Paging method and apparatus

Abstract

The present application relates to the technical field of communications, and provides a paging method and apparatus. The method comprises: an AMF network element receives a first message from an SMF network element, the first message comprising an identifier of a first session of a first terminal; and the AMF network element sends a first paging message to a first access network device corresponding to a first RAT type associated with the first session. Therefore, paging of the first terminal is realized, and thus recovery of the communication connection of the first session is realized.

Description

Paging method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on November 17, 2023, with application number 202311549447.X and application name “A Paging Method and Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a paging method and device. Background Art

[0004] With the development of communication technology, future terminals, such as mobile phones, may have dual connectivity. A terminal equipped with a subscriber identity module (SIM) card can simultaneously connect to two radio access networks (RANs) in dual connectivity mode, maintaining radio resource control (RRC) connections with both RANs and transmitting the same or different data through the two RANs. When a terminal accesses the network through two RANs using different radio access technologies (RATs), how to page the terminal if it is idle is a research topic.

[0005] Summary of the Invention

[0006] The present application provides a paging method and apparatus to implement paging of a terminal.

[0007] In a first aspect, a paging method is provided. The method is applied to an access and mobility management function network element. The execution subject of the method may be the access and mobility management network element, or a module (e.g., a chip or circuit) in the access and mobility management network element, comprising: receiving a first message from a session management function network element, the first message including an identifier of a first session of a first terminal, the first session being associated with a first radio access technology type, the first terminal being registered with the access and mobility management function network element via an access network device of the first radio access technology type and an access network device of a second radio access technology type; and sending a first paging message to a first access network device corresponding to the first radio access technology type, the first paging message including a first identifier of the first terminal. Optionally, the first access network device may be one access network device, or multiple access network devices, without limitation.

[0008] Through the above method, when the first terminal adopts a dual 3rd generation partnership project (3GPP) access method to access two access network devices, and the two access network devices have different radio access technology types: when the access and mobility management function network element receives a notification of the arrival of downlink data of a certain session, the access and mobility management function network element can determine a certain radio access technology type based on the association between the session and the radio access technology type. The access and mobility management function network element can page the first terminal through the access network device corresponding to the radio access technology type, thereby achieving paging of the first terminal and further restoring the communication connection of the session.

[0009] In one possible design, the first access network device is in a first registration area corresponding to the first wireless access technology type.

[0010] In one possible design, the method further includes: receiving a first registration request from the first terminal, the first registration request being received by an access network device of the first radio access technology type; and sending a first registration response to the first terminal, the first registration response including a first registration area corresponding to the first radio access technology type. Furthermore, the method further includes: storing an association between the first radio access technology type and the first registration area.

[0011] In one possible design, the method further includes: receiving a second registration request from the first terminal, the second registration request being received by an access network device of the second radio access technology type; and sending a second registration response to the first terminal, the second registration response including a second registration area corresponding to the second radio access technology type. Furthermore, the method further includes: storing an association between the second radio access technology type and the second registration area.

[0012] Through the above method, when the first terminal uses a dual 3GPP access mode to access two access network devices, and the two access network devices have different radio access technology types: when the access and mobility management function network element receives a notification of the arrival of downlink data of a certain session, the access and mobility management function network element can determine a certain radio access technology type based on the association between the session and the radio access technology type. Furthermore, the access and mobility management function network element determines the registration area corresponding to the radio access technology type based on the maintained correspondence between different radio access technology types and registration areas. The access and mobility management function network element pages the first terminal through the access network device corresponding to the registration area, thereby achieving paging of the first terminal and further restoring the communication connection of the session. By allocating different registration areas to different radio access technology types, it is beneficial for the network to perform mobility management of different radio access technology types on the terminal, thereby improving the flexibility of mobility management.

[0013] In one possible design, the method further includes: determining a first identifier of the first terminal based on the first wireless access technology type.

[0014] In one possible design, the method further includes: receiving a third registration request from the first terminal, the third registration request being received by an access network device of the first wireless access technology type; and sending a third registration response to the first terminal, the third registration response including a second identifier of the first terminal corresponding to the first wireless access technology type, the second identifier including the first identifier. Furthermore, the method further includes: storing an association between the second identifier and the first wireless access technology type, or storing an association between the first identifier and the first wireless access technology type.

[0015] In one possible design, the method further includes: receiving a fourth registration request from the first terminal, the fourth registration request being received by an access network device of the second radio access technology type; and sending a fourth registration response to the first terminal, the fourth registration response including a third identifier of the first terminal corresponding to the second radio access technology type, the third identifier including a fourth identifier of the first terminal. Furthermore, the method further includes: storing an association between the third identifier and the second radio access technology type, or storing an association between the fourth identifier and the second radio access technology type.

[0016] Through the above method, since the identifier of the first terminal is associated with the wireless access technology type, when paging the first terminal, it is sufficient to carry the identifier of the first terminal corresponding to the wireless access technology type in the paging message without the need for paging enhancement, for example, avoiding carrying indication information of the wireless access technology type in the paging message, etc., thereby saving the overhead of the paging message.

[0017] In one possible design, the connection state of the first terminal corresponding to the first wireless access technology type is an idle state.

[0018] In one possible design, the method further includes: determining the first radio access technology type associated with the first session based on an association relationship between the session and the radio access technology type.

[0019] In one possible design, the first paging message also includes indication information of the first radio access technology type.

[0020] In one possible design, the first session is also associated with a second radio access technology type, and the method further includes: determining the first radio access technology type from the first radio access technology type and the second radio access technology type. Optionally, the first paging message further includes dual connection indication information, and the dual connection includes connections corresponding to the first radio access technology type and the second radio access technology type, or the first paging message further includes the first radio access technology type and the second radio access technology type. Optionally, the dual connection indication information is used to instruct the first terminal to resume or establish a connection with an access network device of the first RAT type and an access network device of the second RAT type. For example, when the first terminal obtains the dual connection indication information in the paging message, the first terminal resumes or establishes a connection with the access network device of the first RAT type and the access network device of the second RAT type, and the connection may refer to an RRC connection. Optionally, the dual connection indication information is used to instruct the first terminal to resume a session established between the access network device of the first RAT type and the access network device of the second RAT type. For example, when the first terminal obtains the indication information of dual connection in the paging message, the first terminal restores or establishes the connection with the access network device of the first RAT type and the access network device of the second RAT type, and requests to restore the session established between the access network device of the first RAT type and the access network device of the second RAT type.

[0021] Through the above method, when a session is established through access network devices of two radio access technology types, one of the two radio access technology types can be selected to page the first terminal. For example, selecting a radio access technology type with good coverage or low latency is beneficial for improving paging efficiency. Upon receiving the paging message, the first terminal can restore the communication connection of the first session across both radio access technology types based on the information carried in the paging message (e.g., dual connectivity indication information).

[0022] The second aspect is a contralateral method of the first aspect. The beneficial effects can be found in the description of the first aspect. A paging method is provided, which is applied to a first terminal. The execution subject of the method is the first terminal, or a module in the first terminal (for example, a chip or circuit, etc.), including: receiving a second paging message, the second paging message is received through a first access network device corresponding to a first wireless access technology type, the second paging message includes a first identifier of the first terminal, the first terminal registers to an access and mobility management function network element through an access network device of the first wireless access technology type and an access network device of the second wireless access technology type; determining the first wireless access technology type according to the second paging message or the first identifier; sending a second message to the access and mobility management function network element through the second access network device corresponding to the first wireless access technology type, the second message including an identifier of a first session associated with the first wireless access technology type, and the second message is used to request restoration of the communication connection of the first session.

[0023] In one possible design, the first access network device is in a first registration area corresponding to the first wireless access technology type.

[0024] In one possible design, the method further includes: sending a first registration request to the access and mobility management function network element, the first registration request being sent via an access network device of the first radio access technology type; and receiving a first registration response from the access and mobility management function network element, the first registration response including a first registration area corresponding to the first radio access technology type. Furthermore, the method further includes: storing an association between the first radio access technology type and the first registration area.

[0025] In one possible design, the method further includes: sending a second registration request to the access and mobility management function network element, the second registration request being sent by an access network device of the second radio access technology type; and receiving a second registration response from the access and mobility management function network element, the second registration response including a second registration area of ​​the second radio access technology type. Furthermore, the method further includes: storing an association between the second radio access technology type and the second registration area.

[0026] In one possible design, determining the first wireless access technology type based on the second paging message includes: determining the first wireless access technology type based on the indication information of the first wireless access technology type included in the second paging message; or determining the first wireless access technology type based on the wireless resources for receiving the second paging message.

[0027] In one possible design, the method further includes: sending a third registration request to the access and mobility management function network element, the third registration request being sent via an access network device of the first radio access technology type; and receiving a third registration response from the access and mobility management function network element, the third registration response including a second identifier of the first terminal of the first radio access technology type, the second identifier including the first identifier. Furthermore, the method further includes: storing an association between the second identifier and the first radio access technology type, or storing an association between the first identifier and the first radio access technology type.

[0028] In one possible design, the method further includes: sending a fourth registration request to the access and mobility management function network element, the fourth registration request being sent via an access network device of the second radio access technology type; and receiving a fourth registration response from the access and mobility management function network element, the fourth registration response including a third identifier of the first terminal of the second radio access technology type, the third identifier including a fourth identifier of the first terminal. Furthermore, the method further includes: storing an association between the third identifier and the second radio access technology type, or storing an association between the fourth identifier and the second radio access technology type.

[0029] In one possible design, the method further includes: determining a first cell based on the first wireless access technology type, where the first cell is a cell provided by the second access network device.

[0030] In one possible design, the connection state of the first terminal corresponding to the first wireless access technology type is an idle state.

[0031] The third aspect is a contralateral method of the first aspect. For beneficial effects, please refer to the description of the first aspect. A paging method is provided, which is applied to a first terminal. The execution subject of the method is the first terminal, or a module (such as a chip or circuit, etc.) applied to the first terminal, including: receiving a third paging message, the third paging message is received through a first access network device corresponding to a first wireless access technology type, the third paging message includes a first identifier of the first terminal, and the first terminal registers to an access and mobility management function network element through an access network device of the first wireless access technology type and an access network device of a second wireless access technology type; according to the third paging message, determining the first wireless access technology type and the second wireless access technology type; sending a third message to the access and mobility management function network element through a third access network device corresponding to the first wireless access technology type and a fourth access network device corresponding to the second wireless access technology type, the third message including an identifier of a first session associated with the first wireless access technology type and the second wireless access technology type, and the third message is used to request restoration of the communication connection of the first session.

[0032] In one possible design, the third paging message further includes dual-connection indication information, where the dual-connection includes connections corresponding to the first radio access technology type and the second radio access technology type, or the third paging message further includes indication information of the first radio access technology type and the second radio access technology type. Optionally, the dual-connection indication information is used to instruct the first terminal to resume or establish a connection with an access network device of the first RAT type and an access network device of the second RAT type. For example, when the first terminal obtains the dual-connection indication information in the paging message, the first terminal resumes or establishes a connection with the access network device of the first RAT type and the access network device of the second RAT type, where the connection may be an RRC connection. Optionally, the dual-connection indication information is used to instruct the first terminal to resume a session established with the access network device of the first RAT type and the access network device of the second RAT type. For example, when the first terminal obtains the dual-connection indication information in the paging message, the first terminal resumes or establishes a connection with the access network device of the first RAT type and the access network device of the second RAT type, and requests to resume the session established with the access network device of the first RAT type and the access network device of the second RAT type.

[0033] In one possible design, the method also includes: determining a second cell based on the first wireless access technology type, the second cell being a cell provided by a third access network device corresponding to the first wireless access technology type; and determining a third cell based on the second wireless access technology type, the third cell being a cell provided by a fourth access network device corresponding to the second wireless access technology type.

[0034] In one possible design, the connection state of the first terminal corresponding to the first wireless access technology type is an idle state.

[0035] In a fourth aspect, a paging method is provided, which is applied to an access and mobility management function network element. The execution subject of the method can be the access and mobility management function network element, or a module in the access and mobility management function network element (for example, a chip or circuit, etc.), including: receiving a fourth message from a session management function network element, the fourth message including an identifier of a second session of a second terminal, the second session being associated with a third radio access technology type, and the second terminal registering with the access and mobility management function network element through an access network device of the third radio access technology type and an access network device of a fourth radio access technology type; sending a fourth paging message to a target access network device corresponding to a target radio access technology type, the fourth paging message including an identifier of the second terminal, the target radio access technology type being determined by the second terminal or the access and mobility management function network element, and the target radio access technology type being the third radio access technology type or the fourth radio access technology type.

[0036] Through the above method, the access and mobility management function network element negotiates with the second terminal on the radio access technology type used to paging the second terminal, and the second terminal listens to the paging message under the negotiated radio access technology type, thereby saving the terminal's listening energy consumption. "Listening" can be understood as receiving. For example, the access and mobility management function network element negotiates with the second terminal to page the second terminal under the third radio access technology type, then the access and mobility management function network element sends a fourth paging message to the access network device of the third radio access technology type, the access network device of the third radio access technology type sends a fifth paging message to the second terminal, and the second terminal listens to the paging message under the access network device of the third radio access technology type. By listening to the paging message only under a specific radio access technology type, the terminal's listening energy consumption is saved.

[0037] In one possible design, the target access network device is in the registration area corresponding to the target wireless access technology type.

[0038] In one possible design, the target radio access technology type is the third radio access technology type, and the method further includes: receiving a fifth registration request from the second terminal, the fifth registration request being received by an access network device of the third radio access technology type; and sending a fifth registration response to the second terminal, the fifth registration response including a third registration area associated with the third radio access technology type. Furthermore, the method further includes: storing an association between the third radio access technology type and the third registration area.

[0039] In one possible design, the target radio access technology type is the fourth radio access technology type, and the method further includes: receiving a sixth registration request from the second terminal, the sixth registration request being received by an access network device of the fourth radio access technology type; and sending a sixth registration response to the second terminal, the sixth registration response including a fourth registration area associated with the fourth radio access technology type. Furthermore, the method further includes: storing an association between the fourth radio access technology type and the fourth registration area.

[0040] In one possible design, the target wireless access technology type is determined by the second terminal, and the method further includes: receiving a fifth message from the second terminal, the fifth message including indication information of the target wireless access technology type.

[0041] In one possible design, the target wireless access technology type is determined by the access and mobility management function network element, and the method also includes: sending a sixth message to the second terminal, the sixth message including indication information of the target wireless access technology type.

[0042] In one possible design, the target wireless access technology type is the fourth wireless access technology type, and the fourth paging message also includes indication information of the third wireless access technology type.

[0043] In one possible design, the state of the second terminal corresponding to the third wireless access technology type is an idle state.

[0044] The fifth aspect is a method on the opposite side of the fourth aspect. The beneficial effects can be found in the description of the fourth aspect. A paging method is provided, which is applied to a second terminal. The execution subject of the method is the second terminal, or a module (for example, a chip or circuit, etc.) applied to the second terminal, including: receiving a fifth paging message, the fifth paging message is received by the target access network device corresponding to the target wireless access technology type, the fifth paging message includes the identifier of the second terminal, the target wireless access technology type is determined by the second terminal or the access and mobility management function network element, and the second terminal receives the paging message through the access network device of the third wireless access technology type and the fourth wireless access technology type. type of access network device registers with the access and mobility management function network element, and the target wireless access technology type is the third wireless access technology type, or the fourth wireless access technology type; when the target wireless access technology type is the fourth wireless access technology type, the fifth paging message also includes indication information of the third wireless access technology type; through the access network device corresponding to the third wireless access technology type, a seventh message is sent to the access and mobility management function network element, the seventh message includes the identifier of the second session corresponding to the third wireless access technology type, and the seventh message is used to request to restore the communication connection of the second session.

[0045] In one possible design, the receiving of the fifth paging message includes: receiving the fifth paging message according to the target radio access technology type. For example, different radio access technology types have different radio resources for transmitting paging messages. The third radio access technology type corresponds to the third radio resource, and the fourth radio access technology type corresponds to the fourth radio resource. When the target radio access technology type negotiated between the access and mobility function management network element and the second terminal is the third radio access technology type, the second terminal receives the fifth paging message on the third radio resource. Alternatively, when the target radio access technology type negotiated between the access and mobility function management network element and the second terminal is the fourth radio access technology type, the second terminal receives the fifth paging message on the fourth radio resource.

[0046] In one possible design, the target access network device is in the registration area corresponding to the target wireless access technology type.

[0047] In one possible design, the target radio access technology type is the third radio access technology type, and the method further includes: sending a fifth registration request to the access and mobility management function network element, the fifth registration request being sent by an access network device of the third radio access technology type; and receiving a fifth registration response from the access and mobility management function network element, the fifth registration response including a third registration area associated with the third radio access technology type. Furthermore, the method further includes: storing an association between the third radio access technology type and the third registration area.

[0048] In one possible design, the target radio access technology type is the fourth radio access technology type, and the method further includes: sending a sixth registration request to the access and mobility management function network element, the sixth registration request being sent by an access network device of the fourth radio access technology type; and receiving a sixth registration response from the access and mobility management function network element, the sixth registration response including a fourth registration area associated with the fourth radio access technology type. Furthermore, the method further includes: storing an association between the fourth radio access technology type and the fourth registration area.

[0049] In one possible design, the target wireless access technology type is determined by the second terminal, and the method further includes: sending a fifth message to the access and mobility management function network element, the fifth message including indication information of the target wireless access technology type.

[0050] In one possible design, the target wireless access technology type is determined by the access and mobility management function network element, and the method also includes: receiving a sixth message from the access and mobility management function network element, the sixth message including indication information of the target wireless access technology type.

[0051] In one possible design, the method further includes: determining a fourth cell based on the third wireless access technology type, where the fourth cell is a cell provided by an access network device corresponding to the third wireless access technology type.

[0052] In one possible design, the state of the second terminal corresponding to the third wireless access technology type is an idle state.

[0053] In a sixth aspect, a device is provided that can implement the method of the first or fourth aspect. For example, the device includes means for performing the corresponding method of the first or fourth aspect. The device can be implemented through hardware, software, or hardware executing the corresponding software implementation.

[0054] In one possible design, the device includes a unit that performs the first aspect or the fourth aspect described above.

[0055] In one possible design, the device includes a processor, which is used to execute the method of the first aspect or the fourth aspect above.

[0056] In one possible design, the device includes a processor and an interface circuit, the interface circuit is used to receive signals from other devices outside the device and transmit them to the processor or send signals from the processor to other devices outside the device, and the processor is used to implement the method in the first or fourth aspect above through logic circuits or executing code instructions.

[0057] In one possible design, the device includes a processor and a memory, and the processor is used to execute a computer program or instruction stored in the memory, so that the device implements the method of the first aspect or the fourth aspect above.

[0058] Optionally, the device may be the first device, or a module or unit (for example, a chip, or a chip system, or a circuit) in the first device that corresponds one-to-one to executing the method / operation / step / action described in the first aspect or the fourth aspect, or may be capable of being used in combination with the first device.

[0059] In a seventh aspect, a device is provided that can implement the method of the second, third, or fifth aspect. For example, the device includes means for executing the corresponding method of the second, third, or fifth aspect. The device can be implemented through hardware, software, or hardware executing the corresponding software implementation.

[0060] In one possible design, the device includes a unit that performs the second aspect, the third aspect, or the fifth aspect described above.

[0061] In one possible design, the device includes a processor, which is used to execute the method of the second aspect, third aspect or fifth aspect above.

[0062] In one possible design, the device includes a processor and an interface circuit, the interface circuit is used to receive signals from other devices outside the device and transmit them to the processor or send signals from the processor to other devices outside the device, and the processor is used to implement the methods in the second, third or fifth aspects above through logic circuits or executing code instructions.

[0063] In one possible design, the device includes a processor and a memory, and the processor is used to execute a computer program or instruction stored in the memory, so that the device implements the method of the second aspect, the third aspect or the fifth aspect mentioned above.

[0064] Optionally, the device may be a second device, or a module or unit (e.g., a chip, or a chip system, or a circuit) in the second device that performs the method / operation / step / action described in the second aspect, the third aspect, or the fifth aspect, or a device that can be used in conjunction with the second device.

[0065] In an eighth aspect, a computer-readable storage medium is provided, storing a computer program or instruction. When the computer program or instruction is executed on a computer, the computer implements the method of any one of the first to fifth aspects above.

[0066] In a ninth aspect, a computer program product is provided, comprising a computer program or instructions, which enables the method of any one of the first to fifth aspects to be executed when the computer program or instructions are executed by a computer.

[0067] In the tenth aspect, a chip is provided, comprising a processor coupled to a memory, and configured to execute a computer program or instruction stored in the memory, so that the chip implements the method of any one of the first to fifth aspects above.

[0068] In the eleventh aspect, a communication system is provided, comprising: a first communication device and a second communication device; wherein the first communication device is used to implement the method of the first aspect above, and the second communication device is used to implement the method of the second or third aspect above; or, the first communication device is used to implement the method of the fourth aspect above, and the second communication device is used to implement the method of the fifth aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] FIG1 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0070] Figures 2a and 2b are schematic diagrams of application scenarios provided by embodiments of the present application;

[0071] 3 to 8 are flowcharts of a paging method according to an embodiment of the present application;

[0072] 9 and 10 are schematic structural diagrams of the device provided in the embodiments of the present application. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solutions and advantages of this application more clear, the application will be further described in detail below with reference to the accompanying drawings. The specific operation methods and functional descriptions in the method embodiments can also be applied to the device embodiments or system embodiments.

[0074] The various numbers and terms such as "first" and "second" used in the embodiments of this application are merely for convenience of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily indicate the order in which they are executed. The order in which the processes are executed should be determined by their functions and internal logic.

[0075] In the embodiments of this application, unless otherwise specified, the number of nouns refers to "singular or plural," that is, "one or more." "At least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural.

[0076] FIG1 shows a possible, non-limiting system schematic diagram. As shown in FIG1 , a communication system 10 includes a terminal 100 , a radio access network (RAN) 200 , and a core network (CN) 300 .

[0077] The terminal 100 may also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. The terminal can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), virtual reality (VR), augmented reality (AR), industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, etc. The terminal can be a mobile phone, head-mounted display device, tablet computer, computer with wireless transceiver function, wearable device, vehicle, drone, helicopter, airplane, ship, robot, robotic arm, smart home device, etc. The embodiments of the present application do not limit the device form of the terminal.

[0078] RAN 200 includes at least one RAN node. Terminal 100 can be connected to the RAN node wirelessly. The RAN node is connected to core network 300 wirelessly or via a wired connection. The core network equipment in core network 300 and the RAN nodes in RAN 200 can be separate physical devices, or they can be a single physical device that integrates the logical functions of the core network device and the logical functions of a wireless access device.

[0079] RAN 200 may be a cellular system related to the Third Generation Partnership Project (3GPP), such as a fourth-generation (4G) mobile communication system, a fifth-generation (5G) mobile communication system, or a future-oriented evolutionary system, such as a sixth-generation (6G) mobile communication system. RAN 200 may also be an open access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system. RAN 200 may also be a communication system that integrates two or more of the above systems.

[0080] In one possible scenario, the RAN node may be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next generation NodeB (gNB), a next generation base station in a 6G mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system. The RAN node may be a macro base station, a micro base station or an indoor station, a relay node or a donor node, or a wireless controller in a CRAN scenario. Optionally, the RAN node may also be a server, a wearable device, a vehicle or an on-board device, etc. For example, the access network device in the vehicle to everything (V2X) technology may be a road side unit (RSU). All or part of the functions of the RAN node in the embodiment of the present application may also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (e.g., a cloud platform). The RAN node in the embodiment of the present application may also be a logical node, a logical module, or software that can implement all or part of the functions of the RAN node.

[0081] In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, and different RAN nodes respectively implement part of the functions of the base station. For example, the RAN node can be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be set separately, or they can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0082] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (Open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0083] RAN nodes, sometimes also referred to as access network equipment, RAN entities, or access nodes, constitute part of a communication system and are used to help terminals achieve wireless access. In the subsequent description of this application, unless otherwise specified, "access network equipment" is used for description. The multiple RAN nodes in RAN 200 can be nodes of the same type or different types. In the access network service-oriented architecture, "access network equipment" can also be replaced by access network function (ANF) network elements.

[0084] The core network 300 includes a user plane function (UPF) network element, an access and mobility management function (AMF) network element, and a session management function (SMF) network element. In the embodiment of the present application, the access and mobility management function network element can be replaced by an access management function network element or a registration management function network element.

[0085] The UPF network element is primarily responsible for forwarding and receiving user data from the terminal. For example, the UPF can receive user data from the data network (DN) and forward it to the terminal via access network equipment. Alternatively, the UPF can receive user data from the terminal and forward it to the DN. The transmission resources and scheduling functions provided by the UPF network element to the terminal are managed and controlled by the SMF network element.

[0086] The AMF network element is mainly responsible for signaling processing, such as access control, mobility management, attachment and detachment, and gateway selection. When the AMF network element provides services for a session in a terminal, it can provide control plane storage resources for the session to store the session identifier and the SMF network element identifier associated with the session identifier.

[0087] The SMF network element is mainly responsible for user plane network element selection, user plane network element redirection, Internet protocol (IP) address allocation, bearer establishment, modification and release, and quality of service (QoS) control.

[0088] Optionally, the communication system 10 also includes DN400. Terminals, access network devices, UPF network elements, and DNs are generally referred to as user plane functions and entities. User data streams can be transmitted through protocol data unit (PDU) sessions established between the terminal and the DN. The user plane is used to carry service data. Other network elements in the communication system 10, such as SMF network elements and AMF network elements, can be referred to as control plane functions and entities, which are mainly responsible for functions such as authentication and authorization, registration management, session management, mobility management, and policy control, thereby achieving reliable and stable transmission of user plane data streams. The control plane is used to carry signaling messages.

[0089] In the embodiment of the present application, the terminal and the AMF network element can interact through the N1 interface, and the messages exchanged between the two can be called N1 messages. Similarly, the interfaces between the access network device and the AMF network element, and the interfaces between the access network device and the UPF network element are N2 interfaces and N3 interfaces, respectively, and the messages exchanged therebetween can be called N2 messages and N3 messages, respectively. The interface between the UPF network element and the SMF network element is the N4 interface, the interface between the UPF network element and the DN is the N6 interface, and the interface between the AMF network element and the SMF network element is the N11 interface. The messages exchanged therebetween can be called N4 messages, N6 messages, and N11 messages, etc.

[0090] It is understandable that the names of the various network elements in the core network 300 are not limited. For example, in the 5G communication system, the network element that implements the signaling processing part is called the AMF network element. In the 6G communication system, the network element that implements the above functions can also be called other names, etc., without limitation. In the subsequent description, the names of the various network elements in 5G are mainly used as examples to describe the scheme of the embodiment of the present application. Optionally, the core network 300 may also include other network elements of control plane functions and entities. For example, network exposure function (NEF) network element, application function (AF) network element, policy control function (PCF) network element, network slice selection function (NSSF) network element, unified data management (UDM) network element, authentication server function (AUSF) network element, network repository function (NRF) network element, unified data storage function (UDR) network element, network data analysis function (NWDAF) network element, etc.

[0091] It can be understood that access network equipment, terminals and network elements in the core network can be called communication devices. For example, access network equipment can be understood as communication devices with base station functions, terminals can be understood as communication devices with terminal functions, and network elements in the core network, such as AMF, can be understood as communication devices with AMF functions.

[0092] With the development of communication technology, terminals may have dual connectivity. Installed with a subscriber identity module (SIM) card, the terminal can connect to two access network devices, maintain radio resource control (RRC) signaling connections with both access network devices, and transmit the same or different data through the two access network devices.

[0093] For example, as shown in Figure 2a, the terminal is connected to the same AMF network element through two access network devices. Or, as shown in Figure 2b, the terminal is connected to different AMF network elements through two access network devices. In Figure 2b, the two AMF network elements may belong to the same or different public land mobile networks (PLMN) without restriction. Both access network devices are 3GPP access type access network devices, and the two access network devices have different radio access technology (RAT) types. For example, the RAT type of access network device 1 is 5G RAT, and the RAT type of access network device 2 is 6G RAT. For another example, the RAT type of access network device 1 is 5G new radio (NR), and the RAT type of access network device 2 is satellite 5G NR.

[0094] During the downlink data transmission of the terminal, when the UPF network element receives downlink data from the DN, the UPF network element may send a data notification to the SMF network element, and the SMF network element may send a data notification acknowledgment (data notification Ack) to the UPF network element. The SMF network element may send an N1N2 message transfer to the AMF network element, and the AMF network element may send an N1N2 message transfer response to the SMF network element. When the terminal is in an idle state, how the AMF network element determines one access network device of two different RAT types to page the terminal in order to restore the communication connection of the session is a technical problem to be solved in the embodiments of the present application.

[0095] In view of this, an embodiment of the present application provides a paging method, including: when the AMF network element receives a first message from the SMF network element, the first message includes an identifier of the first session of the first terminal. Optionally, the first session may be a first PDU session. In the following description, the first PDU session is taken as an example. The AMF network element sends a first paging message to the first access network device corresponding to the first RAT type associated with the first PDU session, thereby implementing paging of the first terminal and restoring the communication connection of the first PDU session.

[0096] As shown in FIG3 , a flow chart is provided, including:

[0097] Step 300: The SMF network element sends a first message to the AMF network element, and the AMF network element receives the first message from the SMF network element.

[0098] In one possible implementation, when the SMF network element receives a downlink data notification for a first PDU session of a first terminal from the UPF network element, the SMF network element sends a first message to the AMF network element. Optionally, the first message may be an N1N2 message transfer message. The first message includes an identifier of the first PDU session of the first terminal. The AMF network element may determine the first RAT type associated with the first PDU session based on a stored association between the first PDU session and the first RAT type. For example, the first terminal sends a PDU session establishment request message to the AMF network element via an access network device of the first RAT type. The PDU session establishment request message includes the identifier of the first PDU session. The PDU session establishment request is used to request establishment of the first PDU session. Upon receiving the PDU session establishment request, the AMF network element may establish an association between the first PDU session and the first RAT type. The AMF network element may maintain the status of the first terminal in the first RAT type and the second RAT type. When the status of the first terminal maintained by the AMF in the first RAT is idle, in step 310, the AMF network element pages the first terminal via the first access network device corresponding to the first RAT type. In the description of the embodiments of the present application, the association relationship between the first PDU session and the first RAT type can also be described as: the first PDU session is associated with the first RAT type, or the first terminal establishes the first PDU session through the access network device corresponding to the first RAT type, or the first PDU session is established on the access network device corresponding to the first RAT type, etc.

[0099] In this embodiment of the present application, the first terminal registers (or connects) to the AMF network element through an access network device of a first RAT type and an access network device of a second RAT type, where the first RAT type is different from the second RAT type. For example, the first RAT type is 5G RAT and the second RAT type is 6G RAT. Alternatively, the first RAT type is 5G NR and the second RAT type is satellite 5G NR.

[0100] Step 310: The AMF network element sends a first paging message to the first access network device corresponding to the first RAT type, and the first access network device corresponding to the first RAT type receives the first paging message from the AMF network element. The first paging message includes the first identifier of the first terminal.

[0101] Optionally, the first paging message is a next generation access point (NGAP) paging message.

[0102] Step 320: The first access network device of the first RAT type sends a paging message (in the following description, the paging message may be referred to as a second paging message or a third paging message), where the paging message includes the first identifier of the first terminal.

[0103] In one possible implementation, upon receiving the paging message, the first terminal determines whether the first terminal identifier included in the paging message belongs to the first terminal. If so, this indicates that the network is paging the first terminal. The first terminal may restore or establish an RRC connection with the access network device of the first RAT type. Furthermore, in step 330, the first terminal requests restoration of the communication connection for the first PDU session associated with the first RAT type.

[0104] Step 330: The first terminal sends a message (hereinafter referred to as the second message or the third message) to the AMF network element through the access network device corresponding to the first RAT type. The message includes an identifier of the first PDU session and is used to request restoration of the communication connection of the first PDU session. Optionally, the message may be a service request message.

[0105] In the description of this application, the first access network device corresponding to the first RAT type may refer to one access network device or multiple access network devices. In one possible implementation, the RAT types include: 5G RAT and 6G RAT. 5G RAT can be divided into: 5G NR and satellite 5G NR. Satellite 5G NR can be divided into low earth orbit (LEO), medium earth orbit (MEO), and geostationary earth orbit (GEO).

[0106] The following uses four examples to illustrate the solution in the process of Figure 3 in detail.

[0107] Example 1: A first terminal is connected to the same AMF network element through an access network device of a first RAT type and an access network device of a second RAT type. The AMF network element allocates corresponding registration areas (RAs) for different RAT types and stores the correspondence between RAT types and RAs. The AMF network element sends a first paging message to the access network corresponding to the RA corresponding to the RAT type.

[0108] As shown in FIG4 , a flow chart is provided, including:

[0109] Step 400: A first terminal sends a first registration request to an AMF network element via an access network device of a first RAT type. The AMF network element receives the first registration request from the first terminal via the access network device of the first RAT type.

[0110] For example, when the AMF network element receives the first registration request, the AMF network element allocates a first RA corresponding to the first RAT type, and the AMF network element stores the association relationship between the first RAT type and the first RA. Optionally, the first registration request may be referred to as a registration request message.

[0111] Optionally, when the first registration request includes capability information that the first terminal supports accessing the network through two access network devices, the AMF network element allocates the corresponding first RA for the first RAT type; if the first registration request does not include capability information that the first terminal supports accessing the network through two access network devices of 3GPP access types, the AMF network element allocates the corresponding first RA for the 3GPP access type, but the first RAT type is not associated with the first RA.

[0112] Optionally, when the first terminal registers with the AMF network element only through the access network device of the first RAT type, the AMF network element allocates the corresponding first RA for the 3GPP access type, but the first RAT type is not associated with the first RA.

[0113] Optionally, the AMF network element obtains from the PCF network element or the UDM network element whether the first terminal is authorized to access the network through two access network devices of 3GPP access types. If the first terminal is authorized to access the network through two access network devices, the AMF network element allocates a corresponding first RA for the first RAT type; if the first terminal is not authorized to access the network through two access network devices, the AMF network element allocates a corresponding registration area for the 3GPP access type.

[0114] Step 410: The AMF network element sends a first registration response to the first terminal, and the first terminal receives the first registration response from the AMF network element. Optionally, the first registration response includes a first RA corresponding to the first RAT type.

[0115] For example, the first terminal obtains the first RA corresponding to the first RAT type in the first registration response, and the first terminal stores the association relationship between the first RAT type and the first RA. It can be understood that the first registration response is transmitted through the access network device corresponding to the first RAT type. For example, the AMF network element can send the first registration response to the first terminal through the access network device corresponding to the first RAT type, and the first terminal can receive the first registration response from the AMF network element through the access network device corresponding to the first RAT type. Optionally, the first registration response can be called a registration accept message.

[0116] Optionally, at this time, the first terminal maintained by the AMF network element is in a connected state in the first RAT type.

[0117] Step 420: The first terminal sends a second registration request to the AMF network element through the access network device of the second RAT type, and the AMF network element receives the second registration request from the first terminal through the access network device of the second RAT type.

[0118] For example, when the AMF network element receives the second registration request, the AMF network element allocates a corresponding second RA for the second RAT type, and the AMF network element stores the association relationship between the second RAT type and the second RA. Optionally, the second registration request may be referred to as a registration request message.

[0119] It should be noted that, when the first terminal is in dual connection mode or wishes to access the network through dual connection, step 420 is executed.

[0120] Optionally, when the first terminal sends a registration request to the AMF network element through the access network device of the first RAT type (step 400), the AMF network element allocates a first RA corresponding to the 3GPP access type. When the first terminal sends a registration request to the AMF network element through the access network device of the second RAT type (step 420), the AMF network element allocates a second RA corresponding to the second RAT type and establishes an association between the first RAT type and the first RA.

[0121] Step 430: The AMF network element sends a second registration response to the first terminal, and the first terminal receives the second registration response from the AMF network element. Optionally, the second registration response includes a second RA corresponding to the second RAT type.

[0122] For example, the first terminal obtains the second RA corresponding to the second RAT type in the second registration response, and the first terminal stores the association relationship between the second RAT type and the second RA. It can be understood that the AMF network element can send the second registration response to the first terminal through the access network device corresponding to the second RAT type, and the first terminal can receive the second registration response from the AMF network element through the access network device corresponding to the second RAT type. Optionally, the second registration response can be called a registration accept message.

[0123] Optionally, at this time, the first terminal maintained by the AMF network element is in a connected state in the second RAT type.

[0124] Step 440: The first terminal establishes a first PDU session through an access network device of the first RAT type.

[0125] In one possible implementation, the first terminal sends a PDU session establishment request message to the AMF network element through the access network device of the first RAT type. The PDU session establishment request message includes the identifier of the first PDU session. After the AMF network element selects the SMF network element, it sends a session management context establishment request message to the SMF network element. The session management context establishment request message includes the identifier of the first PDU session. The SMF network element selects UPF for the first PDU session and establishes a transmission channel between the access network device of the first RAT type and the UPF.

[0126] In downlink data transmission, the transmission path of the data of the first PDU session is: DN → UPF → access network device of the first RAT type → first terminal. The data of the first PDU session is transmitted through the access network device of the first RAT type. The AMF network element and the first terminal may store the association relationship between the first PDU session and the first RAT type. Optionally, the AMF network element may also send the association relationship between the first PDU session and the first RAT type to the SMF network element, which stores the association relationship between the first PDU session and the first RAT type.

[0127] Step 460: When the SMF network element receives the downlink data notification of the first PDU session from the UPF network element, the SMF network element sends a first message to the AMF network element, and the AMF network element receives the first message from the SMF network element. Optionally, the first message can be an N1N2 message transfer message.

[0128] Among them, the first message includes the identifier of the first PDU session. Optionally, the first message also includes indication information of the first RAT type. In a possible implementation, it has been explained in step 440 that the SMF network element may store the association relationship between the first PDU session and the first RAT type. When the SMF network element receives the downlink data notification of the first PDU session from the UPF network element, the SMF network element may determine the first RAT type corresponding to the first PDU session based on the stored association relationship between the first PDU session and the first RAT type, and notify the AMF network element of the first RAT type through the first message. Further, optionally, the first message also includes indication information of the 3GPP access type. For example, when the AMF network element receives the first message, when the indication information of the 3GPP access type is obtained in the first message, subsequent steps 470a to 4010 are executed.

[0129] In one possible implementation, the AMF network element may maintain states corresponding to the first RAT type and the second RAT type for the first terminal. For example, the first terminal is disconnected from the access network device of the first RAT type, so the state of the first terminal corresponding to the first RAT type maintained by the AMF network element is an idle state. If the first terminal remains connected to the access network device of the second RAT type, the state of the first terminal corresponding to the second RAT type maintained by the AMF network element is a connected state; otherwise, it is an idle state.

[0130] Case 1: The first terminal is disconnected from both the first RAT type access network device and the second RAT type access network device. Optionally, at this point, the first terminal maintained by the AMF network element is in an idle state in both the first RAT type and the second RAT type. For Case 1, execute steps 470a, 480a, and 490a.

[0131] In one possible implementation, since the first PDU session is established through the access network device of the first RAT type, when the connection between the first terminal and the access network device of the first RAT type is disconnected, the communication of the first PDU session will be interrupted. The AMF network element may page the first terminal through subsequent steps, thereby restoring or establishing the connection between the first terminal and the access network device of the first RAT type, and further restoring the communication connection of the first PDU session.

[0132] Step 470a: The AMF network element sends a first paging message to a first access network device corresponding to the first RAT type. The first access network device corresponding to the first RAT type receives the first paging message from the AMF network element. The first paging message includes the first identifier of the first terminal. Optionally, the first paging message may be an NGAP paging message.

[0133] In the description of step 440, the AMF network element stores an association relationship between the first PDU session and the first RAT type. Therefore, in step 470a, the AMF network element may determine the first RAT type associated with the first PDU session based on the stored association relationship between the first PDU session and the first RAT type. In one possible implementation, the AMF network element determines the first RAT type associated with the first PDU session based on the association relationship between the PDU session and the RAT type. Since in addition to the first PDU session, there may be other PDU sessions in the communication system, the AMF network element may store an association relationship between at least one PDU session and the RAT type. The AMF network element queries the first RAT type associated with the first PDU session in its stored association relationship. Alternatively, the first message includes indication information of the first RAT type, and the AMF network element may determine the first RAT type based on the indication information of the first RAT type included in the first message.

[0134] In the description of step 400, the AMF network element stores the association relationship between the first RAT type and the first RA. The AMF network element may determine the first RA corresponding to the first RAT type based on the stored association relationship between the first RAT type and the first RA. Optionally, the RA includes a tracking area identity (TAI) list, the TAI list includes at least one tracking area (TA), and each TA includes at least one cell. The AMF network element may determine at least one cell based on the first RA. The AMF network element determines the access network device that provides the at least one cell, which is referred to as the first access network device in step 470a. The first access network device is in the first RA corresponding to the first RAT type. It will be understood that the first access network device may refer to one or more access network devices.

[0135] Optionally, the first identifier of the first terminal may be a short-temporary mobile subscriber identity (S-TMSI) of the first terminal. In addition to the first identifier of the first terminal, the first paging message may also include indication information of the first RAT type.

[0136] Step 480a: The first access network device corresponding to the first RAT type sends a second paging message, and the first terminal receives the second paging message through the first access network device corresponding to the first RAT type. The second paging message includes the first identifier of the first terminal.

[0137] For example, a first access network device corresponding to a first RAT type may broadcast a second paging message. When a first terminal is within a reception area of ​​the broadcast, the first terminal may receive the second paging message. Optionally, the first terminal determines whether the terminal identifier included in the second paging message is its own identifier. If it is its own identifier, i.e., the identifier of the first terminal, then the network is paging the first terminal, and the first terminal may restore the RRC connection with the access network device of the first RAT type. Otherwise, the first terminal may remain in an idle state.

[0138] Step 490a: The first terminal determines the first RAT type according to the second paging message.

[0139] In one possible implementation, the first terminal determines the first RAT type based on the second paging message. For example, the second paging message includes indication information of the first RAT type. The first terminal determines the first RAT type based on the indication information of the first RAT type. Alternatively, the first terminal determines the first RAT type based on the radio resource used to receive the second paging message. For example, different RAT types may use different radio resources to transmit the second paging message, with the first RAT type corresponding to the first radio resource and the second RAT type corresponding to the second radio resource. When the radio resource used to receive the second paging message is the first radio resource, the first terminal may determine the first RAT type corresponding to the first radio resource.

[0140] In step 440, the first terminal stores the association between the first RAT type and the first PDU session. The first terminal may determine the first PDU session based on the stored association between the first RAT type and the first PDU session. The first terminal may request to restore the communication connection of the first PDU session in step 4010.

[0141] Case 2: The first terminal is disconnected from the access network device of the first RAT type, but remains connected to the access network device of the second RAT type. Optionally, at this time, the first terminal maintained by the AMF network element is in an idle state for the first RAT type, and the first terminal maintained by the AMF network element is in a connected state for the second RAT type. For Case 2, execute step 470b.

[0142] Step 470b: The AMF network element sends a non-access stratum (NAS) notification message to the first terminal via the access network device of the second RAT type. The first terminal receives the NAS notification message from the AMF network element via the access network device of the second RAT type, where the NAS notification message includes indication information of the first RAT type.

[0143] In one possible implementation, the first terminal may determine the first PDU session according to the association between the first RAT type and the first PDU session stored in step 440. In step 4010, the first terminal requests to resume the communication connection of the first PDU session.

[0144] Step 4010: The first terminal sends a second message to the AMF network element through the second access network device corresponding to the first RAT type; the AMF network element receives the second message from the first terminal through the second access network device corresponding to the first RAT type.

[0145] In one possible implementation, before requesting to resume the communication connection for the first PDU session in step 4010, the first terminal establishes an RRC connection with a second access network device corresponding to the first RAT type. Subsequently, in step 4010, the first terminal sends a second message to the AMF network element via the second access network device corresponding to the first RAT type. For example, the first terminal determines a first cell based on the first RAT type, where the first cell is a cell provided by the second access network device. In one possible implementation, the access network device has at least one cell, and the access network device can send a broadcast message via the at least one cell. The broadcast message includes information indicating the RAT type of the access network device. From the received broadcast message, the first terminal selects a cell with the first RAT type, referred to as the first cell. It will be appreciated that the first cell may refer to one cell or multiple cells. The first terminal establishes an RRC connection with the second access network device providing the first cell. Optionally, the second access network device may refer to one access network device.

[0146] In one possible implementation, the first terminal sends a second message to a second access network device corresponding to the first RAT type, and the second access network device of the first RAT type sends the second message to the AMF network element. The second message includes an identifier of the first PDU session associated with the first RAT type, and the second message is used to request the restoration of the communication connection of the first PDU session. Optionally, the second message may be a service request message. Optionally, upon receiving the second message, the AMF network element may send a notification message to the SMF network element, which in turn restores the communication connection of the first PDU session.

[0147] It is understandable that in the scenario of Case 2, the AMF network element can also adopt the solution in Case 1 to restore the communication connection of the first PDU session without restriction.

[0148] In an embodiment of the present application, the first paging message, the second paging message, or the NAS notification message includes indication information of the first RAT type. The indication information of the first RAT type is used to instruct the first terminal to restore the connection with the access network device of the first RAT type. For example, the first terminal is instructed to restore the air interface connection and the upper layer service connection with the access network device of the first RAT type, for example, to restore the communication connection of the first PDU session corresponding to the first RAT type. Alternatively, the indication information of the first RAT type is used to indicate the arrival of downlink data of the first PDU session corresponding to the first RAT type, so the first terminal needs to restore the air interface connection and the upper layer service connection between the first terminal and the access network device of the first RAT type.

[0149] Through the above method, when the first terminal adopts a dual 3GPP access mode to access two access network devices, and the RAT types of the two access network devices are different: when the AMF receives a notification of the arrival of downlink data of a certain PDU session, the AMF network element can determine a certain RAT type based on the association between the PDU session and the RAT type. Furthermore, the AMF network element determines the RA corresponding to the RAT type based on the maintained correspondence between different RAT types and RAs. The AMF pages the first terminal through the access network device corresponding to the RA, thereby achieving paging of the first terminal and further restoring the communication connection of the PDU session.

[0150] Example 2: A first terminal connects to the same AMF network element through an access network device of a first RAT type and an access network device of a second RAT type. The AMF network element assigns different first terminal identifiers to different RAT types and stores the correspondence between the RAT types and the first terminal identifiers. The first terminal determines the first RAT type based on the first terminal identifier included in the paging message.

[0151] As shown in FIG5 , a flow chart is provided, including:

[0152] Step 500: The first terminal sends a third registration request to the AMF network element through the first RAT type access network device. The AMF network element receives the third registration request from the first terminal through the first RAT type access network device.

[0153] Step 510: The AMF network element sends a third registration response to the first terminal via the access network device of the first RAT type. The first terminal receives the third registration response from the AMF network element via the access network device of the first RAT type.

[0154] In one possible implementation, when the AMF network element receives the third registration request, the AMF network element allocates the second identifier of the first terminal to the first RAT type. The third registration response includes the second identifier of the first terminal. Optionally, the second identifier of the first terminal may be a globally unique temporary UE identity (GUTI) of the first terminal. The second identifier of the first terminal includes the first identifier of the first terminal. Optionally, the first identifier of the first terminal may be an S-TMSI of the first terminal. The AMF network element and the first terminal may store an association between the second identifier of the first terminal and the first RAT type, or store an association between the first identifier of the first terminal and the first RAT type.

[0155] Optionally, when the third registration request includes capability information that the first terminal supports accessing the network through two access network devices, the AMF network element allocates the second identifier of the first terminal to the first RAT type; if the first registration request does not include capability information that the first terminal supports accessing the network through two 3GPP access types of access network devices, the AMF network element allocates the second identifier of the first terminal, but the second identifier of the first terminal is not associated with the first RAT type.

[0156] Optionally, when the first terminal registers with the AMF network element only through the access network device of the first RAT type, the AMF network element allocates a second identifier to the first terminal, but the second identifier of the first terminal is not associated with the first RAT type.

[0157] Optionally, the AMF network element obtains from the PCF network element or the UDM network element whether the first terminal is authorized to access the network through two access network devices of 3GPP access types. If the first terminal is authorized to access the network through two access network devices, the AMF network element allocates the second identifier of the first terminal to the first RAT type; if the first terminal is not authorized to access the network through two access network devices, the AMF network element allocates the second identifier of the first terminal, but the second identifier of the first terminal is not associated with the first RAT type.

[0158] Optionally, at this time, the first terminal maintained by the AMF network element is in a connected state in the first RAT type.

[0159] Step 520: The first terminal sends a fourth registration request to the AMF network element through the access network device of the second RAT type. The AMF network element receives the fourth registration request from the first terminal through the access network device of the second RAT type.

[0160] It should be noted that, when the first terminal is in dual connection mode or wishes to access the network through dual connection, step 520 is executed.

[0161] Step 530: The AMF network element sends a fourth registration response to the first terminal via the access network device of the second RAT type. The first terminal receives the fourth registration response from the AMF network element via the access network device of the second RAT type.

[0162] In one possible implementation, when the AMF network element receives the fourth registration request, the AMF network element allocates the third identifier of the first terminal to the second RAT type. Optionally, the third identifier of the first terminal may be the GUTI of the first terminal. The fourth registration response includes the third identifier of the first terminal. The third identifier of the first terminal includes the fourth identifier of the first terminal. Optionally, the fourth identifier of the first terminal may be the S-TMSI of the first terminal. The AMF network element and the first terminal may store the association between the third identifier of the first terminal and the second RAT type, or store the association between the fourth identifier of the first terminal and the second RAT type.

[0163] In one possible implementation, the third registration request and the fourth registration request may be registration request messages. The third registration response and the fourth registration response may be registration accept messages. When the first RAT type or the second RAT type is a 5G RAT, the GUTI of the first terminal is a 5G-GUTI, and the S-TMSI of the first terminal is a 5G-S-TMSI. Alternatively, when the first RAT type or the second RAT type is a 6G RAT, the GUTI of the first terminal is a 6G-GUTI, and the S-TMSI of the first terminal is a 6G-S-TMSI.

[0164] Optionally, when the first terminal sends a registration request to the AMF network element through the access network device of the first RAT type (step 500), the AMF network element allocates a second identifier of the first terminal, but the second identifier of the first terminal is not associated with the first RAT type. When the first terminal sends a registration request to the AMF network element again through the access network device of the second RAT type (step 520), the AMF network element allocates the third identifier of the first terminal for the second RAT type, and establishes an association between the second identifier of the first terminal and the first RAT type.

[0165] Optionally, at this time, the first terminal maintained by the AMF network element is in a connected state in the second RAT type.

[0166] Step 540: The first terminal establishes a first PDU session through an access network device of the first RAT type.

[0167] In one possible implementation, the AMF network element and the first terminal may store the association relationship between the first PDU session and the first RAT type. Optionally, the AMF network element may also send the association relationship between the first PDU session and the first RAT type to the SMF network element, and the SMF network element stores the association relationship between the first PDU session and the first RAT type.

[0168] Step 560: When the SMF network element receives a downlink data notification for the first PDU session from the UPF network element, the SMF network element sends a first message to the AMF network element. The AMF network element receives the first message from the SMF network element. Optionally, the first message may be an N1N2 message transfer message.

[0169] The first message includes an identifier of the first PDU session. Optionally, the first message also includes indication information of the first RAT type. Further, the first message also includes indication information of the 3GPP access type.

[0170] In one possible implementation, upon receiving the first message, the AMF network element may obtain an identifier of the first PDU session in the first message. The AMF network element determines the first RAT type based on a stored association between the first PDU session and the first RAT type.

[0171] In another possible implementation, when the SMF network element receives the downlink data notification of the first PDU session, the SMF network element may determine the first RAT type based on the stored association relationship between the first PDU session and the first RAT type. The first message sent by the SMF network element to the AMF network element includes indication information of the first RAT type. The AMF network element determines the first RAT type based on the indication information of the first RAT type included in the first message.

[0172] Step 570: The AMF network element determines the first identifier of the first terminal based on the first RAT type.

[0173] In one possible implementation, the AMF network element determines the first identifier of the first terminal based on a stored association between the first RAT type and the first identifier of the first terminal. Alternatively, the AMF network element determines the second identifier of the first terminal based on a stored association between the first RAT type and the second identifier of the first terminal. Because the second identifier of the first terminal includes the first identifier of the first terminal, the terminal can obtain the first identifier of the first terminal from the second identifier of the first terminal.

[0174] Case 1: The first terminal is disconnected from both the first RAT type access network device and the second RAT type access network device. Optionally, at this point, the first terminal maintained by the AMF network element is in an idle state for both the first RAT type and the second RAT type. For Case 1, execute steps 580a and 590a.

[0175] Step 580a: The AMF network element sends a first paging message to a first access network device corresponding to the first RAT type. The first access network device of the first RAT type receives the first paging message from the AMF network element. The first paging message includes the first identifier of the first terminal. Optionally, the first paging message may be an NGAP paging message.

[0176] Step 590a: The first access network device corresponding to the first RAT type sends a second paging message, and the first terminal receives the second paging message through the first access network device corresponding to the first RAT type. The second paging message includes the first identifier of the first terminal.

[0177] For the implementation process of step 580a and step 590a, please refer to the description of step 470a and step 480a. The difference is that when the first terminal receives the second paging message, it obtains the first identifier of the first terminal in the second paging message. The first terminal determines the first RAT type based on the first identifier of the first terminal. For example, the first terminal may determine the first RAT type based on the stored association relationship between the first identifier of the first terminal and the first RAT type, or based on the stored association relationship between the second identifier of the first terminal and the first RAT type. Further, optionally, the first terminal determines the first PDU session based on the stored association relationship between the first PDU session and the first RAT type. In step 5010, the first terminal restores the communication connection of the first PDU session through the second access network device of the first RAT type.

[0178] Case 2: The first terminal loses connection with the access network device of the first RAT type, but remains connected to the access network device of the second RAT type. Optionally, at this point, the first terminal maintained by the AMF network element is in an idle state for the first RAT type, and in a connected state for the second RAT type. For Case 2, proceed to step 580b.

[0179] Step 580b: The AMF network element sends an NAS notification message to the first terminal via the access network device of the second RAT type. The first terminal receives the NAS notification message from the AMF network element via the access network device of the second RAT type. The NAS notification message includes the first identifier of the first terminal.

[0180] In one possible implementation, when the first terminal receives a NAS notification message, the first terminal obtains the first identifier of the first terminal in the NAS notification message. The first terminal determines the first identifier of the first terminal based on the stored association relationship between the first identifier of the first terminal and the first RAT type. Alternatively, the first terminal determines the second identifier of the first terminal corresponding to the first identifier of the first terminal, and determines the first RAT type based on the stored association relationship between the second identifier of the first terminal and the first RAT type. Further, optionally, the first terminal determines the first PDU session based on the stored association relationship between the first PDU session and the first RAT type. In step 5010, the communication connection of the first PDU session is restored through the second access network device of the first RAT type.

[0181] Step 5010: The first terminal sends a second message to the AMF network element through the second access network device corresponding to the first RAT type; the AMF network element receives the second message from the first terminal through the second access network device corresponding to the first RAT type.

[0182] For the implementation process of step 5010, please refer to the description in step 4010.

[0183] It is understandable that in the scenario of Case 2, the AMF network element can also adopt the solution in Case 1 to restore the communication connection of the first PDU session without restriction.

[0184] Through the above method, since the identifier of the first terminal is associated with the RAT type, when paging the first terminal, it is sufficient to carry the identifier of the first terminal corresponding to the RAT type in the paging message without the need for paging enhancement, for example, avoiding carrying indication information of the RAT type in the paging message, etc., thereby saving the overhead of the paging message.

[0185] Example 3 differs from Example 2 in that: the first terminal accesses or registers with the first AMF network element through an access network device of the first RAT type, and the first AMF network element allocates the first terminal's identifier for the first RAT type. The second terminal accesses or registers with the second AMF network element through an access network device of the second RAT type, and the second AMF network element allocates the first terminal's identifier for the second RAT type.

[0186] As shown in FIG6 , a flow chart is provided, including:

[0187] Step 600: The first terminal sends a seventh registration request to the first AMF network element via the first RAT type access network device. The first AMF network element receives the seventh registration request from the first terminal via the first RAT type access network device.

[0188] Step 610: The first AMF network element sends a seventh registration response to the first terminal via the first RAT type access network device. The first terminal receives the seventh registration response from the first AMF network element via the first RAT type access network device.

[0189] In one possible implementation, the seventh registration response includes the second identifier of the first terminal, and the second identifier of the first terminal includes the first identifier of the first terminal. The first AMF network element and the first terminal may store an association between the second identifier of the first terminal and the first RAT type, or store an association between the first identifier of the first terminal and the first RAT type.

[0190] Optionally, when the seventh registration request includes capability information that the first terminal supports accessing the network through two access network devices, the AMF network element allocates the second identifier of the first terminal to the first RAT type; if the seventh registration request does not include capability information that the first terminal supports accessing the network through two access network devices of 3GPP access types, the AMF network element allocates the second identifier of the first terminal, but the second identifier of the first terminal is not associated with the first RAT type.

[0191] Optionally, when the first terminal registers with the AMF network element only through the access network device of the first RAT type, the AMF network element allocates a second identifier to the first terminal, but the second identifier of the first terminal is not associated with the first RAT type.

[0192] Optionally, the AMF network element obtains from the PCF network element or the UDM network element whether the first terminal is authorized to access the network through two access network devices of 3GPP access types. If the first terminal is authorized to access the network through two access network devices, the AMF network element allocates the second identifier of the first terminal to the first RAT type; if the first terminal is not authorized to access the network through two access network devices, the AMF network element allocates the second identifier of the first terminal, but the second identifier of the first terminal is not associated with the first RAT type.

[0193] Optionally, at this time, the first terminal maintained by the first AMF network element is in a connected state in the first RAT type.

[0194] Step 620: The first terminal sends an eighth registration request to the second AMF network element through the access network device of the second RAT type. The second AMF network element receives the eighth registration request from the first terminal through the access network device of the second RAT type.

[0195] It should be noted that, when the first terminal is in dual connection mode or wishes to access the network through dual connection, step 620 is executed.

[0196] Step 630: The second AMF network element sends an eighth registration response to the first terminal through the access network device of the second RAT type. The first terminal receives the eighth registration response from the second AMF network element through the access network device of the second RAT type.

[0197] In one possible implementation, the eighth registration response includes the third identifier of the first terminal, and the third identifier of the first terminal includes the fourth identifier of the first terminal. The second AMF network element and the first terminal may store an association between the third identifier of the first terminal and the second RAT type, or store an association between the fourth identifier of the first terminal and the second RAT type.

[0198] In a possible implementation, the seventh registration request and the eighth registration request may be registration request messages, and the seventh registration response and the eighth registration response may be registration accept messages.

[0199] Optionally, when the first terminal sends a registration request to the AMF network element through the access network device of the first RAT type (step 600), the AMF network element allocates the second identifier of the first terminal, but the second identifier of the first terminal is not associated with the first RAT type. When the first terminal sends a registration request to the AMF network element again through the access network device of the second RAT type (step 620), the AMF network element allocates the third identifier of the first terminal for the second RAT type and establishes an association between the second identifier of the first terminal and the first RAT type.

[0200] Optionally, at this time, the first terminal maintained by the second AMF network element is in a connected state in the second RAT type.

[0201] Step 640: The first terminal establishes a first PDU session through an access network device of the first RAT type.

[0202] In one possible implementation, the first AMF network element and the first terminal store the association relationship between the first RAT type and the first PDU session. Optionally, the first AMF network element may send the association relationship between the first RAT type and the first PDU session to the SMF network element, and the SMF network element stores the association relationship between the first RAT type and the first PDU session.

[0203] Step 660: When the SMF network element receives the downlink data notification of the first PDU session from the UPF network element, the SMF network element sends a first message to the first AMF network element. Optionally, the first message can be an N1N2 message transfer message.

[0204] The first message includes an identifier of the first PDU session. Optionally, the first message also includes indication information of the first RAT type. Further, the first message also includes indication information of the 3GPP access type.

[0205] Step 670: The first AMF network element sends a first paging message to a first access network device of the first RAT type. The first access network device of the first RAT type receives the first paging message from the first AMF network element. The first paging message includes the first identifier of the first terminal. Optionally, the first paging message may be an NGAP paging message.

[0206] Step 680: The first access network device of the first RAT type sends a second paging message to the first terminal. The first terminal receives the second paging message from the first access network device of the first RAT type. The second paging message includes the first identifier of the first terminal.

[0207] In one possible implementation, the first terminal may obtain the first identifier of the first terminal in the second paging message. The first terminal determines the first RAT type based on the stored association relationship between the first identifier of the first terminal and the first RAT type, or the association relationship between the second identifier of the first terminal and the first RAT type. The first terminal may determine or select the first cell based on the first RAT type, and the RAT type corresponding to the first cell is the first RAT type. The first terminal may establish an RRC with the second access network device that provides the first cell. It can be understood that the RAT type of the second access network device is also the first RAT type. In step 690, the first terminal sends a second message to the first AMF network element through the second access network device of the first RAT type to request to restore the communication connection of the first PDU session.

[0208] Step 690: The first terminal sends a second message to the first AMF network element through the second access network device corresponding to the first RAT type. The first AMF network element receives the second message from the first terminal through the second access network device of the first RAT type. The second message includes the identifier of the first PDU session associated with the first RAT type. The second message is used to request to restore the communication connection of the first PDU session.

[0209] It is understandable that the solution of Example 3 can be applied in Example 1. For example, the first terminal accesses the first AMF network element through an access network device of the first RAT type, the first AMF network element allocates a first RA for the first RAT type, and the first AMF network element stores the association relationship between the first RAT type and the first RA. The first terminal accesses the second AMF network element through an access network device of the second RAT type, the second AMF network element allocates a second RA for the second RAT type, and the second AMF network element stores the association relationship between the second RAT type and the second RA. When the first PDU session is associated with the first RAT type, the first AMF network element sends a first paging message to the access network device of the first RA corresponding to the first RAT type, etc.

[0210] Through the above method, the first terminal connects to different AMFs via access network devices of different RAT types. The AMF assigns the corresponding first terminal identifier to the corresponding RAT type. The first terminal and the AMF can store the association between the RAT type and the first terminal identifier. When paging the first terminal, the AMF carries the first terminal identifier corresponding to the RAT type in the paging message. The first terminal can determine the corresponding RAT type based on the first terminal identifier included in the paging message, eliminating the need for paging enhancement and saving paging message overhead.

[0211] Example 4: This differs from Example 1 primarily in that a PDU session can be associated with two RAT types. For example, a first PDU session is established via an access network device of a first RAT type and an access network device of a second RAT type. In addition to being associated with the first RAT type, the first PDU session is also associated with the second RAT type.

[0212] As shown in FIG7 , a flow chart is provided, including:

[0213] Step 700: The first terminal sends a ninth registration request to the AMF network element through the first RAT type access network device, and the AMF network element receives the ninth registration request from the first terminal through the first RAT type access network device.

[0214] Step 710: The AMF network element sends a ninth registration response to the first terminal via the access network device of the first RAT type, and the first terminal receives the ninth registration response from the first terminal via the access network device of the first RAT type. Optionally, the ninth registration response includes a first RA corresponding to the first RAT type.

[0215] Optionally, when the ninth registration request includes the capability information that the first terminal supports accessing the network through two access network devices, the AMF network element allocates the corresponding first RA for the first RAT type; if the ninth registration request does not include the capability information that the first terminal supports accessing the network through two access network devices of 3GPP access types, the AMF network element allocates the corresponding first RA for the 3GPP access type, but the first RAT type is not associated with the first RA.

[0216] Optionally, when the first terminal registers with the AMF network element only through the access network device of the first RAT type, the AMF network element allocates the corresponding first RA for the 3GPP access type, but the first RAT type is not associated with the first RA.

[0217] Optionally, the AMF network element obtains from the PCF network element or the UDM network element whether the first terminal is authorized to access the network through two access network devices of 3GPP access types. If the first terminal is authorized to access the network through two access network devices, the AMF network element allocates a corresponding first RA for the first RAT type; if the first terminal is not authorized to access the network through two access network devices, the AMF network element allocates a corresponding registration area for the 3GPP access type.

[0218] Optionally, at this time, the first terminal maintained by the AMF network element is in a connected state in the first RAT type.

[0219] Step 720: The first terminal sends the tenth registration request to the AMF network element through the access network device of the second RAT type, and the AMF network element receives the tenth registration request from the first terminal through the access network device of the second RAT type.

[0220] Optionally, when the first terminal sends a registration request to the AMF network element through the access network device of the first RAT type (step 700), the AMF network element allocates a first RA corresponding to the 3GPP access type. When the first terminal sends a registration request to the AMF network element through the access network device of the second RAT type (step 720), the AMF network element allocates a second RA corresponding to the second RAT type and establishes an association between the first RAT type and the first RA.

[0221] It should be noted that, when the first terminal is in dual connection mode or wishes to access the network through dual connection, step 720 is executed.

[0222] Step 730: The AMF network element sends a tenth registration response to the first terminal via the access network device of the second RAT type, and the first terminal receives the tenth registration response from the AMF network element via the access network device of the second RAT type. Optionally, the tenth registration response includes a second RA corresponding to the second RAT type.

[0223] In a possible implementation, the ninth registration request and the tenth registration request may be registration request messages, and the ninth registration response and the tenth registration response may be registration accept messages.

[0224] Optionally, at this time, the first terminal maintained by the AMF network element is in a connected state in the second RAT type.

[0225] Step 740: The first terminal establishes a first PDU session through an access network device of the first RAT type and an access network device of the second RAT type.

[0226] For example, the first terminal sends a PDU session establishment request message to the AMF network element through the access network device of the first RAT type, and the PDU session establishment request message includes the identifier of the first PDU session; the first terminal then sends a PDU session establishment request message to the AMF network element through the access network device of the second RAT type, and the PDU session establishment request message includes the identifier of the first PDU session. The first terminal stores the association relationship between the first PDU session and the first RAT type and the second RAT type.

[0227] For example, data of the first PDU session is transmitted through an access network device of the first RAT type and an access network device of the second RAT type. The AMF network element and the first terminal store the association relationship between the first PDU session and the first RAT type and the second RAT type. Optionally, the AMF network element may also send the association relationship between the first PDU session and the first RAT type and the second RAT type to the SMF network element, and the SMF network element stores the association relationship between the first PDU session and the first RAT type and the second RAT type.

[0228] Step 760: When the SMF network element receives the downlink data notification of the first PDU session from the UPF network element, the SMF network element sends a first message to the AMF network element, and the AMF network element receives the first message from the SMF network element.

[0229] Optionally, the first message may be an N1N2 message transfer message. The first message includes an identifier of the first PDU session. Further, optionally, the first message also includes indication information of a 3GPP access type.

[0230] In one possible implementation, the first PDU session is associated with the first RAT type and the second RAT type. The SMF network element selects the first RAT type from the first RAT type and the second RAT type, and the first message also includes indication information of the first RAT type. This enables the AMF network element to page the first terminal through the access network device of the selected first RAT type. Optionally, for the implementation of the SMF network element selecting one RAT type from the two RAT types, please refer to the description of the AMF network element selecting the RAT type. It can be understood that in the description of this application, the RAT type selected by the SMF network element is taken as the first RAT type for example.

[0231] Step 770: The AMF network element determines the first RAT type between the first RAT type and the second RAT type.

[0232] In one possible implementation, the first PDU session is associated with the first RAT type and the second RAT type. The AMF network element selects the first RAT type from the first RAT type and the second RAT type. The AMF network element pages the first terminal through the access network device of the selected RAT type. For example, the first RAT type and the second RAT type are 5G RAT and 6G RAT, respectively. If 5G RAT has better coverage than 6G RAT, the AMF network element preferentially selects 5G RAT to page the first terminal. For example, the first RAT type and the second RAT type are 5G NR and satellite 5G NR, respectively. 5G NR has lower latency than satellite 5G NR, so the AMF network element preferentially selects 5G NR to page the first terminal. It can be understood that in the description of this application, the RAT type selected by the AMF network element is described as the first RAT type.

[0233] In another possible implementation, the SMF network element selects a RAT type from the first RAT type and the second RAT type. The SMF network element notifies the AMF network element of the selected RAT type. For example, the first message in step 760 above may also include information indicating the RAT type selected by the SMF. It can be seen that the AMF network element may not perform step 770; step 770 is optional.

[0234] It is understood that in step 770 and the following description, the RAT type selected by the AMF network element is the first RAT type. It is understood that the RAT type selected by the AMF network element may also be a second RAT type, and the AMF network element may page the first terminal through the access network device corresponding to the second RAT type.

[0235] In one possible implementation, when the first terminal maintained by the AMF network element is in an idle state in both the first RAT type and the second RAT type, the first terminal is disconnected from the access network device of the first RAT type and the access network device of the second RAT type. The AMF network element executes step 780 to page the first terminal through the access network device of the first RAT type, thereby restoring the communication connection of the first PDU session.

[0236] Step 780: The AMF network element sends a first paging message to a first access network device corresponding to the first RAT type. The first access network device corresponding to the first RAT type receives the first paging message from the AMF network element. The first paging message includes the first identifier of the first terminal. Optionally, the first paging message may be an NGAP paging message.

[0237] In one possible implementation, the AMF network element may determine the first RA based on the stored correspondence between the first RAT type and the first RA; the AMF network element may determine the first access network device corresponding to the first RAT type based on the first RA. The first access network device is located in the first RA, and the first access network device may be one or more access network devices. Optionally, the first paging message also includes indication information of a dual connection, and the dual connection includes connections corresponding to the first RAT type and the second RAT type. The indication information of the dual connection may be referred to as a dual access indication. Alternatively, the first paging message also includes indication information of the first RAT type and the second RAT type.

[0238] Step 790: The first access network device corresponding to the first RAT type sends a third paging message, and the first terminal receives the third paging message through the first access network device corresponding to the first RAT type. The third paging message includes the first identifier of the first terminal.

[0239] Optionally, the third paging message also includes dual connection indication information, or the third paging message also includes first RAT type and second RAT type indication information. Optionally, the dual connection indication information is used to instruct the first terminal to restore or establish a connection with the access network device of the first RAT type and the access network device of the second RAT type, and the connection may refer to an RRC connection. For example, when the first terminal receives the third paging message, based on the dual connection indication information, or the first RAT type and second RAT type indication information, it can be learned that the first terminal needs to restore two connections of the first RAT type and the second RAT type, or that the first terminal needs to restore the PDU session established on the access network devices corresponding to the first RAT type and the second RAT type.

[0240] In steps 780 and 790, the AMF network element pages the first terminal through the first access network device corresponding to the first RAT type. If the AMF network element does not receive a response from the first terminal, the AMF network element may continue to page the first terminal through the access network device of the second RAT type. For example, the AMF network element sends a first paging message to the access network device of the second RAT type, and the access network device of the second RAT type receives the first paging message from the AMF network element. The access network device of the second RAT type then sends a third paging message to the first terminal.

[0241] Step 7010: The first terminal determines the first RAT type and the second RAT type according to the third paging message.

[0242] For example, the first terminal may determine the first RAT type and the second RAT type based on the dual connectivity indication information included in the third paging message. Alternatively, the first terminal may determine the first RAT type and the second RAT type based on the first RAT type and the second RAT type indication information included in the third paging message.

[0243] In one possible implementation, a first terminal determines a second cell based on a first RAT type, where the second cell is provided by a third access network device corresponding to the first RAT type. The first terminal establishes an RRC connection with the third access network device corresponding to the first RAT type. The first terminal determines a third cell based on a second RAT type, where the third cell is provided by a fourth access network device corresponding to the second RAT type. The first terminal establishes an RRC connection with the fourth access network device corresponding to the second RAT type.

[0244] In a possible implementation, the first terminal may determine the first PDU session according to the association relationship between the first PDU session and the first RAT type and the second RAT type stored in step 740 .

[0245] Step 7011: The first terminal sends a third message to the AMF network element through the third access network device corresponding to the first RAT type and the fourth access network device corresponding to the second RAT type. The AMF network element receives the third message from the first terminal through the third access network device of the first RAT type and the fourth access network device of the second RAT type. The third message includes the identifier of the first PDU session, and the third message is used to request to restore the communication connection of the first PDU session.

[0246] For example, the first terminal sends a third message to the AMF network element through the third access network device of the first RAT type, and the AMF network element receives the third message from the first terminal through the third access network device of the first RAT type. The first terminal sends a third message to the AMF network element through the fourth access network device of the second RAT type, and the AMF network element receives the third message from the first terminal through the fourth access network device of the second RAT type, etc. Optionally, the third message may be a service request message. The AMF network element may request the SMF network element to restore the communication connection of the first PDU session, specifically, to restore the communication connection of the first PDU session in the first RAT type and the communication connection of the first PDU session in the second RAT type, etc.

[0247] It can be understood that the solution of establishing a PDU session through access network devices of two RAT types in Example 4 can also be applied to Example 2 or Example 3. For example, when applied to the solution in Example 2, the AMF network element allocates an identifier of the first terminal corresponding to the first RAT type, and the AMF network element allocates an identifier of the first terminal corresponding to the second RAT type. The difference is that the paging messages in steps 780 and 790 may carry two identifiers of the first terminal, for example, the identifier of the first terminal corresponding to the first RAT type and the identifier of the first terminal corresponding to the second RAT type, etc. When the first terminal receives the paging message, it can restore the communication connection of the first PDU session associated with the first RAT type and the second RAT type.

[0248] Through the above method, when a PDU session is established through access network devices of two RAT types, one RAT type can be selected from the two RAT types to page the first terminal. Upon receiving the paging message, the first terminal can restore the communication connection of the first PDU session across the two RAT types based on the information carried in the paging message (e.g., dual connectivity indication information, etc.).

[0249] An embodiment of the present application further provides a paging method, including: when a terminal registers or accesses an AMF network element through access network devices of two RAT types, the AMF network element negotiates with a second terminal the RAT type for paging the second terminal. The AMF network element pages the second terminal through the access network device corresponding to the negotiated RAT type.

[0250] As shown in FIG8 , a flow chart is provided, including:

[0251] Step 800: The second terminal sends a fifth registration request to the AMF network element through the access network device of the third RAT type, and the AMF network element receives the fifth registration request from the second terminal through the access network device of the third RAT type.

[0252] For example, when the AMF network element receives the fifth registration request, the AMF network element allocates a corresponding third RA for the third RAT type, and the AMF network element stores the association relationship between the third RAT type and the third RA.

[0253] Optionally, when the fifth registration request includes the capability information that the second terminal supports accessing the network through two access network devices, the AMF network element allocates a corresponding third RA for the third RAT type; if the fifth registration request does not include the capability information that the second terminal supports accessing the network through two access network devices of 3GPP access types, the AMF network element allocates a corresponding third RA for the 3GPP access type, but the third RAT type is not associated with the third RA.

[0254] Optionally, when the second terminal registers with the AMF network element only through the access network device of the third RAT type, the AMF network element allocates the corresponding third RA for the 3GPP access type, but the third RAT type is not associated with the third RA.

[0255] Optionally, the AMF network element obtains from the PCF network element or the UDM network element whether the second terminal is authorized to access the network through two access network devices of 3GPP access types. If the second terminal is authorized to access the network through two access network devices, the AMF network element allocates a corresponding third RA for the third RAT type; if the second terminal is not authorized to access the network through two access network devices, the AMF network element allocates a corresponding registration area for the 3GPP access type.

[0256] Step 810: The AMF network element sends a fifth registration response to the second terminal via the access network device of the third RAT type, and the second terminal receives the fifth registration response from the AMF network element via the access network device of the third RAT type. Optionally, the fifth registration response includes a third RA associated with the third RAT type.

[0257] For example, the second terminal obtains the third RA associated with the third RAT type in the fifth registration response, and the second terminal stores the association relationship between the third RAT type and the third RA.

[0258] Optionally, at this time, the second terminal maintained by the AMF network element is in a connected state in the third RAT type.

[0259] Step 820: The second terminal sends a sixth registration request to the AMF network element through the access network device of the fourth RAT type, and the AMF network element receives the sixth registration request from the second terminal through the access network device of the fourth RAT type.

[0260] For example, when the AMF network element receives the sixth registration request, the AMF network element allocates the corresponding fourth RA for the fourth RAT type, and the AMF network element stores the association relationship between the fourth RAT type and the fourth RA.

[0261] Optionally, when the second terminal sends a registration request to the AMF network element through the access network device of the third RAT type (step 800), the AMF network element allocates a third RA corresponding to the 3GPP access type. When the second terminal sends a registration request to the AMF network element through the access network device of the fourth RAT type (step 820), the AMF network element allocates a fourth RA corresponding to the fourth RAT type and establishes an association between the third RAT type and the third RA.

[0262] It should be noted that, when the second terminal is in dual connection mode or wishes to access the network through dual connection, step 820 is executed.

[0263] Step 830: The AMF network element sends a sixth registration response to the second terminal via the access network device of the fourth RAT type, and the second terminal receives the sixth registration response from the AMF network element via the access network device of the fourth RAT type. Optionally, the sixth registration response includes a fourth RA associated with the fourth RAT type.

[0264] For example, the second terminal obtains the fourth RA associated with the fourth RAT type in the sixth registration response, and the second terminal stores the association relationship between the fourth RAT type and the fourth RA.

[0265] Optionally, the fifth registration request and the sixth registration request may be registration request messages, and the fifth registration response and the sixth registration response may be registration accept messages.

[0266] Optionally, at this time, the second terminal maintained by the AMF network element is in a connected state in the fourth RAT type.

[0267] In one possible implementation, the AMF network element and the second terminal may negotiate a target RAT type for paging the second terminal, that is, the target RAT type is used for paging the second terminal. The target RAT type is the third RAT type or the fourth RAT type.

[0268] In one possible implementation, the target RAT type is determined by the second terminal. For example, the second terminal sends a fifth message to the AMF network element, and the AMF network element receives the fifth message from the second terminal. The fifth message includes information indicating the target RAT type. Optionally, the fifth message may be a fifth registration request or a sixth registration request from the second terminal. For example, the fifth registration request or the sixth registration request may include information indicating the target RAT type.

[0269] In another possible implementation, the target RAT type is determined by the AMF network element. For example, the AMF network element sends a sixth message to the second terminal, and the second terminal receives the sixth message from the AMF network element. The sixth message includes information indicating the target RAT type. Optionally, the sixth message may be a fifth registration response or a sixth registration response from the second terminal. For example, the fifth registration response or the sixth registration response includes information indicating the target RAT type.

[0270] In another possible implementation, the target RAT type is requested by the second terminal and determined by the AMF network element. For example, the second terminal sends a fifth message to the AMF network element, and the AMF network element receives the fifth message from the second terminal. The fifth message includes information indicating the target RAT type requested by the second terminal. Optionally, the fifth message may be a fifth registration request or a sixth registration request from the second terminal. The AMF network element sends a sixth message to the second terminal, and the second terminal receives the sixth message from the AMF network element. The sixth message includes information indicating the determined target RAT type. Optionally, the sixth message may be a fifth registration response or a sixth registration response from the second terminal. The information indicating the target RAT type requested by the second terminal and the information indicating the target RAT type determined by the AMF network element may be the same as or different from each other.

[0271] Step 840: The second terminal establishes a second session through an access network device of the third RAT type.

[0272] Optionally, the second session may be a second PDU session. In the following description and the flowchart of Figure 8, the second PDU session is used as an example. For example, the second PDU session is associated with a third RAT type. The AMF network element and the second terminal may store the association relationship between the second PDU session and the third RAT type. Optionally, the AMF network element may send the association relationship between the second PDU session and the third RAT type to the SMF network element. The SMF network element stores the association relationship between the second PDU session and the third RAT type.

[0273] Steps 800 to 840 are optional.

[0274] Step 860: When the SMF network element receives the downlink data notification of the second PDU session from the UPF network element, the SMF network element sends a fourth message to the AMF network element, and the AMF network element receives the fourth message from the SMF network element.

[0275] Among them, the fourth message includes an identifier of the second PDU session. Optionally, the fourth message also includes indication information of the third RAT type. Further, optionally, the fourth message also includes indication information of the 3GPP access type. The second terminal registers (or connects) to the AMF network element through an access network device of the third RAT type and an access network device of the fourth RAT type. The second PDU session is associated with the third RAT type. For example, the second terminal establishes a second PDU session through an access network device corresponding to the third RAT type, or the second PDU session is established on an access network device of the third RAT type, etc. Optionally, the fourth message may be an N1N2 message transfer message.

[0276] In one possible implementation, the AMF network element may maintain the status of the second terminal corresponding to the third RAT type and the fourth RAT type. For example, in step 840, the connection between the second terminal and the access network device of the third RAT type is disconnected, so the status of the second terminal maintained by the AMF network element in the third RAT type is idle. The second PDU session is established through the access network device corresponding to the third RAT type, so the communication of the second PDU session of the second terminal is interrupted. At this time, it is necessary to restore the communication connection of the second PDU session so as to realize the transmission of the corresponding downlink data using the second PDU session. The status of the second terminal maintained by the AMF network element in the fourth RAT type can be a connected state or an idle state.

[0277] In this example, steps 870a, 880a, and 890 can be directly executed. Alternatively, steps 870a, 880a, and 890 can be executed when certain conditions are met. In the following description, steps 870a, 880a, and 890 are executed when the conditions of Case 1 are met as an example.

[0278] Case 1: The second terminal is disconnected from both the third RAT type access network device and the fourth RAT type access network device. Optionally, at this point, the second terminal maintained by the AMF network element is in an idle state for both the third RAT type and the fourth RAT type. For Case 1, execute steps 870a and 880a.

[0279] In one possible implementation, since the second PDU session is established through an access network device of the third RAT type, when the connection between the second terminal and the access network device of the third RAT type is disconnected, the communication of the second PDU session is also interrupted. In step 870a, the AMF network element pages the second terminal through the target access network device corresponding to the negotiated target RAT type, thereby restoring or establishing the connection between the second terminal and the access network device of the third RAT type, thereby restoring the communication connection of the second PDU session.

[0280] Step 870a: The AMF network element sends a fourth paging message to the target access network device corresponding to the target RAT type, and the target access network device corresponding to the target RAT type receives the fourth paging message from the AMF network element. The fourth paging message includes the identifier of the second terminal.

[0281] The target access network device is in the RA corresponding to the target RAT type. For example, when the target RAT type is a third RAT type, the target access network device is in a third RA corresponding to the third RAT type. Alternatively, when the target RAT type is a fourth RAT type, the target access network device is in a fourth RA corresponding to the fourth RAT type. Optionally, the fourth paging message may be an NGAP paging message.

[0282] In one possible implementation, when the AMF network element receives the fourth message, it obtains the identifier of the second PDU session in the fourth message. The AMF network element determines the third RAT type based on the stored association between the second PDU session and the third RAT type. When the target RAT type negotiated between the AMF network element and the second terminal is the third RAT type, the AMF network element sends a fourth paging message to the access network device of the third RAT type. In step 880a, the access network device of the third RAT type sends a fifth paging message, and the second terminal receives the fifth paging message. Alternatively, when the target RAT type negotiated between the AMF network element and the second terminal is the fourth RAT type, the AMF network element sends a fourth paging message to the access network device of the fourth RAT type, and the fourth paging message also includes indication information of the third RAT type. In step 880a, the access network device of the fourth RAT type sends a fifth paging message, and the fifth paging message also includes indication information of the third RAT type. The second terminal receives the fifth paging message, and according to the indication information of the third RAT type included in the fifth paging message, the second terminal restores the RRC connection with the access network device of the third RAT type, and further requests to restore the communication connection of the second PDU session associated with the third RAT type.

[0283] Step 880a: The target access network device corresponding to the target RAT type sends a fifth paging message, and the second terminal receives the fifth paging message through the target access network device corresponding to the target RAT type. The fifth paging message includes an identifier of the second terminal.

[0284] Optionally, the second terminal may receive the fifth paging message based on the target RAT type. For example, different RAT types may use different radio resources to transmit paging messages. The third RAT type corresponds to the third radio resource, and the fourth RAT type corresponds to the fourth radio resource. When the target RAT type negotiated between the AMF network element and the second terminal is the third RAT type, the second terminal receives the fifth paging message on the third radio resource. Alternatively, when the target RAT type negotiated between the AMF network element and the second terminal is the fourth RAT type, the second terminal receives the fifth paging message on the fourth radio resource.

[0285] In one possible implementation, when the target RAT type is the third RAT type, when the second terminal receives the fifth paging message through the access network device corresponding to the third RAT type, the second terminal determines the second PDU session based on the stored association between the second PDU session and the third RAT type. The second terminal requests, in step 890, to restore the communication connection of the second PDU session.

[0286] In another possible implementation, when the target RAT type is the fourth RAT type, the second terminal receives a fifth paging message via the access network device corresponding to the fourth RAT type. The fifth paging message also includes information indicating the third RAT type. The second terminal determines the third RAT type based on the information indicating the third RAT type included in the fifth paging message. The second terminal determines the second PDU session based on the stored information indicating the second PDU session and the third RAT type. In step 890, the second terminal requests to restore the communication connection of the second PDU session.

[0287] Case 2: The second terminal is disconnected from the access network device of the third RAT type, while the second terminal remains connected to the access network device of the fourth RAT type. Optionally, at this time, the second terminal maintained by the AMF network element is in an idle state for the third RAT type, while the second terminal maintained by the AMF network element is in a connected state for the fourth RAT type. For Case 2, execute step 870b.

[0288] Step 870b: The AMF network element sends a NAS notification message to the second terminal through the access network device of the fourth RAT type. The second terminal receives the NAS notification message from the AMF network element through the access network device of the fourth RAT type. The NAS notification message includes indication information of the third RAT type.

[0289] It is understandable that in the scenario of Case 2, the AMF network element can also use the solution in the aforementioned Case 1 (for example, steps 870a and 880a) to page the second terminal without restriction.

[0290] It can be understood that, in the process of Figure 8, it is set that the second PDU session is associated with the third RAT type. If the second PDU session is associated with the fourth RAT type. Situation 3 exists: when the connection between the second terminal and the access network device of the fourth RAT type is disconnected, and the second terminal remains connected to the access network device of the third RAT type, the AMF network element can send a NAS notification message to the second terminal through the access network device of the third RAT type, and the second terminal can receive the NAS notification message from the AMF network element through the access network device of the third RAT type, and the NAS notification message includes indication information of the fourth RAT type.

[0291] Step 890: The second terminal sends a seventh message to the AMF network element through the access network device corresponding to the third RAT type. The seventh message includes the identifier of the second PDU session corresponding to the third RAT type. The seventh message is used to request the restoration of the communication connection of the second PDU session.

[0292] In one possible implementation, before the second terminal sends the seventh message to the AMF network element via the access network device of the third RAT type, the second terminal restores the RRC connection with the access network device of the third RAT type. For example, the second terminal determines a fourth cell based on the third RAT type, where the fourth cell is provided by the access network device corresponding to the third RAT type. The second terminal restores the RRC connection with the access network device corresponding to the third RAT type. Optionally, the seventh message may be a service request message.

[0293] It can be understood that in the flowchart of Figure 8, the target RAT type negotiated between the AMF network element and the second terminal is the third RAT type as an example.

[0294] Through the above method, the AMF network element negotiates with the second terminal on the RAT type used to paging the second terminal. The second terminal listens to the paging message under the negotiated RAT type, thereby saving the terminal's listening energy consumption. "Listening" can be understood as receiving. For example, the AMF network element negotiates with the second terminal to page the second terminal under the third RAT type. The AMF network element sends a fourth paging message to the access network device of the third RAT type, and the access network device of the third RAT type sends a fifth paging message to the second terminal. The second terminal listens to the paging message under the access network device of the third RAT type. By listening to the paging message only under a specific RAT type, the terminal's listening energy consumption is saved.

[0295] It is understood that in the embodiments of the present application:

[0296] 1. In addition to focusing on describing the differences between different processes, the descriptions of different processes can refer to each other.

[0297] 2. In each process, the order of different steps is not limited. In addition, each process may include fewer steps or more steps than the flowchart or text description.

[0298] 3. In the processes of Figures 3 to 8, the description is made by taking the terminal, access network equipment, AMF network element, or SMF network element as the execution subject. It can be understood that in each process, the function of the terminal can be implemented by the terminal, or by a module in the terminal (such as a chip or circuit, etc.). The function of the access network device can be implemented by the access network device, or by a module in the access network device (such as a chip or circuit, etc.), or by a logical node, logical module or software that can fully or partially implement the function of the access network device. The function of the AMF network element or SMF network element can be implemented by the AMF network element or SMF network element, or by a module in the AMF network element or SMF network element (such as a chip or circuit, etc.).

[0299] 4. In the embodiments of the present application, "(e.g., a terminal) receives information from (e.g., an access network device)" can be understood to mean that the source of the information is the access network device and the destination is the terminal, which may include the terminal directly or indirectly receiving information from the access network device. The information may undergo necessary processing between the source and destination, such as format changes, but the destination can still understand the valid information from the source. Similar expressions in this application should be understood similarly and will not be repeated here.

[0300] In the embodiments provided by the present application above, the methods provided by the embodiments of the present application are introduced from the perspective of the interaction between the terminal, access network equipment, AMF network element and SMF network element. In order to realize the various functions in the methods provided by the embodiments of the present application, the terminal, access network equipment, AMF network element or SMF network element, etc. may include hardware structure and / or software module, and realize the above functions in the form of hardware structure, software module, or hardware structure plus software module. Whether a certain function among the above functions is executed in the form of hardware structure, software module, or hardware structure plus software module depends on the design constraints of the specific application of the technical solution.

[0301] Figures 9 and 10 are schematic diagrams of the structures of possible communication devices provided in the embodiments of the present application. These communication devices can implement one or more corresponding functions in the above-mentioned method embodiments. For example, the functions implemented by the AMF network element or terminal, etc., may therefore achieve the beneficial effects of the above-mentioned method embodiments. In the embodiment of the present application, the communication device may be the terminal 100 shown in Figure 1, the access network device in RAN200, or the AMF network element in the core network 300, or a module (such as a chip) applied to the terminal, access network device or AMF network element.

[0302] As shown in Figure 9, the communication device 900 includes a processing unit 910 and a transceiver unit 920. The communication device 900 is used to implement the functions of the AMF network element or terminal in any of the method embodiments shown in Figures 3 to 8 above.

[0303] Optionally, the transceiver unit 920 may also be referred to as an output unit, an interface unit, or a communication unit. In one possible implementation, the transceiver unit 920 includes at least one of a transmitting unit and a receiving unit. The transmitting unit and the receiving unit may be integrated together or may be two independent units.

[0304] When the communication device 900 is used to implement the functions of the AMF network element in Figures 3 to 7, specifically:

[0305] The transceiver unit 920 is used to receive a first message from a session management function network element, where the first message includes an identifier of a first session of a first terminal, the first session is associated with a first radio access technology type, and the first terminal is registered with the access and mobility management function network element through an access network device of the first radio access technology type and an access network device of a second radio access technology type; the processing unit 910 is used to generate a first paging message; the transceiver unit 920 is also used to send a first paging message to a first access network device corresponding to the first radio access technology type, where the first paging message includes a first identifier of the first terminal.

[0306] In one possible design, the first access network device is in a first registration area corresponding to the first wireless access technology type.

[0307] In one possible design, the transceiver unit 920 is also used to receive a first registration request from the first terminal, and the first registration request is received through an access network device of the first wireless access technology type; the transceiver unit 920 is also used to send a first registration response to the first terminal, and the first registration response includes a first registration area corresponding to the first wireless access technology type.

[0308] In one possible design, the processing unit 910 is further used to store the association between the first wireless access technology type and the first registration area.

[0309] In one possible design, the transceiver unit 920 is also used to receive a second registration request from the first terminal, and the second registration request is received through an access network device of the second wireless access technology type; the transceiver unit 920 is also used to send a second registration response to the first terminal, and the second registration response includes a second registration area corresponding to the second wireless access technology type.

[0310] In one possible design, the processing unit 910 is further used to store the association between the second wireless access technology type and the second registration area.

[0311] In one possible design, the processing unit 910 is further used to determine the first identifier of the first terminal based on the first wireless access technology type.

[0312] In one possible design, the transceiver unit 920 is also used to receive a third registration request from the first terminal, and the third registration request is received through the access network device of the first wireless access technology type; the transceiver unit 920 is also used to send a third registration response to the first terminal, and the third registration response includes the second identifier of the first terminal corresponding to the first wireless access technology type, and the second identifier includes the first identifier.

[0313] In one possible design, the processing unit 910 is further used to store the association relationship between the second identifier and the first wireless access technology type, or to store the association relationship between the first identifier and the first wireless access technology type.

[0314] In one possible design, the transceiver unit 920 is also used to receive a fourth registration request from the first terminal, and the fourth registration request is received through the access network device of the second wireless access technology type; the transceiver unit 920 is also used to send a fourth registration response to the first terminal, and the fourth registration response includes the third identifier of the first terminal corresponding to the second wireless access technology type, and the third identifier includes the fourth identifier of the first terminal.

[0315] In one possible design, the processing unit 910 is further used to store the association relationship between the third identifier and the second wireless access technology type, or to store the association relationship between the fourth identifier and the second wireless access technology type.

[0316] In one possible design, the connection state of the first terminal corresponding to the first wireless access technology type is an idle state.

[0317] In one possible design, the processing unit 910 is further used to determine the first radio access technology type associated with the first session based on an association relationship between the session and the radio access technology type.

[0318] In one possible design, the first paging message also includes indication information of the first radio access technology type.

[0319] In a possible design, the first session is also associated with a second radio access technology type, and the processing unit 910 is further used to determine the first radio access technology type between the first radio access technology type and the second radio access technology type.

[0320] In one possible design, the first paging message also includes indication information of a dual connection, where the dual connection includes connections corresponding to the first radio access technology type and the second radio access technology type, or the first paging message also includes indication information of the first radio access technology type and the second radio access technology type.

[0321] When the communication device 900 is used to implement the functions of the terminal in FIG. 4 , FIG. 5 and FIG. 6 , specifically:

[0322] The transceiver unit 920 is used to receive a second paging message, which is received through the first access network device corresponding to the first wireless access technology type. The second paging message includes the first identifier of the first terminal, and the first terminal is registered to the access and mobility management function network element through the access network device of the first wireless access technology type and the access network device of the second wireless access technology type; the processing unit 910 is used to determine the first wireless access technology type based on the second paging message or the first identifier; the transceiver unit 920 is also used to send a second message to the access and mobility management function network element through the second access network device corresponding to the first wireless access technology type, where the second message includes the identifier of the first session associated with the first wireless access technology type, and the second message is used to request to restore the communication connection of the first session.

[0323] In one possible design, the first access network device is in a first registration area corresponding to the first wireless access technology type.

[0324] In one possible design, the transceiver unit 920 is also used to send a first registration request to the access and mobility management function network element, and the first registration request is sent through the access network device of the first wireless access technology type; the transceiver unit 920 is also used to receive a first registration response from the access and mobility management function network element, and the first registration response includes a first registration area corresponding to the first wireless access technology type.

[0325] In one possible design, the processing unit 910 is further used to store an association between the first radio access technology type and the first registration area.

[0326] In one possible design, the transceiver unit 920 is also used to send a second registration request to the access and mobility management function network element, and the second registration request is sent through the access network device of the second wireless access technology type; the transceiver unit 920 is also used to receive a second registration response from the access and mobility management function network element, and the second registration response includes a second registration area of ​​the second wireless access technology type.

[0327] In one possible design, the processing unit 910 is further used to store an association between the second radio access technology type and the second registration area.

[0328] In one possible design, when the processing unit 910 determines the first wireless access technology type based on the second paging message, it includes: determining the first wireless access technology type based on the indication information of the first wireless access technology type included in the second paging message; or, determining the first wireless access technology type based on the wireless resources for receiving the second paging message.

[0329] In one possible design, the transceiver unit 920 is also used to send a third registration request to the access and mobility management function network element, and the third registration request is sent through the access network device of the first wireless access technology type; the transceiver unit 920 is also used to receive a third registration response from the access and mobility management function network element, and the third registration response includes the second identifier of the first terminal of the first wireless access technology type, and the second identifier includes the first identifier.

[0330] In one possible design, the processing unit 910 is further used to store the association relationship between the second identifier and the first wireless access technology type, or to store the association relationship between the first identifier and the first wireless access technology type.

[0331] In one possible design, the transceiver unit 920 is also used to send a fourth registration request to the access and mobility management function network element, and the fourth registration request is sent through the access network device of the second wireless access technology type; the transceiver unit 920 is also used to receive a fourth registration response from the access and mobility management function network element, and the fourth registration response includes the third identifier of the first terminal of the second wireless access technology type, and the third identifier includes the fourth identifier of the first terminal.

[0332] In one possible design, the processing unit 910 is further used to store the association relationship between the third identifier and the second wireless access technology type, or to store the association relationship between the fourth identifier and the second wireless access technology type.

[0333] In one possible design, the processing unit 910 is further used to determine a first cell based on the first wireless access technology type, where the first cell is a cell provided by the second access network device.

[0334] In one possible design, the connection state of the first terminal corresponding to the first wireless access technology type is an idle state.

[0335] When the communication device 900 is used to implement the functions of the terminal in the process of FIG7 , specifically:

[0336] The transceiver unit 920 is used to receive a third paging message, which is received through the first access network device corresponding to the first radio access technology type. The third paging message includes the first identifier of the first terminal, and the first terminal is registered to the access and mobility management function network element through the access network device of the first radio access technology type and the access network device of the second radio access technology type; the processing unit 910 is used to determine the first radio access technology type and the second radio access technology type according to the third paging message; the transceiver unit 920 is also used to send a third message to the access and mobility management function network element through the third access network device corresponding to the first radio access technology type and the fourth access network device corresponding to the second radio access technology type, the third message including the identifier of the first session associated with the first radio access technology type and the second radio access technology type, and the third message is used to request to restore the communication connection of the first session.

[0337] In one possible design, the third paging message also includes indication information of a dual connection, where the dual connection includes connections corresponding to the first radio access technology type and the second radio access technology type, or the third paging message also includes indication information of the first radio access technology type and the second radio access technology type.

[0338] In one possible design, the processing unit 910 is also used to determine a second cell based on the first wireless access technology type, where the second cell is a cell provided by a third access network device corresponding to the first wireless access technology type; and to determine a third cell based on the second wireless access technology type, where the third cell is a cell provided by a fourth access network device corresponding to the second wireless access technology type.

[0339] In one possible design, the connection state of the first terminal corresponding to the first wireless access technology type is an idle state.

[0340] When the communication device 900 is used to implement the functions of the AMF network element in FIG8 , specifically:

[0341] The transceiver unit 920 is configured to receive a fourth message from the session management function network element, the fourth message including an identifier of a second session of a second terminal, the second session being associated with a third radio access technology type, and the second terminal being registered with the access and mobility management function network element via an access network device of the third radio access technology type and an access network device of a fourth radio access technology type; the processing unit 910 is configured to generate a fourth paging message. The transceiver unit 920 is further configured to send a fourth paging message to a target access network device corresponding to a target radio access technology type, the fourth paging message including an identifier of the second terminal, the target radio access technology type being determined by the second terminal or the access and mobility management function network element, and the target radio access technology type being the third radio access technology type or the fourth radio access technology type.

[0342] In one possible design, the target access network device is in the registration area corresponding to the target wireless access technology type.

[0343] In one possible design, the target wireless access technology type is the third wireless access technology type, and the transceiver unit 920 is also used to receive a fifth registration request from the second terminal, and the fifth registration request is received through the access network device of the third wireless access technology type; the transceiver unit 920 is also used to send a fifth registration response to the second terminal, and the fifth registration response includes a third registration area associated with the third wireless access technology type.

[0344] In one possible design, the processing unit 910 is further used to store the association between the third wireless access technology type and the third registration area.

[0345] In one possible design, the target wireless access technology type is the fourth wireless access technology type, and the transceiver unit 920 is further used to receive a sixth registration request from the second terminal, and the sixth registration request is received through the access network device of the fourth wireless access technology type; the transceiver unit 920 is also used to send a sixth registration response to the second terminal, and the sixth registration response includes a fourth registration area associated with the fourth wireless access technology type.

[0346] In one possible design, the processing unit 910 is further used to store the association between the fourth wireless access technology type and the fourth registration area.

[0347] In one possible design, the target wireless access technology type is determined by the second terminal, and the transceiver unit 920 is also used to receive a fifth message from the second terminal, where the fifth message includes indication information of the target wireless access technology type.

[0348] In one possible design, the target wireless access technology type is determined by the access and mobility management function network element, and the transceiver unit 920 is also used for the second terminal to send a sixth message, and the sixth message includes indication information of the target wireless access technology type.

[0349] In one possible design, the target wireless access technology type is the fourth wireless access technology type, and the fourth paging message also includes indication information of the third wireless access technology type.

[0350] In one possible design, the state of the second terminal corresponding to the third wireless access technology type is an idle state.

[0351] When the communication device 900 is used to implement the functions of the terminal in the process of FIG8 , specifically:

[0352] The transceiver unit 920 is configured to receive a fifth paging message, where the fifth paging message is received through a target access network device corresponding to a target radio access technology type, the fifth paging message including an identifier of the second terminal, the target radio access technology type being determined by the second terminal or the access and mobility management function network element, the second terminal registering with the access and mobility management function network element through an access network device of the third radio access technology type and an access network device of the fourth radio access technology type, the target radio access technology type being the third radio access technology type or the fourth radio access technology type; when the target radio access technology type is the fourth radio access technology type, the fifth paging message also includes indication information of the third radio access technology type; the processing unit 910 is configured to generate a seventh message; the transceiver unit 920 is further configured to send a seventh message to the access and mobility management function network element through the access network device corresponding to the third radio access technology type, the seventh message including an identifier of the second session corresponding to the third radio access technology type, the seventh message being used to request restoration of the communication connection of the second session.

[0353] In one possible design, when the transceiver unit 920 receives the fifth paging message, specifically: the processing unit 910 controls the transceiver unit 920 to receive the fifth paging message according to the target wireless access technology type.

[0354] In one possible design, the target access network device is in the registration area corresponding to the target wireless access technology type.

[0355] In one possible design, the target wireless access technology type is the third wireless access technology type, and the transceiver unit 920 is further used to send a fifth registration request to the access and mobility management function network element, and the fifth registration request is sent through the access network device of the third wireless access technology type; the transceiver unit 920 is also used to receive a fifth registration response from the access and mobility management function network element, and the fifth registration response includes a third registration area associated with the third wireless access technology type.

[0356] In one possible design, the processing unit 910 is further used to store the association between the third wireless access technology type and the third registration area.

[0357] In one possible design, the target wireless access technology type is the fourth wireless access technology type, and the transceiver unit 920 is further used to send a sixth registration request to the access and mobility management function network element, and the sixth registration request is sent through the access network device of the fourth wireless access technology type; the transceiver unit 920 is also used to receive a sixth registration response from the access and mobility management function network element, and the sixth registration response includes a fourth registration area associated with the fourth wireless access technology type.

[0358] In one possible design, the processing unit 910 is further used to store the association between the fourth wireless access technology type and the fourth registration area.

[0359] In one possible design, the target wireless access technology type is determined by the second terminal, and the transceiver unit 920 is also used to send a fifth message to the access and mobility management function network element, and the fifth message includes indication information of the target wireless access technology type.

[0360] In one possible design, the target wireless access technology type is determined by the access and mobility management function network element, and the transceiver unit 920 is also used to receive a sixth message from the access and mobility management function network element, and the sixth message includes indication information of the target wireless access technology type.

[0361] In one possible design, the processing unit 910 is further used to determine a fourth cell based on the third wireless access technology type, where the fourth cell is a cell provided by an access network device corresponding to the third wireless access technology type.

[0362] In one possible design, the state of the second terminal corresponding to the third wireless access technology type is an idle state.

[0363] For a more detailed description of the processing unit 910 and the transceiver unit 920, reference may be made to the descriptions in FIG. 3 to FIG. 8 in the above method embodiments, which will not be repeated here.

[0364] It is understood that the division of units in the embodiments of the present application is schematic and is only a logical functional division. In actual implementation, there may be other division methods. In addition, the various functional units in the embodiments of the present application can be integrated into a physical device (for example, a processor), or each functional unit can be a separate physical device, or two or more units can be integrated into a unit for implementation. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional modules.

[0365] As shown in Figure 10, communication device 1000 includes a processor 1010 and an interface circuit 1020. Processor 1010 and interface circuit 1020 are coupled to each other. It will be appreciated that interface circuit 1020 may be a transceiver or an input / output interface. Optionally, communication device 1000 may further include a memory 1030 for storing instructions executed by processor 1010, input data required by processor 1010 to execute instructions, or data generated by processor 1010 after executing instructions.

[0366] When the communication device 1000 is used to implement the methods shown in FIG. 3 to FIG. 8 , the processor 1010 is used to implement the functions of the processing unit 910 , and the interface circuit 1020 is used to implement the functions of the transceiver unit 920 .

[0367] When the communication device is a chip used in a terminal, the chip implements the terminal functions described in the method embodiments. The chip receives information sent by the access network device to the terminal through other modules in the terminal (such as a radio frequency module or antenna); alternatively, the chip sends information to other modules in the terminal (such as a radio frequency module or antenna), and the information is sent by the terminal to the access network device.

[0368] When the above-mentioned communication device is a module applied to an AMF network element, the module implements the functions of the AMF network element in the above-mentioned method embodiment. The module receives information from other modules in the AMF network element (such as a radio frequency module or antenna), and the information is sent by the terminal to the AMF network element; or the module sends information to other modules in the AMF network element (such as a radio frequency module or antenna), and the information is sent by the AMF network element to the terminal.

[0369] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0370] The memory in the embodiments of the present application can be a random access memory (RAM), a flash memory, a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a register, a hard disk, a mobile hard disk, a CD-ROM, or any other form of storage medium known in the art.

[0371] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC.

[0372] An embodiment of the present application also provides a communication device, which includes a processor and a memory, the processor and the memory are coupled, and the processor is used to implement the functions of the AMF network element or terminal in Figures 3 to 8.

[0373] An embodiment of the present application also provides a communication device, including a processor, which is used to implement the functions of the AMF network element or terminal in Figures 3 to 8.

[0374] The present application also provides a computer-readable storage medium storing instructions, which may also be referred to as a computer program, computer program code, etc. The instructions are executed on a computer, causing the computer to perform the functions of the AMF network element or terminal in Figures 3 to 8 of the above method embodiments.

[0375] An embodiment of the present application also provides a computer program product, including a computer program or instructions. When the computer program or instructions are run on a computer, the method of the AMF network element or terminal in Figures 3 to 8 is implemented.

[0376] An embodiment of the present application also provides a chip, which includes a processor, which is coupled to a memory, and the processor is used to execute a computer program or instruction stored in the memory, so that the functions of the AMF network element or terminal in Figures 3 to 8 are implemented.

[0377] The present application also provides a communication system including a first communication device and a second communication device. The first communication device and the second communication device can be used to implement the functions of the AMF network element and the terminal in Figures 3 to 8, respectively. Furthermore, the system also includes a third communication device for implementing the functions of the access network device in Figures 3 to 8.

[0378] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0379] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

Claims

1. A paging method, characterized in that: The method is applied to an access and mobility management function network element, comprising: receiving a first message from a session management function network element, the first message including an identifier of a first session of a first terminal, the first session being associated with a first radio access technology type, the first terminal being registered with the access and mobility management function network element through an access network device of the first radio access technology type and an access network device of a second radio access technology type; A first paging message is sent to a first access network device corresponding to the first wireless access technology type, where the first paging message includes a first identifier of the first terminal.

2. The method according to claim 1, characterized in that The first access network device is in a first registration area corresponding to the first wireless access technology type.

3. The method according to claim 1, characterized in that The method further comprises: Determine a first identifier of the first terminal according to the first radio access technology type.

4. The method according to claim 3, characterized in that: The method further comprises: receiving a third registration request from the first terminal, where the third registration request is received through an access network device of the first radio access technology type; A third registration response is sent to the first terminal, where the third registration response includes a second identifier of the first terminal corresponding to the first radio access technology type, and the second identifier includes the first identifier.

5. The method according to claim 4, characterized in that The method further comprises: An association relationship between the second identifier and the first radio access technology type is stored, or an association relationship between the first identifier and the first radio access technology type is stored.

6. The method according to any one of claims 1 to 5, characterized in that The connection state of the first terminal corresponding to the first radio access technology type is an idle state.

7. The method according to any one of claims 1 to 6, characterized in that The method further comprises: The first radio access technology type associated with the first session is determined according to an association relationship between the session and the radio access technology type.

8. The method according to claim 7, characterized in that The first paging message also includes indication information of the first radio access technology type.

9. The method according to any one of claims 1 to 8, characterized in that The first session is also associated with a second radio access technology type, and the method further includes: The first radio access technology type is determined between the first radio access technology type and the second radio access technology type.

10. The method according to claim 9, characterized in that The first paging message also includes indication information of dual connection, where the dual connection includes connections corresponding to the first radio access technology type and the second radio access technology type, or the first paging message also includes indication information of the first radio access technology type and the second radio access technology type.

11. A paging method, characterized in that: The method is applied to an access and mobility management function network element, comprising: receiving a fourth message from a session management function network element, the fourth message including an identifier of a second session of a second terminal, the second session being associated with a third radio access technology type, and the second terminal being registered with the access and mobility management function network element through an access network device of the third radio access technology type and an access network device of a fourth radio access technology type; A fourth paging message is sent to a target access network device corresponding to a target wireless access technology type, wherein the fourth paging message includes an identifier of the second terminal, the target wireless access technology type is determined by the second terminal or the access and mobility management function network element, and the target wireless access technology type is the third wireless access technology type or the fourth wireless access technology type.

12. The method according to claim 11, characterized in that The target access network device is in the registration area corresponding to the target wireless access technology type.

13. The method according to claim 11 or 12, characterized in that: The target wireless access technology type is determined by the second terminal, and the method further includes: A fifth message is received from the second terminal, where the fifth message includes indication information of the target radio access technology type.

14. The method according to claim 11 or 12, characterized in that: The target radio access technology type is determined by the access and mobility management function network element, and the method further includes: A sixth message is sent to the second terminal, where the sixth message includes indication information of the target wireless access technology type.

15. The method according to any one of claims 11 to 14, characterized in that The target radio access technology type is the fourth radio access technology type, and the fourth paging message further includes indication information of the third radio access technology type.

16. The method according to any one of claims 11 to 15, characterized in that The state of the second terminal corresponding to the third radio access technology type is an idle state.

17. A paging method, characterized in that: The method is applied to a second terminal, comprising: receiving a fifth paging message, the fifth paging message being received through a target access network device corresponding to a target radio access technology type, the fifth paging message including an identifier of the second terminal, the target radio access technology type being determined by the second terminal or an access and mobility management function network element, the second terminal registering with the access and mobility management function network element through an access network device of the third radio access technology type and an access network device of a fourth radio access technology type, the target radio access technology type being the third radio access technology type or the fourth radio access technology type; in a case where the target radio access technology type is the fourth radio access technology type, the fifth paging message also including indication information of the third radio access technology type; A seventh message is sent to the access and mobility management function network element through the access network device corresponding to the third wireless access technology type, wherein the seventh message includes an identifier of the second session corresponding to the third wireless access technology type, and the seventh message is used to request restoration of the communication connection of the second session.

18. The method according to claim 17, characterized in that The receiving the fifth paging message includes: receiving the fifth paging message according to the target wireless access technology type.

19. The method according to claim 17 or 18, characterized in that The target access network device is in the registration area corresponding to the target wireless access technology type.

20. The method according to any one of claims 17 to 19, characterized in that The target radio access technology type is the third radio access technology type, and the method further includes: Sending a fifth registration request to the access and mobility management function network element, where the fifth registration request is sent through the access network device of the third radio access technology type; A fifth registration response is received from the access and mobility management function network element, where the fifth registration response includes a third registration area associated with the third radio access technology type.

21. The method of claim 20, wherein: The method further includes: storing an association between the third radio access technology type and the third registration area.

22. The method according to any one of claims 17 to 19, characterized in that The target radio access technology type is the fourth radio access technology type, and the method further includes: Sending a sixth registration request to the access and mobility management function network element, where the sixth registration request is sent through the access network device of the fourth radio access technology type; A sixth registration response is received from the access and mobility management function network element, where the sixth registration response includes a fourth registration area associated with the fourth radio access technology type.

23. The method of claim 22, wherein: The method further includes: storing an association between the fourth radio access technology type and the fourth registration area.

24. The method according to any one of claims 17 to 23, characterized in that The target wireless access technology type is determined by the second terminal, and the method further includes: A fifth message is sent to the access and mobility management function network element, where the fifth message includes indication information of the target radio access technology type.

25. The method according to any one of claims 17 to 23, characterized in that The target radio access technology type is determined by the access and mobility management function network element, and the method further includes: A sixth message is received from the access and mobility management function network element, where the sixth message includes indication information of the target radio access technology type.

26. The method according to any one of claims 17 to 25, characterized in that The method further comprises: A fourth cell is determined according to the third radio access technology type, where the fourth cell is a cell provided by an access network device corresponding to the third radio access technology type.

27. The method according to any one of claims 17 to 26, characterized in that The state of the second terminal corresponding to the third radio access technology type is an idle state.

28. A communication device, characterized in that: The method comprises a unit for implementing the method according to any one of claims 1 to 10, or a unit for implementing the method according to any one of claims 11 to 16, or a unit for implementing the method according to any one of claims 17 to 27.

29. A communication device, characterized in that: The invention comprises a processor and a memory, wherein the processor and the memory are coupled, and the processor is used to implement the method according to any one of claims 1 to 10, or implement the method according to any one of claims 11 to 16, or implement the method according to any one of claims 17 to 27.

30. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, which are executed on a computer to enable the computer to execute the method according to any one of claims 1 to 10, or the method according to any one of claims 11 to 16, or the method according to any one of claims 17 to 27.

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