Method and related apparatus for transmitting multicast and broadcast service interest indication messages

Abstract

This application provides a method and related apparatus for transmitting a multicast and broadcast service interest indication message, in which a terminal device receives a SIB of an SCell, the SIB including information used to obtain an MCCH configuration of an MBS, and transmits an MII message, the MII message carrying an identifier of an MBS service of interest to the terminal device. Thus, in some embodiments, for example, in a scenario in which a secondary cell can provide a broadcast service, the terminal device may report an identifier of an MBS service of interest to the terminal device based on the received SIB of the SCell, thereby avoiding a problem in which the network side cannot know the MBS broadcast service that the terminal device is interested in receiving.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to Chinese Patent Application No. 202210366678.6, entitled "METHOD FOR TRANSMITTING MULTICAST AND BROADCAST SERVICE INTEREST INDICATION MESSAGE AND RELATED APPARATUS," filed with the State Intellectual Property Office of the People's Republic of China on April 8, 2022, the entire contents of which are incorporated by reference.

[0002] [Technical field] This application relates to the field of communications technology, and more particularly to a method and related apparatus for transmitting multicast and broadcast service interest indication messages. [Background technology]

[0003] A multicast and broadcast service (MBS) is a service targeted at multiple terminal devices and may provide live services, public security services, batch software update services, etc. In MBS, a multicast service is usually a service with high Quality of Service (QoS) requirements, and a broadcast service is usually a service with low QoS requirements. When a broadcast service is provided, a terminal device may autonomously perform reception based on configuration information. For example, configuring a broadcast service requires two steps. One step is for the terminal to receive a system information block (SIB) of a primary cell (PCell) containing information used to obtain a multicast and broadcast service control channel (MBS Control Channel, MCCH) configuration of the MBS, and to receive a SIB of the PCell containing a mapping relationship between a frequency and an MBS or an MBS frequency selective area identifier. The other step is that the terminal needs to report an MBS Interest Indication (MII) message to inform the network side that the terminal device in the radio resource control_connected (RRC_CONNECTED) state is receiving or is interested in receiving the MBS broadcast service.

[0004] It can be seen that whether the terminal device reports the MII message depends on whether the above two SIBs of the PCell are received. However, in a scenario where the secondary cell can provide a broadcast service, how the terminal reports the MII message is an urgent problem to be solved. Summary of the Invention

[0005] This application provides a method and related apparatus for transmitting multicast and broadcast service interest indication messages to obtain more timely multicast and broadcast service interest indication messages.

[0006] According to a first aspect, this application provides a method for transmitting a multicast and broadcast service interest indication message. The method may be performed by a communication device. The communication device may be a communication device or a communication apparatus, such as a chip, that can support the communication device in implementing the functions required in the method. For example, the communication device may be a terminal device, a chip located in the terminal device and configured to implement the functions of the terminal device, or another component configured to implement the functions of the terminal device. In the following description process, an example in which a terminal device is used as an execution entity is used for explanation.

[0007] The method includes: a terminal device receives an SIB of an SCell, the SIB including information used to obtain an MCCH configuration of an MBS, and transmits an MII message, the MII message carrying an identifier of an MBS service of interest to the terminal device. It can be seen that in a scenario where a secondary cell can provide a broadcast service, the terminal device receives an SIB of an SCell including information used to obtain an MCCH configuration of an MBS. In this way, the identifier of the MBS service of interest to the terminal device is reported, thereby avoiding the problem that the network side cannot know the MBS broadcast service that the terminal device is interested in receiving.

[0008] The name of the SIB containing information used to obtain the MCCH configuration of the MBS is not limited in this application. For ease of explanation, the SIB containing information used to obtain the MCCH configuration of the MBS will be referred to as SIB X for short.

[0009] Optionally, the SCell may be an SCell other than a PCell in a serving cell that provides radio resources to the terminal device. Optionally, in a dual connectivity scenario, the SCell is an SCell in a master cell group and / or a secondary cell group that provides radio resources to the terminal device.

[0010] Optionally, the SIB X of the SCell is received through dedicated signaling. Optionally, the MII message may further carry at least one of MBS frequency information and MBS priority information.

[0011] In an optional implementation manner, the terminal device sending an MII message includes: If SIB X of all cells in a cell set has not been received after the last MII message was sent, the terminal device sends an MII message, and the cell set includes one or more cells that provide radio resources to the terminal device. In other words, if the terminal device receives SIB X of an SCell and has not received SIB X of all cells in the cell set after the terminal device last sent an MII message, the terminal device sends an MII message.

[0012] Optionally, the cell set includes one or more cells that provide radio resources to the terminal device after the terminal device last transmitted an MII message. Alternatively, the cell set includes a master cell group and / or a secondary cell group. Alternatively, the cell set includes cells that provide radio resources to the terminal device (i.e., serving cells) and cells that do not provide radio resources to the terminal device (i.e., non-serving cells).

[0013] In another optional implementation manner, the terminal device sending an MII message includes: If the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, the terminal device sends the MII message; In other words, if the terminal device receives SIB X of the SCell and the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, the terminal device sends the MII message.

[0014] By using the above method, the terminal device may autonomously decide whether to report an MII message carrying an identifier of an MBS service based on the SIB X of the received SCell, thereby reporting the MII message in a timely and flexible manner.

[0015] According to a second aspect, the present application further provides a method for transmitting a multicast and broadcast service interest indication message. The method may be performed by a communication device. The communication device may be a communication device or a communication apparatus, such as a chip, that can support the communication device in implementing the functions required in the method. For example, the communication device may be a terminal device, a chip located in the terminal device and configured to implement the functions of the terminal device, or another component configured to implement the functions of the terminal device. In the following description process, an example in which a terminal device is used as an execution entity is used for explanation.

[0016] The method includes: a terminal device receives first indication information, the first indication information instructing the terminal device to report an identifier of a multicast and broadcast service (MBS) service, and sends a multicast and broadcast service interest indication MII message, the MII message carrying the identifier of the MBS service in which the terminal device is interested.

[0017] It can be seen that in this method, the terminal device may determine whether to report an MII message carrying an identifier of an MBS service that the terminal device is interested in based on first indication information from the network device. In this way, the network side can timely know the identifier of the MBS service that the terminal device is interested in, and thereby timely schedule the MBS service for the terminal device. Furthermore, the first indication information is sent by the network device, so that the MII message can be obtained more flexibly.

[0018] In an optional implementation manner, the first indication information is carried in a system message. An indication indicating whether all terminal devices in the cell need to report MII messages may be introduced into the system message. Alternatively, the system message implicitly indicates whether all terminal devices in the cell need to report MII messages.

[0019] In another optional implementation manner, the first indication information is received through dedicated signaling. In this way, the terminal device may determine whether to report an MII message carrying an identifier of the MBS service that the terminal device is interested in based on the dedicated signaling. Therefore, the network side can obtain the MII message in a timely manner.

[0020] In yet another optional implementation manner, the first indication information is carried in a message in the random access procedure. In this way, the terminal device reports the identifier of the MBS service of interest to the terminal device as early as possible in the random access procedure, thereby avoiding a delay caused when the terminal device reports an MII message to the network device after entering a connected mode and performing RRC connection reconfiguration, and avoiding delays and signaling overhead caused by reconfiguration when the resources or scheduling information configured for the MBS service are inappropriate.

[0021] According to a third aspect, this application further provides a method for transmitting a multicast and broadcast service interest indication message. The method may be performed by a communication device. The communication device may be a communication device or a communication apparatus, e.g., a chip, capable of supporting the communication device in implementing the functions required in the method. For example, the communication device is a network device (e.g., a base station), a chip located in the network device and configured to implement the functions of the network device, or another component configured to implement the functions of the network device. The communication method may correspond to the communication method in the second aspect and will be described from the perspective of a network device. An example in which a network device is used as an implementing entity will be used for explanation.

[0022] The method includes: a network device sends first indication information, the first indication information instructing a terminal device to report an identifier of a multicast and broadcast service (MBS) service; the network device receives a multicast and broadcast service interest indication MII message, the MII message carrying the identifier of the MBS service in which the terminal device is interested.

[0023] In this method, it can be seen that the network device indicates whether the terminal device needs to report an MII message carrying an identifier of an MBS service that the terminal device is interested in. In this way, the network side can timely know the identifier of the MBS service that the terminal device is interested in, and thereby timely schedule the MBS service for the terminal device.

[0024] Optionally, the first indication information is carried in a system message. By using the system message, the network device may explicitly or implicitly indicate whether all terminal devices in the cell need to report MII messages carrying identifiers of MBS services.

[0025] Optionally, the first indication information is received through dedicated signaling. In this way, when the network side has MII messages of some terminal devices but does not have MII messages of other terminal devices, the network device can accurately instruct other terminal devices to report MII messages based on dedicated signaling.

[0026] Optionally, the first indication information is carried in a message in the random access procedure. In this way, the network device knows the identifier of the MBS service that the terminal device is interested in during the random access process of the terminal device, thereby avoiding a problem that when the network device knows the identifier of the MBS service that the terminal device is interested in only after the terminal device enters a connected mode and completes the reconfiguration, the resource or scheduling information configured for the MBS service is inappropriate and needs to be reconfigured.

[0027] For further explanation of this part, please refer to the related explanation in the second aspect, and the details will not be described again here.

[0028] According to a fourth aspect, this application provides a communication device. The communication device may be a terminal device, a device within a terminal device, or a device usable in combination with a terminal device. Alternatively, the communication device may be a chip system. The communication device may perform the method of the first or second aspect. The functionality of the communication device may be realized by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions. The units or modules may be software and / or hardware.

[0029] In an optional realization manner, the communication device may include a communication unit and may perform the communication method according to the first aspect. The communication unit may include: configured to receive a system information block (SIB) of a secondary cell (SCell), the SIB including information used to obtain a multicast and broadcast service control channel (MCCH) configuration of a multicast and broadcast service (MBS); The communication device is configured to transmit a multicast and broadcast service interest information MII message, the MII message carrying an identifier of an MBS service of interest to the communication device.

[0030] Optionally, the communication device may further include a processing unit configured to set the content of the MII message or to determine the MII message.

[0031] The communication device may report identifiers of MBS services that are of interest to the communication device, thereby avoiding the problem of the network side not being able to know which MBS broadcast services the communication device is interested in receiving.

[0032] In an optional implementation manner, the communication unit sends an MII message, specifically, if SIB X of all cells in a cell set has not been received since the last time the MII message was sent, the cell set includes one or more cells that provide radio resources to the communication device.

[0033] In another optional implementation manner, the communication unit sends an MII message, specifically, if the identifier of the MBS service of interest to the communication device is different from the identifier of the MBS service carried in the last sent MII message, the communication unit sends the MII message.

[0034] In yet another optional implementation manner, the communication unit sends an MII message, specifically, if SIB X of all cells in the cell set has not been received since the last MII message was sent, and if the identifier of the MBS service of interest to the communication device is different from the identifier of the MBS service carried in the last MII message sent.

[0035] In an optional implementation manner, the SCell is an SCell in a master cell group MCG and / or a secondary cell group SCG that provides radio resources to the communication device.

[0036] In an optional implementation, the cell set includes one or more cells that provide radio resources to the communication device after the communication device last sent an MII message.

[0037] In an optional implementation, the SIB of the SCell is received through dedicated signaling.

[0038] In an optional implementation, the MII information further carries MBS frequency information and MBS priority information.

[0039] In another optional implementation, the communication device includes a communication unit.

[0040] The communication unit is configured to receive first indication information, the first indication information instructing the communication device to report an identifier of a multicast and broadcast service (MBS) service.

[0041] The communication unit is further configured to send a multicast and broadcast service interest indication MII message, where the MII message carries an identifier of an MBS service of interest to the communication device.

[0042] In this manner, the network device knows whether the terminal device needs to report an MII message carrying the identifier of the MBS service that the terminal device is interested in. In this way, the network side can timely obtain the identifier of the MBS service that the terminal device is interested in, and thereby timely schedule the MBS service for the terminal device.

[0043] Optionally, the first indication information is carried in a system message, or the first indication information is received through dedicated signaling, or the first indication information is carried in a message in a random access procedure.

[0044] For the operations performed by the communication device and their beneficial effects, reference is made to the methods and beneficial effects in the first or second aspect.

[0045] According to a fifth aspect, this application provides a communication device. The communication device may be a network device, a device within a network device, or a device usable in combination with a network device. The communication device may perform the method of the first or third aspect. The functionality of the communication device may be realized by hardware, or may be realized by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions. The units or modules may be software and / or hardware.

[0046] In an optional implementation, the apparatus includes a communication unit configured to send first indication information, the first indication information instructing a terminal device to report an identifier of a multicast and broadcast service (MBS) service. The communication unit is further configured to receive a multicast and broadcast service interest indication MII message. The MII message carries the identifier of the MBS service in which the terminal device is interested.

[0047] In optional implementation manners, the first indication information is carried in a system message, or the first indication information is received through dedicated signaling, or the first indication information is carried in a message in a random access procedure.

[0048] For operations performed by the communication device and their beneficial effects, please refer to the method and beneficial effects in the third aspect.

[0049] According to a sixth aspect, the present application provides a computer-readable storage medium for storing instructions, the computer program or instructions being executed by a communication device to implement a method according to any one of the first to third aspects or possible implementations of the first to third aspects.

[0050] According to a seventh aspect, the present application provides a computer program product including instructions that, when read and executed by a communication device, enable the communication device to perform a method as set forth in any one of the first to third aspects or possible implementations of the first to third aspects.

[0051] According to an eighth aspect, the application provides a communication system including at least one communication device configured to perform the method of the second aspect and at least one communication device configured to perform the method of the third aspect. Alternatively, the communication system includes at least one communication device configured to perform the fourth aspect and at least one communication device configured to perform the fifth aspect.

[0052] According to a ninth aspect, the present application provides a circuit. The circuit is coupled to a memory. The circuit is configured to perform a method as set forth in any one of the first to third aspects or possible implementations of the first to third aspects. The circuit may include a chip circuit. [Brief explanation of the drawings]

[0053] [Figure 1]1 is a diagram of a transmission architecture of an MBS according to an embodiment of the present application; [Figure 2] 1 is a diagram of various types of cells according to an embodiment of the present application. [Figure 3] 1 is a schematic flowchart of a method 100 for transmitting an MII message according to an embodiment of the present application. [Figure 4] 2 is a schematic flowchart of a method 200 for transmitting an MII message according to an embodiment of the present application. [Figure 5] 3 is a schematic flowchart of a method 300 for transmitting an MII message according to an embodiment of the present application. [Figure 6] 1 is a diagram of the structure of a communication device according to an embodiment of the present application; [Figure 7] FIG. 10 is a diagram of the structure of another communication device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0054] In the embodiments of this application, a network device may also be referred to as an access network device. An access network device may be a device that provides access to a terminal and may include a radio access network (RAN) device and an access node (AN) device. A RAN device is mainly a wireless network device in a 3GPP network. An AN device may be an access network device not defined by 3GPP. A RAN device is mainly responsible for functions such as radio resource management, quality of service (QoS) management, and data compression and encryption on the air interface side. A RAN device may include various types of base stations, such as macro base stations, micro base stations (also called small cells), relay stations, access points, and balloon-mounted base stations. In systems using different radio access technologies, devices having base station functions may have different names.For example, in a long term evolution (LTE) system, and a fifth generation (5G), sixth generation (6G), or even seventh generation (7G) system, a network device may be a RAN or next-generation Node base station (gNB), an evolved NodeB (eNB or eNodeB), a network device controller (BSC), a network device transceiver station (BTS), a home network device (e.g., a home evolved NodeB or home NodeB, HNB), a baseband unit (BBU), an access point (AP) in a wireless fidelity (Wi-Fi) system, a wireless relay node, a wireless backhaul node, a transmission reception point (TRP), a transmission point (TPP), a wireless hopping node (WTP), a wireless relay node (BBU), a wireless backhaul ... backhaul node (WTP), a wireless relay node (BBU), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a wireless relay node (BBU), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a wireless backhaul node (WTP), a It may also be referred to as an antenna panel (including multiple antenna panels) of one or more groups of network devices in a 5G system, or it may be a network node forming an eNB or a transmission point, for example a baseband unit (BBU), a distributed unit (DU), or a roadside unit (RSU) in a vehicle-to-everything (V2X) scenario or an intelligent driving scenario.

[0055] In some deployments, a gNB or a transmission point may include a central unit (CU), a DU, etc. The gNB or transmission point may further include a radio unit (RU). The CU implements some functions of the gNB or transmission point, and the DU implements some functions of the gNB or transmission point. For example, the CU implements functions of the radio resource control (RRC) layer and the packet data convergence protocol (PDCP) layer, and the DU implements functions of the radio link control (RLC) layer, the media access control (MAC) layer, and the physical (PHY) layer. Information in the RRC layer ultimately becomes information in the physical layer or is converted from information in the physical layer. Therefore, in this architecture, higher layer signaling, such as RRC layer signaling or PDCP layer signaling, may also be considered to be transmitted by the DU or by the DU and RU. It can be understood that the network device may be a CU node, a DU node, or a device including a CU node and a DU node. Optionally, the network device may alternatively be an auxiliary communication device, for example, a satellite.

[0056] In an embodiment of this application, the terminal is a device having a wireless transceiver function, and may be a device located on land (e.g., on a ship), or in the air (e.g., on an aircraft, balloon, or satellite), including an indoor device, an outdoor device, a handheld device, a wearable device, or an in-vehicle device. The terminal may be a mobile phone, a tablet computer (Pad), a computer having a wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal or an in-vehicle terminal device in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical care, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal or a wearable terminal device in a smart home, etc. In some cases, a terminal may also be called a terminal device, user equipment (UE), access terminal device, vehicle-mounted terminal, industrial control terminal, UE unit, UE station, mobile station, remote station, remote terminal device, mobile device, UE agent, UE equipment, etc. A terminal may alternatively be fixed or mobile.

[0057] This application is applicable to communication systems having various radio access technologies (RATs), such as an LTE communication system, a 5G (also called new radio (NR)) communication system, or a transition system between an LTE communication system and a 5G communication system. The transition system may also be called a 4.5G communication system, or obviously, a future communication system, such as a sixth generation (6G) or even a seventh generation (7G) system. The network architectures and service scenarios described in the embodiments of this application are intended to more clearly explain the technical solutions in the embodiments of this application and do not constitute limitations on the technical solutions provided in the embodiments of this application. Those skilled in the art may know that with the evolution of communication network architectures and the emergence of new service scenarios, the technical solutions provided in the embodiments of this application may also be applicable to similar technical problems.

[0058] To clearly describe the technical solutions in the embodiments of this application, terms such as "first" and "second" are used in the embodiments of this application to distinguish between identical or similar items whose functions and effects are basically the same. Those skilled in the art can understand that terms such as "first" and "second" do not limit the number or execution order, and terms such as "first" and "second" do not indicate a clear difference. In the embodiments of this application, terms such as "SIB X1" and "SIB X" are used to distinguish between identical or similar items whose functions and effects are basically the same, but do not limit the names. For example, "SIB x1" may be equivalent to "SIB X1", and "SIB x" may be equivalent to "SIB X". The term "and / or" describes only the association relationship between related objects and indicates that three relationships may exist. For example, A and / or B may represent the following three cases: only A exists, both A and B exist, and only B exists. The character " / " generally indicates an "or" relationship between related objects.

[0059] The following describes some concepts in embodiments of this application.

[0060] 1.MBS Transmission Architecture

[0061] MBS is a service targeted at multiple terminal devices. The transmission architecture of MBS is shown in Figure 1, and includes a data server (e.g., MBS server), a core network device, an access network device (e.g., gNB), and at least one terminal device. The data server transmits MBS data to the core network device. The core network device transmits the MBS data to the access network device. Finally, the access network device transmits the MBS data to at least one terminal device that receives the MBS data.

[0062] As shown in Figure 1, a core network device transmits MBS data to an access network device by using an MBS session, and each MBS session may include at least one MBS QoS flow. The access network device transmits MBS data to a terminal device by using an MBS radio bearer. There are two transmission modes for one MBS radio bearer. As shown in Figure 1, the first transmission mode may be a point-to-multipoint (PTM) transmission mode. The second transmission mode may be a point-to-point (PTP) transmission mode.

[0063] Broadcast services are designed for services with low QoS requirements. All terminal devices in the RRC_CONNECTED state support broadcast services. Core network devices and terminal devices do not need to maintain a group of terminal devices that receive related broadcast services. When a broadcast service is provided, terminal devices may autonomously receive the broadcast service based on configuration information.

[0064] For example, the configuration of a broadcast service requires two steps. One step is that the terminal needs to receive a system information block (SIB) of a primary cell (PCell) containing information used to obtain the multicast and broadcast service control channel (MBS Control Channel, MCCH) configuration of the MBS, and needs to receive an SIB of the PCell containing a mapping relationship between frequencies and MBS or MBS frequency selective area identifiers. The other step is that the terminal needs to report an MBS Interest Indication (MII) message to notify the network side of the MBS broadcast service that the terminal device in a radio resource control_connected (RRC_CONNECTED) state is receiving or is interested in receiving.

[0065] Multicast services are equivalent to multicast services and are designed for services with high QoS requirements. In order for multicast services to provide the same or similar QoS level as unicast services, group management needs to be performed. For multicast services, the core network needs to manage the joining and leaving of terminal devices.

[0066] The method for transmitting MII messages described in this application is applicable to multicast services, broadcast services, etc. Furthermore, multicast service, multicast session, and multicast service are equivalent concepts in this application and may be substituted for each other. Correspondingly, broadcast service, broadcast session, and broadcast service are equivalent concepts in this application and may be substituted for each other.

[0067] 2.SIB X1, SIB X and MII messages

[0068] The names of the SIBs containing information used to obtain the MCCH configuration of an MBS and the names of the SIBs containing the mapping relationship between frequencies and MBSs or MBS frequency selective area identifiers are not limited in this application. For ease of explanation, the SIB containing the mapping relationship between frequencies and MBSs or MBS frequency selective area identifiers is abbreviated as SIB X1, and the SIB containing information used to obtain the MCCH configuration of an MBS is abbreviated as SIB X. X and X1 may be values, for example, X is 20 and X1 is 21. In this case, the SIB containing the mapping relationship between frequencies and MBSs or MBS frequency selective area identifiers is called SIB 21, and the SIB containing information used to obtain the MCCH configuration of an MBS is called SIB 20.

[0069] The MII message includes at least one of the following: (1) MBS frequency information, where the MBS frequency information is MBS frequency information of interest to a terminal device, and the information may be referred to as mbs-FreqList for short. (2) MBS priority information indicating whether the terminal device's MBS reception is prioritized over unicast reception, where the information may be called mbs-Priority for short. (3) Identifiers of MBS services of interest to the terminal device (eg, currently receiving or interested in receiving), where this information is referred to as mbs-ServiceList for short.

[0070] The mbs-ServiceList may be a group of temporary mobile group identities (TMGIs). Therefore, in this application, an MII message carrying identifiers of MBS services of interest to a terminal device may be referred to as an mbs-ServiceList MII message or an MII message carrying a TMGI list.

[0071] By using an MII message, the terminal device may notify the network side of at least one of an identifier of an MBS service of interest to the terminal device in the RRC_CONNECTED state, MBS frequency information, a priority between MBS reception and unicast reception, etc.

[0072] The transmission of the MII message includes three parts. The first part is a trigger mechanism for reporting the MII message, the second part is a decision mechanism for reporting the MII message, and the third part is a setting mechanism for the content of the MII message. When the trigger condition in the first part is met, the terminal device may perform the decision process in the second part to determine whether to send the MII message. Furthermore, when the MII message is sent, the content of the MII message is set according to the setting mechanism in the third part.

[0073] A terminal device that is in RRC_CONNECTED and supports MBS may execute a decision mechanism for MII message reporting when the following trigger mechanism for MII message reporting is met. At least one condition that may be included in the trigger mechanism for MII message reporting is described below. Specifically, the terminal device may execute a related operation of the decision mechanism of the second part when at least one of the following conditions is met: (1) The terminal device successfully establishes an RRC connection. (2) The terminal device enters or leaves a cell that provides broadcast services. (3) Starting or stopping an MBS session (4) The identifier of the MBS service that the terminal device is interested in has changed. (5) A change in priority between MBS broadcast reception and MBS unicast reception by the terminal device; or (6) The terminal device is connected to the PCell that transmits SIB X1.

[0074] When at least one condition in the trigger mechanism of the first part is satisfied, the terminal device may perform a related operation of the decision mechanism of the second part. The process of the decision mechanism of the second part is described below. 1> If SIB X1 of PCell is received, 2> Ensure that the SIB X1 version of the PCell is valid 2> If the terminal device has not sent any MII messages since it was last in the RRC_CONNECTED state, or 2> If the terminal device is connected to a PCell on which SIB X1 has not been transmitted since the last MII message was transmitted, 3> If the MBS frequency information (i.e., mbs-FreqList) of interest to the terminal device is not available, 4> Set the content of the MII message and send the MII message. 2> In other cases, 3> The MBS frequency information (i.e., mbs-FreqList) of interest to the terminal device is different from the MBS frequency information (i.e., mbs-FreqList) included in the last reported MII message, or 3> If the reception priority of the MBS radio bearer and the reception priority of the established unicast bearer have changed since the last time the MII message was sent, 4> Set the MII content and send the MII message 3> Otherwise, if SIB X for PCell is received, 4> If the terminal device is connected to a PCell that has not broadcast SIB X since the terminal device last transmitted an MII message, or 4> If the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, 5> Set the MII contents and send the MII message.

[0075] In the process of the second part of the determination mechanism, the terminal device may determine the content of the MII message based on the third part of the MII message content setting mechanism. The process of the MII message content setting mechanism is described below. 1> Determine that the MBS frequency information (i.e., mbs-FreqList) of interest to the terminal device is not available. 2> Include mbs-FreqList in the MII message, sort mbs-FreqLists in descending order of interest, and include frequency information in mbs-FreqList 2> If the terminal device includes mbs-Priority in the MII message to prioritize receiving all MBS radio bearers instead of preferentially receiving unicast radio bearers and any multicast MRBs, 2> When SIB X of PCell is received, 3> Include mbs-ServiceList in the MII message, and sort the identifiers of the MBS services in mbs-ServiceList in descending order of the interest level of the terminal device.

[0076] It can be seen that whether the content of the MII message includes an identifier of an MBS service of interest to the terminal device is determined by referring to whether SIB X of the PCell is received. In other words, if SIB X of the PCell is received, the reported MII message may include an identifier of an MBS service of interest to the terminal device.

[0077] SIB X of the PCell includes, but is not limited to, the following descriptions: SIB X is SIB X for a multicast service provided by the PCell, SIB X is SIB X for a multicast service provided by the PCell, or SIB X is SIB X provided for a terminal device to receive a multicast service on the PCell.

[0078] Correspondingly, SIB X1 of the PCell includes, but is not limited to, the following descriptions: SIB X1 is SIB X1 for a multicast service provided by the PCell, SIB X is SIB X1 for a multicast service provided by the PCell, or SIB X1 is SIB X1 provided for a terminal device to receive a multicast service on the PCell.

[0079] 3. Cell, serving cell, non-serving cell, primary cell, secondary cell, master cell group and secondary cell group

[0080] A cell is described in terms of resource management or mobility management by a higher layer (e.g., a protocol layer above the physical layer, such as a radio resource control layer or a medium access control layer). The coverage area of ​​an access network device may be divided into one or more cells. One downlink carrier may be configured for one cell. Optionally, at least one uplink carrier may be configured for one cell. Cell is a general term. For a terminal device, a cell that provides radio resources to the terminal device is called a serving cell. Correspondingly, a cell that does not serve the terminal device is called a non-serving cell. For example, a cell that does not provide radio resources to the terminal device or a cell that does not establish a connection to the terminal device is a non-serving cell.

[0081] A PCell in a serving cell is a cell where a terminal device establishes an initial connection, a cell where a radio resource control (RRC) connection re-establishment is performed, or a primary cell designated in a handover process. The PCell is responsible for RRC communication with the terminal device. Other serving cells in the serving cell are called secondary cells. A secondary cell is a serving cell that is added when the terminal device performs RRC reconfiguration and configured to provide additional radio resources to the terminal device.

[0082] Two access network devices connected to a terminal device may be a master access network device and a secondary access network device. Cells covered by each access network device may form one CA group, and the two access network devices may be considered as two CA groups. The CA group covered by the master access network device may be a master cell group (MCG). The MCG may carry the control plane and user plane of the terminal device, may be responsible for transmitting services to the terminal device, and may also be responsible for transmitting control signaling to the terminal device. The CA group covered by the secondary access network device may be called a secondary cell group (SCG). The SCG may carry the user plane of the terminal device and may be responsible for transmitting services to the terminal device. The PCell in the MCG and the SCell in the MCG are combined by using carrier aggregation (CA) technology. The PSCell in the SCG and the SCell in the SCG are also combined by using carrier aggregation technology.

[0083] As shown in Figure 2, cells may be classified into two types, namely, the above-mentioned serving cells and non-serving cells. Furthermore, in DC, serving cells may be further classified into MCG and SCG. As shown in Figure 2, a primary cell in an MCG is called a PCell, other serving cells are called SCells, and a primary cell in an SCG is called a PSCell, other serving cells are called SCells. Optionally, a PCell in an MCG and a PSCell in an SCG may also be called a special cell SpCell.

[0084] According to the above three-part MII message reporting mechanism, it can be seen that whether the MII message reported by the terminal device carries an identifier of an MBS service of interest to the terminal device depends on whether the SIB X of the PCell is received. However, in a scenario where a secondary cell can provide a broadcast service, for example, when only the secondary cell can provide the broadcast service, or when both the PCell and the secondary cell can provide the broadcast service, how the terminal reports the MII message is an urgent problem to be solved.

[0085] This application provides a method 100 for transmitting a multicast and broadcast service interest indication message. In a scenario where a secondary cell may provide a broadcast service, a terminal device may timely transmit an MII message carrying an identifier of an MBS service of interest to the terminal device.

[0086] The following description will be given with reference to the drawings.

[0087] 3 is a schematic flowchart of a method 100 for transmitting an MII message according to the present application. As shown in FIG. 3, the method 100 for transmitting an MII message includes, but is not limited to, the following steps:

[0088] S101. A network device transmits SIB X of an SCell. Correspondingly, a terminal device receives SIB X of the SCell.

[0089] The SCell may be one of the SCells in the MCG and / or secondary cell group SCG that provides radio resources to the terminal device, or one of the SCells other than the PCell in the serving cell that provides radio resources to the terminal device.

[0090] SIB X of an SCell indicates either: SIB X is SIB X for a multicast service provided by the SCell, or SIB X is SIB X provided for a terminal device to receive a multicast service on the SCell, or SIB X is a secondary cell system information block SCellSIB X provided for a terminal device to receive a multicast service on the SCell.

[0091] S102. The terminal device sends an MII message, which carries an identifier of an MBS service that the terminal device is interested in. In response, the network device receives the MII message.

[0092] Optionally, the SIB X of the SCell includes information used to obtain the MCCH configuration of the MBS. The terminal device may receive the MBS service that can be provided by the SCell by using the MCCH configured by using the MCCH configuration. Furthermore, the terminal device may determine an identifier of the MBS service that is of interest to the terminal device based on the MBS service that can be provided by the SCell.

[0093] Optionally, the terminal device sets the content of the MII message based on SIB X of the SCell, and the mbs-ServiceList carried in the MII message is an identifier of an MBS service of interest to the terminal device in the SCell. Alternatively, the mbs-ServiceList carried in the MII message may further include an identifier of an MBS service of interest to the terminal device in the PCell in addition to the identifier of an MBS service of interest to the terminal device in the SCell. Alternatively, the mbs-ServiceList carried in the MII message reported based on SIB X of the SCell is determined by the terminal device, and the mbs-ServiceList carried in the MII message is not limited to an identifier of an MBS service of interest to the terminal device in a particular cell.

[0094] In the method 100 for transmitting an MII message, in a scenario where a secondary cell can provide broadcast services, it can be seen that when SIB X of an SCell is received, an MII message carrying an identifier of an MBS service of interest to the terminal device may also be reported, so as to enable the network side to know the MBS service of interest to the terminal device.

[0095] In an optional implementation manner, when the terminal device receives SIB X of the SCell, a second part may be executed, which executes a mechanism for the terminal device to determine whether to send an MII message. The following describes some optional implementation manners of the mechanism for determining whether to send an MII message by the terminal device.

[0096] Implementation method 1-1: When SIB X of an SCell is received, the terminal device needs to further determine whether to transmit an MII message carrying mbs-ServiceList by referring to whether SIB X of all cells in the cell set has been received since the last MII message was transmitted.

[0097] In other words, if the terminal device receives SIB X for an SCell, and if the terminal device has not received SIB X for all cells in the cell set since the last time it sent an MII message, the terminal device sends an MII message carrying mbs-ServiceList.

[0098] The cell set includes one or more cells that provide radio resources to the terminal device. In some cases, the cell set may be all primary and secondary cells that provide radio resources to the terminal device. In DC, the cell set may be all cells in the MCG and / or SCG. In other cases, the cell set includes cells that provided radio resources to the terminal device before the current time and cells that are currently providing radio resources to the terminal device. In still other cases, the cell set includes one or more cells that provided radio resources to the terminal device after the terminal device last transmitted an MII message. In still other cases, the cell set includes cells that are currently providing radio resources to the terminal device. In the case of at least one of the above cell sets, if SIB X of the SCell has been received and if SIB X of all cells in the cell set has not been received since the last MII message was transmitted, an MII message carrying mbs-ServiceList is transmitted. In other words, if the terminal device has not received SIB X of all cells in the cell set after the last MII message transmission and before receiving SIB X of the current SCell, the terminal device transmits an MII message carrying mbs-ServiceList if SIB X of the current SCell has been received. In this implementation, when the terminal device receives SIB X of the SCell, it can be seen that if the terminal device has not received SIB X of all cells in the cell set after the last MII message transmission, the terminal device may report an MII message carrying mbs-ServiceList.

[0099] For example, the cell set includes cell 1 and cell 2, which provided radio resources to the terminal device before the current time, and cell 3, which currently provides radio resources to the terminal device. At time T1, when the terminal device is located in cell 1, cell 1 provides SIB X. Therefore, the terminal device may report an MII message carrying mbs-ServiceList. At time T2, the terminal device moves from cell 1 to cell 2, and cell 2 does not provide SIB X. At time T3, the terminal device moves from cell 2 to cell 3, and cell 3 provides SIB X. Cells 1 to 3 are respectively covered by three different access network devices. After the terminal device reported an MII message carrying mbs-ServiceList at time T1 and before time T3, neither cell 2 nor cell 3 provides SIB X. Therefore, cell 3 provides SIB X at time T3. The terminal device may again report an MII message carrying mbs-ServiceList. In this way, when the terminal device moves from cell 1 to cell 2, the access network device in cell 1 may forward to cell 2 an MII message carrying the mbs-ServiceList and reported by the terminal device. However, because cell 2 does not provide SIB X, and therefore presumably cannot support MBS, when the terminal device moves to cell 3, the MII message carrying the mbs-ServiceList is not forwarded to the network device in cell 3 because the terminal device does not recognize the MII message. In other words, when the terminal device moves from cell 2 to cell 3, the RRC configuration forwarded by the access network device in cell 2 to the access network device in cell 3 does not include the mbs-ServiceList. However, if cell 3 supports MBS, when the terminal device receives SIB X from cell 3, the terminal device may timely report an MII message carrying the mbs-ServiceList, thereby notifying the network side of the identifiers of the services in which the terminal device is interested, thereby enabling the network side to timely and accurately schedule MBS services to the terminal device.

[0100] In another example, the cell set includes cell 1, and the terminal device is located in cell 1 before the current time. At time T1, cell 1 provides SIB X1 but does not provide SIB x. Therefore, the terminal device may report an MII message that does not carry mbs-ServiceList. At time T2, cell 1 starts to provide SIB X. Before time T2 and after the terminal device reports the MII message that does not carry mbs-ServiceList, cell 1 does not provide SIB X. Therefore, at time T2, cell 1 provides SIB X, and the terminal device may timely report an MII message that carries mbs-ServiceList, thereby notifying the network side of identifiers of services that the terminal device is interested in, so that the network side can timely schedule MBS services for the terminal device.

[0101] Implementation method 1-2: When SIB X of SCell is received, the terminal device needs to further determine whether to send an MII message carrying mbs-ServiceList by referring to whether the identifier of the MBS service that the terminal device is interested in has changed.

[0102] In other words, when a terminal device receives SIB X of an SCell, and the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, the terminal device transmits an MII message carrying the mbs-ServiceList.

[0103] Implementation method 1-3: When SIB X of an SCell is received, the terminal device needs to further determine whether to send an MII message carrying an mbs-ServiceList by referring to whether SIB X of all cells in the cell set has been received since the last time the MII message was sent and whether the identifiers of the MBS services of interest to the terminal device have changed.

[0104] In other words, if the terminal device receives SIB X of an SCell, if the terminal device has not received SIB X of all cells in the cell set since the last time it transmitted an MII message, and if the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, the terminal device shall transmit an MII message carrying mbs-ServiceList.

[0105] This application provides a method 200 for transmitting a multicast and broadcast service interest indication message. In a scenario where both a primary cell and a secondary cell may provide broadcast services, a terminal device may timely transmit an MII message carrying an identifier of an MBS service of interest to the terminal device.

[0106] 4 is a schematic flowchart of a method 200 for transmitting an MII message according to the present application. As shown in FIG. 4, the method 200 for transmitting an MII message includes, but is not limited to, the following steps:

[0107] S101. A network device transmits a SIB X of a primary cell or a secondary cell. Correspondingly, a terminal device receives a SIB X of the primary cell or the secondary cell.

[0108] The primary cell is a PCell, and the secondary cell is an SCell other than a PCell. In a DC, the primary cell may be a PCell in an MCG and / or a PSCell in an SCG, and the secondary cell may be an SCell in an MCG and / or a SCell in an SCG.

[0109] SIB X of a primary cell or a secondary cell indicates: SIB X is SIB X for a multicast service provided by the primary cell or the secondary cell, or SIB X is SIB X for a multicast service provided by the primary cell or the secondary cell, or SIB X is SIB X provided for a terminal device to receive a multicast service in the primary cell or the secondary cell.

[0110] S202. The terminal device sends an MII message carrying an identifier of an MBS service of interest to the terminal device.

[0111] Optionally, the SIB X of the primary cell or the secondary cell includes information used to obtain the MCCH configuration of the MBS. The terminal device may receive the MBS service that can be provided by the SCell by using the MCCH configured by using the MCCH configuration. Furthermore, the terminal device may determine an identifier of the MBS service that is of interest to the terminal device based on the MBS service that can be provided by the primary cell or the secondary cell.

[0112] Optionally, the terminal device sets the content of the MII message based on the SIB X of the primary cell or the secondary cell, and the mbs-ServiceList carried in the MII message is an identifier of an MBS service of interest to the terminal device in the primary cell or the secondary cell. Alternatively, the mbs-ServiceList carried in the MII message includes identifiers of MBS services of interest to the terminal device in the primary cell and the secondary cell. Alternatively, the mbs-ServiceList carried in the MII message is a union or intersection of identifier sets of MBS services of interest to the terminal device in the primary cell and the secondary cell.

[0113] Optionally, when a terminal device receives SIB X of a secondary cell and reports an MII message carrying an identifier of an MBS service of interest to the terminal device, the identifier of the MBS service carried in the MII message is the identifier of the MBS service of interest to the terminal device in the secondary cell. When a terminal device receives SIB X of a primary cell and reports an MII message carrying an identifier of an MBS service of interest to the terminal device, the identifier of the MBS service carried in the MII message is the identifier of the MBS service of interest to the terminal device in the primary cell. When a terminal device receives SIB X of the primary cell and the secondary cell and reports an MII message carrying an identifier of an MBS service of interest to the terminal device, the identifier of the MBS service carried in the MII message is the identifier of the MBS service corresponding to the mbs-ServiceList of the primary cell and the mbs-ServiceList of the secondary cell, respectively. In other words, the MII message carries the mbs-ServiceList of the primary cell and the mbs-ServiceList of the secondary cell.

[0114] When the MII message carries the mbs-ServiceList of the primary cell and the mbs-ServiceList of the secondary cell, compared with the case where the MII message carries one mbs-ServiceList, one mbs-ServiceList may be added to the MII message. Optionally, the original mbs-ServiceList may be used as the mbs-ServiceList of the primary cell, and the added mbs-ServiceList may be used as the mbs-ServiceList of the secondary cell. Optionally, the mbs-ServiceList of the secondary cell may be implicitly or explicitly carried in the MII message.

[0115] In other words, in the method 200 for transmitting an MII message, regardless of whether the terminal device receives SIB X of the primary cell or the secondary cell, the terminal device may transmit an MII message carrying an identifier of an MBS service of interest to the terminal device, thereby enabling the terminal device to timely transmit an MII message carrying an identifier of an MBS service of interest to the terminal device in a scenario where both the primary cell and the secondary cell may provide broadcast services.

[0116] Optionally, when the terminal device receives SIB X of the primary cell or the secondary cell, the terminal device may implement a mechanism for determining whether to send an MII message carrying the mbs-ServiceList. Some optional implementations of the mechanism for determining whether to send an MII message carrying the mbs-ServiceList are described below.

[0117] Implementation method 2-1: When SIB X of a primary cell or a secondary cell is received, the terminal device needs to further determine whether to transmit an MII message carrying mbs-ServiceList by referring to whether SIB X of all cells in the cell set has been received since the last time the MII message was transmitted.

[0118] In other words, when the terminal device receives SIB X of the primary cell or secondary cell, and has not received SIB X of all cells in the cell set since the terminal device last transmitted an MII message, the terminal device transmits an MII message carrying mbs-ServiceList. Specifically, when the terminal device has not received SIB X of all cells in the cell set since the terminal device last transmitted an MII message and before receiving SIB X of the currently primary cell or secondary cell, the terminal device transmits an MII message carrying mbs-ServiceList if SIB X of the currently primary cell or secondary cell is received. In this implementation, it can be seen that when the terminal device receives SIB X of the primary cell or secondary cell, if the terminal device has not received SIB X of all cells in the cell set since the terminal device last transmitted an MII message, the terminal device may report an MII message carrying mbs-ServiceList.

[0119] For the relevant description of the cell set, please refer to the relevant description in the above implementation method 1-1, and the details will not be described again here.

[0120] For example, the cell set includes cell 1-1 (primary cell) and cell 1-2 (secondary cell) that are covered by network device 1 and provide radio resources to the terminal device at time T1, cell 2 (primary cell) that is covered by network device 2 and provides radio resources to the terminal device at time T2, and cell 3-1 (primary cell) and cell 3-2 (secondary cell) that are covered by network device 3 and currently provide radio resources to the terminal device. At time T1, the terminal device is located in cells 1-1 and 1-2 served by network device 1. If cell 1-1 or cell 1-2 provides SIB X, the terminal device may report an MII message carrying mbs-ServiceList. At time T2, the terminal device is handed over from network device 1 to network device 2, and cell 2 does not provide SIB X. At time T3, the terminal device is handed over from network device 2 to network device 3, and cell 3-1 does not provide SIB X, and cell 3-2 provides SIB X. After the terminal device reports the MII message at time T1 and before time T3, none of cell 2, cell 3-1, and cell 3-2 provides SIB X. Therefore, cell 3-2 provides SIB X at time T3, and the terminal device may report an MII message carrying mbs-ServiceList. In this way, when the terminal device is handed over from network device 1 to network device 2, network device 1 may forward the MII message carrying mbs-ServiceList and reported by the terminal device to network device 2. However, because cell 2 does not provide SIB X, network device 2 cannot identify the MII message, presumably because cell 2 does not support MBS. When the terminal device is handed over to network device 3, network device 2 does not identify the MII message, and therefore does not forward the MII message carrying mbs-ServiceList to network device 3.In other words, when the terminal device is handed over from network device 2 to network device 3, the RRC configuration transferred by network device 2 to network device 3 does not include mbs-ServiceList. However, if cell 3-2 supports MBS, when the terminal device can receive SIB X of cell 3-2, the terminal device may timely report an MII message carrying mbs-ServiceList, thereby notifying the network side of the identifiers of services that the terminal device is interested in, so as to enable the network side to timely schedule MBS services to the terminal device.

[0121] In another example, the cell set includes cell 1-1 (primary cell) and cell 1-2 (secondary cell), and the terminal device is located in cell 1-1 before the current time. At time T1, cell 1-1 or cell 1-2 provides SIB X1 but does not provide SIB x. Therefore, the terminal device may report an MII message that does not carry mbs-ServiceList. At time T2, cell 1-1 or cell 1-2 provides SIB X. Before time T2 and after the terminal device reports the MII message that does not carry mbs-ServiceList, neither cell 1-1 nor cell 1-2 provides SIB X. Therefore, at time T2, cell 1-1 or cell 1-2 provides SIB X, and the terminal device may timely report an MII message that carries mbs-ServiceList, thereby notifying the network side of identifiers of services that the terminal device is interested in, thereby enabling the network side to timely schedule MBS services for the terminal device.

[0122] Implementation method 2-2: When SIB X of a primary cell or a secondary cell is received, the terminal device needs to further determine whether to send an MII message carrying the mbs-ServiceList by referring to whether the identifier of the MBS service of interest to the terminal device has changed.

[0123] In other words, if the terminal device receives SIB X of a primary cell or a secondary cell, and if the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, the terminal device transmits an MII message carrying mbs-ServiceList.

[0124] Implementation method 2-3: When SIB X of a primary cell or a secondary cell is received, the terminal device must further determine whether to send an MII message carrying the mbs-ServiceList by referring to whether SIB X of all cells in the cell set has been received since the last time the MII message was sent and whether the identifiers of the MBS services of interest to the terminal device have changed.

[0125] In other words, if the terminal device receives SIB X of a primary cell or a secondary cell, if the terminal device has not received SIB X of all cells in the cell set since the last time it transmitted an MII message, and if the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, the terminal device transmits an MII message carrying mbs-ServiceList.

[0126] Based on the mechanism in the method for transmitting an MII message, in which the terminal device can decide whether to send an MII message when it receives SIB X of a primary cell or a secondary cell, the mechanisms in the above first to third parts are appropriately modified.

[0127] In the first part, the trigger mechanism for MII message reporting is as follows: In this mechanism, in addition to at least one of the above conditions (1) to (6) which can enable the terminal device to perform the decision mechanism for MII message reporting described in the second part, the mechanism may further include a condition (7) that the terminal device receives SIB X of the primary cell and / or the secondary cell.

[0128] Optionally, condition (7) may be that the terminal device is connected to the primary cell and / or secondary cell from which SIB X is transmitted, or that the terminal device receives SIB X of the primary cell and / or secondary cell for the first time.

[0129] In the second part, in the mechanism for determining whether to send an MII message, the process of determining whether to send an MII message carrying an identifier of an MBS service may include, but is not limited to, the following steps: If SIB X for PCell or SCell is received, and If SIB X of all cells in the cell set has not been received since the terminal device last transmitted an MII message, or if the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, The content of the MII is set and an MII message is sent, and the MII message carries the identifier of the MBS service.

[0130] Optionally, the mechanism in the second part for determining whether to report an MII message by the terminal device may include, but is not limited to, the following process: 1> When SIB X1 of PCell or SCell is received, 2> Ensure that the SIB X1 version of the PCell or SCell is valid 2> If the terminal device has not sent any MII messages since it was last in the RRC_CONNECTED state, or 2> If the terminal device is connected to a PCell on which SIB X1 has not been transmitted since the last MII message was transmitted, 3> If the MBS frequency information (i.e., mbs-FreqList) of interest to the terminal device is not available, 4> Set the content of the MII message and send the MII message. 2> In other cases, 3> The MBS frequency information (i.e., mbs-FreqList) of interest to the terminal device is different from the MBS frequency information (i.e., mbs-FreqList) included in the last reported MII message, or 3> If the reception priority of the MBS radio bearer and the reception priority of the established unicast bearer have changed since the last time the MII message was sent, 4> Set the MII content and send the MII message 3> Otherwise, if SIB X of PCell or SCell is received, 4> If the terminal device has not received SIB X of all cells in the cell set since the terminal device last sent an MII message, or 4> If the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, 5> Set the MII contents and send the MII message.

[0131] Optionally, in the second part, the process steps in the mechanism for determining whether to transmit an MII message may alternatively be performed separately as several steps. For example, the process steps in the mechanism for determining whether to transmit an MII message may only include: setting the content of the MII and transmitting an MII message, where the MII message carries an identifier of an MBS service, if SIB X of a PCell or SCell is received and if SIB X of all cells in a cell set has not been received since the terminal device last transmitted an MII message. The combination manner of the process steps in the mechanism for determining whether to transmit an MII message in the second part is not limited in this application.

[0132] It should be noted that in the mechanism for determining whether to report an MII message in the second part, whether the transmitted MII message carries identifiers of MBS services of interest to the terminal device (i.e., mbs-ServiceList) is determined by referring to whether SIB X of the PCell or SCell is received. Specifically, if SIB X of the PCell or SCell is received, the transmitted MII message carries identifiers of MBS services of interest to the terminal device (i.e., mbs-ServiceList). If SIB X of the PCell or SCell is not received, the transmitted MII message does not carry identifiers of MBS services of interest to the terminal device (i.e., mbs-ServiceList).

[0133] In the third part, the mechanism for setting the content of the MII by the terminal device is as follows: 1> Determine that the MBS frequency information (i.e., mbs-FreqList) of interest to the terminal device is not available. 2> Include mbs-FreqList in the MII message, sort mbs-FreqLists in descending order of interest, and include frequency information in mbs-FreqList 2> If the terminal device includes mbs-Priority in the MII message to prioritize receiving all MBS radio bearers instead of prioritized receiving the unicast radio bearer and any MBS radio bearer, 2> When SIB X of PCell or SCell is received, 3> Include mbs-ServiceList in the MII message, and sort the identifiers of the MBS services in mbs-ServiceList in descending order of the interest level of the terminal device.

[0134] Optionally, the mbs-ServiceList carried in the MII message is an identifier of an MBS service of interest to the terminal device in the primary cell or the secondary cell. Alternatively, the mbs-ServiceList carried in the MII message includes an identifier of an MBS service of interest to the terminal device in the primary cell and the secondary cell. Alternatively, the mbs-ServiceList carried in the MII message is a union or intersection of the identifier sets of MBS services of interest to the terminal device in the primary cell and the secondary cell.

[0135] Optionally, when a terminal device receives SIB X of a secondary cell and reports an MII message carrying an identifier of an MBS service of interest to the terminal device, the identifier of the MBS service carried in the MII message is the identifier of the MBS service of interest to the terminal device in the secondary cell. When a terminal device receives SIB X of a primary cell and reports an MII message carrying an identifier of an MBS service of interest to the terminal device, the identifier of the MBS service carried in the MII message is the identifier of the MBS service of interest to the terminal device in the primary cell. When a terminal device receives SIB X of the primary cell and the secondary cell and reports an MII message carrying an identifier of an MBS service of interest to the terminal device, the identifier of the MBS service carried in the MII message is the identifier of the MBS service corresponding to the mbs-ServiceList of the primary cell and the mbs-ServiceList of the secondary cell, respectively. In other words, the MII message carries the mbs-ServiceList of the primary cell and the mbs-ServiceList of the secondary cell.

[0136] When the MII message carries the mbs-ServiceList of the primary cell and the mbs-ServiceList of the secondary cell, compared with the case where the MII message carries one mbs-ServiceList, one mbs-ServiceList may be added to the MII message. Optionally, the original mbs-ServiceList may be used as the mbs-ServiceList of the primary cell, and the added mbs-ServiceList may be used as the mbs-ServiceList of the secondary cell. Optionally, the mbs-ServiceList of the secondary cell may be implicitly or explicitly carried in the MII message.

[0137] For example, assume that after the terminal device enters the RRC_CONNECTED state:

[0138] At time T1, if the terminal device satisfies at least one of conditions (1) to (7) in the first part and the terminal device receives SIB X1 of the primary cell or secondary cell, the terminal device executes the process of the mechanism described in steps 1> to 5> in the second part to determine whether the terminal device reports an MII message. Furthermore, after step 1> is satisfied, step 2>: if the terminal device has not transmitted an MII message since the last time it was in the RRC_CONNECTED state is executed. Therefore, the terminal device may execute step 4>: setting the content of the MII message and transmitting the MII message. Refer to the mechanism for setting the content of the MII message described in the third part for setting the content of the MII message by the terminal device. Since SIB X1 of the primary cell or secondary cell is received at time T1 and SIB X is not received, the setting content of the MII message includes mbs-FreqList and mbs-Priority but does not include mbs-ServiceList. Furthermore, the terminal device sends an MII message carrying mbs-FreqList and mbs-Priority.

[0139] At time T2, if the terminal device satisfies at least one of conditions (1) to (7) in the first part and receives SIB X of the primary cell or secondary cell, the terminal device executes the process of the mechanism described in steps 1> to 5> in the second part to determine whether the terminal device reports an MII message. Furthermore, after step 1> is satisfied, the conditions of steps 2> and 3> otherwise are not satisfied, so step 3> is executed. Otherwise, SIB X of the PCell or SCell is received, and step 4>: if the terminal device has not received SIB X of all cells in the cell set since the terminal device last transmitted an MII message, the terminal device may execute step 5>: configure the content of the MII message and transmit the MII message. Refer to the mechanism for configuring the content of the MII message described in the third part for configuring the content of the MII message by the terminal device. Since SIB X of the primary cell or secondary cell is received at time T2, the configuration content of the MII message includes mbs-FreqList, mbs-Priority, and mbs-ServiceList. Furthermore, the terminal device sends an MII message carrying mbs-FreqList, mbs-Priority and mbs-ServiceList.

[0140] Optionally, the terminal device receiving the SIB X1 of the primary cell or the secondary cell at time T1 may satisfy condition (6) in the first part, so that the terminal device performs the process of the mechanism described in steps 1> to 5> in the second part to decide whether to report the MII message.

[0141] Optionally, the terminal device receiving the SIB X of the primary cell or the secondary cell at time T2 may satisfy condition (7) in the first part, so that the terminal device performs the process of the mechanism described in steps 1> to 5> in the second part to decide whether to report the MII message.

[0142] In another example, after the terminal device enters the RRC_CONNECTED state, assume the following:

[0143] At time T1, if the terminal device satisfies at least one of conditions (1) to (7) in the first part and receives SIB X1 and SIB X of the primary or secondary cell, the terminal device executes the process of the mechanism described in steps 1> to 5> in the second part to determine whether the terminal device reports an MII message. Furthermore, after step 1> is satisfied, step 2>: If the terminal device has not transmitted an MII message since the last time it was in the RRC_CONNECTED state is executed, and the terminal device may execute step 4>: Set the content of the MII message and transmit the MII message. Refer to the mechanism for setting the content of the MII message described in the third part for setting the content of the MII message by the terminal device. Since SIB X1 of the primary or secondary cell and SIB X have also been received at time T1, the set content of the MII message includes mbs-FreqList, mbs-Priority, and mbs-ServiceList. Furthermore, the terminal device sends an MII message carrying mbs-FreqList, mbs-Priority and mbs-ServiceList.

[0144] At time T2, if the terminal device satisfies at least one of the conditions (1) to (7) in the first part and the terminal device can still receive the SIB X1 and SIB X of the primary cell or the secondary cell, the terminal device executes the process of the mechanism described in steps 1> to 5> in the second part, which determines whether the terminal device reports an MII message. <1> After the condition is met, the conditions of step 2 and other steps are not met, so the steps of setting the content of the MII message and sending the MII message cannot be performed. Therefore, the terminal device no longer sends the MII message.

[0145] Optionally, the terminal device receiving SIB X1 and SIB X of the primary cell or the secondary cell at time T1 may satisfy condition (7) in the first part, so that the terminal device performs the process of the mechanism described in steps 1> to 5> in the second part to decide whether to report the MII message.

[0146] Optionally, the terminal device receiving SIB X1 and SIB X of the primary cell or the secondary cell at time T2 may satisfy condition (7) in the first part, so that the terminal device performs the process of the mechanism described in steps 1> to 5> in the second part to decide whether to report the MII message.

[0147] The following describes possible implementations of the process of determining whether to send an MII message carrying an identifier of an MBS service based on different representations of a primary cell or a secondary cell.

[0148] Implementation method 3-1: If SIB x is received for the PCell or SCell (else if SIB x is provided by the PCell or SCell), If SIB x for the PCell and all available SCells has not been received since the last time the MII message was transmitted (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to a PCell not broadcasting SIB x and all SCells (if available) also not provided SIB x), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0149] The determined identifier of the MBS service of interest to the terminal device may be determined based on a mechanism for setting a service list, and setting the content of the MII message may be determined based on a mechanism for setting the content of the MII.

[0150] Implementation method 3-2 is described for MCG. If SIB x is provided by one cell of the MCG, If SIB x has not been received from all cells in the MCG since the last time the MII message was sent (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cells of MCG not broadcasting SIB x), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0151] Implementation method 3-3 is described for MCG. If SIB X of the PCell or SIB X of the SCell in the MCG is received (else if SIB x is provided by the PCell or SCell of MCG), If SIB X of the PCell and SIB X of all SCells in the MCG have not been received since the last time the MII message was transmitted (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to a PCell and all cells of SCells in MCG not broadcasting SIB x), or 4> If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0152] Implementation method 3-4: If SIB x is received by the serving cell(s), then If SIB x of all serving cells has not been received since the last time the MII message was transmitted (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell of serving cell(s) not broadcasting SIB x), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0153] Implementation method 3-5: else if SIBx is provided by at least one cell of serving cell(s), If SIB x of all serving cells has not been received since the last time the MII message was transmitted (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell of serving cell(s) not broadcasting SIB x), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0154] Implementation methods 3-6 are described for MCG. If SIB x is received from MCG (else if SIBx is provided by MCG), If SIB x has not been received from any cell in the MCG since the last time the MII message was sent (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cells of MCG not broadcasting SIB x), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0155] Implementation methods 3-7 are described for MCG. If SIB x is provided by at least one cell of MCG, If SIB X has not been received from any cell in the MCG since the last time the MII message was sent (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cells of MCG not broadcasting SIB X), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0156] Implementation methods 3-8 are described for MCG. If SIB X is received for the PCell or SCell in MCG (else if SIB X is provided for the PCell or SCell of MCG), If SIB X has not been received from any cell in the MCG since the last time the MII message was sent (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cells of MCG not broadcasting SIB X), or If the determined identifiers of the MBS services of interest to the terminal device are different from the identifiers of the MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined in accordance with 5.x.4.4 is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication according to 5.x.4.5 and initiate the transmission of MBSInterestIndication message).

[0157] Implementation method 3-9: If SIB X for the PCell or ScellSIB X for the SCell is received (else if SIBx is provided for the PCell, or ScellSIBx is provided for the SCell), If SIB X of the PCell and Scell ​​SIB X of the SCell have not been received since the last time the MII message was transmitted (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to the PCell not broadcasting SIB X and the SCell not broadcasting Scell ​​SIB X), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), 5> Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication according to 5.x.4.5 and initiate the transmission of the MBSInterestIndication message).

[0158] Implementation method 3-10 is described for MCG. 3> If SIB X of the PCell in the MCG or ScellSIB X of the SCell is received (else if SIBx is provided for the PCell, or ScellSIBx is provided for the SCell of MCG), If SIB X of the PCell and Scell ​​SIB X of the SCell have not been received since the last time the MII message was transmitted (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to the PCell not broadcasting SIB X and all SCells in MCG not broadcasting Scell ​​SIB X), or 4> If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0159] Implementation Method 3-11: If SIBx or ScellSIBx is provided by serving cell(s), If SIB X and / or ScellSIB X of all serving cells have not been received since the last time the MII message was transmitted (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all serving cell(s) not broadcasting SIB X and / or ScellSIB X), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0160] Implementation method 3-12: If at least one SIB X or ScellSIB X is received from the serving cell (else if SIBx or ScellSIBx is provided by at least one cell), If SIB X or Scell ​​SIB X of all serving cells has not been received since the last time the MII message was transmitted (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all of cell(s) not broadcasting SIB X and Scell ​​SIB X), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0161] Implementation method 3-13 is described for MCG. If SIBx or SCellSIBx is provided by at least one cell of MCG, then: If SIB X and ScellSIBx of all cells in the MCG have not been received since the last time the MII message was sent (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cells of MCG not broadcasting SIB X and ScellSIBx), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0162] Implementation method 3-14 is described for MCG. If SIBx or SCellSIBx is provided by MCG, If SIBx and ScellSIBx of all cells in the MCG have not been received since the last time the MII message was sent (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cells of MCG not broadcasting SIBx and / or ScellSIBx), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0163] Implementation Method 3-15: If SIB X or SCellSIB X is received (else if SIBx or SCellSIBx is provided), If SIB x and ScellSIBx of all cells in the MCG have not been received since the last time the MII message was sent (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell not broadcasting SIBx and ScellSIBx), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0164] Implementations 3 to 15 do not limit the serving cell or non-serving cell from which the terminal device receives SIB X or SCellSIB X. Specifically, the terminal device may receive SIB X or SCellSIB X through a serving cell, or may receive SIB X or SCellSIB X through a non-serving cell.

[0165] This application provides a method 300 for transmitting multicast and broadcast service interest indication messages, thereby enabling a terminal device to timely send MII messages carrying identifiers of MBS services of interest to the terminal device.

[0166] 5 is a schematic flowchart of a method 300 for transmitting an MII message according to the present application. As shown in FIG. 5, the method 300 for transmitting an MII message includes, but is not limited to, the following steps:

[0167] S301. A network device transmits first instruction information. Correspondingly, a terminal device receives the first instruction information. The first instruction information instructs a communication device to report an identifier of a multicast and broadcast service (MBS).

[0168] Optionally, the first indication information instructs the terminal device to report an MII message carrying an identifier of an MBS service of interest to the terminal device.

[0169] S302. The terminal device transmits an MII message carrying an identifier of an MBS service of interest to the terminal device. In response, the network device receives the MII message. It can be seen that in the method 300 for transmitting an MII message, the network device explicitly indicates that the terminal device needs to report an MII message carrying an identifier of an MBS service of interest to the terminal device. If the network device requests the terminal device to report an MII message carrying an identifier of an MBS service of interest to the terminal device, the network device transmits first indication information. If the network device does not request the terminal device to report an MII message carrying an identifier of an MBS service of interest to the terminal device, the network device transmits indication information indicating that the terminal device does not need to report the identifier of the MBS service, or if the terminal device does not receive the first indication information, it is considered or specified by default that the terminal device will not report an MII message carrying an identifier of an MBS service of interest to the terminal device.

[0170] In an optional implementation manner, the first indication information is carried in a system message. For example, an indication indicating whether all UEs in the cell need to report MII messages is introduced into the system message. In this way, when the network does not have MII messages forwarded by other network devices, the network sends an indication indicating that all UEs in the cell need to report MII messages. In another example, some information element (IE) or field in the system message may be used for implicit indication to indicate whether an MII message needs to be reported, or the first indication information is configured to be reported periodically. In this way, when accessing a cell, the terminal device does not need to make a decision by itself, but can know whether an MII message needs to be reported or whether an MII message including the mbs-FreqList needs to be reported by reading the system message sent by the network device.

[0171] In another optional implementation manner, the first indication information is received through dedicated signaling. In this way, when the network side has MII messages of some terminal devices but not MII messages of other terminal devices, the network device may accurately instruct other terminal devices to report MII messages based on the dedicated signaling. In this way, when accessing a cell, the terminal device does not need to make a decision by itself, but can know whether an MII message needs to be reported or whether an MII message including the mbs-FreqList needs to be reported by reading the dedicated signaling sent by the network device. When the network device has the MII messages of the terminal devices, the network device does not need to instruct the terminal devices to report MII messages. The first indication information may be implicitly or explicitly indicated by using some IEs or fields in the dedicated signaling.

[0172] Based on the mechanism in the method 300 for transmitting an MII message, in which the first indication information may trigger the terminal device to determine whether to send an MII message, the mechanisms in the above first to third parts are appropriately modified.

[0173] In the first part, the trigger mechanism for MII message reporting is as follows: In this mechanism, in addition to at least one of the above conditions (1) to (6) that can enable the terminal device to execute the decision mechanism for MII message reporting described in the second part, the mechanism may further include a condition (7) that the terminal device receives SIB X of the primary cell or the secondary cell, and / or a condition (8) that the terminal device receives first indication information.

[0174] Optionally, condition (7) may be that the terminal device is connected to the primary cell and / or secondary cell from which SIB X is transmitted, or that the terminal device receives SIB X of the primary cell and / or secondary cell for the first time.

[0175] In the second part, the mechanism for determining whether to send an MII message is as follows.

[0176] In an optional implementation manner, the process of determining whether to send an MII message carrying an identifier of an MBS service may include: First indication information is received, where the first indication information instructs the terminal device to report an identifier of a multicast and broadcast service (MBS) service (else if MII-ind is provided), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0177] MII-ind represents the first indication information.

[0178] In another optional implementation manner, the process of determining whether to send an MII message carrying an identifier of an MBS service may include: First indication information is received, where the first indication information instructs the terminal device to report an identifier of a multicast broadcast service (MBS) service (else if MII-ind is provided), and If the MCG does not send (or indicate) the first indication information after the last time the MII message was sent (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to the MCG not indicating MII-ind), or If the determined identifiers of MBS services of interest to the terminal device are different from the identifiers of MBS services carried in the last transmitted MII message (if the set of MBS broadcast services of interest determined is different from the mbs-ServiceList included in the last transmission of the MBS Interest Indication), Set the contents of the MII message and trigger the transmission of the MII message (set the contents of MBS Interest Indication and initiate the transmission of MBSInterestIndication message).

[0179] Correspondingly, in the third part, the mechanism for setting the content of the MII message by the terminal device is as follows: If the first indication information is received (if MII-ind is scheduled), The MII message includes the determined mbs-ServiceList, and the identifiers of the MBS services in the mbs-ServiceList are sorted in decreasing order of interest to the terminal device (include mbs-ServiceList and set it to indicate the set of MBS services of interest sorted by decreasing order of interest determined).

[0180] MII-ind represents the first indication information.

[0181] This application further provides a method 400 for transmitting an MII message. In the method 400 for transmitting an MII message, the method 100 for transmitting an MII message may be combined with the method 400 for transmitting an MII message. Specifically, when SIB X of an SCell is received, whether or not to transmit an MII message carrying an mbs-ServiceList is determined by referring to whether first indication information is received.

[0182] For example, when SIB X of an SCell is received and when the first indication information is received, an MII message carrying an mbs-ServiceList is transmitted.

[0183] In another example, when the terminal device receives SIB X of the SCell and when the terminal device receives first indication information, or when the identifier of the MBS service that the terminal device is interested in is different from the identifier of the MBS service carried in the last transmitted MII message, the terminal device transmits an MII message carrying the mbs-ServiceList.

[0184] Optionally, for other possible implementation manners, please refer to the related descriptions of the method 100 for transmitting an MII message and the method 400 for transmitting an MII message, and the details will not be described again here.

[0185] This application further provides a method 500 for transmitting an MII message. In the method 500 for transmitting an MII message, the method 200 for transmitting an MII message may be combined with the method 400 for transmitting an MII message. Specifically, when SIB X of an SCell or PCell is received, whether or not to transmit an MII message carrying an mbs-ServiceList is determined by referring to whether first indication information has been received.

[0186] For example, when SIB X of an SCell or PCell is received and when the first indication information is received, an MII message carrying an mbs-ServiceList is transmitted.

[0187] In another example, when the terminal device receives SIB X of an SCell or PCell, and when the terminal device receives first indication information, or when the identifier of the MBS service of interest to the terminal device is different from the identifier of the MBS service carried in the last transmitted MII message, the terminal device transmits an MII message carrying an mbs-ServiceList.

[0188] Optionally, for other possible implementation manners, please refer to the related descriptions of the method 100 for transmitting an MII message and the method 200 for transmitting an MII message, and the details will not be described again here.

[0189] This application further provides a method 600 for transmitting an MII message. In the method 600 for transmitting an MII message, if SIB X of an SCell and a PCell is received, this triggers transmission of an MII message, and may be considered as transmitting an MII message carrying an mbs-ServiceList. Specifically, in the method 600 for transmitting an MII message, "SIB X of a primary cell or a secondary cell" in the method 200 for transmitting an MII message may be modified to "SIB X of a primary cell and a secondary cell." Optionally, for other possible implementation manners, reference may be made to the relevant description of the method 200 for transmitting an MII message. Details will not be described again here.

[0190] In the above embodiments, the description of the embodiments has its own focus. To avoid redundancy, for parts not described in detail in the embodiments, reference is made to the relevant descriptions in other embodiments. Furthermore, the combination layout between various implementation methods and optional implementation methods of other contents includes, but is not limited to, the combination layout of the above embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0191] To realize the functions of any of the communication methods provided in the embodiments of this application, an access network device, a user equipment, or a core network device may separately include a hardware structure and a software module, and may realize the above functions in the form of a hardware structure, a software module, or a combination of a hardware structure and a software module. One of the above functions may be performed through a hardware structure, a software module, or a combination of a hardware structure and a software module. Figures 6 and 7 are diagrams of possible structures of a communication device according to the embodiments of this application. The communication device may be configured to realize the functions of a terminal or a network device in the above method embodiments. Therefore, the beneficial effects of the above method embodiments can also be realized.

[0192] The communication device shown in Fig. 6 may include a communication unit 601. The communication unit 601 may include a transmitting unit and a receiving unit. The transmitting unit is configured to realize a transmitting function. The receiving unit is configured to realize a receiving function. The communication unit 601 may realize a transmitting function and / or a receiving function. The communication unit may also be described as a transceiver unit.

[0193] The communication device shown in FIG. 6 may be a terminal device, or may be a device within a terminal device.

[0194] In an optional implementation manner, the communication device may implement related operations of a terminal device in the method 100 for transmitting an MII message. The communication unit 601 is configured to receive a System Information Block (SIB) of a secondary cell (SCell), where the SIB includes information used to obtain a Multicast and Broadcast Service MBS Control Channel (MCCH) configuration of a Multicast and Broadcast Service. The communication unit 601 is further configured to send a Multicast and Broadcast Service Interest Information (MII) message, where the MII message carries an identifier of an MBS service of interest to the communication device.

[0195] Optionally, the communication device shown in FIG. 6 may include a processing unit 602 configured to set the content of the MII message.

[0196] For more detailed descriptions of the processing unit 602 and the communication unit 601, please refer to the relevant descriptions in the above method embodiments.

[0197] In another optional implementation manner, the communication device may implement related operations of a terminal device in the method 200 for transmitting an MII message. The communication unit 601 is configured to receive a system information block (SIB) of a secondary cell or a primary cell, where the SIB includes information used to obtain a multicast and broadcast service control channel (MCCH) configuration of a multicast and broadcast service (MBS). The communication unit 601 is further configured to send a multicast and broadcast service interest information (MII) message, where the MII message carries an identifier of an MBS service of interest to the communication device.

[0198] Optionally, the communication device shown in FIG. 6 may include a processing unit 602 configured to set the content of the MII message.

[0199] For more detailed descriptions of the processing unit 602 and the communication unit 601, please refer to the relevant descriptions in the above method embodiments.

[0200] In yet another optional implementation manner, the communication device may implement related operations of the terminal device in the method 300 for transmitting an MII message. The communication unit 601 is configured to receive first indication information. The first indication information instructs the communication device to report an identifier of a multicast and broadcast service (MBS) service. The communication unit 601 is further configured to send a multicast and broadcast service interest indication MII message. The MII message carries the identifier of the MBS service in which the communication device is interested.

[0201] Optionally, the communication device shown in FIG. 6 may include a processing unit 602 configured to set the content of the MII message.

[0202] For more detailed descriptions of the processing unit 602 and the communication unit 601, please refer to the relevant descriptions in the above method embodiments.

[0203] The communication device shown in FIG. 6 may be a network device, or may be a device within a network device.

[0204] In another optional implementation manner, the communication device may implement related operations of the network device in the method 300 for transmitting an MII message. The communication unit 601 is configured to send first indication information. The first indication information instructs the terminal device to report an identifier of a multicast and broadcast service (MBS) service. The communication unit 601 is further configured to receive a multicast and broadcast service interest indication MII message. The MII message carries the identifier of the MBS service in which the terminal device is interested.

[0205] For a more detailed description of the communication unit 601, please refer to the relevant description in the above method embodiment.

[0206] 7 may include a processor 701 and an interface circuit 702. The processor 701 and the interface circuit 702 are coupled to each other. It may be understood that the interface circuit 702 may be an interface circuit or an input / output interface. Optionally, the communication device shown in FIG. 7 may further include a memory 703 configured to store instructions to be executed by the processor 701, to store input data required by the processor 701 to execute the instructions, or to store data generated after the processor 701 executes the instructions.

[0207] The communication device is a terminal device or a device within the terminal device. The interface circuit 702 may execute S101 in Fig. 3, and the processor may set the content of the MII message. Alternatively, the interface circuit 702 may execute S201 in Fig. 4, and the processor 701 may set the content of the MII message. Alternatively, the interface circuit 702 may execute S301 in Fig. 5, and the processor 701 may set the content of the MII message.

[0208] The communication device is a network device or a device in a network device. The interface circuit 702 performs the operation of transmitting SIB X of the SCell in Fig. 3, the operation of transmitting SIB X of the primary cell or the secondary cell in Fig. 4, or the operation of transmitting first indication information in Fig. 5.

[0209] When the communication apparatus is a module used in a network device, the module in the network device realizes the functions of the network device in the above method embodiments. The module in the network device receives information from another module (e.g., a radio frequency module or an antenna) in the network device, and the information is transmitted to the network device by a terminal. Alternatively, the module in the network device transmits information to another module (e.g., a radio frequency module or an antenna) in the network device, and the information is transmitted to the terminal by the network device. The module in the network device here may be a baseband chip of the network device, or a DU or other module. The DU here may be a DU in an open radio access network (O-RAN) architecture.

[0210] It should be understood that the processor referred to in the embodiments of this application may be a CPU, or may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor, etc.

[0211] It can be understood that the memory referred to in the embodiments of this application may be volatile memory or nonvolatile memory, or may include volatile memory and nonvolatile memory. Nonvolatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM), and is used as an external cache. By way of example and not limitation, many types of RAM may be used, such as static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchlink dynamic random access memory (synchlink DRAM, SLDRAM), and direct rambus random access memory (direct rambus RAM, DR RAM).

[0212] It should be noted that when the processor is a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, the memory (storage module) may be integrated into the processor.

[0213] It should be noted that memory as described herein is intended to include, without being limited to, these and any other suitable types of memory.

[0214] It should be understood that the sequence numbers of the above processes do not mean the execution order in various embodiments of this application, and the execution order of the processes should be determined according to the functions and internal logic of the processes, and should not be construed as any limitation on the implementation process of the embodiments of this application.

[0215] Those skilled in the art may recognize that, in combination with the examples described in the embodiments disclosed in this specification, the modules and algorithm steps can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether a function is performed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to realize the described functions for each specific application, but the implementation method should not be considered to go beyond the scope of this application.

[0216] Those skilled in the art can clearly understand that for the purpose of convenient and concise description, the detailed operation processes of the above systems, devices and modules may refer to the corresponding processes in the above method embodiments, and the details will not be described again here.

[0217] In some embodiments provided in this application, it should be understood that the disclosed communication methods and devices may be implemented in other ways. For example, the described device embodiments are merely examples. For example, the module division is merely a logical functional division, and other divisions may be used in actual implementations. For example, multiple modules or components may be combined or integrated into other systems, or some features may be omitted or not implemented. Furthermore, the shown or discussed mutual couplings or direct couplings or communication connections may be realized by using some interfaces. Indirect couplings or communication connections between devices or units may be realized in electronic, mechanical, or other forms.

[0218] Modules described as separate components may or may not be physically separate, and components shown as modules may or may not be physical modules, i.e., may be located in one place or distributed across multiple network units. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

[0219] Furthermore, the functional modules in the embodiments of this application may be integrated into one processing module, or each of the modules may exist physically alone, or two or more modules may be integrated into one module.

[0220] When a function is realized in the form of a software function module and sold or used as an independent product, the function may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application may essentially, or some of the contributing parts or technical solutions may be realized in the form of a software product. A computer software product is stored in a storage medium and includes some instructions for instructing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or some of the steps of the method described in the embodiments of this application. A computer-readable storage medium may be any available medium that can be accessed by a computer. This is used as an example, but is not limited to this. The computer-readable storage medium may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and compact disc read-only memory (CD-ROM), universal serial bus flash drive, removable hard disk, or other optical disk storage, disk storage media, or other magnetic storage devices, or any other medium that can be used to carry or store contemplated program code in the form of instructions or data structures and that can be accessed by a computer.

[0221] The above description is merely a specific implementation of this application and is not intended to limit the scope of protection of the embodiments of this application. Any variations or substitutions that can be easily understood by those skilled in the art within the technical scope disclosed in the embodiments of this application shall fall within the scope of protection of the embodiments of this application. Therefore, the scope of protection of the embodiments of this application should be subject to the scope of protection of the claims.

Claims

1. 1. A method for transmitting a multicast and broadcast service interest indication message, applied to a communication device, comprising: receiving a system information block (SIB) of a secondary cell (SCell), the SIB including information used to obtain a multicast and broadcast service control channel (MCCH) configuration of a multicast and broadcast service (MBS); receiving an MBS service provided by the SCell by using an MCCH configured by using the MCCH configuration; determining an identifier of an MBS service of interest to the communication device based on the MBS service provided by the SCell; transmitting a Multicast and Broadcast Service Interest Indication (MII) message, the MII message carrying the identifier of the MBS service of interest to the communication device; A method comprising:

2. The step of transmitting an MII message includes: transmitting the MII message if SIBs of all cells in a cell set have not been received since the last time the MII message was transmitted; The method of claim 1 , wherein the cell set includes one or more cells that provide radio resources to the communication device.

3. The step of transmitting an MII message includes:

2. The method of claim 1, further comprising: transmitting an MII message if the identifier of the MBS service of interest to the communication device is different from the identifier of an MBS service carried in a last transmitted MII message.

4. The method according to claim 1 , wherein the SCell is an SCell in a master cell group (MCG) and / or a secondary cell group (SCG) that provides radio resources to the communication device.

5. The method of claim 2 , wherein the cell set includes one or more cells that provide radio resources to the communication device after the communication device last transmitted an MII message.

6. The method of claim 1 , wherein the SIB for the SCell is received through dedicated signaling.

7. The method of claim 1 , wherein the MII message further carries at least one of MBS frequency information and MBS priority information.

8. A communication device including a communication unit and a processing unit, The communication unit is configured to receive a system information block (SIB) of a secondary cell (SCell), the SIB including information used to obtain a multicast and broadcast service control channel (MCCH) configuration of a multicast and broadcast service (MBS); The communication unit is further configured to receive an MBS service provided by the SCell by using an MCCH configured by using the MCCH configuration; The processing unit is configured to determine an identifier of an MBS service of interest to the communication device based on the MBS service provided by the SCell; The device, wherein the communication unit is further configured to transmit a Multicast and Broadcast Service Interest Indication (MII) message, the MII message carrying the identifier of the MBS service of interest to the communication device.

9. The communication unit transmitting an MII message includes: transmitting the MII message if SIBs of all cells in a cell set have not been received since the last transmission of the MII message; The apparatus of claim 8 , wherein the cell set includes one or more cells that provide radio resources to the communication device.

10. The communication unit transmitting an MII message includes:

9. The device of claim 8, wherein the MII message is transmitted if the identifier of the MBS service of interest to the communication device is different from the identifier of the MBS service carried in the last transmitted MII message.

11. The device according to claim 8 , wherein the SCell is an SCell in a Master Cell Group (MCG) and / or a Secondary Cell Group (SCG) that provides radio resources to the communication device.

12. The apparatus of claim 9 , wherein the cell set includes one or more cells that provide radio resources to the communication device after the communication device last transmitted an MII message.

13. The apparatus of claim 8 , wherein the SIB for the SCell is received through dedicated signaling.

14. The apparatus according to claim 8 , wherein the MII message further carries MBS frequency information and MBS priority information.

15. A communication device including a processor and an interface circuit, 8. A communication device, wherein the interface circuit is configured to receive signals from a communication device other than the communication device and transmit the signals to the processor, or transmit signals from the processor to a communication device other than the communication device, and the processor is configured to implement the method of any one of claims 1 to 7 by using logic circuits or executing code instructions.

16. 1. A computer-readable storage medium, comprising: A computer-readable storage medium storing a computer program or instructions, the computer program or instructions implementing the method of any one of claims 1 to 7 when executed by a communication device.

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