Session establishment method, device, equipment and storage medium

Abstract

The present application discloses a session establishment method, apparatus, device and storage medium, which belongs to the field of communication technology. The method includes a relay device sending a first session establishment request to a first core network device, the first session establishment request is used to request the establishment of a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC. The technical solution provided by the embodiment of the present application sends a session establishment request to the core network device through a relay device, and the session establishment request carries an RSC corresponding to the service attribute. Since the RSC is a service code, it is not easy to crack and leak. Compared with directly carrying service attributes in the session establishment request, which may cause the leakage of service attributes and affect the system security, the embodiment of the present application ensures that the core network clearly defines the service attributes, and also ensures the privacy protection of the service attributes, thereby improving the security of the system.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and in particular to a session establishment method, apparatus, device and storage medium. Background Art

[0002] 3GPP (3rd Generation Partnership Project) introduced the concept of relay communication in the R13 (Release 13) ProSe (Proximity Service) architecture.

[0003] Relay communication refers to UE (User Equipment)-to-Network (terminal equipment connected to the network) based on IP (Internet Protocol) layer relay. That is, the Remote UE (remote device) accesses the network through the Relay UE (relay device). Among them, the Relay UE assumes the function of IP layer relay, transmits data between the Remote UE and the network to establish a communication connection between the Remote UE and the network. Exemplarily, the network includes access network equipment and core network equipment. The Relay UE sends data from the Remote UE to the access network equipment, and can be further sent by the access network equipment to the core network equipment; or, the access network equipment sends data from the core network equipment to the Relay UE, and then the Relay UE sends data from the access network equipment to the Remote UE.

[0004] However, in order to transmit data between the Remote UE and the network, the Relay UE needs to establish a suitable PDU (Protocol Data Unit) session. For different types of services that the Remote UE needs to carry out, how to establish a PDU session corresponding to the service type needs further discussion and research. Summary of the invention

[0005] The embodiment of the present application provides a session establishment method, apparatus, device and storage medium. The technical solution is as follows:

[0006] On the one hand, an embodiment of the present application provides a session establishment method, which is applied to a relay device, and the method includes:

[0007] A first session establishment request is sent to a first core network device, where the first session establishment request is used to request establishment of a PDU session between the relay device and a DN (Date Network), and the first session establishment request includes a first RSC (Relay Service Code).

[0008] On the other hand, an embodiment of the present application provides a session establishment method, which is applied to a first core network device, and the method includes:

[0009] A first session establishment request is received from a relay device, where the first session establishment request is used to request establishment of a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0010] On the other hand, an embodiment of the present application provides a session establishment method, which is applied to a second core network device, and the method includes:

[0011] receiving a second session establishment request from a first core network device, where the second core network device is selected by the first core network device based on the first RSC;

[0012] According to the second session establishment request, a PDU session is established between the relay device and the DN.

[0013] On the other hand, an embodiment of the present application provides a session establishment device, which is arranged in a relay device, and the device includes:

[0014] The first request sending module is used to send a first session establishment request to the first core network device, wherein the first session establishment request is used to request to establish a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0015] In another aspect, an embodiment of the present application provides a session establishment device, which is arranged in a first core network device, and the device includes:

[0016] The first request receiving module is used to receive a first session establishment request from a relay device, wherein the first session establishment request is used to request to establish a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0017] In another aspect, an embodiment of the present application provides a session establishment device, which is arranged in a second core network device, and the device includes:

[0018] A second request receiving module, configured to receive a second session establishment request from a first core network device, where the second core network device is selected by the first core network device based on the first RSC;

[0019] A session establishing module is used to establish a PDU session between the relay device and the DN according to the second session establishment request.

[0020] In another aspect, an embodiment of the present application provides a relay device, the relay device comprising: a processor, and a transceiver connected to the processor; wherein:

[0021] The transceiver is used to send a first session establishment request to the first core network device, where the first session establishment request is used to request to establish a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0022] In another aspect, an embodiment of the present application provides a core network device, the network device comprising: a processor, and a transceiver connected to the processor; wherein:

[0023] The transceiver is used to receive a first session establishment request from a relay device, where the first session establishment request is used to request to establish a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0024] In another aspect, an embodiment of the present application provides a core network device, the network device comprising: a processor, and a transceiver connected to the processor; wherein:

[0025] The transceiver is configured to receive a second session establishment request from a first core network device, where the second core network device is selected by the first core network device based on the first RSC;

[0026] The processor is used to establish a PDU session between the relay device and the DN according to the second session establishment request.

[0027] On the other hand, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. The computer program is used to be executed by a processor of a relay device to implement the above-mentioned relay device side session establishment method.

[0028] On the other hand, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. The computer program is used to be executed by a processor of a core network device to implement the session establishment method on the first core network device side as described above.

[0029] On the other hand, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. The computer program is used to be executed by a processor of a core network device to implement the above-mentioned second core network device side session establishment method.

[0030] On the other hand, an embodiment of the present application provides a chip, which includes a programmable logic circuit and / or program instructions. When the chip runs on a relay device, it is used to implement the above-mentioned relay device side session establishment method.

[0031] On the other hand, an embodiment of the present application provides a chip, which includes a programmable logic circuit and / or program instructions. When the chip runs on a core network device, it is used to implement the session establishment method on the first core network device side as mentioned above.

[0032] On the other hand, an embodiment of the present application provides a chip, which includes a programmable logic circuit and / or program instructions. When the chip runs on a core network device, it is used to implement the above-mentioned second core network device side session establishment method.

[0033] On the other hand, an embodiment of the present application provides a computer program product, which, when executed on a relay device, enables a computer to execute the above-mentioned method for establishing a session on the relay device side.

[0034] On the other hand, an embodiment of the present application provides a computer program product, which, when executed on a core network device, enables a computer to execute the above-mentioned first core network device side session establishment method.

[0035] On the other hand, an embodiment of the present application provides a computer program product, which, when executed on a core network device, enables a computer to execute the above-mentioned second core network device side session establishment method.

[0036] The technical solution provided by the embodiments of the present application may have the following beneficial effects:

[0037] A session establishment request is sent to a core network device through a relay device. The session establishment request carries an RSC corresponding to the service attributes. Since the RSC is a service code, it is not easy to crack or leak. Compared with directly carrying service attributes in a session establishment request, which may cause leakage of service attributes and affect system security, the embodiment of the present application ensures privacy protection for service attributes while ensuring that the core network clearly defines the service attributes, thereby improving the security of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 is a schematic diagram of a system architecture provided by an embodiment of the present application;

[0040] Figure 2 is a schematic diagram of the system architecture of an EPS system provided by an embodiment of the present application;

[0041] Figure 3 is a schematic diagram of the system architecture of a 5GS system provided by an embodiment of the present application;

[0042] Figure 4 is a schematic diagram of a system architecture of a 5GS system provided by another embodiment of the present application;

[0043] Figure 5 is a schematic diagram of a relay communication system provided by an embodiment of the present application;

[0044] Figure 6 This is a flowchart of a remote device accessing a network and obtaining an IP service provided by an embodiment of the present application;

[0045] Figure 7 This is a flowchart of a relay device establishing a PDU session provided by an embodiment of the present application;

[0046] Figure 8 is a flow chart of a session establishment method provided by an embodiment of the present application;

[0047] Fig. 9 is a flowchart of a session establishment method provided by another embodiment of the present application;

[0048] Fig.10 is a flowchart of a session establishment method provided by yet another embodiment of the present application;

[0049] Fig.11 is a flowchart of a session establishment method provided by another embodiment of the present application;

[0050] Fig.12 is a block diagram of a session establishment device provided by an embodiment of the present application;

[0051] Fig.13 is a block diagram of a session establishment device provided by another embodiment of the present application;

[0052] Fig.14 is a block diagram of a session establishment device provided by yet another embodiment of the present application;

[0053] Fig.15 is a block diagram of a session establishment device provided by another embodiment of the present application;

[0054] Fig.16 is a block diagram of a session establishment device provided by another embodiment of the present application;

[0055] Fig.17 is a structural block diagram of a relay device provided by an embodiment of the present application;

[0056] Fig.18 It is a structural block diagram of a core network device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0057] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0058] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. A person of ordinary skill in the art can appreciate that with the evolution of the network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0059] The technical solution provided in the embodiments of the present application can be applied to various communication systems, for example: GSM (Global System of Mobile Communication) system, CDMA (Code Division Multiple Access) system, ECDMA (Wideband Code Division Multiple Access) system, GPRS (General Packet Radio Service), LTE (Long Term Evolution) system, FDD (Frequency Division Duplex) system, TDD (Time Division Duplex) system, UMTS (Universal Mobile Telecommunication System), WiMAX (Worldwide Interoperability for Microwave Access) communication system, 5GS or New Radio (NR) system, or other subsequent evolution systems.

[0060] Please refer to Figure 1 , which shows a schematic diagram of the system architecture of a communication system provided by an embodiment of the present application. Figure 1 As shown, the system architecture 100 may include: a terminal device 10 , an access network device 20 and a core network device 30 .

[0061] The terminal device 10 may refer to a UE, an access terminal, a user unit, a user station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a wireless communication device, a user agent or a user device. Optionally, the terminal device may also be a cellular phone, a cordless phone, a SIP (Session Initiation Protocol) phone, a WLL (Wireless Local Loop) station, a PDA (Personal Digital Assistant), a handheld device with a wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a 5GS or a terminal device in a future evolved PLMN (Public Land Mobile Network), etc., and the embodiments of the present application are not limited to this.

[0062] The access network device 20 is a device deployed in the access network to provide wireless communication functions for terminal devices. The access network device 20 may include various forms of macro base stations, micro base stations, relay stations, access points, etc. In systems using different wireless access technologies, the names of devices with access network device functions may be different. For example, in the 5G (5th-Generation, fifth-generation mobile communication) NR (New Radio, new air interface) system, it is called gNodeB or gNB, and in the EPS (Evolved Packet System, evolved packet system) system, the access network device can be called eNodeB (EvolvedNodeB, evolved base station). With the evolution of communication technology, the name "access network device" may change. For the convenience of description, in the embodiments of the present application, the above-mentioned devices that provide wireless communication functions for terminal devices are collectively referred to as access network devices.

[0063] The core network device 30 refers to a device that can provide session management, mobility relations, policy management, security authentication and other functions for the terminal device. In an embodiment of the present application, the core network device 30 may include a first core network device and a second core network device, wherein the first core network device is responsible for the access management and mobility management of the terminal device, and the second core network device is responsible for the session management of the terminal device. Exemplarily, in a 5GS system, the first core network can be implemented as an AMF (Core Access and Mobility Management Function), and the second core network device can be implemented as an SMF (Session Management Function); in an EPS system, the first core device can be implemented as an MME (Mobility Management Entity), and the second core network device can be implemented as an SGW (Serving Gateway).

[0064] In one example, if Figure 1 As shown, the terminal device includes a remote terminal device 12 and a relay terminal device 14. The relay device 14 can perform data transmission with the remote device 12 to establish a communication connection between the remote device 12 and the access network device 20 and the core network device 30. For example, the relay device 14 sends data from the remote device 12 to the access network device 20, and the access network device 20 can further send the data to the core network device 30; or, the access network device 20 sends the data from the core network device 30 to the relay device 14, and then the relay device 14 sends the data from the access network device 20 to the remote device 12.

[0065] Figure 2 FIG. 1 is a schematic diagram showing the system architecture of the EPS system provided in the embodiment of the present application. Figure 2 As shown, the system architecture may include the following network entities:

[0066] 1. EUTRAN: A network composed of multiple eNodeBs, which implements wireless physical layer functions, resource scheduling and wireless resource management, wireless access control, and mobility management functions. eNodeBs can be connected through the X2 interface, which can be used to transmit data during the X2-based handover process. The eNodeB is connected to the SGW through the user plane interface SI-U, and uses GTP-U (General Packet Radio System General Tunneling Protocol User Plane) to transmit user data: it is connected to the MME through the control plane interface SI-E, and uses the SI-AP protocol to implement functions such as wireless access bearer control.

[0067] 2. MME: Mainly responsible for all control plane functions of user and session management, including NAS (Non-Access-Stratum) signaling and security, management of tracking area lists, selection of P-GW (Packet Data Network Gateway) and SGW, etc.

[0068] 3. SGW: Mainly responsible for data transmission, forwarding and route switching of user equipment, and serves as the local mobility anchor point when the user equipment switches between eNodeBs (for each user equipment, there is only one SGW serving it at each time).

[0069] 4. P-GW: As the anchor point of PDN (Packet Data Network) connection, it is responsible for IP address allocation for user equipment, data packet filtering, rate control, generation of billing information, etc.

[0070] 5. SGSN (Serving GPRS supporting Node): It is the access node of 2G access network GERAN (GSM / EDGE Radio Access Network), 3G access network UTRAN (Universal Terrestrial Radio Access Network) and EPS core network EPC, responsible for establishing bearers and forwarding data from GERAN, UTRAN to EPC.

[0071] 6. HSS (Home Subscriber Server): stores the subscription data of mobile users.

[0072] 7. PCRF (Policy and Charging Rules Function): responsible for charging management and policy control, including PCC (Policy and Charging Control) rules and QoS (Quality of Service) rules.

[0073] Figure 3 FIG. 1 is a schematic diagram showing the system architecture of the 5GS system provided in the embodiment of the present application. Figure 3 As shown, the system architecture 200 may include: UE, RAN (Radio Access Network), Core (core network) and DN. Among them, UE, RAN, Core are the main components of the architecture. Logically, they can be divided into two parts: user plane and control plane. The control plane is responsible for the management of the mobile network, and the user plane is responsible for the transmission of service data. In the figure, the NG2 reference point is located between the RAN control plane and the Core control plane, the NG3 reference point is located between the RAN user plane and the Core user plane, and the NG6 reference point is located between the Core user plane and the data network.

[0074] UE: It is the entry point for mobile users to interact with the network. It can provide basic computing and storage capabilities, display service windows to users, and accept user operation input. UE will use the next generation air interface technology to establish signal and data connections with RAN, thereby transmitting control signals and service data to the mobile network.

[0075] RAN: Similar to the base station in the traditional network, it is deployed close to the UE, provides network access for authorized users in a specific area, and can use transmission tunnels of different qualities to transmit user data according to the user level and business requirements. RAN can manage its own resources, use them reasonably, provide access services to UE on demand, and forward control signals and user data between UE and the core network.

[0076] Core: Responsible for maintaining the subscription data of the mobile network, managing the network elements of the mobile network, and providing the UE with functions such as session management, mobility management, policy management, and security authentication. When the UE is attached, it provides the UE with network access authentication; when the UE has a service request, it allocates network resources to the UE; when the UE moves, it updates the network resources for the UE; when the UE is idle, it provides the UE with a fast recovery mechanism; when the UE is detached, it releases network resources for the UE; when the UE has service data, it provides the UE with data routing functions, such as forwarding uplink data to the DN; or receiving UE downlink data from the DN, forwarding it to the RAN, and then sending it to the UE.

[0077] DN: It is a data network that provides business services to users. Generally, the client is located in the UE and the server is located in the data network. The data network can be a private network, such as a local area network, or an external network that is not controlled by the operator, such as the Internet, or a proprietary network jointly deployed by operators, such as for configuring IMS (IP Multimedia Core Network Subsystem) services.

[0078] Figure 4 is Figure 3 The detailed architecture is determined on the basis of the core network, in which the core network user plane includes UPF (User Plane Function); the core network control plane includes AUSF (Authentication Server Function), AMF, SMF, NSSF (Network Slice Selection Function), NEF (Network Exposure Function), NRF (NF Repository Function), UDM (Unified Data Management), PCF (Policy Control Function), AF (Application Function). The functions of these functional entities are as follows:

[0079] UPF: performs user data packet forwarding according to the routing rules of SMF;

[0080] AUSF: performs security authentication of UE;

[0081] AMF: UE access management and mobility management;

[0082] SMF: UE session management;

[0083] NSSF: selects network slices for UE;

[0084] NEF: Opens network functions to third parties via northbound APIs.

[0085] NRF: Provides storage and selection functions for network function entity information for other network elements;

[0086] UDM: User contract context management;

[0087] PCF: User Policy Management;

[0088] AF: User Application Management.

[0089] exist Figure 4 In the architecture shown, the N1 interface is the reference point between the UE and the AMF; the N2 interface is the reference point between the RAN and the AMF, which is used for sending NAS messages, etc.; the N3 interface is the reference point between the RAN and the UPF, which is used for transmitting user plane data, etc.; the N4 interface is the reference point between the SMF and the UPF, which is used for transmitting information such as the tunnel identification information of the N3 connection, data cache indication information, and downlink data notification messages; the N6 interface is the reference point between the UPF and the DN, which is used for transmitting user plane data, etc.

[0090] It should be noted that Figure 3 and Figure 4 The interface name between the various network elements is only an example. The name of the interface in a specific implementation may be other names, and the embodiments of the present application do not specifically limit this. Figure 3 and Figure 4 The names of the various network elements (such as SMF, AF, UPF, etc.) included in are only examples and do not limit the functions of the network elements themselves. In 5GS and other future networks, the above-mentioned network elements may also have other names, and the embodiments of the present application do not specifically limit this. For example, in a 6G network, some or all of the above-mentioned network elements may use the terminology in 5G, or may use other names, etc., which are uniformly explained here and will not be repeated below. In addition, it should be understood that the name of the message (or signaling) transmitted between the above-mentioned network elements is only an example and does not constitute any limitation on the function of the message itself.

[0091] Please refer to Figure 5 , which shows a schematic diagram of a relay communication system provided by an embodiment of the present application. Figure 5 The relay communication system shown mainly includes three parts: a wireless subsystem part, an EPC (Evolved Packet Core) part, and a short distance communication service part.

[0092] The wireless subsystem, namely EUTRAN, includes one or more eNodeBs, which can also be called the access network equipment part in the EPS system.

[0093] The EPC part includes the above-mentioned HSS, MME, SGW, PGW, etc.

[0094] The short-distance communication service part, that is, the ProSe architecture part, includes PF (ProSe Function, short-distance communication service function), PAS (ProSe Application Server, short-distance communication application server), relay device (RelayUE), and remote device (Remote UE). Among them: PF: used to authorize the short-distance communication of terminal devices, provide discovery assistance between terminal devices, etc.; PAS: used to provide specific short-distance communication service support; Relay UE: used to provide relay access support for Remote UE; Remote UE: used to access the network through Relay UE and obtain IP (Internet Protocol, the protocol for interconnection between networks) services. In an example, Figure 5 As shown, PA (ProSe Application, short distance communication service) is installed in both the Relay UE and the Remote UE.

[0095] Based on the above Figure 5 The relay communication system architecture shown in Figure 6 The flowchart of how a remote device accesses the network through a relay device and obtains IP services is shown. Figure 6 As shown in the figure, the process of remote device accessing the network includes the following steps:

[0096] Step 610: The relay device attaches to the network and / or the relay device requests to establish a PDN connection. The relay device may request to establish a PDN (Public Data Network) connection while attaching to the network.

[0097] Step 620: The remote device discovers the relay device. In one example, when discovering the relay device, the remote device uses the APN (Access Point Name) supported by the relay device as reference information.

[0098] Step 630: The remote device requests the relay device to establish a one-to-one communication. The remote device may request the relay device to establish a one-to-one (One-2-One) communication through the PC5 interface. Optionally, the request sent by the remote device carries an APN. Optionally, while executing step 630 or after executing step 630, step 632 may also be executed, and the relay device requests to establish a new PDN connection.

[0099] Step 640: The relay device allocates an IP address to the remote device. The embodiment of the present application does not limit the content of the IP address. Optionally, the IP address is a private IPv4 address or an IPv6 prefix.

[0100] Step 650: The relay device sends a remote terminal report to the MME. Optionally, the remote terminal report carries an identifier of the remote device (such as Remote UE ID (Identifier)), an IP address, etc.

[0101] Step 660, MME sends a remote terminal report to PGW. After receiving the remote terminal report from the relay device, MME can send the remote terminal report to PGW, so that PGW can store the information of the remote device locally. PGW can use this information to gate the uplink and downlink data of the remote device, that is, whether to allow the transmission of uplink and downlink data. Optionally, after step 660, it also includes: the remote device sends uplink IP data, or receives downlink IP data, the IP data passes through the relay device, and the IP data is carried in the PDN connection for relay established by the relay device for the remote device.

[0102] From the above step 630, it can be seen that in order to transmit the relay data of the remote device, the relay device needs to use a suitable PDU session, and which PDU session to use to transmit the relay data is determined by the relay device. Usually, during the establishment of the PDU session, the relay device determines the parameters required to establish the PDU session according to the URSP (UE path selection policy) configured by the network. Please refer to Figure 7 , which shows a flow chart of a relay device establishing a PDU session provided by an embodiment of the present application. Figure 7 As shown, the process includes the following steps:

[0103] Step 701, the relay device sends a session establishment request message to the AMF. After registering with the AMF entity, the relay device (Relay UE) sends a session establishment request message to the AMF entity, and the session establishment request message is used to request the establishment of a PDU session. In an example, the session request establishment message includes at least one of the following: S-NSSAI (session management-network slice selection assistance information) corresponding to the PDU session, DNN (Date Network Name) corresponding to the PDU session, PDU session identifier, request type (request type), N1SM information (N1session management information), and PDU type.

[0104] Step 702: AMF selects SMF. After receiving the session establishment request message, the AMF entity may select an SMF entity according to certain rules.

[0105] Step 703, AMF sends an SM request message to SMF. After selecting the SMF entity, the AMF entity may send an SM (Session Management) request message to the SMF entity. Optionally, the SM request message includes at least one of the following: subscriber permanent ID, DNN, S-NSSAI, PDU session ID, N1SM information, user location information, and access technology type.

[0106] Step 704: SMF sends a subscription data request message to UDM. If the SMF entity has not obtained the SM-related subscription information of RelayUE from the UDM entity, the SMF entity needs to send a subscription data request message to the UDM entity to obtain the subscription data. In one example, the subscription data request message includes at least one of the following: subscription identifier (subscriber permanentID), DNN.

[0107] Step 705, UDM sends subscription data to SMF. After receiving the subscription data request message, the UDM entity may send a subscription data response message to the SMF entity. In one example, the subscription data response message includes subscription information. The SMF may then perform an authorization check on the subscription information. If the SMF entity confirms that the authorization check fails, it may send a NAS (Non Access Stratum) signaling to the Relay UE, which is used to indicate the rejection of the Relay UE's session establishment request.

[0108] Step 706, SMF completes the authorization / authentication of the establishment of the PDU session. In the case where the SMF entity needs to authorize / authenticate the establishment of the PDU session, the SMF entity needs to select the UPF entity according to certain rules, and then the SMF entity triggers the authorization / authentication of the establishment of the PDU session to complete the authorization / authentication of the establishment of the PDU session.

[0109] Step 707: SMF selects PCF. In case dynamic PCC (Policy Control and Charging) deployment is required, the SMF entity needs to select the PCF entity according to certain rules.

[0110] Step 708: SMF obtains PCC rules. The SMF entity sends a PDU-CAN (Controller Area Network) session establishment request to the selected PCF entity, thereby obtaining the PCC rules corresponding to the PDU session.

[0111] Step 709, SMF selects UPF. If the SMF entity does not select UPF in step 706, then at this time, the SMF entity can select a UPF entity.

[0112] Step 710, SMF initiates the PDU-CAN session establishment process. When dynamic PCC is deployed and the PDU-CAN session establishment process has not been executed, the SMF entity can initiate the PDU-CAN session establishment process to the PCF entity, and then the SMF entity obtains the default PCC rules from the PCF entity. When the request type sent by the Relay UE indicates that the PDU session requested to be established is an existing PDU session, the SMF entity initiates the PDU-CAN session modification process, and the SMF entity sends the allocated Relay UE IP address to the PCF entity.

[0113] Step 711, SMF initiates N4 session establishment / modification process to UPF. When the request type is the initial request type, the SMF entity initiates N4 session establishment process to the UPF entity; otherwise, the SMF entity initiates N4 session modification process to the UPF entity. Optionally, the SMF entity can also provide packet detection, reporting rules and CN tunnel information (tunnelinfo) to the UPF entity.

[0114] Step 712: UPF sends an N4 session establishment / modification response message to SMF. After receiving the initiation request from the SMF entity, the UPF entity may send an N4 session establishment / modification response message to the SMF entity.

[0115] Step 713: SMF sends an SM response message to AMF. In one example, the SM response message includes at least one of the following: a cause value (cause), N2 reference point session management information (N2SM information), N1SM information, etc.

[0116] Step 714: AMF sends an N2PDU session request message to RAN. In one example, the N2PDU session request message includes at least one of the following: N2SM information, NAS message, etc.

[0117] Step 715: RAN sends an RRC connection reconfiguration message to the relay device. The RAN entity may send an RRC (Radio Resource Control) connection reconfiguration message to the Relay UE, and the RAN entity allocates necessary RAN resources according to QoS (Quality of Service) rules. Optionally, the RAN entity may also forward a NAS message to the Relay UE.

[0118] Step 716: The relay device sends an RRC connection reconfiguration response message to the RAN. After receiving the RRC connection reconfiguration message from the RAN entity, the relay UE may send an RRC connection reconfiguration response message to the RAN entity.

[0119] Step 717: RAN sends an N2PDU session establishment response message to AMF. In one example, the N2PDU session response message includes at least one of the following: a PDU session identifier, a cause value, and an N2SM message.

[0120] Step 718: AMF sends an SM request message to SMF. The SM request message includes the N2SM message in step 717 above. Then, the AMF entity can forward the N2SM message from the RAN entity to the SMF entity.

[0121] Step 719, SMF sends an N4 session establishment / modification request message to UPF. If the N4 session is not established, the SMF entity can send an N4 session establishment message to the UPF entity; if the N4 session is established, the SMF entity can send an N4 session modification message to the UPF entity to update the access network (AN) tunnel information and the core network (CN) tunnel information.

[0122] Step 720: UPF sends an N4 session establishment / modification response message to SMF. Upon receiving the N4 session establishment / modification message, the UPF entity may send a corresponding N4 session establishment / modification response message to the SMF entity.

[0123] Step 721, SMF sends an SM response message to AMF. In one example, the SM response message includes a cause value.

[0124] Step 722: SMF sends an IPv6 Router Advertisement message to UPF. In one example, the IPv6 Router Advertisement message includes an IPv6 address prefix allocated by the SMF entity.

[0125] Step 723, SMF releases user plane resources. In the case where the PDU session is triggered by 3GPP or non-3GPP handover, the SMF entity also needs to release the user plane resources on the original access side.

[0126] Step 724, SMF triggers the unified data management registration service network function service. If the SMF entity identifier is not included in step 705, SMF needs to trigger the unified data management registration service network function service, so that the SMF entity interacts with the PCF entity and the UDM entity for service requests. The service request includes the address of the SMF entity, the identifier of the SMF entity that the DNN and UDM entity need to save, the address of the SMF entity, the associated DNN, etc.

[0127] As can be seen from the above description, in order to transmit data between RemoteUE and the network, RelayUE needs to establish a suitable PDU session. For the different types of services that RemoteUE needs to carry out, there is no relevant mechanism in the relevant technology to establish a PDU session corresponding to the service type. Based on this, an embodiment of the present application provides a session establishment method. The technical solution of the present application is introduced and explained through several exemplary embodiments below.

[0128] Please refer to Figure 8 , which shows a flow chart of a session establishment method provided by an embodiment of the present application, which can be applied to Figure 1 In the system architecture shown, the method may include the following steps:

[0129] Step 810: The relay device sends a first session establishment request to the first core network device. The first session establishment request is used to request to establish a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0130] When there is a need for data transmission between the relay device (Relay UE) and the DN, a PDU session can be established between the relay device and the DN, that is, a data transmission channel between the relay device and the DN is established. To this end, the relay device sends a first session establishment request to the first core network device, and the first session establishment request is used to request the establishment of a first PDU session. Optionally, the first core network device is implemented as the above-mentioned AMF (or referred to as "AMF entity", "AMF network element", etc.); or, in subsequent technical evolution, it is implemented as other core network devices with device access management and mobility management functions.

[0131] In the embodiment of the present application, the first session establishment request includes a first RSC. RSC (Relay Service Code) corresponds to the service attributes requested by the device. Compared with directly carrying the service attributes in the session establishment request, which may cause the leakage of service attributes and affect the system security, the embodiment of the present application carries the RSC corresponding to the service attributes in the session establishment request. While ensuring that the core network clearly defines the service attributes, it also ensures the privacy protection of the service attributes and improves the security of the system. Optionally, the first session establishment request is the session establishment request message in the above step 701, so the difference between step 810 and the above step 701 is that the first session establishment request in step 810 includes the first RSC.

[0132] Optionally, there is a one-to-one correspondence between RSC and service attributes, that is, one RSC corresponds to one service attribute. Among them, the service attribute refers to the attribute corresponding to the service requested by the device. Optionally, the service attribute includes at least one of the following: DNN information, Slice information, session type information, PLMN information, QoS information, etc. The embodiment of the present application does not limit the method for determining the first RSC. Optionally, the first RSC is determined by the remote device (Remote UE) and sent to the relay device. For example, when the remote device needs to initiate a service and wants to find a relay device for relay communication, the remote device needs to first determine the first RSC according to the service it wants to establish, and send the determined first RSC to the relay device; or, the first RSC is preset in the relay device. For example, corresponding to a certain relay device, assuming that it can only initiate a specific type of service, the RSC corresponding to the service it initiates may also be fixed, so that the RSC can be preset in the relay device.

[0133] The first core network device receives the first session establishment request, and parses the first session establishment request to obtain the first RSC. Since there are multiple core network devices (or called "entities", "network elements", etc.) that can establish PDU sessions in the core network system architecture, each core network device supports different service attributes. For example, some core network devices support DNN information, and some core network devices support session type information. Therefore, different core network devices are required to establish PDU sessions for different service attributes. The following describes the process of the first core network device selecting a suitable core network device based on the first RSC to establish a PDU session.

[0134] In one example, if Fig. 9 As shown, after the above step 810, the following steps are also included:

[0135] Step 820: The first core network device selects a second core network device according to the first RSC, and the second core network device is used to establish a PDU session.

[0136] The second core network device is a core network device used to establish a PDU session. Optionally, the second core network device is implemented as an SMF; or, in subsequent technical evolution, it is implemented as other core network devices with device session management functions. The selection basis of the second core network device includes the first RSC. The first core network device selects the second core network device corresponding to the service attribute according to the first RSC to establish the PDU session, so that the established PDU session meets the service requirements of the remote device. Optionally, in addition to selecting the second core network device according to the first RSC, the first core network device can also select the second core network device according to other information, such as the rules for selecting the second core network device mentioned in the relevant technology. For the specific selection process of the second core network device, please refer to the following embodiment, which will not be repeated here. Optionally, the first core network device selects the second core network device as the above step 702, so the difference between step 820 and the above step 702 is that in step 820, the basis for the first core network device to select the second core network device includes the first RSC.

[0137] Step 830: The first core network device sends a second session establishment request to the second core network device.

[0138] After the first core network device selects a suitable second core network device, a second session establishment request can be sent to the second core network device to request the establishment of a PDU session between the relay device and the DN. The embodiment of the present application does not limit the content of the second session establishment request. Optionally, the second session establishment request includes a first RSC; or, the second session establishment request includes session parameter information related to the PDU session requested to be established. The embodiment of the present application does not limit the content of the first session establishment request and the second session establishment request. Optionally, the content of the first session establishment request and the second session establishment request are the same, that is, the first core network device forwards the first session establishment request received from the relay device to the second core network device; or, the content of the first session establishment request is different from the content of the second session establishment request, that is, the first core network device performs some processing on the content of the first session establishment request received from the relay device to obtain a second session establishment request, and sends the second session establishment request to the second core network device.

[0139] Step 840: The second core network device establishes a PDU session between the relay device and the DN according to the second session establishment request.

[0140] After receiving the second session establishment request, the second core network device parses the second session establishment request to obtain some parameter information, and then establishes the PDU session between the relay device and the DN according to the parameter information obtained by parsing. For an introduction to the process of the second core network device establishing a PDU session, please refer to the following embodiment, which will not be described in detail here.

[0141] Step 850: The first core network device sends a first session establishment response to the relay device, where the first session establishment response is used to indicate that the PDU session establishment is complete.

[0142] After the second core network device establishes the PDU session, it can notify the first core network device that the PDU session establishment is complete. The embodiment of the present application does not limit the manner in which the second core network device notifies the first core network device that the PDU session establishment is complete. Optionally, the second core network device carries a notification message in the SM response message sent to the first core network device in the above step 713, and the notification message is used to indicate that the PDU session establishment is complete; or, the second core network device sends a notification message to the first core network device alone, and the notification message is used to indicate that the PDU session establishment is complete.

[0143] After receiving the notification that the PDU session is established, the first core network device sends a first session establishment response to the relay device. The first session establishment response is used to indicate that the PDU session is established, so that the data transmission channel between the relay device and the DN is established. The embodiment of the present application does not limit the carrying method of the first session establishment response. Optionally, the first core network device sends the first session establishment response to the relay device alone to notify the relay device that the PDU session is established; or, the first core network device carries the first session establishment response in the RRC connection reconfiguration message sent to the relay device in the above step 715 to notify the relay device that the PDU session is established. Optionally, the above-mentioned first session establishment response includes a first RSC, so that the relay device can clearly understand the service or RSC corresponding to the first session establishment response.

[0144] To sum up, the technical solution provided by the embodiment of the present application sends a session establishment request to the core network device through a relay device. The session establishment request carries an RSC corresponding to the service attributes. Since the RSC is a service code, it is not easy to crack and leak. Compared with directly carrying service attributes in the session establishment request, which may cause the leakage of service attributes and affect the system security, the embodiment of the present application ensures that the core network clearly defines the service attributes while also ensuring the privacy protection of the service attributes, thereby improving the security of the system.

[0145] In addition, the technical solution provided by the embodiment of the present application selects another suitable core network device to establish a PDU session according to the RSC carried in the session establishment request through the core network device, so as to establish a data transmission channel between the relay device and the DN. Since different core network devices with session management functions support different service attributes, the embodiment of the present application fully considers the factors affecting the PDU session establishment process, selects the core network device to establish the PDU session through the RSC corresponding to the service attribute, ensures that the selected core network device supports the attributes corresponding to the service requested by the remote device, and improves the success rate of the PDU session establishment.

[0146] From the introduction and description of the above embodiments, it can be seen that the first core network device can select the second core network device with the first RSC. The embodiments of the present application provide two methods for selecting the second core network device. One method is to select the second core network device corresponding to the first RSC, and the other method is to determine the session parameter information of the PDU session according to the first RSC, and then select the second core network device corresponding to the session parameter information.

[0147] First, the first method is introduced.

[0148] In one example, if Fig.10 As shown, the above step 820 includes:

[0149] Step 822: The first core network device selects a second core network device corresponding to the first RSC according to the first configuration information. The first configuration information includes a correspondence between the RSC and the second core network device.

[0150] The first configuration information includes the correspondence between the RSC and the second core network device. The embodiment of the present application does not limit the number of correspondences contained in the first configuration information. Optionally, the correspondence is one or more. The embodiment of the present application does not limit the correspondence between the RSC and the second core network device. Optionally, there is a one-to-one correspondence between the RSC and the second core network device; or, multiple RSCs correspond to one second core network device; or, one RSC corresponds to multiple second core network devices, which is not limited by the embodiment of the present application. Optionally, the first configuration information is pre-configured in the first core network device, that is, the first configuration information is the local configuration information of the first core network device; or, the first configuration information is predefined in the communication protocol, which is not limited by the embodiment of the present application.

[0151] Based on this, Fig.10 As shown, the above step 830 includes: step 832, the first core network device sends a second session establishment request to the second core network device, and the second session establishment request includes the first RSC.

[0152] The first core network device includes the first RSC in the session establishment request sent to the second core network device, so that the second core network device determines the session parameter information used in the process of establishing the PDU session according to the first RSC. The embodiment of the present application does not limit the manner in which the second core network device determines the session parameter information of the PDU session. Several manners in which the second core network device determines the session parameter information are provided below.

[0153] Alternatively, if Fig.10 As shown, the above step 840 includes: step 842, the second core network device determines the session parameter information corresponding to the first RSC according to the third configuration information, and the third configuration information includes the correspondence between the RSC and the session parameter information; step 844, the second core network device establishes a PDU session according to the session parameter information.

[0154] The third configuration information includes the correspondence between the RSC and the session parameter information. The embodiment of the present application does not limit the number of correspondences contained in the third configuration information. Optionally, the correspondence is one or more. The embodiment of the present application does not limit the correspondence between the RSC and the session parameter information. Optionally, there is a one-to-one correspondence between the RSC and the session parameter information; or, multiple RSCs correspond to one session parameter information; or, one RSC corresponds to multiple session parameter information. The embodiment of the present application does not limit this. Optionally, the third configuration information is pre-configured in the second core network device, that is, the third configuration information is the local configuration information of the second core network device; or, the third configuration information is predefined in the communication protocol; or, the third configuration information is configured to the second core network device by other core network devices, such as by the first core network device to the second core network device. The embodiment of the present application does not limit this.

[0155] The second core network device can determine the session parameter information corresponding to the first RSC based on the third configuration information, and then establish a PDU session based on the session parameter information. The session parameter information is the session parameter information corresponding to the PDU session to be established by the second core network device, that is, the session parameter information corresponding to the PDU session requested to be established by the relay device. Optionally, the session parameter information includes at least one of the following: slice information, DNN information, SSC mode information, and session type information. The embodiment of the present application does not limit the specific content of the session parameter information.

[0156] Alternatively, if Fig.10 As shown, the above step 840 includes: step 846, the second core network device determines the session parameter information according to the first information field in the first RSC; step 848, the second core network device establishes a PDU session according to the session parameter information.

[0157] The session parameter information corresponding to the PDU session can also be indicated by the information field of the first RSC. In an embodiment of the present application, the first information field of the first RSC is used to indicate the session parameter information. The second core network device can determine the session parameter information based on the first information field to establish the PDU session using the session parameter information. The embodiment of the present application does not limit the number of bits of the first information field. Optionally, the first information field is 1 bit or multiple bits. In actual applications, the number of bits of the first information field can be determined in combination with the length of the session parameter information, the length of the first RSC, etc. The embodiment of the present application also does not limit the number of first information fields. Optionally, the first information field includes one or more information fields in the first RSC.

[0158] In another example, if Fig.10 As shown, the above step 820 includes:

[0159] Step 824: The first core network device sends a first RSC to the third core network device.

[0160] The second core network device can also be selected by the third core network device. In the embodiment of the present application, the first core network device can send the first RSC to the third core network device, and the third core network device selects the second core network device corresponding to the first RSC. For the introduction of the third core network device selecting the second core network device according to the first RSC, please refer to the above method embodiment, which will not be repeated here. Optionally, the above third core network device includes at least one of the following devices: NRF entity (or "NRF"), PCF entity (or "PCF").

[0161] Step 826: The third core network device sends device information to the first core network device, where the device information is used to indicate the second core network device corresponding to the first RSC.

[0162] In order to indicate the selected second core network device to the first core network device, the third core network device needs to send device information to the first core network device, and the device information is used to indicate the second core network device selected by the third core network device and corresponding to the first RSC. The embodiment of the present application does not limit the specific content of the device information. Optionally, the device information includes at least one of the following: address information of the second core network device, identification information of the second core network device, wherein the address information of the second core network device is used to indicate the address of the second core network device (such as a network address, a physical address, etc.); the identification information of the second core network device is used to indicate the identification of the second core network device (such as a unique device identifier, a device ID, etc.).

[0163] Alternatively, if Fig.10As shown, the above step 830 includes: step 832, the first core network device sends a second session establishment request to the second core network device, the second session establishment request is used to request to establish a PDU session, and the second session establishment request includes the first RSC. For the introduction of step 832, please refer to the above embodiment, which will not be repeated here.

[0164] Alternatively, if Fig.10 As shown, the above step 840 includes: step 842, the second core network device determines the session parameter information corresponding to the first RSC according to the third configuration information, and the third configuration information includes the corresponding relationship between the RSC and the session parameter information; step 844, the second core network device establishes a PDU session according to the session parameter information. Optionally, as Fig.10 As shown, the above step 840 includes: step 846, the second core network device determines the session parameter information according to the first information field in the first RSC; step 848, the second core network device establishes the PDU session according to the session parameter information. For the introduction of steps 842, 844, 846, and 848, please refer to the above embodiment, which will not be repeated here.

[0165] It should be noted that in the embodiment of the present application, the steps of the above method can be arbitrarily combined without violating logic. For example, after the above step 822, the above step 832 is executed, and then the above step 842 and step 844 are executed; for another example, after the above step 822, the above step 832 is executed, and then the above step 846 and step 848 are executed; for another example, after the above step 824 and step 826, the above step 832 is executed, and then the above step 842 and step 844 are executed; for another example, after the above step 824 and step 826, the above step 832 is executed, and then the above step 846 and step 848 are executed. It should be understood that these should all fall within the scope of protection of the present application.

[0166] Next, the second method is introduced.

[0167] In another example, Fig.11 As shown, the above step 820 includes:

[0168] Step 821: The first core network device sends a first RSC to the third core network device.

[0169] In an embodiment of the present application, the first core network device may send a first RSC to a third core network device, and the third core network device determines the session parameter information required to establish a PDU session according to the first RSC. Optionally, the third core network device includes at least one of the following devices: an NRF entity (or referred to as "NRF"), a PCF entity (or referred to as "PCF").

[0170] Step 823: The third core network device sends session parameter information corresponding to the first RSC to the first core network device.

[0171] After the third core network device receives the first RSC, it can determine the session parameter information according to the second configuration information. For an introduction to the third core network device determining the session parameter information and the second configuration information according to the first RSC, please refer to the following embodiment of the first core network device determining the session parameter information, which will not be elaborated here. Optionally, the session parameter information includes at least one of the following: slice information, DNN information, SSC mode information, and session type information. The embodiment of the present application does not limit the specific content of the session parameter information.

[0172] After the third core network device determines the session parameter information, the session parameter information may be sent to the first core network device, so that the first core network device selects the second core network device according to the session parameter information.

[0173] Step 825: The first core network device selects a second core network device corresponding to the session parameter information according to the third configuration information, where the third configuration information includes a correspondence between the session parameter information and the second core network device.

[0174] The third configuration information includes the correspondence between the RSC and the session parameter information. Optionally, the third configuration information is pre-configured in the first core network device, that is, the third configuration information is the local configuration information of the first core network device; or, the third configuration information is predefined in the communication protocol, which is not limited in the embodiment of the present application. For other descriptions of the third configuration information, please refer to the above method embodiment, which will not be elaborated here.

[0175] Based on this, Fig.11 As shown, the above step 830 includes: step 831, the first core network device sends a second session establishment request to the second core network device, and the second session establishment request includes session parameter information.

[0176] Since the first core network device has determined the session parameter information, the second session establishment request sent by the first core network device to the second core network device may include the session parameter information, so that the second core network device can directly establish a PDU session based on the session parameter information.

[0177] Based on this, Fig.11 As shown, the above step 840 includes: Step 841, the second core network device establishes a PDU session according to the session parameter information.

[0178] After receiving the second session establishment request, the second core network device parses the second session establishment request to obtain session parameter information, and then the second core network device establishes a PDU session according to the parsed session parameter information to establish a data transmission channel between the relay device and the DN.

[0179] In another example, Fig.11 As shown, the above step 820 includes:

[0180] Step 827: The first core network device determines the session parameter information corresponding to the first RSC according to the second configuration information, where the second configuration information includes a correspondence between the RSC and the session parameter information.

[0181] The second configuration information includes a correspondence between the RSC and the session parameter information. The embodiment of the present application does not limit the number of correspondences contained in the second configuration information. Optionally, the correspondence is one or more. The embodiment of the present application does not limit the correspondence between the RSC and the session parameter information. Optionally, there is a one-to-one correspondence between the RSC and the session parameter information; or, multiple RSCs correspond to one session parameter information; or, one RSC corresponds to multiple session parameter information, and the embodiment of the present application does not limit this. Optionally, the second configuration information is pre-configured in the first core network device, that is, the first configuration information is the local configuration information of the first core network device; or, the first configuration information is predefined in the communication protocol, and the embodiment of the present application does not limit this. The first core network device can determine the session parameter information corresponding to the first RSC according to the second configuration information, so as to further determine the second core network device according to the session parameter information. Optionally, the session parameter information includes at least one of the following: slice information, DNN information, SSC mode information, and session type information. The embodiment of the present application does not limit the specific content of the session parameter information.

[0182] Step 829: The first core network device selects a second core network device corresponding to the session parameter information according to the third configuration information, where the third configuration information includes a correspondence between the session parameter information and the second core network device.

[0183] For the description of step 829, please refer to the above step 825, which will not be repeated here.

[0184] Based on this, Fig.11 As shown, the above step 830 includes: step 831, the first core network device sends a second session establishment request to the second core network device, and the second session establishment request includes session parameter information. Based on this, Fig.11As shown, the above step 840 includes: Step 841, the second core network device establishes a PDU session according to the session parameter information. For the introduction of steps 831 and 841, please refer to the above embodiment, which will not be repeated here.

[0185] In another example, Fig.11 As shown, the above step 820 includes:

[0186] Step 82A: The first core network device determines session parameter information according to the first information field in the first RSC, where the session parameter information is used to establish a PDU session.

[0187] For an introduction to the first information field, please refer to the introduction to the above steps 846 and 848, which will not be repeated here. The first core network device can determine the session parameter information for establishing a PDU session based on the first information field in the first RSC, so as to select the second core network device based on the session parameter information. Optionally, the above session parameter information includes at least one of the following: slice information, DNN information, SSC mode information, and session type information.

[0188] Step 82B: The first core network device selects a second core network device corresponding to the session parameter information according to the third configuration information, where the third configuration information includes a correspondence between the session parameter information and the second core network device.

[0189] For an introduction to step 82B, please refer to the above step 825, which will not be elaborated here.

[0190] Based on this, Fig.11 As shown, the above step 830 includes: step 831, the first core network device sends a second session establishment request to the second core network device, and the second session establishment request includes session parameter information. Based on this, Fig.11 As shown, the above step 840 includes: Step 841, the second core network device establishes a PDU session according to the session parameter information. For the introduction of steps 831 and 841, please refer to the above embodiment, which will not be repeated here.

[0191] It should be noted that in the embodiment of the present application, the steps of the above method can be arbitrarily combined without violating logic. For example, after the above steps 821, 823 and 825, the above step 831 is executed, and then the above step 841 is executed; for another example, after the above steps 827 and 829, the above step 831 is executed, and then the above step 841 is executed; for another example, after the above steps 82A and 82B, the above step 831 is executed, and then the above step 841 is executed. It should be understood that these should all fall within the scope of protection of the present application.

[0192] Another point that needs to be explained is that the first configuration information in the embodiment of the present application is only used to represent the configuration information containing the correspondence between the first RSC and the second core network device, the second configuration information is only used to represent the configuration information containing the correspondence between the first RSC and the session parameter information, and the third configuration information is only used to represent the configuration information containing the correspondence between the session parameter information and the second core network device. It should be understood that the first configuration information, the second configuration information, and the third configuration information are not used to limit the configuration information of a certain core network device.

[0193] In summary, the technical solution provided by the embodiment of the present application realizes a specific method of selecting a core network device based on RSC by selecting a core network device corresponding to the RSC carried in the session establishment request according to the correspondence between the RSC and the core network device. In addition, the embodiment of the present application provides a variety of selection subjects and a variety of selection methods, which can be combined in a variety of forms to improve the flexibility of core network device selection.

[0194] One point that needs to be explained is that in the above method embodiment, the session establishment method provided by the present application is mainly introduced and explained from the perspective of the interaction between the relay device, the first core network device and the second core network device. The above steps performed by the relay device can be independently implemented as a session establishment method on the relay device side; the above steps performed by the first core network device can be independently implemented as a session establishment method on the first core network device side; the above steps performed by the second core network device can be independently implemented as a session establishment method on the second core network device side.

[0195] The following is an embodiment of the device of the present application, which can be used to execute the embodiment of the method of the present application. For details not disclosed in the embodiment of the device of the present application, please refer to the embodiment of the method of the present application.

[0196] Please refer to Fig.12 , which shows a block diagram of a session establishment device provided by an embodiment of the present application. The device has the function of implementing the above-mentioned relay device side method example, and the function can be implemented by hardware, or by hardware executing corresponding software. The device can be the relay device described above, or it can be set in the relay device. Fig.12 As shown, the device 1200 may include: a first request sending module 1210.

[0197] The first request sending module 1210 is used to send a first session establishment request to the first core network device, where the first session establishment request is used to request to establish a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0198] In one example, the first RSC is used to select a second core network device, and the second core network device is used to establish the PDU session.

[0199] In one example, if Fig.13 As shown, the apparatus 1200 further includes: a first response receiving module 1220, configured to receive a first session establishment response from the first core network device, wherein the first session establishment response is used to indicate that the PDU session establishment is completed.

[0200] In one example, the first session establishment response includes the first RSC.

[0201] To sum up, the technical solution provided by the embodiment of the present application sends a session establishment request to the core network device through a relay device. The session establishment request carries an RSC corresponding to the service attributes. Since the RSC is a service code, it is not easy to crack and leak. Compared with directly carrying service attributes in the session establishment request, which may cause the leakage of service attributes and affect the system security, the embodiment of the present application ensures that the core network clearly defines the service attributes while also ensuring the privacy protection of the service attributes, thereby improving the security of the system.

[0202] Please refer to Fig.13 , which shows a block diagram of a session establishment device provided by an embodiment of the present application. The device has the function of implementing the above-mentioned first core network device side method example, and the function can be implemented by hardware, or by hardware executing corresponding software. The device can be the first core network device described above, and can also be set in the first core network device. Fig.14 As shown, the device 1400 may include: a first request receiving module 1410.

[0203] The first request receiving module 1410 is used to receive a first session establishment request from a relay device, where the first session establishment request is used to request to establish a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0204] In one example, if Fig.15 As shown, the apparatus 1400 further includes: a device selection module 1420, configured to select a second core network device according to the first RSC, wherein the second core network device is configured to establish the PDU session.

[0205] In one example, if Fig.15 As shown, the device selection module 1420 is used to: select a second core network device corresponding to the first RSC according to first configuration information, and the first configuration information includes a corresponding relationship between the RSC and the second core network device.

[0206] In one example, if Fig.15 As shown, the device selection module 1420 is used to: send the first RSC to the third core network device; receive device information from the third core network device, and the device information is used to indicate the second core network device corresponding to the first RSC.

[0207] In one example, the device information includes at least one of the following: address information of the second core network device, and identification information of the second core network device.

[0208] In one example, if Fig.15 As shown, the device selection module 1420 is used to: send the first RSC to a third core network device; receive session parameter information corresponding to the first RSC from the third core network device, the session parameter information is used to establish the PDU session; and select a second core network device corresponding to the session parameter information according to third configuration information, the third configuration information including the correspondence between the session parameter information and the second core network device.

[0209] In one example, if Fig.15 As shown, the device selection module 1420 is used to: determine the session parameter information corresponding to the first RSC based on the second configuration information, the session parameter information is used to establish the PDU session, and the second configuration information includes the correspondence between the RSC and the session parameter information; select the second core network device corresponding to the session parameter information based on the third configuration information, and the third configuration information includes the correspondence between the session parameter information and the second core network device.

[0210] In one example, if Fig.15 As shown, the device selection module 1420 is used to: determine session parameter information based on the first information field in the first RSC, and the session parameter information is used to establish the PDU session; select a second core network device corresponding to the session parameter information based on third configuration information, and the third configuration information includes the correspondence between the session parameter information and the second core network device.

[0211] In one example, the session parameter information includes at least one of the following: slice information, DNN information, SSC mode information, and session type information.

[0212] In one example, the third core network device includes at least one of the following devices: an NRF entity, a PCF entity.

[0213] In one example, if Fig.15As shown, the apparatus 1400 further includes: a second request sending module 1430, configured to send a second session establishment request to the second core network device, wherein the second session establishment request is used to request establishment of the PDU session, and the second session establishment request includes the first RSC.

[0214] In one example, if Fig.15 As shown, the apparatus 1400 further includes: a second request sending module 1430, used to send a second session establishment request to the second core network device, wherein the second session establishment request is used to request establishment of the PDU session, and the second session establishment request includes the session parameter information.

[0215] In one example, if Fig.15 As shown, the apparatus 1400 further includes: a first response sending module 1440, configured to send a first session establishment response to the relay device, wherein the first session establishment response is used to indicate that the PDU session establishment is completed.

[0216] In one example, the first session establishment response includes the first RSC.

[0217] To sum up, the technical solution provided by the embodiment of the present application sends a session establishment request to the core network device through a relay device. The session establishment request carries an RSC corresponding to the service attributes. Since the RSC is a service code, it is not easy to crack and leak. Compared with directly carrying service attributes in the session establishment request, which may cause the leakage of service attributes and affect the system security, the embodiment of the present application ensures that the core network clearly defines the service attributes while also ensuring the privacy protection of the service attributes, thereby improving the security of the system.

[0218] Please refer to Fig.16 , which shows a block diagram of a session establishment device provided by an embodiment of the present application. The device has the function of implementing the above-mentioned second core network device side method example, and the function can be implemented by hardware, or by hardware executing corresponding software. The device can be the second core network device described above, or it can be set in the second core network device. Fig.16 As shown, the device 1600 may include: a second request receiving module 1610 and a session establishing module 1620.

[0219] The second request receiving module 1610 is used to receive a second session establishment request from a first core network device, where the second core network device is selected by the first core network device based on the first RSC.

[0220] The session establishing module 1620 is used to establish a PDU session between the relay device and the DN according to the second session establishment request.

[0221] In one example, the second session establishment request includes the first RSC; the session establishment module 1620 is used to: determine the session parameter information corresponding to the first RSC based on third configuration information, the third configuration information including the correspondence between the RSC and the session parameter information; and establish the PDU session based on the session parameter information.

[0222] In one example, the second session establishment request includes the first RSC; the session establishment module 1620 is used to: determine session parameter information according to the first information field in the first RSC; and establish the PDU session according to the session parameter information.

[0223] In one example, the second session establishment request includes session parameter information corresponding to the first RSC; the session establishment module 1620 is used to establish the PDU session according to the session parameter information.

[0224] In one example, the session parameter information includes at least one of the following: slice information, DNN information, SSC mode information, and session type information.

[0225] To sum up, the technical solution provided by the embodiment of the present application sends a session establishment request to the core network device through a relay device. The session establishment request carries an RSC corresponding to the service attributes. Since the RSC is a service code, it is not easy to crack and leak. Compared with directly carrying service attributes in the session establishment request, which may cause the leakage of service attributes and affect the system security, the embodiment of the present application ensures that the core network clearly defines the service attributes while also ensuring the privacy protection of the service attributes, thereby improving the security of the system.

[0226] One point that needs to be explained is that the device provided in the above embodiment only uses the division of the above-mentioned functional modules as an example to implement its functions. In actual applications, the above-mentioned functions can be assigned to different functional modules according to actual needs, that is, the content structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0227] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0228] Please refer to Fig.17, which shows a schematic diagram of the structure of a relay device 170 provided in an embodiment of the present application. For example, the relay device can be used to execute the above-mentioned relay device side session establishment method. Specifically, the relay device 170 may include: a processor 171, and a transceiver 172 connected to the processor 171; wherein:

[0229] The processor 171 includes one or more processing cores. The processor 171 executes various functional applications and information processing by running software programs and modules.

[0230] The transceiver 172 includes a receiver and a transmitter. Optionally, the transceiver 172 is a communication chip.

[0231] In one example, the relay device 170 further includes: a memory and a bus. The memory is connected to the processor via the bus. The memory can be used to store a computer program, and the processor is used to execute the computer program to implement the various steps performed by the relay device in the above method embodiment.

[0232] In addition, the memory may be implemented by any type of volatile or non-volatile storage device or a combination thereof, including but not limited to: RAM (Random-Access Memory) and ROM (Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory or other solid-state storage technology, CD-ROM (Compact Disc Read-Only Memory), DVD (Digital Video Disc) or other optical storage, tape cassettes, magnetic tapes, disk storage or other magnetic storage devices. Among them:

[0233] The transceiver 172 is used to send a first session establishment request to the first core network device, where the first session establishment request is used to request to establish a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0234] In one example, the first RSC is used to select a second core network device, and the second core network device is used to establish the PDU session.

[0235] In one example, the transceiver 172 is further used to receive a first session establishment response from the first core network device, where the first session establishment response is used to indicate that the PDU session establishment is complete.

[0236] In one example, the first session establishment response includes the first RSC.

[0237] Please refer to Fig.18 , which shows a schematic diagram of the structure of a core network device 180 provided by an embodiment of the present application. For example, the core network device can be used to execute the above-mentioned first core network device side session establishment method; or, used to execute the above-mentioned first core network device side session establishment method. Specifically, the core network device 180 may include: a processor 181, and a transceiver 182 connected to the processor 181; wherein:

[0238] The processor 181 includes one or more processing cores. The processor 181 executes various functional applications and information processing by running software programs and modules.

[0239] The transceiver 182 includes a receiver and a transmitter. Optionally, the transceiver 182 is a communication chip.

[0240] In one example, the core network device 180 further includes: a memory and a bus. The memory is connected to the processor via the bus. The memory can be used to store a computer program, and the processor is used to execute the computer program to implement the various steps performed by the first core network device or the second core network device in the above method embodiment.

[0241] In addition, the memory may be implemented by any type of volatile or non-volatile storage device or a combination thereof, including but not limited to: RAM (Random-Access Memory) and ROM (Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory or other solid-state storage technology, CD-ROM (Compact Disc Read-Only Memory), DVD (Digital Video Disc) or other optical storage, tape cassettes, magnetic tapes, disk storage or other magnetic storage devices. Among them:

[0242] For the case where the core network device 180 is used to execute the first core network device side session establishment method:

[0243] The transceiver 182 is used to receive a first session establishment request from a relay device, where the first session establishment request is used to request to establish a PDU session between the relay device and the DN, and the first session establishment request includes a first RSC.

[0244] In one example, the processor 181 is used to select a second core network device according to the first RSC, and the second core network device is used to establish the PDU session.

[0245] In one example, the processor 181 is used to select a second core network device corresponding to the first RSC according to first configuration information, and the first configuration information includes a correspondence between the RSC and the second core network device.

[0246] In one example, the transceiver 182 is used to send the first RSC to a third core network device; the transceiver 182 is used to receive device information from the third core network device, and the device information is used to indicate a second core network device corresponding to the first RSC.

[0247] In one example, the device information includes at least one of the following: address information of the second core network device, and identification information of the second core network device.

[0248] In one example, the transceiver 182 is used to send the first RSC to a third core network device; the transceiver 182 is used to receive session parameter information corresponding to the first RSC from the third core network device, and the session parameter information is used to establish the PDU session; the processor 181 is used to select a second core network device corresponding to the session parameter information according to third configuration information, and the third configuration information includes a correspondence between the session parameter information and the second core network device.

[0249] In one example, the processor 181 is used to: determine session parameter information corresponding to the first RSC based on second configuration information, the session parameter information is used to establish the PDU session, and the second configuration information includes a correspondence between the RSC and the session parameter information; and select a second core network device corresponding to the session parameter information based on third configuration information, and the third configuration information includes a correspondence between the session parameter information and the second core network device.

[0250] In one example, the processor 181 is used to: determine session parameter information based on the first information field in the first RSC, and the session parameter information is used to establish the PDU session; select a second core network device corresponding to the session parameter information based on third configuration information, and the third configuration information includes a correspondence between the session parameter information and the second core network device.

[0251] In one example, the session parameter information includes at least one of the following: slice information, DNN information, SSC mode information, and session type information.

[0252] In one example, the third core network device includes at least one of the following devices: an NRF entity, a PCF entity.

[0253] In one example, the transceiver 182 is used to send a second session establishment request to the second core network device, where the second session establishment request is used to request establishment of the PDU session, and the second session establishment request includes the first RSC.

[0254] In one example, the transceiver 182 is used to send a second session establishment request to the second core network device, where the second session establishment request is used to request establishment of the PDU session, and the second session establishment request includes the session parameter information.

[0255] In an example, the transceiver 182 is used to send a first session establishment response to the relay device, where the first session establishment response is used to indicate that the PDU session establishment is complete.

[0256] In one example, the first session establishment response includes the first RSC.

[0257] For the case where the core network device 180 is used to execute the second core network device side session establishment method:

[0258] The transceiver 182 is configured to receive a second session establishment request from a first core network device, where the second core network device is selected by the first core network device based on the first RSC;

[0259] The processor 181 is configured to establish a PDU session between the relay device and the DN according to the second session establishment request.

[0260] In one example, the second session establishment request includes the first RSC; the processor 181 is used to: determine the session parameter information corresponding to the first RSC based on third configuration information, the third configuration information including the correspondence between the RSC and the session parameter information; and establish the PDU session based on the session parameter information.

[0261] In one example, the second session establishment request includes the first RSC; the processor 181 is used to: determine session parameter information according to the first information field in the first RSC; and establish the PDU session according to the session parameter information.

[0262] In one example, the second session establishment request includes session parameter information corresponding to the first RSC; the processor 181 is used to: establish the PDU session according to the session parameter information.

[0263] In one example, the session parameter information includes at least one of the following: slice information, DNN information, SSC mode information, and session type information.

[0264] On the other hand, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. The computer program is used to be executed by a processor of a relay device to implement the above-mentioned relay device side session establishment method.

[0265] On the other hand, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. The computer program is used to be executed by a processor of a core network device to implement the session establishment method on the first core network device side as described above.

[0266] On the other hand, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. The computer program is used to be executed by a processor of a core network device to implement the above-mentioned second core network device side session establishment method.

[0267] On the other hand, an embodiment of the present application provides a chip, which includes a programmable logic circuit and / or program instructions. When the chip runs on a relay device, it is used to implement the above-mentioned relay device side session establishment method.

[0268] On the other hand, an embodiment of the present application provides a chip, which includes a programmable logic circuit and / or program instructions. When the chip runs on a core network device, it is used to implement the session establishment method on the first core network device side as mentioned above.

[0269] On the other hand, an embodiment of the present application provides a chip, which includes a programmable logic circuit and / or program instructions. When the chip runs on a core network device, it is used to implement the above-mentioned second core network device side session establishment method.

[0270] On the other hand, an embodiment of the present application provides a computer program product, which, when executed on a relay device, enables a computer to execute the above-mentioned method for establishing a session on the relay device side.

[0271] On the other hand, an embodiment of the present application provides a computer program product, which, when executed on a core network device, enables a computer to execute the above-mentioned first core network device side session establishment method.

[0272] On the other hand, an embodiment of the present application provides a computer program product, which, when executed on a core network device, enables a computer to execute the above-mentioned second core network device side session establishment method.

[0273] Those skilled in the art should be aware that in one or more of the above examples, the functions described in the embodiments of the present application can be implemented with hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein the communication media include any media that facilitates the transmission of a computer program from one place to another. The storage medium can be any available medium that a general or special-purpose computer can access.

[0274] The above description is only an exemplary embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A session establishment method, characterized in that: Applied in a relay device, the method comprises: Sending a first session establishment request to the first core network device, where the first session establishment request is used to request to establish a protocol data unit (PDU) session between the relay device and the data network DN, and the first session establishment request includes a first relay service code (RSC); The first RSC is used to select a second core network device, and the second core network device is used to establish the PDU session, wherein the data network DN is different from the second core network device.

2. The method according to claim 1, characterized in that: The method further comprises: A first session establishment response is received from the first core network device, where the first session establishment response is used to indicate that the PDU session establishment is complete.

3. The method according to claim 2, characterized in that The first session establishment response includes the first RSC.

4. A session establishment method, characterized in that: Applied in a first core network device, the method includes: receiving a first session establishment request from a relay device, wherein the first session establishment request is used to request establishment of a protocol data unit (PDU) session between the relay device and a data network DN, and the first session establishment request includes a first relay service code (RSC); and A second core network device is selected according to the first RSC, and the second core network device is used to establish the PDU session, wherein the data network DN is different from the second core network device.

5. The method according to claim 4, characterized in that The selecting a second core network device according to the first RSC includes: According to first configuration information, a second core network device corresponding to the first RSC is selected, and the first configuration information includes a corresponding relationship between the RSC and the second core network device.

6. The method according to claim 4, characterized in that The selecting a second core network device according to the first RSC includes: Sending the first RSC to a third core network device; Receive device information from the third core network device, where the device information is used to indicate the second core network device corresponding to the first RSC.

7. The method according to claim 6, characterized in that The device information includes at least one of the following: address information of the second core network device and identification information of the second core network device.

8. The method according to claim 4, characterized in that The selecting a second core network device according to the first RSC includes: Sending the first RSC to a third core network device; receiving session parameter information corresponding to the first RSC from the third core network device, where the session parameter information is used to establish the PDU session; According to the third configuration information, a second core network device corresponding to the session parameter information is selected, and the third configuration information includes a correspondence between the session parameter information and the second core network device.

9. The method according to claim 4, characterized in that The selecting a second core network device according to the first RSC includes: Determine, according to the second configuration information, session parameter information corresponding to the first RSC, the session parameter information being used to establish the PDU session, the second configuration information including a correspondence between the RSC and the session parameter information; According to the third configuration information, a second core network device corresponding to the session parameter information is selected, and the third configuration information includes a correspondence between the session parameter information and the second core network device.

10. The method according to claim 4, characterized in that The selecting a second core network device according to the first RSC includes: Determine session parameter information according to the first information field in the first RSC, where the session parameter information is used to establish the PDU session; According to the third configuration information, a second core network device corresponding to the session parameter information is selected, and the third configuration information includes a correspondence between the session parameter information and the second core network device.

11. The method according to any one of claims 5 to 10, characterized in that: The session parameter information includes at least one of the following: slice information, data network name DNN information, session and service continuity SSC mode information, and session type information.

12. The method according to any one of claims 6 to 8, characterized in that: The third core network device includes at least one of the following devices: a storage function NRF entity and a policy control function PCF entity of a network function entity.

13. The method according to any one of claims 5 to 7, characterized in that: The method further comprises: A second session establishment request is sent to the second core network device, where the second session establishment request is used to request establishment of the PDU session, and the second session establishment request includes the first RSC.

14. The method according to any one of claims 8 to 10, characterized in that The method further comprises: A second session establishment request is sent to the second core network device, where the second session establishment request is used to request establishment of the PDU session, and the second session establishment request includes the session parameter information.

15. The method according to any one of claims 4 to 10, characterized in that The method further comprises: A first session establishment response is sent to the relay device, where the first session establishment response is used to indicate that the PDU session establishment is complete.

16. The method according to claim 15, characterized in that The first session establishment response includes the first RSC.

17. A session establishment method, characterized in that: Applied in a second core network device, the method includes: receiving a second session establishment request from a first core network device, where the second core network device is selected by the first core network device based on a first relay service code RSC, wherein the first RSC is included in a first session establishment request received by the first core network device from a relay device, and the first session establishment request is used to request establishment of a protocol data unit (PDU) session between the relay device and a data network DN, wherein the data network DN is different from the second core network device; According to the second session establishment request, a protocol data unit PDU session is established between the relay device and the data network DN.

18. The method according to claim 17, characterized in that The second session establishment request includes the first RSC; The establishing a PDU session between the relay device and the DN according to the second session establishment request includes: Determine, according to third configuration information, session parameter information corresponding to the first RSC, wherein the third configuration information includes a correspondence between the RSC and the session parameter information; The PDU session is established according to the session parameter information.

19. The method according to claim 17, characterized in that The second session establishment request includes the first RSC; The establishing a PDU session between the relay device and the DN according to the second session establishment request includes: Determining session parameter information according to the first information field in the first RSC; The PDU session is established according to the session parameter information.

20. The method according to claim 17, characterized in that The second session establishment request includes session parameter information corresponding to the first RSC; The establishing a PDU session between the relay device and the DN according to the second session establishment request includes: The PDU session is established according to the session parameter information.

21. The method according to any one of claims 18 to 20, characterized in that The session parameter information includes at least one of the following: slice information, data network name DNN information, session and service continuity SSC mode information, and session type information.

22. A session establishment device, characterized in that: Set in a relay device, the device includes: A first request sending module is used to send a first session establishment request to a first core network device, wherein the first session establishment request is used to request to establish a protocol data unit PDU session between the relay device and the data network DN, and the first session establishment request includes a first relay business service code RSC; wherein the first RSC is used to select a second core network device, and the second core network device is used to establish the PDU session, wherein the data network DN is different from the second core network device.

23. The device according to claim 22, characterized in that The device also includes: The first response receiving module is used to receive a first session establishment response from the first core network device, where the first session establishment response is used to indicate that the PDU session establishment is completed.

24. The device according to claim 23, characterized in that The first session establishment response includes the first RSC.

25. A session establishing device, characterized in that: Set in a first core network device, the device includes: a first request receiving module, configured to receive a first session establishment request from a relay device, wherein the first session establishment request is used to request to establish a protocol data unit (PDU) session between the relay device and a data network DN, and the first session establishment request includes a first relay service code (RSC); and A device selection module is used to select a second core network device according to the first RSC, and the second core network device is used to establish the PDU session, wherein the data network DN is different from the second core network device.

26. The device according to claim 25, characterized in that The device selection module is used to: According to first configuration information, a second core network device corresponding to the first RSC is selected, and the first configuration information includes a corresponding relationship between the RSC and the second core network device.

27. The device according to claim 25, characterized in that The device selection module is used to: Sending the first RSC to a third core network device; Receive device information from the third core network device, where the device information is used to indicate the second core network device corresponding to the first RSC.

28. The device according to claim 27, characterized in that The device information includes at least one of the following: address information of the second core network device and identification information of the second core network device.

29. The device according to claim 25, characterized in that The device selection module is used to: Sending the first RSC to a third core network device; receiving session parameter information corresponding to the first RSC from the third core network device, where the session parameter information is used to establish the PDU session; According to the third configuration information, a second core network device corresponding to the session parameter information is selected, and the third configuration information includes a correspondence between the session parameter information and the second core network device.

30. The device according to claim 25, characterized in that The device selection module is used to: Determine, according to the second configuration information, session parameter information corresponding to the first RSC, the session parameter information being used to establish the PDU session, the second configuration information including a correspondence between the RSC and the session parameter information; According to the third configuration information, a second core network device corresponding to the session parameter information is selected, and the third configuration information includes a correspondence between the session parameter information and the second core network device.

31. The device according to claim 25, characterized in that The device selection module is used to: Determine session parameter information according to the first information field in the first RSC, where the session parameter information is used to establish the PDU session; According to the third configuration information, a second core network device corresponding to the session parameter information is selected, and the third configuration information includes a correspondence between the session parameter information and the second core network device.

32. The device according to any one of claims 29 to 31, characterized in that The session parameter information includes at least one of the following: slice information, data network name DNN information, session and service continuity SSC mode information, and session type information.

33. The device according to any one of claims 27 to 29, characterized in that The third core network device includes at least one of the following devices: a storage function NRF entity and a policy control function PCF entity of a network function entity.

34. The device according to any one of claims 26 to 28, characterized in that The device also includes: The second request sending module is used to send a second session establishment request to the second core network device, where the second session establishment request is used to request to establish the PDU session, and the second session establishment request includes the first RSC.

35. The device according to any one of claims 29 to 31, characterized in that The device also includes: The second request sending module is used to send a second session establishment request to the second core network device, where the second session establishment request is used to request to establish the PDU session, and the second session establishment request includes the session parameter information.

36. The device according to any one of claims 25 to 31, characterized in that The device also includes: The first response sending module is used to send a first session establishment response to the relay device, where the first session establishment response is used to indicate that the PDU session establishment is completed.

37. The device according to claim 36, characterized in that The first session establishment response includes the first RSC.

38. A session establishment device, characterized in that: Set in the second core network device, the device includes: a second request receiving module, configured to receive a second session establishment request from a first core network device, wherein the second core network device is selected by the first core network device based on a first relay service code RSC, wherein the first RSC is included in a first session establishment request received by the first core network device from a relay device, and the first session establishment request is used to request establishment of a protocol data unit PDU session between the relay device and a data network DN, wherein the data network DN is different from the second core network device; The session establishing module is used to establish a protocol data unit PDU session between the relay device and the data network DN according to the second session establishment request.

39. The device according to claim 38, characterized in that The second session establishment request includes the first RSC; the session establishment module is used to: Determine, according to third configuration information, session parameter information corresponding to the first RSC, wherein the third configuration information includes a correspondence between the RSC and the session parameter information; The PDU session is established according to the session parameter information.

40. The device according to claim 38, characterized in that The second session establishment request includes the first RSC; the session establishment module is used to: Determining session parameter information according to the first information field in the first RSC; The PDU session is established according to the session parameter information.

41. The device according to claim 38, characterized in that The second session establishment request includes session parameter information corresponding to the first RSC; the session establishment module is used to: The PDU session is established according to the session parameter information.

42. The device according to any one of claims 38 to 41, characterized in that The session parameter information includes at least one of the following: slice information, data network name DNN information, session and service continuity SSC mode information, and session type information.

43. A relay device, characterized in that: The relay device includes: a processor, a transceiver and a memory connected to the processor; wherein: the memory is used to store a computer program, and the processor is used to execute the computer program to cooperate with the transceiver to implement the session establishment method described in any one of claims 1-3.

44. A core network device, characterized in that: The core network device includes: a processor, a transceiver and a memory connected to the processor; wherein: the memory is used to store a computer program, and the processor is used to execute the computer program to cooperate with the transceiver to implement the session establishment method described in any one of claims 4-16.

45. A core network device, characterized in that: The core network device includes: a processor, a transceiver and a memory connected to the processor; wherein: the memory is used to store a computer program, and the processor is used to execute the computer program to cooperate with the transceiver to implement the session establishment method described in any one of claims 17-21.

46. ​​A computer-readable storage medium, characterized in that The storage medium stores a computer program, and the computer program is used to be executed by a processor of the relay device to implement the session establishment method according to any one of claims 1 to 3.

47. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and the computer program is used to be executed by a processor of a core network device to implement the session establishment method as described in any one of claims 4 to 16.

48. A computer-readable storage medium, characterized in that The storage medium stores a computer program, which is used to be executed by a processor of a core network device to implement the session establishment method as described in any one of claims 17 to 21.

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