Patent Publication Number: US-2023147513-A1

Title: Snpn-ran entity, distribution system, distribution method, and non-temporary computer readable medium

Description:
TECHNICAL FIELD 
     The present disclosure relates to a Stand-alone Non-Public Networks (SNPN)-Radio Access Network (RAN) entity, a distribution system, a distribution method, and a program. 
     BACKGROUND ART 
     In 3rd generation partnership project (3GPP), as a radio system for achieving higher-speed communication than long term evolution (LTE), a standard specification of a radio system called 5th Generation (5G) has been established. A communication system that achieves 5G (hereinafter, referred to as a 5G communication system) has a base station supporting 5G (hereinafter, referred to as a 5G base station) as a radio system, and a core network accommodating the base station supporting 5G (hereinafter, referred to as a 5G core network). In the 5G communication system, there are a form in which a communication carrier operates the 5G communication system in order to provide a service for a wide range of general users, and a form in which a provider or an enterprise being different from the communication carrier directly operates the 5G communication system without intervention of the communication carrier. In the 3GPP, stand-alone non-public networks (SNPN) are defined as a 5G communication system directly operated by an enterprise. Apart from a 5G base station and a 5G core network being operated by a communication carrier, the SNPN have a 5G base station and a 5G core network being operated directly by an enterprise. Location information of a communication terminal using the SNPN, subscriber information, and the like are registered in the 5G core network directly operated by the enterprise. Meanwhile, Non Patent Literature 1 discloses a technique for performing interworking with a 5G communication system provided by a communication carrier even in a case of the SNPN. 
     Herein, in the 3GPP, a specification of a public warning system (PWS) for distributing information in an emergency such as a disaster is defined. The PWS is used as an earthquake and tsunami warning system (ETWS) for distributing emergency information in Japan. Non Patent Literature 2 defines that emergency information to be distributed in the ETWS is also distributed to a communication terminal for which location information, subscriber information, and the like are not managed in a 5G communication system operated by a communication carrier. Therefore, even in a communication terminal in which location information, subscriber information, and the like are registered only in a 5G core network directly operated by an enterprise, it is necessary to be able to receive information distributed from the ETWS. 
     CITATION LIST 
     Non Patent Literature 
     Non Patent Literature 1: 3GPP TS23.501 V16.3.0 (2019-12) 
     Non Patent Literature 2: 3GPP TS25.304 V15.0.0 (2018-06) 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, Non Patent Literature 2 does not explicitly describe a cooperation procedure between the 5G communication system operated by the communication carrier and the SNPN. Therefore, a procedure of distributing emergency information distributed via the 5G communication system operated by the communication carrier to the SNPN is not clear. As a result, there is a problem that a communication terminal using the SNPN cannot receive the emergency information. 
     An object of the present disclosure is to provide an SNPN-RAN entity, a distribution system, a distribution method, and a program that are capable of distributing emergency information to a communication terminal using SNPN. 
     Solution to Problem 
     An SNPN-RAN entity according to a first example aspect of the present disclosure includes: a reception unit configured to receive, from a base station deployed in a network operated by a communication carrier, emergency information transmitted by using a first frequency used by the communication carrier; and a transmission unit configured to transmit, by using a second frequency used in a Stand-Alone Non-Public Network (SNPN), the emergency information to a communication terminal registered in the SNPN. 
     A distribution system according to a second example aspect of the present disclosure includes: a reception apparatus configured to receive, from a base station deployed in a network operated by a communication carrier, emergency information transmitted by using a first frequency used by the communication carrier; and an SNPN-RAN entity configured to transmit, by using a second frequency used in a Stand-Alone Non-Public Network (SNPN), the emergency information received from the reception apparatus to a communication terminal registered in the SNPN. 
     A distribution method according to a third example aspect of the present disclosure includes: receiving, from a base station deployed in a network operated by a communication carrier, emergency information transmitted by using a first frequency used by the communication carrier; and transmitting, by using a second frequency used in a Stand-Alone Non-Public Network (SNPN), the emergency information to a communication terminal registered in the SNPN. 
     A program according to a fourth example aspect of the present disclosure causes a computer to: receive, from a base station deployed in a network operated by a communication carrier, emergency information transmitted by using a first frequency used by the communication carrier; and transmit, by using a second frequency used in a Stand-Alone Non-Public Network (SNPN), the emergency information to a communication terminal registered in the SNPN. 
     Advantageous Effects of Invention 
     According to the present disclosure, it is possible to provide an SNPN-RAN entity, a distribution system, a distribution method, and a program that are capable of distributing emergency information to a communication terminal using SNPN. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a configuration diagram of an SNPN-RAN entity according to a first example embodiment; 
         FIG.  2    is a configuration diagram of a communication system according to a second example embodiment; 
         FIG.  3    is a diagram of an SNPN-RAN entity according to the second example embodiment; 
         FIG.  4    is a diagram showing a flow of processes for transmitting emergency information according to the second example embodiment; 
         FIG.  5    is a diagram showing a flow of processes for transmitting emergency information in the SNPN-RAN entity according to the second example embodiment; 
         FIG.  6    is a diagram showing a flow of processes for transmitting emergency information according to a third example embodiment; and 
         FIG.  7    is a configuration diagram of the SNPN-RAN entity according to each example embodiment. 
     
    
    
     EXAMPLE EMBODIMENT 
     First Example Embodiment 
     Example embodiments of the present disclosure will be described below with reference to the drawings. A configuration example of an SNPN-Radio Access Network (RAN) entity (hereinafter referred to as an SNPN-RAN)  10  according to a first example embodiment will be described by using  FIG.  1   . The SNPN-RAN  10  may be a computer device that operates by causing a processor to execute a program stored in a memory. The SNPN-RAN  10  includes a reception unit  11  and a transmission unit  12 . The components that compose the SNPN-RAN  10 , such as the reception unit  11  and the transmitter  12 , may be software or modules in which processing is executed by causing a processor to execute a program stored in a memory. Alternatively, the components that compose the SNPN-RAN  10  may be hardware such as circuits or chips. 
     The SNPN-RAN  10  may be a base station supporting 5G, the specification of which is defined in 3GPP as a radio communication system. For example, the SNPN-RAN  10  may be a gNB (a gNode B). 
     The reception unit  11  receives, from a base station deployed in a network operated by a communication carrier, emergency information transmitted by using a frequency used by the communication carrier. The network operated by the communication carrier may be referred to as a mobile network operator (MNO) network, a public land mobile network (PLMN), or the like. 
     The base station deployed in the network operated by the communication carrier may be, for example, a base station supporting 5G, the specification of which is defined in 3rd Generation Partnership Project (3GPP) as a radio communication system. The base station deployed in the network operated by the communication carrier may be, for example, a gNB (a gNode B). In the following description, the frequency used by the communication carrier is described using the term “carrier frequency”. 
     The emergency information includes a commercial mobile alert system (CMAS), an earthquake and tsunami warning system (ETWS), a Korean public alert system (KPAS), and information distributed in EU-ALERT, which are defined in Non Patent Literature 3. 
     The transmission unit  12  transmits, by using a frequency used in a Stand-Alone Non-Public Network (SNPN), the emergency information to a communication terminal registered in the SNPN. In the following description, the frequency used in the SNPN is described using the term “local frequency”. The transmission unit  12  transmits the emergency information to a communication terminal that belongs to an area where communication can be performed by using the local frequency. 
     As described above, the SNPN-RAN  10  transmits emergency information received from a base station deployed in a network operated by a communication carrier to a communication terminal that belongs to an area where communication can be performed by using a local frequency. By doing so, a communication terminal capable of performing communication using only the local frequency can receive emergency information transmitted in the network operated by the communication carrier. 
     Second Example Embodiment 
     Next, a configuration example of a communication system according to a second example embodiment will be described by using  FIG.  2   . The communication system in  FIG.  2    illustrates a configuration in which an MNO network  30  includes a SNPN  40 . That is, the SNPN  40  overlaps with some areas of the MNO network  30 . In other words, the MNO network  30  includes the SNPN  40 . Alternatively, some areas of the SNPN  40 , rather than the entire areas of the SNPN  40 , may overlap with some areas of the MNO network  30 . The some areas of the SNPN  40  overlapping the areas of the MNO network  30  may be, for example, areas formed by an SNPN-RAN  41  included in the SNPN  40  to perform radio communication. 
     The MNO network  30  includes a radio access network (RAN) entity (hereinafter, referred to as RAN)  31 , an access and mobility function (AMF) entity (hereinafter, referred to as AMF)  32 , a cell broadcast centre function (CBCF)/public warning system-interworking function (PWS-IWF) entity (hereinafter, referred to as CBCF/PWS-IWF)  33 , a cell broadcast entity (CBE)  34 , and a non-3GPP interworking function (N3IWF) entity (hereinafter, referred to as N3IWF)  35 . A user equipment (UE)  36  is a communication terminal held by a user who uses the MNO network  30 . 
     The RAN  31  is, for example, a base station supporting 5G as a radio system, and may be, for example, a gNB. The AMF  32  manages access and mobility related to the UE  36  held by a user using the MNO network  30 . Specifically, the AMF  32  manages location information of the UE  36 , and executes an authentication process of the UE  36  in cooperation with an authentication device (not illustrated). 
     The CBE  34  may be, for example, a server device and the like managed by an administrative agency that monitors an earthquake, a tsunami, or the like. The CBE  34  generates emergency information and transmits the generated emergency information to the CBCF/PWS-IWF  33 . The CBCF/PWS-IWF  33  is a device in which a CBCF entity and a PWS-IWF entity are integrated together. When receiving the emergency information from the CBE  34 , the CBCF/PWS-IWF  33  specifies a distribution area of the emergency information. For example, the CBCF/PWS-IWF  33  specifies a cell, a tracking area (TA), or an emergency area (EA) as a distribution area. The EA is a distribution area that can be uniquely set by a communication carrier regardless of the TA. 
     The N3IWF  35  communicates with a UE  43  via the SNPN  40 . The N3IWF  35  connects between different networks each other, and relays control data that is related to the UE  43  and is transmitted between the UE  43  and the AMF  32 . The control data may be referred to as control (C)-Plane data. The emergency information may be transmitted as C-Plane data. 
     The SNPN  40  includes the SNPN-RAN entity (hereinafter referred to as the SNPN-RAN)  41  and an SNPN-AMF entity (hereinafter referred to as an SNPN-AMF)  42 . The SNPN-RAN  41  may be a base station deployed in the SNPN. For example, the SNPN-RAN  41  may be a gNB supporting 5G as a radio system. The SNPN-RAN  41  receives information transmitted from the RAN  31 . Specifically, like the UE  36  located in a communication area formed by the RAN  31 , the SNPN-RAN  41  receives information. The communication area formed by the RAN  31  is an area in which the RAN  31  communicates with a communication terminal or the like by using a carrier frequency. That is, the SNPN-RAN  41  performs a reception operation similar to that performed by the UE  36  when the SNPN-RAN  41  communicates with the RAN  31 , and operates as a gNB when it communicates with the UE  43 . 
     The SNPN-AMF  42  is equivalent to a SNPN core network device. The SNPN-AMF  42  manages access and mobility related to the UE  43  held by a user using the SNPN  40 . Specifically, the SNPN-AMF  42  manages location information of the UE  43 , and executes the authentication process of the UE  43  in cooperation with an authentication device (not illustrated). The UE  43  can only perform communication via the SNPN-RAN  41  and the SNPN-AMF  42  when it is managed by the SNPN-AMF  42 . That is, the UE  43  cannot perform communication via the RAN  31  when it is managed by the SNPN-AMF  42 . 
     Next, a configuration example of the SNPN-RAN  41  according to the second example embodiment will be described with reference to  FIG.  3   . The SNPN-RAN  41  includes an MNO radio communication unit  48 , a data processing unit  45 , an SNPN radio communication unit  49 , an SNPN-RAN control unit  46 , and a 5GC communication unit  47 . The MNO radio communication unit  48  corresponds to the reception unit  11  shown in  FIG.  1   , and the SNPN radio communication unit  49  corresponds to the transmission unit  12  shown in  FIG.  1   . 
     The MNO radio communication unit  48  receives information transmitted from the RAN  31 . Like the UE  36  etc., the MNO radio communication unit  48  includes an antenna capable of receiving a signal having the carrier frequency used in the RAN  31  and a demodulation unit that demodulates received information. The MNO radio communication unit  48  receives System Information Block (SIB) information transmitted from the RAN  31 . The SIB information includes emergency information. For example, the emergency information is included in SIB6, SIB7, or the like specified in 3GPP. For example, SIB6 contains an ETWS primary notification, and SIB7 contains an ETWS secondary notification. The MNO radio communication unit  48  outputs the received SIB information to the data processing unit  45 . 
     Note that, when the MNO radio communication unit  48  receives SIB information from the RAN  31 , the SNPN-RAN  41  may be registered in the AMF  32  like in the case of the UE  36 . That is, the SNPN-RAN  41  may be in a state in which a Registration procedure with the AMF  32  is successfully completed. In this case, like the UE  36  registered in the AMF  32 , the SNPN-RAN  41  can perform communication in the MNO network  30  by using the carrier frequency. 
     Alternatively, when the MNO radio communication unit  48  receives SIB information from the RAN  31 , the SNPN-RAN  41  may not be registered in the AMF  32 . That is, the SNPN-RAN  41  may be in a state in which the Registration procedure with the AMF  32  is not executed or a state in which it is not successfully completed. A state in which the SNPN-RAN  41  is not registered in the AMF  32  as described above is referred to as a limited service state. In the MNO network  30 , a communication terminal can receive emergency information such as ETWS even in a limited service state. In other words, a communication terminal in a limited service state can only receive emergency information and cannot perform other communication. Regarding a procedure by which a communication terminal in a limited service state receives emergency information such as ETWS, a generally known procedure specified in 3GPP may be used, and thus a detailed description thereof will be omitted. 
     The data processing unit  45  extracts emergency information included in SIB information. In other words, the data processing unit  45  extracts parameters indicating emergency information included in SIB information. Further, the data processing unit  45  includes the extracted emergency information in information, a message, or the like to be transmitted to the UE  43  located in a communication area formed by the SNPN-RAN  41 . For example, the data processing unit  45  may set the emergency information in SIB information to be transmitted to the UE  43 . Alternatively, the data processing unit  45  may include the emergency information in information to be broadcast to the UE  43  located in a communication area formed by the SNPN-RAN  41 . The SIB information transmitted to the UE  43  may be similar to SIB information used in the MNO network  30 . That is, the UE  43  may set the emergency information in SIB  6  or SIB  7 . 
     The SNPN-RAN control unit  46  performs resource control, scheduling, or the like related to the UE  43  that communicates with the SNPN radio communication unit  49 . The 5GC communication unit  47  communicates with the SNPN-AMF  42 . 
     The SNPN radio communication unit  49  transmits emergency information to the UE  43 . The SNPN radio communication unit  49  may transmit SIB information including emergency information to the UE  43 . The SNPN radio communication unit  49  includes an antenna capable of transmitting a signal having a local frequency and a modulation unit that generates a signal having a local frequency. 
     Although it is shown in  FIG.  3    that the MNO radio communication unit  48  is included in the SNPN-RAN  41 , the MNO radio communication unit  48  may instead be installed at a position physically distant from the SNPN-RAN  41 . In this case, an apparatus including the MNO radio communication unit  48  may communicate with the SNPN-RAN  41  via a network, for example, through a cable. In this case, it is necessary for the apparatus including the MNO radio communication unit  48  to be installed in a communication area formed by the RAN  31 . On the other hand, the SNPN-RAN  41  may not be installed in the communication area formed by the RAN  31 . 
     Next, a flow of processes for transmitting emergency information according to the second example embodiment will be described with reference to  FIG.  4   . First, the AMF  32  transmits a Write-Replace Warning Request message to the RAN  31  (S 11 ). The AMF  32  receives the Write-Replace Warning Request message from the CBE  34  via the CBCF/PWS-IWF  33 . The Write-Replace Warning Request message received by the AMF  32  includes emergency information and a distribution area of the emergency information. The AMF  32  transmits the Write-Replace Warning Request message including the emergency information to the RAN  31  included in the distribution area included in the received Write-Replace Warning Request message. The AMF  32  may transmit, to the RAN  31 , a Write-Replace Warning Request message including information specifying a particular Cell as the distribution area. 
     The RAN  31  transmits the emergency information to the SNPN-RAN  41  as broadcast information (S 12 ). Although not shown in  FIG.  4   , the RAN  31  also transmits the broadcast information to a plurality of UEs including the UE  36  located in the communication area of the RAN  31 . The RAN  31  may repeatedly transmit the broadcast information to the SNPN-RAN  41 . When a distribution area is specified in the received Write-Replace Warning Request message, the RAN  31  transmits the broadcast information to the specified Cell. When a distribution area is not specified in the received Write-Replace Warning Request message, the RAN  31  transmits the broadcast information to all the Cells. 
     The RAN  31  transmits a Primary Notification and a Secondary Notification to the SNPN-RAN  41  as emergency information. In the Primary Notification, for example, a Warning Type is notified to the UE  43  by the SIB  6  which is the broadcast information. The Warning Type indicates, for example, a disaster type. In the Secondary Notification, for example, a Warning message is notified to the UE  43  by the SIB  7  as the broadcast information. The Warning message indicates, for example, the contents of a message. 
     The SNPN-RAN  41  transmits the emergency information received from the RAN  31  to the UE  43  as the broadcast information (S 13 ). The SNPN-RAN  41  receives the broadcast information transmitted from the RAN  31  by using a carrier frequency. Further, the SNPN-RAN  41  transmits the broadcast information to the UE  43  by using a local frequency. That is, the SNPN-RAN  41  extracts emergency information from the broadcast information transmitted by using the carrier frequency, and transmits the extracted emergency information to the UE  43  by using the local frequency. Further, the SNPN-RAN  41  may edit the contents of the emergency information to be transmitted to the UE  43  based on the emergency information received from the RAN  31 , and transmit the edited emergency information to the UE  43  by using the local frequency. For example, when the SNPN  40  is set in the factory, the edited emergency information of the SNPN-RAN  41  may be data that can be understood by various types of machines connected to the UE  43  and may, more particularly, be operation instructions for these various types of machines. 
     Next, a flow of processes for transmitting emergency information in the SNPN-RAN  41  according to the second example embodiment will be described with reference to  FIG.  5   . First, the MNO radio communication unit  48  of the SNPN-RAN  41  receives SIB information (S 21 ). The MNO radio communication unit  48  receives SIB information including the Primary Notification or SIB information including the Secondary Notification. The SIB information is transmitted by using a carrier frequency. The MNO radio communication unit  48  demodulates a signal transmitted by using the carrier frequency, and outputs SIB information obtained by the demodulation of the signal to the data processing unit  45 . The MNO radio communication unit  48  of the SNPN-RAN  41  may receive SIB information that has been broadcast by using LTE. For example, when the SNPN using 5G is constructed in an area where a 4G service is provided by the MNO but a 5G service is not yet provided, the MNO radio communication unit  48  receives SIB information of 4G. 
     Next, the data processing unit  45  extracts emergency information included in the SIB information (S 22 ). For example, the data processing unit  45  may extract a Warning Type when it receives the SIB information including the Primary Notification. Alternatively, when the data processing unit  45  receives the SIB information including the Secondary Notification, it may extract a Warning message. 
     Next, the SNPN radio communication unit  49  modulates the emergency information extracted by the data processing unit  45 , and transmits the emergency information to the UE  43  by using a local frequency (S 23 ). The SNPN radio communication unit  49  may use a radio frequency of 5G or a radio frequency of 4G as the local frequency. 
     As described above, the SNPN-AMF  42  according to the second example embodiment, like the UE  36 , receives broadcast information distributed from the RAN  31 . Further, the SNPN-AMF  42  transmits the emergency information included in the received broadcast information to the UE  43  by using the local frequency. By doing the above, the UE  43  can receive the emergency information distributed in the MNO  30  via the SNPN-RAN  41  even when the UE  43  cannot communicate with the RAN  31  since it is registered in the SNPN-AMF  42 . 
     Third Example Embodiment 
     Next, a flow of processes for transmitting emergency information according to a third example embodiment will be described with reference to  FIG.  6   . Steps S 31  and S 32  are similar to Steps S 11  and S 12  shown in  FIG.  4   , respectively, and thus descriptions thereof will be omitted. 
     When the SNPN-RAN  41  receives emergency information in Step S 32 , it transmits an emergency information distribution request message to the SNPN-AMF  42  (S 33 ). The emergency information distribution request message includes the emergency information. 
     Next, the SNPN-RAN  41  determines a distribution area of the emergency information and transmits a Write-Replace Warning Request message to the SNPN-RAN  41  deployed in the distribution area (S 34 ).  FIG.  6    shows that the SNPN-AMF  42  transmits the Write-Replace Warning Request message only to the SNPN-RAN  41 . However, when a plurality of SNPN-RAN entities are deployed in the SNPN  40 , the SNPN-AMF  42  may transmit the Write-Replace Warning Request messages to two or more SNPN-RAN entities. For example, the SNPN-AMF  42  may transmit the Write-Replace Warning Request messages to SNPN-RAN entities deployed in an area around the SNPN-RAN  41  that has transmitted an emergency information distribution request message. The area around the SNPN-RAN  41  may be defined as being an area within an R (R is a real number greater than or equal to zero) kilometer radius of the SNPN-RAN  41 , or may be defined based on an address, such as the same town, ward, city, prefecture, or the like as that of the SNPN-RAN  41 . 
     Alternatively, the SNPN-AMF  42  may transmit the Write-Replace Warning Request messages to all the SNPN-RANs  41  in the SNPN  40 . 
     Next, like in the case of Step S 13  shown in  FIG.  4   , the SNPN-RAN  41  transmits the emergency information included in the Write-Replace Warning Request to the UE  43  as broadcast information (S 35 ). The UE  43  transmits the broadcast information to the UE  43  by using a local frequency. 
     As described above, in the processes for transmitting emergency information according to the third example embodiment, the SNPN-RAN  41  receives emergency information and then a plurality of SNPN-RANs in the SNPN  40  transmit the emergency information to the UE via the SNPN-AMF  42 . The SNPN-RAN  41  transmits an emergency information distribution request message to the RAN  31 , whereby even an SNPN-RAN entity which is deployed in the SNPN  40  and is deployed outside the MNO network  30  can receive emergency information that is transmitted through the MNO network  30 . 
     Further, when the SNPN-RAN  41  receives the emergency information in Step S 32 , it may transmit the emergency information to the UE  43  like in the case of the second example embodiment. That is, when the SNPN-RAN  41  receives emergency information from the RAN  31 , it may transmit the emergency information to the UE  43  and also transmit an emergency information distribution request message to the SNPN-AMF  42 . 
     Next, a description will be given of a configuration example of the SNPN-RAN entity  10  and the SNPN-RAN entity  41  (hereinafter collectively referred to as the SNPN-RAN entity  10  and the like) described in the above example embodiments.  FIG.  7    is a block diagram showing a configuration example of the SNPN-RAN entity  10  and the like. As shown in  FIG.  7   , the SNPN-RAN entity  10  and the like include an RF transceiver  1001 , a network interface  1003 , a processor  1004 , and a memory  1005 . The RF transceiver  1001  performs analog RF signal processing to communicate with UEs or RAN entities. The RF transceiver  1001  may include a plurality of transceivers. The RF transceiver  1001  is coupled to an antenna  1002 _ 1 , an antenna  1002 _ 2 , and a processor  1004 . The antenna  1002 _ 1  may be used to communicate with the UEs, and the antenna  1002 _ 2  may be used to communicate with the RAN entities. The RF transceiver  1001  receives modulated symbol data (or OFDM symbol data) from the processor  1004 , generates a transmission RF signal, and supplies the generated transmission RF signal to the antennas  1002 _ 1  and  1002 _ 2 . Further, the RF transceiver  1001  generates a baseband reception signal based on a reception RF signal received by the antennas  1002 _ 1  and  1002 _ 2 , and supplies the generated signal to the processor  1004 . 
     The network interface  1003  is used for communicating with a network node (e.g., other core network nodes). The network interface  1003  may include, for example, a network interface card (NIC) compliant with IEEE 802.3 series. 
     The processor  1004  performs data plane processing and control plane processing including digital baseband signal processing for radio communication. For example, in the case of LTE and 5G, digital baseband signal processing performed by the processor  1004  may include signal processing of a MAC layer and a PHY layer. 
     The processor  1004  may include a plurality of processors. For example, the processor  1004  may include a modem processor (e.g., a DSP) that performs the digital baseband signal processing and a protocol stack processor (e.g., a CPU or an MPU) that performs the control plane processing. 
     The memory  1005  is constituted of a combination of a volatile memory and a non-volatile memory. The memory  1005  may include a plurality of memory devices that are physically independent from each other. The volatile memory is, for example, a Static Random Access Memory (SRAM), a Dynamic RAM (DRAM), or any combination thereof. The non-volatile memory is a Mask Read Only Memory (MROM), an Electrically Erasable Programmable ROM (EEPROM), a flash memory, a hard disk drive, or any combination thereof. The memory  1005  may include a storage located away from the processor  1004 . In this case, the processor  1004  may access the memory  1005  via the network interface  1003  or a not-illustrated I/O interface. 
     The memory  1005  may store software modules (computer programs) including instructions and data to perform the processing by the SNPN-RAN entity  10  and the like described in the above example embodiments. In some implementations, the processor  1004  may load the software modules from the memory  1005  and execute the loaded software modules, thereby performing the processing of the SNPN-RAN entity  10  and the like described in the above example embodiments. 
     It should be noted that the present disclosure is not limited to the above-mentioned example embodiments, and can be modified as appropriate within a range not deviating from the gist. 
     Some or all of the above example embodiments may also be described as the following supplementary notes, but are not limited to the following. 
     (Supplementary Note 1) 
     An SNPN-RAN entity comprising: 
     a reception unit configured to receive, from a base station deployed in a network operated by a communication carrier, emergency information transmitted by using a first frequency used by the communication carrier; and 
     a transmission unit configured to transmit, by using a second frequency used in a Stand-Alone Non-Public Network (SNPN), the emergency information to a communication terminal registered in the SNPN. 
     (Supplementary Note 2) 
     The SNPN-RAN entity according to Supplementary note 1, wherein the reception unit is configured to receive the emergency information included in first SIB information transmitted in the network operated by the communication carrier. 
     (Supplementary Note 3) 
     The SNPN-RAN entity according to Supplementary note 2, further comprising a data processing unit configured to extract the emergency information included in the first SIB information and set the emergency information in second SIB information to be transmitted by using the second frequency, 
     wherein the transmission unit is configured to transmit the second SIB information including the emergency information to the communication terminal registered in the SNPN by using the second frequency. 
     (Supplementary Note 4) 
     The SNPN-RAN entity according to any one of Supplementary notes 1 to 3, wherein the reception unit is configured to receive, as a communication terminal in a limited service state in which it is possible to receive the emergency information transmitted from the base station, the emergency information transmitted from the base station even when the SNPN-RAN entity is not registered in the network operated by the communication carrier. 
     (Supplementary Note 5) 
     The SNPN-RAN entity according to any one of Supplementary notes 1 to 4, wherein the reception unit is configured to receive the emergency information transmitted from the base station as a communication terminal capable of performing communication in the network operated by the communication carrier in a state in which the SNPN-RAN entity is registered in the network operated by the communication carrier. 
     (Supplementary Note 6) 
     The SNPN-RAN entity according to any one of Supplementary notes 1 to 5, wherein the transmission unit is configured to transmit the emergency information to an SNPN core network apparatus deployed in the SNPN, and transmit the emergency information to the communication terminal registered in the SNPN by using the second frequency based on a distribution instruction message of the emergency information received from the SNPN core network apparatus. 
     (Supplementary Note 7) 
     A distribution system comprising: 
     a reception apparatus configured to receive, from a base station deployed in a network operated by a communication carrier, emergency information transmitted by using a first frequency used by the communication carrier; and 
     an SNPN-RAN entity configured to transmit, by using a second frequency used in a Stand-Alone Non-Public Network (SNPN), the emergency information received from the reception apparatus to a communication terminal registered in the SNPN. 
     (Supplementary Note 8) 
     The distribution system according to Supplementary note 7, wherein the reception apparatus is configured to receive the emergency information included in first SIB information transmitted in the network operated by the communication carrier. 
     (Supplementary Note 9) 
     The distribution system according to Supplementary note 8, wherein the SNPN-RAN entity is configured to extract the emergency information included in the first SIB information, set the emergency information in second SIB information to be transmitted by using the second frequency, and transmit the second SIB information including the emergency information to the communication terminal registered in the SNPN by using the second frequency. 
     (Supplementary Note 10) 
     A distribution method comprising: 
     receiving, from a base station deployed in a network operated by a communication carrier, emergency information transmitted by using a first frequency used by the communication carrier; and 
     transmitting, by using a second frequency used in a Stand-Alone Non-Public Network (SNPN), the emergency information to a communication terminal registered in the SNPN. 
     (Supplementary Note 11) 
     A program for causing a computer to: 
     receive, from a base station deployed in a network operated by a communication carrier, emergency information transmitted by using a first frequency used by the communication carrier; and 
     transmit, by using a second frequency used in a Stand-Alone Non-Public Network (SNPN), the emergency information to a communication terminal registered in the SNPN. 
     Although the present disclosure has been described with reference to the example embodiments, the present disclosure is not limited to the above-described example embodiments. Various changes that may be understood by those skilled in the art may be made to the configurations and details of the present disclosure within the scope of the disclosure. 
     This application is based upon and claims the benefit of priority from Japanese patent application No. 2020-76125, filed on Apr. 22, 2020, the disclosure of which is incorporated herein in its entirety by reference. 
     REFERENCE SIGNS LIST 
     
         
           10  SNPN-RAN ENTITY 
           11  RECEPTION UNIT 
           12  TRANSMISSION UNIT 
           30  MNO NETWORK 
           31  RAN 
           32  AMF 
           33  CBCF/PWS-IWF 
           34  CBE 
           35  N3IWF 
           36  UE 
           40  SNPN 
           41  SNPN-RAN 
           42  SNPN-AMF 
           43  UE 
           45  DATA PROCESSING UNIT 
           46  SNPN-RAN CONTROL UNIT 
           47  5GC COMMUNICATION UNIT 
           48  MNO RADIO COMMUNICATION UNIT 
           49  SNPN RADIO COMMUNICATION UNIT