Communication method, system and apparatus, and device, chip and storage medium

Abstract

Provided in the embodiments of the present application are a communication method, system and apparatus, and a device, a chip and a storage medium. The method comprises: a terminal device receiving first information; and when accessing a first network, sending a service request message or a mobility registration request message on the first network on the basis of the first information.

Description

A communication method, system, apparatus, device, chip, and storage medium Technical Field

[0001] This application relates to the field of mobile communication technology, specifically to a communication method and system, apparatus, device, chip, and storage medium. Background Technology

[0002] If there are few base stations in the Radio Access Network (RAN), User Equipment (UE) may frequently move in and out of the network's coverage area, resulting in a significant signaling burden. To reduce this signaling burden, the UE can connect to different RANs simultaneously. However, this requires the UE to support dual radios, complicating UE implementation. Summary of the Invention

[0003] This application provides a communication method and system, apparatus, device, chip, and storage medium.

[0004] In a first aspect, the communication method provided in the embodiments of this application is applied to a terminal device, and the method includes:

[0005] The terminal device receives the first information; when accessing the first network, it sends a service request message or a mobility registration request message on the first network according to the first information.

[0006] Secondly, the communication method provided in the embodiments of this application is applied to a first network device, and the method includes:

[0007] Send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used for the terminal device to send a service request message or a mobility registration request message.

[0008] Thirdly, the communication method provided in the embodiments of this application is applied to a second network device, and the method includes:

[0009] Send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used for the terminal device to send a service request message or a mobility registration request message.

[0010] Fourthly, the communication method provided in this application embodiment is applied to a third network device, and the method includes:

[0011] Send a type confirmation message to the second network device; wherein the type confirmation message is used to indicate whether the first network is available.

[0012] Fifthly, the communication method provided in the embodiments of this application is applied to a first communication system, the first communication system including at least a second network device and a third network device, and the method includes:

[0013] The second network device sends an update request message to the third network device; wherein the update request message carries a type indication message, which is used to indicate the supported Radio Access Technology (RAT) type;

[0014] The third network device sends an update response message to the second network device; wherein the update response message carries a type confirmation message, which is used to indicate whether the first network is available; the first network uses the first RAT.

[0015] Sixthly, the communication method provided in the embodiments of this application is applied to a second communication system, the second communication system including at least a terminal device and a second network device, and the method includes:

[0016] The second network device sends first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; wherein the first network uses a first RAT;

[0017] When a terminal device accesses the first network, it sends a service request message or a mobility registration request message on the first network based on the first information.

[0018] Seventhly, the communication device provided in the embodiments of this application is applied to a terminal device, and the device includes:

[0019] The first receiving unit is configured to receive the first information;

[0020] The first sending unit is configured to send a service request message or a mobility registration request message on the first network according to the first information when the terminal device accesses the first network.

[0021] Eighthly, the communication apparatus provided in the embodiments of this application is applied to a first network device, and the apparatus includes:

[0022] The second sending unit is configured to send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used by the terminal device to send a service request message or a mobility registration request message.

[0023] Ninthly, the communication apparatus provided in the embodiments of this application is applied to a second network device, and the apparatus includes:

[0024] The third sending unit is configured to send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used by the terminal device to send a service request message or a mobility registration request message.

[0025] Tenthly, the communication apparatus provided in the embodiments of this application is applied to a third network device, and the apparatus includes:

[0026] The fourth sending unit is configured to send a type confirmation message to the second network device; wherein the type confirmation message is used to indicate whether the first network is available.

[0027] Eleventhly, the terminal device provided in the embodiments of this application includes a processor and a memory. The memory is used to store computer programs, and the processor is used to call and run the computer programs stored in the memory to execute the communication method performed by the terminal device.

[0028] In a twelfth aspect, the first network device provided in the embodiments of this application includes a processor and a memory. The memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the communication method performed by the first network device described above.

[0029] In a thirteenth aspect, the second network device provided in this application includes a processor and a memory. The memory stores a computer program, and the processor calls and runs the computer program stored in the memory to execute the communication method performed by the second network device.

[0030] In a fourteenth aspect, the third network device provided in this application includes a processor and a memory. The memory stores a computer program, and the processor calls and runs the computer program stored in the memory to execute the communication method performed by the third network device.

[0031] In a fifteenth aspect, the chip provided in this application embodiment is used to implement the above-described communication method. Specifically, the chip includes a processor for calling and running a computer program from a memory, causing a device equipped with the chip to execute the above-described communication method.

[0032] In a sixteenth aspect, the computer-readable storage medium provided in the embodiments of this application is used to store a computer program that causes a computer to perform the above-described communication method.

[0033] In a seventeenth aspect, the computer program product provided in the embodiments of this application includes computer program instructions that cause a computer to perform the above-described communication method.

[0034] In an eighteenth aspect, the computer program provided in the embodiments of this application, when run on a computer, causes the computer to perform the above-described communication method.

[0035] This application provides a communication method in which a terminal device can select, based on first information, whether to send a service request message or a mobility registration request message when accessing a first network. This method can avoid the need for dual radios for the terminal device to support its movement in different networks, thereby saving signaling. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0037] Figure 1 is a schematic diagram of an application scenario of an embodiment of this application;

[0038] Figure 2 is a schematic diagram of an exemplary conventional 5G architecture provided in an embodiment of this application;

[0039] Figure 3 is a schematic diagram of an exemplary core network provided in an embodiment of this application;

[0040] Figure 4 is a schematic diagram of an exemplary core network provided in an embodiment of this application;

[0041] Figure 5 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0042] Figure 6 is a schematic diagram of an exemplary terminal device registering in a first network according to an embodiment of this application;

[0043] Figure 7 is a schematic diagram of an exemplary terminal device registering in a first network according to an embodiment of this application;

[0044] Figure 8 is a schematic diagram of an exemplary process for a terminal device to register in a second network according to an embodiment of this application;

[0045] Figure 9 is a schematic diagram of an exemplary process for a terminal device to register in a second network according to an embodiment of this application;

[0046] Figure 10 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0047] Figure 11 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0048] Figure 12 is a schematic diagram of an exemplary process for a terminal device to register in a second network according to an embodiment of this application;

[0049] Figure 13 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0050] Figure 14 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0051] Figure 15 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0052] Figure 16 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0053] Figure 17 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0054] Figure 18 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0055] Figure 19 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0056] Figure 20 is a schematic flowchart of an exemplary communication method provided in an embodiment of this application;

[0057] Figure 21 is a schematic diagram of an exemplary communication device provided in an embodiment of this application;

[0058] Figure 22 is a schematic diagram of the structure of an exemplary communication device provided in an embodiment of this application;

[0059] Figure 23 is a schematic diagram of the structure of an exemplary communication device provided in an embodiment of this application;

[0060] Figure 24 is a schematic diagram of the structure of an exemplary communication device provided in an embodiment of this application;

[0061] Figure 25 is a schematic structural diagram of an exemplary communication device provided in an embodiment of this application;

[0062] Figure 26 is a schematic structural diagram of an exemplary chip provided in an embodiment of this application;

[0063] Figure 27 is a schematic diagram of an exemplary first communication system provided in an embodiment of this application;

[0064] Figure 28 is a schematic diagram of an exemplary second communication system provided in an embodiment of this application. Detailed Implementation

[0065] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0066] Figure 1 is a schematic diagram of an application scenario according to an embodiment of this application.

[0067] As shown in Figure 1, the communication system 100 may include a terminal device 110 and a network device 120. The network device 120 can communicate with the terminal device 110 via an air interface. Multi-service transmission is supported between the terminal device 110 and the network device 120.

[0068] It should be understood that the embodiments of this application are only illustrated by way of example with communication system 100, but the embodiments of this application are not limited thereto. That is to say, the technical solutions of the embodiments of this application can be applied to various communication systems, such as: Long Term Evolution (LTE) system, LTE Time Division Duplex (TDD), Universal Mobile Telecommunication System (UMTS), Internet of Things (IoT) system, Narrow Band Internet of Things (NB-IoT) system, enhanced Machine-Type Communications (eMTC) system, 5G (also known as New Radio (NR) communication system), Sixth Generation Mobile Communication Technology (6G) or future communication systems, etc.

[0069] In the communication system 100 shown in Figure 1, network device 120 may be an access network device that communicates with terminal device 110. The access network device can provide communication coverage for a specific geographical area and can communicate with terminal device 110 (e.g., user equipment (UE)) located within that coverage area.

[0070] Network device 120 may be an evolved Node B (eNB or eNodeB) in a Long Term Evolution (LTE) system, or a Next Generation Radio Access Network (NG RAN) device, or a base station (gNB) in an NR system, or a 6G-Radio Access Network (6G-RAN), or a radio controller in a Cloud Radio Access Network (CRAN), or the network device 120 may be a relay station, access point, vehicle-mounted equipment, wearable device, hub, switch, bridge, router, or network equipment in a future evolved Public Land Mobile Network (PLMN), etc.

[0071] Terminal device 110 can be any terminal device, including but not limited to terminal devices that are connected to network device 120 or other terminal devices via wired or wireless connections.

[0072] For example, the terminal device 110 can refer to an Ambient-Internet of Things (A-IoT) device, access terminal, UE, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. The access terminal can be a cellular phone, cordless phone, Session Initiation Protocol (SIP) phone, IoT device, satellite handheld terminal, Wireless Local Loop (WLL) station, Personal Digital Assistant (PDA), handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, in-vehicle device, wearable device, terminal device in a 5G network, or terminal device in a future evolved network, etc.

[0073] Terminal device 110 can be used for device-to-device (D2D) communication.

[0074] The wireless communication system 100 may further include a core network device 130 that communicates with the network device 120. This core network device 130 may be a 5G core network (5G Core, 5GC) device, such as an Access and Mobility Management Function (AMF), an Authentication Server Function (AUSF), a User Plane Function (UPF), or a Session Management Function (SMF). Optionally, the core network device 130 may also be an Evolved Packet Core (EPC) device for an LTE network, such as a Session Management Function + Core Packet Gateway (SMF+PGW-C) device. It should be understood that SMF+PGW-C can simultaneously implement the functions of both SMF and PGW-C. During network evolution, the aforementioned core network device may also be called by other names, or new network entities may be formed by dividing the core network functions; this embodiment does not limit this.

[0075] In some embodiments, the functional units in the communication system 100 can also communicate with each other through a Next Generation (NG) interface.

[0076] For example, terminal device 110 establishes an air interface connection with access network equipment through the NR interface for transmitting user plane data and control plane signaling; terminal device 110 can establish a control plane signaling connection with AMF through NG interface 1 (N1); access network equipment, such as next-generation radio access base station (gNB), can establish a user plane data connection with UPF through NG interface 3 (N3); access network equipment can establish a control plane signaling connection with AMF through NG interface 2 (N2); UPF can establish a control plane signaling connection with SMF through NG interface 4 (N4); UPF can interact with data network for user plane data through NG interface 6 (N6); AMF can establish a control plane signaling connection with SMF through NG interface 11 (N11); SMF can establish a control plane signaling connection with PCF through NG interface 7 (N7).

[0077] Figure 1 exemplarily illustrates a network device 120, a core network device 130, and two terminal devices 110. Optionally, the wireless communication system 100 may include multiple network devices 120, and the coverage area of ​​each network device 120 may include other numbers of terminal devices 110. This application embodiment does not limit this.

[0078] It should be noted that Figure 1 is merely an example illustrating the system to which this application applies. Of course, the method shown in the embodiments of this application can also be applied to other systems. Furthermore, the terms "system" and "network" are often used interchangeably in this document. The term "and / or" in this document merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. It should also be understood that in some embodiments, "instruction" can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, for example, B can be obtained through A; it can also mean that A indirectly instructs B, for example, A instructs C, B can be obtained through C; or it can mean that there is a relationship between A and B. It should also be understood that in some embodiments, "correspondence" can indicate a direct or indirect correspondence between two objects, or an association between two objects, or a relationship of instruction and being instructed, configuration and being configured, etc. It should also be understood that the "predefined" or "predefined rules" mentioned in some embodiments can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device (e.g., including terminal devices and network devices), and this application does not limit the specific implementation method. For example, predefined can refer to those defined in a protocol. It should also be understood that in the embodiments of this application, the "protocol" can refer to standard protocols in the field of communication, such as the LTE protocol, the NR protocol, and related protocols applied to future communication systems, and this application does not limit this.

[0079] To facilitate understanding of the technical solutions of the embodiments of this application, the relevant technologies of the embodiments of this application are described below. The following relevant technologies are optional solutions and can be combined with the technical solutions of the embodiments of this application in any way, and they all fall within the protection scope of the embodiments of this application.

[0080] The traditional 5G architecture is shown in Figure 2. In Figure 2, the UE connects to the Access Network (AN) via the Uu interface to establish an access layer connection, exchanging access layer messages and radio data. The UE connects to the AMF via the N1 interface to establish a non-access layer (NAS) connection, exchanging NAS messages. The AMF is the mobility management function in the core network, and the SMF is the session management function in the core network. In addition to managing the UE's mobility, the AMF is also responsible for forwarding session management-related messages between the UE and the SMF. The Policy Control Function (PCF) in the core network is responsible for formulating policies related to UE mobility management, session management, and charging. The UPF is the user plane function in the core network, transmitting data with the external Data Network (DN) via the N6 interface and with the AN via the N3 interface. After the UE accesses the 5G network through the Uu port, it establishes a Protocol Data Unit (PDU) session for data transmission under the control of the SMF. In addition to the above interactions, the AN connects to the AMF through the N2 port; the UPF connects to the SMF through the N4 port and interacts with itself through the N9 port; the AMF interacts with itself through the N14 port, and also interacts with the PCF through the N15 port, and with the SMF through the N11 port. It also interacts with the Network Slice Selection Function (NSSF), AUSF, and Unified Data Management (UDM) through the N22, N12, and N8 ports, respectively; the SMF interacts with the PCF through the N7 port and with the UDM through the N10 port; the PCF interacts with the Application Function (AF) through the N5 port; and the AUSF interacts with the UDM through the N13 port.

[0081] The 3rd Generation Partnership Project (3GPP) has begun research on 6G requirements and use cases. For supporting 6G Radio Access Networks (RANs), there are generally two approaches:

[0082] The first approach is shown in Figure 3. In Figure 3, two core networks, namely 5G-AMF and 6G-AMF, are deployed independently under 5G+6G-SMF, thereby supporting UE access to 5G-RAN and 6G-RAN respectively.

[0083] The second approach is shown in Figure 4. In Figure 4, a shared core network is used. A core network, namely 5G+6G-AMF, is deployed under 5G+6G-SMF. Thus, UE access to 5G-RAN and 6G-RAN are supported respectively.

[0084] In the early stages of 6G deployment, operators started by deploying 6G base stations in hotspot areas, and there were relatively few 6G-RAN base stations. This caused UEs to frequently move in and out of the 6G coverage area, resulting in a lot of signaling burden. To reduce this signaling burden, UEs can connect to both 5G-RAN and 6G-RAN simultaneously. However, this requires the UE to support dual radio, which makes the UE implementation more complex.

[0085] In view of this, embodiments of this application provide a communication method in which a terminal device can select, based on first information, whether to send a service request message or a mobility registration request message when accessing a first network. This method can avoid the need for dual radios for the terminal device to support its movement in different networks, thereby saving signaling.

[0086] To facilitate understanding of the technical solutions of the embodiments of this application, the technical solutions of this application are described in detail below through specific embodiments. The above-mentioned related technologies are optional solutions and can be arbitrarily combined with the technical solutions of the embodiments of this application, all of which fall within the protection scope of the embodiments of this application. The embodiments of this application include at least some of the following contents.

[0087] Figure 5 shows a flowchart of a communication method provided in an embodiment of this application, applied to a terminal device. The method may include:

[0088] S500, the terminal device receives the first information.

[0089] In some embodiments, the terminal device may first receive first information. This first information may be sent from the network device to the terminal device.

[0090] In some embodiments, the first information may include, but is not limited to, the registration result. In this application, the "Registration Result" field, which represents the first information, is given a meaning different from that in related technologies, for example, by adding a new value for this field.

[0091] In other embodiments, the first information may be represented by other fields, or a new field may be added to represent the first information. This embodiment does not limit this.

[0092] In some embodiments, the first information indicates the mobility registration result of the terminal device. In one embodiment, the mobility registration result of the terminal device includes at least one of the following: the mobility registration result of the terminal device on a first network; the mobility registration result of the terminal device on a second network. In one embodiment, the name of the first information is not specifically limited, such as registration result indication, registration validity indication, etc. In one example, the first information can be a "Registration Result" field. This field can be carried in a registration acceptance message or a registration rejection message during the registration process.

[0093] In some embodiments, the first information indicates the mobility registration result of the terminal device, which can be understood as the result of the terminal device's previous mobility registration.

[0094] In some implementations, the first information at least indicates the mobility registration result of the terminal device on the first network. The mobility registration result of the terminal device on the first network includes one of the following: the registration of the terminal device on the first network is valid; or the registration of the terminal device on the first network is invalid.

[0095] In some embodiments, the first network may be a radio access network employing a first RAT. The first RAT may include, but is not limited to, 5G or 6G, and correspondingly, the first network may be a 5G network or a 6G network. The specific first network can be determined according to actual circumstances, and this application does not limit it.

[0096] In some embodiments, valid registration of the terminal device on the first network can be understood as the terminal device's registration on the first network being available, or it can also be understood as the terminal device's UE context being available in the first network.

[0097] In some embodiments, invalid registration of the terminal device on the first network can be understood as the terminal device being unavailable for registration on the first network, or it can also be understood as the UE context of the terminal device being unavailable in the first network.

[0098] In some implementations, the terminal device can determine, based on the first information, that its registration on the first network is valid and its registration on the second network is valid; or, the terminal device can determine, based on the first information, that its registration on the first network is valid and its registration on the second network is invalid; or, the terminal device can determine, based on the first information, that its registration on the first network is invalid and its registration on the second network is valid.

[0099] In some embodiments, the second network uses a different RAT than the first network; in other words, the first network and the second network are networks using different RATs. In one embodiment, the second network can be a network using a second RAT. The second RAT can include, but is not limited to, 5G or 6G. Accordingly, the second network can be, but is not limited to, a 5G network or a 6G network. The specific second network can be determined according to actual circumstances, and this application embodiment does not limit it.

[0100] For example, the first network can be a 5G network and the second network can be a 6G network. In one example, the first network can be a 6G network and the second network can be a 5G network. The specific first and second networks can be determined according to the actual situation, and this application does not limit them.

[0101] In some embodiments, if the registration of the terminal device on the first network is invalid, the first information may directly indicate that the registration on the first network is invalid, or it may indicate that the registration of the terminal device is valid only on other networks (e.g., the second network), so that the terminal device can determine that the registration on the first network is invalid based on the first information.

[0102] For example, the first information indicates that the terminal device's registration is valid on both the first network and the second network (e.g., the terminal device's registration is 5G and 6G, referred to as 5G+6G), or the first information indicates that the terminal device's registration is valid only on the first network (e.g., the terminal device's registration is only on 5G, referred to as 5G only), or the first information indicates that the terminal device's registration is valid only on the second network (e.g., the terminal device's registration is only on 6G, referred to as 6G only).

[0103] In some embodiments, assuming the first network can be a 5G network and the second network can be a 6G network, the first information indicating the mobility registration result of the terminal device on the first network can include the terminal device's registration on the 5G network being valid, and the registration on the 5G network being valid. In this case, the meaning of the "Registration Result" field can include 5G+6G.

[0104] In some embodiments, assuming the first network can be a 5G network and the second network can be a 6G network, the first information indicating the mobility registration result of the terminal device on the first network may include the terminal device's registration on the 5G network being valid and the registration on the 6G network being invalid. In this case, the meaning of the corresponding "Registration Result" field may include 5G only.

[0105] In some embodiments, assuming the first network can be a 5G network and the second network can be a 6G network, the first information indicating the mobility registration result of the terminal device on the first network may include the terminal device's registration on the 5G network being invalid and the registration on the 5G network being valid. In this case, the meaning of the corresponding "Registration Result" field may include 6G only.

[0106] Therefore, assuming the first network can be a 5G network and the second network can be a 6G network, when informing the terminal device of its mobility registration result on the first network through the first information, if the first information indicates 6G only, it can be determined that the terminal device's mobility registration result on the first network is invalid; if the first information indicates 5G only, it can be determined that the terminal device's mobility registration result on the first network is valid; and if the first information indicates 5G+6G, it can be determined that the terminal device's mobility registration result on the first network is valid.

[0107] S501. When the terminal device accesses the first network, it sends a service request message or a mobility registration request message on the first network according to the first information.

[0108] In some embodiments, when a terminal device accesses a first network, it may send a service request message or a mobility registration request message on the first network based on the received first information.

[0109] In some embodiments, the first information is received by the terminal device before accessing the first network. Therefore, when accessing the first network, the terminal device can choose to send a service request message or a mobility registration request message on the first network based on the first information.

[0110] In some embodiments, when a terminal device accesses a first network, it can determine whether its registration on the first network is valid based on first information, and then choose to send a service request message or a mobility registration request message on the first network depending on whether the registration is valid or invalid.

[0111] In some embodiments, the first information indicates the registration result of the terminal device's previous mobility registration with the first network. That is, the terminal device has already established mobility registration with the first network before accessing the first network. Therefore, when accessing the first network, the terminal device can refer to the previous mobility registration result on the first network to send subsequent information.

[0112] In some embodiments, the scenarios in which a terminal device accesses the first network may include, but are not limited to, the terminal device moving from the registration area of ​​the second network to the registration area of ​​the network, or the terminal device switching the network it accesses from the second network to the first network, or the terminal device being within the coverage area of ​​the first network.

[0113] In other words, the terminal device accessing the first network may include, but is not limited to: the terminal device moving to the first network, or the terminal device switching to the first network, or the terminal device connecting to any one of the first networks.

[0114] In some embodiments, the terminal device is currently in the registration area of ​​a second network. When moving from the registration area of ​​the second network to the registration area of ​​the first network, it can send a service request message or a mobility registration request message on the first network according to the first information. The second network is different from the first network.

[0115] In some embodiments, when a terminal device is currently connected to a second network and switches from the second network to a first network, it can send a service request message or a mobility registration request message on the first network based on first information. The second network is different from the first network.

[0116] In some embodiments, when a terminal device is currently moving to the coverage area of ​​a first network and accessing the first network, it can send a service request message or a mobility registration request message on the first network based on the first information.

[0117] For example, the first network is a 5G network and the second network is a 6G network. When a terminal device accesses the 5G network from the 6G network, it can send a service request message or a mobility registration request message on the first network according to the first information. The terminal device can determine that it is moving from the 6G network to the 5G network based on the change of the current access registration area from the 6G network registration area to the 5G network registration area, or the terminal device can determine that it is moving from the 6G network to the 5G network based on the change of the current access cell from the 6G cell to the 5G cell.

[0118] For example, the first network is a 6G network and the second network is a 5G network. When the terminal device accesses the 6G network from the 5G network, it can send a service request message or a mobility registration request message on the first network according to the first information. The terminal device can determine whether it is moving from the 5G network to the 6G network based on whether the current access registration area changes from the 5G network registration area to the 6G network registration area. Alternatively, the terminal device can determine whether it is moving from the 5G network to the 6G network based on whether the current access cell changes from the 5G cell to the 6G cell.

[0119] In some embodiments, the service request message can be a service request, the mobility registration request message can be a mobility update registration request message, or a registration request message with a registration type of mobility update; the specific service request message and mobility registration request message can be determined according to the actual situation, and are not limited herein.

[0120] In some implementations, when accessing the first network, the terminal device sends a service request message on the first network based on first information; wherein, the first information indicates that the terminal device's registration on the first network is valid; the service request message is used for the terminal device to access the first network.

[0121] In some embodiments, if the first information is used to indicate that the terminal device’s registration on the first network is valid, or to indicate that the terminal device’s registration on the first network is available, or to indicate that the terminal device’s context in the first network is available, the terminal device can directly access the first network using the first RAT, thereby the terminal device sends a service request message on the first network.

[0122] For example, assuming the first network is a 6G network, before the terminal device accesses the 6G network, it is determined that the terminal device's registration on the 6G network is valid based on the first information. Therefore, when the terminal device accesses the 6G network, it can directly send a Service request for accessing the 6G network on the 6G network.

[0123] In some implementations, when accessing a first network, the terminal device sends a mobility registration request message on the first network based on first information; wherein the first information indicates that the terminal device's registration on the first network is invalid; the mobility registration request message is used by the terminal device to request registration in the first network; the first network adopts a first RAT.

[0124] In some embodiments, the first information is used to indicate that the terminal device's registration on the first network is invalid, or that the terminal device's registration on the first network is unavailable, or that the terminal device's context in the first network is unavailable. The terminal device needs to re-register on the first network via a mobility registration request message before it can access the first network. Therefore, the terminal device can send a mobility registration request message on the first network when accessing it.

[0125] For example, assuming the first network is a 5G network, before the terminal device accesses the 5G network, it is determined that the terminal device's registration on the 5G network is valid based on the first information. Therefore, when the terminal device accesses the 5G network, it needs to send a mobility registration request message on the 5G network to request registration in the 5G network.

[0126] In some implementations, the first information may be sent by a first network device. For example, a terminal device receives the first information sent by the first network device; wherein, the first network device at least supports the ability to retain context when the terminal device accesses the second network.

[0127] In some implementations, the first information may be sent by a second network device. For example, a terminal device receives the first information sent by a second network device.

[0128] In the embodiments of this application, the first information can be sent by any network device, including but not limited to the first network device and the second network device, and this application does not make any specific limitation.

[0129] In some embodiments, the terminal device is in an idle state. In one embodiment, the terminal device being in an idle state can be understood as the terminal device being in a connection management idle state (CM-Idle), or it can be understood as the terminal device being in a user registration management idle state (MM-Idle).

[0130] In some implementations, the CM Idle state (CM-Idle) refers to the state when a terminal device has not established a signaling connection with the Access Management Function (AMF) in the 5G core network. In the CM Idle state, the terminal device is idle and not communicating with the core network. At this time, the network may temporarily remove resources used for data transmission to conserve network resources. When the terminal device needs to initiate communication or receive data, it will transition from the CM Idle state to the CM Connected state.

[0131] In some implementations, the MM-Idle state refers to a state where the terminal device has not yet registered with the network, or its registration has been cancelled, and therefore no registration relationship has been established with the network side. In the MM-Idle state, the terminal device cannot access network services and may need to complete a registration process to access network services.

[0132] In some embodiments, since the first network device has the ability to retain the context of the terminal device on the first network after the terminal device accesses the second network from the first network, the first network device can retain the registration information of the terminal device on the first network. Therefore, the first information can indicate that the registration of the terminal device on the first network is valid (or optionally indicate that the registration is invalid). Based on this, when the terminal device re-accesses the first network, it can choose to send a service request message or a mobility registration request message according to the first information. For example, after the terminal device moves from the first network to the second network, if it receives the first information from the second network device indicating that the registration of the terminal device on the first network is valid, then when it subsequently re-accesses the first network, it can send a service request message on the first network. Based on this, the terminal device can directly access the first network using the first RAT.

[0133] In some embodiments, the first network device is the core network device of the first RAT.

[0134] In some embodiments, if the first RAT is 5G and the first network is a 5G network, then the first network device can be a 5G-AMF; if the first RAT is 6G and the first network is a 6G network, then the first network device can be a 6G-AMF.

[0135] For example, when a terminal device accesses a 6G network from a 5G network, since the 5G-AMF corresponding to the 5G network has the ability to retain context, the registration information of the terminal device on the 5G network can be retained. Based on this, if the first information indicates that the registration of the terminal device on the 5G network is valid, when the terminal device re-accesses the 5G network, the terminal device can choose to directly access the 5G network without registering again.

[0136] In some embodiments, the first network device is the core network device of a first RAT, and the second network device is the core network device of a second RAT. That is, the first network device can be a core network device using the first RAT, and the second network device can be a core network device using the second RAT. In this case, the core network device of the first RAT and the core network device of the second RAT are two independently deployed network devices.

[0137] In some embodiments, the first network device is a core network device of a first RAT and a core network device of a second RAT that are centrally deployed. That is, the first network device can be a device that has deployed core network devices using the first RAT and core network devices using the second RAT. In this case, the core network devices of the first RAT and the core network devices of the second RAT are centrally deployed in the first network device.

[0138] In some embodiments, the second network device is a core network device of both the first RAT and the second RAT that are centrally deployed. That is, the second network device can be a device that deploys both a core network device using the first RAT and a core network device using the second RAT. In this case, the core network devices of the first and second RATs are centrally deployed within the second network device.

[0139] In one possible communication scenario, the core network devices of the first RAT and the second RAT are two independently deployed network devices. Terminal devices need to register with the first network device to access the first network, and similarly, terminal devices also need to register with the second network device to access the second network.

[0140] In some implementations, the terminal device may also perform the following steps: sending a registration request message to a first network device; receiving a registration acceptance message sent by the first network device; and sending a registration completion message to the first network device; wherein the first information is carried in the registration acceptance message received by the terminal device from the first network device.

[0141] In some embodiments, the terminal device needs to register with the first network device to access the first network. Referring to Figure 6, the specific registration process includes: First, the terminal device sends a registration request message to the first network device. Then, after receiving the registration request message, the first network device sends a registration acceptance message to the terminal device. At the same time, the registration acceptance message may carry first information indicating that the terminal device's registration on the first network is valid. Finally, after receiving the registration acceptance message, the terminal device returns a registration completion message to the first network device to confirm that the terminal device's registration on the first network device is effective. Thus, the terminal device accesses the first network.

[0142] In some embodiments, the first information carried in the registration acceptance message sent by the first network device to the terminal device may only indicate that the registration of the terminal device on the first network is valid. For example, if the first network is a 5G network, the first information indicates 5G only.

[0143] In some implementations, the terminal device receives a first identifier sent by the first network device; wherein the first identifier is carried in a registration acceptance message sent by the first network device received by the terminal device, and the first identifier is a temporary identifier used by the terminal device in the first RAT.

[0144] In some embodiments, the first identifier can be a globally unique temporary identifier (GUTI). If the first network is a 5G network and the first network device is a core network device in the 5G network, then the first identifier is 5G-GUTI. If the first network is a 6G network and the first network device is a core network device in the 6G network, then the first identifier is 6G-GUTI.

[0145] In some embodiments, referring to FIG7, after receiving a registration request message from a terminal device, the first network device triggers an authentication process. At this time, the first network device sends a security mode command message to the terminal device. The terminal device returns a security mode completion message to the first network device according to the security mode command message. Thus, authentication is completed. The first network device can then send a registration acceptance message to the terminal device. After receiving the registration acceptance message, the terminal device returns a registration completion message to the first network device to confirm that the registration of the terminal device on the first network device is effective. Thus, the terminal device accesses the first network.

[0146] In some embodiments, the registration request message sent by the terminal device to the first network device carries the UE identification number (ID). The UE ID may be a Subscription Concealed Identifier (SUCI) or GUTI, as well as the registration type - initial registration or mobility update registration, and UE security capabilities.

[0147] In some embodiments, the Security Mode Command message is a Security Mode Command message. The Security Mode Command message carries the index information of the security key, also known as the Key Set Identifier (KSI), UE security capabilities, integrity algorithm, ciphering algorithm, and Initial NAS message request indication.

[0148] In some embodiments, the Security Mode Complete message is a Security Mode Complete message. This message carries a registration request message sent by the second network device to the terminal device. The registration request message may include information such as the registration type, 5G-GUTI, UE capability information, and the requested network slice (Requested NSSAI). The registration type can be mobility management registration or mobility registration for 5G to 6G transition.

[0149] In some embodiments, in addition to carrying the first identifier and the first information, the registration acceptance message received by the terminal device from the first network device may also carry information such as the registration area and the available network slice (Allowed Network Slice Selection Assistance Information, Allowed NSSAI).

[0150] In one possible communication scenario, the core network devices of the first RAT and the second RAT are two independently deployed network devices. Terminal devices need to register with the first network device to access the first network, and similarly, terminal devices also need to register with the second network device to access the second network.

[0151] In some implementations, the terminal device may also perform the following steps: sending a registration request message to the second network device; receiving a registration acceptance message sent by the second network device; and sending a registration completion message to the second network device; wherein the first information is carried in the registration acceptance message received by the terminal device from the second network device.

[0152] In some embodiments, the terminal device needs to register with the second network device to access the second network. Referring to Figure 8, the specific registration process includes: First, the terminal device sends a registration request message to the second network device. Then, after receiving the registration request message, the second network device sends a registration acceptance message to the terminal device. At the same time, the registration acceptance message may carry first information to indicate that the terminal device's registration on the second network is valid. Finally, after receiving the registration acceptance message, the terminal device returns a registration completion message to the second network device to confirm that the terminal device's registration on the second network device is effective.

[0153] In some embodiments, the first information carried in the registration acceptance message sent by the second network device to the terminal device may indicate only that the terminal device's registration on the second network is valid. For example, if the second network is a 6G network, the first information may indicate 6G only. Alternatively, the first information may indicate that the terminal device's registration on the first network is valid while also indicating that the terminal device's registration on the second network is valid. This can be understood as indicating that the terminal device's registration on both the first and second networks is valid. For example, if the first network is a 5G network and the second network is a 6G network, the first information may indicate 5G+6G.

[0154] In some implementations, the terminal device sends a first identifier to the second network device; wherein the first identifier is carried in a registration request message sent by the terminal device to the second network device.

[0155] In some embodiments, the terminal device may carry a first identifier in the registration request message sent to the second network device, thereby the second network device may determine that the terminal device has previously registered on the first network device based on the first identifier.

[0156] In some implementations, the terminal device receives a second identifier sent by the second network device; wherein the second identifier is carried in a registration acceptance message sent by the second network device received by the terminal device, and the second identifier is a temporary identifier used by the terminal device in the second RAT.

[0157] In some embodiments, the second identifier can be a GUTI. If the second network is a 5G network, then the second identifier is 5G-GUTI; if the second network is a 6G network, then the second identifier is 6G-GUTI.

[0158] In some embodiments, referring to FIG9, after receiving a registration request message from a terminal device, the second network device can identify the first network device based on the first identifier carried in the registration request message, and then send a context request message to the first network device. The first network device returns a context response message to the second network device based on the context request message. After receiving the context response message, the second network device sends a context confirmation message to the first network device. Finally, the second network device sends a registration acceptance message to the terminal device. After receiving the registration acceptance message, the terminal device returns a registration completion message to the second network device to confirm that the registration of the terminal device on the second network device has taken effect. Thus, the terminal device accesses the second network.

[0159] In some embodiments, the registration request message sent by the terminal device to the second network device may carry information such as registration type, first identifier, UE capability information, and requested network slice (Requested NSSAI). The registration type may be mobility management registration or mobility registration for 5G to 6G transition.

[0160] For example, the context request message can be a Namf_Communication_UEContext Transfer Request message.

[0161] For example, the context response message can be a Namf_Communication_UEContext Transfer Response message. The Namf_Communication_UEContext Transfer Response message can carry the UE context, including security context, PDU session information (PDU session ID), Single Network Slice Selection Assist (Single NSSAI, S NSSAI), SMF information corresponding to each PDU session control, Allowed NSSAI, and UE capability information.

[0162] For example, the context acknowledgment message can be the Namf_Communication_UEContext Transfer Ack message.

[0163] In some embodiments, in addition to carrying the second identifier and the first information, the registration acceptance message received by the terminal device from the second network device may also carry information such as the registration area and the available network slice (Allowed NSSAI).

[0164] In some implementations, the first network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed; and / or, the second network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed.

[0165] In some embodiments, the first network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed. If the first network is a 5G network and the second network is a 6G network, or if the first network is a 6G network and the second network is a 5G network, then the first network device can be 5G+6G-AMF.

[0166] In some embodiments, similarly, the second network device can be the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed. If the first network is a 5G network and the second network is a 6G network, or if the first network is a 6G network and the second network is a 5G network, then the second network device can be 5G+6G-AMF.

[0167] For example, taking a first network as a 5G network and a second network as a 6G network, the first network device is a 5G+6G-AMF that supports both 5G and 6G networks, and the second network device is a 6G-AMF that only supports 6G; or, the first network device is a 5G-AMF that only supports 5G, and the second network device is a 5G+6G-AMF that supports both 5G and 6G networks; or, both the first and second network devices are 5G+6G-AMF that support both 5G and 6G networks; or, the core network devices of the first RAT and the second RAT are centrally deployed on the same network device, which is a 5G+6G-AMF that supports both 5G and 6G networks.

[0168] In one possible communication scenario, the core network devices of the first RAT and the second RAT are centrally deployed on the same core network device. In this embodiment, the core network device is referred to as the second network device. That is, the terminal device can access the first network by registering to the second network device, and similarly, the terminal device can also access the second network by registering to the second network device.

[0169] In some implementations, the terminal device receives a third identifier sent by the second network device; wherein the third identifier is carried in the registration acceptance message sent by the second network device to the terminal device, and the third identifier is a temporary identifier used by the terminal device during the first RAT and the second RAT.

[0170] In some embodiments, it is assumed that the second network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed. Therefore, the third identifier can be used in the implementation process of the first RAT and the second RAT.

[0171] In some embodiments, the third identifier can be GUTI. If the first network is a 5G network and the second network is a 6G network, then the third identifier does not need to distinguish between 5G and 6G, and in this case, the third identifier is GUTI.

[0172] In some embodiments, since the terminal device accesses both the first and second networks through the second network device, referring to the complete steps of the terminal device registering with the first network device in Figure 7, when the terminal device registers with the second network device to access the first network, it first sends a registration request message to the second network device. Then, after receiving the registration request message from the terminal device, the second network device triggers an authentication process. At this time, the second network device sends a security mode command message to the terminal device. The terminal device returns a security mode completion message to the second network device according to the security mode command message, thus completing the authentication. The second network device then sends a registration acceptance message to the terminal device. Simultaneously, the registration acceptance message may carry first information indicating that the terminal device's registration on the first network is valid. Finally, after receiving the registration acceptance message, the terminal device returns a registration completion message to the second network device to confirm that the terminal device's registration on the second network device is effective. Thus, the terminal device accesses the first network.

[0173] In some embodiments, after a terminal device accesses the first network by registering with a second network device, it can also access the second network by registering with the second network device. Referring to the steps of the terminal device registering with the second network device in Figure 9, when the terminal device registers with the second network device to access the second network, it first sends a registration request message to the second network device. Then, after receiving the registration request message from the terminal device, since the second network device is also the device used by the terminal device to access the first network, there is no need to execute the interaction process between the first network device and the second network device in Figure 9. The second network device can directly send a registration acceptance message to the terminal device. After receiving the registration acceptance message, the terminal device returns a registration completion message to the second network device to confirm that the registration of the terminal device on the second network device is effective. Thus, the terminal device accesses the second network.

[0174] In some implementations, the terminal device sends a registration request message to the second network device; receives a registration acceptance message from the second network device; and sends a registration completion message to the second network device; wherein the first information is carried in the registration acceptance message received by the terminal device from the second network device.

[0175] In some embodiments, the first network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed. However, due to the change of the location of the terminal device, another core network device can be switched to serve the terminal device, namely the second network device. At this time, assuming that the terminal device is currently connected to the second network, the second network reassigns a second network device to the terminal device due to the movement of the terminal device. The second network device is also a core network device that can simultaneously support the core network devices of the first RAT and the second RAT. At this time, the terminal device needs to reconnect to the second network by registering to the reassigned second network device.

[0176] In some implementations, the terminal device sends a third identifier to the second network device; wherein the third identifier is carried in the registration request message sent by the terminal device to the second network device, and the third identifier is a temporary identifier used by the terminal device during the first RAT and the second RAT.

[0177] In some embodiments, since the first network device assigns a third identifier to the terminal device when the terminal device registers with the first network device, the terminal device can still use the third identifier to implement the first RAT and the second RAT when switching from the first network device to the second network device. Based on this, the terminal device sends the third identifier to the second network device through a registration request message.

[0178] In some embodiments, the registration request message sent by the terminal device to the second network device may carry the UE identity number (ID), which may be SUCI or 5G-GUTI, as well as the registration type - initial registration or mobility update registration, and UE security capabilities.

[0179] In some embodiments, in addition to carrying the third identifier and the first information, the registration acceptance message sent by the second network device to the terminal device may also carry information such as the registration area and the available network slice (Allowed NSSAI).

[0180] In summary, according to the communication method of the embodiments of this application, the terminal device can select whether to send a service request message or a mobility registration request message when moving to a first network based on the first information. This method can avoid the need for the terminal device to have dual radios to support the movement of the terminal device under different networks, thereby saving signaling.

[0181] Based on the above embodiments, the communication method of the present application embodiment is described in detail below from the perspective of the first network device with reference to FIG10.

[0182] Figure 10 illustrates a communication method provided in an embodiment of this application, applied to a first network device. The method may include:

[0183] S1000, Send first information to the terminal device; wherein, the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used for the terminal device to send a service request message or a mobility registration request message.

[0184] In some embodiments, a first network device sends first information to a terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on a first network; the mobility registration result of the terminal device on the first network is used by the terminal device to send a service request message or a mobility registration request message.

[0185] In some embodiments, the first network device sends first information to the terminal device. After receiving the first information, the terminal device can determine whether to send a service request message or a mobility registration request message on the first network when accessing the first network, based on the mobility registration result of the terminal device on the first network indicated by the first information.

[0186] In some embodiments, the first information may include, but is not limited to, the registration result. In this application, the "Registration Result" field, which represents the first information, is given a meaning different from that in related technologies, for example, by adding a new value for this field.

[0187] In other embodiments, the first information may be represented by other fields, or a new field may be added to represent the first information. This embodiment does not limit this.

[0188] In some embodiments, the first information indicates the mobility registration result of the terminal device. In one embodiment, the mobility registration result of the terminal device includes at least one of the following: the mobility registration result of the terminal device on a first network; the mobility registration result of the terminal device on a second network. In one embodiment, the name of the first information is not specifically limited, such as registration result indication, registration validity indication, etc. In one example, the first information can be a "Registration Result" field. This field can be carried in a registration acceptance message or a registration rejection message during the registration process.

[0189] In some embodiments, the first information indicates the mobility registration result of the terminal device, which can be understood as the result of the terminal device's previous mobility registration.

[0190] In some implementations, the mobility registration result of the terminal device on the first network includes one of the following: the registration of the terminal device on the first network is valid; or the registration of the terminal device on the first network is invalid.

[0191] In some embodiments, the first network may be a radio access network employing a first RAT. The first RAT may include, but is not limited to, 5G or 6G, and correspondingly, the first network may be a 5G network or a 6G network. The specific first network can be determined according to actual circumstances, and this application does not limit it.

[0192] In some embodiments, valid registration of the terminal device on the first network can be understood as the terminal device's registration on the first network being available, or it can also be understood as the terminal device's UE context being available in the first network.

[0193] In some embodiments, invalid registration of the terminal device on the first network can be understood as the terminal device being unavailable for registration on the first network, or it can also be understood as the UE context of the terminal device being unavailable in the first network.

[0194] In some implementations, the terminal device can determine, based on the first information, that its registration on the first network is valid and its registration on the second network is valid; or, the terminal device can determine, based on the first information, that its registration on the first network is valid and its registration on the second network is invalid; or, the terminal device can determine, based on the first information, that its registration on the first network is invalid and its registration on the second network is valid.

[0195] In some embodiments, the second network uses a different RAT than the first network; in other words, the first network and the second network are networks using different RATs. In one embodiment, the second network can be a network using a second RAT. The second RAT can include, but is not limited to, 5G or 6G. Accordingly, the second network can be, but is not limited to, a 5G network or a 6G network. The specific second network can be determined according to actual circumstances, and this application embodiment does not limit it.

[0196] For example, the first network can be a 5G network and the second network can be a 6G network. In one example, the first network can be a 6G network and the second network can be a 5G network. The specific first and second networks can be determined according to the actual situation, and this application does not limit them.

[0197] In some embodiments, if the registration of the terminal device on the first network is invalid, the first information may directly indicate that the registration on the first network is invalid, or it may indicate that the registration of the terminal device is valid only on other networks (e.g., the second network), so that the terminal device can determine that the registration on the first network is invalid based on the first information.

[0198] For example, the first information indicates that the terminal device's registration is valid on both the first network and the second network (e.g., the terminal device's registration is 5G and 6G, referred to as 5G+6G), or the first information indicates that the terminal device's registration is valid only on the first network (e.g., the terminal device's registration is only on 5G, referred to as 5G only), or the first information indicates that the terminal device's registration is valid only on the second network (e.g., the terminal device's registration is only on 6G, referred to as 6G only).

[0199] In some embodiments, if the first information is used to indicate that the terminal device’s registration on the first network is valid, or to indicate that the terminal device’s registration on the first network is available, or to indicate that the terminal device’s context in the first network is available, the terminal device can directly access the first network using the first RAT, thereby the terminal device sends a service request message on the first network.

[0200] In some embodiments, if the first information sent by the first network device to the terminal device indicates that the terminal device's registration on the first network is invalid, then after receiving the first information, when the terminal device accesses the first network, it needs to send a mobility registration request message on the first network. Based on this, the terminal device needs to request successful registration from the first network through the mobility registration request message before it can access the first network.

[0201] In some embodiments, the first network device is the core network device of the first RAT, that is, the first network device can be a core network device that adopts the first RAT.

[0202] In some embodiments, the first network device may also be a core network device of a centrally deployed first RAT and a core network device of a second RAT; that is, the first network device may be a device that has deployed core network devices using the first RAT and core network devices using the second RAT. In this case, the core network devices of the first RAT and the second RAT are centrally deployed in the first network device.

[0203] In one possible communication scenario, the first network device is the core network device of the first RAT, that is, the core network device of the first RAT and the core network device of the second RAT are two independently deployed network devices. The terminal device needs to register with the first network device to access the first network. Similarly, the terminal device also needs to register with the second network device to access the second network.

[0204] In some implementations, the first network device receives a registration request message sent by the terminal device; sends a registration acceptance message to the terminal device; and receives a registration completion message sent by the terminal device; wherein the first information is carried in the registration acceptance message sent by the first network device to the terminal device.

[0205] In some embodiments, the terminal device needs to register with the first network device to access the first network. Referring to Figure 6, the specific registration process includes: after receiving the registration request message, the first network device sends a registration acceptance message to the terminal device. At the same time, the registration acceptance message may carry first information to indicate that the terminal device is validly registered on the first network. Finally, after receiving the registration acceptance message, the terminal device returns a registration completion message to the first network device to confirm that the registration of the terminal device on the first network device is effective. Thus, the terminal device accesses the first network.

[0206] In some embodiments, the first information carried in the registration acceptance message sent to the terminal device may only indicate that the terminal device's registration is valid on the first network. For example, if the first network is a 5G network, the first information indicates 5G only.

[0207] In some implementations, the first network device sends a first identifier to the terminal device; wherein the first identifier is carried in the registration acceptance message sent by the first network device to the terminal device, and the first identifier is a temporary identifier used by the terminal device in the first RAT.

[0208] In some embodiments, if the first network is a 5G network and the first network device is a core network device in the 5G network, then the first identifier is 5G-GUTI; if the first network is a 6G network and the first network device is a core network device in the 6G network, then the first identifier is 6G-GUTI.

[0209] In some embodiments, referring to FIG7, after receiving a registration request message from a terminal device, the first network device triggers an authentication process. At this time, the first network device sends a security mode command message to the terminal device. The terminal device returns a security mode completion message to the first network device according to the security mode command message. Thus, authentication is completed. The first network device can then send a registration acceptance message to the terminal device. After receiving the registration acceptance message, the terminal device returns a registration completion message to the first network device to confirm that the registration of the terminal device on the first network device is effective. Thus, the terminal device accesses the first network.

[0210] In some embodiments, the first network device receives a registration request message sent by the terminal device, which carries a UE identity number (ID). The UE ID can be SUCI or GUTI, and the registration type is either initial registration or mobility update registration, as well as the UE security capabilities.

[0211] In some embodiments, the Security Mode Command message is a Security Mode Command message. The Security Mode Command message carries the index information of the security key, also known as the Key Set Identifier (KSI), UE security capabilities, integrity algorithm, ciphering algorithm, and Initial NAS message request indication.

[0212] In some embodiments, the Security Mode Complete message is a Security Mode Complete message. This message carries a registration request message sent by the second network device to the terminal device. The registration request message may carry information such as the registration type, a first identifier, UE capability information, and the requested network slice (Requested NSSAI). The registration type can be mobility management registration or mobility registration for 5G to 6G transition.

[0213] In some embodiments, in addition to carrying the first identifier and the first information, the registration acceptance message sent by the first network device to the terminal device may also carry information such as the registration area and the available network slice (Allowed NSSAI).

[0214] In some implementations, it is assumed that the first network device is the core network device of the first RAT, that is, the core network device of the first RAT and the core network device of the second RAT are two independently deployed network devices. The first network device receives a context request message sent by the second network device; wherein, the context request message carries a registration request message sent by the terminal device to the second network device; sends a context response message to the second network device; and receives a context confirmation message sent by the second network device.

[0215] In some embodiments, after a terminal device registers with a first network device, if it needs to register with a second network device, referring to FIG9, the terminal device sends a registration request message to the second network device. The registration request message carries a first identifier corresponding to the first network device. Based on this, the second network device determines the first network device according to the first identifier and sends a context request message to the first network device. The first network device returns a context response message to the second network device according to the context request message. After receiving the context response message, the second network device sends a context confirmation message to the first network device. Finally, the second network device sends a registration acceptance message to the terminal device. After receiving the registration acceptance message, the terminal device returns a registration completion message to the second network device to confirm that the registration of the terminal device on the second network device is effective. Thus, the terminal device accesses the second network.

[0216] In some embodiments, the registration request message sent by the terminal device to the second network device may carry information such as registration type, first identifier, UE capability information, and requested network slice (Requested NSSAI). The registration type may be mobility management registration or mobility registration for 5G to 6G transition.

[0217] For example, the context request message can be a Namf_Communication_UEContext Transfer Request message.

[0218] For example, the context response message can be a Namf_Communication_UEContext Transfer Response message. The Namf_Communication_UEContext Transfer Response message can carry the UE context, including security context, PDU session information (PDU session ID), single network slice selection assistance, SMF information corresponding to each PDU session control, Allowed NSSAI, and UE capability information.

[0219] For example, the context acknowledgment message can be the Namf_Communication_UEContext Transfer Ack message.

[0220] In some implementations, the first network device sends capability information to the second network device; wherein the capability information indicates the first network device's ability to retain context; the capability information is carried in a context response message.

[0221] In some embodiments, the first network device may carry information about its ability to retain context in the context response message sent to the second network device. In this way, the second network device can return a context confirmation message to the first network device based on the first network device's capability information.

[0222] In some implementations, the first network device receives indication information sent by the second network device; wherein the indication information is used by the first network device to determine whether to retain the session list; the indication information is carried in a context confirmation message sent by the second network device to the first network device.

[0223] In some implementations, the first network device is the core network device of the first RAT, and at least supports the ability to retain context when the terminal moves to the second network; wherein the first network uses the first RAT and the second network uses the second RAT.

[0224] In some embodiments, since the first network device has the ability to retain the context of the terminal device on the first network after the terminal device accesses the second network from the first network, the first network device can retain the registration information of the terminal device on the first network. Therefore, the first message sent by the first network device to the terminal device can indicate that the terminal device's registration on the first network is valid (or optionally indicate that the registration is invalid). Based on this, when the terminal device re-accesses the first network, it can choose to send a service request message or a mobility registration request message according to the first message. For example, if the terminal device receives the first message from the second network device indicating that its registration on the first network is valid after moving from the first network to the second network, it can send a service request message on the first network when subsequently re-accessing the first network. Based on this, the terminal device can directly access the first network using the first RAT.

[0225] In some embodiments, the first network device is the core network device of the first RAT.

[0226] In some embodiments, if the first RAT is 5G and the first network is a 5G network, then the first network device can be a 5G-AMF; if the first RAT is 6G and the first network is a 6G network, then the first network device can be a 6G-AMF.

[0227] For example, when a terminal device accesses a 6G network from a 5G network, since the 5G-AMF corresponding to the 5G network has the ability to retain context, the registration information of the terminal device on the 5G network can be retained. Based on this, if the first information indicates that the registration of the terminal device on the 5G network is valid, when the terminal device re-accesses the 5G network, the terminal device can choose to directly access the 5G network without registering again.

[0228] In summary, according to the communication method of the embodiments of this application, the first network device sends first information to the terminal device so that the terminal device can select whether to send a service request message or a mobility registration request message when moving to the first network based on the first information. This method can avoid the need for the terminal device to have dual radios to support the movement of the terminal device under different networks, thereby saving signaling.

[0229] Based on the above embodiments, the communication method of the present application embodiment is described in detail below from the perspective of the second network device with reference to FIG11.

[0230] Figure 11 illustrates a communication method provided in an embodiment of this application, applied to a second network device. The method may include:

[0231] S1100, Send first information to the terminal device; wherein, the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used for the terminal device to send a service request message or a mobility registration request message.

[0232] In some embodiments, the second network device sends first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used for the terminal device to send a service request message or a mobility registration request message.

[0233] In some embodiments, the second network device sends first information to the terminal device. After receiving the first information, the terminal device can determine whether to send a service request message or a mobility registration request message on the first network when accessing the first network, based on the mobility registration result of the terminal device on the first network indicated by the first information.

[0234] In some embodiments, the first information may include, but is not limited to, the registration result. In this application, the "Registration Result" field, which represents the first information, is given a meaning different from that in related technologies, for example, by adding a new value for this field.

[0235] In other embodiments, the first information may be represented by other fields, or a new field may be added to represent the first information. This embodiment does not limit this.

[0236] In some embodiments, the first information indicates the mobility registration result of the terminal device. In one embodiment, the mobility registration result of the terminal device includes at least one of the following: the mobility registration result of the terminal device on a first network; the mobility registration result of the terminal device on a second network. In one embodiment, the name of the first information is not specifically limited, such as registration result indication, registration validity indication, etc. In one example, the first information can be a "Registration Result" field. This field can be carried in a registration acceptance message or a registration rejection message during the registration process.

[0237] In some embodiments, the first information indicates the mobility registration result of the terminal device, which can be understood as the result of the terminal device's previous mobility registration.

[0238] In some implementations, the mobility registration result of the terminal device on the first network includes one of the following: the registration of the terminal device on the first network is valid; or the registration of the terminal device on the first network is invalid.

[0239] In some embodiments, the first network may be a radio access network employing a first RAT. The first RAT may include, but is not limited to, 5G or 6G, and correspondingly, the first network may be a 5G network or a 6G network. The specific first network can be determined according to actual circumstances, and this application does not limit it.

[0240] In some embodiments, valid registration of the terminal device on the first network can be understood as the terminal device's registration on the first network being available, or it can also be understood as the terminal device's UE context being available in the first network.

[0241] In some embodiments, invalid registration of the terminal device on the first network can be understood as the terminal device being unavailable for registration on the first network, or it can also be understood as the UE context of the terminal device being unavailable in the first network.

[0242] In some implementations, based on the first information, it can be further determined that the terminal device's registration on the first network is valid and its registration on the second network is valid; or, the terminal device's registration on the first network is valid and its registration on the second network is invalid; or, the terminal device's registration on the first network is invalid and its registration on the second network is valid.

[0243] In some embodiments, the second network uses a different Radio Access Network (RAT) than the first network. The second network can be a radio access network using a second RAT. The second RAT can be, but is not limited to, 5G or 6G; correspondingly, the second network can be a 5G network or a 6G network. The specific second network can be determined according to actual circumstances, and this application does not limit it.

[0244] In other words, the first network and the second network are different networks using different RATs. For example, the first network can be a 5G network and the second network can be a 6G network; or, the first network can be a 6G network and the second network can be a 5G network. The specific first and second networks can be determined according to the actual situation, and this application does not limit them.

[0245] In some embodiments, when the first information indicates that the registration of the terminal device on the first network is invalid, it may directly indicate that the registration on the first network is invalid, or it may indicate that the registration of the terminal device is valid only on other networks (such as the second network), so that the terminal device can determine that the registration on the first network is invalid based on the first information.

[0246] For example, the first information indicates that the terminal device's registration is valid on both the first network and the second network (e.g., 5G+6G), or the first information indicates that the terminal device's registration is valid only on the first network (e.g., 5G only), or the first information indicates that the terminal device's registration is valid only on the second network (e.g., 6G only).

[0247] In some embodiments, the first information indicates the mobility registration result of the terminal device on the first network, which can be understood as the registration result of the terminal device's previous mobility registration with the first network.

[0248] In some embodiments, if the first information is used to indicate that the terminal device’s registration on the first network is valid, or to indicate that the terminal device’s registration on the first network is available, or to indicate that the terminal device’s context in the first network is available, the terminal device can directly access the first network using the first RAT, thereby the terminal device sends a service request message on the first network.

[0249] In some embodiments, if the first information sent by the second network device to the terminal device indicates that the terminal device's registration on the first network is invalid, then after receiving the first information, when the terminal device accesses the first network, it needs to send a mobility registration request message on the first network. Based on this, the terminal device needs to request successful registration from the first network through the mobility registration request message before it can access the first network.

[0250] In some implementations, the first network device is the core network device of the first RAT, and at least supports the ability to retain context when the terminal moves to the second network; wherein the first network uses the first RAT and the second network uses the second RAT.

[0251] In some embodiments, since the first network device has the ability to retain the context of the terminal device on the first network after the terminal device accesses the second network from the first network, the first network device can retain the registration information of the terminal device on the first network. Therefore, the first message sent by the first network device to the terminal device can indicate that the terminal device's registration on the first network is valid (or optionally indicate that the registration is invalid). Based on this, when the terminal device re-accesses the first network, it can choose to send a service request message or a mobility registration request message according to the first message. For example, if the terminal device receives the first message from the second network device indicating that its registration on the first network is valid after moving from the first network to the second network, it can send a service request message on the first network when subsequently re-accessing the first network. Based on this, the terminal device can directly access the first network using the first RAT.

[0252] In some embodiments, the first network device is the core network device of the first RAT.

[0253] In some embodiments, if the first RAT is 5G and the first network is a 5G network, then the first network device can be a 5G-AMF; if the first RAT is 6G and the first network is a 6G network, then the first network device can be a 6G-AMF.

[0254] For example, when a terminal device accesses a 6G network from a 5G network, since the 5G-AMF corresponding to the 5G network has the ability to retain context, the registration information of the terminal device on the 5G network can be retained. Based on this, if the first information indicates that the registration of the terminal device on the 5G network is valid, when the terminal device re-accesses the 5G network, the terminal device can choose to directly access the 5G without registering again.

[0255] In some embodiments, the second network device is the core network device of the second RAT, that is, the second network device can be a core network device that adopts the second RAT.

[0256] In some embodiments, the second network device may also be a core network device of both the first RAT and the second RAT deployed in a centralized manner; that is, the second network device may be a device that has deployed core network devices using both the first and second RATs. In this case, the core network devices of the first and second RATs are centrally deployed in the second network device.

[0257] In one possible communication scenario, the second network device is the core network device of the second RAT. That is, the core network device of the first RAT and the core network device of the second RAT are two independently deployed network devices. The terminal device needs to register with the first network device to access the first network. Similarly, the terminal device also needs to register with the second network device to access the second network.

[0258] In some embodiments, the second network device may further perform the following steps: receiving a registration request message sent by the terminal device; sending a context request message to the first network device; wherein the context request message carries the registration request message; receiving a context response message sent by the first network device; sending a context confirmation message to the first network device; sending an update request message to the third network device; receiving an update response message sent by the third network device; sending a registration acceptance message to the terminal device; and receiving a registration completion message sent by the terminal device; wherein the first information is carried in the registration acceptance message sent by the second network device to the terminal device.

[0259] In some embodiments, the terminal device needs to register with the second network device to access the first network. Referring to Figure 9, the specific registration process includes: First, the terminal device needs to send a registration request message to the second network device. The registration request message carries a first identifier corresponding to the first network device. Based on this, the second network device can determine the first network device according to the first identifier, and then send a context request message to the first network device. The first network device returns a context response message to the second network device according to the context request message. After receiving the context response message, the second network device sends a context confirmation message to the first network device. Finally, the second network device sends a registration acceptance message to the terminal device. After receiving the registration acceptance message, the terminal device returns a registration completion message to the second network device to confirm that the registration of the terminal device on the second network device is effective. Thus, the terminal device accesses the second network.

[0260] In some embodiments, the registration request message received by the second network device from the terminal device may carry information such as registration type, first identifier, UE capability information, and requested network slice (Requested NSSAI). The registration type may be mobility management registration or mobility registration for 5G to 6G transition.

[0261] For example, the context request message can be a Namf_Communication_UEContext Transfer Request message.

[0262] For example, the context response message can be a Namf_Communication_UEContext Transfer Response message. The Namf_Communication_UEContext Transfer Response message can carry the UE context, including security context, PDU session information (PDU session ID), single network slice selection assistance, SMF information corresponding to each PDU session control, Allowed NSSAI, and UE capability information.

[0263] For example, the context acknowledgment message can be the Namf_Communication_UEContext Transfer Ack message.

[0264] In some embodiments, the registration acceptance message sent by the second network device to the terminal device may carry information such as the registration area and the available network slice (Allowed NSSAI) in addition to the second identifier and the first information.

[0265] In some embodiments, referring to FIG12, after the second network device sends a context confirmation message to the first network device, it also needs to send an update request message to the third network device, such as Nsmf_PDUSession_UpdateSMContext Request, to request network changes from the third network device. After receiving the update request message sent by the second network device, the third network device can return an update response message to the second network device, such as Nsmf_PDUSession_UpdateSMContext Response, that is, respond to the network changes made by the second network device for the terminal device.

[0266] For example, the third network device can be an SMF that supports both the first network and the second network. If the first network and the second network are 5G and 6G networks respectively, then the third network device is an SMF that supports both 5G-AMF and 6G-AMF, such as 5G+6G-SMF.

[0267] In some embodiments, after receiving the update response message sent by the third network device, the second network device may respond to the registration request message sent by the terminal device and return a registration acceptance message to the terminal device. After receiving the registration acceptance message, the terminal device sends a registration completion message to the second network device. At this point, the registration of the terminal device on the second network device is completed, and the terminal device accesses the second network.

[0268] In some embodiments, the second network device may carry first information in the registration acceptance message sent to the terminal device to indicate whether the registration of the terminal device on the first network is valid.

[0269] For example, the first information may indicate that the registration of the terminal device on the second network device is valid while the registration on the first network device is also valid, or the first information may indicate that the registration of the terminal device is valid only on the second network device.

[0270] In some embodiments, the first information carried in the registration acceptance message sent by the second network device to the terminal device may only indicate that the terminal device's registration is valid on the second network. For example, if the second network is a 6G network, the first information indicates 6G only. Alternatively, the first information may indicate that the terminal device's registration is valid on both the first and second networks, meaning it indicates that the terminal device's registration is valid on both networks. For example, if the first network is a 5G network and the second network is a 6G network, the first information indicates 5G+6G.

[0271] In some implementations, the second network device receives a first identifier sent by the terminal device; wherein the first identifier is carried in the registration request message sent by the terminal device to the second network device, and the first identifier is a temporary identifier used by the terminal device in the first RAT.

[0272] In some implementations, the second network device identifies the first network device based on the first identifier.

[0273] In some embodiments, the terminal device may send the first identifier in the registration request message to the second network device. Thus, after receiving the registration request message, the second network device can identify the first network device based on the first identifier and send a context request message to the first network device to determine whether the first network device has the ability to retain context.

[0274] For example, the first network is a 5G network, the first network device is a 5G-AMF, and the first identifier is a 5G-GUTI. The second network is a 6G network, and the second network device is a 6G-AMF. After receiving the 5G-GUTI sent by the terminal device, the 6G-AMF can determine the 5G-AMF based on the 5G-GUTI and then send a Namf_Communication_UEContext Transfer Request to the 5G-AMF.

[0275] For example, the first network is a 6G network, the first network device is a 6G-AMF, and the first identifier is a 6G-GUTI. The second network is a 5G network, and the second network device is a 5G-AMF. After receiving the 6G-GUTI sent by the terminal device, the 5G-AMF can determine the 6G-AMF based on the 6G-GUTI and then send a Namf_Communication_UEContext Transfer Request to the 6G-AMF.

[0276] In some embodiments, the registration request message received by the second network device from the terminal device may carry information such as registration type, first identifier, UE capability information, and requested network slice (Requested NSSAI). The registration type may be mobility management registration or mobility registration for 5G to 6G transition.

[0277] For example, the context request message can be a Namf_Communication_UEContext Transfer Request message.

[0278] For example, the context response message can be a Namf_Communication_UEContext Transfer Response message. The Namf_Communication_UEContext Transfer Response message can carry the UE context, including security context, PDU session information (PDU session ID), single network slice selection assistance, SMF information corresponding to each PDU session control, Allowed NSSAI, and UE capability information.

[0279] For example, the context acknowledgment message can be the Namf_Communication_UEContext Transfer Ack message.

[0280] In some embodiments, the registration acceptance message sent by the second network device to the terminal device may carry information such as the registration area and the available network slice (Allowed NSSAI) in addition to the second identifier and the first information.

[0281] In some implementations, the second network device receives capability information sent by the first network device; wherein the capability information indicates the first network device's ability to retain context; the capability information is carried in a context response message.

[0282] In some embodiments, after the second network device sends a context request message to the first network device, the first network device may return a context response message to the second network device. The context response message may carry capability information of the first network device to indicate whether the first network device has the capability to retain context.

[0283] In some implementations, the second network device acquires capability information; wherein the capability information indicates the first network device's ability to retain context.

[0284] In some embodiments, capability information may be obtained without using context response messages. The second network device may interact with the first network device separately through other signaling to obtain the capability information of the first network device.

[0285] In some implementations, the second network device sends indication information to the first network device; wherein the indication information is used by the first network device to determine whether to retain the session list; the indication information is carried in a context confirmation message.

[0286] In some embodiments, after obtaining the capability information of the first network device, the second network device can generate indication information based on the capability information. That is, it can generate indication information to indicate whether the first network device should retain the session list based on whether the first network device has the capability to retain the context, and carry it in the context confirmation message and return it to the first network device.

[0287] In some implementations, the second network device determines, based on capability information, that the first network device does not have the capability to retain context; and determines indication information for the first network device to determine whether to retain the session list.

[0288] In some embodiments, if the capability information of the first network device indicates that the first network device does not have the capability to retain context, the second network device may carry indication information in the context confirmation message sent to the first network device. This indication information is used to indicate that the session list on the first network device is not retained, that is, the registration of the terminal device on the first network device is not retained.

[0289] In some implementations, the second network device determines, based on capability information, that the first network device has the capability to retain context; determines indication information for the first network device to determine not to retain the session list; or determines indication information for the first network device to determine to retain the session list.

[0290] In some embodiments, if the capability information of the first network device indicates that the first network device has the capability to retain context, the second network device may carry indication information in the context confirmation message sent to the first network device. This indication information is used to indicate the session list to be retained on the first network device, that is, the registration of the terminal device on the first network device can be retained.

[0291] In some embodiments, even if the capability information of the first network device indicates that the first network device has the ability to retain context, the second network device may choose not to retain the registration of the terminal device on the first network device. That is, the context confirmation message sent to the first network device carries indication information for indicating that the session list on the first network device is not retained. In other words, the registration of the terminal device on the first network device is not retained.

[0292] In some implementations, the second network device sends a type indication message to the third network device; wherein the type indication message is used to indicate the supported RAT types; the type indication message is carried in the update request message.

[0293] In some embodiments, when the second network device sends an update request message to the third network device, it may include a type indication message indicating the supported RAT type in the update request message before sending the update request message to the third network device.

[0294] For example, if the first network device is 5G-AMF and the second network device is 6G-AMF, then the type indication message (RAT type) can be 5G+6G-RAN, indicating that both 5G and 6G are supported at the same time, or the type indication message (RAT type) can be 6G-RAN, indicating that only 6G is supported at the same time.

[0295] For example, if the first network device is 6G-AMF and the second network device is 5G-AMF, then the type indication message (RAT type) can be 5G+6G-RAN, indicating that both 5G and 6G are supported at the same time, or the type indication message (RAT type) can be 5G-RAN, indicating that only 5G is supported at the same time.

[0296] In some implementations, the second network device receives a type confirmation message sent by the third network device; wherein the type confirmation message is used to indicate whether the registration of the first network is available; the type confirmation message is carried in the update response message.

[0297] In some embodiments, after receiving an update request message from a second network device, the third network device may include a type confirmation message indicating whether the registration of the first network is available in the update response message, and then send the update response message to the second network device.

[0298] In some embodiments, if the type indication message is 6G-RAN, then the type confirmation message confirms that only 6G-RAN is available; if the type indication message is 5G+6G-RAN, then the type confirmation message confirms that both 5G-RAN and 6G-RAN are available.

[0299] In some implementations, the second network device sends a second identifier to the terminal device; wherein the second identifier is carried in the registration acceptance message sent by the second network device to the terminal device, and the second identifier is a temporary identifier used by the terminal device in the second RAT.

[0300] In some embodiments, after registering with the terminal device, the first network device may carry a second identifier in the registration acceptance message sent to the terminal device. The second identifier may be a GUTI. If the second network is a 5G network and the second network device is a core network device in the 5G network, then the second identifier is 5G-GUTI. If the second network is a 6G network and the second network device is a core network device in the 6G network, then the second identifier is 6G-GUTI.

[0301] In some implementations, the first network device is a core network device supporting a centralized deployment of a first RAT and a second RAT; and / or, the second network device is a core network device supporting a centralized deployment of a first RAT and a second RAT.

[0302] In some embodiments, the first network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed. If the first network is a 5G network and the second network is a 6G network, or if the first network is a 6G network and the second network is a 5G network, then the first network device can be 5G+6G-AMF.

[0303] In some embodiments, similarly, the second network device can be the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed. If the first network is a 5G network and the second network is a 6G network, or if the first network is a 6G network and the second network is a 5G network, then the second network device can be 5G+6G-AMF.

[0304] For example, taking a first network as a 5G network and a second network as a 6G network, the first network device is a 5G+6G-AMF that supports both 5G and 6G networks, and the second network device is a 6G-AMF that only supports 6G; or, the first network device is a 5G-AMF that only supports 5G, and the second network device is a 5G+6G-AMF that supports both 5G and 6G networks; or, both the first and second network devices are 5G+6G-AMF that support both 5G and 6G networks; or, the core network devices of the first RAT and the second RAT are centrally deployed on the same network device, which is a 5G+6G-AMF that supports both 5G and 6G networks.

[0305] In some implementations, the second network device may also perform the following steps: receiving a registration request message sent by the terminal device; sending an update request message to the third network device; receiving an update response message sent by the third network device; sending a registration acceptance message to the terminal device; and receiving a registration completion message sent by the terminal device.

[0306] In some embodiments, the terminal device needs to register with the second network device to access the second network. The specific registration process includes: first, the terminal device sends a registration request message to the second network device; then, after receiving the registration request message, the second network device sends an update request message to the third network device, and after receiving the update response message sent by the third network device, sends a registration acceptance message to the terminal device. At the same time, the registration acceptance message may carry first information indicating that the terminal device's registration on the second network is valid; finally, after receiving the registration acceptance message, the terminal device returns a registration completion message to the second network device to confirm that the terminal device's registration on the second network device is effective.

[0307] In some embodiments, the first information carried in the registration acceptance message may only indicate that the terminal device's registration on the second network is valid, or the first information may indicate that the terminal device's registration on the second network is also valid while retaining the validity of the terminal device's registration on the first network. This can be understood as indicating that the terminal device's registration on both the first and second networks is valid.

[0308] In one possible communication scenario, the core network devices of the first RAT and the second RAT are centrally deployed on the same core network device. In this embodiment, the core network device is referred to as the second network device. That is, the terminal device can access the first network by registering to the second network device, and similarly, the terminal device can also access the second network by registering to the second network device.

[0309] In some implementations, the second network device sends a third identifier to the terminal device; wherein the third identifier is carried in the registration acceptance message sent by the second network device to the terminal device, and the third identifier is a temporary identifier used by the terminal device during the first RAT and the second RAT.

[0310] In some embodiments, it is assumed that the second network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed. Therefore, the third identifier can be used in the implementation process of the first RAT and the second RAT.

[0311] In some embodiments, the third identifier can be GUTI. If the first network is a 5G network and the second network is a 6G network, then the third identifier does not need to distinguish between 5G and 6G, and in this case, the third identifier is GUTI.

[0312] In some embodiments, since the terminal device accesses both the first and second networks through the second network device, referring to the complete steps of the terminal device registering with the first network device in Figure 7, when the terminal device registers with the second network device to access the first network, it first sends a registration request message to the second network device. Then, after receiving the registration request message from the terminal device, the second network device triggers an authentication process. At this time, the second network device sends a security mode command message to the terminal device. The terminal device returns a security mode completion message to the second network device according to the security mode command message, thus completing the authentication. The second network device then sends a registration acceptance message to the terminal device. Simultaneously, the registration acceptance message may carry first information indicating that the terminal device's registration on the first network is valid. Finally, after receiving the registration acceptance message, the terminal device returns a registration completion message to the second network device to confirm that the terminal device's registration on the second network device is effective. Thus, the terminal device accesses the first network.

[0313] In some embodiments, after a terminal device accesses the first network by registering with a second network device, it can also access the second network by registering with the second network device. Referring to the steps of the terminal device registering with the second network device in Figure 9, when the terminal device registers with the second network device to access the second network, it first sends a registration request message to the second network device. Then, after receiving the registration request message from the terminal device, since the second network device is also the device used by the terminal device to access the first network, there is no need to execute the interaction process between the first network device and the second network device in Figure 9. The second network device can directly send a registration acceptance message to the terminal device. After receiving the registration acceptance message, the terminal device returns a registration completion message to the second network device to confirm that the registration of the terminal device on the second network device is effective. Thus, the terminal device accesses the second network.

[0314] In some implementations, the second network device may further perform the following steps: receiving a registration request message sent by the terminal device; sending a registration acceptance message to the terminal device; receiving a registration completion message sent by the terminal device; wherein the first information is carried in the registration acceptance message sent by the second network device to the terminal device.

[0315] In some embodiments, the first network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed. However, due to the change of the location of the terminal device, another core network device can be switched to serve the terminal device, namely the second network device. At this time, assuming that the terminal device is currently connected to the second network, the second network reassigns a second network device to the terminal device due to the movement of the terminal device. The second network device is also a core network device that can simultaneously support the core network devices of the first RAT and the second RAT. At this time, the terminal device needs to reconnect to the second network by registering to the reassigned second network device.

[0316] In some implementations, the second network device receives a third identifier sent by the terminal device; wherein the third identifier is carried in the registration request message sent by the terminal device to the second network device, and the third identifier is a temporary identifier used by the terminal device during the first RAT and the second RAT.

[0317] In some embodiments, since the first network device assigns a third identifier to the terminal device when the terminal device registers with the first network device, the terminal device can still use the third identifier to implement the first RAT and the second RAT when switching from the first network device to the second network device. Based on this, the terminal device sends the third identifier to the second network device through a registration request message.

[0318] In some embodiments, the second network device may carry a UE identity number (ID) in the registration request message sent by the terminal device. The UE ID may be SUCI or 5G-GUTI, and the registration type may be initial registration or mobility update registration, as well as UE security capabilities.

[0319] In some embodiments, in addition to carrying a third identifier and first information, the registration acceptance message may also carry information such as the registration area and the available network slices (Allowed NSSAI).

[0320] In summary, according to the communication method of the embodiments of this application, the second network device sends first information to the terminal device so that the terminal device can select whether to send a service request message or a mobility registration request message when moving to the first network based on the first information. This method can avoid the need for the terminal device to have dual radios to support the movement of the terminal device under different networks, thereby saving signaling.

[0321] Based on the above embodiments, the communication method of the present application embodiment is described in detail below from the perspective of a third network device with reference to FIG13.

[0322] Figure 13 illustrates a communication method provided in an embodiment of this application, applied to a third network device. The method may include:

[0323] S1300, Send a type confirmation message to the second network device; wherein, the type confirmation message is used to indicate whether the first network is available.

[0324] In some embodiments, the third network device sends a type confirmation message to the second network device; wherein the type confirmation message is used to indicate whether the first network is available.

[0325] In some embodiments, the third network device is a device in the core network that simultaneously supports the first network device and the second network device.

[0326] For example, the third network device can be an SMF that simultaneously supports the first network device and the second network device. If the first network and the second network are 5G network and 6G network respectively, then the third network device is an SMF that supports both 5G-AMF and 6G-AMF, such as 5G+6G-SMF.

[0327] In some embodiments, a third network device may send a type confirmation message to a second network device to indicate whether registration with the first network is available.

[0328] In some embodiments, if the first network device is 5G-AMF and the second network device is 6G-AMF, then the type confirmation message can be used to confirm that only 6G-RAN is available, or to confirm that both 5G-RAN and 6G-RAN are available.

[0329] In some implementations, the third network device may further perform the following steps: receiving an update request message sent by the second network device; sending an update response message to the second network device; wherein the type confirmation message is carried in the update response message sent by the third network device to the second network device.

[0330] In some embodiments, after receiving an update request message from a second network device, the third network device may include a type confirmation message indicating whether the registration of the first network is available in the update response message, and then send the update response message to the second network device.

[0331] In some embodiments, referring to FIG12, after the second network device sends a context confirmation message to the first network device, it also needs to send an update request message to the third network device, such as Nsmf_PDUSession_UpdateSMContext Request, to request network changes from the third network device. After receiving the update request message sent by the second network device, the third network device can return an update response message to the second network device, such as Nsmf_PDUSession_UpdateSMContext Response, which is to respond to the network changes made by the second network device for the terminal device. After receiving the update response message sent by the third network device, the second network device can respond to the registration request message sent by the terminal device and return a registration acceptance message to the terminal device. After receiving the registration acceptance message, the terminal device sends a registration completion message to the second network device. At this point, the registration of the terminal device on the second network device is completed, and the terminal device accesses the second network.

[0332] In some implementations, the third network device receives type indication information sent by the second network device; wherein the type indication message is used to indicate the supported RAT type; the type indication message is carried in the update request message.

[0333] In some embodiments, when the second network device sends an update request message to the third network device, it may include a type indication message indicating the supported RAT type in the update request message before sending the update request message to the third network device.

[0334] For example, if the first network device is 5G-AMF and the second network device is 6G-AMF, then the type indication message (RAT type) can be 5G+6G-RAN, indicating that both 5G and 6G are supported at the same time, or the type indication message (RAT type) can be 6G-RAN, indicating that only 6G is supported at the same time.

[0335] For example, if the first network device is 6G-AMF and the second network device is 5G-AMF, then the type indication message (RAT type) can be 5G+6G-RAN, indicating that both 5G and 6G are supported at the same time, or the type indication message (RAT type) can be 5G-RAN, indicating that only 5G is supported at the same time.

[0336] In some embodiments, after receiving the type indication message sent by the second network device, the third network device can return a type confirmation message to the second network device according to the type indication message. If the type indication message is 6G-RAN, the type confirmation message confirms that only 6G-RAN is available. If the type indication message is 5G+6G-RAN, the type confirmation message confirms that both 5G-RAN and 6G-RAN are available.

[0337] In summary, according to the communication method of the embodiments of this application, the third network device sends a type confirmation message to the second network device to indicate whether the first network is available, so that the second network device sends first information to the terminal device, thereby enabling the terminal device to select whether to send a service request message or a mobility registration request message when moving to the first network based on the first information. This method can avoid the need for the terminal device to have dual radios to support the movement of the terminal device under different networks, thereby saving signaling.

[0338] Based on the above embodiments, the communication method of the present application embodiment has been described in detail above with reference to FIG5 from the perspective of the terminal device, FIG10 from the perspective of the first network device, FIG11 from the perspective of the second network device, and FIG13 from the perspective of the third network device. The communication method of the present application embodiment is described in detail below with reference to FIG14 from the perspective of the first communication system.

[0339] Figure 14 illustrates a communication method provided in an embodiment of this application, applied to a first communication system. The first communication system includes at least a second network device and a third network device. The method may include:

[0340] S1400, the second network device sends an update request message to the third network device; wherein, the update request message carries a type indication message, which is used to indicate the supported RAT types.

[0341] In some embodiments, the second network device sends an update request message to the third network device; wherein the update request message carries a type indication message, which is used to indicate the supported RAT types.

[0342] In some embodiments, the second network device may send an update request message, such as an Nsmf_PDUSession_UpdateSMContext Request, to the third network device to request network changes.

[0343] In some embodiments, when the second network device sends an update request message to the third network device, it may include a type indication message indicating the supported RAT type in the update request message before sending the update request message to the third network device.

[0344] For example, if the first network device is 5G-AMF and the second network device is 6G-AMF, then the type indication message (RAT type) can be 5G+6G-RAN, indicating that both 5G and 6G are supported at the same time, or the type indication message (RAT type) can be 6G-RAN, indicating that only 6G is supported at the same time.

[0345] For example, if the first network device is 6G-AMF and the second network device is 5G-AMF, then the type indication message (RAT type) can be 5G+6G-RAN, indicating that both 5G and 6G are supported at the same time, or the type indication message (RAT type) can be 5G-RAN, indicating that only 5G is supported at the same time.

[0346] S1401, the third network device sends an update response message to the second network device; wherein, the update response message carries a type confirmation message, which is used to indicate whether the first network is available.

[0347] In some embodiments, the third network device sends an update response message to the second network device; wherein the update response message carries a type confirmation message, which is used to indicate whether the first network is available; the first network uses a first RAT.

[0348] In some embodiments, after receiving an update request message sent by the second network device, the third network device may return an update response message to the second network device, such as an Nsmf_PDUSession_UpdateSMContext Response, which is a response to the network changes made by the second network device to the terminal device.

[0349] In some embodiments, after receiving an update request message from a second network device, the third network device may include a type confirmation message indicating whether the registration of the first network is available in the update response message, and then send the update response message to the second network device.

[0350] In some embodiments, if the type indication message is 6G-RAN, then the type confirmation message confirms that only 6G-RAN is available; if the type indication message is 5G+6G-RAN, then the type confirmation message confirms that both 5G-RAN and 6G-RAN are available.

[0351] In summary, according to the communication method of the embodiments of this application, the third network device sends a type confirmation message to the second network device to indicate whether the first network is available, so that the second network device sends first information to the terminal device, thereby enabling the terminal device to select whether to send a service request message or a mobility registration request message when moving to the first network based on the first information. This method can avoid the need for the terminal device to have dual radios to support the movement of the terminal device under different networks, thereby saving signaling.

[0352] Based on the above embodiments, the communication method of the present application embodiment has been described in detail above with reference to FIG5 from the perspective of the terminal device, FIG10 from the perspective of the first network device, FIG11 from the perspective of the second network device, and FIG13 from the perspective of the third network device. The communication method of the present application embodiment is described in detail below with reference to FIG15 from the perspective of the second communication system.

[0353] Figure 15 illustrates a communication method provided in an embodiment of this application, applied to a second communication system. The second communication system includes at least a terminal device and a second network device. The method may include:

[0354] S1500, the second network device sends first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network.

[0355] In some embodiments, the second network device sends first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; wherein the first network uses a first RAT.

[0356] In some embodiments, the second network device sends first information to the terminal device. After receiving the first information, the terminal device can determine whether to send a service request message or a mobility registration request message on the first network when accessing the first network, based on the mobility registration result of the terminal device on the first network indicated by the first information.

[0357] S1501. When the terminal device accesses the first network, it sends a service request message or a mobility registration request message on the first network.

[0358] In some embodiments, when a terminal device accesses a first network, it sends a service request message or a mobility registration request message on the first network based on the received first information.

[0359] In some embodiments, if the first information is used to indicate that the terminal device’s registration on the first network is valid, or to indicate that the terminal device’s registration on the first network is available, or to indicate that the terminal device’s context in the first network is available, the terminal device can directly access the first network using the first RAT, thereby the terminal device sends a service request message on the first network.

[0360] In some embodiments, if the first information sent by the second network device to the terminal device indicates that the terminal device's registration on the first network is invalid, then after receiving the first information, when the terminal device accesses the first network, it needs to send a mobility registration request message on the first network. Based on this, the terminal device needs to request successful registration from the first network through the mobility registration request message before it can access the first network.

[0361] In summary, according to the communication method of the embodiments of this application, the second network device can send first information to the terminal device. The terminal device can choose to send a service request message or a mobility registration request message when moving to the first network based on the first information. This method can avoid the need for the terminal device to have dual radios to support the movement of the terminal device under different networks, thereby saving signaling.

[0362] Based on the above embodiments, in order to facilitate understanding of the communication method provided in the embodiments of this application, the following describes possible implementation schemes of the communication method applicable to the embodiments of this application based on the interaction process between the terminal device and the first network device, the second network device and the third network device.

[0363] Example 1

[0364] In this embodiment, the first network device is the core network device of the first RAT, and the second network device is the core network device of the second RAT. At this time, the core network device of the first RAT and the core network device of the second RAT are two independently deployed network devices.

[0365] Step 1: The terminal device sends a registration request message to the first network device.

[0366] Optionally, if the first network is a 5G network, then the first network device is a 5G-AMF; if the first network is a 6G network, then the first network device is a 6G-AMF.

[0367] Step 2: The first network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a first identifier and first information. The first identifier is a temporary identifier used by the terminal device in the first RAT. The first information at least indicates the mobility registration result of the terminal device on the first network.

[0368] Optionally, if the first network is a 5G network, then the first identifier is 5G-GUTI; if the first network is a 6G network, then the first identifier is 6G-GUTI.

[0369] Optionally, since the terminal device is currently connected to the first network, the first information can indicate that the terminal device's registration on the currently connected first network is valid.

[0370] Step 3: The terminal device sends a registration completion message to the first network device.

[0371] Optionally, the registration completion message is used to confirm that the terminal device's registration on the first network device has taken effect, thereby making the first identifier effective.

[0372] Step 4: The terminal device selects the cell corresponding to the second network to access. At this time, the terminal device sends a registration request message to the second network device on the second network. The registration request message carries the first identifier.

[0373] Optionally, the terminal device may include a first identifier in the registration request message sent to the second network device, thereby allowing the second network device to determine that the terminal device has previously registered on the first network device based on the first identifier.

[0374] Optionally, if the second network is a 5G network, then the second network device is a 5G-AMF; if the second network is a 6G network, then the second network device is a 6G-AMF.

[0375] Step 5: The second network device determines the first network device based on the first identifier and sends a context request message to the first network device; wherein the context request message carries a registration request message.

[0376] Step 6: The first network device sends a context response message to the second network device. The context response message may carry the capability information of the first network device.

[0377] Optionally, the capability information here can indicate that the first network device has the ability to retain context. The capability information can also be obtained without using context response messages. The second network device can interact with the first network device separately through other signaling to obtain the capability information of the first network device.

[0378] Step 7: The second network device returns a context confirmation message to the first network device, which carries indication information.

[0379] Optionally, after obtaining the capability information of the first network device, the second network device can generate indication information based on the capability information. That is, it can generate indication information to instruct the first network device to retain the session list based on the first network device's ability to retain the context, and carry it in the context confirmation message and return it to the first network device.

[0380] Step 8: The second network device sends an update request message to the third network device, and the update request message carries a type indication message.

[0381] Optionally, when the second network device sends an update request message to the third network device, since the indication information instructs the first network device to retain the session list, the type indication message can be a type indication message that simultaneously supports the first RAT of the first network and the second RAT of the second network. For example, if the first network is a 5G network and the second network is a 6G network, then the type indication message is 5G+6G-RAN; or, the type indication message can be a type indication message that supports the second RAT of the second network, for example, the type indication message is 6G-RAN, but at the same time indicates that 5G-RAN is retained.

[0382] Step 9: The third network device sends an update response message to the second network device, and the update response message carries a type confirmation message.

[0383] Optionally, after receiving the update request message sent by the second network device, the third network device may include a type confirmation message indicating the availability of registration for the first network in the update response message. For example, if the first network is a 5G network and the second network is a 6G network, then the type confirmation message indicates that both 5G-RAN and 6G-RAN are available.

[0384] Step 10: The second network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a second identifier and first information. The second identifier is a temporary identifier used by the terminal device in the second RAT. The first information at least indicates that the terminal device's registration on the first network is valid.

[0385] Optionally, if the second network is a 5G network, then the second identifier is 5G-GUTI; if the second network is a 6G network, then the second identifier is 6G-GUTI.

[0386] Optionally, the first information sent by the second network device to the terminal device may instruct the terminal device to maintain its registration in the first network while its current registration in the second network is valid.

[0387] Step 11: The terminal device sends a registration completion message to the second network device.

[0388] Optionally, the registration completion message is used to confirm that the terminal device's registration on the second network device has taken effect, thereby making the second identifier effective.

[0389] Step 12: When the terminal device reconnects to the first network while in an idle state, since the first information sent in step 10 indicates that the terminal device's registration on the first network is valid while its registration on the second network is also valid, the terminal device only needs to send a service request message on the first network to directly access the first network using the first RAT.

[0390] Optionally, if the first network is a 5G network and the second network is a 6G network, when the terminal device accesses the 6G network and then the 5G network again, since the first information sent in step 10 indicates that the terminal device's registration on the 5G network is valid while its current registration on the 6G network is also valid, the terminal device only needs to send a service request message when accessing the 5G network to directly access the 5G network.

[0391] Optionally, if the first network is a 6G network and the second network is a 5G network, then when the terminal device accesses the 6G network, then the 5G network, and then the 6G network, since the first information sent in step 10 indicates that the terminal device's registration on the 6G network is valid while its current registration on the 5G network is also valid, the terminal device only needs to send a service request message when accessing the 6G network to directly access the 6G network.

[0392] Example 2

[0393] In this embodiment, the first network device is the core network device of the first RAT, and the second network device is the core network device of the second RAT. At this time, the core network device of the first RAT and the core network device of the second RAT are two independently deployed network devices.

[0394] Step 1: The terminal device sends a registration request message to the first network device.

[0395] Optionally, if the first network is a 5G network, then the first network device is a 5G-AMF; if the first network is a 6G network, then the first network device is a 6G-AMF.

[0396] Step 2: The first network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a first identifier and first information. The first identifier is a temporary identifier used by the terminal device in the first RAT. The first information at least indicates the mobility registration result of the terminal device on the first network.

[0397] Optionally, if the first network is a 5G network, then the first identifier is 5G-GUTI; if the first network is a 6G network, then the first identifier is 6G-GUTI.

[0398] Optionally, since the terminal device is currently connected to the first network, the first information can indicate that the terminal device's registration on the currently connected first network is valid.

[0399] Step 3: The terminal device sends a registration completion message to the first network device.

[0400] Optionally, the registration completion message is used to confirm that the terminal device's registration on the first network device has taken effect, thereby making the first identifier effective.

[0401] Step 4: The terminal device selects the cell corresponding to the second network to access. At this time, the terminal device sends a registration request message to the second network device on the second network. The registration request message carries the first identifier.

[0402] Optionally, the terminal device may include a first identifier in the registration request message sent to the second network device, thereby allowing the second network device to determine that the terminal device has previously registered on the first network device based on the first identifier.

[0403] Optionally, if the second network is a 5G network, then the second network device is a 5G-AMF; if the second network is a 6G network, then the second network device is a 6G-AMF.

[0404] Step 5: The second network device determines the first network device based on the first identifier and sends a context request message to the first network device; wherein the context request message carries a registration request message.

[0405] Step 6: The first network device sends a context response message to the second network device. The context response message may carry the capability information of the first network device.

[0406] Optionally, the capability information here can indicate whether the first network device has or does not have the capability to retain context. The capability information can also be obtained without using context response messages. The second network device can interact with the first network device separately through other signaling to obtain the capability information of the first network device.

[0407] Step 7: The second network device returns a context confirmation message to the first network device, which carries indication information.

[0408] Optionally, after obtaining the capability information of the first network device, the second network device can generate indication information based on the capability information. That is, it can generate indication information to instruct the first network device not to retain the session list if the first network device does not have the capability to retain the context. Alternatively, even if the first network device has the capability to retain the context, the second network device may still decide to maintain the registration validity of the terminal device in the second network. Thus, it can also generate indication information to instruct the first network device not to retain the session list and return the indication information to the first network device in the context confirmation message.

[0409] Step 8: The second network device sends an update request message to the third network device, and the update request message carries a type indication message.

[0410] Optionally, when the second network device sends an update request message to the third network device, since the indication information indicates that the first network device does not retain the session list, the type indication message can be a type indication message indicating that only the second network's second RAT is supported. For example, if the first network is a 5G network and the second network is a 6G network, then the type indication message is 6G only, indicating that the terminal device's access is only valid in 6G.

[0411] Step 9: The third network device sends an update response message to the second network device, and the update response message carries a type confirmation message.

[0412] Optionally, after receiving the update request message sent by the second network device, the third network device may include a type confirmation message indicating that the registration of the first network is unavailable in the update response message. For example, if the first network is a 5G network and the second network is a 6G network, then the type confirmation message may only indicate that 6G-RAN is available.

[0413] Step 10: The second network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a second identifier and first information. The second identifier is a temporary identifier used by the terminal device in the second RAT. The first information indicates at least that the terminal device's registration on the first network is invalid.

[0414] Optionally, if the second network is a 5G network, then the second identifier is 5G-GUTI; if the second network is a 6G network, then the second identifier is 6G-GUTI.

[0415] Optionally, the first information sent by the second network device to the terminal device only indicates that the terminal device's registration on the current second network is valid, that is, it indicates that the terminal device's registration on the first network is invalid.

[0416] Step 11: The terminal device sends a registration completion message to the second network device.

[0417] Optionally, the registration completion message is used to confirm that the terminal device's registration on the second network device has taken effect, thereby making the second identifier effective.

[0418] Step 12: When the terminal device reconnects to the first network while in an idle state, since the first information sent in step 10 indicates that the registration on the first network is invalid, the terminal device needs to send a mobility registration request message on the first network. Only after the registration request is approved can it access the first network.

[0419] Optionally, if the first network is a 5G network and the second network is a 6G network, when the terminal device accesses the 6G network and then the 5G network again, since the first information sent in step 10 indicates that the terminal device's registration on the 5G network is invalid, the terminal device needs to send a mobility registration request message on the 5G network when accessing the 5G network. Only after the registration request is approved can the terminal device access the 5G network.

[0420] Optionally, if the first network is a 6G network and the second network is a 5G network, when the terminal device accesses the 6G network, then the 5G network, and then the 6G network, the terminal device needs to send a mobility registration request message on the 6G network when accessing the 6G network because the first information sent in step 10 indicates that the terminal device's registration on the 6G network is invalid. Only after the registration request is approved can the terminal device access the 6G network.

[0421] Example 3

[0422] In this embodiment, the second network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed. At this time, the core network devices of the first RAT and the core network devices of the second RAT are centrally deployed in the second network device.

[0423] Step 1: The terminal device sends a registration request message to the second network device on the first network.

[0424] Optionally, if the first network is a 5G network and the second network is a 6G network, then the second network device here is 5G+6G-AMF.

[0425] Step 2: The second network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a first identifier and first information. The first identifier is a temporary identifier used by the terminal device in the first RAT. The first information at least indicates the mobility registration result of the terminal device on the first network.

[0426] Optionally, if the first network is a 5G network, then the first identifier is 5G-GUTI; if the first network is a 6G network, then the first identifier is 6G-GUTI.

[0427] Optionally, since the terminal device is currently connected to the first network, the first information can indicate that the terminal device's registration on the currently connected first network is valid.

[0428] Step 3: The terminal device sends a registration completion message to the first network device.

[0429] Optionally, the registration completion message is used to confirm that the terminal device's registration on the first network device has taken effect, thereby making the first identifier effective.

[0430] Step 4: The terminal device selects the cell corresponding to the second network to access. At this time, the terminal device sends a registration request message to the second network device on the second network.

[0431] Optionally, since both the first network and the second network interact with the terminal device through the second network device, the second network device can directly determine that the terminal device has previously registered on the first network.

[0432] Step 5: The second network device sends an update request message to the third network device, and the update request message carries a type indication message.

[0433] Optionally, the type indication message can indicate the type of the currently accessed or recently accessed network. For example, if the first network is a 5G network and the second network is a 6G network, then the type indication message can be 6G-RAN.

[0434] Step 6: The third network device sends an update response message to the second network device.

[0435] Optionally, after receiving the update request message sent by the second network device, the third network device may send an update response message to the second network device to indicate the network change of the terminal device.

[0436] Step 7: The second network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a second identifier and first information. The second identifier is a temporary identifier used by the terminal device in the second RAT. The first information at least indicates that the terminal device's registration on the first network is valid.

[0437] Optionally, since the first network and the second network interact with the terminal device simultaneously through the second network device, the second network device can retain the validity of the terminal device's registration on the first network because the terminal device does not switch network devices when switching networks. Therefore, the first information indicates that the terminal device's registration on both the first network and the second network is valid, and the second identifier is GUTI. There is no need to distinguish between the first network and the second network, and the second identifier can be used on both the first network and the second network simultaneously.

[0438] Step 8: The terminal device sends a registration completion message to the second network device.

[0439] Optionally, the registration completion message is used to confirm that the terminal device's registration on the second network device has taken effect, thereby making the second identifier effective.

[0440] Step 9: When the terminal device is in an idle state and wants to return to the first network from the currently accessed second network, since the first information sent in step 7 indicates that the terminal device's registration in the first network is valid while its registration in the second network is also valid, the terminal device only needs to send a service request message on the first network to directly access the first network using the first RAT.

[0441] Optionally, if the first network is a 5G network and the second network is a 6G network, when the terminal device accesses the 6G network and then the 5G network again, since the first information sent in step 10 indicates that the terminal device's registration on the 5G network is valid while its current registration on the 6G network is also valid, the terminal device only needs to send a service request message when accessing the 5G network to directly access the 5G network.

[0442] Optionally, if the first network is a 6G network and the second network is a 5G network, then when the terminal device accesses the 6G network, then the 5G network, and then the 6G network, since the first information sent in step 10 indicates that the terminal device's registration on the 6G network is valid while its current registration on the 5G network is also valid, the terminal device only needs to send a service request message when accessing the 6G network to directly access the 6G network.

[0443] Example 4

[0444] In this embodiment, both the first network device and the second network device are core network devices of the first RAT and the second RAT respectively, which are centrally deployed. In this case, the core network devices of the first RAT and the second RAT are centrally deployed in the first network device and the second network device.

[0445] Step 1: The terminal device sends a registration request message to the first network device.

[0446] Optionally, if the first network is a 5G network and the second network is a 6G network, then the first network device is 5G+6G-AMF1.

[0447] Step 2: The first network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a first identifier and first information. The first identifier is a temporary identifier used by the terminal device in the first RAT. The first information at least indicates the mobility registration result of the terminal device on the first network.

[0448] Optionally, if the first network is a 5G network, then the first identifier is 5G-GUTI; if the first network is a 6G network, then the first identifier is 6G-GUTI.

[0449] Optionally, since the terminal device is currently connected to the first network, the first information can indicate that the terminal device's registration on the currently connected first network is valid.

[0450] Step 3: The terminal device sends a registration completion message to the first network device.

[0451] Optionally, the registration completion message is used to confirm that the terminal device's registration on the first network device has taken effect, thereby making the first identifier effective.

[0452] Step 4: The terminal device selects the cell corresponding to the second network to access. At this time, the terminal device sends a registration request message to the second network device on the second network. The registration request message carries the first identifier.

[0453] Optionally, the terminal device may include a first identifier in the registration request message sent to the second network device, thereby allowing the second network device to determine that the terminal device has previously registered on the first network device based on the first identifier.

[0454] Optionally, if the first network is a 5G network and the second network is a 6G network, then the second network device is 5G+6G-AMF2.

[0455] Step 5: The second network device determines the first network device based on the first identifier and sends a context request message to the first network device; wherein the context request message carries a registration request message.

[0456] Step 6: The first network device sends a context response message to the second network device.

[0457] Step 7: The second network device sends an update request message to the third network device, and the update request message carries a type indication message.

[0458] Optionally, the type indication message at this time may only be a type indication message indicating that the second RAT supports the second network. For example, if the first network is a 5G network and the second network is a 6G network, then the type indication message is 6G-RAN.

[0459] Step 8: The third network device sends an update response message to the second network device.

[0460] Optionally, the third network device may send an update response message to the second network device to confirm the validity of the 6G-RAN.

[0461] Step 9: The second network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a second identifier and first information. The second identifier is a temporary identifier used by the terminal device in the second RAT. The first information at least indicates that the terminal device's registration on the first network is invalid.

[0462] Optionally, if the second network is a 5G network, then the second identifier is 5G-GUTI; if the second network is a 6G network, then the second identifier is 6G-GUTI.

[0463] Step 10: The terminal device sends a registration completion message to the second network device.

[0464] Optionally, the registration completion message is used to confirm that the terminal device's registration on the second network device has taken effect, thereby making the second identifier effective.

[0465] Step 11: When the terminal device is in an idle state and wants to return to the first network from the currently accessed second network, since the first information sent in step 9 indicates that the terminal device's registration on the first network is invalid, the terminal device needs to send a mobility registration request message on the first network. Only after the registration request is approved can it access the first network.

[0466] Optionally, if the first network is a 5G network and the second network is a 6G network, when the terminal device accesses the 6G network and then the 5G network again, since the first information sent in step 10 indicates that the terminal device's registration on the 5G network is invalid, the terminal device needs to send a mobility registration request message on the 5G network when accessing the 5G network. Only after the registration request is approved can the terminal device access the 5G network.

[0467] Optionally, if the first network is a 6G network and the second network is a 5G network, when the terminal device accesses the 6G network, then the 5G network, and then the 6G network, the terminal device needs to send a mobility registration request message on the 6G network when accessing the 6G network because the first information sent in step 10 indicates that the terminal device's registration on the 6G network is invalid. Only after the registration request is approved can the terminal device access the 6G network.

[0468] Example 5

[0469] In this embodiment, both the first network device and the second network device are core network devices of the first RAT and the second RAT respectively, which are centrally deployed. In this case, the core network devices of the first RAT and the second RAT are centrally deployed in the first network device and the second network device.

[0470] Step 1: The terminal device is currently connected to the first network through the first network device. However, during the movement, the first network reassigns a second network device to the terminal device due to the change in the location of the terminal device. Therefore, the terminal device needs to send a registration request message to the second network device, and the registration request message carries a third identifier.

[0471] Optionally, the first network can be a 5G network or a 6G network, the first network device is 5G+6G-AMF2, and the second network device is 5G+6G-AMF3.

[0472] Optionally, the third identifier is GUTI, without distinguishing between the first network and the second network. The third identifier can be used for both the first network and the second network.

[0473] Step 2: The second network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a third identifier and first information. The third identifier is a temporary identifier used by the terminal device in the first RAT and the second RAT. The first information at least indicates that the terminal device's registration on the first network is valid.

[0474] Step 3: The terminal device sends a registration completion message to the second network device.

[0475] Optionally, the registration completion message is used to confirm that the terminal device's registration on the second network device has taken effect, thereby making the third identifier effective.

[0476] Or there may be the following situations (similar to Example 4):

[0477] Step 1: The terminal device is currently connected to the first network through the first network device, but during the movement, it connects to the second network. The second network selects the second network device to serve the terminal device. At this time, the terminal device needs to send a registration request message to the second network device on the second network. The registration request message carries a third identifier.

[0478] Optionally, the terminal device may carry a third identifier in the registration request message sent to the second network device, thereby allowing the second network device to determine that the terminal device has previously registered on the first network device based on the third identifier.

[0479] Optionally, if the first network is a 5G network and the second network is a 6G network, then the second network device is 5G+6G-AMF2.

[0480] Step 2: The second network device sends an update request message to the third network device, and the update request message carries a type indication message.

[0481] Optionally, the type indication message at this time may only be a type indication message indicating that the second RAT supports the second network. For example, if the first network is a 5G network and the second network is a 6G network, then the type indication message is 6G-RAN.

[0482] Step 3: The third network device sends an update response message to the second network device.

[0483] Optionally, the third network device may send an update response message to the second network device to confirm the validity of the 6G-RAN.

[0484] Step 4: The second network device sends a registration acceptance message to the terminal device. The registration acceptance message carries a second identifier and first information. The second identifier is a temporary identifier used by the terminal device in the second RAT. The first information indicates at least that the terminal device's registration on the first network is invalid.

[0485] Optionally, if the second network is a 5G network, then the second identifier is 5G-GUTI; if the second network is a 6G network, then the second identifier is 6G-GUTI.

[0486] Step 5: The terminal device sends a registration completion message to the second network device.

[0487] Optionally, the registration completion message is used to confirm that the terminal device's registration on the second network device has taken effect, thereby making the second identifier effective.

[0488] Step 6: When the terminal device is in an idle state and wants to return to the first network from the currently accessed second network, since the first information sent in step 9 indicates that the terminal device's registration on the first network is invalid, the terminal device needs to send a mobility registration request message on the first network. Only after the registration request is approved can it access the first network.

[0489] Optionally, if the first network is a 5G network and the second network is a 6G network, when the terminal device accesses the 6G network and then the 5G network again, since the first information sent in step 10 indicates that the terminal device's registration on the 5G network is invalid, the terminal device needs to send a mobility registration request message on the 5G network when accessing the 5G network. Only after the registration request is approved can the terminal device access the 5G network.

[0490] Optionally, if the first network is a 6G network and the second network is a 5G network, when the terminal device accesses the 6G network, then the 5G network, and then the 6G network, the terminal device needs to send a mobility registration request message on the 6G network when accessing the 6G network because the first information sent in step 10 indicates that the terminal device's registration on the 6G network is invalid. Only after the registration request is approved can the terminal device access the 6G network.

[0491] Based on the above embodiments, in order to facilitate understanding of the communication method provided in this application, the following describes possible implementation schemes of the communication method applicable to the embodiments of this application based on the interaction process between the UE (terminal device) and the first network device, the second network device and the third network device.

[0492] Referring to Figure 16, in some embodiments, the first network is a 5G network, the first network device is a 5G-AMF, the second network is a 6G network, the second network device is a 6G-AMF, and the third network device is a 5G+6G-SMF. The specific steps are as follows:

[0493] S1600, UE sends a registration request message to 5G-AMF.

[0494] Optionally, the registration request message may include the UE identification number (ID), which may be SUCI or 5G-GUTI, the registration type (initial registration or mobility update registration), and the UE security capabilities.

[0495] After receiving the registration request message, S1601 and 5G-AMF trigger the authentication process.

[0496] Optionally, the authentication process is called the Authentication process.

[0497] S1602 and 5G-AMF send a security mode command message to the UE.

[0498] Optionally, the Security Mode Command message is a Security Mode Command message. The Security Mode Command message carries the index information of the security key, also known as the Key Set Identifier (KSI), UE security capabilities, integrity algorithm, ciphering algorithm, and a complete Initial NAS message request indication.

[0499] S1603, the UE returns a safe mode completion message to the 5G-AMF.

[0500] Optionally, the Security Mode Complete message is a Security Mode Complete message. The Security Mode Complete message carries a complete registration request message. In addition to the content in S1600, the complete registration request here may also include the requested slice information, UE capability information, etc. Among them, the UE capability information may include that the UE has 6G capability.

[0501] S1604, 5G-AMF sends a registration acceptance message to the UE.

[0502] Optionally, the registration acceptance message may carry a first identifier, namely 5G-GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result, the value of which can be set to 5G only (if the UE has not registered in 6G); this 5G only registration result is used to indicate that it is only valid for the current 5G access.

[0503] S1605, the UE returns a registration completion message to the 5G-AMF to confirm that the 5G-GUTI is effective.

[0504] S1606. The UE initiates the establishment of a PDU session in the 5G system according to service needs.

[0505] S1607, the UE selects to access the 6G cell and sends a registration request message to the 6G-AMF through the 6G-RAN.

[0506] Optionally, the registration request message may carry information such as registration type, 5G-GUTI, UE capability information, and requested network slice (Requested NSSAI). The registration type can be mobility management registration or mobility registration for 5G to 6G switchover.

[0507] S1608, 6G-AMF selects 5G-AMF according to 5G-GUTI and sends a context request message to 5G-AMF; wherein, the context request message carries the registration request message in S1607.

[0508] Optionally, the context request message is the Namf_Communication_UEContext Transfer Request message.

[0509] S1609, 5G-AMF returns a context response message to 6G-AMF.

[0510] Optionally, the context response message is the Namf_Communication_UEContext Transfer Response message. The Namf_Communication_UEContext Transfer Response message can carry the UE context, including security context, PDU session information (PDU session ID), single network slice selection assistance, SMF information corresponding to each PDU session control, Allowed NSSAI, and UE capability information.

[0511] S1610 and 6G-AMF acquire 5G-AMF capability information.

[0512] Optionally, the 5G-AMF capability information refers to whether the 5G-AMF has the ability to retain context. The 6G-AMF can obtain the 5G-AMF capability information from the Network Repository Function (NRF) before S1608 or carry it in the S1609 message.

[0513] S1611, 6G-AMF returns a context confirmation message to 5G-AMF.

[0514] Optionally, the context confirmation message is a Namf_Communication_UEContext Transfer Ack message. If the 5G-AMF has the capability to retain context, the Namf_Communication_UEContext Transfer Ack message sent by the 6G-AMF to the 5G-AMF carries a 5G context retention indication. This indication signifies that the UE is in a normal registration state on both 5G and 6G. Furthermore, a list of retained PDU sessions can be specified. This list is a collection of multiple PDU session IDs. For PDU sessions not in the list, the 5G-AMF can choose to release them or mark them as unavailable.

[0515] S1612 and 6G-AMF send update request messages to 5G+6G-SMF.

[0516] Optionally, the update request message is the Nsmf_PDUSession_UpdateSMContext Request message, which carries a type indication message (RAT type). The RAT type is either 5G+6G or 6G-RAN, but it also indicates that the 5G+6G-SMF retains the 5G-RAN RAT type as available.

[0517] S1613, 5G+6G-SMF sends an update response message to 6G-AMF.

[0518] Optionally, the update response message is the Nsmf_PDUSession_UpdateSMContext Response message, which carries a type confirmation message to confirm that it is available for both 5G-RAN and 6G-RAN.

[0519] S1614 and 6G-AMF send a registration acceptance message to the UE.

[0520] Optionally, the registration acceptance message may carry a second identifier, namely 6G-GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result. The value of the registration result can be set to 5G+6G. The 5G+6G registration result is used to indicate that the UE's current 6G-RAN access is valid, and its 5G-RAN access is also valid.

[0521] S1615, the UE sends a registration completion message to the 6G-AMF.

[0522] Optionally, the registration completion message is used to confirm that 6G-GUTI is effective.

[0523] S1616 When a UE is in an idle state and is accessing a 5G network from the currently accessed 6G network, it only needs to send a service request message on the 5G network to directly access the 5G network.

[0524] Optionally, the service request message is a Service request. When the UE is in idle state, if S1614 returns a 5G+6G Registration result, then when the UE moves between the current 5G registration area and the 6G registration area, or when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the UE only needs to send a Service request. If S1614 returns a 5G only or 6G only Registration result, then when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the message sent by the UE is a Mobility Update Registration Request message or a Registration Request message (registration type: Mobility Update).

[0525] Referring to Figure 17, in some embodiments, the first network is a 5G network, the first network device is a 5G-AMF, the second network is a 6G network, the second network device is a 6G-AMF, and the third network device is a 5G+6G-SMF. The specific steps are as follows:

[0526] S1700, UE sends a registration request message to 5G-AMF.

[0527] Optionally, the registration request message may include the UE identification number (ID), which may be SUCI or 5G-GUTI, the registration type (initial registration or mobility update registration), and the UE security capabilities.

[0528] After receiving the registration request message, S1701 and 5G-AMF trigger the authentication process.

[0529] Optionally, the authentication process is called the Authentication process.

[0530] S1702 and 5G-AMF send a security mode command message to the UE.

[0531] Optionally, the Security Mode Command message is a Security Mode Command message. The Security Mode Command message carries the index information of the security key, also known as the Key Set Identifier (KSI), UE security capabilities, integrity algorithm, ciphering algorithm, and a complete Initial NAS message request indication.

[0532] S1703, the UE returns a safe mode completion message to the 5G-AMF.

[0533] Optionally, the Security Mode Complete message is a Security Mode Complete message. The Security Mode Complete message carries a complete registration request message. In addition to the content in S1700, the complete registration request here may also include the requested slice information, UE capability information, etc. Among them, the UE capability information may include that the UE has 6G capability.

[0534] S1704, 5G-AMF sends a registration acceptance message to the UE.

[0535] Optionally, the registration acceptance message may carry a first identifier, namely 5G-GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result, the value of which can be set to 5G only (if the UE has not registered in 6G); this 5G only registration result is used to indicate that it is only valid for the current 5G access.

[0536] S1705, the UE returns a registration completion message to the 5G-AMF to confirm that the 5G-GUTI is effective.

[0537] S1706. The UE initiates the establishment of a PDU session in the 5G system according to service needs.

[0538] S1707, the UE selects to access the 6G cell and sends a registration request message to the 6G-AMF through the 6G-RAN.

[0539] Optionally, the registration request message may carry information such as registration type, 5G-GUTI, UE capability information, and requested network slice (Requested NSSAI). The registration type can be mobility management registration or mobility registration for 5G to 6G switchover.

[0540] S1708, 6G-AMF selects 5G-AMF according to 5G-GUTI and sends a context request message to 5G-AMF; wherein, the context request message carries the registration request message in S1707.

[0541] Optionally, the context request message is the Namf_Communication_UEContext Transfer Request message.

[0542] S1709, 5G-AMF returns a context response message to 6G-AMF.

[0543] Optionally, the context response message is the Namf_Communication_UEContext Transfer Response message. The Namf_Communication_UEContext Transfer Response message can carry the UE context, including security context, PDU session information (PDU session ID), single network slice selection assistance, SMF information corresponding to each PDU session control, Allowed NSSAI, and UE capability information.

[0544] S1710 and 6G-AMF acquire 5G-AMF capability information.

[0545] Optionally, the 5G-AMF capability information refers to whether the 5G-AMF has the capability to retain context. The 6G-AMF can obtain the 5G-AMF capability information from the Network Repository Function (NRF) before S1708 or carry it in the S1709 message.

[0546] S1711, 6G-AMF returns a context confirmation message to 5G-AMF.

[0547] Optionally, the context confirmation message is the Namf_Communication_UEContext Transfer Ack message. If the 5G-AMF does not have the ability to retain the context, or if the 5G-AMF has the ability to retain the context but the 6G-AMF decides to maintain the 6G-RAN registration as valid only, then the Namf_Communication_UEContext Transfer Ack message sent by the 6G-AMF to the 5G-AMF carries a 5G context not retained indication. Carrying the 5G context not retained indication is used to indicate that the UE is only in a normal registration state in 6G.

[0548] S1712 and 6G-AMF send update request messages to 5G+6G-SMF.

[0549] Optionally, the update request message is the Nsmf_PDUSession_UpdateSMContext Request message, which carries a type indication message (RAT type) with the RAT type being 6G-RAN.

[0550] S1713, 5G+6G-SMF sends an update response message to 6G-AMF.

[0551] Optionally, the update response message is an Nsmf_PDUSession_UpdateSMContext Response message, which carries a type confirmation message to confirm 6G-RAN availability.

[0552] S1714 and 6G-AMF send a registration acceptance message to the UE.

[0553] Optionally, the registration acceptance message may carry a second identifier, namely 6G-GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result. The value of the registration result can be set to 6G only. The 6G only registration result is used to indicate that the UE is only valid for access in the current 6G-RAN.

[0554] S1715, the UE sends a registration completion message to the 6G-AMF.

[0555] Optionally, the registration completion message is used to confirm that 6G-GUTI is effective.

[0556] S1716. When a UE is in an idle state and accesses a 5G network from the currently accessed 6G network, it needs to send a mobility update registration request message or a registration request message (registration type: mobility update) on the 5G network.

[0557] Optionally, when the UE is in idle state, if S1714 returns a 5G+6G Registration result, then when the UE moves between the current 5G registration area and the 6G registration area, or when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the UE only needs to send a Service request; if S1714 returns a 5G only or 6G only Registration result, then when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the message sent by the UE is a mobility update registration request message or a registration request message (registration type: mobility update).

[0558] Referring to Figure 18, in some embodiments, the first network is a 5G network, the second network is a 6G network, the first and second networks share a 5G+6G-AMF, and the third network device is a 5G+6G-SMF. The specific steps are as follows:

[0559] S1800, UE sends a registration request message to 5G+6G-AMF.

[0560] Optionally, the registration request message may include the UE identification number (ID), which may be SUCI or 5G-GUTI, the registration type (initial registration or mobility update registration), and the UE security capabilities.

[0561] After receiving the registration request message, S1801 and 5G+6G-AMF trigger the authentication process.

[0562] Optionally, the authentication process is called the Authentication process.

[0563] S1802 and 5G+6G-AMF send a security mode command message to the UE.

[0564] Optionally, the Security Mode Command message is a Security Mode Command message. The Security Mode Command message carries the index information of the security key, also known as the Key Set Identifier (KSI), UE security capabilities, integrity algorithm, ciphering algorithm, and a complete Initial NAS message request indication.

[0565] S1803, the UE returns a safe mode completion message to the 5G+6G-AMF.

[0566] Optionally, the Security Mode Complete message is a Security Mode Complete message. The Security Mode Complete message carries a complete registration request message. In addition to the content in S1800, the complete registration request here may also include the requested slice information, UE capability information, etc. Among them, the UE capability information may include that the UE has 6G capability.

[0567] S1804 and 5G+6G-AMF send a registration acceptance message to the UE.

[0568] Optionally, the registration acceptance message may carry a first identifier, namely 5G-GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result, the value of which can be set to 5G only (if the UE has not registered in 6G); this 5G only registration result is used to indicate that it is only valid for the current 5G access.

[0569] S1805, the UE returns a registration completion message to the 5G+6G-AMF to confirm that the 5G-GUTI is effective.

[0570] S1806. The UE initiates the establishment of a PDU session in the 5G system according to service needs.

[0571] S1807, the UE selects to access the 6G cell and sends a registration request message to the 5G+6G-AMF through the 6G-RAN.

[0572] Optionally, the registration request message may carry information such as registration type, 5G-GUTI, UE capability information, and requested network slice (Requested NSSAI). The registration type can be mobility management registration or mobility registration for 5G to 6G switchover.

[0573] S1808 and 5G+6G-AMF send an update request message to 5G+6G-SMF.

[0574] Optionally, the update request message is an Nsmf_PDUSession_UpdateSMContext Request message, which carries a type indication message (RAT type). The RAT type is 6G-RAN, and this RAT type is used to indicate the most recent access RAT type.

[0575] S1809, 5G+6G-SMF sends an update response message to 5G+6G-AMF.

[0576] Optionally, the update response message is an Nsmf_PDUSession_UpdateSMContext Response message, which carries a type confirmation message to confirm 6G-RAN availability.

[0577] S1810 and 5G+6G-AMF send a registration acceptance message to the UE.

[0578] Optionally, the registration acceptance message may carry a second identifier, namely GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result. The value of the registration result can be set to 5G+6G. This 5G+6G registration result is used to indicate that the UE's access is valid in both 6G-RAN and 5G-RAN. Furthermore, the GUTI is used to be effective simultaneously in 5G and 6G. That is, the UE uses the GUTI or the temporary user equipment identifier (SAE Temporary Mobile Station Identifier, S-TMSI) in the GUTI as the paging ID when in the idle state of 5G and 6G.

[0579] S1811, the UE sends a registration completion message to the 5G+6G-AMF.

[0580] Optionally, the registration completion message is used to confirm that the GUTI is effective.

[0581] S1812. When the UE is in an idle state and accesses the 5G network from the currently accessed 6G network, it only needs to send a service request message on the 5G network to directly access the 5G network.

[0582] Optionally, the service request message is a Service request. When the UE is in idle state, if S1810 returns a 5G+6G Registration result, then when the UE moves between the current 5G registration area and the 6G registration area, or when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the UE only needs to send a Service request. If S1810 returns a 5G only or 6G only Registration result, then when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the message sent by the UE is a Mobility Update Registration Request message or a Registration Request message (registration type: Mobility Update).

[0583] Referring to Figure 19, in some embodiments, the first network is a 5G network, the second network is a 6G network, the first network device is 5G+6G-AMF1, the second network device is 5G+6G-AMF2, and the third network device is 5G+6G-SMF. The specific steps are as follows:

[0584] S1900, UE sends a registration request message to 5G+6G-AMF1.

[0585] Optionally, the registration request message may include the UE identification number (ID), which may be SUCI or 5G-GUTI, the registration type (initial registration or mobility update registration), and the UE security capabilities.

[0586] After receiving the registration request message, S1901 and 5G+6G-AMF1 trigger the authentication process.

[0587] Optionally, the authentication process is called the Authentication process.

[0588] S1902 and 5G+6G-AMF1 send a security mode command message to the UE.

[0589] Optionally, the Security Mode Command message is a Security Mode Command message. The Security Mode Command message carries the index information of the security key, also known as the Key Set Identifier (KSI), UE security capabilities, integrity algorithm, ciphering algorithm, and a complete Initial NAS message request indication.

[0590] S1903, the UE returns a safe mode completion message to 5G+6G-AMF1.

[0591] Optionally, the Security Mode Complete message is a Security Mode Complete message. The Security Mode Complete message carries a complete registration request message. In addition to the content in S1900, the complete registration request here may also include the requested slice information, UE capability information, etc. Among them, the UE capability information may include that the UE has 6G capability.

[0592] S1904 and 5G+6G-AMF1 send a registration acceptance message to the UE.

[0593] Optionally, the registration acceptance message may carry a first identifier, namely 5G-GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result, the value of which can be set to 5G only (if the UE has not registered in 6G); this 5G only registration result is used to indicate that it is only valid for the current 5G access.

[0594] S1905, the UE returns a registration completion message to 5G+6G-AMF1 to confirm that 5G-GUTI is effective.

[0595] S1906. The UE initiates the establishment of a PDU session in the 5G system according to service needs.

[0596] S1907, the UE selects to access the 6G cell and sends a registration request message to 5G+6G-AMF2 through 6G-RAN.

[0597] Optionally, the registration request message may carry information such as registration type, 5G-GUTI, UE capability information, and requested network slice (Requested NSSAI). The registration type can be mobility management registration or mobility registration for 5G to 6G switchover.

[0598] S1908, 5G+6G-AMF2 selects 5G+6G-AMF1 according to 5G-GUTI and sends a context request message to 5G+6G-AMF1; wherein, the context request message carries the registration request message in S1907.

[0599] Optionally, the context request message is the Namf_Communication_UEContext Transfer Request message.

[0600] S1909, 5G+6G-AMF1 returns a context response message to 5G+6G-AMF2.

[0601] Optionally, the context response message is the Namf_Communication_UEContext Transfer Response message. The Namf_Communication_UEContext Transfer Response message can carry the UE context, including security context, PDU session information (PDU session ID), single network slice selection assistance, SMF information corresponding to each PDU session control, Allowed NSSAI, and UE capability information.

[0602] S1910 and 5G+6G-AMF2 send an update request message to 5G+6G-SMF.

[0603] Optionally, the update request message is the Nsmf_PDUSession_UpdateSMContext Request message, which carries a type indication message (RAT type) with the RAT type being 6G-RAN.

[0604] S1911 and 5G+6G-SMF send an update response message to 5G+6G-AMF2.

[0605] Optionally, the update response message is an Nsmf_PDUSession_UpdateSMContext Response message, which carries a type confirmation message to confirm 6G-RAN availability.

[0606] S1912 and 5G+6G-AMF2 send a registration acceptance message to the UE.

[0607] Optionally, the registration acceptance message may carry a second identifier, namely 6G-GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result. The value of the registration result can be set to 6G only. The 6G only registration result is used to indicate that the UE is only valid for access in the current 6G-RAN.

[0608] S1913, UE sends a registration completion message to 5G+6G-AMF2.

[0609] Optionally, the registration completion message is used to confirm that 6G-GUTI is effective.

[0610] S1914. When a terminal device is in an idle state and accesses a 5G network from the currently accessed 6G network, it needs to send a mobility update registration request message or a registration request message (registration type: mobility update) on the 5G network.

[0611] Optionally, the service request message is a Service request. When the UE is in idle state, if S1912 returns a 5G+6G Registration result, then when the UE moves between the current 5G registration area and the 6G registration area, or when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the UE only needs to send a Service request. If S1912 returns a 5G only or 6G only Registration result, then when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the message sent by the UE is a Mobility Update Registration Request message or a Registration Request message (registration type: Mobility Update).

[0612] Referring to Figure 20, in some embodiments, the first network is a 5G network, the second network is a 6G network, the first network device is 5G+6G-AMF2, the second network device is 5G+6G-AMF3, and the third network device is 5G+6G-SMF. The specific steps are as follows:

[0613] S2000: When the UE moves out of its original registration area, the 6G-RAN selects 5G+6G-AMF3 to serve the UE, and the UE sends a registration request message to 5G+6G-AMF3 through the 6G-RAN.

[0614] Optionally, the registration request message may include the UE identification number (ID), which may be SUCI or 5G-GUTI, the registration type (initial registration or mobility update registration), and the UE security capabilities.

[0615] S2001 and 5G+6G-AMF3 send a registration acceptance message to the UE.

[0616] Optionally, the registration acceptance message may carry a third identifier, namely 6G-GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result, the value of which can be set to 6G only. This 6G only registration result is used to indicate that it is only valid for the current 6G-RAN access.

[0617] S2002, the UE returns a registration completion message to 5G+6G-AMF3 to confirm that 6G-GUTI is effective.

[0618] or,

[0619] S2003. The UE moves from 5G-RAN to 6G-RAN. 6G-RAN selects 5G+6G-AMF3 to serve the UE. The UE sends a registration request message to 5G+6G-AMF3 through 6G-RAN.

[0620] Optionally, the registration request message may carry information such as registration type, 5G-GUTI, UE capability information, and requested network slice (Requested NSSAI). The registration type can be mobility management registration or mobility registration for 5G to 6G switchover.

[0621] S2004, 5G+6G-AMF3 sends an update request message to 5G+6G-SMF.

[0622] Optionally, the update request message is the Nsmf_PDUSession_UpdateSMContext Request message, which carries a type indication message (RAT type) with the RAT type being 6G-RAN.

[0623] S2005 and 5G+6G-SMF send an update response message to 5G+6G-AMF3.

[0624] Optionally, the update response message is the Nsmf_PDUSession_UpdateSMContext Response message, which carries a type confirmation message to confirm that it is available for both 5G-RAN and 6G-RAN.

[0625] S2006 and 5G+6G-AMF3 send a registration acceptance message to the UE.

[0626] Optionally, the registration acceptance message may carry a second identifier, namely 6G-GUTI, and the registration area, as well as information such as the available network slice (Allowed NSSAI). The registration acceptance message may also carry the first information, namely the registration result. The value of the registration result can be set to 6G only. The 6G only registration result is used to indicate that the UE is only valid for the current 6G-RAN access.

[0627] S2007, UE sends a registration completion message to 5G+6G-AMF3.

[0628] Optionally, the registration completion message is used to confirm that 6G-GUTI is effective.

[0629] S2008. When a terminal device is in an idle state and accesses a 5G network from the currently accessed 6G network, it needs to send a mobility update registration request message or a registration request message (registration type: mobility update) on the 5G network.

[0630] Optionally, the service request message is a Service request. When the UE is in idle state, if S2006 returns a 5G+6G Registration result, then when the UE moves between the current 5G registration area and the 6G registration area, or when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the UE only needs to send a Service request. If S2006 returns a 5G only or 6G only Registration result, then when the cell accessed by the UE changes from 5G to 6G, or from 6G to 5G, the message sent by the UE is a Mobility Update Registration Request message or a Registration Request message (registration type: Mobility Update).

[0631] The preferred embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solutions of this application, and these simple modifications all fall within the protection scope of this application. For example, the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this application will not describe the various possible combinations separately. Furthermore, various different embodiments of this application can also be arbitrarily combined, as long as they do not violate the spirit of this application, they should also be considered as the content disclosed in this application. Moreover, without conflict, the various embodiments and / or the technical features in the various embodiments described in this application can be arbitrarily combined with the prior art, and the resulting technical solutions should also fall within the protection scope of this application.

[0632] It should also be understood that in the various method embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. Furthermore, in the embodiments of this application, the terms "downlink," "uplink," and "sidelink" are used to indicate the transmission direction of signals or data. "Downlink" indicates that the transmission direction of signals or data is a first direction from the site to the user equipment in the cell; "uplink" indicates that the transmission direction of signals or data is a second direction from the user equipment in the cell to the site; and "sidelink" indicates that the transmission direction of signals or data is a third direction from user equipment 1 to user equipment 2. For example, "downlink signal" indicates that the transmission direction of the signal is the first direction. Additionally, in the embodiments of this application, the term "and / or" is merely a description of the association relationship between related objects, indicating that three relationships can exist. Specifically, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0633] Figure 21 is a schematic diagram of the structure of a communication device 2100 provided in an embodiment of this application, which is applied to a terminal device. As shown in Figure 21, the communication device 2100 includes:

[0634] The first receiving unit 2101 is configured to receive first information;

[0635] The first sending unit 2102 is configured to send a service request message or a mobility registration request message on the first network according to the first information when the terminal device accesses the first network.

[0636] In some embodiments, the first sending unit 2102 is further configured to send a service request message on the first network when accessing the first network; wherein the first information indicates that the terminal device's registration on the first network is valid; the service request message is used for the terminal device to access the first network; and the first network adopts a first RAT.

[0637] In some embodiments, the first sending unit 2102 is further configured to send a mobility registration request message on the first network when accessing the first network; wherein the first information indicates that the registration of the terminal device on the first network is invalid; and the first network adopts a first RAT.

[0638] In some implementations, the first receiving unit 2101 is configured to receive first information sent by the first network device; wherein the first network device at least supports the ability to retain context when the terminal accesses the second network; wherein the second network adopts a second RAT.

[0639] In some implementations, the first receiving unit 2101 is configured to receive first information sent by the second network device.

[0640] In some embodiments, the first receiving unit 2101 is further configured to receive a first identifier sent by the first network device; wherein the first identifier is carried in the registration acceptance message sent by the first network device to the terminal device, and the first identifier is a temporary identifier associated with the terminal device and the first RAT.

[0641] In some implementations, the first sending unit 2102 is further configured to send a first identifier to the second network device; wherein the first identifier is carried in a registration request message sent by the terminal device to the second network device; the first identifier is a temporary identifier associated with the terminal device and the first RAT.

[0642] In some embodiments, the first receiving unit 2101 is further configured to receive a second identifier sent by the second network device; wherein the second identifier is carried in the registration acceptance message sent by the second network device to the terminal device, and the second identifier is a temporary identifier associated with the terminal device and the second RAT.

[0643] In some embodiments, the first receiving unit 2101 is further configured to receive a third identifier sent by the second network device; wherein the third identifier is carried in the registration acceptance message sent by the second network device received by the terminal device, and the third identifier is a temporary identifier associated with the terminal device and the first RAT and the second RAT.

[0644] Figure 22 is a schematic diagram of the structure of a communication device 2200 provided in an embodiment of this application, applied to a first network device. As shown in Figure 22, the communication device 2200 includes:

[0645] The second sending unit 2201 is configured to send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used by the terminal device to send a service request message or a mobility registration request message.

[0646] The second sending unit 2201 is configured to send a first identifier to the terminal device; wherein the first identifier is carried in the registration acceptance message sent by the first network device to the terminal device, and the first identifier is a temporary identifier associated with the terminal device and the first RAT.

[0647] In some embodiments, the communication device 2200 further includes: a second receiving unit 2202; the second receiving unit 2202 is configured to receive a context request message sent by a second network device; wherein the context request message carries a registration request message sent by a terminal device to the second network device.

[0648] In some implementations, the second sending unit 2201 is further configured to send capability information to the second network device; wherein the capability information indicates the first network device's ability to retain context; the capability information is carried in a context response message sent by the first network device to the second network device.

[0649] In some embodiments, the second receiving unit 2202 is further configured to receive indication information sent by the second network device; wherein the indication information is used for the first network device to determine whether to retain the session list; the indication information is carried in the context confirmation message sent by the second network device to the first network device.

[0650] Figure 23 is a schematic diagram of the structure of a communication device 2300 provided in an embodiment of this application, applied to a second network device. As shown in Figure 23, the communication device 2300 includes:

[0651] The third sending unit 2301 is configured to send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used for the terminal device to send a service request message or a mobility registration request message.

[0652] In some embodiments, the communication device 2300 further includes: a third receiving unit 2302; the third receiving unit 2302 is configured to receive a first identifier sent by a terminal device; wherein the first identifier is carried in a registration request message sent by the terminal device to the second network device, and the first identifier is a temporary identifier associated with the terminal device and the first RAT.

[0653] In some embodiments, the communication device 2300 further includes: a first determining unit 2303; the first determining unit 2303 is configured to determine a first network device based on a first identifier.

[0654] In some embodiments, the third sending unit 2301 is further configured to send a context request message to the first network device; wherein the context request message carries a registration request message sent by the second network device to the terminal device.

[0655] In some embodiments, the third receiving unit 2302 is further configured to receive capability information sent by the first network device; wherein the capability information indicates the first network device's ability to retain context; the capability information is carried in a context response message sent by the first network device to the second network device.

[0656] In some embodiments, the communication device 2300 further includes: a first acquisition unit 2304; the first acquisition unit 2304 is configured to acquire capability information; wherein the capability information indicates the capability of the first network device to retain context.

[0657] In some embodiments, the third sending unit 2301 is further configured to send indication information to the first network device; wherein the indication information is used for the first network device to determine whether to retain the session list; the indication information is carried in a context confirmation message sent by the second network device to the first network device.

[0658] In some implementations, the first determining unit 2303 is further configured to determine, based on capability information, that the first network device does not have the capability to retain context; and to determine indication information for the first network device to determine not to retain the session list.

[0659] In some implementations, the first determining unit 2303 is further configured to determine, based on capability information, that the first network device has the capability to retain context; determine indication information for the first network device to determine not to retain the session list; or, determine indication information for the first network device to determine to retain the session list.

[0660] In some embodiments, the third sending unit 2301 is further configured to send a type indication message to a third network device; wherein the type indication message is used to indicate the supported RAT type; the type indication message is carried in an update request message sent by the second network device to the third network device.

[0661] In some embodiments, the third receiving unit 2302 is further configured to receive a type confirmation message sent by a third network device; wherein the type confirmation message is used to indicate whether the registration of the first network is available; the type confirmation message is carried in an update response message sent by the third network device to the second network device.

[0662] In some implementations, the third sending unit 2301 is further configured to send a second identifier to the terminal device; wherein the second identifier is carried in a registration acceptance message sent by the second network device to the terminal device, and the second identifier is a temporary identifier associated with the terminal device and the second RAT.

[0663] In some embodiments, the third sending unit 2301 is further configured to send a third identifier to the terminal device; wherein the third identifier is carried in the registration acceptance message sent by the second network device to the terminal device, and the third identifier is a temporary identifier associated with the terminal device and the first RAT and the second RAT.

[0664] Figure 24 is a schematic diagram of the structure of a communication device 2400 provided in an embodiment of this application, applied to a third network device. As shown in Figure 24, the communication device 2400 includes:

[0665] The fourth sending unit 2401 is configured to send a type confirmation message to the second network device; wherein the type confirmation message is used to indicate whether the first network is available.

[0666] In some embodiments, the communication device 2400 further includes: a fourth receiving unit 2402; a third receiving unit 2402 configured to receive type indication information sent by a second network device; wherein the type indication message is used to indicate the supported RAT type; the type indication message is carried in an update request message sent by the second network device received by the third network device.

[0667] Figure 25 is a schematic structural diagram of a communication device provided in an embodiment of this application. This communication device can be a terminal device, or a first network device, a second network device, or a third network device. The communication device 2500 shown in Figure 25 includes a processor 2501, which can call and run computer programs from memory to implement the methods in the embodiments of this application.

[0668] Optionally, as shown in FIG25, the communication device 2500 may further include a memory 2502. The processor 2501 can retrieve and run computer programs from the memory 2502 to implement the methods in the embodiments of this application.

[0669] The memory 2502 can be a separate device independent of the processor 2501, or it can be integrated into the processor 2501.

[0670] Optionally, as shown in FIG25, the communication device 2500 may further include a transceiver 2503, and the processor 2501 may control the transceiver 2503 to communicate with other devices. Specifically, it may send information or data to other devices or receive information or data sent by other devices.

[0671] The transceiver 2503 may include a transmitter and a receiver. The transceiver 2503 may further include an antenna, which may be one or more.

[0672] Optionally, the communication device 2500 may specifically be a terminal device in the embodiments of this application, and the communication device 2500 may implement the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0673] Optionally, the communication device 2500 may specifically be the first network device in the embodiments of this application, and the communication device 2500 may implement the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0674] Optionally, the communication device 2500 may specifically be the second network device in the embodiments of this application, and the communication device 2500 may implement the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0675] Optionally, the communication device 2500 may specifically be a third network device in the embodiments of this application, and the communication device 2500 may implement the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0676] Figure 26 is a schematic structural diagram of a chip provided in an embodiment of this application. The chip 2600 shown in Figure 26 includes a processor 2601, which can call and run computer programs from memory to implement the methods in the embodiments of this application.

[0677] Optionally, as shown in FIG26, chip 2600 may further include memory 2602. Processor 2601 can call and run computer programs from memory 2602 to implement the methods in the embodiments of this application.

[0678] The memory 2602 can be a separate device independent of the processor 2601, or it can be integrated into the processor 2601.

[0679] Optionally, the chip 2600 may also include an input interface 2603. The processor 2601 can control the input interface 2603 to communicate with other devices or chips; specifically, it can acquire information or data sent by other devices or chips.

[0680] Optionally, the chip 2600 may also include an output interface 2604. The processor 2601 can control the output interface 2604 to communicate with other devices or chips, specifically, to output information or data to other devices or chips.

[0681] Optionally, the chip can be applied to the network device in the embodiments of this application, and the chip can implement the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0682] Optionally, the chip can be applied to the terminal device in the embodiments of this application, and the chip can implement the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0683] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0684] This application also provides a computer storage medium storing one or more programs, which can be executed by one or more processors to implement the methods in this application.

[0685] Figure 27 is a schematic block diagram of a first communication system provided in an embodiment of this application. As shown in Figure 27, the communication system 2700 includes a second network device 2701 and a third network device 2702.

[0686] Figure 28 is a schematic block diagram of a second communication system provided in an embodiment of this application. As shown in Figure 28, the communication system 2800 includes a terminal device 2801 and a second network device 2802.

[0687] It should be understood that the processor in the embodiments of this application may be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above method embodiments can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor described above can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0688] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDR SDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0689] It should be understood that the above-described memory is exemplary and not a limiting description. For example, the memory in the embodiments of this application may also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DR RAM), etc. That is to say, the memory in the embodiments of this application is intended to include, but is not limited to, these and any other suitable types of memory.

[0690] This application also provides a computer-readable storage medium for storing computer programs.

[0691] Optionally, the computer-readable storage medium can be applied to the network device in the embodiments of this application, and the computer program causes the computer to execute the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0692] Optionally, the computer-readable storage medium can be applied to the terminal device in the embodiments of this application, and the computer program causes the computer to execute the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0693] This application also provides a computer program product, including computer program instructions.

[0694] Optionally, the computer program product can be applied to the network device in the embodiments of this application, and the computer program instructions cause the computer to execute the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, they will not be described in detail here.

[0695] Optionally, the computer program product can be applied to the terminal device in the embodiments of this application, and the computer program instructions cause the computer to execute the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application. For the sake of brevity, they will not be described in detail here.

[0696] This application also provides a computer program.

[0697] Optionally, the computer program can be applied to the network device in the embodiments of this application. When the computer program is run on the computer, it causes the computer to execute the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0698] Optionally, the computer program can be applied to the terminal device in the embodiments of this application. When the computer program is run on the computer, it causes the computer to execute the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0699] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0700] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0701] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0702] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0703] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0704] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0705] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method applied to a terminal device, the method comprising: The terminal device receives the first information; When connected to the first network, a service request message or a mobility registration request message is sent on the first network based on the first information.

2. The method according to claim 1, wherein, The first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network includes one of the following: The registration of the terminal device on the first network is valid; The registration of the terminal device on the first network is invalid.

3. The method according to claim 2, wherein, The terminal device's registration on the first network is valid, and its registration on the second network is also valid; or, The terminal device's registration on the first network is valid, but its registration on the second network is invalid; or, The terminal device's registration on the first network is invalid, but its registration on the second network is valid; The second network uses a different wireless access technology (RAT) than the first network.

4. The method according to claim 3, wherein, The method further includes: When accessing the first network, a service request message is sent on the first network; wherein, the first information indicates that the terminal device's registration on the first network is valid; the service request message is used for the terminal device to access the first network; the first network uses a first RAT.

5. The method according to claim 3, wherein, The method further includes: When connected to the first network, a mobility registration request message is sent on the first network; wherein the first information indicates that the registration of the terminal device on the first network is invalid; the first network uses a first RAT.

6. The method according to any one of claims 2 to 5, wherein, The method further includes at least one of the following: The system receives the first information sent by the first network device; wherein the first network device at least supports the terminal accessing the second network, and the first network device has the ability to retain context; wherein the second network adopts a second RAT. Receive the first information sent by the second network device.

7. The method according to claim 6, wherein, The first information is carried in the registration acceptance message sent by the first network device received by the terminal device.

8. The method according to claim 7, wherein, The method further includes: The terminal device receives a first identifier sent by the first network device; wherein the first identifier is carried in the registration acceptance message sent by the first network device when the terminal device receives the first identifier, and the first identifier is a temporary identifier associated with the terminal device and the first RAT.

9. The method according to claim 6, wherein, The first information is carried in the registration acceptance message sent by the second network device received by the terminal device.

10. The method according to any one of claims 6 to 8, wherein, The method further includes: Send a first identifier to the second network device; wherein the first identifier is carried in the registration request message sent by the terminal device to the second network device; the first identifier is a temporary identifier associated with the terminal device and the first RAT.

11. The method according to claim 8, wherein, The method further includes: The terminal device receives a second identifier sent by the second network device; wherein the second identifier is carried in the registration acceptance message sent by the second network device, and the second identifier is a temporary identifier associated with the terminal device and the second RAT.

12. The method according to claim 9 or 11, wherein, The method further includes: The terminal device receives a third identifier sent by the second network device; wherein the third identifier is carried in the registration acceptance message sent by the second network device when the terminal device receives the third identifier, and the third identifier is a temporary identifier associated with the terminal device and the first RAT and the second RAT.

13. The method according to any one of claims 1 to 12, wherein, The terminal device is in an idle state.

14. The method according to any one of claims 6 to 13, wherein, The first network device is the core network device of the first RAT; or... The first network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed.

15. The method according to any one of claims 6 to 13, wherein, The second network device is the core network device of the second RAT; or... The second network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed.

16. A communication method applied to a first network device, the method comprising: Send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used for the terminal device to send a service request message or a mobility registration request message.

17. The method according to claim 16, wherein, The mobility registration result of the terminal device on the first network includes one of the following: The registration of the terminal device on the first network is valid; The registration of the terminal device on the first network is invalid.

18. The method according to claim 16 or 17, wherein, The first information is carried in the registration acceptance message sent by the first network device to the terminal device.

19. The method according to claim 18, wherein, The method further includes: Send a first identifier to the terminal device; wherein the first identifier is carried in the registration acceptance message sent by the first network device to the terminal device, and the first identifier is a temporary identifier associated with the terminal device and the first RAT.

20. The method according to any one of claims 16 to 19, wherein, The first network device at least supports the terminal device accessing the second network, and the first network device has the ability to retain context; wherein the first network uses a first RAT, and the second network uses a second RAT.

21. The method according to claim 20, wherein, The method further includes: The terminal device receives a context request message sent by the second network device; wherein the context request message carries a registration request message sent by the terminal device to the second network device.

22. The method according to claim 21, wherein, The method further includes: The first network device sends capability information to the second network device; wherein the capability information indicates the first network device's ability to retain context; the capability information is carried in a context response message sent by the first network device to the second network device.

23. The method according to claim 21 or 22, wherein, The method further includes: The first network device receives indication information sent by the second network device; wherein the indication information is used to enable the first network device to determine whether to retain the session list; the indication information is carried in the context confirmation message sent by the second network device to the first network device.

24. The method according to any one of claims 16 to 23, wherein, The first network device is the core network device of the first RAT; or... The first network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed.

25. The method according to any one of claims 20 to 23, wherein, The second network device is the core network device of the second RAT; or... The second network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed.

26. A communication method applied to a second network device, the method comprising: Send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used for the terminal device to send a service request message or a mobility registration request message.

27. The method according to claim 25, wherein, The mobility registration result of the terminal device on the first network includes one of the following: The registration of the terminal device on the first network is valid; The registration of the terminal device on the first network is invalid.

28. The method according to claim 26, wherein, When the terminal device accesses the second network, the first network device has the ability to retain the context; wherein the first network uses a first RAT and the second network uses a second RAT.

29. The method according to claim 27, wherein, The first information is carried in the registration acceptance message sent by the second network device to the terminal device.

30. The method according to claim 28, wherein, The method further includes: The second network device receives a first identifier sent by the terminal device; wherein the first identifier is carried in a registration request message sent by the terminal device received by the second network device, and the first identifier is a temporary identifier associated with the terminal device and the first RAT.

31. The method according to claim 29, wherein, The method further includes: The first network device is identified based on the first identifier.

32. The method according to any one of claims 29 to 30, wherein, The method further includes: A context request message is sent to the first network device; wherein the context request message carries a registration request message sent by the terminal device to the second network device.

33. The method according to any one of claims 29 to 31, wherein, The method further includes: The second network device receives capability information sent by the first network device; wherein the capability information indicates the first network device's ability to retain context; the capability information is carried in a context response message received by the second network device from the first network device.

34. The method according to any one of claims 28 to 31, wherein, The method further includes: Obtain capability information; wherein the capability information indicates the first network device's ability to retain context.

35. The method according to claim 32 or 33, wherein, The method further includes: Send indication information to the first network device; wherein the indication information is used by the first network device to determine whether to retain the session list; the indication information is carried in a context confirmation message sent by the second network device to the first network device.

36. The method according to any one of claims 32 to 34, wherein, The method further includes: Based on the capability information, it is determined that the first network device does not have the capability to retain context. The indication information is used by the first network device to determine whether to retain the session list.

37. The method according to any one of claims 32 to 34, wherein, The method further includes: Based on the capability information, it is determined that the first network device has the capability to retain context. The indication information is determined to enable the first network device to determine not to retain the session list; or, the indication information is determined to enable the first network device to determine to retain the session list.

38. The method according to any one of claims 28 to 36, wherein, The method further includes: A type indication message is sent to the third network device; wherein the type indication message is used to indicate the supported RAT types; the type indication message is carried in an update request message sent by the second network device to the third network device.

39. The method according to claim 37, wherein, The method further includes: The second network device receives a type confirmation message sent by the third network device; wherein the type confirmation message is used to indicate whether the registration of the first network is available; the type confirmation message is carried in an update response message sent by the third network device received by the second network device.

40. The method according to any one of claims 28 to 38, wherein, The method further includes: Send a second identifier to the terminal device; wherein the second identifier is carried in the registration acceptance message sent by the second network device to the terminal device, and the second identifier is a temporary identifier associated with the terminal device and the second RAT.

41. The method according to any one of claims 28 to 38, wherein, The method further includes: A third identifier is sent to the terminal device; wherein the third identifier is carried in the registration acceptance message sent by the second network device to the terminal device, and the third identifier is a temporary identifier associated with the terminal device and the first RAT and the second RAT.

42. The method according to any one of claims 27 to 40, wherein, The first network device is the core network device of the first RAT; or... The first network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed.

43. The method according to any one of claims 25 to 40, wherein, The second network device is the core network device of the second RAT; or... The second network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed.

44. A communication method applied to a third network device, the method comprising: A type confirmation message is sent to the second network device; wherein the type confirmation message is used to indicate whether the first network is available.

45. The method according to claim 43, wherein, The type confirmation message is carried in the update response message sent by the third network device to the second network device.

46. ​​The method of claim 44, wherein, The method further includes: The third network device receives type indication information sent by the second network device; wherein the type indication message is used to indicate the supported RAT type; the type indication message is carried in the update request message sent by the second network device received by the third network device.

47. The method according to any one of claims 43 to 45, wherein, The second network device is the core network device of the second RAT; or... The second network device is the core network device of the first RAT and the core network device of the second RAT, which are centrally deployed.

48. A communication method applied to a first communication system, the first communication system comprising at least a second network device and a third network device, the method comprising: The second network device sends an update request message to the third network device; wherein the update request message carries a type indication message, which is used to indicate the supported RAT types; The third network device sends an update response message to the second network device; wherein the update response message carries a type confirmation message, which is used to indicate whether the first network is available; the first network uses a first RAT.

49. A communication method applied to a second communication system, the second communication system comprising at least a terminal device and a second network device, the method comprising: The second network device sends first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; wherein the first network uses a first RAT; When the terminal device accesses the first network, it sends a service request message or a mobility registration request message on the first network based on the first information.

50. A communication device applied to a terminal equipment, the device comprising: The first receiving unit is configured to receive the first information; The first sending unit is configured to send a service request message or a mobility registration request message on the first network based on the first information when the terminal device accesses the first network.

51. A communication device applied to a first network device, the device comprising: The second sending unit is configured to send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used by the terminal device to send a service request message or a mobility registration request message.

52. A communication device applied to a second network device, the device comprising: The third sending unit is configured to send first information to the terminal device; wherein the first information at least indicates the mobility registration result of the terminal device on the first network; the mobility registration result of the terminal device on the first network is used for the terminal device to send a service request message or a mobility registration request message.

53. A communication device applied to a third network device, the device comprising: The fourth sending unit is configured to send a type confirmation message to the second network device; wherein the type confirmation message is used to indicate whether the first network is available.

54. A terminal device, comprising: Memory is used to store executable instructions for a computer; A processor, connected to the memory, is configured to implement the method of any one of claims 1 to 15 by executing the computer-executable instructions.

55. A first network device, comprising: Memory is used to store executable instructions for a computer; A processor, connected to the memory, is configured to implement the method of any one of claims 16 to 25 by executing the computer-executable instructions.

56. A second network device, comprising: Memory is used to store executable instructions for a computer; A processor, connected to the memory, is configured to implement the method of any one of claims 26 to 43 by executing the computer-executable instructions.

57. A third network device, comprising: Memory is used to store executable instructions for a computer; A processor, connected to the memory, is configured to implement the method of any one of claims 44 to 47 by executing the computer-executable instructions.

58. A chip, the chip comprising: A processor for retrieving and running a computer program from memory, causing a device having the chip mounted to perform the method as described in any one of claims 1 to 15, or the method as described in any one of claims 16 to 25, or the method as described in any one of claims 26 to 43, or the method as described in any one of claims 44 to 47.

59. A computer-readable storage medium storing a computer program that, when executed by at least one processor, implements the method as claimed in any one of claims 1 to 15, or implements the method as claimed in any one of claims 16 to 25, or implements the method as claimed in any one of claims 26 to 43, or implements the method as claimed in any one of claims 44 to 47.

60. A computer program product comprising a computer storage medium storing a computer program, the computer program comprising instructions executable by at least one processor, wherein when the instructions are executed by the at least one processor, the method of any one of claims 1 to 15 is implemented, or the method of any one of claims 16 to 25 is implemented, or the method of any one of claims 26 to 43 is implemented, or the method of any one of claims 44 to 47 is implemented.

61. A computer program that causes a computer to perform the method as claimed in any one of claims 1 to 15, or to implement the method as claimed in any one of claims 16 to 25, or to implement the method as claimed in any one of claims 26 to 43, or to implement the method as claimed in any one of claims 44 to 47.

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