Communication method and apparatus for multicast / broadcast services

Abstract

This application provides a communication method and apparatus for multicast / broadcast services. The method includes: A network device obtains reference location information of a terminal. The reference location information represents a reference location of the terminal. When the reference location of the terminal is within a service area of ​​a first multicast / broadcast service, the network device triggers a target access network device of the terminal to allocate or establish a data resource for transmitting the first multicast / broadcast service to the terminal. When the reference location of the terminal is outside the service area of ​​the first multicast / broadcast service, the network device triggers a target access network device of the terminal not to allocate or establish a data resource for transmitting the first multicast / broadcast service to the terminal. According to the method provided in this application, session management on a local multicast / broadcast service can ensure that a core network element dynamically and flexibly interacts with an access network device when a terminal moves into or out of a service area, thereby effectively saving network resources.

Description

[Technical Field]

[0002] This application relates to the field of communication technologies, and in particular to communication methods and apparatus for multicast / broadcast services. [Background technology]

[0003] With the development of mobile Internet, mobile high-definition video services are rapidly increasing. Users are gradually shifting from watching video programs via fixed networks to watching video programs via mobile phone terminals and mobile networks. Video services are having an increasingly strong impact on mobile networks.

[0004] To overcome the aforementioned challenges, supporting 5G Multicast / Broadcast Service (5MBS) functionality based on the 5th generation (5G) mobile communication network architecture has become an important research topic.

[0005] 5 The main research topic of MBS research is local multicast / broadcast services (Local MBS). Local multicast / broadcast services mean that multicast / broadcast services are distributed only to a specific area, which is sometimes called a distribution area or service area. Specifically, a distribution area may be a cell or a tracking area (TA).

[0006] In the above research topic, how to perform multicast / broadcast session management to efficiently save network resources when a terminal moves into or out of the multicast / broadcast service area is an urgent issue to be solved. Summary of the Invention

[0007] An embodiment of this application provides a communication method for multicast / broadcast services, which enables a network device to dynamically determine the relationship between the reference location information of a terminal and the service area of ​​a first multicast / broadcast service, and flexibly allocate or delete resources to the terminal, thereby improving the utilization rate of network resources, effectively saving network resources, and avoiding resource waste caused by invalid transmission of data of the multicast / broadcast service.

[0008] According to a first aspect, there is provided a communication method for a multicast / broadcast service. The method includes a network device acquiring reference location information of a terminal. The reference location information represents a reference location of the terminal. When the reference location of the terminal is within a service area of ​​a first multicast / broadcast service, the network device triggers a target access network device of the terminal to allocate transmission resources to the terminal. The transmission resources are used to transmit data of the first multicast / broadcast service.

[0009] Regarding the first aspect, in some implementations of the first aspect, the reference location information includes location information of the terminal at a target access network device of the terminal.

[0010] Regarding the first aspect, in some implementations of the first aspect, the location information is a target cell identifier and / or a target access network device identifier for the terminal.

[0011] Regarding the first aspect, in some implementations of the first aspect, the network device includes a terminal session management function network element or a source access network device.

[0012] According to the communication method for multicast / broadcast services provided in this application, when a network device dynamically determines that the reference location information of a terminal is within the service area of ​​a first multicast / broadcast service, the T-gNB of the terminal is triggered to allocate resources to the terminal or establish resources for the terminal, thereby improving the utilization of network resources.

[0013] According to a second aspect, there is provided a communication method for multicast / broadcast services. The method includes a network device acquiring reference location information of a terminal. The reference location information represents a reference location of the terminal. When the reference location of the terminal is outside a service area of ​​a first multicast / broadcast service, the network device initiates release of a first transmission resource of the terminal. The first transmission resource is used to transmit data of the first multicast / broadcast service.

[0014] The network device may initiate the release of the first transmission resource of the terminal, or the network device may trigger the deletion or initiate the deletion of the first transmission resource.

[0015] According to the communication method for multicast / broadcast services provided in this application, when a network device determines that the reference location of a terminal is outside the service area of ​​a first multicast / broadcast service, the network device triggers / initiates the release / deletion of a first transmission resource of the terminal, thereby effectively saving network resources and avoiding resource waste caused by invalid transmissions.

[0016] With respect to the second aspect, in some implementations of the second aspect, the first transmission resource includes a resource used by the terminal to transmit data of the first multicast / broadcast service via a target access network device of the terminal.

[0017] Regarding the second aspect, in some implementations of the second aspect, the network device determines that the terminal is outside a service area of ​​the first multicast / broadcast service based on the reference location information.

[0018] Regarding the second aspect, in some implementations of the second aspect, the reference location information includes location information of the terminal in an access network device currently serving the terminal, or location information of the terminal in a target access network device for the terminal.

[0019] Regarding the second aspect, in some implementations of the second aspect, when the network device is a session management function network element, the obtaining of the reference location information of the terminal by the network device includes receiving a first message by the session management function network element, the first message including the reference location information.

[0020] Regarding the second aspect, in some implementations of the second aspect, the first message further includes identification information of the first multicast / broadcast service.

[0021] Regarding the second aspect, in some implementations of the second aspect, the first message is a protocol data unit (PDU) session context update request or location information provision.

[0022] Regarding the second aspect, in some implementations of the second aspect, the method further includes the session management function network element subscribing to reference location information of the terminal from the access and mobility management network element. The receiving of the first message by the session management function network element includes the session management function network element receiving the reference location information of the terminal from the access and mobility management network element.

[0023] Regarding the second aspect, in some implementations of the second aspect, when the network device is a session management function network element, initiating the release of the first transmission resource includes the session management function network element notifying a user plane function network element (UPF) to release the first transmission resource and / or the session management function network element notifying a target access network device of the terminal to release the first transmission resource. Specifically, when the first transmission resource is a radio bearer corresponding to a QoS flow corresponding to a first multicast / broadcast service, it is understood that the first transmission resource has been terminated if the session management function network element only notifies a target access network device of the terminal to release the first transmission resource. It will be understood that the first transmission resource is released when the first transmission resource is a QoS flow corresponding to a first multicast / broadcast service and the session management function network element notifies the user plane function network element to release the first transmission resource and notifies the target network device of the terminal to release the first transmission resource.

[0024] With respect to the second aspect, in some implementations of the second aspect, the session management function network element notifying the UPF to release the first transmission resource includes the session management function network element sending an N4 session modification request or a Packet Forwarding Control Protocol (PFCP) session modification request to the UPF to notify the UPF to release the first transmission resource.

[0025] According to the communication method for multicast / broadcast services provided in this application, when a session management function network element determines that the reference location of a terminal is outside the service area of ​​a first multicast / broadcast service, the session management function network element notifies the PFCP session context in which the session management function network element interacts with the UPF to release multicast / broadcast transmission resources. Through the processes and operations performed by the session management function network element, this solution can effectively save network resources and avoid resource waste caused by invalid transmission of data for the multicast / broadcast service.

[0026] With regard to the second aspect, in some implementations of the second aspect, the method further includes, when the network device is a session management function network element, the session management function network element notifying the target network element of the terminal that the first transmission resource is invalid, the session management function network element notifying the target network element of the terminal not to allocate a radio resource corresponding to the first transmission resource, or not sending an identifier of the first transmission resource to the target network element of the terminal.

[0027] The session management function network element notifying the target network device of the terminal not to allocate radio resources corresponding to the first transmission resource may also be the session management function network element notifying the target access network device of the terminal not to establish or prepare radio resources corresponding to the first transmission resource.

[0028] According to the communication method for multicast / broadcast services provided in this application, when a session management function network element determines that the reference location of the terminal is outside the service area of ​​a first multicast / broadcast service, the session management function network element notifies the terminal's target network device not to allocate / establish / prepare transmission resources for data of the first multicast / broadcast service. This solution can effectively save network resources and avoid resource waste caused by invalid transmission of data of the multicast / broadcast service through the processes and operations performed by the session management function network element.

[0029] With respect to the second aspect, in some implementations of the second aspect, the network device initiating the release of the first transmission resource for the terminal includes, when the network device is a source access network device for the terminal, the source access network device notifying a session management function network element to release the first transmission resource.

[0030] According to the communication method for multicast / broadcast services provided in this application, when the source access network device of the terminal determines that the reference location of the terminal is outside the service area of ​​a first multicast / broadcast service, the source access network device of the terminal notifies a session management function network element to release and delete a first transmission resource used to transmit data of the first multicast / broadcast service. Through the processing and operations performed by the source base station, this solution can effectively save network resources and avoid resource waste caused by invalid transmission of data of the multicast / broadcast service.

[0031] According to a third aspect, there is provided a communication method for multicast / broadcast services. The method includes a network device acquiring reference location information of a terminal. The reference location information represents a reference location of the terminal. When the reference location of the terminal is outside a service area of ​​a first multicast / broadcast service, a target access network device does not accept data transfer of the first multicast / broadcast service to the terminal from a source access network device of the terminal.

[0032] According to the communication method for multicast / broadcast services provided in this application, a target access network device performs a determination and processing. When the target access network device determines that the reference location of the terminal is outside the service area of ​​the first multicast / broadcast service, the target access network device does not forward data of the first multicast / broadcast service to the terminal. This solution can effectively save network resources and avoid resource waste caused by invalid forwarding of data of the multicast / broadcast service.

[0033] With respect to the third aspect, in some implementations of the third aspect, the target access network device obtaining reference location information for the terminal includes the target access network device receiving the reference location information for the terminal from the source access network device.

[0034] Regarding the third aspect, in some implementations of the third aspect, the reference location information includes location information of the terminal at a target access network device of the terminal.

[0035] With respect to the third aspect, in some implementations of the third aspect, the method further includes the target access network device notifying the source access network device that it will not accept forwarding of data of the first multicast / broadcast service to the terminal from the source access network device of the terminal.

[0036] According to a fourth aspect, there is provided a communication method for multicast / broadcast services, the method including: a source access network device discovering that a terminal device is subscribed to a first multicast / broadcast service; the source access network device transmitting identification information of a target cell; the identification information of the target cell being carried in N2 session management information (N2 SM information);

[0037] It should be understood that the source access network device discovering that the terminal device is subscribed to the first multicast / broadcast service may be understood as the source access network device determining that the terminal device is subscribed to the first multicast / broadcast service.

[0038] It should be noted that the target cell identity may be carried in an information element in a specific message, parallel to the N2 session management information. The specific message may be a handover required message. It will be understood that the target cell identity is not carried in the N2 session management information, but instead is carried in the handover required message as a separate information element. The information element parallel to the N2 session management information may be the target cell identification information as an information element parallel to the information elements required to be included in the handover required in the prior art, i.e., handover type, target identifier, cause, source to target transparent container, PDU session resource list, message type, AMF new generation application protocol UE ID (NGAP UE ID), and RAN UE NGAP ID.In another example, the target cell identification information serves as an information element in addition to the information elements included in the handover required in the prior art, i.e., handover type, target identifier, cause, source to target transparent container, PDU session resource list, message type, AMF UE NGAP ID, and RAN UE NGAP ID, and is not carried in any of the information elements that must be included in the handover required in the prior art, but is carried in the handover required as an independent information element.

[0039] Referring to the fourth aspect, in some implementations of the fourth aspect, the method further includes receiving, by the source access network device, a measurement report from the terminal device, and determining, based on the measurement report, an identity of a target cell for the terminal device.

[0040] The source access network device may further determine the identity of a target cell for the terminal device based on the load condition.

[0041] For example, in one implementation, the source access network device is overloaded. For example, there are a large number of terminal devices accessing the source access network device. In this case, the source access network device autonomously selects some terminal devices and actively selects target cells to which the terminal devices need to be handed over. The terminal devices autonomously selected by the source access network device may include terminal devices subscribed to the first multicast / broadcast service. In this case, the source access network device may use a locally stored identifier of a neighboring cell identifier contained in a neighboring base station as the identifier of the target cell selected for the terminal device, include the identifier of the target cell in the N2 session management information, and send the N2 session management information to the SMF via the AMF. The identifier of the neighboring cell of the neighboring base station locally stored by the source access network device may be obtained by exchanging parameters with the neighboring access network device when the source access network device is initialized or powered on, or may be obtained by operation, administration, and maintenance (OAM) configuration. There may be one or more neighboring base stations, there may be one or more neighboring cells included in the neighboring base stations, and there may be one or more autonomously selected terminal devices.

[0042] Regarding the fourth aspect, in some implementations of the fourth aspect, the N2 session management information is carried in a handover required. For example, the N2 session management information is a handover required transfer.

[0043] According to a fifth aspect, there is provided a communication method for multicast / broadcast services. The method includes: a source access network device obtaining reference location information of a terminal device. The reference location information indicates a reference location of the terminal device. The source access network device transmits indication information to a session management function network element based on the reference location information. The indication information includes first indication information and / or second indication information. The first indication information indicates that the reference location of the terminal device is outside a service area of ​​a first multicast / broadcast service, and the second indication information indicates that the reference location of the terminal device is within a service area of ​​a second multicast / broadcast service.

[0044] Regarding the fifth aspect, in some implementations of the fifth aspect, the reference location information may include location information of the terminal device in the target access network device, and specifically, may be an identifier of a target cell for the terminal device.

[0045] Regarding the fifth aspect, in some implementations of the fifth aspect, the indication information is carried in N2 session management information.

[0046] Regarding the fifth aspect, in some implementations of the fifth aspect, the indication information is an information element that is parallel to the N2 session management information. The parallel information element is described in the fourth aspect, and the details will not be described again here.

[0047] With respect to the fifth aspect, in some implementations of the fifth aspect, the N2 session management information is carried in a handover request, and the N2 session management information is a handover required transfer.

[0048] According to a sixth aspect, there is provided a communication method for a multicast / broadcast service. The method includes a session management function network element receiving first indication information. The first indication information indicates that a reference location of a terminal device is outside a service area of ​​a first multicast / broadcast service. The session management function network element initiates release of first transmission resources of the terminal device based on the first indication information. The first transmission resources are used to transmit data of the first multicast / broadcast service.

[0049] Regarding the sixth aspect, in some implementations of the sixth aspect, the method further includes the session management function network element receiving second indication information. The second indication information indicates that the reference location of the terminal device is within a service area of ​​the second multicast / broadcast service. Based on the second indication information, the session management function network element initiates a target access network device of the terminal device to configure second transmission resources for the terminal device. The second transmission resources are used to transmit data of the second multicast / broadcast service.

[0050] Regarding the sixth aspect, in some implementations of the sixth aspect, the first indication information and the second indication information are carried in N2 session management information.

[0051] Regarding the sixth aspect, in some implementations of the sixth aspect, the first indication information and the second indication information are information elements parallel to the N2 session management information. The parallel information elements are described in the fourth aspect, and the details will not be described again here.

[0052] With respect to the sixth aspect, in some implementations of the sixth aspect, the N2 session management information is carried in a handover request, and the N2 session management information is a handover required transfer.

[0053] According to a seventh aspect, there is provided a communication method for multicast / broadcast services, the method including: a session management function network element receiving indication information indicating that a reference location of a terminal device is within a service area of ​​a first multicast / broadcast service. The session management function network element initiates, based on the indication information, a target access network device for the terminal device to configure a first transmission resource for the terminal device, the first transmission resource being used to transmit data of the first multicast / broadcast service.

[0054] Regarding the seventh aspect, in some implementations of the seventh aspect, the indication information is carried in N2 session management information.

[0055] With respect to the seventh aspect, in some implementations of the seventh aspect, the N2 session management information is carried in a handover request, and the N2 session management information is a handover required transfer.

[0056] Regarding the seventh aspect, in some implementations of the seventh aspect, the indication information is an information element that is parallel to the N2 session management information. The parallel information element is described in the fourth aspect, and the details will not be described again here.

[0057] Based on the above solution, the processing logic of the session management function network element is freed up because the processing logic is such that the source access network device determines whether the target cell is outside the service area of ​​the first multicast / broadcast service and / or within the service area of ​​the second multicast / broadcast service, and then notifies the session management function network element of the determination result in an indication manner. Specifically, for example, when it is determined that the identifier of the target cell is outside the first multicast / broadcast service, the N2 session management information includes identification information of the first multicast / broadcast service and first indication information. The first indication information may be represented, for example, by a binary bit 1 or 0. In another example, when it is determined that the identifier of the target cell is within the second multicast / broadcast service, the N2 session management information includes second indication information and identification information of the second multicast / broadcast service. The second indication information may be represented, for example, by a binary bit 1 or 0.

[0058] According to an eighth aspect, there is provided a communication method for multicast / broadcast services. The method includes a target access network device receiving a notification from a session management function network element. The notification notifies the terminal that a first transmission resource is invalid, the first transmission resource being used to transmit data of the first multicast / broadcast service. The target access network device does not allocate radio resources corresponding to the first transmission resource, and / or the target access network device sends indication information to the source access network device of the terminal. The indication information indicates that the target access network device does not accept transfer of data of the first multicast / broadcast service from the source access network device to the terminal.

[0059] According to the communication method for multicast / broadcast services provided in this application, the solution can effectively save network resources through the processing and operations performed by the target access network device, and can avoid resource waste caused by invalid forwarding of multicast / broadcast service data.

[0060] According to a ninth aspect, there is provided a communication apparatus for multicast / broadcast services, the apparatus including a processing module configured to acquire reference location information of a terminal. The reference location information represents a reference location of the terminal. When the reference location of the terminal is within a service area of ​​a first multicast / broadcast service, the processing module triggers a target access network device of the terminal to allocate transmission resources to the terminal. The transmission resources are used to transmit data of the first multicast / broadcast service.

[0061] Based on the beneficial effects of the aforementioned solutions, please refer to the corresponding description in the first aspect. For the sake of simplicity, the details will not be described again in this application.

[0062] Regarding the ninth aspect, in some implementations of the ninth aspect, the reference location information includes location information of the terminal at a target access network device of the terminal.

[0063] Regarding the ninth aspect, in some implementations of the ninth aspect, the location information is a target cell identifier and / or a target access network device identifier for the terminal.

[0064] With respect to the ninth aspect, in some implementations of the ninth aspect, the apparatus includes a terminal session management function network element or a source access network device.

[0065] According to a tenth aspect, there is provided a communications device for multicast / broadcast services. The device includes a processing module configured to acquire reference location information of a terminal. The reference location information represents a reference location of the terminal. When the reference location of the terminal is outside a service area of ​​a first multicast / broadcast service, the processing module triggers release of a first transmission resource of the terminal. The first transmission resource is used to transmit data of the first multicast / broadcast service.

[0066] Based on the beneficial effects of the aforementioned solutions, please refer to the corresponding description in the second aspect. For the sake of simplicity, the details will not be described again in this application.

[0067] With respect to the tenth aspect, in some implementations of the tenth aspect, the first transmission resource includes a resource used to transmit data of the first multicast / broadcast service via a target access network device of the terminal.

[0068] With respect to the tenth aspect, in some implementations of the tenth aspect, the processing module is further configured to determine, based on the reference location information, that the terminal is outside a service area of ​​the first multicast / broadcast service.

[0069] With respect to the tenth aspect, in some implementations of the tenth aspect, the reference location information includes location information of the terminal in an access network device currently serving the terminal, or location information of the terminal in a target access network device for the terminal.

[0070] With respect to the tenth aspect, in some implementations of the tenth aspect, when the device is a session management function network element, the device further includes a transceiver module configured to receive a first message, the first message including reference location information.

[0071] With regard to the tenth aspect, in some implementations of the tenth aspect, the first message further includes identification information of the first multicast / broadcast service.

[0072] With respect to the tenth aspect, in some implementations of the tenth aspect, the first message is a protocol data unit (PDU) session context update request or location information provision.

[0073] With respect to the tenth aspect, in some implementations of the tenth aspect, the transceiver module is further configured to subscribe to reference location information of the terminal from the access and mobility management network element, and receiving the first message by the transceiver module includes receiving, by the transceiver module, the reference location information of the terminal from the access and mobility management network element.

[0074] With respect to the tenth aspect, in some implementations of the tenth aspect, when the apparatus is a session management function network element, the transceiver module is further configured to notify a user plane function network element UPF to release the first transmission resource, and / or the transceiver module is further configured to notify a target access network device of the terminal to release the first transmission resource.

[0075] With respect to the tenth aspect, in some implementations of the tenth aspect, the transceiver module is further configured to send an N4 session modification request or a Packet Forwarding Control Protocol (PFCP) session modification request to the UPF to notify the UPF to release the first transmission resource.

[0076] With regard to the tenth aspect, in some implementations of the tenth aspect, when the apparatus is a session management function network element, the transceiver module is further configured to notify the target access network device of the terminal that the first transmission resource is invalid, or the transceiver module is further configured to notify the target access network device of the terminal not to allocate a radio resource corresponding to the first transmission resource, or the transceiver module does not send an identifier of the first transmission resource to the target access network device of the terminal.

[0077] With respect to the tenth aspect, in some implementations of the tenth aspect, when the apparatus is a source access network device for the terminal, the apparatus further includes a transceiver module configured to notify a session management function network element to release the first transmission resource.

[0078] According to an eleventh aspect, there is provided a communications apparatus for multicast / broadcast services, the apparatus including a processing module configured to acquire reference location information of a terminal, the reference location information representing a reference location of the terminal, and when the reference location of the terminal is outside a service area of ​​a first multicast / broadcast service, the processing module rejects / discards data transfer of the first multicast / broadcast service to the terminal from a source access network device of the terminal.

[0079] Based on the beneficial effects of the aforementioned solutions, please refer to the corresponding description in the third aspect. For the sake of simplicity, the details will not be described again in this application.

[0080] With regard to the eleventh aspect, in some implementations of the eleventh aspect, the transceiver module is configured to receive reference location information of the terminal from a source access network device.

[0081] Regarding the eleventh aspect, in some implementations of the eleventh aspect, the reference location information includes location information of the terminal at a target access network device of the terminal.

[0082] With respect to the eleventh aspect, in a possible implementation of the eleventh aspect, the transceiver module is further configured to notify the source access network device that the apparatus does not accept forwarding of data of the first multicast / broadcast service to the terminal from the source access network device of the terminal.

[0083] According to a twelfth aspect, there is provided a communications device for multicast / broadcast services. The device includes a transceiver module and a processing module. The transceiver module is configured to receive a notification from a session management function network element. The notification notifies the terminal that a first transmission resource is invalid, and the first transmission resource is used to transmit data of the first multicast / broadcast service. The processing module is configured to skip allocating a radio resource corresponding to the first transmission resource. Additionally / alternatively, the transceiver module is further configured to send indication information to a source access network device of the terminal. The indication information indicates that the transceiver module will not accept transfer of data of the first multicast / broadcast service from the source access network device to the terminal.

[0084] Based on the beneficial effects of the aforementioned solutions, please refer to the corresponding description in the fourth aspect. For the sake of simplicity, the details will not be described again in this application.

[0085] According to a thirteenth aspect, there is provided a communication device for multicast / broadcast services. The device includes a memory and a processor. The memory is configured to store computer instructions. The processor executes the computer instructions stored in the memory to enable the device to perform a communication method for multicast / broadcast services in any of the possible implementations of the first to eighth aspects.

[0086] According to a fourteenth aspect, there is provided a computer-readable storage medium storing a computer program, which, when executed by a communication device for multicast / broadcast services, enables the device to perform a communication method for multicast / broadcast services in any of the possible implementations of the first to eighth aspects. [Brief explanation of the drawings]

[0087] [Figure 1] 1 is a schematic diagram of a network architecture to which an embodiment of this application is applicable.

[0088] [Figure 2] 1 illustrates a network architecture used for multicast / broadcast services to which one embodiment of this application is applicable.

[0089] [Figure 3] 1 is a schematic flowchart of data transmission in unicast mode.

[0090] [Figure 4] 1 is a schematic flowchart of data transmission in multicast / broadcast mode.

[0091] [Figure 5]5 is a schematic flowchart of a communication method 500 for multicast / broadcast services, according to an embodiment of the present application.

[0092] [Figure 6] 1 illustrates a multicast / broadcast service scenario according to one embodiment of this application.

[0093] [Figure 7] 7 is a schematic flowchart of a communication method 700 for multicast / broadcast services, according to an embodiment of the present application.

[0094] [Figure 8A] 8 is a schematic flowchart of a communication method 800 for multicast / broadcast services, according to an embodiment of the present application. [Figure 8B] 8 is a schematic flowchart of a communication method 800 for multicast / broadcast services, according to an embodiment of the present application.

[0095] [Figure 9] 9 is a schematic flowchart of a communication method 900 for multicast / broadcast services, according to an embodiment of the present application.

[0096] [Figure 10A] 10 is a schematic flowchart of a communication method 1000 for multicast / broadcast services according to an embodiment of the present application. [Figure 10B] 10 is a schematic flowchart of a communication method 1000 for multicast / broadcast services according to an embodiment of the present application.

[0097] [Figure 11] 11 is a schematic flowchart of a communication method 1100 for multicast / broadcast services, according to an embodiment of the present application.

[0098] [Figure 12] 12 is a schematic flowchart of a communication method 1200 for multicast / broadcast services, according to an embodiment of the present application.

[0099] [Figure 13] 13 is a schematic flowchart of a communication method 1300 for multicast / broadcast services, according to an embodiment of the present application.

[0100] [Figure 14A] 14 is a schematic flowchart of a communication method 1400 for multicast / broadcast services, according to an embodiment of the present application. [Figure 14B] 14 is a schematic flowchart of a communication method 1400 for multicast / broadcast services, according to an embodiment of the present application.

[0101] [Figure 15] 15 is a schematic flowchart of a communication method 1500 for multicast / broadcast services, according to an embodiment of the present application.

[0102] [Figure 16A] 16 is a schematic flowchart of a communication method 1600 for multicast / broadcast services, according to an embodiment of the present application. [Figure 16B] 16 is a schematic flowchart of a communication method 1600 for multicast / broadcast services, according to an embodiment of the present application.

[0103] [Figure 17] 17 is a schematic flowchart of a communication method 1700 for multicast / broadcast services, according to an embodiment of the present application.

[0104] [Figure 18]18 is a schematic flowchart of a communication method 1800 for multicast / broadcast services, according to an embodiment of the present application.

[0105] [Figure 19] 19 is a schematic flowchart of a communication method 1900 for multicast / broadcast services, according to an embodiment of the present application.

[0106] [Figure 20] 2 is a schematic flowchart of a communication method 2000 for multicast / broadcast services according to an embodiment of the present application.

[0107] [Figure 21] 21 is a schematic flowchart of a communication method 2100 for multicast / broadcast services, according to an embodiment of the present application.

[0108] [Figure 22A] 22 is a schematic flowchart of a communication method 2200 for multicast / broadcast services, according to an embodiment of the present application. [Figure 22B] 22 is a schematic flowchart of a communication method 2200 for multicast / broadcast services, according to an embodiment of the present application.

[0109] [Figure 23A] 23 is a schematic flowchart of a communication method 2300 for multicast / broadcast services, according to an embodiment of the present application. [Figure 23B] 23 is a schematic flowchart of a communication method 2300 for multicast / broadcast services, according to an embodiment of the present application.

[0110] [Figure 24] 1 is a schematic block diagram of a communication device for multicast / broadcast services according to an embodiment of the present application.

[0111] [Figure 25] 1 is a schematic block diagram of a communication device for multicast / broadcast services according to an embodiment of the present application.

[0112] [Figure 26] 1 is a schematic block diagram of a communication device for multicast / broadcast services according to an embodiment of the present application.

[0113] [Figure 27] 1 is a schematic diagram of the architecture of a communication system according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0114] 1 is a schematic diagram of a network architecture to which the embodiments of this application are applicable. Each part of the network architecture shown in FIG. 1 will be described below.

[0115] User equipment UE UE 110 may take various forms, including various handheld devices, in-vehicle devices, wearable devices, computing devices or other processing devices connected to wireless modems, terminals, mobile stations (MS), terminals, soft clients, etc. For example, UE 110 may be a water meter, an electricity meter, or a sensor.

[0116] For example, user equipment in embodiments of this application may be an access terminal, a subscriber unit, a subscriber station, a mobile station, a relay station, a remote station, a remote terminal, a mobile device, a user terminal, terminal equipment, a wireless communication device, a user agent, or a user equipment. User equipment may alternatively be a mobile phone, a cordless phone, a session initiation protocol (SIP), a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication capabilities, a computing device or another processing device connected to a wireless modem, an in-vehicle device, a wearable device, user equipment in a 5G network, user equipment in a future evolved public land mobile network (PLMN), user equipment in a future Internet of Vehicles, etc. This is not a limitation of embodiments of this application.

[0117] By way of example and not limitation, in embodiments of this application, a wearable device, also referred to as a wearable intelligent device, is a general term for wearable devices such as glasses, gloves, watches, clothing, and shoes developed by applying wearable technology to the intelligent design of everyday clothing. A wearable device is a portable device that can be worn directly on the body or incorporated into the user's clothing or accessories. A wearable device is not only a hardware device, but also implements powerful functions through software support, data interaction, and cloud interaction. Generalized wearable intelligent devices include full-featured, large devices that can implement full or partial functions without relying on a smartphone, such as smart watches and smart glasses, and devices that focus only on one type of application function and need to be linked to other devices such as smartphones, such as various smart bands and smart jewelry for monitoring physical signs.

[0118] Additionally, the user equipment in the embodiments of this application may alternatively be a user equipment in an Internet of Things (IoT) system. The IoT is an important part of the future development of information technology. The main technical feature of the IoT is to connect objects to a network using communication technology to implement an intelligent network that interconnects people and machines and things with each other. In the embodiments of this application, the IoT technology may implement large-scale connectivity, deep coverage, and terminal power saving using, for example, narrow band (NB) technology. Additionally, in the embodiments of this application, the user equipment may further include sensors such as smart printers, train detectors, and gas pumps. The main functions include collecting data (some user equipment), receiving control information and downlink data for access network devices, transmitting electromagnetic waves, and transmitting uplink data to access network devices.

[0119] A (radio) access network ((R)AN) device 120 is configured to provide network access functionality to authorized user equipment within a particular area, and can use transmission tunnels with different qualities based on the user equipment level, service requirements, etc.

[0120] The (R)AN device, sometimes called RAN for short, is configured to manage radio resources, provide access services to user equipment, and complete the transfer of control signals and user equipment data between user equipment and the core network. The (R)AN may also be understood as a base station in a conventional network.

[0121] For example, an access network device in embodiments of this application may be any communication device having a radio transceiver function and configured to communicate with user equipment, including, but not limited to, an evolved NodeB (eNB), a radio network controller (RNC), a NodeB (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., a Home evolved NodeB, HeNB, or Home NodeB, HNB), a baseband unit (BBU), an access point (AP) in a Wireless Fidelity (Wi-Fi) system, a wireless relay node, a wireless backhaul node, a transmission point (TP), a transmission and reception point (TRP), etc. Alternatively, the access network device may be a gNB or a transmission point (TRP or TP) in a 5G system such as an NR system, or may be one antenna panel or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or may be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU) or a distributed unit (DU).

[0122] In some deployments, a gNB may include a central unit (CU) and a DU. The gNB may further include an active antenna unit (AAU). The CU performs some functions of the gNB, and the DU performs some functions of the gNB. For example, the CU is responsible for processing non-real-time protocols and services and implements radio resource control (RRC) layer and packet data convergence protocol (PDCP) layer functions. The DU is responsible for processing physical layer protocols and real-time services and implements radio link control (RLC) layer, media access control (MAC) layer, and physical (PHY) layer functions. The AAU implements some physical layer processing functions, radio frequency processing, and active antenna-related functions. Information at the RRC layer is ultimately converted to or from information at the PHY layer. Therefore, in this architecture, higher layer signaling, such as RRC layer signaling, may also be considered to be transmitted by the DU or by the DU and AAU. An access network device may be understood to be a device including one or more of a CU node, a DU node, and an AAU node. Additionally, a CU may be classified as an access network device in an access network (radio access network, RAN) or as an access network device in a core network (CN). This is not a limitation in this application.

[0123] The user plane network element 130 is configured to route and forward user plane data, perform quality of service (QoS) processing on the user plane data, and the like.

[0124] In a 5G communication system, the user plane network element may be a user plane function (UPF) network element. In future communication systems, the user plane network element may still be a UPF network element or may have a different name, which is not a limitation in this application.

[0125] The data network element (DN) 140 is a network that provides data transmission.

[0126] In a 5G communication system, a data network element may be a data network element. In future communication systems, a data network element may still be a DN network element or may have a different name. This is not a limitation in this application.

[0127] The access management network element 150 is mainly configured to perform mobility management, access management, etc., and may also be configured to implement other functions other than session management in a mobility management entity (MME) function in a 4G communication system.

[0128] In a 5G communication system, the access management network element may be an access and mobility management function (AMF) network element. In future communication systems, the access management network element may still be an AMF network element or may have another name, which is not limited in this application.

[0129] The session management network element 160 is mainly configured to manage sessions, assign and manage Internet Protocol (IP) addresses of terminals, select termination points that can manage user plane function interfaces and policy control and charging function interfaces, signal downlink data, etc.

[0130] In a 5G communication system, the session management function network element may be a session management function (SMF) network element. In future communication systems, the session management function network element may still be an SMF network element or may have another name, which is not limited in this application.

[0131] The policy control network element 170 is configured to provide policy rule information, for example, to provide policy rules for a control plane function network element (eg, AMF or SMF).

[0132] In a 4G communication system, the policy control network element may be a policy and charging rules function (PCRF) network element. In a 5G communication system, the policy control network element may be a policy control function (PCF) network element. In future communication systems, the policy control network element may still be a PCF network element or may have another name, which is not limited in this application.

[0133] The network slice selection network element 180 is configured to retrieve the PCF associated with the session.

[0134] In a 5G communication system, the network slice selection network element may be a network slice selection function (NSSF) network element. In future communication systems, the network slice selection network element may still be an NSSF network element or may have a different name, which is not a limitation in this application.

[0135] The authentication server 190 is configured to authenticate services, generate keys to implement two-way authentication of terminals, and support a unified authentication framework.

[0136] In a 5G communication system, the authentication server may be an authentication server function (AUSF) network element. In future communication systems, the authentication server function network element may still be an AUSF network element or may have a different name, which is not limited in this application.

[0137] The data management network element 1100 is configured to process terminal identifiers, perform access authentication, registration, mobility management, and the like.

[0138] In a 5G communication system, the data management network element may be a unified data management (UDM) network element. In future communication systems, the unified data management network element may still be a UDM network element or may have a different name, which is not limited in this application.

[0139] The application network element is configured to perform application-sensitive data routing, access network-exposed function network elements, and interact with the policy framework to perform policy control.

[0140] In a 5G communication system, the application network element may be an application function (AF) network element. In future communication systems, the application network element may still be an AF network element or may have a different name, which is not a limitation in this application.

[0141] The network storage network element is configured to maintain real-time information of all network function services within the network.

[0142] In a 5G communication system, the network storage network element may be a Network Repository Function (NRF) network element. In future communication systems, the network storage network element may still be an NRF network element or may have a different name, which is not a limitation in this application.

[0143] It will be understood that the aforementioned network elements or functions may be network elements within a hardware device, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (e.g., a cloud platform).

[0144] Indeed, the network architecture of Figure 1 may further include other network elements or devices, such as, but not limited to, a unified data repository (UDR), a network repository function (NRF), etc.

[0145] In the network architecture shown in Figure 1, the terminal is connected to the AMF via the N1 interface, the RAN is connected to the AMF via the N2 interface, and the RAN is connected to the UPF via the N3 interface.

[0146] The UPFs are connected to each other by the N9 interface, and the UPFs are connected to the DN by the N6 interface.

[0147] The session management function network element controls the UPF via the N4 interface. The AMF is connected to the session management function network element by the N11 interface.

[0148] The AMF retrieves terminal subscription data from the UDM network element via the N8 interface. The Session Management Function network element retrieves terminal subscription data from the UDM network element via the N10 interface.

[0149] The AMF retrieves policy data from the PCF via the N15 interface, and the Session Management Function network element retrieves policy data from the PCF via the N7 interface.

[0150] The AF and PCF are connected by an N5 interface.

[0151] It should be noted that the names of the network elements and the communication interfaces between the network elements in FIG. 1 are simply described using names specified in existing protocols as examples. However, the embodiments of this application are not limited to being applicable only to existing known communication systems. Therefore, the standard names used when using existing protocols as illustrative examples are all functional descriptions. The specific names of network elements, interfaces, signaling, etc. are not intended to be limiting in this application but only represent the functions of the network elements, interfaces, signaling, etc., and may be correspondingly extended to other systems, such as 2G, 3G, 4G, or future communication systems.

[0152] The network architecture shown in Figure 1 is an example for illustrative purposes only, and is not limited to the network architecture to which the embodiments of this application are applicable. The embodiments of this application are applicable to any network architecture that can implement the functions of the network elements described above.

[0153] For example, in some network architectures, network function network element entities such as AMF network elements, session management function network elements, PCF network elements, BSF network elements, and UDM network elements are all referred to as network function (NF) network elements. Alternatively, in some other network architectures, a set of network elements such as AMF network elements, session management function network elements, PCF network elements, BSF network elements, and UDM network elements may be referred to as control plane function network elements.

[0154] The technical solutions in the embodiments of this application may be applied to various communication systems, such as a long-term evolution (LTE) system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD) system, a universal mobile telecommunications system (UMTS), a worldwide interoperability for microwave access (WiMAX) communication system, a fifth generation (5G) system, a new radio (NR) system, or a future network. The technical solutions provided in this application may also be applied to future communication systems, such as a sixth generation mobile communication system. Alternatively, the communication system may be a public land mobile network (PLMN) network, a device-to-device (D2D) communication system, a machine-to-machine (M2M) communication system, an Internet of Things (IoT) communication system, or another communication system.

[0155] In an embodiment of this application, a user equipment or access network device includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also referred to as main memory). The operating system may be one or more types of computer operating systems that implement service processing through processes, such as a Linux operating system, a UNIX operating system, an Android operating system, an iOS operating system, or a Windows operating system. The application layer includes applications such as a browser, an address book, word processing software, and instant messaging software. Additionally, the specific structure of an entity for executing a method provided in an embodiment of this application is not particularly limited in the embodiment of this application, as long as it can run the program record code of the method provided in the embodiment of this application and perform communication according to the method provided in the embodiment of this application. For example, an entity for performing the method provided in the embodiments of this application may be a user equipment or an access network device, or may be a functional module that can call and execute a program in the user equipment or the access network device.

[0156] Additionally, aspects or features of this application may be implemented as a method, apparatus, or article of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" as used in this application covers a computer program accessible from any computer-readable component, carrier, or medium. For example, computer-readable media may include, but are not limited to, magnetic storage components (e.g., hard disks, floppy disks, or magnetic tapes), optical disks (e.g., compact disks (CDs), digital versatile discs (DVDs)), smart cards, and flash memory components (e.g., erasable programmable read-only memory (EPROM), cards, sticks, or key drives). Additionally, various storage media described herein may represent one or more devices and / or other machine-readable media configured to store information. The term "machine-readable storage medium" may include, but is not limited to, wireless channels, and various other media capable of storing, containing, and / or carrying instructions and / or data.

[0157] An embodiment of this application further relates to a multicast method. Figure 2 provides a network architecture used for multicast / broadcast services. This architecture is extended based on the architecture shown in Figure 1. For example, to support multicast / broadcast services / functions, two functional entities may be added, such as a multicast / broadcast session management function (MB-SMF) network element and a multicast broadcast user plane function (MB-UPF) network element.

[0158] It should be noted that the communication method provided in this application can also be applied to transmitting service data in a broadcast manner. When the communication method provided in this application is applied to transmitting data in a broadcast manner, multicast in the description of the embodiments of this application is replaced with broadcast. The specific data transmission procedure is the same as that of multicast, and the details of the broadcast method will not be described again in this application.

[0159] In FIG. 2, the MB-SMF implements the control plane functions of the multicast / broadcast service and is responsible for managing multicast / broadcast service groups and sessions. The MB-SMF may be connected to a multicast / broadcast service server, a multicast / broadcast service function (MBSF) network element, or a network exposure function (NEF) network element to facilitate receiving information related to the multicast / broadcast service (e.g., multicast / broadcast service description). Additionally, the MB-SMF may be connected to a PCF to facilitate creating resources for the multicast / broadcast service. The MBU-UPF may be configured to transmit data for the multicast / broadcast service. Optionally, the MB-SMF may be integrated into the PCF or SMF as a functional module, the MB-UPF may be integrated into the UPF as a functional module, or the MB-SMF and MB-UPF may be deployed separately. This is not a limitation in this application.

[0160] It should be noted that the names of MB-SMF and MB-UPF mentioned above are examples. In a 5G network, MB-SMF or MB-UPF may have other names, which is not limited in this application.

[0161] Hereinafter, first, the main terms of the related art in the embodiments of this application will be explained, and it should be noted that these explanations are intended to facilitate understanding of the embodiments of this application, but should not be considered as limitations on the scope of protection described in the claims of this application.

[0162] (1) Unicast

[0163] In this application, unicast specifically refers to the following:

[0164] Specifically, in the core network layer, unicast refers to transmitting service data to a terminal via a Protocol Data Unit (PDU) session.

[0165] The unicast mode of multicast / broadcast services transmits multicast / broadcast service data to terminals via PDU sessions and is hereinafter sometimes referred to as unicast mode for short. Unicast mode is also called the 5G core individual multicast / broadcast service traffic delivery method.

[0166] The PDU session and system architecture shown in Figure 2 are used as an example below to provide a data transmission procedure in unicast mode. Figure 3 is a schematic diagram of the data transmission procedure in unicast mode. The transmission procedure shown in Figure 3 may be for transmitting data of a unicast service or for transmitting data of a multicast / broadcast service (in unicast mode).

[0167] In Figure 3, three user equipments (UEs) are used as an example, with UE1, UE2, and UE3 each corresponding to a different PDU session. Multicast / broadcast service data transmitted by a content provider (CP) may be transmitted to the UE via a corresponding PDU session. The PDU session in the figure is assumed to be a PDU session associated with the multicast / broadcast service. Specifically, the service transmission path from the CP to the NG-RAN may include a transmission path between the CP and the 5G core network (CN) and a transmission path between the 5G CN and the NG-RAN. The transmission path between the 5G CN and the NG-RAN may be a PDU session tunnel, such as the N3 tunnel between the PSA-UPF and the NG-RAN. Different PDU sessions have different PDU session tunnels. The three PDU session tunnels in this schematic diagram correspond to three UEs. In the air interface, the RAN may transmit service data to UE1, UE2, and UE3 separately in unicast mode, i.e., PTP mode. In the schematic diagram, the service data of the UE may be different (for example, the target address is the IP address of the UE), and the service data of the UE may be transmitted to the UE through independent transmission paths of the UE, respectively.

[0168] (2) Multicast / Broadcast

[0169] In this application, multicast / broadcast specifically refers to the following:

[0170] Specifically, in the core network layer, multicast / broadcast refers to transmitting multicast / broadcast service data to terminal devices via a multicast / broadcast session, which may hereinafter be referred to as the multicast / broadcast mode. The multicast / broadcast mode may also be referred to as the 5G core shared multicast / broadcast service traffic delivery method.

[0171] In an embodiment of this application, the multicast / broadcast mode in the transmission mode determined by the SMF means transmitting multicast / broadcast service data to a terminal device via a multicast / broadcast session. The multicast / broadcast service may be described using information about the multicast / broadcast service. The information about the multicast / broadcast service includes at least description information about the multicast / broadcast service. The description information about the multicast / broadcast service may include description information about one or more multicast / broadcast service flows. The description information about the multicast / broadcast service flow includes at least one of the quality of service index (QoS flow identifier, QFI) that the multicast / broadcast service flow should have, characteristic information about the multicast / broadcast service flow (e.g., the destination address, destination port number, and source address of the multicast / broadcast service flow), and QoS requirements for the multicast / broadcast service flow (e.g., jitter, delay, packet loss rate, and bandwidth). The QoS requirements of the multicast / broadcast service flow are for establishing the multicast / broadcast QoS flow. The PDU session tunnel corresponds to a UE, and service data in the PDU session tunnel may be transmitted in the form of a unicast QoS flow. In an embodiment of this application, the PDU session tunnel may be further configured to transmit a unicast QoS flow to which a multicast / broadcast QoS flow corresponding to a multicast / broadcast service is mapped. Note that the PDU session is at the UE level, and the multicast / broadcast session is at the service level. One PDU session of one UE may be associated with multiple multicast / broadcast services.In other words, a UE may join at least one multicast / broadcast service via a PDU session. A multicast / broadcast session may serve the multicast / broadcast service. The multicast / broadcast session includes a unicast or multicast tunnel from the data network to the core network device and then to the radio access network, and unicast or multicast / broadcast air interface resources allocated by the radio access network for transmitting the multicast / broadcast service.

[0172] The information about the multicast / broadcast service may include, in addition to descriptive information about the multicast / broadcast service, further information about the terminals, such as identifiers of one or more terminals that are allowed (or request) to participate in the multicast / broadcast service, identifiers of one or more groups of terminals, etc.

[0173] The system architecture shown in Figure 2 is used as an example for providing a data transmission procedure in multicast / broadcast mode. Figure 4 is a schematic flowchart of data transmission in multicast / broadcast mode. The transmission procedure shown in Figure 4 may be for transmitting data for multicast / broadcast services.

[0174] In FIG. 4, data of a multicast / broadcast service may be transmitted from the CP to UE1, UE2, and UE3. The transmission path of the multicast / broadcast service from the CP to the NG-RAN may include the transmission path between the CP and the 5G CN and the transmission path between the 5G CN and the NG-RAN. The transmission path from the 5G CN to the NG-RAN may be a multicast / broadcast session tunnel, i.e., the N3 tunnel between the MB-UPF and the NG-RAN. The multicast / broadcast session tunnel is shared by UE1, UE2, and UE3. In the air interface, the RAN may transmit data of the multicast / broadcast service to UE1, UE2, and UE3 in PTM mode, i.e., only one piece of data needs to be transmitted, and all three UEs can receive the data. In the example of FIG. 4, only one piece of data of the multicast / broadcast service is transmitted on the transmission path from the CP to the UEs, and multiple UEs may receive the data simultaneously.

[0175] In the multicast / broadcast mode, service data may be transmitted to all target nodes at once, or service data may be transmitted only to specific objects. Therefore, in the multicast mode, point-to-multipoint transmission between one sending node and multiple receiving nodes may be implemented, thereby solving the problem of low efficiency of the unicast mode.

[0176] An access network device supporting multicast / broadcast functionality may be understood as the access network device supporting transmitting data of a multicast / broadcast service in a multicast / broadcast mode.

[0177] An access network device that does not support the multicast / broadcast function may be understood as meaning that the access network device does not support transmitting multicast / broadcast service data in multicast / broadcast mode, or that the access network device supports transmitting multicast / broadcast service data or PDU session data only in unicast mode. An access network device that does not support the multicast / broadcast function may implement network services for terminal devices via PDU sessions. An access network device that supports the multicast / broadcast function may receive multicast / broadcast service data from the core network via a multicast / broadcast session tunnel and transmit the multicast / broadcast service data to multiple terminal devices that have subscribed to the multicast / broadcast service. After arriving at the RAN, the multicast / broadcast service data is processed by the RAN's service data adaptation protocol (SDAP) layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, media access control (MAC) layer, and physical layer (PHY), and then transmitted to all UEs that want to receive the multicast / broadcast service data.

[0178] The first transmission resource may be a QoS flow corresponding to the first multicast / broadcast service and / or a radio bearer to which the QoS flow is mapped / corresponding. The radio bearer may be, for example, a data radio bearer (DRB) or a multicast radio bearer (MRB). The first QoS flow is used to transmit the first multicast / broadcast service and may be a unicast QoS flow to which the multicast / broadcast service is mapped or corresponding, or may be a multicast / broadcast QoS flow. The unicast QoS flow is a QoS flow used to transmit service data in a PDU session. Since the PDU session is at the UE level or at UE granularity, the unicast QoS flow is at the UE granularity or at the UE level. The multicast / broadcast QoS flow is a QoS flow used to transmit data of a multicast / broadcast service in a multicast / broadcast session. Since the multicast / broadcast session is at the service level or at service granularity, the multicast / broadcast QoS flow is at the service level or at service granularity.

[0179] If the cell or access network does not support the multicast / broadcast functionality, the multicast / broadcast service may be transmitted using a unicast QoS flow and DRB. When the access network device or cell supports the multicast / broadcast functionality, the multicast / broadcast service is transmitted via a multicast / broadcast QoS flow and a radio bearer corresponding to the multicast / broadcast QoS flow (e.g., a multicast radio bearer MRB).

[0180] It should be noted that multicast referred to in this application is also called groupcast. Additionally, multicast / broadcast may be replaced with multicast or broadcast. This is not intended to be limiting.

[0181] The technical solutions of this application will be described below with reference to the accompanying drawings.

[0182] 5 is a schematic flowchart of a communication method 500 for multicast / broadcast services according to one embodiment of this application. The method may be applied to a process in which a terminal is handed over from a source access network (source-gNB, S-gNB) device to a target access network (target-gNB, T-gNB) device, or may be applied to a process in which a terminal is handed over between co-site cells, i.e., a process in which a terminal is handed over from one cell to another target cell within the same access network device. The method 500 includes at least the following steps:

[0183] S510. The network device obtains the reference location information of the terminal.

[0184] The reference location information may represent a reference location of the terminal. The reference location may be location information of the terminal in an access network device currently serving the terminal. The location information may include an identifier of a cell in which the terminal is currently located. Alternatively, the reference location may be location information of the terminal in a target access network device of the terminal. The location information includes at least one of a cell identifier, an access network device identifier, a tracking area identifier, and a public land mobile network (PLMN) identifier. Additionally, the location information may include global positioning system (GPS) geographic location information, a sector identifier, a PCI, an antenna identifier, a DU identifier, etc.

[0185] Optionally, when the reference location information includes location information of the terminal in an access network device currently serving the terminal, the location information may be a combination of one or more of an identifier of a current serving cell, an identifier of an access network currently serving the terminal, an identifier of a current tracking area, etc.

[0186] Optionally, when the reference location information includes location information of the terminal at the T-gNB of the terminal, the location information may be one or more of a target cell identifier, a T-gNB identifier, a target tracking area identifier, etc.

[0187] For example, when a co-site cell handover is performed on a terminal, the reference location information may be location information of the access network device currently serving the terminal, such as the identifier of the target cell where the terminal is currently located. When a non-co-site handover is performed on a terminal, the reference location information may be location information of the terminal at the T-gNB of the terminal, such as the identifier of the target cell of the terminal and / or the identifier of the T-gNB of the terminal. Co-site may be the scenario shown in Figure 6. In Figure 6, the access network device is an access network device that does not support multicast / broadcast functionality, and the service area of ​​the first multicast / broadcast service is cell 1 and cell 3 of the access network device. Scenarios that may be included in non-co-site handover may include N2 handover and Xn handover.

[0188] S520. When the reference location of the terminal is within the service area of ​​the first multicast / broadcast service, the network device triggers the target access network device of the terminal to allocate transmission resources to the terminal.

[0189] S520 may be replaced with the following: when the reference location of the terminal is within the service area of ​​the first multicast / broadcast service, the network device allocates transmission resources to the terminal or triggers an access network device of a cell in which the terminal is currently located to establish transmission resources for the terminal based on the reference location of the terminal and the service area of ​​the first multicast / broadcast service, or triggers a target access network device of the terminal to allocate transmission resources to the terminal.

[0190] Furthermore, the network device may trigger a target access network device of the terminal to allocate transmission resources to the terminal based on a measurement report. For example, when the network device is a source base station, the source base station triggers a target access network device of the terminal to allocate transmission resources to the terminal after receiving a measurement report during Xn handover.

[0191] Furthermore, the network device may trigger the target access network device of the terminal to allocate transmission resources to the terminal based on the PDU session context update request. The PDU session context update request may be an Nsmf_PDUSession_UpdateSMContext request. For example, during N2 handover when the network device is an SMF, the SMF triggers the access network device of the terminal to allocate transmission resources to the terminal device after receiving the Nsmf_PDUSession_UpdateSMContext request.

[0192] The transmission resource may be for transmitting data of a first multicast / broadcast service, and the data of the first multicast / broadcast service may be, for example, a radio bearer.

[0193] Optionally, the network device may be an SMF of the terminal or an S-gNB.

[0194] When the network device is an SMF, triggering an access network device of a cell in which the terminal is currently located to allocate transmission resources to the terminal may be the SMF triggering the access network device of the cell in which the terminal is currently located to establish transmission resources for the terminal.When the network device is an SMF or an S-gNB, triggering a target access network device for the terminal to allocate transmission resources to the terminal may be the SMF or an S-gNB triggering a target access network device for the terminal to allocate transmission resources to the terminal, which may apply to a process in which the terminal is handed over from a source access network device to a target access network.

[0195] The triggering process may be, for example, the SMF sending indication information to the access network device of the cell in which the terminal is currently located to trigger the process, or the SMF or S-gNB sending indication information to the target access network device of the terminal to trigger the transmission resource allocation process, which is not limited in this application.

[0196] According to the communication method for multicast / broadcast services provided in this application, when a network device dynamically determines that the reference location information of a terminal is within the service area of ​​a first multicast / broadcast service, the T-gNB of the terminal is triggered to allocate resources to the terminal, thereby improving the utilization of network resources.

[0197] Hereinafter, the method 500 in this embodiment of the present application will be described using an example in which the network device is an SMF and an example in which the network device is an S-gNB. Specifically, for example, Figures 7 to 9 will be described using an example in which the network device is an SMF.

[0198] First, an explanation is provided using an example where the network device is an SMF.

[0199] Figure 7 shows a schematic flowchart of performing co-site cell handover for a terminal when the network device is an SMF.

[0200] S701. The access network device reports the terminal's reference location information to the AMF.

[0201] Specifically, the reference location information may be location information of the access network device currently serving the terminal. For example, when the terminal moves from cell 2 to cell 3, the access network device may report an identifier of cell 3 to the AMF. In this case, the identifier of cell 3 may be the aforementioned location information.

[0202] S702.SMF determines that the current access network device supports a first multicast / broadcast service.

[0203] The current access network device of a terminal may be understood as the access network device that is currently serving the terminal.

[0204] The SMF determines that the current access network device supports the first multicast / broadcast service, for example, when the UE requests to join a multicast / broadcast session using a PDU session modification request, the AMF reports the multicast / broadcast capability of the access network device currently accessed by the UE, and the SMF determines that the current access network device supports the first multicast / broadcast service based on the multicast / broadcast capability of the access network device.

[0205] S703.SMF subscribes to terminal location information from AMF.

[0206] S703 is an optional step. The AMF may proactively report the location information of the terminal to the SMF, or may report the location information of the terminal based on a request from the SMF. This is not limited to this.

[0207] S704.AMF reports the terminal location information to SMF.

[0208] Specifically, the AMF may report the identifier of cell 3 to the SMF.

[0209] S705: The SMF allocates transmission resources to the terminal.

[0210] Specifically, the SMF continues to execute the procedure for the terminal to join the multicast / broadcast service based on the terminal's location information, e.g., assigning or adding information about the unicast QoS flow to which the multicast / broadcast QoS flow mapping is mapped to the PDU session associated with the multicast / broadcast service.

[0211] It should be noted that a PDU session associated with a multicast / broadcast service may also be called a unicast fall-back PDU session, a 5GC shared delivery method to individual delivery method switch PDU session, a PDU session corresponding to the 5GC individual MBS traffic delivery method, a PDU session corresponding to the 5GC individual delivery method, or a PDU session corresponding to the individual delivery method.

[0212] It should be understood that the transmission resources may be for transmitting data of the first multicast / broadcast service. Note that resource allocation may also be understood as establishing a QoS flow used to transmit data of the multicast / broadcast service, which is not a limitation in this application.

[0213] According to the communication method for multicast / broadcast services provided in this application, when the SMF dynamically determines that the reference location information of the terminal is within the service area of ​​the first multicast / broadcast service, the access network device currently serving the terminal is triggered to allocate resources to the terminal or establish resources for the terminal, thereby improving the utilization of network resources.

[0214] 8A and 8B, this embodiment provides a schematic flowchart of performing N2 handover for a terminal between non-co-site cells. In the embodiment shown in FIG. 8A and 8B, an example in which the network device is an SMF is used for explanation.

[0215] S801. The UE sends a measurement report to the S-gNB.

[0216] In response to this, the S-gNB receives the measurement report and determines to hand over the UE to the T-gNB based on the measurement report. The determination to hand over the UE to the T-gNB based on the measurement report belongs to the prior art and will not be described in detail.

[0217] S802. The S-gNB sends a handover required to the source AMF (S-AMF). For example, the "handover required" includes PDU session information of the UE to be handed over, and the PDU session information may include an identifier of the PDU session and QoS information corresponding to the unicast QoS flow included in the PDU session.

[0218] The QoS information of a unicast QoS flow includes a QFI and a QoS parameter.

[0219] Furthermore, if the PDU session of the UE is associated with a multicast / broadcast service, which may be, for example, a first multicast / broadcast service, the PDU session information may further include information about a unicast QoS flow to which the multicast / broadcast QoS flow is mapped. For example, the PDU session is associated with the first multicast / broadcast service, and the PDU session information may further include an identifier of the first unicast QoS flow, and there is a mapping relationship between the first unicast QoS flow and the multicast / broadcast QoS flow used to transmit data of the first multicast / broadcast service.

[0220] The "handover request" further includes a target identifier (Target ID), which may be the identification information of the target cell to which the UE is handed over.

[0221] Additionally, the "handover request" may further include N2 SM information (N2 SM information). If the N2 SM information indicates that there is no direct forwarding tunnel between the S-gNB and the T-gNB, it indicates that an indirect forwarding tunnel can be established between the S-gNB and the T-gNB. In this case, the N2 SM information may include indirect forwarding tunnel information allocated by the S-gNB.

[0222] The "handover request" may further include an identifier of a QoS flow that the S-gNB expects to forward through the forwarding tunnel. For example, if a multicast / broadcast QoS flow needs to be forwarded through the forwarding tunnel, the handover request includes the QFI of the unicast QoS flow corresponding to the multicast / broadcast QoS flow.

[0223] S803. S-AMF selects a target AMF (target-AMF, T-AMF) based on the Target ID.

[0224] The T-AMF is connected to the T-gNB.

[0225] S804. The S-AMF sends a UE context creation request to the T-AMF.

[0226] The UE context creation request may be a Namf_Communication_CreateUEContext request. The request may include context information of the UE that has been handed over and stored in the S-AMF, and may further include information sent by the S-gNB to the S-AMF in step 802.

[0227] S805. The T-AMF sends a PDU session context update request to the SMF.

[0228] The PDU session context update request may be an Nsmf_PDU Session_UpdateSMContext request. The request message may include PDU session identification information (e.g., PDU session ID), T-AMF identification information (e.g., T-AMF ID), Target ID, N2 SM information, etc.

[0229] S806 to S808 correspond to the SMF sending message 01, message 02, and message 03 to UDR / UDM / PCF, respectively.

[0230] Message 01 may be for the SMF to query the UDR / UDM / PCF for context information of a first multicast / broadcast service. Message 02 may be for the SMF to query the UDR / UDM / PCF for context information of the first multicast / broadcast corresponding to location information corresponding to a Target ID. Message 03 may be for the SMF to query the UDR / UDM / PCF for context information of the first multicast / broadcast corresponding to location information corresponding to a target access network device.

[0231] It should be noted that the context information may include identification information of the multicast / broadcast service, such as, but not limited to, one or a combination of one or more of the following: a multicast / broadcast service identifier, a multicast / broadcast service name, a multicast / broadcast address of the multicast / broadcast service, a multicast / broadcast IP address of the multicast / broadcast service, a temporary mobile group identity (TMGI) corresponding to the multicast / broadcast service, and a session address of the multicast / broadcast service. The context information may further include service area information corresponding to the multicast / broadcast service, such as, one or more of the following information, or any combination of one or more of the following information: geographical area information, public land mobile network information, tracking area information, cell identification information, base station identification information, base station central unit identification information, base station distributed unit (DU) identification information, and civil address list. The context information may further include an area session identifier of the service area corresponding to the multicast / broadcast service.

[0232] S809.SMF determines that the terminal's reference location is within the service area of ​​the first multicast / broadcast service.

[0233] Specifically, if the SMF stores context information of a first multicast / broadcast service for a terminal on an S-gNB, the SMF determines that the identifier of the terminal's target cell and / or the identifier of the terminal's T-gNB are included in the service area of ​​the context information of the first multicast / broadcast service.

[0234] The S811.SMF sends a PDU Session Context Update Response to the T-AMF.

[0235] The PDU Session Context Update response may be an Nsmf_PDU Session_UpdateSMContext response.

[0236] If the SMF determines that the reference location of the terminal is within the service area of ​​the first multicast / broadcast service, the SMF sends a PDU session context update response to the T-AMF.

[0237] Specifically, the SMF may use the PDU Session Context Update Response to allocate transmission resources to the terminal or to inform the terminal to establish transmission resources.

[0238] The PDU session context update response message may include QoS information of unicast QoS flows of the PDU session, and the unicast QoS flow may include the unicast QoS flow to which the first multicast / broadcast QoS flow is mapped.

[0239] The QoS information may include a QFI and corresponding QoS parameters.

[0240] Optionally, if the SMF does not store context information of the first multicast / broadcast service for the terminal on the S-gNB, the SMF may send message 01 to the UDR / UDM / PCF to obtain context information of the first multicast / broadcast service.

[0241] S812. The T-AMF sends a handover request to the T-gNB.

[0242] The message includes QoS information of the unicast QoS flows included in the PDU session. In this case, the T-gNB allocates radio resources to the unicast QoS flows based on the QoS information of the unicast QoS flows.

[0243] It should be understood that for simplicity, other steps in Figures 8A and 8B are not described in detail, and these steps should be understood as prior art in N2 handover, and the details will not be described again.

[0244] According to the communication method for multicast / broadcast services provided in this application, when the SMF dynamically determines that the reference location information of the terminal is within the service area of ​​the first multicast / broadcast service, the T-gNB of the terminal is triggered to allocate resources to the terminal or establish resources for the terminal, thereby improving the utilization of network resources.

[0245] 22A and 22B, this embodiment provides a schematic flowchart of performing N2 handover for a terminal between non-co-site cells. In the embodiment shown in FIG. 22A and 22B, an example in which the network device is an SMF is used for explanation.

[0246] S2201. The UE sends a measurement report to the source base station (S-gNB).

[0247] In response, the S-gNB receives a measurement report. The measurement report may include signal measurements of up to eight neighboring cells measured by the UE. The S-gNB determines to hand over the UE to the T-gNB based on the measurement report. For example, the source base station selects the base station to which the neighboring cell with the strongest signal belongs as the T-gNB to which the UE will be handed over, i.e., the T-gNB is selected by the S-gNB for the UE. For a specific implementation of determining to hand over the UE to the T-gNB based on the measurement report, please refer to the description of the existing related art. Details will not be described again here.

[0248] S2202. The S-gNB sends a handover required to the S-AMF. S2202 differs from S802 in that the N2 session management information (N2 SM information) in the handover required includes the target cell identification information (target cell ID). For example, the N2 session management information may be a Handover Required Transfer. Alternatively, the target cell identification information is an information element parallel to the N2 session management information.

[0249] Specifically, after obtaining the identifier of the target cell, the S-gNB discovers / determines that the terminal device is subscribed to a first multicast / broadcast service, and the S-gNB sends a Handover Required to the S-AMF.

[0250] Additionally, the S-gNB may obtain the identifier of the target cell. For example, the S-gNB itself stores the identification information of a cell in another base station, e.g., the identifier of a cell included in a neighboring base station. Alternatively, the S-gNB obtains the identification information of a cell in another base station, e.g., the identifier of a cell included in a neighboring base station, based on operation, administration, and maintenance (OAM). Alternatively, the S-gNB obtains the identification information of a cell in another base station, e.g., the identifier of a cell included in a neighboring base station, based on a measurement report transmitted by the UE.

[0251] In a specific implementation, if the S-gNB discovers that the UE is subscribed to a multicast / broadcast service, which may be, for example, the first multicast / broadcast service, the Handover Required sent by the S-gNB to the S-AMF carries the target cell identification information (Target Cell ID). The target cell identification information is included in the N2 session management information (N2 SM information). The N2 session management information may be the Handover Required Transfer. The N2 session management information is an information element that is parallel to the Handover Type, Source to Target Transparent Container, Target ID, etc. Alternatively, the target cell identification information is an information element that is parallel to the N2 session management information. The information element parallel to the N2 session management information may be, for example, the identification information of the target cell that serves as an information element parallel to the information element included in the handover required in the prior art, i.e., handover type, target identifier, cause, source to target transparent container, PDU session resource list, message type, AMF UE NGAP ID, RAN UE NGAP ID, and RAN UE NGAP ID, in addition to the information elements included in the handover required in the prior art.In another example, the target cell identification information serves as an information element in addition to the information elements included in the handover required in the prior art, i.e., handover type, target identifier, cause, source to target transparent container, PDU session resource list, message type, AMF UE NGAP ID, and RAN UE NGAP ID, and is not carried in any of the information elements that must be included in the handover required in the prior art, but is carried in the handover required as an independent information element.

[0252] In one implementation, the S-gNB discovering whether the UE is subscribed to the multicast / broadcast service may include the following scheme:

[0253] In a first scheme, the S-gNB may determine whether the UE is subscribed to the first multicast / broadcast service based on whether the UE's context includes an identifier of the first multicast / broadcast service (e.g., an MBS Session ID or TMGI), or based on whether the UE's context includes an identifier of the first multicast / broadcast service (e.g., an MBS Session ID or TMGI) and an area session identifier (e.g., an area session ID or flow ID).

[0254] In the case of a non-local multicast / broadcast service, i.e., when the first multicast / broadcast service is a non-local multicast / broadcast service, if the UE context includes an identifier (e.g., MBS Session ID or TMGI) of the first multicast / broadcast service, it indicates that the UE is subscribed to the first multicast / broadcast service. Conversely, if the UE context does not include an identifier (e.g., MBS Session ID or TMGI) of the first multicast / broadcast service, it indicates that the UE is not participating in the first multicast / broadcast service.

[0255] In the case of a local multicast / broadcast service, i.e., when the first multicast / broadcast service is a local multicast / broadcast service, if the UE context includes an identifier of the first multicast / broadcast service (e.g., MBS Session ID or TMGI) and an area session identifier (e.g., Area Session ID or Flow ID), it indicates that the UE is subscribed to the first multicast / broadcast service. Conversely, if the UE context does not include an identifier of the first multicast / broadcast service (e.g., MBS Session ID or TMGI) and an area session identifier (e.g., Area Session ID or Flow ID), it indicates that the UE is not participating in the first multicast / broadcast service.

[0256] In a second scheme, the S-gNB may determine whether the UE is subscribed to the first multicast / broadcast service based on whether the context (MBS session context) corresponding to the first multicast / broadcast service includes a UE identity (e.g., a New Generation Application Protocol UE ID (NGAP UE ID), a Subscription Permanent Identifier (SUPI), a Generic Public Subscription Identifier (GPSI), or a Subscription Concealed Identifier (SUCI)). When the context corresponding to the first multicast / broadcast service includes the UE identity, it indicates that the UE is subscribed to the first multicast / broadcast service. Conversely, when the context corresponding to the first multicast / broadcast service does not include the UE identity, it indicates that the UE is not participating in the first multicast / broadcast service.

[0257] In a third scheme, the S-gNB may determine whether the UE is subscribed to the first multicast / broadcast service based on whether the UE's context includes an identifier of the first multicast / broadcast service (e.g., an MBS Session ID or TMGI), or the S-gNB may determine whether the UE is subscribed to the first multicast / broadcast service based on whether the UE's context includes an identifier of the first multicast / broadcast service (e.g., an MBS Session ID or TMGI) and an area session identifier (e.g., an area session ID or flow ID). Additionally, the S-gNB may determine whether the UE is subscribed to the first multicast / broadcast service based on whether the context (MBS Session Context) corresponding to the first multicast / broadcast service includes UE identification information (e.g., an NGAP UE ID, SUPI, GPSI, or SUCI).

[0258] In the case of a non-local multicast / broadcast service, i.e., when the first multicast / broadcast service is a non-local multicast / broadcast service, if the UE context includes an identifier of the first multicast / broadcast service (e.g., MBS Session ID or TMGI) and the context corresponding to the first multicast / broadcast service also includes UE identification information, it indicates that the UE is subscribed to the first multicast / broadcast service. Conversely, if the UE context does not include an identifier of the first multicast / broadcast service (e.g., MBS Session ID or TMGI) and the context corresponding to the first multicast / broadcast service also does not include UE identification information, it indicates that the UE is not participating in the first multicast / broadcast service.

[0259] In the case of a local multicast / broadcast service, i.e., when the first multicast / broadcast service is a local multicast / broadcast service, if the UE context includes an identifier (e.g., MBS Session ID or TMGI) and an area session identifier (e.g., Area Session ID or Flow ID) of the first multicast / broadcast service and the context corresponding to the first multicast / broadcast service also includes UE identification information, it indicates that the UE is subscribed to the first multicast / broadcast service. Conversely, if the UE context does not include an identifier (e.g., MBS Session ID or TMGI) and an area session identifier (e.g., Area Session ID or Flow ID) of the first multicast / broadcast service and the context corresponding to the first multicast / broadcast service also does not include UE identification information, it indicates that the UE is not participating in the first multicast / broadcast service.

[0260] Additionally, the S-gNB may further determine whether the UE subscribes to the first multicast / broadcast service in another manner, which is not limited in this application.

[0261] When the S-gNB determines whether a UE is subscribed to multiple multicast / broadcast services, for example, when the S-gNB determines whether a UE is subscribed to a first multicast / broadcast service and a second multicast / broadcast service, the S-gNB may use the three methods described above or other methods to determine whether the UE is subscribed to both the first multicast / broadcast service and the second multicast / broadcast service. Such a determination method is similar to the method for determining whether a UE is subscribed to the first multicast / broadcast service, and the details will not be described again here.

[0262] S2203 is the same as S802, and the details will not be described again here.

[0263] S2204. The S-AMF sends a create UE context request to the T-AMF. Unlike S804, the N2 session management information (N2 SM information) in the create UE context request sent by the S-AMF to the T-AMF further includes a target cell identifier (target cell ID), and the N2 session management information may be a handover required transfer. Alternatively, the target cell identifier is an information element parallel to the N2 session management information. The information element parallel to the N2 session management information has been described above, and the details will not be described again here.

[0264] S2205. The T-AMF sends a PDU session context update request to the SMF. Unlike S805, the N2 session management information (N2 SM information) in the PDU session context update request sent by the T-AMF to the SMF further includes a target cell identifier (target cell ID). The N2 session management information may be a handover required transfer. Alternatively, the target cell identifier is an information element parallel to the N2 session management information. The information element parallel to the N2 session management information has been described above and will not be described again in detail here.

[0265] If the SMF finds, based on the target cell identification information (target cell ID), that the target cell (target cell ID) is outside the service area of ​​the first multicast / broadcast service, the SMF may release a first transmission resource for the terminal. The first transmission resource is used to transmit data for the first multicast / broadcast service and includes resources used by the terminal to transmit data for the first multicast / broadcast service via the T-gNB of the terminal. Alternatively, if the SMF finds that the target cell (target cell ID) is outside the service area of ​​the first multicast / broadcast service, the SMF does not send QoS information corresponding to the first multicast / broadcast service to the target access network device. In other words, the N2 session management information (N2 SM information) sent by the SMF to the T-gNB does not include QoS information corresponding to the first multicast / broadcast service.

[0266] It should be noted that release may also be understood as triggering release, triggering or removing, initiating or terminating removal, etc.

[0267] If the SMF finds, based on the target cell identification information (target cell ID), that the UE's target cell (target cell ID) is within the service area of ​​the second multicast / broadcast service, the SMF may initiate establishment / configuration of second transmission resources for the terminal. The second transmission resources are used to transmit data for the second multicast / broadcast service and include resources used by the terminal to transmit data for the second multicast / broadcast service via the T-gNB. The description of the second transmission resources may be the same as the description of the first transmission resources, and the details will not be described again here. Alternatively, if the SMF finds that the target cell (target cell ID) is within the service area of ​​the second multicast / broadcast service, the SMF sends QoS information corresponding to the second multicast / broadcast service to the terminal's target access network device. In other words, the N2 session management information (N2 SM information) sent by the SMF to the terminal's target network device includes QoS information corresponding to the second multicast / broadcast service.

[0268] It should be noted that release may also be understood as triggering release, triggering or removing, initiating or terminating removal, etc.

[0269] The following steps S2206 to S2212 are the same as steps S806 to S812, and the details will not be explained again here.

[0270] 23A and 23B, this embodiment provides a schematic flowchart of performing N2 handover for a terminal between non-co-site cells. In the embodiment shown in FIG. 23A and 23B, an example in which the network device is an SMF is used for explanation.

[0271] S2301. The UE sends a measurement report to the source base station (S-gNB).

[0272] In response, the S-gNB receives a measurement report. The measurement report may include signal measurements of up to eight neighboring cells measured by the UE. The S-gNB determines to hand over the UE to the T-gNB based on the measurement report. For example, the S-gNB selects the base station to which the neighboring cell with the strongest signal belongs as the T-gNB to which the UE will be handed over, i.e., the T-gNB is selected by the S-gNB for the UE. For details on determining to hand over the UE to the T-gNB based on the measurement report, please refer to the description of the existing related art. Details will not be described again here.

[0273] If the S-gNB discovers that the UE is subscribed to a multicast / broadcast service, for example, a first multicast / broadcast service and / or a second multicast / broadcast service, and if the S-gNB discovers that the target cell identifier (target cell ID) is outside the service area of ​​the first multicast / broadcast service and / or within the service area of ​​the second multicast / broadcast service, the S-gNB includes indication information in the N2 session management information (N2 SM information) in the handover required sent to the S-AMF at S2302. The indication information includes first indication information and / or second indication information. The first indication information may inform the SMF that the target cell (target cell ID) is outside the service area of ​​the first multicast / broadcast service, and the second indication information may inform the SMF that the target cell (target cell ID) is within the service area of ​​the second multicast / broadcast service. The N2 session management information is a Handover Required Transfer.

[0274] Additionally, the handover required further includes an identifier of the first multicast / broadcast service and / or an identification of the second multicast / broadcast service.

[0275] S2302. The S-gNB sends a handover required to the S-AMF. S2302 differs from S802 in that the N2 session management information (N2 SM information) in the handover required further includes indication information, i.e., first indication information and / or second indication information. The N2 session management information may be Handover Required Transfer. Alternatively, the indication information is an information element parallel to the N2 session management information. The information element parallel to the N2 session management information has been described above, and the details will not be described again here.

[0276] In other words, it should be noted that when the S-gNB needs to notify the SMF that the target cell (target cell ID) is outside the service area of ​​the first multicast / broadcast service, it adds the first notification information to the N2 session management information (N2 SM information) in the handover required sent to the S-AMF at S2302. When the S-gNB needs to notify the SMF that the target cell (target cell ID) is within the service area of ​​the second multicast / broadcast service, it adds the second notification information to the N2 session management information (N2 SM information) in the handover required to the S-AMF at S2302. When the S-gNB needs to notify the SMF that the target cell (target cell ID) is outside the service area of ​​the first multicast / broadcast service and needs to notify the SMF that the target cell (target cell ID) is within the service area of ​​the second multicast / broadcast service, the S-gNB includes the first indication and / or the second indication in the N2 session management information (N2 SM information) of the handover required sent to the S-AMF at S2302. The indication may also function as a notification or notice. The N2 session management information may be Handover Required Transfer. Alternatively, the first indication and / or the second indication is an information element parallel to the N2 session management information. The information element parallel to the N2 session management information has been described above and will not be described again in detail here.

[0277] The first indication information may correspond to an identifier of a first multicast / broadcast service, and the second indication information may correspond to an identifier of a second multicast / broadcast service.

[0278] S2303 is the same as S802, and the details will not be explained again here.

[0279] S2304 differs from S804 in that the N2 session management information (N2 SM information) in the Create UE Context Request sent by the S-AMF to the T-AMF includes indication information, and the indication information includes first indication information and / or second indication information. The N2 session management information may be Handover Required Transfer. Alternatively, the first indication information and / or the second indication information are information elements parallel to the N2 session management information. The information elements parallel to the N2 session management information have been described above, and the details will not be described again here.

[0280] S2305 differs from S805 in that the N2 session management information (N2 SM information) in the PDU session context update request sent by the T-AMF to the SMF further includes indication information, which is first indication information and / or second indication information. The N2 session management information may be Handover Required Transfer. Alternatively, the first indication information and / or the second indication information is an information element parallel to the N2 session management information. The information element parallel to the N2 session management information has been described above and will not be described again in detail here.

[0281] If the SMF discovers based on the first indication information and / or the second indication information that the target cell (target cell ID) is outside the service area of ​​the first multicast / broadcast service, the SMF may release a first transmission resource of the terminal. The first transmission resource is used to transmit data of the first multicast / broadcast service and includes resources used by the terminal to transmit data of the first multicast / broadcast service via the T-gNB of the terminal. Alternatively, if the SMF discovers that the target cell (target cell ID) is outside the service area of ​​the first multicast / broadcast service, the SMF does not transmit QoS information corresponding to the first multicast / broadcast service to the target access network device of the terminal. In other words, the N2 session management information (N2 SM information) transmitted by the SMF to the T-gNB does not include QoS information corresponding to the first multicast / broadcast service.

[0282] If the SMF discovers, based on the first indication information and / or the second indication information, that the target cell (target cell ID) is within the service area of ​​the second multicast / broadcast service, the SMF may initiate establishment / configuration of second transmission resources for the terminal. The second transmission resources are used to transmit data for the second multicast / broadcast service and include resources used by the terminal to transmit data for the second multicast / broadcast service via the T-gNB of the terminal. The description of the second transmission resources may be the same as the description of the first transmission resources, and the details will not be described again here. Alternatively, if the SMF discovers that the target cell (target cell ID) is within the service area of ​​the second multicast / broadcast service, the SMF transmits QoS information corresponding to the second multicast / broadcast service to the target access network device of the terminal. In other words, the N2 session management information (N2 SM information) transmitted by the SMF to the T-gNB includes QoS information corresponding to the second multicast / broadcast service.

[0283] The following steps S2306 to S2312 are the same as steps S806 to S812, and the details will not be explained again here.

[0284] As shown in Figure 9, this embodiment provides a schematic flowchart of performing Xn handover for a terminal between non-co-site cells. In the embodiment shown in Figure 9, an example in which the network device is an SMF is used for explanation.

[0285] S901 to S905 are handover of a terminal from an S-gNB to a T-gNB in ​​the Xn handover procedure in the prior art. For simplicity, the details are not described here in this application.

[0286] S906. The T-gNB sends an N2 path switch request to the AMF.

[0287] For example, the request may include the QFIs of the unicast QoS flows that were successfully switched and the QFIs of the unicast QoS flows that were unsuccessfully switched in the UE's PDU session, and / or the QFIs of the multicast / broadcast QoS flows that were successfully switched and the QFIs of the multicast / broadcast QoS flows that were unsuccessfully switched in the PDU session. For example, these QFIs may be encapsulated in an N2 SM message. Additionally, the N2 path switch request may further include an endpoint identifier of a PDU session tunnel allocated to the UE by the T-gNB. Alternatively, the N2 path switch request may further include UE location information, etc. The UE location information may be the terminal's location information in a target access network device and may include identification information of a target cell, etc.

[0288] S907.AMF sends a PDU session context update request to the SMF.

[0289] The PDU session context update request may be an Nsmf_PDU Session_UpdateSMContext request.

[0290] Specifically, it can be seen from Figure 9 that when the AMF sends an Update PDU Session Context Request to the SMF, the handover of the UE from the S-gNB to the T-gNB, i.e., steps 901 to 905, has been completed. Therefore, the Update PDU Session Context Request carries the location information of the UE at the current T-gNB.

[0291] The S911.SMF determines that the terminal's reference location is within the service area of ​​the first multicast / broadcast service. Specifically, the SMF determines that the UE's location information is included in the multicast / broadcast context information based on the UE's location information and the multicast / broadcast context information corresponding to the first multicast / broadcast service to which the UE subscribes on the S-gNB. For example, the SMF may determine that the area identification information in the multicast / broadcast context information includes the identification information of the target cell.

[0292] S912.SMF sends an N4 session update / modify request to PSA (UPF).

[0293] Specifically, when the SMF determines that the multicast / broadcast context information contains the UE's location information, it notifies the UPF to establish the first transmission resource using an N4 Session Update / Modify Request.

[0294] It should be understood that for simplicity, the other steps in Figure 9 are not described in detail, and these steps should be understood as prior art in Xn handover, and the details will not be described again.

[0295] According to the communication method for multicast / broadcast services provided in this application, when the SMF dynamically determines that the reference location information of the terminal is within the service area of ​​the first multicast / broadcast service, the PSA (UPF) is triggered to allocate resources to the terminal or establish resources for the terminal, thereby improving the utilization of network resources.

[0296] Next, an explanation is provided using an example where the network device is an S-gNB.

[0297] 10A and 10B, this embodiment provides a schematic flowchart of performing N2 handover for a terminal between non-co-site cells. In the embodiment shown in FIG. 10A and 10B, an example in which the network device is an S-gNB is used for explanation.

[0298] S1001. The UE sends a measurement report to the S-gNB.

[0299] S1002. The S-gNB determines that the reference location of the terminal is within the service area of ​​the first multicast / broadcast service.

[0300] Specifically, after receiving a measurement report from the UE, the S-gNB determines to handover the UE to the T-gNB based on the measurement report, where the measurement report carries the identity of the T-gNB and / or the identity of the target cell.

[0301] The S-gNB stores service area information in context information corresponding to the first multicast / broadcast service to which the UE subscribes at the source base station, and thus determines that the identity of the T-gNB or the identity of the target cell in the measurement report is included in the service area of ​​the first multicast / broadcast service.

[0302] S1003. The S-gNB sends a Handover Required to the S-AMF.

[0303] Specifically, when the S-gNB determines that the identification information of the T-gNB or the identification information of the target cell in the measurement report is included in the service area of ​​the first multicast / broadcast service, the S-gNB sends a Handover Required to the S-AMF. The Handover Required may include PDU session information of the multicast / broadcast service associated with the UE to be handed over. In other words, the PDU session information includes information about the unicast QoS flow to which the multicast / broadcast QoS flow is mapped. Additionally, the Handover Required further includes the identification information of the target cell to which the UE is handed over.

[0304] In S1004 to S1013, the PDU session information is transmitted to the T-gNB, and after receiving the information, the T-gNB allocates transmission resources to the UE to be used for transmitting data of the first multicast / broadcast service.

[0305] Specifically, the T-gNB assigns a corresponding radio bearer to a multicast / broadcast QoS flow based on information about the unicast QoS flow to which the multicast / broadcast QoS flow is mapped. In other words, the relationship configuration from the PDCP layer to the PHY layer is to satisfy the QoS parameter requirements. The requirements may be, for example, bandwidth, delay, or jitter.

[0306] It should be understood that other steps in Figures 10A and 10B are not described in detail, and these steps should be understood as prior art in N2 handover, and the details will not be described again.

[0307] According to the communication method for multicast / broadcast services provided in this application, during an N2 handover procedure, when an S-gNB dynamically determines that the reference location information of a terminal is within the service area of ​​a first multicast / broadcast service, a T-gNB of the terminal is triggered to allocate resources to the terminal or establish resources for the terminal, thereby improving the utilization of network resources.

[0308] As shown in Figure 11, this embodiment provides a schematic flowchart of performing Xn handover for a terminal between non-co-site cells. In the embodiment shown in Figure 11, an example in which the network device is an S-gNB is used for explanation.

[0309] S1101. The UE sends a measurement report to the S-gNB.

[0310] S1102. The S-gNB determines that the reference location of the terminal is within the service area of ​​the first multicast / broadcast service.

[0311] Specifically, after receiving a measurement report from the UE, the S-gNB determines to handover the UE to the T-gNB based on the measurement report, where the measurement report carries the identity of the T-gNB and / or the identity of the target cell.

[0312] The S-gNB stores service area information in context information corresponding to the first multicast / broadcast service to which the UE subscribes at the source base station, and thus determines that the identity of the T-gNB or the identity of the target cell in the measurement report is included in the service area of ​​the first multicast / broadcast service.

[0313] S1103. The S-gNB sends a handover request to the T-gNB.

[0314] Specifically, when the S-gNB determines that the T-gNB's identification information or the target cell's identification information in the measurement report is included in the service area of ​​the first multicast / broadcast service, it sends a handover request to the T-gNB. The handover request may include PDU session information of the multicast / broadcast service associated with the UE to be handed over. In other words, the PDU session information includes information about the unicast QoS flow to which the multicast / broadcast QoS flow is mapped. Additionally, the handover request further includes the identification information of the target cell to which the UE is handed over.

[0315] S1104. The T-gNB sends a handover request response to the S-gNB.

[0316] Specifically, after receiving the handover request at S1103, the T-gNB allocates transmission resources to the UE to be used for transmitting data of the first multicast / broadcast service based on the PDU session information.

[0317] The context information in the preceding descriptions (FIGS. 7 to 11) may include multicast / broadcast service identification information, such as, but not limited to, one or a combination of, a multicast / broadcast service identifier, a multicast / broadcast service name, a multicast / broadcast address of the multicast / broadcast service, a multicast / broadcast IP address of the multicast / broadcast service, a temporary mobile group identity (TMGI) corresponding to the multicast / broadcast service, and a session address of the multicast / broadcast service. The context information may further include service area information corresponding to the multicast / broadcast service, such as, one or a combination of, geographical area information, public land mobile network information, tracking area information, cell identification information, base station identification information, base station central unit identification information, base station distributed unit (DU) identification information, and civil address list information. The context information may further include an area session identifier of the service area corresponding to the multicast / broadcast service.

[0318] It should be understood that the other steps in Figure 11 are not described in detail, and these steps should be understood as the prior art in Xn handover, and the details will not be described again.

[0319] According to the communication method for multicast / broadcast services provided in this application, during an Xn handover procedure, when an S-gNB dynamically determines that the reference location information of a terminal is within the service area of ​​a first multicast / broadcast service, a T-gNB of the terminal is triggered to allocate resources to the terminal or establish resources for the terminal, thereby improving the utilization of network resources.

[0320] 12 is a schematic flowchart of a communication method 1200 for multicast / broadcast services according to one embodiment of the present application. The method may be applied to a process in which a terminal is handed over from an S-gNB to a T-gNB device, or may be applied to a process in which a terminal is handed over between co-site cells. The method 1200 includes at least the following steps:

[0321] S1201. A network device obtains reference location information of a terminal.

[0322] The reference location information represents a reference location of the terminal. The reference location information includes the terminal's location information in the access network device currently serving the terminal or the terminal's location information in the T-gNB of the terminal. Note that the location information includes at least one of a cell identifier, an access network device identifier, a tracking area identifier, and a public land mobile network (PLMN) identifier. Additionally, the location information may include global positioning system (GPS) geographic location information, a sector identifier, a PCI, an antenna identifier, a DU identifier, etc.

[0323] Optionally, when the reference location information includes location information of the terminal in an access network device currently serving the terminal, the location information may be a combination of one or more of an identifier of a current serving cell, an identifier of an access network currently serving the terminal, an identifier of a current tracking area, etc.

[0324] Optionally, when the reference location information includes location information of the terminal at the T-gNB of the terminal, the location information may be one or more of a target cell identifier, a T-gNB identifier, a target tracking area identifier, etc.

[0325] S1202. The network device initiates release of first transmission resources of the terminal, the first transmission resources being used to transmit data of the first multicast / broadcast service, including resources used by the terminal to transmit data of the first multicast / broadcast service via the T-gNB of the terminal.

[0326] Specifically, when the network device determines that the reference location of the terminal is outside a service area of ​​the first multicast / broadcast service, the network device triggers the release of a first transmission resource of the terminal, the first transmission resource being used to transmit data of the first multicast / broadcast service.

[0327] It should be noted that release may also be understood as triggering release, triggering deletion, initiating deletion, etc.

[0328] According to the communication method for multicast / broadcast services provided in this application, when a network device determines that a terminal's reference location is outside the service area of ​​a first multicast / broadcast service, the network device triggers the release of transmission resources used to transmit data of the first multicast / broadcast service. Through the processes and operations performed by the network device, this solution can effectively save network resources and avoid resource waste caused by invalid transmission of data of the multicast / broadcast service.

[0329] Optionally, the network device may be an SMF or an S-gNB.

[0330] First, the method 1200 will be described using an example in which the network device is an SMF. Specifically, the method may include an embodiment in which the network device is an SMF as shown in Figures 13-15.

[0331] As shown in FIG. 13, this embodiment provides a schematic flowchart of a co-site cell handover performed on a terminal.

[0332] S1301. An access network device reports location information to an AMF.

[0333] Specifically, the reference location information may be location information of the access network device currently serving the terminal. The access network device reports the location information to the AMF. The location information may be identification information of the cell in which the terminal is currently located.

[0334] S1302.SMF determines that the current access network device does not support the first multicast / broadcast service.

[0335] S1303.SMF subscribes to terminal location information from AMF.

[0336] Optionally, if the SMF receives a join request from a terminal and determines that the current access network device does not support multicast / broadcast functionality, the SMF subscribes to the terminal's location information from the AFM. It is to be understood that the join request may be a control plane signaling, for example, a PDU session modification / establishment request, or the join request may be a user plane join request, for example, an Internet group management protocol join (IGMP join), multicast listener discovery (MLD), or multicast listener report (MLR).

[0337] Optionally, if the current access network device does not support multicast / broadcast functionality and the SMF determines that the service area established on the access network device for multicast / broadcast services includes one or more or all cells of the access network device, the SMF subscribes to terminal location information from the AMF.

[0338] Optionally, if the SMF determines that the current access network device does not support multicast / broadcast functionality, the SMF subscribes to terminal location information from the AFM.

[0339] Alternatively, when the SMF receives a multicast / broadcast service establishment indication sent by the MB-SMF, the SMF subscribes to the terminal location information from the AMF.

[0340] In another possible scheme, when the SMF receives a multicast / broadcast service establishment / modification instruction sent by the UDR or PCF, the SMF subscribes to the terminal location information from the AMF.

[0341] Alternatively, when the SMF receives a PDU session modification / establishment request sent from the UDR, PCF, or UDM, the SMF subscribes to the terminal location information from the AMF.

[0342] Triggering the SMF to subscribe to the terminal's location information from the AMF described above is by way of example and not limitation, and it should be understood that this may be triggered when the terminal moves, when the terminal accesses a multicast / broadcast service, or by other conditions.

[0343] S1304.AMF reports the location information of the terminal to SMF.

[0344] Specifically, after receiving the subscription message, the AMF may return a first message to the SMF, which carries the terminal's location information.

[0345] S1305.SMF initiates the release of the first transmission resource of the terminal.

[0346] Specifically, based on the current location information of the UE, in the case of an access network device that does not support multicast / broadcast functionality, or after the UE moves out of the multicast / broadcast service area, the QoS flow corresponding to the multicast / broadcast service is released in the PDU session accorded to the multicast / broadcast service.

[0347] It will be appreciated that releasing a QoS flow corresponding to a multicast / broadcast service may also be understood as deleting the QoS flow corresponding to the multicast / broadcast service.

[0348] According to the communication method for multicast / broadcast services provided in this application, when a network device determines that the reference location of a terminal is outside the service area of ​​a first multicast / broadcast service, the network device triggers / initiates the release / deletion of a first transmission resource of the terminal, thereby effectively saving network resources and avoiding resource waste caused by invalid transmissions.

[0349] As shown in FIGS. 14A and 14B, this embodiment provides a schematic flowchart of performing N2 handover for a terminal between non-co-site cells.

[0350] It should be noted that a PDU session associated with a multicast / broadcast service may also be called a unicast fall-back PDU session, a 5GC shared delivery method to individual delivery method switch PDU session, a PDU session corresponding to the 5GC individual MBS traffic delivery method, a PDU session corresponding to the 5GC individual delivery method, or a PDU session corresponding to the individual delivery method.

[0351] The PDU session context update request may be an Nsmf_PDU Session_UpdateSMContext request.

[0352] Specifically, the PDU session context update request may include PDU session identification information, T-AMF identification information, target cell identification information (Target ID) selected by the source base station for the UE to be handed over, and N2 SM information (N2 SM information).

[0353] S1409.SMF determines that the terminal's reference location is outside the service area of ​​the first multicast / broadcast service.

[0354] The reference location may be the terminal's location information at the terminal's T-gNB, and the location information may be a target cell identifier (Target ID), a T-gNB identifier, a target tracking area identifier, etc.

[0355] It should be understood that the location information is sent by the T-AMF to the SMF at S1405.

[0356] When a UE subscribes to a multicast / broadcast service, the SMF learns that a PDU session is associated with the multicast / broadcast service. Therefore, the SMF determines that the terminal's reference location is outside the service area of ​​the first multicast / broadcast service when one or more of the following conditions are met:

[0357] It should be noted that in the following, the decision conditions are briefly described in a differentiated manner based on whether a first multicast / broadcast service is established on the T-gNB or whether the location area corresponding to the target cell identification information is within the service area of ​​the multicast / broadcast service established by the T-gNB.

[0358] The multicast / broadcast service is not established (or does not exist, distributed, or start up) on the T-gNB, or the multicast / broadcast service is established on the T-gNB, but the terminal's location information on the T-gNB is not within the service area of ​​the multicast / broadcast service established on the T-gNB.

[0359] The foregoing not being established may also be understood as not existing, not being distributed, or not being started.

[0360] Optionally, the SMF does not store multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal is subscribed on the S-gNB. In this case, the SMF sends a first message to the UDR / UDM / PCF. The first message is to query the multicast / broadcast context information (or multicast / broadcast session context, multicast / broadcast service context, or multicast / broadcast group context) corresponding to the multicast / broadcast service (or session or group) to which the terminal is subscribed on the S-gNB (i.e., multicast / broadcast service, multicast / broadcast session, or multicast / broadcast group). The UDR / UDM / PCF returns the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal is subscribed on the S-gNB. The SMF determines that the terminal's location information at the T-gNB is not within the service area in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0361] The first message may include identification information corresponding to the multicast / broadcast service, and may further include an area session ID (also called a local area ID, multicast / broadcast session ID, or flow ID) of a service area corresponding to the multicast / broadcast service.

[0362] The context may include identification information of the multicast / broadcast service, which may be at least one of identification information such as an ID of the multicast / broadcast service, a name of the multicast / broadcast service, a multicast (or multicast) / broadcast address of the multicast / broadcast service, a multicast (or multicast) / broadcast IP address of the multicast / broadcast service, a TMGI corresponding to the multicast / broadcast service, and a session ID of the multicast / broadcast service (multicast / broadcast service session ID, MBS session ID). The context may further include information about a service area corresponding to the multicast / broadcast service, which may refer to, for example, information about a geographic area (i.e., information about one or more geographic areas), or may refer to at least one of a PLMN (which may refer to one or more PLMNs), a TAI (which may refer to one or more TAIs), a base station identity (which may refer to, but is not limited to, one or more identities), a cell identity (which may refer to one or more cell identities), a tracking area identity (which may refer to one or more tracking area identities), a location criteria of a central unit (CU) of the base station, and a distributed unit (DU) of the base station, or may be a civil address list, etc. The context may further include an area session identifier of the service area corresponding to the multicast / broadcast service.The area session identifier of the service area corresponding to the multicast / broadcast service may be the area session ID of the service area corresponding to the multicast / broadcast service, or may be called a local area ID, a local multicast / broadcast session ID, a local flow ID, etc.

[0363] Optionally, the SMF stores multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB, and the SMF determines that the terminal's location information at the T-gNB of the terminal is not within the service area of ​​the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0364] Optionally, the SMF may send a second message to the UDR / UDM / PCF and use the second message to query multicast / broadcast context information corresponding to the terminal's location information at the T-gNB. The UDR / UDM / PCF returns multicast / broadcast context information corresponding to the terminal's location information at the T-gNB. The SMF determines that the area session identifier in the multicast / broadcast context information corresponding to the terminal's location information at the T-gNB is different from the area session identifier in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0365] Optionally, the SMF determines that the terminal's location information at the T-gNB is only within the service area of ​​the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0366] Optionally, the SMF determines that the terminal location information at the T-gNB of the terminal is only within the service area in the multicast / broadcast context information corresponding to the terminal location information at the T-gNB of the terminal.

[0367] Optionally, the SMF determines that the area session identifier in the multicast / broadcast context information corresponding to the terminal's location information at the T-gNB is different from the area session identifier in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB and is further different from the area session identifier in the multicast / broadcast context information corresponding to the multicast / broadcast service of the T-gNB. The SMF may send a third message to the UDR / UDM / PCF and use the third message to query the multicast / broadcast context information corresponding to the identity of the T-gNB.

[0368] The multicast / broadcast service is established on the T-gNB, and the terminal's location information at the T-gNB is within the service area of ​​the multicast / broadcast service. In other words, the terminal's location information at the T-gNB is included in the service area of ​​the corresponding context information established by the T-gNB for the multicast / broadcast service.

[0369] Optionally, the SMF determines that the terminal's location information at the T-gNB is not within the service area in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0370] Optionally, the SMF determines that the service area of ​​the context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB is different from the service area of ​​the context information corresponding to the multicast / broadcast service obtained when or after the multicast / broadcast service is established on the T-gNB.

[0371] Optionally, the SMF determines that the area session identifier in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB is different from the area session identifier in the context information corresponding to the T-gNB during or after the multicast / broadcast service is established on the T-gNB.

[0372] Optionally, the SMF determines that the location area corresponding to the terminal location information at the T-gNB of the terminal is not within the service area in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0373] It should be understood that the above-mentioned determination conditions are examples and are not limiting. Any conditions that may be used to determine that the terminal's location information in the T-gNB is outside the service area of ​​the first multicast / broadcast / broadcast service should be included in the scope of protection of this application. Additionally, one or more of the above-mentioned conditions may also be combined for combined determination, which is not limited in this application.

[0374] S1411.SMF sends a PDU Session Context Update Response message to T-AMF.

[0375] Specifically, when the SMF determines, due to a condition, that the location information of the terminal's T-gNB terminal is not within the service area of ​​the first multicast / broadcast service, the SMF initiates the release of the terminal's first transmission resource.

[0376] Optionally, the QoS information of the unicast QoS flow of the PDU session in the PDU Session Context Update Response message sent by the SMF to the T-AMF does not include information about the unicast QoS flow to which the first multicast / broadcast QoS flow is mapped. In other words, when the SMF determines that the T-gNB is not in the service area of ​​the first multicast / broadcast service, the SMF does not create a QoS flow corresponding to the first multicast / broadcast service, but does not notify the T-gNB to configure / prepare / establish radio resources corresponding to the QoS flow corresponding to the first multicast / broadcast service.

[0377] Optionally, the SMF may notify the T-gNB of the terminal via the T-AMF that the first transmission resource is invalid.

[0378] Optionally, the SMF may notify the T-gNB of the terminal via the T-AMF not to establish / prepare radio resources corresponding to the first transmission resource.

[0379] Optionally, the SMF may not send the identifier of the first transmission resource to the T-gNB of the terminal via the T-AMF. Specifically, the access network device allocates air interface resources based on the QoS parameters corresponding to the QFI, i.e., maps the QFI to a data radio bearer (DRB), so the data radio bearer identified by the DRB identifier corresponds to the entire set of air interface resource configurations. Therefore, the session management function network element does not send the QFI identifier to the base station, and therefore the T-gNB does not allocate a DRB to the QFI.

[0380] The SMF initiates the release of the first transmission resource of the terminal.

[0381] (1) If a PDU session associated with a multicast / broadcast service includes only a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the SMF notifying the T-gNB of the terminal to release the first transmission resource may include one or more of the following actions:

[0382] Optionally, the SMF may not forward PDU sessions associated with multicast / broadcast services (or the SMF may disable the forwarding of PDU sessions associated with multicast / broadcast services). For example, based on the hierarchical structure formed by the handover request information element defined in 3GPP TS 38.413, the SMF may perform corresponding operations for the data transfer impossible information element.

[0383] Optionally, the SMF does not include the mapped unicast QoS flow in the QoS flow list that requires the establishment of the associated air interface on the T-gNB, e.g., the SMF does not include a QoS flow setup request item corresponding to the mapped unicast QoS flow in the QoS flow setup request list.

[0384] Optionally, the SMF includes a QoS flow setup request item corresponding to the mapped unicast QoS flow in the QoS flow setup request list, but the SMF does not perform parameter padding for the QoS flow identifier and the QoS flow level QoS parameters. Alternatively, the SMF does not perform parameter padding for the QoS flow identifier, the QoS flow level QoS parameters, and the E-RAB ID. Alternatively, the SMF does not perform parameter padding for the QoS flow identifier. Alternatively, the SMF does not perform parameter padding for the QoS flow level QoS parameters. Alternatively, the SMF does not perform parameter padding for the E-RAB ID, etc.

[0385] It should be understood that parameter padding may be, for example, actual parameters corresponding to format parameters, actual parameters corresponding to variables, actual values ​​corresponding to information elements, or values ​​corresponding to fields.

[0386] (2) If the PDU session associated with the multicast / broadcast service further includes another unicast QoS flow in addition to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, the SMF notifies the T-gNB of the terminal to release the first transmission resource. It is also applicable that the SMF initiates the release of the first transmission resource of the terminal. One or more of the following operations may further be included:

[0387] Optionally, the SMF does not include the mapped unicast QoS flow in the QoS flow list that requires the establishment of the associated air interface on the T-gNB, e.g., the SMF does not include a QoS flow setup request item corresponding to the mapped unicast QoS flow in the QoS flow setup request list.

[0388] Optionally, the SMF includes a QoS flow setup request item corresponding to the mapped unicast QoS flow in the QoS flow setup request list, but the SMF does not perform parameter padding for the QoS flow identifier and the QoS flow level QoS parameters. Alternatively, the SMF does not perform parameter padding for the QoS flow identifier, the QoS flow level QoS parameters, and the E-RAB ID. Alternatively, the SMF does not perform parameter padding for the QoS flow identifier. Alternatively, the SMF does not perform parameter padding for the QoS flow level QoS parameters. Alternatively, the SMF does not perform parameter padding for the E-RAB identifier, etc.

[0389] It should be understood that parameter padding may be, for example, actual parameters corresponding to format parameters, actual parameters corresponding to variables, actual values ​​corresponding to information elements, or values ​​corresponding to fields.

[0390] It should be noted that a PDU session associated with a multicast / broadcast service may also be called a unicast fall-back PDU session, a 5GC shared delivery method to individual delivery method switch PDU session, a PDU session corresponding to the 5GC individual MBS traffic delivery method, a PDU session corresponding to the 5GC individual delivery method, or a PDU session corresponding to the individual delivery method.

[0391] It should be understood that the above-mentioned determination conditions are examples and not limitations. Any conditions that may be used to determine that the reference location information of the terminal is outside the service area of ​​the first multicast / broadcast / broadcast service should be included in the scope of protection of this application. Additionally, one or more of the above-mentioned conditions may also be combined for joint determination, which is not limited in this application.

[0392] It should be understood that other steps in Figures 14A and 14B are not described in detail, and these steps should be understood as prior art in N2 handover, and the details will not be described again.

[0393] According to the communication method for multicast / broadcast services provided in this application, when the SME determines that the reference location of the terminal is outside the service area of ​​the first multicast / broadcast service, the SME notifies the target access network device of the terminal to initiate release of the first transmission resource of the terminal, thereby effectively saving network resources and avoiding resource waste caused by invalid forwarding.

[0394] As shown in Figure 15, this embodiment provides a schematic flowchart of performing Xn handover for a terminal between non-co-site cells. In the Xn handover process shown in Figure 15, the SMF obtains the location information (UE Location Information) of the access network device currently serving the terminal. In other words, in this case, the access network device serving the terminal is the target access network device, and the SMF notifies the UPF to release the first transmission resource.

[0395] Specifically, the following steps are included:

[0396] S1507. The AMF sends a PDU session context update request to the SMF.

[0397] The PDU Session Context Update Request includes reference location information of the UE (e.g., UE Location Information). The reference location information may be location information in the access network device currently serving the UE. The location information may be one or more of a current serving cell identifier, a current serving access network device identifier, a current tracking area identifier, etc.

[0398] The S1511.SMF determines that the terminal's reference location information is outside the service area of ​​the first multicast / broadcast service.

[0399] Specifically, the SMF determines that the terminal is outside the service area of ​​the first multicast / broadcast service based on information about the service area of ​​the first multicast / broadcast service in the context corresponding to the first multicast / broadcast service and the reference location information.

[0400] The following describes in detail how the SMF determines that the terminal's reference location is outside the service area of ​​the first multicast / broadcast service.

[0401] It should be noted that in the following, the decision conditions are briefly described in a differentiated manner based on whether the first multicast / broadcast service is established on the T-gNB or whether the UE's reference location information (e.g., UE Location Information) is within the service area of ​​the multicast / broadcast service established by the T-gNB.

[0402] The multicast / broadcast service is not established on the T-gNB, or the multicast / broadcast service is established on the T-gNB, but the terminal location information (e.g., UE Location Information) of the access network device currently serving the terminal is not within the service area of ​​the multicast / broadcast service established on the T-gNB.

[0403] Optionally, the SMF does not store multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB. In this case, the SMF sends a first message to the UDR / UDM / PCF. The first message is to query the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB. The UDR / UDM / PCF returns the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB. The SMF determines that the location information of the terminal in the access network device currently serving the terminal is not within the service area in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0404] Optionally, the SMF stores multicast / broadcast context information corresponding to a multicast / broadcast service to which the terminal subscribes on the S-gNB, and the SMF determines that the location information of the terminal in the access network device currently serving the terminal is not within the service area of ​​the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0405] Optionally, the SMF may send a second message to the UDR / UDM / PCF and use the second message to query multicast / broadcast context information corresponding to the terminal's location information in the access network device currently serving the terminal. The UDR / UDM / PCF returns the multicast / broadcast context information corresponding to the terminal's location information in the access network device currently serving the terminal. The SMF determines that the area session identifier in the multicast / broadcast context information corresponding to the terminal's location information in the access network device currently serving the terminal is different from the area session identifier in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0406] Optionally, the SMF determines that the location information of the terminal in the access network device currently serving the terminal is only within the service area in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal has subscribed on the S-gNB.

[0407] Optionally, the SMF determines that the terminal's location information in the access network device currently serving the terminal is only within the service area in the multicast / broadcast context information corresponding to the terminal's location information in the T-gNB for the terminal.

[0408] Optionally, the SMF determines that the area session identifier in the multicast / broadcast context information corresponding to the terminal's location information in the access network device currently serving the terminal is different from the area session identifier in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB and is further different from the area session identifier in the multicast / broadcast context information corresponding to the multicast / broadcast service of the T-gNB. The SMF may send a third message to the UDR / UDM / PCF and use the third message to query the multicast / broadcast context information corresponding to the identity of the T-gNB.

[0409] A multicast / broadcast service is established on the T-gNB, and the location information of the terminal in the access network device currently serving the terminal is within the service area of ​​the multicast / broadcast service established on the T-gNB. In other words, the location information of the terminal in the access network device currently serving the terminal is included in the service area of ​​the corresponding context information established by the T-gNB for the multicast / broadcast / broadcast service.

[0410] Optionally, the SMF determines that the location information of the terminal in the access network device currently serving the terminal is not within the service area in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal has subscribed on the S-gNB.

[0411] Optionally, the SMF determines that the service area of ​​the context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB is different from the service area of ​​the context information corresponding to the multicast / broadcast service obtained when or after the multicast / broadcast service is established on the T-gNB.

[0412] Optionally, the SMF determines that the service area of ​​the context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB is different from the service area of ​​the context information corresponding to the multicast / broadcast service obtained when or after the multicast / broadcast service is established on the T-gNB.

[0413] Optionally, the SMF determines that the area session identifier in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB is different from the area session identifier in the context information corresponding to the T-gNB during or after the multicast / broadcast service is established on the T-gNB.

[0414] Optionally, the SMF determines that the location area corresponding to the terminal's location information in the access network device currently serving the terminal is not within the service area in the multicast / broadcast context information corresponding to the multicast / broadcast service to which the terminal subscribes on the S-gNB.

[0415] It should be understood that the above-mentioned determination conditions are examples and not limitations. Any conditions that may be used to determine that the location information of the terminal in the access network device currently serving the terminal is outside the service area of ​​the first multicast / broadcast / broadcast service should be included in the scope of protection of this application. Additionally, one or more of the above-mentioned conditions may also be combined for joint determination, which is not limited in this application.

[0416] S1512.SMF sends an N4 session update / modify request to UPF.

[0417] Specifically, the SMF sends an N4 session update / modification request to the UPF, which includes an indication to notify the UPF to release the first transmission resource.

[0418] In conclusion, in the Xn handover procedure, when the SMF determines that the terminal's location information in the terminal's current access network device (i.e., the location information in the target base station, i.e., the UE location information provided in S1507) is not within the service area of ​​the first multicast / broadcast service, the SMF notifies the UPF to release / delete / disable the first transmission resource by sending an N4 Session Update / Modify Request or a PFCP Session Update / Modify Request to the UPF. The N4 Session Update / Modify Request does not include a PDR corresponding to the QoS flow of the first multicast / broadcast service, and may not include one or more of FAR, QER, or URR.

[0419] Specifically, the SMF notifying the UPF to release the first transmission resource by sending an N4 Session Update / Modify request or a PFCP Session Update / Modify request to the UPF may include one or more of the following operations:

[0420] (1) If a PDU session associated with a multicast / broadcast service includes another unicast QoS flow in addition to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, a hierarchical structure is formed based on the path switch request forwarding information element defined in 3GPP TS 29.502 and 38.413. Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" includes the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, the SMF deletes (or releases or sets to null) the entry corresponding to the multicast / broadcast QoS flow from the "QoS Flow Allow List".

[0421] Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" contains a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the SMF sets the parameter included in the item corresponding to the multicast / broadcast QoS flow, i.e., the "QoS Flow Identifier", to null.

[0422] Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" includes a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the SMF does not establish, add, modify, or update the PDR(s), PDR(s), FAR(s), etc. corresponding to the multicast / broadcast QoS flow or does not provide the PDR(s), FAR(s), etc. corresponding to the multicast / broadcast QoS flow to the PSA-UPF / UPF when establishing, adding, modifying, or updating the PFCP session context.

[0423] Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" includes a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the SMF shall not establish, add, modify, or update the PDR(s) etc. corresponding to the multicast / broadcast QoS flow or shall not provide the PDR(s) etc. corresponding to the multicast / broadcast QoS flow to the PSA-UPF / UPF when establishing, adding, modifying, or updating the PFCP session context.

[0424] Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" includes a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the SMF shall not establish, add, modify or update the FAR(s), QER(s), etc. corresponding to the multicast / broadcast QoS flow, or provide the FAR(s), QER(s), etc. corresponding to the multicast / broadcast QoS flow to the PSA-UPF / UPF when / before / after establishing, adding, modifying or updating the PFCP session context.

[0425] Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" includes a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, when / before / after establishing, adding, modifying or updating the PFCP session context, the SMF shall not establish, add, modify or update the PDR(s), FAR(s), QER(s), URR(s), etc. corresponding to the multicast / broadcast QoS flow, or shall not provide the PDR(s), FAR(s), QER(s), URR(s), etc. corresponding to the multicast / broadcast QoS flow to the PSA-UPF / UPF.

[0426] Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" includes a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the SMF shall not establish, add, modify or update the PDR(s) corresponding to the multicast / broadcast QoS flow or shall not provide the PDR(s) corresponding to the multicast / broadcast QoS flow to the PSA-UPF / UPF when / before / after establishing, adding, modifying or updating the PFCP session context.

[0427] Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" includes a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the SMF shall not establish, add, modify or update the PDR(s), PDR(s), FAR(s) corresponding to the multicast / broadcast QoS flow, or provide the PDR(s), FAR(s) corresponding to the multicast / broadcast QoS flow to the PSA-UPF / UPF when / before / after establishing, adding, modifying or updating the PFCP session context.

[0428] Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" includes a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the SMF shall not establish, add, modify or update the PDR(s), FAR(s), QER(s) corresponding to the multicast / broadcast QoS flow, or provide the PDR(s), FAR(s), QER(s) corresponding to the multicast / broadcast QoS flow to the PSA-UPF / UPF when / before / after adding or modifying the PFCP session context.

[0429] Optionally, if the "QoS Flow Accept List" of the "Path Switch Request Forwarding" includes a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the SMF shall not establish, add, modify or update the FAR(s), QER(s), URR(s) corresponding to the multicast / broadcast QoS flow or provide the FAR(s), QER(s), URR(s) corresponding to the multicast / broadcast QoS flow to the PSA-UPF / UPF when / before / after adding or modifying the PFCP session context.

[0430] (2) If a PDU session associated with a multicast / broadcast service contains only unicast QoS flows to which multicast / broadcast QoS flows are mapped, it is also applicable that the SMF initiates the release of the first transmission resource of the terminal.

[0431] Herein, a PDU session associated with a multicast / broadcast service may also be referred to as a unicast fall-back PDU session, a PDU session for the 5GC shared delivery method to individual delivery method switch, a PDU session corresponding to the 5GC individual delivery method, or a PDU session corresponding to the individual delivery method.

[0432] It should be understood that the other steps in Figure 15 are not described in detail, and these steps should be understood as the prior art in Xn handover, and the details will not be described again.

[0433] According to the communication method for multicast / broadcast services provided in this application, when the SME determines that the reference location of the terminal is outside the service area of ​​the first multicast / broadcast service, the SME notifies the UPF to initiate the release of the first transmission resource of the terminal, thereby effectively saving network resources and avoiding resource waste caused by invalid forwarding.

[0434] Second, method 1200 is described using an example in which the network device is an S-gNB.

[0435] First, the application of method 1200 to an N2 handover scenario will be described, as shown in Figures 16A and 16B, in which method 1200 is applicable to a scenario in which the S-gNB supports multicast / broadcast functionality and the T-gNB does not support multicast / broadcast functionality, a scenario in which both the S-gNB and the T-gNB support multicast / broadcast functionality, or a scenario in which the S-gNB does not support multicast / broadcast functionality and the T-gNB supports multicast / broadcast functionality.

[0436] Specifically, the handover may include the following steps:

[0437] S1601. The UE sends a measurement report to the S-gNB. In response, the S-gNB receives the measurement report, determines a target cell, and decides to handover the UE to the T-gNB where the target cell is located.

[0438] S1602. The S-gNB determines that the reference location information of the UE is not within the service area of ​​the first multicast / broadcast service. The reference location information may be the location information of the UE at the T-gNB of the UE, and the location information may be an identifier of a target cell, an identifier of the T-gNB, an identifier of a target tracking area, etc.

[0439] Specifically, after the S-gNB selects the target cell, it stores the service area in the corresponding context information obtained when the terminal joins the first multicast / broadcast service on the S-gNB. Thus, the S-gNB may determine that the terminal's location information in the target cell is not within the service area of ​​the first multicast / broadcast service.

[0440] The S-gNB then notifies the SMF to release or delete the first transmission resource via S1603 to S1606.

[0441] Specifically, the S-gNB performs operations based on the Handover Required information element in the hierarchical structure formed by the Handover Required information element defined in 3GPP TS 38.413. For example, but not limited to, one or more of the following methods may be used:

[0442] (1) If a PDU session associated with a multicast / broadcast service includes only unicast QoS flows to which multicast / broadcast QoS flows are mapped, the S-gNB may perform the following operations:

[0443] Optionally, the S-gNB does not include a "DL forwarding" information element in the QoS flow information item corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped.

[0444] Optionally, the S-gNB includes a "DL forwarding" information element in the QoS flow information item corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, but does not set the unicast QoS flow to which the multicast / broadcast QoS flow is mapped to proposed (or recommended) downlink forwarding (according to 3GPP TS 38413, this is explained in English as "it is set to "DL forwarding proposed"").

[0445] Optionally, the S-gNB includes a "DL forwarding" information element in the QoS flow information item corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, but does not perform parameter padding for the DL forwarding.

[0446] It should be noted that a unicast QoS flow to which a multicast / broadcast QoS flow is mapped may be understood as a unicast QoS flow corresponding to the multicast / broadcast QoS flow.

[0447] It should be understood that parameter padding may be, for example, actual parameters corresponding to format parameters, actual parameters corresponding to variables, actual values ​​corresponding to information elements, or values ​​corresponding to fields.

[0448] (2) If a PDU session associated with a multicast / broadcast service includes another unicast QoS flow in addition to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, the S-gNB may further perform the following operations in addition to the above-mentioned method. Note that the following operations are not exhaustive and are not limited to the above.

[0449] Alternatively, the S-gNB may not include any QoS flow information items in the QoS flow information list or may set the QoS flow information list to null.

[0450] Herein, a PDU session associated with a multicast / broadcast service may also be referred to as a unicast fall-back PDU session, a PDU session for the 5GC shared delivery method to individual delivery method switch, a PDU session corresponding to the 5GC individual delivery method, or a PDU session corresponding to the individual delivery method.

[0451] It should be understood that other steps in Figures 16A and 16B are not described in detail, and these steps should be understood as prior art in N2 handover, and the details will not be described again.

[0452] According to the communication method for multicast / broadcast services provided in this application, when the S-gNB determines that the reference location of the terminal is outside the service area of ​​the first multicast / broadcast service, the S-gNB notifies the SMF to initiate the release of the first transmission resource of the terminal, thereby effectively saving network resources and avoiding resource waste caused by invalid forwarding.

[0453] Next, the application of a network device that is an S-gNB to an Xn handover scenario will be described, as shown in Figure 17. In this scenario, the network device that is an S-gNB is applicable to a scenario where the S-gNB supports multicast / broadcast functionality and the T-gNB does not support multicast / broadcast functionality.

[0454] S1701. The UE sends a measurement report to the S-gNB, and in response, the S-gNB receives the measurement report, determines a target cell, and decides to hand over the UE to the T-gNB where the target cell is located.

[0455] S1702. The S-gNB determines that the reference location information of the UE is not within the service area of ​​the first multicast / broadcast service. The reference location information may be the location information of the UE at the T-gNB of the UE, and the location information may be an identifier of a target cell, an identifier of the T-gNB, an identifier of a target tracking area, etc.

[0456] Specifically, after the S-gNB selects the target cell, it stores the service area in the corresponding context information obtained when the terminal joins the first multicast / broadcast service on the S-gNB. Thus, the S-gNB may determine that the terminal's location information in the target cell is not within the service area of ​​the first multicast / broadcast service.

[0457] The S-gNB then notifies the SMF to release or delete the first transmission resource via S1703 to S1708.

[0458] Specifically, the S-gNB performs operations based on the handover request information element in the hierarchical structure formed by the handover request information element defined in 3GPP TS38.423. For example, but not limited to, one or more of the following methods may be used:

[0459] (1) If a PDU session associated with a multicast / broadcast service includes only unicast QoS flows to which multicast / broadcast QoS flows are mapped, the S-gNB may perform the following operations:

[0460] Optionally, the S-gNB does not include a "QoS flow identifier" information element in the QoS flow item to be set up corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped.

[0461] Optionally, the S-gNB does not include a "QoS flow-level QoS parameters" information element in the QoS flow item to be set up corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped.

[0462] Optionally, the S-gNB does not include in the "QoS flow list to be set up" a "QoS flow item to be set up" information element corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped.

[0463] Optionally, the S-gNB includes a "QoS flow identifier" information element in the QoS flow item to be set up corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, but does not perform parameter padding on the QoS flow identifier.

[0464] Optionally, the S-gNB includes a "QoS flow-level QoS parameters" information element in the QoS flow item to be set up corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, but does not perform parameter padding for the "QoS flow-level QoS parameters".

[0465] Optionally, the S-gNB includes in the "QoS flow list to be set up" a "QoS flow item to be set up" information element corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, but does not perform parameter padding for the "QoS flow item to be set up".

[0466] It should be understood that parameter padding may be, for example, actual parameters corresponding to format parameters, actual parameters corresponding to variables, actual values ​​corresponding to information elements, or values ​​corresponding to fields.

[0467] (2) If a PDU session associated with a multicast / broadcast service further includes another unicast QoS flow in addition to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, the S-gNB may further perform the following operations in addition to the above-mentioned method.

[0468] Optionally, the S-gNB does not include any "QoS flow items to be set up" in the "QoS flow list to be set up".

[0469] Optionally, the S-gNB includes in the "QoS flow list to be set up" a "QoS flow item to be set up" corresponding to the unicast QoS flow to which the multicast / broadcast QoS flow is mapped, but does not perform parameter padding for the "QoS flow item to be set up."

[0470] Optionally, the S-gNB does not include the "QoS flow list to be set up" information element in the "PDU session resource item to be set up".

[0471] Optionally, the S-gNB includes the "QoS flow list to be set up" information element in the "PDU session resource item to be set up", but does not perform parameter padding for the "QoS flow list to be set up".

[0472] Optionally, the S-gNB does not include the information element "PDU session resource item to be set up" in the "PDU session resource list to be set up".

[0473] Optionally, the S-gNB includes the information element "PDU session resource item to be set up" in the "PDU session resource list to be set up", but does not perform parameter padding for the "PDU session resource item to be set up".

[0474] It should be noted that a PDU session associated with a multicast / broadcast service may also be called a unicast fall-back PDU session, a 5GC shared delivery method to individual delivery method switch PDU session, a PDU session corresponding to the 5GC individual MBS traffic delivery method, a PDU session corresponding to the 5GC individual delivery method, or a PDU session corresponding to the individual delivery method.

[0475] It should be understood that the other steps in Figure 17 are not described in detail, and these steps should be understood as the prior art in Xn handover, and the details will not be described again.

[0476] According to the communication method for multicast / broadcast services provided in this application, when the S-gNB determines that the reference location of the terminal is outside the service area of ​​the first multicast / broadcast service, the S-gNB notifies the SMF to initiate the release of the first transmission resource of the terminal, thereby effectively saving network resources and avoiding resource waste caused by invalid forwarding.

[0477] 18 is a schematic flowchart of a communication method 1800 for multicast / broadcast services according to an embodiment of the present application. The method 1800 includes at least the following steps:

[0478] It should be noted that method 1800 is applicable to a scenario in which the S-gNB does not support the first multicast / broadcast service, but the T-gNB supports the first multicast / broadcast service.

[0479] Specifically, the following steps are included:

[0480] S1810. The T-gNB acquires reference location information of the terminal, where the reference location information represents the reference location of the terminal.

[0481] Optionally, the T-gNB receives reference location information of the terminal from the S-gNB, where the reference location information includes location information of the terminal at the T-gNB of the terminal.

[0482] Optionally, the T-gNB may accept handover request information from the S-gNB, where the handover request information includes location information of the terminal at the T-gNB.

[0483] S1820. The T-gNB does not accept the transfer of data of the first multicast / broadcast service to the terminal from the S-gNB of the terminal.

[0484] Alternatively, the T-gNB discards the transfer of data of the first multicast / broadcast service from the S-gNB to the terminal.

[0485] Specifically, when the terminal's reference location is outside the service area of ​​the first multicast / broadcast service, the T-gNB does not accept / discard data transfer of the first multicast / broadcast service to the terminal from the terminal's source access network device.

[0486] It should be noted that a PDU session associated with a multicast / broadcast service may also be called a unicast fall-back PDU session, a 5GC shared delivery method to individual delivery method switch PDU session, a PDU session corresponding to the 5GC individual MBS traffic delivery method, a PDU session corresponding to the 5GC individual delivery method, or a PDU session corresponding to the individual delivery method.

[0487] For example, the embodiments may be applied to an Xn handover scenario, as shown in FIG.

[0488] Specifically, the following major steps are included:

[0489] S1902. The S-gNB sends a handover request to the T-gNB.

[0490] For example, the handover request may include PDU session information of the UE to be handed over. The PDU session information may include an identifier of the PDU session and QoS information corresponding to a unicast QoS flow included in the PDU session. If the PDU session information of the UE to be handed over is further associated with a multicast / broadcast service, the PDU session information may further include QoS information corresponding to the QoS flow corresponding to the associated multicast / broadcast service. For example, the QoS information of the unicast QoS flow includes a unicast QFI and QoS parameters corresponding to the unicast QoS flow, and the QoS information of the QoS flow of the multicast / broadcast service includes a unicast QFI to which the multicast / broadcast QFI corresponding to the multicast / broadcast service is mapped and QoS parameters corresponding to the QFI.

[0491] Additionally, the handover request may further include a QFI of a QoS flow that the S-gNB expects to forward to the T-gNB and a forwarding tunnel endpoint identifier generated by the S-gNB. For example, the QoS flow that the S-gNB expects to forward to the T-gNB may be a unicast QoS flow (including a unicast QoS flow to which a multicast / broadcast QoS flow is mapped).

[0492] Additionally, according to the definition of the handover request information element in 3 GPP TS 38.423, the handover request may further include location information or location area (e.g., Global NG-RAN Node ID) corresponding to the UE on the source base station.

[0493] S1903. When the T-gNB determines that the terminal's reference location information is outside the service area of ​​the first multicast / broadcast service, the T-gNB does not accept the transfer of data of the first multicast / broadcast service from the S-gNB to the terminal.

[0494] Specifically, if the T-gNB stores a service area in the context information corresponding to a first multicast / broadcast service to which another terminal subscribes on the T-gNB, the T-gNB determines that the location information corresponding to the terminal on the S-gNB is not within the service area.

[0495] The T-gNB may perform the following operations according to the definition of the handover request information element in 3GPP TS 38.423. It should be noted that the following operations are not exhaustive or limiting.

[0496] (1) If a PDU session associated with a multicast / broadcast service includes a unicast QoS flow to which a multicast / broadcast QoS flow is mapped, the T-gNB may perform the following operations:

[0497] Optionally, the T-gNB may not recommend (or may not include) an entry corresponding to the QoS flow in the "QoS Flow Allowed List".

[0498] Optionally, the T-gNB may recommend (or may include) an entry corresponding to the QoS flow in the "QoS Flow Allowed List", but does not perform parameter padding on the entry corresponding to the QoS flow.

[0499] Optionally, the T-gNB may not recommend (or may not include) the inclusion of an item corresponding to the QoS flow in the "QoS Flow Allowed List", and the T-gNB may recommend (or may include) the inclusion of an item corresponding to the QoS flow in the "QoS Flow Not Allowed List".

[0500] Optionally, the T-gNB may not recommend (or may not include) an item corresponding to the QoS flow in the "QoS Flow Allow List", and the T-gNB may not recommend (or may not include) an item corresponding to the QoS flow in the "QoS Flow Accept List for Data Forwarding".

[0501] Optionally, the T-gNB may not recommend (or may not include) an item corresponding to the QoS flow in the "QoS Flow Allow List", and the T-gNB may recommend (or may include) an item corresponding to the QoS flow in the "QoS Flow Accept List for Data Forwarding", but may not perform parameter padding on the item corresponding to the QoS flow.

[0502] Optionally, the T-gNB may not recommend (or may not include) the inclusion of an item corresponding to a QoS flow in the "QoS Flow Allow List", the T-gNB may not recommend (or may not include) the inclusion of an item corresponding to a QoS flow in the "QoS Flow Admission List for Data Forwarding", and the T-gNB may not recommend (or may not include) the inclusion of an item corresponding to a QoS flow in the "QoS Flow Admission List for Data Forwarding".

[0503] Optionally, the T-gNB may not recommend (or may not include) the inclusion of an item corresponding to a QoS flow in the "QoS Flow Allow List", the T-gNB may not recommend (or may not include) the inclusion of an item corresponding to a QoS flow in the "QoS Flow Admission List for Data Forwarding", and the T-gNB may recommend (or may include) the inclusion of an item corresponding to a QoS flow in the "QoS Flow Admission List for Data Forwarding", but may not perform parameter padding on the item corresponding to the QoS flow.

[0504] It should be understood that parameter padding may be, for example, actual parameters corresponding to format parameters, actual parameters corresponding to variables, actual values ​​corresponding to information elements, or values ​​corresponding to fields.

[0505] (2) If the PDU session associated with the multicast / broadcast service further includes only a unicast QoS flow to which the multicast / broadcast QoS flow is mapped, the T-gNB may further perform the following operations in addition to the operations of the above method (1). Note that the following operations are not exhaustive and should not be considered limiting.

[0506] Optionally, the T-gNB does not include (or recommends) any items corresponding to QoS flows in the handover request acknowledgement information element.

[0507] According to the communication method for multicast / broadcast services provided in this embodiment of the present application, in the case of Xn handover, based on the location information corresponding to the terminal on the S-gNB and the service area in the context information corresponding to the multicast / broadcast service stored on the T-gNB, if the location information corresponding to the terminal on the S-gNB is not within the service area, the T-gNB skips forwarding the QoS flow corresponding to the multicast / broadcast service or does not recommend forwarding the QoS flow corresponding to the multicast / broadcast service. This solution, through the processing and operations performed by the T-gNB, can effectively save network resources and avoid resource waste caused by invalid forwarding of data for the multicast / broadcast service.

[0508] 20 is a schematic flowchart of a communication method 2000 for multicast / broadcast services according to an embodiment of the present application. The method 2000 includes at least the following steps:

[0509] S2001. The T-gNB receives a notification from the SMF indicating that a first transmission resource of the terminal is disabled and that the first transmission resource is to be used to transmit data of a first multicast / broadcast service.

[0510] S2002. The T-gNB does not establish a radio resource corresponding to the first transmission resource. The T-gNB not establishing a radio resource corresponding to the first transmission resource may be replaced by the T-gNB not preparing a radio resource corresponding to the first transmission resource or the T-gNB not allocating a radio resource corresponding to the first transmission resource.

[0511] Optionally, the T-gNB may further perform the operation of step 2102 shown in Figure 21. For example, the T-gNB sends indication information to the S-gNB of the terminal. The indication information indicates that the T-gNB will not accept transfer of data of the first multicast / broadcast service from the source access network device to the terminal.

[0512] According to the communication method for multicast / broadcast services provided in this embodiment of the present application, based on the location information corresponding to a terminal on the S-gNB and the service area in the context information corresponding to the multicast / broadcast service stored on the T-gNB, if the location information corresponding to the terminal on the S-gNB is not within the service area, the T-gNB skips forwarding the QoS flow corresponding to the multicast / broadcast service or does not recommend forwarding the QoS flow corresponding to the multicast / broadcast service. This solution, through the processes and operations performed by the T-gNB, can effectively save network resources and avoid resource waste caused by invalid forwarding of data for the multicast / broadcast service.

[0513] In the method embodiments described above, it will be understood that the methods and operations implemented by the network device may alternatively be implemented by a component (e.g., a chip or circuit) that may be used in the network device.

[0514] The method provided in the embodiment of this application has been described in detail above with reference to Figures 5 to 23A and 23B. Hereinafter, with reference to Figures 24 to 27, a communication device for multicast / broadcast services provided in the embodiment of this application will be described in detail. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for content not described in detail, please refer to the aforementioned method embodiment. For simplicity, the details will not be described again here.

[0515] In the embodiments of this application, a network device or a target access network device 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 unit may be implemented in the form of hardware or in the form of a software functional unit. It should be noted that in the embodiments of this application, the module division is an example and is merely a logical function division. In actual implementation, other division methods may be used. Hereinafter, an example obtained by dividing functional modules based on their corresponding modules will be used for explanation.

[0516] 24 is a schematic block diagram of a communication device for multicast / broadcast services according to one embodiment of the present application. As shown in the figure, the communication device for multicast / broadcast services 1000 may include a processing module 1100 and a transceiver module 1200.

[0517] In a possible design, the communication device 1000 for multicast / broadcast services corresponds to the network device in the aforementioned method embodiments, and specifically may be a chip configured in the SMF or S-gNB in ​​the aforementioned embodiments.

[0518] Specifically, the communications apparatus 1000 for multicast / broadcast services may include modules configured to perform the methods performed by the network device in method 500 of FIG. 5, method 700 of FIG. 7, method 800 of FIG. 8A and FIG. 8B, method 900 of FIG. 9, method 1200 of FIG. 12, method 1300 of FIG. 13, method 1400 of FIG. 14A and FIG. 14B, or method 1500 of FIG. 15. Additionally, the modules within communication device 1000 for multicast / broadcast services and other operations and / or functions described above are for implementing corresponding procedures in method 500 of FIG. 5, method 700 of FIG. 7, method 800 of FIG. 8A and FIG. 8B, method 900 of FIG. 9, method 1200 of FIG. 12, method 1300 of FIG. 13, method 1400 of FIG. 14A and FIG. 14B, method 1500 of FIG. 15, method 2200 of FIG. 22A and FIG. 22B, or method 2300 of FIG. 23A and FIG. 23B, respectively.

[0519] When the communication device 1000 for multicast / broadcast services is configured to perform the method 500 of FIG. 5, the processing module 1100 may be configured to perform steps 510 and 520 of the method 500.

[0520] When the communication device 1000 for multicast / broadcast services is configured to perform the method 700 of FIG. 7, the processing module 1100 may be configured to perform step 720 of the method 700, and the transceiver module 1200 may be configured to perform steps 703 and 704 of the method 700.

[0521] When the communication device 1000 for multicast / broadcast services is configured to perform the method 800 of Figures 8A and 8B, the processing module 1100 may be configured to perform step 809 of the method 800, and the transceiver module 1200 may be configured to perform steps 805 to 808 and step 810 of the method 800.

[0522] When the communication device 1000 for multicast / broadcast services is configured to perform the method 900 of FIG. 9, the processing module 1100 may be configured to perform step 911 of the method 900, and the transceiver module 1200 may be configured to perform steps 907 to 910 and step 912 of the method 900.

[0523] When the communication device 1000 for multicast / broadcast services is configured to perform the method 1200 of FIG. 12, the processing module 1100 may be configured to perform steps 1201 and 1202 of the method 1200.

[0524] When the communication device 1000 for multicast / broadcast services is configured to perform the method 1300 of FIG. 13, the processing module 1100 may be configured to perform steps 1302 and 1305 of the method 1300, and the transceiver module 1200 may be configured to perform steps 1303 and 1304 of the method 1300.

[0525] When the communication device 1000 for multicast / broadcast services is configured to perform the method 1400 of FIGS. 14A and 14B, the processing module 1100 may be configured to perform step 1409 of the method 1400, and the transceiver module 1200 may be configured to perform steps 1405 to 1408 and step 1410 of the method 1400.

[0526] When the communication device 1000 for multicast / broadcast services is configured to perform the method 1500 of FIG. 15, the processing module 1100 may be configured to perform step 1511 of the method 1500, and the transceiver module 1200 may be configured to perform steps 1507 to 1510 and step 1512 of the method 1500.

[0527] When the communication device 1000 for multicast / broadcast services is configured to perform the method 2200 of Figures 22A and 22B, the processing module 1100 may be configured to perform step 2209 of the method 2200, and the transceiver module 1200 may be configured to perform steps 2205 to 2208 and step 2210 of the method 2200.

[0528] When the communication device 1000 for multicast / broadcast services is configured to perform the method 2300 of Figures 23A and 23B, the processing module 1100 may be configured to perform step 2309 of the method 2300, and the transceiver module 1200 may be configured to perform steps 2305 to 2308 and step 2310 of the method 2300.

[0529] 25 is a schematic block diagram of a communication device for multicast / broadcast services 2000 according to one embodiment of the present application. As shown in the figure, the communication device for multicast / broadcast services 2000 may include a transceiver module 2100 and a processing module 2200.

[0530] In a possible design, the communication device 2000 for multicast / broadcast services corresponds to the network device in the aforementioned method embodiments, and specifically may be an S-gNB or a chip configured in an S-gNB in ​​the aforementioned embodiments.

[0531] Specifically, communications apparatus 2000 for multicast / broadcast services may include modules configured to perform the methods performed by the network devices in method 500 of Figure 5, method 1000 of Figures 10A and 10B, method 1100 of Figure 11, method 1200 of Figure 12, method 1600 of Figures 16A and 16B, or method 1700 of Figure 17. Additionally, the modules in communications apparatus 2000 for multicast / broadcast services and other operations and / or functions described above are for implementing corresponding procedures in method 500 of Figure 5, method 1000 of Figures 10A and 10B, method 1100 of Figure 11, method 1200 of Figure 12, method 1600 of Figures 16A and 16B, or method 1700 of Figure 17, respectively.

[0532] When the communications device 1000 for multicast / broadcast services is configured to perform the method 500 of FIG. 5, the processing module 2200 may be configured to perform steps 510 and 520 of the method 500.

[0533] When the communication device 2000 for multicast / broadcast services is configured to perform the method 1000 of FIGS. 10A and 10B, the transceiver module 2100 may be configured to perform steps 1001 and 1003 of the method 1000, and the processing module 2200 may be configured to perform step 1002 of the method 1000.

[0534] When the communications device 2000 for multicast / broadcast services is configured to perform the method 1100 of FIG. 11 , the transceiver module 2100 may be configured to perform steps 1001 and 1003 of the method 1100, and the processing module 2200 may be configured to perform step 1102 of the method 1100.

[0535] When the communications device 2000 for multicast / broadcast services is configured to perform the method 1200 of FIG. 12, the processing module 2200 may be configured to perform steps 1201 and 1202 of the method 1200.

[0536] When the communications device 2000 for multicast / broadcast services is configured to perform the method 1600 of FIGS. 16A and 16B, the transceiver module 2100 may be configured to perform steps 1601 and 1603 of the method 1600, and the processing module 2200 may be configured to perform step 1602 of the method 1600.

[0537] When the communications device 2000 for multicast / broadcast services is configured to perform the method 1700 of FIG. 17, the transceiver module 2100 may be configured to perform steps 1701 and 1703 of the method 1700, and the processing module 2200 may be configured to perform step 1702 of the method 1700.

[0538] 26 is a schematic block diagram of a communication device 3000 for multicast / broadcast services according to one embodiment of the present application. As shown in the figure, the communication device 3000 for multicast / broadcast services may include a transceiver module 3100 and a processing module 3200.

[0539] In a possible design, the communications apparatus 3000 for multicast / broadcast services may correspond to a target access network device in the aforementioned method embodiments, or a chip configured within a target access network device.

[0540] Specifically, communications apparatus 3000 for multicast / broadcast services may include modules configured to perform the method performed by the target access network device in method 1800 of Figure 18, method 1900 of Figure 19, method 2000 of Figure 20, or method 2100 of Figure 21. Additionally, the modules in communications apparatus 3000 for multicast / broadcast services and other operations and / or functions described above are for implementing corresponding procedures in method 1800 of Figure 18, method 1900 of Figure 19, method 2000 of Figure 20, or method 2100 of Figure 21, respectively.

[0541] When the communications device 3000 for multicast / broadcast services is configured to perform the method 1800 of FIG. 18, the processing module 3200 may be configured to perform steps 1810 and 1820 of the method 1800.

[0542] When the communications device 3000 for multicast / broadcast services is configured to perform the method 1900 of FIG. 19, the transceiver module may be configured to perform steps 1902, 1904, and 1907 in the method 1900, and the processing module 3200 may be configured to perform step 1903 in the method 1900.

[0543] When the communication device 3000 for multicast / broadcast services is configured to perform the method 2000 of FIG. 20, the transceiver module may be configured to perform step 2001 of the method 2000, and the processing module 3200 may be configured to perform step 2002 of the method 2000.

[0544] When the communications device 3000 for multicast / broadcast services is configured to perform the method 2100 of FIG. 21, the transceiver module may be configured to perform steps 2101 and 2102 of the method 2100.

[0545] As shown in FIG. 27, an embodiment of the present application further provides a communication device 2500 for multicast / broadcast services. The communication device 2500 for multicast / broadcast services includes a processor 2510. The processor 2510 is coupled to a memory 2520. The memory 2520 is configured to store computer programs or instructions and / or data. The processor 2510 is configured to execute the computer programs or instructions and / or data stored in the memory 2520 to enable the method in the aforementioned method embodiment to be performed.

[0546] Optionally, the communications apparatus 2500 for multicast / broadcast services includes one or more processors 2510 .

[0547] Optionally, as shown in FIG. 17, the communication apparatus 2500 for multicast / broadcast services may further include a memory 2520.

[0548] Optionally, there may be one or more memories 2520 included in the communication device 2500 for multicast / broadcast services.

[0549] Optionally, memory 2520 and processor 2510 may be integrated together or located separately.

[0550] 27, the communication device 2500 for multicast / broadcast services may further include a transceiver 2530. The transceiver 2530 is configured to transmit and / or receive signals. For example, the processor 2510 is configured to control the transceiver 2530 to transmit and / or receive signals.

[0551] In the solution, a communications apparatus 2500 for multicast / broadcast services is configured to implement the operations performed by a network device or a target access network device in the aforementioned method embodiments.

[0552] An embodiment of the present application further provides a computer-readable storage medium storing computer instructions for implementing a method performed by a network device or a target access network device in the aforementioned method embodiments.

[0553] For example, when the computer program is executed by a computer, the computer can implement the method performed by the terminal device or the method performed by the network device in the above-mentioned method embodiments.

[0554] An embodiment of the present application further provides a computer program product including instructions that, when executed by a computer, enable the computer to implement the method performed by the terminal device or the method performed by the network device in the aforementioned method embodiments.

[0555] An embodiment of the present application further provides a communication system for multicast / broadcast services, the communication system including the network device or target access network device in the aforementioned embodiment.

[0556] For the sake of convenience and simplicity, it will be clearly understood by those skilled in the art that the description of related content and beneficial effects in any communication device for multicast / broadcast services provided above may refer to the corresponding method embodiments provided above, and the details will not be described again here.

[0557] In an embodiment of this application, a terminal device or a network device includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer may include hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also referred to as primary memory). The operating system in the operating system layer may be one or more computer operating systems that implement service processing through processes, such as a Linux operating system, a UNIX operating system, an Android operating system, an iOS operating system, or a Windows operating system. The application layer may include applications such as a browser, an address book, word processing software, and instant messaging software.

[0558] The specific structure of the implementation of the method provided in the embodiments of this application is not specifically limited to the embodiments of this application, as long as a program recording the code of the method provided in the embodiments of this application is operated to perform communication according to the method provided in the embodiments of this application. For example, the method provided in the embodiments of this application may be executed by a terminal device, a network device, or a functional module located in the terminal device or network device and capable of launching and executing a program.

[0559] Aspects or features of this application may be implemented as a method, apparatus, or article of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" as used herein may cover a computer program accessible from any computer-readable component, carrier, or media.

[0560] A computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device, such as a server or data center, that integrates one or more available media. The available medium (or computer-readable medium) may include various media that can store program code, such as, but not limited to, magnetic media or magnetic storage devices (e.g., floppy disks, hard disks (e.g., removable hard disks), or magnetic tapes), optical media (e.g., optical disks, compact discs (CDs), digital versatile discs (DVDs)), smart cards, flash memory devices (e.g., erasable programmable read-only memory (EPROM), cards, sticks, or key drives), and semiconductor media (e.g., solid-state disks (SSDs), USB flash drives, read-only memory (ROM), or random access memory (RAM)).

[0561] Various storage media described herein may represent one or more devices and / or other machine-readable media configured to store information. The term "machine-readable storage medium" may include, but is not limited to, wireless channels and various other media that can store, contain, and / or carry instructions and / or data.

[0562] It should be noted that the processor referred to in the embodiments of the present application may be a central processing unit (CPU), or may be another general-purpose processor, a digital signal processing (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc. The general-purpose processor may be a microprocessor, and the processor may be any conventional processor, etc.

[0563] It will be understood that the memory referred to in the embodiments of this application may be volatile memory or nonvolatile memory, or may include volatile memory and nonvolatile memory. Nonvolatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM). For example, RAM may be used as an external cache. By way of example and not limitation, RAM may include multiple forms of, for example, static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchlink dynamic random access memory (synchlink DRAM, SLDRAM), and direct rambus random access memory (direct rambus RAM, DR RAM).

[0564] It should be noted that when the processor is a general-purpose processor, a DSP, an ASIC, an FPGA, or another programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, the memory (storage module) may be integrated into the processor.

[0565] It should be further noted that memory as described herein includes, but is not limited to, these and any other suitable types of memory.

[0566] In some embodiments provided in this application, it should be understood that the disclosed devices and methods may be implemented in other manners. For example, the device embodiments described above are merely examples. For example, the division into units described above is merely a logical functional division, and other division schemes may be used in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not implemented. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be implemented using some interfaces. Indirect couplings or communication connections between devices or units may be implemented in electronic, mechanical, or other forms.

[0567] The aforementioned units described as separate parts may or may not be physically separate, and parts shown as units may or may not be physical units, located in one location or distributed across multiple network units. Some or all of the units may be selected based on actual requirements to implement the solutions provided in this application.

[0568] Additionally, the functional units in the embodiments of this application may be integrated into one processing unit, each of the units may exist physically alone, or two or more units may be integrated into one unit.

[0569] All or part of the above-described embodiments may be implemented using software, hardware, firmware, or any combination thereof.

[0570] When software is used to implement the above-described 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, the procedures or functions according to the embodiments of this application are generated, in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. For example, the computer may be a personal computer, a server, or a network device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio, or microwave). See the above description of computer-readable storage media.

[0571] The above description is merely a specific implementation of this application, but is not intended to limit the scope of protection of this application. Any modifications or substitutions that can be easily understood by those skilled in the art within the technical scope disclosed in this application shall be included in the scope of protection of this application. Therefore, the scope of protection of this application shall be subject to the scope of protection of the claims and this specification.

Claims

1. 1. A communication method for multicast / broadcast services, comprising: obtaining, by a network device, reference location information of a terminal, wherein the reference location information represents a reference location of the terminal; determining, by the network device, that the reference location of the terminal is within a service area of ​​a first multicast / broadcast service; triggering, by the network device, a target access network device of the terminal to allocate transmission resources to the terminal in response to determining that the reference location of the terminal is within a service area of ​​a first multicast / broadcast service, wherein the transmission resources are used to transmit data of the first multicast / broadcast service; the network device is a session management function network element; The method, wherein the reference location information includes location information of the terminal at the target access network device of the terminal.

2. The method of claim 1 , wherein the location information is an identifier of a target cell of the terminal and / or an identifier of the target access network device.

3. 1. A communication method for multicast / broadcast services, comprising: obtaining, by a network device, reference location information of a terminal, wherein the reference location information represents a reference location of the terminal; determining, by the network device, that the reference location of the terminal is outside a service area of ​​a first multicast / broadcast service; initiating, by the network device, release of first transmission resources of the terminal in response to determining that the reference location of the terminal is outside a service area of ​​a first multicast / broadcast service, the first transmission resources being used to transmit data of the first multicast / broadcast service; the network device is a session management function network element; The method, wherein the reference location information includes location information of the terminal at the target access network device of the terminal.

4. 4. The method of claim 3, wherein the first transmission resource comprises a resource used by the terminal to transmit the data of the first multicast / broadcast service via a target access network device of the terminal.

5. The method comprises: The method of claim 4 , further comprising: determining, by the network device, that the terminal is outside a service area of ​​the first multicast / broadcast service based on the reference location information.

6. Obtaining, by the network device, reference location information of the terminal, The method of any one of claims 3 to 5, comprising receiving, by the session management function network element, a first message, wherein the first message includes the reference location information.

7. The method of claim 6 , wherein the first message is a Protocol Data Unit (PDU) Session Context Update Request or a Provide Location Information.

8. The method comprises: and further comprising subscribing, by the session management function network element, to the reference location information of the terminal from an access and mobility management network element; Receiving a first message by the session management function network element includes:

8. The method of claim 6 or 7, comprising receiving, by the Session Management Function network element, the reference location information of the terminal from the Access and Mobility Management network element.

9. The method of claim 8, wherein the step of initiating the release of the first transmission resource by the network device comprises: notifying a User Plane Function network element (UPF) by the Session Management Function network element to release the first transmission resource; and / or The method according to any one of claims 4 to 5, comprising notifying, by the Session Management Function network element, the target access network device of the terminal to release the first transmission resource.

10. Informing a UPF, by the session management function network element, to release the first transmission resource includes:

10. The method of claim 9, comprising: sending, by the Session Management Function network element, an N4 session modification request or a Packet Forwarding Control Protocol (PFCP) session modification request to a UPF to notify the UPF to release the first transmission resource.

11. A communication device for multicast / broadcast services, a memory configured to store computer instructions; and at least one processor configured to execute the computer instructions stored in the memory, thereby enabling the communication device to perform the method of any one of claims 1 to 2 or the method of any one of claims 4 to 10.

12. A computer-readable storage medium storing a computer program, the computer program being, when executed by a communication device for multicast / broadcast services, capable of enabling the communication device to perform the method of any one of claims 1 to 2 or the method of any one of claims 4 to 10.

13. 1. A communication system for multicast / broadcast services, comprising: a network device configured to perform the method according to any one of claims 1 to 2; a target access network device configured to allocate the transmission resources to the terminal.

14. A computer program comprising instructions which, when executed by a computer, enable the computer to implement the method of any one of claims 1 to 2 or the method of any one of claims 4 to 10.

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