Method, first network device and second network device for groupcast communication

Abstract

The application provides a method, a first network device and a second network device for multicast communication, comprising: the first network device sending first information to the second network device, the first information indicating an association relationship between multicast service information and a first terminal device; the first network device receiving second information from the second network device; the first network device generating a configuration message according to the second information, the configuration message indicating an association relationship between the multicast service information and a first logical channel, the first logical channel being a logical channel of the first terminal device; and the first network device sending the configuration message to the first terminal device. Through the interaction between the first network device and the second network device, the first network device can determine the association relationship between the multicast service information and the logical channel of the terminal device, and can send the association relationship to the terminal device, so that the multicast service can be transmitted through the unicast mode based on the association relationship, and flexible transmission of the multicast service is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication, and more particularly, to a method, a first network device and a second network device for groupcast communication. BACKGROUND

[0002] In order to effectively utilize mobile network resources, the 3rd generation partnership project (3GPP) introduces a multimedia broadcast multicast service (MBMS), which is a technology for transmitting data from a data source to multiple targets, achieving network resource sharing and improving resource utilization, especially air interface resource.

[0003] At present, a multicast unicast hybrid mechanism is discussed. Based on the mechanism, a multicast service can be sent to a terminal device through unicast or multicast.

[0004] In some communication systems, such as a 5G communication system, a network device can be logically divided into a centralized unit (CU) and a distributed unit (DU). Under the CU-DU architecture, how to implement transmission of a multicast service through unicast has not been related technology. SUMMARY

[0005] The present application provides a method, a first network device and a second network device for groupcast communication, which can realize transmission of a multicast service through unicast, thereby realizing flexible transmission of a multicast service.

[0006] In a first aspect, a method for groupcast communication is provided, comprising: a first network device sending first information to a second network device, the first information indicating an association relationship between multicast service information and a first terminal device; the first network device receiving second information from the second network device; the first network device generating a configuration message according to the second information, the configuration message indicating an association relationship between the multicast service information and a first logical channel, the first logical channel being a logical channel of the first terminal device; the first network device sending the configuration message to the first terminal device; the first network device having a packet data convergence protocol layer function, a service data adaptation protocol layer function and a radio resource control layer function, the second network device having a radio link control layer function, a medium access control layer function and a physical layer function.

[0007] It should be understood that in the method, the first network device is a CU, and the second network device is a DU, which can correspond to the same network device (i.e., an access network device or a base station).

[0008] It should be understood that the multicast service information indicates a multicast service. The association relationship between the multicast service information and the first terminal device is also an association relationship between the multicast service and the first terminal device.

[0009] Optionally, the first information can be carried through an interface message (such as a Session Start / Modification Request message) between the first network device and the second network device.

[0010] Optionally, the second information can be carried through an interface message (such as a Session Start / Modification Response message) between the first network device and the second network device.

[0011] According to the method for multicast communication provided in the present application, through the interaction between the first network device and the second network device, the first network device can determine the association relationship between the multicast service information and the logical channel of the terminal device, and can send the association relationship to the terminal device, so that the multicast service can be transmitted through the unicast mode based on the association relationship, and flexible transmission of the multicast service is realized.

[0012] In some implementations of the first aspect, the first information includes the multicast service information and information of the associated first terminal device. The information of the first terminal device indicates the first terminal device.

[0013] In some implementations of the first aspect, the second information indicates the association relationship between the multicast service information and the first logical channel. For example, the configuration message can include the second information.

[0014] In some implementations of the first aspect, the first information indicates the association relationship between the multicast service information and the first terminal device, including that the first information indicates the association relationship between the multicast service information and a first data radio bearer (DRB) of the first terminal device, and the second information indicates the association relationship between the first DRB and the first logical channel of the first terminal device.

[0015] Based on the scheme, the first network device can determine the association between the multicast service information and the first logical channel of the first terminal device.

[0016] In some implementations of the first aspect, the multicast service information comprises one or more of: a multicast area identity, a temporary mobile group identity (TMGI), a session identity, a group radio network temporary identity (G-RNTI).

[0017] For example, for a multimedia broadcast multicast single frequency network (MBSFN) transmission mode, the multicast service information can comprise one or more of: a multicast area identity, a TMGI, a session identity. For a single cell-point to multi-point (SC-PTM) transmission mode, the multicast service information can comprise one or more of: a TMGI, a session identity, a G-RNTI.

[0018] In some implementations of the first aspect, the configuration message is a radio resource control (RRC) reconfiguration message.

[0019] In a second aspect, a method for multicast communication is provided, comprising: receiving, by a second network device, first information from a first network device of a centralized unit, the first information indicating an association relationship between multicast service information and a first terminal device; sending, by the second network device, second information to the first network device, the second information being used for the second network device to determine a configuration message, the configuration message indicating an association relationship between the multicast service information and a first logical channel, the first logical channel being a logical channel of the first terminal device; the first network device having a packet data convergence protocol layer function, a service data adaptation protocol layer function and a radio resource control layer function, the second network device having a radio link control layer function, a medium access control layer function and a physical layer function.

[0020] It should be understood that in the method, the first network device is a CU, and the second network device is a DU, and the two can correspond to the same network device (i.e., an access network device or a base station).

[0021] It should be understood that the multicast service information indicates a multicast service. The association relationship between the multicast service information and the first terminal device is also an association relationship between the multicast service and the first terminal device.

[0022] According to the method for multicast communication provided in the application, the first network device can provide multicast service information and an association relationship of the first terminal device to the second network device, so that the second network device can return second information to the first network device according to the multicast service information and the association relationship of the first terminal device, and the first network device can determine an association relationship of the multicast service information and the first logical channel based on the second information. In this way, by associating the multicast service information and the logical channel of the terminal device, multicast service can be transmitted in a unicast manner, and flexible transmission of multicast service is realized.

[0023] In some implementations of the second aspect, the first information includes the multicast service information and information of the associated first terminal device. The information of the first terminal device indicates the first terminal device.

[0024] In some implementations of the second aspect, the second information indicates an association relationship of the multicast service information and the first logical channel. For example, the configuration message can include the second information.

[0025] In some implementations of the second aspect, the first information indicates an association relationship of the multicast service information and the first terminal device, including that the first information indicates an association relationship of the multicast service information and a first DRB of the first terminal device, and the second information indicates an association relationship of the first DRB and a first logical channel of the first terminal device.

[0026] Based on the scheme, the first network device can determine that the multicast service information is associated with the first logical channel of the first terminal device.

[0027] In some implementations of the first aspect, the multicast service information includes one or more of the following: a multicast area identifier, a TMGI, a session identifier, and a G-RNTI.

[0028] For example, for the MBSFN transmission mode, the multicast service information can include one or more of the following: a multicast area identifier, a TMGI, and a session identifier. For the SC-PTM transmission mode, the multicast service information can include one or more of the following: a TMGI, a session identifier, and a G-RNTI.

[0029] In some implementations of the first aspect, the configuration message is an RRC reconfiguration message.

[0030] In a third aspect, a method for multicast communication is provided, comprising: receiving, by a terminal device, a configuration message from a first network device, the configuration message indicating an association relationship between multicast service information and a first logical channel of the terminal device; and receiving, by the terminal device, multicast service corresponding to the multicast service information on the first logical channel according to the configuration message, the first network device having a packet data convergence protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function.

[0031] According to the method for multicast communication provided in the present application, the first network device can determine the association relationship between the multicast service information and the logical channel of the terminal device, and can send the association relationship to the terminal device, so that the multicast service can be transmitted in a unicast manner based on the association relationship, thereby realizing flexible transmission of the multicast service.

[0032] In some implementations of the third aspect, the multicast service information comprises one or more of the following: a multicast area identifier, a TMGI, a session identifier, and a G-RNTI.

[0033] In some implementations of the third aspect, the configuration message is an RRC reconfiguration message.

[0034] In a fourth aspect, a method for multicast communication is provided, comprising: sending, by a first network device, multicast service information to a second network device; receiving, by the first network device, configuration information of a multicast control channel determined by the second network device according to the multicast service information; generating, by the first network device, system information according to the configuration information, the system information comprising the configuration information; sending, by the first network device, the system information to the second network device; the first network device having a packet data convergence protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function, and the second network device having a radio link control layer function, a medium access control layer function, and a physical layer function.

[0035] It should be understood that in the method, the first network device is a CU, and the second network device is a DU, which can correspond to the same network device (i.e., an access network device or a base station).

[0036] Optionally, the method can further comprise: sending, by the first network device, a multicast service type corresponding to the multicast service information to the second network device. The multicast service type can be MBMS or SC-PTM.

[0037] Optionally, the method can further include: sending, by the first network device, a first network device side transport network layer (TNL) address corresponding to the multicast service information to the second network device. The TNL address includes an IP address and a tunnel endpoint identifier (TEID).

[0038] According to the method for multicast communication provided in the application, the second network device can determine and send configuration information of a multicast control channel corresponding to the multicast service information sent by the first network device to the first network device, and the first network device can generate system information related to multicast according to the configuration information.

[0039] In some implementations of the fourth aspect, the system information is system information block (SIB) 13 or SIB 20.

[0040] In some implementations of the fourth aspect, the multicast service information includes one or more of the following: multicast area identification, temporary mobile group identification, session identification, quality of service (QoS) information.

[0041] In some implementations of the fourth aspect, the configuration information includes one or more of the following: repetition period of the multicast control channel, offset of the multicast control channel, modification period of the multicast control channel, subframe allocation information of the multicast control channel, MBSFN area configuration information, notification indication, and non-MBSFN area length.

[0042] In some implementations of the fourth aspect, the first network device sends the multicast service information to the second network device, including: the first network device sends a session start request message including the multicast service information to the second network device; or the first network device sends a session modification request message including the multicast service information to the second network device.

[0043] In a fifth aspect, a method for multicast communication is provided, comprising: receiving, by a second network device, multicast service information from a first network device; determining, by the second network device, configuration information of a multicast control channel according to the multicast service information; sending, by the second network device, the configuration information to the first network device; receiving, by the second network device, system information from the first network device, the system information comprising the configuration information; broadcasting, by the second network device, the system information; the first network device having a packet data convergence protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function, and the second network device having a radio link control layer function, a medium access control layer function, and a physical layer function.

[0044] It should be understood that in the method, the first network device is a CU, and the second network device is a DU, and the two can correspond to the same network device (i.e., an access network device or a base station).

[0045] According to the method for multicast communication provided in the present application, the second network device can determine and send configuration information of a corresponding multicast control channel to the first network device according to multicast service information sent by the first network device, and the first network device can generate system information related to multicast according to the configuration information.

[0046] In some implementations of the fifth aspect, the system information is SIB13 or SIB20.

[0047] In some implementations of the fifth aspect, the multicast service information comprises one or more of the following: multicast area identification, temporary mobile group identification, session identification, QoS information.

[0048] In some implementations of the fifth aspect, the configuration information comprises one or more of the following: repetition period of the multicast control channel, offset of the multicast control channel, modification period of the multicast control channel, subframe allocation information of the multicast control channel, MBSFN area configuration information, notification indication, non-MBSFN area length.

[0049] In some implementations of the fifth aspect, the receiving, by the second network device, multicast service information from the first network device comprises: receiving, by the second network device, a session start request message from the first network device, the session start request message comprising the multicast service information; or receiving, by the second network device, a session modification request message from the first network device, the session modification request message comprising the multicast service information.

[0050] In a sixth aspect, a method for multicast communication is provided, which includes: receiving, by an integrated access and backhaul (IAB) node, at least one multicast service information from a first network device, the at least one multicast service information indicating at least one multicast service that the IAB node needs to listen to and multicast, the first network device being a centralized unit (CU) of a donor node; receiving, by the IAB node, the at least one multicast service from a parent node of the IAB node according to the at least one multicast service information; and multicasting, by the IAB node, the at least one multicast service.

[0051] According to the method for multicast communication provided in the present application, the CU of the donor node configures the multicast service that the IAB node needs to listen to and multicast, so that the IAB node can listen to and multicast the multicast service according to the configuration of the CU of the donor node, thereby realizing the multicast communication of the IAB architecture.

[0052] In some implementations of the sixth aspect, before the IAB node multicasts the at least one multicast service, the method further includes: determining, by the IAB node, configuration information of a multicast control channel according to the at least one multicast service information; sending, by the IAB node, the configuration information of the multicast control channel to the first network device; receiving, by the IAB node, system information from the first network device, the system information including the configuration information of the multicast control channel; broadcasting, by the IAB node, the system information; and sending, by the IAB node, configuration information of at least one multicast service channel on the multicast control channel according to the configuration information of the multicast control channel, the at least one multicast service channel being used for multicasting the at least one multicast service.

[0053] In some implementations of the sixth aspect, the multicast service information includes one or more of the following: a temporary mobile group identity (TMGI), a multimedia broadcast multicast service (MBMS) session identity, a group radio network temporary identifier (G-RNTI), and a logical channel identifier.

[0054] In some implementations of the sixth aspect, the IAB node includes a mobile terminal (MT) and a distributed unit (DU), and the receiving, by the IAB node, the at least one multicast service information from the first network device includes: receiving, by the MT, a radio resource control (RRC) message from the first network device, the RRC message including the at least one multicast service information; or receiving, by the DU, a first interface message from the first network device, the first interface message including the at least one multicast service information.

[0055] It should be understood that the first interface is an F1 interface.

[0056] In a seventh aspect, a method for multicast communication is provided, including: a first network device sending, to each integrated access and backhaul, IAB, node on a path between the first network device and a first terminal device, at least one multicast service information corresponding to each IAB node, the at least one multicast service information indicating at least one multicast service that the corresponding IAB node needs to listen to and multicast, the first network device being a centralized unit, CU, of a host node; and the first network device sending, to a second network device, the at least one multicast service that each IAB node needs to listen to and multicast, the second network device being a distributed unit, DU, of the host node.

[0057] According to the method for multicast communication provided in the present application, the first network device (i.e., the CU of the host node) configures multicast services that the IAB node needs to listen to and multicast, so that the IAB node can listen to and multicast the multicast services according to the configuration of the first network device, thereby realizing multicast communication of the IAB architecture.

[0058] In some implementations of the seventh aspect, the method further includes: the first network device receiving configuration information of a multicast control channel from each IAB node, wherein the configuration information of the multicast control channel of any IAB node is determined by the IAB node according to the corresponding at least one multicast service information; the first network device determining system information of each IAB node according to the configuration information of the multicast control channel of each IAB node, the system information of any IAB node including the configuration information of the multicast control channel of the IAB node; and the first network device sending the system information to each IAB node.

[0059] In some implementations of the seventh aspect, the multicast service information includes one or more of the following: TMGI, MBMS session identifier, G-RNTI, and logical channel identifier.

[0060] In some implementations of the seventh aspect, the IAB node includes a mobile terminal, MT, and a distributed unit, DU; and wherein the first network device sending, to each IAB node, at least one multicast service information corresponding to each IAB node includes: the MT sending, to a mobile terminal of each IAB node, an RRC message including the at least one multicast service information; or the DU sending, to a mobile terminal of each IAB node, a first interface message including the at least one multicast service information.

[0061] In an eighth aspect, a method for multicast communication is provided, including: receiving, by a second network device, first multicast service from a first network device, the first multicast service including a TNL address corresponding to the first multicast service, the first network device being a centralized unit (Donor-CU) of a host node, and the second network device being a distributed unit (Donor-DU) of the host node; and forwarding, by the second network device, the first multicast service to a next-hop IAB node according to first configuration information.

[0062] Optionally, the method further includes: multicasting, by the second network device, the first multicast service to terminal devices accessing the second network device according to the first configuration information, in a case where it is determined that the first multicast service needs to be multicast to the terminal devices accessing the second network device.

[0063] According to the method for multicast communication provided in the present application, the host DU can forward and multicast the first multicast service according to the first configuration information.

[0064] In some implementations of the eighth aspect, the forwarding, by the DU, of the first multicast service to the next-hop IAB node according to the first configuration information includes: adding, by the DU, routing information corresponding to the first multicast service in a backhaul adaptation protocol (BAP) header corresponding to the first multicast service according to the first configuration information, and determining a second link configuration according to the first configuration information; and transmitting, by the DU, the first multicast service to the next-hop IAB node through the second link, the BAP header corresponding to the first multicast service including the routing information.

[0065] In some implementations of the eighth aspect, before the receiving, by the second network device, of the first multicast service from the first network device, the method further includes: receiving, by the second network device, the first configuration information from the first network device.

[0066] In a ninth aspect, a method for multicast communication is provided, including: receiving, by a first integrated access backhaul (IAB) node, first multicast service; determining, by the first IAB node, whether the first multicast service needs to be forwarded to other IAB nodes according to second configuration information; in a case where the first multicast service needs to be forwarded to other IAB nodes, determining, by the first IAB node, a next-hop IAB node and a first link according to the second configuration information; and forwarding, by the first IAB node, the first multicast service to the next-hop IAB node through the first link.

[0067] Optionally, the method further comprises: determining, by the first IAB node, whether the first multicast service needs to be multicast to terminal devices accessing the first IAB node according to the second configuration information; and multicasting, by the first IAB node, the first multicast service on a multicast service channel corresponding to the first multicast service, in a case where the first multicast service needs to be multicast to terminal devices accessing the first IAB node.

[0068] It should be understood that the first IAB node is an intermediate IAB node on a path between the first network device and the first terminal device, i.e., the first IAB node is not an IAB node accessed by the first terminal device.

[0069] According to the method for multicast communication provided in the present application, the first IAB node can determine whether the received first multicast service needs to be forwarded according to the first configuration information, and determine a next-hop IAB node and a corresponding link configuration in a case where the first multicast service needs to be forwarded, and forward the first multicast service according to the link configuration. The first IAB node can also multicast the first multicast service in a case where the first multicast service needs to be multicast (air interface multicast) according to the first configuration information. In this way, the first IAB node transmits the first multicast service.

[0070] In some implementations of the ninth aspect, before the first IAB node receives the first multicast service, the method further comprises: receiving, by the first IAB node, the second configuration information from a first network device, the first network device being a centralized unit Donor-CU of a host node.

[0071] In some implementations of the ninth aspect, the first IAB node receives the second configuration information from the first network device comprises: receiving, by the first IAB node, an RRC message from the first network device, the RRC message comprising the second configuration information; or receiving, by the first IAB node, a first interface message from the first network device, the first interface message comprising the second configuration information.

[0072] It should be understood that the first interface is an F1 interface.

[0073] In some implementations of the ninth aspect, the second configuration information comprises one or more of: multicast service information corresponding to the first multicast service, routing information, a BAP address of the next-hop node, the first link configuration, and an indication of whether the first multicast service needs to be multicast to terminal devices accessing the first IAB node; wherein the routing information comprises a BAP address of a last-hop IAB node, and the routing information is used by the first IAB node to determine whether the first multicast service needs to be forwarded to other IAB nodes.

[0074] Optionally, the first link is configured as a logical channel between the first IAB node and the next-hop IAB node for forwarding the first multicast service.

[0075] In some implementations of the ninth aspect, the multicast service information comprises one or more of the following: a temporary mobile group identity, a multimedia broadcast multicast service (MBMS) session identity, a group radio network temporary identifier (G-RNTI), and a logical channel identifier.

[0076] In a tenth aspect, a method for multicast communication is provided, comprising: receiving, by a second integrated access backhaul (IAB) node, a first multicast service from a previous-hop IAB node, the first multicast service comprising a routing identifier and a multicast IP address; determining, by the second IAB node, whether the first multicast service needs to be forwarded to other IAB nodes according to the routing identifier; in a case that the first multicast service does not need to be forwarded, determining, by the first IAB node, a multicast service channel corresponding to the first multicast service according to the multicast IP address and third configuration information, wherein the third configuration information is used to indicate a correspondence between multicast service information of the first multicast service and the multicast IP address; and multicasting, by the first IAB node, the first multicast service on the multicast service channel corresponding to the first multicast service.

[0077] It should be understood that the second IAB node is the last-hop IAB node on a path between the first network device and the first terminal device, i.e., the IAB node accessed by the first terminal device.

[0078] According to the method for multicast communication provided in the present application, after receiving the first multicast service, the second IAB node can determine the multicast service channel corresponding to the first multicast service according to the third configuration information, so that the first multicast service can be multicast (over the air multicast) on the corresponding multicast service channel. In this way, the second IAB node multicasts the first multicast service.

[0079] In some implementations of the tenth aspect, before the second IAB node receives the first multicast service, the method further comprises: receiving, by the second IAB node, the third configuration information from a first network device, the first network device being a centralized unit (Donor-CU) of a host node.

[0080] In some implementations of the tenth aspect, the second IAB node receives the third configuration information from a first network device of a centralized unit of a host node, including that the second IAB node receives an RRC message from the first network device, the RRC message including the third configuration information, or the second IAB node receives a first interface message from the first network device, the first interface message including the third configuration information.

[0081] In some implementations of the tenth aspect, the multicast service information includes one or more of the following: a temporary mobile group identity, a multimedia broadcast multicast service (MBMS) session identity, a group radio network temporary identifier (G-RNTI), and a logical channel identifier.

[0082] In a eleventh aspect, another method for multicast communication is provided, including: a first network device sending first configuration information to a second network device, sending second configuration information to each first IAB node on a path between the first network device and a first terminal device, and sending third configuration information to a third IAB node, the first network device being a centralized unit (Donor-CU) of a host node, and the second network device being a distributed unit (Donor-DU) of the host node; wherein the first configuration information, the second configuration information, and the third configuration information are used to send a first multicast service; the first configuration information is used for the second network device to determine whether the first multicast service needs to be multicast to a group of terminal devices accessing the second network device, and a first IAB node receiving the first multicast service and link configuration used to send the first multicast service to the first IAB node receiving the first multicast service; the second configuration information is used for the first IAB node to determine whether the first multicast service needs to be multicast to a group of terminal devices accessing the first IAB, and another first IAB node receiving the first multicast service and link configuration used to send the first multicast service to the other first IAB node receiving the first multicast service; and the third configuration information is used for the second IAB node to determine a multicast service channel corresponding to the first multicast service.

[0083] It should be noted that the first IAB node is an intermediate IAB node, and the second IAB node is a last-hop IAB node.

[0084] According to the multicast communication method provided in the present application, the host CU configures the corresponding configuration information for multicast to the host DU, the intermediate IAB node, and the last-hop IAB node, so that the host DU, the intermediate IAB node, and the last-hop IAB node can implement multicast of the multicast service according to the corresponding configuration information.

[0085] In a twelfth aspect, a communication apparatus is provided, which includes various modules or units for performing the method in the first aspect to the eleventh aspect or any possible implementation of the first aspect to the eleventh aspect.

[0086] In a thirteenth aspect, an apparatus is provided, which includes a processor. The processor is coupled with a memory and is configured to execute instructions in the memory to cause the apparatus to perform the method in the first aspect to the eleventh aspect or any possible implementation of the first aspect to the eleventh aspect. Optionally, the apparatus further includes the memory. Optionally, the apparatus further includes an interface circuit, and the processor is coupled with the interface circuit.

[0087] In a fourteenth aspect, a processor is provided, which includes an input circuit, an output circuit and a processing circuit. The processing circuit is configured to receive a signal through the input circuit and transmit a signal through the output circuit, so that the processor performs the method in the first aspect to the eleventh aspect or any possible implementation of the first aspect to the eleventh aspect.

[0088] In a specific implementation, the processor can be a chip, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, a gate circuit, a flip-flop, various logic circuits, etc. The input signal received by the input circuit can be received and input by, for example but not limited to, a receiver, the signal output by the output circuit can be output to and transmitted by, for example but not limited to, a transmitter, and the input circuit and the output circuit can be the same circuit, which is used as the input circuit and the output circuit at different times. The embodiments of the present application do not limit the specific implementation of the processor and various circuits.

[0089] In a fifteenth aspect, a processing apparatus is provided, which includes a processor and a memory. The processor is configured to read instructions stored in the memory, and can receive a signal through a receiver and transmit a signal through a transmitter to perform the method in the first aspect to the eleventh aspect or any possible implementation of the first aspect to the eleventh aspect.

[0090] Optionally, the processor is one or more, and the memory is one or more.

[0091] Optionally, the memory can be integrated with the processor, or the memory and the processor can be separately arranged.

[0092] In a specific implementation, the memory can be a non-transitory memory, for example, a read only memory (ROM), which can be integrated with the processor on the same chip, or can be separately arranged on different chips. The embodiments of the present application do not limit the type of memory and the arrangement of the memory and the processor.

[0093] It should be understood that the relevant signal interaction process, for example, sending a downlink channel, can be a process of outputting a downlink channel from a processor. Specifically, the processed output signal can be output to a transmitter, and the input signal received by the processor can come from a receiver. Among them, the transmitter and the receiver can be collectively referred to as a transceiver.

[0094] The processing device in the fifteenth aspect described above can be a chip, and the processor can be implemented by hardware or software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc. When implemented by software, the processor can be a general-purpose processor, which is implemented by reading software code stored in a memory. The memory can be integrated in the processor or exist independently outside the processor.

[0095] The sixteenth aspect provides a computer program product, which includes a computer program (also referred to as code or instructions), which, when executed, causes a computer to perform the method in the first aspect to the eleventh aspect or any possible implementation manner of the first aspect to the eleventh aspect.

[0096] The seventeenth aspect provides a computer-readable medium storing a computer program (also referred to as code or instructions), which, when executed on a computer, causes the computer to perform the method in the first aspect to the eleventh aspect or any possible implementation manner of the first aspect to the eleventh aspect. BRIEF DESCRIPTION OF DRAWINGS

[0097] Figure 1 FIG. 1 is a schematic diagram of a CU-DU architecture.

[0098] Figure 2 FIG. 2 is a schematic diagram of a multicast-unicast hybrid mechanism.

[0099] Figure 3 FIG. 3 is a schematic flowchart of a method for multicast communication provided by the present application.

[0100] Figure 4 FIG. 4 is an example diagram of the correspondence between logical channels of a terminal device and multicast services.

[0101] Figure 5 FIG. 5 is a schematic flowchart of another method for multicast communication provided by the present application.

[0102] Figure 6 FIG. 6 is a schematic diagram of an IAB network topology.

[0103] Figure 7 FIG. 7 is a schematic diagram of the composition of an IAB node.

[0104] Figure 8 is an example of a user plane protocol stack architecture of an IAB network.

[0105] Figure 9 is an example of a control plane protocol stack architecture of an IAB network.

[0106] Figure 10 is a schematic flowchart of a method for multicast communication provided by the present application.

[0107] Figure 11 is another schematic diagram of a method for multicast communication provided by the present application.

[0108] Figure 12 is an example of a method for multicast communication shown in Figure 11

[0109] Figure 13 is a schematic flowchart of a method for multicast communication provided by the present application.

[0110] Figure 14 is an example of a method for multicast communication shown in Figure 13

[0111] Figure 15 is a schematic block diagram of a communication apparatus provided by the present application.

[0112] Figure 16 is a schematic block diagram of a network device provided by the present application.

[0113] Figure 17 is a schematic block diagram of a terminal device provided by the present application. DETAILED DESCRIPTION

[0114] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0115] In the description of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B. "And / or" in this document is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and B exists alone. In addition, in the description of the present application, unless otherwise specified, "multiple" means two or more. In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the same items or similar items with basically the same functions and effects are distinguished by using "first", "second", etc. The skilled in the art can understand that "first", "second", etc. do not limit the quantity and execution order, and "first", "second", etc. also do not limit the difference.​​

[0116] The names of all nodes and messages in the present application are only names set for the convenience of description, and the names in the actual network can be different. It should not be understood that the present application limits the names of various nodes and messages. On the contrary, any name having the same or similar function as the nodes or messages used in the present application is considered as a method or equivalent replacement of the present application, and is within the protection scope of the present application, and the following will not be described again.

[0117] The technical solutions of the embodiments of the present application can be applied to various communication systems, for example: a worldwide interoperability for microwave access (WiMAX) communication system, a new radio (NR) in a 5th generation (5G) system or other communication systems that can appear in the future.

[0118] The terminal device in the embodiments of the present application can refer to a user equipment (UE), an access terminal, a user unit, a user station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent or a user device. The terminal device can also be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a 5G network or a terminal device in a future evolved public land mobile network (PLMN), etc. The embodiments of the present application are not limited thereto.

[0119] The network device in the embodiments of the present application can be a device for communicating with a terminal device. For example, the network device can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next generation NodeB (gNB) in a 5G mobile communication system, a base station in a future mobile communication system, an access node in a WiFi system, a wireless controller in a cloud radio access network (CRAN) scenario, a relay station, an access point, a vehicle-mounted device, a wearable device, a network device in other future evolved communication systems, and the like. The present application does not limit the specific technology and specific device form adopted by the network device.

[0120] In some communication systems, such as a 5G communication system, a network device can be logically divided into a CU and a DU. The following takes a gNB as an example to explain this in detail.

[0121] Figure 1 A CU-DU architecture diagram is shown. Referring to Figure 1 , gNBs are connected through an Xn interface. A gNB and a 5G core (5GC) are connected through an NG interface. A gNB can be composed of a CU and a DU, that is, the functions of the gNB are split, part of the functions of the gNB are deployed in a CU, and the remaining functions are deployed in a DU. The CU and the DU can be connected through an F1 interface, and the F1 interface supports a user plane protocol (F1-U / F1*-U) and a control plane protocol (F1-C / F1*-C). The CU represents the gNB to connect to the core network through the NG interface, and the CU represents the gNB to connect to other gNBs through the Xn interface. The CU and the DU can be physically separated or deployed together. Multiple DUs can share one CU.

[0122] The splitting of the CU and the DU can be according to a protocol stack. In one possible manner, a radio resource control (RRC) layer, a service data adaptation protocol (SDAP) layer, and a packet data convergence protocol (PDCP) layer are deployed in the CU, and a radio link control (RLC) layer, a media access control (MAC) layer, and a physical layer (PHY) are deployed in the DU. It can be understood that the above-mentioned division manner is only an example, and the CU and the DU can also be divided in other manners. For example, part of the functions of the RLC layer and the functions of the protocol layers above the RLC layer can be arranged in the CU, and the remaining functions of the RLC layer and the functions of the protocol layers below the RLC layer can be arranged in the DU. For another example, the functions of the CU or the DU can also be divided according to a service type or other system requirements. For example, according to a delay, the functions that need to meet a delay requirement in processing time are arranged in the DU, and the functions that do not need to meet the delay requirement are arranged in the CU. In addition, the CU can also be in a form of separation of a control plane (CP) and a user plane (UP), for example, the CU can be composed of one CU-CP and one or more CU-UPs. It should be understood that the functions of the CU and the DU can be arranged as needed in a specific implementation, and the embodiments of the present application do not make any limitation in this regard.

[0123] It should be understood that the name of the interface between each unit described in the foregoing and the following is only an example, and the name of the interface can be other names in a specific implementation, and the present application does not make any specific limitation in this regard. For example, the interface between the gNBs can be referred to as an Xn interface, and other naming can also be used. The interface between the CU and the DU can be referred to as an F1 interface, and other names can also be used.

[0124] Before introducing the present application, it should be first explained that the sending / forwarding / multicast multicast service described in the present application refers to multicast data of the sending / forwarding / multicast multicast service.

[0125] In order to effectively utilize mobile network resources, the 3rd generation partnership project (3GPP) introduced a multimedia broadcast multicast service (MBMS), which is a technology for transmitting data from a data source to multiple targets, achieving network resource sharing and improving resource utilization, especially air interface resource. The MBMS service can be transmitted in an MBSFN transmission mode or a single cell-point to multi-point (SC-PTM) transmission mode. The MBSFN transmission mode requires synchronous transmission of all cells in an MBSFN area at the same time and on the same frequency, and the SC-PTM transmission mode performs multicast in a single cell. The MBSFN area refers to a group of cells that achieve MBSFN transmission through coordination.

[0126] The MBSFN transmission mode involves two types of logical channels:

[0127] (1) Multicast traffic channel (MTCH)

[0128] (2) Multicast control channel (MCCH)

[0129] The MTCH is used to carry data of at least one MBMS service. A large number of MBMS services provided by one MBSFN area can require configuration of multiple MTCHs.

[0130] The MCCH is used to carry configuration information of one MBSFN area and configuration information of MBMS services provided in the MBSFN area.

[0131] The MCCH and one or more MTCHs can be multiplexed and mapped to a transmission channel multicast channel (MCH), and the MCH is mapped to a physical multicast channel (PMCH) and transmitted on an MBSFN subframe.

[0132] In MBSFN transmission mode, the DU broadcasts the configuration information of the MCCH of each MBSFN area in the cell in a broadcast message, e.g., system information block (SIB) 13. Then, the DU transmits the configuration information of the MBSFN area and the configuration information of the MBMS service provided in the MBSFN area in the MCCH. Then, the DU can multicast the MBMS service on the MTCH (or PMCH). Accordingly, the terminal device obtains the configuration information of the MCCH of each MBSFN area by receiving the broadcast message, then listens to the MCCH according to the configuration information of the MCCH, and obtains the configuration information of the MBMS service provided in the MBSFN area from the MCCH, from which the terminal device selects the MBMS service of interest, and listens to the MBMS service on the MTCH according to the configuration information of the MBMS service.

[0133] SC-PTM transmission mode involves two types of logical channels:

[0134] (1) Single-cell multicast control channel (SC-MCCH)

[0135] (2) Single-cell multicast traffic channel (SC-MTCH)

[0136] The SC-MTCH is used to carry one MBMS service. If the number of MBMS services to be provided in a cell is large, multiple SC-MTCHs need to be configured.

[0137] The SC-MTCH is used to carry the configuration information of the MBMS service provided in a cell.

[0138] The SC-MCCH and one or more SC-MTCHs can be multiplexed and mapped to a downlink shared channel (DL-SCH), which is mapped to a physical downlink shared channel (PDSCH).

[0139] In the SC-PTM transmission mode, the DU first broadcasts the configuration information of the SC-MCCH in a broadcast message, such as SIB20. Then, the DU transmits control information required for receiving the SC-MTCH in the SC-MCCH channel, for example, the control information can include the configuration information of the SC-MTCH. Then, the DU can multicast the MBMS service in the SC-MTCH. Correspondingly, the terminal device obtains the configuration information of the SC-MCCH by receiving the broadcast message, then listens to the SC-MCCH according to the configuration information of the SC-MCCH, and obtains the control information required for receiving the SC-MTCH from the SC-MCCH, selects the interested MBMS service according to the control information, and listens to the MSMS service on the interested SC-MTCH.

[0140] At present, a multicast-unicast hybrid mechanism is discussed. Based on the mechanism, the multicast service data can be sent to the terminal device by the unicast mode or by the multicast mode.

[0141] Figure 2 An illustrative diagram of the multicast-unicast hybrid mechanism is shown. Referring to Figure 2 The anchor points of the unicast and the multicast are on the same PDCP entity, and the terminal device can identify whether it is unicast or multicast by the cell radio network temporary identifier (C-RNTI) and the group radio network temporary identifier (G-RNTI). It should be understood that the anchor points of the unicast and the multicast on the same PDCP entity is only an implementation of the multicast-unicast hybrid mechanism, and in practice, the anchor points of the unicast and the multicast can be on different PDCP entities.

[0142] Under the CU-DU architecture, how to implement the transmission of the multicast service by the unicast mode has not been related technology.

[0143] Therefore, the present application provides a multicast method which can implement the transmission of the multicast service by the unicast mode under the CU-DU architecture. The method will be described in detail below.

[0144] Figure 3 is an illustrative flowchart of a method for multicast communication provided by the present application. The steps in the method 300 will be described below.

[0145] S310, the first network device sends first information to the second network device. Correspondingly, the second network device receives the first information.

[0146] The first network device is a CU, and the second network device is a DU. The CU and the DU can correspond to the same access network device or base station. The CU has a packet data convergence protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function of the access network device. The CU has a radio link control layer function, a medium access control layer function, and a physical layer function of the access network device.

[0147] The first information is used to indicate an association relationship between the multicast service information and the first terminal device, that is, the first information is used to indicate that the multicast service information is associated with the first terminal device. According to the first information, the DU can determine that the first terminal device needs to listen to a multicast service indicated by the multicast service information.

[0148] The multicast service information is used to indicate a multicast service, that is, an MBMS service. For example, the multicast service information can include one or more of the following: a multicast area identifier, a temporary mobile group identifier (TMGI), a session identifier, and a group radio network temporary identifier (G-RNTI). That is, a combination of one or more of the above can be used to identify the multicast service. For example, for MBSFN, the multicast service information can include one or more of the following: a multicast area identifier, a TMGI, and a session identifier. For SC-PTM, the multicast service information can include one or more of the following: a TMGI, a session identifier, and a G-RNTI.

[0149] The multicast area refers to an MBSFN area.

[0150] The session identifier is an MBMS session identifier (i.e., an MBMS session ID), a TMGI, or an MBMS session, or a TMGI and an MBMS session, corresponding to an MBMS service.

[0151] The G-RNTI is used for scrambling / descrambling of the multicast service. One G-RNTI corresponds to one SC-MTCH, and one SC-MTCH corresponds to one multicast service.

[0152] Optionally, the first information can be implemented in the following two ways:

[0153] Method one

[0154] The first information can include multicast service information and information of at least one terminal device associated with the multicast service information, the at least one terminal device including the first terminal device. The information of one terminal device is used to indicate the terminal device.

[0155] Taking the first terminal device as an example, for example, the information of the first terminal device can be a combination of one or more of the following: C-RNTI, gNB-CU UE F1AP ID, gNB-DU UE F1AP ID. The C-RNTI is an identifier of the first terminal device identified by the network device over the air, used to scramble / descramble information for the first terminal device. The gNB-CU UE F1AP ID represents an identifier of the first terminal device used by the CU on the F1 interface, and the gNB-DU UE F1AP ID represents an identifier of the first terminal device used by the DU on the F1 interface. It should be understood that the information of the first terminal device can also be other identifiers used by the CU and the DU to identify the first terminal device.

[0156] For example, the first information can include or be the following information elements:

[0157] > Multicast service information

[0158] > UE ID list

[0159] >> UE ID

[0160] >> DRB ID

[0161] The multicast service information can be one or more combinations of TMGI, MBMS session ID and G-RNTI; the UE ID list is the information of at least one terminal device associated with the multicast service information, wherein the information of each terminal device is represented by a UE ID. The UE ID can be C-RNTI, gNB-CU UE F1AP ID, gNB-DU UE F1AP ID, etc. Optionally, the first information can also contain the DRB ID corresponding to each terminal device corresponding to the multicast service.

[0162] It should be understood that the possible forms of multicast service information and UE ID in the following can be referred to the description herein, which will not be described in detail.

[0163] Optionally, the first information can be carried through the interface message between the CU and the DU, for example, through the Session Start / Modification Request message, which is non-UE associated signaling, i.e. independent of the terminal device.

[0164] Method two

[0165] The first information can comprise an association relationship between the first DRB of the first terminal device and the multicast service information. According to the first information, the DU can determine that the first DRB transmits the multicast service corresponding to the multicast service information.

[0166] For example, the first information can comprise or be the following information element:

[0167] >DRB to Be Setup List

[0168] >>DRB ID

[0169] >>multicast service information

[0170] The DRB to Be Setup List indicates the DRB that needs to be established by the first terminal device, and comprises the first DRB. The DRB ID is the identifier of the DRB.

[0171] Optionally, the first information can be carried by an interface message between the CU and the DU, for example, by a context setup or modification request message for the first terminal device. The message is related to the terminal device, that is, UE-associated signaling.

[0172] S320, the second network device sends second information to the first network device. Correspondingly, the first network device receives the second information.

[0173] Specifically, after receiving the first information, the DU determines the second information according to the first information, and sends the second information to the CU.

[0174] In the case where the first information is implemented in the above-mentioned manner one, the second information can be used to indicate the association relationship between the multicast service information and the first logical channel, that is, the second information can indicate the first logical channel associated with the multicast service information. After the association between the multicast service information and the first logical channel, the DU can transmit the multicast service corresponding to the multicast service information to the first terminal device by using the first logical channel.

[0175] For example, the second information can comprise the following information element:

[0176] >multicast service information

[0177] >>logicalChannelIdentity

[0178] The logicalChannelIdentity is the first logical channel identifier of the first terminal device associated with the multicast service information, and the first logical channel corresponds to the first DRB. Optionally, the second information can also carry the DRB ID corresponding to the logicalChannelidentity.

[0179] For example, the multicast service information and the associated first logical channel identifier can be included in a cell group configuration (CellGroupConfig) corresponding to the first terminal device.

[0180] It should be understood that the CellGroupConfig hereinafter can refer to the description herein and will not be described again hereinafter.

[0181] It should also be understood that the second information can also indicate an association relationship between the multicast service information and a logical channel of another terminal device in the at least one terminal device associated with the multicast service information. For example, the second information can also indicate an association relationship between the multicast service information and a second logical channel of a second terminal device associated with the multicast service information. After the association between the multicast service information and the second logical channel, the DU can transmit the multicast service corresponding to the multicast service information to the second terminal device through the second logical channel.

[0182] For example, the second information can include or be the following information element:

[0183] > UE configuration List

[0184] >> UE ID

[0185] >> CellGroupConfig

[0186] The UE configuration List includes the identifier of the first terminal device.

[0187] The UE ID can also not be included in the second information, and in this case, the order of the CellGroupConfig in the UE configuration List corresponds to the order of the information of the terminal device in the first information. For example, the information of the at least one terminal device in the first information is in turn UE ID #1, UE ID #2, and UE ID #3, and the order of the CellGroupConfig in the UE configuration List in the second information is in turn CellGroupConfig #1, CellGroupConfig #2, and CellGroupConfig #3. The CellGroupConfig #1 corresponds to the UE ID #1, the CellGroupConfig #2 corresponds to the UE ID #2, and the CellGroupConfig #3 corresponds to the UE ID #3.

[0188] Optionally, the second information may be carried through an interface message between the CU and the DU, for example, through a Session Start / Modification Response message.

[0189] When the first information is implemented using the second method described above, the second information can be used to indicate the association between the first DRB and the first logical channel of the first terminal device. For example, the second information can include the first DRB identifier and the associated first logical channel identifier. It should be understood that the second information can also include other DRB identifiers and associated logical channel identifiers of the first terminal device.

[0190] Optionally, the second information may be carried via an interface message between the CU and the DU, such as a context establishment or modification response message for the first terminal device.

[0191] S330: The first network device generates a configuration message according to the second information.

[0192] The configuration message may be used to indicate the association between the multicast service information and the first logical channel. In other words, the configuration message is used to indicate the association between the multicast service information and the first logical channel. In addition, the configuration message may also include the SDAP / PDCP configuration on the CU side.

[0193] For example, the CU may generate a corresponding configuration message for each terminal device according to the second information. For example, as mentioned above, the DU provides the CellGroupConfig#1 corresponding to UE#1, UE#2 and UE#3 in S320.

[0194] CellGroupConfig#2 and CellGroupConfig#3. Then the CU generates a corresponding configuration message for UE#1, and the configuration message includes CellGroupConfig#1. Similarly, the corresponding configuration messages generated for UE#2 and UE#3 include CellGroupConfig#2 and CellGroupConfig#3 respectively.

[0195] Exemplarily, when the first information is implemented using method one, the CU can determine, based on the second information, that the logical channel of the first terminal device associated with the multicast service information is the first logical channel, and then generate a configuration message, wherein the configuration message may include the multicast service information and the associated first logical channel identifier.

[0196] Exemplarily, in a case that the first information is implemented in the second information mode, the CU can learn from the second information that the first DRB is associated with the first logical channel of the first terminal device, and then can determine that the multicast service information is associated with the first logical channel, so as to generate a configuration message, wherein the configuration message can include the multicast service information and the identifier of the associated first logical channel.

[0197] In S340, the first network device sends the configuration message to the first terminal device. Correspondingly, the first terminal device receives the configuration message.

[0198] After receiving the configuration message, the first terminal device can determine that the multicast service is associated with the first logical channel. After the subsequent DU receives the multicast service corresponding to the multicast service information from the first CU, the multicast service can be mapped to the first logical channel, and correspondingly, the first terminal device can receive the multicast service corresponding to the multicast service information from the first logical channel.

[0199] For example, as shown in FIG. 6, the DU maps the multicast service to the corresponding multicast service channel for multicasting. After receiving the multicast service channel, the first terminal device submits the multicast service received by the multicast service channel to the PDCP entity corresponding to the first logical channel according to the mapping relationship between the multicast service information and the first logical channel. Figure 2

[0200] For another example, referring to FIG. 7, the multicast service 1 corresponds to the logical channel 1 of the first terminal device. After the CU sends the multicast service 1 to the DU, the DU maps the multicast service 1 to the logical channel 1 and transmits the multicast service 1 to the first terminal device. Figure 4

[0201] Optionally, the configuration message can be an RRC reconfiguration message.

[0202] In summary, according to the method provided in the present application, the multicast service information and the logical channel of the terminal device can be associated through the interaction between the CU and the DU, the multicast service can be transmitted through the unicast mode, and the flexible transmission of the multicast service can be realized.

[0203] In the CU-DU architecture, the multicast-related system information belongs to other system information, i.e., other SI, such as SIB13 and SIB20, which is generated by the CU and sent to the DU, and the DU broadcasts the system information. However, how the CU generates the system information is not recorded at present.

[0204] Therefore, the present application provides a method for multicast communication, which can provide configuration information of a multicast control channel to the CU by the DU, and the CU can generate multicast-related system information according to the configuration information. The method is described in detail as follows.

[0205] Figure 5 ​​is a schematic flow chart of a method for multicast communication provided by the present application. The steps of the method 500 are described as follows.

[0206] S510, the first network device sends multicast service information to the second network device. Correspondingly, the DU receives the multicast service information.

[0207] The first network device is a CU, and the second network device is a DU. The CU and the DU can correspond to the same access network device or base station. The CU has the packet data convergence protocol layer function, the service data adaptation protocol layer function and the radio resource control layer function of the access network device. The CU has the radio link control layer function, the medium access control layer function and the physical layer function of the access network device. The multicast service information is used to indicate a multicast service, and possible forms thereof can be referred to the description above, which will not be described herein.

[0208] Optionally, the CU can also send the multicast service type corresponding to the multicast service information, i.e. MBMS or SC-PTM, to the DU.

[0209] Optionally, the multicast service information can be carried by an interface message between the CU and the DU, such as a session start / modification request message. In addition to the multicast service information, the session start / modification request message can also carry the CU side transport network layer (TNL) address information corresponding to each multicast service. The TNL address information includes an IP address and a tunnel endpoint identifier (TEID).

[0210] S520, the second network device determines the configuration information of the multicast control channel according to the multicast service information.

[0211] The configuration information of the multicast control channel can be associated with one or more multicast services. For example, at least one TMGI (or one TMGI and an MBMS session ID) corresponds to the configuration information of one multicast control channel. If the CU provides the multicast service type corresponding to the multicast service information, the DU can also determine the configuration information of the corresponding multicast control channel according to the multicast service type. For example, when the multicast service type is an MBMS type, the configuration information of the multicast control channel can include one or more of the following: a repetition period of the multicast control channel, an offset of the multicast control channel, a modification period of the multicast control channel, subframe allocation information of the multicast control channel, a signaling modulation and coding strategy, MBSFN area configuration information, a notification indication, a non-MBSFN area length, etc. For example, when the multicast service type is an SC-PTM type, the configuration information of the multicast control channel can include one or more of the following: a repetition period of the multicast control channel and an offset of the multicast control channel. The offset of the multicast control channel and the repetition period of the multicast control channel are used to determine the starting time point of the multicast control channel. The system frame number SFN divided by the repetition period of the multicast control channel is the offset of the multicast control channel. The notification indication is used to indicate which PDCCH bit is used to notify the UE of changes related to the multicast control channel. The non-MBSFN area length indicates how many symbols at the beginning of the subframe are used for non-MBSFN areas.

[0212] For example, for the MBSFN transmission mode, the multicast control channel can be an MCCH; for the SC-PTM transmission mode, the multicast control channel can be an SC-MCCH.

[0213] S530, the second network device sends the configuration information to the first network device. Accordingly, the first network device receives the configuration information.

[0214] Optionally, the multicast service information can be carried through an interface message between the CU and the DU, such as a session start / modification response message. In addition to the configuration information corresponding to the multicast service information, the session start / modification request message can also carry the DU-side TNL address information corresponding to each multicast service. The CU and the DU can establish a corresponding user plane tunnel for each multicast service according to the CU-side TNL address information and the DU-side TNL address information provided by each other.

[0215] S540, the first network device generates system information according to the configuration information. The system information includes the configuration information.

[0216] For example, for the MBSFN transmission mode, the CU can generate an SIB13 according to the configuration information; for the SC-PTM transmission mode, the CU can generate an SIB20 according to the configuration information.

[0217] S550, the first network device sends the system information to the second network device. Accordingly, the second network device receives the system information.

[0218] For example, the CU can send the system information to the DU through an interface message between the CU and the DU, such as a CU configuration update request message.

[0219] S560, the second network device broadcasts the system information.

[0220] After the DU receives the system information, the DU can broadcast the system information through the air interface according to a period corresponding to the system information.

[0221] After that, the method can further include:

[0222] The DU sends configuration information of a multicast service channel, such as MBSFNAreaConfiguration or SCPTMConfiguration, on the multicast control channel according to the configuration information of the multicast control channel; the CU sends the multicast service indicated by the multicast service information to the DU; and the DU broadcasts the multicast service.

[0223] The configuration information of the multicast service channel, for example, the content included in MBSFNAreaConfiguration or SCPTMConfiguration, can refer to the prior art. For example, for the MBSFN transmission mode, the configuration information of the multicast service channel can include one or more of the following: commonSF-Alloc, commonSF-AllocPeriod, pmch-InfoList, etc. Among them, commonSF-Alloc represents the subframe allocated to the MBSFN area. commonSF-AllocPeriod represents the period of the subframe allocated to the MBSFN area. pmch-infoList contains a set of pmch-info. Each pmch-info contains pmch-config and corresponding mbms-SessionInfoList, etc. Among them, pmch-config contains sf-AllocEnd, dataMCS and mch-SchedulingPeriod. Among them, sf-AllocEnd represents the last subframe allocated to the (P)MCH, dataMCS represents the modulation and coding strategy adopted by the multicast service, and Mch-SchedulingPeriod represents the scheduling period of the MCH. mbms-SessionInfolist contains TMGI, sessionId and logicalChannelIdentity, etc. For the SC-PTM transmission mode, the configuration information SCPTMConfiguration of the multicast service channel can include sc-mtch-InfoList and scptm-NeighbourCellList. Among them, sc-mtch-InfoList contains a set of sc-mtch-info. Each sc-mtch-info can include one or more of the following: mbmsSessionInfo (i.e. MBMS session information), G-RNTI, sc-mtch-schedulingInfo (i.e. SC-MTCH scheduling information), sc-mtch-neighborCell (i.e. SC-MTCH scheduling cell information). Among them, mbmsSessionInfo contains TMGI, and optionally mbmssessionId.

[0224] Specifically, how the DU multicasts the multicast service can refer to the related prior art, which will not be repeated here.

[0225] In summary, according to the method for multicast communication provided in the present application, the DU can determine and send the configuration information of the corresponding multicast control channel to the CU according to the multicast service information sent by the CU, and the CU can generate system information related to multicast according to the configuration information.

[0226] 5G system introduces an integrated access and backhaul (IAB) technology. In an IAB network based on the IAB technology, both access links and backhaul links adopt a wireless transmission scheme to avoid fiber deployment.

[0227] In an IAB network, an IAB node can provide a terminal device with wireless access service, and service data of the terminal device is transmitted by the IAB node to a donor node through a wireless backhaul link. It should be understood that the IAB node in the present application can also be referred to as a relay node (RN), and the donor node can also be referred to as an IAB donor or a donor gNodeB (DgNB).

[0228] Figure 6 A schematic diagram of an IAB network is shown. Referring to Figure 6 , the parent node of the IAB node 1 is the donor node, the IAB node 1 is the parent node of the IAB node 2 and the IAB node 3, the IAB node 2 and the IAB node 3 are the parent nodes of the IAB node 4, and the parent node of the IAB node 5 is the IAB node 3. The uplink data packet of the UE can be transmitted to the donor node through one or more IAB nodes, and then transmitted to the mobile gateway device (for example, the user plane function unit UPF in the 5G core network) by the donor node. The downlink data packet of the UE is received by the donor node from the mobile gateway device, and then transmitted to the UE through the IAB node. Among them, there are two available paths for data transmission between UE1 and the donor node. Path 1: UE1→IAB node 4→IAB node 3→IAB node 1→donor node, and UE1→IAB node 4→IAB node 2→IAB node 1→donor node. There are three available paths for data packet transmission between UE2 and the donor node, which are: UE2→IAB node 4→IAB node 3→IAB node 1→donor node, UE2→IAB node 4→IAB node 2→IAB node 1→donor node, and UE2→IAB node 5→IAB node 2→IAB node 1→donor node.

[0229] It should be understood that on the transmission path of the host node to the UE, the IAB node accessed by the UE can be referred to as the last-hop IAB node, and the other IAB nodes can be referred to as intermediate IAB nodes. Taking the following path as an example: host node→IAB node 1→IAB node 3→IAB node 4→UE 1, IAB node 4 can be referred to as the last-hop IAB node, that is, the last-hop IAB node on the path between the host node and UE 1, and IAB node 3 and IAB node 1 are both intermediate IAB nodes, that is, intermediate IAB nodes on the path between the host node and UE 1.

[0230] It should be understood that, Figure 6 The IAB network shown is only an exemplary networking mode, and the specific networking mode of the IAB network is not limited in the present application.

[0231] The IAB node can be composed of an MT (mobile termination) part and a DU part. When the IAB node faces its parent node, it can act as a terminal device, that is, the role of MT; when the IAB faces its child node (the child node can be another IAB node or a normal terminal device), it is regarded as a network device, that is, the role of DU.

[0232] The host node can be a network device with a standalone state of base station function, and can also be a network device with a CU and DU separated form of base station function. The host node is connected to the core network (for example, connected to the 5G core network, 5GC) element serving the terminal device, and provides wireless backhaul function for the IAB node. For convenience of description, the centralized unit of the host node is referred to as the host CU, and the distributed unit of the host node is referred to as the host DU, wherein the host CU can also be in a form of separation of control plane and user plane.

[0233] Referring to Figure 7 , Figure 7 is a schematic diagram of the composition of the IAB node. The UE is connected to the host node through the IAB node 2 and the IAB node 1. Among them, the IAB node 1 and the IAB node 2 each include a DU part and an MT part. The DU part of the IAB node 2 provides access service for the UE. The DU part of the IAB node 1 provides access service for the MT part of the IAB node 2. The DU part of the IAB node 1 can also provide access service for other UEs within the coverage of the IAB node 1. The DU part of the host node provides access service for the MT part of the IAB node 1.

[0234] The IAB technology introduces a new protocol layer, i.e., a backhaul adaptation protocol (BAP) layer, on the wireless backhaul link, which is above the radio link control (RLC) layer and can be used to implement data packet routing on the wireless backhaul link and functions such as bearer mapping.

[0235] Between the IAB node (DU part of the IAB) and the donor node (or donor CU), an F1 interface needs to be established over the air interface, which supports user plane protocol (F1-U) and control plane protocol (F1-C). It should be understood that F1 can also be replaced by F1* or other names, and the present application does not limit the name. In this paper, it can be referred to as F1.

[0236] Figure 8 is an example of a user plane protocol stack architecture of an IAB network. In Figure 8 In the protocol architecture shown in FIG. 1, the meanings of the respective protocol layers are as follows: a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a general packet radio service tunneling protocol user plane (GTP-U) layer, a user datagram protocol (UDP) layer, an internet protocol (IP) layer, an L2 layer, an L1 layer, a radio link control (RLC) layer, a medium access control (MAC) layer, and a physical (PHY) layer. The L2 layer is a link layer. For example, the L2 layer can be a data link layer in the open systems interconnection (OSI) reference model. The L1 layer can be a physical layer. For example, the L1 layer can be a physical layer in the OSI reference model.

[0237] Figure 9 is an example of a control plane protocol stack architecture of an IAB network. Figure 8 The introduction of the respective protocol layers in Figure 9 is also applicable, but there are some differences. For example, Figure 9The F1 interface between the IAB node and the donor CU adopts an F1 control plane (F1-C) protocol stack, which includes an F1 application protocol (F1AP) layer and a stream control transmission protocol (SCTP) layer.

[0238] It should be noted that, Figure 8 and 9 respectively show an example of an end-to-end user plane and control plane protocol stack architecture for transmitting data services of a UE in an IAB network. Alternatively, the protocol stack architecture can also have other possibilities. For example, a protocol layer for security protection is introduced on the F1 interface between the IAB node 2 and the donor CU, and the protocol stack architecture will change.

[0239] The current technology does not involve related solutions of supporting multicast mechanism in the IAB architecture. Therefore, the present application provides a multicast method, which can solve the problem of supporting multicast mechanism in the IAB architecture. The method is described below.

[0240] Figure 10 is a schematic flowchart of a method for multicast communication provided by the present application. The steps in the method 900 are described below.

[0241] S910, the CU of the host node (i.e., the donor CU, also referred to as the first network device) sends first configuration information to the DU of the host node (i.e., the donor DU, also referred to as the second network device), sends second configuration information to each intermediate IAB node on the path between the donor CU and the first terminal device, and sends third configuration information to the last-hop IAB node.

[0242] It should be understood that the intermediate IAB node can also be referred to as the first IAB node, and the last-hop IAB node can also be referred to as the second IAB node. The first terminal device accesses the last-hop IAB node.

[0243] The first configuration information, each second configuration information, and the third configuration information are all related to at least one multicast service. In the following, the first configuration information, the second configuration information, and the third configuration information are described by taking one of the at least one multicast service (i.e., the first multicast service) as an example. It should be understood that the first multicast service is a multicast service that needs to be multicast by the last-hop IAB node over the air interface.

[0244] The first configuration information is used by the host DU to: (1) determine whether the received multicast service is a first multicast service; and (2) upon receiving the first multicast service, determine whether to multicast (i.e., air interface multicast) the multicast service, determine to which IAB node to forward the multicast service (i.e., which IAB node is the next hop IAB node), and through which logical channel to forward the multicast service to the next hop IAB node.

[0245] The second configuration information is used by the intermediate IAB node upon receiving the first multicast service to: (1) determine whether to air interface multicast the first multicast service; (2) upon determining to air interface multicast the first multicast service, determine a multicast service channel corresponding to the first multicast service; (3) determine whether to forward the first multicast service; and (4) upon determining to forward the first multicast service, determine to which IAB node to forward the first multicast service and through which logical channel to forward to the next hop IAB node.

[0246] The third configuration information is used by the last hop IAB node upon receiving the first multicast service to determine a multicast service channel corresponding to the first multicast service.

[0247] For example, the first configuration information can include any one or a combination of the following: multicast service information, TNL address information, routing information, a BAP address of the next hop IAB node, link configuration (e.g., backhaul link configuration or backhaul radio link control channel (BH RLC CH) configuration), and an indication of whether to multicast (i.e., air interface multicast).

[0248] The multicast service information is used to indicate the first multicast service, and possible forms thereof can be found in the description of S310 above. In the following examples, the first multicast service information is taken as an example of TMGI.

[0249] The TNL address information corresponds to the multicast service and includes an IP address and a TEID. The IP address can be referred to as a multicast IP address, and the TEID can be referred to as a multicast TEID. The TNL address information and the multicast service information are in a one-to-one correspondence, for example, TMGI#1 corresponds to TNL address information#1, i.e., TMGI#1 corresponds to IP address#1 and TEID#1, and TMGI#2 corresponds to TNL address information#2, i.e., TMGI#2 corresponds to IP address#2 and TEID#2.

[0250] Routing information: can be represented as routing ID. The routing information can include BAP address of the last hop IAB node and path ID, where the path ID is used to indicate different transmission paths, for example, different path IDs can correspond to different next hop nodes.

[0251] After the host DU receives the first multicast service, the routing information can be encapsulated in the BAP layer corresponding to the first multicast service.

[0252] The multicast service information corresponds to at least one routing information. For example, TMGI#1 corresponds to TNL address information#1, and at the same time corresponds to routing information#1. TMGI#2 corresponds to TNL address information#2, and at the same time corresponds to routing information#2 and routing information#3.

[0253] BAP address of the next hop IAB node: the BAP address of the next hop IAB node corresponding to the first multicast service when the host DU needs to forward the first multicast service.

[0254] Link configuration: the host DU forwards the first multicast service according to the link configuration when it is determined that the first multicast service needs to be forwarded. The link configuration can be a combination of one or more of the following: logical channel identifier corresponding to the first multicast service, DRB identifier corresponding to the first multicast service, RLC backhaul channel identifier corresponding to the first multicast service. The link configuration corresponds to the BAP address of the next hop IAB node. The link configuration and the BAP address of the next hop IAB node are considered as a configuration combination. The routing information corresponds to at least one configuration combination. For example, multicast service#1 corresponds to routing information#1, routing information#1 and (BAP address#1, link configuration#1), and (BAP address#2, link configuration#2) correspond. Multicast service#2 corresponds to routing information#2 and routing information#3. Routing information2# and (BAP address#3, link configuration#3) correspond. Routing information#3 and (BAP address#4, link configuration#4) and (BAP address#5, link configuration#5) correspond.

[0255] Indication of whether multicast is needed: the DU can determine whether to perform air interface multicast of the first multicast service according to the indication. The indication can be a multicast indication, and when the multicast indication is included, it means that the DU needs to perform air interface multicast. The indication can be a 1 / 0 indication or a true / false indication, and when the indication is 1 or true, it means that the DU needs to perform air interface multicast. When the indication is 0 or false, it means that the DU does not need to perform air interface multicast.

[0256] When the host DU receives the multicast service from the CU, it will determine which multicast service according to the TNL address information contained in the IP / UDP / GTP-U header encapsulating the multicast service, and the correspondence between the TNL address information and the multicast service information, and at the same time it will determine which routing information should be filled in the BAP layer encapsulating the multicast service according to the correspondence between the multicast service information (or multicast service) and the routing information. Then it will determine to which next hop IAB node and through which backhaul to forward the multicast service according to the next hop IAB node and the link configuration. And the host DU will determine whether to multicast the multicast service through the air interface according to the indication of whether multicast is needed. When the multicast service needs to be multicast through the air interface, it means that the host DU needs to copy multiple copies of the multicast service, for example, one copy is sent to the next hop IAB node, and another copy is directly multicast through the air interface. Of course, it is also possible that multiple copies are sent to multiple next hop IAB nodes.

[0257] It should be understood that the TNL address information: corresponding to the multicast service, including the IP address and the TEID. The IP address can be referred to as the multicast IP address, and the TEID can be referred to as the multicast TEID. The TNL address information and the multicast service information are in a one-to-one correspondence, for example, TMGI#1 corresponds to TNL address information#1, that is, IP address#1 and TEID#1, and TMGI#2 corresponds to TNL address information#2, that is, IP address#2 and TEID#2.

[0258] The second configuration information can include any one or a combination of the following: multicast service information, routing information, BAP address of the next hop IAB node, link configuration, and indication of whether multicast (i.e., air interface multicast) is needed.

[0259] Among them, the multicast service information: the same as the multicast service information in the first configuration information.

[0260] The routing information: the same as the routing information in the first configuration information. When the intermediate IAB node receives the first multicast service, it determines whether it needs to forward the first multicast service, that is, whether it needs to send the first multicast service to the next hop IAB node. For example, the IAB node will judge whether the BAP address in the routing information contained in the BAP layer outside the received data packet encapsulation is the same as its own BAP address, if they are the same, it means that it is the last hop IAB node, otherwise it needs to forward the first multicast service.

[0261] The BAP address of the next hop IAB node: when the intermediate IAB node determines that the first multicast service needs to be forwarded, the BAP address of the next hop IAB node corresponding to the first multicast service.

[0262] Link configuration: the intermediate IAB node forwards the first multicast service according to the link configuration when determining that the first multicast service needs to be forwarded. The link configuration includes: (1) one or more combinations of the following: logical channel identifier of the first multicast service, DRB identifier of the first multicast service, RLC backhaul channel identifier of the first multicast service; (2) one or more combinations of the following: logical channel identifier of the first multicast service forwarded to the next hop IAB node, DRB identifier of the first multicast service forwarded to the next hop IAB node, RLC backhaul channel identifier of the first multicast service forwarded to the next hop IAB node. The logical channel identifier of the first multicast service and the first multicast service have a corresponding relationship. For example, logical channel identifier #1 corresponds to multicast service #1, and logical channel identifier #2 corresponds to multicast service #2. Then the intermediate IAB node can determine the corresponding multicast service information according to the logical channel identifier.

[0263] Indication of whether multicast is needed: the intermediate IAB node can determine whether to perform air interface multicast of the first multicast service according to the indication.

[0264] When the MT of the IAB node receives the first multicast service from the previous hop node, it determines whether to forward the first multicast service according to the corresponding relationship between the logical channel identifier of the first multicast service and the routing information. In particular, the MT of the IAB node needs to forward the first multicast service received from the previous hop node to the DU of the IAB node through an internal interface, so that the DU of the IAB node can determine to which next hop IAB node and through which backhaul to forward the first multicast service according to the next hop IAB node and the link configuration. At the same time, the MT of the IAB node also forwards the indication of whether multicast is needed to the DU of the IAB node. The DU of the IAB node determines whether to multicast the first multicast service through the air interface according to the indication. When the first multicast service needs to be multicast through the air interface, the IAB node can determine the multicast service channel corresponding to the first multicast service according to the multicast service information corresponding to the first multicast service. The first multicast service needs to be multicast through the air interface, which means that the IAB node needs to copy multiple copies of the first multicast service, for example, one copy is sent to the next hop IAB node, and another copy is directly multicast through the air interface. Of course, it is also possible to send multiple copies to multiple next hop IAB nodes.

[0265] The third configuration information can include any one or more combinations of the following: multicast service information and multicast IP address. The multicast service information is the same as the multicast service information in the first configuration information. The multicast service information and the multicast IP address correspond, and the IAB node can obtain the corresponding multicast service information according to the IP address contained in the data packet, so as to multicast the first multicast service through the air interface according to the multicast data channel corresponding to the multicast service information.

[0266] Optionally, the host CU can send the second configuration information and the third configuration information through an RRC message, or send the second configuration information and the third configuration information through an F1 interface message. That is, the CU can send a first RRC message to the intermediate node, and the first RRC message can include the second configuration information; the CU can also send the second configuration information to the intermediate node through an F1 interface between the CU and the intermediate node. Similarly, the CU can send a second RRC message to the last-hop IAB node, and the second RRC message can include the third configuration information; the CU can also send the third configuration information to the last-hop IAB node through an F1 interface between the CU and the last-hop IAB node. The second configuration information and the third configuration information can also be partially sent through an RRC message and partially sent through an F1 interface message.

[0267] It should be noted that in the method, the intermediate IAB node can also be referred to as a first IAB node, and the last-hop IAB node can also be referred to as a second IAB node.

[0268] After the configuration process of S910 is completed, the sending process of user plane data is introduced below.

[0269] S920, the host CU sends the first multicast service to the host DU.

[0270] After the host CU receives the first multicast service sent by the core network or the multicast server, the host CU sends the first multicast service to the DU through the user plane tunnel established between the CU and the DU for the first multicast service. After the DU receives the first multicast service, the DU determines whether to multicast the first multicast service over the air interface, determines the next-hop IAB node, and determines the logical channel between the host DU and the next-hop IAB node for transmitting the first multicast service according to the first configuration information.

[0271] For example, the DU receives a multicast service and IP, UDP and GTP-U headers encapsulated outside the multicast service, the GTP-U header includes a TEID, and the TNL address is composed of the IP address contained in the IP header and the TEID contained in the GTP-U header. If the TNL address information is the TNL address information corresponding to the multicast service information in the first configuration information, the DU can first determine that the multicast service is the first multicast service. Then the DU can perform the following operations according to the first configuration information: (1) If the indication of whether multicast is needed indicates that multicast is needed, multicast the first multicast service on the multicast service channel corresponding to the first multicast service, otherwise do not multicast the first multicast service. (2) Add the routing information corresponding to the multicast service information in the first configuration information in the BAP header corresponding to the first multicast service. (3) Determine the C-RNTI of the MT of the next hop IAB node in the air interface according to the BAP address of the next hop IAB node corresponding to the first multicast service, and learn which logical channel to send the first multicast service to the MT of the next hop IAB node according to the link configuration.

[0272] S930, the host DU sends the first multicast service to the next hop IAB node. For ease of understanding, the next hop IAB node here is denoted as: IAB node 1.

[0273] After the IAB node 1 receives the first multicast service, it determines whether to multicast the first multicast service in the air interface and whether to send the first multicast service to the next hop IAB node according to the second configuration information, and determines the information of the next hop IAB node and the information of the IAB node 1 and the next hop IAB node for transmitting the first multicast service (i.e., logical channel information) in the case of forwarding the first multicast service.

[0274] For example, after the IAB node 1 (i.e., the MT of the IAB node 1) receives the first multicast service, since the BAP address contained in the routing information in the BAP header corresponding to the first multicast service (i.e., the BAP header used to encapsulate the first multicast service) is different from its own BAP address, it is considered that the IAB node 1 is not the last hop IAB node. The IAB node 1 determines whether to multicast the first multicast service in the air interface according to the indication of whether multicast is needed in the second configuration information, and if multicast is needed, multicasts the first multicast service on the multicast service channel corresponding to the first multicast service, otherwise does not multicast the first multicast service. And the IAB node 1 determines the C-RNTI of the MT of the next hop IAB node in the air interface according to the BAP address of the corresponding next hop IAB node, and learns which logical channel to send the first multicast service to the MT of the next hop IAB node according to the link configuration.

[0275] S940, the IAB node 1 sends the first multicast service to the next hop IAB node. For the convenience of understanding, the next hop IAB node here is recorded as: IAB node 2.

[0276] If the IAB node 2 is an intermediate IAB node, that is, the configuration information sent by the host CU for the IAB node 2 is the second configuration information, the IAB node 2 determines whether the first multicast service needs to be air interface multicast and whether the first multicast service needs to be sent to the next hop IAB node according to the second configuration information, and determines the information of the next hop IAB node and the information (that is, the logical channel information) of the IAB node 2 and the next hop IAB node for transmitting the first multicast service in the case of needing to forward the first multicast service. If the IAB node 2 is the last hop IAB node, that is, the configuration information sent by the host CU for the IAB node 2 is the third configuration information, the IAB node 2 determines the multicast service channel corresponding to the first multicast service according to the IP address according to the third configuration information, and multicasts the first multicast service on the multicast service channel corresponding to the first multicast service.

[0277] For example, if the configuration information sent by the host CU for the IAB node 2 is the second configuration information, since the BAP address contained in the routing information in the BAP header of the first multicast service is different from the own BAP address, the IAB node 2 considers that it is not the last hop IAB node. The IAB node 2 determines whether the first multicast service needs to be air interface multicast according to the indication of whether multicast is needed in the second configuration information, and multicasts the first multicast service on the multicast service channel corresponding to the first multicast service if multicast is needed, otherwise does not multicast the first multicast service. And the IAB node 2 determines the C-RNTI of the MT of the next hop IAB node in the air interface according to the BAP address of the corresponding next hop IAB node, and knows which logical channel to send the first multicast service to the MT of the next hop IAB node according to the link configuration. If the configuration information sent by the host CU for the IAB node 2 is the third configuration information, the IAB node 2 determines the multicast service channel corresponding to the first multicast service according to the IP address according to the third configuration information, and multicasts the first multicast service on the multicast service channel corresponding to the first multicast service.

[0278] S950, the IAB node 2 multicasts the first multicast service on the multicast service channel corresponding to the first multicast service.

[0279] Taking the IAB node 2 as the last hop IAB node as an example, after receiving the first multicast service, the IAB node 2 determines the multicast service channel corresponding to the first multicast service according to the IP address, and multicasts the first multicast service on the multicast service channel corresponding to the first multicast service.

[0280] In summary, according to the method for multicast communication provided in the present application, the host CU configures the corresponding multicast configuration information to the host DU, the intermediate IAB node and the last-hop IAB node, so that the host DU, the intermediate IAB node and the last-hop IAB node can implement multicast of multicast services according to the corresponding configuration information.

[0281] Figure 11 is a schematic diagram of another method for multicast communication provided in the present application. The method is described below.

[0282] I. Establishing a user plane tunnel

[0283] The host CU (i.e., the first network device) establishes at least one user plane tunnel between the host CU and the host DU (i.e., the second network device), and establishes at least one user plane tunnel between the host CU and the DU of each IAB node.

[0284] Each IAB node refers to each IAB node on the path from the host CU to the first terminal device. For example, taking the architecture shown in Figure 12 Each IAB node refers to IAB node 1 and IAB node 2.

[0285] For ease of understanding, the user plane tunnel between the host CU and the host DU is denoted as: a first user plane tunnel. The user plane tunnel between the host CU and the IAB node is denoted as: a second user plane tunnel. It can be understood that each IAB node corresponds to at least one second user plane tunnel.

[0286] It should be understood that the first user plane tunnel and the second user plane tunnel are both wireless F1 interface user plane tunnels. How to establish a user plane tunnel between a CU and a DU can be referred to the prior art, which will not be described in detail here.

[0287] Each user plane tunnel corresponds to a multicast service. Through at least one first user plane tunnel, the host CU can send at least one multicast service to the host DU. For any IAB node, through at least one second user plane tunnel corresponding to the IAB node, the host CU can send at least one multicast service to the DU of the IAB node. The host CU can determine which multicast services to send to the IAB node according to the operator policy, or can determine which multicast services to send to each IAB node according to the interested multicast services reported by the terminal device to the CU, in combination with the IAB node accessed by the terminal device.

[0288] For example, Figure 12As shown in the networking architecture, if the terminal device accessing the host DU is interested in only two multicast services, the host CU and the host DU can establish user plane tunnels for transmitting the two multicast services, denoted as: user plane tunnel 1 and user plane tunnel 2. If the terminal device accessing the DU of the IAB node 1 is interested in only one multicast service, the host CU and the DU of the IAB node 1 can establish a user plane tunnel for transmitting the multicast service, denoted as: user plane tunnel 3. If the terminal device accessing the DU of the IAB node 2 is interested in only two multicast services, the host CU and the DU of the IAB node 2 can establish user plane tunnels for transmitting the two multicast services, denoted as: user plane tunnel 4 and user plane tunnel 5. The five multicast services corresponding to the user plane tunnels 1-5 can be all the same or partially the same, or all different.

[0289] II. Transmitting multicast data through user plane tunnels.

[0290] The host CU sends at least one first multicast service to the host DU through at least one first user plane tunnel, the at least one first user plane tunnel corresponding to the at least one first multicast service in one-to-one manner. The host DU multicasts the at least one first multicast service to the terminal devices accessing the host DU.

[0291] The host CU sends at least one second multicast service to the DU of the corresponding IAB node through at least one second user plane tunnel corresponding to each IAB node, the at least one second user plane tunnel corresponding to the at least one second multicast service in one-to-one manner. Each IAB node multicasts the at least one second multicast service to the terminal devices accessing the IAB node through the air interface.

[0292] Referring to Figure 12 , the host CU transmits multicast service 1 and multicast service 2 through user plane tunnel 1 and user plane tunnel 2 respectively, and the host DU receives the multicast service 1 and the multicast service 2 and multicasts the multicast service 1 and the multicast service 2 through the corresponding multicast service channel. The host CU transmits multicast service 3 corresponding to the IAB node 1 through user plane tunnel 3, and the DU of the IAB node 1 receives the multicast service 3 and multicasts the multicast service 3. The host CU transmits multicast service 4 and multicast service 5 corresponding to the IAB node 2 through user plane tunnel 4 and 5 respectively, and the DU of the IAB node 2 receives the multicast service 4 and the multicast service 5, multicasts the multicast service 4 through the multicast service channel corresponding to the multicast service 4, and multicasts the multicast service 5 through the multicast service channel corresponding to the multicast service 5.

[0293] In summary, according to the multicast method provided in the present application, a user plane tunnel between the host CU and the host DU is established for the multicast service interested by the terminal device accessing the host DU, and a user plane tunnel between the host CU and the DU of the IAB node is established for the multicast service interested by the terminal device accessing the DU of each IAB node, so that the multicast mechanism under the IAB architecture can be implemented.

[0294] Figure 13 is a schematic diagram of another method for multicast communication provided in the present application. The method 1200 is described below.

[0295] S1201, the host CU (i.e., the first network device) sends at least one multicast service information to each IAB node on the path between the host CU and the first terminal device respectively.

[0296] Specifically, the host CU sends the at least one multicast service information to the MT of each IAB node or to the DU of each IAB node. For example, the host CU can send the at least one multicast service information through the RRC message between the host CU and the MT of the IAB node or the F1 interface message between the host CU and the DU of the IAB node. The at least one multicast service information is the information of at least one multicast service that the corresponding IAB node needs to listen to and multicast, and the specific form of the multicast service information can be referred to the description in S310 above. If an IAB node is not the last hop IAB node, the at least one multicast service that the IAB node needs to listen to and multicast is the set of multicast services that the next hop IAB node needs to listen to and multicast and the multicast services that the terminal device accessing the IAB node through the access link needs to listen to. If an IAB node is the last hop IAB node, the at least one multicast service that the IAB node needs to listen to and multicast is the multicast service that the terminal device accessing the IAB node through the access link needs to listen to.

[0297] For example, the networking architecture shown in Figure 14 is described. Referring to Figure 14 , the first terminal device can be any one of the UE3, the UE4 and the UE5, and each IAB node on the path between the host CU and the first terminal device includes the IAB node 1 and the IAB node 2. The host CU sends at least one multicast service information to the MT (i.e., the MT1) of the IAB node 1 and the MT (i.e., the MT2) of the IAB node 2 respectively. For ease of understanding, the at least one multicast service information sent by the host CU to the MT1 is denoted as: multicast service information set 1; and the at least one multicast service information sent by the host CU to the MT2 is denoted as: multicast service information set 2. Figure 14In the specific implementation, the terminal devices accessing the DU (i.e., DU1) of the IAB node 1 are UE1 and UE2, and the terminal devices accessing the DU (i.e., DU2) of the IAB node 2 are UE3, UE4 and UE5. The multicast service information set 2 indicates a set of multicast services that the IAB node 2 needs to listen to and multicast, i.e., a set of multicast services that UE3, UE4 and UE5 need to listen to; the multicast service information set 1 indicates a set of multicast services that the IAB node 1 needs to listen to and multicast, i.e., a set of multicast services that UE1 and UE2 need to listen to and a set of multicast services that the IAB node 2 needs to listen to and multicast. For example, if the multicast services that UE3, UE4 and UE5 need to listen to are multicast service 4 to multicast service 8, and the multicast services that UE1 and UE2 need to listen to are multicast service 1 to multicast service 5, then the IAB node 1 needs to listen to and multicast multicast service 1 to multicast service 8, and the IAB node 2 needs to listen to and multicast multicast service 4 to multicast service 8.

[0298] S1202, each IAB node determines configuration information of the multicast control channel according to the corresponding at least one multicast service information.

[0299] After the MT of any IAB node receives the at least one multicast service information sent by the host CU, the at least one multicast service information is sent to the DU of the IAB node, and the DU of the IAB node generates configuration information of the multicast control channel according to the at least one multicast service information. Alternatively, after the DU of the IAB node receives the at least one multicast service information sent by the host CU, the configuration information of the multicast control channel is generated.

[0300] Specifically, how to generate the configuration information of the multicast control channel according to the multicast service information can refer to step S520 in the foregoing.

[0301] S1203, each IAB node sends the determined configuration information of the multicast control channel to the host CU.

[0302] For example, referring to Figure 13 After DU1 and DU2 respectively determine the configuration information of the multicast control channel, the configuration information of the multicast control channel is sent to the host CU. For example, the DU of the IAB node sends the configuration information of the multicast control channel to the host CU through the F1 interface. Alternatively, the DU of the IAB node sends the configuration information of the multicast control channel to the MT of the IAB node through an internal interface, and the MT of the IAB node sends the configuration information of the multicast control channel to the host CU through an uplink RRC message.

[0303] S1204, the host CU determines system information of each IAB node according to the configuration information of the multicast control channel reported by each IAB node.

[0304] The system information of any IAB node includes configuration information of a multicast control channel corresponding to the IAB node.

[0305] S1205, the host CU sends corresponding system information to each IAB node.

[0306] For example, the host CU can send the system information to the DU of the corresponding IAB node through the F1 interface.

[0307] S1206, each IAB node broadcasts the received system information.

[0308] For example, IAB node 1 broadcasts the received system information, and UE1, UE2 and IAB node 2 can receive the system information. IAB node 2 broadcasts the received system information, and UE3, UE4 and UE5 can receive the system information.

[0309] S1207, each IAB node sends configuration information of at least one multicast service channel on the multicast control channel according to the configuration information of the multicast control channel in the received system information.

[0310] It should be understood that the at least one multicast service channel configured by the configuration information of the at least one multicast service channel sent by each IAB node is used to transmit at least one multicast service corresponding to the IAB node.

[0311] It should be noted that before S1208, the host DU (i.e., the second network device) can obtain the corresponding system information by interacting with the host CU through the method 500 described above, and can send configuration information of at least one multicast service channel on the multicast control channel according to the configuration information of the multicast control channel in the system information, the at least one multicast service channel being used to transmit at least one multicast service that the host DU needs to multicast, and the at least one multicast service that the DU needs to multicast including at least one multicast service that IAB node 1 needs to listen to and multicast. For example, if IAB node 1 needs to listen to and multicast multicast service 1 to multicast service 8, the DU needs to multicast multicast service 1 to multicast service 8.

[0312] The control plane message flow related to multicast channels ends by S1207. Next is the user plane flow.

[0313] S1208, the host CU sends at least one multicast service to the host DU. The at least one multicast service is at least one multicast service that the host DU needs to multicast.

[0314] For example, the host CU sends multicast service 1 to multicast service 8 to the host DU.

[0315] S1209, the host DU multicasts the at least one multicast service received by the host DU according to the configuration information of the at least one multicast service channel corresponding to the host DU.

[0316] For example, the host DU multicasts the multicast service 1 to the multicast service 8. Correspondingly, the MT 1 of the IAB node 1 can receive the multicast service 1 to the multicast service 8.

[0317] S1210, each IAB node sends the at least one multicast service corresponding to the IAB node according to the configuration information of the at least one multicast service channel corresponding to the IAB node.

[0318] For example, after the MT 1 of the IAB node 1 receives the multicast service 1 to the multicast service 8 multicasted by the host DU, the MT 1 sends the multicast service 1 to the multicast service 8 to the DU 1 of the IAB node 1, and the DU 1 multicasts the multicast service 1 to the multicast service 8. The UE 1 and the UE 2 listen to the multicast service 1 to the multicast service 5, and the MT 2 of the IAB node 2 listens to the multicast service 4 to the multicast service 8. The IAB node 2 sends the received multicast service 4 to the multicast service 8 to the DU 2 of the IAB node 2, and the DU 2 multicasts the multicast service 4 to the multicast service 8. Correspondingly, the UE 3, the UE 4 and the UE 5 listen to the multicast service 4 to the multicast service 8.

[0319] In summary, according to the method for multicast communication provided in the present application, the host CU configures the multicast service that needs to be multicast by the host DU and the multicast service that needs to be received, listened to and multicast by each IAB node, so that the host DU can multicast the multicast service according to the configuration of the host CU, and each IAB node can listen to and multicast the multicast service according to the configuration of the host CU, thereby realizing the multicast communication of the IAB architecture.

[0320] The above, in combination with Figures 3 to 14 The method provided by the embodiments of the present application is described in detail. In the following, in combination with Figures 15 to 17 The device provided by the embodiments of the present application is described in detail.

[0321] Figure 15 is a schematic block diagram of the communication device provided by the embodiments of the present application. As Figure 15 shown, the communication device 2000 can include a transceiver unit 2010 and / or a processing unit 2020.

[0322] The transceiver unit 2010 can be used to send information to other devices or equipment, or receive information from other devices or equipment. The processing unit 2020 can be used to perform part of the processing of the device.

[0323] In an implementation, the communication apparatus 2000 corresponds to the first network device (i.e., the CU) in the method 300. The communication apparatus 2000 can be the first network device or a chip configured in the first network device, which can include units for performing operations performed by the first network device.

[0324] In particular, the transceiver 2010 is configured to send first information to a second network device, the first information indicating an association relationship between multicast service information and a first terminal device; the transceiver 2010 is further configured to receive second information from the second network device; the processing unit 2020 is configured to generate a configuration message according to the second information, the configuration message indicating an association relationship between the multicast service information and a first logical channel, the first logical channel being a logical channel of the first terminal device; the transceiver 2010 is further configured to send the configuration message to the first terminal device; the first network device has a packet data convergence protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function, and the second network device has a radio link control layer function, a medium access control layer function, and a physical layer function.

[0325] Optionally, the second information indicates the association relationship between the multicast service information and the first logical channel.

[0326] Optionally, the first information indicating the association relationship between multicast service information and a first terminal device comprises: the first information indicating an association relationship between the multicast service information and a first data radio bearer (DRB) of the first terminal device; and the second information indicating an association relationship between the first DRB and a first logical channel of the first terminal device.

[0327] Optionally, the multicast service information comprises one or more of the following: a multicast area identifier, a temporary mobile group identifier (TMGI), a session identifier, and a group radio network temporary identifier (G-RNTI).

[0328] Optionally, the configuration message is a radio resource control (RRC) reconfiguration message.

[0329] In an implementation, the communication apparatus 2000 corresponds to the second network device (i.e., the DU) in the method 300. The communication apparatus 2000 can be the second network device or a chip configured in the second network device, which can include units for performing operations performed by the second network device.

[0330] Specifically, the transceiver 2010 is configured to receive first information from a first network device, the first information indicating an association relationship between multicast service information and a first terminal device; and the transceiver 2010 is further configured to send second information to the first network device, the second information being used for determining a configuration message, the configuration message indicating an association relationship between the multicast service information and a first logical channel, the first logical channel being a logical channel of the first terminal device; the first network device has a packet data convergence protocol layer function, a service data adaptation protocol layer function and a radio resource control layer function, and the second network device has a radio link control layer function, a medium access control layer function and a physical layer function.

[0331] Optionally, the second information indicates the association relationship between the multicast service information and the first logical channel.

[0332] Optionally, the first information indicating the association relationship between the multicast service information and the terminal device comprises: the first information indicating an association relationship between the multicast service information and a first data radio bearer DRB of the first terminal device; and the second information indicating an association relationship between the first DRB and a first logical channel of the first terminal device.

[0333] Optionally, the multicast service information comprises one or more of the following: a multicast area identifier, a temporary mobile group identifier TMGI, a session identifier and a group radio network temporary identifier G-RNTI.

[0334] In an implementation manner, the communication apparatus 2000 corresponds to the terminal device in the method 300. The communication apparatus 2000 can be a terminal device or a chip configured in the terminal device, and can comprise units for performing operations performed by the terminal device.

[0335] Specifically, the transceiver 2010 is configured to receive a configuration message from a first network device, the configuration message indicating an association relationship between multicast service information and a first logical channel of the terminal device; and the transceiver 2010 is further configured to receive multicast service corresponding to the multicast service information on the first logical channel according to the configuration message.

[0336] Optionally, the multicast service information comprises one or more of the following: a multicast area identifier, a temporary mobile group identifier TMGI, a session identifier and a group radio network temporary identifier G-RNTI.

[0337] Optionally, the configuration message is a radio resource control RRC reconfiguration message.

[0338] In an implementation, the communication apparatus 2000 corresponds to the first network device (i.e., the CU) in the method 400 described above. The communication apparatus 2000 can be the first network device or a chip configured in the first network device, which can include units for performing operations performed by the first network device.

[0339] In particular, the transceiver 2010 is configured to send multicast service information to a second network device; the transceiver 2010 is also configured to receive configuration information of a multicast control channel from the second network device, the configuration information being determined according to the multicast service information; the processing unit 2020 is configured to generate system information according to the configuration information, the system information including the configuration information; the transceiver 2010 is also configured to send the system information to the second network device; the first network device has a packet data convergence protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function; and the second network device has a radio link control layer function, a medium access control layer function, and a physical layer function.

[0340] Optionally, the system information is a system information block (SIB) 13 or a SIB 20.

[0341] Optionally, the transceiver 2010 is also configured to send a multicast service type corresponding to the multicast service information to the second network device.

[0342] Optionally, the transceiver 2010 is also configured to send a first network device side TNL address corresponding to the multicast service information to the second network device, where the TNL address includes an IP address and a TEID.

[0343] Optionally, the multicast service information includes one or more of the following: a multicast area identifier, a temporary mobile group identifier (TMGI), a session identifier, and QoS information.

[0344] Optionally, the configuration information includes one or more of the following: a repetition period of the multicast control channel, an offset of the multicast control channel, a modification period of the multicast control channel, subframe allocation information of the multicast control channel, multicast broadcast single frequency network (MBSFN) area configuration information, a notification indication, and a non-MBSFN area length.

[0345] Optionally, the transceiver 2010 is specifically configured to send a session start request message to the second network device, the session start request message including the multicast service information; or send a session modification request message to the second network device, the session modification request message including the multicast service information.

[0346] In an implementation, the communication apparatus 2000 corresponds to the second network device (i.e., DU) in the method 400. The communication apparatus 2000 can be the second network device or a chip configured in the second network device, which can include units for performing operations performed by the second network device.

[0347] In particular, the transceiver 2010 is configured to receive multicast service information from a first network device; the processing unit 2020 is configured to determine configuration information of a multicast control channel according to the multicast service information; the transceiver 2010 is further configured to send the configuration information to the first network device; the transceiver 2010 is further configured to receive system information from the first network device, the system information including the configuration information; the transceiver 2010 is further configured to broadcast the system information; the first network device has a packet data convergence protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function, and the second network device has a radio link control layer function, a medium access control layer function, and a physical layer function.

[0348] Optionally, the system information is a system information block (SIB) 13 or SIB 20.

[0349] Optionally, the multicast service information includes one or more of the following: a multicast area identifier, a temporary mobile group identifier (TMGI), a session identifier, and quality of service (QoS) information.

[0350] Optionally, the configuration information includes one or more of the following: a repetition period of the multicast control channel, an offset of the multicast control channel, a modification period of the multicast control channel, subframe allocation information of the multicast control channel, multicast broadcast single frequency network (MBSFN) area configuration information, a notification indication, and a non-MBSFN area length.

[0351] Optionally, the transceiver 2010 is specifically configured to receive a session start request message from the first network device, the session start request message including the multicast service information; or receive a session modification request message from the first network device, the session modification request message including the multicast service information.

[0352] In an implementation, the communication apparatus 2000 corresponds to the IAB node in the method 1200. The communication apparatus 2000 can be the IAB node or a chip configured in the IAB node, which can include units for performing operations performed by the IAB node.

[0353] Specifically, the transceiver 2010 is configured to receive at least one multicast service information from a first network device, the at least one multicast service information indicating at least one multicast service that the IAB node needs to listen to and multicast, the first network device being a centralized unit Donor-CU of a donor node; the transceiver 2010 is further configured to receive the at least one multicast service from a parent node of the IAB node according to the at least one multicast service information; and the transceiver 2010 is further configured to multicast the at least one multicast service.

[0354] Optionally, the processing unit 2020 is configured to determine configuration information of a multicast control channel according to the at least one multicast service information; the transceiver 2010 is further configured to send the configuration information of the multicast control channel to the first network device; the transceiver 2010 is further configured to receive system information from the first network device, the system information including the configuration information of the multicast control channel; the transceiver 2010 is further configured to broadcast the system information; and the transceiver 2010 is further configured to send configuration information of at least one multicast service channel on the multicast control channel according to the configuration information of the multicast control channel, the at least one multicast service channel being used to multicast the at least one multicast service.

[0355] Optionally, the multicast service information includes one or more of the following: a temporary mobile group identity TMGI, a multimedia broadcast multicast service MBMS session identity, a group radio network temporary identifier G-RNTI, and a logical channel identifier.

[0356] Optionally, the communication apparatus 2000 includes a mobile terminal MT and a distributed unit DU; and the transceiver 2010 is specifically configured to receive an RRC message from the first network device through the MT, the RRC message including the at least one multicast service information; or receive a first interface message from the first network device through the DU, the first interface message including the at least one multicast service information.

[0357] In an implementation manner, the communication apparatus 2000 corresponds to the first network device (i.e., the CU of the donor node) in the method 1200 described above. The communication apparatus 2000 can be the first network device or a chip configured in the first network device, and can include units for performing operations performed by the first network device.

[0358] Specifically, the transceiver 2010 is configured to transmit, to each integrated access and backhaul, IAB, node on a path between the communication apparatus 2000 and a first terminal device, at least one groupcast service information of the corresponding IAB node, the at least one groupcast service information indicating at least one groupcast service that the corresponding IAB node needs to listen to and groupcast; and the transceiver 2010 is further configured to transmit, to a second network device, the at least one groupcast service that each IAB node needs to listen to and groupcast, the second network device being a centralized unit, Donor-CU, of the donor node.

[0359] Optionally, the transceiver 2010 is further configured to receive configuration information of a groupcast control channel of each IAB node, wherein the configuration information of the groupcast control channel of any IAB node is determined by the IAB node according to the corresponding at least one groupcast service information; the processing unit 2020 is configured to determine system information of each IAB node according to the configuration information of the groupcast control channel of each IAB node, the system information of any IAB node including the configuration information of the groupcast control channel of the IAB node; and the transceiver 2010 is further configured to transmit the system information to each IAB node.

[0360] Optionally, the groupcast service information includes one or more of the following: a temporary mobile group identity, TMGI, a multimedia broadcast multicast service, MBMS, session identity, a group radio network temporary identity, G-RNTI, and a logical channel identity.

[0361] Optionally, the IAB node includes a mobile terminal, MT, and a distributed unit, DU; and the transceiver 2010 is specifically configured to transmit, to a mobile terminal of each IAB node, an RRC message including the at least one groupcast service information through the MT, or transmit, to a mobile terminal of each IAB node, a first interface message including the at least one groupcast service information through the DU.

[0362] In an implementation manner, the communication apparatus 2000 corresponds to the second network device (i.e., the DU of the donor node) in the method 900 described above. The communication apparatus 2000 can be the second network device or a chip configured in the second network device, and can include units for performing operations performed by the second network device.

[0363] Specifically, the transceiver 2010 is configured to receive a first multicast service from a first network device, the first multicast service comprising a transport network layer (TNL) address corresponding to the first multicast service, the first network device being a centralized unit (Donor-CU) of a donor node; and the transceiver 2010 is further configured to forward, according to first configuration information, the first multicast service to a next-hop integrated access and backhaul (IAB) node.

[0364] Optionally, the transceiver 2010 is further configured to multicast, according to the first configuration information, the first multicast service to terminal devices accessing a second network device, in a case where it is determined that the first multicast service needs to be multicast to the terminal devices accessing the second network device.

[0365] Optionally, the processing unit 2020 is further configured to: add, according to the first configuration information, routing information corresponding to the first multicast service in a backhaul adaptation protocol (BAP) header corresponding to the first multicast service, and determine a second link configuration according to the first configuration information; and the transceiver 2010 is specifically configured to send, through the second link, the first multicast service to the next-hop IAB node, the BAP header corresponding to the first multicast service comprising the routing information.

[0366] Optionally, the transceiver 2010 is further configured to receive the first configuration information from the first network device.

[0367] In an implementation manner, the communication apparatus 2000 corresponds to the first IAB node in the method 900 described above. The communication apparatus 2000 can be the first IAB node or a chip configured in the first IAB node, and can include units for performing operations performed by the first IAB node.

[0368] Specifically, the transceiver 2010 is configured to receive a first multicast service; and the processing unit 2020 is configured to determine, according to second configuration information, whether the first multicast service needs to be forwarded to other IAB nodes; the processing unit 2020 is further configured to, in a case where the first multicast service needs to be forwarded to other IAB nodes, determine, according to the second configuration information, a next-hop IAB node and a first backhaul link; and the transceiver 2010 is further configured to forward, through the first backhaul link, the first multicast service to the next-hop IAB node.

[0369] Optionally, the processing unit 2020 is further configured to determine, according to the second configuration information, whether the first multicast service needs to be multicast to terminal devices accessing the first IAB node; and the transceiver 2010 is further configured to multicast the first multicast service on a multicast service channel corresponding to the first multicast service in a case where the processing unit 2020 determines that the first multicast service needs to be multicast to terminal devices accessing the first IAB node.

[0370] Optionally, the transceiver 2010 is further configured to receive the second configuration information from a first network device, the first network device being a centralized unit Donor-CU of a host node.

[0371] Optionally, the second configuration information includes one or more of the following: multicast service information corresponding to the first multicast service, routing information, a BAP address of the next-hop node, the first link configuration, and an indication of whether the first multicast service needs to be multicast to terminal devices accessing the first IAB node; wherein the routing information includes a BAP address of a last-hop IAB node, and the routing information is used by the first IAB node to determine whether the first multicast service needs to be forwarded to other IAB nodes.

[0372] Optionally, the first backhaul link configuration is a logical channel between the first IAB node and the next-hop IAB node for forwarding the first multicast service.

[0373] Optionally, the multicast service information includes one or more of the following: a temporary mobile group identity TMGI, a multimedia broadcast multicast service MBMS session identity, a group radio network temporary identifier G-RNTI, and a logical channel identifier.

[0374] In an implementation manner, the communication apparatus 2000 corresponds to the second IAB node in the method 900 described above. The communication apparatus 2000 can be the second IAB node or a chip configured in the second IAB node, and can include units for performing operations performed by the second IAB node.

[0375] Specifically, the transceiver 2010 is configured to receive a first multicast service from a previous-hop IAB node, the first multicast service comprising a routing identifier and a multicast Internet Protocol (IP) address; the processing unit 2020 is configured to determine whether the first multicast service needs to be forwarded to other IAB nodes according to the routing identifier; the processing unit 2020 is further configured to, in a case where the transceiver 2010 does not need to forward the first multicast service, determine a multicast service channel corresponding to the first multicast service according to the multicast IP address and third configuration information, wherein the third configuration information is used to indicate a correspondence between multicast service information of the first multicast service and the multicast IP address; and the transceiver 2010 is further configured to multicast the first multicast service on the multicast service channel corresponding to the first multicast service.

[0376] Optionally, the transceiver 2010 is further configured to receive the third configuration information from a first network device, the first network device being a centralized unit (CU) of a donor node.

[0377] Optionally, the transceiver 2010 is further configured to receive an RRC message from the first network device, the RRC message comprising the third configuration information; or receive a first interface message from the first network device, the first interface message comprising the third configuration information.

[0378] Optionally, the multicast service information comprises one or more of the following: a temporary mobile group identity (TMGI), a multimedia broadcast multicast service (MBMS) session identity, a group radio network temporary identifier (G-RNTI), and a logical channel identifier.

[0379] In an implementation manner, the communication apparatus 2000 corresponds to the first network device (i.e., the CU of the donor node) in the method 900 described above. The communication apparatus 2000 can be the first network device or a chip configured in the first network device, and can comprise units configured to perform operations performed by the first network device.

[0380] Specifically, the transceiver 2010 is configured to send first configuration information to a second network device, send second configuration information to each first IAB node on a path between the communication apparatus 2000 and a first terminal device, and send third configuration information to a third IAB node, the second network device being a distributed unit Donor-DU of the host node; the first configuration information, the second configuration information, and the third configuration information are used to send a first multicast service; the first configuration information is used for the second network device to determine whether the first multicast service needs to be multicast to a terminal device group accessing the second network device, and first IAB nodes receiving the first multicast service and link configuration used for sending the first multicast service to the first IAB nodes receiving the first multicast service; the second configuration information is used for the first IAB node to determine whether the first multicast service needs to be multicast to a terminal device group accessing the first IAB node, and other first IAB nodes receiving the first multicast service and link configuration used for sending the first multicast service to the other first IAB nodes receiving the first multicast service; and the third configuration information is used for the second IAB node to determine a multicast service channel corresponding to the first multicast service.

[0381] It should be understood that the communication apparatus 2000 corresponds to each node in the method shown in Figure 11 and can include units for performing operations performed by the corresponding nodes in the method shown in Figure 11 .

[0382] It should also be understood that the specific processes of each unit performing the corresponding steps in the above method embodiments have been described in detail in the above method embodiments, and for the sake of brevity, will not be repeated here.

[0383] Figure 16 is a structural schematic diagram of a network device provided by an embodiment of the present application, which can be a structural schematic diagram of a base station. As Figure 16 shown, the network device can implement the functions of the IAB node in the above method embodiments, the DU 3101 in the network device can also implement the functions of the DU or the second network device in the above method embodiments, and the CU 3102 in the network device can also implement the functions of the CU or the first network device in the above method embodiments.

[0384] The network device 3000 can include one or more DUs 3101 and one or more CUs 3102. The CU 3102 can communicate with a next generation core network (NG core, NC). The DU 3101 can include at least one antenna 31011, at least one radio frequency unit 31012, at least one processor 31013, and at least one memory 31014. The DU 3101 part is mainly used for the transceiving of radio frequency signals and the conversion between radio frequency signals and baseband signals, and part of the baseband processing. The CU 3102 can include at least one processor 31022 and at least one memory 31021. The CU 3102 and the DU 3101 can communicate through an interface, wherein the control plane interface can be Fs-C, such as F1-C, and the user plane interface can be Fs-U, such as F1-U.

[0385] The CU 3102 part is mainly used for baseband processing, controlling the base station, etc. The DU 3101 and the CU 3102 can be physically arranged together or physically separated, that is, a distributed base station. The CU 3102 is the control center of the base station, also known as the processing unit, mainly used for completing the baseband processing function. For example, the CU 3102 can be used to control the base station to perform the operation process of the base station in the above method embodiment.

[0386] Specifically, the baseband processing on the CU and the DU can be divided according to the protocol layer of the wireless network, for example, the functions of the packet data convergence protocol (PDCP) layer and above protocol layers are arranged on the CU, and one or more protocol layers in the protocol layers below the PDCP, such as the radio link control (RLC) layer and the medium access control (MAC) layer, are arranged on the DU. For another example, the CU implements the functions of the radio resource control (RRC) and the packet data convergence protocol (PDCP) layer, and the DU implements the functions of the radio link control (RLC), the MAC, and the physical (PHY) layer.

[0387] In addition, the network device 3000 can alternatively include one or more radio units (RUs), one or more DUs, and one or more CUs. The DU can include at least one processor 31013 and at least one memory 31014, the RU can include at least one antenna 31011 and at least one radio frequency unit 31012, and the CU can include at least one processor 31022 and at least one memory 31021.

[0388] In one example, the CU 3102 can be composed of one or more boards, and the boards can collectively support a single-access-indicated wireless access network (e.g., a 5G network) or separately support wireless access networks of different access modes (e.g., an LTE network, a 5G network, or other networks). The memory 31021 and the processor 31022 can serve one or more boards. That is, the memory and the processor can be separately arranged on each board. Alternatively, multiple boards can share the same memory and processor. In addition, each board can be provided with necessary circuits.

[0389] Figure 17 is a structural schematic diagram of a terminal device 4000 provided by an embodiment of the present application. The terminal device 4000 can perform the functions of the terminal device in the above method embodiments. As shown in Figure 17 The terminal device 4000 includes a processor 4010 and a transceiver 4020. Optionally, the terminal device 4000 further includes a memory 4030. The processor 4010, the transceiver 4020, and the memory 4030 can communicate with each other through internal connection paths, transfer control and / or data signals, the memory 4030 is configured to store a computer program, and the processor 4010 is configured to call and run the computer program from the memory 4030 to control the transceiver 4020 to transceive signals. Optionally, the terminal device 4000 can further include an antenna 4040 for transmitting uplink data or uplink control signaling output by the transceiver 4020 through wireless signals.

[0390] The processor 4010 and the memory 4030 can be combined into a processing device, and the processor 4010 is used to execute the program code stored in the memory 4030 to implement the above functions. In specific implementation, the memory 4030 can also be integrated into the processor 4010, or independent of the processor 4010. The processor 4010 can be combined with the memory 4030 to form a processing device. Figure 15 The processing units in .

[0391] The transceiver 4020 can be used with Figure 15 The transceiver 4020 corresponds to the transceiver unit in FIG. , and may also be referred to as a transceiver unit. The transceiver 4020 may include a receiver (or receiver, receiving circuit) and a transmitter (or transmitter, transmitting circuit). The receiver is used to receive signals, and the transmitter is used to transmit signals.

[0392] It should be understood that Figure 17 The illustrated terminal device 4000 is capable of implementing the various processes involved in the terminal device in the aforementioned method embodiments. The operations and / or functions of the various modules in terminal device 4000 are respectively for implementing the corresponding processes in the aforementioned method embodiments. For details, please refer to the description of the aforementioned method embodiments; to avoid repetition, detailed descriptions are omitted here.

[0393] The processor 4010 can be used to perform the actions implemented within the terminal device described in the previous method embodiments, and the transceiver 4020 can be used to perform the actions of the terminal device sending to or receiving from the base station described in the previous method embodiments. For details, please refer to the description of the previous method embodiments, which will not be repeated here.

[0394] Optionally, the terminal device 4000 may further include a power supply 4050 for providing power to various devices or circuits in the terminal device.

[0395] In addition, in order to make the functions of the terminal device more complete, the terminal device 4000 may also include one or more of an input unit 4060, a display unit 4070, an audio circuit 4080, a camera 4090 and a sensor 4110, and the audio circuit may also include one or more of a speaker 4082, a microphone 4084, etc.

[0396] An embodiment of the present application further provides a processing device, including a processor and an interface; the processor is used to execute the method in the above method embodiment.

[0397] It should be understood that the processing device described above can be one or more chips. For example, the processing device can be a field programmable gate array (FPGA), can be an application specific integrated circuit (ASIC), can also be a system on chip (SoC), can also be a central processor unit (CPU), can also be a network processor (NP), can also be a digital signal processing circuit (digital signal processor, DSP), can also be a micro controller unit (MCU), can also be a programmable logic device (programmable logic device, PLD) or other integrated chip.

[0398] In the implementation process, each step of the above method can be completed by the integrated logic circuit of the hardware in the processor or the instruction in the form of software. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as hardware processor execution completion, or executed by a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the art such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, register, etc. The storage medium is located in the memory, and the processor reads the information in the memory, and combines the hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0399] It should be understood that the processor in the embodiments of the present application can be an integrated circuit chip with signal processing capability. In the implementation process, each step of the above method embodiment can be completed by the integrated logic circuit of the hardware in the processor or the instruction in the form of software. The processor described above can be a general processor, a digital signal processor (digital signal processor, DSP), an application specific integrated circuit (application specific integrated circuit, ASIC), a field programmable gate array (field programmable gate array, FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component.

[0400] It is to be appreciated that the memory in the embodiments of the application can be a volatile or non-volatile memory, or can include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically EPROM (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as the external cache. By way of example, and not limitation, many forms of RAM are available, for example, static RAM (SRAM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DR RAM). It is to be appreciated that the memory described herein is intended to include, without being limited to, these and any other suitable types of memory.

[0401] According to the method provided in the embodiments of the application, the application further provides a computer program product, which comprises computer program code, and when the computer program code runs on a computer, the computer is caused to execute the method on the terminal device side in any of the preceding method embodiments.

[0402] According to the method provided in the embodiments of the application, the application further provides a computer readable medium, which stores program code, and when the program code runs on a computer, the computer is caused to execute the method on the network device side in the preceding method embodiments.

[0403] According to the method provided in the embodiments of the application, the application further provides a system, which comprises a first network device and a second network device.

[0404] The embodiments of the application further provide a processing apparatus, which comprises a processor and an interface; the processor is used to execute the method of communication in any of the preceding method embodiments.

[0405] It should be understood that the processing device described above can be a chip. For example, the processing device can be a field programmable gate array (FPGA), can be a general processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, can also be a system chip (SoC), can also be a central processing unit (CPU), can also be a network processor (NP), can also be a digital signal processing circuit (DSP), can also be a micro controller unit (MCU), can also be a programmable logic device (PLD) or other integrated chip. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as hardware code processor execution, or executed by hardware and software module combination in code processor. The software module can be located in random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, register and other mature storage medium in the art. The storage medium is located in the memory, and the processor reads the information in the memory, and combines the hardware to complete the steps of the above method.

[0406] It is to be appreciated that the memory in the embodiments of the application can be volatile, nonvolatile, or a combination of both. The non-volatile memory can be, for example, read only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically EPROM (EEPROM), or flash memory. The volatile memory can be, for example, random access memory (RAM), which acts as external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DR RAM). It is to be appreciated that the system and method described herein can employ any of such memories or drives or a combination thereof.

[0407] In the embodiments described above, all or some of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or some of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or some of the processes or functions described in the embodiments of the present application are generated. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) manner. The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media sets. The available media can be magnetic media (such as floppy disk, hard disk, magnetic tape), optical media (such as high-density digital video disc (digital video disc, DVD)), or semiconductor media (such as solid state disc (solid state disc, SSD)) and the like.

[0408] The network device in each of the above device embodiments and the network device or terminal device in the method embodiments fully correspond to each other, and the corresponding steps are performed by the corresponding modules or units, for example, the communication unit (transceiver) performs the steps of receiving or transmitting in the method embodiments. Other steps except for sending and receiving can be performed by the processing unit (processor). The functions of the specific units can refer to the corresponding method embodiments. The processor can be one or more.

[0409] As used in the present specification, the terms "component," "module," "system" and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process or thread of execution and a component can be localized, either in whole or in part, in a single computer or distributed among multiple computers. In addition, these components can execute from various computer-readable media having various data structures stored thereon. The components can communicate by way of local or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, or across the Internet with another system, e.g., via an application program interface or other means).

[0410] It should be understood that the "embodiments" mentioned throughout the specification mean that the specific features, structures or characteristics related to the embodiments are included in at least one of the embodiments of the present application. Therefore, the various embodiments throughout the specification do not necessarily refer to the same embodiments. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner.

[0411] It should be understood that in the embodiments of the present application, the numbers "first", "second" and the like are merely used to distinguish different objects, such as to distinguish different network devices, and do not limit the scope of the embodiments of the present application, and the embodiments of the present application are not limited thereto.

[0412] It should also be understood that in the present application, "when", "if" and "if" all refer to the case where the network element will make corresponding processing under certain objective conditions, and are not limited by time, and do not require the network element to have a judgment action when implemented, nor does it mean that there are other limitations.

[0413] It should also be understood that in the present application, "at least one" means one or more, and "multiple" means two or more.

[0414] It should also be understood that in the embodiments of the present application, "A corresponding to B" means that B is associated with A and B can be determined according to A. However, it should also be understood that the determination of B according to A does not mean that B is determined only according to A, but B can also be determined according to A and / or other information.

[0415] It should also be understood that the term "and / or" in the present document is merely a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present document generally represents an "or" relationship between the associated objects.

[0416] In the present application, the meaning of the expression similar to "the item includes one or more of the following: A, B, and C" is generally that the item can be any one of the following: A; B; C; A and B; A and C; B and C; A, B and C; A and A; A, A and A; A, A and B; A, A and C, A, B and B; A, C and C; B and B, B, B and B, B, B and C, C and C; C, C and C, and other combinations of A, B and C. The above is an example of three elements A, B and C to illustrate the optional items of the item. When the expression is "the item includes at least one of the following: A, B, …, and X", that is, the expression has more elements, the item can also be applied to the items according to the above rules.

[0417] It can be understood that the terminal device and / or the network device in the embodiments of the present application can perform some or all of the steps in the embodiments of the present application, and these steps or operations are only examples, and the embodiments of the present application can also perform other operations or variations of various operations. In addition, each step can be performed in a different order according to the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application are performed.

[0418] Those skilled in the art can appreciate that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0419] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.

[0420] In the several embodiments provided by the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic. The division of the units is only a logical function division. There can be another division for actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or in other forms.

[0421] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0422] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present alone, or two or more units can be integrated in one unit.

[0423] The functions, if realized in the form of software functional units and sold or used as independent products, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application or the part of the present application that essentially contributes to the prior art or the part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk, and various program code storage media.

[0424] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for multicast communication, characterized in that: include: The first network device sends first information to the second network device, where the first information indicates an association between the multicast service information and the first terminal device; The first network device receives second information from the second network device; The first network device generates a configuration message according to the second information, where the configuration message indicates an association between the multicast service information and a first logical channel, where the first logical channel is a logical channel of the first terminal device; The first network device sends the configuration message to the first terminal device; The first network device has a packet data convergence layer protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function, and the second network device has a radio link control layer function, a media access control layer function, and a physical layer function; The first information indicating an association between the multicast service information and the first terminal device includes: The first information indicates an association relationship between the multicast service information and the first data radio bearer of the first terminal device; as well as, The second information indicates an association relationship between the first data radio bearer and the first logical channel of the first terminal device.

2. The method according to claim 1, wherein The multicast service information includes one or more of the following: a multicast area identifier, a temporary mobile group identifier, a session identifier, and a group wireless network temporary identifier.

3. The method according to claim 1 or 2, wherein: The configuration message is a radio resource control reconfiguration message.

4. The method according to any one of claims 1 or 2, wherein The first network device and the second network device correspond to the same base station.

5. The method according to claim 4, wherein The first network device and the second network device correspond to the same base station.

6. A method for multicast communication, characterized in that: include: The second network device receives first information from the first network device, where the first information indicates an association between the multicast service information and the first terminal device; The second network device sends second information to the first network device, where the second information is used to determine a configuration message, where the configuration message indicates an association between the multicast service information and a first logical channel, where the first logical channel is a logical channel of the first terminal device; The first network device has a packet data convergence layer protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function, and the second network device has a radio link control layer function, a media access control layer function, and a physical layer function; The first information indicating an association between the multicast service information and the first terminal device includes: The first information indicates an association relationship between the multicast service information and the first data radio bearer of the first terminal device; as well as, The second information indicates an association relationship between the first data radio bearer and the first logical channel of the first terminal device.

7. The method according to claim 6, wherein The multicast service information includes one or more of the following: a multicast area identifier, a temporary mobile group identifier, a session identifier, and a group wireless network temporary identifier.

8. The method according to any one of claims 6 or 7, wherein The first network device and the second network device correspond to the same base station.

9. A first network device, characterized in that: include: a transceiver unit, configured to send first information to the second network device, where the first information indicates an association between the multicast service information and the first terminal device; The transceiver unit is further configured to receive second information from the second network device; a processing unit, configured to generate a configuration message according to the second information, the configuration message indicating an association between the multicast service information and a first logical channel, where the first logical channel is a logical channel of the first terminal device; The transceiver unit is further configured to send the configuration message to the first terminal device; The first network device has a packet data convergence layer protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function, and the second network device has a radio link control layer function, a media access control layer function, and a physical layer function; The first information indicating an association between the multicast service information and the first terminal device includes: The first information indicates an association relationship between the multicast service information and the first data radio bearer of the first terminal device; as well as, The second information indicates an association relationship between the first data radio bearer and the first logical channel of the first terminal device.

10. The first network device according to claim 9, wherein: The multicast service information includes one or more of the following: a multicast area identifier, a temporary mobile group identifier, a session identifier, and a group wireless network temporary identifier.

11. The first network device according to claim 9 or 10, characterized in that: The configuration message is a radio resource control reconfiguration message.

12. A second network device, characterized in that: include: a transceiver unit, configured to receive first information from a first network device, wherein the first information indicates an association between multicast service information and a first terminal device; The transceiver unit is further configured to send second information to the first network device, where the second information is used to determine a configuration message, where the configuration message indicates an association between the multicast service information and a first logical channel, where the first logical channel is a logical channel of the first terminal device; The first network device has a packet data convergence layer protocol layer function, a service data adaptation protocol layer function, and a radio resource control layer function, and the second network device has a radio link control layer function, a media access control layer function, and a physical layer function; The first information indicating an association between the multicast service information and the first terminal device includes: The first information indicates an association relationship between the multicast service information and the first data radio bearer of the first terminal device; as well as, The second information indicates an association relationship between the first data radio bearer and the first logical channel of the first terminal device.

13. The second network device according to claim 12, wherein: The multicast service information includes one or more of the following: a multicast area identifier, a temporary mobile group identifier, a session identifier, and a group wireless network temporary identifier.

14. A communication device, characterized in that: The communication device includes a module or a unit for executing the method according to any one of claims 1 to 5.

15. A communication device, characterized in that: The communication device includes a module or unit for executing the method according to any one of claims 6 to 8.

16. A communication device, characterized in that: include: A processor is coupled to a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the apparatus is caused to perform the method according to any one of claims 1 to 8.

17. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is run on a computer, the computer is caused to perform the method according to any one of claims 1 to 8.

18. A computer program product, characterized in that The invention comprises a computer program, which, when running on a computer, causes the computer to perform the method according to any one of claims 1 to 8.

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