A method, apparatus, and system for data transmission

Abstract

Embodiments of the present application provide a method, device and system for data transmission, the method comprising: receiving, by a session management network element, a join request message from a terminal device through a first PDU session, the join request message being used to request to join a multicast service; and if the first PDU session is in a deactivated state, sending, by the session management network element, first information to a first access network device, the first information being used to activate part of QoS flows in associated QoS flows of the first PDU session, the part of QoS flows being used to transmit data of the multicast service. Since part of QoS flows in associated QoS flows of the first PDU session is activated, it is avoided to activate all QoS flows of the first PDU session, which helps to reduce resource waste, and can more reasonably utilize air interface resources while ensuring normal transmission of data of the multicast service.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to a method, apparatus, and system for data transmission. Background Technology

[0002] To conserve network resources, the 3rd Generation Partnership Project (3GPP) protocol standard proposed unicast-based multicast technology. Simply put, unicast-based multicast technology means that terminal devices request to join multicast services via unicast. When the access network equipment supports multicast, user plane network elements and access network equipment can send multicast session data to different terminal devices within the group via multicast.

[0003] In unicast-based multicast technology, how to make reasonable use of air interface resources is a problem worthy of attention. Summary of the Invention

[0004] This application provides a method, apparatus, and system for data transmission, which helps to make more rational use of air interface resources.

[0005] In a first aspect, a method for data transmission is provided, which can be executed by a session management network element, or by a component (e.g., a circuit, a chip, or a chip system) configured in the session management network element, without limitation in this application.

[0006] The method includes: receiving a join request message from a terminal device through a first protocol data unit (PDU) session, the join request message being used to request to join a multicast service; if the first PDU session is in a deactivated state, sending first information to a first access network device, the first information being used to activate a portion of the QoS stream in the associated quality of service (QoS) stream of the first PDU session, the portion of the QoS stream being used to transmit the data of the multicast service.

[0007] Based on the above scheme, after receiving the join request message from the terminal device through the first PDU session requesting to join the multicast service, the session management network element determines the state of the first PDU session. When the first PDU session is in the deactivated state, the session management network element sends the first information to the first access network device. By sending the first information, the first access network device is triggered to activate a portion of the QoS stream in the associated QoS stream of the first PDU session. This portion of the QoS stream is used to transmit the data of the multicast service. This achieves the activation of this portion of the QoS stream to transmit the multicast service data, thereby avoiding the activation of all QoS streams in the associated QoS stream of the first PDU session. This helps to reduce resource waste and makes more reasonable use of air interface resources while ensuring the normal transmission of multicast service data.

[0008] On the other hand, the solution of this application supports the session management network element to trigger the first access network device to activate part of the QoS flow in the associated QoS flow of the first PDU session, making the QoS management of the session management network element more flexible.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the first information includes the identification information of the portion of the QoS flow.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, sending the first information to the first access network device includes: sending the first information to the first access network device if the multicast session associated with the multicast service is in an active state; and / or sending the first information to the first access network device if the multicast session associated with the multicast service changes from a deactivated state to an active state.

[0011] Based on the above scheme, when the first PDU session is in an inactive state, the session management network element will also determine the state of the multicast session associated with the multicast service, and thus determine the timing of sending the first information based on the state of the multicast session. This method avoids triggering the first access network device to activate this part of the QoS flow when the multicast session is in an inactive state; this part of the QoS flow is used to transmit the multicast service data. In other words, it helps reduce resource waste and makes more rational use of air interface resources while ensuring the normal transmission of multicast service data.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: receiving second information, the second information being used to notify that the multicast session is activated; if the multicast session is in a deactivated state, determining, based on the second information, that the multicast session changes from a deactivated state to an activated state.

[0013] Based on the above scheme, the session management network element can receive notification messages about the status of the multicast session, thereby determining the status of the multicast session and, further, determining the timing for sending the first message. This helps to make more rational use of air interface resources.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: sending third information to the terminal device; wherein the third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session; or, the third information is used to indicate that not all associated QoS flows of the first PDU session are in an active state.

[0015] Based on the above scheme, the session management network element can notify the terminal device of the activated QoS flows in the associated QoS flows of the first PDU session, or indicate to the terminal device that not all associated QoS flows of the first PDU session are in an active state. In this way, the terminal device can obtain whether all associated QoS flows of the first PDU session are in an active state.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: if a service request message is received from the terminal device, and the service request message is used to request the transmission of unicast service data through the first PDU session, then a fourth message is sent to the first access network device, the fourth message being used to activate a second QoS stream; wherein the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit the unicast service data; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

[0017] Based on the above scheme, if a service request message is received from a terminal device, the session management network element can trigger the first access network device to activate the second QoS stream by sending a fourth message. This second QoS stream can be used by the first access network device to transmit unicast services. This method ensures the transmission of unicast services while preventing the second QoS stream from being repeatedly activated, thus improving system communication efficiency.

[0018] In conjunction with the first aspect, in some implementations of the first aspect, the method is applied to a scenario where the terminal device moves from the first access network device to the second access network device. The method further includes: if the path switching request message or the PDU session context update request message does not include first indication information, the first indication information being used to indicate that the second access network device supports multicast / broadcast services, then sending fifth information to the second access network device, the fifth information being used to activate a third QoS flow, the third QoS flow being an associated QoS flow of the first PDU session and being in a deactivated state; or, if the second access network device does not support multicast / broadcast services, then sending the fifth information to the second access network device.

[0019] Based on the above scheme, if the second access network device does not support multicast / broadcast services, the session management network element can trigger the second access network device to activate the third QoS flow by sending the fifth information. This third QoS flow can be used by the second access network device to transmit data via unicast. This method allows the second access network device to establish a context for unicast data transmission in advance. When subsequent services arrive, there is no need to interact with the core network device for control signaling, which helps to ensure service continuity to a certain extent.

[0020] Secondly, a method for data transmission is provided, which can be executed by a terminal device or by a component of the terminal device (such as a chip or circuit), and this application does not limit the scope of the method.

[0021] The method includes: obtaining the status of a first Protocol Data Unit (PDU) session and the status of the associated QoS flows of the first PDU session; if the first PDU session is active and not all associated QoS flows of the first PDU session are active, then sending a service request message to the core network device, the service request message being used to request the transmission of unicast service data through the first PDU session; and / or, if the first PDU session is active and all QoS flows in the associated QoS flows of the first PDU session are active, then not sending the service request message.

[0022] Based on the above scheme, when a terminal device has a unicast service transmission requirement, it can determine whether to send a service request message based on the current PDU session status and the status of the associated QoS streams of the PDU session. If the first PDU session is active and not all associated QoS streams of the first PDU session are active, the terminal device sends a service request message. And / or, if the first PDU session is active and all associated QoS streams of the first PDU session are active, no service request message is sent. This approach helps reduce resource waste and allows for more rational use of air interface resources while ensuring normal data transmission for unicast services.

[0023] In conjunction with the second aspect, in some implementations of the second aspect, the aforementioned acquisition of the status of the associated QoS flows of the first PDU session includes: receiving third information; wherein the third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session; or, the third information is used to indicate that not all associated QoS flows of the first PDU session are in an active state.

[0024] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: sending a join request message through the first PDU session, the join request message being used to request to join the multicast service.

[0025] Thirdly, a data method is provided, which can be executed by a first access network device, or by a component of the first access network device (e.g., a chip or circuit), and this application does not limit this.

[0026] The method includes: receiving first information, the first information being used to activate a portion of the QoS stream in the associated QoS stream of a first PDU session, the portion of the QoS stream being used to transmit data for multicast services; and activating the portion of the QoS stream according to the first information.

[0027] Based on the above scheme, if the session management network element sends the first information to the first access network device, the first access network device can activate a portion of the QoS flow in the associated QoS flow of the first PDU session according to the first information. This portion of the QoS flow is used to transmit the multicast service, thereby realizing the activation of this portion of the QoS flow for transmitting multicast service data. This avoids activating all the QoS flows of the first PDU session, which helps to reduce resource waste and makes more reasonable use of air interface resources while ensuring the normal transmission of multicast service data.

[0028] In conjunction with the third aspect, in some implementations of the third aspect, the method further includes: receiving fourth information, the fourth information being used to activate a second QoS stream; activating the second QoS stream according to the fourth information; wherein the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit data for unicast services; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

[0029] Based on the above scheme, if a service request message is received from a terminal device, the session management network element can trigger the first access network device to activate the second QoS stream by sending a fourth message. This second QoS stream can be used by the first access network device to transmit unicast services. This method ensures the transmission of unicast services while preventing the second QoS stream from being repeatedly activated, thus improving the reliability and efficiency of system communication.

[0030] Fourthly, a data transmission method is provided, comprising: a session management network element receiving a join request message from a terminal device through a first protocol data unit (PDU) session, the join request message being used to request to join a multicast service; if the first PDU session is in a deactivated state, the session management network element sending first information to a first access network device, the first information being used to activate a portion of the QoS stream in the associated QoS stream of the first PDU session, the portion of the QoS stream being used to transmit data of the multicast service; and the first access network device activating the portion of the QoS stream according to the first information.

[0031] In conjunction with the fourth aspect, in some implementations of the fourth aspect, the method further includes: if a service request message is received from the terminal device, the service request message being used to request the transmission of unicast service data through the first PDU session, then the session management network element sends fourth information to the first access network device, the fourth information being used to activate the second QoS flow; the first access network device activates the second QoS flow according to the fourth information;

[0032] Wherein, the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit the unicast service; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

[0033] In conjunction with the fourth aspect, in some implementations of the fourth aspect, the method further includes: if the path switching request message or the PDU session context update request message does not include the first indication information, the first indication information being used to indicate that the second access network device supports multicast / broadcast services, then the session management network element sends the fifth information to the second access network device; or, if the second access network device does not support multicast / broadcast services, then the session management network element sends the fifth information to the second access network device; the second access network device activates the third QoS flow according to the fifth information; wherein the fifth information is used to activate the third QoS flow, the third QoS flow being an associated QoS flow of the first PDU session and being in a deactivated state.

[0034] Fifthly, a data transmission apparatus is provided for performing the methods provided in the first, second, or third aspects described above. Specifically, the apparatus may include units and / or modules for performing the methods provided in the first aspect, or any of the above-described implementations of the first aspect, or the second aspect, or any of the above-described implementations of the second aspect, or the third aspect, such as processing units and / or communication units.

[0035] In one implementation, the device is a session management network element. When the device is a session management network element, the communication unit can be a transceiver, or an input / output interface; the processing unit can be at least one processor. Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0036] In another implementation, the device is a chip, chip system, or circuit used in a session management network element. When the device is a chip, chip system, or circuit used in a session management network element, the communication unit can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; the processing unit can be at least one processor, processing circuit, or logic circuit.

[0037] In one implementation, the device is a terminal device. When the device is a terminal device, the communication unit can be a transceiver or an input / output interface; the processing unit can be at least one processor. Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0038] In another implementation, the device is a chip, chip system, or circuit used in a terminal device. When the device is a chip, chip system, or circuit used in a terminal device, the communication unit may be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; the processing unit may be at least one processor, processing circuit, or logic circuit.

[0039] A sixth aspect provides a communication device comprising: a memory for storing a program; and at least one processor for executing the computer program or instructions stored in the memory to perform the method provided by the first aspect, or any of the above-described implementations of the first aspect, or the second aspect, or any of the above-described implementations of the second aspect, or the third aspect, or any of the above-described implementations of the third aspect.

[0040] In a seventh aspect, this application provides a processor for performing the methods provided in the foregoing aspects.

[0041] Unless otherwise specified, or if it does not contradict its actual function or internal logic in the relevant description, the transmission and acquisition / reception operations involved in the processor can be understood as processor output and reception, input and other operations, or as transmission and reception operations performed by radio frequency circuits and antennas. This application does not limit them in this regard.

[0042] Eighthly, a computer-readable storage medium is provided that stores program code for execution by a device, the program code including a method for performing the first aspect, or any of the above-described implementations of the first aspect, or the second aspect, or any of the above-described implementations of the second aspect, or the third aspect, or any of the above-described implementations of the third aspect.

[0043] Ninth aspect, a computer program product containing instructions is provided, which, when run on a computer, causes the computer to perform the method provided by the first aspect, or any of the above-described implementations of the first aspect, or the second aspect, or any of the above-described implementations of the second aspect, or the third aspect, or any of the above-described implementations of the third aspect.

[0044] In a tenth aspect, a chip is provided, the chip including a processor and a communication interface, the processor reading instructions stored in a memory through the communication interface, and executing the method provided by the first aspect, or any of the above-described implementations of the first aspect, or the second aspect, or any of the above-described implementations of the second aspect, or the third aspect, or any of the above-described implementations of the third aspect.

[0045] Optionally, as one implementation, the chip further includes a memory storing computer programs or instructions. The processor is used to execute the computer programs or instructions stored in the memory. When the computer programs or instructions are executed, the processor is used to execute the method provided by the first aspect, or any of the above-described implementations of the first aspect, or the second aspect, or any of the above-described implementations of the second aspect, or the third aspect.

[0046] Eleventhly, a communication system is provided, including the session management network element and the first access network device mentioned above.

[0047] Optionally, the communication system also includes the second access network device described above. Attached Figure Description

[0048] Figure 1 A schematic diagram of a network architecture is shown.

[0049] Figure 2 A schematic diagram of a network architecture for MBS is shown.

[0050] Figure 3 A schematic diagram of a multicast technology based on unicast is shown.

[0051] Figure 4 A schematic diagram of a data transmission method 200 provided in an embodiment of this application is shown.

[0052] Figure 5A schematic diagram of another data transmission method 300 provided in an embodiment of this application is shown.

[0053] Figure 6 A schematic diagram of another data transmission method 400 provided in an embodiment of this application is shown.

[0054] Figure 7 This illustration shows a schematic diagram of a data transmission apparatus 700 provided in an embodiment of this application.

[0055] Figure 8 A schematic diagram of a data transmission apparatus 800 provided in an embodiment of this application is shown. Detailed Implementation

[0056] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0057] The technical solutions of this application can be applied to various communication systems, such as: Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD) system, Universal Mobile Telecommunication System (UMTS), 5th Generation (5G) system, or New Radio (NR) or other evolved communication systems.

[0058] The technical solutions provided in this application can also be applied to future communication systems, such as the sixth-generation mobile communication system, and this application does not limit them.

[0059] The technical solutions provided in this application can also be applied to machine-type communication (MTC), long-term evolution-machine (LTE-M) technology, device-to-device (D2D) networks, machine-to-machine (M2M) networks, Internet of Things (IoT) networks, or other networks. Among these, IoT networks may include, for example, vehicle-to-everything (V2X) networks. The communication methods in V2X systems are collectively referred to as vehicle-to-X (V2X), where X can represent anything. For example, V2X may include vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, or vehicle-to-network (V2N) communication, etc.

[0060] As an example, Figure 1 A schematic diagram of a network architecture is shown. (For example...) Figure 1As shown, this network architecture uses the 5G system (5GS) as an example. This network architecture may include, but is not limited to: network slice selection function (NSSF), authentication server function (AUSF), unified data management (UDM), network exposure function (NEF), network repository function (NRF), policy control function (PCF), application function (AF), access and mobility management function (AMF), session management function (SMF), user equipment (UE), radio access network equipment, user plane function (UPF), and data network (DN).

[0061] Where DN can be the Internet; NSSF, AUSF, UDM, NEF, NRF, PCF, AF, AMF, SMF, and UPF are network elements in the core network, because Figure 1 Taking a 5G system as an example, the core network can be called the 5G core network (5GC or 5GCN).

[0062] The following is about Figure 1 A brief introduction to each network element shown in the diagram is provided.

[0063] 1. UE: can be called terminal equipment, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user equipment.

[0064] Terminal devices can be devices that provide voice / data to users, such as handheld devices with wireless connectivity, in-vehicle devices, etc. Currently, examples of terminals include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving vehicles, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, wearable devices, terminal devices in 5G networks, or future public land mobile communication networks. Terminal devices in a network (PLMN), etc., are not limited to this in the embodiments of this application.

[0065] By way of example and not limitation, in this embodiment, the terminal device can also be a wearable device. Wearable devices, also known as wearable smart devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables, such as glasses, gloves, watches, clothing, and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothing or accessories. Wearable devices are not merely hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are feature-rich, large in size, and can achieve complete or partial functions without relying on a smartphone, such as smartwatches or smart glasses, as well as those that focus on a specific type of application function and require the use of other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0066] Furthermore, in this embodiment, the terminal device can also be a terminal device in an IoT system. IoT is an important component of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection.

[0067] It should be noted that terminal devices and access network devices can communicate with each other using some air interface technology (such as NR or LTE). Terminal devices can also communicate with each other using some air interface technology (such as NR or LTE).

[0068] In this embodiment, the device for implementing the functions of the terminal device can be the terminal device itself, or it can be a device that supports the terminal device in implementing the functions, such as a chip system or a chip. This device can be installed in the terminal device. In this embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0069] 2. Radio Access Network (RAN) Equipment: This equipment provides access to a communication network for authorized users in a specific area. Specifically, it can include wireless network equipment in 3GPP (3rd Generation Partnership Project) networks or access points in non-3GPP networks. For ease of description, RAN equipment will be used in the following text.

[0070] AN devices can employ different radio access technologies. Currently, there are two types of radio access technologies: 3GPP access technologies (e.g., those used in 3rd generation (3G), 4th generation (4G), or 5G systems) and non-3GPP access technologies. 3GPP access technologies refer to access technologies that conform to 3GPP standards and specifications. For example, access network equipment in a 5G system is called a next-generation NodeBase station (gNB) or RAN equipment. Non-3GPP access technologies can include air interface technologies such as access points (APs) in Wireless Fidelity (WiFi), Worldwide Interoperability for Microwave Access (WiMAX), and Code Division Multiple Access (CDMA). AN devices can allow terminal devices and the 3GPP core network to interconnect using non-3GPP technologies.

[0071] The AN device is responsible for functions such as radio resource management, quality of service (QoS) management, data compression, and encryption on the air interface side. The AN device provides access services to terminal devices, thereby completing the forwarding of control signals and user data between the terminal devices and the core network.

[0072] AN devices may include, but are not limited to: macro base stations, micro base stations (also known as small stations), radio network controllers (RNCs), Node Bs (NBs), base station controllers (BSCs), base transceiver stations (BTSs), home base stations (e.g., home-evolved Node Bs, or home Node Bs (HNBs)), baseband units (BBUs), access points (APs), wireless relay nodes, wireless backhaul nodes, transmission points (TPs), or transmission and reception points (TRPs) in WiFi systems. They may also be gNBs or transmission points (TRPs or TPs) in 5G (e.g., NR) systems, one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or network nodes constituting gNBs or transmission points, such as distributed units (DUs), or base stations in next-generation 6G communication systems. This application does not limit the specific technology or device form used in the AN devices.

[0073] 3. AMF: Primarily used for access control, mobility management, attach and detach functions.

[0074] 4. SMF: Primarily used for user plane network element selection, user plane network element redirection, Internet Protocol (IP) address allocation for terminal devices, as well as session establishment, modification, release, and QoS control. The session management function network element is also known as the session management network element.

[0075] 5. UPF: Primarily used for receiving and forwarding user plane data. For example, a UPF can receive user plane data from a DN and send it to the terminal device via an AN device. A UPF can also receive user plane data from the terminal device via an AN device and forward it to the DN. User plane function network elements are also known as user plane network elements.

[0076] 6. NEF: Primarily used to securely expose services and capabilities provided by 3GPP network functions to the outside world.

[0077] 7. PCF: Primarily used as a unified policy framework to guide network behavior, providing policy rule information to control plane network elements (such as AMF, SMF, etc.).

[0078] 8. AF: Primarily used to provide services to 3GPP networks, such as interacting with PCF for policy control.

[0079] 9. NSSF: Primarily used for network slice selection.

[0080] 10. UDM: Primarily used for UE subscription data management, including UE identifier storage and management, UE access authorization, etc.

[0081] 11. DN: Primarily used by operators to provide data services to UEs. Examples include the Internet, third-party service networks, and IP Multimedia Service (IMS) networks.

[0082] 12. AUSF: Primarily used for user authentication, etc.

[0083] 13. NRF: Primarily used to store network functional entities and their descriptions of the services they provide.

[0084] exist Figure 1 In the network architecture shown, network elements can communicate with each other via interfaces. For example, the terminal connects to the AMF via the N1 interface, the RAN connects to the AMF via the N2 interface, the RAN connects to the UPF via the N3 interface, the UPF connects to the SMF via the N4 interface, and the AMF connects to the SMF via the N11 interface.

[0085] It should be noted that, Figure 1 The names of the various network elements and communication interfaces involved are given as examples based on current protocols, but this does not limit the embodiments of this application to only known communication systems. Therefore, the standard names that appear when describing the current protocols are functional descriptions. This application does not limit the specific names of network elements, interfaces, or signaling, but only indicates the function of the network element, interface, or signaling, which can be extended to other systems, such as 2G, 3G, 4G, or future communication systems.

[0086] It should be understood that the above Figure 1 The network architecture shown is merely an example, and the network architecture applicable to the embodiments of this application is not limited to this. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiments of this application.

[0087] It should also be understood that Figure 1The AMF, SMF, UPF, PCF, NSSF, AUSF, UDM, etc. shown can be understood as network elements in the core network used to implement different functions, such as network slices that can be combined as needed. These core network elements can be independent devices or integrated into the same device to implement different functions. This application does not limit the specific form of the above network elements.

[0088] Figure 2 A network architecture for multicast / broadcast service (MBS) is illustrated. This architecture is based on... Figure 1 Based on the illustrated architecture, extensions are made, for example, by adding two functional entities: a multicast / broadcast session management function (MB-SMF) and a multicast / broadcast user plane function (MB-UPF), to support multicast / broadcast services or functions. The UPF is further divided into an intermediate-UPF (I-UPF) and an anchor-UPF (A-UPF). The I-UPF connects to the access network (RAN), while the A-UPF is the session anchor UPF, also known as the PDU session anchor (PSA), which connects to the remote DN.

[0089] exist Figure 2 In this application, the MB-SMF implements the control plane functions of the MBS, responsible for managing multicast / broadcast services / groups / sessions. The MB-SMF can connect to the MBS server, multicast / broadcast service function (MBSF) network element, or network exposure function (NEF) network element to receive information related to multicast / broadcast services (e.g., MBS description information). Furthermore, the MB-SMF can connect to the PCF to create resources for multicast / broadcast services. The MBU-UPF can be used to transmit MBS data. Optionally, the MB-SMF can be integrated into the PCF or SMF as a functional module, the MB-UPF can be integrated into the UPF as a functional module, or the MB-SMF and MB-UPF can be deployed separately; this application does not limit this.

[0090] It should be noted that the name MB-SMF or MB-UPF mentioned above is an example. In 5G networks, MB-SMF or MB-UPF can also be other names, and this application does not limit them.

[0091] To facilitate understanding of the embodiments of this application, the terms involved in this application will be briefly explained first.

[0092] 1. Protocol Data Unit (PDU) Session: The 5G core network (5GC) supports PDU connection services. PDU connection services refer to the exchange of PDU data packets between a terminal device and the DN (Digital Data Center). PDU connection services are established by the terminal device initiating the establishment of a PDU session. Once a PDU session is established, a data transmission channel between the terminal device and the DN is established. In other words, the PDU session is at the UE (User Equipment) level. Each terminal device can establish one or more PDU sessions.

[0093] As mentioned earlier, the SMF (Session Management Function) is primarily responsible for session management in the mobile network. PDU sessions can be established, modified, or released between the terminal device and the SMF via NAS (Session Management, SM) signaling.

[0094] In this embodiment of the application, a PDU session can be identified by a PDU session identifier (PDU sessionidentifier, PDU session ID).

[0095] 2. PDU Session Activation and Deactivation: This is a new state characteristic of PDU sessions introduced in 5G. Specifically, when a terminal device enters idle mode, for established PDU sessions' user plane connections, it can selectively activate the user plane connection of a particular session, i.e., delete the air interface resources and N3 tunnel connection of that session, while maintaining the signaling connections between network elements such as AMF, SMF, and PCF. When the UE exits idle mode or subsequently, through a selective activation process, the terminal device can initiate activation for a specific session as needed, without having to activate all session resources.

[0096] 3. MBS: Also known as multicast / broadcast service or multicast / broadcast communication service, it includes multicast and broadcast services. MBS is an application-level concept, such as security alert service and map update service.

[0097] 4. Multicast / broadcast session: also known as MBS session, multicast / broadcast communication session, or multicast / broadcast service session, which includes multicast sessions and broadcast sessions.

[0098] Multiple terminal devices receiving the same multicast service can belong to a multicast group. A multicast group can be a transport layer concept (i.e., a transport group). In this case, a UE can send a request to join the multicast group, or in other words, join a multicast session or multicast service, before it can receive the multicast service. A multicast group can also be an application layer concept (i.e., a subscribed group). In this case, only UEs belonging to the multicast group can receive the multicast service. Broadcast services do not involve specific group management.

[0099] 5. QoS Flow: The granularity of QoS differentiation within a PDU session. A QoS Flow Identifier (QFI) can be used to identify a QoS flow. A PDU session can include multiple QoS flows, each with a different QFI. In other words, a QFI can be unique within a PDU session.

[0100] To save network resources, the 3rd Generation Partnership Project (3GPP) protocol standard proposed a multicast technology based on unicast. Figure 3 A schematic diagram of a multicast technology based on unicast is shown. (For example...) Figure 3 As shown, unicast-based multicast technology refers to terminal devices requesting to join a multicast group via unicast. Access network devices and core network devices maintain the unicast bearer for the terminal devices. When sending multicast services, content providers (e.g., application servers (AS)) can send data to user plane network elements via multicast. For example, the multicast service data can be data packets with a destination IP address that is a multicast address, i.e., multicast data packets transmitted using multicast. Alternatively, the content provider can also send data via unicast. For example, the multicast service data can be data packets with a destination IP address that is the address of a core network device (e.g., MB-SMF). If the access network device supports multicast, user plane network elements and access network devices can send data to terminal devices via multicast.

[0101] In unicast-based multicast technology, how to make reasonable use of air interface resources is a problem worthy of attention.

[0102] It is understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0103] The terminology used in this application has been briefly explained above, and will not be repeated in the following embodiments. The data transmission method provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings. The embodiments provided in this application can be applied to the above... Figure 1 The network architecture shown is not limited.

[0104] Figure 4 A schematic diagram of a data transmission method 200 provided in an embodiment of this application is shown. Method 200 may include the following steps.

[0105] S210, the terminal device sends a join request message to the session management network element through the first PDU session.

[0106] Accordingly, the session management network element receives the join request message through the first PDU session.

[0107] The join request message is used to request to join a multicast service. In other words, it requests to join a multicast session associated with a multicast service, or a multicast group associated with a multicast service. Specifically, the join request message may include the identification information of the multicast service.

[0108] The service identification information for multicast services can be the identifier of the multicast service, such as one or more of the following: the identifier of the multicast / broadcast service, the name of the multicast / broadcast service, the multicast / broadcast address of the multicast / broadcast service, the multicast / broadcast IP address of the multicast / broadcast service, the temporary mobile group identity (TMGI) corresponding to the multicast / broadcast service, the session address of the multicast / broadcast service, the identifier of the multicast session, the identifier of the multicast group, etc.

[0109] Furthermore, the join request message may include identification information of the first PDU session. Specifically, the join request message may be a non-access stratum (NAS) message such as a PDU session modification request message or a PDU session establishment request message. The identification information of the first PDU session can be used to identify the first PDU session, for example, a PDU session ID.

[0110] Sending or receiving join request messages through the first PDU session can be understood as sending or receiving join request messages through the control plane of the first PDU session.

[0111] It should be noted that sending or receiving a join request message through the first PDU session can be replaced with sending or receiving a join request message that includes the identifier of the first PDU session.

[0112] S220, if the first PDU session is in a deactivated state, the session management network element sends the first information to the first access network device.

[0113] Accordingly, the first access network device receives the first information.

[0114] Specifically, the first information can be used to activate a portion of the QoS stream in the associated QoS stream of the first PDU session, which is used to transmit multicast service data. Specifically, the first information can be the QoS information of this portion of the QoS stream, for example, including the QFI and QoS parameters of this portion of the QoS stream.

[0115] The first PDU session is in a deactivated state, which can be understood as: the user plane connection of the first PDU session is deleted. For example, the air interface resources of the first PDU session and the N3 tunnel connection of the first PDU session are deleted, or the context about the first PDU session stored in the first access network device is deleted.

[0116] It should be noted that when the first PDU session is in a deactivated state, its control plane can still perform signaling interaction. Therefore, in step S210, the control plane of the first PDU session can be used to send or receive join request messages.

[0117] The associated QoS flow of the first PDU session can be understood as: the QoS flow included in the first PDU session, the QoS flow belonging to the first PDU session, or the QoS flow in the first PDU session.

[0118] It should be understood that the associated QoS streams of the first PDU session may include multiple (two or more) QoS streams, all of which are unicast QoS streams. The QoS streams used for transmitting multicast service data within these multiple QoS streams can be referred to as partial QoS streams. These partial QoS streams can be one or more QoS streams, without limitation. For example, suppose the associated QoS streams of the first PDU session may include four: QoS stream 1, QoS stream 2, QoS stream 3, and QoS stream 4; among these four QoS streams, the QoS streams used for transmitting the aforementioned multicast service data are QoS stream 3 and QoS stream 4. Here, the partial QoS streams refer to QoS stream 3 and QoS stream 4.

[0119] It should be noted that the QoS flows in the associated QoS flows of the first PDU session mentioned above can be simply referred to as the QoS flows in the first PDU session without restriction.

[0120] In addition, some QoS flows can also be referred to as: multicast-related QoS flows, associated QoS flows, or first QoS flows, which are unicast QoS flows corresponding to multicast QoS flows used to transmit data for multicast services.

[0121] In this application, the names "first QoS flow" and "partial QoS flow" can be used interchangeably without restriction.

[0122] Furthermore, in this application, the same term has the same meaning in the context, and will not be repeated hereafter after the explanation given above.

[0123] Specifically, in step S220, the session management network element can determine the QoS flow from the associated QoS flow of the first PDU session in the following way: After receiving the join request message, the session management network element can obtain the QoS information of the multicast service requested to join by the join request message from the multicast / broadcast session management network element, and map the multicast QoS flow of the multicast service to a part of the QoS flow (i.e., the first QoS flow) in the QoS flow associated with the first PDU session. For example, the session management network element can find the part of the QoS flow according to the QoS information corresponding to the multicast QoS flow of the multicast service. The QoS parameters of the part of the QoS flow are the same as the QoS parameters of the multicast QoS flow.

[0124] For example, assuming that the multicast QoS stream of the multicast service includes QoS stream 5 and QoS stream 6, the associated QoS stream of the first PDU session may include four: QoS stream 1, QoS stream 2, QoS stream 3, and QoS stream 4. Among these four QoS streams, QoS stream 3 and QoS stream 5 have the same QoS parameters, and QoS stream 4 and QoS stream 5 have the same QoS parameters. Therefore, the QoS streams used to transmit the data of the above multicast service in the associated QoS streams of the first PDU session refer to QoS stream 3 and QoS stream 4.

[0125] Specifically, mapping the multicast QoS stream of the multicast service to a portion of the QoS stream associated with the first PDU session can refer to establishing a correspondence between the multicast QoS stream and the portion of the QoS stream so that the portion of the QoS stream can be used to transmit the data of the multicast service.

[0126] The QoS information for multicast services may include one or more of the following: the QFI of the multicast QoS stream of the multicast service, the service data flow (SDF) corresponding to the multicast QoS stream, and the QoS parameters corresponding to the QFI of the multicast QoS stream. For example, QoS parameters may include: 5G QoS identifier (5QI) (representing a set of QoS parameters, including bandwidth, latency jitter, etc.), allocation retention priority (ARP), guaranteed bit rate (GBR), maximum bit rate (MBR), QoS notification control (QNC), etc.

[0127] Furthermore, the session management network element sends first information to trigger the first access network device to activate this part of the QoS flow, so that the first access network device can subsequently transmit the multicast service data to the terminal device via unicast.

[0128] It should be noted that a portion of the QoS stream is used to transmit multicast service data; this can be understood as transmitting multicast service data through a portion of the QoS stream. The first information is used to activate the portion of the QoS stream; in other words, the first information is used to trigger the first access network device to restore or establish the context of that portion of the QoS stream.

[0129] S230, the first access network device activates this part of the QoS flow based on the first information.

[0130] Specifically, in step S230, the first access network device activates the QoS flow in this part under the trigger of the first information.

[0131] Activating this portion of the QoS flow can also be understood as: establishing or restoring the context of this portion of the QoS flow; it may also include one or more of the following: allocating air interface resources for this portion of the QoS flow, or storing the QoS information of this portion of the QoS flow. The air interface resources can be a data radio bearer (DRB).

[0132] According to the method provided in the above embodiments, after receiving the join request message for joining the multicast service sent by the terminal device through the first PDU session, the session management network element sends first information to the first access network device when the first PDU session is in an inactive state. By sending the first information, the first access network device is triggered to activate a portion of the QoS stream in the associated QoS stream of the first PDU session. This portion of the QoS stream is used to transmit the data of the multicast service. This realizes the activation of this portion of the QoS stream to transmit the data of the multicast service, thereby avoiding the activation of all QoS streams in the associated QoS stream of the first PDU session, which helps to reduce resource waste and makes more reasonable use of resources while ensuring the normal transmission of multicast service data.

[0133] It should be understood that information exchange between the session management network element and the first access network device is transmitted through the access and mobility management network element.

[0134] In another embodiment of this application, the role of the first information in S220 and S230 can be replaced by all QoS flows in the associated QoS flow used to activate the first PDU session.

[0135] In this embodiment, the first information may be the QoS information of all QoS flows in the associated QoS flow of the first PDU session.

[0136] Specifically, if the first PDU session is in a deactivated state, the session management network element sends first information to the first access network device. The first information is used to activate all QoS flows in the associated QoS flows of the first PDU session. Accordingly, the first access network device activates all QoS flows in the associated QoS flows of the first PDU session according to the first information.

[0137] It should be understood that the specific steps in the above embodiments can be referred to method 200, and will not be repeated here.

[0138] According to the method provided in the above embodiments, after receiving the join request message for joining the multicast service sent by the terminal device through the first PDU session, the session management network element sends first information to the first access network device when the first PDU session is in a deactivated state. By sending the first information, the first access network device is triggered to activate all QoS flows in the associated QoS flows of the first PDU session. In this way, the management of the session management network element has greater flexibility.

[0139] Optionally, step S220 includes: the session management network element sending the first information to the access and mobility management network element, and the access and mobility management network element sending the first information to the first access network device.

[0140] Specifically, the session management network element can send the first information to the access and mobility management network element via an N11 message. As an example, this N11 message can be an N1N2 message transfer message (Namf_communication_N1N2MessageTransfer), which includes an N2 SM container containing the first information. Further, the access and mobility management network element can send this first information to the first access network device via an N2 message, which can be a next-generation application protocol (NGAP) PDU session resource setup request message or an NGAP PDU session resource modify request message, etc.

[0141] It should be understood that both N11 and N2 messages can include identification information of the first PDU session, which may be the first PDU session ID.

[0142] It should be noted that N2 messages can also be special messages, such as the MBS session resource setup request message.

[0143] Optionally, the first information includes the identification information of the portion of the QoS flow. For example, the identification information of the portion of the QoS flow is QFI.

[0144] Specifically, the first information may be the QoS information of the portion of the QoS flow, and the QoS information includes the identification information of the portion of the QoS flow.

[0145] Optionally, the QoS information may also include QoS parameters of the QoS flow, such as ARP, 5QI, GBR, MBR, etc.

[0146] Furthermore, after receiving the first information, the first access network device activates that portion of the QoS flow based on the first information.

[0147] Optionally, in one implementation scenario of the above embodiments, method 200 further includes: the session management network element determining the state of the first PDU session.

[0148] The state of the first PDU session can include an active state and a deactivated state. Specifically, the session management network element can determine the state of the first PDU session based on its context. The context of the first PDU session can be stored in the session management network element or obtained from other network elements, without restriction.

[0149] Specifically, the session management network element can determine the state of the first PDU session based on the context of the first PDU session in the following ways:

[0150] Method 1: The session management network element determines the state of the first PDU session based on the state information in the context of the first PDU session.

[0151] Specifically, the context of the first PDU session includes the status information of the first PDU session, which includes "activated" and "deactivated / inactive / deactive". If the status information is "activated", the session management network element determines that the first PDU session is in an active state; or, if the status information is "deactivated / inactive / deactive", the session management network element determines that the first PDU session is in a deactivated state.

[0152] It should be understood that in this case, the session management network element can receive a first trigger message sent by other network elements, which is used to activate / deactivate the first PDU session, and activate / deactivate the first PDU session according to the first trigger message.

[0153] For example, if the session management network element receives a downlink data notification message sent by the user plane network element, and this downlink data notification message can be used to trigger the activation of the first PDU session, then the session management network element can set the status of the first PDU session to active.

[0154] For example, if the session management network element has received a service request message from the terminal device before S210, and the service request message includes the identification information of the first PDU session, then after S210, the session management network element can set the status of the first PDU session to active.

[0155] Method 2: The session management network element determines the state of the first PDU session by judging whether the context of the first PDU session contains specific information related to the activation state.

[0156] The specific information related to the activation state can be referred to as the first activation state information, which may include the identification information of the N3 channel and / or the N4 configuration information, etc. The session management network element can determine the state of the first PDU session based on whether the context of the first PDU session contains the first activation state information. When the context contains the first activation state information, the session management network element determines that the state of the first PDU session is active; or, when the context does not contain the first activation state information, the session management network element determines that the state of the first PDU session is deactivated.

[0157] Optionally, step S220 includes: if the multicast session associated with the multicast service is in an active state, the session management network element sends first information to the first access network device; and / or, if the multicast session associated with the multicast service changes from a deactivated state to an active state, the session management network element sends first information to the first access network device.

[0158] Among them, the multicast session associated with the multicast service is the multicast session established for transmitting data for the multicast service, or the multicast session for transmitting data for the multicast service, or the multicast session corresponding to the multicast service in the core network.

[0159] Specifically, the session management network element can determine the status of the multicast session associated with the multicast service. If the multicast session is active, the session management network element sends a first message to the first access network device to trigger the first access network device to activate that part of the QoS flow. And / or, if the multicast session is deactivated, the session management network element waits for the multicast session to become active before sending the first message to the first access network device.

[0160] According to the method provided in the above implementation scenario, when the first PDU session is in an inactive state, the session management network element will also determine the state of the multicast session associated with the multicast service and determine the timing of sending the first information based on the state of the multicast session. This method avoids triggering the first access network device to activate that portion of the QoS flow when the multicast session is in an inactive state; this portion of the QoS flow is used to transmit the multicast service data. In other words, it helps reduce resource waste and allows for more rational use of air interface resources while ensuring the normal transmission of multicast service data.

[0161] It should be understood that the context of the first PDU session may also include the status information of the associated QoS flows of the first PDU session, which includes "activated" and "deactivated / inactive / deactive". After S220, the session management network element may update the status information of the aforementioned QoS flows to "activated".

[0162] Optionally, in one implementation scenario of the above embodiments, method 200 further includes: the session management network element determining the status of the multicast session associated with the multicast service.

[0163] The status of a multicast session associated with a multicast service includes an active state and a deactivated state. Specifically, the session management network element can obtain the status of the multicast session from the multicast / broadcast session management network element.

[0164] Specifically, the session management network element can receive second information, which is used to notify that the multicast session is activated. If the multicast session is in a deactivated state, the session management network element determines that the multicast session changes from a deactivated state to an activated state based on the second information.

[0165] In one example, the second information could be a session status indication, which indicates a change in the status of the multicast session.

[0166] Specifically, the session management network element can subscribe to the status information of multicast sessions from the multicast / broadcast session management network element. If the multicast / broadcast session management network element determines that the status of the multicast session has changed based on the context of the multicast session associated with the multicast service, the multicast / broadcast session management network element can send an MBS session context status notification (Nmbsmf_MBSsession_contextstatusnotify) message to the session management network element. The MBS session context status notification message includes second information, which is used to indicate that the status of the multicast session has changed. For example, it indicates that the status of the multicast session changes from a deactivated state to an active state (i.e., the multicast session is activated), or it indicates that the status of the multicast session changes from an active state to a deactivated state (i.e., the multicast session is deactivated).

[0167] Furthermore, when the multicast session is in a deactivated state, the session management network element can determine, based on the second information, that the multicast session is transitioning from a deactivated state to an active state. Alternatively, when the multicast session is in an active state, the session management network element can determine, based on the second information, that the multicast session is transitioning from an active state to a deactivated state.

[0168] It should be noted that the multicast / broadcast session management network element stores the context of the multicast session, which includes the session's status information, such as "active" or "inactive / deactive / deactivated". If the status information is "activated", the multicast / broadcast session management network element determines that the multicast session is active; conversely, if the status information is "deactivated", the multicast / broadcast session management network element determines that the multicast session is deactivated.

[0169] It should be understood that, in this case, the multicast / broadcast session management network element can receive a second trigger message sent by other network elements, which is used to activate the multicast session associated with the multicast service.

[0170] For example, if the multicast / broadcast session management network element receives an MBS session update request (Nmbsmf_MBSsession update_request) message from an application function (AF), and this MBS session update request message is used to request the activation of the multicast session associated with the multicast service, then the multicast / broadcast session management network element can set the status of the multicast session to active.

[0171] It should be understood that when an application sends a message to the multicast / broadcast session management network element, it can send the message directly or send it to other network elements (such as NEF and MBSF network elements) first, and then the other network elements will further send the message to the multicast / broadcast session management network element.

[0172] For example, the multicast / broadcast session management network element can receive N4 notification (N4mbnotification) messages from the multicast / broadcast user plane function network element. These N4 notification messages are used to notify that the multicast session associated with the multicast service has been activated. In this case, the multicast / broadcast session management network element can set the status of the multicast session to active.

[0173] Optionally, in one implementation scenario of the above embodiments, method 200 further includes: the session management network element sending third information to the terminal device, wherein the third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session; or, the third information is used to indicate that not all associated QoS flows of the first PDU session are in an active state.

[0174] Specifically, the session management network element can send third information to the access and mobility management network element via an N11 message. As an example, this N11 message can be an N1N2 message transfer (Namf_communication_N1N2MessageTransfer) message, which includes an N1 SM container containing the third information. Furthermore, the access and mobility management network element can send this third information to the terminal device via a NAS message.

[0175] It should be understood that both the N11 message and the N1 SM container message may include the identification information of the first PDU session, which may be the first PDU session ID.

[0176] It should be understood that both the N11 message and the N1 SM container message may include the identification information of the first PDU session, which may be the first PDU session ID.

[0177] Specifically, this third piece of information can be the PDU session reactivation result information.

[0178] In one alternative implementation, the third information is used to notify the QoS flow that is activated in the associated QoS flow of the first PDU session.

[0179] Specifically, the third information may include the identification information of the activated QoS flow, for example, the identification information of the aforementioned first QoS flow. Furthermore, through this third information, the terminal device can determine which QoS flows are activated among the associated QoS flows of the first PDU session.

[0180] "Activated" can be understood as: in the context of the first PDU session of the session management network element, the QoS flow with the status information "activated" in the associated QoS flow of the first PDU session.

[0181] In another alternative implementation, the third information is used to indicate that the associated QoS flow of the first PDU session is not active.

[0182] For example, the third piece of information is an indication that not all associated QoS flows of the first PDU session are active.

[0183] Specifically, the indication information can be set to different values, one of which can be used to indicate that not all associated QoS flows of the first PDU session are active. For example, if the indication information is 1 bit, a value of 1 indicates that all associated QoS flows of the first PDU session are active, while a value of 0 indicates that not all associated QoS flows of the first PDU session are active.

[0184] According to the method provided in the above implementation scenario, the session management network element can notify the terminal device of the activated QoS flows in the associated QoS flows of the first PDU session, or indicate to the terminal device that not all associated QoS flows of the first PDU session are in an active state. In this way, the terminal device can obtain whether all associated QoS flows of the first PDU session are in an active state.

[0185] Optionally, in one implementation scenario of the above embodiments, if the join request message in S210 is a PDU session modification request message, then the method 200 further includes: the session management network element sending a PDU session modification acceptance message to the terminal device.

[0186] The PDU session modification accept message can be used to respond to the join request message in S210.

[0187] Specifically, the session management network element can send a PDU session modification acceptance message to the access and mobility management network element via an N11 message. As an example, this N11 message can be a PDU session context update response (Nsmf_PDUsession_updateSMcontext response) message, which may include an N1 SM container containing the PDU session modification acceptance message. Furthermore, the access and mobility management network element can send a PDU session modification acceptance message to the terminal device via a NAS message.

[0188] As one implementation method, after S210, the session management network element can send a PDU session modification acceptance message to the terminal device.

[0189] Optionally, in one implementation scenario of the above embodiments, the method 200 further includes: if the session management network element receives a service request message from the terminal device, and the service request message is used to request the transmission of unicast service data through the first PDU session, then the session management network element sends fourth information to the first access network device, the fourth information being used to activate the second QoS flow.

[0190] The second QoS stream is an associated QoS stream of the first PDU session and is used to transmit data of unicast services requested by the terminal device; or the second QoS stream is an associated QoS stream of the first PDU session and is in a deactivated state.

[0191] In one example, the second QoS flow refers to the associated QoS flow belonging to the first PDU session and is used to transmit the QoS flow of unicast service data requested by the terminal device.

[0192] Specifically, the associated QoS flows of the first PDU session may include multiple (two or more) QoS flows, all of which are unicast QoS flows. The QoS flow used to transmit unicast service data among these multiple QoS flows can be designated as the second QoS flow. This second QoS flow can be one or more QoS flows, without limitation. For example, suppose the associated QoS flows of the first PDU session may include four: QoS flow 1, QoS flow 2, QoS flow 3, and QoS flow 4; among these four QoS flows, the QoS flow used to transmit the aforementioned unicast service data is QoS flow 1, and the second QoS flow here refers to QoS flow 1.

[0193] In another example, the second QoS flow refers to the QoS flow that is deactivated in the associated QoS flow of the first PDU session.

[0194] Specifically, the associated QoS flows of the first PDU session may include multiple (two or more) QoS flows, all of which are unicast QoS flows. Among these multiple QoS flows, the QoS flow in the deactivated state can be referred to as the second QoS flow. This second QoS flow can be one or more QoS flows, without restriction. For example, suppose the associated QoS flows of the first PDU session may include four: QoS flow 1, QoS flow 2, QoS flow 3, and QoS flow 4; among these four QoS flows, the active QoS flows are QoS flow 3 and QoS flow 4, and the deactivated QoS flows are QoS flow 1 and QoS flow 2. Here, the second QoS flow refers to QoS flow 1 and QoS flow 2.

[0195] In one alternative implementation, the session management network element receives a service request message from the terminal device. Correspondingly, the terminal device sends a service request message to the session management network element.

[0196] The service request message is used to request the transmission of unicast service data through the first PDU session. Specifically, the service request message may include the service identification information of the unicast service.

[0197] The service identification information of the unicast service can be the identifier of the unicast service, such as the IP address of the unicast service or the service name of the unicast service.

[0198] In addition, the service request message may include identification information of the first PDU session.

[0199] In the above implementation scenario, the method 200 may further include: the first access network device receiving the fourth information and activating the second QoS flow according to the fourth information.

[0200] The fourth piece of information can be the QoS information of the second QoS stream.

[0201] Specifically, the QoS information of the second QoS flow includes the QFI of the second QoS flow.

[0202] Optionally, the QoS information of the second QoS flow may also include the QoS parameters of the second QoS flow, wherein the QoS parameters may include ARP, 5QI, GBR, MBR, etc.

[0203] The activation of the second QoS flow by the first access network device based on the fourth information can also be understood as the establishment or restoration of the context of the second QoS flow by the first access network device based on the fourth information.

[0204] Specifically, activating the second QoS flow includes one or more of the following: allocating air interface resources for the second QoS flow and storing the QoS information of the second QoS flow. The air interface resources may be DRBs (Diagram Files).

[0205] Optionally, the session management network element sends the fourth information to the first access network device, including: the session management network element sending the fourth information to the access and mobility management network element, and the access and mobility management network element sending the fourth information to the first access network device.

[0206] Specifically, the session management network element can send fourth information to the access and mobility management network element via an N11 message. As an example, this N11 message can be an N1N2 message transfer (Namf_communication_N1N2MessageTransfer) message, which includes an N2 SM container, and the N2 SM container includes the fourth information. Furthermore, the access and mobility management network element can send this fourth information to the first access network device via an N2 message; for example, the N2 message can be an NGAP PDU session resource modify request message, etc.

[0207] It should be understood that both N11 and N2 messages can include identification information of the first PDU session, which may be the first PDU session ID.

[0208] According to the method provided in the above implementation scenario, if a service request message is received from a terminal device, the session management network element can also trigger the first access network device to activate the second QoS stream. The second QoS stream can be used by the first access network device to transmit unicast service data. This method helps to improve the reliability of service transmission.

[0209] In the above implementation scenario, the method 200 may further include: the terminal device obtaining the status of the first PDU session and the status of the associated QoS flow of the first PDU session.

[0210] Specifically, the state of the first PDU session can include an active state and a deactivated state. In particular, the terminal device can determine the state of the first PDU session based on its context. The context of the first PDU session can be stored in the terminal device or obtained from other network elements, without restriction.

[0211] Specifically, the terminal device can determine the state of the first PDU session based on the context of the first PDU session in the following ways:

[0212] Method 1: The terminal device determines the state of the first PDU session based on the state information in the context of the first PDU session.

[0213] Specifically, the context of the first PDU session includes the state information of the first PDU session, which includes "activated" and "deactivated / inactive / deactive". If the state information is "activated", the terminal device determines that the state of the first PDU session is active; or, if the state information is "deactivated / inactive / deactive", the terminal device determines that the state of the first PDU session is deactivated.

[0214] It should be understood that, in this scenario, the terminal device can receive a third trigger message sent by the first access network device, which is used to update the state of the first PDU session. Upon receiving this third trigger message, the terminal device can update the state information of the first PDU session accordingly.

[0215] It should be noted that the third trigger message sent by the first access network device can be a direct forwarding of a message from the core network, or it can be generated by the first access network device based on a message from the core network.

[0216] For example, if a terminal device receives a PDU session modification acceptance message, which includes the identification information of the first PDU session, the terminal device will set the status of the first PDU session to active.

[0217] Method 2: The terminal device determines the state of the first PDU session by judging whether the context of the first PDU session contains specific information related to the activation state.

[0218] The specific information related to the activation state can be referred to as the second activation state information. This second activation state information may include the air interface resource information of the first PDU session, such as the configuration information of the Packet Data Convergence Protocol (PDCP). The terminal device can determine the state of the first PDU session based on whether the context of the first PDU session contains the second activation state information. When the context includes the second activation state information, the terminal device determines that the state of the first PDU session is active; otherwise, when the context does not contain the second activation state information, the terminal device determines that the state of the first PDU session is deactivated.

[0219] Optionally, in the above implementation scenario, the method 200 further includes: the terminal device obtaining the status of the associated QoS flow of the first PDU session.

[0220] In one optional implementation, the state of the associated QoS flows of the first PDU session includes whether all associated QoS flows of the first PDU session are active or not. The terminal device can determine whether all associated QoS flows of the first PDU session are active by using third information.

[0221] For example, if the third information is used to indicate that not all associated QoS flows of the first PDU session are active, the terminal device can determine that not all associated QoS flows of the first PDU session are active based on the indication of the third information.

[0222] For example, if the third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session, the terminal device can know which QoS flows in the associated QoS flows of the first PDU session are activated based on the QFI of the activated QoS flows in the third information, and thus determine that not all of the first PDU sessions are in an active state.

[0223] In another alternative implementation, the state of the associated QoS flow of the first PDU session includes an active state and a deactivated state.

[0224] Specifically, the terminal device can determine the status of the associated QoS flow of the first PDU session based on the context of the first PDU session. The context of the first PDU session includes the status information of the associated QoS flow, and there is a one-to-one correspondence between the associated QoS flow and its status information. The context of the first PDU session can be stored in the terminal device or obtained from other network elements, without restriction.

[0225] Specifically, the associated QoS flows of the first PDU session include one or more QoS flows, any one of which is denoted as QoS flow X. The context of the first PDU session includes the correspondence between QoS flow X and its status information, which includes "activated" and "deactivated / inactive / deactive". If the status information of QoS flow X is "activated", the terminal device determines that the status of QoS flow X is active; or, if the status information of QoS flow X is "deactivated / inactive / deactive", the terminal device determines that the status of QoS flow X is deactivated.

[0226] It should be understood that in this case, the terminal device can receive a notification message sent by the first access network device. This notification message is used to notify the status of the associated QoS flow of the first PDU session. The terminal device can update the status information of the associated QoS flow of the first PDU session according to the notification message.

[0227] For example, the notification message can be the aforementioned third information. Specifically, the third information is used to notify the activated QoS flow in the associated QoS flow of the first PDU session. The third information may include the QFI of the activated first QoS flow, so that the terminal device sets the state of the first QoS flow to the active state according to the third information.

[0228] In one example, if the first PDU session is active and not all associated QoS flows of the first PDU session are active, the terminal device sends a service request message to the session management network element. This service request message is used to request the transmission of unicast service data through the first PDU session.

[0229] Specifically, assuming a terminal device needs to transmit unicast services through a first PDU session, if the first PDU session is active and not all associated QoS flows of the first PDU session are active, the terminal device can send a service request message. Furthermore, the session management network element can trigger the first access network device to activate a second QoS flow based on this service request message, allowing the terminal device to transmit the unicast service data through the second QoS flow.

[0230] In another example, if the first PDU session is active and all associated QoS streams of the first PDU session are active, the terminal device determines that the associated QoS streams of the first PDU session can be used to transmit unicast service data. Therefore, the terminal device will transmit the unicast service data through the associated QoS streams of the first PDU session. In other words, the terminal device does not send a service request message.

[0231] According to the method provided in the above implementation scenario, when a terminal device has a unicast service transmission requirement, the terminal device can also determine whether to send a service request message based on the current PDU session status and the status of the associated QoS flow of the PDU session. If the terminal device sends a service request message, the session management network element can send second information to the first access network device to activate the second QoS flow. Alternatively, if the terminal device does not send a service request message, the session management network element can refrain from sending the second information, thereby avoiding the activation of the second QoS flow. This method ensures both the data transmission of unicast services and prevents the second QoS flow from being repeatedly activated, thus improving system communication efficiency.

[0232] Optionally, in another implementation scenario of the above embodiments, the method can be applied when a terminal device moves from a first access network device to a second access network device, and the method 200 further includes:

[0233] If the path switching request message or the PDU session context update request message does not include the first indication information, which is used to indicate that the second access network device supports multicast / broadcast services, then the session management network element sends the fifth information to the second access network device; or, if the second access network device does not support multicast / broadcast services, then the session management network element sends the fifth information to the second access network device.

[0234] The fifth piece of information is used to activate the third QoS flow, which is an associated QoS flow of the first PDU session and is in a deactivated state.

[0235] Specifically, the associated QoS flows of the first PDU session may include multiple (two or more) QoS flows, all of which are unicast QoS flows. Among these multiple QoS flows, the QoS flow in the deactivated state can be referred to as the third QoS flow. This third QoS flow can be one or more QoS flows, without restriction. For example, suppose the associated QoS flows of the first PDU session may include four: QoS flow 1, QoS flow 2, QoS flow 3, and QoS flow 4; among these four QoS flows, the active QoS flows are QoS flow 3 and QoS flow 4, and the deactivated QoS flows are QoS flow 1 and QoS flow 2. Here, the third QoS flow refers to QoS flow 1 and QoS flow 2.

[0236] In the above implementation scenario, the method may further include: the second access network device receiving the fifth information and activating the third QoS flow based on the fifth information.

[0237] The fifth piece of information can be the QoS information of the third QoS stream.

[0238] Specifically, the QoS information of the third QoS stream includes the QFI of the third QoS stream.

[0239] Optionally, the QoS information of the third QoS flow may also include the QoS parameters of the third QoS flow, wherein the QoS parameters may include ARP, 5QI, GBR, MBR, etc.

[0240] The second access network device activating the third QoS flow based on the fifth information can be understood as the second access network device establishing the context of the third QoS flow based on the fifth information.

[0241] Specifically, activating the third QoS flow includes one or more of the following: allocating air interface resources for the second QoS flow and storing the QoS information of the second QoS flow. The air interface resources may be DRBs (Diagram Files).

[0242] Optionally, the session management network element sends the fifth information to the second access network device, including: the session management network element sending the fifth information to the access and mobility management network element, and the access and mobility management network element sending the fifth information to the second access network device.

[0243] Specifically, the session management network element can send the fifth information to the access and mobility management network element via an N11 message. As an example, this N11 message can be an N1N2 message transfer (Namf_Communication_N1N2MessageTransfer) message, which includes an N2 SM container, and the N2 SM container includes the fifth information. Furthermore, the access and mobility management network element can send this fifth information to a second access network device via an N2 message; for example, the N2 message can be an NGAP PDU session resource modify request message, etc.

[0244] It should be understood that both N11 and N2 messages can include identification information of the first PDU session, which may be the first PDU session ID.

[0245] Optionally, in the above implementation scenario, the first access network device can be a device that supports multicast / broadcast services or a device that does not support multicast / broadcast services.

[0246] According to the method provided in the above implementation scenario, if the second access network device does not support multicast / broadcast services, the session management network element can also trigger the second access network device to activate the third QoS flow by sending the fifth information. The third QoS flow can be used by the second access network device to transmit data in unicast mode. Through this method, the second access network device can establish a context for data transmission in unicast mode in advance. When subsequent services arrive, there is no need to interact with the core network device for control signaling, which helps to ensure the continuity of services to a certain extent.

[0247] Optionally, in the above implementation scenario, the method may further include: the session management network element obtaining multicast capability information of the second access network device, the multicast capability information including whether the second access network device supports multicast / broadcast services.

[0248] Specifically, if a terminal device switches from a first access network device to a second access network device, the session management network element can receive an N2 path switch request or a path switch request message from the second access network device, and can also receive a PDU session context update request message from the AMF. If the N2 path switch request, path switch message, or PDU session context update request message does not include the first indication information, which is used to indicate that the second access network device supports multicast / broadcast services, then the session management network element can determine that the second access network device does not support multicast / broadcast services.

[0249] The first indication information can also be called multicast / broadcast capability information. This multicast / broadcast capability information can be used to indicate whether the second access network device supports multicast / broadcast services. For example, this capability information can be an indication, a tag, or an information element (IE).

[0250] In this application, whether a second access network device supports multicast / broadcast can be characterized by whether at least one of the N2 path switch request message, the path switch request message, and the PDU session context update request message carries specific information, elements, or tags. For example, carrying multicast / broadcast capability information of the second access network device indicates that the second access network device supports multicast / broadcast services; not carrying multicast / broadcast capability information indicates that the second access network device does not support multicast / broadcast. As another example, carrying multicast / broadcast capability information of the second access network device and indicating whether the second access network device supports multicast / broadcast can be done, for example, in a Boolean manner (i.e., 1 represents support, 0 represents no support).

[0251] The session management network element can determine whether the second access network device supports multicast / broadcast services. If the second access network device does not support multicast / broadcast services, the session management network element can send the fifth information to the second access network device. This fifth information is used to activate the third QoS flow. If the second access network device supports multicast / broadcast services, the session management network element may not send the fifth information to the second access network device.

[0252] It should be noted that the above Figure 4 The various implementation scenarios shown in the embodiments can be combined with each other without limitation.

[0253] Figure 5 A schematic diagram of a data transmission method 300 provided in an embodiment of this application is shown. Method 300 may include the following steps.

[0254] S310, the terminal device obtains the status of the first PDU session and the status of the associated QoS flow of the first PDU session.

[0255] The state of the first PDU session can include an active state and a deactivated state.

[0256] Specifically, the terminal device can determine the state of the first PDU session based on the first PDU session context. The context of the first PDU session can be stored in the terminal device or obtained from other network elements, without restriction.

[0257] Specifically, the terminal device can determine the state of the first PDU session based on the context of the first PDU session in the following ways:

[0258] Method 1: The terminal device determines the state of the first PDU session based on the state information in the context of the first PDU session.

[0259] Specifically, the context of the first PDU session includes the state information of the first PDU session, which includes "activated" and "deactivated / inactive / deactive". If the state information is "activated", the terminal device determines that the state of the first PDU session is active; or, if the state information is "deactivated / inactive / deactive", the terminal device determines that the state of the first PDU session is deactivated.

[0260] It should be understood that in this case, the terminal device can receive a third trigger message sent by the first access network device. The third trigger message notification message is used to update the state of the first PDU session. If the terminal device receives the third trigger message, it can update the state information of the first PDU session according to the third trigger message.

[0261] It should be noted that the third trigger message sent by the first access network device can be a direct forwarding of a message from the core network, or it can be generated by the first access network device based on a message from the core network.

[0262] For example, if a terminal device receives a PDU session modification acceptance message, which includes the identification information of the first PDU session, the terminal device will set the status of the first PDU session to active.

[0263] Method 2: The terminal device determines the state of the first PDU session by judging whether the context of the first PDU session contains specific information related to the activation state.

[0264] Among them, the specific information related to the activation state can be called the second activation state information. This second activation state information may include the air interface resource information of the first PDU session, such as the configuration information of the packet data convergence protocol (PDCP).

[0265] The terminal device can determine the state of the first PDU session based on whether the context of the first PDU session contains the second activation state information. When the context includes the second activation state information, the terminal device determines that the state of the first PDU session is active. Alternatively, when the context does not contain the second activation state information, the terminal device determines that the state of the first PDU session is deactivated.

[0266] The status of the associated QoS flows of the first PDU session can include both all associated QoS flows of the first PDU session being active and not all associated QoS flows of the first PDU session being active. Alternatively, the status of the associated QoS flows of the first PDU session can include both active and deactivated states.

[0267] In one optional implementation, the state of the associated QoS flows of the first PDU session includes both a state where all associated QoS flows of the first PDU session are active and a state where not all associated QoS flows of the first PDU session are active.

[0268] Optionally, the method 300 further includes: the terminal device receiving the third information, wherein the third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session; or, the third information is used to indicate that not all associated QoS flows of the first PDU session are in an active state.

[0269] The third piece of information can be the PDU session reactivation result.

[0270] Specifically, the terminal device can use third information to determine whether all associated QoS flows of the first PDU session are active.

[0271] For example, if the third information is used to indicate that not all associated QoS flows of the first PDU session are active, the terminal device can determine that not all associated QoS flows of the first PDU session are active based on the indication of the third information.

[0272] For example, if the third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session, the terminal device can know which QoS flows in the associated QoS flows of the first PDU session are activated based on the QFI of the activated QoS flows in the third information, and thus determine that not all of the first PDU sessions are in an active state.

[0273] In another alternative implementation, the state of the associated QoS flow of the first PDU session includes an active state and a deactivated state.

[0274] Specifically, the terminal device can determine the status of the associated QoS flow of the first PDU session based on the context of the first PDU session. The context of the first PDU session includes the status information of the associated QoS flow, and there is a one-to-one correspondence between the associated QoS flow and its status information. The context of the first PDU session can be stored in the terminal device or obtained from other network elements, without restriction.

[0275] Specifically, the associated QoS flows of the first PDU session include one or more QoS flows, any one of which is denoted as QoS flow X. The context of the first PDU session includes the correspondence between QoS flow X and its status information, which includes "activated" and "deactivated / inactive / deactive". If the status information of QoS flow X is "activated", the terminal device determines that the status of QoS flow X is active; or, if the status information of QoS flow X is "deactivated / inactive / deactive", the terminal device determines that the status of QoS flow X is deactivated.

[0276] It should be understood that in this case, the terminal device can receive a notification message sent by the first access network device. This notification message is used to notify the status of the associated QoS flow of the first PDU session. The terminal device can update the status information of the associated QoS flow of the first PDU session according to the notification message.

[0277] For example, the notification message can be the aforementioned third information. Specifically, the third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session. The third information may include the QFI of the activated QoS flows, and the terminal device sets the status of these QoS flows to the active state according to the third information.

[0278] S320, if the first PDU session is active and not all associated QoS flows of the first PDU session are active, the terminal device sends a service request message to the session management network element. The service request message is used to request the transmission of unicast service data through the first PDU session; and / or, if the first PDU session is active and all associated QoS flows of the first PDU session are active, the terminal device does not send a service request message.

[0279] Specifically, assuming the terminal device needs to transmit unicast services through the first PDU session, if the first PDU session is active and not all associated QoS flows of the first PDU session are active, the terminal device can send a service request message. Furthermore, the session management network element can trigger the first access network device to activate a second QoS flow based on this service request message. The second QoS flow can be any QoS flow in the associated QoS flows of the first PDU session other than the aforementioned QoS flows, allowing the terminal device to transmit the unicast service data through the second QoS flow. Alternatively, if the first PDU session is active and all associated QoS flows of the first PDU session are active, the terminal device determines that the associated QoS flows of the first PDU session can be used to transmit the unicast service data. Therefore, the terminal device will transmit the unicast service data through the associated QoS flows of the first PDU session; that is, the terminal device does not send a service request message.

[0280] According to the method provided in the above embodiments, when a terminal device has a unicast service transmission requirement, the terminal device can determine whether to send a service request message based on the current PDU session status and the status of the associated QoS streams of the PDU session. If the first PDU session is active and not all associated QoS streams of the first PDU session are active, the terminal device sends a service request message; and / or, if the first PDU session is active and all associated QoS streams of the first PDU session are active, no service request message is sent. This approach helps reduce resource waste and allows for more rational use of air interface resources while ensuring normal data transmission for unicast services.

[0281] Optionally, in one implementation scenario of the above embodiments, the method 300 may further include: S330, the terminal device sends a join request message to the session management network element through the first PDU session.

[0282] Accordingly, the session management network element receives the join request message through the first PDU session.

[0283] The join request message is used to request to join a multicast service. In other words, it requests to join a multicast session associated with a multicast service, or a multicast group associated with a multicast service. Specifically, the join request message may include the identification information of the multicast service.

[0284] The service identification information for multicast services can be the identifier of the multicast service, such as one or more of the following: the identifier of the multicast / broadcast service, the name of the multicast / broadcast service, the multicast / broadcast address of the multicast / broadcast service, the multicast / broadcast IP address of the multicast / broadcast service, the temporary mobile group identity (TMGI) corresponding to the multicast / broadcast service, the session address of the multicast / broadcast service, the identifier of the multicast session, the identifier of the multicast group, etc.

[0285] Furthermore, the join request message may include identification information of the first PDU session. Specifically, the join request message may be a PDU session modification request message or a PDU session establishment request message, or other NAS messages. The identification information of the first PDU session can be used to identify the first PDU session, for example, a PDU session ID.

[0286] Sending or receiving join request messages through the first PDU session can be understood as sending or receiving join request messages through the control plane of the first PDU session.

[0287] It should be noted that sending or receiving a join request message through the first PDU session can be replaced with sending or receiving a join request message that includes the identifier of the first PDU session.

[0288] For ease of understanding, the following will be used as an example. Figure 2 Taking network elements as an example, combined with Figure 6 The embodiments of this application will be described in detail.

[0289] Figure 6 This illustration shows another schematic diagram of a data transmission method 400 provided in an embodiment of this application. Exemplarily, Figure 6 The method 400 shown can be considered as a specific implementation of methods 200 and 300. Method 400 may include the following steps.

[0290] S401, AF, MB-SMF, and MB-UPF are used to create multicast sessions and configure multicast service parameters.

[0291] When an AS has a multicast service transmission requirement, the AF can send a request message to the Network Exposure Function (NEF). This request message requests the establishment of a multicast session associated with the multicast service. Further, the NEF determines the MB-SMF (Multicast Management Function) for managing the multicast session based on the request message and sends a request message to the MB-SMF. Upon receiving the request message, the MB-SMF determines the multicast service policy information based on the pre-configured mapping relationship between service identifier information and policies, and establishes the multicast session associated with the multicast service based on the determined multicast service policy information.

[0292] After the multicast session is created, the AF provides the parameters of the multicast service to the MB-SMF. These parameters may include multicast service requirement information and the identifier of the multicast session.

[0293] The multicast service requirement information mentioned above may include: the bandwidth required for the multicast service, the data transmission priority of the multicast service, or the QoS information of the multicast service.

[0294] It should be understood that if the above multicast service requirement information does not include the QoS information of multicast services, then MB-SMF can generate the QoS information of multicast services based on the policy information of multicast services.

[0295] MB-SMF configures MB-UPF based on the parameters of multicast services. For example, it configures MB-UPF to identify multicast service data and configures the forwarding rules for multicast service data in MB-UPF.

[0296] It should be noted that the parameters for the aforementioned multicast service can be sent directly from the AF network element to the MB-SMF network element, or they can be sent to the MB-SMF network element via one or more of the following network elements: NEF network element ( Figure 6 (not shown in the image), PCF network element ( Figure 6 (not shown in the image), UDM network element ( Figure 6 (not shown in the image), etc.

[0297] S402, AF sends a service announcement to UE.

[0298] Specifically, the service announcement includes identification information for multicast sessions associated with the multicast service.

[0299] S403, the UE sends a join request message to the SMF.

[0300] The join request message is used to request to join the multicast service, and the join request message includes the identification information of the multicast session associated with the multicast service.

[0301] Correspondingly, the SMF receives the join request message.

[0302] In this embodiment, the example is taken where the UE sends a join request message to the SMF network element through PDU session #1.

[0303] The join request message can be a PDU session modification request message or a PDU session establishment request message, etc., and includes the PDU session ID of PDU session #1. The join request message also includes the identification information of the aforementioned multicast session.

[0304] S404, SMF obtains information about multicast services and determines a portion of the QoS flow based on this information.

[0305] Specifically, the SMF obtains multicast service information from the MB-SMF based on the identification information of the multicast session. This multicast service information includes the QoS information of the multicast service.

[0306] For example, based on the QoS information of the multicast service, the SMF maps the QoS flow of the multicast service to a portion of the QoS flow in the associated QoS flow of PDU session #1. This portion of the QoS flow is used to transmit the data of the multicast service, and the QoS parameters of this portion of the QoS flow are the same as the QoS parameters of the multicast QoS flow.

[0307] For example, assuming that the multicast QoS stream of the multicast service includes QoS stream 5 and QoS stream 6, the associated QoS stream of the first PDU session may include four: QoS stream 1, QoS stream 2, QoS stream 3, and QoS stream 4. Among these four QoS streams, QoS stream 3 and QoS stream 5 have the same QoS parameters, and QoS stream 4 and QoS stream 5 have the same QoS parameters. Therefore, the QoS streams used to transmit the data of the above multicast service in the associated QoS streams of the first PDU session refer to QoS stream 3 and QoS stream 4.

[0308] S405, SMF determines the status of PDU session #1.

[0309] Specifically, referring to method 200 above, the SMF can determine the state of PDU session #1 based on the context of PDU session #1.

[0310] The following descriptions are based on two scenarios: PDU session #1 is in an active state and PDU session #1 is in a deactivated state.

[0311] Scenario 1: PDU session #1 is active. It can be handled according to the current standard definition.

[0312] Case 2: PDU session #1 is in a deactivated state, execute S406-S424.

[0313] S406, SMF triggers the response process for the join request message.

[0314] For example, if the join request message is a PDU session modification request message, the SMF can send a PDU session modification acceptance message to the UE through the AMF.

[0315] Specifically, the SMF sends an N11 message to the AMF, which can be a PDU session context update response (Nsmf_PDUsession_updateSMcontext response) message. This N11 message includes an N1 SM container, which contains a PDU session modification accept message. The PDU session modification accept message is used to respond to the join request message.

[0316] The PDU session modification acceptance message includes the PDU session ID of PDU session #1 and the identification information of the multicast session.

[0317] AMF sends a NAS message to the UE, which includes a PDU session modification acceptance message.

[0318] S407, SMF determines the status of a multicast session.

[0319] Specifically, the SMF can obtain the status of the multicast session from the MB-SMF and determine whether the multicast session is active or inactive.

[0320] The specific method by which the SMF obtains the state of the multicast session from the MB-SMF can be found in the description of method 200 above.

[0321] The following descriptions are based on two scenarios: the multicast session is in an active state and the multicast session is in an inactive state.

[0322] Case 2-1: If the multicast session is active, execute S408 to S410, but not S411 to S416.

[0323] S408, SMF sends a request message to gNB1, which carries information #1.

[0324] Specifically, information #1 is used to activate this portion of the QoS flow. Information #1 can be the QoS information of the aforementioned portion of the QoS flow.

[0325] Specifically, QoS information may include the QFI of this portion of the QoS flow.

[0326] Optionally, the QoS information may also include the QoS parameters of that portion of the QoS flow.

[0327] Specifically, the SMF sends an N11 message to the AMF, which can be an N1N2 message transfer (Namf_communication_N1N2MessageTransfer). This N11 message includes an N2 SM container, and the N2 SM container includes information #1. The AMF sends an N2 message to gNB1. This N2 message can be an NGAP PDU session resource setup request message or an NGAP PDU session resource modification request message, and the N2 message includes information #1.

[0328] S409, gNB1 sends an RRC reconfiguration message to the UE, and the UE sends an RRC reconfiguration response message to gNB1.

[0329] Specifically, gNB1 can generate DRB reconfiguration information based on the QoS parameters in information #1, and then gNB1 sends an RRC reconfiguration message to the UE, which includes the DRB reconfiguration information.

[0330] Furthermore, the UE receives the RRC reconfiguration message, configures resources according to the DRB reconfiguration information, and then sends an RRC reconfiguration response message to gNB1.

[0331] S410, gNB1 sends a response message to SMF.

[0332] This response message is used to respond to the request message of S408.

[0333] After receiving the RRC reconfiguration response message, gNB1 sends a response message to SMF through AMF. This response message is either a PDU session resource setup response message or a PDU session resource modify response message.

[0334] Case 2-2: When the multicast session is in an inactive state, execute S411 to S416, but do not execute S408 to S410.

[0335] S411, MB-SMF receives the second trigger message.

[0336] The second trigger message is either an MBS session update request message or an N4 notification message.

[0337] For example, the MB-SMF receives an MBS session update request (Nmbsmf_MBSSession Update_Request) message from the AF, which is used to request the activation of the multicast session associated with the multicast service. Or the MB-SMF receives an N4 notification (N4mb notification) message from the MB-UPF, which is used to notify that the multicast session associated with the multicast service has been activated.

[0338] S412, MB-SMF sends message #2 to SMF.

[0339] Message #2 is used to notify that a multicast session has been activated.

[0340] Specifically, information #2 can be a session status indication, which indicates the status of the multicast session. The MB-SMF sends an MBS session context status notification (Nmbsmf_MBSsession_contextstatusnotify) message to the SMF, which includes information #2.

[0341] S413, SMF triggers AMF to paging UE.

[0342] It should be understood that S413 is an optional step. When a multicast session is activated, if the UE is in a disconnected state, the SMF can trigger the AMF to paging the UE.

[0343] Specifically, the SMF sends a group reachability (Namf_MT_groupreachability) message to the AMF, which includes a list of UEs that have previously requested to join the multicast service. The AMF then pages the idle UEs in the UE list based on the group reachability message.

[0344] Paging can be a single paging for a specific UE, or a group paging for UEs in a UE list.

[0345] S414, when the UE is in connected state, the SMF sends a request message to gNB1, which carries information #1.

[0346] Specifically, the specific processes of S414 to S416 can be referred to S408 to S410, and will not be repeated here.

[0347] In other words, if the multicast session is in a deactivated state, the SMF waits for the multicast session to be activated before activating a portion of the QoS stream in the associated QoS stream of PDU session #1. This portion of the QoS stream is used to transmit data for multicast services.

[0348] S412 can be viewed as a notification message indicating that a multicast session has been activated, or as a triggering condition for S413.

[0349] After passing through S408-S410 or S411-S416, the portion of the QoS stream used for transmitting multicast service data in the associated QoS stream of PDU session #1 is activated.

[0350] S417, SMF sends message #3 to UE.

[0351] Specifically, information #3 is used to notify the activated QoS flows in the associated QoS flows of the first PDU session. For example, information #3 includes the QFI of the aforementioned partial QoS flows; or, information #3 is used to indicate that not all associated QoS flows of the first PDU session are active.

[0352] Specifically, the SMF sends an N11 message to the AMF, which can be an N1N2 message transfer (Namf_communication_N1N2MessageTransfer) message. The N11 message includes an N1 SM container, and the N1 SM container includes information #3. The AMF sends an N1 message to gNB1, which can be a NAS message. gNB1 then sends the N1 message to the UE, and this N1 message includes information #3.

[0353] It should be understood that S417 can be executed after S410 or after S416.

[0354] Optionally, in certain circumstances, S418 to S421, and / or S422 to S424 may also be performed.

[0355] The following descriptions are divided into scenario A and scenario B.

[0356] It should be noted that the solutions for scenario A and scenario B can be implemented independently or in combination, without restriction.

[0357] Scenario A: The UE has a unicast service transmission requirement, so execute steps 418 to S421.

[0358] S418, the UE obtains the status of PDU session #1 and the status of the associated QoS flow of PDU session #1.

[0359] Specifically, referring to methods 200 and 300 above, the UE can determine the state of PDU session #1 and the state of the associated QoS flow of PDU session #1 based on the context of PDU session #1.

[0360] One way to obtain the status of the associated QoS flow of PDU session #1 is based on information #3 in S417.

[0361] S419, if PDU session #1 is in an active state and not all associated QoS flows of PDU session #1 are in an active state, then the UE sends a service request message to the SMF, which is used to request the transmission of unicast services.

[0362] If PDU session # is active and all associated QoS flows of PDU session #1 are active, then S419 will not be executed.

[0363] S420, SMF sends message #4 to gNB1.

[0364] Specifically, information #4 is used to activate the second QoS flow in the associated QoS flow of PDU session #1.

[0365] The second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit the data of the unicast service. For example, suppose the associated QoS streams of the first PDU session may include four: QoS stream 1, QoS stream 2, QoS stream 3, and QoS stream 4; among these four QoS streams, the QoS stream used to transmit the data of the aforementioned unicast service is QoS stream 1, and the second QoS stream here refers to QoS stream 1. Alternatively, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state. For example, suppose the associated QoS streams of the first PDU session may include four: QoS stream 1, QoS stream 2, QoS stream 3, and QoS stream 4; among these four QoS streams, the QoS streams in an active state are QoS stream 3 and QoS stream 4, and the QoS streams in a deactivated state are QoS stream 1 and QoS stream 2, and the second QoS stream here refers to QoS stream 1 and QoS stream 2.

[0366] Among them, information #4 can be the QoS information of the second QoS stream.

[0367] Specifically, the QoS information includes the QFI of the second QoS flow.

[0368] Optionally, the QoS information may also include the QoS parameters of the second QoS flow.

[0369] Specifically, the SMF sends an N11 message to the AMF. The N11 message can be an N1N2 message transfer (Namf_Communication_N1N2MessageTransfer) message, which includes the N2 SM container. The N2 SM container includes information #4. After receiving the N11 message from the SMF, the AMF sends an N2 message to gNB1. This N2 message can be an NGAP PDU session resource modify message, which also includes information #4.

[0370] S421, gNB1 sends an RRC reconfiguration message to the UE, and the UE sends an RRC reconfiguration response message to gNB1.

[0371] Specifically, gNB1 can generate DRB reconfiguration information based on the QoS parameters in information #4, and then gNB1 sends an RRC reconfiguration message to the UE, which includes the DRB reconfiguration information.

[0372] Furthermore, the UE receives the RRC reconfiguration message, configures resources according to the DRB reconfiguration information, and then sends an RRC reconfiguration response message to gNB1.

[0373] After S418-S421, the second QoS stream in the associated QoS stream of PDU session #1 is activated, and the second QoS stream can be used by the UE to transmit unicast service data.

[0374] In scenario B, the UE switches from gNB1 to gNB2, which does not support MBS, and executes steps 422 to S424.

[0375] S422, gNB2 sends an N2 message to SMF, which includes the identification information of PDU session #1.

[0376] Optionally, the N2 message does not include indication information #1, which is used to indicate that gNB2 supports MBS, so that the SMF knows that gNB2 does not support MBS.

[0377] The N2 message can be an N2 path switch request or a pathswitch request message. The AMF can send the N2 message to the SMF via the N11 message, which can be a PDU session context update request (Nsmf_PDUsession_updateSMcontext request).

[0378] If the N2 path switching request, path switching message, or PDU session context update request message does not include indication information #1, which indicates that gNB2 supports MBS, then the SMF can determine that gNB2 does not support MBS.

[0379] S423, SMF sends message #5 to gNB2.

[0380] Specifically, information #5 is used to activate the third QoS flow in the associated QoS flow of PDU session #1.

[0381] The third QoS flow is an associated QoS flow of the first PDU session and is in a deactivated state. For example, suppose the associated QoS flows of the first PDU session may include four: QoS flow 1, QoS flow 2, QoS flow 3, and QoS flow 4; among these four QoS flows, the active QoS flows are QoS flow 3 and QoS flow 4, and the deactivated QoS flows are QoS flow 1 and QoS flow 2. The third QoS flow here refers to QoS flow 1 and QoS flow 2.

[0382] Among them, information #5 can be the QoS information of the third QoS stream.

[0383] Specifically, the QoS information includes the QFI of the third QoS flow.

[0384] Optionally, the QoS information may also include the QoS parameters of the third QoS flow.

[0385] Specifically, the SMF sends an N11 message to the AMF. The N11 message can be an N1N2 message transfer (Namf_communication_N1N2MessageTransfer) message, which includes an N2 SM container. The N2 SM container contains information #5. After receiving the N11 message from the SMF, the AMF sends an N2 message to gNB2. This N2 message can be an NGAP PDU session resource modify message, which also includes information #5.

[0386] S424, gNB2 sends an RRC reconfiguration message to the UE, and the UE sends an RRC reconfiguration response message to gNB2.

[0387] Specifically, gNB2 can generate DRB reconfiguration information based on the QoS parameters in information #5, and then gNB2 sends an RRC reconfiguration message to the UE, which includes the DRB reconfiguration information.

[0388] Furthermore, the UE receives the RRC reconfiguration message, configures resources according to the DRB reconfiguration information, and then sends an RRC reconfiguration response message to gNB2.

[0389] After S422-S424, the third QoS stream in the associated QoS stream of PDU session #1 is activated. The third QoS stream can be used by the UE to transmit data in unicast mode after handover.

[0390] It should be understood that S418 to S421 described above can be one of the cases in method 400, or they can be independent solutions, and this application does not limit them. If S418 to S421 are independent solutions, they can be regarded as a specific implementation of method 500 described above.

[0391] Figure 7 A schematic diagram of a data transmission apparatus 700 provided in an embodiment of this application is shown.

[0392] The device 700 includes a transceiver unit 710 and a processing unit 720. The transceiver unit 710 can be used to implement corresponding communication functions. The transceiver unit 710 can also be called a communication interface or a communication unit. The processing unit 720 can be used to perform data processing.

[0393] Optionally, the device 700 further includes a storage unit, which can be used to store instructions and / or data. The processing unit 720 can read the instructions and / or data in the storage unit so that the device can perform the actions of different devices in the foregoing method embodiments, such as the actions of a terminal device, a session management network element, a first access network device, or a second access network device.

[0394] As a design feature, the device 700 is used to perform the actions performed by the session management network element in the various method embodiments described above.

[0395] At this time, the device 700 can be a session management network element or a component of a session management network element. The transceiver unit 710 is used to perform transceiver-related operations on the session management network element side in the above method embodiment, and the processing unit 720 is used to perform processing-related operations on the session management network element side in the above method embodiment.

[0396] In one possible implementation, the transceiver unit 710 is configured to receive a join request message from a terminal device through a first protocol data unit (PDU) session, the join request message being used to request to join a multicast service; and the processing unit 720 is configured to send first information to a first access network device if the first PDU session is in a deactivated state, the first information being used to activate a portion of the QoS stream in the associated QoS stream of the first PDU session, the portion of the QoS stream being used to transmit data for the multicast service.

[0397] Optionally, the first information includes identification information for a portion of the QoS flow.

[0398] Optionally, the processing unit 720 is specifically configured to: send first information to the first access network device if the multicast session associated with the multicast service is in an active state; and / or send first information to the first access network device if the multicast session associated with the multicast service changes from a deactivated state to an active state.

[0399] Optionally, the transceiver unit 710 is further configured to: receive second information, the second information being used to notify that the multicast session is activated; the processing unit 720 is further configured to: if the multicast session is in a deactivated state, determine, based on the second information, that the multicast session changes from a deactivated state to an activated state.

[0400] Optionally, the transceiver unit 710 is further configured to: send third information to the terminal device; wherein the third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session; or, the third information is used to indicate that not all associated QoS flows of the first PDU session are in an active state.

[0401] Optionally, the processing unit 720 is further configured to: if a service request message is received from a terminal device, and the service request message is used to request the transmission of unicast service data through the first PDU session, then send fourth information to the first access network device, the fourth information being used to activate the second QoS stream; wherein the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit unicast service data; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

[0402] Optionally, if the terminal device moves from the first access network device to the second access network device, the processing unit 720 is further configured to: if the path switching request message or the PDU session context update request message does not include the first indication information, the first indication information being used to indicate that the second access network device supports multicast / broadcast services, then send fifth information to the second access network device, the fifth information being used to activate the third QoS flow, the third QoS flow being an associated QoS flow of the first PDU session and being in a deactivated state; or, if the second access network device does not support multicast / broadcast services, then send fifth information to the second access network device.

[0403] The device 700 can implement steps or processes corresponding to those executed by the session management network element in the method embodiment according to the present application. The device 700 may include tools for performing... Figure 4 or Figure 5 The method executed by the session management network element in the illustrated embodiment may include units or components. Figures 4 to 6 A unit of the method executed by SMF in any of the illustrated embodiments.

[0404] It should be understood that the specific process of each unit performing the above-mentioned corresponding steps has been described in detail in the above-mentioned method embodiments, and will not be repeated here for the sake of brevity.

[0405] As an alternative design, the device 700 can be used to perform the actions performed by the terminal device in the various method embodiments described above. In this case, the device 700 can be a terminal device or a component of a terminal device. The transceiver unit 710 is used to perform transceiver-related operations on the terminal device side in the method embodiments described above, and the processing unit 720 is used to perform processing-related operations on the terminal device side in the method embodiments described above.

[0406] One possible implementation is that the processing unit 720 is used to obtain the status of the first Protocol Data Unit (PDU) session and the status of the associated QoS streams of the first PDU session; the processing unit 720 is further used to: if the first PDU session is in an active state and not all associated QoS streams of the first PDU session are in an active state, then send a service request message to the core network device, the service request message being used to request the transmission of unicast service data through the first PDU session; and / or, if the first PDU session is in an active state and all QoS streams in the associated QoS streams of the first PDU session are in an active state, then do not send a service request message.

[0407] Optionally, the processing unit 720 is specifically configured to: receive third information; wherein the third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session; or, the third information is used to indicate that not all associated QoS flows of the first PDU session are in an active state.

[0408] Optionally, the device 700 further includes a transceiver unit 710, configured to send a join request message through a first PDU session, the join request message being used to request to join a multicast service.

[0409] The device 700 can implement steps or processes corresponding to those executed by a terminal device in a method embodiment according to the present application. The device 700 may include methods for performing... Figure 4 or Figure 5 The terminal device in the illustrated embodiment executes a method unit, or includes... Figures 4 to 6 A unit of the method executed by the UE in any of the illustrated embodiments.

[0410] It should be understood that the specific process of each unit performing the above-mentioned corresponding steps has been described in detail in the above-mentioned method embodiments, and will not be repeated here for the sake of brevity.

[0411] As an alternative design, the device 700 can be used to perform the actions performed by the first access network device in the various method embodiments described above. In this case, the device 700 can be the first access network device or a component of the first access network device. The transceiver unit 710 is used to perform transceiver-related operations on the first access network device side in the method embodiments described above, and the processing unit 720 is used to perform processing-related operations on the first access network device side in the method embodiments described above.

[0412] In one possible implementation, the transceiver unit 710 is configured to receive first information, which is used to activate a portion of the QoS stream in the associated QoS stream of the first PDU session, the portion of the QoS stream being used to transmit multicast service data. The processing unit 720 is configured to activate the portion of the QoS stream based on the first information.

[0413] Optionally, the transceiver unit 710 is further configured to: receive fourth information, the fourth information being used to activate a second QoS stream; wherein the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit data for unicast services; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state; the processing unit 720 is further configured to: activate the second QoS stream according to the fourth information.

[0414] The device 700 can implement steps or processes corresponding to those executed by the first access network device in the method embodiment according to the present application. The device 700 may include tools for performing... Figure 4 The method executed by the first access network device in the illustrated embodiment may include units or components. Figure 6 The unit of the method executed by gNB1 in the illustrated embodiment.

[0415] It should be understood that the specific process of each unit performing the above-mentioned corresponding steps has been described in detail in the above-mentioned method embodiments, and will not be repeated here for the sake of brevity.

[0416] It should also be understood that the device 700 here is embodied in the form of a functional unit. The term "unit" here can refer to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (e.g., a shared processor, a proprietary processor, or a group processor, etc.) and memory for executing one or more software or firmware programs, integrated logic circuitry, and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art will understand that the device 700 may specifically be a session management network element in the above embodiments, used to execute the various processes and / or steps corresponding to the session management network element in the above method embodiments; or, the device 700 may specifically be a terminal device in the above embodiments, used to execute the various processes and / or steps corresponding to the terminal device in the above method embodiments. To avoid repetition, further details are omitted here.

[0417] The apparatus 700 of each of the above-described schemes has the function of implementing the corresponding steps performed by the session management network element in the above-described method, or the apparatus 700 of each of the above-described schemes has the function of implementing the corresponding steps performed by the terminal device in the above-described method. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit can be replaced by a transceiver (e.g., the sending unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as processing units, can be replaced by processors, respectively executing the transceiver operations and related processing operations in each method embodiment.

[0418] In addition, the transceiver unit 710 described above can also be a transceiver circuit (for example, it may include a receiving circuit and a transmitting circuit), and the processing unit can be a processing circuit.

[0419] It should be pointed out that, Figure 7 The device mentioned can be the network element or equipment in the foregoing embodiments, or it can be a chip or chip system, such as a system on chip (SoC). The transceiver unit can be an input / output circuit or a communication interface; the processing unit is a processor, microprocessor, or integrated circuit integrated on the chip. No limitations are imposed here.

[0420] Figure 8A schematic diagram of a data transmission apparatus 800 provided in an embodiment of this application is shown. The apparatus 800 includes a processor 810 coupled to a memory 820 for storing computer programs or instructions and / or data. The processor 810 is used to execute the computer programs or instructions stored in the memory 820, or to read the data stored in the memory 820, to perform the methods in the above-described method embodiments. Figure 8 As shown, the device 800 also includes a transceiver 830 for receiving and / or transmitting signals. For example, a processor 810 is used to control the transceiver 830 to receive and / or transmit signals.

[0421] Optionally, there may be one or more processors 810.

[0422] Optionally, the memory 820 may be one or more.

[0423] Alternatively, the memory 820 can be integrated with the processor 810, or it can be set separately.

[0424] As one approach, the device 800 is used to implement the operations performed by the session management network element, the first access network device, or the terminal device in the various method embodiments described above.

[0425] For example, processor 810 is used to execute computer programs or instructions stored in memory 820 to implement the relevant operations of the session management network element in the various method embodiments described above. For example, Figure 4 or Figure 5 The method executed by the session management network element in the illustrated embodiment, or Figures 4 to 6 The method executed by the session management network element or SMF in any of the illustrated embodiments.

[0426] For example, processor 810 is used to execute computer programs or instructions stored in memory 820 to implement the relevant operations of the terminal device in the various method embodiments described above. For example, Figure 4 or Figure 5 The method executed by the terminal device in the illustrated embodiment, or Figures 4 to 6 The method executed by the terminal device or UE in any of the illustrated embodiments.

[0427] It should be understood that the processor mentioned in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0428] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory and / or non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0429] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) can be integrated into the processor.

[0430] It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0431] This application also provides a computer-readable medium having a computer program stored thereon, which, when executed by a computer, implements the functions of any of the above method embodiments.

[0432] This application also provides a computer program product that, when executed by a computer, implements the functions of any of the above method embodiments.

[0433] This application also provides a system that includes the session management network element and the first access network device in the foregoing embodiments.

[0434] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0435] In the embodiments of this application, the words "exemplary," "for example," etc., are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design that is described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0436] It should be understood that the term "embodiment" used throughout this specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, various embodiments throughout this specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0437] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. All node and message names in this application are merely names set for the convenience of description, and the names in the actual network may be different. It should not be understood that this application limits the names of various nodes and messages. On the contrary, any name with the same or similar function as the node or message used in this application is regarded as the method or equivalent substitution of this application and is within the protection scope of this application.

[0438] It should also be understood that in this application, “when…”, “if” and “if” all refer to the UE or base station taking corresponding actions under certain objective circumstances, and are not time-limited, nor do they require the UE or base station to perform a judgment action, nor do they imply any other limitations.

[0439] It should be noted that in the embodiments of this application, "pre-setting" and "pre-configuration" can be implemented by pre-saving the corresponding code, table or other means that can be used to indicate relevant information in the device (e.g., terminal device). This application does not limit the specific implementation method, such as the preset rules and preset constants in the embodiments of this application.

[0440] In addition, the terms “system” and “network” are often used interchangeably in this article.

[0441] In this document, the terms "at least one of..." or "at least one of..." refer to all or any combination of the listed items. For example, "at least one of A, B, and C" can represent six possibilities: A exists alone, B exists alone, C exists alone, A and B exist simultaneously, B and C exist simultaneously, and A, B, and C exist simultaneously. "At least one" in this document means one or more. "More than one" means two or more.

[0442] It should be understood that in the embodiments of this application, "B corresponding to A" means that B is associated with A and B can be determined based on A. However, it should also be understood that determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0443] It should be understood that in the various embodiments of this application, the terms "first," "second," and various numerical designations are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. For example, they can be used to distinguish different information.

[0444] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0445] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0446] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0447] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0448] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0449] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0450] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for data transmission, characterized in that, include: The session management network element receives a join request message from the terminal device through the first protocol data unit (PDU) session. The join request message is used to request to join the multicast service. If the first PDU session is in a deactivated state, the session management network element sends first information to the first access network device. The first information is used to activate a portion of the QoS flow in the associated QoS flow of the first PDU session. The portion of the QoS flow is used to transmit the data of the multicast service.

2. The method according to claim 1, characterized in that, The first information includes the identification information of the portion of the QoS flow.

3. The method according to claim 1 or 2, characterized in that, The session management network element sends first information to the first access network device, including: If the multicast session associated with the multicast service is active, the session management network element sends the first information to the first access network device; and / or, If the multicast session associated with the multicast service changes from a deactivated state to an active state, the session management network element sends the first information to the first access network device.

4. The method according to claim 3, characterized in that, The method further includes: The session management network element receives second information, which is used to notify that the multicast session has been activated. If the multicast session is in a deactivated state, the session management network element determines, based on the second information, that the multicast session changes from a deactivated state to an activated state.

5. The method according to claim 1 or 2, characterized in that, The method further includes: The session management network element sends third information to the terminal device; The third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session; or, the third information is used to indicate that not all associated QoS flows of the first PDU session are in an active state.

6. The method according to claim 1 or 2, characterized in that, The method further includes: If a service request message is received from the terminal device, and the service request message is used to request the transmission of unicast service data through the first PDU session, then the session management network element sends fourth information to the first access network device, and the fourth information is used to activate the second QoS flow. Wherein, the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit the data of the unicast service; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

7. The method according to claim 1 or 2, characterized in that, The method is applied to a scenario where the terminal device moves from the first access network device to the second access network device, and the method further includes: If the path switching request message or the PDU session context update request message does not include the first indication information, where the first indication information is used to indicate that the second access network device supports multicast / broadcast services, then the session management network element sends fifth information to the second access network device. This fifth information is used to activate a third QoS flow, which belongs to the associated QoS flow of the first PDU session and is in a deactivated state; or... If the second access network device does not support multicast / broadcast services, the session management network element sends the fifth information to the second access network device.

8. A method for data transmission, characterized in that, include: The first access network device receives first information from the session management network element. The first information is used to activate a portion of the QoS flow in the associated QoS flow of the first PDU session. The portion of the QoS flow is used to transmit data for multicast services. The first access network device activates the portion of the QoS flow based on the first information.

9. The method according to claim 8, characterized in that, The first information includes the identification information of the portion of the QoS flow.

10. The method according to claim 8 or 9, characterized in that, The method further includes: The first access network device receives fourth information from the session management network element, the fourth information being used to activate the second QoS flow; The first access network device activates the second QoS flow based on the fourth information; Wherein, the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit unicast service data; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

11. A method for data transmission, characterized in that, include: The session management network element receives a join request message from the terminal device through the first protocol data unit (PDU) session. The join request message is used to request to join the multicast service. If the first PDU session is in a deactivated state, the session management network element sends first information to the first access network device. The first information is used to activate a portion of the QoS flow in the associated QoS flow of the first PDU session. The portion of the QoS flow is used to transmit the data of the multicast service. The first access network device activates the portion of the QoS flow based on the first information.

12. The method according to claim 11, characterized in that, The method further includes: If a service request message is received from the terminal device, and the service request message is used to request the transmission of unicast service data through the first PDU session, then the session management network element sends fourth information to the first access network device, and the fourth information is used to activate the second QoS flow. The first access network device activates the second QoS flow based on the fourth information; Wherein, the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit the unicast service; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

13. The method according to claim 11, characterized in that, The method further includes: If the path switching request message or the PDU session context update request message does not include the first indication information, whereby the first indication information is used to indicate that the second access network device supports multicast / broadcast services, then the session management network element sends fifth information to the second access network device. This fifth information is used to activate a third QoS flow, which belongs to the associated QoS flow of the first PDU session and is in a deactivated state; or... If the second access network device does not support multicast / broadcast services, the session management network element sends the fifth information to the second access network device; The second access network device activates the third QoS flow based on the fifth information.

14. A data transmission apparatus, characterized in that, include: The transceiver unit is used to receive a join request message from a terminal device through a first protocol data unit (PDU) session, wherein the join request message is used to request to join the multicast service; The processing unit is configured to send first information to the first access network device if the first PDU session is in a deactivated state. The first information is used to activate a portion of the QoS stream in the associated QoS stream of the first PDU session, and the portion of the QoS stream is used to transmit the data of the multicast service.

15. The apparatus according to claim 14, characterized in that, The first information includes the identification information of the portion of the QoS flow.

16. The apparatus according to claim 14 or 15, characterized in that, The processing unit is specifically used for: If the multicast session associated with the multicast service is active, then the first information is sent to the first access network device; and / or, If the multicast session associated with the multicast service changes from a deactivated state to an active state, the first information is sent to the first access network device.

17. The apparatus according to claim 16, characterized in that, The transceiver unit is further configured to: receive second information, the second information being used to notify that the multicast session has been activated; The processing unit is further configured to: if the multicast session is in a deactivated state, determine, based on the second information, that the multicast session changes from a deactivated state to an activated state.

18. The apparatus according to claim 14 or 15, characterized in that, The transceiver unit is also used for: Send third information to the terminal device; The third information is used to notify the activated QoS flows in the associated QoS flows of the first PDU session; or, the third information is used to indicate that not all associated QoS flows of the first PDU session are in an active state.

19. The apparatus according to claim 14 or 15, characterized in that, The processing unit is also used for: If a service request message is received from the terminal device, and the service request message is used to request the transmission of unicast service data through the first PDU session, then a fourth message is sent to the first access network device, and the fourth message is used to activate the second QoS flow. Wherein, the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit the data of the unicast service; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

20. The apparatus according to claim 14 or 15, characterized in that, The apparatus is applied to a scenario where the terminal device moves from the first access network device to the second access network device, and the processing unit is further configured to: If the path switching request message or the PDU session context update request message does not include the first indication information, which is used to indicate that the second access network device supports multicast / broadcast services, then the fifth information is sent to the second access network device. The fifth information is used to activate the third QoS flow, which belongs to the associated QoS flow of the first PDU session and is in a deactivated state. or, If the second access network device does not support multicast / broadcast services, then the fifth information is sent to the second access network device.

21. A data transmission apparatus, characterized in that, include: The transceiver unit is used to receive first information from the session management network element, the first information being used to activate a portion of the QoS stream in the associated QoS stream of the first PDU session, the portion of the QoS stream being used to transmit data for multicast services; A processing unit is configured to activate the portion of the QoS flow based on the first information.

22. The apparatus according to claim 21, characterized in that, The first information includes the identification information of the portion of the QoS flow.

23. The apparatus according to claim 21 or 22, characterized in that, The transceiver unit is further configured to: receive fourth information from the session management network element, the fourth information being used to activate the second QoS flow; The processing unit is further configured to: activate the second QoS flow according to the fourth information; Wherein, the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit unicast service data; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

24. A data transmission apparatus, characterized in that, include: A processor for executing a computer program stored in memory to cause the apparatus to perform the method as described in any one of claims 1 to 10.

25. The apparatus according to claim 24, characterized in that, The device also includes the memory.

26. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when run on a computer, causes the computer to perform the method as described in any one of claims 1 to 10.

27. A computer program product, characterized in that, The computer program product includes instructions for performing the method as described in any one of claims 1 to 10.

28. A communication system, characterized in that, include: Session management network elements and first access network devices, The session management network element is used for: The first protocol data unit (PDU) session receives a join request message from the terminal device, the join request message being used to request to join the multicast service; If the first PDU session is in a deactivated state, first information is sent to the first access network device. The first information is used to activate a portion of the QoS stream in the associated QoS stream of the first PDU session. The portion of the QoS stream is used to transmit the data of the multicast service. The first access network device is used for: Activate the portion of the QoS flow based on the first information.

29. The system according to claim 28, characterized in that, The session management network element is also used for: If a service request message is received from the terminal device, and the service request message is used to request the transmission of unicast service data through the first PDU session, then a fourth message is sent to the first access network device, and the fourth message is used to activate the second QoS flow. The first access network device is also used for: Activate the second QoS flow based on the fourth information; Wherein, the second QoS stream belongs to the associated QoS stream of the first PDU session and is used to transmit the unicast service; or, the second QoS stream belongs to the associated QoS stream of the first PDU session and is in a deactivated state.

30. The system according to claim 28, characterized in that, The system also includes a second access network device, wherein the terminal device moves from the first access network device to the second access network device. The session management network element is also used for: If the path switching request message or the PDU session context update request message does not include the first indication information, which is used to indicate that the second access network device supports multicast / broadcast services, then the fifth information is sent to the second access network device. The fifth information is used to activate the third QoS flow, which belongs to the associated QoS flow of the first PDU session and is in a deactivated state. or, If the second access network device does not support multicast / broadcast services, then the fifth information is sent to the second access network device; The second access network device is used for: The third QoS flow is activated based on the fifth information.

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