Network node and base station

Abstract

This network node performs session management and comprises: a reception unit that receives, from a network node that performs access and mobility management, a message requesting establishment of a protocol data unit (PDU) session, said message including an identifier of a backhaul line in a backhaul system; a control unit that determines whether the backhaul line needs to be used; and a transmission unit that transmits, to a network node that performs policy control, a policy determination request message including the identifier and information requesting securement of communication resources necessary in the backhaul system.

Description

Network Node and Base Station , ,

[0004] ,

[0006] ,

[0005] ,

[0001] The present invention relates to a network node, a radio access network, and a communication method in a communication system.

[0002] The 5G communication system (5GS) provides advanced QoS (Quality of Service) management compared to 4G LTE, enabling low-latency and highly reliable communication. To achieve this, it is necessary to ensure sufficient bandwidth for the N3 interface that connects the base station (e.g., HgNB or MWAB-gNB) to the core network. In the 4G system, a method for securing communication resources through cooperation with the fixed access network has been specified, but in the 5G system, the specifications for securing communication resources in the N3 interface have not been established. Also, when Home UPF is selected, securing communication resources in the fixed access network becomes unnecessary, but there is no dynamic resource management method considering such conditions.

[0003] 3GPP TS23.501 V19.2.1 (2025-01)

[0004] However, due to insufficient bandwidth of the N3 interface, there is a risk that the QoS intended by 5GS cannot be achieved. This can be particularly significant in communication when connecting a Home gNB within a home using a fixed access network to the N3 interface, or in communication when connecting a MWAB gNB (Multi-Access Wireless Access Base Station gNB) using a BH 5GS to the N3 interface.

[0005] Furthermore, in the 5G system, there are no specifications for requesting the securing of communication resources in the fixed access network or BH 5GS, and resource management is insufficient. Also, no management method considering the condition of not requiring resource securing when Home UPF is selected has been established. Therefore, an efficient resource securing mechanism through cooperation with the fixed access network or BH 5GS is required.

[0006] The network node in this embodiment includes a receiving unit that receives a message requesting the establishment of a PDU (Protocol Data Unit) session, which includes an identifier for a backhaul line in the backhaul system, from a network node that performs session management and access and mobility management; a control unit that determines whether it is necessary to use the backhaul line; and a transmitting unit that sends a policy decision request message to a network node that performs policy control, which includes the identifier and information requesting that the necessary communication resources be secured in the backhaul system.

[0007] According to this embodiment, communication resources between the base station (e.g., HgNB or MWAB gNB) and the core network can be secured efficiently and appropriately.

[0008] This is a diagram illustrating an example of a communication system. This is a sequence diagram showing an example of the IPsec Tunneling establishment procedure in this embodiment. This is a sequence diagram showing an example of the PDU session establishment procedure (when DNN=local access) in this embodiment. This is a sequence diagram showing an example of the PDU session establishment procedure (when DNN=local access) in this embodiment. This is a sequence diagram showing an example of the PDU session establishment procedure (when DNN=Internet) in this embodiment. This is a sequence diagram showing an example of the PDU session establishment procedure (when DNN=Internet) in this embodiment. This is a sequence diagram showing an example of the PDU session establishment procedure (when DNN=Internet) in this embodiment. This is a diagram showing an example of the PDU session establishment procedure (when DNN=Internet) in this embodiment. This is a diagram showing an example of the functional configuration of a base station and network node in this embodiment. This is a diagram showing an example of the functional configuration of a terminal in this embodiment. This is a diagram showing an example of the hardware configuration of a base station, terminal and network node in this embodiment. This is a diagram showing an example of the vehicle configuration in this embodiment.

[0009] This embodiment will be described below with reference to the drawings. Note that the embodiments described below are examples, and the embodiments to which the present invention applies are not limited to those described below.

[0010] In the operation of the communication system of this embodiment, existing technologies will be used as appropriate. Existing technologies include, for example, existing communication methods based on the 3GPP standard, such as NR (New Radio) (5G) / 5GC (5G Core network). However, existing technologies are not limited to NR / 5GC, but also include LTE, LTE-Advanced and NR (5G) and later methods, or wireless LAN (Local Area Network).

[0011] In this embodiment, "configuring" wireless parameters means either pre-configuring predetermined values, or configuring wireless parameters notified by a network node or UE.

[0012] Figure 1 is a diagram illustrating an example of a communication system. As shown in Figure 1, the communication system consists of a UE and multiple network nodes. Hereafter, one network node will be assumed to correspond to each function, however, one network node may implement multiple functions, or multiple network nodes may implement one function. Furthermore, the "connection" described below may be a logical connection or a physical connection.

[0013] The RAN (Radio Access Network) is a network node with radio access functionality, which may include a base station 10, and is connected to the UE, AMF (Access and Mobility Management Function), and UPF (User plane function). The AMF is a network node that has functions such as terminating the RAN interface, terminating the NAS (Non-Access Stratum), registration management, connection management, reachability management, and terminal mobility management. The UPF is a network node that interconnects with the DN (Data Network) and has functions related to processing user plane data, such as PDU (Protocol Data Unit) session points to the outside, packet routing and forwarding, and user plane QoS (Quality of Service) handling. The UPF and DN constitute a network slice. In the wireless communication network of this embodiment, multiple network slices are constructed.

[0014] AMF is connected to UE, RAN, SMF (Session Management function), NSSF (Network Slice Selection Function), NEF (Network Exposure Function), NRF (Network Repository Function), UDM (Unified Data Management), AUSF (Authentication Server Function), PCF (Policy Control Function), and AF (Application Function). AMF, SMF, NSSF, NEF, NRF, UDM, AUSF, PCF, and AF are network nodes that are interconnected via interfaces based on their respective services: Namf, Nsmf, Nnssf, Nnef, Nnrf, Nudm, Nausf, Npcf, and Naf.

[0015] SMF is a network node with functions such as session management, IP (Internet Protocol) address allocation and management for UEs, DHCP (Dynamic Host Configuration Protocol) functionality, ARP (Address Resolution Protocol) proxy, and roaming functionality. NEF is a network node with the function of notifying other NFs (Network Functions) of capabilities and events. NSSF is a network node with functions such as selecting the network slice to which the UE connects, determining the allowed NSSAI (Network Slice Selection Assistance Information), determining the NSSAI to be configured, and determining the AMF set to which the UE connects. PCF is a network node with the function of controlling network policies. AF is a network node with the function of controlling application servers. NRF is a network node with the function of discovering NF instances that provide services. UDM is a network node that manages subscriber data and authentication data. UDM is connected to UDR (User Data Repository) which holds this data.

[0016] Recent 5G communication systems (5GS) offer more advanced QoS management compared to conventional 4G LTE, achieving low latency and high reliability. However, in 5G network design, if the bandwidth of the N3 interface supporting communication between base stations (e.g., HgNB and MWAB-gNB) and the core network is not sufficiently secured, the intended QoS may not be achieved.

[0017] In 4G systems, coordination with a fixed access network is specified to secure communication resources between the HeNB (Home eNodeB) and the core network. On the other hand, in 5G systems, coordination with a fixed access network is not specified for securing communication resources for the N3 interface between the HgNB and the core network. Furthermore, coordination with BH 5GS is not specified for securing communication resources for the N3 interface between the MWAB gNB and the core network.

[0018] Furthermore, in 5G, a Home UPF (User Plane Function) that is placed adjacent to the HgNB is being considered. If a Home UPF is selected, it will not be necessary to secure communication resources for the fixed access network. However, this case has not yet been specifically considered or specified. Under these circumstances, there is a risk that efficient communication resource management will not be achieved while maintaining QoS.

[0019] This embodiment provides a method for efficiently securing communication resources at the N3 interface between a base station (HgNB or MWAB-gNB) and the core network, thereby achieving the QoS intended by 5GS. Furthermore, this embodiment provides a mechanism for dynamically managing communication resources in cooperation with a fixed access network and BH 5GS. The HgNB may also be referred to as a femtobase station.

[0020] First, the operation overview of this embodiment will be described. The base station (HgNB 10 or MWAB gNB 10B) transmits an Uplink NAS Transport during the PDU session establishment procedure. The base station includes an identifier (BH circuit identifier) ​​in the Uplink NAS Transport to identify the BH circuit that the base station uses for the N3 interface. Based on this identifier, the BH system (i.e., a fixed access network or BH 5GS) can identify the BH circuit that the base station uses for the N3 interface. This BH circuit identifier may be, for example, an IP address locally assigned by the LAN in the case of a fixed access network, or the PDU session ID of the BH PDU session in the case of a BH 5GS.

[0021] Next, AMF 30A sends the BH line identifier to SMF 30B. SMF 30B sends a message to PCF 30D containing the BH line identifier and information requesting cooperation with the BH system. PCF 30D sends a message to the BH system's policy control function requesting sufficient communication resources for data transfer on N3, including the BH line identifier. If the base station is HgNB 10, SMF 30B does not need to send the BH line identifier and information requesting cooperation with the BH system to PCF 30D when UE 20 is accessing HgNB 10 but selects Home UPF.

[0022] The operation of this embodiment will be described in detail below.

[0023] (Example 1) In Example 1 of this embodiment, the procedure for establishing a PDU session when the base station is HgNB 10 will be explained using Figures 2, 3A-3B, and 4A-4C.

[0024] The communication system in Example 1 includes UE 20, HgNB 10, Home UPF 11, RG 40A, BNG 40B, SeGW 40C, BPCF 40D, HgNB GW 50, AMF 30A, SMF 30B, UPF 30C, and PCF 30D. HgNB 10 and Home UPF 11 are included in the Femto Box. RG 40A, BNG 40B, SeGW 40C, and BPCF 40D are included in Fixed Broadband Access.

[0025] Figure 2 is a sequence diagram showing an example of the procedure for establishing IPsec Tunneling in Example 1.

[0026] As shown in Figure 2, in step S101, IPsec Tunneling is established between HgNB 10 and SeGW 40C. IPsec Tunneling is used to ensure the integrity, confidentiality, and retransmission prevention of data transmitted by HgNB 10. The IKE (Internet Key Exchange) protocol is used between HgNB 10 and SeGW 40C when establishing IPsec Tunneling, and authentication and cryptographic key exchange are performed between the two parties. Using the IPsec Tunneling established in step S101, steps S201 in Figure 3A and step S301 in Figure 5A are executed.

[0027] Furthermore, IPsec Tunneling plays a role in ensuring the security of traffic and control signals provided by HgNB 10, including data communication through the N2 and N3 interfaces. The application of IPsec Tunneling is necessary to enhance the security of communications across trust boundaries. SeGW 40C is responsible for ensuring a secure communication path while relaying traffic between the core network and HgNB 10.

[0028] (Example 1-1) Example 1-1 describes the PDU session establishment procedure in the case of DNN=local access in a configuration where the base station is HgNB 10, using Figures 3A-3B. Figure 3A-3B shows a series of steps.

[0029] The DNN (Data Network Name) is an identifier that identifies the data network to which the UE 20 connects, and is an example of an identifier for the connected network.

[0030] In step S201 of Figure 3A, UE 20 sends ULInformationTransfer(dedicatedNAS-Message(UL NAS transport(Payload container type(N1 SM information), Payload container(PDU Session Establishment request), DNN=local access))) to HgNB 10.

[0031] In step S202, HgNB 10 sends an Uplink NAS Transport (NAS-PDU (UL NAS transport (Payload container type (N1 SM information), Payload container (PDU Session Establishment request), DNN=local access, ULI, Tunnel Information for BBF))) to HgNB GW 50. The Tunnel Information for BBF (Broadband Forum) included in the Uplink NAS Transport is an example of an identifier that identifies the backhaul circuit within the backhaul system.

[0032] In step S203, HgNB GW 50 sends Uplink NAS Transport(NAS-PDU(UL NAS transport(Payload container type(N1 SM information), Payload container(PDU Session Establishment request), DNN=local access, ULI, Tunnel Information for BBF))) to AMF 30A.

[0033] In step S204, AMF 30A sends Nsmf_PDUSession_CreateSMContext request(SmContextCreateData(dnn=local access, n1SmMsg(PDU session establishment request), ueLocation, Tunnel Information for BBF)) to SMF 30B.

[0034] In step S205 of Figure 3B, the SMF 30B recognizes the following:

[0035] 1) The UE is hosted by an HgNB (recognized based on the gNB ID and local information included in ueLocation) 2) A Home UPF exists adjacent to the HgNB, and the Home UPF supports a DNN for local access (recognized by referring to local information or NRF) 3) DNN = local access is requested In step S206, SMF 30B determines the following:

[0036] 1) Select Home UPF 2) Do not request PCF to reserve BH resources In step S207, SMF 30B sends Npcf_SMPolicyControl_Create request to PCF 30D.

[0037] In step S208, PCF 30D sends the Npcf_SMPolicyControl_Create response to SMF 30B.

[0038] (Example 1-2) Example 1-2 describes the PDU session establishment procedure when the base station is HgNB 10 and DNN=Internet, using Figures 4A-4C. Figures 4A and 4B and Figures 4A and 4C represent a series of steps, respectively.

[0039] In step S301 of Figure 4A, UE 20 sends ULInformationTransfer(dedicatedNAS-Message(UL NAS transport(Payload container type(N1 SM information), Payload container(PDU Session Establishment request), DNN=Internet))) to HgNB 10.

[0040] In step S302, HgNB 10 sends Uplink NAS Transport(NAS-PDU(UL NAS transport(Payload container type(N1 SM information), Payload container(PDU Session Establishment request), DNN=Internet, ULI, Tunnel Information for BBF))) to HgNB GW 50.

[0041] In step S303, HgNB GW 50 sends Uplink NAS Transport(NAS-PDU(UL NAS transport(Payload container type(N1 SM information), Payload container(PDU Session Establishment request), DNN=Internet, ULI, Tunnel Information for BBF))) to AMF 30A.

[0042] In step S304, AMF 30A sends Nsmf_PDUSession_CreateSMContext request(SmContextCreateData(dnn=Internet, n1SmMsg(PDU session establishment request), ueLocation, Tunnel Information for BBF)) to SMF 30B.

[0043] In step S305 of FIG. 4B, SMF 30B recognizes the following.

[0044] 1) That the UE is served by the HgNB (recognized based on the gNB ID and local information included in ueLocation); 2) That a Home UPF co-located with the HgNB exists and that the Home UPF supports the DNN for local access (recognized by referring to local information or the NRF); and 3) That DNN = Internet is requested. In step S306, based on the recognition in S305, SMF 30B determines the following.

[0045] 1) Select a central UPF; 2) Request the PCF to secure BH resources. In step S307, SMF 30B sends Npcf_SMPolicyControl_Create request (SmPolicyContextData(backhaulResourceRequest(Tunnel Information for BBF))) to PCF 30D. Npcf_SMPolicyControl_Create request is an example of a policy decision request message. Npcf_SMPolicyControl_Create request includes information (e.g., backhaulResourceRequest) requesting to secure the communication resources necessary in the backhaul system and an identifier of the backhaul line (e.g., Tunnel Information for BBF).

[0046] In step S308, PCF 30D sends (BBF spec) Policy Authorization request (Tunnel Information for BBF) to BPCF 40D.

[0047] In step S309, BPCF 40D sends (BBF spec) Policy Authorization response to PCF 30D. [[ID=[]] [[ID=[]]

[0048] In step S310, the PCF 30D sends Npcf_SMPolicyControl_Create response (SmPolicyDecision(backhaulResourceRequestResult=success)) to the SMF 30B. The Npcf_SMPolicyControl_Create response is an example of a response message that includes information indicating the success or failure of securing communication resources (e.g., backhaulResourceRequestResult=success).

[0049] As another example of Embodiment 1-1, after step S304 in FIG. 4A, step S305A in FIG. 4C is executed.

[0050] In step S305A of FIG. 4C, the SMF 30B recognizes the following.

[0051] 1) That the UE is accommodated by the HgNB (recognized based on the gNB ID and local information included in ueLocation) 2) That there is a Home UPF co-located with the HgNB and that the Home UPF supports the DNN for the Internet (recognized by referring to local information or the NRF) 3) That DNN=Internet is requested. In step S306A, based on the recognition in S305A, the SMF 30B determines the following.

[0052] 1) Select a Home UPF 2) Do not request the PCF to secure BH resources. In step S307A, the SMF 30B sends a Npcf_SMPolicyControl_Create request to the PCF 30D.

[0053] In step S308A, the PCF 30D sends a Npcf_SMPolicyControl_Create response to the SMF 30B.

[0054] (Embodiment 2) In Embodiment 2 of this embodiment, using FIG. 5, the PDU session establishment procedure in the case of DNN=Internet in the configuration where the base station is the MWAB-gNB 10B will be described.

[0055] The communication system in Example 2 includes UE 20, MWAB-gNB 10, MWAB-UE 20A, BH NG-RAN 60A, BH 5GC 60B (including AMF, SMF, UPF, etc.), BH 5GC PCF 60C, AMF 30A, SMF 30B, and PCF 30D. MWAB-gNB 10 and MWAB-UE 20A are included in MWAB. MWAB-UE 20A, BH NG-RAN 60A, BH 5GC 60B, and BH 5GC PCF 60C are included in BH 5GS.

[0056] In step S401 of Figure 5, UE 20 sends ULInformationTransfer(dedicatedNAS-Message(UL NAS transport(Payload container type(N1 SM information), Payload container(PDU Session Establishment request), DNN=Internet))) to MWAB-gNB 10B.

[0057] In step S402, HgNB 10 sends Uplink NAS Transport(NAS-PDU(UL NAS transport(Payload container type(N1 SM information), Payload container(PDU Session Establishment request), DNN=Internet, ULI, BH PDU session ID (or MWAB-UE IP address)))) to AMF 30A. The BH PDU session ID (or MWAB-UE IP address) included in Uplink NAS Transport is an example of an identifier that identifies the backhaul line within the backhaul system.

[0058] In step S403, AMF 30A sends Nsmf_PDUSession_CreateSMContext request(SmContextCreateData(dnn=Internet, n1SmMsg(PDU session establishment request), ueLocation, BH PDU session ID(or MWAB-UE IP address))) to SMF 30B.

[0059] In step S404, SMF 30B recognizes that the UE is hosted by MWAB-gNB based on the gNB ID and local information contained in ueLocation.

[0060] In step S405, based on the recognition in S404, SMF 30B decides to request PCF to secure BH resources.

[0061] In step S406, SMF 30B sends Npcf_SMPolicyControl_Create request(SmPolicyContextData(backhaulResourceRequest(BH PDU session ID(or MWAB-UE IP address)))) to PCF 30D.

[0062] In step S407, PCF 30D sends an Npcf_PolicyAuthorization_Update request (BH PDU session ID (or MWAB-UE IP address)) to BH 5GC PCF 60C.

[0063] In step S408, BH 5GC PCF 60C sends the Npcf_PolicyAuthorization_Update response to PCF 30D.

[0064] In step S409, PCF 30D sends Npcf_SMPolicyControl_Create response(SmPolicyDecision(backhaulResourceRequestResult=success)) to SMF 30B. Npcf_SMPolicyControl_Create response is an example of a response message that includes information indicating the success or failure of securing communication resources (for example, backhaulResourceRequestResult=success).

[0065] (Device Configuration) Next, an example of the functional configuration of the base station (NG-RAN 10), network node, and terminal (UE 20) that perform the processing and operations described above will be explained. The base station 10, network node, and terminal 20 include the functions to perform the embodiments described above. However, the base station 10, network node, and UE 20 may each have only some of the functions in the embodiments.

[0066] <Base Station and Network Nodes> Figure 6 shows an example of the functional configuration of a base station 10 and a network node. As shown in Figure 6, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Figure 6 is merely an example. The functional classifications and names of the functional units can be anything as long as they can perform the operation according to this embodiment. Note that the network node may have the same functional configuration as the base station 10. Furthermore, a network node having multiple different functions in the system architecture may be composed of multiple network nodes separated by function.

[0067] The transmitting unit 110 includes the function of generating a signal to be transmitted to the UE 20 or other network nodes and transmitting the signal by wire or wireless. The receiving unit 120 includes the function of receiving various signals transmitted from the UE 20 or other network nodes and obtaining information from the received signals, for example, information from a higher layer. A communication unit including the transmitting unit 110 and the receiving unit 120 may be configured.

[0068] The setting unit 130 stores pre-configured setting information and various setting information to be transmitted to the UE 20 in a storage device, and reads it from the storage device as needed.

[0069] The control unit 140 performs the processing described in the embodiment. The control unit 140 also performs processing related to communication with the UE 20. The signal transmission function in the control unit 140 may be included in the transmission unit 110, and the signal reception function in the control unit 140 may be included in the reception unit 120.

[0070] <UE> Figure 7 is a diagram showing an example of the functional configuration of UE 20 (terminal). As shown in Figure 7, UE 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Figure 7 is just one example. Any functional classification and functional unit names are acceptable as long as they enable the operation according to this embodiment.

[0071] The transmitting unit 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiving unit 220 wirelessly receives various signals and obtains signals from higher layers from the received physical layer signals. The receiving unit 220 also has the function of receiving control signals or reference signals transmitted from network nodes. A communication unit including the transmitting unit 210 and the receiving unit 220 may be configured.

[0072] The configuration unit 230 stores various configuration information received from network nodes by the receiving unit 220 in its storage device and reads it from the storage device as needed. The configuration unit 230 also stores pre-configured configuration information.

[0073] The control unit 240 performs the processing described in the embodiment. The signal transmission function in the control unit 240 may be included in the transmission unit 210, and the signal reception function in the control unit 240 may be included in the reception unit 220.

[0074] (Hardware Configuration) The block diagrams (Figures 6 and 7) used in the description of the above embodiments show functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may be realized by combining the one device or the multiple devices with software.

[0075] Functions include, but are not limited to, judgment, decision, determination, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, assumption, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission is called a transmitting unit or transmitter. In all cases, as mentioned above, the method of implementation is not particularly limited.

[0076] For example, the base station 10, network node, UE 20, etc. in one embodiment of the present disclosure may function as a computer that processes the wireless communication method of the present disclosure. Figure 8 is a diagram showing an example of the hardware configuration of the base station 10 and UE 20 according to one embodiment of the present disclosure. The network node may have a hardware configuration similar to that of the base station 10. The base station 10 and UE 20 described above may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0077] In the following explanation, the term "device" can be replaced with "circuit," "device," "unit," etc. The hardware configuration of base station 10 and UE 20 may include one or more of the devices shown in the figure, or it may be configured to omit some of the devices.

[0078] Each function in the base station 10 and UE 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and storage device 1002, which allows the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of data reading and writing in the storage device 1002 and auxiliary storage device 1003.

[0079] The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may consist of a central processing unit (CPU) that includes interfaces with peripheral devices, control devices, arithmetic units, registers, etc. For example, the control unit 140, control unit 240, etc., described above may be implemented by the processor 1001.

[0080] Furthermore, the processor 1001 reads programs (program code), software modules, or data from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002, and executes various processes accordingly. The program used is one that causes the computer to execute at least a part of the operations described in the above embodiment. For example, the control unit 140 of the base station 10 shown in Figure 6 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001. Also, for example, the control unit 240 of the UE 20 shown in Figure 7 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001. Although the above-described processes have been explained as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may also be transmitted from the network via a telecommunications line.

[0081] The storage device 1002 is a computer-readable recording medium and may consist of at least one of the following: ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), etc. The storage device 1002 may also be called a register, cache, main memory, etc. The storage device 1002 can store executable programs (program code), software modules, etc., for implementing a communication method according to one embodiment of the present disclosure.

[0082] The auxiliary storage device 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital multipurpose disk, a Blu-ray® disk), a smart card, flash memory (e.g., a card, a stick, a key drive), a floppy® disk, a magnetic strip, etc. The above-mentioned storage medium may also be a database, server, or other suitable medium that includes at least one of the storage device 1002 and the auxiliary storage device 1003.

[0083] The communication device 1004 is hardware (transmitting / receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, communication module, etc. The communication device 1004 may be configured to include, for example, a high-frequency switch, duplexer, filter, frequency synthesizer, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the transmitting and receiving antenna, amplifier section, transmitting and receiving section, transmission path interface, etc., may be implemented by the communication device 1004. The transmitting and receiving section may be implemented in a physically or logically separated manner, with a transmitting section and a receiving section.

[0084] The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, LED lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel).

[0085] Furthermore, each device, such as the processor 1001 and the storage device 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0086] Furthermore, the base station 10 and UE 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array), and some or all of each functional block may be realized by such hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0087] Figure 9 shows an example of the configuration of vehicle 2001. As shown in Figure 9, vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. Each aspect / embodiment described in this disclosure may be applied to a communication device mounted on vehicle 2001, for example, to the communication module 2013.

[0088] The drive unit 2002 consists of, for example, an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel, which is operated by the user.

[0089] The electronic control unit 2010 consists of a microprocessor 2031, memory (ROM, RAM) 2032, and communication ports (IO ports) 2033. Signals from various sensors 2021 to 2029 installed in the vehicle 2001 are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0090] Signals from various sensors 2021 to 2029 include current signals from current sensor 2021 for sensing motor current, front and rear wheel rotation speed signals acquired by rotation speed sensor 2022, front and rear wheel air pressure signals acquired by air pressure sensor 2023, vehicle speed signals acquired by vehicle speed sensor 2024, acceleration signals acquired by acceleration sensor 2025, accelerator pedal depression signals acquired by accelerator pedal sensor 2029, brake pedal depression signals acquired by brake pedal sensor 2026, shift lever operation signals acquired by shift lever sensor 2027, and detection signals acquired by object detection sensor 2028 for detecting obstacles, vehicles, pedestrians, etc.

[0091] The Information Service Unit 2012 consists of various devices for providing (outputting) various types of information such as driving information, traffic information, and entertainment information, including a car navigation system, audio system, speakers, television, and radio, and one or more ECUs that control these devices. The Information Service Unit 2012 uses information acquired from external devices via a communication module 2013, etc., to provide various multimedia information and multimedia services to the occupants of the vehicle 2001. The Information Service Unit 2012 may include input devices that accept input from the outside (e.g., keyboard, mouse, microphone, switch, button, sensor, touch panel, etc.) and output devices that perform output to the outside (e.g., display, speaker, LED lamp, touch panel, etc.).

[0092] The driver assistance system unit 2030 consists of various devices that provide functions to prevent accidents or reduce the driver's workload, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System)), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. The driver assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize driver assistance functions or autonomous driving functions.

[0093] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via its communication port. For example, the communication module 2013 sends and receives data via the communication port 2033 between the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, the microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021-29 provided in the vehicle 2001.

[0094] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with external devices. For example, it can send and receive various types of information with external devices via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station or a mobile station.

[0095] The communication module 2013 may transmit at least one of the following to an external device via wireless communication: signals from the various sensors 2021-2028 input to the electronic control unit 2010, information obtained based on said signals, and information based on input from an external source (user) obtained via the information service unit 2012. The electronic control unit 2010, the various sensors 2021-2028, the information service unit 2012, etc., may also be called input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include the information based on the above input.

[0096] The communication module 2013 receives various information (traffic information, signal information, inter-vehicle information, etc.) transmitted from an external device and displays it on the information service unit 2012 provided in the vehicle 2001. The information service unit 2012 may also be called an output unit, which outputs information (for example, outputs information to devices such as displays and speakers based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the various information received from the external device in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021-2029, etc., provided in the vehicle 2001.

[0097] <Note> (Note 1) A network node that performs session management, comprising: a receiving unit that receives a message from a network node that performs access and mobility management requesting the establishment of a PDU (Protocol Data Unit) session, which includes an identifier for a backhaul line in the backhaul system; a control unit that determines whether it is necessary to use the backhaul line; and a transmitting unit that transmits a policy decision request message to a network node that performs policy control, which includes the identifier and information requesting that the necessary communication resources be secured in the backhaul system.

[0098] (Note 2) The network node described in Note 1, wherein the message requesting the establishment of the PDU session includes a base station identifier and a destination network identifier, and the control unit determines that it is necessary to use the backhaul line if there is no network node with user plane functionality adjacent to the base station indicated by the base station identifier, or if the network node with user plane functionality does not support the connection corresponding to the destination network identifier.

[0099] (Note 3) The backhaul system is comprised of a 5G (5th Generation) system, and the backhaul line is configured based on a PDU session, as described in Note 1.

[0100] (Appendix 4) The network node as described in Appendix 1, wherein the identifier of the backhaul line is at least one of the following: a local IP address assigned to the termination point of the backhaul line, a session identifier defined within the backhaul system, or an IP address assigned to a device that has established a session within the backhaul system.

[0101] (Appendix 5) A first network node that performs policy management, comprising: a receiving unit that receives a message from a second network node that performs session management requesting a policy determination for a PDU (Protocol Data Unit) session, which includes an identifier for a backhaul line in the backhaul system and information requesting the acquisition of communication resources required by the backhaul system; a control unit that determines the communication quality for each QoS (Quality of Service) flow corresponding to the communication quality of the PDU session and determines the amount of communication resources that the backhaul system should request to satisfy the communication quality; and a transmitting unit that transmits a message to a third network node that performs policy management in the backhaul system requesting the securing of communication resources, which includes the identifier and the amount of communication resources, wherein the receiving unit receives a response message from the network node that performs policy management in the backhaul system, which includes information indicating whether the securing of the communication resources has been successful, and the control unit adjusts and determines the communication quality of the PDU session based on the communication resources secured by the backhaul system.

[0102] (Appendix 6) A base station using a backhaul line within a backhaul system, comprising: a receiving unit that receives a message from a terminal requesting the establishment of a PDU (Protocol Data Unit) session; and a base station that transmits a message requesting the establishment of a PDU session, including the identifier of the backhaul line, to a network node that performs access and mobility management.

[0103] The above configuration makes it possible to efficiently secure communication resources at the N3 interface between the base station (HgNB or MWAB gNB) and the core network, enabling the QoS intended by 5GS. As a result, stable data transfer is achieved even in communication environments using fixed access networks or BH 5GS.

[0104] Furthermore, the above configuration provides a mechanism for dynamically managing communication resources in conjunction with the fixed access network and BH 5GS. This automates the securing of necessary communication resources at the N3 interface, improving network efficiency. In particular, when Home UPF is selected, dynamic management becomes possible that takes into account conditions under which securing communication resources on the fixed access network is unnecessary, thus optimizing resources.

[0105] Furthermore, the above configuration mitigates the risk of bandwidth shortages in the N3 interface and provides a flexible and efficient solution for maintaining overall 5GS communication quality, and is compatible with a variety of communication environments, including home networks and mobile backhaul (BH) systems. This improves the operational efficiency of the 5G system.

[0106] (Supplement to Embodiments) Although these embodiments have been described above, the disclosed invention is not limited to these embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, substitutions, etc. Specific numerical examples have been used to facilitate understanding of the invention, but unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention, and matters described in two or more items may be combined as needed, and matters described in one item may be applied to matters described in another item (as long as they do not contradict each other). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical parts. The operation of multiple functional units may be physically performed by one part, or the operation of one functional unit may be physically performed by multiple parts. The processing procedures described in the embodiments may be rearranged as long as they do not contradict each other. For the convenience of explaining the processing, the base station 10 and UE 20 have been described using functional block diagrams, but such devices may be implemented in hardware, software, or a combination thereof. The software operated by the processor of the base station 10 according to this embodiment and the software operated by the processor of the UE 20 according to this embodiment may be stored in any suitable storage medium such as random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or other appropriate storage medium.

[0107] Furthermore, notification of information is not limited to the embodiments described herein and may be carried out by other means. For example, notification of information may be carried out by physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling), broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or combinations thereof. Also, RRC signaling may be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0108] Each aspect / embodiment described in this disclosure refers to LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (where x is, for example, an integer or decimal)), FRA (Future Radio Access), NR (new Radio), New radio access (NX), Future generation radio access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20 may apply to at least one system utilizing UWB (Ultra-WideBand), Bluetooth®, or other appropriate systems, and to next-generation systems extended, modified, created, or defined based thereon. Alternatively, multiple systems may be applied in combination (e.g., a combination of at least one of LTE and LTE-A with 5G).

[0109] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described herein may be reordered, provided they are consistent with each other. For example, the methods described herein present various step elements in an exemplary order and are not limited to that specific order.

[0110] In this specification, specific operations performed by the base station 10 may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having a base station 10, it is clear that various operations performed for communication with the UE 20 can be performed by the base station 10 and at least one of the other network nodes (for example, an MME or S-GW, but not limited to these). Although the above example illustrates the case where there is one other network node besides the base station 10, the other network node may be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0111] The information or signals described in this disclosure may be output from a higher layer (or lower layer) to a lower layer (or higher layer). They may also be input and output via multiple network nodes.

[0112] Input and output information may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information may be overwritten, updated, or appended to. Output information may be deleted. Input information may be transmitted to other devices.

[0113] The determination in this disclosure may be made by a value represented by one bit (0 or 1), by a Boolean value (true or false), or by a numerical comparison (for example, a comparison with a predetermined value).

[0114] Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name.

[0115] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0116] The information, signals, etc. described in this disclosure may be represented using any of the various different techniques. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0117] In addition, terms used in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and symbol may be a signal (signaling). Also, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, cell, frequency carrier, etc.

[0118] The terms “system” and “network” as used in this disclosure are interchangeable.

[0119] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information. For example, wireless resources may be indicated by an index.

[0120] The names used for the parameters described above are not restrictive in any way. Furthermore, the formulas and other expressions using these parameters may differ from those expressly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, and therefore, the various names assigned to these various channels and information elements are not restrictive in any way.

[0121] In this disclosure, terms such as "Base Station (BS)", "wireless base station", "base station equipment", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0122] A base station can accommodate one or more (e.g., three) cells. If a base station accommodates multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, each of which may also be provided with communication services by a base station subsystem (e.g., a Remote Radio Head (RRH)). The terms “cell” or “sector” refer to part or all of the coverage area of ​​at least one of the base station and / or base station subsystems that provide communication services in that coverage.

[0123] In this disclosure, the transmission of information by a base station to a terminal may be interpreted as the base station instructing the terminal to perform control or operation based on the information.

[0124] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0125] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or several other appropriate terms.

[0126] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body refers to a movable object, and its speed of movement is arbitrary. This also includes the case when the mobile body is stationary. The mobile body includes, but is not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcarts, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and items mounted on them. The mobile body may also be a mobile body that moves autonomously based on operation commands. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Furthermore, at least one of the base station and the mobile station may include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0127] Furthermore, the term "base station" in this disclosure may be interpreted as "user terminal." For example, the various aspects / embodiments of this disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple terminals (which may be called, for example, D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.). In this case, the terminal may have the functions that the base station has as described above. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, uplink channel, downlink channel, etc., may be interpreted as side channel.

[0128] Similarly, the term "user terminal" in this disclosure may be replaced with "base station." In this case, the base station may be configured to have the same functions as the user terminal described above.

[0129] As used in this disclosure, the terms “determining” and “determining” may encompass a wide variety of actions. “Determining” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, or inquiring (e.g., searching in a table, database, or other data structure), or ascertaining. “Determining” may also include receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, or accessing (e.g., accessing data in memory). Furthermore, "judgment" and "decision" can include considering something as having been "judged" or "decided" after resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment" and "decision" can include considering something as having been "judged" or "decided" after some action. Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0130] The terms “connected,” “coupled,” or any variation thereof, mean any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are “connected” or “coupled” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be reinterpreted as “access.” As used in this disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0131] The reference signal can also be abbreviated as RS (Reference Signal), and may be called a pilot depending on the applicable standard.

[0132] In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on."

[0133] Any reference to elements using the designations “first,” “second,” etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Accordingly, references to the first and second elements do not imply that only two elements may be employed, or that the first element must precede the second element in any way.

[0134] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0135] Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR.

[0136] In this disclosure, if articles are added through translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural.

[0137] In this disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "combine" may be interpreted similarly to "different."

[0138] Each aspect / embodiment described in this disclosure may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of specific information (e.g., notification that "X is") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification).

[0139] Although the present disclosure has been described in detail above, it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Therefore, the descriptions in the present disclosure are illustrative and not intended to be restrictive in any way.

[0140] 10 Base station 110 Transmitting unit 120 Receiving unit 130 Setting unit 140 Control unit 20 Terminal 210 Transmitting unit 220 Receiving unit 230 Setting unit 240 Control unit 30 Network node 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Front wheel 2008 Rear wheel 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 Rotation speed sensor 2023 Air pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driver assistance system unit 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port (I / O port)

Claims

1. A network node that performs session management, comprising: a receiving unit that receives a message from a network node that performs access and mobility management requesting the establishment of a PDU (Protocol Data Unit) session, which includes an identifier for a backhaul line in the backhaul system; a control unit that determines whether it is necessary to use the backhaul line; and a transmitting unit that transmits a policy decision request message to a network node that performs policy control, which includes the identifier and information requesting that the necessary communication resources be secured in the backhaul system.

2. The network node according to claim 1, wherein the message requesting the establishment of the PDU session includes a base station identifier and a destination network identifier, and the control unit determines that it is necessary to use the backhaul line if there is no network node with user plane functionality adjacent to the base station indicated by the base station identifier, or if the network node with user plane functionality does not support a connection corresponding to the destination network identifier.

3. The network node according to claim 1, wherein the backhaul system is comprised of a 5G (5th Generation) system, and the backhaul line is configured based on PDU sessions.

4. The network node according to claim 1, wherein the identifier of the backhaul line is at least one of the following: a local IP address assigned to the termination point of the backhaul line, a session identifier defined within the backhaul system, or an IP address assigned to a device that has established a session within the backhaul system.

5. A first network node that performs policy management, comprising: a receiving unit that receives a message from a second network node that performs session management requesting a policy determination for a PDU (Protocol Data Unit) session, which includes an identifier for a backhaul line in the backhaul system and information requesting the acquisition of communication resources required by the backhaul system; a control unit that determines the communication quality for each QoS (Quality of Service) flow corresponding to the communication quality of the PDU session and determines the amount of communication resources that should be requested by the backhaul system to satisfy the communication quality; and a transmitting unit that sends a message to a third network node that performs policy management in the backhaul system requesting the securing of communication resources, which includes the identifier and the amount of communication resources, wherein the receiving unit receives a response message from the network node that performs policy management in the backhaul system, which includes information indicating whether the securing of the communication resources has been successful, and the control unit adjusts and determines the communication quality of the PDU session based on the communication resources secured by the backhaul system.

6. A base station using a backhaul line within a backhaul system, comprising: a receiving unit that receives a message from a terminal requesting the establishment of a PDU (Protocol Data Unit) session; and a base station that transmits a message requesting the establishment of a PDU session, including the identifier of the backhaul line, to a network node that performs access and mobility management.

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