Communication method and device

Abstract

This application provides a communication method and apparatus for solving the problem of low accuracy of multicast capability reporting of terminal devices. The method includes determining capability information and sending the capability information to an access network device, where the capability information indicates a multicast service receiving capability corresponding to a band and / or a multicast service receiving capability corresponding to a component carrier (CC). The capability information indicates a multicast service capability at a band level or a component carrier level, improving the multicast capability reporting accuracy, thereby enabling the access network device to provide a multicast service and / or a unicast service based on the refined capability information.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to Chinese Patent Application No. 202111202345.1, entitled "COMMUNICATION METHOD AND APPARATUS," filed with the State Intellectual Property Office of the People's Republic of China on October 15, 2021, the entire contents of which are incorporated by reference. In addition to the entire contents of Application No. 202111202345.1, this application claims priority to certain contents of Chinese Patent Application No. 202210952975.9, entitled "COMMUNICATION METHOD AND APPARATUS," filed with the State Intellectual Property Office of the People's Republic of China on August 9, 2022, the contents of which are incorporated by reference.

[0002] [Technical field] This application relates to the field of communications technology, and more particularly to communications methods and devices. [Background technology]

[0003] A multimedia broadcast multicast service (MBMS) or groupcast / multicast broadcast service (MBS) is a service, such as live broadcast and scheduled program playback, primarily aimed at multiple user equipments (UEs).

[0004] In long term evolution (LTE), the access network device may obtain the UE capability information in a capability query process, where the UE capability information includes MBMS capability information.

[0005] Currently, the MBMS capability information designed for LTE is at the UE level and only supports reporting the maximum bandwidth used for MBS. However, this method cannot accurately report the multicast capability of the UE. Therefore, how to accurately report the multicast capability of the UE still needs to be further studied. Summary of the Invention

[0006] This application provides a communication method and apparatus for solving the problem of low accuracy in reporting multicast capabilities of terminal devices.

[0007] According to a first aspect, this application provides a communication method. The method may be performed by a first communication apparatus. The first communication apparatus may be a communication device, or may be a communication apparatus, such as a chip, capable of supporting the communication device in implementing functions required in the method. For example, the first communication apparatus may be a terminal device, a chip disposed in the terminal device and configured to implement functions of the terminal device, or another component configured to implement functions of the terminal device. In the following description process, an example in which the first communication apparatus is a terminal device will be used for explanation.

[0008] The method includes: a terminal device determines capability information and sends the capability information to an access network device, where the capability information indicates a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier (CC).

[0009] In this embodiment of the present application, the terminal device may indicate multicast capability at the band (also called frequency band) level and / or CC level by using capability information, thereby improving multicast capability reporting accuracy and enabling the access network device to obtain refined capability information. In a possible implementation, the access network device may provide multicast services and / or unicast services based on the refined capability information, for example, may configure or select communication parameters for the multicast services and / or unicast services based on the refined capability information.

[0010] In a possible design, the capability information indicating a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC includes: the capability information includes band combination information, and the band combination information indicates a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC. In this manner, the terminal device can report band-level or CC-level multicast capability in a band combination to improve the accuracy of the multicast capability report.

[0011] In a possible design, the capability information indicating multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC includes: the capability information includes an identifier of a first band combination list and a first feature set combination, the first band combination list includes first band information, the first band information includes identifiers of N bands supporting reception of the multicast service, N is an integer greater than 0, the first feature set combination includes at least one first parameter set corresponding to the first band combination list, and any one of the first parameter sets indicates multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands.

[0012] In the above scheme, identifiers of N bands that support reception of multicast services are listed in a band combination list, and the multicast service reception capabilities corresponding to each of the N bands in the band combination are indicated in the feature set combination, thereby improving multicast capability accuracy and helping the access network device schedule multicast services and / or unicast services for the terminal device.

[0013] In a possible design, the first band combination list further includes second band information, where the second band information includes identifiers of M bands supporting unicast services, where M is an integer greater than 0, and any of the first parameter sets further indicates unicast service reception capabilities corresponding to each of the M bands, or any of the first parameter sets further indicates communication service reception capabilities corresponding to each of the M bands, where the communication services include unicast services and multicast services. In the above design, the unicast service reception capabilities on the M bands are reported in the band combination, which can help the access network device obtain refined terminal device capabilities and help the access network device better provide multicast services and / or unicast services for the terminal devices.

[0014] In a possible design, the capability information indicating multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC includes: the capability information including identifiers of a second band combination list and a second feature set combination, the second band combination list including identifiers of N bands supporting reception of multicast services, N being an integer greater than 0, the second feature set combination including Q1 groups of parameters corresponding to the second band combination list, each group of parameters including Q2 second parameter sets, any second parameter set indicating multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, Q1 being an integer greater than 0 and Q2 being an integer greater than 0.

[0015] In the above design, the band combination list is expanded (i.e., a second band combination list) to indicate N bands that support reception of multicast services, and the multicast capabilities corresponding to the N bands are indicated in the feature set combination to improve multicast capability reporting accuracy, thereby enabling the access network device to obtain refined capability information. A possible implementation scheme helps the access network device schedule multicast or unicast services for the terminal device. Furthermore, the multicast and unicast capabilities corresponding to the N bands are distinguished, thereby enabling the unicast and multicast capabilities to indicate the communication capabilities of the terminal device in a combined manner in the band combination. Compared with a scheme in which all multicast and / or unicast capabilities supported in the band combination are sequentially indicated in an exhaustive manner, unnecessary capability information reporting can be reduced, thereby reducing signaling overhead.

[0016] In a possible design, the capability information further includes a third band combination list, which includes identifiers of M bands that support reception of unicast services, where M is an integer greater than 0; the second feature set combination further includes Q2 third parameter sets corresponding to the third band combination list, where any third parameter set indicates a unicast service reception capability corresponding to each of the M bands; and a second parameter set i among the Q2 second parameter sets corresponds to a first parameter set i among parameters of any of the Q1 groups, where i is an integer greater than 0 and not greater than Q2.

[0017] In the above design, multicast capability and unicast capability corresponding to N bands are distinguished, so that the unicast capability and multicast capability can indicate the communication capability of the terminal device in a combined manner in the band combination. Compared with the exhaustive method, the signaling overhead can be reduced. Furthermore, the existing mechanism for indicating the unicast capability part can be reused to the maximum extent, and the modification to the protocol can be reduced.

[0018] In a possible design, the capability information indicating a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC includes: the capability information includes identifiers of a second band combination list and Q1 third feature set combinations, the second band combination list including identifiers of N bands supporting reception of multicast services, N being an integer greater than 0, any third feature set combination including Q2 fourth parameter sets, any fourth parameter set indicating a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, Q1 being an integer greater than 0 and Q2 being an integer greater than 0.

[0019] In the above design, the band combination list is expanded (i.e., the second band combination list) to indicate N bands that support reception of multicast services, and the feature set combinations corresponding to the N bands that support reception of multicast services are expanded (i.e., Q1 third feature set combinations) to improve multicast capability reporting accuracy, thereby enabling access network devices to obtain refined capability information. A possible implementation scheme helps access network devices schedule multicast or unicast services for terminal devices.

[0020] Furthermore, multicast capabilities and unicast capabilities corresponding to the N bands are distinguished, so that the unicast capabilities and multicast capabilities can be combined to indicate the communication capabilities of a terminal device in a band combination. Compared with a method in which all multicast capabilities and / or unicast capabilities supported in a band combination are sequentially indicated in an exhaustive manner, unnecessary capability information reports can be reduced, thereby reducing signaling overhead.

[0021] In a possible design, the capability information further includes identifiers of a third band combination list and a fourth feature set combination, where the third band combination includes identifiers of M bands that support reception of unicast services, where M is an integer greater than 0, and the fourth feature set combination includes Q2 fifth parameter sets, where any of the fifth parameter sets indicates a unicast service reception capability corresponding to each of the M bands.

[0022] In the above design, by combining the identifier of the fourth feature set combination with the identifier of the third feature set combination, the capability report signaling overhead can be reduced. Furthermore, for indicating the unicast capability part, the existing mechanism can be reused to the maximum extent, and the protocol is slightly modified.

[0023] In a possible design, the capability information includes identifiers of a fourth band combination list and a fifth feature set combination, the fourth band combination list including identifiers of X bands supported by the terminal device, X being an integer greater than 0, the fifth feature set combination including at least one sixth parameter set, any sixth parameter set indicating communication parameters corresponding to each of the X bands, the X bands including N bands supporting reception of multicast services, the communication parameters corresponding to any one of the N bands indicating a multicast service reception capability corresponding to the band and / or a communication capability corresponding to a CC on the band, and if the CC supports reception of multicast services, the communication capability corresponding to the CC is the multicast service reception capability corresponding to the CC, and N is an integer greater than 0 but not greater than X.

[0024] In the above design, the communication parameters corresponding to the feature set index indicate the multicast service reception capability, thereby reducing the capability report signaling overhead. Furthermore, for indicating the unicast capability part, the existing mechanism can be reused to the maximum extent, and the protocol is slightly modified.

[0025] In a possible design, any sixth parameter set indicating communication parameters corresponding to each of the X bands includes: Any sixth parameter set includes an index of the communication parameters corresponding to each of the X bands; The index of the communication parameters for any one of the X bands satisfies the following: if the band supports reception of a multicast service, the index of the communication parameters corresponding to the band belongs to a first index set, and if the band does not support reception of a multicast service, the index of the communication parameters corresponding to the band belongs to a second index set.

[0026] In the above design, the index set is divided, so that an access network device can determine whether a band supports receiving a multicast service based on the index corresponding to the band, which can reduce signaling overhead and protocol complexity and further improve compatibility with previous versions of the protocol compared to a scheme in which a flag indicating whether receiving a multicast service is supported is explicitly carried in the communication parameters corresponding to the band.

[0027] In a possible design, the communication parameters corresponding to any one of the N bands indicating communication capabilities corresponding to CCs on the band include the following: the communication parameters corresponding to any one of the N bands include an index of a communication capability corresponding to a CC on the band, and the index of the communication capability corresponding to any CC on the band satisfies the following: if the CC supports reception of a multicast service, the index of the communication capability corresponding to the CC belongs to a third index set, and if the CC does not support reception of a multicast service, the index of the communication capability corresponding to the CC belongs to a fourth index set.

[0028] In the above design, the index set is divided, allowing an access network device to determine whether a CC supports receiving a multicast service based on the index corresponding to the CC. Compared with a scheme in which a flag indicating receiving a multicast service is explicitly carried in communication parameters corresponding to the CC, signaling overhead and protocol complexity can be reduced, and compatibility with devices supporting earlier versions of the protocol can be further improved.

[0029] In a possible design, the multicast service reception capability corresponding to a band includes at least one of the following: that the band supports reception of multicast services; or communication parameters for receiving multicast services on the band.

[0030] In a possible design, the multicast service reception capability corresponding to a CC indicates that the CC supports reception of a multicast service and / or includes communication information for receiving a multicast service on the CC, where the communication information is communication parameters for receiving a multicast service on the CC, or the communication information is a capability value of the CC, where the capability value is determined based on communication parameters for receiving a multicast service on the CC.

[0031] In a possible design, the communication parameters for receiving the multicast service include a highest modulation order supported during reception of the multicast service.

[0032] In a possible design, the communication parameters for receiving a multicast service further include whether simultaneous reception of unicast and multicast services is supported in the synchronous case, and / or whether simultaneous reception of unicast and multicast services is supported in the asynchronous case.

[0033] In a possible design, the method further includes sending indication information to the access network device, the indication information indicating a modulation order for a multicast service that the terminal device is receiving or expects to receive. In this design, the access network device may learn related information of the multicast service that the terminal device is receiving or expects to receive based on the indication information, thereby allowing the terminal device to better schedule multicast and / or unicast services.

[0034] In a possible design, before sending the instruction information to the access network device, the method further includes a step of receiving fourth information from the access network device, the fourth information instructing the access network device to report information regarding an inter-public land mobile network (PLMN) receiving multicast service, an inter-operator receiving multicast service, an inter-base station receiving multicast service, a non-serving cell receiving multicast service, or an inter-frequency receiving multicast service.

[0035] In a possible design, before sending the indication information to the access network device, the method further comprises: In the following cases, i.e. If the PLMN in the TMGI of the received multicast service does not match the PLMN contained in the system information block (SIB) 1 of the serving cell of the access network device, or If the PLMN contained in the SIB1 of the cell where the multicast service is received does not match the PLMN contained in the SIB1 of the serving cell of the access network device. The method further includes determining that the indication information needs to be reported when any of the following conditions is met:

[0036] In a possible design, the fourth information includes information about one or more PLMNs, and before sending the indication information to the access network device, the method further comprises: In the following cases, i.e. If the PLMN in the TMGI of the received multicast service differs from one or more PLMNs, or If the PLMN included in the SIB1 of the cell where the multicast service is received is different from one or more PLMNs The method further includes determining that the indication information needs to be reported when any of the following conditions is met:

[0037] In a possible design, before sending the indication information to the access network device, the method further comprises: In the following cases, i.e. If the frequency for receiving the multicast service is not a frequency included in the SIB21 of the serving cell of the access network device, and If the frequency for receiving a multicast service is different from the frequency list contained in the user service description (USD), determining that the indication needs to be reported when one or both of the following conditions are met:

[0038] In a possible design, the fourth information includes information about one or more frequencies, and before sending the indication information to the access network device, the method further comprises: The method further includes determining that the indication information needs to be reported when the following case is met: the frequency for receiving the multicast service is different from one or more frequencies.

[0039] In a possible design, before sending the indication information to the access network device, the method further includes receiving an SIB21 from the access network device.

[0040] In a possible design, the indication information further indicates at least one of the following information of the multicast service that the terminal device is receiving or expects to receive: frequency information, temporary mobile group identity (TMGI), and subcarrier spacing (SCS).

[0041] In a possible design, before the capability information is determined, the method further includes receiving capability report indication information from the access network device, where the capability report indication information instructs the terminal device to report its multicast service reception capability. In this design, the terminal device may report its multicast capability based on the instruction of the access network device, thereby enabling the terminal device to avoid unnecessary capability information reporting of the terminal device. Furthermore, the access network device can flexibly control the multicast service reception capability of the terminal device by using the indication information.

[0042] According to a second aspect, this application provides a communication method. The method may be performed by a second communication apparatus. The second communication apparatus may be a communication device, or may be a communication apparatus, such as a chip, that can support the communication device in implementing the functions required in the method. For example, the second communication apparatus 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. In the following description process, an example in which the second communication apparatus is a network device will be used for explanation.

[0043] The method includes a step of receiving capability information from a terminal device, the capability information indicating a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a CC, and a step of determining the capability of the terminal device based on the capability information.

[0044] In a possible design, the capability information indicating a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC includes: the capability information includes band combination information, and the band combination information indicates a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC. In this manner, the terminal device can report band-level or CC-level multicast capability in a band combination to improve the accuracy of the multicast capability report.

[0045] In a possible design, the capability information indicating multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC includes: the capability information includes an identifier of a first band combination list and a first feature set combination, the first band combination list includes first band information, the first band information includes identifiers of N bands supporting reception of the multicast service, N is an integer greater than 0, the first feature set combination includes at least one first parameter set corresponding to the first band combination list, and any one of the first parameter sets indicates multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands.

[0046] In a possible design, the first band combination list further includes second band information, where the second band information includes identifiers of M bands supporting unicast services, where M is an integer greater than 0, and any of the first parameter sets further indicates unicast service reception capabilities corresponding to each of the M bands, or any of the first parameter sets further indicates communication service reception capabilities corresponding to each of the M bands, where the communication services include unicast services and multicast services. In the above design, the unicast service reception capabilities on the M bands may be reported in the band combination to help the access network device accurately learn the capabilities of the terminal device and to help the access network device schedule multicast services or unicast services for the terminal device.

[0047] In a possible design, the capability information indicating multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC includes: the capability information including identifiers of a second band combination list and a second feature set combination, the second band combination list including identifiers of N bands supporting reception of multicast services, N being an integer greater than 0, the second feature set combination including Q1 groups of parameters corresponding to the second band combination list, each group of parameters including Q2 second parameter sets, any second parameter set indicating multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, Q1 being an integer greater than 0 and Q2 being an integer greater than 0.

[0048] In a possible design, the capability information further includes a third band combination list, which includes identifiers of M bands that support reception of unicast services, where M is an integer greater than 0; the second feature set combination further includes Q2 third parameter sets corresponding to the third band combination list, where any third parameter set indicates a unicast service reception capability corresponding to each of the M bands; and a second parameter set i among the Q2 second parameter sets corresponds to a first parameter set i among parameters of any of the Q1 groups, where i is an integer greater than 0 and not greater than Q2.

[0049] In the above design, multicast capability and unicast capability corresponding to N bands are distinguished, so that the unicast capability and multicast capability can be combined to indicate the communication capability of the terminal device in the band combination. Compared with the exhaustive approach, the signaling overhead can be reduced. Furthermore, for the unicast capability part, the existing mechanism can be reused to the maximum extent, and the protocol is slightly modified.

[0050] In a possible design, the capability information indicating a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC includes: the capability information includes identifiers of a second band combination list and Q1 third feature set combinations, the second band combination list including identifiers of N bands supporting reception of multicast services, N being an integer greater than 0, any third feature set combination including Q2 fourth parameter sets, any fourth parameter set indicating a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, Q1 being an integer greater than 0 and Q2 being an integer greater than 0.

[0051] In a possible design, the capability information further includes identifiers of a third band combination list and a fourth feature set combination, where the third band combination includes identifiers of M bands that support reception of unicast services, where M is an integer greater than 0, and the fourth feature set combination includes Q2 fifth parameter sets, where any of the fifth parameter sets indicates a unicast service reception capability corresponding to each of the M bands.

[0052] In a possible design, the capability information includes identifiers of a fourth band combination list and a fifth feature set combination, the fourth band combination list including identifiers of X bands supported by the terminal device, X being an integer greater than 0, the fifth feature set combination including at least one sixth parameter set, any sixth parameter set indicating communication parameters corresponding to each of the X bands, the X bands including N bands supporting reception of multicast services, the communication parameters corresponding to any one of the N bands indicating a multicast service reception capability corresponding to the band and / or a communication capability corresponding to a CC on the band, and if the CC supports reception of multicast services, the communication capability corresponding to the CC is the multicast service reception capability corresponding to the CC, and N is an integer greater than 0 but not greater than X.

[0053] In a possible design, any sixth parameter set indicating communication parameters corresponding to each of the X bands includes: Any sixth parameter set includes an index of the communication parameters corresponding to each of the X bands; The index of the communication parameters for any one of the X bands satisfies the following: if the band supports reception of a multicast service, the index of the communication parameters corresponding to the band belongs to a first index set, and if the band does not support reception of a multicast service, the index of the communication parameters corresponding to the band belongs to a second index set.

[0054] In the above design, the index set is divided, so that an access network device can determine whether a band supports receiving a multicast service based on the index corresponding to the band, which can reduce signaling overhead and protocol complexity and further improve compatibility with previous versions of the protocol compared to a scheme in which a flag indicating receiving a multicast service is explicitly carried in the communication parameters corresponding to the band.

[0055] In a possible design, the communication parameters corresponding to any one of the N bands indicating communication capabilities corresponding to CCs on the band include the following: the communication parameters corresponding to any one of the N bands include an index of a communication capability corresponding to a CC on the band, and the index of the communication capability corresponding to any CC on the band satisfies the following: if the CC supports reception of a multicast service, the index of the communication capability corresponding to the CC belongs to a third index set, and if the CC does not support reception of a multicast service, the index of the communication capability corresponding to the CC belongs to a fourth index set.

[0056] In the above design, the index set is divided, so that an access network device can determine whether a CC supports receiving a multicast service based on the index corresponding to the CC. Compared with a scheme in which a flag indicating receiving a multicast service is explicitly carried in communication parameters corresponding to the CC, signaling overhead and protocol complexity can be reduced, and compatibility with previous versions of the protocol can be further improved.

[0057] In a possible design, the multicast service reception capability corresponding to a band includes at least one of the following: that the band supports reception of multicast services; or communication parameters for receiving multicast services on the band.

[0058] In a possible design, the multicast service reception capability corresponding to a CC indicates that the CC supports reception of a multicast service and / or includes communication information for receiving a multicast service on the CC, where the communication information is communication parameters for receiving a multicast service on the CC, or the communication information is a capability value of the CC, where the capability value is determined based on communication parameters for receiving a multicast service on the CC.

[0059] In a possible design, the communication parameters for receiving the multicast service include a highest modulation order supported during reception of the multicast service.

[0060] In a possible design, the communication parameters for receiving a multicast service further include whether simultaneous reception of unicast and multicast services is supported in the synchronous case, and / or whether simultaneous reception of unicast and multicast services is supported in the asynchronous case.

[0061] In a possible design, the method further includes a step of receiving indication information from the terminal device, the indication information including a modulation order for a multicast service that the terminal device is receiving or expects to receive.

[0062] In a possible design, before receiving the instruction information from the terminal device, the method further includes a step of sending fourth information to the terminal device, the fourth information instructing the terminal device to report an inter-PLMN reception multicast service, an inter-operator reception multicast service, an inter-base station reception multicast service, a non-serving cell reception multicast service, or an inter-frequency reception multicast service.

[0063] In a possible design, before receiving the indication information from the terminal device, the method further includes sending an SIB21 to the terminal device.

[0064] In a possible design, the method further includes determining communication parameters for communicating with the terminal device based on the indication information. The above design assists the access network device in scheduling unicast services for the terminal device.

[0065] In a possible design, before receiving the capability information from the terminal device, the method further includes: sending capability report indication information to the terminal device, where the capability report indication information instructs the terminal device to report multicast service reception capability. Based on the above description, the terminal device may report multicast capability based on an instruction from the access network device, thereby avoiding unnecessary multicast capability reports.

[0066] In a possible design, the access network device may send a groupcast service to the terminal device based on the capability information.

[0067] In a possible design, after receiving the capability information, the access network device may configure an MBS radio bearer (MRB) for the groupcast service based on the capability information. For example, the access network device may configure the MBS radio bearer by using a radio resource control (RRC) configuration message. The access network device transmits the groupcast service after configuring the MRB.

[0068] In a possible design, the access network device may further receive indication information, which indicates information about the multicast service that the terminal device is receiving or expects to receive, such as one or more of information such as a session identifier (session ID), a subcarrier spacing (SCS), a bandwidth (BW), and a frequency used. The access network device may transmit a unicast service to the terminal device based on the capability information and indication information reported by the terminal device.

[0069] The beneficial effects of the method shown in the second embodiment and possible designs of the second embodiment are referred to the beneficial effects of the first embodiment and possible designs of the first embodiment.

[0070] According to a third aspect, this application provides a communication method, which may be performed by a terminal device or by a chip, circuit, or other component configured to realize the functionality of a terminal device, including determining first information and second information, the first information indicating that the terminal device is interested in a multicast service and the second information indicating the multicast service in which the terminal device is interested, and transmitting the first information and the second information, the first information being transmitted before security activation and the second information being transmitted after security activation.

[0071] In this embodiment of the present application, before security activation, the access network device is informed that the terminal device is interested in a multicast service, thereby enabling the access network device to configure resources used for the multicast service, such as common frequency resources (CFR), for the terminal device. Therefore, after resources used for unicast services are configured, the resources do not need to be reconfigured based on the multicast service. For example, after an initial bandwidth portion (initial BWP) is configured, the bandwidth of the initial BWP does not need to be configured as the bandwidth of the CFR based on the multicast service. This method can help reduce signaling overhead and ensure the continuity of the multicast service. Furthermore, information related to the multicast service in which the terminal device is interested is transmitted after security activation, thereby preventing specific information about the MBS from being transmitted in an insecure environment and improving communication security.

[0072] In a possible design, the terminal device satisfies the following conditions: the cell / access network device accessed by the terminal device provides a multicast service; the cell / access network device accessed by the terminal device is to provide a multicast service; The cell / access network device accessed by the terminal device supports the provision of multicast services; the terminal device is receiving or expects to receive a multicast service in the currently accessed cell / access network device; The multicast service that the terminal device is receiving or expects to receive is / is to be / is supported to be provided by the currently accessed cell / access network device; a cell currently accessed by the terminal device broadcasting an SIB used to provide multicast service information; A cell currently accessed by the terminal device broadcasts a first SIB, the first SIB carrying multicast control configuration information (MCCH); The bandwidth of the CFR of the multicast service provided by the cell currently accessed by the terminal device is different from the bandwidth of the initial BWP configured by using a system message; The bandwidth of the CFR of the multicast service provided by the cell currently accessed by the terminal device is greater than the bandwidth of the initial BWP configured by using a system message, or the terminal device receiving third information from the access network device, the third information indicating that the terminal device transmits the first information before security activation and transmits the second information after security activation; the first information may be transmitted before security activation and the second information may be transmitted after security activation when at least one of the following is satisfied. Optionally, the third information is carried in a broadcast message.

[0073] In a possible design, the second information includes a multicast service identifier, a multicast service identifier, or an Internet Protocol (IP) group address. In the above design, the multicast service in which the terminal device is interested is indicated after security activation, thereby preventing specific information of the MBS from being transmitted in an insecure environment and improving communication security.

[0074] In a possible design, the first information is a frequency of interest list and / or a priority of the multicast service. In the above design, the first information is implicitly indicated by using the frequency of interest list and / or the priority of the multicast service, thereby enabling signaling overhead to be reduced.

[0075] According to a fourth aspect, the present application provides a communication method, which may be performed by an access network device, or may be performed by a chip or a circuit, including: receiving first information and second information, the first information indicating that a terminal device is interested in a multicast service, and the second information indicating a multicast service in which the terminal device is interested, the first information being received before security activation, and the second information being received after security activation; and configuring an initial BWP for the terminal device based on the first information after receiving the first information, for example, configuring the bandwidth of the initial BWP as the bandwidth of a CFR.

[0076] In a possible design, the second information includes a multicast service identifier, a multicast service identifier, or an IP group address. In the above design, the multicast service in which the terminal device is interested is indicated after security activation, thereby preventing specific information of the MBS from being transmitted in an insecure environment and improving communication security.

[0077] In one possible design, the access network device transmits third information to the terminal device, the third information indicating that the terminal device transmits the first information before security activation and transmits the second information after security activation. Optionally, the third information is carried in a broadcast message.

[0078] In a possible design, the first information is a frequency of interest list and / or a priority of the multicast service. In the above design, the first information is implicitly indicated by using the frequency of interest list and / or the priority of the multicast service, thereby enabling signaling overhead to be reduced.

[0079] The beneficial effects of the method shown in the fourth embodiment and possible designs of the fourth embodiment are referred to the beneficial effects of the third embodiment and possible designs of the third embodiment.

[0080] According to a fifth aspect, the application provides a communication method, which may be performed by an access network device, or may be performed by a chip or a circuit. The method includes: a first access network device indicating a correspondence relationship to a second access network device, the correspondence relationship being a one-to-one correspondence relationship between one or more PLMN index values ​​and one or more PLMN values; the first access network device receiving indication information from a terminal device, the indication information indicating information about a multicast service that the terminal device is receiving or expects to receive, the indication information including at least one PLMN index value, the at least one PLMN index value belonging to the one or more PLMN index values; and the first access network device sending the indication information to the second access network device.

[0081] In a possible design, the indication information indicates at least one of the following information of the multicast service that the terminal device is receiving or expects to receive: frequency information, TMGI, SCS, or modulation order.

[0082] In a possible design, the first access network device indicating the correspondence to the second access network device includes:

[0083] The first access network device sends the PLMN identification information in the SIB1 to the second access network device, where the PLMN identification information indicates the correspondence.

[0084] In a possible design, the first access network device indicating the correspondence to the second access network device includes:

[0085] The first access network device sends an Xn interface setup message or an NG-RAN node configuration update message to the second access network device, where the Xn interface setup message or the NG-RAN node configuration update message includes information about at least one cell, and the information about a first cell in the at least one cell indicates at least one PLMN of the first cell and a PLMN index value corresponding to each PLMN.

[0086] In a possible design, the first access network device indicating the correspondence to the second access network device includes:

[0087] The first access network device sends an Xn interface setup message or an NG-RAN node configuration update message to the second access network device, where the Xn interface setup message or the NG-RAN node configuration update message includes information about at least one cell, and the information about cell n in the at least one cell indicates at least one PLMN and an offset of cell n, where the offset is the total number of PLMNs from cell 1 to cell (n-1) in the at least one cell, and n is an integer greater than 0.

[0088] According to a sixth aspect, the present application provides a communication method, which may be performed by an access network device, or may be performed by a chip or a circuit. The method includes: a second access network device obtains a correspondence relationship from a first access network device, the correspondence relationship being a one-to-one correspondence relationship between one or more PLMN index values ​​and one or more PLMN values; the second access network device receives indication information from the first access network device, the indication information indicating information about a multicast service that the terminal device is receiving or expects to receive, the indication information including at least one PLMN index value; and the second access network device determines a PLMN value corresponding to the at least one PLMN index value based on the correspondence relationship.

[0089] In a possible design, the indication information indicates at least one of the following information of the multicast service that the terminal device is receiving or expects to receive: frequency information, TMGI, SCS, or modulation order.

[0090] In a possible design, the second access network device obtaining the correspondence from the first access network device includes:

[0091] The second access network device receives the PLMN identity information in the SIB1 sent by the first access network device, and the PLMN identity information indicates the correspondence.

[0092] In a possible design, the second access network device obtaining the correspondence from the first access network device includes:

[0093] The second access network device receives an Xn interface setup message or an NG-RAN node configuration update message sent by the first access network device, where the Xn interface setup message or the NG-RAN node configuration update message includes information about at least one cell, and the information about a first cell in the at least one cell indicates at least one PLMN value of the first cell and a PLMN index value corresponding to each PLMN.

[0094] In a possible design, the second access network device obtaining the correspondence from the first access network device includes:

[0095] The second access network device receives an Xn interface setup message or an NG-RAN node configuration update message sent by the first access network device, wherein the Xn interface setup message or the NG-RAN node configuration update message includes information about at least one cell, and the information about cell n in the at least one cell indicates at least one PLMN value and offset of cell n, where the offset is the total number of PLMNs from cell 1 to cell (n-1) in the at least one cell, and n is an integer greater than 0.

[0096] According to a seventh aspect, the present application provides a communication method, which may be performed by an access network device, or may be performed by a chip or a circuit. The method includes: a first access network device receives first indication information from a terminal device, the first indication information indicating information about a multicast service that the terminal device is receiving or expects to receive, the first indication information including at least one PLMN index value; and the first access network device sends second indication information to a second access network device, the PLMN information in the second indication information being a PLMN value corresponding to the at least one PLMN index value.

[0097] In a possible design, the first indication information indicates at least one of the following information of the multicast service that the terminal device is receiving or expects to receive: frequency information, TMGI, SCS, or modulation order.

[0098] In a possible design, the second indication information is obtained by replacing at least one PLMN index value in the first indication information with a PLMN value corresponding to the at least one PLMN index value.

[0099] According to an eighth aspect, the present application provides a communication method. The method may be performed by a terminal device, or may be performed by a chip or a circuit. The method includes: the terminal device receives service information from an access network device, the service information including a first TMGI, the first TMGI including a first PLMN index value; the terminal device sends indication information to the access network device, the indication information indicating information about a multicast service that the terminal device is receiving or expects to receive, the indication information including a second TMGI, the second TMGI including a PLMN value corresponding to the first PLMN index value, and a service ID in the first TMGI and the second TMGI being the same.

[0100] In a possible design, the indication information indicates at least one of the following information of the multicast service that the terminal device is receiving or expects to receive: frequency information, TMGI, SCS, or modulation order.

[0101] In a possible design, the second TMGI is a TMGI carried in an application layer message received by the terminal device.

[0102] In another possible design, the second TMG is generated by the terminal device based on the first TMGI and a PLMN value corresponding to the first PLMN index value.

[0103] According to a ninth aspect, the present application further provides a communication device. The communication device implements any of the methods provided in the first, third, or eighth aspects. The communication device may be implemented by hardware, or by hardware executing corresponding software. The hardware or software may include one or more units or modules corresponding to the above functions.

[0104] In a possible design, the communication device includes a processor. The processor is configured to support the communication device in performing corresponding functions of the terminal device in the above method. The communication device may further include a memory. The memory is coupled to the processor and may store program instructions and data required for the communication device. Optionally, the communication device further includes an interface circuit. The interface circuit is configured to support communication between the communication device and a device such as an access network device.

[0105] In a possible design, the communication device includes corresponding functional modules configured separately to implement the steps of the above method. The functions may be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0106] In a possible design, the structure of the communication device includes a processing module and a communication module. The modules may perform corresponding functions in the above method examples. For details, please refer to the description in the method provided in the first aspect or the third aspect. The details will not be described again here.

[0107] According to a tenth aspect, the present application further provides a communication device. The communication device implements any of the methods provided in the second, fourth, fifth, sixth, or seventh aspects. The communication device may be implemented by hardware, or by hardware executing corresponding software. The hardware or software may include one or more units or modules corresponding to the above functions.

[0108] In a possible design, the communication device includes a processor configured to support the communication device in performing corresponding functions of the access network device in the above method. The communication device may further include a memory coupled to the processor and may store program instructions and data required by the communication device. Optionally, the communication device further includes an interface circuit configured to support communication between the communication device and a device such as a terminal device.

[0109] In a possible design, the communication device includes corresponding functional modules configured separately to implement the steps of the above method. The functions may be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0110] In a possible design, the structure of the communication device includes a processing module and a communication module. The modules may perform corresponding functions in the above method examples. For details, please refer to the description in the method provided in the second aspect or the fourth aspect. Details will not be described here.

[0111] According to an eleventh aspect, there is provided a communication device. The communication device includes a processor and an interface circuit. The interface circuit is configured to receive a signal from another communication device different from the communication device and transmit the signal to the processor, or transmit a signal from the processor to the other communication device different from the communication device. The processor is configured to implement the method of any one of the first, third, or eighth aspects and possible designs by using logic circuits or executing code instructions.

[0112] According to a twelfth aspect, there is provided a communication device. The communication device includes a processor and an interface circuit. The interface circuit is configured to receive a signal from another communication device different from the communication device and transmit the signal to the processor, or transmit a signal from the processor to another communication device different from the communication device. The processor is configured to implement the method of any one of the second, fourth, fifth, sixth, or seventh aspects and possible designs by using logic circuits or executing code instructions.

[0113] According to a thirteenth aspect, there is provided a computer-readable storage medium storing a computer program or instructions, which, when executed by a processor, implements the method of any one of the first to eighth aspects and possible designs.

[0114] According to a fourteenth aspect, there is provided a computer program product storing instructions which, when executed by a processor, effect the method of any one of the first to eighth aspects and possible designs.

[0115] According to a fifteenth aspect, there is provided a chip system. The chip system includes a processor and may further include a memory, and may implement the method in any one of the first to eighth aspects and possible designs. The chip system may include a chip, or may include a chip and other discrete components.

[0116] According to a sixteenth aspect, there is provided a communications system. The system includes an apparatus (e.g., a terminal device) according to the first aspect and an apparatus (e.g., an access network device) according to the second aspect. Alternatively, the system includes an apparatus (e.g., a terminal device) according to the third aspect and an apparatus (e.g., an access network device) according to the fourth aspect. Alternatively, the system includes an apparatus (e.g., a first access network device) according to the fifth aspect and an apparatus (e.g., a second access network device) according to the sixth aspect. Alternatively, the system includes an apparatus (e.g., a first access network device) according to the seventh aspect and a second access network device. Alternatively, the system includes an apparatus (e.g., a terminal device) according to the eighth aspect and an access network device. [Brief explanation of the drawings]

[0117] [Figure 1] 1 is a schematic diagram of a multicast service according to an embodiment of the present application; [Figure 2] FIG. 1 is a schematic diagram of a multicast scenario according to an embodiment of the present application; [Figure 3] FIG. 1 is a schematic diagram of a feature set combination according to an embodiment of the present application. [Figure 4] FIG. 2 is a schematic diagram of a structure of capability information according to an embodiment of the present application; [Figure 5] 1 is a schematic diagram of the architecture of a communication system according to an embodiment of the present application; [Figure 6] FIG. 2 is a schematic diagram of the architecture of another communication system according to an embodiment of the present application; [Figure 7]1 is a schematic flowchart of a communication method according to an embodiment of the present application; [Figure 8] 1 is a schematic flowchart of transmitting a groupcast service according to an embodiment of the present application; [Figure 9] FIG. 2 is a schematic diagram of a structure of capability information according to an embodiment of the present application; [Figure 10] 1 is a schematic flowchart of a communication method according to an embodiment of the present application; [Figure 11] 1 is a schematic diagram of the structure of a communication device according to an embodiment of this application; [Figure 12] 1 is a schematic diagram of the structure of a communication device according to an embodiment of this application; DETAILED DESCRIPTION OF THE INVENTION

[0118] In order to make the objectives, technical solutions and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. A specific operation method in a method embodiment may also be applied to an apparatus embodiment or a system embodiment.

[0119] In the following description, some terms in the embodiments of this application will be described to help those skilled in the art have a better understanding.

[0120] (1) MBS: An MBS is a service that is simultaneously transmitted to multiple terminal devices, such as a live broadcast service, a public security service, or a batch software update service. A multicast service may include one or more of a groupcast service and a broadcast service. A multicast service may also be called a groupcast service, a broadcast service, a groupcast / broadcast service, a groupcast / multicast service, or a multicast / broadcast service. An MBS originates from a data server. First, the data server transmits MBS data to a core network device, then the core network device transmits the MBS data to an access network device, and finally, the access network device transmits the MBS data to at least one terminal device that receives the MBS. When the core network device transmits MBS data to an access network device, the MBS data is transmitted on a common transmission channel, i.e., an MBS session. However, when the access network device transmits MBS data to a terminal device, there are two transmission methods. The first method may be a point-to-multipoint (PTM) transmission method, and the second method may be a point-to-point (PTP) transmission method, which are shown in FIG.

[0121] In the embodiments of this application, an MBS may also be referred to as an "MBS service," an "MBS broadcast service," an "MBS session," an "MBS broadcast business," an "MBS business," and the like.

[0122] As shown in Figure 2, one terminal device supports receiving an MBS service from one access network device and receiving a unicast service from another access network device. Alternatively, one terminal device may receive an MBS service and a unicast service from one access network device.

[0123] It should be noted that MBS is merely an exemplary name for a multicast service, and the name of the multicast service may be different in different communication standards. For example, a multicast service in long term evolution (LTE) may be called a multimedia broadcast multicast service (MBMS), and a multicast service in new radio (NR) may be called an MBS. In future communication developments, multicast services may also be called by other names, which are not particularly limited in this application and are hereinafter collectively referred to as multicast services.

[0124] (2) Receive only mode (ROM) is a mode in which a terminal device is permitted to access a public land mobile network (PLMN) that provides multicast broadcast services and receive only multicast broadcast services without registering with the PLMN.

[0125] (3) Terminal device capability report

[0126] The network device obtains the capability information of the terminal device in a capability query process. In the capability query process, the network device sends indication information to the terminal device, which indicates the capability parameters that need to be reported by the terminal device. The terminal device uploads corresponding capability information according to the indication of the indication information.

[0127] Currently, there are terminal devices with multi-radio access technology (RAT) capability, which is the ability of a terminal device to operate simultaneously in multiple RATs. A typical expression of multi-RAT capability is the Evolved Universal Terrestrial Radio Access New Radio Dual Connectivity (E-UTRA-NR dual connectivity, EN) mode. EN-DC is a scheme in which LTE and NR operate together in dual connectivity mode. LTE base station is the master node. Specifically, one terminal device is connected to both an LTE network device and an NR network device, and the two network devices simultaneously serve the terminal device. Multi-RAT capability is also requested as a capability type when capability is requested.

[0128] Capability structure of terminal devices in NR: Due to different hardware or software versions, different terminal devices support different capabilities in one RAT. In order to better serve terminal devices, the network needs to learn the capabilities of the terminal devices and then configure an appropriate operation mode for the terminal devices.

[0129] The capability structure of a terminal device in NR includes band combination list and band information.

[0130] The band combination information includes a band list and a feature set combination.

[0131] The Band List contains the band combinations supported by the terminal device and indicates the bands specifically included in the band combination, for example, band 1 + band 2 + band 3. Obviously, reporting can be performed using this structure even if only one band is supported.

[0132] A Feature Set Combination indicates the capabilities supported by a terminal device in a band combination. A Feature Set Combination is a set containing multiple feature sets. Each Feature Set Combination contains matrix elements of multiple feature set indexes (feature set IDs). Each feature set ID is associated with one band. For example, Figure 3 shows a Feature Set Combination associated with a band combination including band A, band B, and band C. Each row corresponds to the uplink feature set ID and downlink feature set ID used for band A, band B, and band C, respectively. Different rows indicate different Feature Set Combinations supported by the UE in the band combination. The first row is used as an example. The matrix elements of different feature sets supported by the UE in a combination including band A, band B, and band C are (0,0), (2,4), and (1,2), respectively. It can be understood that the matrix element (0,0) indicates that the uplink feature set index and downlink feature set index used in band A are both 0, the matrix element (2,4) indicates that the uplink feature set index and downlink feature set index used in band B are 2 and 4, respectively, and the rest can be inferred by analogy.

[0133] A feature set ID corresponds to a group of communication parameters and indicates capabilities supported by a terminal device on a band, such as the number of carriers, carrier bandwidth, and multiple-input multiple-output (MIMO) technology capabilities. The communication parameters corresponding to a feature set ID may include capabilities supported by a terminal device on the entire band and capabilities supported on each CC of the band (feature set per CC).

[0134] The band information may include a band list, which includes bands supported by the terminal device and capabilities supported by the terminal device on each band.

[0135] For example, the capability structure of the terminal device may be as shown in FIG.

[0136] It should be understood that the capability structure of the terminal device may further include other information not shown, for example, terminal device level capability information, which is not particularly limited here.

[0137] (4) Terminal device capability query process

[0138] Unicast communication is performed between the network device and the terminal device. Therefore, the network device usually obtains the capabilities of the terminal device in a capability query process, so that the network device transmits and receives data in a unicast manner based on the capabilities of the terminal device. In the capability query process, the network device may send capability query information to the terminal device to request the capabilities of the terminal device.

[0139] The capability query information typically includes an information element, which includes multiple fields indicating the capabilities of the terminal device that need to be requested. The information element of the capability query information sent by the network device may be a filter function, such as a UE-Capability Request Filter Common. The filter function may include: Used to filter the required capabilities of the end device The filtered capability of the terminal device is the capability of the terminal device that meets the requirements of the network device. Therefore, the network device may obtain the capability of the terminal device reported by the terminal device through the instruction of the network device by using the filter function.

[0140] (5) A terminal device includes a device that provides a voice and / or data connection to a user. Specifically, a terminal device includes a device that provides a voice connection to a user, a device that provides a data connection to a user, or a device that provides a voice and data connection to a user. For example, a terminal device may include a handheld device with wireless connectivity or a processing device connected to a wireless modem. A terminal device communicates with a core network through a radio access network (RAN) and may exchange voice or data with the RAN, or may exchange voice and data with the RAN. A terminal device may include a UE, a wireless terminal device, a mobile terminal device, a device-to-device communication (D2D) terminal device, a vehicle-to-everything (V2X) terminal device, a machine-to-machine / machine type communication (M2M / MTC) terminal device, an internet of things (IoT) terminal device, a subscriber unit, a subscriber station, a mobile station, a remote station, an access point (AP), a remote terminal, an access terminal, a user terminal, a user agent, a user device, etc. For example, a terminal device may include a mobile phone (also called a "cellular" phone), a computer having a mobile terminal device, or a portable, pocket-sized, handheld, or computer-embedded mobile device.For example, a terminal device may be a device such as a personal communication service (PCS) telephone, a cordless telephone set, a session initiation protocol (SIP) telephone, a wireless local loop (WLL) station, or a personal digital assistant (PDA). Terminal devices may also include limited devices, such as devices with low power consumption, limited storage capabilities, or limited computing capabilities. For example, terminal devices may include information sensing devices such as barcodes, radio frequency identification (RFID), sensors, global positioning systems (GPS), or laser scanners.

[0141] By way of example and not limitation, in the embodiments of this application, the terminal device may alternatively be a wearable device. A wearable device may also be referred to as a wearable intelligent device, an intelligent wearable device, etc., and is a general term for wearable devices developed by applying wearable technology to the intelligent design of everyday wear, such as glasses, gloves, watches, clothes, and shoes. A wearable device is a portable device that is directly attached to or incorporated into a user's clothing or accessories. A wearable device is not just a hardware device, but achieves powerful functions through software support, data exchange, and cloud interaction. Generalized wearable intelligent devices include full-function large devices, such as smart watches or smart glasses, that can achieve full or partial functions independently of a smartphone, and devices that focus on only one type of application function and need to operate together with other devices, such as smartphones, such as various smart bands, smart helmets, or smart jewelry for monitoring physical signs.

[0142] In the embodiment of this application, the terminal device may further include a relay. Alternatively, it may be understood that any device capable of performing data communication with a base station may be considered a terminal device.

[0143] In the embodiments of this application, the apparatus configured to realize the functions of the terminal device may be the terminal device itself, or may be an apparatus within the terminal device and capable of supporting the terminal device in realizing the functions, such as a part or component having a communication function, or a chip system. The apparatus may be mounted on the terminal device. In the embodiments of this application, the chip system may include a chip, or may include a chip and other discrete components. In the technical solutions provided in the embodiments of this application, Terminal Device An example in which the apparatus configured to realize the functions is a terminal device is used to describe the technical solutions provided in the embodiments of this application.

[0144] (6) The network device may be, for example, an access network (AN) device, such as a base station (e.g., an access point), which is within the access network and communicates with terminal devices over the air interface through one or more cells. For example, the network device may include an evolved Node B (eNB or e-Node B) in an LTE system or a long-term evolution-advanced (LTE-A) system, a next-generation Node B (gNB) in a fifth-generation (5G) NR system (also referred to as an NR system), or a central unit (CU) and / or a distributed unit (DU) in a cloud radio access network (Cloud RAN) system. This is not limited to the embodiments of this application. For example, the network device may be a CU, a DU, or both a CU and a DU in a Cloud RAN system.

[0145] The network devices may further include core network devices, which include, for example, an access and mobility management function (AMF). Since the embodiments of this application mainly relate to access networks, the network devices are access network devices in the following description unless otherwise specified.

[0146] In the embodiments of this application, the apparatus configured to realize the functions of the network device may be a network device, or may be an apparatus, such as a chip system, that can support the network device in realizing the functions. The apparatus may be installed in the network device. In the technical solutions provided in the embodiments of this application, an example in which the apparatus configured to realize the functions of the network device is a network device is used to describe the technical solutions provided in the embodiments of this application.

[0147] In the embodiments of this application, "at least one" means one or more, and "plurality" means two or more. The term "and / or" describes an association relationship between related objects and indicates that three relationships may exist. For example, A and / or B may represent the following cases: only A is present, both A and B are present, and only B is present, where A and B may be singular or plural. The character " / " typically indicates an "or" relationship between related objects. At least one of the following items (moieties) or similar expressions refers to any combination of these items, including a singular item (moiety) or any combination of multiple items (moieties). For example, at least one of a, b, or c may refer to a, b, c, a and b, a and c, b and c, or a, b and c, where a, b, and c may be singular or plural.

[0148] Unless otherwise specified, ordinal terms such as "first" and "second" referred to in the embodiments of this application are used to distinguish between multiple objects and are not intended to limit the size, content, order, time sequence, priority, importance, etc. of the multiple objects. For example, a first parameter and a second parameter are used simply to distinguish between different parameters and do not indicate different content, different values, different priorities, different importance, etc. of the two parameters.

[0149] The above describes some noun concepts used in the embodiments of this application. The following describes the technical features in the embodiments of this application.

[0150] In a mobile communication system, communication between a terminal device and a network device is performed over a band. Different terminal devices may support different bands or different band combinations, and the terminal devices may have different baseband capabilities over different bands or band combinations. The baseband capabilities may include the carrier bandwidth, the number of carriers, the number of supported channel state indicator (CSI) processes, the number of multiple-input multiple-output (MIMO) layers, etc. The terminal device needs to report information about the supported bands or band combinations and baseband capabilities to the network device. The network device performs resource configuration for a service based on the capabilities of the terminal device.

[0151] In some scenarios, a terminal device may also receive a broadcast-multicast service when performing a unicast operation. In this case, the unicast service and the broadcast-multicast service share the baseband capability of the terminal device. Therefore, when a terminal device performs a unicast operation, the terminal device needs to report its capability to receive a multicast broadcast to a network device, so that the network device can configure a multicast broadcast service based on the capability information reported by the terminal device. Currently, in LTE, the way a terminal device reports its multicast broadcast reception capability is to report mbms-MaxBW in the capability information, where mbms-MaxBW indicates the maximum bandwidth supported for MBS reception.

[0152] Currently, multicast capability information designed in LTE is at the UE level and does not distinguish between bands and carriers. Only the maximum bandwidth used for MBS can be reported. Existing NR multicast services can only be supported on the terminal's band. If LTE multicast capabilities are reused, the multicast capabilities of the NR UE cannot be accurately reported.

[0153] Based on this, the embodiments of this application provide a communication method and an apparatus for solving the problem of low accuracy of multicast capability reporting of terminal devices. The method and the apparatus are based on the same inventive concept. Because the method and the apparatus have similar problem-solving principles, the implementation manners of the apparatus and the method refer to each other and no repeated description is provided.

[0154] The communication methods provided in this application may be applied to various communication systems, such as the Internet of Things (IoT), narrow band internet of things (NB-IoT), long term evolution (LTE), fifth generation (5G) communication systems, hybrid architectures of LTE and 5G, 5G new radio (NR) systems, 6G systems, or new communication systems emerging in future communication developments. The communication system in this application may alternatively be a machine-to-machine (M2M) network or other network.

[0155] 5 shows a communication system according to an embodiment of the present application. The communication system may include a terminal device and an access network device, and may further include a core network device. In the communication system, the terminal device may receive a multicast service from the access network device.

[0156] 6 shows a communication system according to an embodiment of this application. The communication system may include a terminal device and two access network devices, namely, access network device 1 and access network device 2. In the communication system, the terminal device may receive a unicast service from access network device 1 and a multicast service from access network device 2. The two services may share the baseband capability of the terminal device.

[0157] Optionally, access network device 1 and access network device 2 may be connected to different core network devices. For example, the communication system may further include core network device 1 and core network device 2. As shown in Figure 6, access network device 1 is connected to core network device 1, and access network device 2 is connected to core network device 2.

[0158] Alternatively, access network device 1 and access network device 2 may be connected to the same core network device, for example, the communication system includes core network device 3, and both access network device 1 and access network device 2 are connected to core network device 3.

[0159] 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 any limitations on the technical solutions provided in the embodiments of this application. Those skilled in the art may recognize that with the evolution of network architectures and the emergence of new service scenarios, the technical solutions provided in the embodiments of this application can also be applied to similar technical problems.

[0160] The following describes the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application.

[0161] FIG. 7 is a schematic flowchart of a communication method according to an embodiment of the present application.

[0162] S801: A terminal device determines capability information.

[0163] The capability information indicates a multicast service reception capability corresponding to the band and / or a multicast service reception capability corresponding to the CC. For example, the multicast service may include a groupcast service and a broadcast service.

[0164] The capability information indicating a multicast service reception capability corresponding to a band may be understood as follows: The capability information includes a multicast service reception capability at the band level (per band). The capability information indicating a multicast service reception capability corresponding to a CC may be understood as follows: The capability information includes a multicast service reception capability at the CC level (per CC).

[0165] In the embodiments of this application, "multicast service reception capability" may also be replaced with "ability to receive MBS service", "MBS capability", "groupcast capability", "broadcast capability", "ROM capability", "free to air (FTA) capability", etc. In the embodiments of this application, "multicast service reception capability" is used as an example for explanation.

[0166] A specific manner in which the capability information indicates the multicast service reception capability corresponding to the band and / or the multicast service reception capability corresponding to the CC will be described in detail below.

[0167] It should be noted that step S801 may be an optional step, specifically, the terminal device may not reflect the process of determining the capability information.

[0168] S802: The terminal device sends capability information to the access network device. Correspondingly, the access network device receives capability information from the terminal device.

[0169] Optionally, before step S802 or before S801, the access network device may send capability report indication information to the terminal device, where the capability report indication information instructs the terminal device to report its multicast service reception capability.

[0170] Specifically, the capability reporting indication information instructing the terminal device to report multicast service reception capability specifically includes the following: The capability reporting indication information instructs the terminal device to report capabilities corresponding to all bands supporting multicast services, or capabilities corresponding to all bands supporting multicast services and included in the current PLMN or the specified PLMN. For example, the capability reporting indication information may indicate whether to report capabilities by using one or more values ​​of one or more bits. Alternatively, the capability reporting indication information may indicate whether to report capabilities depending on whether one or more bits are carried. Alternatively, a field in the capability reporting indication information indicates whether to report capabilities by using true / false.

[0171] Alternatively, the capability report indication information instructing the terminal device to report multicast service reception capabilities specifically includes: The capability report indication information may carry one or more indexes or identifiers of one or more bands, and the capability report indication information instructs the terminal device to report one or more multicast service reception capabilities on the one or more bands.

[0172] S803: The access network device determines the capability of the terminal device based on the capability information.

[0173] In an implementation manner, the access network device may transmit the multicast service to the terminal device based on the capability information.

[0174] For example, in the communication system shown in FIG. 5, the terminal device may transmit capability information to the access network device, and the access network device may transmit a groupcast service to the terminal device based on the capability information. Specifically, after the terminal device transmits the capability information to the access network device, the access network device may configure an MRB for the groupcast service based on the capability information, for example, by using an RRC configuration message. As shown in FIG. 8, the access network device transmits the groupcast service after configuring the MRB.

[0175] In another implementation, the access network device may send unicast services to the terminal device based on the capability information.

[0176] For example, in the communication system shown in FIG. 6, the terminal device may send capability information to the access network device 1, and the access network device 1 may send a unicast service to the terminal device based on the capability information.

[0177] In a specific implementation manner, in addition to sending capability information to the access network device, the terminal device may also send indication information to the access network device. The indication information indicates information about the multicast service that the terminal device is receiving or expects to receive, such as a session identifier, or information such as the SCS, BW, or frequency used. The access network device may select a group of capability information sets supported by the terminal device based on the capability information and indication information reported by the terminal device, thereby enabling the access network device to transmit unicast services to the terminal device without affecting the terminal device's reception of multicast services.

[0178] Optionally, the terminal device may further transmit indication information to the access network device. The indication information may indicate a modulation order for a multicast service that is being received or is expected to be received. For example, an MBS interest indication (MII) indicates a modulation order for a multicast service that is being received or is expected to be received. Optionally, the indication information may further indicate at least one of the following information of the multicast service that the terminal device is receiving or is expected to receive: frequency information (such as bandwidth and / or frequency), TMGI, and SCS.

[0179] The name (or type) of the indication information is not limited in this application. In the following description, MII may alternatively be replaced with other information indicating the service that the UE is interested in, such as user assistance information (UAI). For ease of explanation, the following uses an example in which the indication information is MII for explanation.

[0180] It should be noted that the triggering method, transmission method and content of the MII may be realized independently without relying on the method in Fig. 8. When the triggering method, transmission method and content of the MII are realized independently, the information indicated by the MII may include the content indicated by the instruction information, may not include the content indicated by the instruction information, or may include some information in the instruction information.

[0181] In the implementation, the terminal device may obtain a modulation order for a multicast service that is being received or expected to be received from MBS traffic channel (MTCH) configuration information. Optionally, in this implementation, before sending the indication information, the terminal device may receive system information from the access network device, where the system information includes MCCH configuration information, and receive the MCCH based on the MCCH configuration information, where the MCCH includes the MTCH configuration information.

[0182] In another implementation, the terminal device may alternatively obtain the modulation order for the multicast service being received or expected to be received from downlink control information (DCI). Specifically, the terminal device may report the obtained modulation order in real time, or may report the maximum modulation order after obtaining the modulation order n times.

[0183] Furthermore, after reporting the modulation order for the multicast service being received or expected to be received, the terminal device may further update the modulation order, for example, after obtaining the updated modulation order for the multicast service being received or expected to be received from the DCI, the terminal device transmits the updated modulation order to the access network device.

[0184] For example, in the communication system shown in Figure 6, the terminal device may send capability information to the access network device 1, and the terminal device may send an MII to the access network device 1. The MII indicates information about multicast services that the terminal device is receiving or expects to receive from the access network device 2. The access network device 1 may send unicast services to the terminal device based on the capability information and MII reported by the terminal device.

[0185] In LTE, a terminal device receives mbms-ROM-ServiceIndication in SIB2 of a primary cell / primary serving cell (PCell) to trigger the terminal device to report MII (i.e., indication information). However, in NR or future communications, such information may not exist. As a result, the terminal device cannot be triggered to report MII. Based on this, this application provides three methods for triggering a terminal device to report MII.

[0186] In a first method, the access network device transmits fourth information to the terminal device to indicate whether to report the MII, and the fourth information may indicate to report an inter-PLMN reception multicast service, an inter-operator reception multicast service, an inter-base station reception multicast service, a non-serving cell reception multicast service, or an inter-frequency reception multicast service.

[0187] In this method, after receiving the fourth information, the terminal device may determine whether the MII needs to be reported. Four determination methods are described below. It should be understood that the four methods may be implemented separately, or may be implemented by combining any two, three, or four methods.

[0188] Determination method 1: When any of the following cases is met, the terminal device may determine that the MII needs to be reported:

[0189] Case 1: The PLMN in the TMGI of the received multicast service does not match the PLMN information contained in the SIB1 of the serving cell of the access network device.

[0190] Case 2: The PLMN included in the SIB1 of the cell where the multicast service is received does not match the PLMN included in the SIB1 of the serving cell of the access network device.

[0191] "Mismatch" in decision method 1 may be understood as there being at least a difference between the PLMN in the TMGI (or SIB1) of the received multicast service and the PLMN included in the SIB1 of the serving cell of the access network device.

[0192] In this implementation, the fourth information may be one or more bits.

[0193] Determination method 2: When any of the following cases is met, the terminal device may determine that the MII needs to be reported:

[0194] Case 3: The fourth information includes one or more PLMNs, and the PLMN in the TMGI of the received multicast service is different from one or more PLMNs.

[0195] Case 4: The fourth information includes one or more PLMNs, and the PLMN included in the SIB1 of the cell where the multicast service is received is different from the one or more PLMNs.

[0196] "Different" in decision method 2 may be understood as there being at least a difference between the PLMN in the TMGI (or SIB1) of the received multicast service and any one of the one or more PLMNs.

[0197] Determination method 3: When one or more of the following cases are met, the terminal device may determine that the MII needs to be reported:

[0198] Case 5: The frequency for receiving the multicast service is not a frequency included in the SIB21 of the serving cell of the access network device.

[0199] Case 6: The frequency for receiving the multicast service is different from the frequency in the frequency list contained in the USD.

[0200] Determination method 4: When the following conditions are met, the terminal device may determine that the MII needs to be reported:

[0201] Case 7: The indication information includes information about one or more frequencies, and the frequency for receiving the multicast service is different from the one or more frequencies.

[0202] In the above four determination methods, the access network device may be access network device 1 in the scenario shown in FIG.

[0203] In a second method, the protocol may specify that the serving cell of the access network device needs to trigger the terminal device to report the MII by sending SIB21. The access network device may be access network device 1 in the scenario shown in Figure 6.

[0204] In a third method, the terminal device may determine that the MII needs to be reported.

[0205] For example, when an inter-PLMN or inter-operator condition is met, the terminal device may decide to report an inter-PLMN received multicast service or an inter-operator received multicast service.

[0206] For details, please refer to the above determination method 1 or determination method 2. The details will not be described again here.

[0207] In another example, when an inter-frequency condition is met, the terminal device may decide to report an inter-frequency receiving multicast service.

[0208] For details, please refer to the above Decision Method 3 or Decision Method 4. The details will not be described again here.

[0209] The above describes three methods for triggering a terminal device to report an MII. The contents of the MII reported by the terminal device are described below with reference to the above three methods.

[0210] Based on the first method, the terminal device may determine, based on the fourth information, that the MII needs to be reported, and may determine, based on the fourth information, frequency information (e.g., frequency and / or bandwidth) / TMGI / SCS / modulation order included in the MII.

[0211] Based on the third method, the terminal device may determine that the MII needs to be reported based on inter-operator / inter-PLMN / inter-frequency / non-serving cell, and may determine the frequency information (e.g., frequency and / or bandwidth) / TMGI / SCS / modulation order to be included in the MII based on the operator / PLMN / frequency.

[0212] Based on the second method, the terminal device may determine based on SIB21 that the MII needs to be reported, and may determine the frequency information (e.g., frequency and / or bandwidth) / TMGI / SCS / modulation order to be included in the MII based on the operator / PLMN / frequency.

[0213] In this embodiment of the present application, the terminal device may indicate multicast capability at the band (also called frequency band) level and / or CC level by using capability information, thereby improving multicast capability reporting accuracy and enabling the access network device to obtain refined capability information. In a possible implementation, the access network device may provide multicast services and / or unicast services based on the refined capability information, for example, may configure or select communication parameters for the multicast services and / or unicast services based on the refined capability information.

[0214] Hereinafter, a method for indicating a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a CC will be described with reference to the structure of the capability information.

[0215] In an exemplary description, the band combination information in the capability information may indicate a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a CC, or the band information in the capability information may indicate a multicast service reception capability corresponding to a band. Below, an example in which the band combination information indicates a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a CC and an example in which the band information indicates a multicast service reception capability corresponding to a band will be separately described.

[0216] The band combination information may indicate the multicast service reception capability corresponding to the band and / or the multicast service reception capability corresponding to the CC in the following four ways.

[0217] Scheme 1: From the above terminology introduction (3), it can be learned that the capability information includes a Band Combination List, which includes a Band List and a Feature Set Combination. In this scheme, the bands that support receiving multicast services may be listed in the Band List in the Band Combination List, and the Feature Set Combination corresponding to the Band List indicates the multicast service reception capability on the bands that support receiving multicast services.

[0218] Example 1: The capability information includes identifiers of a first band combination list and a first feature set combination. The first band combination list includes first band information, which includes identifiers of N bands supporting reception of a multicast service, where N is an integer greater than 0. The first feature set combination includes at least one first parameter set corresponding to the first band combination list, where any one of the first parameter sets indicates a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands. For example, N may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. In an implementation, the network device may indicate the number N of bands reported by the terminal device that support the multicast service, or the maximum number N of bands reported by the terminal device that support the multicast service.

[0219] Optionally, the first band combination list may further include second band information, where the second band information includes identifiers of M bands supporting unicast services, where M is an integer greater than 0. Any of the first parameter sets further indicates unicast service reception capabilities corresponding to each of the M bands, or any of the first parameter sets further indicates communication service reception capabilities corresponding to each of the M bands, where the communication services include unicast services and multicast services.

[0220] In Example 1, the first band combination list lists identifiers of M bands for which the terminal device supports unicast services and identifiers of N bands for which the terminal device supports multicast services. Here, the bands are distinguished based on the communication services supported on the bands. If the terminal device supports reception of multicast services on a band, the first band information includes an identifier of the band. If the terminal device supports reception of unicast services on a band, the second band information includes an identifier of the band. If a band supports reception of both multicast services and unicast services, the identifier of the band is included in the first band information and the second band information. In other words, the identifier of the band appears twice in the first band combination list.

[0221] In one example, in this method, the capability information may have a structure in which the capability information includes a first band combination list and an identifier of a first feature set combination. The first band combination list includes identifiers of N bands supporting reception of multicast services and identifiers of M bands supporting reception of unicast services. If a band supports reception of both multicast and unicast services, the identifier of the band appears twice in the first band combination list. The first feature set combination includes matrix elements of multiple feature set indexes (feature set IDs), each associated with one band. Each row of the feature set index may be considered a first parameter set, and each row of the feature set index, i.e., each first parameter set, indicates a feature set combination supported by the terminal device in the band combination. Each row of the feature set index of the first feature set combination, i.e., each first parameter set, may include feature set indexes corresponding to the N bands and may further include feature set indexes corresponding to the M bands.

[0222] A feature set index corresponding to each of the N bands corresponds to a group of communication parameters and indicates a multicast service reception capability of a terminal device on the band. A feature set index corresponding to each of the M bands corresponds to a group of communication parameters and indicates a unicast service reception capability of a terminal device on the band, or indicates a communication service reception capability of a terminal device on the band. Communication services include unicast services and multicast services, and may further include other services. This is not particularly limited here.

[0223] Optionally, the feature set index corresponding to the M bands may include two parts: an uplink feature set index and a downlink feature set index. The uplink feature set index may correspond to a group of communication parameters, which may include band-level communication parameters and CC-level communication parameters. In the group of communication parameters, the band-level communication parameters indicate uplink transmission capabilities on the band. The CC-level communication parameters indicate uplink transmission capabilities on the CC.

[0224] The downlink feature set index may correspond to a group of communication parameters, and the group of communication parameters may include band-level communication parameters and CC-level communication parameters. In the group of communication parameters, the band-level communication parameters indicate a capability to receive unicast services on the band. The CC-level communication parameters indicate a capability to receive unicast services on the band. Alternatively, in the group of communication parameters, the band-level communication parameters indicate a capability to receive communication services on the band. The CC-level communication parameters indicate a capability to receive communication services on the CC.

[0225] The feature set indexes corresponding to the N bands may include a downlink feature set index. The downlink feature set index may correspond to a group of communication parameters, and the group of communication parameters may include band-level communication parameters and CC-level communication parameters. In the group of communication parameters, the band-level communication parameters indicate a multicast service reception capability on the band. The CC-level communication parameters indicate a multicast service reception capability on the band.

[0226] For example, the band level communication parameters included in the communication parameters corresponding to the uplink feature set indexes of the M bands, the band level communication parameters included in the communication parameters corresponding to the downlink feature set indexes of the M bands, or the band level communication parameters included in the communication parameters corresponding to the downlink feature set indexes of the N bands may include at least one of the following types of communication parameters: SCS, BW, number of multiple-input multiple-output (MIMO) layers, modulation order, etc.

[0227] Optionally, the band level communication parameters included in the communication parameters corresponding to the downlink feature set indexes of the N bands further include a flag indicating that reception of multicast services is supported.

[0228] The CC level communication parameters included in the communication parameters corresponding to the uplink feature set indexes of the M bands, the CC level communication parameters included in the communication parameters corresponding to the downlink feature set indexes of the M bands, or the CC level communication parameters included in the communication parameters corresponding to the downlink feature set indexes of the N bands may include at least one of the following types of communication parameters: SCS corresponding to the CC, BW corresponding to the CC, number of MIMO layers corresponding to the CC, ModulationOrder corresponding to the CC, etc.

[0229] Alternatively, the CC-level communication parameters included in the communication parameters corresponding to the downlink feature set indexes of the N bands may be a capability value, and the capability value may be determined based on the above parameters such as the SCS. In one implementation, the capability value may be a weighted sum of the SCS, BW, the number of MIMO layers, and Modulation Order. In another implementation, the capability value may be a product of the SCS, BW, the number of MIMO layers, and Modulation Order. Obviously, the capability value may alternatively be determined by other calculation methods, which are not particularly limited herein.

[0230] Optionally, the CC level communication parameters included in the communication parameters corresponding to the downlink feature set indexes of the N bands further include a flag indicating that reception of multicast services is supported.

[0231] The following describes Example 1 by using a concrete example.

[0232] Assume that a terminal device supports receiving unicast services on band A and band B, and supports receiving multicast services on band B and band C. The structure of the capability information may be as shown in Table 1. [Table 1]

[0233] Example 1 will be described with reference to Table 1 above. Table 1 shows band combination information in the capability information, i.e., a Band Combination List. Band list 1 is a first band combination list. The first band combination list may indicate identifiers of N bands that support reception of multicast services and identifiers of M bands that support unicast services. Table 1 uses an example in which bands B and C support multicast services, and bands A and B support unicast services.

[0234] featureSetCombinationID1 is an identifier of a first feature set combination, which includes at least one first parameter set corresponding to a first band combination list. Each pair of square brackets represents one first parameter set and indicates capabilities supported by the terminal device in the band combination. Each pair of parentheses in the same pair of square brackets sequentially identifies a feature set corresponding to each band in the band combination list. For example, in each pair of square brackets, the first pair of parentheses identifies a feature set corresponding to band A, the second pair of parentheses identifies a feature set corresponding to band B, the third pair of parentheses identifies a feature set corresponding to band B and used for receiving multicast services, and the fourth pair of parentheses identifies a feature set corresponding to band C and used for receiving multicast services.

[0235] The element in each pair of parentheses is a feature set index, where fsul represents a feature set corresponding to the uplink, fsdl represents a feature set corresponding to the downlink, and n1, n2, etc. are index values. Specifically, fsul_n1 represents the communication parameters of the feature set corresponding to the uplink corresponding to the index value n1, and fsdl_n1 represents the communication parameters of the feature set corresponding to the downlink corresponding to the index value n1. The contents indicated by each feature set index correspond to the same structure. Using fsdl_n1 as an example, as shown in Table 1, fsdl_n1 corresponds to band-level communication parameters, i.e., Per Band parameters, and CC-level communication parameters, i.e., Per CC parameters. The Per CC parameters specifically include feature set identifiers corresponding to CCs, for example, feature set identifier fsdlperCC_n1 corresponding to CC1 and feature set identifier fsdlperCC_n2 corresponding to CC2.

[0236] The feature set identifier corresponding to a CC may indicate a communication parameter corresponding to the CC, for example, the SCS, BW, number of MIMO layers or Modulation Order corresponding to the CC, or in another example, a capability value corresponding to the CC.

[0237] It should be understood that the structure of the contents indicated by the other Feature Set Indexes included in the first Feature Set Combination is similar to the structure of fsdl_n1. For details, please refer to the related description of fsdl_n1. The details will not be described again here.

[0238] In Example 1, one or more bits in the capability query may be used to trigger the terminal device to report a capability combination of band B and band C for receiving a multicast service, or one or more bits in the capability query may be used to trigger the terminal device to report a capability for receiving a multicast service on band B (band B may be a band in the same PLMN or a band in another PLMN), or the band filtering list of the MBS in the capability query may include band B and band C, triggering the terminal device to report a capability combination of band B and band C for receiving a multicast service.

[0239] Example 2: The capability information includes identifiers of a second band combination list and a second feature set combination, the second band combination list including identifiers of N bands that support reception of multicast services, where N is an integer greater than 0, the second feature set combination including Q1 groups of parameters corresponding to the second band combination list, where each group of parameters includes Q2 second parameter sets, where any of the second parameter sets indicates a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, where Q1 is an integer greater than 0 and Q2 is an integer greater than 0.

[0240] Optionally, the capability information further includes a third band combination list, the third band combination list including identifiers of M bands supporting reception of unicast services, where M is an integer greater than 0; the second feature set combination further includes Q2 third parameter sets corresponding to the third band combination list, where any third parameter set indicates a unicast service reception capability corresponding to each of the M bands; and second parameter set i among the Q2 second parameter sets corresponds to first parameter set i among parameters in any one of the Q1 groups, where i is an integer greater than 0 but not greater than Q2. It may be understood that a combination of second parameter set i among the Q2 second parameter sets and first parameter set i in any one of the Q1 parameter groups may indicate a feature set combination supported by the terminal device in the band combination, and the band combination is a band combination obtained by combining the second band combination list and the third band combination list.

[0241] In Example 2, the second band combination list lists identifiers of N bands for which the terminal device supports reception of multicast services, and the third band combination list lists identifiers of M bands for which the terminal device supports reception of unicast services. Here, the bands are distinguished based on the communication services supported on the bands. If the terminal device supports reception of multicast services on a band, the second band combination list includes an identifier of the band. If the terminal device supports reception of unicast services on a band, the third band combination list includes an identifier of the band. If the band supports reception of both multicast services and unicast services, the identifier of the band is included in the second band combination list and the third band combination list.

[0242] In one example, in this method, the capability information may have a structure in which the capability information includes a second band combination list, a third band combination list, and identifiers of second feature set combinations. The second band combination list includes identifiers of N bands that support reception of multicast services, and the third band combination list includes identifiers of M bands that support reception of unicast services. If a band supports reception of multicast services and unicast services, the identifier of the band is included in the second band combination list and the third band combination list.

[0243] The second feature set combination includes a first matrix and at least one extended matrix. The first matrix includes matrix elements of a plurality of feature set indexes (feature set IDs), each of which is associated with one of the M bands. Each row of the feature set indexes may be considered a third parameter set. Each row of the feature set indexes of the first matrix, i.e., each third parameter set, includes a feature set index corresponding to the M bands. The feature set index corresponding to each of the M bands corresponds to a group of communication parameters and indicates a unicast service reception capability of a terminal device on the band or a communication service reception capability of a terminal device on the band. The communication services include a unicast service and a multicast service.

[0244] Each extension matrix includes matrix elements of multiple feature set indexes (feature set IDs), and each feature set index is associated with one of the N bands. Each row of the feature set indexes of each extension matrix may be considered a second parameter set. Each row of the feature set indexes of each extension matrix, i.e., each second parameter set, includes feature set indexes corresponding to the N bands. The feature set index corresponding to each of the N bands corresponds to a group of communication parameters and indicates the multicast service reception capability of a terminal device on the band.

[0245] The feature set index row i of the first matrix may be combined with the feature set index row i of the extended matrix. The feature set combination obtained through the combination may represent a feature set combination supported by the terminal device in a band combination. The band combination is a band combination obtained by combining the second band combination list and the third band combination list.

[0246] For an explanation of the meaning of the Feature Set Index corresponding to M bands and the Feature Set Index corresponding to N bands, refer to the explanation of the Feature Set Index corresponding to M bands and the Feature Set Index corresponding to N bands in Example 1. The details will not be explained again here.

[0247] The following describes Example 2 by using a concrete example.

[0248] Assume that a terminal device supports receiving unicast services on band A and band B, and multicast services on band B and band C. The structure of the capability information may be as shown in Table 2. [Table 2]

[0249] Example 2 will be described with reference to Table 2 above. Table 2 shows band combination information in the capability information, i.e., a Band Combination List. Band list extend is a second band combination list, which may indicate identifiers of N bands that support reception of multicast services. Table 2 uses an example in which band B and band C support multicast services. Band list 1 is a third band combination list, which may indicate identifiers of M bands that support reception of unicast services. Table 2 uses an example in which band A and band B support unicast services.

[0250] FeatureSetCombinationID 1 is an identifier of the second feature set combination, which includes Q2 third parameter sets corresponding to Band list 1. In Table 2, Q2=3 is used as an example. The second feature set combination includes a first matrix, which includes Q2=3 third parameter sets corresponding to Band list 1. Each pair of square brackets in the first matrix represents one third parameter set, and each pair of parentheses in the same pair of square brackets sequentially identifies a feature set corresponding to each band in Band list 1. For example, in each pair of square brackets, the first pair of parentheses identifies a feature set corresponding to band A, and the second pair of parentheses identifies a feature set corresponding to band B.

[0251] The second feature set combination further includes Q1 groups of parameters corresponding to the band list extend, and each group of parameters includes Q2 second parameter sets. In Table 2, Q1=3 is used as an example. The second feature set combination includes Q1=3 extension matrices, and each extension matrix is ​​a group of parameters corresponding to the band list extend and includes Q2=3 second parameter sets. Each pair of square brackets in each extension matrix represents one second parameter set, and each pair of parentheses in the same pair of square brackets sequentially identifies a feature set for receiving multicast services corresponding to each band in the band list extend. For example, in each pair of square brackets, the first pair of parentheses identifies a feature set for receiving multicast services corresponding to band B, and the second pair of parentheses identifies a feature set for receiving multicast services corresponding to band C.

[0252] The pairs of brackets in the first matrix correspond one-to-one to the pairs of brackets in each extension matrix based on the row in which the brackets are located. Extension matrix 1 is used as an example, and the first row in the first matrix, i.e., the first pair of brackets, corresponds to the first row in the extension matrix, i.e., the first pair of brackets. The brackets with a corresponding relationship may be combined to indicate the feature set combinations supported by the terminal device in a band combination. The band combination is a band combination obtained by combining Band list extend and Band list 1.

[0253] In Table 2, for details regarding the parentheses contained within the brackets, the elements contained within the parentheses, and the meanings indicated by the elements, please refer to the relevant explanations in Table 1. The details will not be repeated here.

[0254] In Table 2, the number of rows in the first matrix is ​​the same as the number of rows in the extended matrix, i.e., the number of third parameter sets included in the first matrix is ​​the same as the number of second parameter sets included in the extended matrix.

[0255] In Example 2, by combining the first matrix and the extended matrix, the signaling overhead for capability reporting can be reduced. Furthermore, for the unicast capability part, the existing mechanism can be reused to the maximum extent, and the protocol is slightly modified.

[0256] In Example 2, one or more bits in the capability query may be used to trigger the terminal device to report a capability combination of band B and band C for receiving a multicast service, or one or more bits in the capability query may be used to trigger the terminal device to report a capability for receiving a multicast service on band B (band B may be a band in the same PLMN or a band in another PLMN), or the band filtering list of the MBS in the capability query may include band B and band C, triggering the terminal device to report a capability combination of band B and band C for receiving a multicast service.

[0257] Example 3: The capability information includes identifiers of a second band combination list and Q1 third feature set combinations, where the second band combination list includes identifiers of N bands that support reception of multicast services, and N is an integer greater than 0. Any of the third feature set combinations includes Q2 fourth parameter sets, and any of the fourth parameter sets indicates a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, and Q1 is an integer greater than 0 and Q2 is an integer greater than 0.

[0258] In an optional manner, the capability information may list identifiers of the Q1 third feature set combinations, or the capability information may include extended information, and the extended information may correspond to the identifiers of the Q1 third feature set combinations.

[0259] Optionally, the capability information further includes identifiers of a third band combination list and a fourth feature set combination, where the third band combination includes identifiers of M bands supporting reception of unicast services, where M is an integer greater than 0, and the fourth feature set combination includes Q2 fifth parameter sets, where any fifth parameter set indicates a unicast service reception capability corresponding to each of the M bands. The fifth parameter set i in the fourth feature set combination corresponds to each fourth parameter combination in the third feature set combination i, where i is an integer greater than 0 but not greater than Q2. It may be understood that a combination of the fifth parameter set i in the fourth feature set combination and any fourth parameter set combination in the third feature set combination i may indicate a feature set combination supported by the terminal device in the band combination, where the band combination is a band combination obtained by combining the second band combination list and the third band combination list.

[0260] In Example 3, the second band combination list lists identifiers of N bands for which the terminal device supports reception of multicast services, and the third band combination list lists identifiers of M bands for which the terminal device supports reception of unicast services. Here, the bands are distinguished based on the communication services supported on the bands. If the terminal device supports reception of multicast services on a band, the second band combination list includes an identifier of the band. If the terminal device supports reception of unicast services on a band, the third band combination list includes an identifier of the band. If the band supports reception of both multicast services and unicast services, the identifier of the band is included in the second band combination list and the third band combination list.

[0261] In one example, in this method, the capability information may have a structure in which the capability information includes a second band combination list, a third band combination list, identifiers of Q1 third feature set combinations, and identifiers of a fourth feature set combination. The second band combination list includes identifiers of N bands that support reception of multicast services, and the third band combination list includes identifiers of M bands that support reception of unicast services. If a band supports reception of multicast services and unicast services, the identifier of the band is included in the second band combination list and the third band combination list.

[0262] Each third feature set combination includes a plurality of feature set index matrix elements, and each feature set index is associated with one of the N bands. Each row of the feature set index for each third feature set combination may be considered a fifth parameter set. Each row of the feature set index for each third feature set combination, i.e., each fifth parameter set, includes feature set indexes corresponding to the N bands. The feature set index corresponding to each of the N bands corresponds to a group of communication parameters and indicates the multicast service reception capability of a terminal device on the band.

[0263] The fourth feature set combination includes matrix elements of a plurality of feature set indexes, each of which is associated with one of the M bands. Each row of the feature set indexes may be considered a fourth parameter set. Each row of the feature set indexes of the fourth feature set combination, i.e., each fourth parameter set, includes feature set indexes corresponding to the M bands. The feature set index corresponding to each of the M bands corresponds to a group of communication parameters and indicates a unicast service reception capability of a terminal device on the band, or indicates a communication service reception capability of a terminal device on the band. The communication service includes a unicast service and a multicast service.

[0264] A combination of row i of the feature set index in the fourth feature set combination with any row of the feature set index in the third feature set combination may indicate a feature set combination supported by the terminal device in a band combination, which is a band combination obtained by combining the second band combination list and the third band combination list.

[0265] For an explanation of the meaning of the Feature Set Index corresponding to M bands and the Feature Set Index corresponding to N bands, refer to the explanation of the Feature Set Index corresponding to M bands and the Feature Set Index corresponding to N bands in Example 1. The details will not be explained again here.

[0266] The following describes Example 3 by using a concrete example.

[0267] Assume that a terminal device supports receiving unicast services on band A and band B, and supports receiving multicast services on band B and band C. The structure of the capability information may be as shown in Table 3a. [Table 3a] TIFF0007768485000004.tif93170

[0268] The number of rows included in the feature set combination corresponding to featureSetCombinationID 1 may be understood as the number of parameter sets included in the feature set combination corresponding to featureSetCombinationID 1.

[0269] The number of rows included in the feature set combination corresponding to featureSetCombination_extend ID 1 may be understood as the number of parameter sets included in the feature set combination corresponding to featureSetCombination_extend ID 1.

[0270] The number of rows included in the feature set combination corresponding to featureSetCombination_extend ID 2 may be understood as the number of parameter sets included in the feature set combination corresponding to featureSetCombination_extend ID 1.

[0271] The number of rows included in the feature set combination corresponding to featureSetCombination_extend ID 3 may be understood as the number of parameter sets included in the feature set combination corresponding to featureSetCombination_extend ID 1.

[0272] Example 3 will be described with reference to Table 3a above. Table 3a shows band combination information in the capability information, i.e., a Band Combination List. Band list extend is a second band combination list, which may indicate identifiers of N bands that support reception of multicast services. Table 3a uses an example in which band B and band C support multicast services. Band list 1 is a third band combination list, which may indicate identifiers of M bands that support reception of unicast services. Table 3a uses an example in which band A and band B support unicast services.

[0273] FeatureSetCombinationID 1 is an identifier of the fourth feature set combination, which includes Q2 third parameter sets corresponding to Band list 1. In Table 3a, Q2=3 is used as an example. The fourth feature set combination includes Q2=3 third parameter sets corresponding to Band list 1, where each pair of square brackets represents one third parameter set, and each pair of parentheses in the same pair of square brackets sequentially identifies a feature set corresponding to each band in Band list 1. For example, in each pair of square brackets, the first pair of parentheses identifies a feature set corresponding to band A, and the second pair of parentheses identifies a feature set corresponding to band B.

[0274] The featureSetCombination_extend ID list includes identifiers of Q1=3 third feature set combinations. Each third feature set combination includes Q2 second parameter sets. In Table 3a, Q1=3 is used as an example, and each third feature set combination includes Q2=3 fourth parameter sets. Each pair of square brackets in each third feature set combination represents one fourth parameter set, and each pair of parentheses in the same pair of square brackets sequentially identifies a feature set for receiving a multicast service corresponding to each band in the Band list extend. For example, in each pair of square brackets, the first pair of parentheses identifies a feature set for receiving a multicast service corresponding to band B, and the second pair of parentheses identifies a feature set for receiving a multicast service corresponding to band C.

[0275] The first pair of brackets in the fourth feature set combination may be combined with each pair of brackets in the first third feature set combination, i.e., the third feature set combination corresponding to index 1 in the featureSetCombination_extend ID list. The second pair of brackets in the fourth feature set combination may be combined with each pair of brackets in the second third feature set combination, i.e., the third feature set combination corresponding to index 2 in the featureSetCombination_extend ID list. The third pair of brackets in the fourth feature set combination may be combined with each pair of brackets in the third third feature set combination, i.e., the third feature set combination corresponding to index 3 in the featureSetCombination_extend ID list.

[0276] The third feature set combination corresponding to index 1 in the featureSetCombination_extend ID list is used as an example. The first pair of brackets in the fourth feature set combination and the first pair of brackets in the third feature set combination corresponding to index 1 in the featureSetCombination_extend ID list are combined to indicate a feature set combination supported by the terminal device in the band combination. The band combination is a band combination obtained by combining the Band list extend and Band list 1. The first pair of brackets in the fourth feature set combination and the second pair of brackets in the third feature set combination corresponding to index 1 in the featureSetCombination_extend ID list are combined to indicate a feature set combination supported by the terminal device in the band combination. The band combination is a band combination obtained by combining the Band list extend and Band list 1. The rest can be inferred by analogy.

[0277] In Table 3a, for details regarding the parentheses contained within the brackets, the elements contained within the parentheses, and the meanings indicated by the elements, please refer to the relevant explanations in Table 1. The details will not be repeated here.

[0278] In another example, in this method, the capability information may have a structure in which the capability information includes identifiers of a second band combination list, a third band combination list, and a fourth feature set combination. The second band combination list includes identifiers of N bands that support reception of multicast services, and the third band combination list includes identifiers of M bands that support reception of unicast services. If a band supports reception of multicast services and unicast services, the identifier of the band is included in the second band combination list and the third band combination list.

[0279] The fourth feature set combination includes matrix elements of a plurality of feature set indexes, each of which is associated with one of the M bands. Each row of the feature set indexes may be considered a fourth parameter set. Each row of the feature set indexes of the fourth feature set combination, i.e., each fourth parameter set, includes feature set indexes corresponding to the M bands. The feature set index corresponding to each of the M bands corresponds to a group of communication parameters and indicates a unicast service reception capability of a terminal device on the band, or indicates a communication service reception capability of a terminal device on the band. The communication service includes a unicast service and a multicast service.

[0280] The fourth Feature Set combination may further indicate the third Feature Set combination that corresponds to (or is called for) each row of the Feature Set Index.

[0281] Each third feature set combination includes a plurality of feature set index matrix elements, and each feature set index is associated with one of the N bands. Each row of the feature set index for each third feature set combination may be considered a fifth parameter set. Each row of the feature set index for each third feature set combination, i.e., each fifth parameter set, includes feature set indexes corresponding to the N bands. The feature set index corresponding to each of the N bands corresponds to a group of communication parameters and indicates the multicast service reception capability of a terminal device on the band.

[0282] A combination of one row of the feature set index and any row of the feature set index in the corresponding third feature set combination may indicate a feature set combination supported by the terminal device in a band combination, where the band combination is a band combination obtained by combining the second band combination list and the third band combination list.

[0283] For an explanation of the meaning of the Feature Set Index corresponding to M bands and the Feature Set Index corresponding to N bands, refer to the explanation of the Feature Set Index corresponding to M bands and the Feature Set Index corresponding to N bands in Example 1. The details will not be explained again here.

[0284] The following describes Example 3 by using a concrete example.

[0285] Assume that a terminal device supports receiving unicast services on band A and band B, and multicast services on band B and band C. The structure of the capability information may be as shown in Table 3b. [Table 3b] TIFF0007768485000006.tif81170

[0286] The number of rows included in the feature set combination corresponding to featureSetCombinationID 1 may be understood as the number of parameter sets included in the feature set combination corresponding to featureSetCombinationID 1.

[0287] The number of rows included in the feature set combination corresponding to featureSetCombination_extend ID 1 may be understood as the number of parameter sets included in the feature set combination corresponding to featureSetCombination_extend ID 1.

[0288] The number of rows included in the feature set combination corresponding to featureSetCombination_extend ID 2 may be understood as the number of parameter sets included in the feature set combination corresponding to featureSetCombination_extend ID 2.

[0289] The number of rows included in the feature set combination corresponding to featureSetCombination_extend ID 3 may be understood as the number of parameter sets included in the feature set combination corresponding to featureSetCombination_extend ID 3.

[0290] Example 3 will be described with reference to Table 3b above. Table 3b shows band combination information in the capability information, i.e., a Band Combination List. Band list extend is a second band combination list, which may indicate identifiers of N bands that support reception of multicast services. Table 3b uses an example in which band B and band C support multicast services. Band list 1 is a third band combination list, which may indicate identifiers of M bands that support reception of unicast services. Table 3b uses an example in which band A and band B support unicast services.

[0291] featureSetCombinationID 1 is an identifier of the fourth feature set combination, which includes Q2 third parameter sets corresponding to Band list 1. In Table 3b, Q2=3 is used as an example. The fourth feature set combination includes Q2=3 third parameter sets corresponding to Band list 1, where each pair of square brackets represents one third parameter set, and each pair of parentheses in the same pair of square brackets sequentially identifies a feature set corresponding to each band in Band list 1. For example, in each pair of square brackets, the first pair of parentheses identifies a unicast service reception capability corresponding to band A, and the second pair of parentheses identifies a unicast service reception capability corresponding to band B. In another example, the first pair of parentheses in each pair of square brackets identifies a communication service reception capability corresponding to band A. Since the terminal device supports reception of unicast services on band A, the communication service reception capability corresponding to band A may include a unicast service reception capability. The second pair of parentheses identifies the communication service reception capability corresponding to band B. Because the terminal device supports reception of unicast and multicast services on band B, the communication service reception capability corresponding to band B may include unicast service reception capability and multicast service reception capability.

[0292] Each pair of square brackets further includes a third feature set combination corresponding to the pair of square brackets. For example, the first pair of square brackets includes featureSetCombination_extend ID 1, indicating that the pair of square brackets corresponds to the third feature set combination corresponding to featureSetCombination_extend ID 1. Each third feature set combination includes Q2=3 fourth parameter sets. Each pair of square brackets in each third feature set combination represents one fourth parameter set, and each pair of parentheses in the same pair of square brackets sequentially identifies a feature set corresponding to each band in the Band list extend. For example, in each pair of square brackets, the first pair of parentheses identifies a multicast service reception capability corresponding to band B, and the second pair of parentheses identifies a multicast service reception capability corresponding to band C.

[0293] The first pair of brackets in the fourth feature set combination may be combined with each pair of brackets in the first third feature set combination, i.e., the third feature set combination corresponding to featureSetCombination_extend ID 1. The second pair of brackets in the fourth feature set combination may be combined with each pair of brackets in the second third feature set combination, i.e., the third feature set combination corresponding to featureSetCombination_extend ID 2. The third pair of brackets in the fourth feature set combination may be combined with each pair of brackets in the third third feature set combination, i.e., the third feature set combination corresponding to featureSetCombination_extend ID 3.

[0294] The third feature set combination corresponding to featureSetCombination_extend ID 1 is used as an example. The first pair of brackets in the fourth feature set combination and the first pair of brackets in the third feature set combination corresponding to featureSetCombination_extend ID 1 are combined to indicate a feature set combination supported by the terminal device in the band combination. The band combination is a band combination obtained by combining Band list extend and Band list 1. The first pair of brackets in the fourth feature set combination and the second pair of brackets in the third feature set combination corresponding to featureSetCombination_extend ID 1 are combined to indicate a feature set combination supported by the terminal device in the band combination. The band combination is a band combination obtained by combining Band list extend and Band list 1. The rest can be inferred by analogy.

[0295] In Table 3b, for details regarding the parentheses contained within the brackets, the elements contained within the parentheses, and the meanings indicated by the elements, please refer to the relevant explanations in Table 1. The details will not be repeated here.

[0296] In Example 3, by combining the identifier of the fourth feature set combination with the identifier of the third feature set combination, the capability report signaling overhead can be reduced. Furthermore, for the unicast capability part, the existing mechanism can be reused to the maximum extent, and the protocol is slightly modified.

[0297] Example 4: The capability information includes identifiers of a fourth band combination list and a fifth feature set combination, the fourth band combination list including identifiers of X bands supported by the terminal device, where X is an integer greater than 0, the fifth feature set combination including at least one sixth parameter set, where any sixth parameter set indicates communication parameters corresponding to each of the X bands, where the X bands include N bands that support reception of multicast services, the communication parameters corresponding to any one of the N bands indicate a multicast service reception capability corresponding to the band and / or a communication capability corresponding to a CC on the band, and if the CC supports reception of multicast services, the communication capability corresponding to the CC is the multicast service reception capability corresponding to the CC, and N is an integer greater than 0 but not greater than X.

[0298] In Example 4, the fourth band combination list lists identifiers of X bands supported by the terminal device, regardless of whether the terminal device supports multicast. Provided that the terminal device supports communication on one band, the fourth band combination list includes the identifier of the band. If the band supports both reception of multicast services and reception of unicast services, the identifier of the band appears once in the fourth band combination list.

[0299] In one example, in this method, the capability information may have a structure in which the capability information includes a fourth band combination list and an identifier of a fifth feature set combination. The fourth band combination list includes identifiers of X bands supported by the terminal device. If a band supports reception of multicast and unicast services, the identifier of the band appears once in the fourth band combination list. The fifth feature set combination includes matrix elements of multiple feature set indexes (feature set IDs), each feature set index being associated with one band. Each row of the feature set index may be considered a sixth parameter set, and each row of the feature set index, i.e., each sixth parameter set, indicates a feature set combination supported by the terminal device in the band combination. Each row of the feature set index of the fifth feature set combination, i.e., each sixth parameter set, may include feature set indexes corresponding to the X bands.

[0300] A feature set index corresponding to each of the X bands corresponds to a group of communication parameters and indicates the communication capabilities of the terminal device on the band. Optionally, the feature set index corresponding to each of the X bands may include two parts, i.e., an uplink feature set index and a downlink feature set index. The uplink feature set index may correspond to a group of communication parameters, and the group of communication parameters may include band-level communication parameters and CC-level communication parameters. In the group of communication parameters, the band-level communication parameters indicate uplink transmission capabilities on the band. The CC-level communication parameters indicate uplink transmission capabilities on the band.

[0301] The downlink feature set index may correspond to a group of communication parameters, and the group of communication parameters may include band-level communication parameters and CC-level communication parameters. In the group of communication parameters, the band-level communication parameters indicate a communication service reception capability on the band. The CC-level communication parameters indicate a communication service reception capability on the CC.

[0302] In an exemplary description, if a terminal device does not support uplink transmission on one band, the uplink feature set index corresponding to the band may be a first feature set index, and the first feature set index indicates that the terminal device does not support uplink transmission.

[0303] If a terminal device supports receiving a multicast service on a band, the communication parameters corresponding to the downlink feature set index corresponding to the band may indicate the multicast service reception capability of the terminal device on the band, and specifically may include at least one of the following: band-level communication parameters for receiving a multicast service and CC-level communication parameters for receiving a multicast service.

[0304] The band level communication parameters for receiving a multicast service may include at least one of the following types of communication parameters: a flag indicating that reception of a multicast service is supported, SCS, BW, number of MIMO layers, ModulationOrder, etc.

[0305] The CC level communication parameters for receiving a multicast service may include at least one of the following types of communication parameters: a flag indicating that reception of a multicast service is supported, SCS, BW, number of MIMO layers, ModulationOrder, etc.

[0306] The following describes Example 4 by using a concrete example.

[0307] Assume that a terminal device supports receiving unicast services on band A and band B, and supports receiving multicast services on band B and band C. The structure of the capability information may be as shown in Table 4. [Table 4]

[0308] Example 4 will be described with reference to Table 4 above. Table 4 shows band combination information in the capability information, i.e., a Band Combination List. Band list 1 is a fourth band combination list, which may indicate identifiers of X bands supported by a terminal device. It should be noted that Band list 1 does not distinguish whether a band supports multicast services.

[0309] featureSetCombinationID 1 is an identifier of a fifth feature set combination, which includes at least one sixth parameter set corresponding to Band list 1. Each pair of square brackets represents one sixth parameter set and indicates the capabilities supported by the terminal device in the band combination. Each pair of parentheses in the same pair of square brackets sequentially identifies a feature set corresponding to each band in the band combination list. For example, in each pair of square brackets, the first pair of parentheses identifies the feature set corresponding to band A, the second pair of parentheses identifies the feature set corresponding to band B, and the third pair of parentheses identifies the feature set corresponding to band C.

[0310] The elements in each pair of parentheses are feature set indexes, where fsul represents the feature set corresponding to the uplink, fsdl represents the feature set corresponding to the downlink, and n1, n2, etc. are index values. Specifically, fsul_n1 represents that the feature set corresponding to the uplink is the communication parameters corresponding to the index value n1, and fsdl_n1 represents that the feature set corresponding to the downlink is the communication parameters corresponding to the index value n1. The contents indicated by each feature set index correspond to the same structure.

[0311] Using fsdl_n1 as an example, fsdl_n1 corresponds to a band-level communication parameter, i.e., Per band parameter, and a CC-level communication parameter, i.e., Per CC parameter, as shown in Table 1. The Per CC parameter specifically includes a feature set identifier corresponding to the CC, for example, feature set identifier fsdlperCC_n1 corresponding to CC1 and feature set identifier fsdlperCC_n2 corresponding to CC2. If the band supports reception of a multicast service, the Per band parameter may include a communication parameter for receiving the multicast service.

[0312] The feature set identifier corresponding to the CC may indicate communication parameters corresponding to the CC, such as the SCS, BW, number of MIMO layers, or Modulation Order corresponding to the CC. If the CC supports reception of a multicast service, the communication parameters indicated by the feature set identifier corresponding to the CC may include communication parameters for receiving the multicast service.

[0313] In Example 4, the communication parameters corresponding to the feature set index indicate multicast service reception capability, thereby reducing capability report signaling overhead. Furthermore, for the unicast capability part, existing mechanisms can be reused to the maximum extent, and the protocol is slightly modified.

[0314] Furthermore, the communication parameters used to receive multicast services and corresponding to CCs are included in the CC-level communication parameters, which allows for refined capability design at the CC level on the band, improves capability reporting accuracy, and allows the protocol to be slightly modified.

[0315] Four examples of Scheme 1 have been described above. Based on any one of the above examples, in an exemplary description, the downlink feature set indexes may be divided based on the supported communication services. For example, a first index set may be used for a band that supports reception of multicast services, and a second index set may be used for a band that does not support reception of multicast services. In the exemplary description, the first index set may include feature set indexes in a first index range, for example, in the range of 201 to 300. The second index set may include feature set indexes in a second index range, for example, in the range of 101 to 200.

[0316] The index of a communication parameter of any one of the X bands may specifically be a downlink feature set index, and satisfies the following: If a band supports reception of a multicast service, the index of the communication parameter corresponding to the band, i.e., the downlink feature set index, belongs to a first index set. If a band does not support reception of a multicast service, the index of the communication parameter corresponding to the band, i.e., the downlink feature set index, belongs to a second index set. Correspondingly, after receiving the capability information reported by the terminal device, the access network device may determine whether the band supports reception of a multicast service based on the set in which the downlink feature set index of the band is located. Specifically, if the downlink feature set index of the band belongs to the first index set, it may be determined that the band supports reception of a multicast service, or if the downlink feature set index of the band belongs to the second index set, it may be determined that the band does not support reception of a multicast service.

[0317] In a possible implementation, the fact that the communication parameters corresponding to any one of the X bands indicate the communication capability corresponding to the CC on the band can be realized in the following manner: The communication parameters corresponding to any one of the X bands include an index of the communication capability corresponding to the CC on the band.

[0318] In an exemplary embodiment, the communication capability indexes corresponding to CCs may also be divided based on the communication services supported. For example, a third index set may be used for CCs that support reception of multicast services. A fourth index set may be used for CCs that do not support reception of multicast services. In an exemplary embodiment, the third index set may include indexes within a third range. The fourth index set may include indexes within a fourth range.

[0319] The communication capability index corresponding to any CC in any one of the X bands satisfies the following: If the CC supports reception of multicast services, the communication parameter index corresponding to the CC belongs to a third index set; or if the CC does not support reception of multicast services, the communication parameter index corresponding to the CC belongs to a fourth index set. Correspondingly, after receiving the capability information reported by the terminal device, the access network device may determine whether the CC supports reception of multicast services based on the set in which the index corresponding to the CC is located. Specifically, if the index of the CC belongs to the third index set, it may be determined that the CC supports reception of multicast services; or if the index of the CC belongs to the fourth index set, it may be determined that the CC does not support reception of multicast services.

[0320] Method 2: From the above terminology introduction (3), it can be learned that the capability information includes band information, i.e., a band list. In this method, bands that support reception of multicast services may be listed in a band list, and communication parameters corresponding to the bands indicate multicast service reception capabilities on the bands that support reception of multicast services. For example, the communication parameters corresponding to the bands may include a flag indicating that reception of multicast services is supported, a modulation order for receiving multicast services, an SCS for receiving multicast services, and a BW for receiving multicast services. For example, the capability information may be as shown in Table 5. [Table 5]

[0321] Method 2 will be described with reference to Table 5. Table 5 shows band information in the capability information, i.e., a Band List. The Band List may include X bands supported by the terminal device and communication parameters corresponding to each band. If a band supports reception of a multicast service, the communication parameters corresponding to the band include a flag indicating that reception of the multicast service is supported, a modulation order for receiving the multicast service, an SCS for receiving the multicast service, a BW for receiving the multicast service, etc.

[0322] In scheme 2, band-level multicast service reception capability may be indicated, and the protocol is slightly modified.

[0323] It should be noted that the above-described methods 1 and 2 may be implemented separately or may be combined into one solution for implementation. For example, in method 2, a band supporting reception of a multicast service may be indicated, or part of the communication parameters for receiving a multicast service on the band may be indicated. Any example of method 1 indicates other parts of the communication parameters for receiving a multicast service on the band. For example, if band A supports reception of a multicast service, the communication parameters corresponding to band A in the Band List may include a flag indicating that reception of a multicast service is supported and may further include a modulation order for receiving a multicast service on band A. Furthermore, other communication parameters for receiving a multicast service on band A, such as the SCS and BW for receiving a multicast service on band A, or in another example, other CC-level communication parameters for receiving a multicast service on band A, may be indicated by using featureSetCombination.

[0324] For a specific method of indicating other communication parameters for receiving a multicast service on band A by using featureSetCombination, please refer to Examples 1 to 4. The details will not be described again here.

[0325] The above describes a scheme in which the capability information indicates a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a CC.

[0326] Optionally, in addition to the multicast service reception capability corresponding to the band and / or the multicast service reception capability corresponding to the CC, the capability information may further indicate multicast modulation information corresponding to at least one band, where the multicast modulation information is the highest modulation order supported during reception of the multicast service. In an implementation, the multicast modulation information corresponding to the band may be indicated in the communication parameters corresponding to the band in the Band List.

[0327] In an exemplary embodiment, if the highest modulation order supported during reception of a multicast service on the band is a modulation order supported by all terminal devices or a modulation order required for the terminal device, the highest modulation order supported during reception of a multicast service on the band may not be reported in the capability information.

[0328] It can be learned from the above description that the capability information may include band-level multicast modulation information. For example, the communication parameters corresponding to a band in the Band List include the multicast modulation information corresponding to the band. The capability information may further include CC-level multicast modulation information. For example, the CC-level communication parameters indicated by the feature set combination include CC-level multicast modulation information. As shown in Figure 9, the "Multicast Modulation Order" shown in Figure 9 represents the highest modulation order supported during reception of a multicast service.

[0329] In an exemplary embodiment, the CC-level multicast modulation information does not actually limit the maximum order used on the CC, and the access network device may determine the peak rate at which the terminal device receives the multicast service on the CC based on the CC-level multicast modulation information. Under this peak rate constraint, the terminal device may use a modulation order higher than the modulation order, for example, modulation order 1. It should be understood that a prerequisite for using modulation order 1 is that the corresponding band supports modulation order 1. For example, the modulation order supported by the terminal device on CC1 is 64 quadrature amplitude modulation (QAM). The modulation order supported by the band corresponding to CC1 is 256QAM. In this case, the terminal device may use 256QAM on CC1, provided that the peak block length for scheduling 256QAM is equal to or less than the peak block length for scheduling 64QAM.

[0330] Currently, capability information is provided by carrier aggregation ( carrier aggregation , CA) combination structure, and existing CAs have the following requirements:

[0331] When CA is deployed, the frame timing and SFN are aligned between cells that can be aggregated (synchronous CA), or an offset in multiples of slots between the PCell / PSCell and the SCell is configured for the UE (asynchronous CA).

[0332] A terminal device can use CA techniques only when all cells are frame-aligned (in asynchronous CA, the maximum difference between cells is allowed to be no more than half a frame). In a scenario where a terminal device receives unicast and multicast services simultaneously, the unicast and multicast services may be received from different access network devices, and even the two access network devices may not be from one PLMN / operator. Therefore, the access network device cannot determine whether the access network devices are frame-aligned or not. Therefore, scheduling of multicast and / or unicast services by the access network device may exceed the capability range of the terminal device.

[0333] In a possible implementation solution, the capability information sent by the terminal device (which may be the above capability information after multicast extension or unicast capability in the prior art) may further indicate whether the terminal device supports simultaneous reception of unicast and multicast services in synchronous (i.e., frame-aligned) or asynchronous (i.e., frame-unaligned) cases in different capability combinations.

[0334] It should be noted that related solutions indicating whether a terminal device supports simultaneous reception of unicast and multicast services in synchronous (i.e., frame-aligned) or asynchronous (i.e., frame-unaligned) cases in different capability combinations may be implemented independently without relying on the method in FIG. 8.

[0335] In the above scheme, new indication information is introduced to indicate whether simultaneous reception of unicast and multicast services is supported in synchronous (i.e., frame-aligned) or asynchronous (i.e., frame-unaligned) cases in different capability combinations, thereby enabling access network devices to better provide unicast services.

[0336] In another possible implementation solution, the terminal device may be repurposed to indicate whether the capability of asynchronous CA or asynchronous DC is supported. If the terminal device supports asynchronous CA, the terminal device may be considered to support simultaneous reception of unicast and multicast services.

[0337] In yet another possible implementation solution, when reporting unicast capabilities, the terminal device may report a currently available capability combination for multicast services. Optionally, fallback capabilities may also be reported. The fallback capabilities are weakened versions of the existing unicast capabilities. For example, band A supports 100M and band B supports 50M. The fallback capabilities may also be weakened capabilities, such as band A supporting 80M and band B supporting 50M. Specific capability information may be as shown in Table 6 below. [Table 6]

[0338] When the terminal device starts to receive a multicast service based on the reported capability combination, the terminal device may select a usable capability combination and send the capability combination to the network device. For example, the terminal device is currently receiving a unicast service on band A. After the terminal device starts to receive a multicast service (the band for receiving a multicast service is not limited here), the terminal device may further send usable capability combinations, for example, the first row, the second row, and / or the third row, to the network device after the multicast service is received. Specifically, the terminal device may report the usable capability combinations by using an MII procedure or a user assistance information (UAI) procedure.

[0339] The following describes two methods for reporting available capability combinations by a terminal device.

[0340] Method A: The capability information reported by the terminal device carries the identifier (or index) of the capability combination. For example, in Table 3b, the feature set combination corresponding to featureSetCombinationID 1 includes four rows (i.e., four capability combinations), with identifiers 1, 2, 3, and 4, respectively.

[0341] When a terminal device starts receiving a multicast service, the terminal device may select an identifier of a capability combination that supports simultaneous reception of the current unicast service and the multicast service, and report the identifier, specifically, one identifier may be reported, or all identifiers that meet the requirements may be reported.

[0342] Alternatively, when receiving a multicast service, the terminal device reports an identifier of the maximum capability combination of unicast services. Since the capability information reported by the terminal device may not include a capability combination that can simultaneously support unicast and multicast services, in this manner, the maximum capability of the supported unicast services is reported, thereby enabling the access network device to adjust the resources occupied by the unicast services for the terminal device.

[0343] Method B: The terminal device may report the band combination, featureSetCombinationID, and featureSetID of the capability combination. In other words, the terminal device reports the capability information back to the access network device by using an index. Similarly, the capability combination that can be used and reported by the terminal device may be a capability combination that supports simultaneous reception of unicast and multicast services, or may be the maximum capability supported by unicast services when multicast services are satisfied.

[0344] After receiving the indication information reported by the terminal device according to method A or method B, the access network device may provide unicast service in the capability combination indicated by the terminal device.

[0345] In this embodiment of the present application, band-level multicast service reception capability or CC-level multicast service reception capability is reported in the capability information, so that the multicast capability can be reported accurately. Therefore, the access network device can provide multicast service based on the refined capability information, or the terminal device can provide unicast service more accurately.

[0346] Furthermore, by reporting the highest supported modulation order for receiving multicast services and the modulation order for multicast services being received or expected to be received, communication efficiency of multicast and unicast services can be improved.

[0347] Currently, an MII (which may be the above-mentioned extended MII, the existing MII, or an MII that will appear in future communication developments) may be exchanged between access network devices. Access network devices exchange MIIs by using inter-node RRC messages to transmit services that terminal devices are interested in to neighboring access network devices. The MII may include a TMGI that the terminal device is interested in or has received. The TMGI includes PLMN information. The specific format of the TMGI is as follows: [Table 7]

[0348] It may be learned that the PLMN information may be in two forms: one is a PLMN index value (plmn-Index) and the other is a specific PLMN value (explicitValue). For the PLMN index value, the index value reported by the terminal device is the PLMN index value in the PLMN identity list (plmn-IdentityInfoList) or non-public network (NPN) identity list (npn-IdentityInfoList) in SIB1, or a stand-alone non-public network (SNPN) index value.

[0349] The plmn-IdentityInfoList includes a plurality of PLMN-IdentityInfo, each of which includes a plurality of PLMN indices and a cell ID. Specifically, the PLMN index value of PLMNi of cell n may be calculated by using the formula b1+b2+...+b(n-1)+i, where b(n-1) is the number of PLMNs included in cell (n-1). The PLMN index value corresponding to each PLMN may be obtained in this manner.

[0350] The PLMN information in the TMGI received by the terminal device may be a PLMN index value or a PLMN value.

[0351] If the TMGI in the MII reported by the terminal device is reported by using a PLMN index value, when the access network devices exchange MII messages, the terminal device will normally directly forward the MII to other access network devices, and the other access network devices will not be able to determine the PLMN corresponding to the PLMN index value. As a result, the PLMN index value in the TMGI cannot be interpreted, and the other access network devices will not be able to correctly identify the TMGI.

[0352] For the above problem, possible solutions are as follows: The source access network device may send the correspondence to the other access network device. The correspondence is a one-to-one correspondence between one or more PLMN index values ​​and one or more PLMN values. Therefore, after the source access network device receives the indication information from the terminal device, the indication information indicates information (e.g., the above-mentioned MII) about the multicast service that the terminal device is receiving or expects to receive. If the indication information includes at least one PLMN index value, the source access network device may send the indication information to the other access network device. The other access network device may determine the corresponding PLMN based on the correspondence and the PLMN index value included in the indication information.

[0353] It should be noted that this solution may be implemented independently without relying on the method in FIG.

[0354] Below, we will explain four methods for realizing the correspondence relationship.

[0355] Implementation method 1: A source access network device sends PLMN identity information in SIB1 to another access network device, where the PLMN identity information indicates a correspondence relationship. For example, the PLMN identity information may include one or more PLMN values, and the order of the one or more PLMN values ​​indicates a correspondence relationship.

[0356] For example, a source access network device sends PLMN-IdentityInfo to another access network device. Compared with the way in which access network devices exchange SIB1 in LTE, in this way, only necessary information needs to be exchanged, and other unnecessary information in SIB1 is not exchanged much, thereby reducing signaling overhead.

[0357] Implementation Method 2: In the current Xn protocol, cell-related information is transferred in the Xn Setup procedure and the NG-RAN node Configuration Update procedure. The cell-related information includes the PLMN list in the broadcast information of each cell. The PLMN list includes the PLMN list broadcast in the SIB corresponding to each cell (CGI), i.e., plmn-IdentityList in PLMN-IdentityInfo.

[0358] Based on this, the source access network device may indicate the correspondence between the PLMN index value and the specific PLMN value in the cell-related information. For example, the PLMN index value corresponding to the specific PLMN value may be carried in the cell-related information.

[0359] For example, a first access network device sends an Xn interface setup message or an NG-RAN node configuration update message to a second access network device, where the Xn interface setup message or the NG-RAN node configuration update message includes information about at least one cell, and the information about a first cell in the at least one cell indicates at least one PLMN of the first cell and a PLMN index value corresponding to each PLMN.

[0360] Alternatively, the source access network device may match the order of PLMNs in the cell-related information with the order of PLMNs of the cell in SIB1, which may be specifically specified in the protocol or may be realized by the access network device. Furthermore, an offset of the PLMN index value is transferred to other access network devices. Specifically, the offset may be the total number of PLMNs of each cell before the cell. For example, the related information of cell n may include the total number of PLMNs b1 + b2 + ... + b(n-1) of PLMNs of cell 1 to cell (n-1).

[0361] For example, a first access network device sends an Xn interface setup message or an NG-RAN node configuration update message to a second access network device, where the Xn interface setup message or the NG-RAN node configuration update message includes information about at least one cell, and the information about cell n in the at least one cell indicates at least one PLMN and an offset of cell n, where the offset is the total number of PLMNs from cell 1 to cell (n-1) in the at least one cell, and n is an integer greater than 0.

[0362] It should be noted that the order of the correspondence relationship and the indication information is not limited in this application. The correspondence relationship may be transmitted before the indication information, or the indication information may be transmitted before the correspondence relationship, or the correspondence relationship and the indication information may be transmitted simultaneously. For example, the correspondence relationship and the indication information may be transmitted by using a message (or signaling).

[0363] Another possible solution to the above problem is as follows: The terminal device receives service information from the access network device, where the service information includes a first TMGI, and the first TMGI includes a first PLMN index value. After determining the PLMN value corresponding to the first PLMN index value, the terminal device sends an MII to the access network device, where the MII includes a second TMGI, and the second TMGI includes the PLMN value corresponding to the first PLMN index value. The service ID in the first TMGI is the same as the service ID in the second TMGI. The access network device may be an access network device that provides a multicast service to the terminal device.

[0364] In a possible implementation, the second TMGI is a TMGI carried in an application layer message (eg, a service announcement message) received by the terminal device.

[0365] In another possible implementation manner, the second TMG is generated by the terminal device based on the first TMGI and a PLMN value corresponding to the first PLMN index value. For example, the terminal device may replace the first PLMN index value in the first TMGI with the PLMN value corresponding to the first PLMN index value, and then generate the second TMGI.

[0366] Optionally, after receiving the MII reported by the terminal device, the access network device may forward the MII to other access network devices.

[0367] Regarding the above problem, another possible solution is as follows: a source access network device receives first indication information from a terminal device, the first indication information indicating information about a multicast service that the terminal device is receiving or expects to receive, the first indication information including at least one PLMN index value, and the source access network device sends second indication information to other access network devices, the PLMN information in the second indication information being a PLMN value corresponding to the at least one PLMN index value.

[0368] Optionally, the second indication information is obtained by replacing at least one PLMN index value in the first indication information with a PLMN value corresponding to the at least one PLMN index value.

[0369] For example, the first indication information indicates at least one of the following information of the multicast service that the terminal device is receiving or expects to receive: frequency information, TMGI, SCS, or modulation order.

[0370] For example, after receiving the MII reported by the terminal device, if the MII includes a PLMN index value, the source access network device sends a specific PLMN value corresponding to the PLMN index value to other access network devices, for example, the source access network device re-encodes the specific PLMN value and sends the value to other access network devices.

[0371] Currently, when reporting an MII, a terminal device reports a multicast frequency list, multicast service priority, TMGI list, etc. If the terminal device reports the MII before security activation, the transmission of detailed information about the multicast service is insecure, resulting in security risks. However, if the MII is reported after security activation, the access network device allocates unicast service resources, such as an initial BWP, to the terminal device after the terminal device is securely activated. After receiving the MII reported by the terminal device, the access network device reconfigures the initial BWP based on the MII, for example, configuring the bandwidth of the initial BWP as the bandwidth of the CFR. This causes high signaling overhead and long interruption delays for multicast services. Based on this, an embodiment of this application further provides a communication method for reducing signaling overhead and improving multicast service continuity while ensuring communication security. As shown in FIG. 10, the method specifically includes the following steps:

[0372] S1001: A terminal device determines first information and second information.

[0373] The first information indicates that the terminal device is interested in a multicast service, and the second information indicates the multicast service in which the terminal device is interested.

[0374] Optionally, S1001 may be an optional step.

[0375] S1002: The terminal device transmits first information, and the access network device receives the first information in response.

[0376] For example, the first information may include at least one of the following: an interest frequency list, a priority of a multicast service, or a broadcast CFR. Specifically, the terminal device may implicitly indicate that it is interested in a multicast service by using at least one of the interest frequency list, a priority of a multicast service, or a broadcast CFR.

[0377] Alternatively, the terminal device may indicate the first information in other manners, for example, may explicitly indicate the first information by using one bit.

[0378] In the implementation, the interested frequency list, the priority of the multicast service, or the broadcast CFR may alternatively be transmitted after security activation, for example, together with the second information. In this implementation, the terminal device may transmit the first information in another manner, for example, by using one bit to explicitly indicate that the terminal device is interested in the multicast service.

[0379] Specifically, the first information may be transmitted by using an RRCSetupComplete message, an RRCSetupRequest message, or other messages.

[0380] S1003: The access network device configures a frequency domain resource for the terminal device based on the first information, for example, configures an initial BWP for the terminal device, where the bandwidth of the initial BWP is equal to the bandwidth of the CFR.

[0381] S1004: The terminal device transmits the second information, and the access network device receives the second information in response.

[0382] The second information indicates the multicast services in which the terminal device is interested.

[0383] For example, the second information may include a multicast service identifier, a multicast service identifier, or an internet protocol (IP) group address. For example, the multicast service identifier or the multicast service identifier may be a TMGI.

[0384] The second information may be transmitted by using a terminal device assistance information (UEAssistanceInformation), a security mode complete (SecurityModeComplete) message, other messages, etc.

[0385] Optionally, in S1005, the terminal device may receive the multicast service in which it is interested on the configured frequency domain resource, for example, may receive the multicast service in which it is interested in the configured initial BWP.

[0386] The first information is transmitted before the security activation, and the second information is transmitted after the security activation. S1003 may be performed before or after the security activation, which is not particularly limited here.

[0387] In one example, the security activation process may include: the access network device sends a security mode command to the terminal device, where the security mode command carries a key; and the terminal device then sends a security mode complete message to the access network device. Based on this example, in a specific implementation, the first information may be sent before the security mode command is received from the access network device or before the security mode complete message is sent, and the second information may be sent after the security mode complete message is sent.

[0388] In a possible implementation, the terminal device satisfies the following conditions: the cell / access network device accessed by the terminal device provides a multicast service; the cell / access network device accessed by the terminal device is to provide a multicast service; The cell / access network device accessed by the terminal device supports the provision of multicast services; the terminal device is receiving or expects to receive a multicast service in the currently accessed cell / access network device; The multicast service that the terminal device is receiving or expects to receive is / is to be / is supported to be provided by the currently accessed cell / access network device; a cell currently accessed by the terminal device broadcasting an SIB used to provide multicast service information; A cell currently accessed by the terminal device broadcasts a first SIB, the first SIB carrying multicast control configuration information (MCCH); The bandwidth of the CFR of the multicast service provided by the cell currently accessed by the terminal device is different from the bandwidth of the initial BWP configured by using a system message; The bandwidth of the CFR of the multicast service provided by the cell currently accessed by the terminal device is greater than the bandwidth of the initial BWP configured by using a system message, or the terminal device receiving third information from the access network device, the third information indicating that the terminal device transmits the first information before security activation and transmits the second information after security activation; the first information may be transmitted before security activation and the second information may be transmitted after security activation when at least one of the following is satisfied. Optionally, the third information is carried in a broadcast message.

[0389] In this embodiment of the present application, before security activation, the access network device is informed that the terminal device is interested in a multicast service, thereby enabling the access network device to configure resources, such as CFR, to be used for the multicast service for the terminal device. Therefore, after the resources to be used for the unicast service are configured, the resources do not need to be reconfigured based on the multicast service. For example, after the initial bandwidth portion (initial BWP) is configured, the bandwidth of the initial BWP does not need to be configured as the bandwidth of the CFR based on the multicast service. This method can help reduce signaling overhead and ensure the continuity of the multicast service. Furthermore, information related to the multicast service in which the terminal device is interested is transmitted after security activation, thereby preventing specific information of the MBS from being transmitted in an insecure environment and improving communication security.

[0390] It should be noted that the method in Fig. 7 and the method in Fig. 10 may be realized separately as independent solutions, or may be combined into one solution for realization. For example, in the method in Fig. 7, the terminal device may send an MII to the access network device by using the method in Fig. 10, specifically, send the first information before security activation. Specifically, the first information may be implicitly indicated by using information such as an interest frequency list, a priority of a multicast service, or a broadcast CFR, or may be explicitly indicated by using one bit, and the second information is sent after security activation.

[0391] In a specific implementation, in an implementation where the first information is explicitly indicated by using one bit, information such as a frequency of interest list for a multicast service being received or expected to be received, a priority of the multicast service, a broadcast CFR, or a modulation order may be transmitted before security activation, e.g., transmitted together with the first information, or may be transmitted after security activation, e.g., transmitted together with the second information. Alternatively, part of the information such as a frequency of interest list for a multicast service being received or expected to be received, a priority of the multicast service, a broadcast CFR, or a modulation order may be transmitted before security activation, and another part of the information is transmitted after security activation.

[0392] Based on the same concept as the method embodiment, an embodiment of this application provides a communication device. The structure of the communication device may be as shown in Figure 11. The communication device includes: a communication module 1101 and a processing module 1102.

[0393] In an implementation manner, a communication apparatus may be specifically configured to implement the method performed by the terminal device in the embodiment in Fig. 7. The apparatus may be a terminal device, or may be a chip, chipset, or part of a chip located in the terminal device and configured to perform the functions of the associated method. The processing module 1102 is configured to determine capability information, where the capability information indicates a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC. The communication module 1101 is configured to send the capability information to the access network device.

[0394] Optionally, the communication module 1101 is further configured to send indication information to the access network device, the indication information indicating a modulation order for a multicast service that the terminal device is receiving or expects to receive.

[0395] Optionally, the communication module 1101 is further configured to receive capability reporting instruction information from the access network device before the processing module 1102 determines the capability information, and the capability reporting instruction information instructs the terminal device to report its multicast service reception capability.

[0396] For example, the capability information includes identifiers of a first band combination list and a first feature set combination, the first band combination list includes first band information, the first band information includes identifiers of N bands that support reception of a multicast service, N is an integer greater than 0, the first feature set combination includes at least one first parameter set corresponding to the first band combination list, and any one of the first parameter sets indicates a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands.

[0397] Optionally, the first band combination list further includes second band information, wherein the second band information includes identifiers of M bands supporting unicast services, where M is an integer greater than 0, and wherein any of the first parameter sets further indicates unicast service reception capabilities corresponding to each of the M bands, or any of the first parameter sets further indicates communication service reception capabilities corresponding to each of the M bands, where the communication services include unicast services and multicast services.

[0398] For example, the capability information includes identifiers of a second band combination list and a second feature set combination, where the second band combination list includes identifiers of N bands that support reception of multicast services, where N is an integer greater than 0, the second feature set combination includes Q1 groups of parameters corresponding to the second band combination list, where each group of parameters includes Q2 second parameter sets, where any of the second parameter sets indicates a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, where Q1 is an integer greater than 0 and Q2 is an integer greater than 0.

[0399] Optionally, the capability information further includes a third band combination list, the third band combination list including identifiers of M bands that support reception of unicast services, where M is an integer greater than 0; the second feature set combination further includes Q2 third parameter sets corresponding to the third band combination list, where any third parameter set indicates a unicast service reception capability corresponding to each of the M bands; and a second parameter set i among the Q2 second parameter sets corresponds to a first parameter set i among parameters of any of the Q1 groups, where i is an integer greater than 0 and not greater than Q2.

[0400] For example, the capability information includes identifiers of a second band combination list and Q1 third feature set combinations, where the second band combination list includes identifiers of N bands that support reception of multicast services, where N is an integer greater than 0, and any of the third feature set combinations includes Q2 fourth parameter sets, where any of the fourth parameter sets indicates a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, where Q1 is an integer greater than 0 and Q2 is an integer greater than 0.

[0401] Optionally, the capability information further includes identifiers of a third band combination list and a fourth feature set combination, where the third band combination includes identifiers of M bands supporting reception of unicast services, where M is an integer greater than 0, and the fourth feature set combination includes Q2 fifth parameter sets, where any one of the fifth parameter sets indicates a unicast service reception capability corresponding to each of the M bands.

[0402] For example, the capability information includes identifiers of a fourth band combination list and a fifth feature set combination, the fourth band combination list including identifiers of X bands supported by the terminal device, where X is an integer greater than 0, the fifth feature set combination including at least one sixth parameter set, where any sixth parameter set indicates communication parameters corresponding to each of the X bands, where the X bands include N bands that support reception of multicast services, the communication parameters corresponding to any one of the N bands indicate a multicast service reception capability corresponding to the band and / or a communication capability corresponding to a CC on the band, where if the CC supports reception of multicast services, the communication capability corresponding to the CC is the multicast service reception capability corresponding to the CC, and N is an integer greater than 0 but not greater than X.

[0403] Optionally, any sixth parameter set indicating communication parameters corresponding to each of the X bands includes: Any sixth parameter set includes an index of communication parameters corresponding to each of the X bands, and the index of the communication parameters for any one of the X bands satisfies: if a band supports reception of a multicast service, the index of the communication parameters corresponding to the band belongs to a first index set, and if the band does not support reception of a multicast service, the index of the communication parameters corresponding to the band belongs to a second index set.

[0404] Optionally, the communication parameters corresponding to any one of the N bands indicating a communication capability corresponding to a CC on the band includes: the communication parameters corresponding to any one of the N bands include an index of a communication capability corresponding to a CC on the band, and the index of the communication capability corresponding to any CC on the band satisfies the following: if the CC supports reception of a multicast service, the index of the communication capability corresponding to the CC belongs to a third index set, and if the CC does not support reception of a multicast service, the index of the communication capability corresponding to the CC belongs to a fourth index set.

[0405] In an exemplary illustration, the multicast service reception capability corresponding to a band includes at least one of the following: that the band supports reception of multicast services, or communication parameters for receiving multicast services on the band.

[0406] In an exemplary description, the multicast service reception capability corresponding to a CC includes information that the CC supports reception of a multicast service and / or communication information for receiving a multicast service on the CC, where the communication information is communication parameters for receiving a multicast service on the CC, or the communication information is a capability value of the CC, where the capability value is determined based on communication parameters for receiving a multicast service on the CC.

[0407] Additionally, the communication parameters for receiving the multicast service include a maximum modulation order supported during reception of the multicast service.

[0408] In an implementation manner, a communication apparatus may be specifically configured to implement the method performed by the access network device in the embodiment in Fig. 7. The apparatus may be the access network device, or may be a chip, chipset, or part of a chip located in the access network device and configured to perform the functions of the associated method. The communication module 1101 is configured to receive capability information from a terminal device, where the capability information indicates a multicast service reception capability corresponding to a band and / or a multicast service reception capability corresponding to a component carrier CC. The processing module 1102 is configured to determine the capability of the terminal device based on the capability information.

[0409] Optionally, the communication module 1101 is further configured to receive indication information from the terminal device, the indication information including a modulation order for a multicast service that the terminal device is receiving or expects to receive.

[0410] Optionally, the communication module 1101 is further configured to send capability report indication information to the terminal device before the capability information from the terminal device is received, where the capability report indication information instructs the terminal device to report its multicast service reception capability.

[0411] For example, the capability information includes identifiers of a first band combination list and a first feature set combination, the first band combination list includes first band information, the first band information includes identifiers of N bands that support reception of a multicast service, N is an integer greater than 0, the first feature set combination includes at least one first parameter set corresponding to the first band combination list, and any one of the first parameter sets indicates a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands.

[0412] Optionally, the first band combination list further includes second band information, wherein the second band information includes identifiers of M bands supporting unicast services, where M is an integer greater than 0, and wherein any of the first parameter sets further indicates unicast service reception capabilities corresponding to each of the M bands, or any of the first parameter sets further indicates communication service reception capabilities corresponding to each of the M bands, where the communication services include unicast services and multicast services.

[0413] For example, the capability information includes identifiers of a second band combination list and a second feature set combination, where the second band combination list includes identifiers of N bands that support reception of multicast services, where N is an integer greater than 0, the second feature set combination includes Q1 groups of parameters corresponding to the second band combination list, where each group of parameters includes Q2 second parameter sets, where any of the second parameter sets indicates a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, where Q1 is an integer greater than 0 and Q2 is an integer greater than 0.

[0414] Optionally, the capability information further includes a third band combination list, the third band combination list including identifiers of M bands that support reception of unicast services, where M is an integer greater than 0; the second feature set combination further includes Q2 third parameter sets corresponding to the third band combination list, where any third parameter set indicates a unicast service reception capability corresponding to each of the M bands; and a second parameter set i among the Q2 second parameter sets corresponds to a first parameter set i among parameters of any of the Q1 groups, where i is an integer greater than 0 and not greater than Q2.

[0415] For example, the capability information includes identifiers of a second band combination list and Q1 third feature set combinations, where the second band combination list includes identifiers of N bands that support reception of multicast services, where N is an integer greater than 0, and any of the third feature set combinations includes Q2 fourth parameter sets, where any of the fourth parameter sets indicates a multicast service reception capability corresponding to each of the N bands and / or a multicast service reception capability corresponding to a CC in each of the N bands, where Q1 is an integer greater than 0 and Q2 is an integer greater than 0.

[0416] Optionally, the capability information further includes identifiers of a third band combination list and a fourth feature set combination, where the third band combination includes identifiers of M bands supporting reception of unicast services, where M is an integer greater than 0, and the fourth feature set combination includes Q2 fifth parameter sets, where any one of the fifth parameter sets indicates a unicast service reception capability corresponding to each of the M bands.

[0417] For example, the capability information includes identifiers of a fourth band combination list and a fifth feature set combination, the fourth band combination list including identifiers of X bands supported by the terminal device, where X is an integer greater than 0, the fifth feature set combination including at least one sixth parameter set, where any sixth parameter set indicates communication parameters corresponding to each of the X bands, where the X bands include N bands that support reception of multicast services, the communication parameters corresponding to any one of the N bands indicate a multicast service reception capability corresponding to the band and / or a communication capability corresponding to a CC on the band, where if the CC supports reception of multicast services, the communication capability corresponding to the CC is the multicast service reception capability corresponding to the CC, and N is an integer greater than 0 but not greater than X.

[0418] Optionally, any sixth parameter set indicating communication parameters corresponding to each of the X bands includes: Any sixth parameter set includes an index of communication parameters corresponding to each of the X bands, and the index of the communication parameters for any one of the X bands satisfies: if a band supports reception of a multicast service, the index of the communication parameters corresponding to the band belongs to a first index set, and if the band does not support reception of a multicast service, the index of the communication parameters corresponding to the band belongs to a second index set.

[0419] Optionally, the communication parameters corresponding to any one of the N bands indicating a communication capability corresponding to a CC on the band includes: the communication parameters corresponding to any one of the N bands include an index of a communication capability corresponding to a CC on the band, and the index of the communication capability corresponding to any CC on the band satisfies the following: if the CC supports reception of a multicast service, the index of the communication capability corresponding to the CC belongs to a third index set, and if the CC does not support reception of a multicast service, the index of the communication capability corresponding to the CC belongs to a fourth index set.

[0420] In an exemplary illustration, the multicast service reception capability corresponding to a band includes at least one of the following: that the band supports reception of multicast services, or communication parameters for receiving multicast services on the band.

[0421] In an exemplary description, the multicast service reception capability corresponding to a CC includes information that the CC supports reception of a multicast service and / or communication information for receiving a multicast service on the CC, where the communication information is communication parameters for receiving a multicast service on the CC, or the communication information is a capability value of the CC, where the capability value is determined based on communication parameters for receiving a multicast service on the CC.

[0422] Additionally, the communication parameters for receiving the multicast service include a maximum modulation order supported during reception of the multicast service.

[0423] The module division in the embodiments of this application is an example and is merely a logical functional division, and other divisions may be used in actual implementation. Furthermore, the functional modules in the embodiments of this application may be integrated into one processor, or may exist physically alone, or two or more modules may be integrated into one module. The integrated module may be implemented in the form of hardware, or may be implemented in the form of a software functional module. It may be understood that for the functions or implementation methods of the modules in the embodiments of this application, further reference may be made to the relevant descriptions in the method embodiments.

[0424] In a possible implementation, the communication device may be as shown in FIG. 12. The device may be a communication device or a chip within a communication device. The communication device may be the terminal device in the above embodiments or the network device in the above embodiments. The device includes a processor 1201 and a communication interface 1202, and may further include a memory 1203. The processing module 1102 may be the processor 1201. The communication module 1101 may be the communication interface 1202.

[0425] The processor 1201 may be a CPU, a digital processing unit, etc. The communication interface 1202 may be a transceiver, an interface circuit such as a transceiver circuit, a transceiver chip, etc. The device further includes a memory 1203 configured to store programs executed by the processor 1201. The memory 1203 may be a non-volatile memory, such as a hard disk drive (HDD) or a solid state drive (SSD), or a volatile memory, such as a random access memory (RAM). The memory 1203 may be any other medium usable for carrying or storing expected program code in the form of instructions or data structures and accessible by a computer, without being limited thereto.

[0426] The processor 1201 is configured to execute program codes stored in the memory 1203, and is specifically configured to perform the operations of the processing module 1102. Details will not be described again in this application. The communication interface 1202 is specifically configured to perform the operations of the communication module 1101. Details will not be described again in this application.

[0427] In this embodiment of the application, the specific connection medium between the communication interface 1202, the processor 1201, and the memory 1203 is not limited. According to this embodiment of the application, in FIG. 12, the memory 1203, the processor 1201, and the communication interface 1202 are connected to each other through a bus 1204. In FIG. 12, the bus is represented by using a thick line. The manner of connection between other components is merely an example for explanation and is not used as a limitation. The bus may be classified into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is shown in FIG. 12, but this does not mean that there is only one bus or only one type of bus.

[0428] An embodiment of the present invention further provides a computer-readable storage medium configured to store computer software instructions that need to be executed for execution of the above-mentioned processor, the computer-readable storage medium including a program that needs to be executed for execution of the above-mentioned processor.

[0429] An embodiment of the present application further provides a communication system including a communication device configured to implement the functions of a terminal device in the embodiment of FIG. 7 and a communication device configured to implement the functions of a network device in the embodiment of FIG. 7.

[0430] An embodiment of the present application further provides a communication system including a communication device configured to implement the functions of a terminal device in the embodiment of FIG. 10 and a communication device configured to implement the functions of a network device in the embodiment of FIG. 10.

[0431] Those skilled in the art should understand that the embodiments of this application may be provided as a method, a system, or a computer program product. Therefore, this application may take the form of a hardware-only embodiment, a software-only embodiment, or an embodiment having a combination of software and hardware. Furthermore, this application may take the form of a computer program product embodied in one or more computer-usable storage media (including, but not limited to, disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0432] This application is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to this application. It should be understood that computer program instructions may be used to implement each procedure and / or each block in the flowcharts and / or block diagrams, and combinations of procedures and / or blocks in the flowcharts and / or block diagrams. These computer program instructions may be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or any other programmable data processing device to produce a machine, whereby the instructions, executed by the processor of the computer or any other programmable data processing device, produce an apparatus for implementing the particular functionality of one or more processes in the flowcharts and / or one or more blocks in the block diagrams.

[0433] These computer program instructions may be stored in a computer-readable memory that can instruct a computer or any other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable memory generate an artifact that includes an instruction apparatus that implements a particular function in one or more processes in the flowcharts and / or one or more blocks in the block diagrams.

[0434] The computer program instructions may alternatively be loaded into a computer or other programmable data processing device such that a sequence of operations and steps are executed on the computer or other programmable device, thereby creating a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing a particular function in one or more procedures in the flowcharts and / or one or more blocks in the block diagrams.

[0435] It is apparent that those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. This application intends to cover these modifications and variations of this application, provided that they fall within the scope of protection defined by the following claims and their equivalent technologies.

Claims

1. 1. A method of communication, the method comprising: receiving, by a source access network device, first indication information from a terminal device, the first indication information indicating that the terminal device is receiving or is interested in receiving a multicast service, the first indication information including a public land mobile network (PLMN) index value; sending, by the source access network device, second indication information to the target access network device, wherein the second indication information includes PLMN values, the PLMN index values ​​are replaced with the PLMN values, and a one-to-one correspondence exists between one or more PLMN index values ​​and one or more PLMN values; A method comprising:

2. The method of claim 1 , wherein the PLMN value in the second indication corresponds to the PLMN index value in the first indication.

3. The method of claim 1 , wherein the second indication information is obtained by replacing the PLMN index value in the first indication information with the PLMN value.

4. The method of claim 1 , wherein the second indication information is forwarded from the source access network device to the target access network device.

5. 2. The method of claim 1, wherein the PLMN index value in the first indication information is included in a Temporary Mobile Group Identity (TMGI) that a terminal device is interested in receiving or has received, and the PLMN value in the second indication information is included in a TMGI that a terminal device is interested in receiving or has received.

6. The method of claim 1 , wherein the first indication information or the second indication information is an MBS interest indication (MII).

7. 2. The method of claim 1, wherein the first indication information indicates at least one of the following information of the multicast service that the terminal device is receiving or is interested in receiving: frequency information, TMGI, SCS, or modulation order.

8. 1. A method of communication, the method comprising: sending, by the terminal device, first indication information to the source access network device, the first indication information indicating that the terminal device is receiving or expects to receive a multicast service, the first indication information including a public land mobile network (PLMN) index value; Including, the PLMN index value is used to obtain a PLMN value of second indication information, the second indication information is sent from the source access network device to a target access network device, the PLMN index value is replaced with the PLMN value, and a correspondence between the one or more PLMN index values ​​and the one or more PLMN values ​​is a one-to-one correspondence.

9. The method of claim 8 , wherein the PLMN value in the second indication corresponds to the PLMN index value in the first indication.

10. The method of claim 8 , wherein the second indication information is obtained by replacing the PLMN index value in the first indication information with the PLMN value.

11. The method of claim 8 , wherein the second indication information is forwarded from the source access network device to the target access network device.

12. 9. The method of claim 8, wherein the PLMN index value in the first indication information is included in a Temporary Mobile Group Identity (TMGI) that a terminal device is interested in receiving or has received, and the PLMN value in the second indication information is included in a TMGI that a terminal device is interested in receiving or has received.

13. The method of claim 8 , wherein the first indication information or the second indication information is an MBS interest indication (MII).

14. 9. The method of claim 8, wherein the first indication information indicates at least one of the following information of the multicast service that the terminal device is receiving or is interested in receiving: frequency information, TMGI, SCS, or modulation order.

15. 1. A communications device, the device including a processor, the processor comprising: receiving first indication information from a terminal device, the first indication information indicating that the terminal device is receiving or is interested in receiving a multicast service, the first indication information including a public land mobile network (PLMN) index value; sending second indication information to the target access network device, wherein the second indication information includes a PLMN value, the PLMN index value is replaced with the PLMN value, and a correspondence relationship between the one or more PLMN index values ​​and the one or more PLMN values ​​is a one-to-one correspondence relationship; 20. An apparatus configured to:

16. The apparatus of claim 15 , wherein the PLMN value in the second indication corresponds to the PLMN index value in the first indication.

17. The apparatus of claim 15 , wherein the second indication information is obtained by replacing the PLMN index value in the first indication information with the PLMN value.

18. The apparatus of claim 15 , wherein the second indication information is forwarded from a source access network device to the target access network device.

19. 16. The apparatus of claim 15, wherein the PLMN index value in the first indication information is included in a Temporary Mobile Group Identity (TMGI) that a terminal device is interested in receiving or has received, and the PLMN value in the second indication information is included in a TMGI that a terminal device is interested in receiving or has received.

20. The device of claim 15 , wherein the first indication information or the second indication information is an MBS interest indication (MII).

21. 16. The apparatus of claim 15, wherein the first indication information indicates at least one of the following information of the multicast service that the terminal device is receiving or is interested in receiving: frequency information, TMGI, SCS, or modulation order.

22. 1. A communications device, the device including a processor, the processor comprising: sending first indication information to a source access network device, the first indication information indicating that a terminal device is receiving or expects to receive a multicast service, the first indication information including a public land mobile network (PLMN) index value; configured to run the PLMN index value is used to obtain a PLMN value of second indication information, the second indication information is sent from the source access network device to a target access network device, the PLMN index value is replaced with the PLMN value, and a correspondence between the one or more PLMN index values ​​and the one or more PLMN values ​​is a one-to-one correspondence, the device.

23. 23. The apparatus of claim 22, wherein the PLMN value in the second indication corresponds to the PLMN index value in the first indication.

24. The apparatus of claim 22 , wherein the second indication information is obtained by replacing the PLMN index value in the first indication information with the PLMN value.

25. The apparatus of claim 22 , wherein the second indication information is forwarded from the source access network device to the target access network device.

26. 23. The apparatus of claim 22, wherein the PLMN index value in the first indication information is included in a Temporary Mobile Group Identity (TMGI) that a terminal device is interested in receiving or has received, and the PLMN value in the second indication information is included in a TMGI that a terminal device is interested in receiving or has received.

27. The apparatus of claim 22 , wherein the first indication information or the second indication information is an MBS interest indication (MII).

28. 23. The apparatus of claim 22, wherein the first indication information indicates at least one of the following information of the multicast service that the terminal device is receiving or is interested in receiving: frequency information, TMGI, SCS, or modulation order.

29. 1. A computer-readable storage medium, comprising:

15. The computer readable storage medium is configured to store computer instructions that, when executed on a computer, enable the computer to perform the method of any one of claims 1 to 14.

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