Communication method and device

Abstract

The present application relates to a communication method and apparatus. A first terminal device sends a first message for requesting the establishment of a first PDU session for the first terminal device. The first message also includes an identifier of the second terminal device and an identifier of the second PDU session, which is used by the first network device to select the second network device or to establish an association relationship between the first PDU session and the second PDU session. The first terminal device receives a second message from the first network device, and the second message includes information for accepting the establishment of the first PDU session. For example, service data can be transferred between PDU sessions with an associated relationship, and the service data of the first PDU session can be transferred to the second PDU session, or the service data of the second PDU session can be transferred to the first PDU session, thereby reducing the service interruption time during the media transfer process, and even eliminating the need for service interruption during the media transfer process, thereby improving the transmission quality of the service and also improving the user experience.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on August 25, 2021, with application number 202110982180.8 and application name “A Method for Transferring Between Devices”, 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 electronic technology, users have an increasing number of electronic devices at the same time. For example, users may have mobile phones, tablet computers (PADs), smart TVs, personal computers (PCs), smart watches, and other electronic devices with communication capabilities. When users use multiple electronic devices, they may need to transfer media from one device to another.

[0005] For example, a user might watch a video on a website on their phone while on their way home. Upon returning home, they turn on their smart TV and log in to the same account to continue watching the video. This is also the process of transferring media from one device to another. Therefore, when the user continues watching the video on the smart TV, the smart TV needs to reconnect to the video's application server before it can begin playing the video. In other words, during this media transfer process, when the next device continues to receive media information, the next device needs to reconnect to the application server, resulting in a relatively long service interruption.

[0006] It can be seen that the current media transfer process will cause a long period of business interruption. Summary of the Invention

[0007] Embodiments of the present application provide a communication method and apparatus for reducing service interruption time during media transfer.

[0008] In a first aspect, a first communication method is provided, which can be executed by a terminal device, or by a larger device including the terminal device, or by a chip system or other functional module, which can realize the function of the terminal device, and the chip system or functional module is, for example, set in the terminal device. The terminal device is, for example, referred to as a first terminal device. The method includes: sending a first message, the first message is used to request the establishment of a first protocol data unit (PDU) session for the first terminal device, the first message also includes an identifier of a second terminal device and an identifier of a second PDU session, the second PDU session is a PDU session of the second terminal device, the identifier of the second terminal device and the identifier of the second PDU session are used by the first network device to select a second network device or to establish an association relationship between the first PDU session and the second PDU session; receiving a second message from the first network device, the second message including information for accepting the establishment of the first PDU session.

[0009] In an embodiment of the present application, an association relationship can be established between the first PDU session of the first terminal device and the second PDU session of the second terminal device. For example, the business data can be transferred between the PDU sessions with the association relationship, and the business data of the first PDU session can be transferred to the second PDU session, or the business data of the second PDU session can be transferred to the first PDU session. Regardless of how the transfer is performed, the first PDU session and the second PDU session are both established PDU sessions. When performing media transfer, there is no need to establish a session before transferring, but the transfer can be performed directly, thereby reducing the time of business interruption during the media transfer process, and even the business does not need to be interrupted during the media transfer process, thereby improving the transmission quality of the business and also improving the user experience.

[0010] In combination with the first aspect, in a first optional implementation of the first aspect, the first message includes a first parameter, and the first parameter is used to indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship. For example, the first message can implicitly indicate that an associated relationship is established between the first PDU session and the second PDU session by including the identifier of the second terminal device and the identifier of the second PDU session, or implicitly indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship. Alternatively, the first message may also include a first parameter, and the first parameter may explicitly indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship, so that the indication method is clearer.

[0011] In combination with the first aspect or the first optional implementation of the first aspect, in the second optional implementation of the first aspect, the second message further includes a second parameter, and the second parameter is used to indicate a manner in which the PDU session performs data processing, and the manner in which the data processing is performed includes transferring service data between the first PDU session and the second PDU session, or transmitting service data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship. The network can send the second parameter to the first terminal device, so that the first terminal device can clearly understand the processing method of the service data that can be supported by the first PDU session.

[0012] In combination with the first aspect or the first optional implementation of the first aspect or the second optional implementation of the first aspect, in the third optional implementation of the first aspect, the second message includes the QoS flow information configured by the second network device for the first terminal device for transmitting the first service. For example, the first terminal device can perform service data processing in the process of establishing the first PDU session, such as transferring service data from the second PDU session to the first PDU session, or transmitting service data on the first PDU session and the second PDU session. To transmit service data on the first PDU session, the second network device can configure the QoS flow information for the first terminal device for transmitting the first service, which can be sent to the first terminal device through the second message. In this way, the PDU session establishment process and the service data processing process can be completed synchronously, which can reduce the execution steps and improve the processing efficiency of service data.

[0013] In combination with the first aspect or the first optional implementation of the first aspect or the second optional implementation of the first aspect, in the fourth optional implementation of the first aspect, the method further includes: receiving a third message from the first network device, the third message including the QoS flow information configured by the second network device for the first terminal device to transmit the first service. For example, the first terminal device can perform service data processing after the establishment of the first PDU session is completed. Then, after the establishment of the first PDU session is completed, the second network device sends the QoS flow information for transmitting the first service to the first terminal device through the third message. The processing flow in this manner can be better compatible with existing processes such as PDU session establishment.

[0014] In combination with the first aspect or any one of the first optional implementation manners to the fourth optional implementation manners of the first aspect, in the fifth optional implementation manner of the first aspect, the method further includes: sending information about the first service to the second network device, the information about the first service including an identifier of the first service and / or packet information for describing a data flow of the first service. The first terminal device can request to perform processing of service data. For example, if the service data of the first service needs to be processed, the first terminal device can send information about the first service to the second network device, so that the second network device can perform processing of the service data of the first service.

[0015] In a second aspect, a second communication method is provided, which can be executed by a terminal device, or by a larger device including the terminal device, or by a chip system or other functional module, which can realize the functions of the terminal device, and the chip system or functional module is, for example, arranged in the terminal device. The terminal device is, for example, referred to as a second terminal device. The method includes: sending a sixth message to a first network device, the sixth message being used to request establishment of a second PDU session for the second terminal device, the sixth message including a first parameter, the first parameter being used to indicate that the second PDU session requested to be established by the second terminal device is a PDU session with an associated relationship and / or for selecting a second network device; and receiving an eighth message from the first network device, the eighth message including information for accepting the establishment of the second PDU session.

[0016] When establishing the second PDU session, the second terminal device can establish the second PDU session as a PDU session with an associated relationship, so that an associated relationship can be established between the first PDU session of the first terminal device and the second PDU session of the second terminal device. For example, the business data can be transferred between the PDU sessions with an associated relationship, and the business data of the first PDU session can be transferred to the second PDU session, or the business data of the second PDU session can be transferred to the first PDU session. Regardless of how the transfer is performed, the first PDU session and the second PDU session are both established PDU sessions. When performing media transfer, there is no need to establish a session first and then transfer. Instead, the transfer can be performed directly, thereby reducing the time of business interruption during the media transfer process, and even the business does not need to be interrupted during the media transfer process, thereby improving the transmission quality of the business and also improving the user experience.

[0017] In combination with the second aspect, in a first optional implementation of the second aspect, the eighth message also includes a second parameter, and the second parameter is used to indicate the way in which the PDU session performs data processing, and the way in which the data processing is performed includes transferring business data between the second PDU session and the PDU session of the other terminal device, or transmitting business data on the second PDU session and the PDU session of the other terminal device, and the PDU session of the other terminal device has an association relationship with the second PDU session, wherein the data processing can be performed between the PDU sessions with an association relationship. The network can send the second parameter to the second terminal device, so that the second terminal device can clearly understand the way in which the business data can be processed that the second PDU session can support. Particularly, since the first PDU session and the second PDU session have an association relationship, the second parameter sent by the network to the first terminal device and the second parameter sent to the second terminal device can be the same parameter.

[0018] In combination with the second aspect or the first optional implementation of the second aspect, in the second optional implementation of the second aspect, the method further includes: sending information about the first service to the second network device, the information about the first service including an identifier of the first service and / or packet information for describing a data flow of the first service. The first terminal device can request to perform processing of service data, and the second terminal device can also request to perform processing of service data. For example, if the service data of the first service needs to be processed, the second terminal device can send information about the first service to the second network device, so that the second network device can perform processing of the service data of the first service.

[0019] According to a third aspect, a third communication method is provided, which can be executed by a first network device, or by a larger device including the first network device, or by a chip system or other functional module, which can realize the function of the first network device, and the chip system or functional module is, for example, arranged in the first network device. The first network device is, for example, a core network device, such as an AMF, which can be referred to as a first AMF, or the first network device can also be other devices. The method includes: receiving a first message, the first message being used to request establishment of a first PDU session for a first terminal device, the first message also including an identifier of a second terminal device and an identifier of a second PDU session, the second PDU session being the PDU session of the second terminal device; selecting a second network device for the first PDU session based on the identifier of the second terminal device and the identifier of the second PDU session, the second network device being a network device serving the second PDU session.

[0020] In a fourth aspect, a fourth communication method is provided, which can be executed by a second network device, or by a larger device including the second network device, or by a chip system or other functional module, which can realize the function of the second network device, and the chip system or functional module is, for example, arranged in the second network device. The second network device is, for example, a core network device, such as an SMF, or the second network device may also be other devices. The method includes: receiving a fifth message from the first network device, the fifth message being used to request establishment of a first PDU session with an associated relationship for the first terminal device, the fifth message also including an identifier of the second terminal device and an identifier of the second PDU session, the second PDU session being the PDU session of the second terminal device, the fifth message being used to indicate establishment of an associated relationship between the first PDU session and the second PDU session; and sending a message to the first terminal device for accepting establishment of the first PDU session.

[0021] In a fifth aspect, a fifth communication method is provided, which can be executed by a fourth network device, or by a larger device including the fourth network device, or by a chip system or other functional module, which can realize the function of the fourth network device, and the chip system or functional module is, for example, set in the fourth network device. The fourth network device is, for example, a core network device, such as a UPF, or the fourth network device may also be other devices. The method includes: receiving a ninth message from a second network device, the ninth message being used to request the establishment of an N4 session and the allocation of a first tunnel, the first tunnel being associated with a first QoS flow, the N4 session being associated with a second PDU session, the first QoS flow being associated with the second PDU session, and the first QoS flow being used to transmit the data flow of the first service; and receiving a tenth message from the second network device, the tenth message being used to modify the N4 session and allocate a second tunnel. The second tunnel is associated with the first QoS flow, and the tenth message further indicates that data is transferred between different terminal devices through the first tunnel and the second tunnel, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, and the first QoS flow is also associated with the first PDU session; or, the second tunnel is associated with the second QoS flow, and the tenth message further indicates that data is transferred between different terminal devices through the first QoS flow and the second QoS flow, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, the first QoS flow is associated with the second PDU session, the second QoS flow is associated with the first PDU session, and the first QoS flow and the second QoS flow are used to transmit the data flow of the first service.

[0022] In a sixth aspect, a sixth communication method is provided, the method comprising: a first network device receives a first message, the first message being used to request establishment of a first PDU session for a first terminal device, the first message also including an identifier of a second terminal device and an identifier of a second PDU session, the second PDU session being a PDU session of the second terminal device; the first network device selects a second network device for the first PDU session based on the identifier of the second terminal device and the identifier of the second PDU session, and sends a fifth message to the second network device, the second network device being a network device serving the second PDU session, the fifth message being used to request establishment of the first PDU session with an associated relationship for the first terminal device, the fifth message also including an identifier of the second terminal device and an identifier of the second PDU session, the fifth message being used to indicate establishment of an association relationship between the first PDU session and the second PDU session; the second network device sends a ninth message to the fourth network device, the ninth message being used to request establishment of an N4 session and allocation of a first tunnel, the first tunnel being associated with a first QoS flow, the N4 session being associated with a second PDU session, the first QoS flow being associated with the second PDU session, the first QoS flow being used to transmit a data flow of a first service; the second network device sends a message to the first terminal device for accepting the establishment of the first PDU session.

[0023] In combination with the sixth aspect, in a first optional implementation manner of the sixth aspect, the second network device sends a tenth message to the fourth network device, and the tenth message is used to modify the N4 session and allocate a second tunnel. The second tunnel is associated with the first QoS flow, and the tenth message further indicates that data is transferred between different terminal devices through the first tunnel and the second tunnel, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, and the first QoS flow is also associated with the first PDU session; or, the second tunnel is associated with the second QoS flow, and the tenth message further indicates that data is transferred between different terminal devices through the first QoS flow and the second QoS flow, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, the first QoS flow is associated with the second PDU session, the second QoS flow is associated with the first PDU session, and the first QoS flow and the second QoS flow are used to transmit the data flow of the first service.

[0024] Regarding the technical effects brought about by any one of the third to sixth aspects, reference may be made to the introduction to the technical effects of the first and / or second aspects.

[0025] In a seventh aspect, a communication device is provided. The communication device may be the first terminal device described in any one of the first to sixth aspects. The communication device has the functions of the first terminal device. The communication device is, for example, the first terminal device, or a functional module in the first terminal device, such as a baseband device or a chip system. Alternatively, the communication device may be the second terminal device described in any one of the first to sixth aspects. The communication device has the functions of the second terminal device. The communication device is, for example, the second terminal device, or a functional module in the second terminal device, such as a baseband device or a chip system.

[0026] In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). The transceiver unit can implement a sending function and a receiving function. When the transceiver unit implements the sending function, it can be called a sending unit (sometimes also referred to as a sending module). When the transceiver unit implements the receiving function, it can be called a receiving unit (sometimes also referred to as a receiving module). The sending unit and the receiving unit can be the same functional module, which is called a transceiver unit, and the functional module can implement a sending function and a receiving function; or, the sending unit and the receiving unit can be different functional modules, and the transceiver unit is a general term for these functional modules.

[0027] In an optional implementation, the communication device also includes a storage unit, and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit, so as to enable the communication device to perform the functions of the first terminal device or the second terminal device described in any one of the first to sixth aspects above.

[0028] In an eighth aspect, a communication device is provided. The communication device may be the first network device described in any one of the first to sixth aspects. The communication device has the functions of the first network device. The communication device is, for example, the first network device, or a functional module in the first network device, such as a baseband device or a chip system. Alternatively, the communication device may be the second network device described in any one of the first to sixth aspects. The communication device has the functions of the second network device. The communication device is, for example, the second network device, or a functional module in the second network device, such as a baseband device or a chip system. Alternatively, the communication device may be the fourth network device described in any one of the first to sixth aspects. The communication device has the functions of the fourth network device. The communication device is, for example, the fourth network device, or a functional module in the fourth network device, such as a baseband device or a chip system.

[0029] In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). The transceiver unit can implement a sending function and a receiving function. When the transceiver unit implements the sending function, it can be called a sending unit (sometimes also referred to as a sending module). When the transceiver unit implements the receiving function, it can be called a receiving unit (sometimes also referred to as a receiving module). The sending unit and the receiving unit can be the same functional module, which is called a transceiver unit, and the functional module can implement a sending function and a receiving function; or, the sending unit and the receiving unit can be different functional modules, and the transceiver unit is a general term for these functional modules.

[0030] In an optional implementation, the communication device also includes a storage unit, and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit, enabling the communication device to perform the functions of the first network device, the second network device, or the fourth network device described in any one of the first to sixth aspects above.

[0031] In a ninth aspect, a computer-readable storage medium is provided, which is used to store computer programs or instructions. When the computer-readable storage medium is executed, the method performed by the first terminal device, the second terminal device, the first network device, the second network device, or the fourth network device in the above aspects is implemented.

[0032] In a tenth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the methods described in the above aspects to be implemented.

[0033] In the eleventh aspect, a device is provided, comprising one or more units for executing the method described in any embodiment of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of an application scenario of an embodiment of the present application;

[0035] Figure 2 A flowchart of the first communication method provided in an embodiment of the present application;

[0036] Figure 3 A flowchart of the second communication method provided in an embodiment of the present application;

[0037] Figure 4 A flowchart of a third communication method provided in an embodiment of the present application;

[0038] Figure 5A-5B Two schematic diagrams of QoS flows between UE and UPF in embodiments of the present application;

[0039] Figure 6 A flowchart of the fourth communication method provided in an embodiment of the present application;

[0040] Figure 7 A schematic diagram of a device provided in an embodiment of the present application;

[0041] Figure 8 A schematic diagram of another device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0043] Below, some terms or concepts in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

[0044] In the embodiment of the present application, the terminal device is a device with wireless transceiver function, which can be a fixed device, a mobile device, a handheld device (such as a mobile phone), a wearable device, an in-vehicle device, or a wireless device built into the above device (such as a communication module, a modem, or a chip system, etc.). The terminal device is used to connect people, objects, machines, etc., and can be widely used in various scenarios, such as but not limited to the following scenarios: cellular communication, device-to-device communication (device-to-device, D2D), vehicle to everything (vehicle to everything, V2X), machine-to-machine / machine-type communication (machine-to-machine / machine-type communications, M2M / MTC), Internet of Things (IoT), virtual reality (virtual reality, VR), augmented reality (augmented reality, AR), industrial control (industrial control), self-driving, remote medical, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, drone, robot and other scenarios. The terminal device may sometimes be referred to as user equipment (UE), terminal, access station, UE station, remote station, wireless communication device, or user device, etc. For ease of description, the terminal device is described using UE as an example in the embodiments of the present application.

[0045] The network devices in the embodiments of the present application include, for example, access network devices and / or core network devices. The access network device is a device with wireless transceiver functions, which is used to communicate with the terminal device. The access network device includes but is not limited to base stations (BTS, Node B, eNodeB / eNB, or gNodeB / gNB) in the above-mentioned communication system, transmission reception points (TRP), base stations subsequently evolved from the third generation partnership project (3GPP), access nodes in wireless fidelity (Wi-Fi) systems, wireless relay nodes, wireless backhaul nodes, etc. The base station can be: a macro base station, a micro base station, a pico base station, a small station, a relay station, etc. Multiple base stations can support the networks of the same access technology mentioned above, or they can support the networks of the different access technologies mentioned above. The base station can include one or more co-sited or non-co-sited transmission and reception points. The network device can also be a wireless controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario. The network device can also be a server or a wearable device, etc. For example, the network device in the vehicle to everything (V2X) technology can be a road side unit (RSU). The following describes the access network device by taking the base station as an example. The base station can communicate with the terminal device, or communicate with the terminal device through a relay station. The terminal device can communicate with multiple base stations in different access technologies. The core network device is used to implement functions such as mobility management, data processing, session management, policy and billing. The names of the devices that implement the core network functions in systems with different access technologies may be different, and the embodiments of the present application are not limited to this. Taking the 5G system as an example, the core network equipment includes: access and mobility management function (AMF), session management function (SMF), policy control function (PCF) or user plane function (UPF), etc.

[0046] In the embodiments of the present application, the communication device for implementing the network device function may be a network device, or may be a device capable of supporting the network device to implement the function, such as a chip system, which may be installed in the network device. In the technical solutions provided in the embodiments of the present application, the technical solutions provided in the embodiments of the present application are described by taking the network device as an example of the device for implementing the network device function being a network device.

[0047] In the embodiments of the present application, the number of nouns, unless otherwise specified, means "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "plural" means two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. For example, A / B means: A or B. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0048] The ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish between multiple objects, and are not used to limit the size, content, order, timing, priority or importance of multiple objects. For example, the first message and the second message can be the same message or different messages, and this name does not indicate the difference in size, content, priority or importance of the two messages. In addition, the numbering of the steps in the various embodiments introduced in this application is only for distinguishing different steps, and is not used to limit the order between the steps. For example, step S201 may occur before step S202, or may occur after S202, or may occur at the same time as S202.

[0049] Currently, with the development of electronic technology, users may own multiple electronic devices, such as mobile phones, PADs, smart TVs, etc. When using multiple electronic devices, users may need to transfer media from one device to another. For example, a user uses a mobile phone to watch a video on a website on the way home. After returning home, he turns on the smart TV and logs in to the same account using the smart TV to continue watching the video. This is the process of transferring media from one device to another. Then, when the user continues to watch the video on the smart TV, the smart TV needs to re-establish a connection with the application server of the video before it can start playing the video. That is to say, during this media transfer process, when the next device is used to continue to receive media information, the next device needs to re-establish a connection with the application server, which results in a relatively long service interruption time.

[0050] For example, a user uses a PAD to wirelessly cast a screen to a PC, causing the PC to display the content on the PAD. This is also the process of transferring media from one device to another. During the wireless casting process, the PAD cannot be exited midway, nor can it be moved to an area outside the wireless fidelity (Wi-Fi) coverage range. Otherwise, the wireless casting will be interrupted and the PC will not be able to continue to display the content on the PAD. In other words, in this media transfer process, the intermediate device (such as the PAD) needs to participate in the entire process, and the binding requirements for the devices are too strict.

[0051] In view of this, a technical solution of an embodiment of the present application is provided. In an embodiment of the present application, an association relationship can be established between the first PDU session of the first terminal device and the second PDU session of the second terminal device. For example, the PDU sessions with an associated relationship can perform a transfer of business data, and the business data of the first PDU session can be transferred to the second PDU session, or the business data of the second PDU session can be transferred to the first PDU session. Regardless of the transfer, the first PDU session and the second PDU session are both established PDU sessions. When performing media transfer, there is no need to establish a session before transferring, but the transfer can be performed directly, thereby reducing the time of business interruption during the media transfer process, and even the business does not need to be interrupted during the media transfer process, thereby improving the transmission quality of the business and improving the user experience. Alternatively, when performing media transfer, since the business data has been transferred to another PDU session, the previous PDU session (or the terminal device corresponding to the previous PDU session) no longer participates in the transmission of the business data, so the previous PDU session (or the terminal device corresponding to the previous PDU session) can exit, which also reduces the requirements for the degree of device binding and makes the application method more flexible.

[0052] The technical solutions provided in the embodiments of the present application can be applied to the fourth generation mobile communication technology (4G) system, such as the long term evolution (LTE) system, or can be applied to the fifth generation mobile communication technology (5G) system, such as the new radio (NR) system, or can also be applied to the next generation mobile communication system or other similar communication systems, without specific limitation. In addition, since the technical solutions provided in the embodiments of the present application involve media transfer between UEs, they can be applied to device-to-device (D2D) scenarios, such as NR-D2D scenarios, or can be applied to vehicle-to-everything (V2X) scenarios, such as NR-V2X scenarios. For example, it can be applied to the Internet of Vehicles, such as V2X, vehicle-to-vehicle (V2V), etc., or can be used in the fields of intelligent driving, assisted driving, or intelligent connected vehicles; for example, it can be applied to scenarios such as extended reality (XR) or screen projection.

[0053] Please refer to Figure 1 , taking the 5G system as an example, is a schematic diagram of an application scenario of an embodiment of the present application. Figure 1 Including UE, base station, AMF, SMF, UPF, unified data management (UDM) and data network (DN), Figure 1 The line in the figure indicates that two network elements can communicate with each other. Figure 1 "Ni (i = 1, 2, 3, 4, 6, 8, 11)" in the figure represents the interface between two network elements. For example, N1 represents the interface between UE and AMF, N2 represents the interface between the base station (or access network, or access network equipment) and AMF, N4 represents the interface between SMF and UPF, and so on.

[0054] The AMF is a core network entity of the fifth generation mobile communication technology (5G), which is used to manage the registration process, mobility process, and reachability of the UE.

[0055] SMF is a 5G core network entity used to manage the UE's PDU session, including the establishment, modification, and deletion of PDU sessions, as well as the establishment, modification, and deletion of Quality of Service (QoS) flows within PDU sessions.

[0056] The UDM is a 5G core network entity responsible for managing user subscription data. It functions similarly to the home subscriber server (HSS) in the fourth generation (4G) mobile communication technology. Figure 1 The UDM in can also be understood as a combination of UDM and HSS functions.

[0057] The UPF is a 5G core network entity responsible for sending and receiving user plane data. For example, after receiving data from a DN, the core network sends the data to the gNB via a tunnel between the UPF and a base station (e.g., a gNB). Alternatively, after receiving data from a gNB via a tunnel between the UPF and the gNB, the UPF sends the data to the DN.

[0058] The base station is, for example, a gNB, which is a 5G base station. It communicates with the UE through the air interface and sends and receives data with the UPF through a tunnel.

[0059] A DN is a data network, such as the internet or an Internet Protocol Multimedia Subsystem (IMS) network. An application server can be part of a DN network and provide corresponding applications (APPs), or in other words, corresponding service data.

[0060] The following describes the method provided by the embodiments of the present application in conjunction with the accompanying drawings. In the accompanying drawings corresponding to the various embodiments of the present application, all optional steps are represented by dotted lines. In the various embodiments of the present application, the first network device is, for example, an AMF, or it may be other devices; the second network device is, for example, an SMF, or it may be other devices; the third network device is, for example, an AMF, or it may be other devices; the fourth network device is, for example, a UPF, or it may be other devices. In the following introduction, the first network device is an AMF (for example, referred to as the first AMF), the second network device is an SMF, the third network device is an AMF (for example, referred to as the second AMF), and the fourth network device is a UPF as an example. In the various embodiments of the present application, a "session" is, for example, a "PDU session", or it may be other types of sessions. In the following introduction, a "PDU session" is taken as an example.

[0061] The methods provided in each embodiment of this application can be applied to Figure 1 For example, the first UE involved in the method provided in each embodiment of the present application is Figure 1 UE1 in the second UE is Figure 1In UE2, the first AMF is Figure 1 AMF1 in the second AMF is Figure 1 The AMF2 in the first access network device is Figure 1 The base station 1 in the second access network device is Figure 1 In base station 2, SMF is Figure 1 The SMF and UPF in Figure 1 UPF in.

[0062] This application embodiment provides a first communication method, see Figure 2 , which is a flowchart of the method.

[0063] S201. A first UE sends a first message, where the first message may request establishment of a PDU session for the first UE. To distinguish the PDU session from other PDU sessions, for example, the first PDU session is referred to as a first PDU session. The first message may be, for example, a non-access stratum (NAS) message, or may be other messages.

[0064] For example, the first UE sends a first message to the first AMF, and the first AMF receives the first message from the first UE. The first AMF is the AMF serving the first UE. Figure 2 Take this as an example. Alternatively, the first UE sends a message to the SMF, and the message sent by the UE to the SMF needs to be forwarded through the AMF, so the first AMF also receives the first message from the first UE. The SMF is the SMF serving the first UE.

[0065] The first message, for example, includes the identifier of the second UE and the identifier of the second PDU session. The second PDU session has been established, and the second PDU session is the PDU session of the second UE. Optionally, the first message also includes a session establishment request message, and the session establishment request message can request to establish a session. For example, the first message is a NAS message, and the NAS message may include an N1 SM container (container). The N1 SM container can be regarded as a PDU session establishment request (PDU session establishment request) message for requesting to establish a PDU session. For the first AMF, after receiving the first message, the N1SM container is not parsed, but the N1 SM container is sent to the SMF. Optionally, the first message includes the identifier of the second UE and the identifier of the second PDU session, which means that the N1 SM container includes the identifier of the second UE and the identifier of the second PDU session, then the SMF can obtain the identifier of the second UE and the identifier of the second PDU session, but the first AMF cannot obtain the identifier of the second UE and the identifier of the second PDU session. Alternatively, the first message including the identifier of the second UE and the identifier of the second PDU session means that the N1SM container does not include the identifier of the second UE and the identifier of the second PDU session, but the fields in the first message other than the N1 SM container carry the identifier of the second UE and the identifier of the second PDU session, then the first AMF can obtain the identifier of the second UE and the identifier of the second PDU session, but the SMF cannot obtain the identifier of the second UE and the identifier of the second PDU session through the N1 SM container, and subsequently in S204, the AMF can send the identifier of the second UE and the identifier of the second PDU session to the SMF. Alternatively, the first message including the identifier of the second UE and the identifier of the second PDU session means that the N1 SM container includes the identifier of the second UE and the identifier of the second PDU session, and the fields in the first message other than the N1 SM container also carry the identifier of the second UE and the identifier of the second PDU session, then the first AMF can obtain the identifier of the second UE and the identifier of the second PDU session, and the SMF can also obtain the identifier of the second UE and the identifier of the second PDU session.

[0066] The identifier of the second UE included in the first message is, for example, the first identifier of the second UE, and the first identifier of the second UE is, for example, the 5G-globally unique temporary UE identity (GUTI) or mobile subscriber international ISDN / PSTN number (MSISDN) of the second UE. The identifier of the second PDU session is, for example, the ID of the second PDU session.

[0067] For the first AMF, if it is determined that the first message includes the first identifier of the second UE and the identifier of the second PDU session, an SMF can be selected for the first UE based on the first identifier of the second UE and the identifier of the second PDU session, or an SMF can be selected for the first PDU session, and / or an association relationship can be established between the first PDU session and the second PDU session based on the first identifier of the second UE and the identifier of the second PDU session. For example, the first AMF can select an SMF that serves the second PDU session for the first PDU session based on the first identifier of the second UE and the identifier of the second PDU session, that is, the SMF that serves the first PDU session and the SMF that serves the second PDU session are the same SMF. Because the transfer of service data between PDU sessions requires initiating a PDU session modification process, and generally speaking, the PDU session modification process is initiated by the SMF. Therefore, if the PDU sessions with an associated relationship are served by the same SMF, the SMF can more conveniently initiate the PDU session modification process, simplifying the process of transferring service data between PDU sessions. Moreover, SMF can also assign IP addresses to PDU sessions. If the SMF serving the associated PDU sessions is the same, then optionally, the SMF can assign the same IP address to the associated PDU sessions, so that these PDU sessions can be associated through IP addresses.

[0068] For SMF, if it is determined that the first UE carries the identifier of the second UE (for SMF, the second identifier of the second UE may be obtained, which will be introduced later) and the identifier of the second PDU session when requesting to establish a PDU session, the SMF can establish an association relationship between the first PDU session and the second PDU session based on the identifier of the second UE and the identifier of the second PDU session.

[0069] Optionally, the first message also includes a first parameter, which may indicate that the first UE requests to establish a PDU session with an associated relationship, or indicates that the PDU session (for example, the first PDU session) requested to be established by the first UE is a PDU session with an associated relationship. For example, the first parameter may be the request type (request type) included in the first message. If the value of the requesttype is a multi-UE PDU request (multi-UE PDU request), it means that the first parameter indicates that the PDU session requested to be established by the first UE is a PDU session with an associated relationship. Alternatively, the first parameter may also be implemented through other existing parameters in the first message, or the first parameter may also be a newly defined parameter in the first message. Since the first message also includes the first identifier of the second UE and the identifier of the second PDU session, the first AMF and / or SMF can clearly state that the first UE is requesting to establish an associated relationship for the first PDU session and the second PDU session.

[0070] Optionally, the first message further includes an identifier of the first UE, for example, the first message includes a first identifier of the first UE. The first identifier of the first UE includes, for example, a 5G-GUTI or MSISDN of the first UE.

[0071] Alternatively, the first UE executes S201, for example, it is triggered by the first UE. For example, if the second UE determines that the service data needs to be transferred, the second UE may trigger the first UE, so that the first UE executes S201 to establish a first PDU session. That is, before S201, S202 may be optionally included: the second UE sends information about the first service to the first UE, and accordingly, the second UE receives information about the first service from the first UE. The first service is a service that needs to be transferred from the second UE to the target UE, and the target UE may include, for example, the first UE, or the first UE and the second UE. In other words, the first service is a service that needs to be transferred from the second PDU session to the target PDU session, and the target PDU session may include, for example, the first PDU session, or the first PDU session and the second PDU session. After the second UE receives the information about the first service, it can be clear that the first service needs to be transferred between PDU sessions. At this time, if the second UE has not yet established a PDU session for the first service, the second UE may execute S201 to establish a first PDU session to transmit the first service. In S202, in addition to sending information about the first service to the first UE, the second UE can also send the identifier of the second UE (for example, the first identifier of the second UE) and the identifier of the second PDU session to the first UE, so that the first UE can send the first identifier of the second UE and the identifier of the second PDU session through the first message.

[0072] The information of the first service includes, for example, an identifier of the first service, and / or packet information for describing the data flow of the first service. The identifier of the first service is, for example, the ID of the first service, and the packet information for describing the data flow of the first service includes, for example, one or more items of the IP header information, triplet information, or five-tuple information of the first service. The triplet information of the first service includes, for example, the target IP address, target port number, and transport layer protocol corresponding to the first service. The five-tuple information of the first service includes, for example, the source IP address, target IP address, source port number, target port number, and transport layer protocol of the first service. The transport layer protocol is, for example, the transmission control protocol (TCP) or the user datagram protocol (UDP).

[0073] Optionally, in S202, the second UE may also send connection parameters to the first UE, and correspondingly, the first UE receives the connection parameters from the second UE. For example, the second UE sends information about the first service and connection parameters to the first UE through one message, or the second UE may also send information about the first service and connection parameters to the first UE respectively through different messages. The connection parameters are, for example, parameters corresponding to the first service (or corresponding to the second PDU session) for connecting to the network, for example, the connection parameters include parameters such as network slice information and / or data network name (DNN) corresponding to the second PDU session.

[0074] Alternatively, the first UE may determine the connection parameters on its own. For example, the first UE may determine the connection parameters based on information about the first service, and the second UE does not need to send the connection parameters to the first UE. Alternatively, the network (e.g., the first network device and / or the second network device, etc.) may set the connection parameters of the first PDU session based on the second PDU session. In this case, the second UE does not need to send the connection parameters to the first UE, and the first UE does not need to send the connection parameters to the network.

[0075] The first message requests to establish a PDU session for the first UE, for example, it requests to create a new first PDU session, or it may be a request to rebuild the first PDU session. If it is to rebuild the first PDU session, it indicates that the first PDU session has been established before and is currently in the reconstruction process. Alternatively, the first message may also be used to request to modify the first PDU session, which also indicates that the first PDU session has been established before and is currently in the modification process. If the first PDU session has been established before, the first PDU session established before may be a PDU session with an associated relationship, or it may be a PDU session without an associated relationship, or an ordinary PDU session. The embodiment of the present application takes the first message request to create a new PDU session for the first UE as an example.

[0076] S203. The first AMF selects an SMF for the first PDU session based on the identifier of the second UE (e.g., the first identifier of the second UE) and the identifier of the second PDU session. The SMF is, for example, the SMF serving the second PDU session.

[0077] Optionally, after receiving the first message, the first AMF may obtain the contract information of the first UE to determine whether the first UE supports the establishment of a PDU session with an associated relationship based on the contract information of the first UE. For example, if the contract information of the first UE includes one or more of the contract information for the first UE to establish a PDU session with an associated relationship (or, the contract information for the first UE to establish a multi-UE PDUrequest), personal network contract information, or virtual group contract information, the first AMF determines that it can establish a PDU session with an associated relationship for the first UE. If the contract information of the first UE does not include the above items, the first AMF determines that the first UE does not support the establishment of a PDU session with an associated relationship, or the first AMF determines that it cannot establish a PDU session with an associated relationship for the first UE. At this time, the first AMF may send a rejection message to the first UE to refuse to establish a PDU session with an associated relationship for the first UE; or, the first AMF may modify the PDU session requested to be established by the first request to a PDU session without an associated relationship, for example, the first AMF modifies the value of the request type included in the first request to a non-multi-UE PDU request, for example, to an initial request.

[0078] In addition, if the first AMF determines that the second PDU session is a PDU session with an associated relationship, for example, the value of the request type of the second PDU session is multi-UE PDU request, the first AMF may execute S202 (or, the first AMF determines that the second PDU session is a PDU session with an associated relationship, and the first AMF determines that the first UE supports the establishment of a PDU session with an associated relationship, then the first AMF may execute S202). If the first AMF determines that the second PDU session is not a PDU session with an associated relationship, for example, the value of the request type of the second PDU session is not multi-UE PDU request, the first AMF may reject the first UE's request to establish a PDU session, that is, reject the first message, or the first AMF may modify the first message, for example, modify the value of the request type included in the first message to non-multi-UE PDU request, for example, to initial request.

[0079] For example, the AMF serving the first UE is the first AMF, and the AMF serving the second UE is the second AMF. If the first AMF and the second AMF are the same AMF, the first AMF can determine which SMF is serving the second PDU session. If the first AMF and the second AMF are different AMFs, the first AMF can send a fourth message to the second AMF, and the fourth message can request information about the SMF serving the second PDU session. After receiving the fourth message, the second AMF can send the identifier of the SMF serving the second PDU session to the first AMF, so that after receiving the identifier of the SMF, the first AMF can select the SMF for the first PDU session.

[0080] S204. The first AMF sends a fifth message to the SMF. Accordingly, the SMF receives the fifth message from the first AMF. The fifth message may request establishment of a first PDU session with an associated relationship for the first UE. Optionally, the fifth message includes the first parameter.

[0081] For example, the first AMF sends the fifth message to the SMF by calling the service provided by the SMF. For example, the service provided by the SMF is the session update session management context request (Nsmf_PDUSession_UpdateSMContext Request) service, where Nsmf represents the service provided by the SMF, and "N" can be understood as a network function. Each service involved in the following text can be understood in a similar way. In addition, the "SM" in this service stands for session management (SM). After the SMF receives the Nsmf_PDUSession_UpdateSMContext Request from the first AMF, it can also send a session update session management context response (Nsmf_PDUSession_UpdateSMContextResponse) to the first AMF.

[0082] Optionally, the fifth message includes the identifier of the second UE and the identifier of the second PDU session to indicate that an association relationship is established between the first PDU session and the second PDU session. The identifier of the second UE included in the fifth message is, for example, the second identifier of the second UE, and the second identifier of the second UE includes, for example, the user permanent identifier (SUPI) or the international mobile subscriber identity (IMSI) of the second UE. The identifier of the second UE received by the first AMF may be the first identifier of the second UE, and the first identifier of the second UE includes, for example, 5G-GUTI or MSISDN. The first AMF may map the 5G-GUTI or MSISDN of the second UE to SUPI, or to IMSI, and then send the obtained SUPI or IMSI to the SMF.

[0083] Optionally, the fifth message may further include an identifier of the first UE, for example, the identifier of the first UE included in the fifth message is the second identifier of the first UE. The second identifier of the first UE may be the SUPI or IMSI of the first UE. The first AMF maps the received 5G-GUTI or MSISDN of the first UE to the SUPI, or to the IMSI, and then sends the obtained SUPI or IMSI to the SMF.

[0084] S205. The SMF determines whether to establish a PDU session with an associated relationship for the first UE.

[0085] After receiving the fifth message, the SMF may accept the establishment of a PDU session with an associated relationship for the first UE, or may refuse to establish a PDU session with an associated relationship for the first UE. Optionally, after receiving the fifth message, the SMF may determine whether the first UE supports the establishment of a PDU session with an associated relationship. For example, the SMF determines whether the first UE supports the establishment of a PDU session with an associated relationship based on the subscription information of the first UE. The determination method may refer to the determination method of the first AMF in S203.

[0086] If the SMF determines that the first UE supports establishing a PDU session with an associated relationship, the SMF may establish a PDU session with an associated relationship for the first UE. For example, the SMF assigns a first IP address to the first PDU session. Optionally, the first IP address is the same as the second IP address, and the second IP address is the IP address of the second PDU session. By making the IP addresses of the two PDU sessions the same, the two PDU sessions can be associated. It can be understood that making the IP addresses of the two PDU sessions the same is a way to establish an associated relationship between the two PDU sessions. Alternatively, the SMF may not assign an IP address to the first PDU session that is the same as the IP address of the second PDU session, that is, the first IP address and the second IP address may be different. Even if the first IP address and the second IP address are different, network elements such as the SMF and the AMF can clearly understand that the first PDU session and the second PDU session have an associated relationship. Among them, if the first IP address and the second IP address are different, the association relationship between the first PDU session and the second PDU session can be achieved by the UPF performing the transport layer proxy function, which will be introduced in the embodiments below.

[0087] If the SMF determines that the first UE does not support the establishment of a PDU session with an associated relationship, or that the SMF determines that a PDU session with an associated relationship cannot be established for the first UE, the SMF refuses to establish a PDU session with an associated relationship for the first UE. In this case, for example, the SMF does not need to perform subsequent steps, but can send a rejection message to the first UE to refuse to establish a PDU session with an associated relationship for the first UE; or, the SMF can modify the PDU session requested to be established in the fifth message to a PDU session without an associated relationship, for example, the SMF modifies the value of the request type included in the fifth message to a non-multi-UE PDU request, for example, to an initial request.

[0088] S206. The SMF sends an eleventh message to the UPF. Accordingly, the UPF receives the eleventh message from the SMF. The eleventh message may request establishment of an N4 session and allocation of a fourth tunnel. The fourth tunnel is associated with a third QoS flow, which is used to transmit the data flow of the first service. The third QoS flow is associated with the first PDU session.

[0089] The eleventh message may be, for example, an N4 session modification request, or other messages. The fourth tunnel is used for data transmission and reception between the UPF and the access network device and is a core network tunnel (CN tunnel) corresponding to the first UE. The UPF allocates the fourth tunnel, for example, by allocating a UPF address and port number to the fourth tunnel. The fourth tunnel may be used by the access network device serving the first UE to send data for the first UE to the UPF.

[0090] It should be noted that for PDU sessions with an associated relationship (such as the first PDU session and the second PDU session), their corresponding N4 sessions are the same, that is, the UPF can establish tunnels with the access network devices of the UEs serving these PDU sessions based on the same N4 session. At this time, since the second PDU session has been established, the N4 session has also been established during the establishment of the second PDU session. Therefore, after receiving the eleventh message, the UPF does not need to establish the N4 session again, but can allocate the fourth tunnel based on the N4 session.

[0091] S207: The UPF sends a twelfth message to the SMF. Accordingly, the SMF receives the twelfth message from the UPF. For example, if the eleventh message is an N4 session modification request, the twelfth message is, for example, an N4 session modification response. That is, the twelfth message can be considered a response to the fifth message.

[0092] The twelfth message may include information such as the UPF address and port number allocated by the UPF to the fourth tunnel.

[0093] S208. The SMF sends information such as the UPF address and port number corresponding to the fourth tunnel to the first access network device. The corresponding access network device receives information such as the UPF address and port number corresponding to the fourth tunnel. For example, the SMF may send information such as the UPF address and port number corresponding to the fourth tunnel to the first AMF, and the first AMF then sends information such as the UPF address and port number corresponding to the fourth tunnel to the first access network device. In this case, the first access network device receives information such as the UPF address and port number corresponding to the fourth tunnel from the first AMF. The first access network device is the access network device serving the first UE.

[0094] S209. The SMF sends a message to the first UE for accepting the establishment of the first PDU session. Correspondingly, the first UE receives a message from the SMF for accepting the establishment of the first PDU session. The message includes, for example, a PDU session establishment accept, where PDU session establishment accept may be used to indicate acceptance of the establishment of the first PDU session.

[0095] It should be noted that when SMF sends a message to UE, it generally needs to be forwarded through AMF. Therefore, SMF can call the service provided by the first AMF and send the PDU session establishment accept to the first AMF. The service is, for example, the communication N1N2 information transmission (Namf_Communication_N1N2MessageTransfer) service. Among them, N1 and N2 are the names of interfaces, N1 refers to the interface between UE and AMF, and N2 refers to the interface between the access network (AN) and AMF. Namf_Communication_N1N2MessageTransfer means that SMF will call the service provided by AMF (for example, the first AMF) to send information to the UE and the access network (for example, the first access network device). After the first AMF receives the PDU session establishment accept, it sends a second message to the first UE. The second message may include the PDU session establishment accept. For example, the second message sent by the first AMF is an N2 message (N2message), but the N2 message is sent to the first access network device, and the N2 message includes the PDU session establishment accept, and the N2 message is, for example, an N2 PDU session request (N2 PDU session request). After the first access network device receives the N2 message, it sends the PDU session establishment accept to the UE through an RRC message (RRC message), and the RRC message is, for example, an access network dedicated resource establishment (AN specific resource setup). Among them, PDU session establishment accept can be included in a container, and the container is included in Namf_Communication_N1N2MessageTransfer, N2 PDU session request, and AN specific resource setup.

[0096] Optionally, the Namf_Communication_N1N2MessageTransfer sent by the SMF to the first AMF may further include first association indication information, and the first association indication information may indicate that the first PDU session is established as a PDU session with an associated relationship (for example, indicating that the first PDU session is established as a multi-UE PDU session). After receiving the first association indication information, the first AMF may store information that the first PDU session is a PDU session with an associated relationship (for example, information that the first PDU session is of a multi-UE PDU session type). In addition, the first AMF may also store association relationship information, and the association relationship information may, for example, indicate the association relationship between the first PDU session and the second PDU session.

[0097] Optionally, the SMF may also send a second parameter to the first UE, and the second parameter may indicate a manner in which the PDU session performs data processing, wherein the data processing can be performed between PDU sessions with an associated relationship. The manner in which the PDU session performs data processing includes, for example, transferring service data between the first PDU session and the second PDU session, or transmitting service data on the first PDU session and the second PDU session. For example, the second parameter may be expressed as a multi-UE rule, or the second parameter may be included in the multi-UE rule. The second parameter may indicate the transfer of service data between PDU sessions by switching, and the transmission of service data on multiple PDU sessions may be understood as the sharing of service data on multiple PDU sessions, and the second parameter may be indicated by duplication. The second parameter may be included in a message for accepting the establishment of the first PDU session, or may be sent through other messages. If the SMF creates the first PDU session as a PDU session without an associated relationship, the SMF may not need to send the second parameter to the first UE. The second parameter may be included in the message used to accept the establishment of the first PDU session. For example, the first AMF may send the second parameter to the first UE through the second message. Alternatively, the SMF may also send the second parameter through other messages. In this case, the first AMF may also send the second parameter to the first UE through other messages instead of the second message.

[0098] For the UE, if the second parameter is received from the SMF, it can be determined that the first PDU session is a PDU session with an association relationship, and if the second parameter is not received from the SMF, it can be determined that the first PDU session is a PDU session without an association relationship. Alternatively, if the SMF creates the first PDU session as a PDU session with an association relationship, then in addition to sending the second parameter to the first UE, the SMF may also send second association indication information to the first UE. The second association indication information may indicate that the first PDU session is a PDU session with an association relationship. The UE can determine that the first PDU session is a PDU session with an association relationship based on the second association indication information. If the SMF creates the first PDU session as a PDU session without an association relationship, then in addition to not sending the second parameter to the first UE, the SMF may not send the second association indication information to the first UE. If the first UE does not receive the second association indication information from the SMF, it can be determined that the first PDU session is a PDU session without an association relationship. Alternatively, if the SMF creates the first PDU session as a PDU session without an association relationship, the SMF may, in addition to not sending the second parameter to the first UE, also send second association indication information to the first UE. The second association indication information may indicate that the first PDU session is a PDU session without an association relationship. The UE may determine that the first PDU session is a PDU session without an association relationship based on the second association indication information. If the SMF creates the first PDU session as a PDU session with an association relationship, the SMF may, in addition to sending the second parameter to the first UE, not send the second association indication information to the first UE. If the first UE does not receive the second association indication information from the SMF, it can determine that the first PDU session is a PDU session with an association relationship.

[0099] Optionally, after the first UE determines that the first PDU session is established, it may also send a first indication message to the second UE. The first indication message may indicate that the first PDU session is established, and / or the first indication message is used to trigger the data processing process of the PDU session (that is, trigger the transfer or sharing of service data between associated PDU sessions). After the second UE receives the first indication message, it may trigger the data processing process of the PDU session.

[0100] As described above, the SMF accepts the establishment of a PDU session with an associated relationship for the first UE. If the SMF refuses to establish a PDU session for the first UE, S209 can be replaced by the SMF sending a message to the first UE for refusing to establish the first PDU session. Accordingly, the first UE receives a message from the SMF for refusing to establish the first PDU session. The message includes, for example, a PDU session establishment reject. PDU session establishment reject can be used to indicate a refusal to establish the first PDU session, or to indicate a refusal to establish a PDU session with an associated relationship, or to indicate a refusal to establish a PDU session.

[0101] S210: The first access network device sends information about the third tunnel to the SMF. Correspondingly, the SMF receives the information about the third tunnel from the first access network device.

[0102] The first access network device allocates tunnel information for data transmission and reception between the first access network device and the UPF for the N4 session. This tunnel is, for example, called a third tunnel. The third tunnel is an access network tunnel used by the UPF to send data of the first UE to the first access network device. Information about the third tunnel includes, for example, the address of the first access network device and an identifier of the third tunnel.

[0103] The first access network device may send information about the third tunnel to the first AMF, and the first AMF may then send the information about the third tunnel to the SMF. For example, the first access network device sends an N2 PDU session response (N2 PDU session response) to the first AMF, and the N2 PDU session response may include information about the third tunnel. The first AMF invokes a service provided by the SMF to send information about the third tunnel to the SMF, such as Nsmf_PDUSession_UpdateSMContext Request.

[0104] S211. The SMF sends information about the third tunnel to the UPF. Correspondingly, the UPF receives information about the third tunnel from the SMF.

[0105] For example, the SMF sends an N4 session modification message to the UPF to send information of the third tunnel to the UPF.

[0106] S212. The first AMF stores the association relationship information.

[0107] In S209, it is introduced that the Namf_Communication_N1N2MessageTransfer sent by the SMF to the first AMF may include first association indication information. The first AMF may store information that the first PDU session is a PDU session with an associated relationship according to the first association indication information (for example, information that the first PDU session is of a multi-UE PDUsession type). In addition, the first AMF may also store association relationship information, for example, indicating the association relationship between the first PDU session and the second PDU session.

[0108] Among them, S202, S205-S208, S210-S212 are all optional steps. In addition, the UE PDU session establishment process may also include other steps, which are not limited in the embodiment of the present application and will not be described in detail.

[0109] Through the solution provided by the embodiment of the present application, the first UE establishes a first PDU session, and an association relationship can be established between the first PDU session and the second PDU session. For example, the PDU sessions with an association relationship can perform service data transfer, and the service data of the first PDU session can be transferred to the second PDU session, or the service data of the second PDU session can be transferred to the first PDU session. Regardless of how the transfer is performed, the first PDU session and the second PDU session are both established PDU sessions. When performing media transfer, there is no need to establish a session first and then transfer. Instead, the transfer can be performed directly, thereby reducing the service interruption time during the media transfer process, and even the service does not need to be interrupted during the media transfer process, thereby improving the transmission quality of the service and also improving the user experience.

[0110] exist Figure 2 In the embodiment shown, it is mentioned that the second PDU session of the second UE has been established. The second communication method provided in the embodiment of the present application is described below, which is used to introduce the process of establishing the second PDU session. Figure 3 , which is a flowchart of the method.

[0111] S301. The second UE sends a sixth message to the second AMF. Correspondingly, the second AMF receives the sixth message from the second UE. The sixth message may request to establish a PDU session for the second UE, for example, the PDU session is referred to as a second PDU session. The second PDU session is Figure 2 The second PDU session mentioned in the illustrated embodiment is the same PDU session. The second AMF is the AMF serving the second UE. The second AMF and the first AMF can be the same AMF or different AMFs.

[0112] The sixth message may include a first parameter, which may indicate that the second UE requests to establish a PDU session with an associated relationship (or indicates that the PDU session (e.g., the second PDU session) requested to be established by the second UE is a PDU session with an associated relationship), and / or, the first parameter may be used for the first AMF to select the SMF. For the implementation form of the first parameter, please refer to Figure 2 The embodiment shown.

[0113] The sixth message is, for example, a NAS message. The sixth message also includes, for example, an N1 session management container (N1 SM container), which includes a PDU session establishment request. N1 refers to the interface between the UE and the AMF. The interaction between the SMF and the UE is transparently transmitted through the AMF. Therefore, the first UE can encapsulate the interaction information in the N1 SM container. The first AMF does not parse the N1 SM container, but instead sends the N1 SM container to the SMF.

[0114] Optionally, the conditions for the second UE to trigger the establishment of a PDU session with an associated relationship include, for example, that the second UE has established a UE group with other UEs, and the second UE may transfer or share services with other UEs in the UE group, then the second UE may trigger the establishment of a PDU session with an associated relationship, such as a second PDU session. For example, the services that the second UE can support include services that can be transferred or shared (such as media services, such as video services, audio services or image services, etc.), and the second UE believes that these services may be transferred or shared with other UEs in the UE group, then the second UE may trigger the establishment of a PDU session with an associated relationship.

[0115] Alternatively, the conditions for the second UE to trigger the establishment of a PDU session with an associated relationship include, for example, that certain services, such as online video services, may be transferred or shared between the second UE and other UEs. When the second UE establishes a PDU session for these services, it can trigger the establishment of a PDU session with an associated relationship, such as a second PDU session.

[0116] Alternatively, the conditions for the second UE to trigger the establishment of a PDU session with an associated relationship include, for example, the second UE determining through machine learning or other means that for certain services, there will be transfer or sharing between the second UE and other UEs, for example, within a certain time range and / or geographical range, the second UE and other UEs may transfer or share certain services. Then, when the second UE establishes a PDU session for these services, if the time range and / or geographical range is met, the second UE can trigger the establishment of a PDU session with an associated relationship, such as a second PDU session.

[0117] The above is just an example. The conditions for the second UE to trigger the establishment of a PDU session with an associated relationship may also include other conditions, which are not limited in the embodiments of the present application.

[0118] The sixth message requests to establish a PDU session for the second UE, for example, it requests to create a new second PDU session, or it may also be a request to rebuild the second PDU session. If it is to rebuild the second PDU session, it indicates that the second PDU session has been established before, and the current process is rebuilding. Alternatively, the sixth message may also be used to request to modify the second PDU session, which also indicates that the second PDU session has been established before, and the current process is modifying. If the second PDU session has been established before, the second PDU session established before may be a PDU session with an associated relationship, or it may be a PDU session without an associated relationship, or an ordinary PDU session. The embodiment of the present application takes the sixth message request to create a new PDU session for the second UE as an example.

[0119] S302: The second AMF selects an SMF for the second PDU session. The second AMF may select an SMF that supports PDU sessions with an associated relationship for the second PDU session, for example, the second AMF selects an SMF that supports multi-UE PDU for the second PDU session.

[0120] Optionally, after receiving the sixth message, the second AMF may obtain the contract information of the second UE to determine whether the second UE supports the establishment of a PDU session with an associated relationship based on the contract information of the second UE. For example, if the contract information of the second UE includes one or more of the contract information for the second UE to establish a PDU session with an associated relationship (or, the contract information for the second UE to establish a multi-UE PDUrequest), personal network contract information, or virtual group contract information, the second AMF determines that it can establish a PDU session with an associated relationship for the second UE, and the second AMF may execute S302. If the contract information of the second UE does not include the above items, the second AMF determines that the second UE does not support the establishment of a PDU session with an associated relationship, or the second AMF determines that it cannot establish a PDU session with an associated relationship for the second UE. At this time, the second AMF may send a rejection message to the second UE to refuse to establish a PDU session with an associated relationship for the second UE; or, the second AMF may modify the PDU session requested to be established by the fourth request to a PDU session without an associated relationship, for example, the second AMF modifies the value of the request type included in the fourth request to a non-multi-UE PDU request, for example, to an initial request.

[0121] For example, Figure 2 In the embodiment shown, the first AMF selects the SMF serving the second PDU session for the first PDU session, then the SMF in the embodiment of the present application and Figure 2 The SMF in the embodiment shown is the same SMF. Figure 2 In the embodiment shown, the first AMF does not select the SMF that serves the second PDU session for the first PDU session, but selects other SMFs. Then the SMF in the embodiment of the present application is Figure 2 The SMFs in the illustrated embodiment are different SMFs.

[0122] S303: The second AMF sends a seventh message to the SMF. Accordingly, the SMF receives the seventh message from the second AMF. The seventh message may request establishment of a second PDU session with an associated relationship for the second UE. Optionally, the seventh message includes the first parameter.

[0123] The seventh message may include an identifier of the second UE, for example, a second identifier of the second UE. The second identifier of the second UE may include a SUPI or IMSI of the second UE. The second AMF may map the received 5G-GUTI or MSISDN of the second UE to a SUPI, or to an IMSI, and then send the obtained SUPI or IMSI to the SMF.

[0124] For example, the second AMF may call the service provided by the SMF to send the seventh message to the SMF, for example, the service is the Nsmf_PDUSession_UpdateSMContext Request service. Optionally, after the SMF receives the Nsmf_PDUSession_UpdateSMContext Request (Nsmf_PDUSession_UpdateSMContext Request can be regarded as the seventh message) from the second AMF, it can send an smf_PDUSession_UpdateSMContext Response response to the second AMF.

[0125] S304. The SMF determines whether to establish a PDU session with an associated relationship for the second UE.

[0126] After receiving the seventh message, the SMF can determine whether the second UE supports the establishment of a PDU session with an associated relationship. For example, the SMF determines whether the second UE supports the establishment of a PDU session with an associated relationship based on the contract information of the second UE. The determination method can refer to the determination method of the second AMF in S302. If the SMF determines that the second UE supports the establishment of a PDU session with an associated relationship, the SMF can establish a PDU session with an associated relationship for the second UE. If the SMF determines that the second UE does not support the establishment of a PDU session with an associated relationship, or if the SMF determines that a PDU session with an associated relationship cannot be established for the second UE, the SMF refuses to establish a PDU session with an associated relationship for the second UE. If the SMF refuses to establish a PDU session with an associated relationship for the second UE, the SMF does not have to perform subsequent steps, but can send a rejection message to the second UE to refuse to establish a PDU session with an associated relationship for the second UE; or, the SMF can modify the PDU session requested to be established by the seventh message to a PDU session without an associated relationship, for example, the SMF modifies the value of the request type included in the seventh message to a non-multi-UE PDUrequest, for example, to an initial request.

[0127] S305: The SMF sends a ninth message to the UPF. Accordingly, the UPF receives the ninth message from the SMF. The ninth message may request establishment of an N4 session and allocation of a first tunnel. The first tunnel is associated with a first QoS flow, which is used to transmit data flows for the first service. The first QoS flow is associated with the second PDU session.

[0128] The ninth message may be, for example, an N4 session modification request, or other messages. The first tunnel is used for data transmission and reception between the UPF and the access network device and is a CN tunnel corresponding to the second UE. The UPF allocates the first tunnel, for example, by allocating a UPF address and port number to the first tunnel. The first tunnel can be used by the access network device serving the second UE to send data for the second UE to the UPF.

[0129] Optionally, the ninth message may also indicate the execution of a transport layer proxy function, that is, the data transmission and reception between the UE's application and the application server is handled by the UPF. After receiving the ninth message, the UPF may execute the transport layer proxy function. For example, when the transport layer protocol is TCP, the UPF may execute the TCP proxy function. For another example, when the transport layer protocol is UDP, the UPF may execute the UDP proxy function. For TCP proxy, the UPF needs to establish a TCP connection with the application server of the second UE. The UPF executes the transport layer proxy function for the second UE, and the transport layer proxy function is applicable to all applications, or all services, of the second UE; alternatively, the UPF may execute the transport layer proxy function for some services (or some applications) of the second UE, and the transport layer proxy function is applicable to these applications, such as applications that may need to be transferred or shared, while for other applications of the second UE, the UPF does not execute the transport layer proxy function. The second UE may also send information about these applications to the SMF, and the application information may include, for example, the application identifier and / or triplet information. The application triplet information may include, for example, the application's target address, target port number, and transport layer protocol type (TCP or UDP).

[0130] If the transport layer proxy function is executed, the UPF performs proxy between the UE and the application server. For example, after the UPF receives service data from the UE, it will modify the source address of the service data to the address of the UPF before sending it to the application server. If this is the case, it is not necessary to require the PDU sessions with an associated relationship to have the same IP address. For example, the SMF or UPF can assign the same IP address to the first PDU session and the second PDU session, or different IP addresses. Even if the SMF assigns different IP addresses to the first PDU session and the second PDU session, since the UPF performs the transport layer proxy function, the first PDU session and the second PDU session are still considered to have an associated relationship for network elements such as the SMF and AMF. Because for the application server, the source addresses of the service data sent by the PDU sessions with an associated relationship are the same, both are the addresses of the UPF. The application server can regard the PDU sessions with an associated relationship as the same PDU session, or regard the service data from these PDU sessions as coming from the same UE. Therefore, if business data needs to be transferred or shared between associated PDU sessions, the application server does not need to re-establish the connection. The application server may not be aware of this and continue to transmit business data normally, thereby reducing the time of business interruption and even ensuring uninterrupted business.

[0131] If the transport layer proxy function is not performed, after the UPF receives the service data from the UE, it will not modify the source address of the service data, but forward the service data to the application server. If this is the case, the UPF or SMF can assign the same IP address to the first PDU session and the second PDU session, and the first PDU session and the second PDU session can reflect the association relationship by having the same IP address. If the IP address of the first PDU session and the IP address of the second PDU session are the same, for the application server, it will be considered that the service data received from the first PDU session and the service data received from the second PDU session are from the same PDU session, or from the same UE. Therefore, if it is necessary to transfer or share service data between PDU sessions with an associated relationship, it is not necessary for the application server to re-establish the connection. The application server may not be aware of this, but continue to transmit service data normally, thereby reducing the time of service interruption and even ensuring that the service is not interrupted.

[0132] In addition, if the UPF does not perform TCP proxy, a TCP connection needs to be established between the first UE and the application server, and a TCP connection also needs to be established between the second UE and the application server. Alternatively, since a TCP connection has already been established between the second UE and the application server, there is no need to establish a TCP connection between the first UE and the application server. The second UE sends the TCP connection information (e.g., at least one of the socket, the server's IP address, port number, the UE's IP address, or port number) to the first UE, and the first UE uses this TCP connection to communicate with the application server. If the UPF performs TCP proxy, the UE does not need to establish a TCP connection with the application server, but can establish a TCP connection with the UPF. For example, the first UE and the second UE can each establish a TCP connection with the UPF; or, if the first UE establishes a TCP connection with the UPF, the second UE does not need to establish a TCP connection with the UPF. The first UE or the UPF sends the TCP connection information (e.g., at least one of the socket, the server's IP address, port number, the UE's IP address, or port number) established between the first UE and the UPF to the second UE, so that the second UE and the UPF can use this TCP connection.

[0133] In addition, if the UPF does not execute the UDP proxy, since the second UE sends and receives data to and from the application server first, the second UE will send the information of sending and receiving data to and from the application server (at least one of the information such as the IP address and port number of the server side, the IP address or port number of the UE side) to the first UE, and the first UE can use this information to communicate with the application server.

[0134] S306. The UPF sends a thirteenth message to the SMF. Accordingly, the SMF receives the thirteenth message from the UPF. For example, if the ninth message is an N4 session modification request, the thirteenth message may be an N4 session modification response. That is, the thirteenth message may be considered a response to the ninth message.

[0135] The thirteenth message may include information such as the UPF address and port number allocated by the UPF to the first tunnel.

[0136] S307. The SMF sends information such as the UPF address and port number corresponding to the first tunnel to the first access network device. The corresponding access network device receives information such as the UPF address and port number corresponding to the first tunnel. For example, the SMF may send information such as the UPF address and port number corresponding to the first tunnel to the first AMF, and the first AMF then sends information such as the UPF address and port number corresponding to the first tunnel to the first access network device. In this case, the first access network device receives information such as the UPF address and port number corresponding to the first tunnel from the first AMF. The first access network device is the access network device serving the first UE.

[0137] S308. SMF sends a message to the second UE for accepting the establishment of the second PDU session. Correspondingly, the second UE receives a message from the SMF for accepting the establishment of the second PDU session. The message includes, for example, PDU session establishment accept. PDU session establishment accept can be used to indicate the acceptance of establishing the second PDU session. PDU session establishment accept can be encapsulated by SMF in an N1 SM container, i.e., N1 SM container (PDU session establishment accept).

[0138] It should be noted that when SMF sends a message to UE, it generally needs to be forwarded through AMF. Therefore, SMF can call the service provided by the second AMF and send the N1 SM container (PDU session establishment accept) to the second AMF. The service is, for example, the Namf_Communication_N1N2MessageTransfer service. After the second AMF receives the N1 SM container (PDU session establishment accept), it encapsulates it into a NAS message, that is, NASmessage (N1 SM container (PDU session establishment accept)), and then sends the eighth message to the second UE. The eighth message may include the NAS message (N1 SM container (PDU session establishment accept)). For example, the eighth message sent by the second AMF is N2message, but the N2message is sent to the second access network device. The N2 information includes the NAS message (N1 SM container (PDU session establishment accept)). The N2message is, for example, an N2 PDU session request. After the second access network device receives the N2message, it sends the NAS message (N1 SM container (PDU session establishment accept)) to the UE through the RRC message. The RRC message is, for example, an AN specific resource setup. In summary, PDUsession establishment accept can be included in the N1 SM container, and the N1 SM container is included in Namf_Communication_N1N2MessageTransfer, N2 PDU session request, and AN specific resource setup. Among them, N2message refers to the information sent by the AMF (for example, the second AMF) to the access network device (for example, the second access network device) through the N2 interface.

[0139] Optionally, the Namf_Communication_N1N2MessageTransfer sent by the SMF to the second AMF may further include third association indication information, where the third association indication information may indicate that the second PDU session is established as a PDU session with an associated relationship (for example, indicating that the second PDU session is established as a multi-UE PDU session). After receiving the third association indication information, the second AMF may store information that the second PDU session is a PDU session with an associated relationship (for example, information that the second PDU session is of a multi-UE PDU session type).

[0140] Optionally, the SMF may also send a second parameter to the second UE, where the second parameter may indicate a method for performing data processing on the PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship. For more information about the second parameter, please refer to Figure 2 The embodiment shown. If the SMF creates the second PDU session as a PDU session without an associated relationship, the SMF may not need to send the second parameter to the second UE. The second parameter may be included in the message used to accept the establishment of the second PDU session. For example, the second AMF may send the second parameter to the second UE through the eighth message; or, the SMF may send the second parameter through other messages, and the second AMF may send the second parameter to the second UE through other messages instead of the eighth message. Figure 3 Take the example of the SMF sending the second parameter to the second UE through a message for accepting the establishment of the second PDU session.

[0141] For the UE, if the second parameter is received from the SMF, it can be determined that the second PDU session is a PDU session with an association relationship, and if the second parameter is not received from the SMF, it can be determined that the second PDU session is a PDU session without an association relationship. Alternatively, if the SMF creates the second PDU session as a PDU session with an association relationship, then in addition to sending the second parameter to the second UE, the SMF may also send fourth association indication information to the second UE. The fourth association indication information may indicate that the second PDU session is a PDU session with an association relationship, and the UE may determine that the second PDU session is a PDU session with an association relationship based on the fourth association indication information; and if the SMF creates the second PDU session as a PDU session without an association relationship, then in addition to not sending the second parameter to the second UE, the SMF may not send the fourth association indication information to the second UE. If the second UE does not receive the fourth association indication information from the SMF, it can be determined that the second PDU session is a PDU session without an association relationship. Alternatively, if the SMF creates the second PDU session as a PDU session without an association relationship, the SMF may, in addition to not sending the second parameter to the second UE, also send fourth association indication information to the second UE. The fourth association indication information may indicate that the second PDU session is a PDU session without an association relationship. The UE may determine that the second PDU session is a PDU session without an association relationship based on the fourth association indication information. If the SMF creates the second PDU session as a PDU session with an association relationship, the SMF may, in addition to sending the second parameter to the second UE, not send the fourth association indication information to the second UE. If the second UE does not receive the fourth association indication information from the SMF, it can be determined that the second PDU session is a PDU session with an association relationship.

[0142] As described above, the SMF accepts the establishment of a PDU session for the second UE. If the SMF refuses to establish a PDU session for the first UE (that is, neither a PDU session with an associated relationship nor a PDU session without an associated relationship is established), S308 can be replaced by the SMF sending a message to the second UE for refusing to establish the second PDU session. Accordingly, the second UE receives a message from the SMF for refusing to establish the second PDU session. The message includes, for example, PDU session establishment reject, and PDU session establishment reject can be used to indicate the refusal to establish the second PDU session, or to indicate the refusal to establish a PDU session with an associated relationship, or to indicate the refusal to establish a PDU session.

[0143] S309: The second access network device sends information about the fifth tunnel to the SMF. Correspondingly, the SMF receives information about the fifth tunnel from the second access network device.

[0144] The second access network device allocates tunnel information for data transmission and reception between the UPF and the second access network device for the N4 session. This tunnel is, for example, called a fifth tunnel. The fifth tunnel is an access network tunnel used by the UPF to send data for the second UE to the second access network device. Information about the fifth tunnel includes, for example, the address of the second access network device and an identifier of the fifth tunnel.

[0145] The second access network device may send information about the fifth tunnel to the second AMF, and the second AMF may send the information about the fifth tunnel to the SMF. For example, the second access network device sends an N2 PDU session response to the second AMF, and the N2 PDU session response may include information about the fifth tunnel. The second AMF invokes a service provided by the SMF to send information about the fifth tunnel to the SMF, such as Nsmf_PDUSession_Update SMContext Request.

[0146] S310: The SMF sends information about the fifth tunnel to the UPF. Correspondingly, the UPF receives information about the fifth tunnel from the SMF.

[0147] For example, the SMF sends an N4 session modification message to the UPF to send the information of the fifth tunnel to the UPF.

[0148] S311. The second AMF stores information that the second PDU session is a PDU session with an associated relationship.

[0149] In S308, it is introduced that the Namf_Communication_N1N2MessageTransfer sent by the SMF to the second AMF may include third association indication information. The second AMF may store information that the second PDU session is a PDU session with an associated relationship according to the third association indication information (for example, information that the second PDU session is of multi-UE PDUsession type). Optionally, the second AMF may also store the identifier of the second PDU session and information such as the identifier of the SMF storing the service for the second PDU session.

[0150] Among them, S302 to S307 and S308 to S311 are all optional steps. In addition, the UE PDU session establishment process may also include other steps, which are not limited in the embodiment of the present application and will not be described in detail.

[0151] Through the solution provided by the embodiment of the present application, the second UE establishes a second PDU session, and the second PDU session is a PDU session with an associated relationship, that is, the second PDU session can establish an associated relationship with other PDU sessions. For example, the transfer of service data can be performed between PDU sessions with an associated relationship, and the service data of the first PDU session can be transferred to the second PDU session, or the service data of the second PDU session can be transferred to the first PDU session. Regardless of the transfer, the first PDU session and the second PDU session are both established PDU sessions. When performing media transfer, there is no need to establish a session first and then transfer, but the transfer can be performed directly, thereby reducing the service interruption time during the media transfer process, and even the service does not need to be interrupted during the media transfer process, thereby improving the transmission quality of the service and also improving the user experience.

[0152] After the second UE and the first UE establish PDU sessions respectively, service transfer or sharing can be performed between the PDU sessions. The third communication method provided in the embodiment of the present application is introduced below, through which service transfer or sharing can be achieved between PDU sessions. Figure 4 , which is a flowchart of the method.

[0153] S401: A second UE sends information about a first service to an SMF. Accordingly, the SMF receives the information about the first service. The SMF is the SMF serving the second PDU session, and the first service is a service that needs to be transferred or shared between associated PDU sessions. For example, the second UE sends information about the first service to the SMF via NAS information.

[0154] The information of the first service may include, for example, one or more of the following: a QoS flow identifier (QFI) corresponding to the first service, a QoS rule, a packet filter, an identifier of the first service, and packet information for describing the data flow of the first service. The QFI corresponding to the first service is used to indicate the QoS flow corresponding to the second UE for transmitting the first service. The QoS rule can be used by the second UE to map the first service to the QoS flow corresponding to the first service for transmission according to the QoS rule. The packet filtering rule can be used by the UPF to determine that the data packet is a data packet corresponding to the first service according to the packet filtering rule. For information about the identifier of the first service and the packet information for describing the data flow of the first service, please refer to Figure 2 Description of the illustrated embodiment.

[0155] Optionally, the second UE may also send a first processing method, or in other words, send information about the first processing method, to the SMF. The first processing method is the method by which the first service is transferred or shared. For example, the first processing method is to transfer the data of the first service between the second UE and another UE (e.g., the first UE), or to transfer the data of the first service between the PDU session of the other UE and the second PDU session. This method is considered to be the transfer of the first service. For example, the data of the first service is transferred from the PDU session of the other UE to the second PDU session, or the data of the first service is transferred from the second PDU session to the PDU session of the other UE. Alternatively, the first processing method is to transmit the data of the first service between the second UE and another UE (e.g., the first UE), or to transmit the data of the first service between the PDU session of the other UE and the second PDU session. This method is considered to be the sharing of the first service. For example, the data of the first service is transmitted on both the PDU session of the other UE and the second PDU session, and the first service transmitted on the PDU session of the other UE and the second PDU session may be the same. The PDU session of the other UE is associated with the second PDU session, for example, the other UE includes the first UE, and the PDU session of the other UE includes the first PDU session.

[0156] For example, the second UE initiates a PDU session modification process to achieve service transfer or sharing through the PDU session modification process. The second UE can send information about the first service (or, send information about the first service and the first processing method) to the SMF in the PDU session modification process. For example, the second UE sends information about the first service (or, sends information about the first service and the first processing method) to the SMF through a NAS message. The NAS message includes a PDU session modification request. The second UE sends the NAS message to the second AMF, and the second AMF calls the service provided by the SMF and sends the PDU session modification request and information about the first service (or, the PDU session modification request, information about the first service and the first processing method) and other contents to the SMF. The service provided by the SMF is, for example, a PDU session update (Nsmf_PDUSession_Update).

[0157] Next, the PDU session modification process of the second UE may be executed, so optionally, the method may include S402a to S407a, which is the PDU session modification process of the second UE.

[0158] S402a, SMF calls the service provided by the second AMF and sends a message to the second AMF. Correspondingly, the second AMF receives the message from the SMF. The second AMF is the AMF serving the second PDU session, and the service provided by the second AMF is, for example, N1N2 transfer (Namf_N1N2transfer). Figure 4 For example, the message is called an N1N2 transmission message.

[0159] Optionally, the second AMF may also send a response to the SMF.

[0160] S403a. The second AMF sends a message to the second access network device. Correspondingly, the second access network device receives the message from the second AMF. The second access network device is the access network device serving the second UE. The message is, for example, N2 message ( Figure 4 Taking this as an example), the N2 message may include a NAS message from the second UE.

[0161] S404a, the second access network device sends a message to the second UE. Correspondingly, the second UE receives the message from the second access network device. The message is, for example, an access network specific resource modification message. Figure 4 Taking this as an example, the AN specific resource modification message may include a PDU session modification command.

[0162] Optionally, the second UE may also send a response to the second access network device.

[0163] S405a. The second access network device sends a message to the second AMF. Correspondingly, the second AMF receives the message from the second access network device. For example, the message is an N2 PDU session response. Figure 4 Take this as an example.

[0164] S406a, the second AMF calls the service provided by SMF to send a message to SMF. Correspondingly, SMF receives the message from the second AMF. The service provided by SMF is, for example, Nsmf_PDUSession_Update. Figure 4 For example, the message is called a PDU session update message.

[0165] S407a, SMF sends a message to UPF. Correspondingly, UPF receives the message from SMF. The message is, for example, an N4 session modification message. Figure 4 Take this as an example.

[0166] The UPF is the UPF serving the second UE, or the UPF serving the second PDU session. According to the introduction of the aforementioned embodiment, PDU sessions with an associated relationship can share the same N4 session. Therefore, optionally, the UPF serving the PDU sessions with an associated relationship in the embodiment of the present application can be the same UPF. For example, the UPF serving the second UE is the same UPF as the UPF serving the first UE.

[0167] In various embodiments of the present application, the N4 session is used by the SMF to control the functions of the UPF associated with the PDU session, including the UPF detecting, classifying, performing QoS management, and determining routing for the PDU session data. By creating an N4 session, the UPF has an N4 session context corresponding to the PDU session, so that the UPF can detect, classify, perform QoS management, and determine routing for the PDU session data based on the N4 session context information.

[0168] Optionally, UPF may also send a response to SMF.

[0169] In addition to executing the PDU session modification process for the second UE, since the data transfer or sharing of the first service involves the second PDU session, the PDU session modification process for the first UE may also be optionally executed. Therefore, the method may include S402b to S408b, which are the PDU session modification process for the first UE.

[0170] S402b, SMF sends a message to UPF. Correspondingly, UPF receives the message from SMF. This message can also be called the tenth message. This message is, for example, N4 session modification. Figure 4 Take this as an example.

[0171] SMF can configure a QoS flow for transmitting the first service for the first PDU session of the first UE based on the information of the first service (or based on the information of the first service and the first processing method). For example, SMF can configure a first QoS flow for the first UE to transmit the first service, and the first QoS flow is the QoS flow used by the second UE to transmit the first service, and the first QoS flow is associated with the second PDU session. SMF can configure a first QoS flow for the first UE to transmit the first service, and the first QoS flow is also associated with the first PDU session. In other words, SMF can configure the first PDU session and the second PDU session to share the first QoS flow. At this time, the first PDU session and the second PDU session can correspond to the same QFI, that is, the QFI of the first QoS flow. For example, if the first service is to be transferred from the second PDU session to the first PDU session, the first service does not need to switch the QoS flow and can continue to be transmitted on the first QoS flow. This method can reduce the number of QoS flows and simplify the implementation process. You can refer to Figure 5A , the first service is transmitted between the first UE and the second UE and the UPF through the first QoS flow.

[0172] For another example, the SMF can configure a second QoS flow for the first UE to transmit the first service, and the second QoS flow is associated with the first PDU session. The QoS flow used by the second UE to transmit the first service is the first QoS flow, and the first QoS flow is associated with the second PDU session. The first QoS flow and the second QoS flow are different QoS flows. In other words, the SMF configures different QoS flows for the first PDU session and the second PDU session to transmit the first service. At this time, the first PDU session corresponds to the QFI of the second QoS flow, and the second PDU session corresponds to the QFI of the first QoS flow. This method is conducive to the separate management of PDU sessions. Please refer to Figure 5B , the first service is transmitted between the first UE and the UPF through the second QoS flow, and the first service is transmitted between the second UE and the UPF through the first QoS flow.

[0173] After the SMF determines that the QoS flow for transmitting the first service is configured for the first PDU session of the first UE according to the above mechanism, it can send a tenth message to the UPF to modify the N4 session. Wherein, the content indicated by the tenth message may also be different depending on the way the SMF configures the QoS flow.

[0174] If the SMF has configured the first QoS flow for both the first PDU session and the second PDU session to transmit the first service, then the tenth message can be used to modify the N4 session and allocate the second tunnel. At this time, the second tunnel is associated with the first QoS flow. The second tunnel is, for example, the access network tunnel corresponding to the first service. The second tunnel is used for data transmission and reception between the UPF and the access network device, and is the CN tunnel corresponding to the second UE. Among them, the UPF allocates the second tunnel, for example, the UPF allocates the UPF address and port number to the second tunnel. The second tunnel can be used by the second access network device to send data of the first service to the UPF. In addition, the tenth message can also indicate the transfer of data between different UEs through the first tunnel and the second tunnel, or indicate the sending of the same data to different UEs. The first tunnel can be used by the second access network device to send data of the first service to the UPF. For an introduction to the first tunnel, please refer to Figure 3 In the illustrated embodiment, S301. If the tenth message indicates that data is transferred between different UEs via the first tunnel and the second tunnel, the UPF may, based on the tenth message, modify the access network tunnel corresponding to the first QoS flow from the first tunnel to the second tunnel, so as to transfer the data of the first service from the second UE to the first UE (or modify the access network tunnel corresponding to the first QoS flow from the second tunnel to the first tunnel, so as to transfer the data of the first service from the first UE to the second UE); or, if the tenth message indicates that the same data is sent to different UEs, the UPF may modify the access network tunnel corresponding to the first QoS flow from the first tunnel to the first tunnel and the second tunnel (or modify the second tunnel to the first tunnel and the second tunnel), that is, so that the first QoS flow corresponds to two tunnels, so as to transmit the data of the first service on the first UE and the second UE, or in other words, to share the data of the first service on the first UE and the second UE, wherein the data of the first service transmitted by the first UE and the data of the first service transmitted by the second UE may be the same, and therefore also be considered a duplicate. Whether the tenth message indicates data transfer or data sharing can be determined according to the first processing method, or if the SMF does not receive the first processing method, the SMF can determine it on its own, for example, based on the type of the first service.

[0175] To make the instructions to the UPF clearer, the SMF may optionally send a second indication message to the UPF. The second indication message may indicate that the access network tunnel corresponding to the first QoS flow is set to the first tunnel or the second tunnel, or that the access network tunnel corresponding to the first QoS flow is the first tunnel and the second tunnel. For example, if the tenth message indicates that data is transferred between different UEs via the first tunnel and the second tunnel, the second indication message may indicate that the access network tunnel corresponding to the first QoS flow is set to the first tunnel or the second tunnel. Based on the second indication message, the UPF may change the access network tunnel corresponding to the first QoS flow from the first tunnel to the second tunnel to enable data of the first service to be transferred from the second UE to the first UE, or change the access network tunnel corresponding to the first QoS flow from the second tunnel to the first tunnel to enable data of the first service to be transferred from the first UE to the second UE. Alternatively, if the tenth message indicates that the same data is to be sent to different UEs, the second indication message may indicate that the access network tunnel corresponding to the first QoS flow is the first tunnel and the second tunnel. Based on the second indication message, the UPF may change the access network tunnel corresponding to the first QoS flow from the first tunnel to the first tunnel and the second tunnel, or from the second tunnel to the first tunnel and the second tunnel.

[0176] Alternatively, if the SMF configures a second QoS flow for the first PDU session to transmit the first service, and configures a first QoS flow for the second PDU session to transmit the first service, then the tenth message can be used to modify the N4 session and allocate a second tunnel. In this case, the second tunnel is associated with the second QoS flow. The second tunnel is, for example, the access network tunnel corresponding to the first service. The second tunnel is used for data transmission and reception between the UPF and the access network device, and is the CN tunnel corresponding to the second UE. The UPF allocates the second tunnel, for example, the UPF allocates the UPF address and port number to the second tunnel. The second tunnel can be used by the second access network device to send data of the first service to the UPF. In addition, the tenth message can also indicate the transfer of data between different UEs through the first QoS flow and the second QoS flow, or indicate the sending of the same data to different UEs. If the tenth message indicates that data is transferred between different UEs through the first QoS flow and the second QoS flow, the UPF may modify the QoS flow corresponding to the first service from the first QoS flow to the second QoS flow according to the instruction of the tenth message, so as to realize the transfer of data of the first service from the second UE to the first UE, or modify the QoS flow corresponding to the first service from the second QoS flow to the first QoS flow, so as to realize the transfer of data of the first service from the first UE to the second UE; or, if the tenth message indicates that the same data is sent to different UEs, the UPF may modify the QoS flow corresponding to the first service from the first QoS flow to the first QoS flow and the second QoS flow according to the instruction of the tenth message, or modify the QoS flow corresponding to the first service from the second QoS flow to the first QoS flow and the second QoS flow, that is, the first service corresponds to two QoS flows, so as to realize the transmission of data of the first service on the first UE and the second UE, or realize the sharing of data of the first service on the first UE and the second UE, wherein the data of the first service transmitted by the first UE and the data of the first service transmitted by the second UE may be the same, and therefore are also regarded as copies. Whether the tenth message indicates data transfer or data sharing can be determined according to the first processing method, or if the SMF does not receive the first processing method, the SMF can determine it by itself, for example, according to the type of the first service.

[0177] To make the instructions to the UPF clearer, the SMF may optionally send a second indication message to the UPF. The second indication message may indicate that the data flow of the first service is to be transmitted through the first QoS flow or the second QoS flow, or that the data flow of the first service is to be transmitted through the first QoS flow and the second QoS flow. For example, if the tenth message indicates that data is to be transferred between different terminal devices through the first QoS flow and the second QoS flow, the second indication message may indicate that the data flow of the first service is to be transmitted through the first QoS flow or the second QoS flow. Based on the second indication message, the UPF may modify the QoS flow corresponding to the first service from the first QoS flow to the second QoS flow to achieve data transfer of the first service from the second UE to the first UE, or modify the QoS flow corresponding to the first service from the second QoS flow to the first QoS flow to achieve data transfer of the first service from the first UE to the second UE; or, if the tenth message indicates that the same data is to be sent to different UEs, the second indication message may indicate that the data flow of the first service is to be transmitted through the first QoS flow and the second QoS flow. Based on the second indication message, the UPF may modify the QoS flow corresponding to the first service from the first QoS flow to the first QoS flow and the second QoS flow, or modify the QoS flow corresponding to the first service from the second QoS flow to the first QoS flow and the second QoS flow.

[0178] Among them, the SMF instructs the UPF to modify the QoS flow corresponding to the first service. One way is for the SMF to modify the mapping relationship between the data packet and the QFI. For example, the SMF will send the packet detection rule (PDR) corresponding to the first service to the UPF, and the PDR can be used by the UPF to filter out the data packets of the first service. The PDR may include a QoS enforcement rule (QER), and the QER may include a QFI. That is, the data packets that can be applied to the PDR will be mapped by the UPF to the QoS flow corresponding to the QFI included in the QER for transmission. For example, the SMF modifies the QFI included in the QER from QFI 1 to QFI 2, and after the UPF receives the PDR, it transfers the first service from the second UE to the first UE; or, the SMF modifies the QFI included in the QER from QFI1 to QFI 1 and QFI 2, so as to transmit the first service on the first UE and the second UE, and after the UPF receives the PDR, it transfers the first service from the second UE to the first UE. Among them, QFI 1 is the QFI of the first QoS flow, and QFI 2 is the QFI of the second QoS flow.

[0179] Optionally, after receiving the tenth message, UPF may also send a response to SMF.

[0180] Alternatively, S407a and S402b may be executed in combination. For example, the N4 session modification message in S407a and the tenth message are the same message.

[0181] S403b. After configuring the QoS flow for transmitting the first service for the first PDU session of the first UE according to S402b, the SMF calls the service provided by the first AMF and sends a message to the first AMF. The message includes information sent to the access network device and the first UE respectively for configuring the QoS flow for transmitting the first service for the first PDU session of the first UE. Accordingly, the first AMF receives the message from the SMF. The first AMF is the SMF serving the first PDU session. The service provided by the first AMF is, for example, Namf_N1N2transfer. Figure 4 In the embodiment of the present application, the SMF serving the first PDU session and the SMF serving the second PDU session are, for example, the same SMF. The information sent to the access network device for configuring a QoS flow for transmitting the first service for the first PDU session of the first UE includes CN tunnel information allocated by the UPF to the QoS flow.

[0182] Optionally, the second AMF may also send a response to the SMF.

[0183] S404b. The first AMF sends a message to the first access network device. Correspondingly, the first access network device receives the message from the first AMF. The first access network device is the access network device serving the first UE. The message is, for example, an N2 message. Figure 4 Taking this as an example, the N2 message may also be referred to as the third message, and the N2 message may include a NAS message (the tenth message) sent by the SMF to the first UE. For example, the N2 message includes information about the QoS flow of the application transmission first service configured by the SMF for the first UE, such as QFI.

[0184] S405b. The first access network device sends a message to the first UE. Correspondingly, the first UE receives the message from the first access network device. The message includes a NAS message (PDU session modification command, the part of the N1N2 transmission message in S403b sent by the SMF to the first UE). The message is, for example, an access network dedicated resource setup message. Figure 4Taking this as an example, the AN specific resource setup may include the wireless bearer configured by the first access network device based on the QoS flow information sent by the SMF to the first access network device in the N1N2 transmission message of S403b, and also include a PDU session modification command. The PDU session modification command includes, for example, the ID of the first PDU session and the QoS rule corresponding to the first PDU session and other information.

[0185] Optionally, the first UE may also send a response to the first access network device.

[0186] S406b. The first access network device sends a message to the first AMF. Correspondingly, the first AMF receives the message from the first access network device. The message is, for example, an N2 PDU session response. Figure 4 Taking this as an example, the message includes AN tunnel information allocated by the first access network device to transmit the QoS flow of the first service.

[0187] S407b, the first AMF calls the service provided by SMF to send a message to SMF. Correspondingly, SMF receives the message from the first AMF. The service provided by SMF is, for example, Nsmf_PDUSession_Update. Figure 4 For example, the message is called a PDU session update message.

[0188] S408b, SMF sends a message to UPF. Correspondingly, UPF receives the message from SMF. The message is, for example, N4session modification message. Figure 4 Taking this as an example, the message may include AN tunnel information allocated by the first access network device for transmitting the QoS flow of the first service.

[0189] Optionally, after receiving the N4 session modification message, the UPF may also send a response to the SMF.

[0190] Optionally, the N4 session modification message may also indicate the transfer of data between different UEs via the first tunnel and the second tunnel, or indicate the sending of the same data to different UEs. For an introduction to features such as the first tunnel and the second tunnel, refer to S402b.

[0191] Optionally, the SMF may also send second indication information to the UPF. The second indication information may indicate that the access network tunnel corresponding to the first QoS flow is set to the first tunnel or the second tunnel, or that the access network tunnel corresponding to the first QoS flow is the first tunnel or the second tunnel; or the second indication information may indicate that the data flow of the first service is transmitted through the first QoS flow or the second QoS flow, or that the data flow of the first service is transmitted through the first QoS flow and the second QoS flow. For more information about this part, please refer to S402b.

[0192] In the above approach, N4 session modification is achieved by instructing the UPF to modify the tunnel or QoS flow. Alternatively, N4 session modification can be achieved by updating a multi-UE rule to the UPF. In this case, the N4 session modification message may still indicate modification of the N4 session and allocation of a second tunnel, but may not indicate service transfer or sharing. For example, the SMF sends an updated multi-UE rule to the UPF. The multi-UE rule may indicate transfer of a first service from a first UE to a second UE. Based on the multi-UE rule, the UPF may send the downlink data of the first service to the access network tunnel corresponding to the second UE. Alternatively, the multi-UE rule may indicate transfer of the first service from the second UE to the first UE. Based on the multi-UE rule, the UPF may send the downlink data of the first service to the access network tunnel corresponding to the first UE. Alternatively, the multi-UE rule may indicate transfer of the first service to a first UE and a second UE. Based on the multi-UE rule, the UPF may send the downlink data of the first service to both the access network tunnel corresponding to the first UE and the access network tunnel corresponding to the second UE.

[0193] In addition, in S401, the second UE sends the first service information to the SMF as an example. Alternatively, the second UE may send the first service information (or the first service information and the first processing method) to the first UE, and the first UE sends the first service information (or the first service information and the first processing method) to the SMF, that is, the first UE initiates the PDU session modification process.

[0194] from Figure 4 It can be seen that in the execution Figure 4 Before the embodiment shown, the application server sends the data of the first service to the second UE. Figure 4After the embodiment shown, the application server can send data of the first service to the first UE and the second UE (the service data of the second PDU session is shared on the first PDU session and the second PDU session), or, the application server can send data of the first service to the first UE and no longer send data of the first service to the second UE (the service data of the second PDU session is transferred to the first PDU session).

[0195] In the embodiment of the present application, since the first PDU session and the second PDU session are associated with each other, the business data of the first PDU session can be transferred to the second PDU session, or the business data of the second PDU session can be transferred to the first PDU session, or the business data of the second PDU session can be shared between the first PDU session and the second PDU session. Regardless of the transfer or sharing, the first PDU session and the second PDU session are both established PDU sessions. When performing media transfer or sharing, there is no need to establish a session before transferring, but the transfer or sharing can be performed directly, thereby reducing the time of business interruption during the media transfer or sharing process, and even the business does not need to be interrupted during the media transfer or sharing process, thereby improving the transmission quality of the business and also improving the user experience.

[0196] exist Figure 2 、 Figure 3 as well as Figure 4 In the embodiment shown, the first UE first establishes the first PDU session and then transfers or shares the service. There is also a possibility that the first UE can transfer or share the service during the process of establishing the first PDU session, so that the first UE does not need to perform the subsequent PDU session modification process, which can simplify the process of service transfer or sharing and improve processing efficiency. To this end, the embodiment of the present application provides a fourth communication method to introduce the process. Please refer to Figure 6 , which is a flowchart of the method.

[0197] S601: A second UE sends a transfer request to a first UE. Correspondingly, the first UE receives the transfer request from the second UE.

[0198] The transfer request is used, for example, to request that the first service of the second UE be transferred to the first UE, or to request that the first service be shared between the first UE and the second UE. The transfer request may include an identifier of the second PDU session, an identifier of the second UE (e.g., the first identifier of the second UE or the second identifier of the second UE), and information about the first service. Optionally, the transfer request may also include connection parameters. For an introduction to these features, reference may be made to any of the aforementioned embodiments.

[0199] S602. The first UE sends a response message to the second UE. Accordingly, the second UE may receive the response message from the first UE. The response message may be used to indicate whether the transfer or sharing of the first service is permitted. For example, the response message may also include an identifier of the first UE (e.g., a first identifier of the first UE or a second identifier of the second UE).

[0200] S603: The second UE sends information about the first service to the SMF. Correspondingly, the SMF receives the information about the first service. After receiving the information about the first service, the SMF may store the information about the first service.

[0201] For more information about S603, please refer to Figure 4 S401 in the embodiment shown.

[0202] For example, if the second UE sends the information of the first service to the SMF by initiating the PDU session modification process, then the N4 session modification process of the second UE can be executed. Figure 4 The description of the embodiment shown will not be repeated here.

[0203] S604: The second UE sends a trigger message to the first UE. Correspondingly, the first UE receives the trigger message from the second UE.

[0204] The trigger message may indicate the establishment of a PDU session. Because the second UE believes that the first service needs to be transferred or shared, the second UE may trigger the second UE to establish a PDU session.

[0205] S605: The first UE sends a first message to the first AMF. Accordingly, the first AMF receives the first message from the first UE. The first message may request establishment of a PDU session for the first UE. For example, the PDU session is referred to as a first PDU session.

[0206] For more information about S605, please refer to Figure 2 S201 in the embodiment shown.

[0207] S606. The first AMF selects an SMF for the first PDU session based on the identifier of the second UE (e.g., the first identifier of the second UE) and the identifier of the second PDU session.

[0208] For more information about S606, please refer to Figure 2 S203 in the embodiment shown.

[0209] S607: The first AMF sends a fifth message to the SMF. Correspondingly, the SMF receives the fifth message from the first AMF. The fifth message may request establishment of a first PDU session with an associated relationship for the first UE.

[0210] For more information about S607, please refer to Figure 2 S204 in the embodiment shown.

[0211] S608. The SMF determines whether to establish a PDU session with an associated relationship for the first UE.

[0212] For more information about S608, please refer to Figure 2 S205 in the embodiment shown.

[0213] S609: The SMF sends the tenth message to the UPF. Correspondingly, the UPF receives the tenth message from the SMF.

[0214] For more information about S609, please refer to Figure 4 S402b in the embodiment shown.

[0215] S610. The SMF sends a message to the first UE for accepting the establishment of the first PDU session. Correspondingly, the first UE receives a message from the SMF for accepting the establishment of the first PDU session. The message includes, for example, a PDU session establishment accept, where the PDU session establishment accept may be used to indicate acceptance of the establishment of the first PDU session.

[0216] When SMF sends a message to UE, it generally needs to be forwarded through AMF. Therefore, SMF can call the service provided by the first AMF and send the PDU session establishment accept to the first AMF. The service is, for example, the Namf_Communication_N1N2MessageTransfer service. After the first AMF receives the PDU session establishment accept, it sends a second message to the first UE. The second message may include the PDU session establishment accept. Optionally, the second message may also include information about the QoS flow configured by SMF for the first UE to transmit the first service, such as QFI. For example, the second message sent by the first AMF is N2 information (N2 message), but the N2 information is sent to the first access network device. The N2 information includes the PDU session establishment accept. The N2 information is, for example, an N2 PDU session request. After the first access network device receives the N2 information, it sends the PDU session establishment accept to the UE through an RRC message (RRC message). The RRC message is, for example, an access network dedicated resource establishment (AN specific resource setup). Among them, PDU session establishment accept can be included in the container, and Namf_Communication_N1N2MessageTransfer, N2 PDUsession request, and AN specific resource setup all include the container.

[0217] For more information about S610, please refer to Figure 2 S209 in the embodiment shown.

[0218] Alternatively, S603 to S605 may not be executed. After the first UE receives the transfer request from the second UE, it may initiate the process of establishing the first PDU session. For example, the first UE sends information about the first service to the SMF via a message for requesting to establish a PDU session.

[0219] Among them, S601 to S604 and S607 to S609 are optional steps.

[0220] from Figure 6 It can be seen that in the execution Figure 6Before the embodiment shown, the application server sends the data of the first service to the second UE. Figure 6 After the embodiment shown, the application server can send data of the first service to the first UE and the second UE (the service data of the second PDU session is shared on the first PDU session and the second PDU session), or, the application server can send data of the first service to the first UE and no longer send data of the first service to the second UE (the service data of the second PDU session is transferred to the first PDU session).

[0221] Through the method provided in the embodiment of the present application, service transfer or sharing can be achieved during the PDU session establishment process of the first UE. Compared with the aforementioned solution, this method can save execution steps and improve efficiency.

[0222] For example, a user uses a mobile phone to watch a video on a website on the way home, and a second PDU session is established between the mobile phone and the application server of the video to transmit the video. After returning home, the user turns on the smart TV. Before that, he uses the smart TV to log in to the same account to continue watching the video. Before that, the smart TV has established a first PDU session with the application server of the video, and the first PDU session is associated with the second PDU session. Then, when the user continues to watch the video on the smart TV, the smart TV no longer needs to establish a connection with the application server of the video, but can directly play the video. That is to say, during this media transfer process, when the next device is used to continue to receive media information, the service on the previous device can be directly transferred to the next device, reducing the time of service interruption and improving user experience.

[0223] For another example, a mobile phone and a PC belong to a UE group, and the mobile phone determines that it may transfer or share services with other UEs in the UE group. When the mobile phone establishes a PDU session for the video application on the mobile phone, it can trigger the establishment of a PDU session with an associated relationship, such as a second PDU session. For example, if the mobile phone believes that it may transfer or share services to the PC, the mobile phone can send information about the services to be transferred or shared to the PC, and the PC can establish a PDU session with an associated relationship, such as a first PDU session. Initially, the user plays the video provided by the video application through the mobile phone. The video application is an application determined by the mobile phone to be possible to transfer or share, and the second PDU session can transmit the video. Then, the mobile phone casts the video played on the mobile phone to the PC for playback through a direct communication path with the PC (such as wireless fidelity (Wi-Fi) direct connection, etc.), and the mobile phone continues to play the video at the same time, which is equivalent to sharing the video on the second PDU session and the first PDU session. During this process, if the mobile phone wants to exit the screen projection, the mobile phone can exit directly. For example, after the mobile phone exits, the video can be switched from shared mode to separate playback mode, that is, the video is switched to be transmitted through the first PDU session. That is, during the wireless screen projection process, the screen projection device (such as a mobile phone) can exit without affecting the output of the projected device (such as a PC). This reduces the dependence of the screen projection process on the screen projection device and makes the application of screen projection more flexible.

[0224] Figure 7 A schematic diagram of the structure of a communication device provided in an embodiment of the present application is given. The communication device 700 may be Figure 2 The embodiment shown, Figure 3 The embodiment shown, Figure 4 The embodiment shown, or Figure 6 The terminal device or the circuit system of the terminal device described in any of the embodiments shown is used to implement the method corresponding to the terminal device in the above method embodiment. The terminal device is, for example, the first terminal device or the second terminal device. Alternatively, the communication device 700 may be Figure 2 The embodiment shown, Figure 3 The embodiment shown, Figure 4 The embodiment shown, or Figure 6 The network device or circuit system of any of the illustrated embodiments is used to implement the method corresponding to the network device in the above-described method embodiments. The network device is, for example, a first network device, a second network device, or a fourth network device. For specific functions, refer to the description of the above-described method embodiments. For example, one circuit system is a chip system.

[0225] The communication device 700 includes at least one processor 701, a communication line 702, and at least one communication interface 704. As an optional embodiment, the communication device 700 may further include a memory 703. Since the memory 703 is not a required functional module but only an optional functional module, Figure 7 Indicated by a dotted box.

[0226] The processor 701 may include a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present application.

[0227] Communication link 702 may include a pathway for transmitting information between the aforementioned components.

[0228] The communication interface 704 uses any transceiver or other device for communicating with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area network (WLAN), wired access network, etc.

[0229] The memory 703 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 703 may exist independently and be connected to the processor 701 via the communication line 702. Alternatively, the memory 703 may be integrated with the processor 701.

[0230] The memory 703 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 701. The processor 701 is used to execute the computer-executable instructions stored in the memory 703, thereby implementing the communication method provided in the above embodiment of the present application.

[0231] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0232] In a specific implementation, as an embodiment, the processor 701 may include one or more CPUs, such as Figure 7 CPU0 and CPU1 in.

[0233] In a specific implementation, as an embodiment, the communication device 700 may include multiple processors, such as Figure 7 701 and processor 708 in FIG. Each of these processors may be a single-CPU processor or a multi-CPU processor. A processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0234] when Figure 7 When the device shown is a chip, such as a chip for an access network device, a UPF chip, an SMF chip, or a terminal device chip, the chip includes a processor 701 (which may also include a processor 708), a communication circuit 702, a memory 703, and a communication interface 704. Specifically, the communication interface 704 may be an input interface, a pin, or a circuit. The memory 703 may be a register, a cache, or the like. The processor 701 and the processor 708 may be a general-purpose CPU, a microprocessor, an ASIC, or one or more integrated circuits for controlling the execution of the program of any of the above-described embodiments of the communication method.

[0235] The embodiment of the present application can divide the functional modules of the device according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation. For example, in the case of dividing each functional module according to each function, Figure 8A schematic diagram of an apparatus is shown. The apparatus 800 may be an access network device, UPF, SMF, or terminal device involved in the above-mentioned various method embodiments, or a chip in an access network device, a chip in an SMF, a chip in a UPF, or a chip in a terminal device. The apparatus 800 includes a sending unit 801, a processing unit 802, and a receiving unit 803.

[0236] It should be understood that the device 800 can be used to implement the steps performed by the access network device, UPF, SMF or terminal device in the method of the embodiment of the present application. The relevant features can be referred to the various embodiments above and will not be repeated here.

[0237] Optional, Figure 8 The functions / implementation processes of the sending unit 801, the receiving unit 803 and the processing unit 802 can be realized by Figure 7 The processor 701 in the embodiment calls the computer execution instruction stored in the memory 703 to implement. Or, Figure 8 The function / implementation process of the processing unit 802 can be achieved by Figure 7 The processor 701 in the embodiment calls the computer execution instruction stored in the memory 703 to implement the above. Figure 8 The functions / implementation processes of the sending unit 801 and the receiving unit 803 can be achieved by Figure 7 This is achieved by the communication interface 704 in .

[0238] Optionally, when the device 800 is a chip or a circuit, the functions / implementation processes of the sending unit 801 and the receiving unit 803 can also be implemented through pins or circuits.

[0239] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When software is used for implementation, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0240] The various illustrative logic units and circuits described in the embodiments of the present application can be implemented or operated by a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The general-purpose processor can be a microprocessor, and optionally, the general-purpose processor can also be any conventional processor, controller, microcontroller or state machine. The processor can also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other similar configuration.

[0241] The steps of the methods or algorithms described in the embodiments of the present application can be directly embedded in hardware, software units executed by a processor, or a combination of the two. The software units can be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. For example, the storage medium can be connected to the processor so that the processor can read information from the storage medium and write information to the storage medium. Alternatively, the storage medium can also be integrated into the processor. The processor and storage medium can be provided in an ASIC, which can be provided in a terminal device. Alternatively, the processor and storage medium can also be provided in different components in the terminal device.

[0242] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0243] Although the embodiments of the present application have been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the embodiments of the present application. Accordingly, the embodiments of the present application and the accompanying drawings are merely illustrative illustrations of the embodiments of the present application as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the embodiments of the present application. Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present application without departing from the scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the embodiments of the present application and their equivalents, the embodiments of the present application are also intended to include these modifications and variations.

[0244] Embodiment 1. A communication method, applied to a first terminal device, comprising:

[0245] Sending a first message, where the first message is used to request establishment of a first PDU session for the first terminal device, the first message also including an identifier of a second terminal device and an identifier of a second PDU session, where the second PDU session is a PDU session of the second terminal device, and the identifier of the second terminal device and the identifier of the second PDU session are used by the first network device to select a second network device or to establish an association relationship between the first PDU session and the second PDU session;

[0246] A second message is received from the first network device, where the second message includes information for accepting establishment of the first PDU session.

[0247] Embodiment 2. According to the method of embodiment 1, the first message also includes a session establishment request message, wherein:

[0248] The identifier of the second terminal device and the identifier of the second PDU session are included in the session establishment request message; or,

[0249] The identifier of the second terminal device and the identifier of the second PDU session are included in the first message but are not included in the session establishment request message; or,

[0250] The identifier of the second terminal device and the identifier of the second PDU session are included in the session establishment request message, and are included in the bearer space in the first message except the session establishment request message.

[0251] Example 3. According to the method described in Example 1 or 2, the first message includes a first parameter, and the first parameter is used to indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship.

[0252] Example 4. According to the method described in any one of Examples 1 to 3, the second message also includes a second parameter, and the second parameter is used to indicate the manner in which the PDU session performs data processing, and the manner in which the data processing is performed includes transferring business data between the first PDU session and the second PDU session, or transmitting business data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

[0253] Example 5. The method according to any one of Examples 1 to 4, further comprising:

[0254] An identifier of the second terminal device and an identifier of the second PDU session are received from the second terminal device.

[0255] Example 6. The method according to any one of Examples 1 to 5, further comprising:

[0256] Information of a first service is received from the second terminal device, where the first service is a service to be transferred from the second terminal device to a target terminal device, where the target terminal device includes the first terminal device, or includes the second terminal device and the first terminal device.

[0257] Example 7. The method according to any one of Examples 1 to 6, further comprising:

[0258] Receive connection parameters from the second terminal device, where the connection parameters include slice information and / or data network name DNN corresponding to the second PDU session.

[0259] Embodiment 8. According to the method described in any one of Embodiments 1 to 7, the second message includes QoS flow information configured by the second network device for the first terminal device for transmitting the first service.

[0260] Example 9. The method according to any one of Examples 1 to 7, further comprising:

[0261] A third message is received from the first network device, where the third message includes QoS flow information configured by the second network device for the first terminal device to transmit the first service.

[0262] Embodiment 10. According to the method described in embodiment 8 or 9, the QoS flow information includes an identifier of the QoS flow, and the identifier of the QoS flow is the same as or different from the identifier of the QoS flow used by the second terminal device to transmit the first service.

[0263] Example 11. The method according to Examples 1 to 10, further comprising:

[0264] Sending information of the first service to the second network device, where the information of the first service includes an identifier of the first service and / or packet information used to describe a data flow of the first service.

[0265] Example 12. The method according to Example 11, further comprising:

[0266] Sending a first processing method to the second network device, wherein:

[0267] The first processing manner is to transfer the data of the first service between the first PDU session and the second PDU session, or to transmit the data of the first service on the first PDU session and the second PDU session; or,

[0268] The first processing manner is to transfer the data of the first service between the first terminal device and the second terminal device, or to transmit the data of the first service between the first terminal device and the second terminal device.

[0269] Example 13. The method according to any one of Examples 1 to 12, further comprising:

[0270] Send a first indication message to the second terminal device, where the first indication message is used to indicate that the first PDU session has been established and / or to trigger the data processing process of the PDU session.

[0271] Embodiment 14. A communication method, applied to a second terminal device, comprising:

[0272] Sending a sixth message to the first network device, where the sixth message is used to request establishment of a second PDU session for the second terminal device, the sixth message including a first parameter, where the first parameter is used to indicate that the second PDU session requested to be established by the second terminal device is a PDU session with an associated relationship and / or is used to select a second network device;

[0273] An eighth message is received from the first network device, where the eighth message includes information for accepting establishment of the second PDU session.

[0274] Example 15. According to the method described in Example 14, the eighth message also includes a second parameter, and the second parameter is used to indicate the way in which the PDU session performs data processing. The way of performing the data processing includes transferring business data between the second PDU session and the PDU session of other terminal devices, or transmitting business data on the second PDU session and the PDU session of the other terminal device, and the PDU session of the other terminal device has an associated relationship with the second PDU session, wherein the data processing can be performed between the PDU sessions with the associated relationship.

[0275] Example 16. The method according to Example 14 or 15, further comprising:

[0276] Send the identifier of the second terminal device and the identifier of the second PDU session to the first terminal device.

[0277] Example 17. The method according to any one of Examples 14 to 16, further comprising:

[0278] Information of a first service is sent to the first terminal device, where the first service is a service to be transferred from the second terminal device to a target terminal device, where the target terminal device includes the first terminal device, or includes the second terminal device and the first terminal device.

[0279] Example 18. The method according to any one of Examples 14 to 17, further comprising:

[0280] Send connection parameters to the first terminal device, where the connection parameters include slice information and / or data network name DNN corresponding to the second PDU session.

[0281] Example 19. The method according to any one of Examples 14 to 18, further comprising:

[0282] Information of the first service is sent to the second network device, where the information of the first service includes an identifier of the first service and / or packet information for describing a data flow of the first service.

[0283] Example 20. The method according to Example 19, further comprising:

[0284] Sending a first processing method to the second network device, wherein:

[0285] The first processing manner is to transfer the data of the first service between the PDU session of the other terminal device and the second PDU session, or to transmit the data of the first service on the PDU session of the other terminal device and the second PDU session; or

[0286] The first processing manner is transferring the data of the first service between the first terminal device and the second terminal device, or transmitting the data of the first service between the first terminal device and the second terminal device;

[0287] Among them, the PDU session of the other terminal device is associated with the second PDU session.

[0288] Embodiment 21. The method according to embodiment 19 or 20, before sending the information of the first service to the second network device, further comprising:

[0289] A first indication message is received from a first terminal device, where the first indication message is used to indicate that the first PDU session has been established and / or to trigger a data processing process for the PDU session.

[0290] Embodiment 22. A communication method, applied to a first network device, comprising:

[0291] Receive a first message, where the first message is used to request establishment of a first PDU session for a first terminal device, the first message also including an identifier of a second terminal device and an identifier of a second PDU session, where the second PDU session is a PDU session of the second terminal device;

[0292] According to the identifier of the second terminal device and the identifier of the second PDU session, a second network device is selected for the first PDU session, where the second network device is a network device serving the second PDU session.

[0293] Example 23. The method according to Example 22, further comprising:

[0294] A second message is sent to the first terminal device, where the second message includes information for accepting establishment of the first PDU session.

[0295] Embodiment 24. The method according to embodiment 22 or 23, further comprising:

[0296] The first message includes a first parameter, and the first parameter is used to indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship.

[0297] Example 25. The method according to any one of Examples 22 to 24, further comprising:

[0298] A second parameter is sent to the first terminal device, where the second parameter is used to indicate a manner in which the PDU session performs data processing, where the manner in which the data processing is performed includes transferring service data between the first PDU session and the second PDU session, or transmitting service data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

[0299] Example 26. The method according to Example 25, further comprising:

[0300] Obtaining contract information of the first terminal device;

[0301] According to the contract information of the first terminal device, it is determined that a PDU session with an associated relationship can be established for the first terminal device.

[0302] Example 27. The method according to any one of Examples 22 to 26, further comprising:

[0303] Sending a fourth message to the third network device, where the fourth message is used to request information about the network device serving the second PDU session;

[0304] An identification of the second network device is received from the third network device.

[0305] Example 28. The method according to any one of Examples 22 to 27, further comprising:

[0306] A fifth message is sent to the second network device, where the fifth message is used to request establishment of a first PDU session with an associated relationship for the first terminal device.

[0307] Example 29. According to the method described in Example 28, the fifth message also includes an identifier of the second terminal device and an identifier of the second PDU session, which is used to indicate that an association relationship is established between the first PDU session and the first PDU session.

[0308] Example 30. The method according to any one of Examples 22 to 29, further comprising:

[0309] Store association relationship information, where the association relationship information is used to indicate the association relationship between the first PDU session and the second PDU session.

[0310] Example 31. The method according to any one of Examples 22 to 30, further comprising:

[0311] receiving a sixth message, where the sixth message is used to request establishment of a second PDU session for the second terminal device, the sixth message including a first parameter, where the first parameter is used to indicate that the second PDU session requested to be established by the second terminal device is a PDU session with an associated relationship;

[0312] Selecting the second network device that supports the PDU session having the associated relationship;

[0313] A seventh message is sent to the second network device, where the seventh message is used to request establishment of a second PDU session with an associated relationship for the second terminal device.

[0314] Example 32. The method according to Example 31, further comprising:

[0315] An eighth message is sent to the second terminal device, where the eighth message includes information for accepting establishment of the second PDU session.

[0316] Embodiment 33. A communication method, applied to a second network device, comprising:

[0317] receiving a fifth message from the first network device, the fifth message being used to request establishment of a first PDU session having an associated relationship for the first terminal device, the fifth message also including an identifier of the second terminal device and an identifier of a second PDU session, the second PDU session being a PDU session of the second terminal device, and the fifth message being used to indicate establishment of an associated relationship between the first PDU session and the second PDU session;

[0318] Send a message to the first terminal device for accepting the establishment of the first PDU session.

[0319] Example 34. The method according to Example 33, further comprising:

[0320] According to the contract information of the first terminal device, it is determined that the first terminal device supports establishing a PDU session with an associated relationship.

[0321] Example 35. According to the method described in Example 33 or 34, the message for accepting the establishment of the first PDU session includes a second parameter, and the second parameter is used to indicate the manner in which the PDU session performs data processing, and the manner in which the data processing is performed includes transferring business data between the first PDU session and the second PDU session, or transmitting business data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

[0322] Example 36. The method according to any one of Examples 33 to 35, further comprising:

[0323] The same IP address as that of the second PDU session is allocated to the first PDU session.

[0324] Example 37. The method according to any one of Examples 33 to 36, further comprising:

[0325] A seventh message is received from the first network device, where the seventh message is used to request establishment of a second PDU session with an associated relationship for the second terminal device.

[0326] Embodiment 38. The method according to embodiment 37, further comprising:

[0327] A second parameter is sent to the second terminal device, where the second parameter is used to indicate a manner in which the PDU session performs data processing, where the manner in which the data processing is performed includes transferring service data between the first PDU session and the second PDU session, or transmitting service data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

[0328] Example 39. According to the method described in any one of Examples 33 to 38, the fifth message includes a first parameter, and the first parameter is used to indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship.

[0329] Example 40. The method according to any one of Examples 33 to 39, further comprising:

[0330] Sending a ninth message to the fourth network device, where the ninth message is used to request establishment of an N4 session and allocation of a first tunnel, where the first tunnel is associated with the first QoS flow;

[0331] sending a tenth message to the fourth network device, where the tenth message is used to modify the N4 session and allocate a second tunnel, where the second tunnel is associated with the first QoS flow, and the tenth message further indicates transferring data between different terminal devices through the first tunnel and the second tunnel, or sending the same data to different terminal devices;

[0332] The N4 session is associated with the first PDU session and the second PDU session, the first QoS flow is associated with the first PDU session and the second PDU session, and the first QoS flow is used to transmit the data flow of the first service.

[0333] Example 41. The method according to any one of Examples 33 to 39, further comprising:

[0334] Sending a ninth message to the fourth network device, where the ninth message is used to request establishment of an N4 session and allocation of a first tunnel, where the first tunnel is associated with the first QoS flow;

[0335] sending a tenth message to the fourth network device, where the tenth message is used to modify the N4 session and allocate a second tunnel, where the second tunnel is associated with a second QoS flow, and the tenth message further indicates transferring data between different terminal devices through the first QoS flow and the second QoS flow, or sending the same data to different terminal devices;

[0336] The N4 session is associated with the first PDU session and the second PDU session, the first QoS flow is associated with the second PDU session, the second QoS flow is associated with the first PDU session, and the first QoS flow and the second QoS flow are used to transmit data flows of the first service.

[0337] Embodiment 42. The method according to embodiment 40 or 41, further comprising:

[0338] Send second indication information to the fourth network device, where the second indication information is used to indicate that the access network tunnel corresponding to the first QoS flow is set to the first tunnel or the second tunnel, or to indicate that the access network tunnel corresponding to the first QoS flow is the first tunnel and the second tunnel.

[0339] Embodiment 43. The method according to embodiment 40 or 41, further comprising:

[0340] Send second indication information to the fourth network device, where the second indication information is used to indicate that the data flow of the first service is transmitted through the first QoS flow or the second QoS flow, or that the data flow of the first service is transmitted through the first QoS flow and the second QoS flow.

[0341] Example 44. According to the method described in any one of Examples 40 to 43, the ninth message is also used to indicate the activation of the TCP proxy function.

[0342] Example 45. The method according to any one of Examples 40 to 44, further comprising:

[0343] receiving parameters of a first service;

[0344] A first processing mode is received, wherein:

[0345] The first processing manner is to transfer the data of the first service between the first PDU session and the second PDU session, or to transmit the data of the first service on the first PDU session and the second PDU session; or

[0346] The first processing manner is to transfer the data of the first service between the first terminal device and the second terminal device, or to transmit the data of the first service between the first terminal device and the second terminal device.

[0347] Example 46. The method according to any one of Examples 40, 42 to 45, further comprising:

[0348] The first QoS flow is configured for the first terminal device, where the first QoS flow is used to transmit the data flow of the first service.

[0349] Example 47. The method according to any one of Examples 41 to 45, further comprising:

[0350] The first QoS flow is configured for the first terminal device. The first QoS flow is different from the second QoS flow. The first QoS flow and the second QoS flow are used to transmit data flows of the first service.

[0351] Embodiment 48. A communication method, applied to a fourth network device, comprising:

[0352] receiving a ninth message from the second network device, wherein the ninth message is used to request establishment of an N4 session and allocation of a first tunnel, wherein the first tunnel is associated with a first QoS flow, the N4 session is associated with a second PDU session, the first QoS flow is associated with the second PDU session, and the first QoS flow is used to transmit a data flow of a first service;

[0353] A tenth message is received from the second network device, wherein the tenth message is used to modify the N4 session and allocate a second tunnel, wherein:

[0354] The second tunnel is associated with the first QoS flow, and the tenth message further indicates that data is transferred between different terminal devices through the first tunnel and the second tunnel, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, and the first QoS flow is also associated with the first PDU session; or,

[0355] The second tunnel is associated with the second QoS flow, and the tenth message also indicates that data is transferred between different terminal devices through the first QoS flow and the second QoS flow, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, the first QoS flow is associated with the second PDU session, and the second QoS flow is associated with the first PDU session, and the first QoS flow and the second QoS flow are used to transmit the data flow of the first service.

[0356] Embodiment 49. According to the method described in embodiment 48, the ninth message is also used to indicate activation of the TCP proxy function.

[0357] Embodiment 50. The method according to embodiment 49, further comprising:

[0358] activating the TCP proxy function for the second terminal device, where the TCP proxy function is applicable to all services of the second terminal device; or,

[0359] Activate the TCP proxy function for the first service.

[0360] Example 51. The method according to any one of Examples 47 to 49, further comprising:

[0361] Second indication information is received from the second network device, where the second indication information is used to indicate that the access network tunnel corresponding to the first QoS flow is set to the first tunnel or the second tunnel, or to indicate that the access network tunnel corresponding to the first QoS flow is the first tunnel and the second tunnel.

[0362] Example 52. The method according to any one of Examples 47 to 49, further comprising:

[0363] Second indication information is received from the second network device, where the second indication information is used to instruct that the data flow of the first service be transmitted through the first QoS flow or the second QoS flow, or that the data flow of the first service be transmitted through the first QoS flow and the second QoS flow.

[0364] Embodiment 53. A communication method, comprising:

[0365] The first network device receives a first message, where the first message is used to request establishment of a first PDU session for the first terminal device, the first message also including an identifier of the second terminal device and an identifier of a second PDU session, where the second PDU session is a PDU session of the second terminal device;

[0366] The first network device selects a second network device for the first PDU session according to the identifier of the second terminal device and the identifier of the second PDU session, and sends a fifth message to the second network device, where the second network device is a network device serving the second PDU session, and the fifth message is used to request establishment of the first PDU session with an associated relationship for the first terminal device, and the fifth message also includes the identifier of the second terminal device and the identifier of the second PDU session, and the fifth message is used to instruct establishment of an associated relationship between the first PDU session and the second PDU session;

[0367] The second network device sends a ninth message to the fourth network device, where the ninth message is used to request establishment of an N4 session and allocation of a first tunnel, where the first tunnel is associated with a first QoS flow, the N4 session is associated with a second PDU session, the first QoS flow is associated with the second PDU session, and the first QoS flow is used to transmit a data flow of a first service;

[0368] The second network device sends a message to the first terminal device for accepting the establishment of the first PDU session.

[0369] Embodiment 54. The method according to embodiment 53, further comprising:

[0370] The second network device sends a tenth message to the fourth network device, where the tenth message is used to modify the N4 session and allocate a second tunnel, wherein:

[0371] The second tunnel is associated with the first QoS flow, and the tenth message further indicates that data is transferred between different terminal devices through the first tunnel and the second tunnel, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, and the first QoS flow is also associated with the first PDU session; or,

[0372] The second tunnel is associated with the second QoS flow, and the tenth message also indicates that data is transferred between different terminal devices through the first QoS flow and the second QoS flow, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, the first QoS flow is associated with the second PDU session, and the second QoS flow is associated with the first PDU session, and the first QoS flow and the second QoS flow are used to transmit the data flow of the first service.

[0373] Embodiment 55. A communication device comprising:

[0374] a sending unit, configured to send a first message, where the first message is used to request establishment of a first PDU session for the communication device, the first message also including an identifier of a second terminal device and an identifier of a second PDU session, where the second PDU session is a PDU session of the second terminal device, and the identifier of the second terminal device and the identifier of the second PDU session are used by the first network device to select a second network device or to establish an association relationship between the first PDU session and the second PDU session;

[0375] The receiving unit is configured to receive a second message from the first network device, where the second message includes information for accepting the establishment of the first PDU session.

[0376] Embodiment 56. The communication device according to embodiment 55, wherein the first message further includes a session establishment request message, wherein:

[0377] The identifier of the second terminal device and the identifier of the second PDU session are included in the session establishment request message; or,

[0378] The identifier of the second terminal device and the identifier of the second PDU session are included in the first message but are not included in the session establishment request message; or,

[0379] The identifier of the second terminal device and the identifier of the second PDU session are included in the session establishment request message, and are included in the bearer space in the first message except the session establishment request message.

[0380] Example 57. According to the communication device according to Example 55 or 56, the first message includes a first parameter, and the first parameter is used to indicate that the first PDU session requested to be established by the communication device is a PDU session with an associated relationship.

[0381] Example 58. According to the communication device according to any one of Examples 55 to 57, the second message also includes a second parameter, and the second parameter is used to indicate the manner in which the PDU session performs data processing, and the manner in which the data processing is performed includes transferring business data between the first PDU session and the second PDU session, or transmitting business data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

[0382] Example 59. According to the communication device according to any one of Examples 55 to 58, the receiving unit is further used to receive the identifier of the second terminal device and the identifier of the second PDU session from the second terminal device.

[0383] Example 60. According to the communication device according to any one of Examples 55 to 59, the receiving unit is also used to receive information of a first service from the second terminal device, the first service being a service to be transferred from the second terminal device to a target terminal device, and the target terminal device includes the communication device, or includes the second terminal device and the communication device.

[0384] Example 61. According to the communication device according to any one of Examples 55 to 60, the receiving unit is further used to receive connection parameters from the second terminal device, and the connection parameters include slice information and / or data network name DNN corresponding to the second PDU session.

[0385] Embodiment 62. According to the communication device according to any one of Embodiments 55 to 61, the second message includes QoS flow information configured by the second network device for the communication device for transmitting the first service.

[0386] Example 63. According to the communication device according to any one of Examples 55 to 62, the receiving unit is further used to receive a third message from the first network device, and the third message includes QoS flow information configured by the second network device for the communication device for transmitting the first service.

[0387] Example 64. In the communication apparatus according to Example 62 or 63, the QoS flow information includes an identifier of the QoS flow, and the identifier of the QoS flow is the same as or different from the identifier of the QoS flow for transmitting the first service by the second terminal device.

[0388] Example 65. According to the communication device according to any one of Examples 55 to 64, the sending unit is also used to send information of the first service to the second network device, and the information of the first service includes an identifier of the first service and / or packet information for describing the data flow of the first service.

[0389] Embodiment 66. The communication device according to embodiment 65,

[0390] The sending unit is further configured to send the first processing method to the second network device, wherein:

[0391] The first processing manner is to transfer the data of the first service between the first PDU session and the second PDU session, or to transmit the data of the first service on the first PDU session and the second PDU session; or,

[0392] The first processing manner is to transfer the data of the first service between the communication device and the second terminal device, or to transmit the data of the first service between the communication device and the second terminal device.

[0393] Example 67. According to the communication device according to any one of Examples 55 to 66, the sending unit is also used to send a first indication message to the second terminal device, and the first indication message is used to indicate that the first PDU session is established and / or to trigger the data processing process of the PDU session.

[0394] Embodiment 68. A communication device comprising:

[0395] a sending unit, configured to send a sixth message to the first network device, where the sixth message is used to request establishment of a second PDU session for the second terminal device, where the sixth message includes a first parameter, where the first parameter is used to indicate that the second PDU session requested by the communication device to be established is a PDU session with an associated relationship and / or is used to select a second network device;

[0396] A receiving unit is used to receive an eighth message from the first network device, where the eighth message includes information for accepting the establishment of the second PDU session.

[0397] Example 69. According to the communication device described in Example 68, the eighth message also includes a second parameter, and the second parameter is used to indicate the way in which the PDU session performs data processing. The way of performing the data processing includes transferring business data between the second PDU session and the PDU session of other terminal devices, or transmitting business data on the second PDU session and the PDU session of the other terminal device, and the PDU session of the other terminal device has an associated relationship with the second PDU session, wherein the data processing can be performed between the PDU sessions with the associated relationship.

[0398] Example 70. According to the communication device of Example 68 or 69, the sending unit is further used to send the identifier of the communication device and the identifier of the second PDU session to the first terminal device.

[0399] Example 71. According to the communication device according to any one of Examples 68 to 70, the sending unit is also used to send information of a first service to the first terminal device, where the first service is a service to be transferred from the communication device to a target terminal device, and the target terminal device includes the first terminal device, or includes the communication device and the first terminal device.

[0400] Example 72. According to the communication device according to any one of Examples 68 to 71, the sending unit is also used to send connection parameters to the first terminal device, and the connection parameters include slice information and / or data network name DNN corresponding to the second PDU session.

[0401] Example 73. According to the communication device according to any one of Examples 68 to 72, the sending unit is also used to send information of the first service to the second network device, and the information of the first service includes an identifier of the first service and / or packet information for describing the data flow of the first service.

[0402] Embodiment 74. The communication device according to embodiment 73,

[0403] The sending unit is further configured to send the first processing method to the second network device, wherein:

[0404] The first processing manner is to transfer the data of the first service between the PDU session of the other terminal device and the second PDU session, or to transmit the data of the first service on the PDU session of the other terminal device and the second PDU session; or

[0405] The first processing manner is transferring the data of the first service between the first terminal device and the communication apparatus, or transmitting the data of the first service between the first terminal device and the communication apparatus;

[0406] Among them, the PDU session of the other terminal device is associated with the second PDU session.

[0407] Example 75. According to the communication device described in Example 73 or 74, the receiving unit is also used to receive first indication information from the first terminal device before the sending unit sends information of the first service to the second network device, and the first indication information is used to indicate that the first PDU session is established and / or to trigger the data processing process of the PDU session.

[0408] Embodiment 76. A communication device comprising:

[0409] a receiving unit, configured to receive a first message, wherein the first message is used to request establishment of a first PDU session for a first terminal device, the first message further including an identifier of a second terminal device and an identifier of a second PDU session, the second PDU session being a PDU session of the second terminal device;

[0410] A processing unit is used to select a second network device for the first PDU session based on the identifier of the second terminal device and the identifier of the second PDU session, where the second network device is a network device serving the second PDU session.

[0411] Example 77. According to the communication device of Example 76, the communication device also includes a sending unit for sending a second message to the first terminal device, and the second message includes information for accepting the establishment of the first PDU session.

[0412] Example 78. According to the communication device of Example 76 or 77, the first message includes a first parameter, and the first parameter is used to indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship.

[0413] Example 79. According to any one of Examples 76 to 78, the communication device further includes a sending unit for sending a second parameter to the first terminal device, wherein the second parameter is used to indicate a manner in which the PDU session performs data processing, and the manner in which the data processing is performed includes transferring business data between the first PDU session and the second PDU session, or transmitting business data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

[0414] Embodiment 80. The communication device according to embodiment 79, wherein the processing unit is further configured to:

[0415] Obtaining contract information of the first terminal device;

[0416] According to the contract information of the first terminal device, it is determined that a PDU session with an associated relationship can be established for the first terminal device.

[0417] Embodiment 81. The communication device according to any one of embodiments 76 to 80, further comprising a sending unit;

[0418] The sending unit is configured to send a fourth message to the third network device, where the fourth message is used to request information of the network device serving the second PDU session;

[0419] The receiving unit is further configured to receive an identifier of the second network device from the third network device.

[0420] Example 82. According to any one of Examples 76 to 81, the communication device further includes a sending unit for sending a fifth message to the second network device, wherein the fifth message is used to request establishment of a first PDU session with an associated relationship for the first terminal device.

[0421] Example 83. According to the communication device of Example 82, the fifth message also includes the identifier of the second terminal device and the identifier of the second PDU session, which is used to indicate that an association relationship is established between the first PDU session and the first PDU session.

[0422] Example 84. According to the communication device according to any one of Examples 76 to 83, the processing unit is further used to store association relationship information, and the association relationship information is used to indicate the association relationship between the first PDU session and the second PDU session.

[0423] Embodiment 85. The communication device according to any one of embodiments 76 to 84, further comprising a sending unit;

[0424] The receiving unit is further configured to receive a sixth message, where the sixth message is used to request establishment of a second PDU session for the second terminal device, the sixth message including a first parameter, where the first parameter is used to indicate that the second PDU session requested to be established by the second terminal device is a PDU session with an associated relationship;

[0425] The processing unit is further configured to select the second network device that supports the PDU session having the associated relationship;

[0426] The sending unit is used to send a seventh message to the second network device, where the seventh message is used to request establishment of a second PDU session with an associated relationship for the second terminal device.

[0427] Example 86. According to the communication device of Example 85, the communication device also includes a sending unit for sending an eighth message to the second terminal device, and the eighth message includes information for accepting the establishment of the second PDU session.

[0428] Embodiment 87. A communication device comprising:

[0429] a receiving unit, configured to receive a fifth message from the first network device, the fifth message being used to request establishment of a first PDU session having an associated relationship for the first terminal device, the fifth message also including an identifier of the second terminal device and an identifier of a second PDU session, the second PDU session being a PDU session of the second terminal device, and the fifth message being used to indicate establishment of an association relationship between the first PDU session and the second PDU session;

[0430] A sending unit is used to send a message to the first terminal device for accepting the establishment of the first PDU session.

[0431] Example 88. According to the communication device described in Example 87, the communication device also includes a processing unit for determining, based on the contract information of the first terminal device, that the first terminal device supports establishing a PDU session with an associated relationship.

[0432] Example 89. According to the communication device of Example 87 or 88, the message for accepting the establishment of the first PDU session includes a second parameter, and the second parameter is used to indicate the manner in which the PDU session performs data processing, and the manner in which the data processing is performed includes transferring business data between the first PDU session and the second PDU session, or transmitting business data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

[0433] Example 90. According to any one of Examples 87 to 89, the communication device further includes a processing unit for assigning the same IP address as the second PDU session to the first PDU session.

[0434] Example 91. According to the communication device according to any one of Examples 87 to 90, the receiving unit is further used to receive a seventh message from the first network device, and the seventh message is used to request to establish a second PDU session with an associated relationship for the second terminal device.

[0435] Example 92. According to the communication device described in Example 91, the sending unit is further used to send a second parameter to the second terminal device, and the second parameter is used to indicate a manner in which the PDU session performs data processing, and the manner in which the data processing is performed includes transferring business data between the first PDU session and the second PDU session, or transmitting business data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

[0436] Example 93. According to the communication device according to any one of Examples 87 to 92, the fifth message includes a first parameter, and the first parameter is used to indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship.

[0437] Embodiment 94. The communication device according to any one of Embodiments 87 to 93, wherein the sending unit is further configured to:

[0438] Sending a ninth message to the fourth network device, where the ninth message is used to request establishment of an N4 session and allocation of a first tunnel, where the first tunnel is associated with the first QoS flow;

[0439] sending a tenth message to the fourth network device, where the tenth message is used to modify the N4 session and allocate a second tunnel, where the second tunnel is associated with the first QoS flow, and the tenth message further indicates transferring data between different terminal devices through the first tunnel and the second tunnel, or sending the same data to different terminal devices;

[0440] The N4 session is associated with the first PDU session and the second PDU session, the first QoS flow is associated with the first PDU session and the second PDU session, and the first QoS flow is used to transmit the data flow of the first service.

[0441] Embodiment 95. The communication device according to any one of Embodiments 87 to 93, wherein the sending unit is further configured to:

[0442] Sending a ninth message to the fourth network device, where the ninth message is used to request establishment of an N4 session and allocation of a first tunnel, where the first tunnel is associated with the first QoS flow;

[0443] sending a tenth message to the fourth network device, where the tenth message is used to modify the N4 session and allocate a second tunnel, where the second tunnel is associated with a second QoS flow, and the tenth message further indicates transferring data between different terminal devices through the first QoS flow and the second QoS flow, or sending the same data to different terminal devices;

[0444] The N4 session is associated with the first PDU session and the second PDU session, the first QoS flow is associated with the second PDU session, the second QoS flow is associated with the first PDU session, and the first QoS flow and the second QoS flow are used to transmit data flows of the first service.

[0445] Example 96. According to the communication device of Example 94 or 95, the sending unit is further used to send second indication information to the fourth network device, and the second indication information is used to indicate that the access network tunnel corresponding to the first QoS flow is set to the first tunnel or the second tunnel, or to indicate that the access network tunnel corresponding to the first QoS flow is the first tunnel and the second tunnel.

[0446] Example 97. According to the communication device of Example 94 or 95, the sending unit is further used to send second indication information to the fourth network device, and the second indication information is used to indicate that the data flow of the first service is transmitted through the first QoS flow or the second QoS flow, or that the data flow of the first service is transmitted through the first QoS flow and the second QoS flow.

[0447] Example 98. According to the communication device according to any one of Examples 94 to 97, the ninth message is also used to indicate the activation of the TCP proxy function.

[0448] Embodiment 99. The communication device according to any one of Embodiments 94 to 98, wherein the receiving unit is further configured to:

[0449] receiving parameters of a first service;

[0450] A first processing mode is received, wherein:

[0451] The first processing manner is to transfer the data of the first service between the first PDU session and the second PDU session, or to transmit the data of the first service on the first PDU session and the second PDU session; or

[0452] The first processing manner is to transfer the data of the first service between the first terminal device and the second terminal device, or to transmit the data of the first service between the first terminal device and the second terminal device.

[0453] Example 100. According to the communication device according to any one of Examples 94, 96 to 99, the communication device also includes a processing unit for configuring the first QoS flow for the first terminal device, and the first QoS flow is used to transmit the data flow of the first service.

[0454] Example 101. According to any one of Examples 95 to 99, the communication device further includes a processing unit for configuring the first QoS flow for the first terminal device, the first QoS flow is different from the second QoS flow, and the first QoS flow and the second QoS flow are used to transmit data flows of the first service.

[0455] Embodiment 102. A communication device comprising:

[0456] a receiving unit, configured to receive a ninth message from a second network device, the ninth message being used to request establishment of an N4 session and allocation of a first tunnel, the first tunnel being associated with a first QoS flow, the N4 session being associated with a second PDU session, the first QoS flow being associated with the second PDU session, and the first QoS flow being used to transmit a data flow of a first service;

[0457] The receiving unit is further configured to receive a tenth message from the second network device, wherein the tenth message is used to modify the N4 session and allocate a second tunnel, wherein:

[0458] The second tunnel is associated with the first QoS flow, and the tenth message further indicates that data is transferred between different terminal devices through the first tunnel and the second tunnel, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, and the first QoS flow is also associated with the first PDU session; or,

[0459] The second tunnel is associated with the second QoS flow, and the tenth message also indicates that data is transferred between different terminal devices through the first QoS flow and the second QoS flow, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, the first QoS flow is associated with the second PDU session, and the second QoS flow is associated with the first PDU session, and the first QoS flow and the second QoS flow are used to transmit the data flow of the first service.

[0460] Embodiment 103. According to the communication device described in embodiment 102, the ninth message is also used to indicate the activation of the TCP proxy function.

[0461] Embodiment 104. The communication device according to embodiment 103 further comprises a processing unit configured to activate the TCP proxy function for the second terminal device, wherein the TCP proxy function is applicable to all services of the second terminal device; or

[0462] Activate the TCP proxy function for the first service.

[0463] Example 105. According to the communication device according to any one of Examples 101 to 103, the receiving unit is further used to receive second indication information from the second network device, and the second indication information is used to indicate that the access network tunnel corresponding to the first QoS flow is set to the first tunnel or the second tunnel, or to indicate that the access network tunnel corresponding to the first QoS flow is the first tunnel and the second tunnel.

[0464] Example 106. According to the communication device according to any one of Examples 101 to 103, the receiving unit is further used to receive second indication information from the second network device, and the second indication information is used to indicate that the data flow of the first service is transmitted through the first QoS flow or the second QoS flow, or that the data flow of the first service is transmitted through the first QoS flow and the second QoS flow.

[0465] Embodiment 107. A communication system comprising a first network device, a second network device, and a fourth network device, wherein:

[0466] The first network device is configured to receive a first message, where the first message is used to request establishment of a first PDU session for a first terminal device, the first message also including an identifier of a second terminal device and an identifier of a second PDU session, where the second PDU session is a PDU session of the second terminal device;

[0467] The first network device is further configured to select the second network device for the first PDU session according to the identifier of the second terminal device and the identifier of the second PDU session, and send a fifth message to the second network device, where the second network device is a network device serving the second PDU session, and the fifth message is used to request establishment of the first PDU session with an associated relationship for the first terminal device, the fifth message also including the identifier of the second terminal device and the identifier of the second PDU session, and the fifth message is used to instruct establishment of an association relationship between the first PDU session and the second PDU session;

[0468] The second network device is configured to send a ninth message to the fourth network device, where the ninth message is used to request establishment of an N4 session and allocation of a first tunnel, where the first tunnel is associated with a first QoS flow, the N4 session is associated with a second PDU session, the first QoS flow is associated with the second PDU session, and the first QoS flow is used to transmit a data flow of a first service;

[0469] The second network device is further used to send a message to the first terminal device for accepting the establishment of the first PDU session.

[0470] Embodiment 108. The communication system according to embodiment 107,

[0471] The second network device is further configured to send a tenth message to the fourth network device, where the tenth message is used to modify the N4 session and allocate a second tunnel, wherein:

[0472] The second tunnel is associated with the first QoS flow, and the tenth message further indicates that data is transferred between different terminal devices through the first tunnel and the second tunnel, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, and the first QoS flow is also associated with the first PDU session; or,

[0473] The second tunnel is associated with the second QoS flow, and the tenth message also indicates that data is transferred between different terminal devices through the first QoS flow and the second QoS flow, or the same data is sent to different terminal devices, wherein the N4 session is also associated with the first PDU session, the first QoS flow is associated with the second PDU session, and the second QoS flow is associated with the first PDU session, and the first QoS flow and the second QoS flow are used to transmit the data flow of the first service.

[0474] Embodiment 109. A device comprising a unit for performing the method described in any embodiment of the present application.

[0475] Example 110. A computer program product, comprising a computer program, which, when running on a computer, enables the computer to execute the method described in any one of Examples 1 to 13, or enables the computer to execute the method described in any one of Examples 14 to 21, or enables the computer to execute the method described in any one of Examples 22 to 32, or enables the computer to execute the method described in any one of Examples 33 to 47, or enables the computer to execute the method described in any one of Examples 48 to 52, or enables the computer to execute the method described in any one of Examples 53 to 54.

Claims

1. A communication method, characterized in that: Applied to a first terminal device, the method includes: Sending a first message, where the first message is used to request establishment of a first PDU session for the first terminal device, the first message also including an identifier of the second terminal device and an identifier of the second PDU session, where the second PDU session is a PDU session of the second terminal device, and the identifier of the second terminal device and the identifier of the second PDU session are used by the first network device to select a second network device or to establish an association relationship between the first PDU session and the second PDU session, wherein service data can be transferred between the first PDU session and the second PDU session having the association relationship; receiving a second message from the first network device, the second message including information for accepting establishment of the first PDU session; The method further includes receiving an identifier of the second terminal device and an identifier of the second PDU session from the second terminal device.

2. The method according to claim 1, characterized in that The first message also includes a session establishment request message, wherein: The identifier of the second terminal device and the identifier of the second PDU session are included in the session establishment request message; or, The identifier of the second terminal device and the identifier of the second PDU session are included in the first message but are not included in the session establishment request message; or, The identifier of the second terminal device and the identifier of the second PDU session are included in the session establishment request message, and are included in the bearer space in the first message except the session establishment request message.

3. The method according to claim 1 or 2, characterized in that The first message includes a first parameter, and the first parameter is used to indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship.

4. The method according to claim 1 or 2, characterized in that The second message also includes a second parameter, which is used to indicate the manner in which the PDU session performs data processing. The manner in which the data processing is performed includes transferring business data between the first PDU session and the second PDU session, or transmitting business data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

5. The method according to claim 1 or 2, characterized in that The method further comprises: Information of a first service is received from the second terminal device, where the first service is a service to be transferred from the second terminal device to a target terminal device, where the target terminal device includes the first terminal device, or includes the second terminal device and the first terminal device.

6. The method according to claim 1 or 2, characterized in that The method further comprises: Receive connection parameters from the second terminal device, where the connection parameters include slice information and / or data network name DNN corresponding to the second PDU session.

7. The method according to claim 1 or 2, characterized in that The second message includes QoS flow information configured by the second network device for the first terminal device for transmitting the first service.

8. The method according to claim 1 or 2, characterized in that The method further comprises: A third message is received from the first network device, where the third message includes QoS flow information configured by the second network device for the first terminal device to transmit the first service.

9. The method according to claim 7, characterized in that The QoS flow information includes an identifier of the QoS flow, and the identifier of the QoS flow is the same as or different from the identifier of the QoS flow used by the second terminal device to transmit the first service.

10. The method according to claim 1 or 2, characterized in that The method further comprises: Sending information of the first service to the second network device, where the information of the first service includes an identifier of the first service and / or packet information for describing a data flow of the first service.

11. The method according to claim 10, characterized in that The method further comprises: Sending a first processing method to the second network device, wherein: The first processing manner is to transfer the data of the first service between the first PDU session and the second PDU session, or to transmit the data of the first service on the first PDU session and the second PDU session; or, The first processing manner is to transfer the data of the first service between the first terminal device and the second terminal device, or to transmit the data of the first service between the first terminal device and the second terminal device.

12. The method according to any one of claims 1, 2, 9 and 11, characterized in that: The method further comprises: Send a first indication message to the second terminal device, where the first indication message is used to indicate that the first PDU session has been established and / or to trigger the data processing process of the PDU session.

13. A communication method, characterized in that: Applied to a first network device, the method includes: Receive a first message, where the first message is used to request establishment of a first PDU session for a first terminal device, the first message also including an identifier of a second terminal device and an identifier of a second PDU session, where the second PDU session is a PDU session of the second terminal device; According to the identifier of the second terminal device and the identifier of the second PDU session, a second network device is selected for the first PDU session, and the second network device is a network device serving the second PDU session, wherein the first message includes a first parameter, and the first parameter is used to indicate that the first PDU session requested to be established by the first terminal device is a PDU session with an associated relationship, and business data can be transferred between PDU sessions with the associated relationship.

14. The method according to claim 13, characterized in that The method further comprises: A second message is sent to the first terminal device, where the second message includes information for accepting establishment of the first PDU session.

15. The method according to claim 13 or 14, characterized in that The method further comprises: A second parameter is sent to the first terminal device, where the second parameter is used to indicate a manner in which the PDU session performs data processing, where the manner in which the data processing is performed includes transferring service data between the first PDU session and the second PDU session, or transmitting service data on the first PDU session and the second PDU session, wherein the data processing can be performed between PDU sessions with an associated relationship.

16. The method according to claim 15, characterized in that The method further comprises: Obtaining contract information of the first terminal device; According to the contract information of the first terminal device, it is determined that a PDU session with an associated relationship can be established for the first terminal device.

17. The method according to claim 13 or 14, characterized in that The method further comprises: Sending a fourth message to the third network device, where the fourth message is used to request information about the network device serving the second PDU session; An identification of the second network device is received from the third network device.

18. The method according to any one of claims 13, 14 and 16, characterized in that: The method further comprises: A fifth message is sent to the second network device, where the fifth message is used to request establishment of a first PDU session with an associated relationship for the first terminal device.

19. The method according to claim 18, characterized in that The fifth message also includes the identifier of the second terminal device and the identifier of the second PDU session, which is used to indicate that an association relationship is established between the first PDU session and the first PDU session.

20. The method according to any one of claims 13, 14, 16 and 19, characterized in that: The method further comprises: Store association relationship information, where the association relationship information is used to indicate the association relationship between the first PDU session and the second PDU session.

21. The method according to any one of claims 13, 14, 16 and 19, characterized in that: The method further comprises: receiving a sixth message, where the sixth message is used to request establishment of a second PDU session for the second terminal device, the sixth message including a first parameter, where the first parameter is used to indicate that the second PDU session requested to be established by the second terminal device is a PDU session with an associated relationship; Selecting the second network device that supports the PDU session having the associated relationship; A seventh message is sent to the second network device, where the seventh message is used to request establishment of a second PDU session with an associated relationship for the second terminal device.

22. The method according to claim 21, characterized in that The method further comprises: An eighth message is sent to the second terminal device, where the eighth message includes information for accepting establishment of the second PDU session.

23. A communication device, characterized in that: The communication device comprises a processor and a memory; the memory is used to store one or more computer programs, and the one or more computer programs include computer execution instructions. When the communication device is running, the processor executes the one or more computer programs stored in the memory, so that the communication device performs the method according to any one of claims 1 to 12, or performs the method according to any one of claims 13 to 22.

24. A computer-readable storage medium, characterized in that The computer-readable storage medium is used to store a computer program. When the computer program is run on a computer, the computer is caused to execute the method according to any one of claims 1 to 12, or the method according to any one of claims 13 to 22.

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