Multicast / broadcast service communication method, device, and system

Abstract

The embodiments of the present application disclose a multicast / broadcast service communication method, apparatus and system to solve the problem that access network devices across areas cannot implement SFN in a multicast / broadcast communication scenario. The method includes: a first network element determines a quality of service flow identifier QFI of a multicast / broadcast service; and the first network element sends the QFI to at least two session management function network elements. The solution of the present application can be applied in the field of communication technologies, such as artificial intelligence, Internet of Vehicles, or Internet of Smart Homes.

Description

[Technical Field]

[0001] TECHNICAL FIELD Embodiments of the present application relate to the field of communication technologies, and in particular to a multicast / broadcast service communication method, apparatus, and system. [Background technology]

[0003] With the development of mobile Internet, mobile high-definition video services are experiencing a surge. The mode of watching video services (such as the latest programs) by users is gradually changing from the traditional mode of watching video services by using fixed televisions to the mode of watching video services by using terminals and mobile networks. A large number of users are watching video services by using terminals and mobile networks. As a result, video services are having an increasingly strong impact on mobile networks.

[0004] To solve this problem, multicast / broadcast mode is introduced. Video services are transmitted to a large number of users in multicast / broadcast mode, which greatly reduces the impact of video services on mobile networks. In the process of transmitting video services in multicast / broadcast mode, there are some problems that need to be solved and discussed urgently, such as the problem of video services received by users across areas being asynchronous with each other, or the problem of video services being interrupted during cell handover. Summary of the Invention

[0005] The embodiments of the present application provide a multicast / broadcast service communication method, apparatus, and system for solving some problems that arise when services are transmitted in a multicast / broadcast manner, such as the problem of video services received by users across areas being asynchronous, or the problem of video services being interrupted during cell handover.

[0006] For example, the problem of video services received by users across areas being asynchronous when the services are transmitted in a multicast / broadcast manner is solved. To achieve this objective, the technical solutions in the first and second aspects are used in the embodiments of the present application. For example, the problem of video services being interrupted during cell handover is solved. To achieve this objective, the technical solutions in the tenth to twelfth aspects are used in the embodiments of the present application. Each technical solution will be described below.

[0007] According to a first aspect, an embodiment of the present application provides a multicast / broadcast service communication method, which may include: a first network element determining a Quality of Service flow identifier (QFI) for a multicast / broadcast service; and the first network element sending the QFI to at least two session management function network elements.

[0008] According to the method of the first aspect, a first network element centrally determines a QFI of a multicast / broadcast service and distributes the QFI evenly to multiple session management function network elements in different areas, so that different session management function network elements across the areas obtain the same QFI, determine the same QoS profile based on the same QFI, and send the QoS profile to access network devices in the service range / service area of the session management function network element. In this manner, the access network devices in different areas obtain the same QoS profile and establish the same radio bearer resource for transmitting data of the multicast / broadcast service based on the same QoS profile, thereby implementing SFN between the access network devices across the areas. In other words, data of the same multicast / broadcast service is simultaneously transmitted to terminals at the same frequency to ensure that terminal users in different areas receive the data of the multicast / broadcast service, thereby implementing successful transmission of the data of the multicast / broadcast service.

[0009] In a possible design, the session management function network element is a multicast / broadcast session management function MB-SMF or a session management function SMF. Based on this possible design, the session management function network element can be flexibly and effectively designed to extend the application scenario of this solution.

[0010] In a possible design, the first network element is one of a network publication function NEF, a multicast / broadcast service function MBSF, a network element obtained after both the NEF and the MBSF are deployed, or a network element called an unstructured data storage function UDSF. Based on this possible design, the first network element can be flexibly and effectively designed to extend the application scenario of this solution.

[0011] In one possible design, the first network element determining the QFI for the multicast / broadcast service includes the first network element obtaining information about the multicast / broadcast service from an application server and determining the QFI for the multicast / broadcast service based on the information about the multicast / broadcast service. Alternatively, the first network element determines the QFI for the multicast / broadcast service based on a policy / charging control PCC rule for the multicast / broadcast service.

[0012] Based on this possible design, the QFI of a multicast / broadcast service can be determined flexibly and effectively in multiple ways.

[0013] In a possible design, the information about the multicast / broadcast service includes identifier information of the multicast / broadcast service and / or requirement information of the multicast / broadcast service. Based on this possible design, the information about the multicast / broadcast service is designed flexibly and effectively.

[0014] In a possible design, the first network element transmitting the QFI to the at least two session management function network elements includes the first network element transmitting the QFI to the at least two session management function network elements by using a PCF.

[0015] Based on this possible design, the first network element can send the QFI to multiple session management function network elements by using the PCF, which makes the existing message transmission procedures compatible / reused and simplifies the system design.

[0016] According to a second aspect, an embodiment of the present application provides a multicast / broadcast service communication method, the method including: a first session management function network element receiving a QFI of a multicast / broadcast service from the first network element; and the first session management function network element sending a QFI and a quality of service profile (QoS profile) to a first access network device based on the QFI.

[0017] In one possible design, the method further includes the second session management function network element receiving a QFI for the multicast / broadcast service from the first network element, and the second session management function network element sending a QFI and a QoS profile to the second access network device based on the QFI, where the QoS profile sent by the second session management function network element to the second access network device is the same as the QoS profile sent by the first session management function network element to the first access network device.

[0018] According to the method of the second aspect, different session management function network elements across areas obtain the same QFI, determine the same QoS profile based on the same QFI, and separately transmit the QoS profile to access network devices in a local area. In this manner, the access network devices in different areas obtain the same QoS profile and establish the same radio bearer resource for transmitting data of a multicast / broadcast service based on the same QoS profile, thereby implementing SFN between the access network devices across the areas. In other words, data of the same multicast / broadcast service is simultaneously transmitted to terminals at the same frequency to ensure that terminal users in different areas receive the data of the multicast / broadcast service, thereby implementing successful transmission of data of the multicast / broadcast service.

[0019] In a possible design, the second access network device is connected to a user plane function (UPF) managed by a second session management function network element, and the first access network device is connected to a UPF managed by the first session management function network element.

[0020] Based on this possible design, different access network devices are placed on different user planes, whereby the different access network devices simultaneously transmit data of the same multicast / broadcast service to terminals on the same frequency based on the same QoS profile, thereby implementing SFN.

[0021] According to a third aspect, the present application provides a communication device. The communication device may be a first network element, or a chip or system-on-chip in the first network element, or may be a functional module within the communication device configured to implement the method in the first aspect or any one of possible designs of the first aspect. The communication device may implement functions performed by the communication device in the aforementioned aspects or possible designs, and the functions may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions. For example, the communication device may include a processing unit and a transmitting unit.

[0022] The processing unit is configured to determine a QFI for the multicast / broadcast service.

[0023] The sending unit is configured to send the QFI to at least two session management function network elements.

[0024] For specific implementation of this communication device, please refer to the behavioral function of the first network element in the multicast / broadcast service communication method provided in the first aspect or any one of the possible designs of the first aspect. Details will not be described again in this specification. Therefore, the first network element provided in the third aspect achieves the same beneficial effects as the first aspect or any one of the possible designs of the first aspect.

[0025] According to a fourth aspect, the present application provides a communications device. The communications device may be a first session management function network element, or a chip or system-on-chip in the first session management function network element, or may be a functional module within the communications device configured to implement the method of the second aspect or any one of possible designs of the second aspect. The communications device may implement the functions performed by the communications device in the aforementioned aspects or possible designs, and the functions may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions. For example, the communications device may include a processing unit and a transceiver unit.

[0026] The processing unit is configured to control the transceiver unit to receive a QFI of the multicast / broadcast service from the first network element.

[0027] The processing unit is further configured to send the QFI and a QoS profile to the first access network device based on the QFI.

[0028] For specific implementation of this communication device, please refer to the behavioral function of the first session management function network element in the multicast / broadcast service communication method provided in the second aspect or any one of the possible designs of the second aspect. Details will not be described again in this specification. Therefore, the first session management function network element provided in the fourth aspect achieves the same beneficial effects as those of the second aspect or any one of the possible designs of the second aspect.

[0029] According to a fifth aspect, a communications device is provided. The communications device may be a first network element, or a chip or system-on-chip in the first network element. The communications device may implement functions performed by the first network element in the aforementioned aspects or possible designs, and these functions may be implemented by hardware. Alternatively, the communications device may be a first session management function network element, or a chip or system-on-chip in the first session management function network element. The communications device may implement functions performed by the first session management function network element in the aforementioned aspects or possible designs, and these functions may be implemented by hardware. In a possible design, the communications device may include a processor and a communications interface. The processor may be configured to support the communications device in implementing the functions of the first network element in the first aspect or any one of the possible designs of the first aspect, or the functions of the first session management function network element in the second aspect or any one of the possible designs of the second aspect.

[0030] In another possible design, the communications device may further include a memory configured to store computer-executable instructions and data necessary for the communications device, and when the communications device is running, the processor executes the computer-executable instructions stored in the memory to enable the communications device to perform the multicast / broadcast service communication method of the first aspect or any one of the possible designs of the first aspect, or the multicast / broadcast service communication method of the second aspect or any one of the possible designs of the second aspect.

[0031] According to a sixth aspect, there is provided a computer-readable storage medium. The computer-readable storage medium may be a readable non-volatile storage medium. The computer-readable storage medium stores instructions that, when run on a computer, enable the computer to perform the multicast / broadcast service communication method of the first aspect or any one of possible designs of the first aspect, or the multicast / broadcast service communication method of the second aspect or any one of possible designs of the second aspect.

[0032] According to a seventh aspect, there is provided a computer program product comprising instructions, which when run on a computer, enables the computer to perform the multicast / broadcast service communication method of the first aspect or any one of its possible designs, or the multicast / broadcast service communication method of the second aspect or any one of its possible designs.

[0033] According to an eighth aspect, there is provided a communications device. The communications device may be a first network element, a chip or system-on-chip in the first network element, or a first session management function, a chip or system-on-chip in the first session management function. The communications device includes one or more processors and one or more memories. The one or more memories are coupled to the one or more processors, and the one or more memories are configured to store computer program code. The computer program code includes computer instructions, and when the one or more processors execute the computer instructions, the communications device is enabled to perform the multicast / broadcast service communication method of the first aspect or any one of possible designs of the first aspect.

[0034] According to a ninth aspect, an embodiment of the present application provides a communication system, which may include the communication device according to the third aspect and the communication device according to the fourth aspect.

[0035] According to a tenth aspect, an embodiment of the present application provides a multicast / broadcast service communication method. The method includes: a source access network device obtaining first configuration information. The first configuration information is used by the terminal to receive data belonging to the multicast / broadcast service transmitted over a multicast / broadcast session after the terminal is handed over to a target access network device. The source access network device transmits the first configuration information to the terminal.

[0036] Based on the method in the tenth aspect, the source access network device obtains related configuration information of a multicast / broadcast session that is pre-configured by the target access network device for a terminal and is for transmitting data of the multicast / broadcast service, and sends the configuration information to the terminal, so that the terminal transmits the data of the multicast / broadcast service by using resources of the pre-configured multicast / broadcast session as soon as possible after the terminal is handed over to the target access network device, thereby reducing the interruption delay of the multicast / broadcast service and improving the transmission efficiency of the multicast / broadcast service.

[0037] In a possible design, the transmission mode of the target access network device is an SC-PTM mode. The first configuration information is SCPTMConfiguration information, which includes SC-MTCH information, which includes mbmsSessionInfo and g-RNTI. In other words, this technical solution is applicable to SC-PTM scenarios, and reduces service interruption delay during cell handover in SC-PTM scenarios.

[0038] In a possible design, the transmission mode of the target access network device is an MBSFN mode. The first configuration information is MBSFNAreaConfiguration information, which includes PMCH information, which includes pmch-Config and mbms-SessionInfoList, which includes information about multicast / broadcast sessions. In other words, this technical solution is applicable to MBSFN scenarios, and reduces service interruption delay during cell handover in MBSFN scenarios.

[0039] In a possible design, the source access network device obtaining the first configuration information includes the source access network device receiving the first configuration information, where the first configuration information is carried in a handover request response or a handover command. In other words, the first configuration information is carried to the source access network device by using an existing cell handover procedure to reduce signaling overhead.

[0040] In one possible design, the receiving of the first configuration information by the source access network device includes the source access network device receiving the first configuration information from a mobility management network element, in other words, the first configuration information is received by using a core network element, which is compatible with existing signaling transmission procedures, reduces signaling overhead, and simplifies system design.

[0041] In a possible design, the method further includes the source access network device sending information about the multicast / broadcast service to the target access network device. Alternatively, the source access network device sends information about the multicast / broadcast service to a mobility management network element.

[0042] In a possible design, the source access network device receiving the first configuration information includes the source access network device receiving the first configuration information from the target access network device, in other words, the source access network device directly exchanging the first configuration information with the target access network device to reduce message transmission latency.

[0043] In a possible design, the method further includes the source access network device sending information about the multicast / broadcast service to the target access network device.

[0044] In a possible design, the information about the multicast / broadcast service includes identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service. The information about the multicast / broadcast service is designed effectively and flexibly to expand application scenarios of this method.

[0045] In a possible design, the method further includes the source access network device determining the target access network device based on measurement reports of the terminals and / or multicast / broadcast capability information of the access network devices.

[0046] In a possible design, the measurement report includes identifier information of the multicast / broadcast service. The method further includes the source access network device sending the identifier information of the multicast / broadcast service to the mobility management network element or the target access network device. In other words, the identifier information of the multicast / broadcast service is carried in the measurement report and sent to the target access network device or core network device, so that the target access network device or core network device knows that the terminal is participating in the multicast / broadcast service. This simplifies system design and reduces signaling overhead.

[0047] According to an eleventh aspect, an embodiment of the present application provides a multicast / broadcast service communication method. The method includes a target access network device allocating resources of a multicast / broadcast session to a terminal. The multicast / broadcast session is for transmitting data of the multicast / broadcast service. The target access network device transmits first configuration information. The first configuration information represents resources of the multicast / broadcast session, and the first configuration information is used by the terminal to receive data of the multicast / broadcast service transmitted on the multicast / broadcast session after the terminal is handed over to the target access network device.

[0048] Based on the method in the eleventh aspect, the target access network device pre-configures, with respect to a terminal, resources of a multicast / broadcast session for transmitting data of the multicast / broadcast service, and sends configuration information to the terminal, so that the terminal transmits data of the multicast / broadcast service by using the pre-configured resources of the multicast / broadcast session as soon as possible after the terminal is handed over to the target access network device, thereby reducing the interruption delay of the multicast / broadcast service and improving the transmission efficiency of the multicast / broadcast service.

[0049] The transmission mode of the target access network device is SC-PTM mode or MBSFN mode. For related descriptions of the first setting information, please refer to the descriptions in the possible design of the tenth aspect. Details will not be described again.

[0050] In a possible design, the target access network device sending the first configuration information includes the target access network device sending the first configuration information to a mobility management network element. Alternatively, the target access network device sends the first configuration information to the source access network device. Thus, the first configuration information is sent flexibly and effectively, and the application scenario of the method is expanded.

[0051] In a possible design, the first configuration information is carried in a handover request response or a handover command, that is, the first configuration information is transmitted by using an existing handover procedure to reduce signaling overhead.

[0052] In a possible design, the method further includes the target access network device receiving information related to the multicast / broadcast service. The target access network device allocating resources of the multicast / broadcast session to the terminal includes the target access network device allocating resources of the multicast / broadcast session to the terminal based on the information related to the multicast / broadcast service, ensuring that the determined resources of the multicast / broadcast session are applicable for transmitting data of the multicast / broadcast service.

[0053] In a possible design, the information about the multicast / broadcast service includes identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service. The information about the multicast / broadcast service is designed effectively and flexibly to expand application scenarios of this method.

[0054] According to a twelfth aspect, an embodiment of the present application provides a multicast / broadcast service communication method. The method includes a terminal receiving first configuration information from a source access network device. The first configuration information represents resources of a multicast / broadcast session, and the first configuration information is used by the terminal to receive data belonging to the multicast / broadcast service transmitted on the multicast / broadcast session after the terminal is handed over to a target access network device. The terminal receives the data belonging to the multicast / broadcast service from the target access network device by using the multicast / broadcast session and based on the first configuration information.

[0055] Based on the method in the twelfth aspect, the target access network device pre-configures, with respect to a terminal, resources of a multicast / broadcast session for transmitting data of the multicast / broadcast service, and sends configuration information to the terminal, so that the terminal transmits data of the multicast / broadcast service by using the pre-configured resources of the multicast / broadcast session as soon as possible after the terminal is handed over to the target access network device, thereby reducing the interruption delay of the multicast / broadcast service and improving the transmission efficiency of the multicast / broadcast service.

[0056] In a possible design, the transmission mode of the target access network device is an SC-PTM mode or an MBSFN mode. For a related description of the first setting information, please refer to the description in the possible design of the tenth aspect. Details will not be described again.

[0057] In one possible design, the method further includes the terminal transmitting a measurement report including identifier information of the multicast / broadcast service to the source access network device. In other words, the identifier information of the multicast / broadcast service is added to the measurement report and transmitted to the source access network device, so that the source access network device knows that the terminal is participating in the multicast / broadcast service. This simplifies system design and reduces signaling overhead.

[0058] In a possible design, the first configuration information is carried in a handover request response or a handover command, that is, the first configuration information is transmitted by using an existing handover procedure to reduce signaling overhead.

[0059] According to a thirteenth aspect, the present application provides a communications device. The communications device may be a source access network device, or a chip or system-on-chip in the source access network device, or may be a functional module within the communications device configured to implement the method of the tenth aspect or any one of the possible designs of the tenth aspect. The communications device may implement the functions performed by the communications device in the aforementioned aspects or possible designs, and the functions may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions. For example, the communications device may include a processing unit and a transceiver unit.

[0060] The processing unit is configured to control the transceiver unit to obtain first configuration information, which is used by the terminal to receive data belonging to a multicast / broadcast service transmitted on a multicast / broadcast session after the terminal is handed over to the target access network device.

[0061] The transceiver unit is configured to transmit the first configuration information to the terminal.

[0062] For specific implementation of this communication device, please refer to the behavioral functions of the source access network device in the multicast / broadcast service communication method provided in the tenth aspect or any one of the possible designs of the tenth aspect. Details will not be described again in this specification. Therefore, the source access network device provided in the thirteenth aspect achieves the same beneficial effects as the tenth aspect or any one of the possible designs of the tenth aspect.

[0063] According to a fourteenth aspect, the present application provides a communications device. The communications device may be a target access network device, or a chip or system-on-chip in the target access network device, or may be a functional module within the communications device configured to implement the method of the eleventh aspect or any one of the possible designs of the eleventh aspect. The communications device may implement the functions performed by the communications device in the aforementioned aspects or possible designs, and the functions may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions. For example, the communications device may include a processing unit and a transmitting unit.

[0064] The processing unit is configured to allocate resources of a multicast / broadcast session to the terminal, the multicast / broadcast session being for transmitting data of the multicast / broadcast service.

[0065] The transmitting unit is configured to transmit first configuration information, the first configuration information representing resources of a multicast / broadcast session, the first configuration information being used by the terminal to receive data belonging to a multicast / broadcast service transmitted on the multicast / broadcast session after the terminal is handed over to the target access network device.

[0066] For specific implementation of this communication device, please refer to the behavioral function of the target access network device in the multicast / broadcast service communication method provided in the eleventh aspect or any one of the possible designs of the eleventh aspect. Details will not be described again in this specification. Therefore, the target access network device provided in the fourteenth aspect achieves the same beneficial effects as the eleventh aspect or any one of the possible designs of the eleventh aspect.

[0067] According to a fifteenth aspect, the present application provides a communication device. The communication device may be a terminal, a chip or a system-on-chip in the terminal, or a functional module within the communication device configured to implement the method of the twelfth aspect or any one of the possible designs of the twelfth aspect. The communication device may implement the functions performed by the communication device in the aforementioned aspects or possible designs, and the functions may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions. For example, the communication device may include a receiving unit and a processing unit.

[0068] The receiving unit is configured to receive first configuration information from a source access network device, the first configuration information representing resources of a multicast / broadcast session, and the first configuration information being used by the terminal to receive data belonging to a multicast / broadcast service transmitted on the multicast / broadcast session after the terminal is handed over to the target access network device.

[0069] The processing unit is configured to receive data belonging to the multicast / broadcast service coming from the target access network device by using the multicast / broadcast session and based on the first configuration information.

[0070] For specific implementation of this communication device, please refer to the behavioral function of the terminal in the multicast / broadcast service communication method provided in the twelfth aspect or any one of the possible designs of the twelfth aspect. Details will not be described again in this specification. Therefore, the terminal provided in the fifteenth aspect achieves the same beneficial effects as the terminal provided in the twelfth aspect or any one of the possible designs of the twelfth aspect.

[0071] According to a sixteenth aspect, there is provided a communications apparatus. The communications apparatus may be a source access network device, or a chip or system-on-chip in the source access network device. Alternatively, the communications apparatus may be a target access network device, or a chip or system-on-chip in the target access network device. Alternatively, the communications apparatus may be a terminal, or a chip or system-on-chip in the terminal. Functions may be implemented by hardware. In a possible design, the communications apparatus may include a processor and a communications interface. The processor may be configured to support the communications apparatus in implementing functions of the source access network device in the tenth aspect or any one of the possible designs of the tenth aspect, functions of the target access network device in the eleventh aspect or any one of the possible designs of the eleventh aspect, or functions of the terminal in the twelfth aspect or any one of the possible designs of the twelfth aspect.

[0072] In another possible design, the communications device may further include a memory configured to store computer-executable instructions and data necessary for the communications device. When the communications device is running, the processor executes the computer-executable instructions stored in the memory to enable the communications device to perform the multicast / broadcast service communication method of the tenth aspect or any one of its possible designs, the multicast / broadcast service communication method of the eleventh aspect or any one of its possible designs, or the multicast / broadcast service communication method of the twelfth aspect or any one of its possible designs.

[0073] According to a seventeenth aspect, there is provided a computer-readable storage medium, which may be a readable non-volatile storage medium, storing instructions that, when run on a computer, enable the computer to perform the multicast / broadcast service communication method of the tenth aspect or any one of its possible designs, the multicast / broadcast service communication method of the eleventh aspect or any one of its possible designs, or the multicast / broadcast service communication method of the twelfth aspect or any one of its possible designs.

[0074] According to an eighteenth aspect, there is provided a computer program product comprising instructions which, when run on a computer, enable the computer to perform the multicast / broadcast service communication method of the tenth aspect or any one of its possible designs, the multicast / broadcast service communication method of the eleventh aspect or any one of its possible designs, or the multicast / broadcast service communication method of the twelfth aspect or any one of its possible designs.

[0075] According to a 19th aspect, there is provided a communications device. The communications device may be a first network element, a chip or system-on-chip in the first network element, or a first session management function, or a system-on-chip in the first session management function. The communications device includes one or more processors and one or more memories. The one or more memories are coupled to the one or more processors, and the one or more memories are configured to store computer program code, the computer program code including computer instructions. When the one or more processors execute the computer instructions, the communications device is enabled to perform the multicast / broadcast service communication method of the 10th aspect or any one of possible designs of the 10th aspect, the multicast / broadcast service communication method of the 11th aspect or any one of possible designs of the 11th aspect, or the multicast / broadcast service communication method of the 12th aspect or any one of possible designs of the 12th aspect.

[0076] According to a twentieth aspect, an embodiment of the present application provides a communication system, which may include the communication device according to the thirteenth aspect, the communication device according to the fourteenth aspect, and the communication device according to the fifteenth aspect. [Brief explanation of the drawings]

[0077] [Figure 1] 1 is a schematic diagram of a multi-area multicast / broadcast communication scenario according to an embodiment of the present application; [Figure 2] 1 is a diagram of an architecture of a communication system according to an embodiment of the present application; [Figure 3] 1 is a schematic diagram of the architecture of a 5G communication system according to an embodiment of the present application; [Figure 4] 4 is a schematic diagram of a configuration of a communication device 400 according to an embodiment of the present application. [Figure 5]1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 6] 4 is a flowchart of another multicast / broadcast service communication method according to an embodiment of the present application; [Figure 7] 1 is a schematic diagram of a configuration of a communication device 70 according to an embodiment of the present application. [Figure 8] 1 is a schematic diagram of a configuration of a communication device 80 according to an embodiment of the present application. [Figure 9] 1 is a schematic diagram of the configuration of a communication system according to an embodiment of the present application; [Figure 10] 1 is a diagram of an architecture of a communication system according to an embodiment of the present application; [Figure 11a] 1 is a schematic diagram of the architecture of a 5G communication system according to an embodiment of the present application; [Figure 11b] 1 is a schematic diagram of an architecture in which a 4G network interacts with a 5G network according to an embodiment of the present application; [Figure 12] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 13] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 14] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 15A] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 15B] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 16] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 17A] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 17B] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 18A] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 18B] 1 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application; [Figure 19] 1 is a schematic diagram of a configuration of a communication device 190 according to an embodiment of the present application. [Figure 20] 1 is a schematic diagram of a configuration of a communication device 200 according to an embodiment of the present application. [Figure 21] 2 is a schematic diagram of a configuration of a communication device 210 according to an embodiment of the present application. [Figure 22] 1 is a schematic diagram of the configuration of a communication system according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0078] In a multi-area multicast / broadcast communication scenario, in order to ensure normal transmission of data of multicast / broadcast services, access network devices across areas may establish the same user plane transmission channel for transmitting data of multicast / broadcast services, whereby the access network devices across areas are in a single frequency network (SFN) and transmit data of the same multicast / broadcast service at the same frequency simultaneously.

[0079] The fourth generation (4 thA 4G (4th generation) multicast / broadcast network architecture is used as an example. In the 4G multicast / broadcast network architecture, a multicast / broadcast service center (BM-SC) serves as a centralized control node to perform quality of service (QoS) control on multicast / broadcast services. In addition, a synchronization (SYNC) protocol is further used between the BM-SC and access network devices (e.g., enhanced NodeBs (eNBs)) to ensure synchronous transmission of user plane data. For example, the BM-SC distributes QoS information in a unified manner and distributes the QoS information to multiple multimedia broadcast multicast / broadcast service gateways (MBMS-GWs) to ensure consistency of the QoS information distributed to the multiple MBMS-GWs. Therefore, the MBMS-GWs establish the same user plane transmission channel based on the QoS information, thereby enabling access network devices across areas to be deployed in an SFN. Specifically, access network devices across different areas simultaneously transmit data of the same multicast / broadcast service at the same frequency.

[0080] Unlike in the 4G multicast / broadcast network architecture, in the 5G multicast / broadcast network architecture, user plane network elements are separated from control plane network elements, and the user plane network elements and the control plane network elements are connected to each other by using a service-oriented interface. The user plane transmission channels established by different control plane network elements for transmitting data of multicast / broadcast services may be different. As a result, it is easy for data of the same multicast / broadcast service to be transmitted to terminals at the same frequency at the same time.

[0081] For example, in a 5G multicast / broadcast network architecture, in a multi-area multicast / broadcast session management function (MB-SMF) scenario, the same multicast / broadcast service is managed by different MB-SMFs. Based on the policy / control rules (policy / charging rules, PCC rules) of the multicast / broadcast service, the different MB-SMFs may bind / map the same service data flow (SDF) of the multicast / broadcast service to quality of service flows (QFs) with different quality of service flow identifiers (QoS flow identifiers, QFIs). As a result, an inconsistency problem occurs between QFIs bound / mapped to the same SDF. As a result, the QFIs sent by the MB-SMFs in different areas to access network devices and the quality of service profiles (QoS profiles) corresponding to those QFIs are different.

[0082] Furthermore, the access network device maps radio bearer resources (e.g., data radio bearers (DRBs) or multicast / broadcast radio bearers (MRBs)) based on the QoS profile corresponding to the QFI, and maps the QFI to a DRB ID or MRB ID. Because the QFIs received by different access network devices and the QoS profiles corresponding to these QFIs are different, different QFIs may be mapped to different radio bearer resources (e.g., DRBs or MRBs) under the management of different access network devices. In this case, data of the same multicast / broadcast service may be transmitted to a terminal by using different radio bearer resources. As a result, user plane data cannot be transmitted synchronously, access network devices across different areas cannot be ensured to be deployed in SFN, and data of the same multicast / broadcast service cannot be transmitted simultaneously in multiple areas on the same frequency. As a result, transmission of data of the multicast / broadcast service fails.

[0083] For example, MB-SMF1 in area A and MB-SMF2 in area B jointly manage multicast / broadcast service 1, where area A corresponds to base station 1 and area B corresponds to base station 2. MB-SMF1 in area A may bind / map SDF1 of the multicast / broadcast service to a QoS flow with a QoS flow ID of 3 based on the PCC rule of multicast / broadcast service 1, and base station 1 maps QF3 to DRB1 or MRB1. MB-SMF2 in area B may bind / map SDF1 to a QoS flow with a QoS flow ID of 7 based on the PCC rule of the multicast / broadcast service, and base station 2 maps QF7 to DRB2 or MRB2. In other words, SDF1 of multicast / broadcast service 1 is bound / mapped to QoS flows with different QoS flow IDs under the management of different MB-SMFs in different areas and transmitted to terminals by using different DRBs or MRBs.

[0084] To solve the aforementioned technical problems, an embodiment of the present application provides a multicast / broadcast service communication method. The method may include a first network element determining a QFI for a multicast / broadcast service and transmitting the QFI for the multicast / broadcast service to multiple session management function network elements. For example, the first network element transmits the QFI for the multicast / broadcast service to a first session management function network element and a second session management function network element. The first session management function network element receives the QFI and, based on the QFI, transmits the QFI and a QoS profile corresponding to the QFI to a first access network device. The second session management function network element receives the QFI for the multicast / broadcast service and, based on the QFI, transmits the QFI and a QoS profile corresponding to the QFI to a second access network device. That is, the first network element controlling the multicast / broadcast service in a centralized manner is deployed in a multicast / broadcast network architecture. The first network element generates a QFI for a multicast / broadcast service and distributes the QFI evenly to session management function network elements (e.g., MB-SMFs) in different areas, so that the session management function network elements in different areas can obtain the same QFI from the first network element and ensure consistency between the QFIs sent by the session management function network elements in different areas to access network devices and consistency between the QoS profiles corresponding to those QFIs, thereby ensuring that SFNs can be implemented between access network devices in different areas.

[0085] With reference to the accompanying drawings herein, the multicast / broadcast service communication method provided in this embodiment of the present application will be described hereinafter.

[0086] It should be understood that the network architectures and service scenarios described in the embodiments of the present application are intended to more clearly describe the technical solutions in the embodiments of the present application, and do not constitute limitations on the technical solutions provided in the embodiments of the present application. With the evolution of network architectures and the emergence of new service scenarios, those skilled in the art may know that the technical solutions provided in the embodiments of the present application can also be applied to similar technical problems.

[0087] 2 illustrates a communication system according to an embodiment of the present application. As illustrated in FIG. 2, the communication system may include a first network element, multiple session management function network elements (e.g., a first session management function network element and a second session management function network element), and multiple access network devices (e.g., a first access network device and a second access network device). The multiple session management function network elements may be located in separate areas, and the session management function network elements may be MB-SMFs or SMFs. Furthermore, the communication system may include a first mobility management network element, a second mobility management network element, a first user plane network element, a second user plane network element, a terminal, etc. The first user plane network element is connected to the first session management function network element and is managed / controlled by the first session management function network element. The second user plane network element is connected to the second session management function network element and is managed / controlled by the second session management function network element. The first access network device is connected to a first user plane network element, and the second access network device is connected to a second user plane network element.

[0088] In the following, the network elements or devices in the communication system shown in FIG. 2 are described.

[0089] The first network element may be configured to manage and control QoS information of the multicast / broadcast service in a centralized manner, e.g., QFI of the multicast / broadcast service. Specifically, the first network element may be a network exposure function (NEF) or a multicast / broadcast service function (MBSF), a network element obtained after both the NEF and the MBSF are deployed, or an unstructured data storage function (UDSF), another unnamed network element, etc.

[0090] Session Management Function The network element is mainly configured to implement session management functions such as establishing, releasing, and modifying user plane transmission logical channels, e.g., PDU sessions.

[0091] An access network device is mainly configured to implement functions such as physical layer functions, resource scheduling and management, and terminal access control and mobility management. The access network device may be a device supporting wired access or a device supporting wireless access. For example, the access network device may be an access network (AN) / radio access network (RAN), where the AN / RAN includes multiple 5G-AN / 5G-RAN nodes. The 5G-AN / 5G-RAN node may be an access point (AP), a Node B (NB), an enhanced Node B (eNB), a next-generation Node B (NR Node B, gNB), a transmission reception point (TRP), a transmission point (TP), or another access node.

[0092] The mobility management network element is mainly responsible for terminal access authentication, mobility management, and signaling exchange between functional network elements, such as managing user registration status, user connection status, user registration and network access, tracking area updates, user authentication during cell handover, and key security.

[0093] A terminal may be a device configured to implement wireless communication functions, such as a terminal or a chip capable of being used in the terminal. The terminal may be a UE, access terminal, terminal unit, terminal station, mobile station, mobile console, remote station, remote terminal, mobile device, wireless communication device, terminal agent, terminal equipment, etc. in a 5G network or future evolved communication system. An access terminal may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld or computing device with wireless communication capabilities, another processing device connected to a wireless modem, an in-vehicle device, or a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc. Terminals may be mobile or fixed.

[0094] A user plane network element may be used as an anchor on a user plane transmission logical channel and is configured to accomplish functions such as routing and forwarding of user plane data. For example, the user plane network element establishes a channel (i.e., a user plane transmission logical channel) between the user plane network element and a terminal, forwards data packets between the terminal and the DN on the channel, and is responsible for data packet filtering, data forwarding, rate control, and generating charging information for the terminal.

[0095] It should be noted that Fig. 2 is only an exemplary diagram of the architecture. In addition to the functional units shown in Fig. 2, the system may further include another functional network element, for example, an operation and management (O&M) network element. This is not limited in this embodiment of the present application. In addition, the names of the devices in Fig. 2 are not limited. In addition to the names shown in Fig. 2, the devices may also have other names. For example, the names may be replaced with the names of network elements having the same or similar functions. This is not limited.

[0096] 2 may be, but is not limited to, a 3rd generation partnership project (3GPP) communication system, such as a 4th generation (4G) communication system, a long term evolution (LTE) system, a 5th generation (5G) communication system, a new radio (NR) system, a next generation communication system, or a non-3GPP communication system.

[0097] It should be understood that the names of the same functional network elements in Figure 2 in different communication systems may be the same or different. For example, specifically, if the communication system shown in Figure 2 is a 4G communication system, the mobility management network element is a mobility management entity (MME). If the communication system shown in Figure 2 is a 5G communication system, the mobility management network element is an access and mobility management function (AMF).

[0098] For example, the communication system shown in Figure 2 is a 5G communication system shown in Figure 3. As shown in Figure 3, a network element or entity corresponding to the session management function network element may be a multicast / broadcast-session management function (MB-SMF) in the 5G communication system. A network element or entity corresponding to the user plane network element may be a user plane function (UPF) in the 5G communication system. A network element or entity corresponding to the access network device may be a radio access network (RAN) in the 5G communication system. A network element or entity corresponding to the mobility management network element may be an AMF in the 5G communication system. A terminal corresponds to a UE in the 5G communication system. A first network element corresponds to an MBSF in the 5G communication system.

[0099] Optionally, in this embodiment of the present application, network elements such as the first network element, the session management function network element (e.g., the first session management function network element and the second session management function network element), and the access network device (e.g., the first access network device and the second access network device) may also be referred to as communication devices, and each may be a general-purpose device or a dedicated device, which is not particularly limited in this embodiment of the present application.

[0100] Optionally, in this embodiment of the present application, the related functions of the first network element and the session management function network element (e.g., the first session management function network element and the second session management function network element) may be implemented by one device, may be jointly implemented by multiple devices, or may be implemented by one or more function modules in one device. This is not particularly limited in this embodiment of the present application. It may be understood that the aforementioned functions may be network elements in a hardware device, software functions running on dedicated hardware, a combination of hardware and software, or virtualized functions instantiated on a platform (e.g., a cloud platform).

[0101] During a specific implementation, all of the devices in the communication system, such as the first network element and the session management function network element (such as the first session management function network element and the second session management function network element), may use the configuration structure shown in FIG. 4 or may include the components shown in FIG. 4. FIG. 4 is a schematic diagram of the configuration of a communication device 400 according to an embodiment of the present application. The communication device 400 may include a processor 401, a communication line 402, and a communication interface 403. Furthermore, the communication device 400 may include a memory 404. The processor 401, the memory 404, and the communication interface 403 may be connected to each other through the communication line 402.

[0102] The processor 401 may be a central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 401 may alternatively be another device having processing capabilities, such as a circuit, a component, or a software module, without limitation.

[0103] The communication lines 402 are configured to transmit information between components included in the communication device 400 .

[0104] The communication interface 403 is configured to communicate with another device or another communication network. The other communication network may be an Ethernet, a radio access network (RAN), a wireless local area network (WLAN), etc. The communication interface 403 may be a module, a circuit, a transceiver, or any device capable of implementing communication.

[0105] The memory 404 is configured to store instructions, which may be a computer program.

[0106] Memory 404 may be, without limitation, read-only memory (ROM) or another type of static storage device capable of storing static information and / or instructions, random access memory (RAM) or another type of dynamic storage device capable of storing information and / or instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other compact disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, and Blu-ray optical discs), magnetic disc storage media, or another magnetic storage device.

[0107] It should be noted that the memory 404 may exist separately from the processor 401 or may be integrated into the processor 401. The memory 404 may be configured to store instructions, program code, some data, etc. The memory 404 may be located inside the communication device 400 or outside the communication device 400. This is not a limitation.

[0108] The processor 401 is configured to execute instructions stored in the memory 404 to implement a multicast / broadcast service communication method provided in a later-described embodiment of the present application. For example, if the communication device 400 is a session management function network element, or a chip or system-on-chip in a session management function network element, the processor 401 executes instructions stored in the memory 404 to implement steps performed by the session management function network element in a later-described embodiment of the present application. As another example, if the communication device 400 is a mobility management network element, or a chip or system-on-chip in a mobility management network element, the processor 401 executes instructions stored in the memory 404 to implement steps performed by the mobility management network element in a later-described embodiment of the present application.

[0109] In an example, processor 401 may include one or more CPUs, for example, CPU0 and CPU1 in FIG.

[0110] In an optional implementation, the communication device 400 includes multiple processors. For example, the communication device 400 may further include a processor 407 in addition to the processor 401 in FIG.

[0111] In an optional embodiment, the communication apparatus 400 further includes an output device 405 and an input device 406. For example, the input device 406 is a device such as a keyboard, a mouse, a microphone, or a joystick, and the output device 405 is a device such as a display screen or a speaker.

[0112] It should be noted that the communication device 400 may be a desktop computer, a portable computer, a network server, a mobile phone, a tablet computer, a wireless terminal, an embedded device, a chip system, or a device having a structure similar to that in Figure 4. Additionally, the configuration structure shown in Figure 4 does not constitute a limitation on the communication device. In addition to the components shown in Figure 4, the communication device may include more or fewer components than those shown in the figure, or some components may be combined, or a different component arrangement may be used.

[0113] In this embodiment of the present application, the chip system may include a chip, or may include a chip and other discrete components.

[0114] With reference to the communication system shown in FIG. 2 , a multicast / broadcast service communication method provided in an embodiment of the present application will be described below. A network element in the embodiment described below may have the components shown in FIG. 4 . Details will not be described again. It should be noted that actions, terms, etc. in the embodiments of the present application may be cross-referenced. This is not limiting. In the embodiments of the present application, the names of messages exchanged between devices, the names of parameters in those messages, etc. are merely examples. Other names may be used instead in a specific implementation. For example, multicast / broadcast in the embodiments of the present application may be replaced with groupcast, broadcast, or multicast. "Determining" in the embodiments of the present application may also be understood as creating or generating, and "including" in the embodiments of the present application may also be understood as conveying, etc. In this specification, the descriptions are provided equivalently. In the embodiments of the present application, details are not particularly limited.

[0115] 5 shows a multicast / broadcast service communication method according to an embodiment of the present application. As shown in FIG. 5, the method includes the following steps:

[0116] S501: A first network element determines a QFI for a multicast / broadcast service.

[0117] The first network element may be the NEF or the MBSF, or may be a network element, such as a UDSF, that is obtained after the NEF and MBSF are both deployed.

[0118] A multicast / broadcast service may be a service directed to multiple terminals (or user groups). For example, a multicast / broadcast service may be a command transmitted by the same command center or the same television program. Data of a multicast / broadcast service may be received by more than one terminal. If data of a multicast / broadcast service is directed to multiple terminals in a multicast / broadcast group, all terminals in the multicast / broadcast group may receive the data of the multicast / broadcast service after being acknowledged or without being acknowledged.

[0119] A QFI of a multicast / broadcast service may represent a quality of service flow (QoS flow, QF) to which a service data flow (SDF) of the multicast / broadcast service is mapped / bound, the quality of service requirements of the QF, etc. One type of multicast / broadcast service may correspond to one or more SDFs, one SDF may be mapped to one or more QFs, one QF corresponds to one QFI, and different QFs correspond to different QFIs. A multicast / broadcast service may have one or more QFIs. This is not limited.

[0120] For example, the first network element may determine the QFI of the multicast / broadcast service in the following manner 1 or manner 2.

[0121] Manner 1: A first network element obtains information about a multicast / broadcast service from an application server, and determines a QFI for the multicast / broadcast service based on the information about the multicast / broadcast service.

[0122] For example, an application server may send a first request carrying information about a multicast / broadcast service to a first network element, wherein the first network element receives the first request, obtains the information about the multicast / broadcast service from the first request, and determines a QFI for the multicast / broadcast service based on the information about the multicast / broadcast service.

[0123] The information about the multicast / broadcast service may include identifier information of the multicast / broadcast service and / or requirement information of the multicast / broadcast service. Specifically, the identifier information of the multicast / broadcast service may represent the multicast / broadcast service. The identifier information of the multicast / broadcast service may include, but is not limited to, a temporary mobile group identity (TMGI) of the multicast / broadcast group, an internet protocol (IP) address of an application server (e.g., an AF providing the multicast / broadcast service), a service identifier (service ID) of the multicast / broadcast service, identifier information of a multicast / broadcast protocol data unit (PDU) session corresponding to the multicast / broadcast group, or an identification rule of a service data flow (SDF) of the multicast / broadcast service.

[0124] Specifically, the requirement information of the multicast / broadcast service may include identifier information of the multicast / broadcast service, a type of the multicast / broadcast service, a requirement of the multicast / broadcast service (such as a bandwidth requirement or a delay requirement), information used by the core network device to authenticate the terminal (such as a generic public subscription identifier (GPSI) of the terminal), a service area of the multicast / broadcast service, a transmission start time and a transmission end time of the multicast / broadcast service, etc. The requirement information of the multicast / broadcast service may be for determining QoS information of the multicast / broadcast service.

[0125] The application server may be a content provider (CP) or an application function (APP server, AF). The application server may provide multicast / broadcast services to terminals.

[0126] The first request may be for requesting transmission resources corresponding to the multicast / broadcast service, for example, for requesting to establish a multicast / broadcast session corresponding to the multicast / broadcast service. Specifically, the first request may be a multicast / broadcast session establishment request or a multicast / broadcast session configuration request, or may be a multicast / broadcast session request, a multicast / broadcast session startup request, a multicast / broadcast session activation request, etc. This is not limited thereto.

[0127] The QoS information of the multicast / broadcast service may be the QoS information of the SDF of the multicast / broadcast service. The QoS information may be the 5th generation quality of service identifier (5 th The information may include one or more of information regarding quality of service identifier (5QI), allocation and retention priority (ARP), maximum flow bit rate (MFBR), and guaranteed flow bit rate (GFBR), and may further include charging policy information, other information, etc.

[0128] In a possible design, the information about the multicast / broadcast service includes identifier information of the multicast / broadcast service. The first network element's determining a QFI for the multicast / broadcast service based on the information about the multicast / broadcast service may include the first network element checking, based on the identifier information of the multicast / broadcast service, whether a QFI corresponding to the identifier information of the multicast / broadcast service exists locally. If a QFI corresponding to the identifier information of the multicast / broadcast service exists locally, the QFI corresponding to the identifier information of the multicast / broadcast service is determined as the QFI for the multicast / broadcast service. If a QFI corresponding to the identifier information of the multicast / broadcast service does not exist locally, the first network element sends the identifier information of the multicast / broadcast service to a PCF, obtains a PCC rule for the multicast / broadcast service from the PCF, and determines a QFI for the multicast / broadcast service based on the PCC rule. Furthermore, the first network element may store a correspondence between the identifier information of the multicast / broadcast service and the QFI.

[0129] In this possible design, see Mode 2 below for a related description of the PCC rule and the manner in which the first network element determines the QFI of the multicast / broadcast service based on the PCC rule.

[0130] In another possible design, the information about the multicast / broadcast service includes requirement information of the multicast / broadcast service. Determining a QFI for the multicast / broadcast service by the first network element based on the information about the multicast / broadcast service may include: determining, by the first network element, QoS information for the multicast / broadcast service based on the requirement information for the multicast / broadcast service; mapping / binding an SDF for the multicast / broadcast service to a QF based on the QoS information of the multicast / broadcast service, where the QoS information of the QF is the same as the QoS information of the SDF mapped / bound to the QF; and assigning the QFI to the QF, specifically, binding a correspondence between the QoS information of the SDF and the QFI, e.g., a correspondence between the QFI and a 5QI, an ARP, etc. in the information about the SDF.

[0131] It should be noted that in this possible design, if the first network element has received the multicast / broadcast service requirement information from the application server and determined the multicast / broadcast service QFI based on the multicast / broadcast service requirement information before receiving the multicast / broadcast service requirement information from the application server, after the first network element receives the multicast / broadcast service requirement information from the application server again, the first network element determines through comparison whether the multicast / broadcast service requirement information being received again is the same as the multicast / broadcast service requirement information previously received, i.e., whether the multicast / broadcast service requirement information has been updated. If the multicast / broadcast service requirement information has not been updated, the previously determined QFI is used as the multicast / broadcast service QFI in S501. If the multicast / broadcast service requirement information has been updated, another possible design manner is executed.

[0132] In yet another possible design, the information about the multicast / broadcast service includes identifier information of the multicast / broadcast service and requirement information of the multicast / broadcast service. The first network element determining a QFI for the multicast / broadcast service based on the information about the multicast / broadcast service may include the first network element determining QoS information for the multicast / broadcast service based on the requirement information for the multicast / broadcast service and determining a QFI for the multicast / broadcast service based on the QoS information for the multicast / broadcast service. For a determining manner, refer to the description of another possible design. Details will not be described again. Furthermore, the first network element stores a correspondence between identifier information for the multicast / broadcast service and a QFI for the multicast / broadcast service.

[0133] Manner 2: The first network element determines the QFI of the multicast / broadcast service based on the policy and charging control (PCC) rules of the multicast / broadcast service.

[0134] For related descriptions of PCC rules, please refer to descriptions in existing standards. For example, a PCC rule may include an SDF template, which may include one or more SDF filters, and the SDF filters are configured to obtain the SDF sent by the application server through filtering. The SDF module may further include QoS information of the SDF of multicast / broadcast service (alternatively referred to as QoS information of multicast / broadcast service). The QoS information of multicast / broadcast service is described in Format 1 and will not be described in detail again.

[0135] The PCC rule may be generated by the PCF based on the requirement information of the multicast / broadcast service and stored locally by the PCF. For example, the PCF may locally store the PCC rule of the multicast / broadcast service in association with the identifier information of the multicast / broadcast service. The requirement information of the multicast / broadcast service may be obtained by the PCF from an application server that provides the multicast / broadcast service. The relevant description of the requirement information of the multicast / broadcast service is described in the above-mentioned Form 1, and the details will not be described again.

[0136] Specifically, the first network element may obtain a PCC rule from a PCF, determine a filtered SDF based on an SDF template in the PCC rule, map / bind the SDF to a QF based on QoS information of the SDF, where the QoS information of the QF is the same as the QoS information of the SDF mapped / bound to the QF, and assign a QFI to the QF, specifically, bind the correspondence between the QoS information of the SDF and the QFI, for example, the correspondence between the 5QI, ARP, etc. in the information about the SDF and the QFI.

[0137] For example, a multicast / broadcast service is assumed to include SDF1, SDF2, and SDF3. The first network element may map / bind SDF1 and SDF2 to QF1 and map / bind SDF3 to QF2 in Manner 1 or Manner 2. In other words, the first network element determines that the QFI of the multicast / broadcast service includes QF1 and QF2. Furthermore, the first network element may further store a correspondence relationship between {QF1, QF2} and identifier information of the multicast / broadcast service.

[0138] S502: A first network element sends a QFI of a multicast / broadcast service to multiple session management function network elements.

[0139] For example, a first network element sends a QFI for a multicast / broadcast service to a first session management function network element, and sends a QFI for a multicast / broadcast service to a second session management function network element.

[0140] The session management function network element may be, but is not limited to, an MB-SMF or an SMF. The service ranges / areas of different session management function network elements may be different. For example, the service range / area of a first session management function network element is area A, and the service range / area of a second session management function network element is area B. Area B is different from area A, and the two areas do not overlap. The first session management function network element may be connected to a user plane network element in area A, manage the user plane network element in area A, and control the user plane network element in area A to establish a transmission channel for a multicast / broadcast service with an access network device in area A. The second session management function network element may be connected to a user plane network element in area B, manage the user plane network element in area B, and control the user plane network element in area B to establish a transmission channel for a multicast / broadcast service with an access network device in area B.

[0141] For example, a first network element may receive a request from a first session management function network element carrying identifier information of a multicast / broadcast service, and may transmit a QFI of the multicast / broadcast service to the first session management function network element based on the identifier information of the multicast / broadcast service and a locally stored correspondence between the identifier information of the multicast / broadcast service and the QFI. Similarly, the first network element may transmit a QFI of the multicast / broadcast service to a second session management function network element in this manner.

[0142] For example, the first network element may send the QFI of the multicast / broadcast service to the first session management function network element. In a possible design, the first network element may send the QFI of the multicast / broadcast service directly to the first session management function network element. In another possible design, the first network element may send the QFI of the multicast / broadcast service to the first session management function network element by using a PCF or another intermediate network element.

[0143] The PCF may be an MB-PCF that manages a first session management function network element. The first network element's sending of the QFI of the multicast / broadcast service to the first session management function network element by using the PCF may include, after receiving a request sent by the first session management function network element, carrying identifier information of the multicast / broadcast service, the first network element querying a binding support function (BSF) based on the identifier information of the multicast / broadcast service to obtain an MB-PCF that manages the multicast / broadcast service, and sending the identifier information of the multicast / broadcast service and the QFI of the multicast / broadcast service to the MB-PCF. The MB-PCF sends the QFI of the multicast / broadcast service to the MB-SMF based on the identifier information of the multicast / broadcast service.

[0144] The BSF stores the correspondence between the identifier information of the multicast / broadcast service and the identifier information of the PCF. A policy association is established between the PCF and the corresponding session management function network element (e.g., MB-SMF) that manages the multicast / broadcast service. The identifier information of the multicast / broadcast service and the identifier information of the session management function network element may be stored in a UDM in a corresponding manner. The PCF may send the identifier information of the multicast / broadcast service to the UDM, obtain the identifier information of the session management function network element from the UDM, and send a QFI of the multicast / broadcast service to the MB-SMF based on the identifier information of the session management function network element.

[0145] S503: The first session management function network element receives a QFI of a multicast / broadcast service, and sends the QFI and a QoS profile corresponding to the QFI to the first access network device based on the QFI.

[0146] The first access network device may be connected to a user plane network element managed / controlled by the first session management function network element, and the first access network device may establish a user plane transmission channel for transmitting data of the multicast / broadcast service between the first access network device and the user plane network element managed / controlled by the first session management function network element.

[0147] The QoS profile corresponding to a QFI may also be referred to as QoS setting information, QoS information, etc. The QoS profile corresponding to a QFI may represent information such as the transmission quality requirements of the QF identified by the QFI, such as the transmission bit rate, transmission delay, or priority of the QF. Specifically, the QoS profile corresponding to a QFI is the QoS information of an SDF bound to the QF identified by the QFI. The first session management function network element may obtain a binding relationship between the SDF and the QFI from the first network element, obtain the QoS information of the SDF from the first network element or the PCF, and use the QoS information of the SDF as the QoS profile corresponding to the QFI based on the binding relationship between the SDF and the QFI.

[0148] For example, the first session management function network element transmitting the QFI and a QoS profile corresponding to the QFI to the first access network device based on the QFI may include the first session management function network element determining a QoS profile corresponding to the QFI based on the QFI of the multicast / broadcast service, carrying the QFI and the QoS profile corresponding to the QFI in an N2 session management (N2 SM) message, and sending the N2 SM information to the first mobility management network element through Namf_Communication_N1N2MessageTransfer. The first mobility management network element receives the Namf_Communication_N1N2MessageTransfer, obtains N2 SM information carrying the QFI and the QoS profile corresponding to the QFI from the Namf_Communication_N1N2MessageTransfer, and sends the obtained N2 SM information to the first access network device.

[0149] Furthermore, the first access network device receives the N2 SM information, obtains a QFI and a QoS profile corresponding to the QFI from the N2 SM information, and configures radio bearer resources for transmitting data of the multicast / broadcast service based on the QoS profile corresponding to the QFI. The transmission quality requirements of the radio bearer resources satisfy the QoS profile corresponding to the QFI. The radio bearer resources may be for a DRB ID or an MRB ID. The radio resource bearer configuration may include, but is not limited to, one or more of a packet data convergence protocol (PDCP) layer configuration, a radio link control (RLC) layer configuration, a media access control (MAC) layer configuration, a physical (PHY) layer configuration, a logical channel configuration, a transmission channel configuration, or a physical channel configuration.

[0150] S504: The second session management function network element receives a QFI of the multicast / broadcast service, and sends the QFI and a QoS profile corresponding to the QFI to the second access network device based on the QFI.

[0151] For example, the QFI received by the second session management function network element is the same as the QFI received by the first session management function network element, and the QoS profile corresponding to the QFI sent by the second session management function network element to the second access network device is the same as the QoS profile sent by the first session management function network element to the first access network device.

[0152] Specifically, for the execution process of S504, please refer to S503, and the details will not be described again.

[0153] Furthermore, after receiving the QFI and the QoS profile corresponding to the QFI, the second access network device may configure radio bearer resources for transmitting data of the multicast / broadcast service based on the QoS profile corresponding to the QFI. For specific configuration processing, please refer to the processing of the first access network device configuring radio bearer resources for transmitting data of the multicast / broadcast service based on the QoS profile corresponding to the QFI. Details will not be described again.

[0154] 5, the first network element centrally determines a QFI for a multicast / broadcast service and distributes the QFI evenly to session management function network elements in different areas, so that different session management function network elements across the areas obtain the same QFI, determine the same QoS profile based on the same QFI, and send the QoS profile to access network devices in the service range / service area of the session management function network element. In this manner, the access network devices in different areas obtain the same QoS profile and establish the same radio bearer resource for transmitting data of the multicast / broadcast service based on the same QoS profile, thereby implementing SFN between the access network devices across the areas. In other words, data of the same multicast / broadcast service are transmitted simultaneously on the same frequency to ensure successful transmission of data of the multicast / broadcast service.

[0155] It can be seen that S501 is described by using an example in which the first network element directly determines the QFI of the multicast / broadcast service. Alternatively, the first network element may determine one or more of the following information: the number of QFs corresponding to the multicast / broadcast service, detection information of the SDF of the multicast / broadcast service, policy control information (such as 5QI, ARP, or charging policy information) of the multicast / broadcast service, PCC rule (such as QFI in the PCC rule), subset of the PCC rule (QFI in the subset of the PCC rule), etc. The first network element transmits the information to multiple MB-SMFs, so that the multiple MB-SMFs know based on the information that the QFIs of the multicast / broadcast service are the same and that the obtained QFIs correspond to the same QoS profile. In this manner, access network devices in different areas configure the same radio bearer resources for transmitting data of the multicast / broadcast service based on the QoS profile corresponding to the same QFI, ensuring the implementation of SFN.

[0156] The multicast / broadcast service detection information may be for filtering / detecting data distributed by an application server that is a multicast / broadcast service. Specifically, the multicast / broadcast service detection information may include quintuple information corresponding to a multicast / broadcast service. If the quintuple information in a received data packet is the same as the quintuple information corresponding to a multicast / broadcast service, the data in the data packet is considered to be data of a multicast / broadcast service, and the data packet is considered to be a data packet corresponding to a multicast / broadcast service. Otherwise, the data packet is considered to not carry data of a multicast / broadcast service and is not a data packet corresponding to a multicast / broadcast service.

[0157] Furthermore, in the implementation scenario shown in FIG. 5, the above method further includes: when the QoS information of the multicast / broadcast service is updated, the first network element determines the QFI of the multicast / broadcast service based on the updated QoS information, i.e., performs S501 to S504 again.

[0158] For example, an application server updates a configuration of a multicast / broadcast service, and the application server sends updated requirement information of the multicast / broadcast service to a first network element. The first network element may generate new QoS information based on the new requirement information, determine a new QFI based on the new QoS information, and send the new QFI to multiple session management function network elements.

[0159] In this manner, when the QoS information of the multicast / broadcast service is updated, the first network element updates the QFI of the multicast / broadcast service and sends the updated QFI to multiple MB-SMFs, so that the access network device configures radio bearer resources for transmitting data of the multicast / broadcast service based on the QoS profile corresponding to the updated QFI, and ensures that the configured radio bearer resources meet the transmission requirements of the multicast / broadcast service.

[0160] In relation to the 5G communication system shown in Figure 2, the method shown in Figure 5 will be described hereinafter by assuming that the first network element is an MBSF, the first session management function network element is an MB-SMF1, the second session management function network element is an MB-SMF2, the first access network device is a gNB1, and the second access network device is a gNB2.

[0161] 6 shows a multicast / broadcast service communication method according to an embodiment of the present application. As shown in FIG. 6, the method may include the following steps:

[0162] S601: The application server sends a first request to the MBSF.

[0163] The first request may carry identifier information of a multicast / broadcast service and / or requirement information of a multicast / broadcast service. For related descriptions of identifier information of a multicast / broadcast service and requirement information of a multicast / broadcast service, please refer to the description in S501.

[0164] For example, the application server may send the first request directly to the MBSF, or may send the first request to the MBSF via an intermediate network element. For example, if the MBSF and the NEF are not both deployed, in other words, if the MBSF and the NEF are deployed separately, the application server may send the first request to the NEF, and the NEF forwards the first request to the MBSF.

[0165] Optionally, to ensure system security, before the application server sends the first request to the MBSF, the application server may register information about the application server with the MBSF. For example, the application server may send a registration request to the MBSF, where the registration request carries identifier information of the multicast / broadcast service and identifier information of the application server. Furthermore, after receiving the registration request, the MBSF stores the identifier information of the application server in a local registration list, where the registration list corresponds to the multicast / broadcast service. For example, there is a correspondence between the registration list and the identifier information of the multicast / broadcast service. In this manner, after receiving the first request sent by the application server, the MBSF may query the registration list. If the application server is on the registration list, the MBSF identifies the application server as a legitimate device, receives the first request, and provides the application server with a network service.

[0166] S602: The MBSF receives a first request from an application server.

[0167] Optionally, the MBSF performs authentication and authorization for the application server. If the authentication and authorization are successful, the subsequent steps S603 to S608 are executed.

[0168] For example, the MBSF performing authentication and authorization for the application server may include the MBSF obtaining multicast / broadcast service identifier information from the first request, locating a locally stored registration list corresponding to the multicast / broadcast service identifier information based on the multicast / broadcast service identifier information, and checking whether the registration list includes the application server identifier information. If the registration list includes the application server identifier information, the authentication and authorization is successful. Otherwise, if the registration list does not include the application server identifier information, the authentication and authorization is unsuccessful.

[0169] S603: The MBSF determines the QFI for the multicast / broadcast service.

[0170] For the execution process of S603, please refer to the description in Form 1 of S501. The details will not be described again.

[0171] S604: The MBSF sends the QFI of the multicast / broadcast service to MB-SMF1, and sends the QFI of the multicast / broadcast service to MB-SMF2.

[0172] In an example, the MBSF may send a request message carrying identifier information of a multicast / broadcast service to a second network element (e.g., UDR or UDM), where the request message is for requesting an MB-SMF that supports the multicast / broadcast service. The second network element receives the request message and sends identifier information of MB-SMF1 and identifier information of MB-SMF2 to the MBSF. The MBSF sends a QFI of the multicast / broadcast service to MB-SMF1 via AMF1 based on the identifier information of MB-SMF1, and sends a QFI of the multicast / broadcast service to MB-SMF2 via AMF2 based on the identifier information of MB-SMF2.

[0173] In another example, the MBSF may query the BSF to obtain the MB-PCF and send the QFI of the multicast / broadcast service to the MB-PCF. The MB-PCF may obtain identifier information of MB-SMF1 and identifier information of MB-SMF2 from the second network element and send the QFI of the multicast / broadcast service to MB-SMF1 and MB-SMF2 based on the identifier information of MB-SMF1 and the identifier information of MB-SMF2.

[0174] The second network element stores context information of the multicast / broadcast service, and the context information of the multicast / broadcast service includes a correspondence between identifier information of the multicast / broadcast service and identifier information of the MB-SMF that supports the multicast / broadcast service.

[0175] S605: MB-SMF1 receives the QFI of the multicast / broadcast service and sends the QFI and the QoS profile corresponding to the QFI to gNB1 based on the QFI of the multicast / broadcast service.

[0176] Furthermore, MB-SMF1 configures a PDR, FAR, etc. corresponding to the multicast / broadcast service based on the QFI and other information of the multicast / broadcast service. MB-SMF1 allocates endpoint information (e.g., MB-UPF1's GTP-U and IP address) of MB-UPF1 based on the QFI of the multicast / broadcast service and notifies the application server of the allocated endpoint information of MB-UPF1, so that the application server transmits data of the multicast / broadcast service to MB-UPF1 based on the endpoint information of MB-UPF1. In addition, MB-SMF1 transmits the PDR, FAR, etc. of the multicast / broadcast service to MB-UPF1, so that MB-UPF1 establishes a transmission channel between MB-UPF1 and gNB1.

[0177] S606: The gNB1 receives the QFI and the QoS profile corresponding to the QFI, and configures radio bearer resources between the gNB1 and the terminal for transmitting data of the multicast / broadcast service based on the QoS profile corresponding to the QFI.

[0178] The radio bearer resource may be a DRB (or MRB).

[0179] Furthermore, gNB1 assigns an ID to the DRB (or MRB) and binds the QFI to the DRB ID (or MRB ID).

[0180] S607: MB-SMF2 receives the QFI of the multicast / broadcast service and sends the QFI and the QoS profile corresponding to the QFI to gNB2 based on the QFI of the multicast / broadcast service.

[0181] Furthermore, MB-SMF2 configures a PDR, FAR, etc. corresponding to the multicast / broadcast service based on the QFI and other information of the multicast / broadcast service. MB-SMF2 allocates endpoint information (e.g., the GTP-U and IP address of MB-UPF2) of MB-UPF2 based on the QFI of the multicast / broadcast service and notifies the application server of the allocated endpoint information of MB-UPF2, so that the application server transmits data of the multicast / broadcast service to MB-UPF2 based on the endpoint information of MB-UPF2. In addition, MB-SMF2 transmits the PDR, FAR, etc. of the multicast / broadcast service to MB-UPF2, so that MB-UPF2 establishes a transmission channel between MB-UPF2 and gNB2.

[0182] S608: The gNB2 receives the QFI and the QoS profile corresponding to the QFI, and configures radio bearer resources between the gNB2 and the terminal for transmitting data of the multicast / broadcast service based on the QoS profile corresponding to the QFI.

[0183] The radio bearer resource may be a DRB (or MRB).

[0184] Additionally, gNB2 assigns an ID to the DRB (or MRB) and binds the QFI to the DRB ID (or MRB ID).

[0185] 6, the MBSF centrally determines the QFI of a multicast / broadcast service and transmits the QFI equally to the MB-SMFs in different areas, so that the different MB-SMFs across the areas obtain the same QFI and transmit the same QoS profile corresponding to the QFI to the gNBs in different areas. Therefore, the gNBs across the areas establish the same radio bearer resources for transmitting data of the multicast / broadcast service based on the same QoS profile, thereby implementing SFN across the areas, in other words, transmitting data of the same multicast / broadcast service simultaneously on the same frequency.

[0186] The above description mainly describes the solutions provided in the embodiments of the present application in terms of interactions between nodes. It can be understood that, to implement the above-described functions, each network element, for example, the first network element or the session management function network element, includes a corresponding hardware structure and / or software module for implementing the respective functions. Those skilled in the art will readily recognize that the algorithm steps in the examples described in connection with the embodiments disclosed herein can be implemented in the form of hardware, software, or a combination of hardware and computer software in the methods of the embodiments of the present application. Whether the functions are performed by hardware or hardware driven by computer software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use various methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of the present application.

[0187] In the embodiments of the present application, the first network element or the session management function network element may be divided into functional modules based on the above-mentioned method examples. For example, each functional module may be obtained through division based on its corresponding function, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware or in the form of a software functional module. It should be noted that in the embodiments of the present application, the division into modules is an example and is merely a logical division of functions. In actual implementation, other division styles may be used.

[0188] 7 is a diagram of the structure of a communication device 70. The communication device 70 may be a first network element, a chip or system-on-chip in the first network element, or another device capable of implementing the functions of the first network element in the aforementioned method. The communication device 70 may be configured to perform the functions of the first network element in the aforementioned method embodiments. In a possible implementation, the communication device 70 shown in FIG. 7 includes a processing unit 701 and a transmitting unit 702.

[0189] The processing unit 701 is configured to determine a QFI for a multicast / broadcast service. For example, the processing unit 701 may be configured to support the communication device 70 in performing S501 or S603.

[0190] The sending unit 702 is configured to send the QFI of the multicast / broadcast service to multiple session management function network elements. For example, the sending unit 702 may be configured to support the communication device 70 in performing S502 or S604.

[0191] Specifically, all relevant contents of the steps in the above-mentioned method embodiments shown in Figures 5 and 6 can be cited in the functional descriptions of the corresponding functional modules. The details will not be described again in this specification. The communication device 70 is configured to perform the functions of the first network element in the multicast / broadcast service communication method shown in Figures 5 and 6 to achieve the same effects as those of the multicast / broadcast service communication method.

[0192] In another implementation, the communication device 70 shown in FIG. 7 includes a processing module and a communication module. The processing module is configured to control and manage the actions of the communication device 70. For example, the processing module may integrate the functions of the processing unit 701 and may be configured to support the communication device 70 in performing steps such as S501 or S603. The communication module may integrate the functions of the transmitting unit 702 and communicate with another network entity, for example, with a functional module or network entity shown in any of the communication systems in FIGS. 2 and 3. Furthermore, the communication device 70 may further include a storage module configured to store instructions and / or data. When the instructions are executed by the processing module, the processing module is enabled to implement the method on the side of the first network element.

[0193] The processing module may be a processor, a controller, a module, or a circuit. The processing module may implement or execute various exemplary logic blocks described in connection with the contents disclosed in the embodiments of the present application. The communication module may be a transceiver circuit, a pin, an interface circuit, a bus interface, a communication interface, etc. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication device 70 in this embodiment of the present application may be the communication device shown in FIG. 4.

[0194] 8 is a diagram of the structure of a communication device 80. The communication device 80 may be a session management function network element (e.g., a first session management function network element), a chip or system-on-chip in a session management function network element, another device capable of implementing the functions of the session management function network element in the aforementioned method, etc. The communication device 80 may be configured to perform the functions of the session management function network element in the aforementioned method embodiments. In a possible implementation, the communication device 80 shown in FIG. 8 includes a processing unit 801 and a transceiver unit 802.

[0195] The processing unit 801 is configured to control the transceiver unit 802 to receive a QFI of a multicast / broadcast service from a first network element, and to send the QFI and a QoS profile corresponding to the QFI to an access network device. For example, the processing unit 801 may be configured to support the communication device 80 in performing S503 and S504, or S605 and S607.

[0196] Specifically, all relevant contents of the steps in the above-mentioned method embodiments shown in Figures 5 and 6 can be cited in the functional descriptions of the corresponding functional modules. The details will not be described again in this specification. The communication device 80 is configured to perform the functions of the session management function network element in the multicast / broadcast service communication method shown in Figures 5 and 6. Therefore, the same effects as those of the above-mentioned multicast / broadcast service communication method can be achieved.

[0197] In another implementation, the communication device 80 shown in FIG. 8 includes a processing module and a communication module. The processing module is configured to control and manage the actions of the communication device 80. For example, the processing module may integrate the functions of the processing unit 801 and be configured to support the communication device 80 in performing steps such as S503 and S504, or S605 and S607. The communication module may integrate the functions of the transceiver unit 802 and communicate with another network entity, for example, with a functional module or network entity shown in any of the communication systems in FIGS. 2 and 3. Furthermore, the communication device 80 may further include a storage module configured to store instructions and / or data. When the instructions are executed by the processing module, the processing module is enabled to implement this method on the side of a session management function network element.

[0198] The processing module may be a processor, a controller, a module, or a circuit. The processing module may implement or execute various exemplary logic blocks described in connection with the contents disclosed in the embodiments of the present application. The communication module may be a transceiver circuit, a pin, an interface circuit, a bus interface, a communication interface, etc. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication device 80 in this embodiment of the present application may be the communication device shown in FIG. 4.

[0199] 9 is a diagram of the structure of a communication system according to an embodiment of the present application. As shown in FIG. 9, the communication system may include a first network element 90, a first session management function network element 91, and a second session management function network element 92. In addition, the communication system may further include a first access network device and a second access network device. It should be noted that FIG. 9 is only an example of the accompanying drawings. The network elements included in the communication system shown in FIG. 9 and the quantity of these network elements are not limited in this embodiment of the present application.

[0200] The first network element 90 has the functionality of the first network element in the manner shown in Figure 5 or Figure 6. The first session management function network element 91 and the second session management function network element 92 have the functionality of the first session management function network element and the second session management function network element in the manner shown in Figure 5 or Figure 6.

[0201] In a multicast / broadcast communication scenario, the following problem further exists: A terminal may move and perform a cell handover, for example, a handover from one access network device to another access network device. The terminal obtains radio bearer configuration information of the multicast / broadcast service only after the terminal enters a target cell from a source cell, and can receive data of the multicast / broadcast service based on the obtained radio bearer configuration information corresponding to the multicast / broadcast service. As a result, the multicast / broadcast service being performed by the terminal is interrupted.

[0202] For example, for a cell in single-cell point-to-multipoint (SC-PTM) mode, only after entering the target cell does the UE read a system message (e.g., master information block (MIB)-system information block 1 (SIB1-SIB20)), obtain the location of the single-cell multicast-control channel (SC-MCCH) (e.g., the location of the SC-MCCH in the time and frequency domains) from the system message, obtain single-cell point-to-multipoint configuration (SCPTM Configuration) information at the time-frequency location of the SC-MCCH, obtain a single-cell multicast-radio bearer (SC-MRB) configuration from the SCPTM Configuration information, and receive data of the multicast / broadcast service based on the SC-MRB configuration. The multicast / broadcast service is suspended during the time until the UE enters the target cell and obtains the radio bearer configuration information corresponding to the multicast / broadcast service.

[0203] For another example, for a multicast / broadcast single frequency network (MBSFN) cell, only after entering the target cell, the UE reads MIB-SIB1-SIB13-SystemInformationBlockType13, obtains multicast control channel (MCCH) location information (e.g., the location of the MCCH in the time domain and the frequency domain) from MIB-SIB1-SIB13-SystemInformationBlockType13, obtains groupcast / multicast single frequency network area configuration (MBSFNAreaConfiguration) information at the location of the MCCH, obtains an MRB configuration from the MBSFNAreaConfiguration information, and receives data of the multicast / broadcast service based on the MRB configuration. The multicast / broadcast service is suspended during the time period from when the UE enters the target cell until it obtains radio bearer configuration information corresponding to the multicast / broadcast service.

[0204] To avoid interruption of a multicast / broadcast service when a terminal performs cell handover, an embodiment of the present application provides a multicast / broadcast service communication method. The method may include a target access network device allocating resources of a multicast / broadcast session to a terminal. The multicast / broadcast session is for transmitting data of the multicast / broadcast service. The target access network device transmits first configuration information. The first configuration information indicates resources of the multicast / broadcast session, and the first configuration information is used by the terminal to synchronize with the multicast / broadcast session after being handed over to the target access network device. A source access network device obtains the first configuration information and transmits the first configuration information to the terminal. The terminal receives the first configuration information from the source access network device and receives data of the multicast / broadcast service from the target access network device by using the multicast / broadcast session and based on the first configuration information. In this manner, before or during the terminal is handed over to the target access network device, resources for the multicast / broadcast session may be allocated to / configured for the terminal in advance, so that after the terminal is handed over to the target access network device, the terminal can continue to transmit data for the multicast / broadcast service by using the allocated resources of the multicast / broadcast session, thereby reducing interruption delay of the multicast / broadcast service.

[0205] An access network device corresponding to a source cell may be referred to as a source access network device, and an access network device corresponding to a target cell may be referred to as a target access network device. The source cell and the target cell may correspond to the same access network device or different access network devices. This is not limited. In this embodiment of the present application, if the source cell and the target cell correspond to different access network devices, the radio access technologies (RATs) supported by the different access network devices may be the same or different. In this embodiment of the present application, the RAT may include LTE technology or NR technology.

[0206] Hereinafter, the aforementioned multicast / broadcast service communication method will be described with reference to the accompanying drawings in this specification.

[0207] 10 shows a communication system according to an embodiment of the present application. As shown in FIG. 10, the communication system may include a source access network device, a target access network device, and a terminal. The source access network device may be an access network device connected to a terminal before the terminal performs cell handover, and the target access network device may be an access network device connected to a terminal after the terminal performs cell handover. The source access network device and the target access network device may be located in the same communication system or in different communication systems.

[0208] For example, both the source access network device and the target access network device may be located in the 5G communication system shown in Figure 11a. Alternatively, as shown in the 4G-5G interworking system shown in Figure 11b, the source access network device is located in the 4G communication system and the target access network device is located in the 5G communication system. Alternatively, the source access network device is located in the 5G communication system and the target access network device is located in the 4G communication system.

[0209] The following describes each network element or device in FIG.

[0210] The source access network device or target access network device is mainly configured to implement functions such as physical layer functions, resource scheduling and management, and terminal access control and mobility management. The source access network device or target access network device may be a device supporting wired access or a device supporting wireless access. For example, the source access network device may be a next-generation radio access network (NG-RAN) device or an access network (AN) / radio access network (RAN), including multiple 5G-AN / 5G-RAN nodes. The 5G-AN / 5G-RAN nodes may be next-generation NodeBs (gNBs), transmission reception points (TRPs), transmission points (TPs), or other access nodes. The target access network device may be an evolved universal terrestrial radio access network (E-UTRAN) device, such as an access point (AP), a Node B (NB), an enhanced Node B (eNB), or another access node.

[0211] A terminal may be a device configured to implement wireless communication functions, such as a terminal or a chip capable of being used in the terminal. A terminal may be a user equipment (UE), an access terminal, a terminal unit, a terminal station, a mobile station, a remote station, a remote terminal, a mobile device, a wireless communication device, a terminal agent, a terminal device, etc. in a 5G network or a future evolved communication system. An access terminal may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld or computing device with wireless communication capabilities, another processing device connected to a wireless modem, an in-vehicle device, or a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc. Terminals may be mobile or fixed.

[0212] It should be noted that Figure 10 is only an example of an architecture diagram. In addition to the functional units shown in Figure 10, the system may further include other functional network elements, such as a mobility management network element, a user plane network element, a policy control network element, and an operation and management (O&M) network element. This is not limited in this embodiment of the present application. In addition, the names of the devices in Figure 10 are not limited. In addition to the names shown in Figure 10, the devices may also have other names. For example, the names may be replaced with names of network elements having the same or similar functions. This is not limited.

[0213] For example, the source access network device and the target access network device are located in a 5G communication system. As shown in Figure 11a, the terminal corresponds to a UE in the 5G communication system shown in Figure 11a, the source access network device corresponds to an S-gNB in the 5G communication system shown in Figure 11a, and the target access network device corresponds to a T-gNB in the 5G communication system shown in Figure 11a. The S-gNB and the T-gNB may access the same AMF or different AMFs. When the S-gNB and the T-gNB may access different AMFs, the AMF accessed by the S-gNB may be referred to as a source AMF (or S-AMF), and the AMF accessed by the T-gNB may be referred to as a target AMF (or T-SMF). Furthermore, the system shown in Figure 11a may further include network elements such as an SMF and a UPF.

[0214] For example, the source access network device and the target access network device are located in separate communication systems. Figure 11b shows a 4G-5G interworking system including a packet data network (PDN) gateway user plane function (PGW-U) + UPF, a PDN gateway control plane function (PGW-C) + SMF, a session management function (SMF), a user plane function (UPF), a policy control function (PCF), a network exposure function (NEF), an access and mobility management function (AMF), an MME, an NRF, a UDR, or a UDM. When a terminal is handed over from a 4G system to a 5G system, a network element or entity corresponding to a source access network device may be an E-UTRAN, a network element or entity corresponding to a target access network device may be an NG-RAN, a network element or entity corresponding to a target mobility management network element may be an AMF, and a network element or entity corresponding to a source mobility management network element may be an MME. When a terminal is handed over from a 5G system to a 4G system, a network element or entity corresponding to a source access network device may be an NG-RAN, a network element or entity corresponding to a target access network device may be an E-UTRAN, a network element or entity corresponding to a target mobility management network element may be an MME, and a network element or entity corresponding to a source mobility management network element may be an AMF.Note that the "+" in the system shown in Figure 11b indicates co-expansion.

[0215] Optionally, the source access network device, the target access network device, and the terminal in this embodiment of the present application may also be referred to as communication devices, and each may be a general-purpose device or a dedicated device, which is not particularly limited in this embodiment of the present application.

[0216] Optionally, the related functions of the source access network device, the target access network device, and the terminal in this embodiment of the present application can be implemented by one device, jointly implemented by multiple devices, or implemented by one or more function modules in one device. This is not particularly limited in this embodiment of the present application. It can be understood that the aforementioned functions can be network elements in a hardware device, software functions running on dedicated hardware, a combination of hardware and software, or virtualized functions instantiated on a platform (e.g., a cloud platform).

[0217] In a specific implementation, devices in a communication system, such as a source access network device, a target access network device, and a terminal, may use the configuration structure shown in Figure 4 or may include the components shown in Figure 4. Details will not be described again.

[0218] With reference to the communication system shown in Figure 10, the multicast / broadcast service communication method provided in the embodiment of the present application will be described hereinafter. The network elements in the embodiment described below may include the components shown in Figure 4. The details will not be described again.

[0219] 12 is a flowchart of a multicast / broadcast service communication method according to an embodiment of the present application. As shown in FIG. 12, the method may include the following steps:

[0220] S1201: A target access network device allocates resources for a multicast / broadcast session to a terminal.

[0221] The transmission mode of the target access network device may be an SC-PTM mode or an MBSFN mode. If the terminal performs cell handover in a 5G communication system, the target access network device may be a T-gNB in FIG. 11a. Alternatively, if the terminal is handed over from a 4G system to a 5G system, the target access network device may be an NG-RAN in FIG. 11b. If the terminal is handed over from a 5G system to a 4G system, the target access network device may be an E-UTRAN in FIG. 11b. This is not limited.

[0222] The multicast / broadcast session may be for transmitting data of a multicast / broadcast service. Resources of the multicast / broadcast session may include time-frequency resources / radio bearer resources of the multicast / broadcast session, such as DRBs or MRBs.

[0223] For example, the target access network device allocating resources for the multicast / broadcast session to the terminal may include the target access network device receiving information about the multicast / broadcast service and allocating resources for the multicast / broadcast session to the terminal based on the information about the multicast / broadcast service.

[0224] The information about the multicast / broadcast service may include identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service. For related descriptions of the identifier information of the multicast / broadcast service and the QoS information of the multicast / broadcast service, please refer to the descriptions in Figure 12. The details will not be described again. The target access network device may receive the information about the multicast / broadcast service from the source access network device, or may receive the information about the multicast / broadcast service from a mobility management network element (e.g., a target mobility management network element).

[0225] In a possible design, the information about the multicast / broadcast service includes identifier information of the multicast / broadcast service. Allocating resources for the multicast / broadcast session to the terminal by the target access network device based on the information about the multicast / broadcast service may include the target access network device checking whether resources for the multicast / broadcast session are available based on the identifier information of the multicast / broadcast service. If resources for the multicast / broadcast session are unavailable, the target access network device sends the identifier information of the multicast / broadcast service to a PCF via a mobility management network element, obtains QoS information for the multicast / broadcast service, and allocates resources for the multicast / broadcast session to the terminal based on the QoS information of the multicast / broadcast service.

[0226] The multicast / broadcast session resources satisfy the transmission requirements of the multicast / broadcast service, as represented by the QoS information of the multicast / broadcast service. The multicast / broadcast session resources may also be referred to as radio bearer resources corresponding to the multicast / broadcast service. The multicast / broadcast session resources may be identified by a DRB ID or an MRB ID. The associated configuration of the multicast / broadcast session resources may include, but is not limited to, one or more of a PDCP layer configuration, an RLC layer configuration, a MAC layer configuration, a PHY layer configuration, a logical channel configuration, a transmission channel configuration, a physical channel configuration, etc.

[0227] In another possible design, the information about the multicast / broadcast service includes QoS information of the multicast / broadcast service. The target access network device's allocating of resources for the multicast / broadcast session to the terminal based on the information about the multicast / broadcast service may include allocating resources for the multicast / broadcast session to the terminal based on the QoS information of the multicast / broadcast service. The specific processing has been described above and will not be described in detail again.

[0228] In yet another possible design, the information about the multicast / broadcast service includes identifier information of the multicast / broadcast service and QoS information of the multicast / broadcast service. The target access network device's allocation of resources for the multicast / broadcast session to the terminal based on the information about the multicast / broadcast service may include allocating resources for the multicast / broadcast session to the terminal based on the QoS information of the multicast / broadcast service. The specific process has been described above and will not be described in detail again. Furthermore, the first network element stores a correspondence between the identifier information of the multicast / broadcast service and the resources for the multicast / broadcast session.

[0229] S1202: The target access network device sends first configuration information.

[0230] The first configuration information may represent resources of the multicast / broadcast session, and the first configuration information is used by the terminal to synchronize with the multicast / broadcast session after the terminal is handed over to the target access network device. The first configuration information may be a configuration of a set of air interface resources (including a PDCP layer configuration, an RLC layer configuration, a MAC layer configuration, a PHY layer configuration, a logical channel configuration, a transmission channel configuration, a physical channel configuration, etc.) corresponding to radio bearer resources for transmitting data of the multicast / broadcast service (e.g., a DRB or an MRB corresponding to the multicast / broadcast service).

[0231] For example, if the transmission mode of the target access network device is an SC-PTM mode, the first configuration information may be SCPTMConfiguration information, which may include single-cell multicast traffic channel (SC-MTCH) information, and the SC-MTCH information may include information about a multicast / broadcast session (mbms-SessionInfo) and a group-radio network temporary identifier (g-RNTI).

[0232] For another example, if the transmission mode of the target access network device is a multicast / broadcast single-frequency MBSFN mode, the first configuration information may be MBSFNAreaConfiguration information, which may include physical multicast channel information (PMCH-Info), and the PMCH information includes a PMCH configuration (pmch-Config) and a multicast / broadcast session list (mbms-SessionInfoList).

[0233] Each pmch-Config includes mch-SchedulingPeriod, dataMCS, etc. mch-SchedulingPeriod indicates the scheduling period of the physical multicast channel (PMCH). For example, if mch-SchedulingPeriod is set to rf8, it indicates eight radio frames, in other words, eight radio frames (in this case, each frame is 10 ms, for example). dataMCS indicates the number of bits that can be carried by each symbol in the modulation / coding scheme for the PMCH. For example, 16-quadrature amplitude modulation (QAM) indicates that each symbol can carry four bits. Specifically, one subframe in NR includes 14 symbols, and one subframe in LTE includes seven symbols.

[0234] The mbms-SessionInfoList contains information about multicast / broadcast sessions (mbms-SessionInfo) and the amount of mbms-SessionInfo carried on the PMCH. Each mbms-SessionInfo contains at least a TMGI, a logical channel identifier, etc.

[0235] For example, the target access network device may directly or indirectly send the first configuration information to the source access network device through a handover request response (handover request ACK) or a handover command.

[0236] For example, the target access network device may send a handover request response to the mobility management network element, where the handover request response carries the first configuration information, so that after receiving the first configuration information, the mobility management network element sends the first configuration information to the source access network device. The mobility management network element may be referred to as a target mobility management network element.

[0237] Specifically, when the terminal performs an inter-base station cell handover in a 5G communication system, the mobility management network element may be a T-AMF. For this transmission manner, refer to the description in the later-described embodiment corresponding to FIG. 14. Alternatively, when the terminal is handed over from a 5G system to a 4G system, the mobility management network element may be an MME. For this transmission manner, refer to the description in the later-described embodiment corresponding to FIG. 15A and FIG. 15B. Alternatively, when the terminal is handed over from a 4G system to a 5G system, the mobility management network element may be an AMF. For this transmission manner, refer to the description in the later-described embodiment corresponding to FIG. 17A and FIG. 17B or FIG. 18A and FIG. 18B.

[0238] For another example, the target access network device may directly send a handover request response to the source access network device, and the handover request response carries the first setting information. Specifically, for this manner, please refer to the description in the embodiment corresponding to Figure 13 or Figure 16.

[0239] S1203: The source access network device obtains first configuration information.

[0240] The source access network device may receive the first configuration information from a mobility management network element, or may receive the first configuration information from a target access network device.

[0241] S1204: The source access network device sends first configuration information to the terminal.

[0242] For example, the first configuration information may be transmitted to the terminal through a handover command.

[0243] S1205: The terminal receives first configuration information from the source access network device, and receives data belonging to the multicast / broadcast service coming from the target access network device by using the multicast / broadcast session and based on the first configuration information.

[0244] Based on the method shown in FIG. 12 , the target access network device pre-configures, for the terminal, resources of a multicast / broadcast session for transmitting data of the multicast / broadcast service, and sends the configuration result to the terminal via the source access network device, so that the terminal transmits data of the multicast / broadcast service by using the pre-configured resources of the multicast / broadcast session as soon as possible after the terminal is handed over to the target access network device, thereby reducing the interruption delay of the multicast / broadcast service and improving the transmission efficiency of the multicast / broadcast service.

[0245] In relation to the 5G communication system shown in Figure 11a, the method shown in Figure 12 will be described hereinafter using Xn handover between 5G MBS base stations as an example, assuming that the terminal is a UE, the source access network device is an S-gNB, the target access network device is a T-gNB, and the S-gNB and T-gNB access the same AMF.

[0246] 13 shows a multicast / broadcast service communication method according to an embodiment of the present application. As shown in FIG. 13, the method may include the following steps:

[0247] S1301: The UE sends a measurement report to the S-gNB.

[0248] The measurement report may include signal quality measurements of one or more cells and cell identities of one or more cells obtained by the terminal through measurements. The one or more cells may include a cell on which the UE is currently camped and neighboring cells of the cell on which the UE is currently camped. The signal quality may include any one or more of a reference signal received power (RSRP), a reference signal received quality (RSRQ), and a signal to interference plus noise ratio (SINR).

[0249] For example, the UE may receive RRC measurement configuration information sent by the S-gNB, measure one or more measurement objects (MOs) based on the RRC measurement configuration information, where the measurement targets include one or more cells, and send a measurement report to the S-gNB.

[0250] S1302: The S-gNB receives the measurement report, and based on the measurement report, decides to hand over the UE to the T-gNB, and sends a handover request to the T-gNB.

[0251] The S-gNB's determining to hand over the UE to the T-gNB based on the measurement report may include the S-gNB selecting, as the T-gNB, a base station corresponding to a cell having the greatest measured value of signal quality from the measured values of signal quality of one or more cells based on the measurement report. Alternatively, when the UE joins a multicast / broadcast group, the S-gNB selects, as the T-gNB, a base station that supports the multicast / broadcast group and has the highest signal quality from the measured values of signal quality of one or more cells.

[0252] The handover request includes PDU session information of the UE. The PDU session information includes a PDU session identifier of the UE and QoS information of a unicast service transmitted in the PDU session. For example, the QoS information of the unicast service may include a QFI of the unicast service and QoS parameters corresponding to the QFI of the unicast service. The QoS parameters corresponding to the QFI of the unicast service are used by the T-gNB to perform air interface resource configuration, and the QFI of the unicast service is indexed by the 5QI.

[0253] In this embodiment of the present application, the PDU session of the UE is associated with a multicast / broadcast service. When the PDU session of the UE is associated with a multicast / broadcast service, the PDU session information further includes identifier information of the multicast / broadcast service associated with the PDU session of the UE and / or QoS information of the multicast / broadcast service. The QoS information of the multicast / broadcast service may include a QFI of the multicast / broadcast service and QoS parameters corresponding to the QFI of the multicast / broadcast service. The QoS parameters corresponding to the QFI of the multicast / broadcast service are used by the T-gNB to perform resource configuration of the multicast / broadcast session.

[0254] The association of a UE's PDU session with a multicast / broadcast service may include the following two cases: First, the UE joins a multicast / broadcast session corresponding to a multicast / broadcast service by using control plane signaling of the PDU session. For example, the UE joins a multicast / broadcast session when requesting to establish / modify a PDU session. The UE sends a PDU session establishment request or a PDU session modification request to the SMF via the S-gNB and the AMF. The N1 Session Management Container (N1 SM Container) of the PDU session establishment request or PDU session modification request carries identifier information of the multicast / broadcast service. After receiving the PDU session establishment request or PDU session modification request, the SMF establishes or modifies the UE's PDU session, establishes a multicast / broadcast session based on the identifier information of the multicast / broadcast service, and returns a PDU session establishment response or a PDU session modification response to the UE. The PDU session establishment response or the PDU session modification response may carry identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service. So far, the UE's PDU session is associated with the multicast / broadcast service. Second case: Data of the multicast / broadcast service is transmitted to the UE by using the UE's PDU session. For example, when the S-gNB does not support MBS, data of the multicast / broadcast service can be transmitted by using the UE's PDU session. In this case, the UE's PDU session is associated with the multicast / broadcast service. However, when the S-gNB supports MBS, the UE's PDU session is for transmitting only unicast data, and data of the multicast / broadcast service is transmitted by using the multicast / broadcast session.In this case, the UE's PDU session is not associated with a multicast / broadcast service.

[0255] S1303: The T-gNB receives a handover request and obtains PDU session information from the handover request. The T-gNB prepares / configures / allocates resources for / to the UE of a PDU session intended for transmitting data of the unicast service based on QoS information for the unicast service carried in the PDU session information. The T-gNB prepares / configures / allocates resources for / to the UE of a multicast / broadcast session intended for transmitting data of the multicast / broadcast service based on identifier information of the multicast / broadcast service and / or the QoS information of the multicast / broadcast service carried in the PDU session information, and sends a handover request response (Handover Request ACK) to the S-gNB.

[0256] Specifically, the T-gNB preparing / configuring / allocating resources of a PDU session for transmitting data of the unicast service for / to a UE based on the QoS information of the unicast service may include the T-gNB determining, based on QoS parameters corresponding to the QFIs of the unicast service, data radio bearers (DRBs) for transmitting data of the unicast service and a mapping relationship between the QFIs and DRB IDs of the unicast service. The T-gNB may also determine configuration parameters corresponding to the DRBs (e.g., whether an acknowledged mode or an unacknowledged mode is used for a radio link control (RLC) layer corresponding to the DRB) based on the QoS parameters corresponding to the QFIs to which each DRB is mapped.

[0257] For the process in which the T-gNB allocates resources for the multicast / broadcast session to the UE based on the identifier information of the multicast / broadcast service and / or the QoS information of the multicast / broadcast service, please refer to the description in step 1201. The details will not be described again.

[0258] The handover request response includes configuration information of a PDU session for transmitting data of a unicast service and may include first configuration information.

[0259] The PDU session configuration information may be used by the UE to receive data of the unicast service. For example, the PDU session configuration information may be a set of air interface resource configurations, such as a PDCP layer configuration, an RLC layer configuration, a MAC layer configuration, a PHY layer configuration, a logical channel configuration, a transmission channel configuration, and a physical channel configuration, corresponding to a radio bearer resource (e.g., a unicast DRB ID) for transmitting data of the unicast service.

[0260] For the related description of the first setting information, please refer to the description in S1202. The details will not be described again.

[0261] It should be noted that in this application, the first configuration information is not limited to being carried in the handover request response. Alternatively, the T-gNB may send the first configuration information to the S-gNB by using separate signaling. This is not limited.

[0262] S1304: The S-gNB receives the handover request message and sends a handover command to the UE.

[0263] The handover command may indicate to the UE to hand over to the T-gNB. The handover command may carry identifier information of the T-gNB, PDU session configuration information, and first configuration information.

[0264] It should be noted that in the present application, the first setting information is not limited to being carried in the handover command, and the first setting information may alternatively be sent to the terminal through other information, but this is not limited thereto.

[0265] In this manner, the T-gNB transmits configuration information of the T-gNB's PDU session and first configuration information to the UE via the S-gNB, so that after accessing the T-gNB at S1305, the UE receives data that is a unicast service transmitted in the PDU session based on the configuration information of the PDU session, and receives data that is a multicast / broadcast service transmitted on the multicast / broadcast session based on the first configuration information.

[0266] S1305: The UE receives a handover command, and in response to the handover command, accesses the T-gNB based on identifier information of the T-gNB in the handover command, receives data of a unicast service transmitted in the PDU session based on configuration information of the PDU session carried in the handover command, and receives data of the multicast / broadcast service from the T-gNB based on first configuration information carried in the handover command by using the multicast / broadcast session.

[0267] S1306: T-gNB sends an N2 path switch request to AMF.

[0268] The N2 path switch request may include QFIs of unicast services that have been successfully switched in the PDU session and QFIs of unicast services that have failed to be switched in the PDU session. The N2 path switch request may be encapsulated in N2 SM information. Furthermore, the N2 path switch request may further include identifier information of the PDU session tunnel allocated by the T-gNB.

[0269] S1307: The AMF sends a PDU session context update request to the SMF.

[0270] The PDU session context update request (Nsmf_PDUSession_UpdateSMContext request) may include information included in the N2 SM information in S1306.

[0271] S1308: The SMF sends an N4 session update request to the UPF.

[0272] The N4 session update request may carry identifier information of a PDU session tunnel allocated by the T-gNB. Optionally, the N4 session update request may further include identifier information of a PDU session tunnel allocated by the SMF to the UPF. The PDU session tunnel identifier information is for establishing a PDU session tunnel between the T-gNB and the UPF.

[0273] S1309: The SMF sends a PDU session context update response to the AMF.

[0274] Optionally, the PDU session context update response (Nsmf_PDUSession_UpdateSMContext response) carries identifier information of the PDU session tunnel assigned by the SMF to the UPF.

[0275] Further, the N2 handover procedure shown in S1310 and S1311 is performed.

[0276] S1310: AMF sends an N2 path switch response (N2 path switch request ACK) to T-gNB.

[0277] The N2 path switch response may include identifier information of the PDU session tunnel assigned to the UPF by the SMF.

[0278] S1311: The T-gNB sends a UE context release request to the S-gNB.

[0279] In response, the S-gNB receives a UE context release request and releases PDU session resources, other resources, etc. for the UE based on the UE context release request.

[0280] Based on the method shown in FIG. 13, in a 5G communication system, information about a multicast / broadcast service (e.g., identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service) is transmitted in advance to the T-gNB through interaction on the Xn interface between the S-gNB and the T-gNB, whereby the T-gNB pre-configures, for the terminal, resources of a multicast / broadcast session for transmitting data of the multicast / broadcast service. Therefore, as soon as possible after the terminal is handed over to the T-gNB, the terminal transmits data of the multicast / broadcast service by using the resources of the pre-configured multicast / broadcast session, thereby reducing interruption delay of the multicast / broadcast service.

[0281] In Figure 13, the multicast / broadcast service communication method provided in this embodiment of the present application will be described by using an example in which the S-gNB and the T-gNB access the same AMF. Still referring to the 5G communication system shown in Figure 11a, the multicast / broadcast service communication method provided in the embodiment of the present application will be described by using an example in which the S-gNB and the T-gNB access different AMFs, for example, the S-gNB accesses the S-AMF and the T-gNB accesses the T-AMF.

[0282] 14 shows a multicast / broadcast service communication method according to an embodiment of the present application. As shown in FIG. 14, the method may include the following steps:

[0283] S1401: The UE transmits a measurement report to the S-gNB.

[0284] The execution process of S1401 is the same as that of S1301, and the details will not be described again.

[0285] S1402: The S-gNB receives the measurement report, and determines to hand over the UE to the T-gNB based on the measurement report, and determines a handover requirement ment ) to the source AMF (source AMF, S-AMF).

[0286] The handover requirement may include a target identifier (target ID) and information about the UE's PDU session. The target ID is the identifier information of the target cell to which the UE should be handed over, and the target ID may represent the target cell. For a related description of the target ID, please refer to the description in 3GPP Technical Specification (TS) 38413.

[0287] The information about the UE's PDU session may include an identifier of the UE's PDU session, QoS information of the unicast service transmitted in the PDU session, and identifier information and / or QoS information of the multicast / broadcast service associated with the UE's PDU session. Specifically, for related descriptions of the information about the UE's PDU session, please refer to the description in S1302. Details will not be described again.

[0288] Furthermore, when there is no direct forwarding tunnel between the S-gNB and the T-gNB, N2 SM information including indirect forwarding tunnel information allocated by the S-gNB is further required for handover. The indirect forwarding tunnel information allocated by the S-gNB is for establishing an indirect forwarding tunnel between the S-gNB and the T-gNB.

[0289] For the process by which the S-gNB decides to hand over the UE to the T-gNB, please refer to the description in S1302. The details will not be described again.

[0290] S1403: The S-AMF receives a handover requirement and selects a target AMF (target-AMF, T-AMF) based on the target ID carried in the handover requirement, where the T-AMF is connected to the T-gNB.

[0291] S1404: The S-AMF sends a UE context generation request to the T-AMF.

[0292] The UE context creation request (Namf_Communication_CreateUEContext request) may include UE context information stored in the S-AMF and information about the UE's PDU session sent by the S-gNB to the S-AMF at S1402, for example, an identifier of the UE's PDU session, QoS information for unicast services transmitted in the PDU session, and information about multicast / broadcast services.

[0293] S1405: The T-AMF receives a UE context creation request and sends a PDU session context update request (Nsmf_PDUSession_UpdateSMContext request) to the SMF based on the UE context creation request.

[0294] The PDU session context update request may include information about the UE's PDU session (e.g., identifier information of the UE's PDU session, QoS information of the unicast service transmitted in the PDU session, and information about the multicast / broadcast service (e.g., identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service)), identifier information of the T-AMF, a target ID, and N2 SM information carrying indirect forwarding tunnel information allocated by the S-gNB.

[0295] S1406: The SMF and UPF perform an N4 session update (N4 session modification).

[0296] For example, the SMF sends an N4 session update request to the UPF. Optionally, the N4 session update request carries indirect forwarding tunnel information allocated by the S-gNB. The UPF then returns an N4 session update response to the SMF. Optionally, the N4 session update response includes the indirect forwarding tunnel information allocated by the UPF, where the indirect forwarding tunnel allocated by the UPF is for establishing an indirect forwarding tunnel between the S-gNB and the T-gNB.

[0297] S1407: The SMF receives the PDU session context update request and sends a PDU session context update response (Nsmf_PDUSession_UpdateSMContext response) to the T-AMF.

[0298] The PDU session context update response may include information about the UE's PDU session, for example, identifier information of the UE's PDU session, QoS information of unicast services transmitted in the PDU session, and information about multicast / broadcast services (for example, identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service).

[0299] S1408: The T-AMF receives a PDU session context update response and sends a handover request to the T-gNB based on the PDU session context update response.

[0300] The handover request may include information about the UE's PDU session, for example, identifier information of the UE's PDU session, QoS information of the unicast service transmitted in the PDU session, and information about the multicast / broadcast service (for example, identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service).

[0301] S1409: The T-gNB receives a handover request and obtains PDU session information from the handover request. The T-gNB prepares / configures / allocates resources for / to the UE of a PDU session intended for transmitting data of the unicast service based on QoS information for the unicast service carried in the PDU session information. The T-gNB prepares / configures / allocates resources for / to the UE of a multicast / broadcast session intended for transmitting data of the multicast / broadcast service based on identifier information for the multicast / broadcast service and / or QoS information for the multicast / broadcast service carried in the PDU session information, and sends a handover request response (Handover Request ACK) to the S-gNB.

[0302] Specifically, for the execution process of S1409, please refer to the process of S1303 in Fig. 13. The details will not be described again.

[0303] The handover request response includes configuration information of a PDU session for transmitting data of a unicast service, and may include first configuration information. For a related description of the first configuration information, please refer to the description in S1202. Details will not be described again.

[0304] S1410: T-AMF sends a PDU session context update request to SMF.

[0305] The PDU session context update request (Nsmf_PDUSession_UpdateSMContext Request) may include information included in the handover request response in S1409, for example, configuration information of a PDU session for transmitting data of a unicast service and first configuration information.

[0306] S1411: The SMF sends a PDU session context update response to the T-AMF.

[0307] The PDU session context update response may include configuration information of a PDU session for transmitting data of a unicast service and first configuration information.

[0308] Optionally, the PDU session context update response further includes indirect forwarding tunnel information allocated by the UPF.

[0309] S1412: T-AMF sends a UE context generation response to S-AMF.

[0310] The UE context creation response (Nsmf_PDUSession_UpdateSMContext Response) may include configuration information of a PDU session for transmitting data of a unicast service and first configuration information.

[0311] S1413: The S-AMF sends a handover command to the S-gNB.

[0312] The handover command may include identifier information of the T-gNB, PDU session configuration information, and first configuration information.

[0313] S1414: The S-gNB sends a handover command to the UE.

[0314] S1415: The UE receives a handover command, and in response to the handover command, accesses the T-gNB based on identifier information of the T-gNB in the handover command, receives data of a unicast service transmitted in the PDU session based on configuration information of the PDU session carried in the handover command, and receives data of the multicast / broadcast service from the T-gNB based on first configuration information carried in the handover command by using the multicast / broadcast session.

[0315] S1416: T-gNB sends handover notification ication ) to T-AMF.

[0316] The handover notification may indicate that the UE has successfully handed over to the T-gNB.

[0317] S1417: T-AMF sends a PDU session context update request to SMF.

[0318] The PDU session context update request (Nsmf_PDUSession_UpdateSMContext) may carry identifier information of the PDU session tunnel allocated by the T-gNB. Optionally, the PDU session context update request may further carry information about an indirect forwarding tunnel generated by the T-gNB.

[0319] S1418: Perform N2 handover procedure.

[0320] For the N2 handover procedure, please refer to the description in 23.502 in the 3GPP standard. Details will not be described.

[0321] Based on the method shown in FIG. 14, in a 5G communication system, information about a multicast / broadcast service (e.g., identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service) is transmitted in advance to the T-gNB through interactions on the Xn interface between the S-gNB, the core network device, and the T-gNB, whereby the T-gNB pre-configures, for the terminal, resources of a multicast / broadcast session for transmitting data of the multicast / broadcast service. Therefore, as soon as possible after the terminal is handed over to the T-gNB, the terminal transmits data of the multicast / broadcast service by using the resources of the pre-configured multicast / broadcast session, thereby reducing interruption delay of the multicast / broadcast service.

[0322] Figures 13 and 14 are described by using an example in which a terminal is handed over between cells in a 5G communication system. With reference to the methods shown in Figures 15A and 15B or 16, and by using the 5G-4G interworking system shown in Figure 11b as an example, a multicast / broadcast service communication method when a terminal is handed over from a cell in a 5G network to a cell in a 4G network is described hereinafter. With reference to the methods shown in Figures 17A and 17B or 18A and 18B, a multicast / broadcast service communication method when a terminal is handed over from a cell in a 4G network to a cell in a 5G network is described.

[0323] 15A and 15B show a multicast / broadcast service communication method according to an embodiment of the present application. In this method, the source access network device is an NG-RAN and the target access network device is an E-UTRAN. As shown in FIG. 15A and 15B, the method may include the following steps:

[0324] S1500 to S1502a are performed in accordance with existing procedures for interworking from a 5G network to a 4G network.

[0325] S1500: Establish a multicast / broadcast session for a UE and a QF for a multicast / broadcast service in a 5G communication system.

[0326] For the execution process of S1500, please refer to the prior art. Details will not be described. In this case, the UE joins the multicast / broadcast service, and the PGW-C+SMF stores information about the multicast / broadcast service.

[0327] The relevant description of the information about the multicast / broadcast service is described in the embodiment corresponding to FIG. 12, and may include identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service.

[0328] S1501: When the NG-RAN decides to hand over the UE to the E-UTRAN, the NG-RAN sends a handover requirement to the AMF.

[0329] The NG-RAN may receive a measurement report from the UE and decide to hand over the UE to the E-UTRAN based on the measurement report. For specific execution processes, please refer to S1301 and S1302. Details will not be described again.

[0330] S1502a: The AMF receives the handover requirement and sends a PDU session context request (Nsmf_PDUSession_contextRequest) to the PGW-C+SMF.

[0331] S1502b: The PGW-C+SMF receives the PDU session context request and sends a PDU session context response to the AMF, carrying information about the multicast / broadcast service.

[0332] The PDU session context response (Nsmf_PDUSession_contextResponse) may include information about the multicast / broadcast service.

[0333] S1503: The NG-RAN receives the PDU session context response, obtains information about the multicast / broadcast service from the PDU session context response, and sends a relocation request carrying the information about the multicast / broadcast service to the MME.

[0334] S1504 and S1505: The MME sends a create session request to the SGW and receives a create session response returned by the SGW.

[0335] For the execution processes of S1504 and S1505, please refer to the existing procedures. Details will not be described here.

[0336] S1506: The MME sends the information about the multicast / broadcast service received in S1503 to the E-UTRAN through a handover request.

[0337] S1507: The E-UTRAN receives the handover request, and prepares / configures / allocates resources for / to the UE for a multicast / broadcast session intended for transmitting data of the multicast / broadcast service based on the identifier information of the multicast / broadcast service and / or the QoS information of the multicast / broadcast service carried in the handover request, and sends a handover request response (Handover Request ACK) carrying the first configuration information to the MME.

[0338] For the process in which E-UTRAN prepares / configures / allocates resources for a multicast / broadcast session for / to a UE based on the identifier information of the multicast / broadcast service and / or the QoS information of the multicast / broadcast service, please refer to the description in step 1201. The details will not be described again.

[0339] For the related description of the first setting information, please refer to the description in S1202. The details will not be described again.

[0340] S1508: The MME sends a create indirect data forwarding tunnel request to the SGW, and receives a create indirect data forwarding tunnel response from the SGW.

[0341] For the execution process of S1508, please refer to the existing procedure. Details will not be described.

[0342] S1509: The MME receives the handover request response and sends a relocation response carrying the first configuration information to the AMF.

[0343] Steps S1510a to S1510c are executed. For the execution process of steps S1510a to S1510c, please refer to the prior art. Details will not be described.

[0344] S1511a: The AMF receives a relocation response carrying the first configuration information and sends a handover command carrying the first configuration information to the NG-RAN.

[0345] S1511b: The NG-RAN receives the handover command and sends the handover command to the UE.

[0346] Further, the UE receives a handover command, and in response to the handover command, accesses the E-UTRAN and receives data of the multicast / broadcast service from the E-UTRAN by using the multicast / broadcast session and based on the first configuration information carried in the handover command.

[0347] 15A and 15B, in a 5G-4G interworking communication system, information about a multicast / broadcast service is transmitted in advance to a 4G base station through interaction between a 5G base station and a 5G core network device, whereby the 4G base station pre-configures, for a terminal, resources of a multicast / broadcast session for transmitting data of the multicast / broadcast service. Therefore, as soon as possible after the terminal is handed over from the 5G base station to the 4G base station, the terminal transmits the data of the multicast / broadcast service by using the resources of the pre-configured multicast / broadcast session, thereby reducing interruption delay of the multicast / broadcast service and improving transmission efficiency of data of the multicast / broadcast service.

[0348] 16 shows a multicast / broadcast service communication method according to an embodiment of the present application. In this method, the source access network device is an NG-RAN and the target access network device is an E-UTRAN. As shown in FIG. 16, this method may include the following steps:

[0349] S1600: Establish a multicast / broadcast session for a UE and a QF for a multicast / broadcast service in a 5G communication system.

[0350] For the execution process of S1600, please refer to the prior art. Details will not be described. In this case, the UE joins the multicast / broadcast service, and the PGW-C+SMF stores information about the multicast / broadcast service.

[0351] The relevant description of the information about the multicast / broadcast service is described in the embodiment corresponding to FIG. 12, and may include identifier information of the multicast / broadcast service and / or QoS information of the multicast / broadcast service.

[0352] S1601: When the NG-RAN decides to handover the UE to the E-UTRAN, the NG-RAN sends a message 1 carrying information about the multicast / broadcast service to the E-UTRAN.

[0353] The NG-RAN may receive a measurement report from the UE and decide to hand over the UE to the E-UTRAN based on the measurement report. For specific execution processes, please refer to S1301 and S1302. Details will not be described again.

[0354] S1602: The E-UTRAN receives a message 1 carrying information about a multicast / broadcast service, and prepares / configures / allocates resources for / to the UE for a multicast / broadcast session intended for transmitting data of the multicast / broadcast service based on the information about the multicast / broadcast service, and sends a message 2 carrying first configuration information to the NG-RAN.

[0355] For the process in which E-UTRAN prepares / configures / allocates resources for a multicast / broadcast session for / to a UE based on information about the multicast / broadcast service, please refer to the description in step 1201. The details will not be described again.

[0356] For the related description of the first setting information, please refer to the description in S1202. The details will not be described again.

[0357] S1603: The NG-RAN receives a message 2 carrying the first configuration information, and sends the first configuration information to the UE.

[0358] Furthermore, the NG-RAN may send E-UTRAN identifier information to the UE. After receiving the first configuration information, the UE accesses the E-UTRAN based on the E-UTRAN identifier information, and then receives data of the multicast / broadcast service from the E-UTRAN by using the multicast / broadcast session and based on the first configuration information.

[0359] 16, in a 5G-4G interworking communication system, a 5G base station directly transmits information about a multicast / broadcast service to a 4G base station in advance, so that the 4G base station pre-configures multicast / broadcast session resources for transmitting data of the multicast / broadcast service for the UE. Therefore, as soon as possible after the terminal is handed over from the 5G base station to the 4G base station, the UE transmits the data of the multicast / broadcast service by using the pre-configured multicast / broadcast session resources, thereby reducing interruption delay of the multicast / broadcast service and improving transmission efficiency of data of the multicast / broadcast service.

[0360] Referring to the communication network shown in Figure 11b, assuming that the terminal is a UE, the source access network device is E-UTRAN, the target access network device is NG-RAN, the source mobility management network element is MME, and the target mobility management network element is AMF, the following describes a service handover process in which the terminal is handed over from a source access network device in a 4G network to a target access network device in a 5G network.

[0361] 17A and 17B are flowcharts of a multicast / broadcast service communication method according to an embodiment of the present application. As shown in FIG. 17A and 17B, the method may include the following steps:

[0362] S1701: The UE sends a measurement report to the E-UTRAN.

[0363] The UE is a UE that joins a multicast / broadcast group corresponding to a multicast / broadcast service.

[0364] The measurement report may include identifier information of the multicast / broadcast service. For the related description of the measurement report and the execution process of S1701, please refer to the description in S1301. The details will not be described again.

[0365] It should be noted that the identifier information included in the measurement report for a multicast / broadcast service may alternatively be replaced with other identifier information indicating that the UE is joining a multicast / broadcast group, for example, it may alternatively be replaced with interest indication information for a multicast / broadcast service (e.g., MBMS interest indication).

[0366] S1702: The E-UTRAN receives the measurement report, and determines to hand over the terminal to the target base station NG-RAN based on the measurement report, and determines a handover requirement ment ) to the MME.

[0367] The handover requirement may be for requesting handover of the UE to a cell corresponding to the NG-RAN. The handover requirement may include multicast / broadcast service identifier information and other existing information, such as NG-RAN identifier information, direct forwarding path availability, and target tracking area identifier. The NG-RAN identifier information uniquely identifies the NG-RAN. The direct forwarding path availability may indicate whether direct forwarding from a source access network device to a target access network device is available. The target tracking area identifier may be used by the MME to select an AMF.

[0368] For example, the E-UTRAN's decision to hand over the terminal to the target base station based on the measurement report may include the E-UTRAN selecting, based on the measurement report, an access network device corresponding to a cell having the greatest measured value of signal quality from the signal quality measurements of one or more cells, as the target access network device NG-RAN. Alternatively, when the UE joins a multicast / broadcast group, the E-UTRAN selects, from the signal quality measurements of one or more cells, an access network device that supports the multicast / broadcast group and has the highest signal quality, as the target access network device NG-RAN.

[0369] Furthermore, when the target access network device determined by the E-UTRAN is not the access network device E-UTRAN currently accessed by the UE, the E-UTRAN sends information such as NG-RAN identifier information, availability of a direct forwarding path, and target tracking area identifier to the MME through the handover requirement.

[0370] S1703: The MME receives a handover requirement and sends a forwarding relocation request to the AMF based on the handover requirement.

[0371] The forward relocation request may be for requesting the AMF to perform mobility management for the UE. The forward relocation request may carry identifier information of the multicast / broadcast service.

[0372] For the relevant description of the first setting information, please refer to the above description, and the details will not be described again.

[0373] For example, the MME may send a forward relocation request to the AMF based on an identifier of the target tracking area carried in the handover requirement. Alternatively, the MME may determine the NG-RAN based on identifier information of the NG-RAN carried in the handover requirement, and send a forward relocation request to the AMF that manages the NG-RAN.

[0374] S1704: The AMF receives a forwarding relocation request and sends a PDU session context creation request to the PGW-C+SMF.

[0375] The Create PDU Session Context Request (Nsmf_PDU session_create SMContext request) may notify the PGW-C+SMF to prepare to establish PDU session resources, a forwarding tunnel, etc. for the UE. In addition to the existing information elements specified in 3GPP Technical Specification 23502, the Create PDU Session Context Request further includes identifier information belonging to a multicast / broadcast service, indicating that the UE will join a multicast / broadcast group.

[0376] S1705: When the PCF sets a dynamic PCC rule, after the PGW-C+SMF receives the PDU session context creation request, the PGW-C+SMF sends a session policy association update (the SMF initiated the SM policy modification) to the PCF, and the PCF receives the session policy association update and sends the PCC rule to the PGW-C+SMF.

[0377] PCC rules consist of service data flow (SDF) identification rules for unicast services and packet filtering rules for unicast services. ingWhen the Create PDU Session Context Request carries identifier information of a multicast / broadcast service, the PCC rule sent by the PCF to the PGW-C+SMF may further include an SDF identification rule of the multicast / broadcast service and packet filtering information of the multicast / broadcast service.

[0378] In addition, the PCC rule may include other configuration parameters for transmitting data to be transmitted to the UE, such as a PDR, a forwarding action rule (FAR) associated with the PDR, a QoS requirement, or a QF mapping rule. For a related description of the configuration parameters, please refer to the prior art.

[0379] It should be understood that S1705 is a session management policy update process initiated by the SMF. When the dynamic PCC rule is not set by the PCF and the PCC rule is statically set, S1705 is skipped.

[0380] S1706: The PGW-C+SMF sends an N4 session modification request to the PGW-U+UPF. In response, the PGW-U+UPF receives the N4 session modification request and sends an N4 session modification response to the PGW-C+SMF. The N4 session modification is now completed.

[0381] The N4 session modification request may be for establishing a PDU session. The N4 session modification request may carry information such as PDR, FAR, and QER. Furthermore, when the PGW-C+SMF assigns tunnel information of the PDU session to the PGW-U+UPF (this may be referred to as tunnel information of the PGW-U+UPF for short), the N4 session establishment request may further carry tunnel information of the PGW-U+UPF. The tunnel information of the PGW-U+UPF may include an IP address and / or a port number of the PGW-U+UPF.

[0382] S1707: After the N4 session modification is completed, the PGW-C+SMF sends a PDU session context creation response to the AMF.

[0383] The PDU session context creation response (Nsmf_PDUSession_CreateSMContext Response) may include identifier information and N2 SM information of a PDU session corresponding to a unicast service, identifier information of a multicast / broadcast service, N2 SM information corresponding to a multicast / broadcast service, etc.

[0384] The N2 SM information of a unicast service may include a QFI of the unicast service, QoS parameters corresponding to the QFI of the unicast service (e.g., parameters such as 5QI, ARP, QoS notification control (QNC), MBR, or GBR corresponding to the QFI), and a mapping relationship between an EPS bearer identifier (EBI) and the QFI. The N2 SM information corresponding to a multicast / broadcast service may include a QFI of the multicast / broadcast service and QoS parameters corresponding to the QFI of the multicast / broadcast service (e.g., parameters such as 5QI, ARP, QoS notification control (QNC), MBR, or GBR corresponding to the QFI).

[0385] S1708: The AMF receives a PDU session context generation request and sends a handover request to the NG-RAN.

[0386] The handover request may be for requesting handover of the UE to the NG-RAN. The handover request may include N2 SM information corresponding to the unicast service in S1707. When the UE joins a multicast / broadcast group, the handover request further includes N2 SM information corresponding to the multicast / broadcast service.

[0387] S1709: The NG-RAN receives a handover request carrying N2 SM information, and allocates resources of a PDU session between the NG-RAN and the UE, which is for transmitting data of the unicast service, to the UE based on the N2 SM information corresponding to the unicast service.

[0388] When the handover request carries N2 SM information corresponding to the multicast / broadcast service and the multicast / broadcast service has not been started, for example, when there are no air interface resources and / or context information configured for the multicast / broadcast service in the NG-RAN, the NG-RAN allocates resources for a multicast / broadcast session to the UE, which is intended for transmitting data of the multicast / broadcast service, based on the N2 SM information corresponding to the multicast / broadcast service. The NG-RAN sends a handover request response (Handover Request ACK) to the AMF.

[0389] The handover request response may carry PDU session configuration information and first configuration information. For related descriptions of the PDU session configuration information and the first configuration information, please refer to the description in S1303. Details will not be described again.

[0390] Additionally, the handover request response may further carry tunnel information corresponding to the PDU session allocated by the NG-RAN.

[0391] S1710: The AMF receives the handover request response and sends a PDU session context update request to the PGW-C+SMF.

[0392] The PDU session context update request (Nsmf_PDUSession_UpdateSMContext Request) carries tunnel information allocated by the NG-RAN for the PDU session and configuration information for the PDU session, and may further carry tunnel information allocated by the NG-RAN for the multicast / broadcast session and first configuration information at S1709.

[0393] S1711: The PGW-C+SMF receives a PDU session context update request and performs N4 session modification together with the PGW-U+UPF based on the PDU session context update request.

[0394] For example, the PGW-C+SMF sends an N4 session modification request to the PGW-U+SMF, where the N4 session modification request may carry tunnel information allocated by the NG-RAN for the PDU session and tunnel information allocated by the NG-RAN for the multicast / broadcast session. The PGW-U+UPF receives the N4 session modification request, stores a correspondence between the tunnel information of the PDU session and the QFI of the unicast service, establishes a transmission tunnel for the PDU session between the NG-RAN and the PGW-U+UPF, stores a correspondence between the tunnel information of the multicast / broadcast session and the QFI of the multicast / broadcast service, and establishes a transmission tunnel for the multicast / broadcast session between the NG-RAN and the PGW-U+UPF.

[0395] Furthermore, when a transmission tunnel between the MB-UPF and the PGW-U+UPF for transmitting data of a multicast / broadcast service is not established, steps S1712 to S1714 and steps S1715 to S1719 are executed. Conversely, when a transmission tunnel between the MB-UPF and the PGW-U+UPF for transmitting data of a multicast / broadcast service is established, steps S1712 to S1714 are skipped and steps S1715 to S1719 are executed without steps S1712 to S1714.

[0396] S1712: PGW-C+SMF transmits message 001 to MB-SMF.

[0397] Message 001 is to inform the MB-SMF that the UE expects or should be handed over to the NG-RAN.

[0398] Optionally, when a transmission tunnel between the MB-UPF and the PGW-U+UPF for transmitting data of the multicast / broadcast service has not been established, the PGW-C+SMF may instead notify the MB-SMF to establish a transmission tunnel between the MB-UPF and the PGW-U+UPF for transmitting data of the multicast / broadcast service. In this case, message 001 may carry downlink tunnel information belonging to the PGW-U+UPF, which is allocated to the PGW-U+UPF by the PGW-C+SMF.

[0399] S1713: MB-SMF receives message 001 and sends N4 session modification to MB-UPF based on message 001.

[0400] Specifically, the process may include the MB-SMF sending the received downlink tunnel information, which is allocated by the PGW-C+SMF and belongs to the PGW-U+UPF, and the tunnel information allocated to the MB-UPF by the MB-SMF to the MB-UPF, the MB-UPF storing a correspondence between the tunnel information of the PGW-U+UPF and the tunnel information allocated to the MB-UPF by the MB-SMF, and establishing a transmission tunnel between the MB-UPF and the PGW-U+UPF for transmitting data of the multicast / broadcast service.

[0401] S1714: In response to message 001, MB-SMF sends message 002 to PGW-U+SMF.

[0402] In response, the PGW-U+SMF receives message 002.

[0403] So far, a transmission tunnel between the MB-UPF and the PGW-U+UPF, and a transmission tunnel between the PGW-U+UPF and the NG-RAN have been established for transmitting data for multicast / broadcast services.

[0404] S1715: In response to S1710, the PGW-C+SMF sends a PDU session context update response to the AMF.

[0405] The PDU session context update response (Nsmf_PDUSession_UpdateSMContext Response) may carry configuration information of the PDU session and first configuration information.

[0406] S1716: The AMF receives the PDU session context update response and sends a forward relocation response to the MME.

[0407] In addition to the existing information elements specified in 3GPP Technical Specification 23502, the forward relocation response further includes PDU session configuration information and first configuration information.

[0408] S1717: The MME receives the forward relocation response and sends a handover command to the E-UTRAN.

[0409] The handover command may include PDU session configuration information and first configuration information.

[0410] S1718: The E-UTRAN receives the handover command and sends the handover command to the UE.

[0411] S1719: The UE receives a handover command, hands over to the NG-RAN based on the handover command, establishes communication with the NG-RAN, receives data of a unicast service transmitted on the PDU session based on configuration information of the PDU session, and receives data of a multicast / broadcast service from the NG-RAN by using the multicast / broadcast session and based on the first configuration information carried in the handover command.

[0412] Based on the methods shown in Figures 17A and 17B, before a UE participating in a multicast / broadcast service is handed over to a 5G communication system, resources of a multicast / broadcast session corresponding to the multicast / broadcast service may be configured in advance for the UE, and first configuration information corresponding to the resources of the multicast / broadcast session is sent to the UE before the UE is handed over, so that the UE immediately receives data of the multicast / broadcast service based on the first configuration information after the handover, thereby reducing the interruption delay of the multicast / broadcast service when the UE moves across systems from E-UTRAN / EPC to NR / 5GC and improving the transmission efficiency of the multicast / broadcast service.

[0413] Referring to the communication network shown in Figure 11b, assuming that the terminal is a UE, the source access network device is E-UTRAN, the target access network device is NG-RAN, the source mobility management network element is MME, and the target mobility management network element is AMF, the following describes a service handover process in the manner shown in Figure 12, in which the terminal is handed over from a source access network device in a 4G network to a target access network device in a 5G network.

[0414] 17A and 17B, in the embodiment shown in Figures 18A and 18B, before a handover process is performed, the PGW-C+SMF is triggered to establish a transmission channel between the MB-UPF and the PGW-U+UPF, and the PGW-C+SMF is triggered to configure N2 SM information for a unicast service and for a multicast / broadcast service, and to send the N2 SM information corresponding to the unicast service and the N2 SM information corresponding to the multicast / broadcast service to the NG-RAN. Subsequently, in the handover process, the NG-RAN configures PDU session resources based on the N2 SM information corresponding to the unicast service and configures multicast / broadcast session resources based on the N2 SM information corresponding to the multicast / broadcast service, and transmits the PDU session configuration information and first configuration information to the UE via the MME and the E-UTRAN, so that the UE receives data of the unicast service based on the PDU session configuration information and receives data of the multicast / broadcast service based on the first configuration information. Specifically, for this process, please refer to the embodiment corresponding to the method shown in Figures 18A and 18B.

[0415] 18A and 18B are flowcharts of a multicast / broadcast service communication method according to an embodiment of the present application. The method includes the following steps:

[0416] S1801: The UE sends a measurement report to the E-UTRAN.

[0417] For the related description of the measurement report and the execution process of S1801, please refer to the description in S1301. The details will not be described again.

[0418] The UE is a UE that joins a multicast / broadcast group corresponding to a multicast / broadcast service.

[0419] The measurement report may include identifier information of the multicast / broadcast service. For the related description of the measurement report and the execution process of S1701, please refer to the description in S1301. The details will not be described again.

[0420] It should be noted that the identifier information included in the measurement report for the multicast / broadcast service may alternatively be replaced with other identifier information indicating that the UE is joining a multicast / broadcast group, for example, it may alternatively be replaced with interest indication information for the multicast / broadcast service (e.g., MBMS interest indication).

[0421] S1802: The E-UTRAN receives the measurement report, and determines to hand over the terminal to the NG-RAN based on the measurement report, and sends identifier information of the multicast / broadcast service to the NG-RAN.

[0422] For the process in which the E-UTRAN decides to hand over the terminal to the NG-RAN based on the measurement report, please refer to the description in S1702 of Figures 17A and 17B, and the details will not be described again.

[0423] S1803: The NG-RAN receives identifier information of the multicast / broadcast service and transmits the identifier information of the multicast / broadcast service to the AMF.

[0424] S1804: The AMF receives the identifier information of the multicast / broadcast service and sends a PDU session context update request carrying the identifier information of the multicast / broadcast service to the PGW-C+SMF.

[0425] S1805: The PGW-C+SMF receives a PDU session context update request carrying identifier information of the multicast / broadcast service, and sends a message 001 to the MB-SMF based on the PDU session context update request.

[0426] Message 001 is to inform the MB-SMF that the UE expects or should be handed over to the NG-RAN. Message 001 may carry identifier information for multicast / broadcast services.

[0427] Optionally, when a transmission tunnel between the MB-UPF and the PGW-U+UPF for transmitting data of the multicast / broadcast service has not been established, the PGW-C+SMF may instead notify the MB-SMF to establish a transmission tunnel between the MB-UPF and the PGW-U+UPF for transmitting data of the multicast / broadcast service. In this case, message 001 may further carry downlink tunnel information belonging to the PGW-U+UPF, which is allocated to the PGW-U+UPF by the PGW-C+SMF.

[0428] S1806: MB-SMF receives message 001 and sends an N4 session modification to MB-UPF.

[0429] The specific processing of S1806 may be that the MB-SMF sends the received downlink tunnel information belonging to the PGW-U+UPF, allocated by the PGW-C+SMF, and the tunnel information allocated to the MB-UPF by the MB-SMF to the MB-UPF. The MB-UPF stores the correspondence between the tunnel information of the PGW-U+UPF and the tunnel information allocated to the MB-UPF by the MB-SMF, and establishes a transmission tunnel between the MB-UPF and the PGW-U+UPF, which is for transmitting data of the multicast / broadcast service.

[0430] S1807: In response to message 001, MB-SMF transmits message 002 to PGW-U+SMF.

[0431] Message 002 may carry identifier information of the multicast / broadcast session, N2 SM information corresponding to the multicast / broadcast service, etc. For example, the MB-SMF may obtain N2 SM information corresponding to the multicast / broadcast service from the MB-PCF based on the identifier information of the multicast / broadcast service carried in message 001, and send the obtained N2 SM information corresponding to the multicast / broadcast service to the PGW-U+SMF through message 002.

[0432] So far, a transmission tunnel from MB-UPF to PGW-U+UPF has been established, which is intended to transmit data of multicast / broadcast services.

[0433] S1808: PGW-U+SMF receives message 002 and sends a PDU session context update response to AMF.

[0434] The PDU session context update response may include identifier information and N2 SM information of a PDU session corresponding to a unicast service, identifier information of a multicast / broadcast session, N2 SM information corresponding to a multicast / broadcast service, etc.

[0435] For the related description of N2 SM information corresponding to unicast service and N2 SM information corresponding to multicast / broadcast service, please refer to the description in S1707, and the details will not be described again.

[0436] Furthermore, the PDU session context update response may include tunnel information of the PGW-U+UPF.

[0437] S1809: The AMF receives the PDU session context update response and sends N2 SM information to the NG-RAN. In response, the NG-RAN receives the N2 SM information.

[0438] S1810: The E-UTRAN sends a handover requirement to the MME based on the measurement report.

[0439] S1811: The MME receives a handover requirement and sends a forwarding relocation request to the AMF based on the handover requirement.

[0440] S1812: The AMF receives a forwarding relocation request and sends a PDU session context creation request to the PGW-C+SMF.

[0441] S1813: When the PCF configures a dynamic PCC rule, after the PGW-C+SMF receives the PDU session context creation request, the PGW-C+SMF sends a session policy association update (SMF initiated SM policy modification) to the PCF, and the PCF receives the session policy association update, sends the PCC rule to the PGW-C+SMF, and performs the session policy update process.

[0442] S1814: The PGW-C+SMF sends an N4 session modification to the PGW-U+UPF.

[0443] S1815: After the N4 session modification is completed, the PGW-C+SMF sends a PDU session context creation response to the AMF.

[0444] S1816: The AMF receives a PDU session context generation request and sends a handover request to the NG-RAN.

[0445] S1817: The NG-RAN receives the handover request, and allocates, to the UE, resources of a PDU session between the NG-RAN and the UE for transmitting data of the unicast service based on the N2 SM information corresponding to the unicast service received in S1809, and allocates, to the UE, resources of a PDU session between the NG-RAN and the UE for transmitting data of the multicast / broadcast service based on the N2 SM information corresponding to the multicast / broadcast service received in S1809. The NG-RAN sends a handover request response (handover request ACK) to the AMF. The handover request response carries configuration information of the PDU session and the first configuration information.

[0446] S1818: The AMF receives the handover request response and sends a PDU session context update request to the PGW-C+SMF, carrying the PDU session configuration information and the first configuration information.

[0447] S1819: The PGW-C+SMF receives the PDU session context update request and sends an N4 session modification request to the PGW-U+UPF. In response, the PGW-U+UPF receives the N4 session modification request and sends an N4 session modification response to the PGW-C+SMF. The N4 session modification is now completed.

[0448] The N4 session modification request may be for establishing a PDU session. The N4 session modification request may carry information such as a PDR, a FAR, and a QER. Furthermore, when the PGW-C+SMF allocates tunnel information of the PDU session to the PGW-U+UPF (which may be referred to as tunnel information of the PGW-U+UPF for short), the N4 session establishment request may further carry tunnel information of the PGW-U+UPF. The tunnel information of the PGW-U+UPF may include an IP address and / or a port number of the PGW-U+UPF.

[0449] S1820: The PGW-C+SMF sends a PDU session context update response to the AMF, carrying the PDU session configuration information and the first configuration information.

[0450] S1821: The AMF receives a PDU session context update response from the PGW-C+SMF and sends a forwarding relocation response to the MME, carrying the PDU session configuration information and the first configuration information.

[0451] S1822: The MME receives the forwarding relocation response and sends a handover command to the E-UTRAN, carrying the PDU session configuration information and the first configuration information.

[0452] S1823: The E-UTRAN receives the handover command and sends the handover command, carrying the PDU session configuration information and the first configuration information, to the UE.

[0453] Further, the UE receives a handover command, hands over to the NG-RAN based on the handover command, establishes communication with the NG-RAN, receives data of a unicast service transmitted on the PDU session based on the configuration information of the PDU session, and receives data of a multicast / broadcast service from the NG-RAN by using the multicast / broadcast session and based on the first configuration information carried in the handover command.

[0454] Based on the methods shown in Figures 18A and 18B, before a UE participating in a multicast / broadcast service is handed over to a 5G communication system, resources of a multicast / broadcast session corresponding to the multicast / broadcast service may be configured in advance for the UE, and first configuration information corresponding to the resources of the multicast / broadcast session is sent to the UE before the UE is handed over, thereby reducing the interruption delay of the multicast / broadcast service and improving the transmission efficiency of the multicast / broadcast service when the UE moves across systems from E-UTRAN / EPC to NR / 5GC.

[0455] The foregoing mainly describes the solutions provided in the embodiments of the present application from the perspective of interactions between nodes. It can be understood that, to implement the above-described functions, each node, for example, a first session management function network element or an application server, includes a corresponding hardware structure and / or software module for implementing each function. Those skilled in the art will readily recognize that the algorithm steps in the examples described with reference to the embodiments disclosed herein can be implemented in the form of hardware, software, or a combination of hardware and computer software in the methods of the embodiments of the present application. Whether a function is performed by hardware or hardware driven by computer software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0456] In the embodiment of the present application, the first session management function network element or the application server may be divided into functional modules based on the above-mentioned method examples. For example, each functional module may be obtained through division based on each corresponding function, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware or in the form of a software functional module. It should be noted that in the embodiment of the present application, the module division is an example and is merely a logical functional division. In actual implementation, other division styles may be used.

[0457] 19 is a diagram of the structure of a communication device 190. The communication device 190 may be a source access network device, a chip or system-on-chip within the source access network device, another device capable of implementing the functions of the source access network device in the aforementioned method, etc. The communication device 190 may be configured to perform the functions of the source access network device in the aforementioned method embodiments. In a possible implementation, the communication device 190 shown in FIG. 19 includes a processing unit 1901 and a transceiver unit 1902.

[0458] The processing unit 1901 is configured to control the transceiver unit 1902 to obtain first configuration information, which is used by the terminal to receive data belonging to a multicast / broadcast service transmitted on a multicast / broadcast session after the terminal is handed over to the target access network device.

[0459] The processing unit 1901 is further configured to control the transceiver unit 1902 to send the first configuration information to the terminal.

[0460] Specifically, all relevant contents of the steps in the above-mentioned method embodiments shown in Figures 12 to 18A and 18B can be cited in the functional descriptions of the corresponding functional modules. The details will not be described again in this specification. The communication device 190 is configured to perform the functions of the source access network device in the multicast / broadcast service communication method shown in Figures 12 to 18A and 18B, and to achieve the same effects as the multicast / broadcast service communication method.

[0461] In another implementation, the communication device 190 shown in FIG. 19 includes a processing module and a communication module. The processing module is configured to control and manage actions of the communication device 190. For example, the processing module may integrate the functions of the processing unit 1901 and may be configured to support the communication device 190 in performing steps such as S1203. The communication module may integrate the functions of the transceiver unit 1902 and communicate with another network entity, for example, with a functional module or network entity shown in any of the communication systems in FIGS. 10 to 11b. Furthermore, the communication device 190 may further include a storage module configured to store instructions and / or data. When the instructions are executed by the processing module, the processing module is enabled to implement the method at the source access network device.

[0462] The processing module may be a processor, a controller, a module, or a circuit. The processing module may implement or execute various exemplary logic blocks described with reference to the contents disclosed in the embodiments of the present application. The communication module may be a transceiver circuit, a pin, an interface circuit, a bus interface, a communication interface, etc. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication device 190 in this embodiment of the present application may be the communication device shown in FIG. 4.

[0463] 20 is a diagram of the structure of a communication device 200. The communication device 200 may be a target access network device, a chip or system-on-chip in the target access network device, another device capable of implementing the functions of the target access network device in the above-mentioned method, etc. The communication device 200 may be configured to perform the functions of the target access network device in the above-mentioned method embodiments. In a possible implementation, the communication device 200 shown in FIG. 20 includes a processing unit 2001 and a transmitting unit 2002.

[0464] The processing unit 2001 is configured to allocate resources of a multicast / broadcast session to the terminals, the multicast / broadcast session being for transmitting data of a multicast / broadcast service.

[0465] The sending unit 2002 is configured to send first configuration information, the first configuration information representing resources of a multicast / broadcast session, the first configuration information being used by the terminal to receive data belonging to a multicast / broadcast service transmitted on the multicast / broadcast session after the terminal is handed over to the target access network device.

[0466] Specifically, all relevant contents of the steps in the above-mentioned method embodiments shown in Figures 12 to 18A and 18B can be cited in the functional descriptions of the corresponding functional modules. The details will not be described again in this specification. The communication device 200 is configured to perform the functions of the target access network device in the multicast / broadcast service communication method shown in Figure 12 and Figures 18A and 18B. Therefore, the same effects as those of the multicast / broadcast service communication method can be achieved.

[0467] In another implementation, the communication device 200 shown in FIG. 20 includes a processing module and a communication module. The processing module is configured to control and manage actions of the communication device 200. For example, the processing module may integrate the functions of the processing unit 2001 and may be configured to support the communication device 200 in performing steps such as S1201. The communication module may integrate the functions of the sending unit 2002 and communicate with another network entity, for example, with a functional module or network entity shown in any of the communication systems in FIGS. 2 and 3. Furthermore, the communication device 200 may further include a storage module configured to store instructions and / or data. When the instructions are executed by the processing module, the processing module is enabled to implement the method at the target access network device.

[0468] The processing module may be a processor, a controller, a module, or a circuit. The processing module may implement or execute various exemplary logic blocks described with reference to the contents disclosed in the embodiments of the present application. The communication module may be a transceiver circuit, a pin, an interface circuit, a bus interface, a communication interface, etc. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication device 200 in this embodiment of the present application may be the communication device shown in FIG. 4.

[0469] 21 is a diagram of the structure of a communication device 210. The communication device 210 may be a terminal, a chip or system-on-chip in a terminal, another device capable of implementing the functions of the terminal in the above-described method, etc. The communication device 210 may be configured to perform the functions of the terminal in the above-described method embodiments. In a possible implementation, the communication device 210 shown in FIG. 21 includes a receiving unit 2101 and a processing unit 2102.

[0470] The receiving unit 2101 is configured to receive first configuration information from a source access network device, where the first configuration information represents resources of a multicast / broadcast session, and the first configuration information is used by the terminal to receive data belonging to a multicast / broadcast service transmitted on the multicast / broadcast session after the terminal is handed over to the target access network device.

[0471] The processing unit 2102 is configured to receive data belonging to a multicast / broadcast service coming from the target access network device by using the multicast / broadcast session and based on the first configuration information.

[0472] Specifically, all relevant contents of the steps in the above-described method embodiments shown in Figures 12 to 18A and 18B can be cited in the functional descriptions of the corresponding functional modules. The details will not be described again in this specification. The communication device 210 is configured to perform the functions of the terminal in the multicast / broadcast service communication method shown in Figure 12 and Figures 18A and 18B. Therefore, the same effects as those of the above-described multicast / broadcast service communication method can be achieved.

[0473] In another implementation, the communication device 210 shown in FIG. 21 includes a processing module and a communication module. The processing module is configured to control and manage actions of the communication device 210. For example, the processing module may be configured to integrate the functions of the processing unit 2102 and support the communication device 210 in performing steps such as S1205. The communication module may integrate the functions of the transmitting unit 2101 and communicate with another network entity, for example, with a functional module or network entity shown in any of the communication systems in FIGS. 2 and 3. Furthermore, the communication device 210 may further include a storage module configured to store instructions and / or data. When the instructions are executed by the processing module, the processing module is enabled to implement the method at the terminal side.

[0474] The processing module may be a processor, a controller, a module, or a circuit. The processing module may implement or execute various exemplary logic blocks described with reference to the contents disclosed in the embodiments of the present application. The communication module may be a transceiver circuit, a pin, an interface circuit, a bus interface, a communication interface, etc. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication device 210 in this embodiment of the present application may be the communication device shown in FIG. 4.

[0475] Figure 22 is a diagram of the structure of a communication system according to an embodiment of the present application. As shown in Figure 22, the communication system may include a source access network device 220, a target access network device 221, and a terminal 222. It should be noted that Figure 22 is only an example of the accompanying drawings. The network elements and the number of network elements included in the communication system shown in Figure 22 are not limited in this embodiment of the present application.

[0476] The source access network device 220 has the function of the source access network device in any one of the methods in Figures 12 to 18A and 18B. The target access network device 221 has the function of the target access network device in any one of the methods in Figures 12 to 18A and 18B. The terminal 222 has the function of the terminal in any one of the methods in Figures 12 to 18A and 18B.

[0477] An embodiment of the present application further provides a computer-readable storage medium. All or some of the processes in the aforementioned method embodiments may be implemented by a computer program that instructs associated hardware. The program may be stored in a computer-readable storage medium. When the program is executed, the processes in the aforementioned method embodiments may be included. The computer-readable storage medium may be, for example, an internal storage unit of a terminal device according to any one of the aforementioned embodiments, including a data sender and / or a data receiver. For example, the computer-readable storage medium may be a hard disk or memory of the terminal device. Alternatively, the computer-readable storage medium may be an external storage device of the terminal device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, or a flash card configured for the terminal device. The computer-readable storage medium may include both the internal storage unit and the external storage device of the terminal device. The computer-readable storage medium is configured to store computer programs and other programs and data required by the terminal device. The computer-readable storage medium may further be configured to temporarily store the outputted data or the data to be outputted.

[0478] The embodiments of the present application further provide computer instructions. All or some of the procedures in the above-mentioned method embodiments can be implemented by computer instructions that instruct related hardware (such as computers, processors, network devices, and terminals). The program can be stored in the above-mentioned computer-readable storage medium.

[0479] In the embodiments of the present application, " / " may represent an "or" relationship between associated objects. For example, A / B may represent A or B. "And / or" may indicate three relationships between associated objects. For example, A and / or B may represent three cases: only A exists, both A and B exist, and only B exists. A and B may be singular or plural. To facilitate the description of the technical solutions in the embodiments of the present application, terms such as "first" and "second" may be used in the embodiments of the present application to distinguish between technical features having the same or similar functions. Terms such as "first" and "second" do not limit the quantity and execution sequence, and terms such as "first" and "second" do not indicate a clear distinction. In the embodiments of the present application, terms such as "example" or "for example" are used to represent an example, illustration, or description. Any embodiment or design scheme described using "an example" or "for example" should not be interpreted as preferred or having more advantages over another embodiment or design scheme. Use of terms such as "an example" or "for example" is intended to present relevant concepts in a concrete manner for ease of understanding.

[0480] In the embodiments of this application, "first", "second", "third", "A", "B", "C", "D", etc. are used to distinguish between the technical features described by them. There is no chronological or dimensional order between the technical features described by "first", "second", "third", "A", "B", "C", and "D".

[0481] In the embodiments of the present application, it should be understood that "B corresponding to A" indicates that B is associated with A. For example, B may be determined based on A. It should be further understood that determining B based on A does not mean that B is determined based only on A. B may alternatively be determined based on A and / or other information. Also, in the embodiments of the present application, "connection" refers to various connection methods, such as a direct connection or an indirect connection for implementing communication between devices, which is not limited in the embodiments of the present application.

[0482] In the embodiments of the present application, unless otherwise specified, "transmit" refers to bidirectional transmission and includes a sending action and / or a receiving action. Specifically, "transmission" in the embodiments of the present application includes data transmission, data reception, or data transmission and data reception. In other words, data transmission in this specification includes uplink data transmission and / or downlink data transmission. Data may include channels and / or signals. Uplink data transmission is uplink channel transmission and / or uplink signal transmission, and downlink data transmission is downlink channel transmission and / or downlink signal transmission. In the embodiments of the present application, "network" and "system" represent the same concept, and a communication system is a communication network.

[0483] The division into modules in the embodiments of the present application is merely an example and is a division into logical functions, and other divisions may be used in actual implementation. Furthermore, the functional modules in the embodiments of the present application may be integrated into a single processor, or each module may exist physically independently, or two or more modules may be integrated into a single module. The integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0484] All or part of the technical solutions provided in the embodiments of the present application may be implemented by using software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, 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 program instructions are loaded and executed on a computer, procedures or functions according to the embodiments of the present invention are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a wireless controller, a network device, a terminal, or another programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired (e.g., coaxial cable, fiber optic, or digital subscriber line (DSL)) manner or wireless (e.g., infrared, radio, or microwave) manner. The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device, such as a server or data center, that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, or magnetic tapes), optical media (e.g., digital video discs (DVDs)), semiconductor media, etc.

[0485] In the embodiments of the present application, when there is no logical contradiction, the embodiments may be referenced to each other. For example, the terms in the method and / or method embodiments may be referenced to each other, and the terms in the function and / or device embodiments may be referenced to each other. For example, the functions and / or terms between the device embodiment and the method embodiment may be referenced to each other.

[0486] The above description is merely a specific implementation of the embodiments of the present application and is not intended to limit the protection scope of the embodiments of the present application. Any variation or substitution within the technical scope disclosed in the embodiments of the present application should fall within the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application should be subject to the protection scope of the claims.

Claims

1. A multicast / broadcast service communication method, comprising: determining, by a first network element, a Quality of Service Flow Identifier (QFI) for the multicast / broadcast service; transmitting, by the first network element, the QFI to at least two Session Management Function network elements; The at least two session management function network elements include a first session management function network element and a second session management function network element, and the method includes: receiving, by the first Session Management Function network element, the QFI; sending, by the first session management function network element, the QFI and a first quality of service profile (QoS profile) to a first access network device based on the QFI; receiving, by the second Session Management Function network element, the QFI; and transmitting, by the second session management function network element, the QFI and a second QoS profile to a second access network device based on the QFI; the second QoS profile is the same as the first QoS profile; A multicast / broadcast service communication method, wherein the first session management function network element and the second session management function network element are in different areas.

2. The communication method according to claim 1 , wherein the session management function network element is a session management function SMF.

3. The communication method according to claim 1 or 2, wherein the first network element is configured to manage and control Quality of Service (QoS) information of the multicast / broadcast service.

4. said step of determining, by the first network element, a Quality of Service Flow Identifier (QFI) for the multicast / broadcast service, comprising: obtaining, by the first network element, information about the multicast / broadcast service from an application server; determining, by the first network element, the QFI of the multicast / broadcast service based on the information about the multicast / broadcast service; 4. A communication method according to claim 1, comprising:

5. The information about the multicast / broadcast service comprises: The communication method according to claim 4, further comprising the step of: providing the multicast / broadcast service requirement information;

6. The communication method of claim 5 , wherein the requirement information of the multicast / broadcast service includes a bandwidth requirement or a delay requirement of the multicast / broadcast service.

7. 1. A multicast / broadcast service communication method, the method comprising: receiving, by a first Session Management Function network element, from a first network element, a Quality of Service Flow Identifier (QFI) of the multicast / broadcast service; sending, by the first session management function network element, the QFI and a first quality of service profile (QoS profile) to a first access network device based on the QFI; receiving, by a second Session Management Function network element, the QFI of the multicast / broadcast service from the first network element; transmitting, by the second session management function network element, the QFI and a second QoS profile to a second access network device based on the QFI; the second QoS profile is the same as the first QoS profile; The method of communication, wherein the first session management function network element and the second session management function network element are in different areas.

8. 8. The communication method of claim 7, wherein the second access network device is connected to a User Plane Function (UPF) managed by the second Session Management Function network element, and the first access network device is connected to a UPF managed by the first Session Management Function network element.

9. A communication system, the communication system including a first network element, a first session management function network element, and a second session management function network element; The first network element is configured to perform the method according to any one of claims 1 to 6, The first session management function network element is configured to receive the QFI from the first network element, and send the QFI and a first quality of service profile (QoS profile) to a first access network device based on the QFI; the second session management function network element is configured to receive the QFI from the first network element and send the QFI and a second QoS profile to a second access network device based on the QFI; the first QoS profile is the same as the second QoS profile; A communication system, wherein the first session management function network element and the second session management function network element are in different areas.

10. 10. The communication system of claim 9, wherein the second access network device is connected to a User Plane Function (UPF) managed by the second Session Management Function network element, and the first access network device is connected to a UPF managed by the first Session Management Function network element.

11. 10. A communications device, the communications device comprising one or more processors and a communications interface, the one or more processors and the communications interface configured to support the communications device in performing a communications method according to any one of claims 1 to 6 or a communications method according to claim 7.

12. 10. A computer-readable storage medium comprising computer instructions that, when run on a computer, enable the computer to perform the communication method of any one of claims 1 to 6 or the communication method of claim 7.

13. A computer program comprising one or more computer instructions, which, when loaded and executed on a computer, performs the communication method according to any one of claims 1 to 6 or the communication method according to claim 7.

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