Network node, terminal, and communication method

Abstract

This network node comprises: a reception unit that receives a sequence number and emergency information from a distribution source of the emergency information; and a transmission unit that transmits the sequence number and the emergency information to a terminal without changing the sequence number.

Description

Network node, terminal, and communication method

[0001] The present invention relates to notification of emergency information.

[0002] 3GPP (registered trademark) (3rd Generation Partnership Project) has introduced a wireless communication system called 5G or NR (New Radio) (hereinafter, the wireless communication system will be referred to as "5G" or "NR") in order to achieve a larger system capacity, a higher data transmission speed, and a lower latency in wireless sections. 5G introduces various wireless technologies to meet the requirement of achieving a throughput of 10 Gbps or more while reducing latency in wireless sections to 1 ms or less. Furthermore, 6G, a future communication system, is also being studied.

[0003] Furthermore, a public warning system (PWS) is provided that uses communication networks such as 5G to deliver emergency information from government agencies and the like to terminals (which may also be called mobile devices). In the PWS, government agencies and the like transmit emergency information from cell broadcast entities (CBEs). The emergency information is notified to the terminals via a communication network of a telecommunications carrier that includes a cell broadcast center (CBC). The terminal that receives the emergency information rings and displays the emergency information to the user (Non-Patent Document 1).

[0004] As described in Non-Patent Document 1, CBC assigns a serial number to emergency information received from a distribution source and transmits the serial number and the emergency information to a terminal. The terminal is equipped with a function for checking whether emergency information is duplicated, and this function prevents the terminal from sounding or displaying a message if it receives emergency information that is identical to emergency information that it has already received. Specifically, if the serial number of the emergency information that it has already received is the same as the serial number of the newly received emergency information, the terminal detects the duplication and does not sound or display a message.

[0005] 3GPP TS 23.041 V18.1.0 (2022-12)

[0006] A terminal may receive emergency information on one telecommunications carrier's network, ring, and display the emergency message, and then roam to another telecommunications carrier's network. A CBC is provided for each telecommunications carrier, and each CBC assigns its own sequence number. Therefore, even if the terminal receives the same emergency message after roaming as the one it received before roaming, the terminal will ring and display the emergency message again because the serial numbers before and after roaming are not the same. In other words, there is a problem in that the terminal cannot correctly check for duplicate emergency messages when roaming.

[0007] The present invention has been made in view of the above points, and aims to provide a technique that enables a terminal to correctly check for duplication of emergency information even when the terminal is roaming.

[0008] According to the disclosed technology, a network node is provided that includes: a receiving unit that receives a sequence number and the emergency information from a distributor of the emergency information; and a transmitting unit that transmits the sequence number and the emergency information to a terminal without changing the sequence number.

[0009] The disclosed technology provides a technology that enables a terminal to correctly check for duplication of emergency information even when the terminal is roaming.

[0010] FIG. 1 is a diagram for explaining an example of a communication system. FIG. 2 is a diagram for explaining an example of a communication system in a roaming environment. FIG. 3 is a diagram for explaining an example of a communication system in an embodiment of the present invention. FIG. 4 is a diagram for explaining a problem. FIG. 5 is a diagram for explaining Example 1. FIG. 6 is a diagram for explaining Example 2. FIG. 7 is a diagram for explaining Example 4. FIG. 8 is a diagram for explaining an example of the functional configuration of CBC 30 and CBE 50 in an embodiment of the present invention. FIG. 9 is a diagram for explaining an example of the functional configuration of terminal 20 in an embodiment of the present invention. FIG. 10 is a diagram for explaining an example of the hardware configuration of CBC 30, CBE 50, and terminal 20 in an embodiment of the present invention. FIG. 11 is a diagram for explaining an example of the configuration of vehicle 2001 in an embodiment of the present invention.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0012] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies are used as appropriate. However, the existing technologies include, but are not limited to, the existing LTE or the existing NR.

[0013] In the following, first, an example of the configuration of a network (communication system) used for communication in a PWS (Public Warning System) will be described, and then the system configuration and operation according to the present embodiment will be described. Note that, although a 5G network will be described below as an example of a network of a telecommunications carrier, the network used for communication in a PWS (Public Warning System) is not limited to a 5G network.

[0014] FIG. 1 is a diagram illustrating an example of a communication system corresponding to a mobile network. As shown in FIG. 1, this communication system is composed of a UE (terminal) and multiple network nodes. Hereinafter, it is assumed that one network node corresponds to each function, but multiple functions may be realized by one network node, or multiple network nodes may realize one function. Furthermore, the "connection" described below may be a logical connection or a physical connection.

[0015] The RAN 10 (Radio Access Network) is a network node having a radio access function and is connected to the UE 20, an AMF (Access and Mobility Management Function), and a UPF (User plane function). The RAN may also be called a base station. The AMF is a network node having functions such as terminating the RAN interface, terminating the NAS (Non-Access Stratum), registration management, connection management, reachability management, and mobility management. The UPF is a network node having functions such as a PDU (Protocol Data Unit) session point to the outside that interconnects with the DN (Data Network), packet routing and forwarding, and user plane QoS (Quality of Service) handling. The UPF and the DN constitute a network slice.

[0016] The AMF is connected to the UE, RAN, SMF (Session Management function), NSSF (Network Slice Selection Function), NEF (Network Exposure Function), NRF (Network Repository Function), UDM (Unified Data Management), AUSF (Authentication Server Function), PCF (Policy Control Function), and AF (Application Function). The AMF, SMF, NSSF, NEF, NRF, UDM, AUSF, PCF, and AF are network nodes interconnected via interfaces based on their respective services: Namf, Nsmf, Nnssf, Nnef, Nnrf, Nudm, Nausf, Npcf, and Naf.

[0017] The SMF is a network node that has functions such as session management, UE IP (Internet Protocol) address allocation and management, DHCP (Dynamic Host Configuration Protocol) function, ARP (Address Resolution Protocol) proxy, and roaming function. The NEF is a network node that has the function of notifying other NFs (Network Functions) of capabilities and events. The NSSF is a network node that has functions such as selecting a network slice to which a UE connects, determining the allowed NSSAI (Network Slice Selection Assistance Information), determining the NSSAI to be configured, and determining the AMF set to which the UE connects. The PCF is a network node that has the function of controlling network policies. The AF is a network node that has the function of controlling application servers. The NRF is a network node that has the function of discovering NF instances that provide services. The UDM is a network node that manages subscriber data and authentication data. The UDM is connected to a UDR (User Data Repository) that stores the data.

[0018] 2 is a diagram illustrating an example of a communication system in a roaming environment. As shown in FIG. 2, the network is made up of a UE 20 and a plurality of network nodes.

[0019] The SEPP is a non-transparent proxy that filters control plane messages between PLMNs (Public Land Mobile Networks). The vSEPP shown in Figure 2 is a SEPP in a visited network, and the hSEPP is a SEPP in a home network.

[0020] As shown in Fig. 2, UE 20 is in a roaming environment connected to a RAN and an AMF in a Visited PLMN (VPLMN). The VPLMN and a Home PLMN (HPLMN) are connected via a vSEPP and an hSEPP. UE 20 can communicate with a UDM in the HPLMN via the AMF in the VPLMN, for example.

[0021] (Regarding PWS) The PWS is an emergency information distribution infrastructure that distributes emergency information (warning messages) from administrative agencies and the like to terminals 20. In this embodiment, a communication system in this emergency information distribution infrastructure will be described.

[0022] An example of a communication system according to the present embodiment is shown in Fig. 3. As shown in Fig. 3, the communication system includes a CBE (Cell Broadcast Entity) 50, a CBC (Cell Broadcast Center) 30, an AMF 40, a base station 10, and a terminal 20. In the example of Fig. 3, the CBC 30, the AMF 40, the base station 10, and the terminal 20 are present in a network of a telecommunications carrier A.

[0023] Fig. 3 shows an example in which a 5G network is used. For example, when an LTE network is used, an MME 40 is used instead of an AMF 40. Therefore, in Fig. 3, the MME is shown in parentheses. The CBE 50, CBC 30, AMF 40, and base station 10 are all examples of network nodes. In 5G, the CBC may be called a CBCF (Cell Broadcast Center Function).

[0024] Although an example using the AMF 40 will be described below, even if the AMF 40 is replaced with another network node (such as an MME), the operation related to the present invention is the same.

[0025] The CBE 50 is a network node of a distributor of emergency information (for example, a government agency). The CBE 50 creates emergency information and transmits the emergency information to the CBC 30.

[0026] More specifically, the emergency information in this embodiment is, for example, a CBS (Cell Broadcast Service) message described in Non-Patent Document 1. The CBS message consists of one or more CBS pages. Each CBS page has a predetermined data length.

[0027] The CBC 30 is connected to one or more AMFs 40. The CBC 30 is also connected to one or more CBEs 50. Figure 3 shows one CBE 50 and one AMF 40 connected to the CBC 30.

[0028] The CBC 30 transmits (specifically, broadcasts) the emergency information received from the CBE 50 to the terminal 20. The emergency information is transmitted to the base station 10 via the AMF 40, and then transmitted from the base station 10 to the terminal 20. The terminal 20 that receives the emergency information rings and displays the emergency information to the user. Note that the terminal 20 may be configured to either ring or display the emergency information.

[0029] In the conventional technology disclosed in Non-Patent Document 1, the CBC 30 issues (assigns) a serial number (SN: Sequence Number) to the emergency information received from the CBE 50, and transmits the emergency information to which the SN has been assigned.

[0030] The terminal 20 has a function for checking whether emergency information is duplicated (duplication detection function). When the terminal 20 receives emergency information that is the same as emergency information that has already been received, the terminal 20 does not ring or display any message.

[0031] Specifically, if the terminal 20 receives emergency information having the same SN as that assigned to emergency information that has already been received within a predetermined time, the terminal 20 does not ring or display.

[0032] (Regarding the Problem) It is assumed that the terminal 20 roams from a network of a certain telecommunications carrier A to a network of another telecommunications carrier B. Possible examples of roaming include roaming from a network of a telecommunications carrier A in Japan to a network of a telecommunications carrier B in another country, and roaming from a network of a telecommunications carrier A within one country (for example, within Japan) to a network of another telecommunications carrier B.

[0033] Currently, domestic roaming is not available in Japan, but in the future, roaming between domestic telecommunications carriers may be offered, with the aim of creating an environment where communication services can be used continuously, even in emergencies, for example.

[0034] In this embodiment, it is assumed that a CBC 30 is provided for each telecommunications carrier. When the terminal 20 receives emergency information on the network of one telecommunications carrier and then roams to the network of another telecommunications carrier, the CBC 30 that transmits the emergency information to the terminal 20 is changed.

[0035] Since the CBC 30 of each carrier assigns its own SN to emergency information, even if the same emergency information is distributed from the same source, the SN assigned to the information will be different among multiple carriers. Therefore, when a roaming terminal 20 receives emergency information that is the same as emergency information that it has already received before roaming, it cannot properly check for duplication and will ring and display the same emergency information.

[0036] The above problem will be described in more detail with reference to Fig. 4. In the example shown in Fig. 4, the terminal 20 roams from the network of the communication carrier A to the network of the communication carrier B. The network of the communication carrier A includes a CBC 30A, an AMF 40A, and a base station 10A, and the network of the communication carrier B includes a CBC 30B, an AMF 40B, and a base station 10B.

[0037] In S1, CBE 50 distributes emergency information. CBC 30A and CBC 30B each receive the emergency information. In S2, CBC 30A and CBC 30B each assign an SN to the received emergency information and transmit the emergency information with the assigned SN. CBC 30A and CBC 30B each periodically transmit emergency information with the assigned SN for a certain period of time. Here, it is assumed that the SN assigned by CBC 30A is 1 and the SN assigned by CBC 30B is 2.

[0038] In S3, the terminal 20 before roaming receives the emergency information and sounds and displays a message. In S4, the terminal 20 roams to the network of communication carrier B. In S5, the terminal 20 receives from base station 10B the same emergency information as the emergency information received in S3. However, since the SN of the emergency information received in S3 and the SN of the emergency information received from base station 10B are different, the terminal 20 mistakenly recognizes in S5 that it has received emergency information different from the emergency information received in S3 and sounds and displays a message.

[0039] Below, embodiments 1 to 4 will be described as techniques for solving the above problems. Embodiment 1 is a basic embodiment, and embodiments 2 and 3 are implemented in combination with embodiment 1. Embodiment 4 is a modified example of embodiment 1. Embodiment 4 and embodiment 2 may be combined. Furthermore, the roaming described below is assumed to be roaming within one country. Here, it is assumed that the country is Japan, but since it is not limited to Japan, the country will be referred to as Country X below.

[0040] In the first embodiment, the CBE 50, which is the distributor of emergency information, issues a serial number (NSN: National Serial Number) whose identity can be guaranteed within country X when distributing the emergency information. Note that in this embodiment, the serial number is called an NSN (National Serial Number), but this name is just an example, and the serial number may be called by a name other than NSN.

[0041] Being able to guarantee the identity of the serial number means that for the same emergency information distributed from the same distribution source, the terminal 20 receives the same serial number regardless of the CBC that transmits the emergency information.

[0042] The terminal 20 performs a duplication check using the NSN. As a result, even when the terminal 20 is roaming, the terminal 20 can identify emergency information that is the same as emergency information that it has already received by using the NSN, and can avoid ringing or displaying the same emergency information.

[0043] In this embodiment, the NSN is guaranteed to be identical within one country, but the NSN may be guaranteed to be identical across multiple countries (or the world). In this case, even when the terminal 20 roams between multiple countries, it is possible to avoid ringing or displaying the same emergency information.

[0044] An example of the operation of the system in the first embodiment will be described with reference to Fig. 5. In the example shown in Fig. 5, similar to the example described in Fig. 3, the terminal 20 roams from the network of the telecommunications carrier A to the network of the telecommunications carrier B. The network of the telecommunications carrier A has a CBC 30A, an AMF 40A, and a base station 10A, and the network of the telecommunications carrier B has a CBC 30B, an AMF 40B, and a base station 10B. The CBE 50, each network node of the telecommunications carrier A, and each network node of the telecommunications carrier B are located in country X.

[0045] In S101, the CBE 50 distributes emergency information and issues an NSN corresponding to the emergency information. Here, it is assumed that NSN = 2. The CBE 50 may assign an NSN to the emergency information and distribute the emergency information with the NSN, or may distribute the emergency information and the NSN as separate information. The CBC 30A and CBC 30B each receive the emergency information and the NSN.

[0046] In S102, CBC 30A and CBC 30B each transmit the emergency information with the received NSN. In other words, CBC 30A and CBC 30B each transparently forward the NSN received from CBE 50 without assigning a new SN or changing the received NSN.

[0047] It should be noted that each of CBC 30A and CBC 30B may issue a new SN that is the same as the received NSN. This "SN that is the same as the received NSN" will also be referred to as the NSN.

[0048] Each of CBC 30A and CBC 30B periodically transmits emergency information with an assigned NSN for a certain period of time.

[0049] In S103, the terminal 20 before roaming receives the emergency information and rings and displays it. In S104, the terminal 20 roams to the network of communication carrier B. In S105, the terminal 20 receives from base station 10B the same emergency information as the emergency information received in S103. Because the NSN assigned to the emergency information received in S103 and the NSN assigned to the emergency information received from base station 10B are the same, the terminal 20 recognizes that the emergency information received in S105 and the emergency information received in S103 are the same, considers them to be duplicates, and does not ring or display.

[0050] Note that CBC 30A and CBC 30B may each assign a message identifier (emergency information identifier) ​​that identifies the source (CBE 50) to the emergency information, and transmit the emergency information to which the message identifier and NSN are assigned. Terminal 20 may perform a duplication check using the NSN between emergency information items with the same message identifier.

[0051] According to the first embodiment, the terminal 20 can correctly check for duplication of emergency information even when roaming.

[0052] In Example 2, control using a duplication detection time will be described as an example of detailed operation of the terminal 20 when using the NSN described in Example 1. Here, the following duplication detection time will be used, which is the same as the duplication detection time disclosed in Non-Patent Document 1.

[0053] - 1 hour in Japan (MCC=440 or MCC=441) - 24 hours outside Japan (MCC other than those mentioned above) Note that the MCC is a three-digit mobile country code included in the PLMN (Public Land Mobile Network) number. The PLMN (Public Land Mobile Network) number is notified to the terminal 20 by the base station 10 in the cell in which the terminal 20 is located.

[0054] The terminal 20 can improve the efficiency of processing by performing a duplication check on emergency information received within a certain period of time specified by the duplication detection time.

[0055] An example of the operation of the terminal 20 using the overlap detection time will be described with reference to the flowchart in Figure 6. Here, it is assumed that the terminal 20 has already received emergency information with an NSN and is ringing and displaying it. In S201, the terminal 20 receives the emergency information with an NSN attached. This emergency information is called new emergency information.

[0056] In S202, the terminal 20 determines whether the terminal 20 is located in a Japanese cell based on the MCC acquired in the cell the terminal 20 is located in. If the determination result in S202 is Yes, the process proceeds to S203, and if No, the process proceeds to S206.

[0057] In S203, the terminal 20 determines whether the time from the time when the previously received emergency information was received to the time when the new emergency information was received is within one hour. If the determination result is Yes, the process proceeds to S204, and if the determination result is No, the process proceeds to S205.

[0058] In S204, the terminal 20 checks for duplication of emergency information by determining whether the NSNs of the previously received emergency information and the new emergency information are the same. In S205, the terminal 20 does not check for duplication.

[0059] In S206, the terminal 20 determines whether the time from the time when the previously received emergency information was received to the time when the new emergency information was received is within 24 hours. If the determination result is Yes, the process proceeds to S207, and if the determination result is No, the process proceeds to S208.

[0060] In S207, the terminal 20 checks for duplication of emergency information by determining whether the NSNs of the previously received emergency information and the new emergency information are the same. In S208, the terminal 20 does not check for duplication.

[0061] According to the second embodiment, it is highly possible to avoid unnecessary duplication checks, and the duplication check process can be made more efficient.

[0062] (Example 3) Depending on the function of the CBC 30, even when the CBC 30 receives an NSN and emergency information from the CBE 50, it is assumed that the CBC 30 will assign an existing SN to the emergency information as in the prior art. In this case, for example, the CBC 30 may transmit the NSN to be transparently forwarded and the assigned SN together with the emergency information. In this case, the terminal 20 receives the NSN, SN, and emergency information.

[0063] In this way, in the third embodiment, when the terminal 20 receives both the SN and the NSN, the terminal 20 prioritizes the NSN. For example, in the case shown in Fig. 5, when the terminal 20 is in the area of ​​the network of the telecommunications carrier A, it receives emergency information with NSN = 2 and SN = 1 and rings and displays the emergency information. Then, after roaming to the telecommunications carrier B, it receives emergency information with NSN = 2 and SN = 2. In this case, since the terminal 20 prioritizes the NSN over the SN, it determines whether the NSN is the same before and after roaming, and since it is the same, it does not ring or display the emergency information.

[0064] According to the third embodiment, the operation of the terminal 20 when the terminal 20 receives both the SN and the NSN becomes clear.

[0065] (Fourth embodiment) In the case where the CBE 50 does not issue an NSN, information may be exchanged among a plurality of CBCs 30 that are roaming targets, so that the plurality of CBCs 30 that receive emergency information from the CBE 50 may issue the same SN.

[0066] An example of the operation of the fourth embodiment will be described with reference to Fig. 7. In the example of Fig. 7, the CBC 30A of the communication carrier A recognizes that the CBC 30B is a CBC of the communication carrier B that is a target of roaming from the communication carrier A, and holds information necessary for communication with the CBC 30B (such as the IP address of the CBC 30B).

[0067] Similarly, CBC30B of telecommunications carrier B recognizes that CBC30A is a CBC of telecommunications carrier A that is the target of roaming from telecommunications carrier B, and holds the information necessary to communicate with CBC30A (such as the IP address of CBC30A).

[0068] In S301, the CBE 50 distributes emergency information. The CBC 30A and the CBC 30B each receive the emergency information.

[0069] In S302, CBC 30A notifies CBC 30B of the received emergency information together with a message identifier that identifies the distribution source (CBE 50). Similarly, CBC 30B notifies CBC 30A of the received emergency information together with a message identifier that identifies the distribution source (CBE 50).

[0070] Through the above information exchange, CBC 30A recognizes that it has received the same emergency information as that received by CBC 30B, and CBC 30B recognizes that it has received the same emergency information as that received by CBC 30A. As a result, in S303, CBC 30A and CBC 30B assign the same SN to the received emergency information. CBC 30A and CBC 30B may determine the same SN according to a predetermined rule, or CBC 30A (or CBC 30B) may notify CBC 30B (or CBC 30A) of the SN they have determined, thereby allowing CBC 30A and CBC 30B to assign the same SN.

[0071] As described above, in S303, CBC 30A and CBC 30B each assign the same SN to the received emergency information and transmit the emergency information with that SN. CBC 30A and CBC 30B each periodically transmit the emergency information with the SN assigned for a certain period of time. Here, it is assumed that the SN assigned by CBC 30A and CBC 30B is 1.

[0072] In S304, the terminal 20 before roaming receives the emergency information and sounds and displays it. In S305, the terminal 20 roams to the network of communication carrier B. In S306, the terminal 20 receives from base station 10B the same emergency information as the emergency information received in S304. Since the SN assigned to the emergency information received in S304 and the SN assigned to the emergency information received from base station 10B are the same, the terminal 20 recognizes that the emergency information received in S306 and the emergency information received in S304 are the same, considers them to be duplicates, and does not sound or display.

[0073] According to the fourth embodiment, the terminal 20 can correctly check for duplication of emergency information even when roaming.

[0074] (Effects of the embodiment) According to the technology of the present embodiment, even when the terminal 20 roams, it is possible to correctly check for duplication of emergency information.

[0075] (Device Configuration) Next, an example of the functional configuration of the CBC 30 and the terminal 20 that perform the processes and operations described above will be described.

[0076] <CBC 30> Fig. 8 is a diagram showing an example of the functional configuration of the CBC 30. The CBC 30 is an example of a network node. Note that, like the CBC 30, the CBE 50 also has the configuration shown in Fig. 8.

[0077] As shown in Fig. 8, the CBC 30 includes a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 8 is merely an example. The names of the functional divisions and functional units may be any names as long as they can perform the operations according to the embodiment of the present invention.

[0078] The transmitter 110 has a function of generating signals to be transmitted to other network nodes and transmitting the signals via wired or wireless communication. The receiver 120 has a function of receiving various signals transmitted from other network nodes and acquiring, for example, information of a higher layer from the received signals. A communication unit including the transmitter 110 and the receiver 120 may be configured.

[0079] The setting unit 130 stores preset setting information and various setting information to be transmitted to other network nodes in a storage device, and reads the information from the storage device as needed. The control unit 140 controls the CBC 30. The function unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and the function unit related to signal reception in the control unit 140 may be included in the receiving unit 120. The transmitting unit 110 and the receiving unit 120 may be called a transmitter and a receiver, respectively.

[0080] <Terminal 20> Fig. 9 is a diagram showing an example of the functional configuration of the terminal 20. As shown in Fig. 9, the terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 9 is merely an example. The names of the functional divisions and functional units may be any as long as they can perform the operations related to the embodiment of the present invention.

[0081] The transmitter 210 creates a transmission signal from transmission data and transmits the transmission signal wirelessly. The receiver 220 receives various signals wirelessly and acquires higher layer signals from the received physical layer signals. The receiver 220 also has a function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, reference signals, and the like transmitted from a network node. A communication unit including the transmitter 210 and the receiver 220 may be configured.

[0082] The setting unit 230 stores various setting information received from the network node by the receiving unit 220 in a storage device, and reads it out from the storage device as needed. The setting unit 230 also stores setting information that is set in advance.

[0083] The control unit 240 controls the terminal 20. The functional unit in the control unit 240 related to signal transmission may be included in the transmitting unit 210, and the functional unit in the control unit 240 related to signal reception may be included in the receiving unit 220. The transmitting unit 210 and the receiving unit 220 may be called a transmitter and a receiver, respectively.

[0084] (Hardware Configuration) The block diagrams (FIGS. 8 and 9) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining software with the single device or the multiple devices.

[0085] Functions include, but are not limited to, judgment, determination, assessment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how these functions are implemented.

[0086] For example, the CBC 30, the CBE 50, and the terminal 20 according to an embodiment of the present disclosure may function as a computer that performs processing of the communication method of the present disclosure. Fig. 10 is a diagram illustrating an example of the hardware configuration of the CBC 30, the CBE 50, and the terminal 20 according to an embodiment of the present disclosure. The above-described CBC 30, the CBE 50, and the terminal 20 may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0087] In the following description, the term "device" can be interpreted as a circuit, a device, a unit, etc. The hardware configurations of the CBC 30, the CBE 50, and the terminal 20 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0088] Each function of CBC30, CBE50, and terminal 20 is realized by loading specified software (programs) onto hardware such as processor 1001, memory device 1002, etc., so that processor 1001 performs calculations, controls communication via communication device 1004, and controls at least one of reading and writing data in memory device 1002 and auxiliary memory device 1003.

[0089] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 140, control unit 240, etc. may be realized by the processor 1001.

[0090] The processor 1001 also loads programs (program codes), software modules, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002 and executes various processes in accordance with the programs. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 140 of the CBC 30 and CBE 50 shown in FIG. 8 may be implemented by a control program stored in the storage device 1002 and executed by the processor 1001. For example, the control unit 240 of the terminal 20 shown in FIG. 9 may be implemented by a control program stored in the storage device 1002 and executed by the processor 1001. While the above-described various processes have been described as being executed by a single processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may also be transmitted from a network via a telecommunications line.

[0091] The storage device 1002 is a computer-readable recording medium and may be configured, for example, by at least one of a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), etc. The storage device 1002 may also be called a register, a cache, a main memory, etc. The storage device 1002 can store executable programs (program codes), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

[0092] The secondary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. The above-mentioned storage medium may be, for example, a database, a server, or other appropriate medium including at least one of the storage device 1002 and the secondary storage device 1003.

[0093] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, a transmission / reception antenna, an amplifier unit, a transmission / reception unit, a transmission path interface, etc. may be realized by the communication device 1004. The transmission / reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated.

[0094] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0095] Furthermore, each device such as the processor 1001 and the storage device 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0096] Furthermore, the CBC 30, the CBE 50, and the terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0097] 11 shows an example configuration of a vehicle 2001. As shown in FIG. 11 , the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. Each aspect / embodiment described in the present disclosure may be applied to a communication device mounted on the vehicle 2001, and may be applied to the communication module 2013, for example. For example, the CBC 30, the CBE 50, or the terminal 20 may be included in the communication module 2013.

[0098] The drive unit 2002 is configured, for example, by an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user.

[0099] The electronic control unit 2010 is composed of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals are input to the electronic control unit 2010 from various sensors 2021 to 2029 provided in the vehicle 2001. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0100] The signals from the various sensors 2021 to 2029 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0101] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing (outputting) various types of information, such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 uses information acquired from external devices via the communication module 2013 or the like to provide various types of multimedia information and multimedia services to the occupants of the vehicle 2001. The information service unit 2012 may include input devices (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, a touch panel, etc.) that accept input from the outside, and may also include output devices (e.g., a display, a speaker, an LED lamp, a touch panel, etc.) that output information to the outside.

[0102] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driving burden on the driver, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. In addition, the driving assistance system unit 2030 transmits and receives various information via the communication module 2013 to realize the driving assistance function or the autonomous driving function.

[0103] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 29, which are provided in the vehicle 2001.

[0104] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a terminal, a network node, or the like.

[0105] The communication module 2013 may transmit, via wireless communication, to an external device at least one of signals from the various sensors 2021-2028 input to the electronic control unit 2010, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 2012. The electronic control unit 2010, the various sensors 2021-2028, the information service unit 2012, etc. may be referred to as input units that accept input.

[0106] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle 2001. The information service unit 2012 may be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the various information received from external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021 to 2029, etc. provided in the vehicle 2001.

[0107] Furthermore, when the communication module 2013 includes the CBC 30, the CBE 50, or the terminal 20, the communication module 2013 can perform the operations of the CBC 30, the CBE 50, or the terminal 20 described above.

[0108] This specification discloses at least the configurations described in the appendices below.

[0109] <Additional Notes> (Additional Item 1) A network node comprising: a receiving unit that receives a sequence number and the emergency information from a distributor of emergency information; and a transmitting unit that transmits the sequence number and the emergency information to a terminal without changing the sequence number. (Additional Item 2) The network node according to Additional Item 1, wherein the sequence number is the same among a plurality of network nodes that transmit the emergency information to the terminal. (Additional Item 3) A terminal comprising: a receiving unit that receives a sequence number identical to the sequence number and the first emergency information from a network node that received the sequence number and the first emergency information from a distributor of first emergency information; and a control unit that, when second emergency information has already been received, performs a duplication check between the first emergency information and the second emergency information using the sequence number. (Additional Item 4) The terminal according to Additional Item 3, wherein the control unit performs the duplication check when the first emergency information is received within a predetermined time after receiving the second emergency information. (Supplementary Item 5) A communication method executed by a network node, which receives a sequence number and emergency information from a source of the emergency information, and transmits the sequence number and the emergency information to a terminal without changing the sequence number.

[0110] Any of Supplementary Items 1 to 5 provides a technique that enables a terminal to correctly check for duplication of emergency information even when the terminal roams. Supplementary Item 2 enables a terminal to correctly check for duplication even when the CBC is changed due to roaming. Supplementary Item 4 enables an efficient duplication check.

[0111] (Supplementary Notes on the Embodiments) Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention; matters described in two or more items may be used in combination as needed, and matters described in one item may apply to matters described in another item (as long as there is no contradiction). Boundaries between functional units or processing units in functional block diagrams do not necessarily correspond to physical component boundaries. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the CBC 30 and terminal 20 have been described using functional block diagrams. However, such devices may be implemented using hardware, software, or a combination thereof. The software operated by the processor of the CBC 30 in accordance with an embodiment of the present invention and the software operated by the processor of the terminal 20 in accordance with an embodiment of the present invention may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium.

[0112] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling), broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0113] Each aspect / embodiment described in the present disclosure may be implemented using any of the following standards: LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or a decimal number)), FRA (Future Radio Access), NR (new Radio), New radio access (NX), Future generation radio access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.17 (WiMAX (registered trademark)), IEEE 802.19 (WiMAX (registered trademark)), IEEE 802.20 (WiMAX (registered trademark)), IEEE 802.21 (Wi-Fi (registered trademark)), IEEE 802.22 (WiMAX (registered trademark)), IEEE 802.23 (WiMAX (registered trademark)), IEEE 802.24 (WiMAX (registered trademark)), IEEE 802.25 (WiMAX (registered trademark)), IEEE 802.26 (WiMAX (registered trademark)), IEEE 802.27 (WiMAX (registered trademark)), IEEE 802.28 (WiMAX (registered trademark)), IEEE 802.29 (WiMAX (registered trademark)), IEEE 802.30 (WiMAX (registered trademark)), IEEE 802.31 (Wi-Fi (registered trademark)), IEEE 802.32 (WiMAX (registered trademark)), IEEE 802.33 (WiMAX (registered trademark)), IEEE 802.34 ( The present invention may be applied to at least one of systems using 802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), or other suitable systems, and next-generation systems that are extended, modified, created, or defined based on these systems. The present invention may also be applied to a combination of multiple systems (e.g., a combination of LTE and / or LTE-A with 5G).

[0114] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described herein may be rearranged unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order and are not limited to the particular order presented.

[0115] In this specification, a specific operation described as being performed by the base station 10 may be performed by its upper node in some cases. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the base station 10 and another network node other than the base station 10 (such as, but not limited to, an MME or an S-GW). Although the above example illustrates a case where there is one other network node other than the base station 10, the other network node may be a combination of multiple other network nodes (such as an MME and an S-GW).

[0116] The information, signals, etc. described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0117] Input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be transmitted to another device.

[0118] In the present disclosure, the determination may be made by a value represented by one bit (0 or 1), by a Boolean value (true or false), or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0119] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0120] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0121] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0122] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0123] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0124] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0125] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0126] In the present disclosure, terms such as "base station (BS)," "radio base station," "base station device," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. A base station may also be referred to by terms such as a macrocell, a small cell, a femtocell, and a picocell.

[0127] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be partitioned into multiple smaller areas, and each smaller area can also be provided with communication services by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage.

[0128] In the present disclosure, the base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

[0129] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," and the like may be used interchangeably.

[0130] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0131] At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object refers to a movable object, and may move at any speed. Naturally, this also includes cases where the mobile object is stationary. Examples of the mobile object include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and objects mounted thereon. The mobile object may also be a mobile object that moves autonomously based on an operational command. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may be a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0132] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple terminals 20 (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0133] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station may be configured to have the functions of the user terminal described above.

[0134] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0135] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0136] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0137] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0138] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0139] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0140] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0141] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0142] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0143] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0144] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0145] 10 Base station 30 CBC 40 AMF 50 CBE 110 Transmission unit 120 Reception unit 130 Setting unit 140 Control unit 20 Terminal 210 Transmission unit 220 Reception unit 230 Setting unit 240 Control unit 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device

Claims

1. A network node comprising: a receiving unit that receives a sequence number and emergency information from a source of the emergency information; and a transmitting unit that transmits the sequence number and the emergency information to a terminal without changing the sequence number.

2. The network node according to claim 1, wherein the sequence number is the same among a plurality of network nodes that transmit the emergency information to the terminal.

3. A terminal comprising: a receiving unit that receives a sequence number identical to the sequence number of a first emergency information and the first emergency information from a network node that received the sequence number and the first emergency information from a distributor of the first emergency information; and a control unit that, if second emergency information has already been received, uses the sequence number to perform a duplication check between the first emergency information and the second emergency information.

4. The terminal according to claim 3, wherein the control unit performs the duplication check when the first emergency information is received within a predetermined time after the second emergency information is received.

5. A communication method executed by a network node, which comprises receiving a sequence number and emergency information from a source of the emergency information, and transmitting the sequence number and the emergency information to a terminal without changing the sequence number.

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