Communication method and communication device

Abstract

The present application provides a communication method and apparatus, in which a second access network device receives a first message from a first access network device, wherein the first message indicates whether the first state of an MBS session is activated or deactivated; and the second access network device sends a first confirmation message corresponding to the first message to the first access network device. In this solution, the first message indicates the first state of the MBS session, and the second access network device can determine whether to request the core network to establish a UP tunnel based on the first state. If the first state of the MBS session is activated, the second access network device can trigger a new UP tunnel to ensure normal MBS transmission during handover. If the first state of the MBS session is deactivated, the second access network device may not trigger a new UP tunnel or request a new pending UP tunnel, thereby avoiding resource waste.

Description

Technical Field

[0001] The present application relates to the field of communications, and in particular to a communication method and a communication device. Background Art

[0002] Multicast and broadcast service (MBS) is a service transmitted from access network equipment to multiple terminal devices. Common MBS services include live broadcast services, public safety services, and batch software updates. MBS data originates from a data server, is sent via core network equipment to access network equipment, and then from the access network equipment to at least one terminal device.

[0003] As a terminal device moves, its signal strength varies from cell to cell. To prevent a drop in communication quality due to deteriorating cell signal quality, it needs to switch from a first cell to a second cell. The first cell is served by a source access network device, while the second cell is served by a target access network device. The source access network device supports multicast broadcast transmission and provides MBS to the terminal device. However, if the target access network device does not have the MBS required by the terminal device, or if the target access network device does not support multicast broadcast transmission, ensuring the transmission of MBS data during the handover process is a pressing issue. Summary of the Invention

[0004] The communication method and apparatus provided in the embodiments of the present application can ensure normal transmission of the MBS during the handover process and avoid unnecessary waste of resources.

[0005] In a first aspect, a communication method is provided, which can be executed by a second access network device or a chip in the second access network device. The method includes: receiving a first message from the first access network device, wherein the first message indicates whether the first state of the MBS session is activated or deactivated; and sending a first confirmation message corresponding to the first message to the first access network device. In this solution, the first message is used to indicate the first state of the MBS session, and the second access network device can determine whether to request the core network to establish a UP tunnel based on the first state. If the first state of the MBS session is activated, the second access network device can trigger a new UP tunnel to ensure normal transmission of the MBS during the handover process; if the first state of the MBS session is deactivated, the second access network device may not trigger a new UP tunnel or request a new suspended UP tunnel to avoid resource waste.

[0006] In combination with the first aspect, the first message indicates that the first state of the multicast broadcast service MBS session is activated, and the method also includes: sending a first request message to the core network device, and the first request message is used to request the establishment of a user plane tunnel corresponding to the MBS session; or, the first message indicates that the first state of the multicast broadcast service MBS session is deactivated, and the method also includes: determining that there is no need to establish a user plane tunnel corresponding to the MBS session at present; or, the first message indicates that the first state of the multicast broadcast service MBS session is deactivated, and the method also includes: sending a first request message to the core network device, and the first request message is used to request the establishment of a user plane tunnel corresponding to the MBS session, and the user plane tunnel is suspended.

[0007] Optionally, the first message is a handover request message, and the first confirmation message is a handover request confirmation message.

[0008] Optionally, the first message includes first state information, and the first state information indicates whether the first state is activated or deactivated; or, the first message indicates whether the first state is activated or deactivated by whether it includes the first state information.

[0009] In a second aspect, a communication method is provided. The method can be executed by a first access network device or a chip in the first access network device. The method includes: sending a first message to a second access network device, wherein the first message indicates whether a first state of an MBS session is activated or deactivated; and receiving a first confirmation message corresponding to the first message from the second access network device. This solution ensures normal MBS transmission during handover and avoids resource waste.

[0010] Optionally, the first message is a handover request message, and the first confirmation message is a handover request confirmation message.

[0011] In combination with the second aspect, before sending the first message to the second access network device, the method further includes: receiving third information sent by a core network device, where the third information indicates the first state of the MBS session.

[0012] Optionally, the third information is information contained in the MBS session change message; or, the third information is information contained in a PDU session change message, wherein the PDU session is associated with the MBS session; or, the third information is information in an information field in the packet header of the data packet of the MBS service.

[0013] According to a third aspect, a communication method is provided, which can be executed by a second access network device or a chip in the second access network device. The method includes: sending a second message to a core network device; and receiving a second confirmation message corresponding to the second message from the core network device. The second message indicates whether the first status of the MBS session is active or deactivated; and / or the second confirmation message indicates whether the second status of the MBS session is active or deactivated. The MBS session status can be a first state or a second state, wherein the first state is the state of the MBS session before the terminal device is switched, and the second state is the state of the MBS session after the terminal device is switched. The MBS is an MBS that the terminal device is interested in or currently receiving. The second message and / or the second confirmation message allow the second access network device to obtain the MBS session status. If the MBS session status is active, the second access network device can trigger a new UP tunnel to ensure normal MBS transmission during the handover process. If the MBS session status is deactivated, the second access network device can not trigger a new UP tunnel or request the creation of a pending UP tunnel to avoid resource waste. On the other hand, during the handover process, the state of the MBS session may change. This solution can avoid the behavior mismatch problem caused by the change of the MBS session state.

[0014] In combination with the third aspect, the status of the MBS session is activated, and the method also includes: sending a first request message to the core network device, where the first request message is used to request the establishment of a user plane tunnel corresponding to the MBS session; or, the status of the MBS session is deactivated, and the method also includes: determining that there is currently no need to establish a user plane tunnel corresponding to the MBS session; or, the status of the MBS session is deactivated, and the method also includes: sending a first request message to the core network device, where the first request message is used to request the establishment of a user plane tunnel corresponding to the MBS session, and the user plane tunnel is suspended.

[0015] In combination with the third aspect, after receiving the second confirmation message from the core network device, the method further includes: determining that the state of the MBS session is a second state. Optionally, the first state is activated, the second state is deactivated, and the state of the MBS session is determined to be deactivated.

[0016] Optionally, the second message is a path switch request message, and the second confirmation message is a path switch request confirmation message.

[0017] Optionally, the second message includes first state information, and the first state information indicates whether the first state is activated or deactivated; or, the second message indicates the first state by whether it includes the first state information indication.

[0018] Optionally, the second confirmation message includes second state information, where the second state information indicates whether the second state is activated or deactivated; or, the second confirmation message indicates the second state by whether it includes the second state information.

[0019] In a fourth aspect, a communication method is provided, which can be executed by a core network device or a chip in the core network device. The method includes: receiving a second message from a second access network device; and sending a second confirmation message corresponding to the second message to the second access network device; wherein the second message indicates that the first state of the MBS session is activated or deactivated; and / or the second confirmation message indicates that the second state of the MBS session is activated or deactivated. This solution ensures normal MBS transmission during handover, avoids resource waste, and avoids behavioral mismatches caused by changes in the MBS session state during handover.

[0020] In combination with the fourth aspect, the status of the MBS session is activated, and the method also includes: receiving a first request message from a second access network device, where the first request message is used to request establishment of a user plane tunnel corresponding to the MBS session; or, the status of the MBS session is deactivated, and the method also includes: determining that there is currently no need to establish a user plane tunnel corresponding to the MBS session; or, the status of the MBS session is deactivated, and the method also includes: receiving a first request message from a second access network device, where the first request message is used to request establishment of a user plane tunnel corresponding to the MBS session, and the user plane tunnel is suspended.

[0021] In a fifth aspect, a communication method is provided, which can be executed by a second access network device or a chip in the second access network device. The method includes: sending a fourth message to a core network device, the fourth message being used to request the establishment of a user plane tunnel corresponding to an MBS session; receiving a fourth confirmation message corresponding to the fourth message from the core network device, the fourth confirmation message indicating whether the status of the MBS session is activated or deactivated. In this solution, the second access network device can learn about the core network device's management of the UP tunnel based on the fourth confirmation message. If the first status of the MBS session is activated, the second access network device can trigger a new UP tunnel to ensure normal transmission of the MBS during the switching process; if the first status of the MBS session is deactivated, the second access network device may not trigger a new UP tunnel or suspend the new UP tunnel to avoid resource waste.

[0022] Optionally, the fourth confirmation message includes information for establishing the user plane tunnel and indicates that the status of the MBS session is activated; or, the fourth confirmation message includes information for refusing to establish the user plane tunnel; or, the fourth confirmation message includes information for establishing the user plane tunnel and indicates that the status of the MBS session is deactivated.

[0023] In a sixth aspect, a communication method is provided, which can be executed by a core network device or a chip in the core network device. The method includes: receiving a fourth message from a second access network device, the fourth message being used to request establishment of a user plane tunnel corresponding to an MBS session; and sending a fourth confirmation message corresponding to the fourth message to the second access network device, the fourth confirmation message indicating whether the second state of the MBS session is activated or deactivated. In this solution, the second access network device can learn about the core network device's management of the UP tunnel based on the fourth confirmation message, thereby ensuring normal MBS transmission during the handover process and avoiding resource waste.

[0024] In a seventh aspect, a communication method is provided, which can be executed by a core network device or a chip within the core network device. The method includes: determining a first state of an MBS session; and sending third information to a first access network device, where the third information indicates the first state of the MBS session. This solution can be used to inform the first access network device of the MBS session state before handover, thereby clarifying MBS transmission operations and ensuring normal MBS transmission after subsequent handover.

[0025] Optionally, the third information is information contained in the MBS session change message; or, the third information is information contained in a first PDU session change message or establishment message, wherein the first PDU session is associated with the MBS session; or, the third information is information in an information field in the packet header of the data packet of the MBS service.

[0026] In an eighth aspect, a communication method is provided, which can be executed by a first access network device or a chip in the first access network device. The method includes: receiving third information, wherein the third information indicates a first state of the MBS session; and storing the MBS state information in the MBS context and / or in the context of the terminal device. This solution can be applied to the first access network device to obtain the MBS session state based on the third information before handover, thereby clarifying MBS transmission operations and ensuring normal MBS transmission after subsequent handover.

[0027] In a ninth aspect, a communication method is provided, which can be executed by a first access network device or a chip in the first access network device. The method includes: determining that the status of an MBS session is deactivated, and the MBS session is associated with a first PDU session; sending a fifth message to a core network device, the fifth message being used to request the release of the first PDU session, wherein the first PDU session is only used for the MBS session; or sending a fifth message to a core network device, the fifth message being used to request the deletion of information about the MBS session from the first PDU session, wherein the first PDU session is used to transmit unicast services, and / or the first PDU session is also associated with other activated MBS sessions. Through this solution, it is possible to avoid waste of resources caused by the deletion of a newly created UP tunnel before it is used.

[0028] In one implementation, the fifth message is used to request the release of the first PDU session, and the method further includes: releasing the RRC connection of the terminal device.

[0029] In another implementation, the fifth message is used to request that information about the MBS session be deleted from the first PDU session, and the method further includes: sending handover indication information to the terminal device, the handover indication information being used to instruct the terminal device to handover to a target cell, the target cell not supporting MBS sessions. The first access network device is a source access network device serving the terminal device.

[0030] In a tenth aspect, a communication method is provided, which can be executed by a core network device or a chip in the core network device. The method includes: receiving a fifth message from a first access network device, the fifth message being used to request the release of a first PDU session, wherein the first PDU session is only used for the MBS session; or receiving a fifth message from the first access network device, the fifth message being used to request the deletion of information about the MBS session from the first PDU session, wherein the first PDU session is used to transmit unicast services, and / or the first PDU session is also associated with other activated MBS sessions. The MBS session is in a deactivated state, and the MBS session is associated with the first PDU session.

[0031] In an eleventh aspect, a communication system is provided, which may include a first access network device and a second access network device. The second access network device may be used to perform the method in any possible implementation of the first aspect, and the first access network device may be used to perform the method in any possible implementation of the second aspect.

[0032] In a twelfth aspect, a communication system is provided, which may include a second access network device and a core network device. The second access network device may be used to perform the method in any possible implementation of the third aspect, and the core network device may be used to perform the method in any possible implementation of the fourth aspect; or the second access network device may be used to perform the method in any possible implementation of the fifth aspect, and the core network device may be used to perform the method in any possible implementation of the sixth aspect.

[0033] In a thirteenth aspect, a communication system is provided, which may include a first access network device and a core network device. The first access network device may be used to perform the method in any possible implementation of the eighth aspect, and the core network device may be used to perform the method in any possible implementation of the seventh aspect; or the first access network device may be used to perform the method in any possible implementation of the ninth aspect, and the core network device may be used to perform the method in any possible implementation of the tenth aspect.

[0034] In a fourteenth aspect, a communication system is provided, which may include a first access network device, a second access network device, and a core network device. The second access network device may be used to perform the method in any possible implementation of the first aspect, the third aspect, and / or the fifth aspect; the first access network device may be used to perform the method in any possible implementation of the second aspect and / or the eighth aspect; and the core network device may be used to perform the method in any possible implementation of the fourth aspect, the sixth aspect, and / or the seventh aspect.

[0035] In a fifteenth aspect, a communication device is provided, comprising modules or units for executing the method in any possible implementation of the first aspect, the third aspect, or the fifth aspect.

[0036] In the sixteenth aspect, a communication device is provided, comprising modules or units for executing the method in any possible implementation of the second aspect, the eighth aspect, or the ninth aspect.

[0037] In the seventeenth aspect, a communication device is provided, comprising modules or units for executing the method in any possible implementation of the fourth aspect, sixth aspect, seventh aspect, or tenth aspect.

[0038] In aspect 18, a communication device is provided, comprising a processor. The processor is coupled to a memory and is configured to execute instructions in the memory, causing the communication device to perform the method of any possible implementation of aspect 1, aspect 3, or aspect 5. Optionally, the communication device further comprises a memory. Optionally, the communication device further comprises a transceiver and / or an antenna. Optionally, the communication device may be a second access network device or a chip configured in the second access network device.

[0039] In a nineteenth aspect, a communication device is provided, comprising a processor. The processor is coupled to a memory and is configured to execute instructions in the memory, causing the communication device to perform the method of any possible implementation of the second aspect, the eighth aspect, or the ninth aspect. Optionally, the communication device further comprises a memory. Optionally, the communication device further comprises a transceiver and / or an antenna. Optionally, the communication device may be a first access network device or a chip configured in the first access network device.

[0040] In a twentieth aspect, a communications device is provided, comprising a processor. The processor is coupled to a memory and configured to execute instructions in the memory, causing the communications device to perform the method of any possible implementation of the fourth, sixth, seventh, or tenth aspects. Optionally, the communications device further comprises a memory. Optionally, the communications device may be a core network device or a chip configured in the core network device.

[0041] In aspect 21, an access network device is provided, which can implement the method in any possible implementation of aspect 1, aspect 3, or aspect 5, or the method in any possible implementation of aspect 2, aspect 8, or aspect 9. Optionally, the access network device can be a chip (such as a baseband chip or a communication chip) or a base station device, and can implement the method through software, hardware, or hardware executing corresponding software.

[0042] In one possible implementation, the access network device includes a processor and a memory. The processor is configured to support the access network device in executing the method described in any possible implementation of the first, third, or fifth aspects above; or the processor is configured to support the access network device in executing the method described in any possible implementation of the second, eighth, or ninth aspects above. The memory is configured to store instructions and / or data. Optionally, the access network device also includes a radio frequency unit and an antenna.

[0043] In another possible implementation, the access network device includes a baseband unit and a transceiver unit. The baseband unit is configured to execute the actions implemented within the access network device in any possible implementation method of the first, third, or fifth aspects, or the baseband unit is configured to execute the actions implemented within the access network device in any possible implementation method of the second, eighth, or ninth aspects. The transceiver unit is configured to execute the actions of the access network device sending to or receiving from the outside.

[0044] In another possible implementation, the access network device includes a processor and a transceiver. The processor is configured to support the access network device in executing the method described in any possible implementation of the first, third, or fifth aspects, or the processor is configured to support the access network device in executing the method described in any possible implementation of the second, eighth, or ninth aspects. When the access network device is a chip, the transceiver may be an input / output unit, such as an input / output circuit or an input / output interface.

[0045] In another possible implementation, the access network device may include a unit module that performs the corresponding actions in any possible implementation method of the above-mentioned first aspect, third aspect, or fifth aspect, or the access network device may include a unit module that performs the corresponding actions in any possible implementation method of the above-mentioned second aspect, eighth aspect, or ninth aspect.

[0046] In aspect 22, a core network device is provided, which can implement the method in any possible implementation of aspect 4, aspect 6, aspect 7, or aspect 10. Optionally, the core network device can be a chip (such as a baseband chip or a communication chip) or a core network device, and the method can be implemented through software, hardware, or hardware executing corresponding software.

[0047] In one possible implementation, the core network device includes a processor and a memory. The processor is configured to support the core network device in executing the method of any possible implementation of the fourth, sixth, seventh, or tenth aspects. The memory is configured to store instructions and / or data.

[0048] In another possible implementation, the core network device includes a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and execute the method in any possible implementation of the fourth aspect, sixth aspect, seventh aspect, or tenth aspect above.

[0049] In another possible design, the core network device includes a processing unit, wherein the processing unit can be used to perform some internal operations of the core network device. The functions performed by the processing unit can correspond to the operations involved in the fourth aspect, the sixth aspect, the seventh aspect, or the tenth aspect.

[0050] In another possible implementation, the core network device may include a unit module that performs corresponding actions in any possible implementation method of the fourth aspect, sixth aspect, seventh aspect, or tenth aspect.

[0051] In the twenty-third aspect, a computer-readable storage medium is provided, which stores a computer program or instruction, and when the computer program or instruction is executed, it implements the method in any possible implementation of the first aspect, the third aspect, or the fifth aspect mentioned above.

[0052] In the twenty-fourth aspect, a computer-readable storage medium is provided, storing a computer program or instruction, which, when executed, implements the method in any possible implementation of the second aspect, the eighth aspect, or the ninth aspect.

[0053] In the twenty-fifth aspect, a computer-readable storage medium is provided, storing a computer program or instruction, which, when executed, implements the method in any possible implementation of the fourth aspect, sixth aspect, seventh aspect, or tenth aspect.

[0054] In aspect 26, a processor is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive signals via the input circuit and transmit signals via the output circuit, so that the processor executes the method of any of the aforementioned aspects or any possible implementations of such aspects. Optionally, the processor is a chip, the input circuit is an input pin, the output circuit is an output pin, and the processing circuit is a transistor, a gate circuit, a trigger, and / or various logic circuits.

[0055] In aspect twenty-seven, a computer program product comprising a computer program or instructions is provided, which, when the computer program or instructions are executed, enables the computer to execute the method in any possible implementation of the above-mentioned first aspect, third aspect, or fifth aspect.

[0056] In aspect twenty-eight, a computer program product comprising a computer program or instructions is provided, which, when the computer program or instructions are executed, enables the computer to execute the method in any possible implementation of aspect two, aspect eight, or aspect nine.

[0057] In the twenty-ninth aspect, a computer program product comprising a computer program or instructions is provided, which, when the computer program or instructions are executed, enables the computer to execute the method in any possible implementation of the fourth aspect, sixth aspect, seventh aspect, or tenth aspect mentioned above. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 A schematic diagram of the communication system of this application;

[0059] Figure 2 A schematic diagram of a switching process provided by this application;

[0060] Figure 3A A schematic diagram of a switching scenario provided by this application;

[0061] Figure 3B A schematic diagram of another switching scenario provided by this application;

[0062] Figure 4 A flow chart of a communication method provided in this application;

[0063] Figure 5 A flow chart of another communication method provided by this application;

[0064] Figure 6 A flow chart of another communication method provided by this application;

[0065] Figure 7 A flow chart of another communication method provided by this application;

[0066] Figure 8 A flow chart of another communication method provided by this application;

[0067] Figure 9 A flow chart of another communication method provided by this application;

[0068] Figure 10 A flow chart of another communication method provided by this application;

[0069] Figure 11 A schematic structural diagram of the communication device provided in this application;

[0070] Figure 12 A schematic structural diagram of the communication device provided in this application;

[0071] Figure 13 A schematic structural diagram of the access network equipment provided for this application;

[0072] Figure 14 This is a schematic structural diagram of the core network equipment provided in this application. DETAILED DESCRIPTION

[0073] The technical solution in this application will be described below with reference to the accompanying drawings.

[0074] The methods and devices provided in the embodiments of the present application can be applied to various communication systems, for example, long term evolution (LTE) systems, fifth generation (5G) systems, new radio (NR) systems, wireless-fidelity (WiFi) systems, communication systems related to the third generation partnership project (3GPP), and other communication systems or multiple communication convergence systems that may appear in the future. The core network of the 4G system can be called the evolved packet core (EPC), and the access network can be called long term evolution (LTE). The core network of the 5G system can be called 5GC (5G core), and the access network can be called new radio. For the convenience of description, this application takes the 5G system as an example, but it can be understood that this application is also applicable to the 4G system, etc. The communication system in this application includes access network equipment, core network equipment and terminal equipment, which are described below.

[0075] An access network device is a network-side device with wireless transceiver functions. An access network device can be a device that provides wireless communication functions for terminal devices in a radio access network (RAN), and therefore, it can also be called a RAN device. For example, the access network device can be a base station, an evolved NodeB (eNodeB), a next-generation NodeB (gNB) in a 5G mobile communication system, a transmission reception point (TRP), a base station that has been subsequently evolved by 3GPP, an access node in a WiFi system, a wireless relay node, a wireless backhaul node, etc. In communication systems using different radio access technologies (RAT), the names of devices with base station functions may be different. For example, in an LTE system, it can be called an eNB or eNodeB, and in a 5G system or NR system, it can be called a gNB. This application does not limit the specific name of the base station. The access network device may include one or more co-located or non-co-located transmission and reception points. For another example, the access network device may include one or more centralized units (CU), one or more distributed units (DU), or one or more CUs and one or more DUs. For example, the functions of the CU may be implemented by one entity or different entities. For example, the functions of the CU are further divided, that is, the control plane and the user plane are separated and implemented by different entities, namely the control plane CU entity (i.e., CU-CP entity) and the user plane CU entity (i.e., CU-UP entity). The CU-CP entity and the CU-UP entity may be coupled with the DU to jointly complete the functions of the access network device. In this way, part of the functions of the wireless access network device may be implemented by multiple network function entities. These network function entities may be network elements in hardware devices, or software functions running on dedicated hardware, or virtualized functions instantiated on a platform (e.g., a cloud platform). For another example, in vehicle to everything (V2X) technology, the access network device may be a roadside unit (RSU). Multiple access network devices in a communication system may be base stations of the same type or different types. A base station may communicate with a terminal device or communicate with a terminal device through a relay station. In an embodiment of the present application, the device for implementing the function of the access network device may be the access network device itself, or it may be a device that can support the access network device to implement the function, such as a chip system or a combination of devices and components that can implement the function of the access network device. The device can be installed in the access network device.In the embodiment of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. In the embodiment of the present application, the access network device is taken as an example to describe the technical solution.

[0076] Core network equipment is used to implement functions such as mobility management, data processing, session management, policy and billing. The names of devices implementing core network functions in systems with different access technologies may vary, and this application does not limit this. Taking the 5G network as an example, the logical network elements of 5GC include: access and mobility management function (AMF), session management function (SMF), or user plane function (UPF). AMF is a network element used to manage access and mobility of terminal devices, mainly involving functions such as terminal device location update, network registration, and handover control. SMF is a network element used to manage sessions of terminal devices, mainly involving functions such as session establishment, modification, and release. UPF is a network element used to receive and forward user data. UPF is controlled by SMF. Different logical network elements of 5GC can be deployed on the same or different physical devices. For example, AMF and SMF can be deployed on the same physical device or on two physical devices. In addition, the logical network elements of 5GC can be deployed on the same physical device as the network elements of the 4G core network. The device for implementing the functions of the core network device can be the core network device, or it can be a device that can support the core network device to implement the functions, such as a chip system or a combination of devices or components that can implement the functions of the core network device. The device can be installed in the core network device. In the embodiments of the present application, the technical solution is described using the core network device as an example.

[0077] A terminal device is a user-side device with wireless transceiver capabilities. It can be a fixed device, mobile device, handheld device (such as a mobile phone), wearable device, in-vehicle device, or a wireless device built into any of the above devices (such as a communication module, modem, or chip system). Terminal devices are used to connect people, objects, and machines, and can be used in a wide range of scenarios, such as cellular communications, device-to-device (D2D) communications, vehicle-to-everything (V2X) communications, machine-to-machine / machine-type communications (M2M / MTC) communications, the Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, self-driving, remote medical, smart grid, smart furniture, smart office, smart wearables, smart transportation, smart city, drones, robots, and other scenarios. Exemplarily, the terminal device can be a handheld terminal in cellular communication, a communication device in D2D, an Internet of Things device in MTC, a surveillance camera in intelligent transportation and smart cities, or a communication device on a drone, etc. The terminal device may sometimes be referred to as user equipment (UE), user terminal, user device, user unit, user station, terminal, access terminal, access station, UE station, remote station, mobile device or wireless communication device, etc. In the embodiment of the present application, the device for realizing the function of the terminal device may be a terminal device, or a device that can support the terminal device to realize the function, such as a chip system or a combination device or component that can realize the function of the terminal device, and the device can be installed in the terminal device. In the embodiment of the present application, the technical solution is described by taking the terminal device as an example.

[0078] Figure 1 1 is a schematic diagram of a communication system applicable to the present application. The communication system 100 includes: a core network device 110, a first access network device 120, a second access network device 130, and a terminal device 140.

[0079] The core network device 110 receives the MBS from the server and sends the MBS to the access network device (the first access network device 120 or the second access network device 130 ).

[0080] The first access network device 120 can be referred to as a source access network device, such as a source gNB. Accordingly, the first cell served by the first access network device 120 can be referred to as a source cell. Before a terminal device 140 performs a cell handover, the first access network device 120 provides network services to the terminal device 140. For example, before the cell handover, the first access network device 120 receives an MBS from the core network device 110 and sends the MBS to the terminal device 140.

[0081] The second access network device 130 can be referred to as a target access network device, such as a target gNB. Accordingly, the second cell is served by the second access network device 130 and can be referred to as a target cell. After the terminal device 140 performs a cell handover, the second access network device provides network services to the terminal device 140. For example, after the cell handover, the second access network device 130 receives an MBS from the core network device 110 and sends the MBS to the terminal device 140.

[0082] The terminal device 140 is used to communicate with the access network device, receive data from the access network device, or send data to the access network device. For example, the terminal device 140 is used to receive MBS from the access network device. When the terminal device moves, as the signal strength of each cell changes, in order to prevent the communication quality from deteriorating due to the deterioration of the cell signal quality, it needs to switch from the first cell to the second cell. Figure 1 As shown, the terminal device is moving away from the first cell it is currently connected to. When the strength of the signal sent by the first access network device to the terminal device drops to a certain value, if the terminal device continues to reside in the first cell and is served by the first access network device, it will lead to a decrease in communication quality, failure to transmit services normally, and even disconnection. In order to ensure normal communication of the terminal device, if the terminal device determines that the signal strength of the second cell is greater than the signal strength of the first cell, the terminal device needs to report the event to the first access network device to trigger the first access network device to initiate a switching process to switch the terminal device from the first cell to the second cell.

[0083] For ease of understanding, some terms involved in this application are first explained. For ease of description, the terminal device will be described as UE in the following description.

[0084] 1. Multicast and broadcast service (MBS): MBS is a service transmitted to multiple UEs, such as live broadcast services, public safety services, and batch software update services. MBS can also be called multimedia broadcast multicast service (MBMS). The description information of the MBS includes description information of one or more MBS flows, where the description information of the MBS flow includes at least one of the following: the quality of service identifier (QFI) of the MBS flow, characteristic information of the MBS flow, and the quality of service (QoS) requirement of the MBS flow. Data packets of the MBS flow can be identified by a QoS flow identifier sequence number (QFISN) or a user plane general packet radio service (GPRS) tunneling protocol user plane (GTP-U) sequence number (GTP-U sequence number, GTP-USN).

[0085] 2. Unicast: At the core network level, unicast refers to sending service data to the UE through a protocol data unit (PDU) session. The unicast mode of MBS refers to sending MBS data to the UE through a PDU session, or sending MBS data to the UE through a UE-level user plane tunnel. It can be called the 5GC individual multicast broadcast service traffic delivery method (5G core individual MBS traffic delivery method), which can be referred to as the unicast mode later. Unicast services are services for a single UE. The unicast transmission mode (point-to-point, PTP) is mainly a mode of transmitting data packets on the air interface side for a single UE.

[0086] 3. Multicast / Broadcast: At the core network level, multicast / broadcast refers to sending MBS data to terminal devices through multicast / broadcast sessions, or sending MBS data to UEs through shared user plane tunnels. It can also be called the 5G core shared MBS traffic delivery method, and can be referred to as the multicast broadcast method later.

[0087] 4. Protocol data unit session (PDU session): PDU session provides data connectivity between UE and data network (DN). Therefore, before the UE sends data traffic, it should first establish a PDU session. The UE initiates the creation, and only after the core network accepts the UE's request and allocates the corresponding control plane and user plane resources can the UE transmit data between the DN. The PDU session is at the UE level, which means that a certain PDU session is only used for a certain UE. After a PDU session is established, a PDU session tunnel is established. The UE requests the core network to create a PDU session, and the core network can create one or more PDU sessions according to its business needs.

[0088] 5. Multicast Broadcast Session (MBS Session): An MBS session is used to transmit MBS services. MBS services can be transmitted between core network devices and access network devices via a common transmission channel, an MBS session. Each MBS session includes at least one MBS Quality of Service (QoS) flow. Unlike a PDU session, an MBS session is intended for multiple UEs. For a UE transmitting an MBS service via an MBS session, there is also a PDU session associated with the MBS session. This PDU session includes the QoS flow and MBS ID for the MBS service. This means that the QoS flow and MBS ID for the MBS service exist in the UE context. The PDU session associated with the MBS session can be any of the following: a PDU session containing only the QoS flow for the MBS service; a PDU session containing only multiple QoS flows for MBS services, one of which is the QoS flow for the MBS service; or a PDU session containing both the QoS flow for a unicast service and the QoS flow for the MBS service. MBS session states include activation and deactivation, which are triggered and managed by the core network. Regardless of the activation or deactivation state, the MBS information (QoS flow and MBS ID) included in the PDU session can still be saved in the UE context, thus avoiding the need for multiple modifications to add and delete MBS information during the activation and deactivation of the MBS session state changes.

[0089] 6. User plane tunnel (UP tunnel): This is also known as the GPRS Tunneling Protocol user plane (GTP-U) tunnel, used for data transmission between the core network's UPF network element and access network equipment. When activated, MBS can be transmitted through the UP tunnel corresponding to the MBS session. When deactivated, the UP tunnel corresponding to the MBS session is deleted. When the MBS session is reactivated, the corresponding tunnel can be re-established.

[0090] Figure 2 This is a handover (HO) process diagram. Figure 2 Briefly describe the switching process.

[0091] Prior to S201, the UE accesses the first access network device. Exemplarily, the UE resides in the first cell and enters a radio resource control (RRC) connected state. The core network device sends service data for the UE, such as MBS, to the first access network device. Accordingly, the first access network device receives the service data and sends it to the UE.

[0092] S201: A first access network device sends a measurement configuration parameter to a UE. Correspondingly, the UE receives the measurement configuration parameter from the first access network device.

[0093] The measurement configuration parameters include at least one of the following: measurement frequency / cell information, reporting threshold configuration, filter parameter configuration, timer duration configuration and other information.

[0094] S202: The UE in the RRC connected state sends a measurement report. Correspondingly, the first access network device receives the measurement report.

[0095] Exemplarily, the UE measures the signal strength of the frequency point or the cell according to the measurement configuration parameters to determine a measurement result; then, the UE determines and reports a measurement report according to the measurement result.

[0096] S203: The first access network device determines a second access network device based on the measurement report, the operation policy, or the PLMN supported by the UE. The second access network device is the access network device to which the UE is about to be handed over, such as the target base station; and the first access network device is the access network device currently serving the UE, such as the source base station.

[0097] S204: The first access network device sends a handover request message to the second access network device, and sends the UE context information along with the handover request message to the second access network device. Correspondingly, the second access network device receives the handover request message from the first access network device.

[0098] S205: The second access network device sends a handover request acknowledgement message to the first access network device. Correspondingly, the first access network device receives the handover request acknowledgement message from the second access network device.

[0099] Exemplarily, the second access network device determines that the UE can be allowed to access and sends a handover request confirmation message to the first access network device. Optionally, the handover request confirmation message includes at least one of the following: a cell radio network temporary identifier (C-RNTI) and a security algorithm of the second access network device.

[0100] S206: The first access network device sends an RRC reconfiguration message to the UE. Correspondingly, the UE receives the RRC reconfiguration message from the first access network device.

[0101] Optionally, the RRC reconfiguration message includes at least one of the following: a physical cell identifier (PCI) of the second cell, a new C-RNTI, a security algorithm identifier (security algorithm identifiers) of the second access network device, random access channel (RACH) resource information required for accessing the second cell (such as dedicated RACH resources and / or common RACH resources), and a system information block (SIB) of the second cell.

[0102] S207, the UE synchronizes to the second cell and sends an RRC reconfiguration complete message to the second access network device, indicating that the RRC handover is completed, that is, the RAN handover is completed.

[0103] S208: The second access network device sends a path switch request message to the core network device. Correspondingly, the core network device receives the path switch request message sent by the second access network device.

[0104] The path switching request message is used to trigger switching of the downlink data path to the second access network device and to establish a control plane interface between the core network device and the second access network device.

[0105] S209: The core network device switches the downlink data path to the second access network device.

[0106] S210: The core network device sends a path switch request acknowledgement message to the second access network device. Correspondingly, the second access network device receives the path switch request acknowledgement message sent by the core network device.

[0107] Optionally, the core network device in S208 and S210 is AMF.

[0108] In summary, the purpose of the path switching request is to request the core network to switch the termination point of (some) user plane transmission bearers of the UE under the first access network device to the second access network device, so that the core network can continue to transmit data to this UE through the second access network device.

[0109] S211: The second access network device sends a UE context release message to the first access network device. Correspondingly, the first access network device receives the UE context release message sent by the second access network device.

[0110] The release message indicates that the handover is successful. Furthermore, the first access network device releases the radio resources and control plane resources associated with the context of the UE.

[0111] The present application embodiment involves two switching scenarios, wherein the scenario is as follows: Figure 3A As shown, scene 2 is as Figure 3B As shown. In the embodiment of the present application, the access network device that supports MBS sessions can be called an MBS access network device, the cell served by the MBS access network device can be called an MBS cell, and the MBS is transmitted between the core network device and the MBS access network device via an MBS session. In the embodiment of the present application, the access network device that does not support MBS sessions can be called a non-MBS access network device, such as a legacy base station, the cell served by the non-MBS access network device can be called a non-MBS cell, and the MBS is transmitted between the core network device and the non-MBS access network device via a unicast PDU session.

[0112] (1) Scenario 1

[0113] The first access network device is an MBS access network device. Before the UE is handed over to the second cell, the first access network device has an MBS that the UE is currently transmitting or interested in. The second access network device is also an MBS access network device. However, before the UE is handed over to the second cell, the second access network device does not have an MBS that the UE is currently transmitting or interested in. The second cell is the serving cell of the second access network device.

[0114] In scenario 1, the second access network device doesn't have the MBS session required by the UE before the handover and isn't aware of the MBS session status. Therefore, upon discovering a PDU session containing MBS information, the second access network device triggers the core network device to establish an UP tunnel for the MBS session to transmit MBS data. However, if the MBS session is currently deactivated (meaning there's no MBS data to transmit), the newly created UP tunnel will be deleted after a period of time. This unused UP tunnel is then deleted, wasting resources and rendering it useless.

[0115] (2) Scenario 2

[0116] The first access network device is an MBS access network device, and the second access network device is a non-MBS access network device.

[0117] In scenario two, the second access network device cannot identify the MBS session and its status, so the second access network device triggers the core network device to establish an UP tunnel for the PDU session associated with the MBS session for transmitting MBS data. However, if the current status of the MBS session is deactivated, and the PDU session associated with the MBS session only contains the QoS flow of the MBS, then after a period of time, the newly created UP tunnel will be deleted because there is no MBS data. In other words, the newly created UP tunnel is deleted before it is used, wasting resources and being useless. If the current status of the MBS session is deactivated, and the PDU session associated with the MBS session contains the QoS flow of the MBS and the QoS flows of other services, then redundant messages will be introduced in the process of creating a new UP tunnel, such as the QoS flow information associated with the MBS session, which wastes signaling resources and is useless.

[0118] To solve the above technical problems, the method provided by the embodiment of the present application is described below in conjunction with the accompanying drawings. It can be understood that the method embodiments described below are only described by taking the execution subjects as core network devices, access network devices and terminal devices as examples. The core network devices mentioned in the method embodiments can also be replaced by chips configured in the core network devices. The access network devices mentioned in the method embodiments can also be replaced by chips configured in the access network devices. The terminal devices can also be replaced by chips configured in the terminal devices. The core network devices, access network devices and terminal devices can specifically be the various forms mentioned above. For example, the access network device can be a base station, CU or CU-CP, etc., which have RRC connection control functions. For example, the core network device can be a device with AMF functions, or a device with AMF functions and UPF functions, or the core network device can be a device with AMF functions and SMF functions, or the core network device can be a device with AMF functions, UPF functions and SMF functions.

[0119] Figure 4 This is a flow chart of a communication method provided in Example 1 of this application. Figure 4 As shown, the communication system provided in the first embodiment includes: a first access network device and a second access network device, wherein the first access network device can be used to execute the method in any possible implementation of the first embodiment, and the second access network device can be used to execute the method in any possible implementation of the first embodiment. Figure 3A Taking scenario 1 as an example, a possible implementation is described. The method includes the following steps.

[0120] S401: A first access network device sends a first message. Correspondingly, a second access network device receives the first message, wherein the first message indicates that a first state of an MBS session is activation or deactivation.

[0121] S402: The second access network device sends a first confirmation message. Correspondingly, the first access network device receives the first confirmation message, wherein the first confirmation message is a confirmation message corresponding to the first message.

[0122] MBS is a service that the UE is interested in or is currently receiving. The first state is the state of the MBS session before the UE is switched, that is, the state of the MBS session notified by the core network device to the first access network device before the UE is switched.

[0123] Optionally, the MBS context managed by the first access network device includes the first state of the MBS session. After the first access network device learns the MBS state from the core network device, it can save the MBS state information for subsequent use. The information is saved in the MBS context and / or the UE context.

[0124] Optionally, the second access network device saves the state of the MBS session to the MBS context and / or the UE context.

[0125] The first message indicates a first state of the MBS session, specifically method 1, method 2, or method 3:

[0126] Method 1: The first message includes first state information, where the first state information indicates whether the first state is activated or deactivated.

[0127] Method 2: The first message indicates the first state by whether it includes first state information. For example, if the first message includes the first state information, the first message indicates that the first state is activated; or if the first message does not include the first state information, the first message indicates that the first state is deactivated. Optionally, the first state information is activation information for the MBS session.

[0128] Method 3: The first message indicates the first state by whether it includes first state information. For example, if the first message includes first state information, the first message indicates that the first state is deactivated; or if the first message does not include first state information, the first message indicates that the first state is activated. Optionally, the first state information is deactivation information for the MBS session.

[0129] Optionally, the first message is a handover request message, and the first confirmation message is a handover request confirmation message. In order to indicate the first state of the MBS session, a new information element (IE) needs to be added to the existing handover request message.

[0130] Optionally, the first message is a new message, and the first confirmation message is also a new message. For example, the first message is newly introduced to indicate the first state of the MBS session.

[0131] As a possible implementation manner, after step S401, the method further includes: the second access network device obtains, according to the first message, a state of the MBS session as a first state.

[0132] The state of the MBS session is active, and the second access network device sends a first request message to the core network device, wherein the first request message is used to request establishment of a UP tunnel corresponding to the MBS session. Accordingly, the core network device receives the first request message sent by the second access network device.

[0133] If the MBS session is in the deactivated state, the second access network device handles the situation in one of the following two ways: First, the second access network device determines that there is no need to establish the UP tunnel corresponding to the MBS session. Specifically, the second access network device determines that there is no need to request the core network device to establish the UP tunnel corresponding to the MBS session. Then, after the MBS session is activated, it requests to establish the UP tunnel. Accordingly, the core network device determines that there is no need to establish the UP tunnel corresponding to the MBS session. Specifically, the core network device does not receive the message from the second access network device requesting to establish the UP tunnel. Second, the second access network device sends a first request message to the core network device requesting to establish the UP tunnel corresponding to the MBS session, suspending the UP tunnel. It is understood that before the MBS session is activated, the UP tunnel is suspended, or in a deactivated state. This means that the UP tunnel is retained and not used to transmit MBS data. When the MBS session is subsequently activated, the UP tunnel can continue to be used, avoiding the UP tunnel deletion process. Correspondingly, the core network device receives the message sent by the second access network device requesting to establish the UP tunnel.

[0134] The first message indicates the first state of the MBS session. The second access network device can determine whether to request the core network to establish a UP tunnel based on the first state. If the first state of the MBS session is active, the second access network device can trigger a new UP tunnel to ensure normal MBS transmission during the handover process. If the first state of the MBS session is deactivated, the second access network device may not trigger a new UP tunnel or request a new pending UP tunnel to avoid wasting resources.

[0135] Figure 5 This is a flow chart of a communication method provided in Example 2 of this application. Figure 5 As shown, the communication system provided in the second embodiment includes: a second access network device and a core network device, wherein the second access network device can be used to execute the method in any possible implementation of this embodiment, and the core network device can be used to execute the method in any possible implementation of this embodiment. Figure 3A Taking scenario 1 as an example, a possible implementation is described. The method includes the following steps.

[0136] S501: A second access network device sends a second message, and a core network device receives the second message accordingly.

[0137] S502: The core network device sends a second confirmation message. Correspondingly, the second access network device receives the second confirmation message, wherein the second confirmation message is a confirmation message corresponding to the second message.

[0138] The second message indicates that the first state of the MBS session is activated or deactivated, wherein, for the description of the first state, please refer to Example 1 and will not be repeated here; and / or, the second confirmation message indicates that the second state of the MBS session is activated or deactivated, wherein the second state is the state of the MBS session after the UE is switched, that is, the core network device notifies the second access network device of the state of the MBS session through the second confirmation message after the UE is switched.

[0139] The second message indicates the first state of the MBS session, specifically method 1, method 2, or method 3 as follows:

[0140] Method 1: The second message includes first state information, where the first state information indicates whether the first state is activated or deactivated.

[0141] Method 2: The second message indicates the first state by whether it includes the first state information. For example, if the second message includes the first state information, the second message indicates that the first state is activated; or if the second message does not include the first state information, the second message indicates that the first state is deactivated. Optionally, the first state information is activation information for the MBS session.

[0142] Method 3: The second message indicates the first state by whether it includes the first state information. For example, if the second message includes the first state information, the second message indicates that the first state is deactivated; or if the second message does not include the first state information, the second message indicates that the first state is activated. Optionally, the first state information is deactivation information for the MBS session.

[0143] The second confirmation message indicates the second state of the MBS session, specifically method 1, method 2 or method 3 as follows:

[0144] Method 1: The second confirmation message includes second state information, where the second state information indicates whether the second state is activated or deactivated.

[0145] Method 2: The second confirmation message indicates the second state by whether it includes the second state information. For example, if the second confirmation message includes the second state information, the second confirmation message indicates that the second state is activated; alternatively, if the second confirmation message does not include the second state information, the second confirmation message indicates that the second state is deactivated. Optionally, the second state information is activation information for the MBS session.

[0146] Method 3: The second confirmation message indicates the second state by whether it includes the second state information. For example, if the second confirmation message includes the second state information, the second confirmation message indicates that the second state is deactivated; or if the second confirmation message does not include the second state information, the second confirmation message indicates that the second state is activated. Optionally, the second state information is deactivation information for the MBS session.

[0147] In a possible implementation, the second confirmation message indicates that the second state of the MBS session is activation or deactivation. Optionally, after S502, the second access network device obtains that the state of the MBS session is the second state.

[0148] In another possible implementation, the second message indicates whether the first state of the MBS session is activated or deactivated. Optionally, before S501, the second access network device obtains the first state of the MBS session. After receiving the second message, if the core network finds that the current state of the MBS session is the first state, the second confirmation message may not carry information indicating the second state, or the second confirmation message may confirm that the current state of the MBS session is the first state.

[0149] In another possible implementation, the second message indicates that the first state of the MBS session is activation or deactivation, and the second confirmation message indicates that the second state of the MBS session is activation or deactivation. Optionally, after S502, the second access network device determines that the state of the MBS session is the second state. For example, if the first state is activation and the second state is deactivation, the second access network device determines that the state of the MBS session is deactivation.

[0150] Optionally, the second message is a path switch request message, and the second confirmation message is a path switch request confirmation message. To indicate the first state of the MBS session, a new information element needs to be added to the existing path switch request message, and / or to indicate the second state of the MBS session, a new information element needs to be added to the existing path switch request confirmation message.

[0151] Optionally, the second message is a new message, and the second confirmation message is also a new message. For example, the second message is newly introduced to indicate the first state of the MBS session, and / or the second confirmation message is newly introduced to indicate the second state of the MBS session.

[0152] The state of the MBS session is active, and the second access network device sends a first request message to the core network device, wherein the first request message is used to request establishment of a UP tunnel corresponding to the MBS session. Accordingly, the core network device receives the first request message sent by the second access network device.

[0153] The state of the MBS session is deactivated. The processing method of the second access network device can refer to the description of the first embodiment and will not be repeated here.

[0154] Through the second message and / or the second confirmation message, the second access network device can learn the status of the MBS session. If the status of the MBS session is activated, the second access network device can trigger a new UP tunnel to ensure the normal transmission of the MBS during the switching process; if the status of the MBS session is deactivated, the second access network device may not trigger a new UP tunnel or request a new suspended UP tunnel to avoid resource waste.

[0155] During the handover process, the state of an MBS session may change. That is, the first state may differ from the second state. If the first state is still processed, this will cause behavior mismatches due to the MBS session state change. For example, if an MBS session changes from active to deactivated, if the first access network device still processes it as active, it will result in resource waste. For example, if an MBS session changes from deactivated to active, if the first access network device still processes it as deactivated, it will result in failure to establish a UP tunnel and prevent MBS data from being received properly. The method of this embodiment can avoid behavior mismatches due to MBS session state changes.

[0156] Figure 5 This is a flow chart of a communication method provided in Example 3 of this application. Figure 5 As shown, the communication system provided in the third embodiment includes: a second access network device and a core network device, wherein the second access network device can be used to execute the method in any possible implementation of this embodiment, and the core network device can be used to execute the method in any possible implementation of this embodiment. Figure 3A Taking scenario 1 as an example, a possible implementation is described. The method includes the following steps.

[0157] S501: A second access network device sends a fourth message. Correspondingly, a core network device receives the fourth message. The fourth message is used to request establishment of a user plane tunnel corresponding to an MBS session, that is, the user plane tunnel is used for data transmission of the MBS session.

[0158] S502: The core network device sends a fourth confirmation message. Correspondingly, the second access network device receives the fourth confirmation message. The fourth confirmation message is a confirmation message corresponding to the fourth message. The fourth confirmation message indicates whether the second state of the MBS session is activated or deactivated.

[0159] The second state is the state of the MBS session after the UE is switched, that is, the core network device notifies the second access network device of the second state of the MBS session through the fourth confirmation message after the UE is switched.

[0160] Optionally, the fourth confirmation message includes information for establishing a user plane tunnel and indicates that the second state of the MBS session is activated.

[0161] Optionally, the fourth confirmation message includes information of rejecting the establishment of the user plane tunnel. At this time, the state of the MBS session may be deactivated to avoid resource waste caused by creating a new tunnel and then releasing it.

[0162] Optionally, the fourth confirmation message includes information about establishing the user plane tunnel and indicates that the MBS session is in a deactivated state. At this point, the UP tunnel is suspended or deactivated, meaning it is retained but not used to transmit MBS data. The benefit of retaining the UP tunnel is that it can continue to be used when the MBS session is subsequently reactivated, avoiding the processes associated with UP tunnel deletion and re-establishment, saving signaling overhead, and avoiding delays associated with UP tunnel re-establishment.

[0163] In scenario 1, the second access network device can learn about the core network device's management of the UP tunnel based on the fourth confirmation message. If the first state of the MBS session is deactivated, the second access network device may not trigger a new UP tunnel or suspend the newly created UP tunnel to avoid wasting resources. If the first state of the MBS session is activated, the second access network device may trigger a new UP tunnel to ensure normal MBS transmission during the handover process.

[0164] Based on the solutions of Example 2 and Example 3, Figure 6 This is a flow chart of a detailed communication method provided in Example 4 of this application. Figure 6 As shown, the communication system provided by the fourth embodiment includes: a second access network device and a core network device, wherein the second access network device can be used to execute the method in any possible implementation of this embodiment, and the core network device can be used to execute the method in any possible implementation of this embodiment. Figure 3A The scenario 1 shown is used as an example to describe a possible implementation. It should be noted that the description of the fourth embodiment can refer to the description of the second and third embodiments, and the same parts will not be repeated. The method includes the following steps.

[0165] S601: A second access network device sends a second message, and a core network device receives the second message accordingly.

[0166] S602: The core network device sends a second confirmation message. Correspondingly, the second access network device receives the second confirmation message, wherein the second confirmation message is a confirmation message corresponding to the second message.

[0167] The second message indicates the first state of the MBS session, and / or the second confirmation message indicates the second state of the MBS session. Optionally, the second message is a path switch request message, and the second confirmation message is a path switch request confirmation message.

[0168] The detailed description of S601 and S602 is given in Example 2 and will not be repeated here.

[0169] S603: The second access network device sends a fourth message. Correspondingly, the core network device receives the fourth message. The fourth message is used to request establishment of a user plane tunnel corresponding to the MBS session.

[0170] S604: The core network device sends a fourth confirmation message. Accordingly, the second access network device receives the fourth confirmation message. The fourth confirmation message is a confirmation message corresponding to the fourth message. The fourth confirmation message indicates whether the second state of the MBS session is activated or deactivated.

[0171] The detailed description of S603 and S604 is given in Example 3 and will not be repeated here.

[0172] Exemplarily, the second message indicates that the first state of the MBS session is active, the fourth message requests establishment of a UP tunnel associated with the MBS session, and the fourth confirmation message includes information for establishing the UP tunnel and indicates that the second state of the MBS session is active.

[0173] Exemplarily, the second message indicates that the first state of the MBS session is activated, the fourth message requests establishment of a UP tunnel associated with the MBS session, and the fourth confirmation message includes information for refusing to establish the user plane tunnel, or the fourth confirmation message includes information for establishing the UP tunnel and indicates that the state of the MBS session is deactivated, and the UP tunnel is suspended.

[0174] Exemplarily, the second confirmation message indicates that the second state of the MBS session is active, the fourth message requests establishment of a UP tunnel associated with the MBS session, and the fourth confirmation message includes information for establishing the UP tunnel and indicates that the second state of the MBS session is active.

[0175] Exemplarily, the second message indicates that the first state of the MBS session is deactivated, the second confirmation message indicates that the second state of the MBS session is activated, the fourth message requests establishment of a UP tunnel associated with the MBS session, and the fourth confirmation message includes information for establishing the UP tunnel and indicates that the second state of the MBS session is activated.

[0176] During the handover process, the MBS session state may change. Multiple interactions between the second access network device and the core network device regarding the MBS session state, along with clear UP tunnel establishment behavior, can avoid behavior mismatches caused by MBS session state changes. If the MBS session state is active, a new UP tunnel can be established between the second access network device and the core network device to ensure normal MBS transmission during the handover process.

[0177] Based on the solutions of embodiment 1, embodiment 2, embodiment 3, and / or embodiment 4, Figure 7 This is a flow chart of a detailed communication method provided in Example 5 of this application. Figure 7 As shown, the communication system provided in Example 5 includes: a first access network device, a second access network device and a core network device, wherein the first access network device can be used to execute the method in any possible implementation of this embodiment, the second access network device can be used to execute the method in any possible implementation of this embodiment, and the core network device can be used to execute the method in any possible implementation of this embodiment. Figure 7 The steps indicated by dotted lines are optional and will not be described in detail in the following text. Figure 3A The scenario 1 shown is used as an example to describe a possible implementation. It should be noted that the description of the fifth embodiment can refer to the description of the first, second, third and fourth embodiments, and the same parts will not be repeated. The method includes the following steps.

[0178] S701: A core network device determines a first state of an MBS session.

[0179] The state of the MBS session is managed by the core network, that is, the state changes of the MBS session are all triggered by the core network. The description of the first state is shown in Example 1, which will not be repeated here.

[0180] S702: The core network device sends third information. Correspondingly, the first access network device receives the third information. The third information indicates the first state of the MBS session.

[0181] Optionally, the third information is information included in the MBS session change message; or, the third information is information in an information field in a packet header of a data packet of the MBS service.

[0182] Optionally, the third information is information contained in a first PDU session change message or an establishment message, wherein the first PDU session is associated with the MBS session. The UE notifies the first access network device of the service that the UE is interested in, or applies to join the MBS session (MBS session join), so that the first access network device determines to send the MBS data to the UE. After the first access network device receives the UE's request to join the MBS, it will establish and allocate corresponding resources for the UE for subsequent MBS transmission, such as the first PDU session for transmitting the MBS. When the UE joins the MBS session, the status of the MBS session can be in an activated or deactivated state. Therefore, the core network can notify the first access network device of the status of the MBS session through a first PDU session change message or an establishment message.

[0183] After receiving the third message, the first access network device can obtain the status of the MBS session and further clarify the operation of MBS transmission. Furthermore, the first access network device can save the MBS status information in the MBS context and / or the UE context.

[0184] It should be noted that S701 and S702 are also applicable to non-switching scenarios.

[0185] S703, the first access network device determines to switch the UE to the cell served by the second access network device according to the measurement report sent by the UE. Figure 2 The switching process shown will not be repeated here.

[0186] S704: The first access network device sends a first message. Correspondingly, the second access network device receives the first message, wherein the first message indicates that the first state of the MBS session is activation or deactivation.

[0187] S705: The second access network device sends a first confirmation message. Correspondingly, the first access network device receives the first confirmation message, wherein the first confirmation message is a confirmation message corresponding to the first message.

[0188] Optionally, the first message is a handover request message, and the first confirmation message is a handover request confirmation message.

[0189] S706: The core network device determines a second state of the MBS session. The second state is the state of the MBS session after the UE is switched, and details are as described in the above embodiment.

[0190] As a first possible implementation manner, this embodiment includes steps S707 and S708.

[0191] S707: The second access network device sends a second message. Correspondingly, the core network device receives the second message.

[0192] S708: The core network device sends a second confirmation message. Correspondingly, the second access network device receives the second confirmation message, wherein the second confirmation message is a confirmation message corresponding to the second message.

[0193] The second message indicates the first state of the MBS session, and / or the second confirmation message indicates the second state of the MBS session. Optionally, the second message is a path switch request message, and the second confirmation message is a path switch request confirmation message.

[0194] The detailed description of S707 and S708 is given in Example 2 and will not be repeated here.

[0195] As a second possible implementation manner, this embodiment includes steps S709 and S710.

[0196] S709: The second access network device sends a fourth message. Correspondingly, the core network device receives the fourth message. The fourth message is used to request establishment of a user plane tunnel corresponding to the MBS session.

[0197] S710: The core network device sends a fourth confirmation message. Accordingly, the second access network device receives the fourth confirmation message. The fourth confirmation message is a confirmation message corresponding to the fourth message. The fourth confirmation message indicates whether the second state of the MBS session is activated or deactivated.

[0198] The detailed description of S709 and S710 is given in Example 3 and will not be repeated here.

[0199] As a third possible implementation manner, this embodiment includes steps S707, S708, S709 and S710. For detailed description, please refer to the fourth embodiment, which will not be repeated here.

[0200] During the handover process, the status of the MBS session is unclear, and the behavior of the second access network device and the core network device is unclear. This embodiment provides a complete process for MBS session status interaction and how to establish an UP tunnel. Through the method of this embodiment, the behavior of the second access network device and the core network device is clarified; if the MBS session status is activated, a new UP tunnel can be created between the second access network device and the core network device to ensure the normal transmission of the MBS during the handover process; if the MBS session status is deactivated, the second access network device may not trigger the creation of a new UP tunnel or request a new suspended UP tunnel to avoid resource waste. In addition, through multiple interactions between the second access network device and the core network device on the MBS session status and the clear behavior of establishing the UP tunnel, the behavior mismatch problem caused by changes in the MBS session status during the handover process can be solved.

[0201] Based on the solutions of embodiment 1, embodiment 2, embodiment 3, and / or embodiment 4, Figure 8 This is a flow chart of a detailed communication method provided in Example 6 of this application. Figure 8 As shown, the communication system provided in Example 6 includes: a first access network device, a second access network device and a core network device, wherein the first access network device can be used to execute the method in any possible implementation of this embodiment, the second access network device can be used to execute the method in any possible implementation of this embodiment, and the core network device can be used to execute the method in any possible implementation of this embodiment. Figure 8 The steps indicated by dotted lines are optional and will not be described in detail in the following text. Figure 3AScenario 1 is used as an example to describe a possible implementation. It should be noted that the descriptions of Embodiments 1, 2, 3, and 4 can be referenced for Embodiments 6, and the common parts will not be repeated here. Compared to Embodiment 5, in this embodiment, the access network device serving the UE switches from the first access network device to the second access network device, which requires passing through the core network. The method includes the following steps.

[0202] S801: A core network device determines a first state of an MBS session.

[0203] S802: The core network device sends third information. Correspondingly, the first access network device receives the third information. The third information indicates the first state of the MBS session.

[0204] S803: The first access network device determines to hand over the UE to a cell served by the second access network device according to the measurement report sent by the UE.

[0205] The detailed description of S801, S802 and S803 is given in Example 5 and will not be repeated here.

[0206] S804: The first access network device sends a first handover request message. Correspondingly, the core network device receives the first handover request message. The first handover request message instructs the UE to be handed over to a cell served by the second access network device.

[0207] S805: The core network device sends a second handover request message. Accordingly, the second access network device receives the second handover request message. The second handover request message instructs the UE to be handed over to a cell served by the second access network device. The second handover request message further indicates whether the first state of the MBS session is activated or deactivated.

[0208] The first handover request message and the second handover request message are different messages, but both indicate handover of the UE to a cell served by the second access network device. The second handover request message indicates the first state of the MBS session. For details, refer to Method 1, Method 2, or Method 3 in Embodiment 1 where the first message indicates the first state of the MBS session, and are not further described here.

[0209] S806: The second access network device sends a second handover request confirmation message. Correspondingly, the core network device receives the second handover request confirmation message, wherein the second handover request confirmation message is a confirmation message of the second handover request message.

[0210] S807: The core network device sends a first handover request confirmation message. Correspondingly, the first access network device receives the first handover request confirmation message. The first handover request confirmation message is a confirmation message of the first handover request message.

[0211] S808: The core network device determines the second state of the MBS session. Detailed description is given in Embodiment 5, which will not be repeated here.

[0212] As a first possible implementation manner, this embodiment includes steps S809 and S810.

[0213] S809: The second access network device sends a second message. Correspondingly, the core network device receives the second message.

[0214] S810: The core network device sends a second confirmation message. Correspondingly, the second access network device receives the second confirmation message, wherein the second confirmation message is a confirmation message of the second message.

[0215] The second message indicates the first state of the MBS session, and / or the second confirmation message indicates the second state of the MBS session. Optionally, the second message is a path switch request message, and the second confirmation message is a path switch request confirmation message.

[0216] The detailed description of S809 and S810 is given in Example 2 and will not be repeated here.

[0217] As a second possible implementation manner, this embodiment includes steps S811 and S812.

[0218] S811: The second access network device sends a fourth message. Correspondingly, the core network device receives the fourth message, wherein the fourth message is used to request establishment of a user plane tunnel corresponding to the MBS session.

[0219] S812: The core network device sends a fourth confirmation message. Accordingly, the second access network device receives the fourth confirmation message. The fourth confirmation message is a confirmation message of the fourth message. The fourth confirmation message indicates whether the second state of the MBS session is activated or deactivated.

[0220] The detailed description of S811 and S812 is given in Example 3 and will not be repeated here.

[0221] As a third possible implementation manner, this embodiment includes steps S809, S810, S811 and S812. For detailed description, please refer to the fourth embodiment, which will not be repeated here.

[0222] During the handover process, the status of the MBS session is unclear, and the behavior of the second access network device and the core network device is unclear. This embodiment provides a complete process for MBS session status interaction and how to establish an UP tunnel. Through the method of this embodiment, the behavior of the second access network device and the core network device is clarified; if the MBS session status is activated, a new UP tunnel can be created between the second access network device and the core network device to ensure the normal transmission of the MBS during the handover process; if the MBS session status is deactivated, the second access network device may not trigger the creation of a new UP tunnel or request a new suspended UP tunnel to avoid resource waste. In addition, through multiple interactions between the second access network device and the core network device on the MBS session status and the clear behavior of establishing the UP tunnel, the behavior mismatch problem caused by changes in the MBS session status during the handover process can be solved.

[0223] Figure 9 This is a flow chart of a communication method according to the seventh embodiment of the present application. Figure 9 As shown, the communication system provided by this embodiment includes: a first access network device and a core network device, wherein the first access network device can be used to execute the method in any possible implementation of this embodiment, and the core network device can be used to execute the method in any possible implementation of this embodiment. Figure 9 The steps indicated by dotted lines are optional and will not be described in detail in the following text. Figure 3B Taking scenario 2 as an example, a possible implementation is described. The method includes the following steps.

[0224] S901: A first access network device determines that the status of an MBS session is deactivated, and the MBS session is associated with a first PDU session, wherein the first PDU session is only used for the MBS session.

[0225] The first PDU session is a PDU session configured for the terminal device, and the first PDU session is only used for the MBS.

[0226] Even if the MBS session is deactivated, the MBS ID and QoS flow still exist in the first PDU session.

[0227] Optionally, before S901 , S701 , S702 and S703 in the fifth embodiment may also be included.

[0228] As a first possible implementation, the core network notifies the first access network device to delete the first PDU session. Therefore, this embodiment includes steps S902 and S903. Optionally, after releasing the first PDU session, the first access network device replies to the core network device, which also includes S905.

[0229] S902: The first access network device sends a fifth message to the core network device. Correspondingly, the core network device receives the fifth message. The fifth message is used to request the release of the first PDU session, or in other words, the fifth message includes a release request message for the first PDU session.

[0230] Optionally, the fifth message further includes a release reason (cause value), for example, because the UE is to be handed over to a non-MBS base station, MBS related information needs to be released.

[0231] S903: The core network device sends a fifth confirmation message corresponding to the fifth message. Correspondingly, the first access network device receives the fifth confirmation message of the fifth message sent by the core network device. The fifth confirmation message includes release information of the first PDU session.

[0232] Before or at the same time as S903 , the process further includes: the core network device releasing the first PDU session, for example, resources occupied by the first PDU session.

[0233] S904: The first access network device releases the first PDU session, for example, the resources occupied by the first PDU session.

[0234] As a second possible implementation, the first access network device notifies the core network device after deleting the first PDU session. Therefore, this embodiment includes step S905. Optionally, the core network device may reply with a confirmation message, which also includes S906.

[0235] S905: The first access network device sends a release message for the first PDU session. Correspondingly, the core network device receives the release message for the first PDU session.

[0236] S906: The core network device sends a release confirmation message of the first PDU session. Correspondingly, the first access network device receives the release confirmation message of the first PDU session.

[0237] S907: The first access network device releases the RRC connection of the UE. Accordingly, the UE receives an RRC release message.

[0238] Because the UE does not have a PDU session and cannot perform HO, the UE can enter the RRC idle state (idle) / inactive state (inactive). At this time, there are two optional methods: the first is step S907, notifying the UE to enter the RRC idle state / inactive state. The second is that the UE enters the RRC idle state / inactive state on its own. The RRC idle state / inactive state can be determined by the configuration information received by the UE, such as cell-level configuration information, or NAS non-accessstratum non-access stratum information received by the UE about releasing the PDU session. After entering the RRC idle state / inactive state, the UE can perform cell selection, reselection and other behaviors to meet its mobility requirements.

[0239] Before the UE undergoes HO, the MBS session of the MBS service that the UE is interested in has been deactivated. However, the MBS ID and QoS flow still exist in the PDU session of the UE. Therefore, after the HO occurs, the second access network device will establish an UP tunnel and the corresponding DRB for the MBS ID that the UE is interested in. If the current status of the MBS session is deactivated, and the PDU session associated with the MBS session only contains the QoS flow of the MBS, then after a period of time, the newly created UP tunnel will be deleted because there is no MBS data, that is, the newly created UP tunnel is deleted before it is used, which wastes resources and is useless. The method of this embodiment can avoid the waste of resources caused by the newly created UP tunnel being deleted before it is used.

[0240] Figure 10 This is a flow chart of a communication method according to the eighth embodiment of the present application. Figure 10 As shown, the communication system provided by this embodiment includes: a first access network device and a core network device, wherein the first access network device can be used to execute the method in any possible implementation of this embodiment, and the core network device can be used to execute the method in any possible implementation of this embodiment. Figure 10 The steps indicated by dotted lines are optional and will not be described in detail in the following text. Figure 3B Taking scenario 2 as an example, a possible implementation is described. The method includes the following steps.

[0241] S1001: A first access network device determines that the status of an MBS session is deactivated, and the MBS session is associated with a first PDU session, wherein the first PDU session is used to transmit a unicast service and / or the first PDU session is also associated with other activated MBS sessions.

[0242] The first PDU session is a PDU session configured for the terminal device. The first PDU session is used for the MBS. The first PDU session is also used for unicast services and / or other activated MBS sessions.

[0243] Optionally, before S1001, S701, S702 and S703 in the fifth embodiment may also be included.

[0244] As a first possible implementation, the core network notifies the first access network device to modify the first PDU session. Therefore, this embodiment includes steps S1002 and S1003. Optionally, after modifying the first PDU session, the first access network device replies to the core network device, which also includes S1005.

[0245] S1002, the first access network device sends a fifth message to the core network device, where the fifth message is used to request deletion of the information of the MBS session from the first PDU session, or in other words, the fifth message includes a modification request message of the first PDU session, where the modification request message requests deletion of the information of the MBS session.

[0246] Optionally, the fifth message further includes a cause value for the modification, for example, because the UE is to be handed over to a non-MBS base station, MBS related information needs to be released.

[0247] S1003. The first access network device receives a fifth confirmation message corresponding to the fifth message sent by the core network device. The fifth confirmation message includes modification information of the first PDU session.

[0248] Before or at the same time as S1003 , the method further includes: the core network device modifies the first PDU session.

[0249] S1004: The first access network device deletes the information of the MBS session included in the first PDU session.

[0250] As a second possible implementation, the first access network device modifies the first PDU session and notifies the core network device. Therefore, this embodiment includes step S1005. Optionally, the core network device replies with a confirmation message, which also includes S1006.

[0251] S1005: The first access network device sends a modification message for the first PDU session. Correspondingly, the core network device receives the modification message for the first PDU session.

[0252] S1006: The core network device sends a modification confirmation message of the first PDU session. Correspondingly, the first access network device receives the modification confirmation message of the first PDU session.

[0253] S1007: The first access network device sends a handover indication message to the terminal device. The handover indication message is used to instruct the terminal device to switch to the target cell. In other words, the first access network device notifies the UE to switch to the cell served by the second access network device, which does not support MBS sessions. Accordingly, the terminal device receives the handover indication message.

[0254] If the current state of the MBS session is deactivated, and the PDU session associated with the MBS session includes the MBS QoS flow and QoS flows of other services, the creation of a new UP tunnel will introduce redundant messages, such as information about the QoS flows associated with the MBS session, wasting signaling resources and being useless. The method of this embodiment can avoid the waste of resources caused by deleting a newly created UP tunnel before it is used.

[0255] It should be noted that, in various embodiments of the present application, the first / second / third / fourth / fifth confirmation message may also be referred to as the first / second / third / fourth / fifth response message or the first / second / third / fourth / fifth feedback message, i.e., the response message or feedback message of the first / second / third / fourth / fifth message. In the embodiments of the present application, there is no restriction on the names of the first / second / third / fourth / fifth confirmation message. In addition, in the embodiments of the present invention, "release" may also be referred to as "deletion."

[0256] It should be noted that, in the various embodiments of the present application, the order of execution of the above-mentioned processes does not necessarily imply a specific order of execution. The order of execution of the processes should be determined by their functions and internal logic. The various numerical numbers or serial numbers involved in the above-mentioned processes are merely for the convenience of description and should not constitute any limitation on the implementation of the embodiments of the present application. For example, if the first message is a handover request message and the first confirmation message is a handover request confirmation message, S704 and S705 occur before the RAN handover is completed. If the first message is not a handover request message and the first confirmation message is not a handover request confirmation message, S704 and S705 may occur before, during, or after the RAN handover is completed.

[0257] Figure 11 A schematic diagram of the structure of a communication device provided in an embodiment of the present application is given. It should be noted that: Figure 11 The parts indicated by the dotted box are optional and will not be described in detail in the following text.

[0258] The communication device 1100 includes one or more processors 1101. The processor 1101 can be used to perform internal processing of the device and implement certain control processing functions. Optionally, the processor 1101 includes instructions 1103. Optionally, the processor 1101 can store data. The processor 1101 can be a general-purpose processor or a dedicated processor. For example, it includes at least one of the following: a baseband processor, a central processing unit, an application processor, a modem processor, a graphics processor, an image signal processor, a digital signal processor, a video codec processor, a controller, and / or a neural network processor. Different processors can be independent devices or integrated into one or more processors, for example, integrated into one or more dedicated integrated circuits.

[0259] Optionally, the communication device 1100 includes one or more memories 1102 for storing instructions 1104. Optionally, data may also be stored in the memories 1102. The processor and memory may be provided separately or integrated together.

[0260] Optionally, the communication device 1100 may further include a transceiver 1105. The transceiver 1105 may be used to send information to or receive information from other devices. The transceiver 1105 may be referred to as a transceiver, a transceiver circuit, an input / output interface, etc.

[0261] Optionally, the communication device 1100 may further include one or more of the following components: a wireless communication module, an audio module, an external memory interface, an internal memory, a universal serial bus (USB) interface, a power management module, an antenna, a speaker, a microphone, an input / output module, a sensor module, a motor, a camera, or a display screen, etc. These components may be implemented as hardware, software, or a combination of software and hardware.

[0262] The processor 1101 executes instructions (sometimes also referred to as computer programs or codes) stored in the communication device 1100. That is, the instructions stored in the communication device can be run on the processor 1101, so that the communication device 1100 performs the method described in the above embodiment. Optionally, the instruction is an instruction 1103 in the processor 1101, or the instruction is an instruction 1104 in the memory.

[0263] In one implementation, the communication device 1100 can be used to implement the method corresponding to the first access network device in the above-mentioned application embodiment. For specific functions, please refer to the description in the above-mentioned embodiment and will not be repeated here. Exemplarily, the communication device 1100 includes a processor 1101, and the processor 1101 is used to execute a computer program or instruction so that the method corresponding to the first access network device in the above-mentioned application embodiment is executed. Optionally, the processor 1101 can communicate with other network entities through the transceiver 1105, for example, communicating with the second access network device or the core network device. Optionally, the memory 1102 is used to store instructions and data of the first access network device.

[0264] In another implementation, the communication device 1100 can be used to implement the method corresponding to the second access network device in the above-mentioned application embodiment. For specific functions, please refer to the description in the above-mentioned embodiment and will not be repeated here. Exemplarily, the communication device 1100 includes a processor 1101, and the processor 1101 is used to execute a computer program or instruction so that the method corresponding to the second access network device in the above-mentioned application embodiment is executed. Optionally, the processor 1101 can communicate with other network entities through the transceiver 1105, for example, communicating with the first access network device or the core network device. Optionally, the memory 1102 is used to store instructions and data of the first access network device.

[0265] In another implementation, the communication device 1100 can be used to implement the method corresponding to the core network device in the above-mentioned application embodiment. For specific functions, please refer to the description in the above-mentioned embodiment and will not be repeated here. Exemplarily, the communication device 1100 includes a processor 1101, and the processor 1101 is used to execute a computer program or instruction so that the method corresponding to the core network device in the above-mentioned application embodiment is executed. Optionally, the processor 1101 can communicate with other network entities through the transceiver 1105, for example, communicate with the first access network device or the second access network device. Optionally, the memory 1102 is used to store instructions and data of the core network device.

[0266] The processor 1101 and transceiver 1105 described in this application can be implemented on an integrated circuit (IC), an analog IC, a radio frequency identification (RFID) integrated circuit, a mixed-signal IC, an application specific integrated circuit (ASIC), a printed circuit board (PCB), or an electronic device. The communication device described herein can be a standalone device (e.g., a standalone integrated circuit, a mobile phone, etc.), or can be part of a larger device (e.g., a module that can be embedded in other devices). For details, please refer to the aforementioned description of the core network device and the access network device, which will not be repeated here.

[0267] Figure 12 A schematic diagram of the structure of a communication device provided in an embodiment of the present application is given. Figure 12 As shown, apparatus 1200 may include a processing unit 1202 and a communication unit 1203. Processing unit 1202 is used to control and manage the operations of apparatus 1200. Communication unit 1203 is used to support communication between apparatus 1200 and other devices. Optionally, communication unit 1203 is also referred to as a transceiver unit and may include a receiving unit and / or a transmitting unit, each configured to perform receiving and transmitting operations. Apparatus 1200 may also include a storage unit 1201 for storing instructions and / or data for apparatus 1200.

[0268] In one implementation, the communication device 1200 can be used to implement the method corresponding to the first access network device or the second access network device in the above-mentioned application embodiment. For specific functions, please refer to the description in the above-mentioned embodiment and will not be repeated here. The processing unit 1202 can support the device 1200 to perform the actions of the first access network device or the second access network device in each method example above. Alternatively, the processing unit 1202 mainly performs the internal actions of the first access network device or the second access network device in the method example, and the communication unit 1203 can support the communication between the device 1200 and other devices. For example, support the device 1200 to communicate with the second access network device or the core network device, or support the device 1200 to communicate with the first access network device or the core network device.

[0269] In another implementation, the communication device 1200 can be used to implement the method corresponding to the core network device in the above-mentioned application embodiment. For specific functions, please refer to the description in the above-mentioned embodiment and will not be repeated here. The processing unit 1202 can support the device 1200 to perform the actions of the core network device in each method example above. Alternatively, the processing unit 1202 mainly performs the internal actions of the core network device in the method example, and the communication unit 1203 can support the communication between the device 1200 and other devices. For example, it supports the device 1200 to communicate with the first access network device or the second access network device.

[0270] Figure 13 This is a simplified schematic diagram of the structure of an access network device provided in an embodiment of the present application, for example, a simplified schematic diagram of the structure of a base station. This access network device 1300 can be applied to the first access network device or the second access network device in the above-described embodiment, and performs the operations or functions of the first access network device or the second access network device in the above-described method embodiment. For details, please refer to the description of the above-described method embodiment and will not be repeated here.

[0271] The access network device 1300 includes: a processor 1311, a memory 1312, a radio frequency unit 1321, and an antenna 1322. The processor 1311, also known as a processing unit, is configured to support the execution of the functions of the first access network device or the second access network device in the above-described method embodiments. The processor 1311 may be one or more processors. The one or more processors may support wireless access technologies of the same standard or different standards (e.g., LTE and NR). In one implementation, the processor 1311 is an integrated circuit, such as one or more ASICs, one or more DSPs, one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits may be integrated together to form a chip. The memory 1312, also known as a storage unit, is configured to store instructions (sometimes also referred to as computer programs or code) and / or data. The memory 1312 may be a single memory or a collective term for multiple memories or storage elements. The memory 1312 and the processor 1311 may be located on the same chip or on different chips. The radio frequency unit 1321 may be one or more radio frequency units. Antenna 1322 is mainly used for transmitting and receiving radio frequency signals in the form of electromagnetic waves, for example, for the access network device 1300 to send signals to or receive signals from a terminal device. In addition, the access network device 1300 also includes: a communication unit, wherein the communication unit is used to support communication between the access network device 1300 and other devices. For example, if the access network device 1300 is used to implement the method corresponding to the first access network device in the above-mentioned application embodiment, then the communication unit is used to support the access network device 1300 to communicate with the second access network device or the core network device. For example, if the access network device 1300 is used to implement the method corresponding to the second access network device in the above-mentioned application embodiment, then the communication unit is used to support the access network device 1300 to communicate with the first access network device or the core network device. Optionally, the communication unit may include a receiving unit and / or a sending unit, which are used to perform receiving and sending operations, respectively.

[0272] Optionally, the baseband unit 1310 (BBU) includes a processor 1311 and a memory 1312, which are mainly used for baseband processing of signals, managing wireless resources, providing transmission management and interfaces, providing clock signals and other functions. Optionally, the BBU 2100 can be composed of one or more single boards, and multiple single boards can jointly support a wireless access network with a single access standard (such as an LTE network), or can separately support wireless access networks with different access standards (such as an LTE network, a 5G network or other networks). The memory 1312 and processor 1311 can serve one or more single boards. In other words, a memory and a processor can be set separately on each single board. Alternatively, multiple single boards can share the same memory and processor. In addition, necessary circuits can also be set on each single board. BBU1310 can be used to execute the actions implemented by the first access network device or the second access network device described in the previous method embodiment.

[0273] Optionally, the radio frequency unit 1321 is a remote radio unit (RRU), and the RRU and the BBU may be physically arranged together or physically separated, that is, a distributed base station.

[0274] Optionally, unit 1320 may be an active antenna unit (AAU), a hardware product that integrates RF functionality with an antenna. The RF unit 1321 in the AAU is a dedicated RF module that functions similarly to an RRU. Optionally, the AAU may also include some baseband processing functionality.

[0275] Figure 14 This is a simplified structural diagram of a core network device provided in an embodiment of the present application, wherein the core network device may be a device with AMF function, or a device with AMF function and UPF function, or the core network device may be a device with AMF function and SMF function, or the core network device may be a device with AMF function, UPF function and SMF function.

[0276] The core network device 1400 may include a processor 1401, a memory 1402, and an interface circuit 1403. The processor 1401 may be configured to process communication protocols and communication data, and to control communication devices. The memory 1402 may be configured to store programs and data, and the processor 1401 may execute the methods performed by the core network device in the embodiments of the present application based on the programs. The interface circuit 1403 may be configured to enable the core network device 1400 to communicate with other devices. This communication may be wired or wireless. For example, the interface circuit may be a service-based communication interface.

[0277] The above memory 1402 may also be externally connected to the core network device 1400. In this case, the core network device 1400 may include an interface circuit 1403 and a processor 1401. The above interface circuit 1403 may also be externally connected to the core network device 1400. In this case, the core network device 1400 may include a memory 1402 and a processor 1401. When both the interface circuit 1403 and the memory 1402 are externally connected to the core network device 1400, the communication device 1400 may include a processor 1401.

[0278] Figure 14 The core network device shown can implement various processes related to the core network device in the above embodiments. Figure 14 The operations and / or functions of the modules in the core network device are respectively for implementing the corresponding processes in the above method embodiments. For details, please refer to the description in the above method embodiments, which will not be repeated here.

[0279] It is understood that in the embodiments of the present application, the terminal device and / or the network device may perform some or all of the steps in the embodiments of the present application. These steps or operations are merely examples, and the embodiments of the present application may also perform other operations or variations of various operations. In addition, the various steps may be performed in a different order than those presented in the embodiments of the present application, and it is possible that not all of the operations in the embodiments of the present application need to be performed.

[0280] The present application also provides a computer-readable storage medium, which stores a computer program or instruction. When the computer program or instruction is executed, the method performed by the first access network device, the second access network device or the core network device in the aforementioned method embodiment is implemented.

[0281] The present application also provides a computer program product comprising a computer program or instructions, which, when executed on a computer, enables the computer to execute the method executed by the first access network device, the second access network device or the core network device in any of the aforementioned method embodiments.

[0282] For the above-mentioned computer-readable storage medium or computer program product, when the computer program or instruction is executed, the computer executes the method executed by the first access network device in the above-mentioned embodiment; or, when the computer program or instruction is executed, the computer executes the method executed by the second access network device in the above-mentioned embodiment; or, when the computer program or instruction is executed, the computer executes the method executed by the core network device in the above-mentioned embodiment.

[0283] Exemplarily, the computer-readable storage medium or the computer program product includes: instructions for receiving a first message from a first access network device and sending a first confirmation message to the first access network device; instructions for sending a second message to a core network device and receiving a second confirmation message from the core network device; and / or instructions for sending a fourth message to the core network device and receiving a fourth confirmation message from the core network device. Exemplarily, the computer-readable storage medium or the computer program product includes: instructions for sending a first message to a second access network device and receiving a first confirmation message from the second access network device; instructions for receiving third information and saving the MBS status information in the MBS context and / or in the context of the terminal device; and / or instructions for determining that the status of the MBS session is deactivated and sending a fifth message to the core network device. Exemplarily, the computer-readable storage medium or the computer program product includes: instructions for receiving a second message from the second access network device and sending a second confirmation message to the second access network device; instructions for receiving a fourth message from the second access network device and sending a fourth confirmation message to the second access network device; instructions for determining the first state of the MBS session and sending third information to the first access network device; and / or instructions for receiving a fifth message from the first access network device.

[0284] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer 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 the present application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a tape, a magnetic disk), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0285] An embodiment of the present application also provides a processing device, including a processor and an interface; the processor is used to execute the method executed by the terminal device or network device involved in any of the above method embodiments.

[0286] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0287] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the division of the units is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. The mutual coupling, direct coupling, or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of devices or units, and can be electrical, mechanical or other forms.

[0288] Units described as separate components may or may not be physically separate, and 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 these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0289] It should be understood that references to "embodiments" throughout this specification mean that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment of the present application. Therefore, various embodiments throughout this specification do not necessarily refer to the same embodiment. Furthermore, these particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0290] It should also be understood that the names of all nodes and messages in this application are merely names set for the convenience of description in this application. The names in the actual network may be different. This application should not be understood to limit 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 a method or equivalent replacement of this application, and is within the scope of protection of this application. No further details will be given below.

[0291] It should be understood that the ordinal numbers "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects and are not used to limit the size, content, order, timing, priority, or importance of the multiple objects. For example, the configuration information of the first signal and the configuration information of the second signal can be the same configuration information or different configuration information, and such names do not indicate a difference in the amount of information, content, priority, or importance of the two configuration information.

[0292] It should also be understood that in this application, "when", "if" and "if" all mean that the network element will make corresponding processing under certain objective circumstances, which is not a time limit, and does not require the network element to make judgment actions when implementing it, nor does it mean that there are other limitations.

[0293] It should also be understood that, in this application, "at least one" means one or more, and "plurality" means two or more. "At least one item" or similar expressions refers to one or more items, that is, any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a, b, and c.

[0294] It should also be understood that expressions similar to "the item includes one or more of the following: A, B, and C" in this application generally mean, unless otherwise specified, that the item can be any one of the following: A; B; C; A and B; A and C; B and C; A, B and C; A and A; A, A and A; A, A and B; A, A and C, A, B and B; A, C and C; B and B, B, B and B, B, B and C, C and C; C, C and C, and other combinations of A, B and C. The above example uses A, B, and C as an example to illustrate the optional items of the item. When the expression is "the item includes at least one of the following: A, B, ..., and X", that is, when the expression contains more elements, the items to which the item can be applied can also be obtained according to the above rules.

[0295] It should also be understood that the term "and / or" in this document simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects are in an "or" relationship. For example, "A / B" means: A or B.

[0296] It should also be understood that in each embodiment of the present application, "A corresponds to B" 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 based solely on A, and B can also be determined based on A and / or other information.

[0297] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that: The method is applied to a second access network device or a chip in the second access network device, and the method includes: receiving a first message from a first access network device, where the first message indicates that a first state of a multicast broadcast service MBS session is activation or deactivation; Sending a first confirmation message corresponding to the first message to the first access network device; After receiving the first message sent by the first access network device, the method further includes: Sending a fourth message to a core network device, where the fourth message is used to request establishment of a user plane tunnel corresponding to the MBS session; A fourth confirmation message corresponding to the fourth message is received from the core network device, where the fourth confirmation message indicates that the second state of the MBS session is activation or deactivation.

2. The method according to claim 1, characterized in that The first message includes first state information, where the first state information indicates whether the first state is activated or deactivated; or The first message indicates whether the first state is activated or deactivated by whether it contains first state information.

3. The method according to claim 1 or 2, characterized in that The first message is a handover request message, and the first confirmation message is a handover request confirmation message.

4. The method according to claim 1 or 2, characterized in that The first state is the state of the MBS session before the terminal device is switched, and the second state is the state of the MBS session after the terminal device is switched. The MBS is the MBS that the terminal device is interested in or is receiving.

5. The method according to claim 1 or 2, characterized in that After receiving the first message sent by the first access network device, the method further includes: Sending a second message to the core network device; receiving, from the core network device, a second confirmation message corresponding to the second message; The second message indicates the first state, the second confirmation message indicates that the second state of the MBS session is activation or deactivation, the second message is a path switch request message, and the second confirmation message is a path switch request confirmation message.

6. The method according to claim 4, characterized in that The second state is activation or deactivation. After receiving the first message sent by the first access network device, the method further includes: Determine that the state of the MBS session is the second state.

7. The method according to claim 4, characterized in that The first state is activation, the second state is deactivation, and the method further includes: It is determined that the state of the MBS session is deactivated.

8. The method according to any one of claims 1-2, 6-7, characterized in that: The method is applied to a first access network device or a chip in the first access network device, and the method includes: Sending a first message to the second access network device, where the first message indicates that a first state of the multicast broadcast service MBS session is activation or deactivation; A first confirmation message corresponding to the first message is received from the second access network device.

9. The method according to claim 8, characterized in that The first message includes first state information, where the first state information indicates whether the first state is activated or deactivated; or The first message indicates whether the first state is activated or deactivated by whether it contains first state information.

10. The method according to claim 8, characterized in that The first message is a handover request message, and the first confirmation message is a handover request confirmation message.

11. The method according to claim 8, characterized in that Before sending the first message to the second access network device, the method further includes: receiving third information from a core network device, where the third information indicates a first state of the MBS session; The third information is information included in the MBS session change message; or, The third information is information included in a PDU session change message, or the third information is information included in a PDU session establishment message, wherein the PDU session is associated with the MBS session; or The third information is information in an information field in the header of the data packet of the MBS service.

12. A communication method, characterized in that: The method is applied to a second access network device or a chip in the second access network device, and the method includes: Sending a fourth message to the core network device, where the fourth message is used to request establishment of a user plane tunnel corresponding to the MBS session; A fourth confirmation message corresponding to the fourth message is received from the core network device, where the fourth confirmation message indicates that the second state of the MBS session is activation or deactivation.

13. The method according to claim 12, characterized in that Before sending the fourth message to the core network device, the method further includes: receiving a first message from a first access network device, where the first message indicates that a first state of the MBS session is activation or deactivation; Send a first confirmation message corresponding to the first message to the first access network device.

14. The method according to claim 13, characterized in that The first message includes first state information, where the first state information indicates whether the first state is activated or deactivated; or The first message indicates whether the first state is activated or deactivated by whether it contains first state information.

15. The method according to claim 13 or 14, characterized in that The first message is a handover request message, and the first confirmation message is a handover request confirmation message.

16. The method according to claim 13 or 14, characterized in that The first state is the state of the MBS session before the terminal device is switched, the second state is the state of the MBS session after the terminal device is switched, and the MBS is the MBS that the terminal device is interested in or is receiving.

17. The method according to any one of claims 12 to 14, characterized in that The fourth confirmation message indicates that the second state of the MBS session is activation or deactivation. After receiving the fourth confirmation message corresponding to the fourth message from the core network device, the method further includes: Determine that the state of the MBS session is the second state.

18. The method according to claim 13 or 14, characterized in that The first state is activated, the second state is deactivated, and after receiving a fourth confirmation message of the fourth message sent by the core network device, the method further includes: It is determined that the state of the MBS session is deactivated.

19. The method according to claim 12, wherein: The fourth confirmation message includes information for establishing the user plane tunnel and indicates that the state of the MBS session is active; or, The fourth confirmation message includes information of rejecting the establishment of the user plane tunnel; or, The fourth confirmation message includes information for establishing the user plane tunnel and indicates that the state of the MBS session is deactivated.

20. A communication method, characterized in that: The method is applied to a core network device or a chip in the core network device, and the method includes: receiving a fourth message from the second access network device, where the fourth message is used to request establishment of a user plane tunnel corresponding to the MBS session; A fourth confirmation message corresponding to the fourth message is sent to the second access network device, where the fourth confirmation message indicates that the second state of the MBS session is activation or deactivation.

21. The method according to claim 20, characterized in that The second state is the state of the MBS session after the terminal device is switched, the first state is the state of the MBS session before the terminal device is switched, and the MBS is the MBS that the terminal device is interested in or is receiving.

22. The method according to claim 21, characterized in that The first state is activated, the second state is deactivated, and the second access network device determines that the state of the MBS session is deactivated.

23. The method according to claim 20, characterized in that The fourth confirmation message includes information for establishing the user plane tunnel and indicates that the second state of the MBS session is active; or, The fourth confirmation message includes information of rejecting the establishment of the user plane tunnel; or, The fourth confirmation message includes information for establishing the user plane tunnel and indicates that the second state of the MBS session is deactivated.

24. A communication device, characterized in that: include: a sending unit, configured to send a fourth message, where the fourth message is used to request establishment of a user plane tunnel corresponding to the MBS session; A receiving unit is configured to receive a fourth confirmation message corresponding to the fourth message, where the fourth confirmation message indicates that the second state of the MBS session is activation or deactivation.

25. The device according to claim 24, characterized in that The receiving unit is further configured to receive a first message, where the first message indicates that the first state of the MBS session is activation or deactivation; The sending unit is further configured to send a first confirmation message corresponding to the first message.

26. The device according to claim 25, characterized in that The first message includes first state information, where the first state information indicates whether the first state is activated or deactivated; or The first message indicates whether the first state is activated or deactivated by whether it contains first state information.

27. The device according to claim 25 or 26, characterized in that The first message is a handover request message, and the first confirmation message is a handover request confirmation message.

28. The device according to claim 25 or 26, characterized in that The first state is the state of the MBS session before the terminal device is switched, the second state is the state of the MBS session after the terminal device is switched, and the MBS is the MBS that the terminal device is interested in or is receiving.

29. The device according to any one of claims 24 to 26, characterized in that The fourth confirmation message indicates that the second state of the MBS session is activation or deactivation, and the apparatus further includes: The processing unit is configured to determine that the state of the MBS session is the second state.

30. The device according to claim 25 or 26, characterized in that The first state is activation, the second state is deactivation, and the apparatus further includes: The processing unit is further configured to determine that the state of the MBS session is deactivated.

31. A communication device, characterized in that: include: a receiving unit, configured to receive a fourth message, where the fourth message is used to request establishment of a user plane tunnel corresponding to the MBS session; A sending unit is configured to send a fourth confirmation message corresponding to the fourth message, where the fourth confirmation message indicates that the second state of the MBS session is activation or deactivation.

32. The device according to claim 31, characterized in that The second state is the state of the MBS session after the terminal device is switched, the first state is the state of the MBS session before the terminal device is switched, and the MBS is the MBS that the terminal device is interested in or is receiving.

33. The device according to claim 32, characterized in that The first state is activated, and the second state is deactivated.

34. A communication device, characterized in that: The communication device includes a processor and a memory, the memory is used to store computer programs or instructions, and the processor is used to execute the computer program or instructions in the memory, so that the method of any one of claims 1 to 7 is executed, or the method of any one of claims 12 to 19 is executed.

35. A communication device, characterized in that: The communication device includes a processor and a memory, wherein the memory is used to store computer programs or instructions, and the processor is used to execute the computer programs or instructions in the memory, so that the method according to any one of claims 8 to 11 is executed.

36. A communication device, characterized in that The communication device includes a processor and a memory, wherein the memory is used to store computer programs or instructions, and the processor is used to execute the computer programs or instructions in the memory, so that the method according to any one of claims 20 to 23 is performed.

37. A computer-readable storage medium, characterized in that A computer program or instructions is stored, wherein the computer program or instructions are used to implement the method of any one of claims 1 to 7, or to implement the method of any one of claims 8 to 11, or to implement the method of any one of claims 12 to 19, or to implement the method of any one of claims 20 to 23.

38. A communication system, characterized in that: Comprising the communication device as claimed in claim 34, the communication device as claimed in claim 35 and the communication device as claimed in claim 36; or, comprising the communication device as claimed in claim 34 and the communication device as claimed in claim 35; or, comprising the communication device as claimed in claim 34 and the communication device as claimed in claim 36.

39. A computer program product, characterized in that The method comprises a computer program or instructions which, when executed, causes a computer to perform the method according to any one of claims 1 to 7, or the method according to any one of claims 8 to 11, or the method according to any one of claims 12 to 19, or the method according to any one of claims 20 to 23.

Images