Network device, communication method, and computer program

Abstract

In the present invention, communication device configuration information indicates: a first configuration in which a communication device can perform communication using a plurality of radio access networks simultaneously; a second configuration in which the communication device can perform communication using one of the plurality of radio access networks; or both the first configuration and the second configuration. A network device according to the present invention comprises a policy information provision unit that provides policy information indicating a method used by a target communication device to selectively use the plurality of radio access networks. The policy information provision unit determines the policy information pertaining to the target communication device on the basis of the communication device configuration information.

Description

Network device, communication method and computer program

[0001] This application claims priority to Japanese Patent Application No. 2024-119434, filed on July 25, 2024, the contents of which are incorporated herein by reference.

[0002] Conventionally, a fifth-generation mobile communication system (5G system) standardized by "3GPP (registered trademark) (3rd Generation Partnership Project)" has been known (see, for example, Non-Patent Documents 1 and 2). FIG. 3 is a diagram showing a schematic architecture of a 5G system. In FIG. 3, the 5G system is composed of a UE (User Equipment), a RAN (Radio Access Network), a UPF (User Plane Function) of a CN (Core Network), and various NFs (Network Functions) of the CN control plane (C-plane). Examples of NFs of the CN C-plane include an AMF (Access and Mobility Management Function), an SMF (Session Management Function), a PCF (Policy Control Function), a UDM (Unified Data Management), and a UDR (Unified Data Repository).

[0003] Here, a logical communication path established between a UE and a CN (UPF) to use a mobile communication service is referred to as a "session." A session established between a UE and a CN (UPF) using multiple wireless paths is referred to as a "multi-access session." Non-patent documents 1 and 2 specify a "Multi-access PDU (Packet Data Unit) Session (hereinafter referred to as an "MA PDU Session")" as an example of a multi-access session. A UE establishes an "MA PDU Session" with a CN (UPF) using a "3GPP access" wireless path via a RAN and a "non-3GPP access" wireless path via a wireless LAN (Local Area Network) such as Wi-Fi (registered trademark). "3GPP access" refers to an access network specified by 3GPP. "Non-3GPP access" refers to an access network other than "3GPP access." The UE uses the "MA PDU Session" to send and receive data between a DN (Data Network) such as the Internet outside the 5GC (CN of the 5G system). By using the "MA PDU Session", the UE can improve communication quality by expanding the communication bandwidth, reducing communication delays, and ensuring redundancy in the communication path.

[0004] Furthermore, Non-Patent Documents 1 and 2 specify a steering mode as a policy indicating how traffic related to a UE is transmitted when a "MA PDU Session" is established. The steering mode is notified from the CN to the UE when a "MA PDU Session" is established. The steering modes (1) to (5) specified in Non-Patent Documents 1 and 2 are shown below.

[0005] (1) "Active-Standby" In "Active-Standby," traffic is basically transmitted to the "Active" access network, and when the "Active" access network becomes unavailable, it switches to the "Standby" access network. After that, when the "Active" access network becomes available again, it switches back to the "Active" access network.

[0006] (2) "Smallest Delay" "Smallest Delay" transmits traffic to the access network with the smallest RTT (Round Trip Time). The UE and UPF can measure the RTT of "3GPP access" and "non-3GPP access". If one access network becomes unavailable, all traffic is transmitted through the other available access network. "Smallest Delay" is only applicable to "non-GBR SDF".

[0007] (3) "Load-Balancing" "Load-Balancing" is a mode used when distributing traffic across two sessions. Percentage information is set to indicate the percentage of transmission for each session. If one access network becomes unavailable, the other access network operates as if its percentage was set to 100%. "Load-Balancing" is only applicable to "non-GBR" traffic.

[0008] (4) "Priority-based" "Priority-based" is a mode used when distributing traffic between two sessions. All traffic is transmitted over the access network with the higher priority until the access network with the higher priority is determined to be "congested." In the event of congestion, traffic is also transmitted over the access network with the lower priority. The determination of congestion depends on the UE and the implementation of the UPF. If one access network becomes unavailable, all traffic is transmitted over the other access network. "Priority-based" is only applicable to "non-GBR" traffic.

[0009] (5) "Redundant" When both access networks are available, traffic is transmitted redundantly through both access networks. "Primary access" information may be provided to the UE and UPF by the "ATSSS rule" and "N4 rule." "Primary access" may be "3GPP access" or "non-3GPP access." When "Primary access" information is provided, the UE and UPF transmit all traffic through "Primary access" and transmit redundant traffic through other access networks. In redundancy, how much data the UE and UPF duplicate depends on the implementation. When "Primary Access" information is not provided, the UE and UPF always duplicate all data and transmit it through both access networks.

[0010] Furthermore, non-patent document 3 describes service requirements defined by 3GPP, including, for example, "DualSteer device," "Traffic steering," and "Traffic switching."

[0011] "DualSteer (DS)" refers to the function of a communication device to simultaneously connect to two "3gpp access" and perform "Traffic steering" or "Traffic switching." "DualSteer device" refers to a communication device equipped with DS.

[0012] "Traffic steering" refers to a communication device simultaneously connecting to two "3gpp accesses," selecting one "3gpp access" based on some criteria, and transmitting traffic through the selected "3gpp access."

[0013] "Traffic switching" refers to a communication device simultaneously connecting to two "3gpp access" networks and seamlessly transferring traffic from one "3gpp access" to the other.

[0014] There are two types of DS devices:

[0015] One type of DS device is a "DualSteer device with two separate UEs." A "DualSteer device with two separate UEs" is a DS device that logically has two UEs and is capable of simultaneous transmission using two "3gpp accesses."

[0016] Another type of DS device is a "DualSteer device with a single UE." A "DualSteer device with a single UE" is a DS device that logically has a single UE and can select either one of two simultaneously connected "3gpp access" for communication (non-simultaneous transmission).

[0017] As specified in "Traffic steering" and "Traffic switching," the unit of traffic transmission in DS is "application" or "service." Therefore, it is not possible to split or duplicate the traffic of one application and transmit or receive it simultaneously over two "3GPP access" services. The same applies to service traffic.

[0018] Also, the DS is terminated between the DS device and the UPF.

[0019] Regarding traffic transmission rules for a communication device simultaneously connecting to two "3GPP accesses," when a communication device simultaneously connects to multiple "3GPP accesses," the communication device and the UPF have policies that specify how traffic is distributed to each "3GPP access." The five steering modes mentioned above, "Active-Standby," "Smallest Delay," "Load-Balancing," "Priority-based," and "Redundant," are specified as traffic transmission policies when a communication device and a UPF simultaneously connect to two "3GPP accesses." The steering mode is one of the attributes in the "ATSSS rule" for the communication device and the "Multi-access rule (MAR)" for the UPF.

[0020] A communication device can have multiple "ATSSS rules." An "ATSSS rule" has priority information and a traffic descriptor (such as information in a 5-tuple). When transmitting traffic, the communication device checks the traffic descriptor in the order of priority indicated in the "ATSSS rule," decides to adopt the rule that matches all of the conditions included in the traffic descriptor, and transmits the traffic in the steering mode included in the decided rule.

[0021] The UPF has a rule called a "Packet detection rule (PDR)." When transmitting a packet, the UPF identifies the packet using the PDR and derives a MAR that matches the identified packet. The MAR contains steering mode information. The UPF transmits traffic in the steering mode indicated by the derived MAR.

[0022] 3GPP, TS 23.501, V18.2.0, 2023-063GPP, TS 23.502, V18.2.0, 2023-063GPP, TS 22.261, V19.6.0, 2024-03

[0023] The above-mentioned existing steering modes are defined on the premise that two "3GPP accesses" can be used simultaneously for one "application" or "service." For this reason, there exist modes such as "Load-Balancing" and "Priority-based" that cannot satisfy "DS-specific constraints (related to simultaneous transmission)." On the other hand, steering modes such as "Load-Balancing" and "Priority-based" are defined to achieve purposes such as preventing congestion and distributing the load for each "3GPP access." Therefore, it is preferable that these steering modes be applicable to DS devices.

[0024] Furthermore, even if the steering mode is usable directly for the DS (such as "Active-standby" or "Smallest-delay"), it is preferable to be able to issue appropriate rules according to the configuration of the DS device in order to maintain normal operation.

[0025] For example, when the DS device is a "DualSteer device with a single UE," there may be a case where the steering modes of the provided rules are inconsistent. As a specific example, suppose that the "DualSteer device with a single UE" DS device simultaneously connects to a first "3gpp access" and a second "3gpp access," and a first application on the DS device is associated with a first "ATSSS rule," and a second application is associated with a second "ATSSS rule." Furthermore, suppose that the steering mode of the first "ATSSS rule" is "active-standby," and the steering mode of the second "ATSSS rule" is "smallest-delay." In this case, when the network set as "Active" in the first "ATSSS rule" is the first "3gpp access" and the network determined to have smaller delay in the second "ATSSS rule" is the second "3gpp access," the DS device may decide to perform "simultaneous transmission" even though it does not have the "simultaneous transmission" function because it is a "DualSteer device with a single UE."

[0026] Another example is the use of "Priority-based." In "Priority-based," if congestion is detected on the "3GPP access" side set to "high-priority," traffic is divided and sent to the "3GPP access" side set to "low-priority." However, since DS prohibits dividing the traffic of a single "application" or "service," "Priority-based" cannot be applied as is.

[0027] Another example is the use of "Load-Balancing." "Load-Balancing" divides traffic into preset ratios and transmits it. However, DS prohibits dividing the traffic of a single "application" or "service," so "Load-Balancing" cannot be applied as is.

[0028] The present invention has been made in consideration of these circumstances, and its purpose is to provide an appropriate traffic transmission policy when connecting to two "3gpp access" simultaneously, depending on the configuration of the DS device.

[0029] One aspect of the present invention is a network apparatus provided in a core network in a mobile communication system having a core network connected to multiple radio access networks, wherein communication device configuration information is information indicating a first configuration in which a communication device can communicate using multiple radio access networks simultaneously, a second configuration in which a communication device can communicate using any one of the multiple radio access networks, or both the first and second configurations, and the network apparatus includes a policy information provider that provides policy information indicating how a target communication device selectively uses multiple radio access networks, and the policy information provider determines the policy information for the target communication device based on the communication device configuration information. Another aspect of the present invention is the above-mentioned network apparatus, wherein the policy information provider determines the policy information for the target communication device based on default values ​​of the communication device configuration information. Another aspect of the present invention is the above-mentioned network apparatus, wherein the policy information provider determines the policy information for the target communication device based on the communication device configuration information notified from the target communication device. In one aspect of the present invention, the core network includes a communication device configuration information storage unit that stores the communication device configuration information, and the policy information providing unit acquires the communication device configuration information from the communication device configuration information storage unit. In another aspect of the present invention, the communication device configuration information storage unit stores the communication device configuration information notified from the communication device. In another aspect of the present invention, the policy information providing unit determines the policy information for the target communication device based on previously provided policy information for the target communication device.In one aspect of the present invention, in the above-mentioned network apparatus, the core network includes a provided policy information storage unit that stores the policy information previously provided for each communication device, and the policy information providing unit acquires the policy information previously provided for the target communication device from the provided policy information storage unit. In another aspect of the present invention, the above-mentioned network apparatus includes a PCF (Policy Control Function), and information to be included in a policy request from an SMF (Session Management Function) to the PCF is extended. In another aspect of the present invention, in the above-mentioned network apparatus, the policy information may include a steering mode in which the communication device and a UPF (User Plane Function) monitor congestion states of two radio access networks to which the communication device is simultaneously connected, and, if one radio access network is determined to be congested, switch traffic from the radio access network determined to be congested to the other radio access network. One aspect of the present invention is a network device in which the policy information has a second rule identifier separate from its own first rule identifier, and may include a steering mode that selects a radio access network different from the radio access network selected by the rule specified by the second rule identifier, and transmits traffic via the selected radio access network.

[0030] One aspect of the present invention is a communication method executed by a network device provided in a core network in a mobile communication system having a core network connected to multiple radio access networks, wherein communication device configuration information is information indicating a first configuration in which the communication device can communicate using multiple radio access networks simultaneously, a second configuration in which the communication device can communicate using any one of the multiple radio access networks, or both the first configuration and the second configuration, and the communication method includes a policy information providing step of providing policy information indicating how a target communication device can use multiple radio access networks appropriately, and the policy information providing step determines the policy information for the target communication device based on the communication device configuration information.

[0031] One aspect of the present invention is a computer program to be executed by a computer of a network device provided in a core network in a mobile communication system having a core network connected to multiple radio access networks, wherein communication device configuration information is information indicating a first configuration in which the communication device can communicate using multiple radio access networks simultaneously, a second configuration in which the communication device can communicate using any one of the multiple radio access networks, or both the first configuration and the second configuration, and the computer is caused to execute a policy information providing step of providing policy information indicating how a target communication device should use multiple radio access networks, and the policy information providing step determines the policy information for the target communication device based on the communication device configuration information.

[0032] According to the present invention, it is possible to obtain an effect that a traffic transmission policy when simultaneously connecting to two "3gpp access" can be appropriately provided according to the configuration of the DS device.

[0033] It is a block diagram showing a schematic configuration example of a mobile communication system according to an embodiment. It is a sequence diagram showing an example of a policy information providing method according to an embodiment. It is a diagram showing a schematic architecture of a conventional 5G system.

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration example of a mobile communication system according to one embodiment. In FIG. 1, a communication device 10 is a DS device. The communication device 10 is connectable to RANs (radio access networks) 30 (30_1, 30_2) that are "3GPP access." The communication device 10 is connectable to two RANs 30_1, 30_2 simultaneously. Examples of the RAN 30 include a base station (4G base station) of a fourth-generation mobile communication system (4G system) and a base station (5G base station) of a 5G system. The RANs 30_1, 30_2 are connected to a CN (core network) 50 of the mobile communication system 1.

[0035] The CN 50 of the mobile communication system 1 includes a policy information providing unit 51, a communication device configuration information storage unit 52, and a provided policy information storage unit 53. The policy information providing unit 51, the communication device configuration information storage unit 52, and the provided policy information storage unit 53 are provided in an apparatus (network apparatus) included in the CN 50. The policy information providing unit 51, the communication device configuration information storage unit 52, and the provided policy information storage unit 53 may be provided in one network apparatus included in the CN 50, or may be provided in a distributed manner in multiple network apparatuses included in the CN 50.

[0036] The communication device configuration information in this embodiment is information indicating a first configuration ("DualSteer device with two separate UEs") in which the communication device 10 (DS device) can perform communication using multiple RANs 30 simultaneously (simultaneous transmission), a second configuration ("DualSteer device with a single UE") in which the communication device 10 (DS device) can perform communication using any one of multiple RANs 30 (non-simultaneous transmission), or both the first configuration and the second configuration.

[0037] The policy information providing unit 51 provides policy information indicating how the target communication device 10 should use the plurality of RANs 30. The policy information indicates how traffic should be distributed to each RAN 30 when the communication device 10 is connected to the plurality of RANs 30 simultaneously.

[0038] The policy information providing unit 51 determines policy information for the target communication device 10 based on the communication device configuration information. The policy information providing unit 51 may determine policy information for the target communication device 10 based on default values ​​of the communication device configuration information. The policy information providing unit 51 may determine policy information for the target communication device 10 based on communication device configuration information notified from the target communication device 10. The policy information providing unit 51 may acquire communication device configuration information from an NF (communication device configuration information storage unit) that stores communication device configuration information.

[0039] The policy information providing unit 51 may further determine the policy information regarding the target communication device 10 based on policy information regarding the target communication device 10 that has been provided in the past.

[0040] The communication device configuration information storage unit 52 stores the communication device configuration information. The policy information providing unit 51 may acquire the communication device configuration information from the communication device configuration information storage unit 52.

[0041] The communication device configuration information storage unit 52 may store the communication device configuration information notified from the communication device 10 for each communication device 10. The policy information providing unit 51 may acquire the communication device configuration information notified from the target communication device 10 from the communication device configuration information storage unit 52.

[0042] The provided policy information storage unit 53 stores policy information that has been provided in the past for each communication device. The policy information providing unit 51 may obtain policy information that has been provided in the past regarding the target communication device 10 from the provided policy information storage unit 53.

[0043] [Regarding Communication Device Configuration Information] The communication device configuration information will be described in detail below. An example of a communication device configuration information acquisition method in which the NF (network function) of the CN 50 acquires the communication device configuration information will be shown below.

[0044] (Example 1 of communication device configuration information acquisition method) In the "Registration" procedure of the communication device 10, the communication device configuration information is included in a message transmitted from the communication device 10 to the CN 50. The NF acquires the communication device configuration information from the message.

[0045] (Example 2 of communication device configuration information acquisition method) In the "PDU (Packet Data Unit) Session" establishment procedure, communication device configuration information is included in a message transmitted from the communication device 10 to the CN 50. The NF acquires the communication device configuration information from the message.

[0046] (Example 3 of Communication Device Configuration Information Acquisition Method) As one piece of information at the time of the user's contract, communication device configuration information of the communication device 10 linked to the user is stored in advance in the UDM or UDR.

[0047] (Example 4 of Communication Device Configuration Information Acquisition Method) The communication device 10 notifies the CN 50 of the communication device configuration information at any timing in response to a user operation of a setting application or the like.

[0048] Note that the communications device 10 includes "DualSteer instruction information (information indicating the use of DualSteer)" as information different from the communications device configuration information in the "Registration" and "PDU Session establishment" request messages. Alternatively, the presence or absence of communications device configuration information in the "Registration" and "PDU Session establishment" request messages may also serve as an indication of the presence or absence of DualSteer instruction information. In this case, the presence of communications device configuration information means the presence of DualSteer instruction information, and the absence of communications device configuration information means the absence of DualSteer instruction information.

[0049] The communication device configuration information may include, for example, the following two values: Communication device configuration information = [single UE, two separate UEs] The communication device configuration information may include either "single UE" or "two separate UEs", or may include both "single UE" and "two separate UEs". "Single UE" indicates that the communication device 10 can operate as a "DualSteer device with a single UE". "Two separate UEs" indicates that the communication device 10 can operate as a "DualSteer device with two separate UEs". If the communication device configuration information includes both "single UE" and "two separate UEs", it indicates that the communication device 10 can operate as either a "DualSteer device with a single UE" or a "DualSteer device with two separate UEs".

[0050] The communication device configuration information is not limited to the above format.

[0051] For example, the communication device configuration information may have a value of "single UE indication." In this case, the communication device 10 can only operate as a "DualSteer device with a single UE."

[0052] For example, the communication device configuration information may have a value of "two separate UEs." In this case, the communication device 10 can only operate as a "DualSteer device with two separate UEs."

[0053] For example, the communication device configuration information may be a "simultaneous transmission indication," which indicates that the communication device 10 is capable of simultaneous transmission, i.e., that the communication device 10 is capable of operating as a "DualSteer device with two separate UEs."

[0054] In addition, if the "DualSteer instruction information (information indicating the use of DualSteer)" and the communication device configuration information are separated, when the communication device configuration information is not included, it may be determined that the communication device 10 is either a "DualSteer device with a single UE" or a "DualSteer device with two separate UEs." In this case, either a "DualSteer device with a single UE" or a "DualSteer device with two separate UEs" may be set in the CN 50 as the default value of the communication device configuration information.

[0055] The CN 50 may include an NF (communication device configuration information storage unit) that manages communication device configuration information. The NF that manages the communication device configuration information may be any existing NF (e.g., AMF, SMF, UDM, UDR, PCF, etc.). Alternatively, a new NF that stores communication device configuration information (e.g., an NF named "DCIMF: Device Configuration Information Management Function") may be provided.

[0056] Communication device configuration information may be transmitted between NFs using existing NF services (e.g., Namf_xxx, Nsmf_xxx, Nudm, etc.) In this case, the existing NF services are extended to include communication device configuration information.

[0057] [Policy Information] Policy information will be described in detail. The policy information according to this embodiment indicates a policy for DS (DualSteer). The policy for DS held by the communication device 10 and the UPF is called a "DS rule." The DS rule associated with the traffic of the communication device 10 may be different between the communication device 10 and the UPF. The DS rule has at least the following information (1-1), (1-2), and (1-3). However, the information held by the DS rule is not limited to this.

[0058] (1-1) Rule identifier. The rule identifier may be a global identifier or a local identifier. (1-2) Traffic identification information. The traffic identification information is included only in the DS rule of the communication device 10. (1-3) DS steering mode.

[0059] The DS steering mode takes one of the following values ​​(2-1) to (2-4): (2-1) "Active-standby". "Active-standby" is the same as the existing steering mode "Active-Standby". (2-2) "Smallest-delay". "Smallest-delay" is the same as the existing steering mode "Smallest Delay".

[0060] (2-3) "Congestion-based". "Congestion-based" is a new steering mode. In "Congestion-based", the communication device 10 and the UPF monitor the congestion states of two RANs 30_1 and 30_2 to which the communication device 10 is simultaneously connected, and when one of the RANs 30 is determined to be in a congested state, the UPF switches traffic from the RAN 30 determined to be in a congested state to the other RAN 30 ("Traffic switching").

[0061] In the existing 3GPP specifications, the communication device 10 and the UPF have a function of measuring the round trip time (RTT) between the communication device 10 and the UPF, and the packet loss rate (PLR) between the communication device 10 and the UPF. For example, the communication device 10 and the UPF may calculate a congestion evaluation value by multiplying the RTT and the PLR, and may determine that a congestion state exists when the calculated congestion evaluation value exceeds a predetermined threshold. The method of determining the congestion state is not limited to this.

[0062] (2-4) "SDF-level Load-balancing". "SDF-level Load-balancing" is a new steering mode. In "SDF-level Load-balancing", a DS rule has a rule identifier (second rule identifier) ​​of another DS rule separate from its own rule identifier (first rule identifier), and selects a RAN 30 different from the RAN 30 selected by the DS rule specified by the second rule identifier, and transmits traffic through the selected RAN 30 ("Traffic steering").

[0063] [Policy Information Management Method] A method for managing policy information will be described in detail. In order to provide appropriate policy information, the CN 50 may include an NF (provided policy information storage unit) that manages policy information (provided policy information) that has been previously provided to the communication device 10 and the UPF.

[0064] The NF that manages the provided policy information may be any existing NF (e.g., PCF, UDM, UDR, etc.), or a new NF that manages the provided policy information (e.g., an NF named "DPMF: Distributed Policy Management Function") may be provided.

[0065] The provided policy information is uniquely identified within the CN 50. For example, a global identifier may be provided for the provided policy information. Alternatively, the device identifier of the communication device 10 (for example, a Permanent Equipment Identifier (PEI) in a 5G system) may be used as the identifier of the provided policy information.

[0066] The provided policy information has the following information (3-1) and (3-2): (3-1) Provided policy information identifier. (3-2) Communication device identifier. The communication device identifier may be in the format of {UE identifier list {DS rule list}}, for example.

[0067] The DPMF may manage both the provided policy information and the communication device configuration information, or the DCIMF may manage both the communication device configuration information and the provided policy information.

[0068] [Policy Information Providing Method] A method for providing policy information will be described in detail with reference to Fig. 2. Fig. 2 is a sequence diagram showing an example of a policy information providing method according to this embodiment. The policy information providing method of Fig. 2 is an example according to this embodiment, in which policy information is provided when a PDU session for DS is established.

[0069] The policy information providing method of Fig. 2 may be implemented in an "SM Policy Association" or may be included at any location in an existing "PDU Session" establishment procedure. Also, the policy information providing method of Fig. 2 may be implemented at any timing in any procedure such as a "Service Request" or a "PDU Session modification."

[0070] 2, the PCF 120 includes a policy information providing unit 51. Also provided is a NF 130 including a communication device configuration information storage unit 52 and a provided policy information storage unit 53. The NF 130 may be any existing NF, or may be a new NF (DCIMF, DPMF).

[0071] (Step S1) The communication device 10 notifies the NF 130 of the communication device configuration information at the timing of "Registration" or establishment of a "PDU Session." Note that the communication device configuration information may be statically managed by the NF 130 (e.g., UDM or UDR), and the operator of the mobile communication system 1 may update the communication device configuration information of the NF 130 when a user signs a contract.

[0072] (Step S2) The SMF 110 sends a policy request related to the target communication device 10 (hereinafter referred to as the target device 10) to the PCF 120. When making this policy request, the SMF 110 notifies the PCF 120 of "DualSteer instruction information" in addition to any information. Furthermore, when the PCF 120 does not recognize the UE identifier or device identifier of the target device 10, the SMF 110 notifies the PCF 120 of the UE identifier or device identifier of the target device 10.

[0073] In addition, if the SMF 110 is an NF 130 that manages communication device configuration information and provided policy information, the SMF 110 may notify the PCF 120 of the communication device configuration information and provided policy information of the target device 10 when a policy is requested.

[0074] (Step S3) The PCF 120 recognizes from the "DualSteer instruction information" notified in the policy request for the target device 10 from the SMF 110 that the policy request is a request for a policy for DS.

[0075] If the PCF 120 is notified of the communication device configuration information and provided policy information of the target device 10 in response to the policy request from the SMF 110 regarding the target device 10, the process proceeds to step S5.

[0076] If the PCF 120 is the NF 130 that manages the communication device configuration information and the provided policy information, the process proceeds to step S5.

[0077] If the communication device configuration information of the target device 10 is not notified in the policy request for the target device 10 from the SMF 110, the PCF 120 notifies the NF 130 of the UE identifier or device identifier of the target device 10 and requests the communication device configuration information of the target device 10.

[0078] If the PCF 120 is not notified of the policy information already provided for the target device 10 in a policy request for the target device 10 from the SMF 110, the PCF 120 notifies the NF 130 of the UE identifier or device identifier of the target device 10 and requests the policy information already provided for the target device 10.

[0079] (Step S4) The PCF 120 receives a response to the request of step S3 from the NF 130. If the NF 130 responds with the information requested from the NF 130 in step S3, the process proceeds to step S5. On the other hand, if the NF 130 does not respond with the communication device configuration information of the target device 10 requested from the NF 130 in step S3, the PCF 120 uses a default value of the communication device configuration information for the communication device configuration information of the target device 10. The default value of the communication device configuration information is either "DualSteer device with a single UE" or "DualSteer device with two separate UEs", which is set in advance in the PCF 120. The default value of the communication device configuration information may be, for example, "DualSteer device with a single UE".

[0080] If the NF 130 does not return the provided policy information of the target device 10 requested in step S3, the PCF 120 recognizes that the provided policy information of the target device 10 does not exist.

[0081] (Step S5) The PCF 120 determines policy information related to the target device 10. The policy information is information indicating a DS rule. The DS rule includes a rule identifier and a DS steering mode. The DS rule of the target device 10 further includes traffic identification information.

[0082] The PCF 120 determines a DS rule for the target device 10 based on the communication device configuration information of the target device 10. If there is provided policy information for the target device 10, the PCF 120 determines a DS rule for the target device 10 based on the communication device configuration information of the target device 10 and the provided policy information.

[0083] For example, if the communication device configuration information of the target device 10 is "DualSteer device with a single UE," PCF 120 excludes "SDF-level Load-balancing" from the DS steering mode candidates for the target device 10, and determines the DS steering mode for the target device 10 from the remaining DS steering mode candidates according to a specified DS rule determination method.

[0084] In addition, if the communication device configuration information of the target device 10 is "DualSteer device with a single UE," the PCF 120 uses the provided policy information regarding the target device 10 to determine the DS rule so that the RAN 30 selected by the DS steering mode is always one of the RANs 30_1 and 30_2 to which the target device 10 is simultaneously connected.

[0085] In addition, if the CN 50 does not have a provided policy information storage unit 53 that manages provided policy information, and the communication device configuration information of the target device 10 is "DualSteer device with a single UE," the PCF 120 determines the DS steering mode for the target device 10 to be "Active-standby."

[0086] (Step S6) The PCF 120 responds to the SMF 110 with policy information indicating the DS rule for the determined target device 10. The SMF 110 sets the DS rule for each of the target device 10 and the UPF based on the DS rule indicated in the policy information received from the PCF 120.

[0087] According to this embodiment, the effect is achieved that DS rules (traffic transmission policies) when simultaneously connecting to two RANs 30 (3GPP access) can be appropriately provided according to the configuration of the communication device 10 (DS device).

[0088] In the above-described embodiment (Figure 1), an example was given of a case where the communication device 10 is connected to two RANs 30 simultaneously, but the present invention may also be applied to a case where the communication device 10 is connected to three or more RANs 30 simultaneously.

[0089] Furthermore, the above-described embodiments are applicable to mobile communication systems such as 5G systems, B5G systems, and 6G systems.

[0090] This will enable, for example, improvements to the overall service quality of mobile communication systems, thereby contributing to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0091] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present invention.

[0092] Furthermore, a computer program for implementing the functions of each of the above-described devices may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read and executed by a computer system. Note that the term "computer system" may also include hardware such as an OS and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a DVD (Digital Versatile Disc), or a storage device such as a hard disk built into a computer system.

[0093] Furthermore, the term "computer-readable recording medium" also includes a storage medium that stores a program for a certain period of time, such as a volatile memory (e.g., a dynamic random access memory (DRAM)) within a computer system that serves as a server or client when the program is transmitted via a network such as the Internet or a communication line such as a telephone line. The program may also be transmitted from a computer system that stores the program in a storage device or the like to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may also be a program that realizes part of the aforementioned functions. Furthermore, the program may be a so-called differential file (differential program) that can realize the aforementioned functions in combination with a program already stored in the computer system.

[0094] According to the present invention, a traffic transmission policy when simultaneously connecting to two "3gpp access" can be appropriately provided according to the configuration of the DS device.

[0095] REFERENCE SIGNS LIST 1... mobile communication system, 10... communication device, 30... RAN, 50... core network, 51... policy information providing unit, 52... communication device configuration information storage unit, 53... provided policy information storage unit

Claims

1. A network apparatus provided in a core network in a mobile communication system having a core network connected to multiple radio access networks, wherein communication device configuration information is information indicating a first configuration in which the communication device can communicate using multiple radio access networks simultaneously, a second configuration in which the communication device can communicate using any one of the multiple radio access networks, or both the first configuration and the second configuration, and the network apparatus has a policy information providing unit that provides policy information indicating how a target communication device can selectively use multiple radio access networks, and the policy information providing unit determines the policy information for the target communication device based on the communication device configuration information.

2. The network device according to claim 1, wherein the policy information providing unit determines the policy information for the target communication device based on default values ​​of the communication device configuration information.

3. The network device according to claim 1, wherein the policy information providing unit determines the policy information related to the target communication device based on the communication device configuration information notified from the target communication device.

4. The network device according to claim 1, wherein the core network comprises a communication device configuration information storage unit that stores the communication device configuration information, and the policy information providing unit acquires the communication device configuration information from the communication device configuration information storage unit.

5. The network device according to claim 4, wherein the communication device configuration information storage unit stores the communication device configuration information notified from the communication device.

6. The network device according to claim 1, wherein the policy information providing unit further determines the policy information related to the target communication device based on the policy information related to the target communication device that has been provided in the past.

7. The network device according to claim 6, wherein the core network comprises a provided policy information storage unit that stores the policy information that has been provided in the past for each communication device, and the policy information providing unit acquires the policy information that has been provided in the past regarding the target communication device from the provided policy information storage unit.

8. The network device according to claim 1, wherein the network device has a PCF (Policy Control Function), and information included in a policy request from an SMF (Session Management Function) to the PCF is extended.

9. The network device according to claim 1, wherein the policy information may include a steering mode in which the communication device and a UPF (User Plane Function) monitor congestion states of two radio access networks to which the communication device is simultaneously connected, and, if one radio access network is determined to be in a congested state, switches traffic from the radio access network determined to be in a congested state to the other radio access network.

10. The network device according to claim 1, wherein the policy information may include a steering mode that has a second rule identifier separate from its own first rule identifier, selects a radio access network different from the radio access network selected by the rule specified by the second rule identifier, and transmits traffic through the selected radio access network.

11. A communication method executed by a network device in a core network in a mobile communication system having a core network connected to multiple radio access networks, wherein communication device configuration information is information indicating a first configuration in which the communication device can communicate using multiple radio access networks simultaneously, a second configuration in which the communication device can communicate using any one of the multiple radio access networks, or both the first configuration and the second configuration, and the method includes a policy information providing step of providing policy information indicating how a target communication device can selectively use multiple radio access networks, and the policy information providing step determines the policy information related to the target communication device based on the communication device configuration information.

12. A computer program to be executed by a computer of a network device provided in a core network in a mobile communication system having a core network connected to multiple radio access networks, wherein communication device configuration information is information indicating a first configuration in which the communication device can communicate using multiple radio access networks simultaneously, a second configuration in which the communication device can communicate using any one of the multiple radio access networks, or both the first configuration and the second configuration, and the computer is caused to execute a policy information providing step of providing policy information indicating how a target communication device can selectively use multiple radio access networks, and the policy information providing step determines the policy information for the target communication device based on the communication device configuration information.

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