Communication method and apparatus

Abstract

The present application provides a communication method and apparatus. The method comprises: a second network element sends a public land mobile network priority list of a first terminal to a third network element, wherein the third network element is responsible for mobility management or access management of the first terminal; and when the first terminal is associated with a second terminal, the second network element sends second instruction information to the third network element, wherein the second instruction information is used for instructing the first terminal to select a public land mobile network different from a public land mobile network selected by the second terminal, and the public land mobile network selected by the first terminal belongs to the public land mobile network priority list of the first terminal. By using the method, the first terminal and the second terminal can select different public land mobile networks. When the first terminal and the second terminal access different public land mobile networks, the first terminal and the second terminal serve as backups for each other.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on February 8, 2024, with application number 202410178217.5 and invention name "A Communication Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

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

[0004] With the development of communication technology, future mobile communication devices may include two user equipment (UE) or two universal subscriber identity modules (USIM). The mobile communication device can connect to two radio access networks (RAN) through the two UEs or two USIMs, and the mobile communication device transmits service data through the two RANs.

[0005] Currently, how the mobile communication device selects a network is an issue worthy of attention. Summary of the Invention

[0006] Embodiments of the present application provide a communication method and apparatus for enabling a mobile communication device including two UEs or two USIMs to select a network.

[0007] In a first aspect, the present application provides a communication method, which is applied to a first network element or a device having the function of a first network element (such as a chip, etc.), the method comprising: receiving a first request message from a second network element, the first request message being used to request network selection information of a first terminal, the first request message including an identifier of the first terminal and first indication information, the first indication information being used to indicate that the first terminal is associated with the second terminal; determining the public land mobile network priority list of the first terminal based on the first indication information and the public land mobile network priority list of the second terminal, or determining the public land mobile network priority list of the first terminal based on the first indication information and the identifier of the second public land mobile network, the second public land mobile network providing services for the second terminal; and sending a first response message to the second network element, the first response message including the public land mobile network priority list of the first terminal.

[0008] With the above design, the first network element can determine the public land mobile network priority list of the first terminal based on the first indication information and the public land mobile network priority list of the second terminal, or determine the public land mobile network priority list of the first terminal based on the first indication information and the identifier of the second public land mobile network, so as to allow the first terminal and the second terminal to select different public land mobile networks as much as possible. The first terminal and the second terminal accessing different public land mobile networks can enable the first terminal and the second terminal to back up each other. For example, when the first terminal loses connection with the public land mobile network to which it is connected, data can be transferred to the public land mobile network to which the second terminal is connected for transmission.

[0009] In one possible design, the first indication information includes an identifier of the second terminal.

[0010] In one possible design, before determining the public land mobile network priority list of the first terminal based on the first indication information and the identifier of the second public land mobile network, the identifier of the second public land mobile network is received from the second network element.

[0011] In one possible design, a public land mobile network priority list of the second terminal is sent to the second network element.

[0012] In one possible design, the first terminal and the second terminal are in the same dual-directional device.

[0013] In a second aspect, the present application provides a communication method, which is applied to a second network element or a device having the function of a second network element (such as a chip, etc.), the method comprising: sending a first request message to a first network element, the first request message being used to request network selection information of a first terminal, the first request message including an identifier of the first terminal and first indication information, the first indication information being used to indicate that the first terminal is associated with the second terminal; and receiving a first response message from the first network element, the first response message including a public land mobile network priority list of the first terminal.

[0014] With the above design, the public land mobile network priority list of the first terminal obtained from the first network element allows the first terminal and the second terminal to select different public land mobile networks as much as possible. The first terminal and the second terminal access different public land mobile networks so that the first terminal and the second terminal can back up each other.

[0015] In one possible design, the first indication information includes an identifier of the second terminal.

[0016] In one possible design, an identifier of a second public land mobile network is sent to the first network element, and the second public land mobile network provides service for the second terminal.

[0017] In one possible design, a public land mobile network priority list for the second terminal is received from the first network element.

[0018] In one possible design, when the first public land mobile network and the second public land mobile network are the same, the first request message is sent to the first network element; wherein the first public land mobile network provides services for the first terminal, and the second public land mobile network provides services for the second terminal.

[0019] With the above design, if the first public land mobile network and the second public land mobile network are different, the second network element may not need to send the first request message to the first network element. When the first public land mobile network and the second public land mobile network are the same, the second network element sends the first request message to the first network element, thereby saving signaling overhead.

[0020] In one possible design, the first terminal and the second terminal are in the same dual-directional device.

[0021] In a third aspect, the present application provides a communication method, applied to a second network element or a device having the functions of a second network element (such as a chip, etc.), the method comprising: sending a public land mobile network priority list of a first terminal to a third network element, wherein the third network element is responsible for mobility management or access management of the first terminal; when the first terminal is associated with the second terminal, sending second indication information to the third network element, the second indication information being used to instruct the first terminal to select a public land mobile network different from the public land mobile network selected by the second terminal, and the public land mobile network selected by the first terminal belongs to the public land mobile network priority list of the first terminal.

[0022] With the above design, by sending the second indication information to the first device, the first terminal and the second terminal can select different public land mobile networks. The first terminal and the second terminal access different public land mobile networks, so that the first terminal and the second terminal can back up each other.

[0023] In one possible design, a third indication message is sent to a fourth network element, where the third indication message is used to instruct the second terminal to give priority to a public land mobile network, or the second terminal is the main terminal in the first device, the first terminal and the second terminal are in the first device, and the fourth network element is responsible for the mobility management or access management of the second terminal.

[0024] With the above design, by sending the third indication information to the first device, the second terminal can select the public land mobile network before the first terminal.

[0025] In a fourth aspect, the present application provides a communication method, applied to a first device or a device having the functions of the first device (such as a chip, etc.), wherein the first device includes: a first terminal and a second terminal. The method includes: receiving a public land mobile network priority list and second indication information of the first terminal, the second indication information being used to instruct the first terminal to select a public land mobile network different from the public land mobile network selected by the second terminal; and determining a first public land mobile network from the public land mobile network priority list of the first terminal based on the second indication information and the identifier of the second public land mobile network, the second public land mobile network being the public land mobile network selected by the second terminal, or the second public land mobile network providing services for the second terminal, the first public land mobile network being different from the second public land mobile network.

[0026] With the above design, the first device determines the first public land mobile network from the first terminal's public land mobile network priority list based on the second indication information and the identifier of the second public land mobile network selected by the second terminal. The first public land mobile network is different from the second public land mobile network, thereby enabling the first terminal and the second terminal to select different public land mobile networks. The first terminal and the second terminal access different public land mobile networks, allowing the first terminal and the second terminal to serve as backups for each other.

[0027] In one possible design, fourth indication information is received, where the fourth indication information indicates whether the first public land mobile network supports dual-directional capability; when the fourth indication information indicates that the first public land mobile network does not support dual-directional capability, a third public land mobile network is determined from the public land mobile network priority list of the first terminal, where the third public land mobile network is different from the second public land mobile network and different from the first public land mobile network.

[0028] With the above design, the first device can learn whether the first public land mobile network supports the dual-directional capability, and reselect a public land mobile network when the first public land mobile network does not support the dual-directional capability.

[0029] In one possible design, a third indication information is received, wherein the third indication information is used to indicate that the second terminal prioritizes a public land mobile network or that the second terminal is the main terminal in the first device; a public land mobile network priority list of the second terminal is received; and the second public land mobile network is selected from the public land mobile network priority list of the second terminal according to the third indication information.

[0030] With the above design, the second terminal can select the public land mobile network according to the third indication information, and earlier than the first terminal selects the public land mobile network.

[0031] In a fifth aspect, the present application provides a communication method, which is applied to a second network element or a device having the function of a second network element (such as a chip, etc.), the method comprising: when the first terminal is associated with the second terminal and the first public land mobile network is the same as the second public land mobile network, sending fifth indication information to a third network element, wherein the first public land mobile network provides services for the first terminal, the second public land mobile network provides services for the second terminal, and the fifth indication information instructs the first terminal to reselect the public land mobile network, and / or the type of the public land mobile network selected by the first terminal.

[0032] With the above design, when the first terminal and the second terminal select the same public land mobile network, by triggering either the first terminal or the second terminal to reselect the public land mobile network and / or indicating the type of the selected public land mobile network, the first terminal and the second terminal can select different public land mobile networks. The first terminal and the second terminal access different public land mobile networks, so that the first terminal and the second terminal can serve as backups for each other.

[0033] In one possible design, the type of the public land mobile network is a visited public land mobile network or an equivalent public land mobile network.

[0034] In a sixth aspect, the present application provides a communication method, applied to a first terminal or a device having the functions of a first terminal (such as a chip, etc.), the method comprising: receiving fifth indication information, the fifth indication information instructing the first terminal to reselect a public land mobile network, and / or the type of public land mobile network selected by the first terminal; determining a fourth public land mobile network in the public land mobile network priority list of the first terminal according to the fifth indication information.

[0035] With the above design, the first terminal reselects the public land mobile network according to the fifth indication information, so that the first terminal and the second terminal select different public land mobile networks.

[0036] In one possible design, the type of the public land mobile network is a visited public land mobile network or an equivalent public land mobile network.

[0037] In the seventh aspect, the present application provides a communication method, which is applied to a first network element or a device having the function of a first network element (such as a chip, etc.), the method comprising: receiving a second request message from a second network element, the second request message being used to request network selection information of a first terminal, the second request message including an identifier of the first terminal and first indication information, the first indication information being used to indicate that the first terminal is associated with the second terminal; determining the access technology priority list of the first terminal based on the first indication information and the access technology priority list of the second terminal; and sending a second response message to the second network element, the second response message including the access technology priority list of the first terminal.

[0038] Using the above method, the first network element determines the access technology priority list of the first terminal based on the first indication information and the access technology priority list of the second terminal, so as to allow the first terminal and the second terminal to access the network or the same public land network through different access technologies as much as possible. The first terminal and the second terminal that access the network through different access technologies can back up each other.

[0039] In one possible design, the first indication information includes an identifier of the second terminal.

[0040] In one possible design, an access technology priority list of the second terminal is sent to the second network element.

[0041] In one possible design, the first terminal and the second terminal are in the same dual-directional device.

[0042] In one possible design, the access technology in the access technology priority list of the first terminal and the access technology in the access technology priority list of the second terminal are used to access the same public land mobile network.

[0043] In an eighth aspect, the present application provides a communication method, which is applied to a second network element or a device having the function of a second network element (such as a chip, etc.), the method comprising: sending a second request message to a first network element, the second request message being used to request network selection information of a first terminal, the second request message comprising an identifier of the first terminal and first indication information, the first indication information being used to indicate that the first terminal is associated with the second terminal; receiving a second response message from the first network element, the second response message comprising an access technology priority list of the first terminal.

[0044] By using the above method, the access technology priority list of the first terminal obtained from the first network element can enable the first terminal and the second terminal to access the network or the same public land network through different access technologies as much as possible, and the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0045] In one possible design, the first indication information includes an identifier of the second terminal.

[0046] In one possible design, an access technology priority list for the second terminal is received from the first network element.

[0047] In one possible design, the first terminal and the second terminal are in the same dual-directional device.

[0048] In one possible design, the access technology in the access technology priority list of the first terminal and the access technology in the access technology priority list of the second terminal are used to access the same public land mobile network.

[0049] In the ninth aspect, the present application provides a communication method, which is applied to a second network element or a device having the function of a second network element (such as a chip, etc.), the method comprising: when a first terminal is associated with a second terminal, determining the contracted wireless access technology or frequency selection priority index of the first terminal and the contracted wireless access technology or frequency selection priority index of the second terminal, wherein the contracted wireless access technology or frequency selection priority index of the first terminal and the contracted wireless access technology or frequency selection priority index of the second terminal are different; sending the contracted wireless access technology or frequency selection priority index of the first terminal to a third network element, and the third network element is responsible for the mobility management or access management of the first terminal; sending the contracted wireless access technology or frequency selection priority index of the second terminal to a fourth network element, and the fourth network element is responsible for the mobility management or access management of the second terminal.

[0050] Using the above method, when the first terminal is associated with the second terminal, the second network element can determine the contracted wireless access technology or frequency selection priority index of the first terminal and the contracted wireless access technology or frequency selection priority index of the second terminal, which are different from each other, so as to allow the first terminal and the second terminal to access the network or the same public land network through different access technologies as much as possible, and then the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0051] In the tenth aspect, the present application provides a communication method, which is applied to a second network element or a device having the function of a second network element (such as a chip, etc.), the method comprising: receiving first information from a third network element, the first information indicating a first wireless access technology or frequency selection priority index and / or a first access type, the first wireless access technology or frequency selection priority index is the wireless access technology or frequency selection priority index determined by the third network element for the first terminal, and the first access type is the access type corresponding to the access network device accessed by the first terminal; the third network element is responsible for the mobility management or access management of the first terminal; when the first terminal is associated with the second terminal, the contracted wireless access technology or frequency selection priority index of the second terminal is determined according to the first information; and the contracted wireless access technology or frequency selection priority index of the second terminal is sent to the fourth network element, and the fourth network element is responsible for the mobility management or access management of the second terminal.

[0052] Using the above method, the second network element can determine the contracted wireless access technology or frequency selection priority index of the second terminal based on the first information after obtaining the first information and when the first terminal is associated with the second terminal, so as to allow the first terminal and the second terminal to access the network or the same public land network through different access technologies as much as possible, and thus the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0053] In one possible design, when determining the contracted wireless access technology or frequency selection priority index of the second terminal based on the first information, the initial contracted wireless access technology or frequency selection priority index of the second terminal is updated according to the first information to determine the contracted wireless access technology or frequency selection priority index of the second terminal.

[0054] In one possible design, the first information indicates a first wireless access technology or a frequency selection priority index; and sixth indication information is sent to the third network element, where the sixth indication information is used to request the first information.

[0055] In an eleventh aspect, the present application provides a communication method, applied to a second network element or a device having the function of a second network element (such as a chip, etc.), the method comprising: receiving first information from a third network element, the first information indicating a first radio access technology or frequency selection priority index and / or a first access type, the first radio access technology or frequency selection priority index being a radio access technology or frequency selection priority index determined by the third network element for a first terminal, and the first access type being an access type corresponding to an access network device accessed by the first terminal; the third network element being responsible for mobility management or access management of the first terminal; when the first terminal is associated with a second terminal, sending second information to a fourth network element, the second information including third information and / or the contracted radio access technology or frequency selection priority index of the first terminal, wherein the third information is determined based on the first radio access technology or frequency selection priority index and / or the first access type; or, the second information including at least one of the first radio access technology or frequency selection priority index, the first access type, or the contracted radio access technology or frequency selection priority index of the first terminal, and the fourth network element being responsible for mobility management or access management of the second terminal.

[0056] Using the above method, the second network element can send the second information to the network element responsible for the mobility management or access management of the second terminal (i.e., the fourth network) after obtaining the first information and when the first terminal is associated with the second terminal, so that the fourth network element can determine the wireless access technology or frequency selection priority index for the second terminal in combination with the second information, so as to enable the first terminal and the second terminal to access the network or the same public land network through different access technologies as much as possible, and thus the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0057] In one possible design, fourth information is received from the fourth network element, where the fourth information indicates a second wireless access technology or frequency selection priority index and / or a second access type, where the second wireless access technology or frequency selection priority index is the wireless access technology or frequency selection priority index determined by the fourth network element for the second terminal, and the second access type is the access type corresponding to the access network device accessed by the second terminal; when the first terminal is associated with the second terminal, and the first wireless access technology or frequency selection priority is the same as the second wireless access technology or frequency selection priority index and / or the first access type is the same as the second access type, the second information is sent to the fourth network element.

[0058] With the above design, when the wireless access technology or frequency selection priority index corresponding to the first terminal and the second terminal is different or the access type is different, the second network element may not send the second information to the fourth network element. When the wireless access technology or frequency selection priority index corresponding to the first terminal and the second terminal is the same and / or the access type is the same, the second network element sends the second information to the fourth network element, which can save signaling overhead.

[0059] In one possible design, the subscribed radio access technology or frequency selection priority index of the second terminal is sent to the fourth network element.

[0060] In one possible design, the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type. If the first information includes the first access type, the third information includes a fourth access type, and the fourth access type is different from the first access type; and / or, if the first information includes the first wireless access technology or frequency selection priority index, the third information includes a fourth wireless access technology or frequency selection priority index, and the fourth wireless access technology or frequency selection priority index is different from the first wireless access technology or frequency selection priority index.

[0061] With the above design, the third information may suggest or recommend an access type or a wireless access technology or a frequency selection priority index for the fourth network element.

[0062] In one possible design, first indication information is sent to the fourth network element, where the first indication information is used to indicate that the first terminal is associated with the second terminal.

[0063] In a twelfth aspect, the present application provides a communication method, applied to a fourth network element or a device (such as a chip, etc.) having the function of a fourth network element, the method comprising:

[0064] Receive second information from a second network element, the second information including third information and / or the contracted wireless access technology or frequency selection priority index of the first terminal, wherein the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type, or the second information includes at least one of the first wireless access technology or frequency selection priority index, the first access type or the contracted wireless access technology or frequency selection priority index of the first terminal; wherein the first wireless access technology or frequency selection priority index is the wireless access technology or frequency selection priority index determined by the third network element for the first terminal, the first access type is the access type corresponding to the access network device accessed by the first terminal, and the third network element is responsible for the mobility management or access management of the first terminal; determine the third wireless access technology or frequency selection priority index based on the contracted wireless access technology or frequency selection priority index of the second terminal and the second information; and send the third wireless access technology or frequency selection priority index to the access network device accessed by the second terminal.

[0065] Using the above method, the fourth network element can determine the wireless access technology or frequency selection priority index for the second terminal based on the second information and the contracted wireless access technology or frequency selection priority index of the second terminal, so as to enable the first terminal and the second terminal to access the network or the same public land network through different access technologies as much as possible, and then the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0066] In one possible design, first indication information is received from the second network element, and the first indication information is used to indicate that the first terminal is associated with the second terminal; when determining a third wireless access technology or frequency selection priority index based on the contracted wireless access technology or frequency selection priority index of the second terminal and the second information, the third wireless access technology or frequency selection priority index is determined based on the first indication information, the contracted wireless access technology or frequency selection priority index of the second terminal and the second information.

[0067] Using the above design, the fourth network element can know that the first terminal is associated with the second terminal, and then determine the wireless access technology or frequency selection priority index for the second terminal based on the first indication information, the second information and the contracted wireless access technology or frequency selection priority index of the second terminal.

[0068] In one possible design, the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type, wherein the third information includes a fourth access type, which is different from the first access type; and / or the third information includes a fourth wireless access technology or frequency selection priority index, which is different from the first wireless access technology or frequency selection priority index.

[0069] In one possible design, a subscribed radio access technology or frequency selection priority index of the second terminal is received from the second network element.

[0070] In one possible design, fourth information is sent to the second network element, where the fourth information indicates a second wireless access technology or frequency selection priority index and / or a second access type. The second wireless access technology or frequency selection priority index is the wireless access technology or frequency selection priority index determined by the fourth network element for the second terminal, and the second access type is the access type corresponding to the access network device accessed by the second terminal.

[0071] In a thirteenth aspect, the present application provides a communication method, which is applied to a fifth network element or a device having the function of a fifth network element (such as a chip, etc.), the method comprising: obtaining the contracted wireless access technology or frequency selection priority index of the second terminal and the second information, the second information comprising third information and / or the contracted wireless access technology or frequency selection priority index of the first terminal, wherein the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type, or the second information comprises at least one of the first wireless access technology or frequency selection priority index, the first access type or the contracted wireless access technology or frequency selection priority index of the first terminal; In the embodiment, the first wireless access technology or frequency selection priority index is the wireless access technology or frequency selection priority index determined by the third network element for the first terminal, the first access type is the access type corresponding to the access network device accessed by the first terminal, and the third network element is responsible for the mobility management or access management of the first terminal; the authorized wireless access technology or frequency selection priority index of the second terminal is determined according to the contracted wireless access technology or frequency selection priority index of the second terminal and the second information; the authorized wireless access technology or frequency selection priority index of the second terminal is sent to the fourth network element, and the fourth network element is responsible for the mobility management or access management of the second terminal.

[0072] Using the above method, after obtaining the contracted wireless access technology or frequency selection priority index and the second information of the second terminal, the fifth network element determines the authorized wireless access technology or frequency selection priority index based on the contracted wireless access technology or frequency selection priority index and the second information of the second terminal, so as to enable the first terminal and the second terminal to access the network or the same public land network through different access technologies as much as possible, and then the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0073] In one possible design, first indication information is received from the second network element, where the first indication information is used to indicate that the first terminal is associated with the second terminal; when determining the authorized wireless access technology or frequency selection priority index of the second terminal based on the contracted wireless access technology or frequency selection priority index of the second terminal and the second information, the authorized wireless access technology or frequency selection priority index of the second terminal is determined based on the first indication information, the contracted wireless access technology or frequency selection priority index of the second terminal and the second information.

[0074] Using the above design, the fifth network element can know that the first terminal is associated with the second terminal, and then can select the authorized access technology or frequency selection priority index based on the first indication information, the second information and the contracted wireless access technology or frequency selection priority index of the second terminal.

[0075] In one possible design, the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type, wherein, if the first information includes the first access type, the third information includes a fourth access type, and the fourth access type is different from the first access type; and / or, if the first information includes the first wireless access technology or frequency selection priority index, the third information includes a fourth wireless access technology or frequency selection priority index, and the fourth wireless access technology or frequency selection priority index is different from the first wireless access technology or frequency selection priority index.

[0076] In one possible design, when obtaining the contracted wireless access technology or frequency selection priority index and the second information of the second terminal, the contracted wireless access technology or frequency selection priority index and the second information of the second terminal are received from the fourth network element.

[0077] In one possible design, when obtaining the contracted wireless access technology or frequency selection priority index and the second information of the second terminal, the contracted wireless access technology or frequency selection priority index of the second terminal is received from the fourth network element; and the second information is received from the second network element, and the second network element is used for data management of the second terminal.

[0078] In the fourteenth aspect, the present application provides a communication device, which can be a first device, or a module or unit (for example, a chip, or a chip system, or a circuit) in the first device that corresponds one-to-one to the method / operation / step / action described in any one of the first to second aspects, or can be used in combination with the first device.

[0079] In the fifteenth aspect, the present application provides a communication device comprising at least one processing element, wherein at least one storage element is used to store programs and data, and the at least one processing element is used to read and execute the programs and data stored in the storage element so that the method described in any one of the above aspects of the present application is implemented.

[0080] In one possible design, the communication device further includes the at least one storage element.

[0081] In the sixteenth aspect, the present application also provides a computer program, which, when executed on a computer, enables the computer to execute any of the methods described in any of the above aspects.

[0082] In the seventeenth aspect, the present application provides a communication device, which includes: an interface circuit and at least one processor; the interface circuit is used to provide input and / or output of programs or instructions to the at least one processor; the at least one processor is used to execute the program or instructions so that the communication device can implement any method described in any of the above aspects.

[0083] In one possible manner, the communication device includes the at least one memory, and the at least one memory is used to store the program or instruction.

[0084] In an eighteenth aspect, the present application provides a computer storage medium storing a software program. When the software program is read and executed by one or more processors, the software program can implement any of the methods described in any of the above aspects.

[0085] In a nineteenth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute any of the methods described in any of the above aspects.

[0086] In the twentieth aspect, the present application provides a chip system, which includes at least one chip and a memory, and the at least one chip is used to read and execute the program stored in the memory to implement any method described in any one of the above aspects.

[0087] In aspect 21, the present application provides a communications system, comprising one or more of a first network element, a second network element, a third network element, a fourth network element, a fifth network element, a first device, a first terminal, and a second terminal, wherein the first network element is configured to perform the method described in any one of aspect 1 or aspect 7, and the second network element is configured to perform the method described in any one of aspect 2, aspect 3, aspect 5, aspect 8, aspect 9, aspect 10, and aspect 11. The fourth network element is configured to perform the method described in aspect 12. The fifth network element is configured to perform the method described in aspect 13. The first device is configured to perform the method described in aspect 4. The first terminal is configured to perform the method described in aspect 6.

[0088] Based on the implementations provided in the above aspects, this application can also be further combined to provide more implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 shows a schematic diagram of a 5G network architecture based on a service-oriented architecture;

[0090] FIG2 is a schematic diagram showing a RAN obtaining an RFSP index;

[0091] FIG3 shows a schematic diagram of a dual-directional device connected to different RANs via two terminals;

[0092] FIG4 shows a schematic diagram of a communication method corresponding to Example 1;

[0093] FIG5 is a schematic diagram showing a communication method corresponding to Example 2;

[0094] FIG6 shows a schematic diagram of a communication method corresponding to Example 3;

[0095] FIG7 shows a schematic diagram of a communication method corresponding to Example 4;

[0096] FIG8 is a schematic diagram showing a communication method corresponding to Example 5;

[0097] FIG9 shows a schematic diagram of a communication method corresponding to Example 6;

[0098] FIG10 is a schematic diagram showing a communication method corresponding to Example 7;

[0099] FIG11 is a schematic diagram showing a communication method corresponding to Example 8;

[0100] FIG12 is a schematic diagram showing a communication method corresponding to Example 9;

[0101] FIG13 shows a schematic diagram of a communication device;

[0102] FIG14 shows a schematic diagram of another communication device. DETAILED DESCRIPTION

[0103] The specific implementation of the present application is described below with reference to the accompanying drawings in the embodiments of the present application. However, the implementation of the present application may also include combining these embodiments without departing from the spirit or scope of the present application, such as adopting other embodiments and making structural changes. Therefore, the detailed description of the following embodiments should not be understood in a restrictive sense. The terms used in the examples section of the present application are only used to explain the specific embodiments of the present application and are not intended to limit the present application.

[0104] The embodiments of the present application can be applied to various communication systems, such as: global system for mobile communications (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), world-wide interoperability for microwave access (WIMAX) communication system, fifth generation (5G) system or new radio (NR), or applied to future communication systems or other similar communication systems.

[0105] Figure 1 is a schematic diagram of a 5G network architecture based on a service-oriented architecture. The 5G network architecture shown in Figure 1 may include terminal devices, access network devices, and core network devices. The terminal device accesses the data network (DN) through the access network device and the core network device. Among them, the core network device includes a variety of network functions (NFs) or network elements, for example, including some or all of the following network elements: unified data management (UDM) network element, unified data repository (UDR) network element, application function (AF) network element, policy control function (PCF) network element, access and mobility management function (AMF) network element, session management function (SMF) network element, user plane function (UPF) network element, network repository function (NRF) network element, network slice selection function (NSSF) network element, authentication server function (AUSF) network element, etc.

[0106] The access network device may be a radio access network (RAN) device. For example: a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next generation NodeB (gNB) in a 5G mobile communication system, a next generation base station in a sixth generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a wireless fidelity (WiFi) system, etc.; it may also be a module or unit that performs part of the functions of a base station, for example, a centralized unit (CU) or a distributed unit (DU). The radio access network device may be a macro base station, a micro base station or an indoor station, a relay node or a donor node, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the radio access network device.

[0107] Terminal devices can be user equipment (UE), mobile stations, mobile terminals, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminal devices can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, urban air vehicles (such as drones and helicopters), ships, robots, robotic arms, smart home devices, etc.

[0108] Access network equipment and terminal devices can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; or in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of access network equipment and terminal devices.

[0109] The following is a brief introduction to some core network equipment:

[0110] The AMF network element, referred to as AMF, performs functions such as mobility management and access authentication / authorization. It is also responsible for transmitting user policies between terminal devices and the PCF.

[0111] The SMF network element, referred to as SMF, includes functions such as session management, execution of control policies issued by PCF, selection of UPF, and allocation of Internet Protocol (IP) addresses for terminal devices.

[0112] The UPF network element, referred to as UPF, serves as the interface with the data network and includes functions such as user plane data forwarding, session / flow-level billing statistics, and bandwidth limitation.

[0113] UDM network element, referred to as UDM, includes functions such as executing and managing contract data and user access authorization.

[0114] The UDR network element, referred to as UDR, includes the access functions of executing contract data, policy data, application data and other types of data.

[0115] NEF network element, referred to as NEF, is used to support the opening of capabilities and events.

[0116] The AF network element, abbreviated as AF, conveys the application side's requirements to the network side, such as quality of service (QoS) requirements or user status event subscriptions. The AF can be a third-party functional entity or an application server deployed by the operator.

[0117] The PCF network element, referred to as PCF, includes policy control functions such as session and service flow level billing, QoS bandwidth guarantee and mobility management, and terminal device policy decision-making.

[0118] NRF network elements, or NRF for short, can be used to provide network element discovery capabilities. Based on requests from other network elements, they provide network element information corresponding to the network element type. NRF network elements also provide network element management services, such as network element registration, update, and deregistration, as well as network element status subscription and push notification.

[0119] NSSF network element: Mainly responsible for network slice selection, and determines the network slice instance that the terminal is allowed to access based on the terminal's slice selection auxiliary information, contract information, etc.

[0120] AUSF network element: supports access authentication of the 3rd Generation Partnership Project (3GPP) and non-3GPP.

[0121] It can be understood that the above network elements are examples of one implementation method, and this application does not exclude the existence of network elements or devices with the above network element functions in 6G or newer wireless communication systems that have other names or other forms.

[0122] It is understood that the above-mentioned network element or function can be a network element in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). As a possible implementation method, the above-mentioned network element or function can be implemented by a single device, or can be implemented by multiple devices together, or can be a functional module within a single device, which is not specifically limited in the embodiments of the present application.

[0123] In this application, network selection includes public land mobile network (PLMN) selection and / or radio access technology (RAT) selection.

[0124] The following is a brief introduction to the existing network options:

[0125] 1. About PLMN Selection

[0126] First, when the terminal is turned on, it is necessary to determine whether the terminal has a SIM card. If the terminal does not have a SIM card or the SIM card of the terminal is unavailable, the terminal is in the No SIM card (NO SIM) state. At this time, it is necessary to wait for the SIM card to be available before network selection can be performed.

[0127] If the current SIM card of the terminal is available, the terminal needs to determine whether there is a registered PLMN (RPLMN), that is, the PLMN registered last time. When the terminal has an RPLMN, it will first try to initiate registration from the RPLMN. The RPLMN information can be saved in the SIM card or in the terminal.

[0128] If the terminal selects RPLMN, it will try to register with the RPLMN. If the registration is successful, the terminal will know which PLMN is selected and enter the ON PLMN state.

[0129] If the terminal does not have RPLMN, or RPLMN registration fails, it will select a network according to the network selection list, and try to register in order according to the priority of the network selection list. If registration is successful, it will enter the online state. If registration fails, and there are still networks in the network selection list that have not been tried, it will continue to try to register according to the network selection list. If registration fails and there is no network to be selected in the network selection list, the terminal will determine whether there is an available PLMN. If so, it will try to register. If not, it will enter the waiting state.

[0130] When the terminal is online, the following situations may trigger network reselection:

[0131] 1. If the terminal is currently connected to a visited PLMN (VPLMN), the terminal will periodically perform network reselection. After a period, the terminal will search for a higher-priority network. If no higher-priority network appears, the terminal will maintain the current network status. If a higher-priority network appears, the terminal will select the higher-priority network and attempt to access it.

[0132] 2. When the network currently connected to the terminal loses coverage, the terminal will determine whether there is an available network access. If there is an available network, the terminal will select the network according to priority. If not, the terminal will enter the waiting state. If the last registered network is available at this time, the terminal will resume the online state. If other available networks appear, the terminal will select the network access according to priority.

[0133] 3. The user can manually trigger network reselection. At this time, the terminal will add the last registered network to the temporarily banned list, and then reselect the network according to the network selection list.

[0134] 4. If the terminal receives a roaming prohibition instruction and the terminal is currently connected to a VPLMN, the terminal is triggered to perform network reselection.

[0135] Exemplarily, the network selection list can be an operator controlled PLMN selector with access technology. As shown in Table 1, 1st represents the PLMN with the highest priority, and the access technology is used by the terminal to determine what type of wireless carrier to use to search for the corresponding PLMN. The access technology can specifically be a RAT type. For example, the RAT type can include evolved universal terrestrial radio access (E-UTRA), 5GNR, 5G NR (satellite), 6G RAT, etc. M is the abbreviation of Mandatory, which means mandatory, and O is the abbreviation of Optional, which means optional.

[0136] Table 1

[0137] The terminal can obtain the network selection list through the steering of roaming (SOR) process. The SOR process can be divided into two types: the SOR process initiated during the registration process and the SOR process triggered after the registration process.

[0138] (1) SOR process initiated during the terminal registration process: If the user contract information indicates that SOR is triggered when the terminal initially registers to the VPLMN, then when the terminal initially registers in the VPLMN, the home PLMN (HPLMN) UDM triggers the SOR process, or the HPLMN UDM can trigger the SOR process based on the operator policy. The HPLMN UDM provides the SOR to the terminal through the AMF when the terminal registers in the VPLMN. The SOR includes the terminal's network selection list, where the HPLMN UDM can obtain the terminal's network selection list from the Steering of Roaming Application Function (SOR AF). The terminal performs security verification on the received network selection list. If the verification is successful, the terminal re-executes network selection based on the received network selection list and selects the network access with a high priority.

[0139] (2) SOR process triggered after the registration process: The HPLMN UDM obtains the updated network selection list; for example, the SOR AF sends the updated network selection list to the HPLMN UDM, or the HPLMN UDM requests the updated network selection list from the SOR AF, and the SOR AF sends the updated network selection list to the HPLMN UDM. The HPLMN UDM sends the updated network selection list to the terminal through the AMF. The terminal performs security verification on the received network selection list. If the verification is successful, the terminal uploads the network selection list to the USIM card or replaces the network selection list stored in the terminal device.

[0140] 2. About RAT Selection

[0141] (1) The terminal determines the RAT based on the network selection list

[0142] When a terminal searches for a PLMN, the network (e.g., RAN) can control the access technology so that the terminal determines what type of wireless carrier to use to search for the corresponding PLMN. For example, as shown in Table 1 above, when the terminal searches for the first PLMN, if E-UTRA has a higher priority than 5G NR, the terminal first searches the wireless carrier corresponding to E-UTRA and then searches the wireless carrier corresponding to 5G NR. If a wireless carrier corresponding to E-UTRA (e.g., a synchronization signal) is found, the terminal accesses the first PLMN through the radio access network device corresponding to E-UTRA. Otherwise, the terminal continues to search for the wireless carrier corresponding to 5G NR.

[0143] (2) RAN determines RAT based on RFSP

[0144] The AMF provides the RAT / Frequency selection priority (RFSP) index to the RAN. The RAN maps the RFSP index to a local management policy, such as directing a connected terminal to another frequency or a different RAT, or prioritizing an idle terminal to reside on a specific frequency or a specific RAT. The RFSP index (or RFSP index value) can be understood as the RAT priority. For example, RFSP#1 indicates that E-UTRA is superior to 5G NR (i.e., priority access to E-UTRA), and RFSP#2 indicates that 5G NR is superior to E-UTRA (i.e., priority access to 5G NR).

[0145] For example, with reference to FIG2 , the RAN may obtain the RFSP index in the following two ways:

[0146] Method 1: During the terminal registration process, the AMF obtains the subscribed RFSP index (subscribed RFSPIndex) of the terminal from the UDM. The AMF can set the subscribed RFSP index to the RFSP index in use (RFSPIndex in use), or the AMF generates the RFSP index in use based on the local operator's configuration and the subscribed RFSP index. The AMF sends the RFSP index in use to the RAN to which the terminal is connected.

[0147] Method 2: During the terminal registration process, AMF obtains the contracted RFSP index of the terminal from UDM. AMF sends the contracted RFSP index to PCF. PCF can determine the authorized RFSP index (authorized RFSP index) at any time based on the contracted RFSP index. For example, the current 5G NR is congested. In order to control the terminal to access E-UTRA first, PCF can set the contracted RFSP index to RFSP#1. For example, RFSP#1 indicates that E-UTRA is superior to 5G NR (i.e., priority access to E-UTRA). PCF sends the authorized RFSP index to AMF. AMF sets the authorized RFSP index to the RFSP index in use or AMF generates the RFSP index in use based on the local operator's configuration and the authorized RFSP index. AMF sends the RFSP index in use to the RAN to which the terminal is connected.

[0148] The following embodiments are described using only two terminals (ie, a first terminal and a second terminal) as an example. It is understandable that the following embodiments can also be applied to scenarios in which three or more terminals are associated, which will not be described in detail here.

[0149] For example, the first terminal and the second terminal may be in the same device, for example, a dual-steer device with dual-steer capabilities. Alternatively, the first terminal and the second terminal may be devices of the same user, for example, user A's mobile phone and user A's car terminal, or user B's mobile phone and user B's tablet computer. Alternatively, the first terminal and the second terminal may be two SIM cards corresponding to the same mobile communication device.

[0150] The first terminal and the second terminal are respectively connected to two different access network devices, such as two different RANs, and can transmit data through the two access network devices.

[0151] For example, two different access network devices are described using RAN1 and RAN2 as examples. For example, RAN1 and RAN2 are both 3GPP access types, and RAN1 and RAN2 have the same or different RAT types. For example, the RAT type can be E-UTRA, 5G NR, 5G NR (satellite), or 6G RAT. 5G NR (satellite) can be further divided into low earth orbit (LEO), medium earth orbit (MEO), and geostationary earth orbit (GEO).

[0152] For example, as shown in Figure 3, a dual-directional device includes two terminals (e.g., a first terminal UE1 and a second terminal UE2). UE1 is connected to RAN1, and UE2 is connected to RAN2. UE1 and UE2 can access the same PLMN or different PLMNs. The HPLMNs of UE1 and UE2 can be the same or different. Therefore, the dual-directional device connects to different RANs through the two terminals.

[0153] In the embodiment of the present application, the two terminals (for example, UE1 and UE2) included in the dual-directional device are taken as an example for illustration, and the two terminals can be two devices / apparatuses. Alternatively, the two UEs included in the dual-directional device can be two USIMs, for example, UE1 can be the first USIM and UE2 can be the second USIM. Alternatively, the dual-directional device is a terminal, and the terminal includes two USIMs, UE1 corresponds to the first USIM, and UE2 corresponds to the second USIM. Accordingly, in the embodiment of the present application, the dual-directional device can be replaced by a terminal, the UE is replaced by a USIM, UE1 is replaced by the first USIM, and UE2 is replaced by the second USIM. Alternatively, the dual-directional device is a terminal, and the terminal includes at least two protocol stacks (Stacks), UE1 is replaced by protocol stack 1, and UE2 is replaced by protocol stack 2.

[0154] A dual-directional device is a device with dual-directional capabilities. Dual-directional means that the service data of the device can be directed to be transmitted through UE1 or UE2, or switched from being transmitted through UE1 to being transmitted through UE2.

[0155] In each of the following embodiments, the first network element may store network selection information of the first terminal and the second terminal. For example, the first network element may be a SOR AF or other network element, which is not limited in this application. The second network element may store the association between the first terminal and the second terminal. For example, the second network element stores the association between the identifier of the first terminal (for example, the identifier of the first terminal is a user subscription permanent identifier (SUPI) #1) and the identifier of the second terminal (for example, the identifier of the second terminal is SUPI #2). For example, in the process of the operator opening an account for the first terminal and the second terminal, the association between the two terminals exists, so the second network element may store the association between SUPI #1 and SUPI #2. Alternatively, the second network element may store that the first terminal and the second terminal allow dual-direction or support dual-direction. For another example, the first terminal and the second terminal are respectively associated with the user identifier, and then the first terminal is associated with the second terminal. For another example, the first terminal and the second terminal are respectively associated with the dual-direction device identifier, and then the first terminal is associated with the second terminal. Exemplarily, the second network element is used for data management or contract data management of the first terminal and the second terminal. For example, the second network element may be a UDM or other network element, which is not limited in this application. The third network element may be responsible for access management and / or mobility management of the first terminal. For example, the third network element may be AMF1 or other network element, which is not limited in this application. The third network element may store the identifier of the first terminal, for example, SUPI#1. The fourth network element may be responsible for access management and / or mobility management of the second terminal. For example, the fourth network element may be AMF2 or other network element, which is not limited in this application. The fourth network element may store the identifier of the second terminal, for example, SUPI#2. The fifth network element may be used to determine the authorized RFSP of the terminal or for access policy management of the second terminal. For example, the fifth network element may be a PCF or other network element, which is not limited in this application.

[0156] For ease of description, in the following embodiments, the first terminal accesses RAN1, and the second terminal accesses RAN2. The first network element is a SOR AF. Furthermore, the SOR AF can also be replaced by a communication device with SOR AF functionality, or a chip, unit, or module within a communication device with SOR AF functionality. The second network element is an UDM. Furthermore, the UDM can also be replaced by a communication device with UDM functionality, or a chip, unit, or module within a communication device with UDM functionality. The third network element is AMF1. Furthermore, AMF1 can also be replaced by a communication device with AMF1 functionality, or a chip, unit, or module within a communication device with AMF1 functionality. The fourth network element is AMF2. Furthermore, AMF2 can also be replaced by a communication device with AMF2 functionality, or a chip, unit, or module within a communication device with AMF2 functionality. The fifth network element is a PCF. Furthermore, the PCF can also be replaced by a communication device with PCF functionality, or a chip, unit, or module within a communication device with PCF functionality. Based on the above scenarios, how two associated terminals connected to different access network devices perform network selection is a question of concern. In order to solve this problem, the embodiments of the present application provide several possible communication methods to enable two different terminals to back up each other.

[0157] Example 1:

[0158] As shown in FIG4 , the present application provides a communication method, which includes:

[0159] Step 400: The UDM sends a first request message to the SOR AF. Correspondingly, the SOR AF receives the first request message from the UDM.

[0160] The first request message is used to request network selection information of the first terminal, and the first request message includes an identifier of the first terminal and first indication information, and the first indication information is used to indicate that the first terminal is associated with the second terminal. The identifier of the first terminal may be the SUPI of the first terminal.

[0161] The first indication information is used to indicate that the first terminal is associated with the second terminal. Alternatively, the first indication information may be used to indicate that the first terminal and the second terminal allow or support dual-steering, or the first indication information may be used to indicate that the first terminal and the second terminal are on the same device. For example, the first indication information may be dual-steering allowed (DualSteer authorized or DualSteer allowed).

[0162] Optionally, the first request message is used to request network selection information of the first terminal. Alternatively, the first request message is used to request updating of the network selection list of the first terminal, or the first request message is used to request the network selection list of the first terminal.

[0163] Optionally, the UDM sends the first request message to the SOR AF only under the condition that the first terminal and the second terminal allow or support bidirectional communication.

[0164] Optionally, the UDM sends the first request message to the SOR AF only under the condition that the first terminal is associated with the second terminal.

[0165] Exemplarily, the first indication information may include an identifier of the second terminal, such as a SUPI of the second terminal. Accordingly, the first request message includes the identifier of the first terminal and the identifier of the second terminal.

[0166] Exemplarily, the first request message is a SOR get request (SOR get request).

[0167] In a possible application scenario, the second terminal registers with the network first, and the first terminal registers with the network later. In the first terminal registration process, the UDM sends a first request message to the SOR AF.

[0168] In another possible application scenario, the first terminal and the second terminal have both connected to their respective networks. The first PLMN provides services for the first terminal, and the second PLMN provides services for the second terminal. When the first PLMN and the second PLMN are the same, the UDM sends a first request message to the SOR AF. The first PLMN and the second PLMN are the same, that is, the PLMN selected by the second terminal is the same as the PLMN selected by the first terminal, or the PLMN providing services to the second terminal is the same as the PLMN providing services to the first terminal, or the network accessed by the second terminal is the same as the network accessed by the first terminal. Here, only the example of the UDM requesting the SOR AF for the network selection information of the first terminal is used for explanation. In addition, it can also be replaced by the UDM requesting the SOR AF for the network selection information of the second terminal. The process is similar and will not be repeated here.

[0169] For example, after the first terminal accesses the first PLMN, AMF1 can send the identifier of the network currently accessed by the first terminal, that is, the identifier of the PLMN providing services for the first terminal, that is, the identifier of the first PLMN, to the UDM. After the second terminal accesses the second PLMN, AMF2 can send the identifier of the network currently accessed by the second terminal, that is, the identifier of the PLMN providing services for the second terminal, that is, the identifier of the second PLMN, to the UDM. The UDM can determine whether the first PLMN and the second PLMN are the same. If they are the same, the UDM sends a first request message to the SOR AF.

[0170] Step 410: The SOR AF determines the PLMN priority list of the first terminal according to the first indication information and the PLMN priority list of the second terminal.

[0171] Optionally, the PLMN priority list may be replaced by a network selection list.

[0172] Exemplarily, the SOR AF determines, based on the first indication information, that the first terminal is associated with the second terminal, and further determines the PLMN priority list of the first terminal based on the PLMN priority list of the second terminal.

[0173] In one example, if the first indication information includes the identifier of the second terminal, the SOR AF can query the PLMN priority list of the second terminal based on the identifier of the second terminal, and determine the PLMN priority list of the first terminal based on the PLMN priority list of the second terminal, so that the PLMN priority list of the first terminal is different from the PLMN priority list of the second terminal.

[0174] Exemplarily, that the PLMN priority list of the first terminal is different from the PLMN priority list of the second terminal may mean that the PLMN with the highest priority in the PLMN priority list of the first terminal is different from the PLMN with the highest priority in the PLMN priority list of the second terminal.

[0175] For example, in the PLMN priority list of the first terminal, the priority of PLMN1 is higher than the priority of PLMN2, and in the PLMN priority list of the second terminal, the priority of PLMN2 is higher than the priority of PLMN1. The types of PLMN1 and PLMN2 can be the same or different. For example, PLMN1 and PLMN2 can both be HPLMNs, or both PLMN1 and PLMN2 can be VPLMNs, or PLMN2 can be HPLMNs and PLMN1 can be VPLMNs.

[0176] For another example, in the PLMN priority list of the first terminal, the priority of the VPLMN is higher than the priority of the HPLMN, and in the PLMN priority list of the second terminal, the priority of the HPLMN is higher than the priority of the VPLMN.

[0177] In addition, the SOR AF may also update the PLMN priority list of the second terminal, or the SOR AF may not need to update the PLMN priority list of the second terminal.

[0178] Step 420: The SOR AF sends a first response message to the UDM. Correspondingly, the UDM receives the first response message from the SOR AF.

[0179] The first response message includes the PLMN priority list of the first terminal.

[0180] Optionally, if the SOR AF also updates the PLMN priority list of the second terminal, the SOR AF may also send the PLMN priority list of the second terminal to the UDM. The PLMN priority list of the second terminal may also be included in the first response message or sent separately, which is not limited in this application.

[0181] Furthermore, in step 430, the UDM sends the PLMN priority list of the first terminal to the AMF1. Correspondingly, the AMF1 receives the PLMN priority list of the first terminal from the UDM.

[0182] Optionally, if the SOR AF also sends the PLMN priority list of the second terminal to the UDM, the UDM may also send the PLMN priority list of the second terminal to AMF2. Furthermore, AMF2 sends the PLMN priority list of the second terminal to the second terminal via RAN2, and the second terminal may reselect a PLMN based on the PLMN priority list of the second terminal.

[0183] Step 440: AMF1 sends the PLMN priority list of the first terminal to the first terminal through RAN1. Correspondingly, the first terminal receives the PLMN priority list of the first terminal.

[0184] Step 450: The first terminal selects a PLMN according to the PLMN priority list of the first terminal.

[0185] For example, when the PLMN with the highest priority in the PLMN priority list of the first terminal is PLMN1 and the PLMN with the highest priority in the PLMN priority list of the second terminal is PLMN2, the first terminal will preferentially attempt to access PLMN1 according to the PLMN priority list of the first terminal, and the second terminal will preferentially attempt to access PLMN2 according to the PLMN priority list of the second terminal.

[0186] By adopting the above design, the first terminal and the second terminal can select different PLMNs as much as possible. The first terminal and the second terminal access different PLMNs, so that the first terminal and the second terminal can back up each other. For example, when the first terminal loses connection with the first PLMN it accesses, the data can be transferred to the second PLMN accessed by the second terminal for transmission.

[0187] Example 2:

[0188] As shown in FIG5 , the present application provides a communication method, which includes:

[0189] Step 500: The UDM sends a first request message to the SOR AF. The first request message is used to request network selection information of the first terminal. The first request message includes the identifier of the first terminal and first indication information. The first indication information is used to indicate that the first terminal is associated with the second terminal.

[0190] The first indication information may refer to the relevant description of the first indication information in the above step 400, which will not be repeated here.

[0191] Step 510: The UDM sends the identifier of the second PLMN to the SOR AF, where the second PLMN provides services for the second terminal.

[0192] It is understandable that the identifier of the second PLMN may also be carried in the first request message or sent separately, and this application does not limit this.

[0193] In one possible application scenario, the second terminal registers with the network first, and the first terminal registers with the network later. After the second terminal accesses the second PLMN, AMF2 can send the identifier of the network currently accessed by the second terminal, that is, the identifier of the PLMN providing service to the second terminal, that is, the identifier of the second PLMN, to the UDM. The UDM can send a first request message to the SOR AF, where the first request message includes the identifier of the first terminal, the first indication information, and the identifier of the second PLMN.

[0194] In another possible application scenario, the first terminal and the second terminal have both connected to their respective networks. The first PLMN provides services for the first terminal, and the second PLMN provides services for the second terminal. When the first PLMN and the second PLMN are the same, the UDM sends a first request message to the SOR AF, where the first request message includes the identifier of the first terminal, first indication information, and the identifier of the second PLMN. The first PLMN and the second PLMN are the same, that is, the PLMN selected by the second terminal is the same as the PLMN selected by the first terminal, or the PLMN serving the second terminal is the same as the PLMN serving the first terminal, or the network accessed by the second terminal is the same as the network accessed by the first terminal.

[0195] For example, after the first terminal accesses the first PLMN, AMF1 may send the identifier of the network currently accessed by the first terminal, that is, the identifier of the PLMN providing services to the first terminal, that is, the identifier of the first PLMN, to the UDM. After the second terminal accesses the second PLMN, AMF2 may send the identifier of the network currently accessed by the second terminal, that is, the identifier of the PLMN providing services to the second terminal, that is, the identifier of the second PLMN, to the UDM. The UDM may determine whether the first PLMN and the second PLMN are the same. If they are the same, the UDM sends a first request message to the SOR AF, wherein the first request message includes the identifier of the first terminal, the first indication information, and the identifier of the second PLMN.

[0196] Step 520: The SOR AF determines a PLMN priority list of the first terminal according to the first indication information and the identifier of the second PLMN, and the second PLMN provides service for the second terminal.

[0197] Optionally, the PLMN priority list may be replaced by a network selection list.

[0198] Exemplarily, the PLMN with the highest priority in the PLMN priority list of the first terminal is not the second PLMN, or the second PLMN has a low priority in the PLMN priority list of the first terminal.

[0199] Optionally, step 510 may be replaced by the UDM sending the type of the second PLMN (e.g., HPLMN, VPLMN, EPLMN) to the SOR AF, where the UDM determines the type of the second PLMN based on the identifier of the second PLMN. Accordingly, step 520 may be replaced by the SOR AF determining the PLMN priority list of the first terminal based on the first indication information and the type of the second PLMN. For example, if the type of the second PLMN is HPLMN, the PLMN with the highest priority in the PLMN priority list of the first terminal is not the HPLMN, or the HPLMN has a lower priority than other types of PLMNs (e.g., VPLMN) in the PLMN priority list of the first terminal.

[0200] In addition, the SOR AF may also update the PLMN priority list of the second terminal, or the SOR AF may not need to update the PLMN priority list of the second terminal.

[0201] Step 530: The SOR AF sends a first response message to the UDM. Correspondingly, the UDM receives the first response message from the SOR AF.

[0202] The first response message includes the PLMN priority list of the first terminal.

[0203] Optionally, if the SOR AF also updates the PLMN priority list of the second terminal, the SOR AF may also send the PLMN priority list of the second terminal to the UDM. The PLMN priority list of the second terminal may also be included in the first response message or sent separately, which is not limited in this application.

[0204] Furthermore, in step 540, the UDM sends the PLMN priority list of the first terminal to the AMF1. Correspondingly, the AMF1 receives the PLMN priority list of the first terminal from the UDM.

[0205] Optionally, if the SOR AF also sends the PLMN priority list of the second terminal to the UDM, the UDM may also send the PLMN priority list of the second terminal to AMF2. Furthermore, AMF2 sends the PLMN priority list of the second terminal to the second terminal via RAN2, and the second terminal may reselect a PLMN based on the PLMN priority list of the second terminal.

[0206] Step 550: AMF1 sends the PLMN priority list of the first terminal to the first terminal through RAN1. Correspondingly, the first terminal receives the PLMN priority list of the first terminal.

[0207] Step 560: The first terminal selects a PLMN according to the PLMN priority list of the first terminal.

[0208] For example, the PLMN providing service for the second terminal is PLMN2, the PLMN with the highest priority in the PLMN priority list of the first terminal is PLMN1, PLMN1 is different from PLMN2, and the first terminal preferentially attempts to access PLMN1 according to the PLMN priority list of the first terminal.

[0209] With the above design, the first terminal and the second terminal can select different PLMNs as much as possible. The first terminal and the second terminal access different PLMNs, so that the first terminal and the second terminal can back up each other.

[0210] Example 3:

[0211] As shown in FIG6 , the present application provides a communication method, which includes:

[0212] Step 600: The UDM obtains the PLMN priority list of the second terminal.

[0213] Exemplarily, the UDM may obtain the PLMN priority list of the second terminal from the SOR AF through an existing SOR procedure.

[0214] Step 610: The UDM sends the PLMN priority list of the second terminal to the first device via AMF2. The second terminal is located in the first device. Accordingly, the first device receives the PLMN priority list of the second terminal. Alternatively, the second terminal in the first device receives the PLMN priority list of the second terminal.

[0215] Exemplarily, UDM sends the PLMN priority list of the second terminal to AMF2, and AMF2 sends the PLMN priority list of the second terminal to the first device through RAN2.

[0216] Step 620: Optionally, when the first terminal is associated with the second terminal, the UDM sends third indication information to the first device via AMF2. Accordingly, the first device receives the third indication information. Alternatively, the second terminal in the first device receives the third indication information.

[0217] The third indication information indicates that the second terminal preferentially selects a PLMN, or that the second terminal is a master terminal in the first device, or that the second terminal selects a PLMN before other devices in the first device. Exemplarily, the UDM sends the third indication information to AMF2, and AMF2 sends the third indication information to the first device through RAN2.

[0218] Exemplarily, the association between the first terminal and the second terminal may be replaced by the first terminal and the second terminal allowing dual directionality, or the first device allowing dual directionality.

[0219] The third indication information may be sent in the same message as the PLMN priority list of the second terminal or sent separately in different messages, which is not limited in this application.

[0220] It can be understood that the first terminal and the second terminal are both located in the first device, or in other words, the first device includes the first terminal and the second terminal. In addition, the first device may also include other terminals, which is not limited in this application.

[0221] Step 630: The first device determines the second PLMN according to the PLMN priority list of the second terminal and the third indication information.

[0222] The second PLMN is a PLMN selected by the second terminal, or it can be understood that the second PLMN provides services for the second terminal.

[0223] Exemplarily, the second terminal in the first device determines the second PLMN according to the PLMN priority list of the second terminal and the third indication information. For example, when the first device receives the third indication information, the first device determines the second PLMN according to the PLMN priority list of the second terminal.

[0224] Step 640: The UDM obtains the PLMN priority list of the first terminal.

[0225] Exemplarily, the UDM may obtain the PLMN priority list of the first terminal from the SOR AF through an existing SOR procedure.

[0226] Step 650: The UDM sends the first terminal's PLMN priority list to the first device via AMF1. Accordingly, the first device receives the first terminal's PLMN priority list. Alternatively, the first terminal in the first device receives the first terminal's PLMN priority list. Exemplarily, the UDM sends the first terminal's PLMN priority list to AMF1, which in turn sends the first terminal's PLMN priority list to the first device via RAN1.

[0227] Step 660: When the first terminal is associated with the second terminal, the UDM may also send a second indication message to the first device via AMF1. Accordingly, the first device receives the second indication message. Alternatively, the first terminal in the first device receives the second indication message.

[0228] Exemplarily, the UDM sends the second indication information to AMF1, and AMF1 sends the second indication information to the first device through RAN1.

[0229] Exemplarily, the association between the first terminal and the second terminal may be replaced by the first terminal and the second terminal allowing dual directionality, or the first device allowing dual directionality.

[0230] The second indication information instructs the first terminal to select a PLMN different from the PLMN selected by the second terminal. Alternatively, the second indication information instructs the first terminal to select a PLMN different from the PLMN serving the second terminal. Alternatively, the second indication information instructs the first terminal to avoid selecting the same PLMN as the second terminal. Alternatively, the second indication information instructs the first device to allow dual-directional operation.

[0231] The second indication information may be sent in the same message as the PLMN priority list of the first terminal or sent separately in different messages, which is not limited in this application.

[0232] Step 670: The first device determines the first PLMN from the PLMN priority list of the first terminal according to the second indication information and the identifier of the second PLMN.

[0233] The first PLMN is different from the second PLMN.

[0234] Exemplarily, the first terminal in the first device determines the first PLMN from the PLMN priority list of the first terminal according to the second indication information and the identifier of the second PLMN.

[0235] Exemplarily, the first device may learn the PLMN selected by the second terminal, ie, the second PLMN, and then select a PLMN other than the second PLMN when selecting a PLMN according to the PLMN priority list of the first terminal.

[0236] Optionally, the second indication information instructs the first terminal to select a PLMN of a different type from the PLMN type selected by the second terminal, or the first terminal to avoid selecting the same type of PLMN as the second terminal. For example, if the type of the second PLMN is HPLMN, the first device determines the first PLMN from the PLMN priority list of the first terminal, and the type of the first PLMN is different from the HPLMN, for example, the type of the first PLMN is VPLMN.

[0237] It should be noted that step 630 is executed before step 670, and steps 600 to 620 need to be executed before executing step 630, and steps 640 to 660 need to be executed before executing step 670. However, there can be multiple combinations of the execution order of the above steps. For example, steps 600 to 620 can be before steps 640 to 660, or steps 600 to 620 can also be after steps 640 to 660; or, after obtaining the PLMN priority list of the second terminal (ie, step 600), and before sending the PLMN priority list of the second terminal to the first device through AMF2 (ie, step 610), the UDM can obtain the PLMN priority list of the first terminal (ie, step 640). The above examples are not intended to be limiting of this application.

[0238] In addition, in one possible design, the first device may further receive fourth indication information, where the fourth indication information indicates whether the first PLMN supports dual-directional capability. For example, the first device may further receive the fourth indication information from AMF1.

[0239] When the fourth indication information indicates that the first PLMN does not support dual-directional capability, the first device may further determine a third PLMN from the PLMN priority list of the first terminal, where the third PLMN is different from the second PLMN and different from the first PLMN. Exemplarily, the first device may determine the third PLMN from the PLMN priority list of the first terminal based on the second indication information and the identifier of the second PLMN. For example, the first device selects a PLMN with a next priority according to the PLMN priority list of the first terminal, and the PLMN is neither the second PLMN nor the first PLMN.

[0240] Furthermore, the first device may store that the first PLMN does not support dual-directional capability, so that the first PLMN is avoided from being selected when a PLMN is subsequently selected. For example, when the fourth indication information indicates that the first PLMN supports dual-directional capability, the first device may store that the first PLMN supports dual-directional capability, so that the first PLMN may be preferentially selected when a PLMN is subsequently selected.

[0241] Similarly, the first device may also receive indication information indicating whether the second PLMN supports the dual-directional capability, which will not be described in detail here.

[0242] With the above design, by sending the second indication information and the third indication information to the first device, the first terminal and the second terminal can select different PLMNs. The first terminal and the second terminal access different PLMNs, so that the first terminal and the second terminal can back up each other.

[0243] Example 4:

[0244] As shown in FIG7 , the present application provides a communication method, which includes:

[0245] Step 700: When the first terminal is associated with the second terminal and the first PLMN is the same as the second PLMN, the UDM sends fifth indication information to the first terminal via AMF 1. Correspondingly, the first terminal receives the fifth indication information.

[0246] The first PLMN provides services for the first terminal, the second PLMN provides services for the second terminal, and the fifth indication information instructs the first terminal to reselect the PLMN and / or the type of the PLMN selected by the first terminal. Accordingly, the first terminal receives the fifth indication information.

[0247] For example, if the type of the second PLMN is HPLMN, the fifth indication information instructs the first terminal to select a VPLMN or a PLMN of the VPLMN type.

[0248] Exemplarily, the UDM sends the fifth indication information to the AMF1, and the AMF1 sends the fifth indication information to the first terminal through the RAN1.

[0249] Exemplarily, the association between the first terminal and the second terminal may be replaced by the first terminal and the second terminal allowing dual directionality, or the first device allowing dual directionality.

[0250] For example, after the first terminal accesses the first PLMN, AMF1 can send the identifier of the network currently accessed by the first terminal, that is, the identifier of the PLMN providing services for the first terminal, that is, the identifier of the first PLMN, to the UDM. After the second terminal accesses the second PLMN, AMF2 can send the identifier of the network currently accessed by the second terminal, that is, the identifier of the PLMN providing services for the second terminal, that is, the identifier of the second PLMN, to the UDM. The UDM can determine whether the first PLMN and the second PLMN are the same.

[0251] Exemplarily, the type of the PLMN is a visited PLMN (VPLMN) or an equivalent PLMN (EPLMN).

[0252] In this embodiment, when the first terminal is associated with the second terminal and the first PLMN is the same as the second PLMN, the UDM sends fifth indication information to the first terminal via AMF1. It is understood that, alternatively, when the first terminal is associated with the second terminal and the first PLMN is the same as the second PLMN, the UDM sends fifth indication information to the second terminal via AMF2. In this case, the fifth indication information instructs the second terminal to reselect a PLMN and / or the type of the PLMN selected by the second terminal.

[0253] It is understandable that the PLMN priority list of the first terminal can be sent in the same message as the fifth indication information or sent separately in different messages, and this application does not limit this.

[0254] Step 710: The first terminal determines a fourth PLMN in the PLMN priority list of the first terminal according to the fifth indication information.

[0255] The fourth PLMN is a PLMN other than the first PLMN in the PLMN priority list of the first terminal, that is, the fourth PLMN is different from the first PLMN.

[0256] In an example, if the fifth indication information instructs the first terminal to reselect a PLMN, the first terminal may select a PLMN with a next priority according to the PLMN priority list of the first terminal according to the fifth indication information, and the PLMN is not the first PLMN.

[0257] In another example, if the fifth indication information indicates the type of PLMN selected by the first terminal, the first terminal determines whether the PLMN of the next priority meets the type of PLMN indicated by the fifth indication information according to the PLMN priority list of the first terminal based on the fifth indication information. If so, the PLMN is selected; otherwise, the judgment is continued in the order of the PLMN priority list of the first terminal until the type of PLMN indicated by the fifth indication information is met. Alternatively, when the fifth indication information instructs the first terminal to select a VPLMN or a PLMN of the VPLMN type, the first terminal selects the PLMN of the VPLMN from the PLMN priority list of the first terminal according to the fifth indication information, or selects the PLMN from the PLMN priority list of the VPLMN.

[0258] With the above design, when the first PLMN and the second PLMN are the same, by triggering the first terminal to reselect the PLMN and / or instructing the first terminal to select the type of PLMN, the first terminal and the second terminal can select different PLMNs, and the first terminal and the second terminal can access different PLMNs, so that the first terminal and the second terminal can back up each other.

[0259] Example 5:

[0260] As shown in FIG8 , the present application provides a communication method, which includes:

[0261] Step 800: The UDM sends a second request message to the SOR AF. The second request message is used to request network selection information of the first terminal. The second request message includes the identifier of the first terminal and first indication information. The first indication information is used to indicate that the first terminal is associated with the second terminal. In response, the SOR AF receives the second request message from the UDM.

[0262] Optionally, the second request message is used to request network selection information of the first terminal. Alternatively, the second request message is used to request updating of the network selection list of the first terminal, or the second request message is used to request the network selection list of the first terminal.

[0263] The identifier of the first terminal may be the SUPI of the first terminal.

[0264] The first indication information is used to indicate that the first terminal is associated with the second terminal. Alternatively, the first indication information may be used to indicate that the first terminal and the second terminal allow or support dual-directional communication, or the first indication information may be used to indicate that the first terminal and the second terminal are on the same device. Exemplarily, the first indication information may include an identifier of the second terminal, such as the SUPI of the second terminal. Accordingly, the second request message includes the identifier of the first terminal and the identifier of the second terminal.

[0265] Optionally, the UDM sends the second request message to the SOR AF only under the condition that the first terminal and the second terminal allow or support bidirectional communication.

[0266] Optionally, the UDM sends the second request message to the SOR AF only under the condition that the first terminal is associated with the second terminal.

[0267] Exemplarily, the first request message is a SOR acquisition request.

[0268] Step 810: The SOR AF determines the access technology priority list of the first terminal according to the first indication information and the access technology priority list of the second terminal, wherein the access technology priority list of the first terminal is different from the access technology priority list of the second terminal.

[0269] Exemplarily, the access technologies in the access technology priority list of the first terminal and the access technologies in the access technology priority list of the second terminal are used to access the same public land mobile network.

[0270] For example, a first terminal can access PLMN1 using either access technology #1 or access technology #2, and a second terminal can access PLMN1 using either access technology #1 or access technology #2. The SOR AF can configure different terminals to prioritize access to PLMN1 using different access technologies. For example, for the first terminal, access technology #1 has a higher priority than access technology #2; for the second terminal, access technology #2 has a higher priority than access technology #1. The priority list for the first terminal can be shown in Table 2, and the priority list for the second terminal can be shown in Table 3.

[0271] Table 2

[0272] Table 3

[0273] In addition, the SOR AF may also update the access technology priority list of the second terminal, or the SOR AF may not need to update the access technology priority list of the second terminal.

[0274] Step 820: The SOR AF sends a second response message to the UDM, where the second response message includes the access technology priority list of the first terminal, where the access technology priority list of the first terminal is different from the access technology priority list of the second terminal.

[0275] Optionally, if the SOR AF also updates the access technology priority list of the second terminal, the SOR AF may also send the access technology priority list of the second terminal to the UDM. The access technology priority list of the second terminal may also be included in the second response message or sent separately, which is not limited in this application.

[0276] It can be understood that the above embodiment can be combined with the embodiment shown in Figure 4 or Figure 5, when the SOR AF can send the PLMN priority list of the first terminal and the access technology priority list of the first terminal to the UDM.

[0277] Furthermore, in step 830, the UDM sends the access technology priority list of the first terminal to the AMF1. Accordingly, the AMF1 receives the access technology priority list of the first terminal from the UDM.

[0278] Optionally, if the SOR AF also sends the access technology priority list of the second terminal to the UDM, the UDM may also send the access technology priority list of the second terminal to AMF2. Furthermore, AMF2 sends the access technology priority list of the second terminal to the second terminal through RAN2, and the second terminal may select a high-priority access technology according to the access technology priority list of the second terminal to access the selected PLMN.

[0279] Step 840: AMF1 sends the access technology priority list of the first terminal to the first terminal through RAN1. Correspondingly, the first terminal receives the access technology priority list of the first terminal.

[0280] Step 850: The first terminal selects a high-priority access technology according to the access technology priority list of the first terminal to access the selected PLMN.

[0281] For example, the access technology priority list for the first terminal is shown in Table 2. When the first terminal selects to access PLMN1 according to Table 2, the first terminal preferentially selects access technology #1 to access PLMN1. The access technology priority list for the second terminal is shown in Table 3. When the second terminal selects to access PLMN1 according to Table 3, the second terminal preferentially selects access technology #2 to access PLMN1.

[0282] By using the above method, the first terminal and the second terminal can access the network or the same PLMN through different access technologies as much as possible. The first terminal and the second terminal that access the network through different access technologies can back up each other. For example, when the first terminal cannot access the network through access technology #1, such as when the connection fails, the data can be transferred to the second terminal that accesses the network through access technology #2 for transmission.

[0283] Example 6:

[0284] As shown in FIG9 , the present application provides a communication method, the method comprising:

[0285] Step 900: When a first terminal is associated with a second terminal, the UDM determines a subscription RFSP index of the first terminal and a subscription RFSP index of the second terminal.

[0286] Exemplarily, the association between the first terminal and the second terminal may be replaced by the first terminal and the second terminal allowing dual directionality, or the first device allowing dual directionality.

[0287] The subscription RFSP index of the first terminal is different from the subscription RFSP index of the second terminal. For example, the subscription RFSP index of the first terminal is 1, and the subscription RFSP index of the second terminal is 2. The subscription RFSP index of the first terminal is 1, indicating that E-UTRAN takes precedence over 5G NR, and the subscription RFSP index of the second terminal is 2, indicating that 5G NR takes precedence over E-UTRAN.

[0288] Step 910: The UDM sends the subscribed RFSP index of the first terminal to AMF1.

[0289] Step 920: UDM sends the subscribed RFSP index of the second terminal to AMF2.

[0290] Step 930: AMF1 determines a first RFSP index according to the subscribed RFSP index of the first terminal.

[0291] Among them, the first RFSP index is the RFSP index in use, and the first RFSP index refers to the RFSP index determined by AMF1 for the first terminal, or it can be understood that the first RFSP index refers to the RFSP index determined by AMF1 to be used by RAN1.

[0292] Exemplarily, AMF1 may directly use the subscribed RFSP index of the first terminal as the first RFSP index.

[0293] Step 940: AMF1 sends the first RFSP index to RAN1. Correspondingly, RAN1 receives the first RFSP index from AMF1.

[0294] Step 950: RAN1 determines the RAT of the first terminal according to the first RFSP index.

[0295] For example, if the first RFSP index is the same as the subscription RFSP index of the first terminal, the subscription RFSP index of the first terminal is 1, wherein the subscription RFSP index of the first terminal is 1, indicating that E-UTRAN takes precedence over 5G NR, then RAN1 controls the first terminal to access E-UTRAN first.

[0296] Step 960: AMF2 determines a second RFSP index based on the contracted RFSP index of the second terminal. The second RFSP index is the RFSP index in use. The second RFSP index refers to the RFSP index determined by AMF2 for the second terminal, or is described as the RFSP index determined by AMF2 to be used by RAN2.

[0297] Step 970: AMF2 sends the second RFSP index to RAN2. Correspondingly, RAN2 receives the second RFSP index from AMF2.

[0298] Step 980: RAN2 determines the RAT of the second terminal according to the second RFSP index.

[0299] For example, if the second RFSP index is the same as the subscription RFSP index of the second terminal, the subscription RFSP index of the second terminal is 2, where the subscription RFSP index of the first terminal is 2, indicating that 5G NR takes precedence over E-UTRAN, then RAN2 controls the second terminal to access 5G NR first.

[0300] By adopting the above method, the first terminal and the second terminal can access the network or the same PLMN through different access technologies as much as possible, and the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0301] Example 7:

[0302] As shown in FIG10 , the present application provides a communication method, which includes:

[0303] Step 1000: AMF1 sends first information to UDM. Correspondingly, UDM receives the first information from AMF1.

[0304] Among them, the first information indicates a first RFSP index and / or a first access type, the first RFSP index is the RFSP index determined by AMF1 for the first terminal, and the first access type is the access type corresponding to the access network device accessed by the first terminal, or in other words, the first access type is the RAT type corresponding to the access network device (RAN1) accessed by the first terminal.

[0305] For example, after AMF1 determines the first RFSP index, AMF1 may send the first information to the UDM. Alternatively, after RAN1 determines that the access type corresponding to the access network device accessed by the first terminal is the first access type, RAN1 may send the first access type to AMF1, and then AMF1 may send the first access type to the UDM.

[0306] In one possible implementation, before AMF1 sends the first information to UDM, UDM may further send sixth indication information to AMF1, where the sixth indication information is used to request the first information, or the sixth indication information is used to request the RFSP index determined by AMF1 for the first terminal. AMF1 sends the first information to UDM, where the first information includes the first RFSP index.

[0307] Step 1010: When the first terminal is associated with the second terminal, the UDM determines the subscribed RFSP index of the second terminal according to the first information.

[0308] Exemplarily, the association between the first terminal and the second terminal may be replaced by the first terminal and the second terminal allowing dual directionality, or the first device allowing dual directionality.

[0309] Exemplarily, when determining the contracted RFSP index of the second terminal according to the first information, the UDM updates the initial contracted RFSP index of the second terminal according to the first information, and determines the contracted RFSP index of the second terminal.

[0310] In an example, if the first information includes a first RFSP index, the UDM determines the contracted RFSP index of the second terminal according to the first RFSP index, and the contracted RFSP index of the second terminal is different from the first RFSP index.

[0311] For example, the first RFSP index is 1, and the subscription RFSP index of the second terminal is 2, wherein the first RFSP index is 1, indicating that E-UTRAN takes precedence over 5G NR, and the subscription RFSP index of the second terminal is 2, indicating that 5G NR takes precedence over E-UTRAN.

[0312] In another example, if the first information includes the first access type, the UDM determines the subscribed RFSP index of the second terminal according to the first access type.

[0313] For example, if the first access type is E-UTRAN, the subscribed RFSP index of the second terminal may indicate that 5G NR access takes precedence over E-UTRAN.

[0314] Step 1020: The UDM sends the subscribed RFSP index of the second terminal to AMF2. Correspondingly, AMF2 receives the subscribed RFSP index of the second terminal from the UDM.

[0315] Exemplarily, during the registration process of the second terminal, AMF2 may obtain the contract information of the second terminal from the UDM, wherein the contract information of the second terminal includes the contract RFSP index of the second terminal.

[0316] Step 1030: AMF2 determines a second RFSP index according to the subscribed RFSP index of the second terminal.

[0317] Among them, the second RFSP index is the RFSP index in use, and the second RFSP index refers to the RFSP index determined by AMF2 for the second terminal, or is described as the RFSP index determined by AMF2 to be used by RAN2.

[0318] Exemplarily, AMF2 may directly use the subscribed RFSP index of the second terminal as the second RFSP index.

[0319] Step 1040: AMF2 sends the second RFSP index to RAN2. Correspondingly, RAN2 receives the second RFSP index from AMF2.

[0320] Step 1050: RAN2 determines the RAT of the second terminal according to the second RFSP index.

[0321] By adopting the above method, the first terminal and the second terminal can access the network or the same PLMN through different access technologies as much as possible, and the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0322] Example 8:

[0323] The present application provides a communication method, the method comprising:

[0324] Step 1100: AMF1 sends first information to UDM. Correspondingly, UDM receives the first information from AMF1.

[0325] Among them, the first information indicates the first RFSP index and / or the first access type. The first RFSP index is the RFSP index determined by AMF1 for the first terminal, the first access type is the access type corresponding to the access network device accessed by the first terminal, or the first access type is the RAT type corresponding to the access network device (RAN1) accessed by the first terminal.

[0326] Step 1100 may refer to step 1000, and the repeated parts will not be repeated.

[0327] Step 1110: When the first terminal is associated with the second terminal, the UDM sends the second information to the AMF2. Correspondingly, the AMF2 receives the second information from the UDM.

[0328] Exemplarily, the association between the first terminal and the second terminal may be replaced by the first terminal and the second terminal allowing dual directionality, or the first device allowing dual directionality.

[0329] Optionally, when the first terminal is associated with the second terminal, the UDM sends the second information to the AMF2. Alternatively, when the context of the second terminal stored in the UDM includes dual-directional permission (DualSteer authorized or DualSteer allowed), the UDM sends the second information to the AMF2.

[0330] Optionally, UDM may also send a first indication message to AMF2, where the first indication message is used to indicate that the first terminal is associated with the second terminal. The first indication message and the second message may be sent in the same message or separately in different messages, and this application does not limit this. The first indication message is used to indicate that the first terminal is associated with the second terminal, and it may also be replaced by the first indication message being used to indicate that the first terminal and the second terminal allow dual-direction or support dual-direction, or the first indication message being used to indicate that the first terminal and the second terminal are on the same device. For example, the first indication message may be DualSteer authorized or DualSteer allowed.

[0331] Exemplarily, the second information includes third information and / or the contracted RFSP index of the first terminal, wherein the third information is determined based on the first RFSP index and / or the first access type; or, the second information includes at least one of the first RFSP index, the first access type, or the contracted RFSP index of the first terminal.

[0332] The following further describes possible implementations of the second information:

[0333] Mode 1: The first information includes the first RFSP index, and the second information includes the first RFSP index and / or the subscribed RFSP index of the first terminal.

[0334] Mode 2: The first information includes the first access type, and the second information includes the first access type and / or the subscribed RFSP index of the first terminal.

[0335] Mode 3: The first information includes the first RFSP index and the first access type, and the second information includes one or more of the first RFSP index, the first access type, or the subscribed RFSP index of the first terminal.

[0336] Mode 4: the second information includes the third information.

[0337] The third information is determined according to the first RFSP index and / or the first access type.

[0338] For example, if the first information includes a first access type, the third information includes a fourth access type, and the fourth access type is different from the first access type, the fourth access type indicates that the UDM recommends that the AMF use the fourth access type first, or the fourth access type indicates that the UDM recommends that the fourth access type have a higher priority than other access types.

[0339] For example, if the first information includes a first RFSP index, the third information includes a fourth RFSP index, and the fourth RFSP index is different from the first RFSP index, the fourth RFSP index indicates that the UDM recommends that the AMF prioritize the fourth RFSP index, or the fourth RFSP index indicates that the UDM recommends the fourth RFSP index as the RFSP index determined by AMF2 for the second terminal.

[0340] Mode 5: The second information includes the third information and the subscribed RFSP index of the first terminal.

[0341] It is understandable that the above-mentioned methods 1 to 5 are merely examples and are not intended to limit the present application.

[0342] In addition, in a possible implementation, AMF2 may also send fourth information to UDM, where the fourth information indicates a second RFSP index and / or a second access type. The second RFSP index is the RFSP index determined by AMF2 for the second terminal, and the second access type is the access type corresponding to the access network device accessed by the second terminal, or the second access type is the RAT type corresponding to the access network device (RAN2) accessed by the second terminal. When the first terminal is associated with the second terminal, UDM sends the second information to AMF2. This can also be replaced by when the first terminal is associated with the second terminal, and the first RFSP is the same as the second RFSP index and / or the first access type is the same as the second access type, UDM sends the second information to AMF2.

[0343] In one possible implementation, if the first information includes a first RFSP index, the fourth information includes a second RFSP index, and the first terminal is associated with the second terminal, and the first RFSP index is the same as the second RFSP index, the UDM sends the second information to AMF2.

[0344] In another possible implementation, if the first information includes a first access type, the fourth information includes a second access type, and the first terminal is associated with the second terminal, and the first access type is the same as the second access type, the UDM sends the second information to AMF2.

[0345] In another possible implementation, if the first information includes a first access type and a first RFSP index, and the fourth information includes a second access type and a second RFSP index, when the first terminal is associated with the second terminal, and the first access type is the same as the second access type, and the first RFSP index is the same as the second RFSP index, the UDM sends the second information to AMF2.

[0346] In addition, if the first terminal is associated with the second terminal, and the first RFSP and the second RFSP index are the same and / or the first access type is the same as the second access type, UDM can send the seventh indication information to AMF2, wherein the seventh indication information is used to indicate that the first terminal is associated with the second terminal, and the first RFSP and the second RFSP index are the same and / or the first access type is the same as the second access type, that is, UDM may not need to send the second information to AMF2, but only notify AMF2 that the first terminal and the second terminal are associated, and the first RFSP and the second RFSP index are the same and / or the first access type is the same as the second access type, thereby triggering AMF2 to re-determine the RFSP index for the second terminal.

[0347] Step 1120: AMF2 determines a third RFSP index according to the subscribed RFSP index of the second terminal and the second information.

[0348] In combination with the different contents of the second information, AMF2 may determine the third RFSP index in the following manners, but not limited to:

[0349] Method A: If the second information includes the first RFSP index, corresponding to possible methods 1 and 3 of the above-mentioned second information, AMF2 can determine the third RFSP index based on the first RFSP index and the contracted RFSP index of the second terminal.

[0350] For example, the RAT priority order represented by the first RFSP index is (RAT#1, RAT#2, RAT#3), and the RAT priority order represented by the contracted RFSP index of the second terminal is (RAT#1, RAT#3, RAT#2). Then the RAT priority order represented by the third RFSP index is (RAT#3, RAT#1, RAT#2).

[0351] That is, AMF2 may consider that the highest priority RAT in the RAT priority order represented by the determined third RFSP index is not RAT#1, and may combine the priority order of other RATs in the RAT priority order represented by the contracted RFSP index of the second terminal. For example, in the RAT priority order represented by the third RFSP index, the priority of RAT#1 is higher than that of RAT#2, and remains unchanged.

[0352] For another example, the RAT priority order represented by the first RFSP index is (RAT#1, RAT#2, RAT#3), and the RAT priority order represented by the contracted RFSP index of the second terminal is (RAT#1, RAT#2, RAT#3). Then the RAT priority order represented by the third RFSP index is (RAT#2, RAT#1, RAT#3).

[0353] That is, AMF2 may consider that the highest priority RAT in the RAT priority order represented by the determined third RFSP index is not RAT#1, and may combine the priority order of other RATs in the RAT priority order represented by the contracted RFSP index of the second terminal. For example, in the RAT priority order represented by the third RFSP index, the priority of RAT#1 is higher than that of RAT#3, which remains unchanged.

[0354] Method B: If the second information includes the first access type, corresponding to possible methods 2 and 3 of the above-mentioned second information, AMF2 can determine the third RFSP index based on the first access type and the subscribed RFSP index of the second terminal.

[0355] For example, if the first access type is RAT#1 and the RAT priority order represented by the subscribed RFSP index of the second terminal is (RAT#1, RAT#3, RAT#2), then the RAT priority order represented by the third RFSP index is (RAT#3, RAT#2, RAT#1).

[0356] That is, AMF2 may consider that the highest priority RAT in the RAT priority order represented by the determined third RFSP index is not RAT#1, and may combine the priority orders of other RATs in the RAT priority order represented by the contracted RFSP index of the second terminal.

[0357] Method C: If the second information includes the third information, and the third information includes the fourth RFSP index, corresponding to possible methods 4 and 5 of the above-mentioned second information, AMF2 can determine the third RFSP index based on the fourth RFSP index and the contracted RFSP index of the second terminal.

[0358] Exemplarily, AMF2 may use the fourth RFSP index as the third RFSP index, or AMF2 may determine the third RFSP index in combination with the fourth RFSP index and the subscribed RFSP index of the second terminal.

[0359] For example, the RAT priority order represented by the first RFSP index is (RAT#1, RAT#2, RAT#3), the RAT priority order represented by the fourth RFSP index is (RAT#2, RAT#1, RAT#3), and the RAT priority order represented by the contracted RFSP index of the second terminal is (RAT#1, RAT#2, RAT#3). Then the RAT priority order represented by the third RFSP index can be (RAT#2, RAT#1, RAT#3).

[0360] Method D: If the second information includes the third information, and the third information includes the fourth access type, corresponding to the possible methods 4 and 5 of the above-mentioned second information, AMF2 can determine the third RFSP index based on the fourth access type and the contracted RFSP index of the second terminal.

[0361] For example, the first access type is RAT#1, the fourth access type is RAT#2, and the RAT priority order represented by the contracted RFSP index of the second terminal is (RAT#1, RAT#3, RAT#2). Then the RAT priority order represented by the third RFSP index is (RAT#2, RAT#1, RAT#1).

[0362] In one possible implementation, if AMF2 also receives the first indication information, when determining the third RFSP index based on the contracted RFSP index of the second terminal and the second information, AMF2 determines the third RFSP index based on the first indication information, the contracted RFSP index of the second terminal, and the second information. In other words, when AMF2 receives the first indication information, AMF2 determines the third RFSP index based on the contracted RFSP index of the second terminal and the second information.

[0363] Step 1130: AMF2 sends the third RFSP index to RAN2. Correspondingly, RAN2 receives the third RFSP index from AMF2.

[0364] Step 1140: RAN2 determines the RAT of the second terminal according to the third RFSP index.

[0365] By adopting the above method, the first terminal and the second terminal can access the network or the same PLMN through different access technologies as much as possible, and the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0366] Example 9:

[0367] The present application provides a communication method, the method comprising:

[0368] Step 1200: The PCF obtains the subscribed RFSP index and second information of the second terminal.

[0369] The PCF is responsible for access policy management of the second terminal.

[0370] The PCF obtains the subscribed RFSP index and the second information of the second terminal in the following two ways, but not limited to:

[0371] Possible implementation method a: PCF receives the subscribed RFSP index and second information of the second terminal from AMF2.

[0372] Possible implementation b: PCF receives the subscribed RFSP index of the second terminal from AMF2, and PCF receives the second information from UDM or UDR.

[0373] In one example, the PCF learns that the first terminal is associated with the second terminal, and requests the second information from the UDM / UDR.

[0374] In another example, the UDM / UDR learns that the first terminal is associated with the second terminal. When the PCF obtains the contract information of the second terminal from the UDM / UDR, the UDM / UDR sends the contract information of the second terminal to the PCF, where the contract information of the second terminal includes the second information.

[0375] In another example, the UDM / UDR learns that the first terminal is associated with the second terminal. When the PCF obtains the contract information of the second terminal from the UDM / UDR, if the PLMN providing services for the first terminal and the PLMN providing services for the second terminal are the same, the UDM / UDR sends the contract information of the second terminal to the PCF, where the contract information of the second terminal includes the second information.

[0376] For a detailed description of the second information, please refer to the above steps 1110 to 1111.

[0377] Step 1210: The PCF determines the authorized RFSP index of the second terminal according to the subscribed RFSP index of the second terminal and the second information.

[0378] The process of AMF2 determining the third RFSP index based on the subscribed RFSP index of the second terminal and the second information is similar to that in the above step 1120, and is not repeated here.

[0379] Exemplarily, the PCF may also receive a first indication message from the AMF2 or UDM, where the first indication message is used to indicate that the first terminal is associated with the second terminal, or to indicate that the first terminal and the second terminal allow dual-steering or support dual-steering. For example, the first indication message may be DualSteer authorized or DualSteer allowed. When determining the authorized RFSP index of the second terminal based on the contracted RFSP index of the second terminal and the second information, the PCF determines the authorized RFSP index of the second terminal based on the first indication message, the contracted RFSP index of the second terminal and the second information. In other words, when the PCF receives the first indication message, the PCF determines the authorized RFSP index of the second terminal based on the contracted RFSP index of the second terminal and the second information.

[0380] Step 1220: The PCF sends the authorized RFSP index of the second terminal to AMF2. Correspondingly, AMF2 receives the authorized RFSP index of the second terminal from the PCF.

[0381] Step 1230: AMF2 determines a fifth RFSP index according to the authorized RFSP index of the second terminal.

[0382] Among them, the fifth RFSP index is the RFSP index in use, and the fifth RFSP index refers to the RFSP index determined by AMF2 for the second terminal, or is described as the RFSP index determined by AMF2 to be used by RAN2.

[0383] Step 1240: AMF2 sends the fifth RFSP index to RAN2. Correspondingly, RAN2 receives the fifth RFSP index from AMF2.

[0384] Step 1250: RAN2 determines the RAT of the second terminal according to the fifth RFSP index.

[0385] By adopting the above method, the first terminal and the second terminal can access the network or the same PLMN through different access technologies as much as possible, and the first terminal and the second terminal that access the network through different access technologies can back up each other.

[0386] It is understandable that in order to implement the functions in the above embodiments, each device (for example, the first network element, the second network element, the third network element, the fourth network element, the fifth network element, the first terminal, the second terminal, the first device, etc.) includes a hardware structure and / or software module corresponding to the execution of each function. It should be easily appreciated by those skilled in the art that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in a hardware or computer software-driven hardware manner depends on the specific application scenario and design constraints of the technical solution.

[0387] Figures 13 and 14 are schematic diagrams of possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the various devices in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments.

[0388] As shown in FIG. 13 , the communication device 1300 includes a processing unit 1310 and a transceiver unit 1320 .

[0389] When the communication device 1300 is used to implement the function of the first network element (e.g., SOR AF) in the method embodiment shown in FIG. 4 or FIG. 5 :

[0390] a transceiver unit, configured to receive a first request message from a second network element, where the first request message is used to request network selection information of a first terminal, the first request message including an identifier of the first terminal and first indication information, where the first indication information is used to indicate that the first terminal is associated with the second terminal;

[0391] a processing unit, configured to determine a public land mobile network priority list of the first terminal based on the first indication information and the public land mobile network priority list of the second terminal, or determine the public land mobile network priority list of the first terminal based on the first indication information and an identifier of a second public land mobile network, the second public land mobile network providing service to the second terminal;

[0392] The transceiver unit is configured to send a first response message to the second network element, where the first response message includes the public land mobile network priority list of the first terminal.

[0393] In one possible design, the first indication information includes an identifier of the second terminal.

[0394] In one possible design, the transceiver unit is configured to receive the identifier of the second public land mobile network from the second network element before determining the public land mobile network priority list of the first terminal based on the first indication information and the identifier of the second public land mobile network.

[0395] In one possible design, the transceiver unit is used to send the public land mobile network priority list of the second terminal to the second network element.

[0396] In one possible design, the first terminal and the second terminal are in the same dual-directional device.

[0397] When the communication device 1300 is used to implement the function of the second network element (e.g., UDM) in the method embodiment shown in FIG. 4 or FIG. 5 :

[0398] A transceiver unit is used to send and receive information, and a processing unit is used to send a first request message to a first network element through the transceiver unit, where the first request message is used to request network selection information of the first terminal, and the first request message includes an identifier and first indication information of the first terminal, where the first indication information is used to indicate that the first terminal is associated with the second terminal; and receive a first response message from the first network element, where the first response message includes a public land mobile network priority list of the first terminal.

[0399] In one possible design, the first indication information includes an identifier of the second terminal.

[0400] In one possible design, the transceiver unit is configured to send an identifier of a second public land mobile network to the first network element, where the second public land mobile network provides services for the second terminal.

[0401] In one possible design, the transceiver unit is configured to receive a public land mobile network priority list of the second terminal from the first network element.

[0402] In one possible design, the transceiver unit is used to send the first request message to the first network element when the first public land mobile network is the same as the second public land mobile network; wherein the first public land mobile network provides services for the first terminal and the second public land mobile network provides services for the second terminal.

[0403] In one possible design, the first terminal and the second terminal are in the same dual-directional device.

[0404] When the communication device 1300 is used to implement the function of the second network element (e.g., UDM) in the method embodiment shown in FIG6 :

[0405] a transceiver unit for sending and receiving information, and a processing unit for sending a public land mobile network priority list of a first terminal to a third network element through the transceiver unit, wherein the third network element is responsible for mobility management or access management of the first terminal; and when the first terminal is associated with a second terminal, sending second indication information to the third network element, the second indication information being used to instruct the first terminal to select a public land mobile network different from the public land mobile network selected by the second terminal, the public land mobile network selected by the first terminal belonging to the public land mobile network priority list of the first terminal.

[0406] In one possible design, the transceiver unit is used to send a third indication message to a fourth network element, where the third indication message is used to instruct the second terminal to give priority to a public land mobile network, or the second terminal is the main terminal in the first device, the first terminal and the second terminal are in the first device, and the fourth network element is responsible for the mobility management or access management of the second terminal.

[0407] When the communication device 1300 is used to implement the function of the first device in the method embodiment shown in FIG6 , the first device includes: a first terminal and a second terminal:

[0408] a transceiver unit, configured to receive a public land mobile network priority list of the first terminal and second indication information, wherein the second indication information is used to instruct the first terminal to select a public land mobile network different from the public land mobile network selected by the second terminal;

[0409] a processing unit, configured to determine, based on the second indication information and an identifier of a second public land mobile network, a first public land mobile network from a public land mobile network priority list of the first terminal, where the second public land mobile network is a public land mobile network selected by the second terminal, or the second public land mobile network provides service for the second terminal, and the first public land mobile network is different from the second public land mobile network.

[0410] In one possible design, the transceiver unit is configured to receive fourth indication information, where the fourth indication information indicates whether the first public land mobile network supports dual-directional capability;

[0411] a processing unit, configured to, when the fourth indication information indicates that the first public land mobile network does not support dual-directional capability, determine a third public land mobile network from the public land mobile network priority list of the first terminal, the third public land mobile network being different from the second public land mobile network and different from the first public land mobile network.

[0412] In one possible design, the transceiver unit is configured to receive third indication information, the third indication information being used to instruct the second terminal to preferentially select a public land mobile network or to be the master terminal in the first device; and receive a public land mobile network priority list for the second terminal;

[0413] A processing unit is configured to select the second public land mobile network from the public land mobile network priority list of the second terminal according to the third indication information.

[0414] When the communication device 1300 is used to implement the function of the second network element (e.g., UDM) in the method embodiment shown in FIG7 :

[0415] a transceiver unit configured to send and receive information, and a processing unit configured to send, through the transceiver unit, fifth indication information to a third network element when the first terminal is associated with the second terminal and the first public land mobile network is the same as the second public land mobile network, wherein the first public land mobile network provides services for the first terminal, the second public land mobile network provides services for the second terminal, and the fifth indication information instructs the first terminal to reselect a public land mobile network and / or the type of the public land mobile network selected by the first terminal.

[0416] In one possible design, the type of the public land mobile network is a visited public land mobile network or an equivalent public land mobile network.

[0417] When the communication device 1300 is used to implement the function of the first terminal in the method embodiment shown in FIG7 :

[0418] a transceiver unit, configured to receive fifth indication information, wherein the fifth indication information instructs the first terminal to reselect a public land mobile network and / or the type of the public land mobile network selected by the first terminal;

[0419] The processing unit is configured to determine a fourth public land mobile network in the public land mobile network priority list of the first terminal according to the fifth indication information.

[0420] In one possible design, the type of the public land mobile network is a visited public land mobile network or an equivalent public land mobile network.

[0421] When the communication device 1300 is used to implement the function of the first network element (e.g., SOR AF) in the method embodiment shown in FIG8 :

[0422] a transceiver unit, configured to receive a second request message from a second network element, where the second request message is used to request network selection information of a first terminal, where the second request message includes an identifier of the first terminal and first indication information, where the first indication information is used to indicate that the first terminal is associated with the second terminal;

[0423] a processing unit, configured to determine the access technology priority list of the first terminal according to the first indication information and the access technology priority list of the second terminal;

[0424] A transceiver unit is used to send a second response message to the second network element, where the second response message includes the access technology priority list of the first terminal.

[0425] In one possible design, the first indication information includes an identifier of the second terminal.

[0426] In one possible design, the transceiver unit is used to send the access technology priority list of the second terminal to the second network element.

[0427] In one possible design, the first terminal and the second terminal are in the same dual-directional device.

[0428] In one possible design, the access technology in the access technology priority list of the first terminal and the access technology in the access technology priority list of the second terminal are used to access the same public land mobile network.

[0429] When the communication device 1300 is used to implement the function of the second network element (e.g., UDM) in the method embodiment shown in FIG8 :

[0430] A transceiver unit is used to send and receive information, and a processing unit is used to send a second request message to the first network element through the transceiver unit, where the second request message is used to request network selection information of the first terminal, and the second request message includes an identifier of the first terminal and first indication information, where the first indication information is used to indicate that the first terminal is associated with the second terminal; and receive a second response message from the first network element, where the second response message includes an access technology priority list of the first terminal.

[0431] In one possible design, the first indication information includes an identifier of the second terminal.

[0432] In one possible design, the transceiver unit is used to receive the access technology priority list of the second terminal from the first network element.

[0433] In one possible design, the first terminal and the second terminal are in the same dual-directional device.

[0434] In one possible design, the access technology in the access technology priority list of the first terminal and the access technology in the access technology priority list of the second terminal are used to access the same public land mobile network.

[0435] When the communication device 1300 is used to implement the function of the second network element (e.g., UDM) in the method embodiment shown in FIG13 :

[0436] a processing unit, configured to determine, when a first terminal is associated with a second terminal, a contracted radio access technology or a frequency selection priority index of the first terminal and a contracted radio access technology or a frequency selection priority index of the second terminal, wherein the contracted radio access technology or the frequency selection priority index of the first terminal and the contracted radio access technology or the frequency selection priority index of the second terminal are different;

[0437] A transceiver unit is used to send the contracted wireless access technology or frequency selection priority index of the first terminal to a third network element, and the third network element is responsible for the mobility management or access management of the first terminal; and to send the contracted wireless access technology or frequency selection priority index of the second terminal to a fourth network element, and the fourth network element is responsible for the mobility management or access management of the second terminal.

[0438] When the communication device 1300 is used to implement the function of the second network element (e.g., UDM) in the method embodiment shown in FIG10 :

[0439] a transceiver unit, configured to receive first information from a third network element, the first information indicating a first radio access technology or frequency selection priority index and / or a first access type, the first radio access technology or frequency selection priority index being a radio access technology or frequency selection priority index determined by the third network element for the first terminal, and the first access type being an access type corresponding to an access network device accessed by the first terminal; the third network element being responsible for mobility management or access management of the first terminal;

[0440] a processing unit, configured to determine, when the first terminal is associated with a second terminal, a subscribed radio access technology or a frequency selection priority index of the second terminal according to the first information;

[0441] The transceiver unit is configured to send the subscribed radio access technology or frequency selection priority index of the second terminal to a fourth network element, and the fourth network element is responsible for the mobility management or access management of the second terminal.

[0442] In one possible design, the processing unit is used to update the initial contracted wireless access technology or frequency selection priority index of the second terminal according to the first information when determining the contracted wireless access technology or frequency selection priority index of the second terminal according to the first information, and determine the contracted wireless access technology or frequency selection priority index of the second terminal.

[0443] In one possible design, the first information indicates a first wireless access technology or a frequency selection priority index; and sixth indication information is sent to the third network element, where the sixth indication information is used to request the first information.

[0444] When the communication device 1300 is used to implement the function of the second network element (e.g., UDM) in the method embodiment shown in FIG11 :

[0445] A transceiver unit is configured to send and receive information, and a processing unit is configured to receive first information from a third network element through the transceiver unit, where the first information indicates a first radio access technology or frequency selection priority index and / or a first access type, where the first radio access technology or frequency selection priority index is a radio access technology or frequency selection priority index determined by the third network element for the first terminal, and the first access type is an access type corresponding to an access network device accessed by the first terminal; the third network element is responsible for mobility management or access management of the first terminal; when the first terminal is associated with a second terminal, second information is sent to a fourth network element, where the second information includes third information and / or the contracted radio access technology or frequency selection priority index of the first terminal, where the third information is determined based on the first radio access technology or frequency selection priority index and / or the first access type; or, the second information includes at least one of the first radio access technology or frequency selection priority index, the first access type, or the contracted radio access technology or frequency selection priority index of the first terminal, and the fourth network element is responsible for mobility management or access management of the second terminal.

[0446] In one possible design, the transceiver unit is used to receive fourth information from the fourth network element, where the fourth information indicates a second wireless access technology or frequency selection priority index and / or a second access type, where the second wireless access technology or frequency selection priority index is the wireless access technology or frequency selection priority index determined by the fourth network element for the second terminal, and the second access type is the access type corresponding to the access network device accessed by the second terminal; when the first terminal is associated with the second terminal, and the first wireless access technology or frequency selection priority is the same as the second wireless access technology or frequency selection priority index and / or the first access type is the same as the second access type, the second information is sent to the fourth network element.

[0447] In one possible design, the transceiver unit is used to send the subscribed wireless access technology or frequency selection priority index of the second terminal to the fourth network element.

[0448] In one possible design, the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type. If the first information includes the first access type, the third information includes a fourth access type, and the fourth access type is different from the first access type; and / or, if the first information includes the first wireless access technology or frequency selection priority index, the third information includes a fourth wireless access technology or frequency selection priority index, and the fourth wireless access technology or frequency selection priority index is different from the first wireless access technology or frequency selection priority index.

[0449] In one possible design, the transceiver unit is used to send first indication information to the fourth network element, where the first indication information is used to indicate that the first terminal is associated with the second terminal.

[0450] When the communication device 1300 is used to implement the function of the fourth network element (for example, AMF2) in the method embodiment shown in FIG11 :

[0451] a transceiver unit, configured to receive second information from a second network element, the second information including third information and / or a contracted radio access technology or frequency selection priority index of the first terminal, wherein the third information is determined based on the first radio access technology or frequency selection priority index and / or the first access type, or the second information includes at least one of the first radio access technology or frequency selection priority index, the first access type, or the contracted radio access technology or frequency selection priority index of the first terminal; wherein the first radio access technology or frequency selection priority index is a radio access technology or frequency selection priority index determined by the third network element for the first terminal, the first access type is an access type corresponding to an access network device accessed by the first terminal, and the third network element is responsible for mobility management or access management of the first terminal;

[0452] a processing unit, configured to determine a third radio access technology or frequency selection priority index according to the subscribed radio access technology or frequency selection priority index of the second terminal and the second information;

[0453] A transceiver unit is configured to send the third radio access technology or frequency selection priority index to an access network device accessed by the second terminal.

[0454] In one possible design, the transceiver unit is used to receive first indication information from the second network element, where the first indication information is used to indicate that the first terminal is associated with the second terminal; and the processing unit is used to determine the third wireless access technology or frequency selection priority index based on the first indication information, the contracted wireless access technology or frequency selection priority index of the second terminal and the second information when determining the third wireless access technology or frequency selection priority index based on the second terminal's contracted wireless access technology or frequency selection priority index and the second information.

[0455] In one possible design, the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type, wherein the third information includes a fourth access type, which is different from the first access type; and / or the third information includes a fourth wireless access technology or frequency selection priority index, which is different from the first wireless access technology or frequency selection priority index.

[0456] In one possible design, the transceiver unit is used to receive the subscribed wireless access technology or frequency selection priority index of the second terminal from the second network element.

[0457] In one possible design, the transceiver unit is used to send fourth information to the second network element, where the fourth information indicates a second wireless access technology or frequency selection priority index and / or a second access type. The second wireless access technology or frequency selection priority index is the wireless access technology or frequency selection priority index determined by the fourth network element for the second terminal, and the second access type is the access type corresponding to the access network device accessed by the second terminal.

[0458] When the communication device 1300 is used to implement the function of the fifth network element (e.g., PCF) in the method embodiment shown in FIG12 :

[0459] a transceiver unit, configured to obtain a contracted wireless access technology or frequency selection priority index of a second terminal and second information, the second information including third information and / or the contracted wireless access technology or frequency selection priority index of the first terminal, wherein the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type, or the second information includes at least one of the first wireless access technology or frequency selection priority index, the first access type, or the contracted wireless access technology or frequency selection priority index of the first terminal; wherein the first wireless access technology or frequency selection priority index is a wireless access technology or frequency selection priority index determined by a third network element for the first terminal, the first access type is an access type corresponding to an access network device accessed by the first terminal, and the third network element is responsible for mobility management or access management of the first terminal;

[0460] a processing unit, configured to determine an authorized radio access technology or a frequency selection priority index of the second terminal according to the subscribed radio access technology or the frequency selection priority index of the second terminal and the second information;

[0461] The transceiver unit is configured to send the authorized radio access technology or frequency selection priority index of the second terminal to a fourth network element, and the fourth network element is responsible for the mobility management or access management of the second terminal.

[0462] In one possible design, the transceiver unit is configured to receive first indication information from the second network element, where the first indication information is used to indicate that the first terminal is associated with the second terminal;

[0463] A processing unit, configured to determine the authorized wireless access technology or frequency selection priority index of the second terminal according to the first indication information, the contracted wireless access technology or frequency selection priority index of the second terminal and the second information when determining the authorized wireless access technology or frequency selection priority index of the second terminal according to the contracted wireless access technology or frequency selection priority index of the second terminal and the second information.

[0464] In one possible design, the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type, wherein, if the first information includes the first access type, the third information includes a fourth access type, and the fourth access type is different from the first access type; and / or, if the first information includes the first wireless access technology or frequency selection priority index, the third information includes a fourth wireless access technology or frequency selection priority index, and the fourth wireless access technology or frequency selection priority index is different from the first wireless access technology or frequency selection priority index.

[0465] In one possible design, the transceiver unit is used to receive the contracted wireless access technology or frequency selection priority index and the second information of the second terminal from the fourth network element when obtaining the contracted wireless access technology or frequency selection priority index and the second information of the second terminal.

[0466] In one possible design, the transceiver unit is used to receive the contracted wireless access technology or frequency selection priority index of the second terminal from the fourth network element when obtaining the contracted wireless access technology or frequency selection priority index and second information of the second terminal; and receive the second information from the second network element, which is used for data management of the second terminal.

[0467] A more detailed description of the processing unit 1310 and the transceiver unit 1320 can be directly obtained by referring to the relevant description in the above method embodiment, and will not be repeated here.

[0468] As shown in Figure 14, communication device 1400 includes a processor 1410 and an interface circuit 1420. Processor 1410 and interface circuit 1420 are coupled to each other. It is understood that interface circuit 1420 can be a transceiver or an input / output interface. Optionally, communication device 1400 may also include a memory 1430 for storing instructions executed by processor 1410, input data required by processor 1410 to execute instructions, or data generated after processor 1410 executes instructions.

[0469] When the communication device 1400 is used to implement the methods shown in FIG. 4 to FIG. 12 , the processor 1410 is used to implement the functions of the processing unit 1310 , and the interface circuit 1420 is used to implement the functions of the transceiver unit 1320 .

[0470] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0471] In this application, another example of a device is provided, which includes at least one processor and at least one memory, the at least one processor and the at least one memory being coupled, the at least one memory being used to store instructions. When the instructions are executed by the at least one processor, the communication device executes the method in the above-mentioned embodiment. Taking the communication device including a processor and a memory as an example, as shown in Figure 14, the communication device 1400 includes a processor 1410 and a memory 1430. The processor 1410 and the memory 1430 are coupled, and the memory 1430 stores instructions. When the instructions stored in the memory 1430 are executed by the processor 1410, the communication device 1400 executes the methods executed by each device in the above-mentioned embodiment.

[0472] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in each of the above-mentioned devices. The processor and storage medium can also exist in each device as discrete components.

[0473] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0474] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

Claims

1. A communication method, characterized in that: Applied to a first network element, the method includes: receiving a first request message from a second network element, where the first request message is used to request network selection information of a first terminal, the first request message including an identifier of the first terminal and first indication information, where the first indication information is used to indicate that the first terminal is associated with the second terminal; determining a public land mobile network priority list of the first terminal according to the first indication information and the public land mobile network priority list of the second terminal, or determining the public land mobile network priority list of the first terminal according to the first indication information and an identifier of a second public land mobile network, the second public land mobile network providing service to the second terminal; A first response message is sent to the second network element, where the first response message includes the public land mobile network priority list of the first terminal.

2. The method according to claim 1, wherein Before determining the public land mobile network priority list of the first terminal according to the first indication information and the identifier of the second public land mobile network, the method further includes: An identification of the second public land mobile network is received from the second network element.

3. A communication method, characterized in that: Applied to a second network element, the method includes: Sending a first request message to a first network element, where the first request message is used to request network selection information of a first terminal, the first request message including an identifier of the first terminal and first indication information, where the first indication information is used to indicate that the first terminal is associated with a second terminal; A first response message is received from the first network element, where the first response message includes a public land mobile network priority list of the first terminal.

4. The method according to claim 3, wherein Also includes: An identifier of a second public land mobile network is sent to the first network element, where the second public land mobile network provides service for the second terminal.

5. The method according to claim 3 or 4, wherein: Sending a first request message to a first network element includes: When the first public land mobile network and the second public land mobile network are the same, sending the first request message to the first network element; The first public land mobile network provides services for the first terminal, and the second public land mobile network provides services for the second terminal.

6. A communication method, characterized in that: Applied to a second network element, the method includes: sending the public land mobile network priority list of the first terminal to a third network element, wherein the third network element is responsible for mobility management or access management of the first terminal; When the first terminal is associated with the second terminal, second indication information is sent to the third network element, where the second indication information is used to instruct the first terminal to select a public land mobile network different from the public land mobile network selected by the second terminal, and the public land mobile network selected by the first terminal belongs to the public land mobile network priority list of the first terminal.

7. The method according to claim 6, wherein Also includes: Send a third indication message to the fourth network element, where the third indication message is used to instruct the second terminal to give priority to the public land mobile network, or the second terminal is the main terminal in the first device, the first terminal and the second terminal are in the first device, and the fourth network element is responsible for the mobility management or access management of the second terminal.

8. A communication method, characterized in that: Applied to a first device, the first device including: a first terminal and a second terminal; the method including: receiving a public land mobile network priority list of the first terminal and second indication information, wherein the second indication information is used to instruct the first terminal to select a public land mobile network different from the public land mobile network selected by the second terminal; Determining a first public land mobile network from a public land mobile network priority list of the first terminal according to the second indication information and the identifier of the second public land mobile network, where the second public land mobile network is a public land mobile network selected by the second terminal, or the second public land mobile network provides services for the second terminal, and the first public land mobile network is different from the second public land mobile network.

9. The method according to claim 8, wherein Also includes: receiving fourth indication information, where the fourth indication information indicates whether the first public land mobile network supports dual-directional capability; When the fourth indication information indicates that the first public land mobile network does not support dual-directional capability, determine a third public land mobile network from the public land mobile network priority list of the first terminal, where the third public land mobile network is different from the second public land mobile network and different from the first public land mobile network.

10. The method according to claim 8 or 9, characterized in that Also includes: receiving third indication information, where the third indication information is used to instruct the second terminal to preferentially select a public land mobile network or to be the master terminal in the first device; receiving a public land mobile network priority list of the second terminal; The second public land mobile network is selected from the public land mobile network priority list of the second terminal according to the third indication information.

11. A communication method, characterized in that: Applied to a second network element, the method includes: When the first terminal is associated with the second terminal and the first public land mobile network is the same as the second public land mobile network, fifth indication information is sent to a third network element, wherein the first public land mobile network provides services for the first terminal, the second public land mobile network provides services for the second terminal, and the fifth indication information instructs the first terminal to reselect a public land mobile network and / or a type of the public land mobile network selected by the first terminal.

12. The method according to claim 11, wherein The type of the PLMN is a visited PLMN or an equivalent PLMN.

13. A communication method, characterized in that: Applied to a first terminal, the method includes: receiving fifth indication information, where the fifth indication information instructs the first terminal to reselect a public land mobile network and / or the type of the public land mobile network selected by the first terminal; A fourth public land mobile network is determined in the public land mobile network priority list of the first terminal according to the fifth indication information.

14. The method according to claim 13, wherein The type of the PLMN is a visited PLMN or an equivalent PLMN.

15. A communication method, characterized in that: Applied to the second network element, the method includes receiving first information from a third network element, where the first information indicates a first radio access technology or a frequency selection priority index and / or a first access type, where the first radio access technology or the frequency selection priority index is a radio access technology or a frequency selection priority index determined by the third network element for the first terminal, and the first access type is an access type corresponding to an access network device accessed by the first terminal; The third network element is responsible for mobility management or access management of the first terminal; When the first terminal is associated with the second terminal, second information is sent to the fourth network element, where the second information includes third information and / or the contracted wireless access technology or frequency selection priority index of the first terminal, wherein the third information is determined based on the first wireless access technology or frequency selection priority index and / or the first access type; or, the second information includes at least one of the first wireless access technology or frequency selection priority index, the first access type, or the contracted wireless access technology or frequency selection priority index of the first terminal, and the fourth network element is responsible for the mobility management or access management of the second terminal.

16. The method according to claim 15, wherein Also includes: receiving fourth information from the fourth network element, the fourth information indicating a second radio access technology or frequency selection priority index and / or a second access type, where the second radio access technology or frequency selection priority index is a radio access technology or frequency selection priority index determined by the fourth network element for the second terminal, and the second access type is an access type corresponding to an access network device accessed by the second terminal; When the first terminal is associated with the second terminal, sending second information to the fourth network element, the method further includes: When the first terminal is associated with the second terminal, and the first radio access technology or frequency selection priority is the same as the second radio access technology or frequency selection priority index and / or the first access type is the same as the second access type, the second information is sent to the fourth network element.

17. The method according to claim 15 or 16, wherein: Also includes: Send the subscribed radio access technology or frequency selection priority index of the second terminal to the fourth network element.

18. The method according to any one of claims 15 to 17, wherein: The third information is determined according to the first radio access technology or the frequency selection priority index and / or the first access type, and the method includes: If the first information includes the first access type, the third information includes a fourth access type, and the fourth access type is different from the first access type; And / or, if the first information includes the first wireless access technology or frequency selection priority index, the third information includes a fourth wireless access technology or frequency selection priority index, and the fourth wireless access technology or frequency selection priority index is different from the first wireless access technology or frequency selection priority index.

19. The method according to any one of claims 15 to 18, wherein: Also includes: Sending first indication information to the fourth network element, where the first indication information is used to indicate that the first terminal is associated with the second terminal.

20. A communication method, characterized in that: Applied to a fourth network element, the method includes: Receiving second information from a second network element, the second information including third information and / or a contracted radio access technology or frequency selection priority index of the first terminal, wherein the third information is determined based on the first radio access technology or frequency selection priority index and / or the first access type, or the second information including at least one of the first radio access technology or frequency selection priority index, the first access type, or the contracted radio access technology or frequency selection priority index of the first terminal; wherein the first radio access technology or frequency selection priority index is a radio access technology or frequency selection priority index determined by the third network element for the first terminal, the first access type is an access type corresponding to an access network device accessed by the first terminal, and the third network element is responsible for mobility management or access management of the first terminal; Determine a third radio access technology or frequency selection priority index according to the subscribed radio access technology or frequency selection priority index of the second terminal and the second information; Send the third radio access technology or frequency selection priority index to the access network device accessed by the second terminal.

21. The method according to claim 20, wherein The method further comprises: receiving first indication information from the second network element, where the first indication information is used to indicate that the first terminal is associated with the second terminal; Determining a third radio access technology or frequency selection priority index according to the subscribed radio access technology or frequency selection priority index of the second terminal and the second information includes: The third radio access technology or frequency selection priority index is determined according to the first indication information, the subscribed radio access technology or frequency selection priority index of the second terminal and the second information.

22. The method according to claim 20 or 21, wherein: The third information is determined according to the first radio access technology or the frequency selection priority index and / or the first access type, and the method includes: The third information includes a fourth access type, where the fourth access type is different from the first access type; And / or, the third information includes a fourth radio access technology or a frequency selection priority index, and the fourth radio access technology or the frequency selection priority index is different from the first radio access technology or the frequency selection priority index.

23. The method according to any one of claims 20 to 22, wherein: Also includes: Receive the subscribed radio access technology or frequency selection priority index of the second terminal from the second network element.

24. The method according to any one of claims 20 to 23, wherein: Also includes: Send fourth information to the second network element, where the fourth information indicates a second wireless access technology or frequency selection priority index and / or a second access type. The second wireless access technology or frequency selection priority index is a wireless access technology or frequency selection priority index determined by the fourth network element for the second terminal, and the second access type is an access type corresponding to the access network device accessed by the second terminal.

25. A communication device, characterized in that: The method comprises a unit or module for executing the method according to any one of claims 1 to 24.

26. A communication device, characterized in that: The communication device includes at least one processor; the at least one processor is configured to execute the method according to any one of claims 1 to 24.

27. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a program, and when the program is run on a device, the device is caused to perform the method according to any one of claims 1 to 24.

28. A computer program product, characterized in that The computer program product includes a program or instructions, and when the program or instructions are executed by a device, the device is caused to perform the method according to any one of claims 1 to 24.

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