Information communication system, user terminal device, and information communication method

Abstract

This information communication system comprises a user terminal device, at least two base stations, and a network device. The user terminal device transmits a dual network registration request for the user terminal device to connect to the one network device via a plurality of the base stations on the basis of a single subscriber identifier, and a network registration request including a dual network registration identifier that is information for identifying a plurality of network registration requests on the basis of the single subscriber identifier. When receiving the dual network registration request from the user terminal device, the network device manages a connection for each dual network registration identifier even if the subscriber identifier is the same.

Description

Information communication system, user terminal device, and information communication method

[0001] The present invention relates to an information communication system, a user terminal device, and an information communication method. The present application claims priority based on Japanese Patent Application No. 2025-051321 filed in Japan on March 26, 2025, the content of which is incorporated herein by reference.

[0002] Conventionally, there have been communication systems using devices and network devices. For example, Non-Patent Document 1 defines the standard specifications of 3GPP (registered trademark).

[0003] 3GPP TS 23.501 V18.2.0, “3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System architecture for the 5G System (5GS); Stage 2 (Release 18)”

[0004] Here, when considering a communication mode (Dual Steering) in which UE (User Equipment) is connected to two 3GPP access networks simultaneously with a single subscriber identifier and terminates at one UPF (User Plane Function) of a mobile core, the current 3GPP (registered trademark) standard specifications have the following problems: there is no mechanism for appropriately performing multiple Registrations to the same mobile core network with one piece of subscriber information, and it is inefficient because the two 3GPP access networks need to exchange the same information with each other.

[0005] The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide an information communication system, a user terminal device, and an information communication method capable of appropriately implementing Dual Steering.

[0006] (A1) One aspect of the present invention is an information communication system comprising a user terminal device, at least two base stations, and a network device, wherein the user terminal device transmits a dual network registration request requesting that the user terminal device connect to one network device via a plurality of base stations based on a single subscriber identifier, and a network registration request including a dual network registration identifier which is information for identifying a plurality of network registration requests based on a single subscriber identifier, and when the network device receives the dual network registration request from the user terminal device, it manages connections for each dual network registration identifier, even if the subscriber identifier is the same.

[0007] (A2) In another aspect of the present invention, in the information communication system described in (A1) above, the wireless access network provided by the multiple base stations does not communicate directly with each other.

[0008] (A3) In another aspect of the present invention, in the information communication system described in (A1) or (A2) above, the dual network registration request includes information identifying a plurality of base stations to which the user terminal device wishes to connect.

[0009] (A4) In another aspect of the present invention, in any of the information communication systems described in (A1) to (A3) above, the user terminal device transmits the subscriber identifier and the dual network registration request at different timings.

[0010] (A5) In another aspect of the present invention, in any of the information communication systems described in (A1) to (A4) above, the user terminal device transmits the dual network registration request as information that extends the subscriber identifier.

[0011] (A6) In another aspect of the present invention, in any of the information communication systems described in (A1) to (A5) above, the dual network registration identifier is GUTI (Global Unique Temporary Identity).

[0012] (A7) Another aspect of the present invention is a user terminal device comprising at least a processor and memory, which communicates information with one network device via at least two base stations, and which transmits a dual network registration request that requests to connect to one network device via a plurality of base stations based on a single subscriber identifier, and a network registration request that includes a dual network registration identifier which is information for identifying a plurality of network registration requests based on a single subscriber identifier.

[0013] (A8) Another aspect of the present invention is an information communication method using a user terminal device, at least two base stations, and a network device, the method comprising: the user terminal device transmitting a dual network registration request requesting that the user terminal device connect to one network device via a plurality of base stations based on a single subscriber identifier, and a network registration request including a dual network registration identifier which is information for identifying a plurality of network registration requests based on a single subscriber identifier; and the network device, upon receiving the dual network registration request from the user terminal device, managing connections for each dual network registration identifier, even if the subscriber identifier is the same.

[0014] (B1) One aspect of the present invention is an information communication system comprising a user terminal device, at least two base stations, and a network device, wherein the user terminal device transmits a dual network registration request requesting that the user terminal device connect to one network device via a plurality of base stations based on a single subscriber identifier, and a network registration request including a dual network registration identifier which is information for identifying a plurality of network registration requests based on a single subscriber identifier, and the network device stores information when it obtains information from the user terminal device via the first base station, and in information communication via the second base station, it omits information communication with the user terminal device by referring to the information stored through the information communication via the first base station.

[0015] (B2) In addition, in the information communication system described in (B1) above, the network device stores information based on a single subscriber identifier through information communication via the first base station, thereby omitting the acquisition of information based on the subscriber identifier in information communication via the second base station.

[0016] (B3) In addition, in the information communication system described in (B1) or (B2) above, when the network device authenticates the user terminal device via information communication through the first base station, it stores the authentication result and, in information communication through the second base station, it refers to the stored authentication result to omit the authentication process again.

[0017] (B4) In addition, in one aspect of the present invention, in any of the information communication systems described in (B1) to (B3) above, the network device stores the information when it acquires it via the first base station, and further stores the time when the information was stored. In information communication via the second base station, if the difference between the time the information was stored and the current time is less than or equal to a predetermined difference, the network device omits information communication with the user terminal device by referring to the information stored via the information communication via the first base station.

[0018] (B5) In addition, in the information communication system described in (B4) above, if the difference between the time the information was stored and the current time is greater than a predetermined difference, the network device does not refer to the information stored via the first base station, but instead performs information communication with the user terminal device again.

[0019] (B6) Another aspect of the present invention is an information communication method using a user terminal device, at least two base stations, and a network device, the network device comprising at least a processor and memory, and communicating information with one user terminal device via at least two base stations, the network device receiving from the user terminal device a dual network registration request requesting the user terminal device to connect to the network device via a plurality of base stations based on a single subscriber identifier, and a network registration request including a dual network registration identifier which is information for identifying a plurality of network registration requests based on a single subscriber identifier, and storing information when information is obtained from the user terminal device via the first base station, and in information communication via the second base station, the network device omits information communication with the user terminal device by referring to the information stored through the information communication via the first base station.

[0020] (B7) Another aspect of the present invention is an information communication method using a user terminal device, at least two base stations, and a network device, the method comprising: the steps of: the user terminal device transmitting a dual network registration request requesting that the user terminal device connect to one network device via a plurality of base stations based on a single subscriber identifier, and a network registration request including a dual network registration identifier which is information for identifying a plurality of network registration requests based on a single subscriber identifier; and the steps of the network device storing information when it obtains information from the user terminal device via a first base station, and omitting information communication with the user terminal device in information communication via a second base station by referring to the information stored through information communication via the first base station.

[0021] According to the present invention, it is possible to provide an information communication system, a user terminal device, and an information communication method that can suitably implement Dual Steering.

[0022] This is a diagram illustrating the outline of the information communication system according to this embodiment. This is a diagram illustrating the network configuration of the information communication system according to this embodiment. This is a diagram illustrating a series of steps in the information communication method according to this embodiment. This is a diagram showing an example of information included in the dual network registration context managed by the network device according to this embodiment. This is a block diagram showing an example of the user terminal device and the internal configuration of the network device according to this embodiment.

[0023] [Embodiments] Preferred embodiments of an information communication system, user terminal device, network device, and information communication method according to an aspect of the present invention will be described in detail below with reference to the attached drawings. Note that the aspects of the present invention are not limited to these embodiments, and include various modifications or improvements. In other words, the components described below include those that are easily conceivable by those skilled in the art, and those that are substantially the same, and the components described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of components can be made without departing from the spirit of the present invention. Also, in the following drawings, the scale and number of components in each structure may differ from the scale and number of components in the actual structure in order to make each structure easier to understand.

[0024] First, the prerequisites for this embodiment will be described. The information communication system, user terminal device, network device, and information communication method according to this embodiment implement Dual Steering. Hereinafter, Dual Steering refers to a communication method in which a UE (User Equipment) connects to two 3GPP® access networks accommodated in the same mobile core network simultaneously with two RANs (or simply ANs) using a single subscriber identifier (single SIM), establishes sessions, and integrates them in the mobile core. Dual Steering may also be simply referred to as Dual Steer.

[0025] The following description assumes that in Dual Steering, the UE passes through two RANs (or simply ANs). However, this embodiment is not limited to this example, and may terminate at the same mobile core network via three RANs (or simply ANs).

[0026] Furthermore, the following explanation assumes that in Dual Steering, the two RANs (or simply ANs) to which the UE is connected do not signal to each other. Therefore, the two RANs (or simply ANs) may be of different generations of communication standards, from different vendors, or even have no interface established between them.

[0027] To implement Dual Steering, it is necessary to establish a session in each RAN (or simply AN) and maintain that connection even when the UE moves. To achieve this, it is necessary to perform processing equivalent to registration in 5G for each access. Furthermore, it is necessary to establish and update the user context between the UE, RAN, and mobile core network (managing the connected base station and AMF information), and to establish a security context between the UE and RAN. Hereafter, performing multiple registrations to the same mobile core network with a single subscriber identifier (single SIM) will be referred to as Dual Registration. Dual Registration may also be simply referred to as DualReg.

[0028] Here, when attempting to implement Dual Registration, there was a problem in that the current 3GPP (registered trademark) system does not have the means to realize such Dual Registration. Therefore, if a terminal simply sends two network registration requests via different RANs using the conventional mechanism, it is conceivable that the network registration information will be overwritten, as the second request will be treated as the latest network registration request. This problem arises because the user identifier and Request Type do not change in each of the two network registration requests.

[0029] Furthermore, if you attempt to implement Dual Registration, the conventional paging procedure is as follows (1) to (4). (1) UPF determines that no session exists corresponding to the DL traffic. (2) UPF notifies SMF via N4 session (it is assumed that the UPF and SMF accommodating a UE's DS session are the same. In other words, it is assumed that there is only one N4 session associated with DS session traffic.) (3) SMF derives the PDU Session ID and its associated AMF information from the N4 Session ID and notifies the AMF of the Session ID. (4) AMF uses the PDU Session ID to check the status of the associated access (if it is CM-IDLE, it performs paging; if it is CM-CONNECTED, it performs step 4 or later of the service request (after AMF)).

[0030] If a DS session is operated under a single PDU Session ID, and there are two accesses associated with that PDU Session ID, the AMF has no way of determining which access should perform the subsequent processing. Since the AMF cannot determine which access should perform the subsequent processing, it is expected that paging will be applied to both accesses each time. However, this is expected to lead to problems such as inefficient bandwidth consumption and power consumption for processing. For example, in phases where 6G coverage is very narrow, it may be better to postpone paging to 6G.

[0031] Furthermore, if we were to attempt to implement Dual Registration individually for each access from the UE to the RAN, it is anticipated that authentication processes between the user and the network, as well as security context establishment processes between the UE and the RAN, would be duplicated, leading to inefficiencies.

[0032] In this embodiment, the above-mentioned problems are solved, and dual steering is preferably implemented.

[0033] [Information and Communication System] Figure 1 is a diagram illustrating the outline of the information and communication system according to this embodiment. First, the outline of the information and communication system 1 will be described with reference to the figure. The information and communication system 1 comprises a user terminal device 10, at least two base stations 20, and a network device 30. The information and communication system 1 may be configured to include multiple user terminal devices 10, base stations 20, and network devices 30, but the figure only shows the minimum configuration necessary to realize the information and communication system 1.

[0034] The user terminal device 10 establishes a session with each of the two base stations 20 included in the information communication system 1 based on a single subscriber identifier. The subscriber identifier may specifically be IMSI (International Mobile Subscriber Identity), ICCID, or IMEI. The user terminal device 10 transmits a dual network registration request and a network registration request.

[0035] A dual network registration request is a request for a user terminal device 10 to connect to a single network device 30 via multiple base stations 20 based on a single subscriber identifier. Preferably, the dual network registration request includes information identifying the base station 20 that the user terminal device 10 wishes to connect to. When attempting to perform Dual Registration, the user terminal device 10 connects to multiple base stations 20, so preferably, the dual network registration request includes information identifying the multiple base stations 20 that the user terminal device 10 wishes to connect to.

[0036] A network registration request is a request that includes a dual network registration identifier. The dual network registration identifier is information for identifying multiple network registration requests based on a single subscriber identifier. Here, the user terminal device 10 may transmit the subscriber identifier and the network registration request as different information and at different timings. Alternatively, the user terminal device 10 may transmit the dual network registration request as information that extends the subscriber identifier. Specifically, when using SUCI as the subscriber identifier, for example, one bit may be added to the SUCI information and used as a flag indicating the presence or absence of a network registration request.

[0037] Base station 20 provides the functionality of a radio access network (RAN). Specifically, base station 20 provides the functionality of a 3GPP® access network. The figure shows base station 20-1 and base station 20-2 as examples of multiple base stations 20. Base stations 20-1 and base station 20-2 do not signal to each other. In other words, the radio access networks provided by multiple base stations 20 do not communicate directly with each other. That is, base stations 20-1 and base station 20-2 may have different generations of communication standards, may be provided by different vendors, and may not have an interface between their RANs.

[0038] The network device 30 provides the functions of the mobile core network. The network device 30 includes at least the function of UPF (User Plane Function). UPF enforces QoS rules for user packets (U-Planes) and processes the transmission and reception of user packets to and from the data network (DN). When the network device 30 receives a dual network registration request from the user terminal device 10, it manages connections for each dual network registration identifier, even if the subscriber identifier is the same.

[0039] Figure 2 is a diagram illustrating the network configuration of the information and communication system according to this embodiment. The network configuration of the information and communication system 1 will be explained in more detail with reference to this figure.

[0040] As shown in the figure, the network device 30 includes a C-Plane (Control-Plane) and a GW. The GW refers to the gateway device of the mobile core network. The GW is a node that serves as the connection point between the data network (DN) and the mobile core network. In 5G, the GW may be a UPF, and in 4G, the GW may be a PGW (Packet Data Network Gateway) or an SPGW (Packet Switch Gateway).

[0041] [Information Communication Method] Figure 3 is a diagram illustrating the sequence of steps in the information communication method according to this embodiment. The sequence of steps in the information communication method in the information communication system 1 described above will be explained with reference to this figure.

[0042] (Step S11) The user terminal device 10 makes a Registration Request to the network device 30. The network registration request includes the subscriber identifier as well as the following information (1) to (4): (1) Dual network registration instruction information (DualReg indication) (2) Information indicating that the terminal is requesting dual network registration (3) Dual network registration identifier (DualReg ID) (4) Information for the network device 30 and the user terminal device 10 to identify multiple network registrations associated with a single subscriber identifier

[0043] (Step S12) Upon receiving the request in step S11, the network device 30 performs the following operations (1) to (3). Note that the request in step S11 is received by a mobile core network (e.g., AMF in 5G) that oversees network registration processing within the network device 30. (1) First, the network device 30 determines, based on the DualReg indication in the Registration Request (network registration request), that the current network registration request requests DualReg. (2) When a DualReg request is determined, the network device 30 creates a user context that supports DualReg (an example of a method for creating a user context will be described later with reference to FIG. 4). (3) The DualReg-compatible context manages, for a single piece of Subscription Permanent Identifier (SUPI) information, a plurality of network registration identifiers (DualReg ID) and 3GPP (registered trademark) access network information associated therewith.

[0044] (Step S13) Next, the network device 30 returns a Registration Accept to the user terminal device 10. The Registration Accept includes the aforementioned network registration identifier (DualReg ID).

[0045] [Network Registration Processing] Hereinafter, the network registration processing for DualSteering will be described in detail. Note that conventional Registration is configured from step 1 to step 25, as described in the aforementioned Non-Patent Document 1 (3GPP TS 23.501 V18ten2.0). Hereinafter, description will be given focusing on differences between the conventional processing and the processing according to the present embodiment.

[0046] [Processing when Implementing Dual Reg in a First Access Network] First, an example of processing when implementing Dual Registration in a first access network will be described.

[0047] (Step 1) In this step, the user terminal device 10 transmits a network registration request to the base station 20. At this time, the user terminal device 10 includes parameters of dual network registration indication information (Dual Registration Indication) and a dual NW registration identifier (Dual Registration Identifier) in an information container for a mobile core (Registration Request in 5G).

[0048] The dual network registration indication information indicates that the NW registration request requires Dual Registration. Dual Registration refers to performing two NW registration processes on the same core network with a single subscriber identifier (single SIM). This may be implemented, for example, as a new entry (e.g., Request Type = Dual Registration) in "Request Type", which is one of the IEs defined in the existing Registration procedure.

[0049] The dual network registration identifier is information used to uniquely identify each NW registration between the terminal and the mobile core when the terminal performs two network registrations with a single subscriber identifier. Here, the dual network registration identifiers associated with the same subscriber identifier necessarily take different values. As a specific value, a character string may be set such as "DualRegID=primary / secondary", or a numerical value may be set such as "DualRegID=1, 2, ...". Alternatively, a temporary user identifier (Global Unique Temporary Identity; GUTI) may be used as the dual network registration identifier.

[0050] The temporary user identifier (GUTI) is a temporary identifier used for signaling instead of the SUPI to ensure the confidentiality of the user identifier. The GUTI is issued from the network, and the user terminal device 10 usually caches and stores the value from the previous connection. However, there may be cases where the user terminal device 10 does not have a temporary user identifier, such as during initial network registration. In this case, the dual network registration identifier may be determined by other means.

[0051] As an alternative, specifically, it is conceivable to use a dual network registration identifier other than GUTI until a GUTI with a different value is issued. Furthermore, the RAN information container (AN message in 5G) may include dual network registration instruction information and GUAMI (Globally Unique AMF Identifier) ​​as parameters.

[0052] The dual network registration instruction information indicates to the RAN node that this network registration request is requesting Dual Registration. By including the dual network registration instruction information as a parameter in the RAN information container, it is possible to prevent the RAN from selecting an AMF that does not support DualReg, which could result in the request being rejected or its completion being delayed.

[0053] GUAMI is an AMF identifier. Typically, the identifier from the previous connection is used.

[0054] (Step 2 and Step 3) In these steps, the base station 20 sends a message to the network device 30. The message includes a Dual Registration indication. If the information sent from the user terminal device 10 does not include GUAMI, the base station 20 selects a network device 30 (specifically, AMF) that supports Dual Registration and forwards the request. If the message includes both a Dual Registration indication and GUAMI, the base station 20 checks whether the network device 30 (specifically, AMF) indicated by GUAMI supports DualReg. If it does, the base station 20 forwards the request to the network device 30 (specifically, AMF) specified by GUAMI. If Dual Registration is not supported, select a network device 30 (specifically, an AMF) that supports Dual Registration and forward the request.

[0055] (Steps 4 to 8) Details are omitted as they are the same as before. Note that if the network registration request includes a GUI, the network device 30 may use the GUI to identify the old network device 30 (Old AMF) to which the user terminal device 10 was connected at the time of connection, and request the past UE context. Also, if authentication is required, SUCI may be used to select AUSF.

[0056] (Step 9) In this step, an authentication process is performed. The authentication process may be carried out in the conventional manner, or, as will be described later, one of the authentications with the two base stations 20 may be reused.

[0057] (Step 14) The AMF receives the user's subscription data from the UDM. If the user context has not been obtained from the Old AMF, the AMF then creates a user context. At this time, if dual network registration instruction information was received in Step 3 as described above, the AMF creates a context for Dual Registration (DualReg context). Preferably, the context for Dual Registration includes information on Dual Registration Identifier and Paging Priority.

[0058] Additionally, the context for Dual Registration includes, for each Dual Registration Identifier, Paging priority, GUTI, Access Type, AMF UE NGAP ID, RAN UE NGAP ID, Registration Area, TAI of last Registration, Network Slice Instance(s), Security Information forward CP, Security Information forward UP, Mobility Restrictions, Events Subscription, and UE Radio. It is preferable to manage some or all of the information in Capability Information, DRX Parameters, Clock Quality Detail Level, and PDU Session Level Context. Other information included in the context for Dual Registration can be anything, such as that included in the context of the previous specification.

[0059] [Dual Network Registration Context] Figure 4 shows an example of a dual network registration context managed by the network device according to this embodiment. The figure shows an example of the information included in the dual network registration context. The figure shows each field and a description of that field.

[0060] Paging Priority is shown in two places in the diagram, but it is sufficient if it is included in either format (Note 1). Paging Priority is information indicating the priority of paging (or NW-triggered Service Request). Paging Priority includes information that can identify the access with higher priority. For example, examples of information used as Paging Priority include dual network registration identifiers such as GUTI, or PDU Session ID. In addition, equal priority may be set between two accesses. For example, if two dual network registration entries are included, the priority may be set to be equal, or a value indicating equal priority may be provided. This function prevents the inefficient operation of always activating both accesses.

[0061] Each Dual Registration Identifier level context: The following shows the information contained in each Dual Registration Identifier.

[0062] The Dual Registration Identifier is an identifier transmitted from the user terminal device 10. Alternatively, the Dual Registration Identifier may be a temporary identifier of the terminal assigned by the AMF.

[0063] GUI is a temporary identifier for a terminal. When GUI is used in a Dual Registration Identifier, it is not necessary to include a separate GUI for each Dual Registration Identifier (Note 2). Also, if the same GUI is used in two Registrations, it does not need to be included in Each Dual Registration Identifier level context (because it is managed as information associated with SUPI, with one GUI per context).

[0064] If information about Paging Priority is included for each Dual Registration Identifier, for example, the one with the higher Paging Priority number may be considered to have higher priority, and paging may be performed in the session associated with the GUI of the higher priority. It is also conceivable that if paging fails, it may be performed on the access of the lower priority user. If the same value is set for both GUIs, it is conceivable that paging may be performed on both.

[0065] The AMF UE NGAP ID is information that AMF uses to uniquely identify which RAN a registration identified by the Dual Registration Identifier is connected to. The following explanation is the same as before, so it will be omitted.

[0066] (Step 21) The AMF assigns a new temporary user identifier (GUI) to the user terminal device 10. If a Dual Registration indication was included in Step 1 described above, the AMF may perform a process such that two GUIs associated with the same user terminal device 10 have different values. However, if the GUI is not used as a dual network registration identifier, the GUIs may have the same value.

[0067] As an example of deriving different GUITS, firstly, an internal counter can be maintained for each SUPI, incremented for each registration, and used as part of the GUITS. Secondly, after deriving candidate GUITS values ​​by performing random bit assignment or hash calculation, the GUITS of other registrations associated with the same SUPI can be checked, and if a duplicate occurs, recalculation can be performed. This process is repeated until there are no more duplicates. The AMF responds to the user terminal device 10 with a Registration Accept message containing the newly determined GUITS.

[0068] (Steps 22 to 25) Details are omitted as they are the same as before.

[0069] [Processing when performing Dual Reg on the second access network] Next, we will explain an example of the process when performing Dual Registration on the second access network. Basically, it is the same as the [Processing when performing Dual Reg on the first access network] described above. The differences in the [Processing when performing Dual Reg on the second access network] will be explained below.

[0070] (Step 1) In this embodiment, the information container for RAN includes the Dual Registration indication, and at the same time includes the GUAMI (AMF identifier) ​​obtained in the first Reg, rather than the GUAMI from the previous Dual Reg execution.

[0071] (Step 2) The base station 20 determines the AMF based on the transmitted GUAMI. This ensures that the AMF selected for each Reg is always the same when Dual Registration is performed.

[0072] (Step 9 and beyond) The process from here onwards remains the same as before, so we will omit further details.

[0073] [Authentication Process] Next, we will explain the authentication process. The authentication process corresponds to Step 9 described above.

[0074] [Processing when performing Dual Reg on the first access network] First, the AMF sends an authentication request to the selected AUSF. This request includes a Dual Registration indication. The AUSF sends an authentication data request to the UDM, including the SUPI (SUCI). The UDM responds to the AUSF with the authentication information (authentication voidor) associated with the SUPI. Here, if the AUSF's request from the AMF included a Dual Registration indication, it saves the received "authentication information" and / or "authentication result". The AUSF may also send the "authentication information" and / or "authentication result" to the AMF. The AMF may save this information.

[0075] [Processing when performing Dual Reg on the second access network] Next, we will explain an example of the process when performing Dual Registration on the second access network. Here, when performing Dual Reg on the second access network, it is assumed that the processing on the first access network as described above has been performed.

[0076] When Dual Reg is performed on the second access network, if the AUSF has cached authentication data, the signaling for obtaining authentication data between the AUSF and the UDM can be skipped. In this case, the AUSF may use the cached information (authentication voidor) for the authentication process. In this embodiment, the network device 30 stores information when it obtains information from the user terminal device 10 via the first base station 20, and in information communication via the second base station 20, it can refer to the information stored through the information communication via the first base station 20, thereby omitting information communication with the user terminal device 10.

[0077] Specifically, the information to be omitted may be information based on the subscriber identifier. Furthermore, the information to be omitted may also be information related to authentication. In other words, in this embodiment, if the user terminal device 10 has already been authenticated via the first base station 20, it is possible to efficiently and securely communicate information without performing authentication again for the same user terminal device 10 based on the same subscriber identifier (by reusing the already completed authentication result).

[0078] The retention period for authentication information and authentication results may be until the AUSF / AMF node is reset, or the retention period may be managed using a timer or the like. The AUSF triggers an authentication challenge procedure, and authentication processing is performed between the AUSF, AMF, RAN, and UE, completing user and network authentication. By setting a retention period, it is possible to deter the continued reuse of authentication results indefinitely and realize highly secure information communication. In this case, when the network device 30 acquires information via the first base station 20, it saves the information and also saves the time the information was saved. In information communication via the second base station 20, if the difference between the time the information was saved and the current time is less than or equal to a predetermined difference, it can refer to the information saved via information communication via the first base station 20, thereby omitting information communication with the user terminal device 10. Furthermore, if the difference between the time the information was saved and the current time is greater than a predetermined difference, the network device 30 may choose not to refer to the information saved via information communication through the first base station 20, and instead perform information communication with the user terminal device 10 again.

[0079] By performing this process, processing time can be reduced. Furthermore, if the AMF determines that user authentication is unnecessary, it may skip user authentication and only perform the security context establishment process between the UE and the access network. An example of such a determination is when the cached "authentication result" is a value indicating successful authentication.

[0080] [Internal Configuration] Figure 5 is a block diagram showing an example of the internal configuration of a user terminal device and a network device according to this embodiment. At least some of the functions of the user terminal device 10 and the network device 30 can be realized using a computer. As shown in the figure, the computer is composed of a central processing unit 901, RAM 902, input / output ports 903, input / output devices 904 and 905, etc., and a bus 906. The computer itself can be realized using existing technology. The central processing unit 901 executes instructions contained in programs read from RAM 902, etc. The central processing unit 901 writes data to RAM 902, reads data from RAM 902, and performs arithmetic and logical operations according to each instruction. RAM 902 stores data and programs. Each element included in RAM 902 has an address and can be accessed using that address. RAM is an abbreviation for "Random Access Memory". Input / output ports 903 are ports for the central processing unit 901 to exchange data with external input / output devices, etc. Input / output devices 904 and 905 are input / output devices. Input / output devices 904 and 905 exchange data with the central processing unit 901 via input / output port 903. Bus 906 is a common communication channel used inside the computer. For example, the central processing unit 901 reads and writes data to RAM 902 via bus 906. Also, for example, the central processing unit 901 accesses input / output ports via bus 906. Furthermore, all or part of the functional units of the user terminal device 10 and the network device 30 may be implemented using hardware such as ASIC, PLD, or FPGA. Furthermore, all or part of the functional units may be implemented by a combination of software and hardware.

[0081] [Summary of Embodiments] According to the embodiments described above, the information communication system 1 comprises a user terminal device 10, at least two base stations 20, and a network device 30. The user terminal device 10 transmits a dual network registration request requesting that the user terminal device 10 connect to one network device 30 via multiple base stations 20 based on a single subscriber identifier, and a network registration request that includes a dual network registration identifier, which is information for identifying multiple network registration requests based on a single subscriber identifier. When the network device 30 receives a dual network registration request from the user terminal device 10, it manages the connection for each dual network registration identifier, even if the subscriber identifier is the same. By adopting such a configuration, the current 3GPP (registered trademark) system does not have means to realize such Dual Registration, and problems such as overwriting network registration information by treating the second request as the latest network registration request when a UE transmits two network registration requests via different RANs do not occur, making it possible to suitably implement Dual Steering.

[0082] Furthermore, according to the above-described embodiment, in the information communication system 1, the wireless access network provided by the multiple base stations 20 does not communicate directly with each other. According to this embodiment, when the network device 30 receives a dual network registration request from the user terminal device 10, even if the subscriber identifier is the same, it manages the connection for each dual network registration identifier, thereby enabling suitable Dual Steering even if the multiple base stations 20 do not communicate directly with each other.

[0083] Furthermore, according to the embodiment described above, the dual network registration request includes information identifying multiple base stations 20 that the user terminal device 10 wishes to connect to. By adopting such a configuration, it becomes possible to identify the base stations 20 and suitably perform Dual Steering.

[0084] Furthermore, according to the embodiment described above, the subscriber identifier and the request to perform Dual Steering are transmitted as different pieces of information. In other words, the user terminal device 10 transmits the subscriber identifier and the dual network registration request at different times. By transmitting the dual network registration request in this way, Dual Steering can be suitably implemented.

[0085] Furthermore, according to the embodiment described above, the dual network registration request is information that extends the subscriber identifier. For example, SUPI or SUCI may be extended by one bit, and the extended bit may be used as a flag indicating whether or not to make a dual network registration request. By adopting such a configuration, Dual Steering can be suitably implemented without making major changes.

[0086] Furthermore, according to the embodiment described above, the dual network registration identifier is GUTI (Global Unique Temporary Identity). Note that since GUTI is not issued during the initial communication, it is preferable to use other means. According to this embodiment, by using GUTI as the dual network registration identifier, it is possible to suitably implement Dual Steering without making major changes.

[0087] Furthermore, according to the embodiment described above, the information communication system 1 comprises a user terminal device 10, at least two base stations 20, and a network device 30. The user terminal device 10 transmits a dual network registration request, which requests that the user terminal device 10 connect to one network device 30 via multiple base stations 20 based on a single subscriber identifier, and a network registration request that includes a dual network registration identifier, which is information for identifying multiple network registration requests based on a single subscriber identifier. When the network device 30 obtains information from the user terminal device 10 via the first base station 20, it stores the information, and in information communication via the second base station 20, it omits information communication with the user terminal device 10 by referring to the information stored through information communication via the first base station 20. By adopting such a configuration, duplication of authentication processing between the user and the network, and security context establishment processing between the UE and RAN can be suppressed, and efficient information communication can be performed. Therefore, according to this embodiment, Dual Steering can be suitably implemented.

[0088] Furthermore, according to the embodiment described above, the network device 30 stores information based on a single subscriber identifier through information communication via the first base station 20, thereby omitting the acquisition of information based on the same subscriber identifier in information communication via the second base station 20. Here, it may be unnecessary to acquire information based on the same subscriber identifier through different base stations 20. According to this embodiment, it is possible to suppress the duplicate acquisition of unnecessary information and perform efficient information communication. Therefore, according to this embodiment, Dual Steering can be suitably implemented.

[0089] Furthermore, according to the embodiment described above, when the network device 30 authenticates the user terminal device 10 through information communication via the first base station 20, it stores the authentication result, and in information communication via the second base station 20, it refers to the stored authentication result, thereby omitting the authentication process again. According to this embodiment, it is possible to suppress the duplication of unnecessary authentication and to perform information communication efficiently. Therefore, according to this embodiment, Dual Steering can be suitably implemented.

[0090] Furthermore, according to the embodiment described above, when the network device 30 acquires information via the first base station 20, it stores the information and also stores the time when the information was stored. In information communication via the second base station 20, if the difference between the time the information was stored and the current time is less than or equal to a predetermined difference, the information stored via information communication via the first base station 20 is referenced, thereby omitting information communication with the user terminal device 10. In other words, according to this embodiment, information can be reused while ensuring security within a predetermined time, thus preventing the repeated acquisition of unnecessary information during periods considered safe. Therefore, according to this embodiment, efficient information communication can be performed. Thus, according to this embodiment, Dual Steering can be suitably implemented.

[0091] Furthermore, according to the embodiment described above, if the difference between the time the information was stored and the current time is greater than a predetermined difference, the network device 30 does not refer to the information stored via information communication through the first base station 20, but instead performs information communication with the user terminal device 10 again. According to this embodiment, if a predetermined time has passed, it is difficult to reuse the information while ensuring security, so after a period considered safe has elapsed, even if there is information that can be reused, the information is acquired again. Therefore, according to this embodiment, highly secure information communication can be performed. Thus, according to this embodiment, Dual Steering can be suitably implemented.

[0092] Furthermore, the above-described embodiment makes it possible to "suitably implement Dual Steering," thereby contributing to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), "Build resilient infrastructure, promote sustainable industrialization and expand innovation."

[0093] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and design modifications and the like are also included within the scope of the gist of the present invention.

[0094] Alternatively, computer programs for realizing the functions of each of the above-mentioned devices may be recorded on a computer-readable recording medium, and the programs recorded on this recording medium may be loaded into a computer system and executed. The term "computer system" here may include hardware such as an operating system and peripheral devices. Furthermore, "computer-readable recording medium" refers to writable non-volatile memory such as flexible disks, magneto-optical disks, ROMs, and flash memory, portable media such as DVDs (Digital Versatile Discs), and storage devices such as hard disks built into a computer system.

[0095] Furthermore, "computer-readable recording media" includes volatile memory (e.g., DRAM (Dynamic Random Access Memory)) within a computer system that acts as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, which retains the program for a certain period of time. In addition, the above program may be transmitted from the computer system that stores the program in a storage device, etc., to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" for transmitting the program refers to a medium that has the function of transmitting information, such as a network such as the Internet or a communication line such as a telephone line. Furthermore, the above program may be for the purpose of realizing a part of the above-mentioned functions. Moreover, it may be a so-called differential file (differential program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0096] According to the present invention, dual steering can be suitably implemented.

[0097] 1... Information and communication system, 10... User terminal device, 20... Base station, 30... Network device

Claims

1. An information communication system comprising a user terminal device, at least two base stations, and a network device, wherein the user terminal device transmits a dual network registration request requesting that the user terminal device connect to one network device via a plurality of base stations based on a single subscriber identifier, and a network registration request including a dual network registration identifier which is information for identifying a plurality of network registration requests based on a single subscriber identifier, and when the network device receives the dual network registration request from the user terminal device, manages connections for each dual network registration identifier, even if the subscriber identifier is the same.

2. The information communication system according to claim 1, wherein the wireless access network provided by the multiple base stations does not communicate directly with one another.

3. The information communication system according to claim 1 or 2, wherein the dual network registration request includes information identifying a plurality of base stations to which the user terminal device wishes to connect.

4. The information communication system according to claim 1 or 2, wherein the user terminal device transmits the subscriber identifier and the dual network registration request at different times.

5. The information communication system according to claim 1 or 2, wherein the user terminal device transmits the dual network registration request as information that extends the subscriber identifier.

6. The information communication system according to claim 1 or claim 2, wherein the dual network registration identifier is GUTI (Global Unique Temporary Identity).

7. A user terminal device comprising at least a processor and memory, which communicates information with one network device via at least two base stations, and which transmits a dual network registration request requesting to connect to one network device via a plurality of base stations based on a single subscriber identifier, and a network registration request including a dual network registration identifier which is information for identifying a plurality of network registration requests based on a single subscriber identifier.

8. An information communication method using a user terminal device, at least two base stations, and a network device, comprising: the steps of: the user terminal device transmitting a dual network registration request requesting that the user terminal device connect to one network device via a plurality of base stations based on a single subscriber identifier, and a network registration request including a dual network registration identifier which is information for identifying a plurality of network registration requests based on a single subscriber identifier; and the steps of the network device, upon receiving the dual network registration request from the user terminal device, managing connections for each dual network registration identifier, even if the subscriber identifier is the same.

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