A communication method and apparatus

Abstract

The application relates to the communication technical field, and discloses a communication method and device. The method comprises the following steps: a first communication device acquires service area information of a first service, wherein the service area information is used for indicating a service area supporting the first service to be transmitted in a first network in a first transmission mode; if a target cell of a terminal device is not in the service area, first information is sent, wherein the first information is used for establishing a first transmission path, and the first transmission path is used for transmitting data of the first service to the terminal device in the first network in a second transmission mode; or if the target cell is in the service area, the first information is not sent. By using the method, the first communication device can determine whether the target cell is in the service area according to the service area information of the first service, and then carries out different processing according to whether the target cell is in the service area, so that the data of the first service can be transmitted to the terminal device in a reasonable mode.

Description

[0001] Cross Reference to Related Applications

[0002] The application claims priority to the Chinese Patent Application No. PCT / CN2021 / 075875, filed on February 07, 2021, and entitled "Communication Method and Device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of wireless communication, in particular to a communication method and device. BACKGROUND

[0004] With the development of mobile Internet, multicast / broadcast services are widely used, for example, in the fields of high-definition video, automatic driving, Internet of Things devices and public safety warning.

[0005] To meet the transmission requirements of multicast / broadcast services, a multicast transmission mode, i.e., an evolved multimedia broadcast multicast service (eMBMS) transmission mode, is introduced in the 4th generation (4G) network. In this case, taking a first service as an example, the first service can be a multicast / broadcast service, and in the 4G network, the data of the first service can be transmitted through the eMBMS transmission mode. A multicast transmission mode, i.e., a multicast broadcast service (MBS) transmission mode, is also introduced in the 5th generation (5G) network. In this case, still taking the first service as an example, in the 5G network, the data of the first service can be transmitted through the 5G MBS transmission mode.

[0006] However, in the scenario where the 4G network and the 5G network coexist, when a terminal device moves from the 5G network to the 4G network or moves from the 4G network to the 5G network, how to transmit the data of the first service to the terminal device still needs further research. SUMMARY

[0007] The present application provides a communication method and device for transmitting the data of a first service to a terminal device when the terminal device moves from a second network to a first network or moves from the first network to the second network.

[0008] In a first aspect, an embodiment of the present application provides a communication method, which is applied to terminal equipment moving from a second network to a first network, and is used to implement the function of a core network element, for example, the method can be applied to a session management network element or a chip in the session management network element, and an embodiment of the present application is not limited to the specific execution subject of the method. Taking the method applied to a session management network element as an example, the session management network element acquires service area information of a first service, and the service area information is used to indicate a service area supporting the first service to be transmitted in the first network in a first transmission mode; if a target cell of the terminal equipment is not in the service area, first information is sent, the first information is used to establish a first transmission path, and the first transmission path is used to send data of the first service to the terminal equipment in the first network in a second transmission mode; or, if the target cell is in the service area, the first information is not sent; wherein the target cell is located in the first network.

[0009] By using the above method, the session management network element can determine whether the target cell is in the service area according to the service area information of the first service, and then perform different processing according to whether the target cell is in the service area, thereby facilitating the first service data to be sent to the terminal equipment in a reasonable manner. For example, if the target cell is not in the service area, the first information can be sent, and then the AS can send the first service data to the terminal equipment in the first network in the second transmission mode; if the target cell is in the service area, the first information can not be sent, and then the AS can send the first service data to the terminal equipment in the first network in the first transmission mode (i.e., the eMBMS transmission mode).

[0010] In a possible design, the service area information includes at least one of the following: an identifier of a public land mobile network (PLMN) corresponding to the service area; an identifier of a tracking area (TAI) corresponding to the service area; and an identifier of a cell corresponding to the service area.

[0011] In a possible design, the acquiring of the service area information of the first service includes: receiving the service area information from a first core network element, the first core network element including any of the following: a multicast service network element, a multicast session management network element, a network exposure function network element, a policy control network element, a unified data storage network element, and a unified data management network element; or receiving the service area information from the terminal equipment.

[0012] In a possible design, the receiving of the service area information from the terminal equipment includes: receiving a first message from the terminal equipment, the first message including the service area information; and the first message is a PDU session establishment request message or a PDU session modification request message.

[0013] In a possible design of the method, the first message further includes a join request, where the join request is used to request that the terminal device is served by the second network in a third transmission mode for the first service.

[0014] In a possible design of the method, the method further includes: obtaining information of the target cell; and determining, according to the information of the target cell, whether the target cell is within the service area.

[0015] In a possible design of the method, the information of the target cell includes a TAI corresponding to the target cell and / or an identifier of the target cell.

[0016] In a possible design of the method, the obtaining of the information of the target cell includes: receiving the information of the target cell from a mobility management network element.

[0017] In a possible design of the method, the information of the target cell is carried in a session context request message from the mobility management network element, where the session context request message is used to request a context of a first PDU session of the terminal device, and the first PDU session is associated with the first service.

[0018] In a possible design of the method, the method further includes: determining that the target cell is not within the service area, if the information of the target cell is not carried in the session context request message.

[0019] In a possible design of the method, the sending of the first information includes: receiving a session context request message from a mobility management network element, where the session context request message is used to request a context of a first PDU session of the terminal device, and the first PDU session is associated with the first service; and sending, to the mobility management network element, the context of the first PDU session according to the session context request message, where the context of the first PDU session includes the first information.

[0020] In a possible design of the method, the not sending of the context information includes: receiving a session context request message from a mobility management network element, where the session context request message is used to request a context of a first PDU session of the terminal device, and the first PDU session is associated with the first service; and sending, to the mobility management network element, the context of the first PDU session according to the session context request message, where the context of the first PDU session does not include the first information.

[0021] In a possible design of the method, if the target cell of the terminal device is within the service area, the method further includes: releasing resources in the second network used for sending the first service to the terminal device.

[0022] In a second aspect, an embodiment of the present application provides a communication method, which is applied to a terminal device moving from a second network to a first network, and is used to implement a function of a core network element, for example, the method can be applied to a mobility management network element or a chip in the mobility management network element, and an embodiment of the present application is not limited to the specific execution subject of the method. Taking the method applied to the mobility management network element as an example, the mobility management network element acquires service area information of a first service, and the service area information is used to indicate a service area supporting the first service to be transmitted in the first network in a first transmission mode; if a target cell of the terminal device is not in the service area, first information is sent, and the first information is used to establish a first transmission path, and the first transmission path is used to send data of the first service to the terminal device in the first network in a second transmission mode; or, if the target cell is in the service area, the context information is not sent; and the target cell is located in the first network.

[0023] By using the method, the mobility management network element can determine whether the target cell is in the service area according to the service area information of the first service, and then perform different processing according to whether the target cell is in the service area, thereby facilitating the first service data to be sent to the terminal device in a reasonable manner. For example, if the target cell is not in the service area, the first information is sent, and then the AS can send the first service data to the terminal device in the first network in the second transmission mode; if the target cell is in the service area, the first information is not sent, and then the AS can send the first service data to the terminal device in the first network in the first transmission mode (i.e., the eMBMS transmission mode).

[0024] In a possible design, the service area information includes at least one of the following: an identifier of a PLMN corresponding to the service area; a TAI corresponding to the service area; and an identifier of a cell corresponding to the service area.

[0025] In a possible design, the acquiring of the service area information of the first service includes: receiving the service area information from a second core network element, and the second core network element includes any one of the following: a session management network element, a multicast service network element, a multicast session management network element, a network exposure function network element, a unified data storage network element, and a unified data management network element.

[0026] In a possible design, the method further includes: acquiring information of the target cell; and determining whether the target cell is in the service area according to the information of the target cell.

[0027] In a possible design, the information of the target cell includes a TAI corresponding to the target cell and / or an identifier of the target cell.

[0028] In a possible design, the information of the target cell is acquired by receiving the information of the target cell from a source access network element of the terminal device, where the source access network element is located in the second network.

[0029] In a possible design, the method further includes receiving the first information from a session management network element.

[0030] In a possible design, the method further includes sending a second message to the session management network element, where the second message is used to acquire the first information.

[0031] In a possible design, the second message includes second information, where the second information is used to indicate that data of the first service is sent to the terminal device in the second transmission mode in the first network.

[0032] In a possible design, the second message is a session context request message, where the session context request message is used to request a context of a first PDU session of the terminal device, and the first PDU session is associated with the first service.

[0033] In a possible design, the method further includes determining the first PDU session associated with the first service.

[0034] In a possible design, the first PDU session associated with the first service is determined by determining, according to an S-NSSAI and / or a DNN of the first service, a PDU session corresponding to the S-NSSAI and / or the DNN as the first PDU session associated with the first service; or receiving, by the first PDU session, an identifier of the first service from the session management network element, establishing an association relationship between the first service and the first PDU session, and determining the first PDU session associated with the first service according to the association relationship.

[0035] In a possible design, if the target cell is in the service area, the method further includes sending third information to a source access network element of the terminal device, where the third information is used to redirect the terminal device to the target cell, and the source access network element is located in the second network.

[0036] In a third aspect, an embodiment of the present application provides a communication method, which is applied to terminal device moving from a second network to a first network, and is used to implement functions of an access network element, for example, the method can be applied to an access network element or a chip in the access network element, and embodiments of the present application are not limited to a specific execution subject of the method. Taking the method applied to an access network element as an example, the access network element acquires service area information of a first service, and the service area information is used to indicate a service area supporting the first service to be transmitted in the first network in a first transmission mode; if a target cell of the terminal device is not in the service area, fourth information is sent, and the fourth information is used to indicate that radio resources are allocated for the first service in the first network, and the radio resources are used to send data of the first service to the terminal device in the first network in a second transmission mode; or, if the target cell is in the service area, the terminal device is redirected to the target cell, or fifth information is sent, and the fifth information is used to indicate that the radio resources are not allocated for the first service in the first network; wherein the target cell is located in the first network.

[0037] By using the method, the source access network element can determine whether the target cell is in the service area according to the service area information of the first service, and then perform different processing according to whether the target cell is in the service area, thereby facilitating the terminal device to receive data of the first service in a reasonable manner.

[0038] In a possible design, the service area information includes at least one of the following: an identifier of a PLMN corresponding to the service area; a TAI corresponding to the service area; and an identifier of a cell corresponding to the service area.

[0039] In a possible design, the acquiring of the service area information of the first service includes: receiving the service area information from a third core network element, and the third core network element includes any of the following: a session management network element, a mobility management network element, and a multicast session management network element; or receiving the service area information from the terminal device.

[0040] In a possible design, the receiving of the service area information from the terminal device includes: receiving an RRC message from the terminal device, and the RRC message includes the service area information.

[0041] In a fourth aspect, an embodiment of the present application provides a communication method, which is applied to terminal equipment moving from a second network to a first network, and is used to implement the function of a core network element, for example, the method can be applied to a mobility management network element or a chip in the mobility management network element, and embodiments of the present application are not limited to the specific execution subject of the method. Taking the method applied to the mobility management network element as an example, the mobility management network element acquires information of a target cell of the terminal equipment, and the target cell is located in the first network; and the information of the target cell is sent to a session management network element.

[0042] In a possible design, the information of the target cell includes a TAI corresponding to the target cell and / or an identifier of the target cell.

[0043] In a possible design, the information of the target cell is sent to the session management network element, including: determining that the terminal equipment joins a multicast session of a first service, or determining that the terminal equipment receives data of the first service in a third transmission mode; sending a session context request message to the session management network element, where the session context request message includes the information of the target cell; and the session context request message is used to request a context of a first PDU session of the terminal equipment, and the first PDU session is associated with the first service.

[0044] In a possible design, the method further includes: determining the first PDU session associated with the first service.

[0045] In a possible design, the first PDU session associated with the first service is determined, including: determining, according to an S-NSSAI and / or a DNN of the first service, that a PDU session corresponding to the S-NSSAI and / or the DNN is the first PDU session associated with the first service; or receiving an identifier of the first service from the session management network element through the first PDU session to establish an association relationship between the first service and the first PDU session; and determining, according to the association relationship, the first PDU session associated with the first service.

[0046] In a possible design, the method further includes: determining that the first service supports transmission through the first network.

[0047] In a fifth aspect, an embodiment of the present application provides a communication method applied to terminal equipment moving from a second network to a first network, the method is used to implement the function of a core network element, for example, the method can be applied to a session management network element or a chip in the session management network element, and embodiments of the present application are not limited to the specific execution subject of the method. Taking the case that the method is applied to a session management network element, the session management network element receives second information or fourth information, the second information is used to indicate that data of a first service is transmitted to the terminal equipment in a second transmission mode in the first network, and the fourth information is used to indicate that a radio resource is allocated for the first service in the first network, and the radio resource is used to transmit data of the first service to the terminal equipment in the second transmission mode in the first network; according to the second information or the fourth information, first information is transmitted, the first information is used to establish a first transmission path, and the first transmission path is used to transmit data of the first service to the terminal equipment in the second transmission mode in the first network.

[0048] In a possible design, the method further includes: sending service area information of the first service to a mobility management network element or a source access network element of the terminal equipment, the service area information is used to indicate a service area supporting transmission of the first service in the first network in the first transmission mode, and the source access network element is located in the second network.

[0049] In a possible design, the method further includes: sending an identifier of the first service to a mobility management network element through a first PDU session of the terminal equipment, and the first PDU session is associated with the first service.

[0050] In a possible design, the method further includes: instructing a user plane network element to transmit data of the first service to the terminal equipment through a transmission path corresponding to the second transmission mode.

[0051] In a sixth aspect, an embodiment of the present application provides a communication method, which is applied to terminal equipment moving from a second network to a first network, and is used to implement the function of a core network element, for example, the method can be applied to a mobility management network element or a chip in the mobility management network element, and embodiments of the present application are not limited to the specific execution subject of the method. Taking the method applied to the mobility management network element as an example, the mobility management network element receives fourth information from a source access network element of the terminal equipment, the fourth information being used to indicate that a radio resource is allocated for a first service in the first network, and the radio resource is used to send data of the first service to the terminal equipment in a second transmission mode in the first network; and the mobility management network element sends second information or the fourth information to a session management network element, the second information being obtained according to the fourth information, and the second information being used to indicate that the data of the first service is sent to the terminal equipment in the second transmission mode in the first network.

[0052] It should be noted that the method described in the fourth aspect to the sixth aspect corresponds to the method described in the first aspect to the third aspect, and the beneficial effects of the related technical features in each described method can be referred to each other, and specific details are not described herein.

[0053] In a seventh aspect, an embodiment of the present application provides a communication method, which is used to implement the function of terminal equipment, for example, the method can be applied to terminal equipment or a chip in the terminal equipment, and embodiments of the present application are not limited to the specific execution subject of the method. Taking the method applied to the terminal equipment as an example, the terminal equipment obtains sixth information, the sixth information being used to indicate that a second network supports sending data of a first service in a third transmission mode; and according to the sixth information, the terminal equipment sends a join request to a network element in the second network, the join request being used to request that the data of the first service is sent to the terminal equipment in the third transmission mode in the second network.

[0054] By using the above method, the terminal equipment can determine whether the network accessed by the terminal equipment supports sending the data of the first service in the third transmission mode according to the sixth information, if the network supports, the terminal equipment can send the join request to join the multicast session of the first service, and if the network does not support, the terminal equipment can not send the join request, so that the terminal equipment can determine whether to send the join request after accessing the second network, so as to receive the data of the first service in a reasonable way.

[0055] In a possible design, the sixth information includes the identification of one or more networks, the one or more networks including the second network, and the one or more networks supporting sending the data of the first service in the third transmission mode.

[0056] In a possible design, the identity of the one or more networks is an identity of one or more PLMNs.

[0057] In a possible design, the sixth information further includes a DNN and / or an S-NSSAI corresponding to the second network.

[0058] In a possible design, the method further includes: sending, by the terminal device, the join request to a network element in the second network through a first PDU session of the terminal device, wherein a DNN and / or an S-NSSAI corresponding to the first PDU session is the same as a DNN and / or an S-NSSAI corresponding to the second network.

[0059] In a possible design, the obtaining the sixth information of the first service of the terminal device includes: receiving the sixth information from an application server; or receiving the sixth information from a multicast service network element.

[0060] In an eighth aspect, an embodiment of the present application provides a communication method, which is used to implement a function on an application server side, for example, the method can be applied to an application server or a chip in the application server, and the present application is not limited to the specific execution subject of the method. Taking the case that the method is applied to the application server as an example, the application server receives a first notification message, the first notification message is used to notify a terminal device to access a second network, and the second network supports sending data of a first service in a third transmission mode; and according to the first notification message, the application server sends seventh information, the seventh information is used to instruct to send the data of the first service to the terminal device in the third transmission mode in the second network.

[0061] By using the method, when the second network supports sending the data of the first service in the third transmission mode after the application server learns that the terminal device accesses the second network, the application server can instruct to add the terminal device to a multicast session of the first service; and optionally, when the second network does not support sending the data of the first service in the third transmission mode, the application server can not instruct to add the terminal device to the multicast session of the first service. In this way, after the terminal device accesses the second network, the data of the first service can be sent to the terminal device in a reasonable manner.

[0062] In a possible design, the first notification message includes an identity of the second network; and the method further includes: determining, by the application server, whether to support sending the data of the first service in the third transmission mode through the second network according to the identity of the second network.

[0063] In a possible design, the application server receiving the first notification message includes: receiving, by the application server, the first notification message from a fourth core network network element.

[0064] In a possible design, the application server sends the seventh information, including: the application server sending the seventh information to the fifth core network element.

[0065] In a possible design, the method further includes: sending a first subscription request, where the first subscription request is used to request sending the first notification message after the terminal device accesses the second network.

[0066] In a possible design, the seventh information is sent, including: sending the seventh information through an application policy session corresponding to a first session, where the first session is a PDU session or a PDN connection of the terminal device associated with the first service.

[0067] In a possible design, the seventh information includes an identifier corresponding to the first service in the third transmission mode.

[0068] In a ninth aspect, an embodiment of the present application provides a communication method, which is used to implement a function on an application server side, for example, the method can be applied to an application server or a chip in the application server, and the present application is not limited to the specific execution subject of the method. Taking the case that the method is applied to the application server as an example, the application server receives a second notification message, where the second notification message is used to indicate that a terminal device accesses a first network; according to the second notification message, the application server sends eighth information, where the eighth information is used to establish a second transmission path, and the second transmission path is used to send data of the first service to the terminal device in a fifth transmission mode in the first network; or, according to the second notification message, the application server sends request information, where the request information is used to request establishing a third transmission path, and the third transmission path is used to send the data of the first service to the terminal device in a first transmission mode in the first network.

[0069] By using the method, the application server can know, according to the second notification message, that the terminal device accesses the first network, and then can send the data of the first service to the terminal device through a transmission path corresponding to the fifth transmission mode or the first transmission mode.

[0070] In a possible design, the application server receives the second notification message, including: the application server receiving the second notification message from a sixth core network element.

[0071] In a possible design, the application server sends the eighth information, including: the application server sending the eighth information to a seventh core network element.

[0072] In a possible design, the method further includes: sending the data of the first service to the terminal device through the second transmission path, where a destination address of the data of the first service is an IP address of the terminal device.

[0073] In a possible design of the method, the method further includes: sending a second subscription request, where the second subscription request is used to request sending of the second notification message after the terminal device accesses the first network.

[0074] In a possible design of the method, the second subscription request includes ninth information, where the ninth information is used to indicate that the second notification message is sent when the location where the terminal device accesses does not support sending of the data of the first service in the first transmission mode.

[0075] In a possible design of the method, the second subscription request includes service area information of the first service, where the service area information is used to indicate a service area that supports transmission of the first service in the first network in the first transmission mode, and the service area information is used to determine whether the location where the terminal device accesses supports sending of the data of the first service in the first transmission mode.

[0076] In a possible design of the method, the location where the terminal device accesses includes a cell and / or a tracking area in the first network where the terminal device accesses.

[0077] In a possible design of the method, the application server sends eighth information according to the second notification message, or the application server sends request information according to the second notification message, including: the application server determines that the location where the terminal device accesses does not support sending of the data of the first service in the first transmission mode through the first network; and the application server sends the eighth information, or the application server sends the request information.

[0078] In a possible design of the method, the second notification message includes location information of the terminal device, where the location information of the terminal device is used to indicate the location where the terminal device accesses; and the method further includes: determining, according to the location information, that the location where the terminal device accesses does not support sending of the data of the first service in the first transmission mode through the first network.

[0079] In a possible design of the method, the request information includes newly-added service area information of the first service, where the newly-added service area information of the first service is used to indicate a newly-added service area of the first service, and the newly-added service area includes the location where the terminal device accesses.

[0080] In a possible design of the method, the location information of the terminal device includes information of a cell in the first network where the terminal device accesses, and / or an identity of a tracking area in the first network where the terminal device accesses.

[0081] In a tenth aspect, an embodiment of the present application provides a communication apparatus, which can be a core network element (such as a session management network element or a mobility management network element) or a chip arranged in a core network element. The communication apparatus has the function of implementing any one of the first aspect, the second aspect, the fourth aspect to the sixth aspect, for example, the communication apparatus includes a module or unit or means corresponding to the steps involved in any one of the first aspect to the sixth aspect, and the function or unit or means can be implemented by software or by hardware, or by executing corresponding software by hardware.

[0082] In a possible design, the communication apparatus includes a processing unit and a communication unit, where the communication unit can be configured to transceive signals to implement communication between the communication apparatus and another apparatus; and the processing unit can be configured to perform some internal operations of the communication apparatus.

[0083] In another possible design, the communication apparatus includes a processor, and can further include a transceiver configured to transceive signals, and the processor is configured to execute program instructions to complete the method in any possible design or implementation manner of the first aspect, the second aspect, the fourth aspect to the sixth aspect. The communication apparatus can further include one or more memories coupled to the processor, and the memories can store necessary computer programs or instructions for implementing the functions involved in any one of the first aspect, the second aspect, the fourth aspect to the sixth aspect. The processor can execute the computer programs or instructions stored in the memories, and when the computer programs or instructions are executed, the communication apparatus implements the method in any possible design or implementation manner of the first aspect, the second aspect, the fourth aspect to the sixth aspect.

[0084] In another possible design, the communication apparatus includes a processor, and the processor can be configured to be coupled to a memory. The memory can store necessary computer programs or instructions for implementing the functions involved in any one of the first aspect, the second aspect, the fourth aspect to the sixth aspect. The processor can execute the computer programs or instructions stored in the memory, and when the computer programs or instructions are executed, the communication apparatus implements the method in any possible design or implementation manner of the first aspect, the second aspect, the fourth aspect to the sixth aspect.

[0085] In another possible design, the communication apparatus includes a processor and an interface circuit, where the processor is configured to communicate with another apparatus through the interface circuit, and to execute the method in any possible design or implementation manner of the first aspect, the second aspect, the fourth aspect to the sixth aspect.

[0086] In a eleventh aspect, an embodiment of the present application provides a communication apparatus, which can be an access network element or a chip arranged in an access network element. The communication apparatus has the functions of the third aspect, for example, the communication apparatus includes modules or units or means corresponding to the steps of the third aspect, and the functions or units or means can be implemented by software or by hardware, or by a combination of hardware and software.

[0087] In a possible design, the communication apparatus includes a processing unit and a communication unit, where the communication unit can be configured to transceive signals to implement communication between the communication apparatus and another apparatus; and the processing unit can be configured to perform some internal operations of the communication apparatus.

[0088] In another possible design, the communication apparatus includes a processor, and can further include a transceiver configured to transceive signals, and the processor is configured to execute program instructions to complete the method in any possible design or implementation manner of the third aspect. The communication apparatus can further include one or more memories coupled to the processor, and the memories can store necessary computer programs or instructions for implementing the functions of the third aspect. The processor can execute the computer programs or instructions stored in the memories, and when the computer programs or instructions are executed, the communication apparatus can implement the method in any possible design or implementation manner of the third aspect.

[0089] In another possible design, the communication apparatus includes a processor, and the processor can be configured to be coupled to a memory. The memory can store necessary computer programs or instructions for implementing the functions of the third aspect. The processor can execute the computer programs or instructions stored in the memory, and when the computer programs or instructions are executed, the communication apparatus can implement the method in any possible design or implementation manner of the third aspect.

[0090] In another possible design, the communication apparatus includes a processor and an interface circuit, where the processor is configured to communicate with another apparatus through the interface circuit, and perform the method in any possible design or implementation manner of the third aspect.

[0091] In a twelfth aspect, an embodiment of the present application provides a communication apparatus, which can be a terminal device or a chip arranged in a terminal device. The communication apparatus has the functions of the seventh aspect, for example, the communication apparatus includes modules or units or means corresponding to the steps of the seventh aspect, and the functions or units or means can be implemented by software or by hardware, or by a combination of hardware and software.

[0092] In one possible design, the communication apparatus includes a processing unit and a communication unit. The communication unit can be configured to transceive signals to enable communication between the communication apparatus and other apparatuses. The processing unit can be configured to perform some internal operations of the communication apparatus.

[0093] In another possible design, the communication apparatus includes a processor and a transceiver. The transceiver can be configured to transceive signals. The processor can be configured to execute program instructions to perform the method in any of the possible designs or implementation modes of the seventh aspect. The communication apparatus can further include one or more memories coupled to the processor. The memories can store the necessary computer programs or instructions to implement the functions related to the seventh aspect. The processor can execute the computer programs or instructions stored in the memories, which, when executed, cause the communication apparatus to perform the method in any of the possible designs or implementation modes of the seventh aspect.

[0094] In another possible design, the communication apparatus includes a processor and a memory. The memory can store the necessary computer programs or instructions to implement the functions related to the seventh aspect. The processor can execute the computer programs or instructions stored in the memories, which, when executed, cause the communication apparatus to perform the method in any of the possible designs or implementation modes of the seventh aspect.

[0095] In another possible design, the communication apparatus includes a processor and an interface circuit. The processor can be configured to communicate with other apparatuses through the interface circuit and perform the method in any of the possible designs or implementation modes of the seventh aspect.

[0096] In a thirteenth aspect, embodiments of the present application provide a communication apparatus. The communication apparatus can be an application server or a chip disposed in the application server. The communication apparatus has the functions of the eighth aspect or the ninth aspect, such as including modules or units or means corresponding to the steps related to the eighth aspect or the ninth aspect. The functions or units or means can be implemented by software or hardware, or by executing corresponding software by hardware.

[0097] In one possible design, the communication apparatus includes a processing unit and a communication unit. The communication unit can be configured to transceive signals to enable communication between the communication apparatus and other apparatuses. The processing unit can be configured to perform some internal operations of the communication apparatus.

[0098] In another possible design, the communication device includes a processor and may further include a transceiver for transmitting and receiving signals. The processor executes program instructions to perform the methods in any possible design or implementation of the eighth or ninth aspect described above. The communication device may also include one or more memories coupled to the processor, which may store necessary computer programs or instructions for implementing the functions involved in the eighth or ninth aspect. The processor can execute the computer programs or instructions stored in the memory, causing the communication device to implement the methods in any possible design or implementation of the eighth or ninth aspect described above when the computer programs or instructions are executed.

[0099] In another possible design, the communication device includes a processor that can be coupled to a memory. The memory can store necessary computer programs or instructions for implementing the functions described in the eighth or ninth aspect above. The processor can execute the computer programs or instructions stored in the memory, causing the communication device to implement the methods in any possible design or implementation of the eighth or ninth aspect above, when executed.

[0100] In another possible design, the communication device includes a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and to perform the methods in any possible design or implementation of the eighth or ninth aspect described above.

[0101] Understandably, in aspects ten, eleven, twelve, and thirteen above, the processor can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit, integrated circuit, etc.; when implemented in software, the processor can be a general-purpose processor that reads software code stored in memory. Furthermore, there can be one or more processors, and one or more memories. The memory can be integrated with the processor or separated from it. In specific implementations, the memory can be integrated with the processor on the same chip or disposed on different chips. This application does not limit the type of memory or the arrangement of the memory and processor.

[0102] In a fourteenth aspect, embodiments of this application provide a communication system, which includes the session management network element of the first aspect and the mobility management network element of the fourth aspect; or, the communication system includes the mobility management network element of the second aspect and the session management network element of the fifth aspect; or, the communication system includes the access network element of the third aspect, the session management network element of the fifth aspect and the mobility management network element of the sixth aspect.

[0103] In a fifteenth aspect, the present application provides a computer readable storage medium, wherein the computer readable storage medium stores computer readable instructions, and the computer readable instructions, when read and executed by a computer, cause the computer to perform the method in any possible design of the first aspect to the ninth aspect.

[0104] In a sixteenth aspect, the present application provides a computer program product, wherein the computer program product, when read and executed by a computer, causes the computer to perform the method in any possible design of the first aspect to the ninth aspect.

[0105] In a seventeenth aspect, the present application provides a chip, wherein the chip comprises a processor coupled with a memory, and the processor is configured to read and execute a software program stored in the memory, so as to implement the method in any possible design of the first aspect to the ninth aspect.

[0106] These aspects or other aspects of the present application will become more apparent in the following description of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0107] Figure 1 A network architecture diagram of a first network independently deployed is provided for the embodiments of the present application;

[0108] Figure 2 A network architecture diagram of a second network independently deployed is provided for the embodiments of the present application;

[0109] Figure 3 A network architecture diagram of a first network and a second network jointly deployed is provided for the embodiments of the present application;

[0110] Figure 4 A flow diagram of a process of transmitting first service data in a 4G network and a 5G network is provided for the embodiments of the present application;

[0111] Figure 5 A flow diagram corresponding to the communication method provided in the first embodiment of the present application is provided;

[0112] Figure 6 A flow diagram corresponding to the communication method provided in the second embodiment of the present application is provided;

[0113] Figure 7 A flow diagram corresponding to the communication method provided in the third embodiment of the present application is provided;

[0114] Figure 8 A flow diagram corresponding to the communication method provided in the fourth embodiment of the present application is provided;

[0115] Figure 9 A flow diagram corresponding to the communication method provided in the fifth embodiment of the present application is provided;

[0116] Figure 10 A flowchart corresponding to the communication method provided in Embodiment Six of the present application is shown in FIG. 6;

[0117] Figure 11 A possible exemplary block diagram of the apparatus involved in the embodiments of the present application is shown in FIG. 7;

[0118] Figure 12 A structural diagram of a core network element provided in the embodiments of the present application is shown in FIG. 8;

[0119] Figure 13 A structural diagram of an access network element provided in the embodiments of the present application is shown in FIG. 9;

[0120] Figure 14 A structural diagram of a terminal device provided in the embodiments of the present application is shown in FIG. 10;

[0121] Figure 15 A structural diagram of an application server provided in the embodiments of the present application is shown in FIG. 11. DETAILED DESCRIPTION

[0122] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

[0123] First, some terms in the embodiments of the present application will be explained to facilitate understanding by those skilled in the art.

[0124] (1) First network, second network

[0125] The first network and the second network can be networks supporting different communication modes, and the first network can also be referred to as a first communication mode network, and the second network can also be referred to as a second communication mode network. For example, the first network can be a 4G network, and the second network can be a 5G network, where the 5G network can also be referred to as a 5G communication system, and the 4G network can also be referred to as an evolved packet system (EPS) network or a 4G communication system. For another example, the first network can be a certain public land mobile network (PLMN) in a 4G network, and the second network can be a certain PLMN in a 5G network. It should be understood that the first network and the second network can also be other types of networks, which are not limited in particular. In the embodiments of the present application, the first network is taken as a 4G network, and the second network is taken as a 5G network as an example for description.

[0126] (2) PDN connection, PDU session

[0127] A protocol data network (PDN) connection refers to a data transmission channel established for a terminal device in a first network (such as a 4G network). One PDN connection can include one or more bearers (i.e., EPS bearers). The context of a PDN connection can include an internet protocol (IP) address used by the PDN connection, and the context of each EPS bearer in the PDN connection. The context of an EPS bearer can include quality of service (QoS) information of the EPS bearer, an EPS bearer identity (EBI), a traffic flow template (TFT), and the like.

[0128] A protocol data unit (PDU) session refers to a data transmission channel established for a terminal device in a second network (such as a 5G network). One PDU session can include one or more QoS flows. The context of a PDU session can include an IP address used by the PDU session, and information of each QoS flow in the PDU session. The information of a QoS flow can include QoS information of the QoS flow, a QoS flow identity (QFI), and a QoS flow template.

[0129] Exemplarily, a PDN connection in a 4G network and a PDU session in a 5G network can have a corresponding relationship. In a scenario where a 4G network and a 5G network coexist, when a terminal device moves from a 5G network to a 4G network, a PDN connection 1 corresponding to a PDU session 1 of the terminal device is established in the 4G network. For example, the context of the PDN connection 1 can be obtained according to the context of the PDU session 1, and then the PDN connection 1 can be established according to the context of the PDN connection 1. The implementation of obtaining the context of the PDN connection 1 according to the context of the PDU session 1 can refer to the prior art. For example, the IP addresses of the PDU session 1 and the PDN connection 1 can be the same. The PDU session 1 includes a first QoS flow, the first QoS flow can be one service data flow or a group of service data flows, the PDN connection 1 can include a first EPS bearer, and then the first QoS flow can be mapped to the first EPS bearer according to a predefined mapping rule, and the context of the first EPS bearer can be obtained according to the information of the first QoS flow.

[0130] (3) Transmission mode

[0131] Five transmission modes are involved in the embodiments of the present application, which are a first transmission mode, a second transmission mode, a third transmission mode, a fourth transmission mode, and a fifth transmission mode.

[0132] The first transmission manner can be a multicast transmission manner of the first network (such as a 4G network), and the multicast transmission manner can be understood as point to multi-point (PTM) communication. The first transmission manner can be applicable to a scenario in which the first network and the second network are jointly deployed (or the first network and the second network coexist), or can be applicable to a scenario in which the first network is independently deployed. The first transmission manner can refer to transmitting data to the terminal device through a multicast bearer, where the multicast bearer can also be referred to as an MBMS bearer. The first transmission manner can also be referred to as a multicast bearer transmission manner, or an MBMS bearer transmission manner, or an eMBMS transmission manner. In the first transmission manner, the destination address of the data packet is a multicast IP address.

[0133] The fifth transmission manner can be a unicast transmission manner of the first network (such as a 4G network), and the unicast transmission manner can be understood as point to point (PTP) communication. The fifth transmission manner can be applicable to a scenario in which the first network and the second network are jointly deployed, or can be applicable to a scenario in which the first network is independently deployed. The fifth transmission manner can refer to transmitting data to the terminal device through a PDN connection (or an EPS bearer, which can also be referred to as an EPS unicast bearer or a unicast bearer). In the fifth transmission manner, the destination address of the data packet is an IP address of the terminal device.

[0134] The second transmission manner can be another unicast transmission manner of the first network (such as a 4G network). The second transmission manner can be applicable to a scenario in which the first network and the second network are jointly deployed. In the second transmission manner, data is also transmitted to the terminal device through a PDN connection of the first network. The difference between the second transmission manner and the fifth transmission manner is that, in the second transmission manner, data is first transmitted to a multicast user plane network element, transmitted to a user plane network element of a PDN connection of the terminal device by the multicast user plane network element, and then transmitted to the terminal device by the user plane network element through the PDN connection; while in the fifth transmission manner, data does not pass through the multicast user plane network element. In the second transmission manner, the destination address of the data packet is a multicast IP address.

[0135] The third transmission mode can be a multicast transmission mode of the second network (such as a 5G network). The third transmission mode can be applicable to a scenario in which the first network and the second network are jointly deployed, or can also be applicable to a scenario in which the second network is independently deployed. When data of a multicast service is transmitted by using the third transmission mode, a corresponding multicast session can be created for the multicast service. One multicast service can correspond to one multicast session, one multicast service can include one or more service data flows, and the multiple service data flows can correspond to one or more multicast QoS flows, that is, data of the multicast service in the multicast session can be transmitted in the form of a multicast QoS flow, which is not limited in the embodiments of the present application. The third transmission mode can also be referred to as a 5MBS or 5G MBS transmission mode. The third transmission mode can include a shared MBS transmission mode (shared MBS delivery) and an individual MBS transmission mode (individual MBS delivery), where the shared MBS transmission mode refers to sending data to a multicast user plane network element first, sending the data to an access network element by the multicast user plane network element through a shared tunnel, and then sending the data to a terminal device by the access network element; the individual MBS transmission mode refers to sending data to a multicast user plane network element first, sending the data to an anchor user plane network element of a PDU session of the terminal device by the multicast user plane network element, and then sending the data to the terminal device by the anchor user plane network element through the PDU session. In the third transmission mode, the destination address of the data packet is a multicast IP address.

[0136] The fourth transmission mode can be a unicast transmission mode of the second network (such as a 5G network). The fourth transmission mode can be applicable to a scenario in which the first network and the second network are jointly deployed, or can also be applicable to a scenario in which the second network is independently deployed. The fourth transmission mode can refer to sending data to a terminal device through a PDU session of the terminal device; where the data in the PDU session can be transmitted in the form of a QoS flow, which is not limited in the embodiments of the present application. The difference between the fourth transmission mode and the individual MBS transmission mode in the third transmission mode is that, in the fourth transmission mode, the data packet is not transmitted through a multicast session, and the destination address of the data packet is an IP address of the terminal device.

[0137] It should be noted that "multicast" in the embodiments of the present application is a broad concept, which can include multicast (multicast) and / or broadcast (broadcast), that is, the multicast service transmission in the embodiments of the present application can be applied to multicast service transmission, or can be applied to broadcast service transmission. It can be understood that "multicast" mentioned in the embodiments of the present application can be replaced by "multicast" or "broadcast" or "multicast / broadcast".

[0138] The network architecture provided by the embodiments of the present application is described below.

[0139] I. Network architecture with first network deployed independently

[0140] Figure 1 A possible network architecture diagram of the first network independently deployed for the embodiments of the present application. For example, the first network is a 4G network, and the network architecture can support eMBMS of the 4G network. As shown in the figure, the network architecture can include the following possible devices or network elements: Figure 1

[0141] (1) Terminal device: also known as user equipment (UE), terminal, mobile station (MS), mobile terminal (MT), Customer Premise Equipment (CPE), Residential Gateway (RG), etc., which can be a device with wireless transceiver function. The terminal device can be deployed on land, including indoor, outdoor, and / or handheld or vehicle-mounted; it can also be deployed on water (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons, and satellites, etc.). The terminal device can include a handheld device, a vehicle-mounted device, a wearable device, or a computing device with wireless communication function. Exemplarily, the terminal device can be a mobile phone, a tablet computer, or a computer with wireless transceiver function. The terminal device can also be a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in telemedicine, a wireless terminal in smart power grids, a wireless terminal in smart cities, and / or a wireless terminal in smart homes, etc.

[0142] ​(2) Access network element: a node or device for connecting a terminal device to a wireless network, which can also be referred to as a radio access network (RAN) device or an access network device. The access network element includes, for example, but is not limited to, a new generation node B (gNB), an evolved node B (eNB), a next generation eNB (ng-eNB), a wireless backhaul device, a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home evolved node B (HeNB) or a home node B (HNB), a baseband unit (BBU), a transmitting and receiving point (TRP), a transmitting point (TP), a mobile switching center, an access point (AP) in a wireless local area network (WLAN), and the like. The access network element can also be a module or unit that performs part of the functions of a base station, such as a central unit (CU) or a distributed unit (DU). The embodiments of the present application do not limit the specific technology and specific device form of the access network element. For example, in a 4G network, the access network element can be an eNB.

[0143] (3) Mobility management network element: responsible for authenticating, authorizing, and mobility management of a terminal device. For example, in a 4G network, the mobility management network element can be a mobility management entity (MME).

[0144] (4) Multicast service network element: used to save subscription data, assign a temporary mobile group identity (TMGI), initiate or terminate MBMS bearer resources, and the like. For example, in a 4G network, the multicast service network element can be a broadcast-multicast service center (BM-SC).

[0145] (5) Multicast service gateway: used for receiving data of multicast service and sending the data of multicast service to access network element. For example, in a 4G network, the multicast service gateway can be an MBMS gateway (MBMS-GW), which receives data of multicast service from a BM-SC through an SGimb interface between the MBMS-GW and the BM-SC, and sends the data of multicast service to an access network element.

[0146] (6) Application server (AS): a data source of a service, used for sending data of a service to a terminal device. For example, in a 4G network, the application server can be a group communication service application server (GSC AS).

[0147] (7) Serving gateway (SGW): responsible for data forwarding, downlink data storage, etc.

[0148] (8) Packet data network gateway (PGW): the PGW includes a PGW-user plane (PGW-U) and a PGW-control plane (PGW-C), wherein the PGW-C is a control plane network element of a 4G network, and provides a control plane service for a PDN connection of a terminal device; and the PGW-U is a user plane network element of a 4G network, and provides a user plane service for the PDN connection of the terminal device.

[0149] Exemplarily, the SGW and the PGW can be combined, and when the SGW and the PGW are combined, the combined SGW and PGW can be referred to as an S / P-GW. Figure 1 The SGW and the PGW are combined as an example.

[0150] (9) Policy control network element: responsible for generating a policy for establishing a data bearer of a user. For example, in a 4G network, the policy control network element can be a policy and charging rules function (PCRF) network element.

[0151] (10) Data management network element: used for saving subscription data of a user. For example, in a 4G network, the data management network element can be a home subscriber server (HSS).

[0152] It should be noted that the above Figure 1In the network architecture shown, in addition to the terminal device and the access network element, other network elements can be referred to as core network elements. In addition, the above Figure 1 The network architecture shown can also include other possible devices or network elements, which are not limited in particular.

[0153] Based on the above Figure 1 In the network architecture shown, taking the first service as an example, the transmission path when the data of the first service is transmitted by different transmission modes is described below.

[0154] For example, the AS can send the data of the first service to the terminal device through the first transmission mode (i.e., the eMBMS transmission mode). The transmission path corresponding to the eMBMS transmission mode can be: AS→BM-SC→MBMS-GW→eNB→terminal device, i.e., the AS sends the data to the BM-SC through the MB2-U interface, the BM-SC sends the data to the MBMS-GW through the SGimb interface, the MBMS-GW sends the data to the eNB through the M1 interface, and then the eNB sends the data to the terminal device through the Uu interface (or referred to as the air interface).

[0155] For another example, the AS can also send the data of the first service to the terminal device through the fifth transmission mode. The transmission path corresponding to the fifth transmission mode can be: AS→S / P-GW→eNB→terminal device, i.e., the AS sends the data to the S / P-GW through the SGi interface, the S / P-GW sends the data to the eNB through the S1-U interface, and then the eNB sends the data to the terminal device through the Uu interface. In addition, when the SGW and the PGW are separately arranged, the transmission path corresponding to the above-mentioned fifth transmission mode can be: AS→PGW-U network element→SGW network element→eNB→terminal device.

[0156] II. Network architecture with second network deployed independently

[0157] Figure 2 A possible network architecture diagram of the second network independently deployed for the embodiments of the present application is provided. For example, the second network is a 5G network, and the network architecture can support MBS of the 5G network. As shown in the figure, Figure 2 In the network architecture shown, the following possible devices or network elements can be included:

[0158] (1) Terminal device: refer to the description above.

[0159] (2) Access network element: refer to the description above. For example, in the 5G network, the access network element can be a gNB.

[0160] (3) Mobility management network element: used for authenticating and authorizing a user, and managing mobility of the user. For example, in a 5G network, the mobility management network element can be an access and mobility management function (AMF) network element.

[0161] (4) Session management network element: used for session management, IP address allocation and management of a terminal device, and selection and management of a user plane function. For example, in a 5G network, the session management network element can be a session management function (SMF) network element.

[0162] (5) User plane network element: used for receiving user plane data and sending the user plane data to an access network network element. For example, in a 5G network, the user plane network element can be a user plane function (UPF) network element.

[0163] (6) Policy control network element: used for providing a unified policy framework for guiding network behavior, and providing policy rule information for a control plane function network element, etc. For example, in a 5G network, the policy control network element can be a policy control function (PCF) network element.

[0164] (7) Multicast session management network element: a session management network element used for controlling multicast services. For example, in a 5G network, the multicast session management network element can be a multicast / broadcast (MB)-SMF network element, which controls establishment of a path between an MB-UPF and an access network network element.

[0165] (8) Multicast user plane network element: used for transmitting data of multicast services, etc. For example, in a 5G network, the multicast user plane network element can be an MB-UPF network element.

[0166] (9) Application server: a source of data of a service, used for sending data of a service to a terminal device. For example, in a 5G network, the application server can also be replaced by an application function (AF) network element.

[0167] (10) Network exposure function (NEF) network element: provides exposure of capabilities and events of a 5G network to the outside, and receives related external messages.

[0168] (11) Multicast service network element: In a 5G network, the multicast service network element can be a multicast / broadcast service function (MBSF) network element, which can include an MBSF control plane (i.e., MBSF-C) network element and an MBSF user plane (i.e., MBSF-U) network element.

[0169] The MBSF-C network element has a service layer function, such as supporting a streaming protocol, supporting a reliable retransmission protocol, etc. The MBSF-C network element can also send a service announcement to a terminal device, distribute a multicast service key to a terminal device, etc. The MBSF-C network element can be an optional network element. When the MBSF-C network element exists, the AS can directly interface with the MBSF-C network element to send a service requirement to the core network, and then the MBSF-C network element interfaces with the MB-SMF network element to create a multicast session (optionally, the MBSF-C network element can also interface with the MB-SMF through the NEF network element). Alternatively, the AS can first interface with the NEF network element, and then the NEF network element interfaces with the MBSF-C network element, and then the MBSF-C network element interfaces with the MB-SMF network element. Exemplarily, the MBSF-C network element can be co-located with the NEF network element.

[0170] The main function of the MBSF-U network element is to process the data packets of the multicast service, such as encapsulating the data packets according to a streaming protocol, encrypting the data packets, encoding the data packets, etc. Exemplarily, the MBSF-U network element can be an optional network element. If the data packets of the multicast service need to be processed by the core network, the AS can first send the data packets to the MBSF-U network element, which processes the data packets and then sends them to the MB-UPF network element. It should be understood that in the following embodiments of the present application, the AS is described as sending the data packets to the MB-UPF network element. In actual implementation, the AS can also first send the data packets to the MBSF-U network element, which processes the data packets and then sends them to the MB-UPF network element.

[0171] It should be noted that the above Figure 2 In the network architecture shown in FIG. 1, all network elements except the terminal device and the access network network element can be referred to as core network network elements. In addition, the above Figure 2 The network architecture shown in FIG. 1 can also include other possible devices or network elements, such as a unified data repository (UDR) and a data management network element. In a 5G network, the data management network element can be a unified data management (UDM) network element.

[0172] Based on the aboveFigure 2 The network architecture shown below, taking the first service as an example, describes the transmission path when using different transmission methods to transmit the first service.

[0173] For example, the AS can send the data for the first service to the terminal device through a third transmission mode (i.e., 5MBS transmission mode). Specifically, when sending data using the third transmission mode, the AS can send the data to the MB-UPF network element ( Figure 2 The N6 interface or MB2-U interface (i.e., the direct interface between the AS and the MB-UPF network element) is used. If the access network element supports 5G MBS, the MB-UPF network element can send data to the access network element through the shared tunnel between the MB-UPF network element and the access network element (MB-N3 interface; the shared tunnel means that the MB-UPF can send one piece of data to the access network element through this tunnel, and the access network element can send it to multiple terminal devices). The access network element can flexibly decide the playback method, i.e., PTM mode or PTP mode, according to air interface conditions and the number of terminals listening to the service. In PTM mode, the access network element sends only one piece of data, which can be received by multiple terminal devices; in PTP mode, the access network element sends one piece of data, which can only be received by one terminal device. For the same service, the access network element can use both PTM and PTP modes simultaneously. For example, PTM mode can be used for terminal device 1 and terminal device 2, and PTP mode can be used for terminal device 3. Therefore, the transmission path corresponding to the shared MBS transmission mode in the third transmission mode is: AS → MB-UPF network element → gNB → terminal device. If the access network element does not support 5G MBS, the MB-UPF network element can send data to the anchor UPF network element of the PDU session. Then, the UPF network element can send data to the terminal device through the access network element via the PDU session. Therefore, the transmission path corresponding to the independent MBS transmission mode in the third transmission mode can be: AS → MB-UPF network element → UPF network element → gNB → terminal device.

[0174] For example, the AS can also send the data of the first service to the terminal device through the fourth transmission method. The transmission path corresponding to the fourth transmission method can be: AS → UPF network element → gNB → terminal device. That is, the AS sends the data to the UPF network element, the anchor point of the PDU session (the interface between the AS and this UPF network element is not shown in the figure), and then this UPF network element can send data to the terminal device through the PDU session.

[0175] III. Network architecture with first network and second network deployed jointly

[0176] Figure 3A possible network architecture diagram of the first network and the second network jointly deployed is provided for the embodiments of the present application. For example, the first network is a 4G network, and the second network is a 5G network. The network architecture can support eMBMS of the 4G network and MBS of the 5G network. As shown in Figure 3 , the network architecture can include network elements in the 4G network, network elements in the 5G network, network elements shared by the 4G network and the 5G network (or network elements jointly deployed by the 4G network and the 5G network), AS, and terminal devices. Among them, the network elements in the 4G network can include a first access network element (i.e., an eNB in the 4G network), a first mobility management network element (i.e., an MME in the 4G network), an SGW, an MBMS-GW, etc. The network elements in the 5G network can include a second access network element (i.e., a gNB in the 5G network), a second mobility management network element (i.e., an AMF network element in the 5G network), an MB-UPF, an MB-SMF, etc. The network elements shared by the 4G network and the 5G network can include a session management network element (i.e., a PGW-C+SMF), a user plane network element (i.e., a PGW-U+UPF), an MBSF+BM-SC, a policy control network element (i.e., a PCF network element), etc.

[0177] Among them, the PGW-C+SMF can include the functions of the SMF network element and the PGW-C network element. The SMF+PGW-C can also be referred to as the PGW-C+SMF, as long as the network element containing the functions of the SMF network element and the PGW-C network element is the same as the network element. The "+" in the embodiment of the present application means that the two network elements are jointly deployed.

[0178] The UPF+PGW-U can include the functions of the UPF network element and the PGW-U network element. The UPF+PGW-U can also be referred to as the PGW-U+UPF, as long as the network element containing the functions of the UPF network element and the PGW-U network element is the same as the network element.

[0179] The MBSF+BM-SC can include the functions of the MBSF network element and the BM-SC. The MBSF+BM-SC can also be referred to as the MBSF (i.e., the functions of the BM-SC are combined into the MBSF network element), as long as the network element containing the functions of the MBSF network element and the BM-SC is the same as the network element. When the MBSF network element is divided into MBSF-C and MBSF-U two parts, the functions of the corresponding BMSC are also correspondingly split into MBSF-C and MBSF-U, that is, the control plane part of the BMSC is jointly deployed with the MBSF-C, and the user plane part of the BMSC is jointly deployed with the MBSF-U. It can be understood that Figure 3The network architecture shown in FIG. 4 is taken as an example to illustrate that the MBSF network element and the BM-SC are co-located. In actual deployment, the MBSF network element and the BM-SC network element can also be deployed separately. In this case, the BM-SC and the MBSF network element can have an interface to facilitate communication between the BM-SC and the MBSF network element.

[0180] It can be understood that the above Figure 3 The network architecture shown in FIG. 4 can also include other possible devices or network elements, such as a UDR network element, a HSS+UDM, a NEF network element, and the like. The HSS+UDM is used to implement the functions of the HSS network element and the UDM network element, and the HSS+UDM can also be referred to as the UDM network element. The NEF network element can be co-located with the MBSF network element, or can also not be co-located with the MBSF network element. When the NEF network element is not co-located with the MBSF network element, the AS can communicate with the MBSF network element through the NEF network element, or the AS can also directly communicate with the MBSF network element through the interface between the AS and the MBSF network element.

[0181] In the network architecture shown in FIG. 4 Figure 3 In the network architecture shown in FIG. 4 Figure 4 A possible flow is described below.

[0182] Figure 4 A flow diagram for transmitting data of a first service in a 4G network and a 5G network provided by an embodiment of the present application is shown in FIG. 4, which can include the following steps. Figure 4

[0183] S401, the AS requests the MBSF network element to transmit data of a first service in a 4G network in an eMBMS transmission mode, and to transmit data of the first service in a 5G network in a 5MBS transmission mode.

[0184] S402, the MBSF network element creates an MBMS bearer of the first service in the 4G network, and creates a multicast session of the first service in the 5G network.

[0185] Here, creating an MBMS bearer of the first service in the 4G network can mean establishing an MB2-U interface, and establishing interfaces from the MBSF network element to the MBMS-GW and from the MBMS-GW to the eNB, and notifying the eNB to establish an MBMS air interface bearer.

[0186] Creating a multicast session of the first service in the 5G network can mean establishing an interface between the AS and the MB-UPF network element. When there is an MBSF network element, an MB2-U interface between the AS and the MBSF network element is established, and an interface between the MBSF network element and the MB-UPF network element is established.​

[0187] S403, AS transmits the data of the first service in the 4G network using eMBMS transmission mode, and transmits the data of the first service in the 5G network using 5MBS transmission mode.

[0188] It should be noted that in a 5G network, before any terminal device joins the multicast session of the first service, the data for the first service is only sent to the MB-UPF network element. In other words, if no terminal device joins the multicast session of the first service, the data will not continue to be sent, i.e., it will not be sent to the access network element or the anchor UPF network element of any PDU session.

[0189] Regarding the aforementioned S401 to S403, with Figure 3 Taking the illustrated network architecture (i.e., the BM-SC and MBSF network elements are co-located) as an example, in one possible implementation, the AS can send a request message to the MBSF network element. This request message requests the transmission of the first service data in the 4G network using eMBMS transmission mode and in the 5G network using 5MBS transmission mode. Correspondingly, after receiving the request message, the MBSF network element can create an MBMS bearer in the 4G network, allowing the AS to transmit the first service data in the 4G network using eMBMS transmission mode. Furthermore, after receiving the request message, the MBSF network element can create a multicast session in the 5G network, allowing the AS to send the first service data to the MB-UPF network element in the 5G network using 5MBS transmission mode.

[0190] In another possible implementation, the AS can send request message 1 to the MBSF network element, requesting the transmission of the first service data in the 4G network using eMBMS transmission mode. Upon receiving request message 1, the MBSF network element can create an MBMS bearer in the 4G network, allowing the AS to transmit the first service data in the 4G network using eMBMS transmission mode. Furthermore, the AS can send request message 2 to the MBSF network element, requesting the transmission of the first service data in the 5G network using 5MBS transmission mode. Upon receiving request message 2, the MBSF network element can create a multicast session in the 5G network, allowing the AS to transmit the first service data to the MB-UPF network element in the 5G network using 5MBS transmission mode.

[0191] It should be noted that when the BM-SC and the MBSF network element are separated, the AS can send a request message 1 to the BM-SC, the request message 1 being used to request to send the data of the first service in the 4G network in the eMBMS transmission mode; and send a request message 2 to the MBSF network element, the request message 2 being used to request to send the data of the first service in the 5G network in the 5MBS transmission mode. Subsequently, the AS can send the data of the first service in the 4G network in the eMBMS transmission mode and send the data of the first service in the 5G network in the 5MBS transmission mode.

[0192] Further, the above process can further include S404a and S405a, or S404b and S405b, or S404c and S405c.

[0193] S404a, the terminal device joins the multicast session of the first service.

[0194] Here, the terminal device can request to join the multicast session of the first service, such as the terminal device can request to join the multicast session of the first service through the signaling of the PDU session. In this way, in the process of joining the terminal device into the multicast session, a shared tunnel from the MB-UPF network element to the access network element can be established, and the access network element can configure wireless resources for the terminal device to receive the data of the first service through the multicast session. It should be understood that this transmission mode is a shared MBS transmission mode. The wireless resources configured by the access network element for the terminal device can be wireless resources corresponding to the PTP mode, that is, wireless resources allocated only for the terminal device to receive the data of the first service, or wireless resources corresponding to the PTM mode, that is, wireless resources allocated for multiple terminal devices (including the terminal device) to receive the data of the first service.

[0195] S405a, the AS sends the data of the first service to the terminal device through the transmission path a, and correspondingly, the terminal device can receive the data of the first service through the transmission path a.

[0196] Here, the transmission path a (i.e., the path corresponding to the shared MBS transmission mode) can be: AS→MB-UPF→gNB→terminal device.

[0197] S404b, the terminal device joins the multicast session of the first service.

[0198] Here, the terminal device can request to join the multicast session of the first service. For example, the terminal device can request to join the multicast session of the first service through signaling of the PDU session. In this method, during the process of adding the terminal device to the multicast session, a tunnel from MB-UPF to PGW-U+UPF can be established, and PGW-U+UPF can map the data of the first service received from the MB-UPF network element to the PDU session of the terminal device, and then send it to the terminal device through the PDU session. It should be understood that this transmission method is a standalone MBS transmission method.

[0199] In S405b, the AS sends the data of the first service to the terminal device through transmission path b, and correspondingly, the terminal device can receive the data of the first service through transmission path b.

[0200] The transmission path b (i.e., the transmission path corresponding to the standalone MBS transmission mode) can be: AS→MB-UPF→PGW-U+UPF→gNB→terminal device.

[0201] S404c, the terminal device enters the service area that supports the transmission of the first service in the 4G network using eMBMS transmission mode.

[0202] In S405c, the AS sends the data of the first service to the terminal device through transmission path c, and correspondingly, the terminal device can receive the data of the first service through transmission path c.

[0203] Here, the transmission path c (i.e., the transmission path corresponding to the eMBMS transmission mode) can be: AS → MBSF network element → MBMS-GW → eNB → terminal equipment.

[0204] It should be noted that: (1) the above Figure 1 , Figure 2 and Figure 3 The network elements described herein can also be referred to as entities or functional entities. For example, an AMF network element can also be referred to as an AMF entity or an AMF functional entity, and an SMF network element can also be referred to as an SMF entity or an SMF functional entity. These network elements can be network components in hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (e.g., a cloud platform). Optionally, the aforementioned network element can be implemented by a single device, multiple devices working together, or it can be a functional module within a single device; this application does not specifically limit this.

[0205] (2) In Figure 1 , Figure 2 or Figure 3In the figure, the letters and numbers near the connection between each network element represent the names of the communication interfaces between each network element, and the meanings of these communication interfaces can be referred to the meanings defined in the relevant standard protocols. It can be understood that the communication interfaces between each network element can also have other names, which are not limited by the embodiments of the present application.

[0206] (3) The network architecture and service scenarios described above are used to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art can know that, as the evolution of the communication system architecture and the emergence of new service scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems. Figure 1 、 Figure 2 and Figure 3 The network architecture and service scenarios described above are used to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art can know that, as the evolution of the communication system architecture and the emergence of new service scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0207] (4) For the terminal device, the access network element, the core network element, the application server and the like in the embodiments of the present application, the device for implementing the function of the terminal device can be the terminal device, or a device capable of supporting the terminal device to implement the function, such as a chip system or a combination device or component capable of implementing the function of the terminal device, which can be installed in the terminal device. In the embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. In the technical solutions provided by the embodiments of the present application, the device for implementing the function of the terminal device is taken as an example to describe the technical solutions provided by the embodiments of the present application.

[0208] Based on the above description, the embodiments of the present application will study the related implementation when the terminal device moves between the first network and the second network. Specifically, the embodiments of the present application provide a communication method for sending data of a first service to a terminal device after the terminal device moves from a second network to a first network or moves from the first network to the second network.

[0209] The communication method provided by the embodiments of the present application is described in detail below in combination with Embodiment One to Embodiment Six. It should be noted that the information 1 involved in Embodiment One to Embodiment Six can be replaced by the first information, the information 2 can be replaced by the second information, the information 4 can be replaced by the third information, the information 5 can be replaced by the fourth information, the information 6 can be replaced by the fifth information, the information 7 can be replaced by the sixth information, the information 8 can be replaced by the seventh information, the information 9 can be replaced by the eighth information, and the information 10 can be replaced by the ninth information. The transmission path 1 involved in Embodiment One to Embodiment Six can be replaced by the first transmission path, the transmission path 4 can be replaced by the second transmission path, and the transmission path 5 can be replaced by the third transmission path. The core network element 1 involved in Embodiment One to Embodiment Six can be replaced by the first core network element, the core network element 2 can be replaced by the second core network element, the core network element 3 can be replaced by the third core network element, the core network element 4 can be replaced by the fourth core network element, the core network element 5 can be replaced by the fifth core network element, the core network element 6 can be replaced by the sixth core network element, and the core network element 7 can be replaced by the seventh core network element.

[0210] Exemplarily, the scenario to which Embodiment One to Embodiment Three are applicable can be as follows: when the terminal device receives the data of the first service in the 5G network in the 5MB S transmission mode, the terminal device is moved from the 5G network to the 4G network. In this scenario, before the terminal device is moved from the 5G network to the 4G network, the terminal device is in the connected state. In this case, the terminal device can be moved from the 5G network to the 4G network by accessing the 4G network through the handover process or by accessing the 4G network through redirection. For details, refer to the description in Embodiment One to Embodiment Three.

[0211] When the terminal device is moved from the 5G network to the 4G network, if the target cell of the terminal device supports the multicast transmission mode (i.e., the eMBMS transmission mode) of the 4G network to transmit the data of the first service, the first service can not be switched to the unicast transmission mode of the 4G network for transmission. In this case, the terminal device can directly receive the data of the first service through the eMBMS transmission mode after accessing the target cell. If the target cell of the terminal device does not support the eMBMS transmission mode to transmit the data of the first service, in order to maintain the continuity of the first service, the data of the first service can be switched to the unicast transmission mode of the 4G network for transmission.

[0212] However, it is currently impossible to determine whether the target cell of the terminal device supports the multicast transmission mode of the 4G network to transmit the data of the first service.

[0213] Based on this, the present application provides embodiments one to three for determining whether the target cell of the terminal device supports the multicast transmission mode of the 4G network to transmit the data of the first service, so that the data of the first service can be sent to the terminal device in a reasonable way after the terminal device moves from the 5G network to the 4G network.

[0214] Embodiment one

[0215] In embodiment one, the network architecture as shown in the figure will be taken as an example to describe a possible implementation process of the communication method. Figure 3

[0216] Figure 5 The flowchart corresponding to the communication method provided by embodiment one of the present application. As shown in the figure, the flowchart can include: Figure 5

[0217] S501, the PGW-C+SMF acquires the service area information of the first service, and the service area information is used to indicate the service area supporting the first service to be transmitted in the 4G network in the first transmission mode (i.e. eMBMS transmission mode).

[0218] Exemplarily, the service area information includes at least one of the following: the identifier of the PLMN corresponding to the service area; the TAI corresponding to the service area; the identifier of the cell corresponding to the service area.

[0219] There can be many implementation ways for the PGW-C+SMF to acquire the service area information of the first service. Two possible implementation ways are described below.

[0220] (1) Implementation way 1

[0221] The core network element 1 can send the service area information of the first service to the PGW-C+SMF, and then the PGW-C+SMF can receive the service area information of the first service. The core network element 1 can include any of the following: MBSF network element, MB-SMF network element, NEF network element, PCF network element, UDM network element, UDR network element.

[0222] ​​Exemplarily, the MBSF network element / NEF network element can receive the play scope information of the first service sent by the AS, and further determine the service area information of the first service according to the play scope information of the first service. Further, for example, the MBSF network element / NEF network element can send the service area information of the first service to the PGW-C+SMF; for another example, the MBSF network element / NEF network element can first send the service area information of the first service to the MB-SMF network element, and then send the service area information of the first service to the PGW-C+SMF by the MB-SMF network element; for another example, the MBSF network element / NEF network element can first send the service area information of the first service to the PCF network element, and then send the service area information of the first service to the PGW-C+SMF by the PCF network element; for another example, the MBSF network element / NEF network element can save the service area information of the first service in the UDR network element / UDM network element, and then send the service area information of the first service to the PGW-C+SMF by the UDR network element / UDM network element; for another example, the MBSF network element / NEF network element can save the service area information of the first service in the UDR network element / UDM network element, and then the MB-SMF network element obtains the service area information of the first service from the UDR network element / UDM network element, and then sends the service area information of the first service to the PGW-C+SMF.

[0223] Exemplarily, after receiving the join request (for requesting to join the multicast session of the first service) sent by the terminal device, the PGW-C+SMF can request the service area information of the first service from the core network element 1, and then can receive the service area information of the first service sent by the core network element 1.

[0224] (2) Implementation manner 2

[0225] The terminal device can send the service area information of the first service to the PGW-C+SMF, and then the PGW-C+SMF can receive the service area information of the first service. Exemplarily, before joining the multicast session of the first service, the terminal device can receive the service announcement of the first service sent by the AS or the MBSF network element, and the service announcement includes the service area information of the first service, and then the terminal device can send the service area information of the first service to the PGW-C+SMF.

[0226] In one example, the terminal device can send the service area information of the first service to the PGW-C+SMF when joining the multicast session of the first service, in which case the service area information of the first service and the join request can be carried in the same message, which can be a PDU session establishment request message or a PDU session modification request message.

[0227] In yet another example, the terminal device can also send the service area information of the first service to the PGW-C+SMF after joining the multicast session of the first service, in which case the service area information of the first service can be carried in a PDU session modification request message.

[0228] S502, the AMF network element sends the information of the target cell of the terminal device to the PGW-C+SMF; correspondingly, the PGW-C+SMF can receive the information of the target cell.

[0229] Exemplarily, the information of the target cell can include the TAI corresponding to the target cell and / or the identifier of the target cell. Before the AMF network element sends the information of the target cell to the PGW-C+SMF, the information of the target cell can be acquired. For example, when the terminal device moves from the 5G network to the 4G network, the source access network element (i.e. the gNB in the 5G network) of the terminal device can send a handover request to the AMF network element, and the handover request includes the information of the target cell. Further, the AMF network element can acquire the information of the target cell from the handover request.

[0230] There can be multiple implementation manners for the AMF network element to send the information of the target cell to the PGW-C+SMF, and two possible implementation manners are described below.

[0231] (1) Implementation manner 1

[0232] The AMF network element can actively send the information of the target cell to the PGW-C+SMF. For example, after the AMF network element acquires the information of the target cell, if it is determined that the terminal device has joined the multicast session of the first service, the first PDU session associated with the first service can be determined, the first PDU session is the PDU session of the terminal device, and a session context request message can be sent to the PGW-C+SMF, the session context request message can include the information of the target cell, and the session context request message is used to request the context of the first PDU session. It should be noted that in other possible embodiments, the AMF network element can not determine whether the terminal device has joined the multicast session of the first service, nor determine the PDU session associated with the first service. The AMF network element can send the information of the target cell to the PGW-C+SMF corresponding to each PDU session that needs to be switched.

[0233] The AMF network element can determine the first PDU session associated with the first service in multiple ways. For example, in the process of adding the terminal device to the multicast session of the first service, the PGW-C+SMF can send the identifier of the multicast session of the first service to the AMF network element through the first PDU session. The identifier of the multicast session of the first service can be an identifier corresponding to the third transmission mode (i.e., the 5MBS transmission mode) of the first service. After receiving the identifier of the multicast session of the first service, the AMF network element can establish an association between the first service and the first PDU session, and then determine the first PDU session associated with the first service according to the association. For another example, the AMF network element can obtain the single network slice selection assistance information (S-NSSAI) and / or data network name (DNN) of the first service, and determine the PDU session corresponding to the S-NSSAI and / or DNN of the first service as the first PDU session associated with the first service. For example, the AMF network element can obtain the S-NSSAI and / or DNN of the first service from the UDM network element.

[0234] In addition, in the implementation manner 1, after obtaining the information of the target cell, the AMF network element can unconditionally send the information of the target cell to the PGW-C+SMF; that is, as long as the AMF network element obtains the information of the target cell, the AMF network element can send the information of the target cell to the PGW-C+SMF. Alternatively, after obtaining the information of the target cell, the AMF network element can conditionally send the information of the target cell to the PGW-C+SMF; that is, after obtaining the information of the target cell, the AMF network element can determine whether a preset condition is met, and if the preset condition is met, the AMF network element can send the information of the target cell to the PGW-C+SMF, and if the preset condition is not met, the AMF network element can no longer send the information of the target cell to the PGW-C+SMF. For example, after obtaining the information of the target cell, the AMF network element can determine whether the first service supports transmission through the 4G network, and if the first service supports transmission through the 4G network, the AMF network element can send the information of the target cell to the PGW-C+SMF, and if the first service does not support transmission through the 4G network, the AMF network element can no longer send the information of the target cell to the PGW-C+SMF. The AMF network element can determine whether the first service supports transmission through the 4G network in multiple ways. For example, the AMF network element can obtain the subscription data of the first service, and then determine whether the first service supports transmission through the 4G network according to the subscription data.

[0235] Implementation manner 2

[0236] The AMF network element can passively send the information of the target cell to the PGW-C+SMF. For example, the AMF network element can send the information of the target cell to the PGW-C+SMF based on a request or indication of the PGW-C+SMF.

[0237] For example, after receiving the handover request sent by the source access network element, the AMF network element can send a session context request message to the PGW-C+SMF, the session context request message being used to request the context of the first PDU session of the terminal device, and the session context request message not including the information of the target cell. Correspondingly, after receiving the session context request message, the PGW-C+SMF can obtain the information of the target cell of the terminal device from the AMF network element. As a possible implementation, the PGW-C+SMF can determine whether the first service supports transmission through the 4G network, if yes, the information of the target cell of the terminal device can be obtained from the AMF network element, and if not, the information of the target cell of the terminal device can no longer be obtained from the AMF network element.

[0238] It should be noted that the PGW-C+SMF can also obtain the service area information of the first service after receiving the information of the target cell, that is, S501 can be executed after S502.

[0239] S503, the PGW-C+SMF determines whether the target cell is in the service area according to the information of the target cell, if the target cell is not in the service area, S504a and S505a are executed, and if the target cell is in the service area, S504b and S505b are executed.

[0240] Here, the PGW-C+SMF can determine whether the target cell is in the service area according to the information of the target cell and the service area information. For example, the information of the target cell includes the TAI corresponding to the target cell (such as TAI-1), and the service area information includes the TAI corresponding to the service area (such as TAI-1, TAI-2, TAI-3), since the TAI corresponding to the service area includes the TAI corresponding to the target cell, it can be determined that the target cell is in the service area.

[0241] It should be noted that if the PGW-C+SMF fails to obtain the information of the target cell from the AMF network element (for example, the AMF network element does not support sending the information of the target cell to the PGW-C+SMF), it can be considered that the target cell is not in the service area.

[0242] S504a, the PGW-C+SMF sends information 1, the information 1 being used to establish a transmission path 1, and the transmission path 1 being used to send the data of the first service to the terminal device in the second transmission mode in the 4G network.

[0243] Here, the transmission path 1 (i.e., the transmission path corresponding to the second transmission mode) can be: AS→MB-UPF network element→PGW-U+UPF→SGW→eNB→terminal device. The unicast bearer between the terminal device and the PGW-U+UPF is included in the transmission path 1, and the information 1 used to establish the transmission path 1 can mean that the information 1 is used to establish the unicast bearer included in the transmission path 1. In an example, the information 1 can include the context of the unicast bearer, such as the QoS information of the unicast bearer, the identifier of the unicast bearer, and the like.

[0244] Before the PGW-C+SMF sends the information 1, the PGW-C+SMF can obtain the information 1. For example, the PGW-C+SMF can obtain the information of the multicast QoS flow of the first service, and then determine the information of the unicast QoS flow of the first service according to the information of the multicast QoS flow of the first service; further, the SMF network element can map the unicast QoS flow of the first service to the unicast bearer, and obtain the identifier of the unicast bearer (such as the identifier of the unicast bearer obtained from the AMF network element), so as to obtain the information 1. Alternatively, the PGW-C+SMF can also directly map the multicast QoS flow of the first service to the unicast bearer, and obtain the identifier of the unicast bearer, so as to obtain the information 1.

[0245] It can be understood that the timing of the PGW-C+SMF obtaining the information 1 is not limited by the embodiments of the present application. For example, the PGW-C+SMF can obtain the information 1 in the process of adding the terminal device to the multicast session of the first service; or the PGW-C+SMF can also obtain the information 1 after determining that the target cell is not in the service area.

[0246] Exemplarily, the PGW-C+SMF sending the information 1 can mean that the PGW-C+SMF sends the information 1 to the AMF network element. For example, the PGW-C+SMF sends a session context response message to the AMF network element, and the session context response message includes the context of the first PDU session, and the context of the first PDU session includes the information 1. Correspondingly, after the AMF network element receives the information 1, the AMF network element can send the information 1 to the MME in the 4G network in the handover process, and then the MME can establish the unicast bearer in the 4G network according to the information 1.

[0247] In addition, if the terminal device receives the data of the first service through the shared MBS transmission mode of the third transmission mode (i.e., the 5MBS transmission mode) of the 5G network before switching to the 4G network, the PGW-C+SMF can also trigger the establishment of a tunnel from the MB-UPF network element to the PGW-U+UPF, and notify the PGW-U+UPF to map the data of the first service received from the MB-UPF network element to the above-mentioned unicast bearer and send it to the terminal device.

[0248] Specifically, in one example, after the terminal device switches to the 4G network, the PGW-C+SMF can receive a session update request message (for example, receive the session update request message from the SGW or the MME); after receiving the session update request message, the PGW-C+SMF can instruct the PGW-U+UPF to map the data of the first service to the above-mentioned unicast bearer and send the data to the terminal device when the MB-UPF network element receives the data of the first service. If the tunnel between the MB-UPF network element and the PGW-U+UPF has not been established, the PGW-C+SMF can also trigger the establishment of the tunnel from the MB-UPF to the PGW-U+UPF.

[0249] S505a, after the terminal device switches to the 4G network, the AS can send the data of the first service to the terminal device through the transmission path 1; correspondingly, the terminal device receives the data of the first service through the transmission path 1.

[0250] S504b, the PGW-C+SMF does not send information 1.

[0251] Here, the PGW-C+SMF does not send information 1 can mean that the PGW-C+SMF can not send information 1 to the AMF network element. For example, the PGW-C+SMF sends a session context response message to the AMF network element, the session context response message includes the context of the first PDU session, and the context of the first PDU session does not include information 1. Since the AMF network element has not received information 1, the AMF network element can not send information 1 to the MME in the 4G network in the switching process, and then the MME can no longer establish a unicast bearer for the terminal device.

[0252] S505b, after the terminal device switches to the 4G network, the AS can send the data of the first service to the terminal device through the transmission path 2; correspondingly, the terminal device receives the data of the first service through the transmission path 2.

[0253] Here, the transmission path 2 (i.e. the transmission path corresponding to the first transmission mode) can be: AS→MBSF network element→MBMS-GW→eNB→terminal device.

[0254] Since the target cell is in the service area, the information broadcasted in the broadcast channel of the target cell can include the TMGI corresponding to the first service and the configuration information of the first service. After the terminal device switches to the target cell, the terminal device can listen to the broadcast channel of the target cell according to the pre-acquired TMGI corresponding to the first service, and then receive the data of the first service through the transmission path 2 according to the configuration information of the first service. The configuration information of the first service can be used to determine the resource carrying the data of the first service. For example, the TMGI corresponding to the first service can be acquired by the terminal device from the AS in advance, or can also be acquired by the terminal device from the MBSF network element in advance, and the specific implementation is not limited.

[0255] For example, since the terminal device can receive the data of the first service through the transmission path 2, the PGW-C+SMF can release or delete the resource in the 5G network for sending the data of the first service to the terminal device. For example, the PGW-C+SMF can delete the multicast information of the first service, for example, delete the identifier of the multicast session of the first service, the information of the multicast QoS flow, and optionally, if there is a unicast QoS flow corresponding to the multicast QoS flow, the PGW-C+SMF can also delete the information of the unicast QoS flow. Further, if the terminal device is the last terminal device in the multicast session of the first service, the PGW-C+SMF can also delete the session between the MB-SMF network element. If the terminal device receives the data of the first service through the separate MBS transmission mode in the third transmission mode before the terminal device switches to the 4G network, the PGW-C+SMF can also delete the configuration of the PGW-U+UPF, so that the PGW-U+UPF stops copying the data of the first service into the tunnel corresponding to the first PDU session for sending; if the terminal device is the last terminal device receiving the data of the first service through the PGW-U+UPF in the separate MBS transmission mode, the PGW-C+SMF can also notify the MB-SMF network element to delete the tunnel from the MB-UPF network element to the PGW-U+UPF.

[0256] By using the above method, the PGW-C+SMF can determine whether the target cell is in the service area according to the service area information of the first service and the information of the target cell of the terminal device, and then perform different processing according to whether the target cell is in the service area. For example, if the target cell is not in the service area, the PGW-C+SMF can send information 1, and then the AS can send the data of the first service to the terminal device in the second transmission mode in the 4G network, and if the target cell is in the service area, the PGW-C+SMF can not send information 1, and then the AS can send the data of the first service to the terminal device in the first transmission mode (i.e., the eMBMS transmission mode) in the 4G network.

[0257] It should be noted that in the process described in Embodiment One, if the target cell is in the service area, the PGW-C+SMF can not send information 1. In other possible implementations, if the target cell is in the service area, the PGW-C+SMF can also send information 1, and then the AS can send the data of the first service to the terminal device in the 4G network in a second transmission mode. The present application embodiment does not limit the related implementation when the target cell is in the service area.

[0258] Embodiment two

[0259] In Embodiment Two, a possible implementation process of the communication method will be described taking the network architecture shown in Figure 3 as an example.

[0260] Figure 6 The flowchart corresponding to the communication method provided in Embodiment Two is shown in Figure 6 . As shown in the figure, the flowchart can include the following steps:

[0261] S601, the AMF network element acquires the service area information of the first service, and the service area information is used to indicate the service area in which the first service is transmitted in the 4G network in a first transmission mode (i.e. eMBMS transmission mode).

[0262] Here, the implementation of the AMF network element acquiring the service area information of the first service can be various, for example, the AMF network element can receive the service area information of the first service from the core network element 2, and the core network element 2 can include any of the following: PGW-C+SMF, MBSF network element, MB-SMF network element, NEF network element, UDM network element, UDR network element.

[0263] Exemplarily, the MBSF network element / NEF network element can receive the broadcast scope information of the first service sent by the AS, and then determine the service area information of the first service according to the broadcast scope information of the first service. Further, for example, the MBSF network element / NEF network element can send the service area information of the first service to the AMF network element; for another example, the MBSF network element / NEF network element can send the service area information of the first service to the PGW-C+SMF, and then send to the AMF network element by the PGW-C+SMF; for another example, the MBSF network element / NEF network element can send the service area information of the first service to the MB-SMF network element, and then send to the AMF network element by the MB-SMF network element; for another example, the MBSF network element / NEF network element can save the service area information of the first service in the UDR network element / UDM network element, and then send to the AMF network element by the UDR network element / UDM network element; for another example, the MBSF network element / NEF network element can save the service area information of the first service in the UDR network element / UDM network element, and the MB-SMF network element obtains the service area information of the first service from the UDR network element / UDM network element, and then sends to the AMF network element.

[0264] S602, the AMF network element determines whether the target cell is in the service area according to the information of the target cell, if the target cell is not in the service area, S603a to S606a are executed, if the target cell of the terminal device is in the service area, S603b to S605b are executed, or S603c to S605c are executed.

[0265] Here, the AMF network element can obtain the information of the target cell, and then determine whether the target cell is in the service area according to the information of the target cell and the service area information. For example, when the terminal device moves from the 5G network to the 4G network, the source access network element (i.e. gNB in the 5G network) of the terminal device can send a handover request to the AMF network element, and the handover request includes the information of the target cell. Then, the AMF network element can obtain the information of the target cell from the handover request.

[0266] S603a, the AMF network element sends a session context request message to the PGW-C+SMF, and the session context request message includes information 2, which is used to indicate that the data of the first service is sent to the terminal device in the second transmission mode in the 4G network.

[0267] Exemplarily, if the AMF network element determines that the terminal device joins the multicast session of the first service, the AMF network element can determine a first PDU session associated with the first service, the first PDU session being a PDU session of the terminal device, and then send a session context request message to the PGW-C+SMF, the session context request message being used to request a context of the first PDU session. The related implementation of the AMF network element determining the first PDU session associated with the first service can be referred to the description in Embodiment 1.

[0268] It should be noted that the information 2 is used to indicate that the data of the first service is sent to the terminal device in the 4G network in the second transmission mode, and can be replaced by other possible descriptions, such as the information 2 can be replaced by the information 2 being used to indicate that the target cell of the terminal device is not in the service area, or the information 2 is used to indicate that the information 1 is acquired, which is not limited in detail.

[0269] S604a, the PGW-C+SMF receives the session context request message, and according to the information 2, sends the context of the first PDU session to the AMF network element, the context of the first PDU session including the information 1.

[0270] S605a, the AMF network element sends the information 1, the information 1 being used to establish a transmission path 1, the transmission path 1 being used to send the data of the first service to the terminal device in the 4G network in the second transmission mode. The transmission path 1 can be referred to the description in Embodiment 1.

[0271] Exemplarily, the AMF network element sending the information 1 can mean that the AMF network element sends the information 1 to the MME in the 4G network in the handover process, and then the MME can establish the unicast bearer included in the transmission path 1 in the 4G network according to the information 1.

[0272] S606a, after the terminal device switches to the 4G network, the AS sends the data of the first service to the terminal device through the transmission path 1; correspondingly, the terminal device receives the data of the first service through the transmission path 1.

[0273] S603b, the AMF network element sends a session context request message to the PGW-C+SMF, the session context request message not including the information 2 or the session context request message including the information 3, the information 3 being used to indicate that the data of the first service is sent to the terminal device in the 4G network in the first transmission mode (i.e. the eMBMS transmission mode).

[0274] It should be noted that the information 3 is used to indicate that the data of the first service is sent to the terminal device in the 4G network in the first transmission mode, and can be replaced by other possible descriptions, such as the information 3 can be replaced by the information 3 being used to indicate that the target cell of the terminal device is in the service area, or the information 3 is used to indicate that the information 1 is not acquired, which is not limited in detail.

[0275] S604b, the PGW-C+SMF sends the context of the first PDU session to the AMF network element, and the context of the first PDU session does not include information 1; correspondingly, the AMF network element can receive the context of the first PDU session.

[0276] In this case, since the AMF network element does not receive information 1, the AMF network element can not send information 1. The AMF network element not sending information 1 can mean that the AMF does not send information 1 to the MME in the 4G network in the handover process, and then the MME can no longer establish a unicast bearer for the terminal device.

[0277] Exemplarily, the PGW-C+SMF can release or delete the resources in the 5G network for sending data of the first service to the terminal device, which can be referred to the description in Embodiment One.

[0278] S605b, after the terminal device switches to the 4G network, the AS sends data of the first service to the terminal device through transmission path 2; correspondingly, the terminal device receives data of the first service through transmission path 2. The transmission path 2 (i.e. the transmission path corresponding to the first transmission mode) can be referred to the description in Embodiment One.

[0279] It should be noted that in the above described process, if the AMF network element determines that the target cell is not in the service area, the session context request message sent by the AMF network element to the PGW-C+SMF can carry information 2, and then the PGW-C+SMF can send information 1 to the AMF network element; after receiving information 1, the AMF network element can send information 1. Or, if the AMF network element determines that the target cell is in the service area, the session context request message sent by the AMF network element to the PGW-C+SMF can not carry information 2 or carry information 3, and then the PGW-C+SMF can not send information 1 to the AMF network element; since the AMF network element does not receive information 1, the AMF network element can not send information 1. In other possible embodiments, the AMF network element can send the session context request message to the PGW-C+SMF, and the PGW-C+SMF receives the session context request message, and then sends information 1 to the AMF network element; after receiving information 1, the AMF network element can decide whether to send information 1 according to whether the target cell is in the service area.

[0280] S603c, the AMF network element sends information 4 to the source access network element (i.e. gNB in the 5G network) of the terminal device, and information 4 is used to redirect the terminal device to the target cell.

[0281] S604c, the gNB redirects the terminal device to the target cell.

[0282] Here, the gNB can inform the terminal device to access the target cell, and accordingly, the terminal device can access the 4G network through the target cell. Further, in the process of the terminal accessing the 4G network (for example, accessing the 4G network through a tracking area update process), the MME requests the context of the terminal device from the AMF network element, and then the AMF network element can send a session context request message to the PGW-C+SMF according to the request of the MME, and the session context request message can not carry information 2 or carry information 3, and then the PGW-C+SMF can not send information 1 to the AMF network element, and the AMF network element can also not send information 1 to the MME, so that the unicast bearer can not be established in the 4G network.

[0283] Exemplarily, after receiving the session context request message, the PGW-C+SMF can release or delete the resources in the 5G network for sending the first service to the terminal device, which can be referred to the description in Embodiment One.

[0284] S605c, the AS sends data of the first service to the terminal device through the transmission path 2; accordingly, the terminal device receives the data of the first service through the transmission path 2.

[0285] Here, since the target cell is in the service area, the information broadcast in the broadcast channel of the target cell can include the TMGI corresponding to the first service and the configuration information of the first service. After the terminal device accesses the target cell, it can listen to the broadcast channel of the target cell according to the pre-acquired TMGI corresponding to the first service, and then receive the data of the first service through the transmission path 2 according to the configuration information of the first service.

[0286] By using the above method, the AMF network element can determine whether the target cell is in the service area according to the service area information of the first service and the information of the target cell of the terminal device, and then perform different processing according to whether the target cell is in the service area. For example, if the target cell is not in the service area, the AMF network element can send information 1, and then the AS can send data of the first service to the terminal device in the 4G network in the second transmission mode, and if the target cell is in the service area, the AMF network element can not send information 1, and then the AS can send data of the first service to the terminal device in the 4G network in the first transmission mode (i.e. eMBMS transmission mode).

[0287] Embodiment three

[0288] In Embodiment Three, a possible implementation process of the communication method will be described taking the network architecture shown in Figure 3 as an example.

[0289] Figure 7 The flowchart corresponding to the communication method provided in Embodiment Three of the present application. As shown inFigure 7 As shown, the flow can include:

[0290] S701, the source access network element of the terminal device (i.e., gNB in the 5G network) acquires the service area information of the first service, and the service area information is used to indicate the service area in which the first service is transmitted in the first transmission mode (i.e., eMBMS transmission mode) in the 4G network.

[0291] Here, the gNB can acquire the service area information of the first service in multiple ways. Two possible implementation manners are described below.

[0292] (1) Implementation manner 1

[0293] The core network element 3 can send the service area information of the first service to the gNB, and then the gNB can receive the service area information of the first service. The core network element 3 can include any of the following: PGW-C+SMF, AMF network element, and MB-SMF network element.

[0294] For example, the PGW-C+SMF or the AMF network element can send the service area information of the first service to the gNB when requesting the gNB to add the terminal device to the multicast session of the first service. For another example, the MB-SMF can send the service area information of the first service to the gNB when the gNB establishes the multicast session of the first service. Specifically, after receiving the request to add the terminal device to the multicast session of the first service, the gNB can send a request message to the MB-SMF to establish the multicast session of the first service, and then the MB-SMF can send the service area information of the first service to the gNB through a response message. The implementation of the core network element 3 acquiring the service area information of the first service can refer to the description in Embodiment 1 or Embodiment 2.

[0295] For example, when the AMF network element sends the service area information of the first service to the gNB, the AMF can first crop the service area information of the first service to obtain cropped service area information, and send the cropped service area information to the gNB. The cropped service area information can be used to indicate a first service area in which the first service is supported to be transmitted in the eMBMS transmission mode in the 4G network, and the first service area can be an area adjacent to the gNB in the service area. In this way, the size of the information sent to the gNB can be reduced, thereby saving transmission resources.

[0296] (2) Implementation manner 2

[0297] The terminal device can send the service area information of the first service to the gNB, and the gNB can receive the service area information of the first service. For example, the terminal device can send a radio resource control (RRC) message to the gNB, and the RRC message includes the service area information of the first service.

[0298] In S702, the gNB determines whether the target cell of the terminal device is in the service area. If the target cell is not in the service area, S703a-S704a are performed. If the target cell is in the service area, S703b-S704b are performed, or S703c-S704c are performed.

[0299] In S703a, the gNB sends information 5, which is used to instruct the terminal device to send the data of the first service in the second transmission mode in the 4G network, or information 5 is used to instruct the 4G network to allocate radio resources for the first service, and the radio resources are used to send the data of the first service in the second transmission mode in the 4G network to the terminal device, or information 5 is used to instruct to switch the first service to the 4G network (for example, it can be used to instruct to switch the first service to the 4G network in the switching process).

[0300] In a possible implementation, the gNB can send information 5 to the AMF network element (for example, carried in the switching request), and after the AMF network element receives the information 5, the AMF network element can obtain information 2 according to the information 5 (information 2 can refer to the description in the above embodiment two), and send a session context request message to the PGW-C+SMF, and the session context request message carries information 2. Then the PGW-C+SMF can send information 1 to the AMF network element. After the AMF network element receives the information 1, the AMF network element can send the information 1 to the MME in the 4G network in the switching process, and then the MME can establish the unicast bearer included in the transmission path 1 in the 4G network according to the information 1.

[0301] In another possible implementation, the gNB can send information 5 to the PGW-C+SMF through the AMF network element (in this case, the AMF network element only forwards the information 5 and does not analyze the information 5), for example, the information 5 can be carried in the N2 SM message. Then, after the PGW-C+SMF receives the session context request message sent by the AMF network element (the session context request message includes the information 5), the PGW-C+SMF can send information 1 to the AMF network element according to the information 5. After the AMF network element receives the information 1, the AMF network element can send the information 1 to the MME in the 4G network in the switching process, and then the MME can establish the unicast bearer included in the transmission path 1 in the 4G network according to the information 1.

[0302] Exemplarily, the information 5 can comprise an identification of the multicast session of the first service and / or indication information (such as the indication information can indicate the second transmission manner of the 4G network). For example, when the first PDU session is only associated with the first service, the information 5 can comprise the indication information, but not the identification of the multicast session of the first service.

[0303] S704a, after the terminal device switches to the 4G network, the AS sends data of the first service to the terminal device through the transmission path 1; correspondingly, the terminal device receives the data of the first service through the transmission path 1.

[0304] S703b, the gNB sends the information 6, the information 6 is used for sending data of the first service to the terminal device in the first transmission manner (i.e. the eMBMS transmission manner) in the 4G network, or the information 6 is used for indicating that no radio resource is allocated for the first service in the 4G network, the radio resource is used for sending data of the first service to the terminal device in the second transmission manner in the 4G network, or the information 6 is used for indicating that the first service is not switched to the 4G network (such as can be used for indicating that the first service is not switched to the 4G network in the switching process).

[0305] In a possible implementation, the gNB can send the information 6 to the AMF network element (such as carried in the switching request), after the AMF network element receives the information 6, the AMF network element can obtain the information 3 according to the information 6, and send a session context request message to the PGW-C+SMF, the session context request message carries the information 3, and then the PGW-C+SMF can not send the information 1 to the AMF network element. Since the AMF network element does not receive the information 1, the AMF network element can not send the information 1 to the MME in the 4G network in the switching process, and then the MME can not establish the unicast bearer included in the transmission path 1 in the 4G network.

[0306] In another possible implementation, the gNB can send the information 6 to the PGW-C+SMF through the AMF network element (in this case, the AMF network element plays a forwarding role and can not analyze the information 6), such as the information 6 can be carried in the N2 SM message. Then, after the PGW-C+SMF receives the session context request message sent by the AMF network element (the session context request message includes the information 5), the PGW-C+SMF can not send the information 1 to the AMF network element according to the information 6. Since the AMF network element does not receive the information 1, the AMF network element can not send the information 1 to the MME in the 4G network in the switching process, and then the MME can not establish the unicast bearer included in the transmission path 1 in the 4G network.

[0307] For example, information 6 may include an identifier and / or indication information of the multicast session of the first service (e.g., the indication information may indicate the first transmission mode of the 4G network). For instance, when the first PDU session is only associated with the first service, information 6 may include indication information but not the identifier of the multicast session of the first service.

[0308] For example, in the two implementation methods described above, PGW-C+SMF can also release or delete the resources in the 5G network used to send data for the first service to the terminal device, as described in Embodiment 1.

[0309] In S704b, after the terminal device switches to the 4G network, the AS sends the data of the first service to the terminal device through transmission path 2; correspondingly, the terminal device receives the data of the first service through transmission path 2.

[0310] S703c, gNB redirects terminal devices to the target cell.

[0311] For example, the relevant implementation of S703c can be found in the description of S604c in Embodiment 2.

[0312] S704c, AS sends the data of the first service to the terminal device through transmission path 2; correspondingly, the terminal device receives the data of the first service through transmission path 2.

[0313] Using the above method, the source access network element of the terminal device can determine whether the target cell is within the service area based on the service area information of the first service and the target cell information of the terminal device, and then perform different processing depending on whether the target cell is within the service area. For example, if the target cell is not within the service area, the source access network element can send information 5, and then the AS can send the data of the first service to the terminal device in the second transmission mode on the 4G network. If the target cell is within the service area, the source access network element can redirect the terminal device to the target cell, or send information 6, and then the AS can send the data of the first service to the terminal device in the first transmission mode (i.e., eMBMS transmission mode) on the 4G network.

[0314] The scenarios to which Examples 4 and 5 are applicable can be, for example, in Figure 3 In the illustrated network architecture (coexistence of 4G and 5G networks), when a terminal device moves from a 4G network to a 5G network, it can be in a connected state before the move, allowing it to access the 5G network via a handover process; alternatively, it can be in an idle state before the move, allowing it to access the 5G network from the idle state. For example, in... Figure 2In the network architecture, the terminal device can access the 5G network for the first time.

[0315] When the terminal device accesses the 5G network, since the gNB does not broadcast the TMGI of the first service and the configuration information of the first service (the eNB in the 4G network can broadcast the TMGI of the first service and the configuration information of the first service), the terminal device needs to join the multicast session of the first service to obtain the configuration information of the first service, and then receive the data of the first service according to the configuration information of the first service.

[0316] However, since there can be some PLMNs in the 5G network that do not support transmitting the data of the first service in the 5MBS transmission mode, but the terminal device does not know whether the currently accessed PLMN supports transmitting the data of the first service in the 5MBS transmission mode, so that the terminal device cannot decide whether to join the multicast session of the first service.

[0317] Based on this, embodiments four and five are provided to determine whether the currently accessed PLMN of the terminal device supports transmitting the data of the first service in the 5MBS transmission mode, so that the data of the first service can be transmitted to the terminal device in a reasonable manner after the terminal device accesses the 5G network.

[0318] Embodiment four

[0319] In the fourth embodiment, the data of the first service is transmitted to the terminal device in the 5MBS transmission mode. Figure 3 Taking the network architecture as an example, a possible implementation process of the communication method is described. It should be noted that the fourth embodiment can also be applied to the network architecture shown in Figure 2 .

[0320] Figure 8 A flowchart corresponding to the communication method provided by the fourth embodiment of the present application is shown in FIG. 8. As shown in Figure 8 , the flowchart can include the following steps.

[0321] S801, the terminal device obtains information 7, and the information 7 is used to indicate a network supporting transmitting the data of the first service in a third transmission mode (i.e., the 5MBS transmission mode).

[0322] Exemplarily, the information 7 can include the identification of one or more networks, and the one or more networks support transmitting the data of the first service in the 5MBS transmission mode. Wherein, the one or more networks can be one or more PLMNs in the 5G network, and the one or more PLMNs include the first PLMN. Optionally, the information 7 can also include the DNN and / or S-NSSAI corresponding to each of the one or more networks.

[0323] There are multiple ways for the terminal device to obtain information 7. For example, the terminal device can receive the service announcement of the first service sent by the AS or MBSF network element, which includes information 7.

[0324] S802 is the first PLMN for terminal devices to access the 5G network.

[0325] Here, the first PLMN for terminal devices to access the 5G network can include the following scenarios. Scenario 1, for example, in... Figure 3 In the illustrated network architecture (where 4G and 5G networks coexist), a terminal device moves from a 4G network to a 5G network. Before moving from the 4G network to the 5G network, the terminal device can be in a connected state, and thus the terminal device can be the first PLMN accessing the 5G network through a handover process; or, before moving from the 4G network to the 5G network, the terminal device can be in an idle state, and thus the terminal device can be the first PLMN accessing the 5G network from the idle state. Scenario 2, for example, in... Figure 2 In the illustrated network architecture, the terminal device first accesses the 5G network through the first PLMN.

[0326] S803, the terminal device sends a join request to a network element (such as PGW-C+SMF) in the first PLMN according to information 7. The join request is used to request to join the multicast session of the first service, or the join request is used to request to send the data of the first service to the terminal device in the second network in 5MBS transmission mode.

[0327] For example, a terminal device can send an join request to a network element in a first PLMN through its first PDU session. The DNN and / or S-NSSAI corresponding to the first PDU session are the same as the DNN and / or S-NSSAI corresponding to the first PLMN. The terminal device can determine the first PDU session based on the DNN and / or S-NSSAI corresponding to the first PLMN.

[0328] S804, AS sends the data of the first service to the terminal device through transmission path 3 (i.e., the transmission path corresponding to the third transmission mode); correspondingly, the terminal device receives the data of the first service through transmission path 3.

[0329] Here, if the gNB accessed by the terminal device supports 5G MBS, the terminal device is sent with the data of the first service in a shared MBS transmission mode in the third transmission mode, and the corresponding transmission path 3 can be: AS→MB-UPF→gNB→terminal device. If the gNB accessed by the terminal device does not support 5G MBS, the terminal device is sent with the data of the first service in a separate MBS transmission mode in the third transmission mode, and the corresponding transmission path 3 can be: AS→MB-UPF→PGW-U+UPF→gNB→terminal device.

[0330] By using the above method, the terminal device can determine whether the network accessed by the terminal device supports transmitting the data of the first service in a 5G MBS transmission mode according to the information 7. If it supports, the terminal device can send a join request to join the multicast session of the first service. If it does not support, the terminal device can not send a join request, so that after the terminal device accesses the 5G network, it can determine whether to send a join request by the above judgment, so as to receive the data of the first service in a reasonable way.

[0331] Embodiment five

[0332] In embodiment five, the network architecture as shown in Figure 3 will be taken as an example to describe a possible implementation process of the communication method. It should be noted that embodiment five can also be applicable to the network architecture as shown in Figure 2 .

[0333] Figure 9 The flowchart corresponding to the communication method provided by embodiment five of the present application. As Figure 9 shown, the flowchart can include:

[0334] S901, the MBSF network element or the AS sends a first subscription request to the core network element 4, and the first subscription request is used to request the core network element 4 to send a first notification message after the terminal device accesses the 5G network.

[0335] Here, the first subscription request can include the identifier of the terminal device, and the identifier of the terminal device can be the IP address of the terminal device or the generic public subscription identifier (GPSI).

[0336] Exemplarily, in the network architecture as shown in Figure 3 , the core network element 4 can be an AMF network element, a PGW-C+SMF, or a PCF network element. In the network architecture as shown in Figure 2In the illustrated network architecture, core network element 4 can be an AMF, SMF, or PCF element. For example, an MBSF element or AS can send a first subscription request message to core network element 4 through a NEF element.

[0337] For example, taking the AS as an example, after determining that the terminal device needs to receive the data of the first service, the AS can send a first subscription request to the core network element 4. For instance, the terminal device can send a service request to the AS, which requests to receive the data of the first service. After receiving the service request, the AS can determine that the terminal device needs to receive the data of the first service. Furthermore, the terminal device can indicate its first capability information to the AS, i.e., whether it supports access to the 4G network and / or 5G network. The AS can send the first subscription request based on the terminal's first capability information. For example, if the terminal device's first capability information indicates that the terminal device supports access to the 5G network, the AS can send the first subscription request; if the terminal device's first capability information indicates that the terminal device does not support access to the 5G network, the AS may not send the first subscription request.

[0338] There are several ways for a terminal device to send a service request to an AS. For example, a terminal device can send a service request to an AS through its first session. The first session can be a PDU session or a PDN connection of the terminal device.

[0339] S902, terminal devices access 5G networks.

[0340] Here, terminal devices accessing the 5G network can include the following scenarios. Scenario 1, for example, in... Figure 3 In the illustrated network architecture (where 4G and 5G networks coexist), when a terminal device moves from a 4G network to a 5G network, the terminal device can be in a connected state before moving from the 4G network to the 5G network, and thus the terminal device can access the 5G network through a handover process; or, before moving from the 4G network to the 5G network, the terminal device can be in an idle state, and thus the terminal device can access the 5G network from the idle state. Scenario 2, for example, in... Figure 2 In the illustrated network architecture, the terminal device is accessing the 5G network for the first time.

[0341] It should be noted that S901 can be executed before S902, or S901 can be executed after S902, without any specific limitation.

[0342] S903, core network element 4 sends a first notification message to MBSF network element or AS. The first notification message is used to notify the terminal device to access the 5G network; correspondingly, MBSF network element or AS can receive the first notification message.

[0343] For example, the terminal device accesses the second PLMN of the 5G network, and the first notification message can include an identifier of the second PLMN.

[0344] It should be noted that if S902 is executed before S901, S903 can be a response message of S901, that is, the AS is notified in the response message of the first subscription request that the terminal device accesses the second PLMN of the 5G network.

[0345] S904, the MBSF network element or the AS sends information 8 to the core network element 5, and the information 8 is used to indicate that the data of the first service is sent to the terminal device in a third transmission mode (5MBS transmission mode) in the 5G network. For example, the information 8 can include an identifier of a multicast session of the first service.

[0346] Here, after receiving the first notification message, the MBSF network element or the AS can determine whether the second PLMN supports sending the data of the first service in the 5MBS transmission mode according to the identifier of the second PLMN. If it supports, the MBSF network element or the AS can send the information 8 to the core network element 5, and after receiving the information 8, the core network element 5 can add the terminal device to the multicast session of the first service; if it does not support, the MBSF network element or the AS can not instruct to add the terminal device to the multicast session of the first service.

[0347] Exemplarily, the core network element 5 can be a PCF network element or an MB-SMF network element or an NEF network element or an MBSF network element. Taking the AS as an example, in one example, the AS can send the information 8 to the core network element 5 through the NEF network element. In another example, the AS can send the information 8 to the core network element 5 through an application policy session or an application function session (i.e. AF session) corresponding to a PDU session associated with the first service.

[0348] Exemplarily, after receiving the information 8 from the AS, the core network element 5 can notify the SMF network element (or PGW-C+SMF) corresponding to the PDU session associated with the first service to add the terminal device to the multicast session of the first service. (1) When the AS sends the information 8 to the core network element 5 through the application policy session corresponding to the PDU session associated with the first service, the core network element 5 is a PCF network element, at this time, the PCF network element can notify the SMF network element corresponding to the PDU session through the application policy session to add the terminal device to the multicast session of the first service. (2) When the AS sends the information 8 to the core network element 5 through the NEF, the information 8 can carry the information of the terminal device, and the core network element 5 can be a PCF network element or an SMF network element. For example, the information of the terminal device is the IP address of the terminal device, and the NEF network element can determine the PCF network element or the SMF network element serving the PDU session corresponding to the IP address of the terminal device according to the IP address of the terminal device, and then can notify the SMF network element (directly or through the PCF network element) serving the PDU session to add the terminal device to the multicast session of the first service.

[0349] In addition, when notifying the SMF network element to add the terminal device to the multicast session of the first service, the core network element 5 can send the identifier of the multicast session of the first service to the SMF network element. The process of adding the terminal device to the multicast session of the first service by the SMF network element can refer to the prior art, and will not be described here.

[0350] S905, the AS sends data of the first service to the terminal device through the transmission path 3; correspondingly, the terminal device receives the data of the first service through the transmission path 3.

[0351] Exemplarily, the implementation of S905 can refer to the related description of embodiment four S804.

[0352] By using the above method, the AS can judge whether the network accessed by the terminal device supports transmitting the data of the first service in the 5MBS transmission mode, if yes, the core network element can be instructed to add the terminal device to the multicast session of the first service, if not, the terminal device can not be instructed to add the terminal device to the multicast session of the first service, so that after the terminal device accesses the 5G network, the data of the first service can be transmitted to the terminal device in a reasonable way.

[0353] The scenario applicable to embodiment six can include the scenario applicable to the foregoing embodiments one to three, and can refer to the description hereinbefore.

[0354] Embodiment six

[0355] In embodiment six, a possible implementation process of the communication method will be described by taking the network architecture shown in Figure 3 as an example.

[0356] Figure 10 A flowchart corresponding to the communication method provided in Embodiment Six of the present application is shown in FIG. 10. As shown in FIG. 10, the flowchart can include the following steps. Figure 10

[0357] S1001, the MBSF network element or the AS sends a second subscription request to the core network network element 6, and the second subscription request is used to request the core network network element 6 to send a second notification message after the terminal device accesses the 4G network.

[0358] Here, the second subscription request can include the identifier of the terminal device, and the identifier of the terminal device can be the IP address or the GPSI of the terminal device.

[0359] For example, in the network architecture shown in FIG. 9, the core network network element 6 can be an MME network element, a PGW-C+SMF, or a PCF network element. Figure 3 Figure 1 For example, in the network architecture shown in FIG. 9, the core network network element 6 can be an MME network element or a PCF network element.

[0360] For example, taking the AS as an example, the AS can send the second subscription request to the core network network element 6 after determining that the terminal device needs to receive the data of the first service. For example, the terminal device can send a service request to the AS, and the service request is used to request to receive the data of the first service. Then, the AS can determine that the terminal device needs to receive the data of the first service after receiving the service request. Further, the terminal device can indicate the first capability information of the terminal device to the AS, i.e., whether to support accessing the 4G network and / or the 5G network, and the AS can send the second subscription request based on the first capability information of the terminal. For example, if the first capability information of the terminal device indicates that the terminal device supports accessing the 4G network, the AS can send the second subscription request, and if the first capability information of the terminal device indicates that the terminal device does not support accessing the 4G network, the AS can not send the second subscription request. The way in which the terminal device sends the service request to the AS can refer to the description in Embodiment One.

[0361] S1002, the terminal device accesses the 4G network.

[0362] For example, when the terminal device moves from the 5G network to the 4G network, the terminal device can access the 4G network through an attachment process or a tracking area update process, or the terminal device can also switch to the 4G network through a handover process.

[0363] It should be noted that the above S1001 can be executed before S1002, or S1001 can also be executed after S1002, and the specific implementation is not limited.

[0364] ​​S1003, the core network element 6 sends a second notification message to the MBSF network element or the AS, and the second notification message is used to notify the terminal device to access the 4G network; correspondingly, the MBSF network element or the AS can receive the second notification message.

[0365] It should be noted that if S1002 is executed before S1001, S1003 can be a response message of S1001, that is, the AS is notified in the response message of the second subscription request that the terminal device accesses the 4G network.

[0366] It should be noted that if the terminal device switches to the 4G network through the handover process, the core network element 6 can send the second notification message after the handover is completed, or send the second notification message during the handover process. For example, the second notification message can be sent during the handover preparation stage (for example, the second notification message is sent after the AMF network element receives the handover request message), or the second notification message can be sent during the handover completion stage (for example, the second notification message is sent after the SMF+PGW-C receives the path switching notification). For example, the core network element 6 can be the SMF+PGW-C, and the second notification message can be sent directly to the AS, or the second notification message can be sent to the AS through the PCF network element and / or the NEF network element.

[0367] Alternatively, the core network element 6 can also send the second notification message before the terminal device switches, for example, the second notification message can be sent after it is learned that the terminal device joins the multicast session corresponding to the first service. It should be noted that at this time, the terminal device has not yet switched to the 4G network, but it is possible to switch to the 4G network. In this way, the second notification message can include tracking area list information of the second network currently accessed by the terminal device (i.e., current access location information). When the terminal device moves out of the tracking area list, the second notification message can be sent again to send new tracking area list information. Optionally, the tracking area list of the second network currently accessed by the terminal device can be mapped to the tracking area list of the first network, and the tracking area list of the first network is sent in the second notification message. For example, when the second notification message is sent through the NEF network element, the NEF network element can map the tracking area list of the second network to the tracking area list of the first network. Alternatively, the core network element 6 is the SMF+PGW-C, and the SMF+PGW-C can subscribe to the tracking area list change notification from the AMF network element. When the AMF network element sends the tracking area list to the SMF+PGW-C, the AMF network element can perform the above mapping and send the tracking area list of the first network to the SMF+PGW-C.

[0368] Further, in a possible implementation, the core network element 6 can send a second notification message according to the second capability information of the terminal device. The second capability information can be used to indicate whether the terminal device supports 4G capability (i.e., whether it supports accessing the 4G network) and / or whether it supports eMBMS capability (i.e., whether it supports receiving data in the first transmission mode). For example, when the terminal device supports 4G capability or the terminal device supports eMBMS capability, the core network element 6 can send the second notification message. For example, the terminal device can send the second capability information to the core network element 6, for example, in the PDU session establishment or modification message.

[0369] S1004, the MBSF network element or the AS sends information 9 to the core network element 7, and the information 9 is used to establish a transmission path 4 (a transmission path corresponding to the fifth transmission mode) for sending data of the first service to the terminal device in the 4G network in the fifth transmission mode. For example, the core network element 7 can be an SMF+PGW-C, and the information 9 can be sent to the SMF+PGW-C through an NEF network element and / or a PCF network element, or through the MBSF network element or the MB-SMF network element.

[0370] Here, when the data of the first service is sent in the fifth transmission mode, the destination address of the data packet is the IP address of the terminal device, and the transmission path 4 can be: AS→PGW-U network element→SGW→eNB→terminal device.

[0371] Exemplarily, taking the AS as an example, in a possible implementation, the second notification message can include location information of the terminal device access, and the location information of the terminal device access is used to indicate a location of the terminal device access. For example, the location of the terminal device access includes a cell and / or a tracking area in a 4G network accessed by the terminal device; correspondingly, the location information of the terminal device access can include information of the cell in the 4G network accessed by the terminal device, and / or an identification (tracking area ID, TAI) of the tracking area in the 4G network accessed by the terminal device. Further, after receiving the second notification message, the AS can determine, according to the location information such as the information of the cell, whether the location (such as the cell) supports sending data of the first service in the eMBMS transmission mode (for example, determine whether the cell is in a service area supporting the first service in the eMBMS transmission mode), and if not, send information 9 to the core network element 7, and if yes, the AS can not send the information 9 to the core network element 7. It should be noted that if the core network element 7 receives the information 9 before the terminal device switches to the 4G network (for example, the second notification message is sent before the switching occurs), the core network element 7 can trigger to create a QoS flow for the first service, and when the terminal device switches to the 4G network, the QoS flow is switched to the transmission path 4. Optionally, when the QoS flow is created, the access network element can be instructed not to allocate radio resources for the QoS flow, that is, the access network element can only save the information of the QoS flow.

[0372] For this implementation, it should be noted that in other possible embodiments, after receiving the second notification message, if the AS determines that the location where the terminal device accesses does not support sending the data of the first service in the eMBMS transmission mode, the AS can also send a request information to the BM-SC (i.e., the AS does not send the information 9 to the core network element 7, but sends the request information to the BM-SC), and the request information is used to request to establish the transmission path 5 (the transmission path corresponding to the first transmission mode) for sending the data of the first service to the terminal device in the first transmission mode in the 4G network. For example, the AS can send the request information to the BM-SC, and the request information can include the new service area information of the first service, the new service area information of the first service is used to indicate the new service area of the first service, and the new service area of the first service can include the location where the terminal device accesses. Then, the BM-SC can create an eMBMS bearer for the first service in the new service area, so that the AS sends the data of the first service to the terminal device through the first transmission mode. That is, the service area that supports the first service to be transmitted in the eMBMS transmission mode is not fixed, and when the terminal device accesses the location, the AS can request the BM-SC to create an eMBMS bearer for the first service in the location where the terminal device accesses. After the eMBMS bearer is created, it can be considered that the service area is updated, and the updated service area includes the new service area of the first service. It should be noted that the new service area of the first service includes the location where the terminal device accesses, which can mean that the new service area of the first service is greater than or equal to the location where the terminal device accesses, or in other words, the new service area of the first service completely covers the location where the terminal device accesses.

[0373] In another possible implementation, the second subscription request can include information 10, and the information 10 is used to indicate that the second notification message is sent when the location where the terminal device accesses does not support sending the data of the first service in the eMBMS transmission mode. Then, after receiving the second notification message, the AS can send the information 9 to the core network element 7. For example, the information 10 can also include the service area information that supports the first service to be transmitted in the eMBMS transmission mode, so that the core network element 7 judges whether the location where the terminal device accesses supports sending the data of the first service in the eMBMS transmission mode.

[0374] For this implementation, it should be noted that in other possible embodiments, after receiving the second notification message, the AS can also send a request information to the BM-SC (i.e., the AS does not send the information 9 to the core network element 7, but sends the request information to the BM-SC), and the request information is used to request to establish the transmission path 5 (the transmission path corresponding to the first transmission mode), and specific details can be referred to the description above.

[0375] Exemplarily, the information 9 can comprise service information of the first service when the first service is transmitted in the fifth transmission mode, and the service information can comprise a unicast filtering rule, for example. The information 9 can also comprise QoS information of the first service when the first service is transmitted in the fifth transmission mode. In this way, Figure 3 For example, the core network element 7 can be a PGW-C+SMF, and the MBSF element or the AS can transmit service information to the PGW-C+SMF through the NEF element or the PCF element. For example, the PCF element can determine a policy and charging control (PCC) rule according to the service information, and transmit the PCC rule to the PGW-C+SMF. The PCC rule can comprise a unicast filtering rule. Accordingly, the PGW-C+SMF can establish a unicast bearer according to the PCC rule after receiving the PCC rule, and transmit the unicast filtering rule to the PGW-U element. Then, the PGW-U element can map the data of the first service to the unicast bearer according to the unicast filtering rule after receiving the data of the first service from the AS, and transmit the data of the first service to the terminal device through the unicast bearer. The establishment of the unicast bearer according to the PCC rule can refer to the description of the prior art, and will not be described here.

[0376] It should be noted that when the corresponding unicast bearer has not been established, the data of the first service can be transmitted to the terminal device through a default bearer, so as to avoid data loss, and only a small amount of data can not be guaranteed by QoS.

[0377] S1005, the AS transmits the data of the first service to the terminal device through the transmission path 4, and the destination address of the data packet is the IP address of the terminal device. Correspondingly, the terminal device receives the data of the first service through the transmission path 4.

[0378] By using the above method, the AS can know that the terminal device accesses the 4G network according to the notification message of the core network element. Then, when the cell accessed by the terminal device does not support the transmission of the data of the first service in the eMBMS transmission mode, the AS can transmit the data of the first service to the terminal device through the transmission path corresponding to the fifth transmission mode.

[0379] For the above embodiments one to six, it should be noted that:

[0380] (1) For any one of the information 1 to 10 involved in the embodiments one to six, the message carrying the information is not limited in the embodiments of the present application. Alternatively, one (or some) of the information 1 to 10 can be a message itself.

[0381] (2) The step numbers of each flowchart described in Embodiments 1-6 are only an example of the execution flow, and do not constitute a limitation on the execution sequence of the steps. There is no strict execution sequence between the steps in the embodiments that do not have a time sequence dependency between each other. In addition, the steps shown in each flowchart are not all the steps that must be executed. Some steps can be added or deleted based on the actual needs on the basis of each flowchart.

[0382] (3) The above description focuses on the differences between different embodiments in Embodiments 1-6. Except for the differences, the embodiments can be referred to each other. In addition, in the same embodiment, different implementation manners or different examples can also be referred to each other.

[0383] (4) Embodiments 1-6 can be implemented separately or in combination. For example, Embodiments 1, 2 or 3 can be implemented in combination with Embodiment 4. In this case, when the terminal device moves from the 5G network to the 4G network, the scheme in Embodiments 1, 2 or 3 can be used, and when the terminal device moves from the 4G network to the 5G network, the scheme in Embodiment 4 can be used. For another example, Embodiment 5 can be implemented in combination with Embodiment 6. In this case, when the terminal device moves from the 5G network to the 4G network, the scheme in Embodiment 6 can be used, and when the terminal device moves from the 4G network to the 5G network, the scheme in Embodiment 5 can be used. In addition, in this case, the first subscription request and the second subscription request can be carried in the same message or different messages, which is not limited.

[0384] The above mainly introduces the scheme provided by the embodiments of the present application from the perspective of device interaction. It can be understood that, in order to realize the above functions, the core network element, the access network element, the terminal device or the application server can include the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of the examples described in the embodiments disclosed in the present application, the embodiments of the present application can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is realized in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0385] The embodiments of the present application can divide the functional units of the core network element, the access network element, the terminal device or the application server according to the above method examples. For example, each functional unit can be divided according to each function, or two or more functions can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0386] In the case of using the integrated unit, Figure 11 A possible exemplary block diagram of the apparatus involved in the embodiments of the present application is shown. As shown in Figure 11 The apparatus 1100 can include a processing unit 1102 and a communication unit 1103. The processing unit 1102 is configured to control and manage the actions of the apparatus 1100. The communication unit 1103 is configured to support the communication of the apparatus 1100 with other devices. Optionally, the communication unit 1103, also referred to as a transceiver unit, can include a receiving unit and / or a sending unit, which are configured to perform receiving and sending operations, respectively. Optionally, the apparatus 1100 can further include a storage unit 1101 configured to store the program code and / or data of the apparatus 1100.

[0387] For example, the apparatus 1100 can be the core network element in the above embodiments, or can also be a chip arranged in the core network element. The processing unit 1102 can support the apparatus 1100 to perform the actions of the core network element in the above method examples. Alternatively, the processing unit 1102 mainly performs the internal actions of the core network element in the method examples, and the communication unit 1103 can support the communication between the apparatus 1100 and other devices.

[0388] Specifically, in one embodiment, the processing unit 1102 is configured to obtain service area information of a first service, the service area information being used to indicate a service area supporting the first service to be transmitted in a first network in a first transmission mode; and the communication unit 1103 is configured to: if a target cell of the terminal device is not in the service area, send first information, the first information being used to establish a first transmission path, the first transmission path being used to send data of the first service to the terminal device in a second transmission mode in the first network; or if the target cell is in the service area, not send the first information; wherein the target cell is located in the first network.

[0389] In a possible design, the service area information includes at least one of the following: an identifier of a PLMN corresponding to the service area; a TAI corresponding to the service area; and an identifier of a cell corresponding to the service area.

[0390] In a possible design, the apparatus 1100 can be a session management network element or a chip arranged in the session management network element.

[0391] In a possible design of the method, the communication unit 1103 is further configured to receive the service area information from a first core network element, the first core network element including any one of: a multicast service network element, a multicast session management network element, a network exposure function network element, a policy control network element, a unified data storage network element, and a unified data management network element.

[0392] In a possible design of the method, the communication unit 1103 is specifically configured to receive a first message from the terminal device, the first message including the service area information, and the first message being a PDU session establishment request message or a PDU session modification request message.

[0393] In a possible design of the method, the first message further includes a join request, the join request being used to request that data of the first service be transmitted to the terminal device in a third transmission mode in the second network.

[0394] In a possible design of the method, the processing unit 1102 is further configured to obtain information of the target cell, and determine, according to the information of the target cell, whether the target cell is within the service area.

[0395] In a possible design of the method, the information of the target cell includes a TAI corresponding to the target cell and / or an identifier of the target cell.

[0396] In a possible design of the method, the communication unit 1103 is further configured to receive the information of the target cell from a mobility management network element.

[0397] In a possible design of the method, the information of the target cell is carried in a session context request message from the mobility management network element, the session context request message being used to request a context of a first PDU session of the terminal device, the first PDU session being associated with the first service.

[0398] In a possible design of the method, the processing unit 1102 is further configured to, if the information of the target cell is not carried in the session context request message, determine that the target cell is not within the service area.

[0399] In a possible design, the communication unit 1103 is further configured to receive a session context request message from a mobility management network element, where the session context request message is used to request a context of a first PDU session of the terminal device, and the first PDU session is associated with the first service; and send, to the mobility management network element, the context of the first PDU session according to the session context request message, where the context of the first PDU session does not include the first information.

[0400] In a possible design, the communication unit 1103 is further configured to receive a session context request message from the mobility management network element, where the session context request message is used to request a context of a first PDU session of the terminal device, and the first PDU session is associated with the first service; and send, to the mobility management network element, the context of the first PDU session according to the session context request message, where the context of the first PDU session does not include the first information.

[0401] In a possible design, if the target cell of the terminal device is within the service area, the processing unit 1102 is further configured to release resources in the second network used to send the first service to the terminal device.

[0402] In a possible design, the apparatus 1100 can be a mobility management network element or a chip in a mobility management network element.

[0403] In a possible design, the communication unit 1103 is further configured to receive the service area information from a second core network network element, where the second core network network element includes any of the following: a session management network element, a multicast service network element, a multicast session management network element, a network exposure function network element, a unified data storage network element, and a unified data management network element.

[0404] In a possible design, the processing unit 1102 is further configured to obtain information of the target cell; and determine, according to the information of the target cell, whether the target cell is within the service area.

[0405] In a possible design, the information of the target cell includes a TAI corresponding to the target cell and / or an identifier of the target cell.

[0406] In a possible design, the communication unit 1103 is further configured to receive, from the terminal device, information of the target cell of a source access network network element, where the source access network network element is located in the second network.

[0407] In a possible design, the communication unit 1103 is further configured to receive the first information from a session management network element.

[0408] In a possible design, the communication unit 1103 is further configured to send, to the session management network element, a second message, where the second message is used to obtain the first information.

[0409] In a possible design, the second message comprises second information, where the second information is used to indicate that the data of the first service is sent to the terminal device in the second network in the second transmission mode.

[0410] In a possible design, the second message is a session context request message, where the session context request message is used to request a context of a first PDU session of the terminal device, and the first PDU session is associated with the first service.

[0411] In a possible design, the processing unit 1102 is further configured to determine the first PDU session associated with the first service.

[0412] In a possible design, the processing unit 1102 is specifically configured to: determine, according to an S-NSSAI and / or a DNN of the first service, a PDU session corresponding to the S-NSSAI and / or the DNN as the first PDU session associated with the first service; or establish an association relationship between the first service and the first PDU session by receiving an identifier of the first service from the session management network element through the first PDU session; and determine, according to the association relationship, the first PDU session associated with the first service.

[0413] In a possible design, if the target cell is in the service area, the communication unit 1103 is further configured to send, to a source access network element of the terminal device, third information, where the third information is used to redirect the terminal device to the target cell, and the source access network element is located in the second network.

[0414] For example, the apparatus 1100 can be an access network element in the above embodiments, or can also be a chip arranged in an access network element. The processing unit 1102 can support the apparatus 1100 to perform the actions of the access network element in the above method examples. Alternatively, the processing unit 1102 mainly performs the internal actions of the access network element in the method examples, and the communication unit 1103 can support the communication between the apparatus 1100 and other devices.

[0415] Specifically, in one embodiment, the processing unit 1102 is configured to: obtain service area information of a first service, the service area information being used to indicate a service area in which the first service is supported to be transmitted in a first network in a first transmission mode; and the communication unit 1103 is configured to: if a target cell of the terminal device is not in the service area, send fourth information, the fourth information being used to indicate that a radio resource is allocated for the first service in the first network, the radio resource being used to transmit data of the first service to the terminal device in the first network in a second transmission mode; or if the target cell is in the service area, redirect the terminal device to the target cell, or send fifth information, the fifth information being used to indicate that the radio resource is not allocated for the first service in the first network; wherein the target cell is located in the first network.

[0416] For another example, the apparatus 1100 can be the terminal device in the above embodiments, or can also be a chip arranged in the terminal device. The processing unit 1102 can support the apparatus 1100 to perform the actions of the terminal device in the above method examples. Alternatively, the processing unit 1102 mainly performs the internal actions of the terminal device in the method examples, and the communication unit 1103 can support the communication between the apparatus 1100 and other devices.

[0417] Specifically, in one embodiment, the processing unit 1102 is configured to: obtain sixth information, the sixth information being used to indicate that a second network supports transmitting data of a first service in a third transmission mode; and the communication unit 1103 is configured to: according to the sixth information, send a join request to a network element in the second network, the join request being used to request that the data of the first service is transmitted to a terminal device in the second network in the third transmission mode.

[0418] For another example, the apparatus 1100 can be the application server in the above embodiments, or can also be a chip arranged in the application server. The processing unit 1102 can support the apparatus 1100 to perform the actions of the application server in the above method examples. Alternatively, the processing unit 1102 mainly performs the internal actions of the application server in the method examples, and the communication unit 1103 can support the communication between the apparatus 1100 and other devices.

[0419] Specifically, in one embodiment, the communication unit 1103 is configured to: receive a first notification message, the first notification message being used to notify a terminal device to access a second network, the second network supporting transmitting data of a first service in a third transmission mode; and according to the first notification message, send seventh information, the seventh information being used to indicate that the data of the first service is transmitted to the terminal device in the second network in the third transmission mode.

[0420] In yet another embodiment, the communication unit 1103 is configured to receive a second notification message, the second notification message being used to instruct the terminal device to access the first network; and send, according to the second notification message, eighth information, the eighth information being used to establish a second transmission path, the second transmission path being used to send data of the first service to the terminal device in the fifth transmission mode in the first network; or send, according to the second notification message, request information, the request information being used to request to establish a third transmission path, the third transmission path being used to send data of the first service to the terminal device in the first transmission mode in the first network.

[0421] It should be understood that the division of units in the above apparatus is only a logical functional division, and all or part of the units can be integrated into one physical entity or physically separated in actual implementation. The units in the apparatus can all be implemented in the form of software invoked by a processing element; or all be implemented in the form of hardware; or some units are implemented in the form of software invoked by a processing element and some units are implemented in the form of hardware. For example, each unit can be a separately established processing element, or can be integrated into a chip of the apparatus, and in addition, can be stored in the form of a program in a memory and invoked and executed by a processing element of the apparatus. In addition, all or part of the units can be integrated together or independently implemented. The processing element mentioned herein can be a processor, which can be an integrated circuit with a signal processing capability. In the implementation process, each operation of the above method or each unit can be implemented by an integrated logic circuit of hardware in the processing element or in the form of software invoked by the processing element.

[0422] In one example, the units in any of the above apparatuses can be one or more integrated circuits configured to implement the above method, such as one or more application specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms. In another example, when the units in the apparatus are implemented in the form of a program invoked by a processing element, the processing element can be a processor such as a general purpose central processing unit (CPU) or other processor that can invoke a program. In another example, the units can be integrated together to be implemented in the form of a system-on-a-chip (SOC).

[0423] The above receiving unit is an interface circuit of the apparatus for receiving signals from other apparatuses. For example, when the apparatus is implemented in the form of a chip, the receiving unit is an interface circuit of the chip for receiving signals from other chips or apparatuses. The above sending unit is an interface circuit of the apparatus for sending signals to other apparatuses. For example, when the apparatus is implemented in the form of a chip, the sending unit is an interface circuit of the chip for sending signals to other chips or apparatuses.

[0424] Reference Figure 12 A structural diagram of a core network element is provided for the embodiments of the present application. It can be a session management network element (such as PGW-C+SMF) or a mobility management network element (such as an AMF network element) in the above embodiments, for implementing the operations of the session management network element or the mobility management network element in the above embodiments.

[0425] As Figure 12 shown, the core network element 1200 can include a processor 1201, a memory 1202, and an interface circuit 1203. The processor 1201 can be used to process communication protocols and communication data, and control the communication apparatus. The memory 1202 can be used to store programs and data, and the processor 1201 can execute the methods performed by the core network element in the embodiments of the present application based on the programs. The interface circuit 1203 can be used for the core network element 1200 to communicate with other devices, which can be wired or wireless communication, and the interface circuit can be, for example, a service-oriented communication interface.

[0426] The above memory 1202 can also be external to the core network element 1200, at which time the core network element 1200 can include the interface circuit 1203 and the processor 1201. The above interface circuit 1203 can also be external to the core network element 1200, at which time the core network element 1200 can include the memory 1202 and the processor 1201. When the interface circuit 1203 and the memory 1202 are both external to the core network element 1200, the communication apparatus 1200 can include the processor 1201.

[0427] Figure 12 The core network element shown can implement each process involving the core network element in the above method embodiment. Figure 12 The operations and / or functions of each module in the core network element shown are respectively for implementing the corresponding processes in the above method embodiments. For details, see the description in the above method embodiments, and appropriate detailed descriptions are omitted here.

[0428] Reference Figure 13A structure schematic diagram of an access network element is provided for the embodiments of the present application, which is used to execute the functions of the access network element (such as a source access network element) in the above-mentioned method embodiments. The access network element 130 can include one or more distributed units (DUs) 1301 and one or more centralized units (CUs) 1302. The DU 1301 can include at least one antenna 13011, at least one radio frequency unit 13012, at least one processor 13013 and at least one memory 13014. The DU 1301 is mainly used for the transceiving of radio frequency signals and the conversion between radio frequency signals and baseband signals, and part of baseband processing. The CU 1302 can include at least one processor 13022 and at least one memory 13021.

[0429] The CU 1302 is mainly used for baseband processing, controlling the access network element and the like. The DU 1301 and the CU 1302 can be physically arranged together or physically separated, i.e. a distributed base station. The CU 1302 is the control center of the access network element, which can also be called a processing unit, and is mainly used to complete the baseband processing function. For example, the CU 1302 can be used to control the access network element to execute the operation process of the access network element in the above-mentioned method embodiments.

[0430] In addition, optionally, the access network element 130 can include one or more radio frequency units, one or more DUs and one or more CUs. Among them, the DU can include at least one processor 13013 and at least one memory 13014, the radio frequency unit can include at least one antenna 13011 and at least one radio frequency unit 13012, and the CU can include at least one processor 13022 and at least one memory 13021.

[0431] In one example, the CU1302 can be composed of one or more single boards. Multiple single boards can collectively support a single access indication wireless access network (such as a 5G network), or they can each support wireless access networks with different access standards (such as LTE, 5G, or other networks). The memory 13021 and processor 13022 can serve one or more single boards. That is, each single board can have its own memory and processor, or multiple single boards can share the same memory and processor. Furthermore, each single board can also have necessary circuitry. Similarly, the DU1301 can be composed of one or more single boards. Multiple single boards can collectively support a single access indication wireless access network (such as a 5G network), or they can each support wireless access networks with different access standards (such as LTE, 5G, or other networks). The memory 13014 and processor 13013 can serve one or more single boards. That is, each single board can have its own memory and processor, or multiple single boards can share the same memory and processor. Furthermore, each single board can also have necessary circuitry.

[0432] Figure 13 The access network element shown can implement all the processes involved in the access network element in the above method embodiments. Figure 13 The operations and / or functions of each module of the access network element shown are respectively for implementing the corresponding processes in the above method embodiments. For details, please refer to the descriptions in the above method embodiments; to avoid repetition, detailed descriptions are appropriately omitted here.

[0433] See Figure 14 This is a schematic diagram of the structure of a terminal device provided in an embodiment of this application, used to implement the operation of the terminal device in the above embodiments. Figure 14 As shown, the terminal device includes an antenna 1410, a radio frequency (RF) section 1420, and a signal processing section 1430. The antenna 1410 is connected to the RF section 1420. In the downlink direction, the RF section 1420 receives information sent by the network device through the antenna 1410 and sends the information to the signal processing section 1430 for processing. In the uplink direction, the signal processing section 1430 processes the information from the terminal device and sends it to the RF section 1420. The RF section 1420 processes the information from the terminal device and then sends it to the network device through the antenna 1410.

[0434] The signal processing part 1430 can include a modem subsystem for implementing processing of various protocol layers of data, and can also include a central processing subsystem for implementing processing of an operating system and an application layer of the terminal device, and can further include other subsystems, such as a multimedia subsystem for implementing control of a camera, a screen display, and the like of the terminal device, and a peripheral subsystem for implementing connection with other devices. The modem subsystem can be a separately arranged chip.

[0435] The modem subsystem can include one or more processing elements 1431, such as a master CPU and other integrated circuits. In addition, the modem subsystem can also include a storage element 1432 and an interface circuit 1433. The storage element 1432 is used to store data and programs, but the program used to implement the method performed by the terminal device in the above method can not be stored in the storage element 1432, but in a memory outside the modem subsystem, which is loaded for use when needed. The interface circuit 1433 is used to communicate with other subsystems.

[0436] The modem subsystem can be implemented by a chip including at least one processing element and an interface circuit, wherein the processing element is used to perform each step of any of the methods performed by the terminal device above, and the interface circuit is used to communicate with other devices. In one implementation, the unit for implementing each step of the above method can be implemented by a processing element in the form of a program scheduling, for example, a device for the terminal device includes a processing element and a storage element, and the processing element calls the program stored in the storage element to perform the method performed by the terminal device in the above method embodiment. The storage element can be a storage element on the same chip as the processing element, i.e., an on-chip storage element.

[0437] In another implementation, the program for implementing the method performed by the terminal device in the above method can be in a storage element on a different chip from the processing element, i.e., an off-chip storage element. At this time, the processing element calls or loads the program from the off-chip storage element to the on-chip storage element to call and execute the method performed by the terminal device in the above method embodiment.

[0438] In yet another implementation, the unit for implementing each step of the above method can be configured as one or more processing elements arranged on the modem subsystem, and the processing element here can be an integrated circuit, such as one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these integrated circuits. These integrated circuits can be integrated together to form a chip.

[0439] The units for implementing each step in the above method of the terminal device can be integrated together to realize the above method in the form of a SOC. The SOC chip can be integrated with at least one processing element and a storage element, and the above method executed by the terminal device can be realized in the form of the processing element calling the stored program of the storage element. Alternatively, the chip can be integrated with at least one integrated circuit for realizing the above method executed by the terminal device. Alternatively, in combination with the above implementation manners, the functions of part of the units can be realized in the form of a processing element calling a program, and the functions of part of the units can be realized in the form of an integrated circuit.

[0440] It can be seen that the above apparatus for the terminal device can include at least one processing element and an interface circuit, wherein the at least one processing element is configured to execute any of the methods executed by the terminal device provided in the above method embodiments. The processing element can execute part or all of the steps of the terminal device in the following three ways. First, the processing element calls a program stored in a storage element to execute part or all of the steps of the terminal device. Second, the processing element executes part or all of the steps of the terminal device by means of the integrated logic circuit of the hardware in the processing element in combination with instructions. Third, part or all of the steps of the terminal device can be executed in combination of the first and second ways.

[0441] The processing element herein can be implemented by a processor as described above, and the functions of the processing element can be the same as those of the processing unit described in Figure 11 . For example, the processing element can be a general-purpose processor such as a CPU, and can also be one or more integrated circuits configured to implement the above method, such as one or more ASICs, or one or more microprocessors DSPs, or one or more FPGAs, or the like, or a combination of at least two of these integrated circuit forms. The storage element can be implemented by a memory, and the functions of the storage element can be the same as those of the storage unit described in Figure 11 . For example, the storage element can be a memory, and can also be a general term for a plurality of memories. Figure 11 . For example, the storage element can be a memory, and can also be a general term for a plurality of memories.

[0442] Figure 14 The terminal device shown can implement each process involving the terminal device in the above method embodiments. Figure 14 The operations and / or functions of each module in the terminal device shown are respectively for implementing the corresponding procedures in the above method embodiments. For details, refer to the descriptions in the above method embodiments, and the detailed descriptions are appropriately omitted here.

[0443] Reference Figure 15 The structure of an application server provided in the embodiments of the present application is shown in FIG. 6, which is used to implement the operations of the application server in the above embodiments.

[0444] As shown in Figure 15 The application server 1500 can include a processor 1501, a memory 1502, and an interface circuit 1503. The processor 1501 can be configured to process communication protocols and communication data, and control the communication device. The memory 1502 can be configured to store programs and data, and the processor 1501 can execute the method performed by the application server in the embodiments of the present application based on the programs. The interface circuit 1503 can be configured to enable the application server 1500 to communicate with other devices, which can be wired or wireless communication, and the interface circuit can be, for example, a service-oriented communication interface.

[0445] The above memory 1502 can also be external to the application server 1500, and the application server 1500 can include the interface circuit 1503 and the processor 1501. The above interface circuit 1503 can also be external to the application server 1500, and the application server 1500 can include the memory 1502 and the processor 1501. When the interface circuit 1503 and the memory 1502 are both external to the application server 1500, the communication device 1500 can include the processor 1501.

[0446] Figure 15 The application server shown can implement each process of the application server involved in the above method embodiments. Figure 15 The operations and / or functions of each module in the application server shown are respectively used to implement the corresponding flow in the above method embodiments. For details, please refer to the description in the above method embodiments, and the detailed description is appropriately omitted here.

[0447] The terms "system" and "network" in the embodiments of the present application can be used interchangeably. "At least one" means one or more, and "multiple" means two or more. "And / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, "at least one of A, B, and C" includes A, B, C, AB, AC, BC, or ABC. In addition, unless otherwise specified, the ordinal numbers "first", "second", etc. mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, time sequence, priority, or importance of the multiple objects.

[0448] Those skilled in the art will appreciate that embodiments of the present application can be devised for a variety of other systems which are currently developed or later developed. Therefore, the present application is intended to cover all such modifications and variations of this application that are within the scope of the appended claims and their equivalents. It is intended that each element of claim 1 and 2 is independent of one another. No element of claim 1 and 2, or any other claim, is implied to depend on any other element or limitation of claim 1 and 2 or any other claim except where expressly recited in that claim.

[0449] The present application is described in reference to the flowchart and / or block diagrams of the method, apparatus (system) and computer program product according to this application. It will be understood that each block of the flowchart and / or block diagrams, and combinations of blocks in the flowchart and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart and / or block diagram block or blocks. Figure one one or more functions specified in the flowchart and / or block diagram block or blocks. Figure one means for performing each of the functions specified in the flowchart and / or block diagram block or blocks.

[0450] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart and / or block diagram block or blocks. Figure one one or more functions specified in the flowchart and / or block diagram block or blocks. Figure one means for performing each of the functions specified in the flowchart and / or block diagram block or blocks.

[0451] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart and / or block diagram block or blocks. Figure one one or more functions specified in the flowchart and / or block diagram block or blocks. Figure one means for performing each of the functions specified in the flowchart and / or block diagram block or blocks.

[0452] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described herein.

Claims

1. A communication method characterized by comprising: The method is applied to a first communication device located in a core network, and is applied to terminal equipment moving from a second network to a first network. The method comprises: obtaining service area information of a first service, the service area information being used to indicate a service area supporting the first service to be transmitted in the first network in a first transmission mode; if a target cell of the terminal equipment is not in the service area, sending first information, the first information being used to establish a first transmission path, the first transmission path being used to send data of the first service to the terminal equipment in the first network in a second transmission mode; or if the target cell is in the service area, not sending the first information; wherein the target cell is located in the first network, the first transmission mode is a multicast transmission mode of the first network, and the second transmission mode is a unicast transmission mode of the first network.

2. The method of claim 1, wherein, The service area information comprises at least one of the following: an identifier of a public land mobile network (PLMN) corresponding to the service area; an identifier of a tracking area (TAI) corresponding to the service area; and an identifier of a cell corresponding to the service area.

3. The method of claim 1, wherein, The first communication device is a session management network element or a chip arranged in the session management network element.

4. The method of claim 3, wherein, The obtaining of the service area information of the first service comprises: receiving the service area information from a first core network network element, the first core network network element comprising any one of the following: a multicast service network element, a multicast session management network element, a network exposure function network element, a policy control network element, a unified data storage network element, and a unified data management network element; or receiving the service area information from the terminal equipment.

5. The method of claim 4, wherein, The receiving of the service area information from the terminal equipment comprises: receiving a first message from the terminal equipment, the first message comprising the service area information; wherein the first message is a protocol data unit (PDU) session establishment request message or a PDU session modification request message.

6. The method of claim 5, wherein, The first message further comprises a join request, the join request being used to request data of the first service to be sent to the terminal equipment in a third transmission mode in the second network.

7. The method according to any one of claims 3 to 6, characterized in that, The method further comprises: obtaining information of the target cell; determining whether the target cell is in the service area according to the information of the target cell.

8. The method of claim 7, wherein, The information of the target cell comprises a TAI corresponding to the target cell and / or an identifier of the target cell.

9. The method of claim 7, wherein, The obtaining of the information of the target cell comprises: receiving the information of the target cell from a mobility management network element.

10. The method of claim 9, wherein, The information of the target cell is carried in a session context request message from the mobility management network element, the session context request message being used to request a context of a first PDU session of the terminal equipment, the first PDU session being associated with the first service.

11. The method of claim 10, wherein, The method further comprises: if the information of the target cell is not carried in the session context request message, determining that the target cell is not in the service area.

12. The method according to any one of claims 3 to 6, characterized in that, The sending of the first information comprises: receiving a session context request message from a mobility management network element, the session context request message being used to request a context of a first PDU session of the terminal device, the first PDU session being associated with the first service; sending, to the mobility management network element, the context of the first PDU session according to the session context request message, the context of the first PDU session including the first information.

13. The method according to any one of claims 3 to 6, characterized in that, the not sending the first information includes: receiving a session context request message from a mobility management network element, the session context request message being used to request a context of a first PDU session of the terminal device, the first PDU session being associated with the first service; sending, to the mobility management network element, the context of the first PDU session according to the session context request message, the context of the first PDU session not including the first information.

14. The method of any one of claims 3 to 6, wherein, if the target cell of the terminal device is in the service area, the method further includes: releasing resources in the second network for sending the first service to the terminal device.

15. The method of claim 1, wherein, The first communication device is a mobility management network element or a chip arranged in the mobility management network element.

16. The method of claim 15, wherein, The obtaining the service area information of the first service includes: receiving the service area information from a second core network element, the second core network element including any one of the following: a session management network element, a multicast service network element, a multicast session management network element, a network exposure function network element, a unified data storage network element, and a unified data management network element.

17. The method according to claim 15 or 16, characterized in that, The method further includes: receiving the first information from a session management network element.

18. The method of claim 17, wherein, The method further includes: sending a second message to the session management network element, the second message being used to obtain the first information.

19. The method of claim 18, wherein, The second message includes second information, the second information being used to indicate that data of the first service is sent to the terminal device in the second transmission mode in the first network.

20. The method of claim 18 or 19, wherein, The second message is a session context request message, the session context request message being used to request a context of a first PDU session of the terminal device, the first PDU session being associated with the first service.

21. The method of claim 20, wherein, The method further includes: determining the first PDU session associated with the first service.

22. The method of claim 21, wherein, Determining the first PDU session associated with the first service includes: determining, according to single-network slice selection assistance information (S-NSSAI) and / or a data network name (DNN) of the first service, that a PDU session corresponding to the S-NSSAI and / or the DNN is the first PDU session associated with the first service; or receiving, from the session management network element, an identifier of the first service through the first PDU session, establishing an association relationship between the first service and the first PDU session, and determining the first PDU session associated with the first service according to the association relationship.

23. The method of claim 15 or 16, wherein, if the target cell is in the service area, the method further includes: sending third information to a source access network element of the terminal device, the third information being used for redirecting the terminal device to the target cell, the source access network element being located in the second network.

24. A method of communication, comprising: The method is applicable to a second communication device, which is a terminal device or a chip arranged in the terminal device, and the method comprises: obtaining sixth information, the sixth information being used for indicating that a second network supports transmitting data of a first service in a third transmission mode; the third transmission mode being a multicast transmission mode of the second network; sending a join request to a network element in the second network according to the sixth information, the join request being used for requesting the terminal device to transmit the data of the first service in the third transmission mode in the second network.

25. The method of claim 24, wherein, The sixth information comprises an identifier of one or more networks, the one or more networks comprising the second network, and the one or more networks supporting transmitting the data of the first service in the third transmission mode.

26. The method of claim 25, wherein, The identifier of the one or more networks is an identifier of one or more PLMNs.

27. The method of claim 25, wherein, The sixth information further comprises a DNN and / or an S-NSSAI corresponding to the second network.

28. The method of claim 27, wherein, The method further comprises: sending the join request to the network element in the second network through a first PDU session of the terminal device, the DNN and / or the S-NSSAI corresponding to the first PDU session being the same as the DNN and / or the S-NSSAI corresponding to the second network.

29. The method according to any one of claims 24 to 28, characterized in that, The obtaining of the sixth information of the first service of the terminal device comprises: receiving the sixth information from an application server; or receiving the sixth information from a multicast service network element.

30. A communications device, characterized by The apparatus comprises a module for performing the method of any one of claims 1 to 23.

31. A communications device, characterized by The apparatus comprises a module for performing the method of any one of claims 24 to 29.

32. A communications device, characterized by The apparatus comprises a processor and a memory, the processor and the memory being coupled, and the memory storing a computer program; the processor is configured to invoke the computer program in the memory, so that the communication device performs the method of any one of claims 1 to 23.

33. A communications device, characterized by The apparatus comprises a processor and a memory, the processor and the memory being coupled, and the memory storing a computer program; the processor is configured to invoke the computer program in the memory, so that the communication device performs the method of any one of claims 24 to 29.

34. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions, which, when executed by a computer, implement the method of any one of claims 1 to 23, or the method of any one of claims 24 to 29.

35. A computer program product, characterised in that, When the computer reads and executes the computer program product, the computer is caused to perform the method of any one of claims 1 to 23, or the method of any one of claims 24 to 29.

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