Method and related apparatus for transmitting multicast and broadcast service interest indication messages - Patents.com

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 technologies, and in particular 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 to 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, two steps are required for the configuration of a broadcast service. One step is that a terminal needs to receive a System Information Block (SIB) of a primary cell (PCell) including information used to obtain a Multicast and Broadcast Service Control Channel (MBS Control Channel, MCCH) configuration of an MBS, and needs to receive a SIB of a PCell including a mapping relationship between a frequency and an MBS or an MBS frequency selection 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 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, the application provides a method for transmitting a multicast and broadcast service interest indication message. The method may be executed 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 disposed 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 description.

[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 sends 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 an 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 is 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 sends an MII message including: If the SIB X of all cells in a cell set has not been received after the last MII message is 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 the SIB X of a SCell, and if the terminal device has not received the SIB X of all cells in the cell set after the last MII message is sent, 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 transmits 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 sends an MII message including: If 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 sends an MII message; In other words, if the terminal device receives SIB X of SCell, and 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 sends an 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 flexibly manner.

[0015] According to a second aspect, the 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 disposed in the terminal device and configured to implement the functions of the terminal device, or other components 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 description.

[0016] The method includes: a terminal device receives first indication information, the first indication information instructs 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 that is of interest to the terminal device.

[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 the 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 a cell need to report MII messages may be introduced into the system message. Alternatively, the system message implicitly indicates whether all terminal devices in a 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 can determine whether to report the MII message carrying the 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 the 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 the delay and signaling overhead caused by the reconfiguration when the resource or scheduling information configured for the MBS service is inappropriate.

[0021] According to a third aspect, the 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 disposed 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 is described in terms of a network device. An example in which a network device is used as an implementation entity is used for explanation.

[0022] The method includes: a network device sends first indication information, the first indication information instructs 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 carries an identifier of the MBS service that is of interest to the terminal device.

[0023] In the method, it is seen that the network device indicates 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 knows the identifier of the MBS service that the terminal device is interested in in time, and can thereby timely schedule the MBS service for the terminal device.

[0024] Optionally, the first indication information is carried in a system message. The network device may use the system message to explicitly or implicitly indicate whether all terminal devices in the cell need to report an MII message carrying an identifier of the MBS service.

[0025] Optionally, the first indication information is received through dedicated signaling.In this way, when the network side has the MII messages of some terminal devices but does not have the MII messages of other terminal devices, the network device can accurately instruct other terminal devices to report MII messages based on the 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 the problem that the resource or scheduling information configured for the MBS service is inappropriate and needs to be reconfigured 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.

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

[0028] According to a fourth aspect, the application provides a communication device. The communication device may be a terminal device, a device in a terminal device, or a device usable in combination with a terminal device. The communication device may alternatively be a chip system. The communication device may perform the method in the first aspect or the 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, a communication device may include a communication unit and may perform the communication method according to the first aspect. The communication unit includes: 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 being unable 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, when the identifier of an MBS service of interest to the communication device is different from the identifier of the MBS service carried in the last sent MII message.

[0034] In yet another optional implementation manner, the communication unit sends an MII message, specifically, when the SIB X of all cells in the cell set has not been received after the last MII message was sent, and when 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.

[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 transmitted 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, where the first indication information instructs 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 an identifier of an 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 method and beneficial effects in the first or second aspect.

[0045] According to a fifth aspect, the application provides a communication device. The communication device may be a network device, a device in a network device, or a device usable in combination with a network device. The communication device may perform the method in the first aspect or the third 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.

[0046] In an optional implementation, the apparatus includes a communication unit. The communication unit is configured to send first indication information, where the first indication information instructs the 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 of interest to the terminal device.

[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, reference is made 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, the storage medium storing instructions, the computer program or instructions being executed by a communication device to realize a method as set forth in 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 which, 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 comprising 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 comprises 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 description of the drawings]

[0053] [Figure 1]FIG. 2 is a diagram of a transmission architecture of an MBS according to an embodiment of this application. [Diagram 2] 1 is a diagram of various types of cells according to an embodiment of the present application. [Diagram 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. [Diagram 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] FIG. 2 is a structural diagram of a communication device according to an embodiment of this application. [Figure 7] FIG. 2 is a structural diagram of another communication device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] In the embodiment of this application, the network device may also be referred to as an access network device. The 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. The RAN device is mainly a wireless network device in a 3GPP network. The AN device may be an access network device not defined by 3GPP. The 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. The RAN device may include various types of base stations, such as macro base stations, micro base stations (which may also be 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 long term evolution (LTE) systems, and in fifth generation (5G), sixth generation (6G) or even seventh generation (7G) systems, a network device may be a RAN or next-generation Node base station (gNB), evolved Node B (eNB or eNodeB), network device controller (BSC), network device transceiver station (BTS), home network device (e.g., home evolved NodeB or home NodeB, HNB), baseband unit (BBU), access point (AP), wireless relay node, wireless backhaul node, transmission reception point (TRP), transmission point (TRP), transmission control point (TC), transmission control unit (TCU ... The antenna panel (including a plurality of antenna panels) of one or more groups of network devices in a 5G system may be referred to as an antenna panel (TP), etc., or as one or more groups of network devices in a 5G system, or as 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, the gNB or 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 realizes some functions of the gNB or transmission point, and the DU realizes some functions of the gNB or transmission point. For example, the CU realizes functions of a radio resource control (RRC) layer and a packet data convergence protocol (PDCP) layer, and the DU realizes functions of a radio link control (RLC) layer, a media access control (MAC) layer, and a physical (PHY) layer. Information in the RRC layer eventually 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 transmitted by the DU and RU. It can be understood that the network device may be a device including a CU node, a DU node, or a CU node and a DU node. Optionally, the network device may alternatively be an auxiliary communication device, for example, a satellite.

[0056] In the embodiment of this application, the terminal is a device having a wireless transceiver function, and may be a device located on the ground, a device located on the water (e.g., on a ship), or a device located in the air (e.g., on an aircraft, a balloon, or a satellite), including an indoor device or 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 in a smart home, or a wearable terminal device, etc. In some cases, a terminal may also be referred to as a terminal device, user equipment (UE), an access terminal device, an in-vehicle terminal, an industrial control terminal, a UE unit, a UE station, a mobile station, a remote station, a remote terminal device, a mobile device, a UE agent, a 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 LTE communication systems, 5G (or called new radio (NR)) communication systems, or transitional systems between LTE and 5G communication systems. The transitional systems may also be called 4.5G communication systems, or obviously future communication systems, such as 6th generation (6G) or even 7th generation (7G) systems. 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 are also applicable to similar technical problems.

[0058] In order to clearly describe the technical solutions in the embodiments of this application, terms such as "first" and "second" are used to distinguish between the same or similar items whose functions and effects are basically the same in the embodiments of this application. Those skilled in the art may 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 the same or similar items whose functions and effects are basically the same, but are not limited in their 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, namely, 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 the embodiments of this application.

[0060] 1.MBS Transmission Architecture

[0061] MBS is a service targeted to multiple terminal devices. The transmission architecture of MBS is shown in Figure 1, including 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 MBS data to the access network device. Finally, the access network device transmits 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 MBS sessions, 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. For one MBS radio bearer, there are two transmission modes. As shown in Figure 1, the first transmission mode may be a point to multi-point (PTM) transmission mode. The second transmission mode may be a point to point (PTP) transmission mode.

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

[0064] For example, two steps are required for the configuration of a broadcast service. One step is that the terminal needs to receive a System Information Block (SIB) of a primary cell (PCell) including information used to obtain a multicast and broadcast service control channel (MBS Control Channel, MCCH) configuration of the MBS, and needs to receive a SIB of the PCell including 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 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 services, multicast sessions, and multicast services are equivalent concepts in this application and may be substituted for each other. Correspondingly, broadcast services, broadcast sessions, and broadcast services 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 the MBS and the names of the SIBs containing the mapping relationship between the frequency and the MBS or MBS frequency selection area identifier are not limited in this application. For ease of explanation, the SIB containing the mapping relationship between the frequency and the MBS or MBS frequency selection area identifier is called SIB X1 for short, and the SIB containing information used to obtain the MCCH configuration of the MBS is called SIB X for short. 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 the frequency and the MBS or MBS frequency selection area identifier is called SIB 21, and the SIB containing information used to obtain the MCCH configuration of the 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 (TMGI). Thus, 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 sending 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 execute the decision process in the second part to decide 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 in RRC_CONNECTED and supporting 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 providing a broadcast service. (3) The start or end of an MBS session. (4) The identifier of the MBS service in which the terminal device is interested 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 a 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 execute 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> When 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 time an MII message was transmitted, 3> If the MBS frequency information of interest to the terminal device (i.e., mbs-FreqList) is not available, 4> Set the contents 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 determination mechanism of the second part, the terminal device may determine the content of the MII message according to the setting mechanism of the content of the MII message of the third part. The process of the setting mechanism of the content of the MII message 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 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 preferentially receive 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 the mbs-ServiceList in descending order of the degree of interest 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] The SIB X of the PCell includes, but is not limited to, the following descriptions: SIB X is a SIB X for a multicast service provided by the PCell, SIB X is a SIB X for a multicast service provided by the PCell, or SIB X is a SIB X provided for a terminal device to receive a multicast service on the PCell.

[0078] Correspondingly, the SIB X1 of the PCell includes, but is not limited to, the following descriptions: SIB X1 is a SIB X1 for a multicast service provided by the PCell, SIB X is a SIB X1 for a multicast service provided by the PCell, or SIB X1 is a 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, 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. Secondary cells are serving cells that are added when the terminal device performs an RRC reconfiguration and are 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. The 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 a carrier aggregation (CA) technique. The PSCell in the SCG and the SCell in the SCG are also combined by using a carrier aggregation technique.

[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, the primary cell in MCG is called PCell, other serving cells are called SCell, primary cell in SCG is called PSCell, other serving cells are called SCell. Optionally, PCell in MCG and PSCell in SCG may also be called 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 in which a secondary cell may provide a broadcast service, for example, when only the secondary cell can provide a broadcast service, or when both the PCell and the secondary cell can provide a 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 in which 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 this 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 provide 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 the SCell indicates: 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 an MCCH configuration of the MBS. The terminal device may receive the MBS service that can be provided by the SCell by using the MCCH that is 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 in which a secondary cell can provide a broadcast service, 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, thereby enabling the network side to know the MBS service of interest to the terminal device.

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

[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 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 transmitted.

[0097] In other words, if the terminal device receives SIB X for a SCell, and if the terminal device has not received SIB X for all cells in the cell set since the terminal device last transmitted an MII message, the terminal device transmits an MII message carrying the 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 provide radio resources to the terminal device before the current time and cells that currently provide radio resources to the terminal device. In yet other cases, the cell set includes one or more cells that have provided radio resources to the terminal device since the terminal device last transmitted an MII message. In yet other cases, the cell set includes cells that currently provide radio resources to the terminal device. In 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 will transmit an MII message carrying mbs-ServiceList if SIB X of the current SCell is received. In this implementation, it can be seen that when the terminal device receives SIB X of the SCell, if the terminal device has not received SIB X of all cells in the cell set after the terminal device has last transmitted an MII message, the terminal device may report an MII message carrying mbs-ServiceList.

[0099] For example, the cell set includes cell 1 and cell 2 that provide radio resources to the terminal device before the current time, and cell 3 that provides radio resources to the terminal device at the current time. At time T1, when the terminal device is 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 reports 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 report an MII message carrying mbs-ServiceList again. In this way, when the terminal device moves from cell 1 to cell 2, the access network device in cell 1 may forward the MII message carrying mbs-ServiceList and reported by the terminal device to cell 2. However, since cell 2 does not provide SIB X, and perhaps cell 2 cannot support MBS, when the terminal device moves to cell 3, the MII message carrying mbs-ServiceList is not forwarded to the network device of cell 3 because the terminal device does not identify 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 of cell 2 to the access network device of cell 3 does not include mbs-ServiceList. However, if cell 3 supports MBS, when the terminal device receives SIB X of cell 3, the terminal device may timely report the MII message carrying mbs-ServiceList, thereby notifying the network side of the identifier of the service that the terminal device is interested in, so that the network side can timely and accurately schedule the MBS service to the terminal device.

[0100] In another example, the cell set includes cell 1, and the terminal device is stationed in cell 1 before the current time. At time T1, cell 1 provides SIB X1 but does not provide SIBx. Thus, 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 an MII message that does not carry mbs-ServiceList, cell 1 does not provide SIB X. Thus, at time T2, cell 1 provides SIB X, and the terminal device may timely report an MII message that carries mbs-ServiceList, thereby informing the network side of the identifiers of the services that interest the terminal device, so that the network side can timely schedule MBS services to 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 of interest to the terminal device has changed.

[0102] In other words, when a terminal device receives SIB X of an SCell and the identifier of an 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 transmit 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 transmitted and whether the identifier of the MBS service of interest to the terminal device has 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 transmits an MII message carrying the mbs-ServiceList.

[0105] This application provides a method 200 for transmitting a multicast and broadcast service interest indication message. In a scenario in which 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 a 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 a SCell in an MCG and / or a SCell in an SCG.

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

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

[0113] Optionally, when the terminal device receives SIB X of 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 of interest to the terminal device in the secondary cell. When the terminal device receives SIB X of the 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 the 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, one mbs-ServiceList may be added to the MII message, compared with the case where the MII message carries one mbs-ServiceList. 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 in which both the primary cell and the secondary cell may provide broadcast services.

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

[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 the mbs-ServiceList by referring to whether SIB X of all cells in the cell set have been received since the last time the MII message was transmitted.

[0118] In other words, when the terminal device receives the SIB X of the primary cell or the secondary cell, and has not received the SIB X of all cells in the cell set after the terminal device last transmitted the MII message, the terminal device transmits the MII message carrying the mbs-ServiceList. Specifically, when the terminal device has not received the SIB X of all cells in the cell set after the terminal device last transmitted the MII message and before receiving the SIB X of the current primary cell or the secondary cell, the terminal device transmits the MII message carrying the mbs-ServiceList if the SIB X of the current primary cell or the secondary cell is received. In this implementation, when the terminal device receives the SIB X of the primary cell or the secondary cell, if the terminal device has not received the SIB X of all cells in the cell set after the terminal device last transmitted the MII message, it can be seen that the terminal device may report the MII message carrying the 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 cell 1-1 and cell 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. Thus, 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, since 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, so network device 2 does not forward the MII message carrying mbs-ServiceList to network device 3.In other words, when the terminal device is handed over from the network device 2 to the network device 3, the RRC configuration forwarded by the network device 2 to the network device 3 does not include the mbs-ServiceList. However, if the cell 3-2 supports MBS, when the terminal device can receive the SIB X of the cell 3-2, the terminal device may timely report an MII message carrying the mbs-ServiceList, thereby notifying the network side of the identifiers of the services that the terminal device is interested in, so as to enable the network side to timely schedule the MBS service 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 served by cell 1-1 before the current time. At time T1, cell 1-1 or cell 1-2 provides SIB X1 but does not provide SIBx. 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 an MII message that does not carry mbs-ServiceList, neither cell 1-1 nor cell 1-2 provides SIB X. Thus, 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 informing the network side of the identifiers of the services that the terminal device is interested in, so that the network side can timely schedule MBS services to 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 sends an MII message carrying the mbs-ServiceList.

[0124] Implementation method 2-3: 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 SIB X of all cells in the cell set have been received since the last time the MII message was sent and whether the identifier of the MBS service of interest to the terminal device has 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 the mbs-ServiceList.

[0126] Based on the mechanism in the method for transmitting an MII message, in which a terminal device may decide whether to send an MII message when the terminal device 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) 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 and / or the secondary cell.

[0128] Optionally, condition (7) may be that the terminal device is connected to the primary cell and / or the secondary cell to which the SIB X is transmitted, or that the terminal device receives the SIB X of the primary cell and / or the 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 of a PCell or SCell is received, and If the 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, where the MII message carries an 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 time an MII message was transmitted, 3> If the MBS frequency information of interest to the terminal device (i.e., mbs-FreqList) is not available, 4> Set the contents 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 send an MII message may alternatively be performed separately as several steps. For example, the process steps in the mechanism for determining whether to send an MII message may only include: 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 sent an MII message, setting the content of the MII, sending an MII message, and the MII message carrying an identifier of an MBS service. The combination manner of the process steps in the mechanism for determining whether to send 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 with reference 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 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 bearers and any MBS radio bearers, 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 the mbs-ServiceList in descending order of the degree of interest 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 the terminal device receives SIB X of 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 of interest to the terminal device in the secondary cell. When the terminal device receives SIB X of the 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 the 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, one mbs-ServiceList may be added to the MII message, compared with the case where the MII message carries one mbs-ServiceList. 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 the conditions (1) to (7) in the first part and the terminal device receives the SIB X1 of the primary cell or the secondary cell, the terminal device executes the process of the mechanism described in step 1> to step 5> in the second part to determine whether the terminal device reports the MII message. Furthermore, after step 1> is satisfied, step 2>: the case where the terminal device has not sent 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 sending 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 the SIB X1 of the primary cell or the secondary cell is received at time T1 and the SIB X is not received, the setting content of the MII message includes mbs-FreqList and mbs-Priority, but does not include mbs-ServiceList. In addition, 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 the conditions (1) to (7) in the first part and the terminal device receives the SIB X of the primary cell or the secondary cell, the terminal device executes the process of the mechanism described in step 1> to step 5> in the second part to determine whether the terminal device reports the MII message. Furthermore, after step 1> is satisfied, the conditions of steps 2> and 3> other cases are not satisfied, so step 3> is executed, otherwise, the SIB X of the PCell or SCell is received, and step 4>: if the terminal device has not received the SIB X of all cells in the cell set since the terminal device last transmitted the MII message, the terminal device may execute step 5>: 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 the SIB X of the primary cell or the secondary cell is received at time T2, the setting content of the MII message includes mbs-FreqList, mbs-Priority, and mbs-ServiceList. In addition, the terminal device sends an MII message carrying mbs-FreqList, mbs-Priority and mbs-ServiceList.

[0140] Optionally, the terminal device may receive the SIB X1 of the primary cell or the secondary cell at the time T1 to satisfy the condition (6) in the first part. Therefore, 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 may receive the SIB X of the primary cell or the secondary cell at time T2 to satisfy condition (7) in the first part. Therefore, 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, assume that after the terminal device enters the RRC_CONNECTED state:

[0143] At time T1, if the terminal device satisfies at least one of the conditions (1) to (7) in the first part and the terminal device receives SIB X1 and SIB X of the primary or secondary cell, the terminal device executes the process of the mechanism described in step 1> to step 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 sent an MII message since the last time it was in RRC_CONNECTED state is executed, and the terminal device may execute step 4>: setting the content of the MII message and sending the MII message. Refer to the mechanism for setting the content of the MII 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 is received at time T1 and SIB X is also received, the setting content of the MII message includes mbs-FreqList, mbs-Priority and mbs-ServiceList. In addition, 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. Further, step <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 may receive the SIB X1 and SIB X of the primary cell or the secondary cell at time T1 to satisfy condition (7) in the first part. Therefore, 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 may receive the SIB X1 and SIB X of the primary cell or the secondary cell at time T2 to satisfy condition (7) in the first part. Therefore, 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 SIBx is provided by the PCell or SCell, if SIBx 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 SIBx and all SCells (if available) also not provided SIBx), or 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, Sets the contents of the MII message and triggers the transmission of the MII message (sets the contents of MBS Interest Indication and initiates 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. else if SIBx is provided by one cell of the MCG, if SIBx has not been received for all cells in the MCG since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cells of MCG not broadcasting SIBx, or 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, Sets the contents of the MII message and triggers the transmission of the MII message (sets the contents of MBS Interest Indication and initiates the transmission of MBSInterestIndication message).

[0151] Implementation method 3-3 is described for MCG. If SIBx is provided by the PCell or SCell of MCG, if SIB X of the PCell and SIB X of all SCells in MCG have not been received 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 SIBx, or 4> 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 SIBx is provided by serving cell(s), if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell of serving cell(s) not broadcasting SIBx, or 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 since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell of serving cell(s) not broadcasting SIBx, or 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 SIBx is provided by MCG, then if SIBx of all cells in the MCG has not been received since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell of MCG not broadcasting SIBx, or 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 method 3-7 is described for MCG. else if SIBx is provided by at least one cell of MCG, if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell of MCG not broadcasting SIB X, or 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 method 3-8 is described for MCG. else if SIB X is provided for the PCell or SCell of MCG, if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell of MCG not broadcasting SIB X, or if the set of MBS broadcast services of interest determined in accordance with 5.x.4.4 is different from 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 SIBx for the PCell or ScellSIBx 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 UE transmitted the MBS Interest Indication, the UE connected to PCell not broadcasting SIB X and SCell not broadcasting Scell ​​SIB X, or 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 MBSInterestIndication message).

[0158] Implementation method 3-10 is described for MCG. 3> If SIBx of the PCell in MCG or ScellSIBx 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 UE transmitted the MBS Interest Indication, the UE connected to PCell not broadcasting SIB X and all SCells in MCG not broadcasting Scell ​​SIB X, or 4> 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: else if SIBx or ScellSIBx is provided by serving cell(s), if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all of serving cell(s) not broadcasting SIB X and / or ScellSIB X, or 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: else if SIBx or ScellSIBx is provided by at least on cell, 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 ScellSIB X, or 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. else if SIBx or ScellSIBx is provided by at least one cell of MCG, if since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell of MCG not broadcasting SIB X and ScellSIBx, or 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 since the last time the UE transmitted the MBS Interest Indication, the UE connected to all cell of MCG not broadcasting SIBx and / or ScellSIBx, or 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 SIBx or SCellSIBx is provided, 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 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] Achievement methods 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 a multicast and broadcast service interest indication message, thereby enabling a terminal device to timely transmit an MII message carrying an identifier of an MBS service 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 sends first indication information. Correspondingly, a terminal device receives the first indication information. The first indication information instructs a communication device to report an identifier of a multicast and broadcast service (MBS) service.

[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 sends an MII message carrying an identifier of an MBS service of interest to the terminal device. Correspondingly, 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 sends 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 sends indication information indicating that the terminal device does not need to report an identifier of an 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 does 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 an MII message is introduced into the system message. In this way, when the network does not have an MII message forwarded by other network devices, the network sends an indication indicating that all UEs in the cell need to report an MII message. In another example, some information element (IE) or field may be used for implicit indication in the system message 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 perform a decision by itself, but can know whether an MII message needs to be reported, or whether an MII message including mbs-FreqList needs to be reported, by reading the system message sent by the network device.

[0171] In another optional realization 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 perform a decision by itself, and can know whether an MII message needs to be reported or whether an MII message including mbs-FreqList needs to be reported by reading the dedicated signaling sent by the network device. When the network device has the MII message of the terminal device, the network device does not need to instruct the terminal device to report the MII message. 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 the secondary cell to which the SIB X is transmitted, or that the terminal device receives the SIB X of the primary cell and / or the 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 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 transmit (or indicate) the first indication information after the last time the MII message was transmitted (if since the last time the UE transmitted the MBS Interest Indication, the UE connected to MCG not indicating MII-ind), or 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 identifiers of the MBS services in the mbs-ServiceList are sorted in decreasing order of interest of 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, referring to whether first indication information is received, it is determined whether to transmit an MII message carrying an mbs-ServiceList.

[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 a terminal device receives SIB X of an SCell, and when the terminal device receives first indication information, or when the identifier of an MBS service of interest to the terminal device is different from the identifier of an MBS service carried in the last transmitted MII message, the terminal device transmits an MII message carrying an 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, it is determined whether to transmit an MII message carrying an mbs-ServiceList by referring to whether first indication information is 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 a terminal device receives SIB X of an SCell or PCell, and when the terminal device receives first indication information, or when the identifier of an MBS service of interest to the terminal device is different from the identifier of an 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 SCell and PCell is received, this may trigger the 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, refer to the related description of the method 200 for transmitting an MII message. Details are not described again here.

[0190] In the above embodiments, the description of the embodiments has its own focus. In order to avoid redundancy, for the parts not described in detail in the embodiments, refer to the relevant descriptions in other embodiments. In addition, the layout of combinations between various implementation methods and optional implementation methods of other contents includes but is not limited to the layout of combinations 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 any method function in the communication method provided in the embodiments of this application, the access network device, the user equipment or the core network device may separately include a hardware structure and a software module, and realize the above function 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. Thus, 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 the relevant operation of the 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 a more detailed description 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 the relevant operation of the terminal device in the method 200 for transmitting the 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 for obtaining 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 the 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 a more detailed description 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 the relevant operation 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 an identifier of the MBS service that is of interest to the communication device.

[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 a more detailed description 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 an identifier of an MBS service that is of interest to the terminal device.

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

[0206] The communication device shown in Fig. 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 in a 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 the network device. The interface circuit 702 performs the operation of transmitting the SIB X of the SCell in Fig. 3, the operation of transmitting the SIB X of the primary cell or the secondary cell in Fig. 4, or the operation of transmitting the first indication information in Fig. 5.

[0209] When the communication device is a module used in a network device, the module in the network device realizes the function of the network device in the above method embodiment. The module in the network device receives information from other modules (e.g., radio frequency modules or antennas) in the network device, and the information is transmitted to the network device by the terminal. Alternatively, the module in the network device transmits information to other modules (e.g., radio frequency modules or antennas) 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 may be 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 a volatile memory or a non-volatile memory, or may include a volatile memory and a non-volatile memory. The non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a 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. 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 manner 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 be referred 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 method and device may be realized in other ways. For example, the described device embodiment is merely an example. For example, the module division is merely a logical functional division, and may be divided in other ways in actual implementation. For example, multiple modules or components may be combined or integrated into other systems, or some features may be ignored 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., 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 the 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 such understanding, the technical solution of this application may be essentially realized, or some of the contributing parts or technical solutions may be realized in the form of a software product. The 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 execute all or part of the steps of the method described in the embodiments of this application. The 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 thereto. 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 manner of this application, and is not intended to limit the protection scope of the embodiments of this application. Any variation or replacement that a person skilled in the art can easily understand within the technical scope disclosed in the embodiments of this application shall fall within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be subject to the protection scope of the claims.

Claims

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); transmitting a Multicast and Broadcast Service Interest Indication (MII) message, the MII message carrying an identifier of an MBS service of interest to the communication device; The method includes:

2. The step of transmitting an MII message includes: transmitting the MII message if the SIBs of all cells in a cell set have not been received since the MII message was last 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: The method of claim 1 , further comprising: transmitting the MII message if the identifier of the MBS service of interest to the communication device is different from an 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 according to claim 1 , wherein the SIB for the SCell is received through dedicated signaling.

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

8. A method for transmitting a multicast and broadcast service interest indication message, applied to a communication device, comprising: receiving first indication information, the first indication information instructing the communication device to report an identifier of a Multicast and Broadcast Service (MBS) service; transmitting a Multicast and Broadcast Service Interest Indication (MII) message, the MII message carrying an identifier of an MBS service of interest to the communication device; The method includes:

9. The first indication information is carried in a system message; or The first indication information is received through dedicated signaling, or The method of claim 8 , wherein the first indication information is carried in a message in a random access procedure.

10. A method for transmitting a multicast and broadcast service interest indication message, applied to a communication device, comprising: transmitting first indication information, the first indication information instructing a terminal device to report an identifier of a multicast and broadcast service (MBS) service; receiving a Multicast and Broadcast Service Interest Indication (MII) message, the MII message carrying an identifier of an MBS service of interest to the terminal device; The method includes:

11. The first indication information is carried in a system message; or The first indication information is received through dedicated signaling, or The method of claim 8 , wherein the first indication information is carried in a message in a random access procedure.

12. A communication device, comprising: A communication unit 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 transmit a Multicast and Broadcast Service Interest Indication (MII) message, the MII message carrying an identifier of an MBS service of interest to the communication device.

13. Specifically, the communication unit sends an MII message. transmitting the MII message if the SIB of all cells in a cell set has not been received since the MII message was last transmitted; The apparatus of claim 12 , wherein the cell set includes one or more cells that provide radio resources to the communication device.

14. Specifically, the communication unit sends an MII message. The apparatus of claim 12, further comprising: transmitting the MII message if the identifier of the MBS service of interest to the communication device is different from an identifier of an MBS service carried in a last transmitted MII message.

15. The device according to claim 12 , 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.

16. The apparatus of claim 13 , wherein the set of cells includes one or more cells that provide radio resources to the communication device after the communication device last transmitted an MII message.

17. The apparatus of claim 12 , wherein the SIB for the SCell is received through dedicated signaling.

18. The apparatus of claim 12 , wherein the MII message further carries at least one of MBS frequency information and MBS priority information.

19. A communication device, comprising: a communication unit 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; The communication unit is further configured to transmit a Multicast and Broadcast Service Interest Indication (MII) message, the MII message carrying an identifier of an MBS service of interest to the communication device.

20. The first indication information is carried in a system message; or The first indication information is received through dedicated signaling, or The apparatus of claim 19 , wherein the first indication information is carried in a message in a random access procedure.

21. A communication device, comprising: A communication unit configured to transmit first indication information, the first indication information instructing a terminal device to report an identifier of a multicast and broadcast service (MBS) service; The apparatus, wherein the communication unit is further configured to receive a Multicast and Broadcast Service Interest Indication (MII) message, the MII message carrying an identifier of an MBS service of interest to the terminal device.

22. The first indication information is carried in a system message; or The first indication information is received through dedicated signaling, or The apparatus of claim 21 , wherein the first indication information is carried in a message in a random access procedure.

23. A communication device including a processor and an interface circuit, A communication device, wherein the interface circuitry 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 or the method of claim 8 or 9 by using logic circuits or executing code instructions.

24. A communication device including a processor and an interface circuit, 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 claim 10 or 11 by using logic circuits or executing code instructions.

25. 1. A computer-readable storage medium, comprising: The storage medium stores a computer program or instructions, and when the computer program or the instructions are executed by a communication device, the method according to any one of claims 1 to 7 is realized, or the method according to claim 8 or 9 is realized. A computer-readable storage medium.

26. 1. A computer-readable storage medium, comprising: A computer-readable storage medium storing a computer program or instructions, the computer program or instructions being executed by a communication device to implement the method of claim 10 or 11.

27. 1. A computer program product comprising: A computer program product which, when executed on a computer, enables the computer to carry out the method according to any one of claims 1 to 7 or to carry out the method according to claim 8 or 9.

28. 1. A computer program product comprising: A computer program product which, when executed on a computer, enables said computer to carry out the method according to claim 10 or 11.

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