in the ME, there may not be a PLMN associated with the PLMN ID of the PLMN (if any) determined by the MS based on disaster conditions. In this case, if there is a PLMN ID associated with the PLMN of the HPLMN in the "PLMN list to be used in disaster conditions" stored in the ME, the MS may attempt registration based on the order of the PLMN list.

[0222] b) If the indication of 'Applicability of PLMN list for use in disaster situations' provided by VPLMN is set to false:

[0223] - For each PLMN associated with the HPLMN, within the "PLMN list to be used in disaster conditions" stored in the ME, the MS may attempt registration.

[0224] vii) For PLMN / NG-RAN combinations that broadcast the PLMN ID of a MS-determined PLMN with disaster condition or other prohibited PLMNs that broadcast disaster-related indications, the MS may attempt registration in any order.

[0225] At this time, if the PLMN is a PLMN that is not permitted as a forbidden PLMN, the terminal can select a PLMN in the order of vi) and v) and perform a connection attempt.

[0226] According to vi) and v), the terminal can select a PLMN selected in a disaster situation by NG-RAN, and the terminal can perform PLMN selection using the PLMN selected in the disaster condition.

[0227] When performing PLMN selection, if the terminal satisfies certain requirements, it can select a PLMN based on the requirements. In a disaster situation, if requirements q1) and q2) are satisfied, the terminal can perform the above PLMN selection based on vi) and v).

[0228] q1) For vi and vii, if the prohibited PLMN broadcasts "list of one or more PLMN(s) with disaster condition for which disaster roaming services is offered by the available PLMN", the MS determines the MS-determined PLMN with disaster condition as follows:

[0229] i) If the MS's RPLMN is included in and allowed by the "List of PLMNs with one or more disaster conditions for which disaster roaming service is provided by available PLMNs" broadcast by the NG-RAN cell, the MS may consider the RPLMN as a PLMN determined by the MS based on the disaster conditions; or

[0230] ii) If the MS's RPLMN is not included in the "List of PLMNs with one or more disaster conditions for which disaster roaming service is provided by available PLMNs" broadcast by the NG-RAN cell, or the MS's RPLMN is not allowed, or the MS does not have an RPLMN, the MS may determine the PLMN determined by the MS based on the disaster condition from the PLMNs based on the following conditions:

[0231] - a PLMN included in the "List of PLMNs with one or more disaster conditions for which disaster roaming services are provided by available PLMNs" broadcast by any NG-RAN cell; and

[0232] - If it is an acceptable PLMN;

[0233] The MS can determine the PLMN based on the disaster conditions in the following order:

[0234] - (if the EHPLMN list is missing or empty) or the highest priority EHPLMN available (if the EHPLMN list is present);

[0235] - Each PLMN (in order of priority) in the SIM's "User Controlled PLMN Selector with Access Technology" data file;

[0236] - each PLMN (priority) present in the SIM's "Operator Controlled PLMN Selector with Access Technology" data file (priority) or stored in the ME; and

[0237] - Other PLMNs.

[0238] q2) For vi and vii, if the prohibited PLMN broadcasts a "disaster related indication", the MS may determine the PLMN that the MS has determined based on the disaster condition as follows:

[0239] 1) If the RPLMN country of the MS matches the country of the PLMN where the NG-RAN cell broadcasts the "disaster related indication" and the RPLMN of the MS is allowed, the MS considers the PLMN as determined by the MS based on the disaster conditions; or

[0240] 2) If the country of the RPLMN of the MS does not match the country of the PLMN from which the NG-RAN cell broadcasts the "disaster related indication" or the RPLMN of the MS is not allowed, the MS may determine the PLMN from among the allowable PLMNs from which the country of the allowable PLMN matches the country of the PLMN from which the NG-RAN cell broadcasts the "disaster related indication", based on the following order:

[0241] - (if the EHPLMN list is missing or empty) or the highest priority EHPLMN available (if the EHPLMN list is present);

[0242] - Each PLMN (in order of priority) in the SIM's "User Controlled PLMN Selector Based on Access Technology" data file;

[0243] - Each PLMN (priority) present in the SIM's "Operator Controlled PLMN Selector Based on Access Technology" data file (priority) or stored in the ME.

[0244] For example, q1) described above may be a requirement when NG-RAN transmits a list of PLMNs available under disaster conditions for disaster roaming services, and q2) may be a requirement when NG-RAN notifies disaster-related indicators for disaster roaming services.

[0245] If the requirements of q1) or q2) above are satisfied, PLMN selection is performed in the order of vi) and vii).

[0246] For example, as described in vi), for any forbidden PLMN that broadcasts the PLMN ID of the PLMN determined in disaster condition by NG-RAN to the forbidden PLMN or broadcasts disaster related indicators, if the indication of use of the PLMN list used in disaster situation provided by the VPLMN can be TRUE. In this case, based on the PLMN List in disaster state associated with the PLMN ID of the PLMN determined in disaster condition, the MS selects the PLMN in priority order. If the indication of use of the PLMN list used in disaster situation provided by the VPLMN is FALSE, the MS selects the PLMN in priority order based on the PLMN list used in disaster state associated with the HPLMN.

[0247] For example, as described in vii), the MS selects the PLMN in random order.

[0248] Below is an example of Automatic Network Selection.

[0249] For example, when an SKT subscriber's terminal moves to Japan, assuming that SKT has a roaming contract with NTT docomo, the terminal's HPLMN is SKT and VPLMN is NTT docomo.

[0250] If the terminal is located in Japan, disasters may occur frequently in certain areas of Japan. In this case, the government may request NTT Docomo to configure the terminal in Japan to notify the VPLMN that can be used during disasters. In this case, when the terminal establishes a connection to NTT Docomo, the VPLMN can provide a list of PLMNs available during disasters. For example, the PLMNs announced via the VPLMN could be those of SoftBank, KDDI, or another operator in the region.

[0251] If a specific core network becomes unavailable due to a subsequent disaster, the NG-RAN of a PLMN capable of disaster roaming can broadcast information about its own NG-RAN cell that indicates that disaster roaming is possible. The information broadcast by the NG-RAN can be, for example, a disaster-related indicator provided by the NG-RAN or a list of PLMNs in a disaster state.

[0252] When a terminal is in a disaster state, even if a specific NG-RAN is used for disaster roaming, a connection can be established using a PLMN that supports disaster roaming connected to the NG-RAN. Therefore, if a specific NG-RAN can only establish a connection with a specific PLMN, the NG-RAN can notify the list. Even if the NG-RAN notifies the list of available PLMNs related to disaster roaming, the terminal can establish a connection to a PLMN where a connection is established by the AMF via the HPLMN. The terminal selects a PLMN based on the disaster information by the NG-RAN and the disaster information by the AMF.

[0253] For reference, the definitions of terms used in various examples of the disclosure of this specification are as follows.

[0254] Access Technology: The Access Technology is the access technology associated with a PLMN or SNPN. The MS can use this information to determine which wireless carrier type to search when selecting a specific PLMN or SNPN.

[0255] Allowable PLMN: For an MS operating in MS Operation Mode A or B, this means a PLMN that is not on the MS's "Forbidden PLMN" list. For an MS operating in MS Operation Mode C, or an MS that does not support A / Gb mode and does not support Iu mode, an Allowable PLMN may be a PLMN that is not on the MS's "Forbidden PLMN" list and also not on the "Forbidden PLMN for GPRS Service" list.

[0256] Home PLMN: The PLMN where the MCC and MNC of the PLMN ID may match the MCC and MNC of the UE's IMSI.

[0257] SIM: Subscriber Identity Module. In this specification, there is no distinction between SIM and USIM.

[0258] EHPLMN: All PLMN entries included in the Equivalent HPLMN list.

[0259] Equivalent HPLMN List: To allow for the provision of multiple HPLMN codes, the PLMN codes in this list replace the HPLMN code derived from the IMSI for PLMN selection purposes. This list is stored in the USIM and is known as the Equivalent HPLMN List. The Equivalent HPLMN List may also include HPLMN codes derived from the IMSI. If the HPLMN code derived from the IMSI is not in the Equivalent HPLMN List, the HPLMN code derived from the IMSI is considered the visited PLMN for PLMN selection purposes.

[0260] UE-determined PLMN with disaster condition: A PLMN to which disaster conditions apply. For disaster conditions, refer to TS23.122 v18.6.0 S4.4.3.1.1.

[0261] Available PLMN: One or more PLMNs for which the UE has discovered at least one cell and read its PLMN ID.

[0262] In various examples of the disclosure of this specification, the following description may apply to disaster conditions. The 3GPP system enables a UE to obtain information that a disaster condition applies to a specific PLMN. The 3GPP system supports a means for a PLMN operator to recognize the area where the disaster condition applies. Service provision to a disaster inbound roamer may be supported only within the specific area where the disaster condition applies. The network may notify a disaster inbound roamer that the disaster condition no longer applies. Depending on regulatory requirements or operator policies, the 3GPP system may support a PLMN operator to recognize the failure or recovery of another PLMN in the same country when a disaster condition applies or when a disaster condition does not apply.

[0263] In various examples of the disclosure of this specification, the following description may apply to disaster roaming.

[0264] 3GPP system shall be able to collect charging information for a Disaster Inbound Roamer with information about the applied disaster condition.

[0265] When a disaster condition applies and no other PLMN is available except for a PLMN in the prohibited PLMN list, the UE may access a PLMN in the prohibited PLMN list. Disaster conditions may apply to UEs in a specific PLMN. 3GPP systems can provide a resource-efficient means to indicate to potential disaster inbound roamers whether they can access that PLMN. Disaster inbound roamers perform network reselection when the disaster situation ends. 3GPP systems should minimize congestion due to disaster roaming. 5G systems and EPS can support a mechanism for the HPLMN to control whether UEs with HPLMN subscriptions should apply disaster roaming (either in the HPLMN or in a VPLMN) during a disaster situation. 3GPP systems can collect charging information for disaster inbound roamers along with information about the applied disaster conditions.

[0266] For these MINT features, the NW (e.g., NG-RAN and / or AMF) can transmit disaster-related information to the UE. For example, the NW can transmit a disaster roaming enable indicator to the UE. For example, the NW can transmit to the UE a list of PLMN(s) to be used in a disaster condition provided by the VPLMN, or a list of PLMN(s) to be used in a disaster condition provided by the HPLMN. For example, the NW can transmit to the UE a disaster roaming wait timer range to be used for congestion control in the PLMN to which the UE will connect in a disaster condition. For example, the NW can transmit to the UE disaster return wait timer information for congestion control of the PLMN to which the UE will return when the disaster condition ends and the UE returns to its original PLMN. Alternatively, one or more of the various examples described above may be pre-configured and stored in the UE.

[0267] When a disaster occurs, the NW (e.g., base station, AMF, etc.) can inform the UE which PLMN is available for selection. In addition, the NW (e.g., base station, AMF, etc.) can inform the UE of the wait time to be used to prevent multiple UEs from accessing the PLMN simultaneously during a disaster.

[0268] When selecting a PLMN in a disaster situation, the terminal can select a PLMN that takes the disaster situation into account. The AMF can transmit a list of PLMNs that can be used in a disaster situation to the terminal, and the NG-RAN can transmit SIB15 containing the disaster roaming configuration to the terminal.

[0269] Describes an example of disaster roaming support through minimal service interruption.

[0270] Depending on operator policy and national / regional regulations, 5GS may provide disaster roaming services to UEs in PLMNs experiencing disaster conditions. A UE will attempt disaster roaming only if:

[0271] - If there is no acceptable available PLMN (see TS 23.122 V18.6.0);

[0272] - When the UE is not in RM-registered and CM-connected state via a non-3GPP connection connected to 5GCN;

[0273] - When the UE cannot receive services through non-3GPP access via ePDG;

[0274] - If the UE supports disaster roaming service;

[0275] - If the Disaster Roaming Enabled in the UE is set to "Disaster Roaming Enabled in the UE" as specified in 3GPP TS 23.501 V18.5.0 S5.40.2 and the UE is configured by the HPLMN; and

[0276] - When a PLMN without disaster conditions can accept disaster inbound roamers from a PLMN with disaster conditions.

[0277] The terminal may receive SIB15 containing applicable disaster roaming information. For reference, TS38.331 v18.1.0 may be referenced regarding the SIB received by the terminal.

[0278] Upon receiving SIB15, the UE can forward disaster roaming information for each PLMN sharing the cell to the upper layer. For example, upon receiving SIB15, the AS layer of the UE can forward disaster roaming information for each PLMN sharing the cell to the NAS layer.

[0279] For example, SIB15 may include commonPLMNsWithDisasterCondition, and applicableDisasterInfoList.

[0280] commonPLMNsWithDisasterCondition is a list of PLMNs for which disaster conditions apply and disaster inbound roaming is allowed, which can be applied commonly to PLMNs sharing a cell.

[0281] For example, applicableDisasterInfoList can be a list representing disaster roaming information corresponding to the networks indicated in plmn-IdentityInfoList and npn-IdentityInfoList-r16. A network represents one entry in this list for each entry in plmn-IdentityInfoList, and then one entry for each entry in npn-IdentityInfoList-r16, so that there are as many entries in this list as there are in the combination of plmn-IdentityInfoList and npn-IdentityInfoList-r16. The first entry in this list represents disaster roaming information applicable to the network in the first entry in plmn-IdentityInfoList, the second entry in this list represents disaster roaming information applicable to the network in the second entry in plmn-IdentityInfoList, and so on. Each entry in this list can have one of the values ​​noDisasterRoaming, disasterRelatedIndication, commonPLMN, or dedicatedPLMN. If an entry in this list has the noDisasterRoaming value, disaster inbound roaming is not allowed on this network. If an entry in this list has the commonPLMNs value, the PLMNs with disaster conditions indicated in the commonPLMNsWithDisasterCondition field apply to this network. If an entry in this list has the dedicatedPLMNs value, the listed PLMNs are PLMNs with disaster conditions that allow disaster inbound roaming for the network corresponding to this entry. For SNPNs, the network indicates the noDisasterRoaming value.

[0282] NG-RAN can inform the terminal of the PLMN list to be used in disaster roaming conditions or whether the cell is disaster-related.

[0283] The terminal can select a PLMN based on the DisasterRelatedIndication broadcast by the NG-RAN or a dedicated PLMN, as shown in the example below. Additionally, the terminal can select a PLMN based on disaster-related information received and stored from the network, as shown in the example below.

[0284] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0285] FIG. 7 is an example of a PLMN selection procedure and a registration procedure according to one embodiment of the disclosure of the present specification.

[0286] 1. NG-RAN can broadcast System Information Block (SIB).

[0287] For example, the SIB may contain information related to disaster roaming. For example, the SIB may contain a disaster-related indicator and / or related PLMN information.

[0288] 2. The UE can determine the PLMN based on disaster conditions.

[0289] For example, the UE determines the PLMN determined by the UE based on disaster conditions.

[0290] For example, a UE may select a PLMN based on disaster-related information received from the NG-RAN. For example, a UE may select a PLMN based on disaster-related information received from the NG-RAN and disaster-related information received from the AMF. For example, a UE may receive information from the AMF regarding whether to activate disaster-related information based on procedures such as the UPU, and then select a PLMN.

[0291] 3. The UE may perform a PLMN selection procedure. For example, the UE may perform a PLMN selection procedure using a PLMN associated with a disaster state determined by the NG-RAN.

[0292] 4. The UE can send a registration request message to the AMF.

[0293] The registration request message may include capability information related to supporting MINT, for example. For example, the registration request message may include a 5GS registration type related to disaster roaming initial registration (or mobility registration). For example, the registration request message may include a PLMN determined by the UE based on disaster conditions (UE-determined PLMN with disaster conditions).

[0294] 5. AMF can register UE in UDM.

[0295] For example, AMF can perform the Nudm_UECM_Registration service action for UDM.

[0296] For example, AMF can obtain subscriber data of UE for disaster roaming service based on local policy / settings from UDM.

[0297] In the example of Fig. 7, if registration is successful, step 6a may be performed, and if registration is unsuccessful, step 6b may be performed.

[0298] 6a. If registration is successful, AMF may send a registration acceptance message to the UE.

[0299] The registration acceptance message may include a disaster roaming registration result value. The disaster roaming registration result value may include a 5GS registration result.

[0300] 6b. If registration fails, AMF may send a registration rejection message to the UE.

[0301] Registration rejection messages may include a reason for rejection.

[0302] For example, a registration rejection message may include rejection reason #80 (5GMM cause #80). Rejection reason #80 may relate to disaster roaming for the determined PLMN with disaster condition not allowed.

[0303] For example, a registration rejection message may include rejection reason #80 (5GMM cause #80). Rejection reason #80 may relate to disaster roaming for the determined PLMN with disaster condition not allowed.

[0304] For example, a registration rejection message may include rejection reason #11. Rejection reason #11 may relate to PLMN not allowed.

[0305] For example, a registration rejection message may include rejection reason #13. Rejection reason #13 may relate to roaming not allowed in this tracking area.

[0306] Information related to disaster roaming may be stored in the SIM and ME of the terminal, as in the example below.

[0307] For example, EF of SIM DRI can store one or more of the following information. For reference, EF DRI is a file stored in the SIM. For example, EF stands for Elementary File. DRI stands for Disaster Roaming indicator. SIM - EF DRI In relation to this, 3GPP TS 31.102 V18.3.0 S4.4.11.17 can be referenced:

[0308] - Whether disaster roaming is enabled. Can contain True or False.

[0309] - Disaster roaming parameter indicator status

[0310] - Disaster roaming wait range

[0311] - Disaster roaming return range

[0312] - Applicability indicator for "list of PLMN(s) to be used in disaster condition" provided by VPLMN

[0313] - "List of PLMN(s) to be used in disaster conditions" provided by HPLMN

[0314] For example, the ME may store one or more of the following information. With respect to the ME, reference may be made to Annex C in TS24.501 v18.6.0:

[0315] - One or more "PLMN Lists to Use in Disaster Situations" and the PLMN IDs of the PLMNs that provided them.

[0316] - Indication of whether disaster roaming is enabled

[0317] - Disaster roaming wait range

[0318] - Disaster roaming return range

[0319] - Applicability indicator for the "List of PLMNs to be used in disaster situations" provided by VPLMN.

[0320] To change the parameters stored in the terminal, at least one of the procedures according to the examples of FIGS. 8 to 10 may be performed.

[0321] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0322] FIG. 8 is an example of a registration procedure according to one embodiment of the disclosure of the present specification.

[0323] 1. The UE can send a registration request message to the AMF.

[0324] The registration request message may include capability information related to supporting MINT, for example.

[0325] 2. AMF may send a registration acceptance message to the UE.

[0326] For example, the registration acceptance message may include at least one of a list of PLMNs to be used in disaster conditions, a disaster roaming standby range, and / or a disaster roaming reversion range.

[0327] 3. The UE may perform actions related to storing a “list of PLMN(s) to be used in disaster condition”.

[0328] For example, the actions according to step 3 may include one or more of the following actions:

[0329] - The UE may delete the "PLMN list to be used in disaster conditions" stored in the ME together with the PLMN ID of the RPLMN (if the PLMN ID of the RPLMN exists).

[0330] - The UE may store in the ME a "PLMN list to be used in disaster conditions" including the PLMN list to be used in disaster conditions along with the PLMN ID of the RPLMN.

[0331] - The UE can store the disaster roaming standby range included in the disaster roaming standby range IE of the ME.

[0332] - The UE can store the disaster return standby range included in the disaster return standby range IE in the ME.

[0333] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0334] FIG. 9 is an example of a UE configuration update procedure according to one embodiment of the disclosure of the present specification.

[0335] 1. AMF can send a configuration update command message to the UE.

[0336] For example, the configuration update command message may include at least one of a list of PLMNs to be used in a disaster condition, a disaster roaming standby range, and / or a disaster roaming reversion range.

[0337] 2. The UE may perform actions related to storing a "list of PLMN(s) to be used in disaster conditions." For example, the UE may perform the same actions as step 3 of FIG. 8.

[0338] Based on the procedure according to the example of FIG. 8 or FIG. 9, one or more of the following information stored in the ME may be changed: one or more "PLMN lists to use in disaster situations" and the PLMN ID of the PLMN providing the list, the disaster roaming wait range, and / or the disaster roaming return range.

[0339] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0340] FIG. 10 is an example of a UE parameter update procedure according to one embodiment of the disclosure of the present specification.

[0341] 1. AMF can send a DL NAS Transport message to the UE.

[0342] For example, a DL NAS Transport message may include a UE parameter update transparent container (UE parameter update transport container). The UE parameter update transparent container may be a payload container Information Element (IE).

[0343] The UE parameter update transparent container may include a UE parameter update data set. The type of the UE parameter update data set may be set to disaster roaming information update data.

[0344] For example, the UE parameter update data set may include at least one of an indication of whether disaster roaming is enabled, an applicability indication of a "list of PLMNs to use in disaster situations" provided by the VPLMN.

[0345] 2. The UE may perform actions related to storing a “list of PLMN(s) to be used in disaster condition”.

[0346] For example, the actions according to step 2 may include one or more of the following actions:

[0347] - The UE may store in the ME an indication of the applicability of the “List of PLMNs to be used in disaster situations” provided by the VPLMN included in the disaster roaming information update data.

[0348] - The UE may store in the ME an indication of whether disaster roaming is activated in the UE, which is included in the disaster roaming information update data.

[0349] - If the REG bit of the UE parameter update data set is “re-register”, the UE may wait until entering 5GMM-IDLE mode and then initiate the registration procedure for mobility registration update.

[0350] For example, based on the procedure according to the example of FIG. 10, one or more of the following information stored in the ME may be changed: an indication of whether disaster roaming is enabled, an applicability indicator for the "PLMN list to use in disaster situations" provided by the VPLMN.

[0351] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0352] FIG. 11 is an example of transmitting disaster-related system information according to one embodiment of the disclosure of the present specification.

[0353] The NG-RAN can broadcast SIBs (e.g., SIB15). Note that in the disclosure of this specification, the NG-RAN and base station may be referred to as terms with the same meaning.

[0354] SIB15 contains configuration of disaster roaming information

[0355] i) PLMN ID

[0356] ii) ApplicableDisasterInfo (Choice: Select one of the parameters below)

[0357] -noDisasterRoaming

[0358] -disasterRelatedIndication

[0359] -commonPLMN

[0360] -One or more dedicated PLMN IDs

[0361] SIB15 may contain information related to disaster roaming (e.g., disaster roaming information settings). SIB15 may contain the following information:

[0362] i) PLMN ID; and

[0363] ii) ApplicableDisasterInfo, which may include at least one of the following:

[0364] - noDisasterRoaming;

[0365] - disasterRelatedIndication;

[0366] - commonPLMN;

[0367] - one or more dedicated PLMN IDs; or

[0368] - A list of one or more PLMN(s) with disaster conditions for which disaster roaming services are offered by the available PLMN(s).

[0369] Referring to Figure 11, the following operations can be performed.

[0370] 1. NG-RAN can broadcast SIB15 to UE.

[0371] For example, SIB15 may include a PLMN ID and information related to disaster roaming (e.g., applicable disaster information). For example, the disaster roaming-related information may be noDisasterRoaming, disasterRelatedIndication, or one or more dedicated PLMN IDs.

[0372] 2. The UE may or may not perform actions related to disaster conditions.

[0373] For example, if the information related to disaster roaming is noDisasterRoaming, the UE may not perform the action of determining the PLMN based on the disaster condition.

[0374] In step 2 of the example of FIG. 11, if the UE performs an action related to a disaster condition, the UE may determine a PLMN based on the disaster condition. Below, examples of case 1 and case 2 are described. Case 1 is an example where the information related to disaster roaming is a DisasterRelatedIndication, and case 2 is an example where the information related to disaster roaming includes a PLMN ID.

[0375] <Case 1의 동작>

[0376] For example, if the information related to disaster roaming is DisasterRelatedIndication, the UE can determine the PLMN based on the disaster condition.

[0377] a) If the country of the MS's RPLMN matches the country of the PLMN where the NG-RAN cell broadcasts a "disaster related indication" and the MS's RPLMN is allowed, the MS may consider the MS's RPLMN to be the PLMN determined by the UE based on the disaster condition.

[0378] b) If condition a) is not met, the MS may determine the PLMN determined by the UE based on the disaster condition from the acceptable PLMN in the following order, provided that the country of the acceptable PLMN matches the country of the PLMN from which the NG-RAN cell broadcasts the "disaster related indication":

[0379] - HPLMN or EHPLMN with highest priority;

[0380] - Each PLMN in the SIM's "User controlled PLMN selector with access technology" data file;

[0381] - Each PLMN in the SIM's "Operator controlled PLMN selector with access technology" data file.

[0382] <Case 2의 동작>

[0383] For example, if the information related to disaster roaming includes a PLMN ID, the UE can determine the PLMN based on the disaster condition. For example, if the information related to disaster roaming includes a list of one or more PLMNs that provide disaster roaming services in available PLMNs, the UE can determine the PLMN based on the disaster condition.

[0384] a) If the MS's RPLMN is included in the "List of one or more PLMNs for which disaster roaming service is provided by available PLMNs under disaster conditions" broadcast by any NG-RAN cell and is allowed, the MS may consider the MS's RPLMN to be the PLMN determined by the UE based on the disaster conditions of the NG-RAN.

[0385] b) If condition a) is not met, the MS may determine the PLMN determined by the UE to be used in the upper layer from the PLMNs according to the following conditions based on the disaster condition of the NG-RAN. For example, the MS may determine the PLMN determined by the UE from among the PLMNs included in the "List of PLMNs with one or more disaster conditions for which disaster roaming service is provided by available PLMNs" broadcast by the NG-RAN cell, and the PLMNs allowed in the following order:

[0386] - HPLMN or EHPLMN with the highest priority

[0387] - Each PLMN in the SIM's "User controlled PLMN selector with access technology" data file;

[0388] - Each PLMN in the SIM's "Operator controlled PLMN selector with access technology" data file.

[0389] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0390] FIG. 12 is an example of operations related to a PLMN selection procedure according to one embodiment of the disclosure of the present specification.

[0391] When a terminal selects a different PLMN, it may select one based on the priority of that PLMN.

[0392] In step (S1201), the UE may determine whether any PLMN / NG-RAN combination for a forbidden PLMN broadcasts the PLMN ID of the PLMN determined by the UE based on disaster conditions or broadcasts disaster-related indications (e.g., if the NG-RAN provides disaster roaming services and the PLMN is within the forbidden PLMN).

[0393] If any PLMN / NG-RAN combination for a forbidden PLMN broadcasts the PLMN ID of a PLMN determined by the UE based on a disaster condition or broadcasts a disaster-related indication (e.g., if the NG-RAN provides disaster roaming service and the PLMN is within the forbidden PLMN), step (S1202) is performed, and if any PLMN / NG-RAN combination for another forbidden PLMN broadcasts the PLMN ID of a PLMN determined by the UE based on a disaster condition or broadcasts a disaster-related indication, step (S1204) is performed.

[0394] In step (S1202), the UE can determine whether an indication of 'applicability of the 'PLMN list to be used in disaster situations' provided by the VPLMN' exists. If an indication of 'applicability of the 'PLMN list to be used in disaster situations' provided by the VPLMN' exists, step (S1203) can be performed. Otherwise, step (S1206) can be performed.

[0395] In step (S1203), the UE can determine whether the "PLMN list to be used in disaster conditions" associated with the PLMN ID of the PLMN determined by the UE based on the disaster conditions is stored in the ME. The UE can determine which PLMN (HPLMN or VPLMN) to perform the disaster condition PLMN list based on whether the "PLMN list to be used in disaster conditions" associated with the PLMN ID of the PLMN determined by the UE based on the disaster conditions is stored in the ME. If the "PLMN list to be used in disaster conditions" associated with the PLMN ID of the PLMN determined by the UE based on the disaster conditions is stored in the ME, step (S1205) can be performed. Otherwise, step (S1206) can be performed.

[0396] In step (S1205), if each PLMN in the "PLMN list to be used in disaster conditions" stored in the ME is associated with a PLMN ID of a PLMN determined by the UE based on the disaster condition, the PLMNs are sorted based on this list. For example, the UE may select a PLMN based on this list in which the PLMNs are sorted in order of priority.

[0397] In step (S1206), if each PLMN in the "PLMN list to be used in disaster situations" stored in the ME is associated with an HPLMN (if an HPLMN exists), the PLMNs are sorted based on this list. For example, the UE may select a PLMN based on this list in which the PLMNs are sorted in order of priority.

[0398] In step (S1204), the PLMN / NG-RAN combination for other prohibited PLMNs broadcasts the PLMN ID of the PLMN determined by the UE as a disaster condition or broadcasts a disaster-related indication.

[0399] In step (S1207), the UE may select a PLMN in any order. For example, the UE may select a PLMN randomly.

[0400] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0401] FIG. 13 is an example of a procedure related to registration acceptance according to one embodiment of the disclosure of the present specification.

[0402] 1. The UE can send a registration request message to the AMF via the NG-RAN.

[0403] The registration request message may include a 5GS registration type IE. The 5GS registration type IE may be a disaster roaming initial registration. The registration request message may include information related to a UE-determined PLMN with disaster conditions.

[0404] 2. The NG-RAN may forward the UE's registration request message to the AMF. Additionally, the NG-RAN may include a ULI in the registration request message. The ULI may include a cell ID.

[0405] 3. AMF may send a registration acceptance message to the UE.

[0406] For example, the registration acceptance message may include a 5GS registration result. For example, the 5GS registration result may include a disaster roaming registration result value.

[0407] For example, if a UE registers for a disaster roaming service, the disaster roaming registration result value may be set to No additional information.

[0408] For another example, if a UE registers for disaster roaming, the disaster roaming registration result value may be set to Request for registration for disaster roaming service accepted as registration not for disaster roaming service.

[0409] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0410] FIG. 14 is an example of an operation related to registration rejection according to one embodiment of the disclosure of the present specification.

[0411] 1~2. Steps 1 and 2 of FIG. 14 can be performed in the same manner as steps 1 and 2 of FIG. 13.

[0412] 3. AMF may send a registration rejection message to the UE.

[0413] A registration rejection message may include a rejection reason. For example, the rejection reason may be 5GMM cause #80. For example, 5GMM cause #80 may relate to "Disaster roaming for the determined PLMN with disaster conditions not allowed."

[0414] 4. The UE can perform actions related to PLMN selection.

[0415] For example, in step 4, the UE may perform actions such as the following examples:

[0416] - The UE enters the 5GMM-DEREGISTERED.PLMN-SEARCH state and can delete all 5G-GUTIs, last visited registered TAIs, TAI list and ngKSI.

[0417] - The UE shall not attempt to register disaster roaming services on a PLMN determined by the UE to be in a disaster condition for a period ranging from 12 to 24 hours.

[0418] - The UE will not attempt to register for disaster roaming services on this PLMN for a period ranging from 3 to 10 minutes.

[0419] - The UE can perform PLMN selection. 3GPP TS 23.122 V18.6.0 can be referenced.

[0420] As described in the various examples above, a terminal can perform PLMN selection in a disaster roaming situation. For example, the terminal can perform PLMN selection based on one or more of the following information: information broadcast from the NG-RAN, information received from the AMF and stored in the ME, information stored in the USIM, and / or ME information stored as pre-configuration.

[0421] When the terminal performs PLMN selection, the terminal selects a PLMN based on the list order of PLMN(s) to be used with disaster condition stored in the ME.

[0422] Meanwhile, according to the prior art, the order of PLMNs in the list of PLMN(s) to be used with disaster conditions has not been changed. That is, the order of PLMNs in the list of PLMN(s) to be used with disaster conditions is stored in the same order as the PLMN order indicated by the NW.

[0423] According to the prior art, even if the NW (e.g., AMF) sends a registration rejection message to the terminal along with the rejection reason, there is a problem that the List of PLMN(s) to be used with disaster condition of the ME stored in the terminal does not change. That is, even in this case, the order of PLMNs included in the List of PLMN(s) to be used with disaster condition of the ME does not change at all. For reference, the rejection reason can be, for example, rejection reason #80 (disaster roaming for the determined PLMN with disaster condition not allowed) or #11 (PLMN not allowed).

[0424] For example, in a disaster condition, the selectable lists may include PLMN #1 and PLMN #2, and the order of the lists may be PLMN #1, PLMN #2. In this case, the terminal selects PLMN #1 and attempts registration. If PLMN #1 is not capable of roaming in the disaster state (or disaster condition), the AMF may transmit Reject cause #80 to the terminal to inform that PLMN #1 is not capable of roaming in the disaster state (or disaster condition). In this case, according to the prior art, there is a problem that the terminal moves to the PLMN-SEARCH state and then selects PLMN #1 again based on the PLMN list to be used in the disaster state (or disaster condition) that the terminal stores in the ME. That is, according to the prior art, even if a registration rejection message is received from the network, the PLMN list that the terminal stores in the ME does not change at all, and therefore, there is a problem that the terminal re-performs registration with a PLMN that cannot be used in the disaster state (or disaster condition) according to the PLMN order of the previously stored PLMN list.

[0425] According to the prior art, even if a terminal receives a registration rejection message for PLMN#1, the terminal still determines PLMN#1 as the PLMN of its choice and attempts registration through the cell of that PLMN. If the terminal receives a rejection, a method is needed to select a PLMN in a disaster state (or disaster conditions) by using another PLMN included in the PLMN list.

[0426] According to one embodiment of the disclosure of the present specification, an example of a method for a terminal to select a PLMN is described.

[0427] When a terminal performs PLMN selection in a disaster roaming state, it can perform PLMN selection based on the following operations and a list of PLMN(s) to be used with disaster conditions.

[0428] For example, in a disaster situation, the network can inform the terminal of the PLMN where inbound roaming is possible. In this case, the terminal supporting MINT and storing disaster information can update the disaster information based on the rejection cause received from the network, thereby selecting the PLMN in the event of a disaster.

[0429] For example, the terminal may receive a registration rejection message (e.g., including Reject cause #80 or Reject cause #11). In this case, the terminal may update the PLMN list by changing the PLMN that received the reject cause #80 or #11 to the lowest priority in the list of PLMNs that can be transmitted in the disaster information. The terminal may select a PLMN based on the ranking of the PLMN in the updated PLMN list. After the terminal receives Reject cause #80 or #11, the updated PLMN list may be maintained until the terminal receives a new List of PLMNs to be used with disaster condition, such as a new registration acceptance message or a UE configuration update message.

[0430] For example, the terminal may receive a registration rejection message (e.g., including Reject cause #80 or reject cause #11). For example, if the terminal receives Reject cause #80 or Reject cause #11, the terminal may not consider (or exclude) the PLMN for which Reject cause #80 or Reject cause #11 was received for a certain period of time, and may select a PLMN based on a list of PLMNs available in relation to a disaster. For example, if the terminal receives Reject cause #80 or Reject cause #11, the terminal may not consider the PLMN related to Reject cause #80 or Reject cause #11 received from the network for a certain period of time or based on a preset time period. The terminal adds the PLMN for which the reject cause was received to the list of PLMNs that can be transmitted in disaster information after the preset time period or the time period received from the network has elapsed.

[0431] For example, the terminal may receive a registration rejection message (e.g., including Reject cause #80 or reject cause #11). In this case, while the terminal selects a PLMN for disaster roaming, the terminal may not consider the PLMN ID associated with the rejection reason (e.g., Reject cause #80 or reject cause #11) as a PLMN selection candidate. For example, the terminal may select the PLMN as a PLMN for disaster roaming service only if the registration procedure within the specific PLMN is not rejected with reception of 5GMM cause #80 ("Disaster roaming for the determined PLMN with disaster condition not allowed"), or if the registration procedure within the specific PLMN is rejected with reception of 5GMM cause #80 but the time for 5GMM cause #80 has elapsed. In other words, if the registration procedure within a specific PLMN is rejected with the reception of 5GMM cause #80 ("Disaster roaming for the determined PLMN with disaster condition not allowed") and the time for 5GMM cause #80 has not elapsed, the terminal does not select the PLMN.

[0432] The terminal may also manage a list of PLMN(s) to be used with disaster conditions stored by the terminal.

[0433] For example, a list of PLMN(s) to be used with disaster condition stored by a terminal may include PLMN #1, #2, and #3 in that order. The terminal may select PLMN #2 and transmit a registration request message to PLMN #2. In this case, the NW may transmit a Registration reject message with cause value #80 to the terminal. Then, the terminal may update the list of PLMN(s) to be used with disaster condition by changing the priority of PLMN#2, which received cause value #80, to the lowest priority. Then, the updated list of PLMN(s) to be used with disaster condition may include PLMN #1, #3, and #2 in that order. That is, in this example, the list may be updated so that PLMN#2 has the lowest priority.

[0434] For another example, a list of PLMN(s) to be used with disaster condition stored by a terminal may include PLMN #1, #2, and #3 in that order. The terminal may select PLMN #2 and transmit a registration request message to PLMN #2. In this case, the NW may transmit a Registration reject message with cause value #80 to the terminal. Then, the terminal may delete PLMN #2, which received cause value #80, from the list, thereby updating the list of PLMN(s) to be used with disaster condition. Then, the updated list of PLMN(s) to be used with disaster condition may include PLMN #1 and #3 in that order.

[0435] According to one embodiment of the disclosure of the present specification, a terminal may select a PLMN involved in a disaster.

[0436] For example, a terminal may configure a candidate for performing PLMN selection. In this case, the terminal may perform PLMN selection without considering a PLMN ID associated with reject cause #80 (e.g., “Disaster roaming for the determined PLMN with a disaster condition not allowed”) as a PLMN selection candidate.

[0437] For example, the PLMN ID associated with “Disaster roaming for the determined PLMN with disaster condition not allowed” may refer to a PLMN according to the following examples. For example, a terminal may initiate a registration procedure for a disaster roaming service. The AMF, which receives the registration request message transmitted by the terminal, may determine that the disaster roaming service cannot be performed to the PLMN determined under the disaster condition. In this case, the AMF may transmit a REGISTRATION REJECT message and 5GMM cause #80 (e.g., “Disaster roaming for the determined PLMN with disaster condition not allowed”) to the terminal. The PLMN ID associated with “Disaster roaming for the determined PLMN with disaster condition not allowed” may be the ID of the PLMN associated with the REGISTRATION REJECT message and 5GMM cause #80 transmitted by the AMF.

[0438] At this time, the AMF notifies the terminal of “Disaster roaming for determined PLMN with disaster condition not allowed” with 5GMM cause #80 in the REGISTRATION REJECT message. This may be because the PLMN is the terminal’s Forbidden PLMN or a PLMN for which no roaming agreement exists. Therefore, the terminal may not select the PLMN during PLMN selection.

[0439] For example, the following example illustrates the operation of a terminal selecting a PLMN in a disaster condition. During this PLMN selection process, the terminal may exclude a PLMN that has received 5GMM cause #80 (e.g., “Disaster roaming for determined PLMN with disaster condition not allowed”) from PLMN selection.

[0440] For example, according to the general PLMN selection of the terminal, the terminal selects and connects to an available and allowable PLMN, excluding a forbidden PLMN. For example, if an SKT subscriber attempts to connect to U+, since U+ is a Forbidden PLMN, U+ can notify the terminal that it is not allowed PLMN as reject cause #11. In this case, the terminal stores the PLMN of the U+ network in the forbidden PLMN. Alternatively, the Forbidden PLMN may be stored in the SIM card of the terminal. Afterwards, the terminal performs PLMN selection excluding the PLMN because the PLMN is a forbidden PLMN. However, since the government agency allows communication services to be used in disaster situations through the forbidden PLMN, the terminal can use the forbidden PLMN in disaster situations.

[0441] Therefore, among the forbidden PLMNs, the PLMNs that can be used in a disaster state can notify the terminal of whether disaster roaming is possible through the NG-RAN or AMF of the PLMN. The terminal can perform PLMN selection based on the information received from the NG-RAN and / or AMF. For example, the applicability of “lists of PLMN(s) to be used in disaster condition indication” provided by the VPLMN may be information indicating whether the terminal will use the list provided by the VPLMN or the list provided by the HPLMN. For example, if the applicability of “lists of PLMN(s) to be used in disaster condition indication” provided by the VPLMN is TRUE, the terminal can use the list provided by the VPLMN, and if this information is FALSE, the terminal can use the list provided by the HPLMN.

[0442] In the disclosure of this specification, the terminal may perform PLMN selection without considering the PLMN ID associated with cause #80 (e.g., “Disaster roaming for the determined PLMN with disaster condition not allowed”) as a PLMN selection candidate. For example, when the terminal performs PLMN selection in a disaster situation based on a list provided by the HPLMN or a list provided by the VPLMN and / or the conditions described in the examples of the disclosure of this specification, the PLMN ID associated with cause #80 is not considered.

[0443] When a terminal selects a PLMN in a disaster condition, the terminal can select a PLMN that satisfies the following conditions from the PLMN / NG-RAN combination broadcast by the PLMN that satisfies the following conditions in a disaster condition:

[0444] 1) The "applicability of lists of PLMN(s) to be used in disaster condition" indication provided by the VPLMN may be TRUE for any forbidden PLMN that broadcasts the PLMN ID of the UE-determined PLMN with a disaster condition. In this case, the UE may perform the following actions:

[0445] i. Based on the priority of the list of “list of PLMN(s) to be used in disaster condition” stored in the ME, the UE may select the PLMN associated with the PLMN ID of the UE-determined PLMN with disaster condition.

[0446] ii. If there is no PLMN ID associated with the PLMN ID of the UE-determined PLMN with disaster condition among the PLMN IDs in the “list of PLMN(s) to be used in disaster condition” in the ME, the UE selects the PLMN in the order of the list in the “list of PLMN(s) to be used in disaster condition” associated with the PLMN ID in the HPLMN. For example, the terminal stores a PLMN list to be used in such disaster situation by PLMN. For example, there is a PLMN list to be used in the HPLMN, a PLMN list to be used in VPLMN#1, or a PLMN list to be used in VPLMN#2. Therefore, the terminal can select the PLMN to be used in the disaster condition based on the PLMN list associated with the PLMN ID.

[0447] 2) The "applicability of 'lists of PLMN(s) to be used in disaster condition' indication provided by the VPLMN to any forbidden PLMN broadcasting the PLMN ID of the UE-determined PLMN with a disaster condition may be False. In this case, the UE may perform the following actions:

[0448] i. HPLMN selects the PLMN in the order of the “list of PLMN(s) to be used in disaster condition” list related to the PLMN ID.

[0449] 3) For PLMN / NG-RAN combinations of other forbidden PLMNs that broadcast a PLMN ID that broadcasts a disaster-related indication, the UE may randomly select a PLMN.

[0450] For example, a Forbidden PLMN (e.g., an NG-RAN included in the Forbidden PLMN) can broadcast a “list of one or more PLMN(s) with disaster conditions for which disaster roaming services are offered by the available PLMN.” In the event of a disaster, an NG-RAN capable of inbound roaming in a disaster can notify the UE of a “Disaster related indication” or a list of PLMNs that provide disaster roaming services among the available PLMNs, so that the UE can perform inbound roaming in a disaster situation.

[0451] For example, the Forbidden PLMN can notify the UE of the "Disaster-related indication" of the NG-RAN that allows inbound roaming during a disaster or the list of PLMNs that provide disaster roaming services. If the UE's RPLMN (Registered PLMN) is included in the PLMN list, the UE can consider the RPLMN as a UE-determined PLMN with a disaster condition.

[0452] The UE's RPLMN may not be in the "list of one or more PLMN(s) with disaster conditions for which disaster roaming services are offered by the available PLMNs" and the RPLMN may not be available. In this case, the UE may consider a PLMN included in the "list of one or more PLMN(s) with disaster conditions for which disaster roaming services are offered by the available PLMNs" as the UE-determined PLMN with disaster conditions.

[0453] While the terminal selects a PLMN for disaster roaming, the terminal may not consider PLMN IDs associated with rejection reasons (e.g., Reject cause #80 or reject cause #11) as PLMN selection candidates.

[0454] Based on these MINT (Minimization of Service Interruption)-related operations, the terminal can receive services. For example, when a disaster situation applies to a UE-determined PLMN with disaster conditions, the terminal can obtain services from the PLMN that provides the disaster roaming service.

[0455] The PLMN and related parameters to be used in Disaster Conditions may be preconfigured within the terminal's ME. Alternatively, the PLMN and related parameters to be used in Disaster Conditions may be updated through the Registration Procedure and Configuration Update procedures.

[0456] An example of selecting a PLMN for disaster roaming considering the PLMN associated with rejection reason value #80 is as follows.

[0457] According to the prior art, when the UE receives reason value #80 (the determined PLMN is not allowed for disaster roaming), the UE enters the PLMN-SEARCH state and performs a PLMN selection procedure. If the PLMN determined by the UE is included in the “PLMN list to be used in disaster conditions,” the UE must select a PLMN in the order included in the “PLMN list to be used in disaster conditions.” However, according to the prior art, the “PLMN list to be used in disaster conditions” in the ME of the UE does not change, so even if the UE selects a new PLMN within the list, there is a problem that the UE may select the same PLMN as the PLMN for which reason value #80 was received.

[0458] As described in various examples of the disclosure of this specification, an example is described in which a UE selects a PLMN by considering a PLMN rejected by the network with reason value #80 as a lower priority. For example, the UE may perform the PLMN selection procedure without considering the PLMN associated with reason value #80.

[0459] For example, when a UE selects a new PLMN, if the PLMN associated with reason value #80 is included in the “PLMN list to be used in disaster conditions”, the UE may consider the PLMN associated with reason value #80 as the lowest priority PLMN within the “PLMN list to be used in disaster conditions”.

[0460] For example, an example according to an embodiment of the disclosure of the present specification may be applied to the Automatic Network Selection Mode Procedure of 3GPP TS 23.122 V18.6.0 S4.4.3.1.1. In the following description, reference may be made to 3GPP TS 23.122 V18.6.0 S4.4.3.1.1.

[0461] The MS selects another PLMN / access technology combination, if available, and attempts registration. The MS attempts registration in the order allowed, i, ii, iii, iv, v, and vi:

[0462] i) MS attempts to register with the HPLMN (if the EHPLMN list is missing or empty) or with the highest priority EHPLMN available (if the EHPLMN list is present);

[0463] ii) The MS attempts to register for each PLMN / Access Technology combination (in order of priority) present in the SIM's "User Controlled PLMN Selector with Access Technology" data file;

[0464] iii) For each PLMN / Access Technology combination contained (in order of priority) in the "Operator Controlled PLMN Selector with Access Technology" data file of the SIM or stored (in order of priority) in the ME, the MS attempts registration for each PLMN / Access Technology combination;

[0465] iv) For high quality signals received in any order and for other PLMN / access technology combinations, the MS attempts registration;

[0466] v) For other PLMN / access technology combinations in descending order of signal quality, the MS attempts registration.

[0467] vi) A forbidden PLMN may broadcast the PLMN ID of a UE-determined PLMN with disaster condition or broadcast disaster-related indications. If the PLMN / NG-RAN combination for such a forbidden PLMN satisfies the following conditions, the MS may attempt registration for the PLMN / NG-RAN combination that satisfies the following conditions. For example, for the following conditions, the MS may not consider a PLMN ID associated with a rejection reason (e.g., Reject cause #80 or reject cause #11) as a candidate for PLMN selection:

[0468] a) If 'Applicability of PLMN list to be used in disaster situations provided by VPLMN' is set to true, the following explanation may apply:

[0469] - Within the "PLMN List to be used under disaster conditions" stored in the ME, for each PLMN associated with the PLMN ID of the PLMN (if any) determined by the MS based on the disaster condition, the MS may attempt registration based on the order of the PLMN list. In this case, the MS may attempt registration except for PLMNs that have been rejected (e.g., registration rejected) for the PLMN determined under the disaster condition; otherwise,

[0470] - In the "PLMN list to be used under disaster conditions" stored in the ME, there may not be a PLMN associated with the PLMN ID of the PLMN (if any) determined by the MS based on disaster conditions. In this case, if there is a PLMN ID associated with the PLMN of the HPLMN in the "PLMN list to be used under disaster conditions" stored in the ME, the MS may attempt registration based on the order of the PLMN list. In this case, the MS may attempt registration excluding PLMNs that have been rejected (e.g., registration rejected) for the PLMN determined under disaster conditions.

[0471] b) If the indication of 'Applicability of PLMN list for use in disaster situations' provided by VPLMN is set to false:

[0472] - Within the "PLMN List to be used in disaster conditions" stored in the ME, the MS may attempt registration for each PLMN associated with the HPLMN. In this case, the MS may attempt registration for PLMNs that are determined to be in disaster conditions, excluding PLMNs that are rejected (e.g., registration rejected).

[0473] vii) For PLMN / NG-RAN combinations that broadcast the PLMN ID of a PLMN determined by the MS with a disaster condition (MS-determined PLMN with disaster condition) or other prohibited PLMNs that broadcast disaster-related indications, the MS may attempt registration in any order. In this case, the MS may attempt registration in any order, including PLMNs that have been rejected (e.g., registration rejected) for PLMNs determined with a disaster condition.

[0474] Reference may also be made to 3GPP TS 23.122 V18.6.0 S4.4.3.1.1, “When following the above procedure, the following requirements apply.”

[0475] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0476] FIG. 15 illustrates an example of operations according to one embodiment of the disclosure of the present specification.

[0477] For reference, the procedure illustrated in FIG. 15 is merely an example, and the scope of the disclosure of this specification is not limited by the example in FIG. 15.

[0478] For example, with respect to the example of FIG. 15, the operations described in the examples of FIGS. 1 to 14 may also be applied. For example, even if operations, contents, etc. are not directly described in the example of FIG. 15, operations, contents, etc. described in various examples of the disclosure of this specification may be applied.

[0479] For reference, in various examples of the disclosure of this specification, MS and ME

[0480] In the example of FIG. 15, the first network entity may be a network entity related to mobility (e.g., AMF).

[0481] In step (S1501), the UE may transmit a registration request message to the first network entity.

[0482] For example, a registration request message may include capability information related to supporting Minimization of service interruption (MINT).

[0483] In step (S1502), the first network entity may transmit a message related to registration rejection to the UE. The message related to registration rejection may include a reason for rejection.

[0484] In step (S1503), the UE may select a PLMN. For example, the UE may select a PLMN for disaster roaming.

[0485] For example, the rejection reason may relate to disaster roaming not being allowed for the determined PLMN with disaster conditions. For example, the rejection reason may be reason #80. Based on the rejection reason relating to disaster roaming not being allowed for the determined PLMN with disaster conditions, the PLMN ID associated with the rejection reason may not be considered as a PLMN selection candidate during PLMN selection for disaster roaming.

[0486] For example, the UE may sequentially select a PLMN included in a list of PLMNs to be used in disaster conditions. For specific examples of how the UE selects a PLMN, reference may be made to the examples described in the various examples disclosed in this specification.

[0487] For example, based on the rejection reason received, the UE may change the priority of the PLMN associated with the rejection reason to the lowest priority within the list of PLMNs to be used in disaster conditions.

[0488] For example, based on a rejection reason received, the UE may delete the PLMN associated with the rejection reason from the list of PLMNs to be used in disaster conditions.

[0489] The UE may receive a registration acceptance message, a configuration update command message, or a Downlink (DL) Non Access Stratum (NAS) Transport message from the first network entity, which includes a list of PLMNs to be used in a disaster situation. This operation may be performed at any point between before step (S1501) and after step (S1503).

[0490] According to one embodiment of the disclosure of this specification, in a disaster situation, the network can inform the terminal of a PLMN that allows inbound roaming. In this case, the terminal, which supports MINT and stores disaster information, can effectively select a PLMN in a disaster situation. For example, the terminal can update the disaster information and select a PLMN based on the rejection cause received from the network.

[0491] According to one embodiment of the disclosure of the present specification, when a terminal receives Reject cause #80, the terminal may perform PLMN selection without considering the PLMN associated with the reject cause #80. For example, the terminal may select a PLMN based on the priority of the PLMN list that can be transmitted in the disaster status information. In this case, the terminal may check whether the PLMN information for which reject cause #80 was received is present in the PLMN list, update the PLMN associated with reject cause #80 to the list with the lowest priority, and then select the PLMN again.

[0492] This specification may have various effects.

[0493] Terminals can effectively select a PLMN during disaster situations. For example, this can prevent signaling waste, such as when a terminal performs unnecessary registration procedures and then selects a new PLMN. By quickly selecting a new PLMN, terminals in disaster situations can quickly receive services from that PLMN.

[0494] For example, when a NW rejects registration due to a disaster, the conventional problem of a terminal performing unnecessary registration procedures and then selecting a new PLMN, contrary to the NW's intention to not use the PLMN, can be resolved. This can eliminate signaling waste resulting from the terminal performing unnecessary operations.

[0495] The effects that can be achieved through the specific examples of this specification are not limited to the effects listed above. For example, a person with ordinary skill in the relevant technical field may understand or derive various technical effects from this specification. Accordingly, the specific effects of this specification are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of this specification.

[0496] For reference, the operation of the terminal (e.g., UE) described in this specification may be implemented by the devices of FIGS. 1 to 3 described above. For example, the terminal may be the first device (100) or the second device (200) of FIG. 2. For example, the operation of the terminal described in this specification may be processed by one or more processors (102 or 202). The operation of the terminal described in this specification may be stored in one or more memories (104 or 204) in the form of instructions / programs (e.g., instructions, executable codes) executable by one or more processors (102 or 202). The one or more processors (102 or 202) may control one or more memories (104 or 204) and one or more transceivers (105 or 206), and execute the instructions / programs stored in one or more memories (104 or 204) to perform the operation of the terminal (e.g., UE) described in the disclosure of this specification.

[0497] Additionally, the commands for performing the operations of the terminal described in the disclosure of this specification may be stored in a non-volatile computer-readable storage medium. The storage medium may be included in one or more memories (104 or 204). In addition, the commands recorded in the storage medium may be executed by one or more processors (102 or 202) to perform the operations of the terminal described in the disclosure of this specification.

[0498] For reference, the operation of a network node (e.g., AMF, SMF, PCF, UDM, etc.) or a base station (e.g., NG-RAN, gNB, RAN, eNB, (R)AN, etc.) described in this specification may be implemented by the devices of FIGS. 1 to 3 described below. For example, the network node or the base station may be the first device (100) or the second device (200) of FIG. 2. For example, the operation of the network node or the base station described in this specification may be processed by one or more processors (102 or 202). The operation of the terminal described in this specification may be stored in one or more memories (104 or 204) in the form of instructions / programs (e.g., instructions, executable codes) executable by one or more processors (102 or 202). One or more processors (102 or 202) may control one or more memories (104 or 204) and one or more transceivers (106 or 206), and execute instructions / programs stored in one or more memories (104 or 204) to perform operations of a network node or base station as described in the disclosure of this specification.

[0499] Additionally, the instructions for performing the operations of the network node or base station described in the disclosure of this specification may be stored in a non-volatile (or non-transitory) computer-readable storage medium having the instructions recorded thereon. The storage medium may be included in one or more memories (104 or 204). In addition, the instructions recorded in the storage medium may be executed by one or more processors (102 or 202) to perform the operations of the network node or base station described in the disclosure of this specification.

[0500] Although the preferred embodiments have been described above by way of example, the disclosure of this specification is not limited to these specific embodiments, and may be modified, changed, or improved in various forms within the scope described in the spirit and claims of this specification.

[0501] In the exemplary system described above, the methods are described based on a flowchart as a series of steps or blocks. However, the order of the steps described is not limited, and some steps may occur in a different order or simultaneously with other steps described above. Furthermore, those skilled in the art will understand that the steps depicted in the flowchart are not exclusive, and other steps may be included, or one or more steps in the flowchart may be deleted without affecting the scope of the invention.

[0502] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined to implement a device, and the technical features of the device claims of this specification may be combined to implement a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a method. Other implementations are within the scope of the claims.

Claims

1. A step of transmitting a registration request message to a first network entity related to mobility; A step of receiving a message related to a registration rejection including a reason for rejection from the first network entity; and Including the step of selecting a PLMN for disaster roaming, A method wherein, while selecting a PLMN for disaster roaming, a PLMN ID associated with the rejection reason is not considered as a PLMN selection candidate based on the rejection reason being related to disaster roaming for the determined PLMN with disaster condition not allowed.

2. In paragraph 1, The steps for selecting the above PLMN are: A method comprising the step of sequentially selecting PLMNs included in a list of PLMNs to be used in disaster conditions.

3. In paragraph 1 or 2, A method in which, based on the rejection reason received, the priority of the PLMN associated with the rejection reason within the list of PLMNs to be used in disaster conditions is changed to the lowest priority.

4. In any one of paragraphs 1 to 3, A method wherein, based on the reception of the rejection reason, a PLMN associated with the rejection reason is deleted from the list of PLMNs to be used in a disaster condition.

5. In any one of paragraphs 1 to 4, A method wherein the above registration request message includes capability information related to supporting Minimization of service interruption (MINT).

6. In any one of paragraphs 1 to 5, A method further comprising receiving a registration acceptance message, a configuration update command message, or a Downlink (DL) Non Access Stratum (NAS) Transport message from the first network entity, the registration acceptance message including a list of PLMNs to be used in a disaster condition.

7. One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; The actions performed based on the above instructions being executed by the one or more processors are: A device according to any one of claims 1 to 6.

8. At least one processor; and At least one memory storing instructions and being operably electrically connected to the at least one processor, An operation performed based on the above command being executed by the at least one processor: A device according to any one of claims 1 to 6.

9. A non-transitory computer-readable medium (CRM) that records commands, The above instructions, when executed by one or more processors, cause the one or more processors to perform a method according to any one of claims 1 to 6.

10. A step of receiving a registration request message from the device; and comprising the step of transmitting a message related to the registration rejection including the reason for the rejection to the device; A method wherein, based on the rejection reason being related to disaster roaming for the determined PLMN with disaster condition not allowed, while the device selects a PLMN for disaster roaming, the PLMN ID associated with the rejection reason is not considered as a PLMN selection candidate.

11. In paragraph 10, A method in which, based on the rejection reason being transmitted, the priority of the PLMN associated with the rejection reason within the list of PLMNs to be used in a disaster condition of the device is changed to the lowest priority.

12. In either of paragraphs 10 or 11, A method wherein, based on the rejection reason being transmitted, a PLMN associated with the rejection reason is deleted from the list of PLMNs to be used in a disaster condition of the device.

13. In any one of paragraphs 10 to 12, A method wherein the above registration request message includes capability information related to supporting Minimization of service interruption (MINT).

14. In any one of paragraphs 10 to 13, A method further comprising the step of transmitting to the device a registration acceptance message, a configuration update command message, or a Downlink (DL) Non Access Stratum (NAS) Transport message comprising a list of PLMNs to be used in a disaster condition.

15. One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; The actions performed based on the above instructions being executed by the one or more processors are: A device according to any one of claims 10 to 14.

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