Communication method and communication device

Abstract

Provided are a communication method and a communication device. The method comprises: a terminal device receives a first message, the first message being used for requesting establishment of a first connection between the terminal device and a first core network element; and on the basis of the maximum number of connections allowed to be established by the terminal device, the terminal device determines whether to establish the first connection or not.

Description

Communication methods and communication equipment Technical Field

[0001] This application relates to the field of communication technology, and more specifically, to a communication method and a communication device. Background Technology

[0002] Current location and sensing services transmit data via user plane connections. However, managing user plane connections is a pressing technical problem that needs to be solved. Summary of the Invention

[0003] This application provides a communication method and a communication device. The various aspects covered by this application are described below.

[0004] In a first aspect, a communication method is provided, comprising: a terminal device receiving a first message, the first message being used to request the establishment of a first connection between the terminal device and a first core network element; the terminal device determining whether to establish the first connection based on the maximum number of connections allowed to be established by the terminal device.

[0005] In a second aspect, a communication method is provided, comprising: a second core network element receiving a second message sent by a first core network element, the second message being used to request the establishment of a first connection between a terminal device and the first core network element; the second core network element determining whether the terminal device allows the establishment of the first connection based on the maximum number of connections allowed to be established by the terminal device.

[0006] Thirdly, a communication method is provided, comprising: a first core network element sending a second message to a second core network element, the second message being used to request the establishment of a first connection between the terminal device and the first core network element; if the number of connections established by the terminal device does not exceed the maximum number of connections allowed to be established by the terminal device, the first core network element establishing the first connection with the terminal device.

[0007] Fourthly, a communication device is provided, the communication device being a terminal device, the communication device comprising: a first receiving unit, configured to receive a first message, the first message being configured to request the establishment of a first connection between the terminal device and a first core network element; and a first determining unit, configured to determine whether to establish the first connection based on the maximum number of connections allowed to be established by the terminal device.

[0008] Fifthly, a communication device is provided, the communication device being a second core network element, the communication device comprising: a second receiving unit, configured to receive a second message sent by a first core network element, the second message being configured to request the establishment of a first connection between a terminal device and the first core network element; and a second determining unit, configured to determine whether the terminal device allows the establishment of the first connection based on the maximum number of connections allowed to be established by the terminal device.

[0009] In a sixth aspect, a communication device is provided, the communication device being a first core network element, the communication device comprising: a third sending unit, configured to send a second message to a second core network element, the second message being configured to request the establishment of a first connection between the terminal device and the first core network element; and an establishment unit, configured to establish the first connection with the terminal device if the number of connections established by the terminal device does not exceed the maximum number of connections allowed to be established by the terminal device.

[0010] A seventh aspect provides a communication device including a transceiver, a memory, and a processor, wherein the memory is used to store a program, the processor is used to invoke the program in the memory, and to control the transceiver to receive or transmit signals so that the communication device performs the method as described in the first aspect, the second aspect, or the third aspect.

[0011] Eighth aspect, an apparatus is provided, including a processor for calling a program from a memory to cause the apparatus to perform the method as described in the first, second, or third aspect.

[0012] A ninth aspect provides a chip including a processor for calling a program from memory, causing a device having the chip mounted to perform the method as described in the first, second, or third aspect.

[0013] A tenth aspect provides a computer-readable storage medium having a program stored thereon that causes a computer to perform the methods described in the first, second, or third aspects.

[0014] Eleventhly, a computer program product is provided, including a program that causes a computer to perform the methods described in the first, second, or third aspects.

[0015] In a twelfth aspect, a computer program is provided that causes a computer to perform the methods described in the first, second, or third aspects.

[0016] In this embodiment of the application, the terminal device can control the connection (such as user plane connection) between the terminal device and the core network element according to the maximum number of connections (such as user plane connection) that it is allowed to establish, thereby helping to manage the connection (such as limiting the number of connection establishments and rejecting connection establishment requests that exceed the limit). Attached Figure Description

[0017] Figure 1 is an example architecture diagram of a communication system applicable to the embodiments of this application.

[0018] Figure 2 is a system architecture example diagram of the communication system applicable to the embodiments of this application.

[0019] Figure 3 is a system architecture example diagram of the sensing system applicable to the embodiments of this application.

[0020] Figure 4 is a system architecture example diagram of the positioning system applicable to the embodiments of this application.

[0021] Figure 5 is a schematic flowchart of a user plane connection establishment method applicable to an embodiment of this application.

[0022] Figure 6 is a schematic flowchart of another user plane connection establishment applicable to the embodiments of this application.

[0023] Figure 7 is a schematic flowchart of user plane connection establishment based on relocation applicable to the embodiments of this application.

[0024] Figure 8 is a schematic flowchart of a communication method provided in one embodiment of this application.

[0025] Figure 9 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0026] Figure 10 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0027] Figure 11 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0028] Figure 12 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0029] Figure 13 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0030] Figure 14 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0031] Figure 15 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0032] Figure 16 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0033] Figure 17 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0034] Figure 18 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0035] Figure 19 is a schematic flowchart of another possible implementation of the method shown in Figure 8.

[0036] Figure 20 is a schematic diagram of the structure of a communication device provided in one embodiment of this application.

[0037] Figure 21 is a schematic diagram of the structure of a communication device provided in another embodiment of this application.

[0038] Figure 22 is a schematic diagram of the structure of a communication device provided in another embodiment of this application.

[0039] Figure 23 is a schematic diagram of the structure of a device applicable to the embodiments of this application. Detailed Implementation

[0040] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0041] Communication system

[0042] Figure 1 is an example architecture diagram of a communication system 100 to which embodiments of this application can be applied. The communication system 100 may include a network device 110 and a terminal device 120. The network device 110 may be a device that communicates with the terminal device 120. The network device 110 can provide network coverage for a specific geographical area and can communicate with the terminal device 120 located within that coverage area. The terminal device 120 can access a network (such as a wireless network) through the network device 110. Optionally, the communication system 100 may also include other network entities such as a network controller and a mobility management entity (MME), which are not limited in this embodiment.

[0043] Figure 1 exemplarily illustrates a network device and two terminal devices. In some embodiments of this application, the communication system 100 may also include multiple network devices and each network device may include other numbers of terminal devices within its coverage area. This application does not limit this aspect.

[0044] It should be understood that the embodiments of this application can be applied to various communication systems. For example, the embodiments of this application can be applied to Global System for Mobile Communication (GSM), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), General Packet Radio Service (GPRS), Long Term Evolution (LTE), Advanced Long Term Evolution (LTE-A), New Radio (NR), evolution systems of NR, LTE-based access to unlicensed spectrum (LTE-U), NR-based access to unlicensed spectrum (NR-U), Universal Mobile Telecommunications System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (WiFi), and 5th-generation (5G) communication systems. The embodiments of this application can also be applied to other communication systems, such as future communication systems. The future communication system could be, for example, a beyond 5G (B5G) communication system, a sixth-generation mobile communication system, or a satellite communication system.

[0045] Traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, communication systems can now support not only traditional cellular communication but also one or more other types of communication. For example, a communication system can support one or more of the following communication methods: device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), vehicle-to-vehicle (V2V) communication, and vehicle-to-everything (V2X) communication. The embodiments of this application can also be applied to communication systems that support the above-mentioned communication methods.

[0046] The communication system in this application embodiment can be applied to carrier aggregation (CA) scenarios, dual connectivity (DC) scenarios, and standalone (SA) network deployment scenarios.

[0047] The communication system in this application embodiment can be applied to unlicensed spectrum. This unlicensed spectrum can also be considered a shared spectrum. Alternatively, the communication system in this application embodiment can also be applied to licensed spectrum. This licensed spectrum can also be considered a dedicated spectrum.

[0048] The embodiments of this application can be applied to terrestrial networks (TN) systems as well as non-terrestrial networks (NTN) systems. As an example, the NTN system can include an NR-based NTN system and an Internet of Things (IoT)-based NTN system.

[0049] A communication system may include one or more terminal devices. The terminal devices mentioned in the embodiments of this application may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user device, etc.

[0050] In some embodiments, the terminal device may be a station (ST) in a WLAN. In some embodiments, the terminal device may also be a cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA) device, handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, in-vehicle device, wearable device, terminal device in a next-generation communication system (e.g., NR system), or terminal device in a future evolved public land mobile network (PLMN) network, etc.

[0051] In some embodiments, the terminal device may be a device that provides voice and / or data connectivity to the user. For example, the terminal device may be a handheld device, an in-vehicle device, etc., with wireless connectivity. As some specific examples, the terminal device may be a mobile phone, tablet, laptop, PDA, mobile internet device (MID), wearable device, virtual reality (VR) device, augmented reality (AR) device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc.

[0052] In some embodiments, the terminal device may be deployed on land. For example, the terminal device may be deployed indoors or outdoors. In some embodiments, the terminal device may be deployed on water, such as on a ship. In some embodiments, the terminal device may be deployed in the air, such as on an airplane, balloon, or satellite.

[0053] In addition to terminal devices, the communication system may also include one or more network devices. In this embodiment, the network device may be a device for communicating with the terminal device; this network device may also be referred to as an access network device or a radio access network (RAN) device. For example, the network device may be a base station. In this embodiment, the network device may refer to an access network node (or device) that connects the terminal device to the wireless network. Access network equipment can broadly encompass various names listed below, or be interchangeable with them, such as: NodeB, evolved NodeB (eNB), next-generation NodeB (gNB), relay station, access point (AP), transmitting and receiving point (TRP), transmitting point (TP), master station (MeNB), secondary station (SeNB), multi-mode radio (MSR) node, home base station, network controller, access node, radio node, transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. Base stations can be macro base stations, micro base stations, relay nodes, donor nodes, or similar entities, or combinations thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, a device that performs base station functions in D2D, V2X, and M2M communications, a network-side device in a 6G network, or a device that performs base station functions in future communication systems. A base station can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the network equipment.

[0054] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move depending on the location of the mobile base station. In other examples, a helicopter or drone can be configured as a device to communicate with another base station.

[0055] In some deployments, the network device in this application embodiment may refer to a CU or a DU, or the network device may include both a CU and a DU. The gNB may also include an AAU.

[0056] By way of example and not limitation, in the embodiments of this application, the network device may have mobility characteristics; for example, the network device may be a mobile device. In some embodiments of this application, the network device may be satellite-based or space-based, that is, the network device is installed on a satellite or flying equipment. In some embodiments of this application, the network device may also be a base station installed in locations such as land or water.

[0057] In this embodiment, the network device can provide services to a cell. The terminal device communicates with the network device through the transmission resources (e.g., frequency domain resources, or spectrum resources) used by the cell. The cell can be the cell corresponding to the network device (e.g., a base station). The cell can belong to a macro base station or to a base station corresponding to a small cell. The small cell can include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage area and low transmission power, and are suitable for providing high-speed data transmission services.

[0058] It should be understood that devices with communication functions in the network / system of this application embodiment can be referred to as communication devices. Taking the communication system 100 shown in FIG1 as an example, the communication devices may include network devices 110 and terminal devices 120 with communication functions. Network devices 110 and terminal devices 120 can be the specific devices described above, which will not be repeated here. The communication devices may also include other devices in the communication system 100, such as network controllers, mobility management entities, and other network entities, which are not limited in this application embodiment.

[0059] Network system architecture

[0060] Figure 2 illustrates an exemplary system architecture diagram of a communication system applicable to embodiments of this application, using a 5G system as an example. As shown in Figure 2, the system architecture of a 5G network may include: a terminal device (also known as a UE) 201, an access network device 202 (including a radio access network (RAN) or an access network (AN)), an access and mobility management function (AMF) network element 203, a session management function (SMF) network element 204, a user plane function (UPF) network element 205, a policy control function (PCF) network element 206, an application function (AF) network element 209, a data network (DN) 208, a network slice selection function (NSSF) 211, an authentication server function (AUSF) 210, and a unified data management (UDM) network element 207.

[0061] Terminal device 201 can be any of the terminal devices shown in Figure 1, which will not be described in detail here.

[0062] Access network equipment 202 is the access device through which terminal devices wirelessly access the network architecture. It is primarily responsible for air interface-side radio resource management, Quality of Service (QoS) management, data compression, and encryption. Examples include NodeBs, eNodeBs, base stations in 5G or NR mobile communication systems, and base stations in future mobile communication systems.

[0063] UPF element 205, AMF element 203, SMF element 204, and PCF element 206 are network functions (NFs) of the 3rd Generation Partnership Project (3GPP) core network, and can be referred to as core network elements. UPF element 205 can be called a user plane function element, mainly responsible for user data transmission. The other elements can be called control plane function elements, mainly responsible for authentication, authorization, registration management, session management, mobility management, and policy control, to ensure reliable and stable transmission of user data.

[0064] The UPF network element 205 (or simply "UPF") can be used to forward and receive data from terminals. For example, the UPF network element can receive service data from the data network and transmit it to the terminal through the access network equipment; the UPF network element can also receive user data from the terminal through the access network equipment and forward it to the data network. The transmission resources allocated and scheduled by the UPF network element for the terminal are managed and controlled by the SMF network element. The bearer between the terminal and the UPF network element can include: the user plane connection between the UPF network element and the access network equipment, and the establishment of a channel between the access network equipment and the terminal. The user plane connection is a Quality of Service (QoS) flow that can be established between the UPF network element and the access network equipment for transmitting data.

[0065] The AMF network element 203 (or "AMF" for short) can be used to manage terminal access to the core network, such as terminal location updates, network registration, access control, terminal mobility management, and terminal attachment and detachment. The AMF network element can also provide control plane storage resources for a terminal's session, storing the session identifier and the associated SMF network element identifier, etc.

[0066] SMF network element 204 (or "SMF" for short) can be used to select user plane network elements for terminals, redirect user plane network elements for terminals, assign Internet Protocol (IP) addresses to terminals, establish bearers (also known as sessions) between terminals and UPF network elements, modify and release sessions, and control QoS.

[0067] PCF network element 206 (or simply "PCF") is used to provide policies, such as QoS policies and slice selection policies, to AMF network element 203 and SMF network element 204. PCF is responsible for formulating policies related to mobility management, session management, and billing of terminal devices.

[0068] AF element 209 (or simply "AF") is used to interact with 3GPP core network elements to support the routing of application-affected data, access network exposure functions, and interact with PCF elements for policy control, etc.

[0069] UDM Network Element 207 (or simply "UDM") includes functions such as generating and storing user subscription data and managing authentication data, and supports interaction with external third-party servers.

[0070] The DN 208 can provide data services to users for networks such as IP Multimedia Service (IMS) and the Internet. The DN 208 can contain various application servers (AS) that provide different application services, such as carrier services, Internet access, or third-party services. The application servers can implement the functions of AF (Active Network Element) network elements.

[0071] NSSF 211 is used for network slice selection and supports the following functions: selecting the set of network slice instances to serve the UE; determining allowed network slice selection assistance information (NSSAI), and, when necessary, determining the mapping to the subscribed single-network slice selection assistance information (S-NSSAI); determining the configured NSSAI, and, when necessary, determining the mapping to the subscribed S-NSSAI; determining the set of AMFs that may be used to query the UE, or determining a list of candidate AMFs based on configuration.

[0072] AUSF 210 is used to receive the AMF 203's request to authenticate the terminal. It requests a key from UDM 207 and then forwards the issued key to AMF 203 for authentication processing.

[0073] As shown in Figure 2, the terminal device connects to the AN (Access Layer) via the Uu interface to exchange access layer messages and wireless data. The terminal device also connects to the AMF (Anti-Access Stratification) network element via the N1 interface to exchange NAS messages. In addition to mobility management of the terminal device, the AMF network element is responsible for forwarding session management-related messages between the terminal device and the SMF network element. The UPF (Universal Power Grid) network element transmits data with the external data network via the N6 interface and with the AN via the N3 interface.

[0074] Current cellular networks, including 5G networks, are used solely for communication. However, the radio electromagnetic signals used by cellular networks can be used for more than just wireless data transmission and communication; they also possess environmental awareness capabilities. These capabilities include user motion or gesture recognition, respiratory monitoring, terminal movement speed measurement, environmental imaging, and weather monitoring. Therefore, future cellular networks could be considered not only for communication and data transmission but also for acquiring sensory information.

[0075] To support sensing capabilities in B5G networks, sensing functions (SFs) and corresponding procedures can be added to the 3GPP network. Communication devices can send and receive sensing information based on sensing tasks. A sensing task requires identifying the corresponding sensing target. When the sensing target is a terminal device, the corresponding terminal device can be found directly through its identity (ID) or IP address information, and this terminal device can be used as the sender or receiver of the sensing signal. This allows for the selection of other surrounding sensing nodes to complete the sensing task.

[0076] For integrated sensing, the main wireless sensing scenarios include the following:

[0077] Scenario 1 is a base station echo sensing link (single gNB sensing), where the base station can send sensing signals and receive echo signals;

[0078] Scenario 2 is an inter-base station sensing link (gNB-gNB sensing), where base station B can receive sensing signals sent by base station A;

[0079] Scenario 3 is an air interface uplink sensing link (UE-gNB uplink sensing), where the base station can receive sensing signals sent by the terminal device;

[0080] Scenario 4 is an air interface downlink sensing link (UE-gNB downlink sensing), where the terminal device can receive sensing signals sent by the base station;

[0081] Scenario 5 is a terminal echo sensing link (single UE sensing), where the terminal device can send sensing signals and receive echo signals;

[0082] Scenario 6 is a terminal-to-terminal sensing link (UE-UE sensing), where terminal device B can receive sensing signals sent by terminal device A.

[0083] In the initial stage of B5G communication and sensing integration, the focus is on reusing existing air interface signals to perform sensing actions, without introducing excessive air interface enhancements. In certain scenarios, considering the complexity of full-duplex implementation, collaborative sensing between terminal devices and / or network devices is the preferred approach. For sensing methods in scenarios 3 to 6, it may be necessary for terminal devices to report a large amount of sensing data to the sensing elements of the core network or obtain auxiliary data from the core network elements.

[0084] Figure 3 is an example diagram of a reference architecture for a sensing system. This reference architecture illustrates a possible process for controlling access network devices or terminal devices to perform terminal device-level sensing operations. The dashed lines in Figure 3 indicate that the network element or function is optional.

[0085] The sensing system reference architecture in Figure 3 includes: terminal device 301 (UE B), terminal device 302 (UE A), access network device 303, AMF network element 304, UDM network element 305, UPF network element 306, the control plane part (SF-control plane, SF-C) 307 (also called sensing control network element 307) of the sensing network element, the user plane part (SF-user plane, SF-U) of the sensing network element 308, the network data analytics function (NWDAF) network element 309, the location management function (LMF) network element 310, the PCF network element 311, the network exposure function (NEF) network element 312, and the AF network element 313.

[0086] The SF-C network element 307 (or simply "SF-C") can interact with the control plane network elements of the core network, is responsible for control plane message transmission, and provides the address of the user plane sensing function to the access network equipment or terminal equipment. As shown in Figure 3, the SF-C 307 can connect to AMF 304, UDM 305, NWDAF 309, LMF 310, PCF311, and NEF 312 through different sensing interfaces.

[0087] The SF-U network element 308 (or simply "SF-U") is responsible for collecting and analyzing sensing measurement data or related information generated by terminal devices or access network devices to obtain the final sensing results, and then making them available to terminal devices or applications. As shown in Figure 3, the sensing measurement data can be forwarded via UPF 306 or directly transmitted to the sensing user plane function.

[0088] NWDAF element 309 (or simply "NWDAF") can collect data from various core network elements, applications, operation and maintenance systems, and operation support systems, and then analyze this data to provide suggestions and solutions regarding network performance and health status.

[0089] The LMF network element 310 (or "LMF" for short) can interact with the core network to support the positioning function of terminal equipment.

[0090] The NEF element 312 (or simply "NEF") can be used to open up the capabilities of various NFs and transform internal and external information.

[0091] As shown in Figure 3, when an application sends a sensing request for a target terminal device to the 3GPP core network, the core network can select the correct access network device or auxiliary terminal device through the SF-C network element or AMF, triggering the ability to perform sensing-related radio measurements, initiating the measurement of sensing information, and generating sensing results. Considering the large amount of data exchanged between the terminal device and the sensing network element, the terminal device can complete the necessary interaction for sensing services with the sensing network element through user plane data transmission. The terminal device can send sensing data to the SF-U network element through the UPF network element by establishing a special protocol data unit (PDU) session.

[0092] Figure 4 is an example diagram of a reference architecture for a positioning system. The positioning system reference architecture in Figure 4 includes: terminal device 401, access network device 402, positioning reference unit (PRU) 403, AMF network element 404, LMF network element 405, NEF network element 406, UDM network element 407, location retrieval function (LRF) 408, gateway mobile location center (GMLC) 409, NWDAF network element 410, AF network element 411, and location services (LCS) client 412.

[0093] As shown in Figure 4, multiple core network elements or nodes participating in the positioning of terminal device 401 can be connected through relevant interfaces. PRU 403, LRF 408, GMLC 409, and LCS client 412 can all participate in the positioning / location management of terminal device 401.

[0094] It should be noted that the network elements in Figures 2 to 4 can be network components in hardware devices, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (e.g., a cloud platform). The network architectures shown in Figures 2 to 4 do not constitute a limitation on the corresponding network architectures. In specific implementations, the corresponding network architectures may include more or fewer network elements than shown in the figures, or combine certain network elements, etc. In addition, AN or RAN is represented by (R)AN in Figures 2 to 4. The user plane portion of the sensing network element in Figure 3 may also have other names, or may be shared with LMF, which is not limited here.

[0095] Referring to the positioning system architecture shown in Figure 4, it can be seen that positioning services also involve user plane (UP) transmission requirements. In some cases of positioning services, user plane data transmission is required between the terminal device and the core network. The configuration and data transmission process of the user plane in positioning services are illustrated below with reference to Figures 5 and 6.

[0096] Figure 5 is a schematic diagram of an LMF-triggered user plane connection establishment process. The dashed lines in Figure 5 indicate that this process is optional.

[0097] Referring to Figure 5, in step S501, the LMF can determine whether to utilize the user plane for positioning. As an example, the LMF can decide whether to use the user plane connection between the terminal device and the LMF for positioning based on the user plane positioning capability of the terminal device, the control plane congestion status (such as the AMF load status), and other implementation factors.

[0098] Optionally, the LMF can invoke the Nnrf_NFDiscovery service operation to retrieve control plane congestion status (such as AMF load information). Alternatively, the LMF can invoke the Nnrf_NFManagement_NFStatusSubscribe service to subscribe to specific AMF load information.

[0099] Optionally, if the AMF load information indicates control plane congestion and an available user plane connection exists between the terminal device and the LMF, the LMF may decide to use user plane positioning.

[0100] Optionally, if the user plane connection context of the target terminal device already exists in the LMF, and the LMF decides to use the user plane connection for positioning, then subsequent steps S502-S508 can be skipped.

[0101] Optionally, LMF can select user plane localization for specific localization methods (such as motion sensor-based methods). Which specific localization methods require user plane transmission depends on the implementation and local configuration.

[0102] Optionally, this procedure can also be triggered when the LMF receives a location request from the AMF via control plane signaling (as defined in Clauses 6.1 and 6.3 of specification TS23.273).

[0103] In step S502, the LMF sends user plane information. This user plane information may include the LMF's user plane location address. If the LMF decides to use the user plane for location, and no secure user plane connection has been established between the terminal device and the LMF, the LMF invokes the Namf_Communication_N1N2MessageTransfer (or Namf_Communication_N1N2Transfer) service operation to send the user plane information to the AMF in the NAS container, instructing the UE to use a TLS-based user plane for location.

[0104] Optionally, the LMF can assign an LCS-UP binding ID to associate the user plane connection to be established with the target terminal device, and include this LCS-UP binding ID in the user plane information. The LMF can associate the identifier of the target terminal device with this LCS-UP binding ID. The identifier of the terminal device may include a subscription permanent identifier (SUPI) and / or a generic public subscription identifier (GPSI).

[0105] Optionally, if the terminal device supports user plane positioning and the AMF does not subscribe to the state of the LCS user plane connection, the AMF can subscribe to the state of the LCS user plane connection from the LMF.

[0106] In step S503, the AMF forwards the user plane information. When the AMF receives the user plane information from the LMF in step S502, the AMF can send the user plane information to the terminal device via a DL NAS TRANSPORT message.

[0107] In step S504, the terminal device establishes a user plane connection. If no established PDU session suitable for user plane positioning exists, the terminal device can use the User Routing Selection Policy (URSP) defined in TS23.503

[0041] to establish a PDU session for user plane positioning. The URSP may include PDU session parameters related to user plane positioning. PDU session parameters may include, for example, the Distributed Network Name (DNN) and S-NSSAI.

[0108] Optionally, the terminal device can establish a secure user plane connection with the LMF. If the LMF sends a fully qualified domain name (FQDN) to the terminal device, a Domain Name System (DNS) server / resolver is used to resolve the LMF's IP address. The DNS server could be, for example, an edge application server discovery function (EASDF) or a local DNS used for local LMF address resolution.

[0109] Optionally, after successfully establishing a secure user plane connection, the terminal device can send the LCS-UP binding ID received in step S503 to the LMF through the secure user plane connection, so that the LMF can perform the association between the terminal device and the secure user plane connection. Once the association between the terminal device and the user plane connection is completed, the LCS-UP binding ID will be released.

[0110] In step S505, the terminal device sends a user plane positioning acknowledgement. The terminal device can send an acknowledgement to the LMF via the AMF to indicate that the user plane connection was successfully established, or to indicate that the user plane connection defined in TS24.572

[0048] cannot be used. Optionally, the terminal device can send the acknowledgement via UL NAS TRANSPORT.

[0111] In step S506, the AMF forwards the acknowledgment. The AMF can send the acknowledgment received in step S505 to the LMF via the Namf_N1messageNotify service.

[0112] In step S507, the LMF notifies the AMF. The LMF can indicate to the AMF in the Nlmf_Location_UPNotify message that a user plane connection between the terminal device and the LMF has been established.

[0113] In step S508, the AMF stores the LCS-UP connection context. Optionally, the AMF may store the LCS-UP connection context as part of the UE context.

[0114] In step S509, the terminal device transmits UE positioning and supplementary service messages via the user plane, such as the LTE positioning protocol (LPP) and supplementary service message transmission. If the LMF or the terminal device decides to use a user plane connection for positioning and a secure user plane connection has been established, LPP messages are transmitted between the terminal device and the LMF for interaction based on the terminal device's positioning, terminal device-assisted positioning, and supplementary data.

[0115] Optionally, supplementary service messages may include event reporting messages, periodically triggered call messages, and MS cancel delay location messages. Supplementary service messages can also be transmitted between the LMF and the terminal device via an established user plane connection.

[0116] Figure 6 is a schematic diagram of a process for a terminal device to trigger the establishment of a user plane connection. The dashed lines in Figure 6 indicate that this process is optional.

[0117] Referring to Figure 6, in step S601, the terminal device sends a user plane connection establishment request. If a secure user plane connection has not been established between the terminal device and the LMF, and the terminal device decides to request a user plane connection for an upcoming positioning request, the terminal device can send a user plane connection establishment request to the AMF via a NAS message. Optionally, the terminal device can send user plane positioning initiation information via UL NAS TRANSPORT.

[0118] In step S602, the AMF performs LMF selection. If the terminal device is authorized to use user plane positioning based on its subscription, the AMF selects an LMF capable of establishing a user plane session with the terminal device for positioning. The AMF can discover and select a suitable LMF by querying the network repository function (NRF) or based on local configuration.

[0119] In step S603, the AMF sends an Nlmf_Location_UPConfig request to the LMF to request the establishment of an LCS-UP connection. The AMF should include the target terminal device identifier (see TS29.572

[0012] ) (SUPI and / or GPSI) in the request.

[0120] In step S604, the LMF sends user plane information to the AMF. For example, it calls `Namf_Communication_N1N2MessageTransfer` to send user plane information. Optionally, if the LMF accepts the use of the user plane for positioning, and a secure user plane connection has not been established between the terminal device and the LMF, the LMF sends user plane information to the AMF, instructing the terminal device to accept and use the user plane for positioning. The user plane information may include the LMF's user plane positioning address. The LMF may assign an LCS-UP binding ID to associate the user plane connection to be established with the target terminal device and include the LCS-UP binding ID in the user plane information. The LMF may associate the target terminal device identifier (SUPI and / or GPSI) with the LCS-UP binding ID.

[0121] In step S605, when the AMF receives the user plane information sent by the LMF in step S604, the AMF forwards it to the terminal device via a DL NAS TRANSPORT message.

[0122] In step S606, the terminal device establishes a user plane connection. If a secure user plane connection has not yet been established, the terminal device establishes a secure user plane connection with the LMF. The terminal device can use the LMF's user plane location address and information in the URSP to determine the PDU session parameters, including DNN+S-NSSAI. The terminal device can use the PDU session parameters to establish a PDU session. When the SMF receives a request, it selects a suitable UPF based on DNN+S-NSSAI and establishes a connection between the UPF and the LMF. After successfully establishing a secure user plane connection, the terminal device sends the LCS-UP binding ID received in step S604 to the LMF through the secure user plane connection, enabling the LMF to perform the association between the terminal device and this secure user plane connection. Once the association is complete, the LCS-UP binding ID will be released.

[0123] In step S607, the terminal device sends an acknowledgment to the LMF via the AMF, indicating that the user plane connection was successfully established, or indicating that the user plane connection defined in TS24.572

[0048] cannot be used.

[0124] In step S608, the AMF sends the acknowledgment received in step S607 to the LMF via the Namf_N1messageNotify service.

[0125] In step S609, the LMF responds to the AMF, indicating that a user plane connection has been established between the terminal device and the LMF.

[0126] In step S610, the AMF stores the LCS-UP connection context as part of the UE context.

[0127] In step S611, after establishing a secure user plane connection, if the LMF decides to use the user plane connection for positioning after receiving the positioning request from the AMF, or if the terminal device decides to use the user plane connection for positioning, then an LPP message is transmitted between the terminal device and the LMF for positioning based on the terminal device, terminal device-assisted positioning, and delivery of auxiliary data.

[0128] Referring to the user plane configuration and data transmission flow shown in Figures 5 and 6, it can be seen that in some cases of location services, a user plane connection needs to be established between the terminal device and the core network for user plane data transmission. However, depending on changes in network conditions, terminal location, or quality of service requirements, an LMF relocation process may be performed, that is, migrating the LMF from one network node to another. The LMF relocation process is illustrated below with reference to Figure 7.

[0129] Figure 7 is a schematic diagram of an LMF relocation process. The dashed lines in Figure 7 indicate that this process is optional.

[0130] Referring to Figure 7, in step S701, the source LMF network element sends an Nlmf_Location_UPNotify message to the AMF network element. In some embodiments, the source LMF network element can use the Nlmf_Location_UPNotify message to instruct the AMF network element to establish or terminate a user plane connection.

[0131] If the Nlmf_Location_UPNotify message indicates a request to establish a user plane connection, the Nlmf_Location_UPNotify message may include the identifier of the target LMF network element. The AMF's address is provided to the target LMF as the "notification target address" in the latest Nlmf_Location_UPConfig message or Nlmf_Location_UP Subscribe message.

[0132] If the Nlmf_Location_UPNotify message indicates termination of the user plane connection, steps S701, S704, S707, and S708 are executed, and other steps are skipped. It should be understood that if the source LMF element requests termination of the user plane connection, the AMF releases the LCS-UP context.

[0133] In some implementations, when the source LMF detects that it needs to modify the LMF, re-establish the user plane connection between the terminal device and the LMF, or terminate the user plane connection, it can send an Nlmf_Location_UPNotify message to the AMF network element.

[0134] In some implementations, after receiving an event report from the terminal device via the user plane, or after receiving AMF relocation information from the target AMF, the source LMF can determine whether it needs to modify the LMF, re-establish the user plane connection between the terminal device and the LMF, or terminate the user plane connection. For example, if the source LMF finds that the current LMF needs to be modified, the target LMF can obtain the terminal device's LCS-UP context from the source LMF. This context indicates that the terminal device has maintained an LCS-UP connection with the source LMF. The target LMF can use the Nlmf_Locatoion_UPConfig request message to notify the source LMF of the AMF change information.

[0135] It should be noted that the LMF modification process is independent of the session and service continuity mode (SSC) of the PDU session used for location in the dedicated DNN. For SSC modes 2 / 3, the PDU session anchor (PSA) UPF connection to the LMF can be relocated as the terminal device moves, and the source LMF can detect the need to modify the LMF to reduce user plane path latency.

[0136] In step S702, the AMF triggers LMF reselection. Based on the target LMF identifier received from the source LMF for user plane positioning, or if the terminal device moves to a new location (potentially outside the service area of ​​the source LMF but within the service area of ​​the target LMF), the AMF can perform LMF reselection and select a target LMF for the current terminal device's location based on the LMF service area, LMF user plane positioning capability information, and other information (such as that listed in Clause 5.1 of specification TS23.273). The target LMF needs to be able to establish a user plane session with the terminal device for positioning. In some implementations, after AMF relocation, if the source LMF does not perform LMF reselection, the target LMF can trigger LMF reselection and LCS-UP connection modification procedures.

[0137] In step S703, the network node is migrated to the target LMF. For example, a network node migration can be performed between the AMF (or target AMF), the terminal device, and the target LMF, and the connection is moved to the target LMF. It should be understood that the UE can terminate the connection with the source LMF.

[0138] In step S704, the AMF sends an Nlmf_Location_UPConfig Request message to the source LMF. This request message may include a request for the source LMF to terminate a specific user plane connection with the terminal device, and an identifier of the target LMF. Alternatively, the request message may also include information about AMF relocation. It should be understood that AMF relocation does not always lead to LMF reselection; simply notifying the LMF of the AMF relocation information is sufficient.

[0139] In step S705, if there is a context for periodic location reports based on the user plane or for triggering event location reports, the source LMF can call Nlmf_Location_LocationContextTransfer to request a service operation from the target LMF to provide the current location context of the terminal device.

[0140] In step S706, the target LMF sends an Nlmf_Location_LocationContextTransfer Response to the source LMF to notify the source LMF of the result of the terminal device location context transfer operation in step S705.

[0141] In step S707, if the user plane connection between the terminal device and the source LMF is still active, the source LMF may terminate the direct user plane connection with the terminal device.

[0142] In step S708, the source LMF sends an Nlmf_Location_UPConfig response message to the AMF to acknowledge connection termination or confirm AMF changes. If this procedure is used for termination, the AMF will release the LCS-UP context upon receiving the response message.

[0143] As described above, current positioning and sensing services transmit data via user plane connections, and any LMF (Local Multi-Function) and terminal device can trigger the establishment of a user plane connection (see Figures 5 and 6 for related descriptions). However, there is currently no mechanism to limit the number of user plane connections established or to reject requests exceeding the limit. In other words, how to manage user plane connections is a technical problem that urgently needs to be solved.

[0144] To address the aforementioned issues, embodiments of this application will be described below.

[0145] The first connection and / or second connection mentioned in the various embodiments of this application can be a connection established between the terminal device and the core network for transmitting service data of the terminal device. This first connection and / or second connection can be a user plane connection, or other connections with similar functions introduced in future communication systems.

[0146] This application proposes a communication method in which a terminal device can control the connection between itself and core network elements based on the maximum number of connections it is allowed to establish, thereby facilitating connection management (such as limiting the number of connections established and rejecting connection establishment requests exceeding the allowed number). The embodiments of this application are described in detail below with reference to the accompanying drawings.

[0147] Figure 8 is a schematic flowchart of the communication method provided in an embodiment of this application. The method in Figure 8 is described from the perspective of the terminal device. The terminal device in Figure 8 can be the terminal device 120 in Figure 1.

[0148] Referring to Figure 8, in step S810, the terminal device receives a first message. The first message can be used to request the establishment of a first connection between the terminal device and the first core network element.

[0149] In this application, the first message can be a message sent from the first core network element to the terminal device, or a message sent from the second core network element to the terminal device. Alternatively, it can be a message sent from the first core network element to the second core network element and then forwarded by the second core network element to the terminal device.

[0150] In some implementations, the first core network element can be an NF2 network element. An NF2 network element can be a service processing network element, such as a network element for collecting / processing sensing data or a network element for collecting / processing location data. An NF2 network element can be, for example, an LMF network element or an SF network element. In some implementations, NF2 can include NF2a and NF2b, which are different instances or sub-modules of NF2 (such as UPF or LMF). In some implementations, in a location scenario, NF2a may be responsible for data acquisition, while NF2b may be responsible for data processing.

[0151] In some implementations, the second core network element can be an NF1 network element, which can be a control plane signaling forwarding network element. For example, the NF1 network element can be an AMF network element in 5G or a mobility management (MM) network element in 6G.

[0152] In some implementations, the terminal device can transmit location service data through the first connection. In other implementations, the terminal device can also transmit sensing service data through the first connection; this application does not impose specific limitations on this.

[0153] In step S820, the terminal device determines whether to establish the first connection based on the maximum number of connections allowed to be established by the terminal device.

[0154] In some implementations, considering factors such as terminal device load, security and privacy protection, and specific network implementation, the maximum number of connections allowed to be established by the terminal device can be limited. For example, the maximum number of connections allowed to be established by the terminal device can be limited to n, where n is a positive integer. For instance, the maximum number of connections allowed to be established by the terminal device can be limited to one, or it can be limited to multiple.

[0155] In this application, the terminal device can control the connection between the terminal device and the first core network element according to the maximum number of connections it is allowed to establish, thereby helping to manage the connection (such as limiting the number of connections established and rejecting connection establishment requests that exceed the limit).

[0156] Please consider that core network element relocation (such as LMF or SF reselection) will trigger connection establishment requests. The core network system cannot distinguish between connection establishment requests triggered by relocation and those for new connections, thus creating problems in limiting the number of connections. In other words, the problem to be solved is how to implement a maximum connection limit (e.g., rejecting more than n connection establishment requests) and accept connection establishment requests triggered by core network element relocation while maintaining the maximum connection limit.

[0157] In this application, the first message may contain information for determining the connection type of the first connection. The connection type of the first connection includes: the first connection is a newly established connection, or the first connection is a connection established based on a relocation trigger of a core network element. The first message may be, for example, a NAS message, a control plane message, or user plane configuration information. In some implementations, the user plane configuration information may include user plane information and information for determining the connection type of the first connection (i.e., connection type indication information). For example, the user plane information may include user plane address information of a core network element (such as NF2), FQDN, IP address, user plane ID information, etc. FQDN may refer to the fully qualified domain name identifier of a network function, used to resolve IP addresses in DNS (Domain Name System). IP address may refer to the unique identifier of a network function, used to transmit data in the connection. The connection type of the first connection may be a newly established connection or a connection established based on a relocation trigger of a core network element.

[0158] In other words, in this application, the terminal device can determine whether to establish a first connection based on the maximum number of connections and / or the connection type.

[0159] As an example, if the number of connections established by the terminal device does not exceed the maximum number of connections, or if the first connection is a connection established based on relocation triggering, then the terminal device can establish the first connection.

[0160] As another example, if the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection, the terminal device may refuse to establish the first connection.

[0161] As can be seen, this application determines whether to establish the first connection based on the maximum number of connections and / or the connection type. This can both limit the maximum number of connections (e.g., reject more than n connection establishment requests) and accept connection establishment requests caused by the relocation of core network elements (e.g., LMF or SF elements) while maintaining the maximum number of connections limit.

[0162] In some implementations, if the terminal device refuses to establish the first connection, the terminal device can send a first parameter to the first core network element. The first parameter can be used to indicate that the reason why the terminal device refuses to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

[0163] The value of the first parameter can be the reason for the failure to establish the first connection. The value of the first parameter can be used to indicate the reason why the terminal device refuses to establish the first connection (i.e. the reason why the first connection failed to establish) is because the maximum number of connections has been exceeded.

[0164] In some implementations, the first parameter can be carried in a response message sent by the terminal device to the first core network element regarding whether the first connection was successfully established.

[0165] In some implementations, if the terminal device accepts and establishes the first connection, the terminal device sends a second parameter to the first core network element. The second parameter can be used to indicate that the first connection was successfully established. The value of the second parameter can be an indication of successful first connection establishment. In some implementations, the first parameter and the second parameter can be the same parameter. For example, the first parameter can include multiple values, including a reason value for failure of first connection establishment and an indication value for successful first connection establishment.

[0166] In some implementations, the indication message for the failure of the first connection establishment may include a new cause value, which can be used to indicate that the failure of the first connection establishment is due to the connection exceeding the maximum number of connections.

[0167] In some other implementations, if the maximum number of connections that a terminal device is allowed to establish is limited to 1, the indication message for the failure of the first connection establishment includes a reason value, which can be used to indicate that the failure of the first connection establishment is due to the existence of an existing connection.

[0168] In some implementations, the reason value used to indicate connection establishment failure can be a new value added to the existing reason values ​​to identify the reason for connection establishment failure. For example, the current reason value can include 01 and 10 to identify two reasons for user plane establishment failure. In this application, a new reason value (such as 11) can also be added to identify a new reason for user plane establishment failure. Of course, a new variable can also be added to indicate a new reason for the first connection establishment failure.

[0169] This application does not impose specific restrictions on the method of indicating the connection type of the first connection. For example, the connection type of the first connection can be explicitly indicated by the first message; or the connection type of the first connection can be implicitly indicated by the first message.

[0170] As an example, the first message contains explicit first indication information, which indicates the connection type of the first connection. For instance, if the first indication information is a first value, it indicates that the first connection is a newly established connection; if the first indication information is a second value, it indicates that the first connection is a connection established based on relocation triggering. For example, the first value can be 0 or 1, and correspondingly, the second value can be 1 or 0; of course, the first and second values ​​can also be other values. Similarly, if the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection is a connection established based on relocation triggering.

[0171] As another example, the first message contains implicit second indication information, which can be used to determine the connection type of the first connection. The second indication information includes information about the source core network element (such as the source NF2 element) associated with the relocation and / or information about the user plane address of the terminal device and the source core network element (such as the source NF2 element). For example, if the connection request contains the second indication information, it can be determined that the first connection is a connection established based on relocation triggering; if the connection request does not contain the second indication information, it can be determined that the first connection is a newly established connection.

[0172] It should be noted that if the terminal device determines that a connection is in a relocation state based on the connection type indication information, the connection count is recorded as 1. If the maximum number of connections is limited to 1, then only connection establishment requests triggered by relocation will be accepted for that connection. For example, if the maximum number of connections is limited to 1, and a connection (such as the second connection, which is a connection between the terminal device and the source core network element associated with relocation) is in a relocation state, then only connection establishment requests triggered by relocation corresponding to that connection (such as the first connection) can be accepted.

[0173] In some implementations, if the first connection is established based on relocation triggering, after the first connection is established, the terminal device can trigger the process of releasing the second connection to release the second user plane link. The second connection is the connection between the terminal device and the source core network element associated with relocation.

[0174] In some other implementations, if the first connection is a connection established based on relocation triggering, the terminal device can trigger a process to release the second user plane link before establishing the first connection. The second connection is the connection between the terminal device and the source core network element associated with the relocation.

[0175] The above describes the scheme by which the terminal device determines whether to establish the first connection based on the maximum number of connections and / or the connection type. The following, with reference to Figure 9, provides a further example of the scheme from the perspective of the interaction between the core network element and the terminal device.

[0176] Referring to Figure 9, in step S901, the first core network element sends a first message to the second core network element. The first message requests the establishment of a first connection between the terminal device and the first core network element. The first message includes information for determining the connection type of the first connection and user plane information. For example, the first message sent by the first core network element to the second core network element can be called user plane configuration information.

[0177] In step S902, the second core network element sends a first message to the terminal device. The first message sent by the second core network element to the terminal device can be called a control plane message.

[0178] In step S903, after receiving the first message, the terminal device can determine the connection type of the first connection based on the connection type information in the first message. For example, the first connection can be a newly established connection or a connection triggered by the relocation of a core network element. After determining the connection type of the first connection, the terminal device can decide whether to establish the first connection based on the maximum number of connections and / or the connection type.

[0179] For example, if the number of connections established by the terminal device does not exceed the maximum number of connections, or if the first connection is a connection established based on relocation triggering, then the terminal device establishes the first connection.

[0180] For example, if the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection, then the terminal device will refuse to establish the first connection.

[0181] In step S904a, if the terminal device successfully establishes the first connection, it can send a response message to the second core network element, which can be used to indicate that the first connection has been successfully established.

[0182] In step S904b, the second core network element sends the response message from step S904a to the first core network element.

[0183] In step S904c, if the first connection is established based on the relocation trigger of a core network element, the terminal device will trigger the release of the relocation source connection. It should be understood that the terminal device may also trigger the release of the relocation source connection before successfully establishing the first connection. That is, the timing of the terminal device triggering the release of the relocation source connection can occur before or after step S904a; this application does not impose specific limitations on this.

[0184] In step S905a, if the terminal device refuses to establish the first connection, it can send a response message to the second core network element. This response message can be used to indicate that the first connection establishment failed. Of course, the response message can also include a reason for the failure of the first connection establishment. For example, the response message can include a cause value indicating that the failure of the first connection establishment was due to the connection exceeding the maximum number of connections.

[0185] In step S905b, the second core network element sends the response message from step S905a to the first core network element.

[0186] The following description, using the example of the first core network element being NF2, the second core network element being NF1, and the first connection being the user plane connection between NF2 and the terminal device, will provide a more detailed explanation of the communication method in Figure 9.

[0187] Referring to Figure 10, in step S1001, the NF2 network element sends user plane configuration information to the NF1 network element (this user plane configuration information is the first message sent by the NF2 network element to the NF1 network element). The user plane configuration information includes user plane information, connection type indication information for the first user plane connection, and source NF2 information. For example, the user plane information may include the NF2 user plane address information, FQDN, IP address, user plane ID information, etc. The connection type of the first user plane connection can be a newly established user plane connection or a user plane connection established based on the relocation trigger of a core network element.

[0188] In some implementations, the indication information for the connection type of the first user plane connection can be either the first indication information or the second indication information mentioned above. The indication information for the connection type of the first user plane connection can be a single indication information (this single indication information can be explicit indication information, such as the first indication information mentioned above). For example, if the connection request of the first user plane connection carries this single indication information, it indicates that the first user plane connection is a newly established user plane connection; if it does not carry this single indication information, it indicates that the user plane connection is established based on the relocation trigger of the core network element. Conversely, if it carries this single indication information, it indicates that the first user plane connection is established based on the relocation trigger of the core network element; if it does not carry this single indication information, it indicates that the first user plane connection is a newly established user plane connection. Alternatively, the connection type of the first user plane connection may be identified implicitly. For example, the connection type indication information of the first user plane connection may carry information about the source NF2 (such as the second indication information mentioned above). If the connection request of the first user plane connection carries source NF2 information, it means that the first user plane connection is a user plane connection established based on the relocation trigger of the core network element. If it does not carry source NF2 information, it means that the first user plane connection is a newly established user plane connection.

[0189] In step S1002, NF1 sends a control plane message to the terminal device (the control plane message is the first message sent by the NF1 network element to the terminal device), wherein the control plane message includes the user plane information in step S1001 and the connection type indication information of the first user plane connection.

[0190] In some implementations, the information sent by NF2 network element to NF1 network element to determine the connection type of the first user plane connection may be implicit indication information (e.g., whether it carries the source NF2). Based on this implicit indication information, NF1 network element can send explicit indication information (such as the single indication information mentioned above) to the terminal device to indicate the connection type of the first user plane connection. Of course, NF1 network element can also directly forward the connection type indication information of the first user plane connection included in the user plane configuration information in step S1001.

[0191] In some implementations, NF1 network elements can communicate with terminal equipment via the RAN. Control plane messages between the terminal equipment and the RAN can be referred to as NAS messages.

[0192] In step S1003, after receiving the connection request to establish the first user plane connection, the terminal device can determine whether to establish the first user plane connection based on the maximum number of user plane connections and / or the connection type.

[0193] For example, if the number of user plane connections established by the terminal device does not exceed the maximum number of user plane connections, or if the first user plane connection is a user plane connection established based on relocation triggering, then the terminal device establishes the first user plane connection.

[0194] For example, if the number of user plane connections established by the terminal device exceeds the maximum number of user plane connections, and the first user plane connection is a newly established user plane connection, then the terminal device refuses to establish the first user plane connection.

[0195] In step S1004a, if the terminal device determines that it accepts the connection request for the first user plane connection, it establishes the first user plane connection and sends a successful establishment indication message to the NF2 network element through the NF1 network element. It should be understood that the terminal device can communicate with the NF1 network element through the RAN. The successful establishment indication message between the terminal device and the RAN can be referred to as a NAS message.

[0196] In step S1004b, NF1 network element sends a first user plane connection establishment success indication message to NF2 network element. The first user plane connection establishment success indication message can be called a response message between NF1 network element and NF2 network element.

[0197] In step S1004c, if the connection request for the first user plane connection is a user plane connection request established based on a relocation trigger, the terminal device will trigger the release of the relocation source user plane connection. It should be understood that the terminal device may also trigger the release of the relocation source user plane connection before successfully establishing the first user plane connection. That is, the timing of the terminal device triggering the release of the relocation source user plane connection can occur before or after step S1004a; this application does not impose specific limitations on this.

[0198] In step S1005a, if the terminal device determines that it rejects the request to establish the first user plane connection, it can send an indication message indicating that the establishment of the first user plane connection failed to the NF2 network element through the NF1 network element. Of course, this indication message may also include the reason for the failure of the first user plane connection establishment. For example, the indication message may include a cause value indicating the failure of the first user plane connection establishment, such as indicating that the failure was due to the user plane connections exceeding the maximum number of user plane connections.

[0199] It should be understood that terminal devices can communicate with NF1 network elements through the RAN. The indication message indicating a first user plane connection establishment failure can be referred to as a NAS message between the terminal device and the RAN.

[0200] In some implementations, the indication message for the failure of establishing the first user plane connection may include a new cause value. This new cause value can be used to indicate that the failure was due to the user plane connections exceeding the maximum number of user plane connections. In some implementations, the new cause value can be a value added to an existing cause value to identify the reason for the failure. For example, the current cause values ​​may include 01 and 10 to identify two reasons for user plane connection failure. In this application, a new cause value (such as 11) can also be added to identify a new reason for the failure. Alternatively, a new variable can be added to indicate the new reason for the failure of the first user plane connection.

[0201] In step S1005b, NF1 network element sends a first user plane connection establishment failure indication message to NF2 network element. The first user plane connection establishment failure indication message can be called a response message between NF1 network element and NF2 network element.

[0202] The preceding text detailed a scheme where the terminal device determines whether to establish the first connection based on the maximum number of connections allowed to be established by the terminal device. However, the decision-making body for establishing the first connection may not be the terminal device itself; for example, it can be made by a core network element based on the maximum number of connections allowed to be established by the terminal device. The following section, with reference to accompanying figures, details a scheme based on a core network element for determining whether to establish the first connection.

[0203] Figure 11 is a schematic flowchart of the communication method provided in an embodiment of this application. The method in Figure 11 is described from the perspective of the interaction between the first core network element and the second core network element. The communication method in Figure 11 is described below from the perspective of the second core network element.

[0204] Referring to Figure 11, in step S1110, the second core network element receives a second message sent by the first core network element. The second message is used to request the establishment of a first connection between the terminal device and the first core network element.

[0205] In this application, the second message can be a message sent from the first core network element to the second core network element, and the first message mentioned above can be a message sent from the core network element to the terminal device. The first message and the second message can be the same or different, and this application does not impose specific restrictions on their comparison.

[0206] In some implementations, the first core network element can be an NF2 network element. An NF2 network element can be a service processing network element, such as a network element for collecting / processing sensing data or a network element for collecting / processing location data. An NF2 network element can be, for example, an LMF network element or an SF network element. In some implementations, NF2 can include NF2a and NF2b, which are different instances or sub-modules of NF2 (such as UPF or LMF). In some implementations, in a location scenario, NF2a may be responsible for data acquisition, while NF2b may be responsible for data processing.

[0207] In some implementations, the second core network element can be an NF1 network element, which can be a control plane signaling forwarding network element. For example, the NF1 network element can be an AMF network element in 5G or an MM network element in 6G.

[0208] In some implementations, the first connection is used to transmit positioning service data, or it can be used to transmit sensing service data; this application does not impose any specific restrictions on this.

[0209] In step S1120, the second core network element determines whether the terminal device is allowed to establish the first connection based on the maximum number of connections that the terminal device is allowed to establish.

[0210] In some implementations, considering factors such as terminal device load, security and privacy protection, and specific network implementation, the maximum number of connections allowed to be established by the terminal device can be limited. For example, the maximum number of connections allowed to be established by the terminal device can be limited to n, where n is a positive integer. For instance, the maximum number of connections allowed to be established by the terminal device can be limited to one, or it can be limited to multiple.

[0211] In this application, the terminal device can control the connection between the terminal device and the first core network element according to the maximum number of connections it is allowed to establish, thereby helping to manage the connection (such as limiting the number of connections established and rejecting connection establishment requests that exceed the limit).

[0212] In this application, the second message may contain information for determining the connection type of the first connection. The connection type of the first connection includes: the first connection is a newly established connection, or the first connection is a connection established based on a relocation trigger of a core network element. The second message may, for example, be user plane configuration information. In some implementations, the user plane configuration information may include user plane information and information for determining the connection type of the first connection (i.e., connection type indication information). For example, the user plane information may include user plane address information of a core network element (such as NF2), FQDN, IP address, user plane ID information, etc. FQDN may refer to the fully qualified domain name identifier of a network function, used to resolve IP addresses in DNS (Domain Name System). IP address may refer to the unique identifier of a network function, used to transmit data in the connection. The connection type of the first connection may be a newly established connection or a connection established based on a relocation trigger of a core network element.

[0213] In other words, the second core network element in this application can determine whether the terminal device is allowed to establish the first connection based on the maximum number of connections and / or the connection type.

[0214] As an example, if the number of connections established by the terminal device does not exceed the maximum number of connections, or if the first connection is a connection established based on relocation trigger, then the second core network element determines that the terminal device is allowed to establish the first connection.

[0215] As another example, if the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection, then the second core network element determines that the terminal device is not allowed to establish the first connection.

[0216] In some implementations, if the second core network element determines that the terminal device is not allowed to establish the first connection, the second core network element sends a first parameter to the first core network element. The first parameter is used to indicate the reason for refusing to establish the first connection: the number of connections established by the terminal device exceeds the maximum number of connections.

[0217] In some other implementations, if the maximum number of connections that a terminal device is allowed to establish is limited to 1, and the second core network element determines that the terminal device is not allowed to establish the first connection, then the second core network element sends a first parameter to the first core network element. The first parameter can also be used to indicate the reason for refusing to establish the first connection: a connection already exists.

[0218] If the second core network element refuses to establish the first connection, the second core network element can send a first parameter to the first core network element. The first parameter can be used to indicate that the reason why the second core network element refuses to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

[0219] The value of the first parameter can be the reason why the first connection failed to be established. The value of the first parameter can be used to indicate that the second core network element refused to establish the first connection because the maximum number of connections was exceeded.

[0220] In some implementations, the reason value used to indicate connection establishment failure can be a new value added to the existing reason values ​​to identify the reason for connection establishment failure. For example, the current reason value can include 01 and 10 to identify two reasons for user plane establishment failure. In this application, a new reason value (such as 11) can also be added to identify a new reason for user plane establishment failure. Of course, a new variable can also be added to indicate a new reason for the first connection establishment failure.

[0221] In some implementations, the indication message for the first connection establishment failure may include a new cause value, which can be used to indicate that the first connection establishment failure was due to exceeding the maximum number of connections. In some implementations, the new cause value may be a value added to an existing cause value to identify the reason for the connection establishment failure. For example, the current cause values ​​may include 01 and 10 to identify two reasons for user plane establishment failure. In this application, a new cause value (such as 11) may also be added to identify a new reason for user plane establishment failure. Of course, a new variable may also be added to indicate the new reason for the first connection establishment failure.

[0222] In some implementations, the first parameter can be carried in a response message sent by the second core network element to the first core network element, indicating whether the terminal device is allowed to establish the first connection.

[0223] It should be noted that if a second core network element determines, based on the context, that a connection is currently in a relocation state, it records the connection count as 1, and only accepts connection establishment requests triggered by relocation for that connection. For example, if the maximum number of connections is limited to 1, and a connection is in a relocation state, only connection establishment requests triggered by relocation for that connection can be accepted.

[0224] This application does not impose specific restrictions on the method of indicating the connection type of the first connection. For example, the connection type of the first connection can be explicitly indicated by the second message; or the connection type of the first connection can be implicitly indicated by the second message.

[0225] As an example, the second message contains explicit first indication information, which indicates the connection type of the first connection. For instance, if the first indication information is a first value, it indicates that the first connection is a newly established connection; if the first indication information is a second value, it indicates that the first connection is a connection established based on relocation triggering. For example, the first value can be 0 or 1, and correspondingly, the second value can be 1 or 0; of course, the first and second values ​​can also be other values. Similarly, if the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection is a connection established based on relocation triggering.

[0226] As another example, the second message contains implicit second indication information, which can be used to determine the connection type of the first connection. The second indication information includes information about the source core network element (such as the source NF2 element) associated with the relocation and / or information about the user plane address of the terminal device and the source core network element (such as the source NF2 element). For example, if the connection request contains the second indication information, it can be determined that the first connection is a connection established based on relocation triggering; if the connection request does not contain the second indication information, it can be determined that the first connection is a newly established connection.

[0227] The above describes the scheme by which the second core network determines whether a terminal device is allowed to establish a first connection based on the maximum number of connections and / or the connection type. The following, with reference to Figure 12, provides a further example of the scheme from the perspective of the interaction between core network elements and terminal devices.

[0228] Referring to Figure 12, in step S1201, the first core network element sends a second message to the second core network element. The second message requests the establishment of a first connection between the terminal device and the first core network element. The second message includes information for determining the connection type of the first connection and user plane information. For example, the second message sent by the first core network element to the second core network element can be called user plane configuration information.

[0229] In step S1202, after receiving the second message, the second core network element can determine the connection type of the first connection based on the connection type information in the second message. For example, the first connection can be a newly established connection or a connection established based on a relocation trigger of the core network element. After determining the connection type of the first connection, the second core network element can determine whether the terminal device allows the establishment of the first connection based on the maximum number of connections and / or the connection type.

[0230] For example, if the number of connections established by the terminal device does not exceed the maximum number of connections, or if the first connection is a connection established based on relocation trigger, then the second core network element determines that the terminal device is allowed to establish the first connection.

[0231] For example, if the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection, then the second core network element determines that the terminal device is not allowed to establish the first connection.

[0232] It should be noted that if a second core network element determines, based on the context, that a connection is currently in a relocation state, it records the connection count as 1, and only accepts connection establishment requests triggered by relocation for that connection. For example, if the maximum number of connections is limited to 1, and a connection is in a relocation state, only connection establishment requests triggered by relocation for that connection can be accepted.

[0233] In step S1203a, if the second core network element determines that the terminal device allows the establishment of the first connection, it sends a second message to the terminal device. The second message sent by the second core network element to the terminal device can be called a control plane message.

[0234] In step S1203b, if the terminal device successfully establishes the first connection, it can send a response message to the second core network element, which can be used to indicate that the first connection has been successfully established.

[0235] In step S1203c, the second core network element sends the response message from step S1204a to the first core network element.

[0236] In step S1204, if the second core network element determines that the terminal device is not allowed to establish the first connection, the second core network element sends a first parameter to the first core network element. The first parameter is used to indicate the reason for refusing to establish the first connection: the number of connections established by the terminal device exceeds the maximum number of connections.

[0237] The value of the first parameter can be the reason why the first connection failed to be established. The value of the first parameter can be used to indicate that the second core network element refused to establish the first connection because the maximum number of connections was exceeded.

[0238] In some other implementations, if the maximum number of connections that a terminal device is allowed to establish is limited to 1, and the second core network element determines that the terminal device is not allowed to establish the first connection, then the second core network element sends a first parameter to the first core network element. The first parameter can also be used to indicate the reason for refusing to establish the first connection: a connection already exists.

[0239] In some implementations, the indication message for the first connection establishment failure may include a new cause value, which can be used to indicate that the first connection establishment failure was due to exceeding the maximum number of connections. In some implementations, the new cause value may be a value added to an existing cause value to identify the reason for the connection establishment failure. For example, the current cause values ​​may include 01 and 10 to identify two reasons for user plane establishment failure. In this application, a new cause value (such as 11) may also be added to identify a new reason for user plane establishment failure. Of course, a new variable may also be added to indicate the new reason for the first connection establishment failure.

[0240] In some implementations, the first parameter can be carried in a response message sent by the second core network element to the first core network element, indicating whether the terminal device is allowed to establish the first connection.

[0241] The following description, using the example of the first core network element being NF2, the second core network element being NF1, and the first connection being the connection between NF2 and the terminal device, will provide a more detailed explanation of the communication method in Figure 12.

[0242] Referring to Figure 13, in step S1301, the NF2 network element sends user plane configuration information to the NF1 network element (this user plane configuration information is the second message sent by the NF2 network element to the NF1 network element). The user plane configuration information includes user plane information, connection type indication information for the first user plane connection, and source NF2 information. For example, the user plane information may include the NF2 user plane address information, FQDN, IP address, user plane ID information, etc. The connection type of the first user plane connection can be a newly established user plane connection or a user plane connection established based on the relocation trigger of a core network element.

[0243] In some implementations, the indication information for the connection type of the first user plane connection can be either the first indication information or the second indication information mentioned above. The indication information for the connection type of the first user plane connection can be a single indication information (this single indication information can be explicit indication information, such as the first indication information mentioned above). For example, if the connection request of the first user plane connection carries this single indication information, it indicates that the first user plane connection is a newly established user plane connection; if it does not carry this single indication information, it indicates that the user plane connection is established based on the relocation trigger of the core network element. Conversely, if it carries this single indication information, it indicates that the first user plane connection is established based on the relocation trigger of the core network element; if it does not carry this single indication information, it indicates that the first user plane connection is a newly established user plane connection. Alternatively, the connection type of the first user plane connection may be identified implicitly. For example, the connection type indication information of the first user plane connection may carry information about the source NF2 (such as the second indication information mentioned above). If the connection request of the first user plane connection carries source NF2 information, it means that the first user plane connection is a user plane connection established based on the relocation trigger of the core network element. If it does not carry source NF2 information, it means that the first user plane connection is a newly established user plane connection.

[0244] In step S1302, after receiving the second message, the NF1 network element can determine the connection type of the first user plane connection based on the information in the second message used to determine the connection type of the first user plane connection. For example, the first user plane connection can be a newly established user plane connection or a user plane connection established based on the relocation trigger of a core network element. After determining the connection type of the first user plane connection, the NF1 network element can determine whether the terminal device is allowed to establish the first user plane connection based on the maximum number of user plane connections and / or the connection type.

[0245] For example, if the number of user plane connections established by the terminal device does not exceed the maximum number of user plane connections, or if the first user plane connection is a user plane connection established based on relocation triggering, then the NF1 network element determines that the terminal device is allowed to establish the first user plane connection.

[0246] For example, if the number of user plane connections established by the terminal device exceeds the maximum number of user plane connections, and the first user plane connection is a newly established user plane connection, then the NF1 network element determines that the terminal device is not allowed to establish the first user plane connection.

[0247] It should be noted that if an NF1 network element determines from the context that a user plane connection is currently in a relocation state, it records the user plane connection count as 1, and only accepts user plane connection establishment requests triggered by relocation for that user plane connection. For example, if the maximum number of connections is limited to 1, and a user plane connection is in a relocation state, only user plane connection establishment requests triggered by relocation for that connection can be accepted.

[0248] In step S1303a, if the NF1 network element determines that the terminal device allows the establishment of a first user plane connection, it sends a second message to the terminal device. This second message sent by the NF1 network element to the terminal device can be called a control plane message. The NF1 network element can communicate with the terminal device through the RAN. The control plane message between the terminal device and the RAN can be called a NAS message.

[0249] In step S1303b, if the terminal device successfully establishes the first user plane connection, it can send a response message to the NF1 network element. This response message can be used to indicate that the first user plane connection has been successfully established.

[0250] In step S1303c, NF1 network element sends a first user plane connection establishment success indication message to NF2 network element. The first user plane connection establishment success indication message can be called a response message between NF1 network element and NF2 network element.

[0251] In step S1304, if the NF1 network element determines that the terminal device does not allow the establishment of the first user plane connection, the NF1 network element sends an indication message indicating that the establishment of the first user plane connection has failed to be established to the NF2 network element. The indication message indicating that the establishment of the first user plane connection has failed to be established can be called a response message between the NF1 network element and the NF2 network element.

[0252] For example, if NF1 determines that the terminal device is not allowed to establish the first user plane connection, then NF1 sends a first parameter to NF2. The first parameter is used to indicate the reason for refusing to establish the first user plane connection: the number of user plane connections established by the terminal device exceeds the maximum number of user plane connections.

[0253] The value of the first parameter can be the reason for the failure to establish the first user plane connection. The value of the first parameter can be used to indicate that the reason why the NF1 network element refuses to establish the first user plane connection is because the maximum number of user plane connections has been exceeded.

[0254] In some implementations, the indication message for the first connection establishment failure may include a new cause value, which can be used to indicate that the first connection establishment failure was due to exceeding the maximum number of connections. In some implementations, the new cause value may be a value added to an existing cause value to identify the reason for the connection establishment failure. For example, the current cause values ​​may include 01 and 10 to identify two reasons for user plane establishment failure. In this application, a new cause value (such as 11) may also be added to identify a new reason for user plane establishment failure. Of course, a new variable may also be added to indicate the new reason for the first connection establishment failure.

[0255] As mentioned earlier, the second core network can determine the connection type of the first connection based on the indication information of the first plane connection type. In some implementations, the indication information of the first connection type is not required; instead, the second core network elements maintain and record connections in the relocation state to establish connections. This will be illustrated with examples below.

[0256] In some implementations, the second core network element records connections in a relocation state among those established by the terminal device. It should be understood that if the second core network element records a current connection as being in a relocation state, it can accept the relocation-triggered connection corresponding to that connection. In this case, the second core network element does not need to obtain connection type indication information and can send a user plane configuration request to the first core network element to request the release of the source connection (the connection between the terminal device and the source core network element associated with the relocation), thereby enabling the establishment of a new connection. It should be understood that the source connection can be released after the connection between the terminal device and the target core network element is established, or the source connection can be released directly without establishing a connection between the terminal device and the target core network element.

[0257] In some implementations, the connection in the relocation state among the connections established by the terminal device includes a first connection. If the second core network element receives a third message sent by the first core network element and / or the first timer times out, the second core network element determines that the migration process of the first connection has been completed. The third message is used to indicate that the first connection has been released or the migration process of the first connection has been completed, and the first timer is a timer associated with the migration process.

[0258] In some implementations, the connection established by the terminal device includes a second connection, and the second connection is in a relocation state. The target core network element of the relocation process associated with the second connection is a third core network element (such as an NF2b network element). If the second core network element (such as an NF1 network element) receives a message from the third core network element requesting the establishment of a connection, the second core network element determines that the terminal device is allowed to establish a connection.

[0259] In some implementations, the first core network element sends a third message to the second core network element, and the third message is used by the second core network element to determine the relocation status of the first connection.

[0260] In some implementations, the third information is used to indicate one or more of the following: the first connection has been released; the migration process of the first connection has been completed; the relocated target core network element and the terminal device have established or not established a new connection.

[0261] As mentioned earlier, the second core network element records the connections in the relocation state established by the terminal equipment, and performs the relocation process according to the recorded relocation state. The following is a description with reference to the attached diagram.

[0262] Referring to Figure 14, in step S1401, a first connection is established between the terminal device and the first core network element (such as NF2a).

[0263] In step S1402, the first core network element triggers a relocation process and sends a migration request to the second core network element to migrate the network node.

[0264] In step S1403, the second core network element selects the target core network element and records the target core network element for the relocation process. In some implementations, a first timer can be started simultaneously with recording the target core network element for the relocation process.

[0265] In some implementations, the target core network element can also be the target core network element indicated by the migration request message in step S1402.

[0266] In step S1404, the second core network element sends a user plane configuration request to the first core network element to request the release of the first connection between the terminal device and the first core network element or to migrate the connection of the first core network element (such as NF2a) to the target core network element (NF2b). The request contains information about the target core network element.

[0267] In step S1405, the first connection is released. It should be understood that the first connection (i.e., the source connection) can be released after the connection between the terminal device and the target core network element is established, or the first connection can be released directly without establishing a connection between the terminal device and the target core network element.

[0268] In step S1406, after the first connection is released, the first core network element replies to the second core network element with a user plane configuration response to indicate that the first connection has been released or the relocation migration has been completed.

[0269] In step S1407, if the second core network element receives a response message from the first core network element (such as the third message mentioned above), or if the set first timer has expired, then the relocation migration is recorded as complete and the relocation state ends.

[0270] The following example uses NF2a as the first core network element, NF1 as the second core network element, and NF2b as the target core network element. The first connection is the first user plane connection. The communication method in Figure 14 will be explained in more detail with reference to the example.

[0271] Referring to Figure 15, in step S1501, a first user plane connection is established between the terminal device and the NF2a network element.

[0272] In step S1502, the NF2a network element triggers the relocation process, decides to migrate the network node, and sends a migration request to the NF1 network element to migrate the network node.

[0273] In step S1503, the NF1 network element selects the NF2b network element as the target NF2 network element and records the target core network element of the relocation process as the NF2b network element. In some implementations, a first timer can be started simultaneously with recording the target core network element of the relocation process.

[0274] In some implementations, the migration request message in step S1502 may indicate that the target core network element is an NF2b network element.

[0275] In step S1504, NF1 network element sends a user plane configuration request to NF2a network element to request the release of the first user plane connection between the terminal device and NF2a network element or to migrate the connection of NF2a network element to NF2b network element. The request contains information about NF2b network element.

[0276] In step S1505, after the user plane connection of the NF2b network element is established, the first user plane connection is released; or, if the user plane connection of the NF2b network element is not established, the first user plane connection is released.

[0277] In step S1506, after the first user plane connection is released, the NF2a network element replies to the NF1 network element with a user plane configuration response to indicate that the first user plane connection has been released or the relocation migration has been completed.

[0278] In step S1507, if the NF1 network element receives a response message from the NF2a network element (such as the third message mentioned above), or if the set first timer has expired, then the relocation migration is recorded as complete and the relocation state ends.

[0279] As mentioned earlier, the source user plane connection can be released after the user plane connection between the terminal device and the target core network element is established, or the source user plane connection can be released directly without establishing a user plane connection between the terminal device and the target core network element. The following sections will explain these two scenarios in detail with reference to the accompanying diagrams.

[0280] The migration process involves establishing a user plane connection between the terminal device and the target core network element.

[0281] Referring to Figure 16, in step S1601, a first user plane connection is established between the terminal device and the first core network element.

[0282] In step S1602, the second core network element sends a user plane configuration request to the first core network element, requesting the release of the user plane connection (first user plane connection) of the first core network element or the migration of the user plane connection of the first core network element to the target core network element (such as NF2b). The request contains information about the target core network element.

[0283] In step S1603, the first core network element sends a context transmission request to the target core network element to migrate the context of a portion of the session.

[0284] In step S1604, the target core network element sends a context transmission response to the first core network element, which includes indication information on whether to establish a user plane connection.

[0285] In step S1605, if the target core network element indicates that a user plane connection needs to be established, the first core network element waits for the user plane connection release process triggered by the terminal device, or sets a timer to wait for the user plane connection release to be triggered.

[0286] In step S1606, the user plane connection establishment process between the target core network element and the terminal equipment is initiated.

[0287] In step S1607, after the user plane connection of the target core network element is established, the terminal device triggers the user plane connection release process with the first core network element.

[0288] In step S1608, the user plane connection release process between the first core network element and the terminal device is initiated.

[0289] In step S1609, after the user plane connection between the first core network element and the terminal device is released, the first core network element replies to the second core network element with a user plane configuration response, indicating that the connection of the first core network element has been released or that relocation has been completed. This indication message may also include whether a new user plane connection to the target core network element has been established.

[0290] The following example uses NF2a as the first core network element, NF1 as the second core network element, and NF2b as the target core network element to illustrate the communication method in Figure 16 in more detail.

[0291] Referring to Figure 17, in step S1701, NF2a and the terminal device establish a user plane connection.

[0292] In step S1702, NF1 sends a user plane configuration request to NF2a, requesting the release of NF2a's connection or the migration of NF2a's connection to NF2b. This request contains information about NF2b.

[0293] In step S1703, NF2a sends a context transfer request to NF2b to migrate the context of part of the session.

[0294] In step S1704, NF2b sends a context transfer response to NF2a, which includes indication information on whether to establish a user plane connection.

[0295] In step S1705, if NF2b indicates that a user plane connection should be established, then NF2a waits for the connection release process triggered by the terminal device, or sets a timer to wait for the connection release to be triggered.

[0296] In step S1706, the process of establishing a user plane connection between NF2b and the terminal device is initiated.

[0297] In step S1707, after the connection with NF2b is established, the terminal device triggers the connection release process with NF2a.

[0298] In step S1708, the user plane connection release procedure between NF2a and the terminal device is initiated.

[0299] In step S1709, after NF2a releases its connection with the terminal device, it replies to NF1 with a user plane configuration response, indicating that the connection of NF2a has been released or that relocation has been completed. This indication message may also include whether a new connection to NF2b has been established.

[0300] It can be seen that when NF2a and NF2b interact in the context, NF2b notifies NF2a whether to establish a user plane connection. If a user plane connection is established, NF2a waits for the terminal device to trigger connection release and then notifies NF1 that the migration is complete after the connection release is finished.

[0301] During the migration process, no user plane connection is established between the terminal device and the target core network element.

[0302] Referring to Figure 18, in step S1801, a first user plane connection is established between the terminal device and the first core network element.

[0303] In step S1802, the second core network element sends a user plane configuration request to the first core network element, requesting the release of the user plane connection (first user plane connection) of the first core network element or the migration of the user plane connection of the first core network element to the target core network element (such as NF2b). The request contains information about the target core network element.

[0304] In step S1803, the first core network element sends a context transmission request to the target core network element to migrate the context of a portion of the session.

[0305] In step S1804, the target core network element sends a context transmission response to the first core network element, which includes indication information on whether to establish a user plane connection.

[0306] In step S1805, if the target core network element indicates that a user plane connection should not be established, the first core network element triggers the user plane connection release procedure.

[0307] In step S1806, the user plane connection release process between the first core network element and the terminal device is initiated.

[0308] In step S1807, after the user plane connection between the first core network element and the terminal device is released, the first core network element replies to the second core network element with a user plane configuration response, indicating that the connection of the first core network element has been released or that relocation has been completed. This indication message may also include whether a new user plane connection to the target core network element has been established.

[0309] The following example uses NF2a as the first core network element, NF1 as the second core network element, and NF2b as the target core network element to illustrate the communication method in Figure 18 in more detail.

[0310] Referring to Figure 19, in step S1901, NF2a and the terminal device establish a user plane connection.

[0311] In step S1902, NF1 sends a user plane configuration request to NF2a, requesting the release of NF2a's connection or the migration of NF2a's connection to NF2b. This request contains information about NF2b.

[0312] In step S1903, NF2a sends a context transfer request to NF2b to migrate the context of part of the session.

[0313] In step S1904, NF2b sends a context transfer response to NF2a, which includes indication information on whether to establish a user plane connection.

[0314] In step S1905, if NF2b indicates that a user plane connection should not be established, then NF2a triggers the user plane connection release procedure.

[0315] In step S1906, the user plane connection release procedure between NF2a and the terminal device is initiated.

[0316] In step S1907, after NF2a releases its connection with the terminal device, it replies to NF1 with a user plane configuration response, indicating that the connection of NF2a has been released or that relocation has been completed. This indication message may also include whether a new connection to NF2b has been established.

[0317] It can be seen that when NF2a and NF2b interact in the context, NF2b notifies NF2a whether to establish a UP face connection. If a non-UP face connection is established, NF2a directly triggers connection release and notifies NF1 that the migration is complete after the connection release is completed.

[0318] The method embodiments of this application have been described in detail above with reference to Figures 1 to 19. The apparatus embodiments of this application will be described in detail below with reference to Figures 20 to 23. It should be understood that the descriptions of the method embodiments correspond to the descriptions of the apparatus embodiments; therefore, any parts not described in detail can be referred to the preceding method embodiments.

[0319] Figure 20 is a schematic diagram of a communication device provided in an embodiment of this application. The communication device 2000 shown in Figure 20 is any of the terminal devices described above. As shown in Figure 20, the communication device 2000 includes a first receiving unit 2010 and a first determining unit 2020. The first receiving unit 2010 is used to receive a first message, the first message being used to request the establishment of a first connection between the terminal device and a first core network element; the first determining unit 2020 is used to determine whether to establish the first connection based on the maximum number of connections allowed to be established by the terminal device.

[0320] Optionally, the first message includes information for determining the connection type of the first connection, wherein the connection type indicates one of the following: the first connection is a newly established connection; or the first connection is a connection established based on a relocation trigger of a core network element.

[0321] Optionally, the first message includes explicit first indication information, which indicates the connection type.

[0322] Optionally, if the value of the first indication information is a first value, it indicates that the first connection is a newly established connection; if the value of the first indication information is a second value, it indicates that the first connection is a connection established based on the relocation trigger. Alternatively, if the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection is a connection established based on the relocation trigger.

[0323] Optionally, the first message includes implicit second indication information, which is used to determine the connection type.

[0324] Optionally, the second indication information includes information about the source core network element associated with the relocation and / or information about the user plane address of the terminal device and the source core network element.

[0325] Optionally, the first determining unit is configured to: the terminal device determine whether to establish the first connection based on the maximum number of connections and / or the connection type.

[0326] Optionally, the first determining unit is configured to: establish the first connection if the number of connections established by the terminal device does not exceed the maximum number of connections, or if the first connection is a connection established based on relocation triggering; and / or refuse to establish the first connection if the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection.

[0327] Optionally, the communication device further includes: a first sending unit, configured to send a first parameter to the first core network element if the terminal device refuses to establish the first connection, wherein the first parameter is used to indicate that the reason why the terminal device refuses to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

[0328] Optionally, the communication device further includes: a release unit, configured to release a second connection if the first connection is a connection established based on the relocation trigger, wherein the second connection is a connection between the terminal device and the source core network element associated with the relocation.

[0329] Figure 21 is a schematic diagram of a communication device provided in an embodiment of this application. The communication device 2100 shown in Figure 21 is any of the second core network elements described above. As shown in Figure 21, the communication device 2100 includes a second receiving unit 2110 and a second determining unit 2120. The second receiving unit 2110 is used to receive a second message sent by a first core network element, the second message being used to request the establishment of a first connection between the terminal device and the first core network element; the second determining unit 2120 is used to determine whether the terminal device allows the establishment of the first connection based on the maximum number of connections allowed to be established by the terminal device.

[0330] Optionally, the second message includes information for determining the connection type of the first connection, the connection type indicating one of the following: the first connection is a newly established connection; the first connection is a connection established based on the relocation trigger of a core network element.

[0331] Optionally, the second message includes explicit first indication information, which indicates the connection type.

[0332] Optionally, if the value of the first indication information is a first value, it indicates that the first connection is a newly established connection; if the value of the first indication information is a second value, it indicates that the first connection is a connection established based on the relocation trigger. Alternatively, if the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection is a connection established based on the relocation trigger.

[0333] Optionally, the second message includes implicit second indication information used to determine the connection type.

[0334] Optionally, the second indication information includes information about the source core network element associated with the relocation.

[0335] Optionally, the second determining unit is configured to: determine whether the terminal device allows the establishment of the first connection based on the maximum number of connections and / or the connection type.

[0336] Optionally, the second determining unit is configured to: if the number of connections established by the terminal device does not exceed the maximum number of connections, or the first connection is a connection established based on relocation triggering, then the second core network element determines that the terminal device is allowed to establish the first connection; and / or if the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection, then the second core network element determines that the terminal device is not allowed to establish the first connection.

[0337] Optionally, the communication device further includes: a second sending unit, configured to send a first parameter to the first core network element if the second core network element determines that the terminal device is not allowed to establish the first connection, wherein the first parameter is used to indicate that the reason for refusing to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

[0338] Optionally, the communication device further includes a recording unit for recording connections in the relocation state among the connections established by the terminal device.

[0339] Optionally, the connection in the relocation state among the connections established by the terminal device includes the first connection, and the communication device further includes: a third determining unit, configured to determine that the migration process of the first connection has been completed if the second core network element receives a third message sent by the first core network element and / or the first timer times out; wherein, the third message is used to indicate that the first connection has been released or the migration process of the first connection has been completed, and the first timer is a timer associated with the migration process.

[0340] Optionally, the connection established by the terminal device includes a second connection, and the second connection is in a relocation state. The target core network element of the relocation process associated with the second connection is a third core network element.

[0341] The communication device further includes a fourth determining unit, configured to determine that the terminal device allows the establishment of a connection if the second core network element receives a message from the third core network element requesting the establishment of a connection.

[0342] Figure 22 is a schematic diagram of a communication device provided in an embodiment of this application. The communication device 2200 shown in Figure 22 is any of the first core network elements described above. As shown in Figure 22, the communication device 2200 includes a third sending unit 2210 and an establishment unit 2220. The third sending unit 2210 is used to send a second message to a second core network element, the second message being used to request the establishment of a first connection between the terminal device and the first core network element; the establishment unit 2220 is used to establish the first connection with the terminal device if the number of connections established by the terminal device does not exceed the maximum number of connections allowed to be established by the terminal device.

[0343] Optionally, the second message includes information for determining the connection type of the first connection, the connection type indicating one of the following: the first connection is a newly established connection; the first connection is a connection established based on the relocation trigger of a core network element.

[0344] Optionally, the second message includes explicit first indication information, which indicates the connection type.

[0345] Optionally, if the value of the first indication information is a first value, it indicates that the first connection is a newly established connection; if the value of the first indication information is a second value, it indicates that the first connection is a connection established based on the relocation trigger. Alternatively, if the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection is a connection established based on the relocation trigger.

[0346] Optionally, the second message includes implicit second indication information used to determine the connection type.

[0347] Optionally, the second indication information includes information about the source core network element associated with the relocation.

[0348] Optionally, the communication device further includes: a third receiving unit, configured to receive a first parameter sent by the terminal device or the second core network element when the terminal device or the second core network element refuses to establish the first connection, wherein the first parameter is used to indicate that the reason for refusing to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

[0349] Optionally, the communication device further includes: a fourth sending unit, configured to send a third message to the second core network element, the third message being used by the second core network element to determine the relocation status of the first connection.

[0350] Optionally, the third information is used to indicate one or more of the following: the first connection has been released; the migration process of the first connection has been completed; the target core network element associated with the relocation has established or not established a new connection with the terminal device.

[0351] Figure 23 is a schematic structural diagram of a communication device according to an embodiment of this application. The dashed lines in Figure 23 indicate that the unit or module is optional. This device 2300 can be used to implement the methods described in the above method embodiments. Device 2300 can be a chip, a terminal device, or a network device.

[0352] Apparatus 2300 may include one or more processors 2310. The processor 2310 may support apparatus 2300 in implementing the methods described in the preceding method embodiments. The processor 2310 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0353] The apparatus 2300 may further include one or more memories 2320. The memories 2320 store a program that can be executed by the processor 2310, causing the processor 2310 to perform the methods described in the preceding method embodiments. The memories 2320 may be independent of the processor 2310 or integrated within the processor 2310.

[0354] The device 2300 may also include a transceiver 2330. The processor 2310 can communicate with other devices or chips via the transceiver 2330. For example, the processor 2310 can send and receive data with other devices or chips via the transceiver 2330.

[0355] This application also provides a computer-readable storage medium for storing a program. This computer-readable storage medium can be applied to a terminal or network device provided in this application, and the program causes a computer to execute the methods performed by the terminal device or network device in various embodiments of this application.

[0356] This application also provides a computer program product. The computer program product includes a program. This computer program product can be applied to a terminal or network device provided in this application embodiment, and the program causes a computer to execute the methods performed by the terminal device or network device in various embodiments of this application.

[0357] This application also provides a computer program. This computer program can be applied to the terminal device or network device provided in this application, and the computer program causes the computer to execute the methods performed by the terminal device or network device in various embodiments of this application.

[0358] It should be understood that the terminology used in this application is only for explaining specific embodiments of this application and is not intended to limit this application. The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0359] In the embodiments of this application, the term "instruction" can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

[0360] In the embodiments of this application, "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean that B is determined solely based on A; B can also be determined based on A and / or other information.

[0361] In the embodiments of this application, the term "correspondence" can indicate a direct or indirect correspondence between two things, or an association between two things, or a relationship such as instruction and being instructed, configuration and being configured.

[0362] In this application embodiment, "predefined" or "preconfigured" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device (e.g., including terminal devices and network devices). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

[0363] In this application embodiment, the "protocol" may refer to a standard protocol in the field of communication, such as the LTE protocol, the NR protocol, and related protocols applied to future communication systems. This application does not limit this.

[0364] In the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0365] In the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0366] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0367] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0368] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0369] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can read or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs, DVDs) or semiconductor media (e.g., solid-state disks, SSDs), etc.

[0370] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, include: The terminal device receives a first message, which is used to request the establishment of a first connection between the terminal device and the first core network element. The terminal device determines whether to establish the first connection based on the maximum number of connections allowed to be established by the terminal device.

2. The method according to claim 1, characterized in that, The first message contains information for determining the connection type of the first connection, the connection type indicating one of the following: The first connection is a newly established connection; The first connection is a connection established based on the relocation trigger of the core network element.

3. The method according to claim 2, characterized in that, The first message contains explicit first indication information, which indicates the connection type.

4. The method according to claim 3, characterized in that: If the first indication information takes a first value, it indicates that the first connection is a newly established connection; if the first indication information takes a second value, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a connection established based on the relocation trigger; if the connection request does not contain the first indication information, it indicates that the first connection is a newly established connection.

5. The method according to claim 2, characterized in that, The first message contains implicit second indication information, which is used to determine the connection type.

6. The method according to claim 5, characterized in that, The second indication information includes information about the source core network element associated with the relocation and / or information about the user plane address of the terminal device and the source core network element.

7. The method according to any one of claims 2 to 6, characterized in that, The terminal device determines whether to establish the first connection based on the maximum number of connections allowed to be established by the terminal device, including: The terminal device determines whether to establish the first connection based on the maximum number of connections and / or the connection type.

8. The method according to claim 7, characterized in that, The terminal device determines whether to establish the first connection based on the maximum number of connections and / or the connection type, including: If the number of connections established by the terminal device does not exceed the maximum number of connections, or if the first connection is a connection established based on a relocation trigger, then the terminal device establishes the first connection; and / or If the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection, then the terminal device refuses to establish the first connection.

9. The method according to claim 8, characterized in that, The method further includes: If the terminal device refuses to establish the first connection, the terminal device sends a first parameter to the first core network element. The first parameter indicates that the reason for the terminal device refusing to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

10. The method according to any one of claims 2 to 9, characterized in that, The method further includes: If the first connection is a connection established based on the relocation trigger, then the terminal device releases the second connection, which is a connection between the terminal device and the source core network element associated with the relocation.

11. A communication method, characterized in that, include: The second core network element receives a second message sent by the first core network element, the second message being used to request the establishment of a first connection between the terminal device and the first core network element; The second core network element determines whether the terminal device allows the establishment of the first connection based on the maximum number of connections that the terminal device is allowed to establish.

12. The method according to claim 11, characterized in that, The second message contains information for determining the connection type of the first connection, the connection type indicating one of the following: The first connection is a newly established connection; The first connection is a connection established based on the relocation trigger of the core network element.

13. The method according to claim 12, characterized in that, The second message contains explicit first indication information, which indicates the connection type.

14. The method according to claim 13, characterized in that: If the first indication information takes a first value, it indicates that the first connection is a newly established connection; if the first indication information takes a second value, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a connection established based on the relocation trigger; if the connection request does not contain the first indication information, it indicates that the first connection is a newly established connection.

15. The method according to claim 12, characterized in that, The second message contains implicit second indication information used to determine the connection type.

16. The method according to claim 15, characterized in that, The second indication information includes information about the source core network element associated with the relocation.

17. The method according to any one of claims 12 to 16, characterized in that, The second core network element determines whether the terminal device allows the establishment of the first connection based on the maximum number of connections allowed to be established by the terminal device, including: The second core network element determines whether the terminal device allows the establishment of the first connection based on the maximum number of connections and / or the connection type.

18. The method according to claim 17, characterized in that, The second core network element determines whether the terminal device allows the establishment of the first connection based on the maximum number of connections and / or the connection type, including: If the number of connections established by the terminal device does not exceed the maximum number of connections, or if the first connection is a connection established based on a relocation trigger, then the second core network element determines that the terminal device is allowed to establish the first connection; and / or If the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection, then the second core network element determines that the terminal device is not allowed to establish the first connection.

19. The method according to claim 18, characterized in that, The method further includes: If the second core network element determines that the terminal device does not allow the establishment of the first connection, the second core network element sends a first parameter to the first core network element. The first parameter is used to indicate the reason for refusing to establish the first connection: the number of connections established by the terminal device exceeds the maximum number of connections.

20. The method according to any one of claims 11 to 19, characterized in that, The method further includes: The second core network element records connections that are in a relocation state among the connections established by the terminal device.

21. The method according to claim 20, characterized in that, The connection in the relocation state among the connections established by the terminal device includes the first connection, and the method further includes: If the second core network element receives a third message sent by the first core network element and / or the first timer times out, the second core network element determines that the migration process of the first connection has been completed. The third message indicates that the first connection has been released or the migration process of the first connection has been completed, and the first timer is a timer associated with the migration process.

22. The method according to claim 20 or 21, characterized in that, The connection established by the terminal device includes a second connection, and the second connection is in a relocation state. The target core network element of the relocation process associated with the second connection is a third core network element. The method further includes: If the second core network element receives a message from the third core network element requesting the establishment of a connection, the second core network element determines that the terminal device allows the establishment of a connection.

23. A communication method, characterized in that, include: The first core network element sends a second message to the second core network element, the second message being used to request the establishment of a first connection between the terminal device and the first core network element; If the number of connections established by the terminal device does not exceed the maximum number of connections allowed to be established by the terminal device, the first core network element establishes the first connection with the terminal device.

24. The method according to claim 23, characterized in that, The second message contains information for determining the connection type of the first connection, the connection type indicating one of the following: The first connection is a newly established connection; The first connection is a connection established based on the relocation trigger of the core network element.

25. The method according to claim 24, characterized in that, The second message contains explicit first indication information, which indicates the connection type.

26. The method according to claim 25, characterized in that: If the first indication information takes a first value, it indicates that the first connection is a newly established connection; if the first indication information takes a second value, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a connection established based on the relocation trigger; if the connection request does not contain the first indication information, it indicates that the first connection is a newly established connection.

27. The method according to claim 24, characterized in that, The second message contains implicit second indication information used to determine the connection type.

28. The method according to claim 27, characterized in that, The second indication information includes information about the source core network element associated with the relocation.

29. The method according to any one of claims 24 to 28, characterized in that, The method further includes: If the terminal device or the second core network element refuses to establish the first connection, the first core network element receives a first parameter sent by the terminal device or the second core network element. The first parameter is used to indicate that the reason for refusing to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

30. The method according to any one of claims 23 to 29, characterized in that, The method further includes: The first core network element sends a third message to the second core network element, the third message being used by the second core network element to determine the relocation status of the first connection.

31. The method according to claim 30, characterized in that, The third information is used to indicate one or more of the following: The first connection has been released; The migration process for the first connection has been completed; The target core network element associated with the relocation may or may not establish a new connection with the terminal device.

32. A communication device, characterized in that, The communication device is a terminal device, and the communication device includes: The first receiving unit is configured to receive a first message, the first message being used to request the establishment of a first connection between the terminal device and the first core network element; The first determining unit is configured to determine whether to establish the first connection based on the maximum number of connections allowed to be established by the terminal device.

33. The communication device according to claim 32, characterized in that, The first message contains information for determining the connection type of the first connection, the connection type indicating one of the following: The first connection is a newly established connection; The first connection is a connection established based on the relocation trigger of the core network element.

34. The communication device according to claim 33, characterized in that, The first message contains explicit first indication information, which indicates the connection type.

35. The communication device according to claim 34, characterized in that: If the first indication information takes a first value, it indicates that the first connection is a newly established connection; if the first indication information takes a second value, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a connection established based on the relocation trigger; if the connection request does not contain the first indication information, it indicates that the first connection is a newly established connection.

36. The communication device according to claim 33, characterized in that, The first message contains implicit second indication information, which is used to determine the connection type.

37. The communication device according to claim 36, characterized in that, The second indication information includes information about the source core network element associated with the relocation and / or information about the user plane address of the terminal device and the source core network element.

38. The communication device according to any one of claims 33 to 37, characterized in that, The first determining unit is used for: The terminal device determines whether to establish the first connection based on the maximum number of connections and / or the connection type.

39. The communication device according to claim 38, characterized in that, The first determining unit is used for: If the number of connections established by the terminal device does not exceed the maximum number of connections, or if the first connection is a connection established based on a relocation trigger, then the terminal device establishes the first connection; and / or If the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection, then the terminal device refuses to establish the first connection.

40. The communication device according to claim 39, characterized in that, The communication device also includes: The first sending unit is configured to send a first parameter to the first core network element if the terminal device refuses to establish the first connection. The first parameter is used to indicate that the reason why the terminal device refuses to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

41. The communication device according to any one of claims 33 to 40, characterized in that, The communication device also includes: A release unit is configured to release a second connection if the first connection is a connection established based on the relocation trigger, wherein the second connection is a connection between the terminal device and the source core network element associated with the relocation.

42. A communication device, characterized in that, The communication device is a second core network element, and the communication device includes: The second receiving unit is used to receive a second message sent by the first core network element, the second message being used to request the establishment of a first connection between the terminal device and the first core network element; The second determining unit is used to determine whether the terminal device allows the establishment of the first connection based on the maximum number of connections that the terminal device is allowed to establish.

43. The communication device according to claim 32, characterized in that, The second message contains information for determining the connection type of the first connection, the connection type indicating one of the following: The first connection is a newly established connection; The first connection is a connection established based on the relocation trigger of the core network element.

44. The communication device according to claim 43, characterized in that, The second message contains explicit first indication information, which indicates the connection type.

45. The communication device according to claim 44, characterized in that: If the first indication information takes a first value, it indicates that the first connection is a newly established connection; if the first indication information takes a second value, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a connection established based on the relocation trigger; if the connection request does not contain the first indication information, it indicates that the first connection is a newly established connection.

46. ​​The communication device according to claim 43, characterized in that, The second message contains implicit second indication information used to determine the connection type.

47. The communication device according to claim 46, characterized in that, The second indication information includes information about the source core network element associated with the relocation.

48. The communication device according to any one of claims 43 to 47, characterized in that, The second determining unit is used for: Whether the terminal device allows the establishment of the first connection is determined based on the maximum number of connections and / or the connection type.

49. The communication device according to claim 48, characterized in that, The second determining unit is used for: If the number of connections established by the terminal device does not exceed the maximum number of connections, or if the first connection is a connection established based on relocation triggering, then the second core network element determines that the terminal device is allowed to establish the first connection. and / or If the number of connections established by the terminal device exceeds the maximum number of connections, and the first connection is a newly established connection, then the second core network element determines that the terminal device is not allowed to establish the first connection.

50. The communication device according to claim 49, characterized in that, The communication device also includes: The second sending unit is configured to send a first parameter to the first core network element if the second core network element determines that the terminal device is not allowed to establish the first connection. The first parameter is used to indicate that the reason for refusing to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

51. The communication device according to any one of claims 42 to 50, characterized in that, The communication device also includes: A recording unit is used to record connections in the relocation state among the connections established by the terminal device.

52. The communication device according to claim 51, characterized in that, The connection in the relocation state among the connections established by the terminal device includes the first connection, and the communication device further includes: The third determining unit is used to determine that the migration process of the first connection has been completed if the second core network element receives a third message sent by the first core network element and / or the first timer times out. The third message indicates that the first connection has been released or the migration process of the first connection has been completed, and the first timer is a timer associated with the migration process.

53. The communication device according to claim 51 or 52, characterized in that, The connection established by the terminal device includes a second connection, and the second connection is in a relocation state. The target core network element of the relocation process associated with the second connection is a third core network element. The communication device also includes: The fourth determining unit is configured to determine that the terminal device allows the connection to be established if the second core network element receives a message from the third core network element requesting the establishment of a connection.

54. A communication device, characterized in that, The communication device is a first core network element, and the communication device includes: The third sending unit is used to send a second message to the second core network element, the second message being used to request the establishment of a first connection between the terminal device and the first core network element; The connection establishment unit is configured to establish the first connection with the terminal device if the number of connections established by the terminal device does not exceed the maximum number of connections allowed to be established by the terminal device.

55. The communication device according to claim 54, characterized in that, The second message contains information for determining the connection type of the first connection, the connection type indicating one of the following: The first connection is a newly established connection; The first connection is a connection established based on the relocation trigger of the core network element.

56. The communication device according to claim 55, characterized in that, The second message contains explicit first indication information, which indicates the connection type.

57. The communication device according to claim 56, characterized in that: If the first indication information takes a first value, it indicates that the first connection is a newly established connection; if the first indication information takes a second value, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a newly established connection; if the connection request does not contain the first indication information, it indicates that the first connection was established based on the relocation trigger; or... If the connection request contains the first indication information, it indicates that the first connection is a connection established based on the relocation trigger; if the connection request does not contain the first indication information, it indicates that the first connection is a newly established connection.

58. The communication device according to claim 55, characterized in that, The second message contains implicit second indication information used to determine the connection type.

59. The communication device according to claim 58, characterized in that, The second indication information includes information about the source core network element associated with the relocation.

60. The communication device according to any one of claims 55 to 59, characterized in that, The communication device also includes: The third receiving unit is configured to receive a first parameter sent by the terminal device or the second core network element when the terminal device or the second core network element refuses to establish the first connection. The first parameter is used to indicate that the reason for refusing to establish the first connection is that the number of connections established by the terminal device exceeds the maximum number of connections.

61. The communication device according to any one of claims 54 to 60, characterized in that, The communication device also includes: The fourth sending unit is used to send a third message to the second core network element, the third message being used by the second core network element to determine the relocation status of the first connection.

62. The communication device according to claim 61, characterized in that, The third information is used to indicate one or more of the following: The first connection has been released; The migration process for the first connection has been completed; The target core network element associated with the relocation may or may not establish a new connection with the terminal device.

63. A communication device, characterized in that, The device includes a transceiver, a memory, and a processor. The memory stores a program, and the processor invokes the program in the memory and controls the transceiver to receive or transmit signals so that the communication device performs the method as described in any one of claims 1 to 31.

64. An apparatus, characterized in that, Includes a processor for calling a program from memory to cause the device to perform the method as described in any one of claims 1 to 31.

65. A chip, characterized in that, Includes a processor for calling a program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1 to 31.

66. A computer-readable storage medium, characterized in that, It contains a program that causes a computer to perform the method as described in any one of claims 1 to 31.

67. A computer program product, characterized in that, Includes a program that causes a computer to perform the method as described in any one of claims 1 to 31.

68. A computer program, characterized in that, The computer program causes the computer to perform the method as described in any one of claims 1 to 31.

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