Communication method and device

Abstract

The invention discloses a communication method and device, and relates to the field of communication. The method comprises the following steps: a first network device sends an RRC release message to a terminal device joining a multicast session, wherein the RRC release message is used for indicating that the terminal device is released to a non-connection state; and the first network equipment sends indication information to the second network equipment, wherein the indication information is used for indicating whether the multicast broadcast radio bearer needs to be reconfigured for the terminal equipment. And the second network device reconfigures the multicast broadcast radio bearer for the terminal device according to the indication information, or does not reconfigure the multicast broadcast radio bearer for the terminal device. According to the invention, the indication information is sent to the second network equipment, so that a decision basis for whether to reconfigure the multicast broadcast wireless bearer for the terminal equipment is provided for the second network equipment.

Description

Technical Field

[0001] The present application relates to the field of communications, and in particular to a communication method and device. Background Art

[0002] Multicast service is a method of transmitting service data to multiple terminal devices in a group through multicast. Terminal devices can receive multicast service data in a connected state. For some user-intensive scenarios, such as concerts, stadiums, and other public safety scenarios, when the number of multicast users (i.e., the number of UEs) in a cell is too large, it may exceed the number of connected users that the cell can accommodate, resulting in network congestion and affecting the user service experience. In order to alleviate network congestion, the base station can support terminal devices that join the multicast session to receive multicast services in a non-connected state.

[0003] Generally speaking, the reasons why a terminal device is released to a non-connected state include: service deactivation or the network congestion mentioned above. When a terminal device accesses a new cell from an old cell, and the base station corresponding to the new cell (which may be referred to as a new base station) is different from the base station corresponding to the old cell (which may be referred to as an old base station), if the terminal device is released to a non-connected state due to service deactivation, the new base station may not reconfigure the multicast broadcast radio bearer; if the terminal device is released to a non-connected state to receive multicast services due to network congestion, the multicast broadcast radio bearers of the new and old cells may be different, or the terminal device continues to use the multicast broadcast radio bearer to receive data in a non-connected state, resulting in a possible change in the radio bearer configuration in the terminal device. The new cell is not sure whether the multicast broadcast radio bearer configuration on the terminal device side has changed, and cannot determine whether the terminal device can continue to use the multicast broadcast radio bearer used in the old cell in the new cell, or cannot determine the multicast broadcast radio bearer configuration stored on the terminal device side, and the new base station needs to reconfigure the multicast broadcast radio bearer.

[0004] At present, the new base station cannot distinguish whether the reason why the connected terminal device is released to the non-connected state is due to service deactivation or being released to the non-connected state to receive multicast services. This may cause the new base station to be unable to determine how to configure the multicast broadcast radio bearer. There is no feasible solution to the problem of reconfiguration of the multicast broadcast radio bearer. Summary of the invention

[0005] The present application provides a communication method and apparatus, which can provide a second network device with a decision basis for whether to reconfigure a multicast broadcast wireless bearer for a terminal device by sending indication information to the second network device.

[0006] In a first aspect, the present application provides a communication method that can be applied to a first network device. The method includes: sending a radio resource control release message to a terminal device that joins a multicast session, the radio resource control release message is used to instruct the terminal device to release to a non-connected state; sending indication information to a second network device, the indication information is used to indicate whether it is necessary to reconfigure a multicast broadcast radio bearer for the terminal device.

[0007] The method sends indication information to the second network device through the first network device, indicating whether the second network device needs to reconfigure the multicast broadcast radio bearer for the terminal device joining the multicast session. This allows the second network device to clearly know whether the multicast broadcast radio bearer needs to be reconfigured for the terminal device when the terminal device accesses, and provides the second network device with a decision-making basis for reconfiguring the multicast broadcast radio bearer.

[0008] In one possible design, when the terminal device is released to a non-connected state to receive multicast services, the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device; or, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device.

[0009] In this design, for the scenario where the terminal device is released to a non-connected state to receive multicast services and access the second network device, the second network device can reconfigure the multicast broadcast radio bearer for the terminal device. For the scenario where the terminal device accesses the second network device after the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated and the terminal device is released to a non-connected state, the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device, thereby reducing part of the signaling overhead.

[0010] In one possible design, the indication information is specifically used to indicate whether the terminal device is released to a non-connected state to receive multicast services; or, the indication information is specifically used to indicate that the terminal device is released to a non-connected state to receive multicast service information; or, the indication information includes: suspension configuration information, and the suspension configuration information is used to indicate that the terminal device is released to a non-connected state to receive multicast service information.

[0011] This design indicates whether the terminal device is released to a non-connected state to receive multicast services through indication information, and can indicate to the second network device whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device with a small signaling overhead. When the second network device reconfigures the multicast broadcast radio bearer for the terminal device, it can perform MRB reconfiguration for all multicast services received by the terminal device. By indicating the multicast service information that the terminal device is released to a non-connected state to receive, the second network device can be instructed to accurately reconfigure the multicast broadcast radio bearer for the multicast service that the terminal device is released to a connected state to receive. By suspending the configuration information to indicate the multicast service information that the terminal device is released to a non-connected state to receive, the second network device can be instructed to accurately reconfigure the multicast broadcast radio bearer for the multicast service that the terminal device is released to a connected state to receive.

[0012] In one possible design, the indication information includes a wireless resource control connection release message, and the wireless resource control connection release message includes suspension configuration information.

[0013] In this design, the first network device can also use the RRC release message as indication information, and indicate to the second network device through the suspension configuration information in the RRC release message that the terminal device is released to the non-connected state to receive the multicast service information. By using the RRC release message as indication information, it is also possible to instruct the second network device to accurately reconfigure the multicast broadcast radio bearer for the multicast service that the terminal device is released to receive in the connected state.

[0014] In one possible design, the method further includes: determining capability information of the second network device, the capability information including whether to support sending multicast services to non-connected terminal devices.

[0015] The sending of indication information to the second network device includes: when the second network device supports a terminal device in a non-connected state to send a multicast service, sending indication information to the second network device.

[0016] In this design, the first network device can send indication information only to the second network device that supports sending multicast services to the terminal device in a non-connected state, indicating whether the second network device needs to reconfigure the multicast broadcast radio bearer for the terminal device. For the second network device that does not support sending multicast services to the terminal device in a non-connected state, it is not necessary to send indication information, which can reduce signaling waste.

[0017] In one possible design, determining the capability information of the second network device includes: determining the capability information of the second network device when the Xn interface between the second network device is established or modified; or, determining the capability information of the second network device based on a terminal device context migration request message from the second network device; or, determining the capability information of the second network device based on operation, maintenance and management configuration information.

[0018] In this design, when the Xn interface between the first network device and the second network device is established or modified, the capability information of the second network device is determined, and the capability information of the second network device can be obtained by using the control plane message or user plane message of the Xn interface, thereby reducing signaling overhead. The first network device determines the capability information of the second network device based on the terminal device context migration request message from the second network device, and the capability information of the second network device can be obtained by using the terminal device context migration request message, thereby reducing signaling overhead. The capability information of the second network device is synchronized to the first network device by using OAM configuration information, without using other messages, thereby reducing signaling overhead.

[0019] In one possible design, the sending of indication information to the second network device includes: sending a terminal device context migration response message corresponding to the terminal device to the second network device, the terminal device context migration response message including the indication information; or, sending indication information to at least one network device within the wireless coverage range of the first network device, the at least one network device including the second network device; or, sending indication information to the second network device via a paging message.

[0020] In this design, the first network device sends indication information to the second network device through the terminal device context migration response message to indicate whether the terminal device needs to be MRB reconfigured. The indication information can be sent using existing messages, which can save signaling overhead and reduce implementation costs.

[0021] In a second aspect, the present application provides a communication device having the function of implementing the method described in the first aspect. The function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the function of the method described in the first aspect, for example, a sending unit.

[0022] Among them, the sending unit is used to send a wireless resource control release message to the terminal device joining the multicast session, and the wireless resource control release message is used to instruct the terminal device to release to a non-connected state; the sending unit is also used to send indication information to the second network device, and the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast wireless bearer for the terminal device.

[0023] In one possible design, when the terminal device is released to a non-connected state to receive multicast services, the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device; or, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device.

[0024] In one possible design, the indication information is specifically used to indicate whether the terminal device is released to a non-connected state to receive multicast services; or, the indication information is specifically used to indicate that the terminal device is released to a non-connected state to receive multicast service information; or, the indication information includes: suspension configuration information, and the suspension configuration information is used to indicate that the terminal device is released to a non-connected state to receive multicast service information.

[0025] In one possible design, the indication information includes a wireless resource control connection release message, and the wireless resource control connection release message includes suspension configuration information.

[0026] In one possible design, the apparatus further includes: a processing unit, configured to determine capability information of the second network device, wherein the capability information includes whether to support sending multicast services to a terminal device in a non-connected state.

[0027] The sending unit is specifically used to send indication information to the second network device when the second network device supports the terminal device in the non-connected state to send multicast services.

[0028] In one possible design, the processing unit is specifically used to determine the capability information of the second network device when the Xn interface between the second network device is established or modified; or, to determine the capability information of the second network device based on a terminal device context migration request message from the second network device; or, to determine the capability information of the second network device based on operation, maintenance and management configuration information.

[0029] In one possible design, the sending unit is specifically used to send a terminal device context migration response message corresponding to the terminal device to the second network device, and the terminal device context migration response message includes indication information; or, send indication information to at least one network device within the wireless coverage range of the first network device, and the at least one network device includes the second network device; or, send indication information to the second network device through a paging message.

[0030] In a third aspect, the present application also provides a communication device, comprising: a processor, configured to execute computer instructions stored in a memory, wherein when the computer instructions are executed, the device executes the method described in the first aspect or any possible design of the first aspect.

[0031] In a fourth aspect, the present application also provides a communication device, comprising: a processor and an interface circuit, the processor being used to communicate with other devices through the interface circuit and execute the method described in the first aspect or any possible design of the first aspect.

[0032] The communication devices described in the second to fourth aspects above can be applied to network equipment, such as the first network equipment.

[0033] In a fifth aspect, the present application also provides a computer-readable storage medium, comprising: computer software instructions; when the computer software instructions are executed in a network device or in a chip built into the network device, the network device executes the method described in the first aspect or any possible design of the first aspect.

[0034] It can be understood that the beneficial effects that can be achieved by the second to fifth aspects provided above can refer to the beneficial effects in the first aspect and any possible design thereof, and will not be repeated here.

[0035] In a sixth aspect, the present application provides a communication method that can be applied to a second network device. The method includes: receiving indication information from a first network device, the indication information is used to indicate whether a multicast broadcast radio bearer needs to be reconfigured for a terminal device, and the terminal device is a terminal device that joins a multicast session; when the indication information indicates that a multicast broadcast radio bearer needs to be reconfigured for the terminal device, sending a reconfigured multicast broadcast radio bearer to the terminal device.

[0036] In the method, the second network device can decide whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device joining the multicast session according to the indication information.

[0037] In one possible design, when the terminal device is released to a non-connected state to receive multicast services, the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device; or, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device.

[0038] In this design, for the scenario where the terminal device is released to a non-connected state to receive multicast services and access the second network device, the second network device can reconfigure the multicast broadcast radio bearer for the terminal device. For the scenario where the terminal device accesses the second network device after the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated and the terminal device is released to a non-connected state, the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device, thereby reducing part of the signaling overhead.

[0039] In one possible design, the indication information is specifically used to indicate whether the terminal device is released to a non-connected state to receive multicast services; or, the indication information is specifically used to indicate that the terminal device is released to a non-connected state to receive multicast service information; or, the indication information includes: suspension configuration information, and the suspension configuration information is used to indicate that the terminal device is released to a non-connected state to receive multicast service information.

[0040] When the indication information indicates that the terminal device is released to a non-connected state to receive multicast services, sending a reconfigured multicast broadcast radio bearer to the terminal device includes: sending a reconfigured multicast broadcast radio bearer for all multicast services of the terminal device to the terminal device.

[0041] Alternatively, when the indication information indicates that the terminal device is released to a non-connected state to receive multicast service information, or the indication information includes suspension configuration information, the sending of a reconfigured multicast broadcast radio bearer to the terminal device includes: sending to the terminal device a multicast broadcast radio bearer that is reconfigured for the multicast service that the terminal device is released to a connected state to receive.

[0042] This design indicates whether the terminal device is released to a non-connected state to receive multicast services through indication information, and can indicate to the second network device whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device with a small signaling overhead. When the second network device reconfigures the multicast broadcast radio bearer for the terminal device, it can perform MRB reconfiguration for all multicast services received by the terminal device. By indicating the multicast service information that the terminal device is released to a non-connected state to receive, the second network device can be instructed to accurately reconfigure the multicast broadcast radio bearer for the multicast service that the terminal device is released to a connected state to receive. By suspending the configuration information to indicate the multicast service information that the terminal device is released to a non-connected state to receive, the second network device can be instructed to accurately reconfigure the multicast broadcast radio bearer for the multicast service that the terminal device is released to a connected state to receive.

[0043] In one possible design, the indication information includes a wireless resource control connection release message, and the wireless resource control connection release message includes suspension configuration information.

[0044] In this design, the first network device can also use the RRC release message as indication information, and indicate to the second network device through the suspension configuration information in the RRC release message that the terminal device is released to the non-connected state to receive the multicast service information. By using the RRC release message as indication information, it is also possible to instruct the second network device to accurately reconfigure the multicast broadcast radio bearer for the multicast service that the terminal device is released to receive in the connected state.

[0045] In one possible design, the second network device supports sending multicast services to non-connected terminal devices.

[0046] In this design, the first network device can send indication information only to the second network device that supports sending multicast services to the terminal device in a non-connected state, indicating whether the second network device needs to reconfigure the multicast broadcast radio bearer for the terminal device. For the second network device that does not support sending multicast services to the terminal device in a non-connected state, it is not necessary to send indication information, which can reduce signaling waste.

[0047] In one possible design, the method further includes: when establishing or modifying the Xn interface with the first network device, sending capability information of the second network device to the first network device; or, sending a terminal device context migration request message to the first network device, the terminal device context migration request message including the capability information of the second network device. Alternatively, the operation maintenance management configuration information includes the capability information of the second network device.

[0048] The capability information includes whether to support sending multicast services to terminal devices in a non-connected state.

[0049] In this design, when the Xn interface between the first network device and the second network device is established or modified, the capability information of the second network device is determined, and the capability information of the second network device can be obtained by using the control plane message or user plane message of the Xn interface, thereby reducing signaling overhead. The first network device determines the capability information of the second network device based on the terminal device context migration request message from the second network device, and the capability information of the second network device can be obtained by using the terminal device context migration request message, thereby reducing signaling overhead. The capability information of the second network device is synchronized to the first network device by using OAM configuration information, without using other messages, thereby reducing signaling overhead.

[0050] In one possible design, the receiving of the indication information from the first network device includes: receiving a terminal device context migration response message corresponding to the terminal device sent from the first network device, the terminal device context migration response message including the indication information; or, receiving a paging message sent from the first network device, the paging message including the indication information.

[0051] In this design, the first network device sends indication information to the second network device through the terminal device context migration response message to indicate whether the terminal device needs to be MRB reconfigured. The indication information can be sent using existing messages, which can save signaling overhead and reduce implementation costs.

[0052] In a seventh aspect, the present application provides a communication device that can be applied to a second network device, and the device has the function of implementing the method described in the sixth aspect. The function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the functions of the method described in the sixth aspect, for example, a receiving unit, a sending unit, etc.

[0053] Among them, the receiving unit is used to receive indication information from the first network device, the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device, and the terminal device is a terminal device joining the multicast session; the sending unit is used to send the reconfigured multicast broadcast radio bearer to the terminal device when the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0054] In one possible design, when the terminal device is released to a non-connected state to receive multicast services, the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device; or, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device.

[0055] In one possible design, the indication information is specifically used to indicate whether the terminal device is released to a non-connected state to receive multicast services; or, the indication information is specifically used to indicate that the terminal device is released to a non-connected state to receive multicast service information; or, the indication information includes: suspension configuration information, and the suspension configuration information is used to indicate that the terminal device is released to a non-connected state to receive multicast service information.

[0056] When the indication information indicates that the terminal device is released to a non-connected state to receive multicast services, the sending unit is specifically configured to send a multicast broadcast radio bearer reconfigured for all multicast services of the terminal device to the terminal device.

[0057] Alternatively, when the indication information indicates that the terminal device is released to a non-connected state to receive multicast service information, or the indication information includes suspension configuration information, the sending unit is specifically used to send a multicast broadcast radio bearer reconfigured for the terminal device to be released to a connected state to receive multicast service to the terminal device.

[0058] In one possible design, the indication information includes a wireless resource control connection release message, and the wireless resource control connection release message includes suspension configuration information.

[0059] In one possible design, the second network device supports sending multicast services to non-connected terminal devices.

[0060] In a possible design, the sending unit is further used to send the capability information of the second network device to the first network device when the Xn interface between the first network device and the second network device is established or modified; or, to send a terminal device context migration request message to the first network device, wherein the terminal device context migration request message includes the capability information of the second network device. Alternatively, the operation maintenance management configuration information includes the capability information of the second network device.

[0061] The capability information includes whether to support sending multicast services to terminal devices in a non-connected state.

[0062] In one possible design, the receiving unit is specifically used to receive a terminal device context migration response message corresponding to the terminal device sent from the first network device, the terminal device context migration response message including indication information; or, to receive a paging message sent from the first network device, the paging message including indication information.

[0063] In an eighth aspect, the present application also provides a communication device, comprising: a processor, configured to execute computer instructions stored in a memory, wherein when the computer instructions are executed, the device executes the method described in the sixth aspect or any possible design of the sixth aspect.

[0064] In the ninth aspect, the present application also provides a communication device, including: a processor and an interface circuit, the processor is used to communicate with other devices through the interface circuit, and execute the method described in the sixth aspect or any possible design of the sixth aspect.

[0065] The communication devices described in the seventh to ninth aspects above can be applied to network devices, such as a second network device.

[0066] In the tenth aspect, the present application also provides a computer-readable storage medium, including: computer software instructions; when the computer software instructions are executed in a network device or in a chip built into the network device, the network device executes the method described in the sixth aspect or any possible design of the sixth aspect.

[0067] It can be understood that the beneficial effects that can be achieved by the seventh to tenth aspects provided above can refer to the beneficial effects in the sixth aspect and any possible design thereof, and will not be repeated here.

[0068] In an eleventh aspect, the present application provides a communication method that can be applied to a terminal device, such as a terminal device that joins a multicast session. The method includes: receiving a radio resource control release message from a first network device, the radio resource control release message is used to instruct the terminal device to release to a non-connected state; and sending an indication message to a second network device, the indication message is used to indicate whether it is necessary to reconfigure a multicast broadcast radio bearer for the terminal device.

[0069] The method sends indication information to the second network device through the terminal device, indicating whether the second network device needs to reconfigure the MRB for the terminal device joining the multicast session. This allows the second network device to clearly know whether the MRB needs to be reconfigured for the terminal device when the terminal device accesses, providing the second network device with a decision-making basis for reconfiguring the MRB.

[0070] In one possible design, the indication information includes resident cell information of the terminal device, and the resident cell information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0071] In this design, the resident cell information of the terminal device can be used as indication information to indicate to the second network device whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device. The resident cell information of the terminal device is used to indicate to the second network device whether it is necessary to reconfigure the multicast broadcast radio bearer. The terminal device does not need to make a decision on whether to reconfigure the MRB. The terminal device only provides the decision basis to the second network device.

[0072] In one possible design, the resident cell information includes information of all cells where the terminal device has resided. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether all the cells where the terminal device has resided are synchronized with the packet data convergence protocol. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether the last cell where the terminal device has resided is synchronized with the packet data convergence protocol. When the last cell where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0073] The terminal device may only report whether it has experienced an unsynchronized cell to instruct the second network device whether to reconfigure the multicast broadcast radio bearer for the terminal device. This method saves more signaling and leaves the complexity to the terminal device.

[0074] In one possible design, the sending of indication information to the second network device includes: sending a wireless resource control recovery request message to the second network device, the wireless resource control recovery request message including the indication information; and / or, sending a wireless resource control recovery completion message to the second network device, the wireless resource control recovery completion message including the indication information.

[0075] In this design, the indication information can be sent via a wireless resource control recovery request message and / or a wireless resource control recovery completion message. The existing wireless resource control recovery request message and / or wireless resource control recovery completion message can be used to indicate to the second network device whether it is necessary to reconfigure the multicast broadcast wireless bearer for the terminal device, thereby saving signaling overhead and reducing implementation costs.

[0076] In one possible design, the method further includes: receiving a multicast broadcast radio bearer reconfigured for the terminal device from the second network device.

[0077] In a twelfth aspect, the present application provides a communication device having the function of implementing the method described in the eleventh aspect. The function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the functions of the method described in the eleventh aspect, for example, a receiving unit, a sending unit, etc.

[0078] Among them, the receiving unit is used to receive a wireless resource control release message from the first network device, the wireless resource control release message is used to instruct the terminal device to release to a non-connected state, and the terminal device is a terminal device that joins the multicast session; the sending unit is used to send an indication message to the second network device, and the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast wireless bearer for the terminal device.

[0079] In one possible design, the indication information includes resident cell information of the terminal device, and the resident cell information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0080] In one possible design, the resident cell information includes information of all cells where the terminal device has resided. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether all the cells where the terminal device has resided are synchronized with the packet data convergence protocol. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether the last cell where the terminal device has resided is synchronized with the packet data convergence protocol. When the last cell where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0081] In one possible design, the sending unit is specifically used to send a wireless resource control recovery request message to the second network device, the wireless resource control recovery request message includes indication information; and / or, send a wireless resource control recovery completion message to the second network device, the wireless resource control recovery completion message includes indication information.

[0082] In one possible design, the receiving unit is further used to receive a multicast broadcast radio bearer reconfigured for the terminal device from the second network device.

[0083] In the thirteenth aspect, the present application also provides a communication device, comprising: a processor, for executing computer instructions stored in a memory, when the computer instructions are executed, so that the device executes the method described in the eleventh aspect or any possible design of the eleventh aspect.

[0084] In a fourteenth aspect, the present application also provides a communication device, comprising: a processor and an interface circuit, the processor being used to communicate with other devices through the interface circuit and execute the method described in the eleventh aspect or any possible design of the eleventh aspect.

[0085] The communication apparatus described in the above aspects 12 to 14 can be applied to terminal devices, such as terminal devices that join a multicast session.

[0086] In the fifteenth aspect, the present application also provides a computer-readable storage medium, including: computer software instructions; when the computer software instructions are executed in a terminal device or in a chip built into the terminal device, the terminal device executes the method described in the eleventh aspect or any possible design of the eleventh aspect.

[0087] It can be understood that the beneficial effects that can be achieved by the twelfth to fifteenth aspects provided above can refer to the beneficial effects in the eleventh aspect and any possible design thereof, and will not be repeated here.

[0088] In a sixteenth aspect, the present application provides a communication method that can be applied to a second network device. The method includes: receiving indication information from a terminal device, the terminal device is a terminal device that joins a multicast session, and the indication information is used to indicate whether a multicast broadcast radio bearer needs to be reconfigured for the terminal device; when the indication information indicates that a multicast broadcast radio bearer needs to be reconfigured for the terminal device, sending a reconfigured multicast broadcast radio bearer to the terminal device.

[0089] The method sends indication information to the second network device through the terminal device, indicating whether the second network device needs to reconfigure the MRB for the terminal device joining the multicast session. This allows the second network device to clearly know whether the MRB needs to be reconfigured for the terminal device when the terminal device accesses, providing the second network device with a decision-making basis for reconfiguring the MRB.

[0090] In one possible design, the indication information includes resident cell information of the terminal device, and the resident cell information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0091] In this design, the resident cell information of the terminal device can be used as indication information to indicate to the second network device whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device. The resident cell information of the terminal device is used to indicate to the second network device whether it is necessary to reconfigure the multicast broadcast radio bearer. The terminal device does not need to make a decision on whether to reconfigure the MRB. The terminal device only provides the decision basis to the second network device.

[0092] In one possible design, the resident cell information includes information of all cells where the terminal device has resided. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether all the cells where the terminal device has resided are synchronized with the packet data convergence protocol. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether the last cell where the terminal device has resided is synchronized with the packet data convergence protocol. When the last cell where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0093] The terminal device may only report whether it has experienced an unsynchronized cell to instruct the second network device whether to reconfigure the multicast broadcast radio bearer for the terminal device. This method saves more signaling and leaves the complexity to the terminal device.

[0094] In one possible design, the receiving of indication information from the terminal device includes: receiving a wireless resource control recovery request message from the terminal device, the wireless resource control recovery request message including indication information; and / or receiving a wireless resource control recovery completion message from the terminal device, the wireless resource control recovery completion message including indication information.

[0095] In this design, the indication information can be sent via a wireless resource control recovery request message and / or a wireless resource control recovery completion message. The existing wireless resource control recovery request message and / or wireless resource control recovery completion message can be used to indicate to the second network device whether it is necessary to reconfigure the multicast broadcast wireless bearer for the terminal device, thereby saving signaling overhead and reducing implementation costs.

[0096] In a seventeenth aspect, the present application provides a communication device that can be applied to a second network device, and the device has the function of implementing the method described in the sixteenth aspect. The function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the functions of the method described in the sixteenth aspect, for example, a receiving unit, a sending unit, etc.

[0097] Among them, the receiving unit is used to receive indication information from a terminal device, the terminal device is a terminal device joining a multicast session, and the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; the sending unit is used to send the reconfigured multicast broadcast radio bearer to the terminal device when the indication information indicates that the multicast broadcast radio bearer for the terminal device needs to be reconfigured.

[0098] In one possible design, the indication information includes resident cell information of the terminal device, and the resident cell information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0099] In one possible design, the resident cell information includes information of all cells where the terminal device has resided. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether all the cells where the terminal device has resided are synchronized with the packet data convergence protocol. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether the last cell where the terminal device has resided is synchronized with the packet data convergence protocol. When the last cell where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0100] In one possible design, the receiving unit is specifically used to receive a wireless resource control recovery request message from a terminal device, the wireless resource control recovery request message including indication information; and / or, to receive a wireless resource control recovery completion message from the terminal device, the wireless resource control recovery completion message including indication information.

[0101] In the eighteenth aspect, the present application also provides a communication device, comprising: a processor, for executing computer instructions stored in a memory, when the computer instructions are executed, so that the device executes the method described in the sixteenth aspect or any possible design of the sixteenth aspect.

[0102] In the nineteenth aspect, the present application also provides a communication device, comprising: a processor and an interface circuit, the processor being used to communicate with other devices through the interface circuit and execute the method described in the sixteenth aspect or any possible design of the sixteenth aspect.

[0103] The communication devices described in the seventeenth to nineteenth aspects above can be applied to network devices, such as a second network device.

[0104] In the twentieth aspect, the present application also provides a computer-readable storage medium, including: computer software instructions; when the computer software instructions are executed in a network device or in a chip built into the network device, the network device executes the method described in the sixteenth aspect or any possible design of the sixteenth aspect.

[0105] It can be understood that the beneficial effects that can be achieved by the seventeenth to twentieth aspects provided above can be referred to the beneficial effects in the sixteenth aspect and any possible design thereof, and will not be repeated here.

[0106] In a twenty-first aspect, the present application further provides a communication device, comprising: a transceiver unit and a processing unit. The transceiver unit can be used to send and receive information, or to communicate with other network elements. The processing unit can be used to process data. For example, the device can implement the method described in the first aspect and any possible design thereof, or the method described in the sixth aspect and any possible design thereof, or the method described in the eleventh aspect and any possible design thereof, or the method described in the sixteenth aspect and any possible design thereof, through the transceiver unit and the processing unit.

[0107] In aspect 22, the present application also provides a computer program product, which, when executed, can implement the method described in aspect 1 and any possible design thereof, or the method described in aspect 6 and any possible design thereof, or the method described in aspect 11 and any possible design thereof, or the method described in aspect 16 and any possible design thereof.

[0108] In a twenty-third aspect, the present application further provides a chip system, which is applied to a network device; the chip system includes one or more interface circuits and one or more processors; the interface circuit and the processor are interconnected by a line; the processor receives and executes computer instructions from the memory of the electronic device through the interface circuit to implement the method described in the first aspect and any possible design thereof, or the method described in the sixth aspect and any possible design thereof, or the method described in the sixteenth aspect and any possible design thereof. The network device may be a first network device or a second network device.

[0109] In the twenty-fourth aspect, the present application also provides a chip system, which is applied to a terminal device; the chip system includes one or more interface circuits and one or more processors; the interface circuit and the processor are interconnected through lines; the processor receives and executes computer instructions from the memory of the electronic device through the interface circuit to implement the method described in the eleventh aspect and any possible design thereof.

[0110] In the twenty-fifth aspect, the present application also provides a communication system, including: a first network device and a second network device; the first network device executes the method described in the first aspect or any possible design of the first aspect; the second network device executes the method described in the sixth aspect or any possible design of the sixth aspect.

[0111] In the twenty-sixth aspect, the present application also provides a communication system, including: a terminal device and a second network device; the terminal device executes the method described in the eleventh aspect or any possible design of the eleventh aspect; the second network device executes the method described in the sixteenth aspect or any possible design of the sixteenth aspect.

[0112] It can be understood that the beneficial effects that can be achieved in the twenty-first to twenty-sixth aspects provided above can refer to the beneficial effects described in the first, sixth, eleventh, sixteenth aspects, etc., and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0113] Figure 1 A schematic diagram of the composition of an MBS service transmission architecture is shown;

[0114] Figure 2 A schematic diagram of multicast data transmission is shown;

[0115] Figure 3 A schematic diagram showing the composition of a communication system provided by an embodiment of the present application is shown;

[0116] Figure 4 A schematic diagram showing the composition of a network device provided in an embodiment of the present application is shown;

[0117] Figure 5 A schematic diagram showing a flow chart of a communication method provided in an embodiment of the present application is shown;

[0118] Figure 6 Another schematic diagram of the communication method provided by the embodiment of the present application is shown;

[0119] Figure 7 Another schematic diagram of a communication method according to an embodiment of the present application is shown;

[0120] Figure 8 Another schematic diagram of a communication method according to an embodiment of the present application is shown;

[0121] Fig. 9 Another schematic diagram of a communication method according to an embodiment of the present application is shown;

[0122] Fig.10 Another schematic diagram of a communication method according to an embodiment of the present application is shown;

[0123] Fig.11 Another schematic diagram of a communication method according to an embodiment of the present application is shown;

[0124] Fig.12 Another schematic diagram of a communication method according to an embodiment of the present application is shown;

[0125] Fig.13 A schematic diagram showing the structure of a communication device provided in an embodiment of the present application is shown;

[0126] Fig.14 Another schematic diagram of the structure of the communication device provided in the embodiment of the present application is shown;

[0127] Fig.15 Another structural schematic diagram of a communication device provided in an embodiment of the present application is shown;

[0128] Fig.16 Another structural schematic diagram of a communication device provided in an embodiment of the present application is shown;

[0129] Fig.17 Another structural schematic diagram of the communication device provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0130] A multicast service is a method of transmitting service data to multiple terminal devices in a multicast group in a multicast manner. The terminal device may also be referred to as a user equipment (UE). In an example, the multicast service may be a multicast and broadcast service (MBS). For example, an MBS service may be a live broadcast service, a public safety service, a batch software update service, etc. The MBS service may come from a data server, that is, the data server may provide multicast data. The UE receiving the multicast data may include at least one.

[0131] For example, Figure 1 A schematic diagram of the MBS service transmission architecture is shown. Figure 1 As shown, the MBS service transmission architecture may include: UE 110 , base station 120 , core network equipment 130 , and data server 140 .

[0132] The data server 140 may send multicast service data (or MBS data, or simply multicast data) to the core network device 130. The core network device 130 may send the received MBS data to the base station 120. The base station 120 may send the MBS data to at least one UE 110 receiving the MBS service.

[0133] When the core network device 130 sends MBS data to the base station 120, the data may be transmitted through a common transmission channel MBS session, and each MBS session may include at least one MBS quality of service (QoS) flow.

[0134] When the base station 120 sends MBS data to the UE 110, the data can be transmitted through an MBS radio bearer. The MBS radio bearer can also be referred to as an MRB. There are two transmission modes for an MBS radio bearer: one can use a point to multi-point (PTM) transmission mode; the other can use a point to point (PTP) transmission mode.

[0135] Take sending multicast data to UE1 and UE2 as an example. Figure 2 FIG. 1 shows a schematic diagram of multicast data transmission. Figure 2 As shown, the provider of multicast data (i.e., the content provider shown in the figure, such as the above-mentioned data server 140) can transmit multicast data to the core network (CN). The core network can perform group management, such as maintaining UE1 and the multicast group to which UE1 belongs. The core network can manage the joining and exiting of UEs. The core network and the radio access network (RAN) can establish relevant multicast sessions based on protocol data unit (PDU) session related signaling, and can also transmit information about UE joining and exiting MBS sessions. RAN can include base stations. For example, PDU session for UE1, PDU session for UE2, etc. In other words, multicast data transmission between the core network and the base station can rely on PDU session, introducing a new multicast QoS flow (MBS QoS flow).

[0136] RAN can support PTP and PTM transmission modes to send multicast data to UE1 or UE2, and support dynamic switching between PTP and PTM controlled by RAN. For example, RAN can send data to UE1 and UE2 respectively in PTP mode based on cell radio network temporary identifier (C-RNTI), and can also send multicast data to UE1 and UE2 in PTM mode based on group radio network temporary identifier (G-RNTI).

[0137] In the 5G new radio (NR), the UE can have three radio resource control (RRC) states, namely: RRC connected state, RRC idle state, and RRC inactive state. Among them, the RRC connected state (hereinafter referred to as the connected state) can also be called the RRC active state or the RRC active state. The RRC inactive state can also be called the RRC inactive state (hereinafter referred to as the inactive state). Relative to the RRC connected state, the RRC idle state and / or the RRC inactive state can be called the RRC non-connected state (hereinafter referred to as the non-connected state).

[0138] After the UE establishes an RRC connection with a network device (such as a base station), the UE enters the RRC connected state. If the UE has no need to transmit data with the network device within a preset time period in the RRC connected state, the network device may determine that the UE enters the RRC inactive state, and the network device may send an RRC release (RRCRelease with suspend indication) message carrying a suspension indication to the UE. After the UE receives the RRCRelease with suspend indication message, the UE retains its own context and enters the RRC inactive state. In the RRC inactive state, the UE can save the UE context information, but temporarily disconnects the RRC connection with the network device. When the UE has data to transmit, the UE can send an RRC recovery request message to the network device, and the network device can send an RRC recovery response message to the UE. After receiving the recovery response message, the UE can send an RRC recovery completion message to the network device, and the UE enters the RRC connected state and resumes using the UE context.

[0139] Alternatively, when the UE is in the RRC connected state, the network device may also send an RRC release message to the UE, and the UE may release the RRC connection with the network device and enter the RRC idle state. When the UE is in the RRC idle state, the UE may send an RRC establishment request message to the network device, and the network device may establish an RRC connection with the UE based on the RRC establishment request message, so that the UE may enter the RRC connected state.

[0140] It can be understood that, compared with entering the RRC connected state from the RRC idle state, the UE enters the RRC connected state faster from the RRC inactive state.

[0141] A UE in RRC inactive state can move within the RNA range and restore the RRC connection in cells of other access network devices within the RNA range. The cell where the UE restores the RRC connection is generally called a new cell or a target cell.

[0142] Currently, in the scenario of multicast data transmission, UE can receive multicast data in RRC connected state, that is, multicast service can only be provided to UE in RRC connected state, and the base station and core network need to maintain the UE information corresponding to the multicast group. In addition, multicast service also supports multicast session deactivation / activation triggered by the core network, and UE does not perceive the service status.

[0143] However, when the number of multicast users (i.e., the number of UEs) in a cell is too large, it may exceed the number of connected UEs that the cell can accommodate. For example, in some concerts, stadiums, or other public safety scenarios with dense users, there may be too many multicast users (i.e., the number of UEs) in a cell, exceeding the number of connected UEs that the cell can accommodate, causing network congestion and affecting user service experience.

[0144] In order to alleviate network congestion, the base station can support UEs joining a multicast session to receive multicast services in a non-connected state (such as an inactive state). Non-connected UEs can use PTM to receive multicast sessions according to the multicast configuration (or multicast PTM configuration) provided by a network device (such as a base station). For a multicast session, the multicast PTM configuration for non-connected UEs to receive multicast services may include one or more of the following: an identifier of the multicast session (such as TMGI), a multicast MRB configuration, a G-RNTI for descrambling the multicast multicast service channel (MBS traffic channel, MTCH), multicast MTCH scheduling information, etc.

[0145] The multicast MRB configuration may include packet data convergence protocol (PDCP) configuration, radio link control (RLC) configuration, etc. of the multicast MRB.

[0146] PCDP configuration includes configuring the PDCP entity and configuring PDCP parameters. The PDCP entity can be responsible for data compression and decompression, as well as security protection. PDCP parameters can include the length of the PDCP sequence number (SN), the size of the PDCP PDU, the PDCP retransmission timer, etc.

[0147] RLC configuration includes configuring RLC entities and configuring RLC parameters. RLC entities are responsible for data segmentation and reassembly, as well as data transmission control. RLC parameters include RLC mode, RLC SN length, RLC PDU size, RLC retransmission timer, etc.

[0148] The network side can determine the configuration parameters of PDCP and RLC based on network requirements and service requirements.

[0149] The reason why the UE is released to the non-connected state may be due to service deactivation, or it may be released to the non-connected state to receive multicast services due to network congestion as mentioned above. When the UE accesses the new cell from the old cell, and the base station corresponding to the new cell (which may be called the new base station) is different from the base station corresponding to the old cell (which may be called the old base station), if the UE is released to the non-connected state due to service deactivation, the new base station may not reconfigure the MRB or perform MRB incremental configuration. If the UE is released to the non-connected state to receive multicast services due to network congestion, the MRBs of the new and old cells may be different, or the UE continues to use the MRB to receive data in the non-connected state, resulting in the MRB configuration in the UE may change. The new cell is not sure whether the MRB configuration on the UE side has changed, whether the UE can continue to use the MRB used in the old cell in the new cell, or the MRB configuration stored on the UE side cannot be determined. The new base station needs to reconfigure the MRB.

[0150] Reconfiguring the MRB may include: sending the PDCP configuration of the MRB, and / or the RLC configuration, and / or the MAC configuration, and / or the physical layer (PHY) configuration to the UE. Alternatively, instructing the release of the MRB and then creating a new MRB. Alternatively, instructing the PDCP entity of the MRB to be rebuilt, or resetting the PDCP entity, and / or the RLC entity, and / or the MAC entity, and / or the physical layer entity for the UE.

[0151] Exemplarily, in one implementation, the MRB reconfiguration may be performed in a full configuration manner. For example, PDCP configuration, RLC configuration, MAC configuration, and PHY configuration may be sent to the UE, and each configuration is full configuration information.

[0152] In another implementation, the MRB reconfiguration can be performed in a deletion and re-establishment manner, instructing the UE to delete the original MRB configuration information, and sending new PDCP configuration, RLC configuration, MAC configuration, and PHY configuration to the UE, each of which is full configuration information.

[0153] In another implementation, MRB reconfiguration may also be performed in a PDCP reestablishment manner, for example, the UE may be instructed to reestablish the PDCP entity and perform PDCP configuration. In this manner, RLC configuration, MAC configuration and PHY configuration may or may not be reconfigured, and are not limited here.

[0154] Not reconfiguring the MRB may include: not sending the PDCP configuration of the MRB, and / or the RLC configuration, and / or the MAC configuration, and / or the physical layer (PHY) configuration to the UE, or performing MRB incremental configuration on the UE. Alternatively, not indicating the release of the MRB and then creating a new MRB. Alternatively, not indicating the PDCP entity reconstruction of the MRB. Alternatively, not resetting the PDCP entity, and / or the RLC entity, and / or the MAC entity, and / or the physical layer entity for the UE.

[0155] Exemplarily, the UE may not be instructed to delete the original MRB configuration information, nor may a new PDCP configuration, RLC configuration, MAC configuration, or PHY configuration be sent to the UE. Alternatively, the UE may not be instructed to reestablish the PDCP entity. When the UE is not instructed to reestablish the PDCP entity, the RLC configuration, MAC configuration, and PHY configuration may or may not be reconfigured, and this is not limited here.

[0156] However, the new base station cannot distinguish the reason why the UE is released to the non-connected state, and thus cannot decide whether to reconfigure the MRB for the UE.

[0157] Exemplarily, after a UE joins a multicast session in a cell, the UE may move and may need to reselect or switch cells. The current cell to which the UE is connected may be referred to as an old cell, or a source cell, or a previous resident cell, and the cell after the UE reselects may be referred to as a new cell, or a target cell, or a new resident cell. The base station corresponding to the old cell may be referred to as an old base station, or a source base station, and the base station corresponding to the new cell may be referred to as a new base station, or a target base station. When the UE is released to a non-connected state in the old cell, and the new base station is different from the old base station, the new base station cannot distinguish the reason why the UE is released to a non-connected state, and thus cannot decide whether the UE needs to be reconfigured with MRB.

[0158] In addition, currently, for the scenario where the new base station does not support sending multicast services to non-connected UEs, if the new base station is an R17 base station, when the new base station receives access from a UE that receives multicast services in a non-connected state, it will not reconfigure the MRB (for example, it will not modify the PDCP part of the MRB configuration, as described above). Once the UE's previous cell is an unsynchronized cell, the hyper frame number (HFN) part of the UE's PDCP window variable will be reset, for example, to 0. When the new base station enters the connected state, if the PDCP window variable is not reset again, the MRB data received again will determine a count value that is inconsistent with the count value on the network side, that is, an unsynchronized COUNT value may be generated. Based on the inconsistent count value, the UE may discard data packets or erroneously deliver data packets, causing data confusion and affecting the effect of the UE receiving services. In addition, the MRB configuration information in the context obtained by the new base station based on the UE context migration process is still configured by the network for the UE when the old base station is used. If the new base station performs incremental configuration based on this configuration, all MRB configurations of the UE will cause problems, resulting in inconsistent understanding with the UE.

[0159] To this end, an embodiment of the present application provides a communication method, which can be applied to a communication system, and the communication system may include: a first network device, a terminal device, and a second network device. The method may include: the first network device sends a radio resource control release message to a terminal device that joins a multicast session, and the radio resource control release message is used to indicate that the terminal device is released to a non-connected state; the first network device sends indication information to the second network device, and the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device. The second network device can receive the indication information from the first network device; when the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device, the second network device can send the reconfigured multicast broadcast radio bearer to the terminal device.

[0160] This method can be used to enable the first network device to indicate to the second network device whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device released to the non-connected state. The second network device can decide whether to reconfigure the multicast broadcast radio bearer for the terminal device released to the non-connected state according to the instruction of the first network device.

[0161] The communication method provided in the embodiments of the present application is exemplarily described below with reference to the accompanying drawings.

[0162] It should be noted that, in the description of the present application, the words "first", "second", etc. are only used to distinguish the description and are not used to specifically limit a certain feature. In the description of the embodiments of the present application, "and / or" describes the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. At least one referred to in this application refers to one or more; multiple refers to two or more. The embodiments of the present application may only execute fewer steps than all the steps, or execute more steps, without limitation.

[0163] For example, Figure 3 FIG. 1 is a schematic diagram showing the composition of a communication system provided by an embodiment of the present application. Figure 3 As shown, the communication system may include at least one terminal device 310 and at least two network devices 320 .

[0164] Among them, the network device 320 can also be called a wireless access network device or a next-generation wireless access network device, such as a base station. The terminal device 310 can communicate with the network device 320. The network device 320 can provide the terminal device with functional services such as wireless resource management, service quality management, data encryption and compression. Different network devices 320 can communicate through the Xn interface. Different terminal devices 310 can exchange information and communicate through the network device 320.

[0165] The terminal device 310 is located within the coverage of one or more cells (carriers) provided by the network device 320, and there may be one or more cells serving the terminal device 310. When there are multiple serving cells for the terminal device 310, the terminal device 310 may operate in CA, dual connectivity (DC), or coordinated multi-point transmission mode.

[0166] In the communication system, the terminal device 310 can receive a multicast service in a cell corresponding to a certain network device 320, such as a first network device. The first network device can also release the terminal device 310 to a non-connected state to receive a multicast service, or release the terminal device 310 to a non-connected state due to service deactivation. The terminal device 310 can reselect or switch a cell and reselect to another network device 320, such as a cell corresponding to a second network device. The terminal device 310 (UE) described herein is released to a non-connected state to receive a multicast service, and the non-connected state may refer to an inactive state.

[0167] In the embodiment of the present application, taking the network device 320 as a base station as an example, the first network device can be called a source base station (anchor base station), an old base station, an old base station, a released base station, a base station that releases the UE connection state, a base station that the UE last serves, or a base station that is last used, etc. The second network device can be called a target base station, a new base station, a newly accessed base station, a base station that the UE newly serves, or a newly used base station, etc. The present application does not limit the specific names of the network devices 320 that correspond to the terminal device before and after the cell reselection.

[0168] Optionally, the communication system can be a wideband code division multiple access (WCDMA) system, a long term evolution (LTE) system, an advanced long term evolution LTE-A (LTE advanced) system, an LTE frequency division duplex (FDD) system, a universal mobile telecommunication system (UMTS), a 5G NR system, and other wireless communication systems that apply OFDM technology, etc. This application does not limit the specific type of the communication system.

[0169] For example, when the communication system is a 5G NR system, the communication system may also include a core network device, and the core network device and the network device 320 may communicate via a next generation (NG) interface.

[0170] Optionally, the terminal device 310 in the communication system may also be referred to as user equipment (UE), mobile station (MS), mobile terminal (MT), etc. The terminal device 310 may refer to a device that provides voice and / or data connectivity to a user, for example, a mobile phone (“cellular” phone), a mobile phone, a computer, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a laptop computer, a handheld communication device, a handheld computing device, a satellite wireless device, a wireless modem card, a TV set top box (STB), a customer premises equipment (CPE), a wearable device (such as a smart watch, a smart bracelet, a pedometer, etc.), an in-vehicle device (such as a car, a bicycle, an electric car, an airplane, a ship, a train, a high-speed train, etc.), a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a smart home device (such as a refrigerator, a TV, an air conditioner, an electric meter, etc.), an intelligent robot, a workshop device, a wireless terminal in self-driving, a remote medical The terminal device 310 may include wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, flying equipment (for example, intelligent robots, hot air balloons, drones, airplanes), and other devices for communicating on wireless systems, such as other MTC terminals in IoT, etc. The present application does not limit the specific form of the terminal device 310.

[0171] The network device 320 may be an access network device of the communication system, such as a base station. Optionally, in the embodiment of the present application, the network device 320 may include various forms of macro base stations, micro base stations (also called small stations), etc. For example, the network device may include: a base station in the aforementioned WCDMA or LTE, a next generation base station (next generation nodeB, gNB), a next generation evolved nodeB (ng-eNB), a transmission reception point (transmission reception point, TRP), an evolved Node B (evolved Node B, eNB), a radio network controller (radio network controller, RNC), a Node B (Node B, NB), a base station controller (base station controller, BSC), a base transceiver station (base transceiver station, BTS), a home base station (for example, home evolved NodeB, or home Node B, HNB), a base band unit (base band unit, BBU), or a wireless fidelity (wireless fidelity, Wifi) access point (access point, AP), etc.

[0172] It is understandable that the aforementioned communication system is only for the purpose of more clearly illustrating the technical solution of the embodiment of the present application, and does not constitute a limitation on the technical solution provided by the embodiment of the present application. For example, the communication system may also include other devices, such as: a network control device. The network control device may be an operation administration and maintenance (OAM) system, also known as a network management system. The network control device may manage the aforementioned network devices.

[0173] Corresponding to the communication system, the network device 320 described in the embodiment of the present application can be a base station system based on the fourth generation mobile information technology (the 4th generation mobile communication technology, 4G), or a base station system based on the fifth generation mobile information technology (the 5th generation mobile communication technology, 5G), or a base station system based on the sixth generation mobile information technology (the 6th generation mobile communication technology, 6G), and may even be suitable for base station systems or fronthaul networks in future communication networks in the future, without specific limitation.

[0174] For example, Figure 4 FIG. 1 shows a schematic diagram of a network device provided in an embodiment of the present application. The network device may be the first network device or the second network device. Figure 4 As shown, the network device may include: at least one processor 41 , a memory 42 , a communication interface 43 , and a bus 44 .

[0175] The processor 41 is the control center of the network device, which can be a processor or a general term for multiple processing elements. For example, the processor 41 can be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application, such as one or more microprocessors (digital signal processors, DSPs), or one or more field programmable gate arrays (FPGAs).

[0176] The processor 41 can execute various functions of the network device by running or executing the software program stored in the memory 42, and calling the data stored in the memory 42. For example, when the network device is a first network device, the steps performed by the first network device in the communication method provided in the embodiment of the present application can be executed. For another example, when the network device is a second network device, the steps performed by the second network device in the communication method provided in the embodiment of the present application can be executed.

[0177] In a specific implementation, as an embodiment, the processor 41 may include one or more CPUs, such as Figure 4CPU0 and CPU1 are shown in the figure.

[0178] In a specific implementation, as an embodiment, the network device may include multiple processors, such as Figure 4 41 and processor 45 are shown in FIG. Each of these processors may be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). A processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0179] The memory 42 can store the software program of the method steps executed by the network device, and the execution is controlled by the processor 41. The memory 42 can be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0180] The memory 42 may exist independently and be connected to the processor 41 via the bus 44. Alternatively, the memory 42 may be integrated with the processor 41, which is not limited here.

[0181] The communication interface 43 uses any transceiver or other device for communicating with other devices or communication networks. The communication interface 43 may be an Ethernet interface, a radio access network (RAN) interface, a wireless local area network (WLAN) interface, etc. The communication interface 43 may include a receiving unit to implement a receiving function, and a sending unit to implement a sending function.

[0182] The bus 44 may be an industry standard architecture (ISA) bus, a peripheral component interconnect (PCI) bus, or an extended industry standard architecture (EISA) bus. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 4 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0183] Although attached Figure 4 The bus 44 is used in the embodiment, but it is understandable that the bus can also be replaced by other forms of connection relationships and is not limited to the bus itself.

[0184] Optionally, the structure of the terminal device described in the embodiment of the present application can also refer to Figure 4 The structure of the network device shown will not be repeated here.

[0185] The communication method provided in the embodiment of the present application can be applied to the above Figure 3 In the communication system shown, a scenario is described in which a first network device releases a terminal device to a non-connected state, and the terminal device reselects or switches a cell and reselects a cell corresponding to a second network device.

[0186] It should be understood that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0187] For example, taking the example that the first network device indicates to the second network device that a multicast broadcast radio bearer needs to be reconfigured for the terminal device, Figure 5 FIG. 1 is a flow chart showing a communication method provided by an embodiment of the present application. Figure 5 As shown, the communication method may include S501-S503.

[0188] S501. A first network device sends a radio resource control release message to a terminal device that has joined a multicast session. The radio resource control release message is used to instruct the terminal device to release to a non-connected state.

[0189] Exemplarily, the terminal device can access the cell corresponding to the first network device, such as cell 1, and join the multicast session to receive the multicast service. For example, the terminal device can receive the multicast service in the connected state. The specific manner in which the terminal device receives the multicast service can refer to the above-mentioned embodiment.

[0190] In some possible scenarios, the first network device can send a radio resource control release message to the terminal device to instruct the terminal device to release to a non-connected state to receive multicast services, such as the network congestion scenario described above. The first network device has the ability to support sending multicast services to non-connected terminal devices.

[0191] In some other possible scenarios, the first network device may also send a radio resource control release message to the terminal device based on the reason for service deactivation, instructing the terminal device to release to a non-connected state. For example, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the first network device may send a radio resource control release message to the terminal device, instructing the terminal device to release to a non-connected state.

[0192] Exemplarily, the radio resource control release message (RRC release) message may instruct the terminal device to enter an inactive state to receive multicast services, or may only instruct the terminal device to enter a non-connected state. When instructing the terminal device to enter an inactive state to receive multicast services, the RRC release message may be the RRC release (RRC release with suspend indication) message mentioned above. For example, the RRC release message may include suspend configuration (suspendConfig) information, and the suspendConfig information is used to instruct the terminal device to enter a non-connected state. When the first network device instructs the terminal device to release to a non-connected state to receive multicast services, the suspendConfig information is also used to indicate the multicast service information that the terminal device is released to receive in a non-connected state. The terminal device in the non-connected state may receive multicast services according to the instructions of the suspendConfig information.

[0193] As mentioned above, a terminal device in a non-connected state can use PTM to receive a multicast session according to the multicast PTM configuration provided by the network device.

[0194] In one possible design, the first network device may send a multicast PTM configuration for a non-connected terminal device to receive a multicast session to the terminal device in an RRC release message. For example, the multicast PTM configuration may be included in the suspendconfig information.

[0195] In another possible design, the first network device may send an MBS control channel (MCCH) message to the UE in a manner similar to providing the MBS broadcast configuration.

[0196] For the case where the MBS broadcast configuration is sent to the terminal device via the MCCH message, the MCCH configuration method can be as follows: 1) The RRC release message can also include the MCCH configuration of the cell, which is used by the terminal device to obtain the MCCH message; 2) The MCCH configuration can also be sent through the cell public signaling, similar to the broadcast, and the MCCH configuration is sent in the system message (such as SIBx). The terminal device obtains the multicast MCCH configuration by reading the system message, and then reads the multicast MCCH message of the cell, and then obtains the multicast PTM configuration through the MCCH message.

[0197] Optionally, if the terminal device has started receiving the multicast session in the connected state. The first network device can instruct the terminal device to use the multicast PTM configuration for receiving the multicast session in the RRC connected state to receive the multicast session in the non-connected state, and can also provide the non-connected multicast PTM configuration through the above-mentioned RRC release message or MCCH message. The non-connected multicast PTM configuration can be the same as the configuration in the connected state, or it can be different from the configuration in the connected state. In some other possible ways, the terminal device can also execute by default to continue to use the multicast PTM configuration in the connected state without the need for network-side instructions.

[0198] The above multicast PTM configuration may also be referred to as MRB configuration, or MRB configuration including only the PTM part.

[0199] After the terminal device is released to the non-connected state, it may perform cell reselection and / or switching and reselect to the cell corresponding to the second network device.

[0200] After the first network device sends the radio resource control release message to the terminal device, S502 may be executed to indicate to the second network device that a multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0201] S502: The first network device sends indication information to the second network device, where the indication information is used to indicate that a multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0202] Correspondingly, the second network device receives the indication information from the first network device.

[0203] Exemplarily, the first network device may instruct the second network device to reconfigure a multicast broadcast radio bearer (MBS radio bearer, MRB) for the terminal device by sending a message including the above instruction information to the second network device. For details of the MRB, please refer to the description in the above embodiments.

[0204] The second network device may execute S503 to reconfigure the MRB for the terminal device according to the instruction of the instruction information. It can be understood that after the terminal device accesses the cell corresponding to the second network device, the second network device executes S503.

[0205] S503: The second network device sends a reconfigured multicast broadcast radio bearer to the terminal device.

[0206] Exemplarily, the second network device reconfigures the MRB for the terminal device, which may include: configuring the MRB in a full configuration (fullconfig) manner, or deleting and then establishing the MRB or rebuilding the MRB. The manner in which the MRB is reconfigured may depend on specific network requirements and service requirements, which are not limited here.

[0207] Among them, configuring the MRB in full config mode means that the second network device can provide complete configuration information for the terminal device, including parameters such as frequency and channel. Exemplarily, the MRB configuration information may include at least one of the parameters of the four layers of PDCP, RLC, MAC, and PHY. Optionally, the MRB configuration information may be carried by messages such as RRC reconfiguration messages and RRC recovery completion messages.

[0208] Deleting and then establishing the MRB means first deleting the original multicast broadcast radio bearer and then re-establishing a new bearer. Optionally, deleting and then establishing the MRB can be achieved through a message such as an RRC reconfiguration message, or two RRC reconfiguration messages, or an RRC recovery complete message and a reconfiguration message, etc., and this application does not limit this.

[0209] Rebuilding the MRB refers to reconfiguring an existing multicast broadcast radio bearer, including changing at least one of the parameters of PDCP, RLC, MAC, PHY, etc. Exemplarily, the UE may be instructed to rebuild the PDCP entity and perform PDCP configuration.

[0210] The specific implementation of the above-mentioned reconfiguration of MRB can also refer to the description in the above-mentioned embodiment.

[0211] Accordingly, the terminal device receives the reconfigured multicast broadcast radio bearer and updates the multicast broadcast radio bearer.

[0212] above Figure 5 The illustrated embodiment introduces a situation where the first network device indicates to the second network device that a multicast broadcast radio bearer needs to be reconfigured for the terminal device. Figure 6 Another flow chart of the communication method provided by the embodiment of the present application is shown. Figure 6As shown, when the first network device indicates to the second network device that there is no need to reconfigure the multicast broadcast radio bearer for the terminal device, the communication method may include S601-S603.

[0213] S601. A first network device sends a radio resource control release message to a terminal device that has joined a multicast session. The radio resource control release message is used to instruct the terminal device to release to a non-connected state.

[0214] S601 may refer to the above-mentioned S501 and will not be described in detail herein.

[0215] S602: The first network device sends indication information to the second network device, where the indication information is used to indicate that there is no need to reconfigure a multicast broadcast radio bearer for the terminal device.

[0216] Correspondingly, the second network device receives the indication information from the first network device.

[0217] Exemplarily, the first network device may send a message including the above indication information to the second network device, thereby indicating that the second network device does not need to reconfigure the MRB for the terminal device.

[0218] The second network device may not perform the operation of reconfiguring the MRB for the terminal device according to the instruction of the instruction information.

[0219] S603: The second network device does not reconfigure the MRB for the terminal device.

[0220] It can be understood that, in actual implementation, there is no actual step in S603, and the second network device does not need to perform the operation of reconfiguring the MRB for the terminal device. Figure 6 For better explanation only, it is indicated by S603. In other words, the second network device just does not rebuild the PDCP entity, and other underlying layers still need to be reconfigured, or it can be incrementally configured. For example, the second network device may not instruct the UE to rebuild the PDCP entity, reconfigure or not reconfigure the RLC configuration, MAC configuration and PHY configuration, or incrementally configure the UE, which is not limited here. The implementation logic of not reconfiguring MRB can also refer to the description in the aforementioned embodiment.

[0221] In the embodiment of the present application, the first network device sends indication information to the second network device, indicating whether the second network device needs to reconfigure the MRB for the terminal device joining the multicast session. This allows the second network device to clearly understand whether the MRB needs to be reconfigured for the terminal device when the terminal device accesses, thereby providing the second network device with a decision-making basis for reconfiguring the MRB.

[0222] Based on the above embodiments, the present application actually provides a communication method applied to a first network device and a communication method applied to a second network device. In the communication method applied to the first network device, the first network device can send a wireless resource control release message to the terminal device that joins the multicast session, and the wireless resource control release message is used to instruct the terminal device to release to a non-connected state; the first network device can send indication information to the second network device, and the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device. In the communication method applied to the second network device, the second network device can receive indication information from the first network device; when the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device, the second network device can send a reconfigured multicast broadcast radio bearer to the terminal device; when the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device, the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device.

[0223] In one possible design, the indication information specifically indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device, or that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device, which can be determined by the reason why the terminal device is released to a non-connected state.

[0224] For example, when the terminal device is released to a non-connected state to receive multicast services, the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device; or, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device.

[0225] Exemplarily, the first network device may know whether the terminal device is released to a non-connected state to receive multicast services or whether the terminal device is released to a non-connected state because the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated. The first network device may indicate to the second network device whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device based on the reason why the terminal device is released to a non-connected state.

[0226] In this design, for the scenario where the terminal device is released to a non-connected state to receive multicast services and access the second network device, the second network device can reconfigure the multicast broadcast radio bearer for the terminal device. For the scenario where the terminal device accesses the second network device after the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated and the terminal device is released to a non-connected state, the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device, thereby reducing part of the signaling overhead.

[0227] In the case where the second network device is a network device that does not support sending multicast services to non-connected UEs, such as the second network device is an R17 base station, after the second network device receives access from a UE that receives multicast services in a non-connected state, the second network device can still reconfigure the MRB, such as modifying the PDCP part in the MRB configuration, which can reduce the occurrence of situations such as MRB data being sent in disorder and MRB configuration problems. Optionally, the second network device and the first network device that supports sending multicast services to non-connected UEs can be synchronized or asynchronous.

[0228] Optionally, in some embodiments, the terminal device may be released to a non-connected state to receive multicast services, the joined multicast session may have no data temporarily, or the multicast session may be deactivated. In response to such a situation, the first network device may treat the situation as if the terminal device is released to a non-connected state to receive multicast services, and send an indication message to the second network device, indicating that the second network device needs to reconfigure the multicast broadcast radio bearer for the terminal device.

[0229] In one possible design, the above indication information can be specifically used to indicate whether the terminal device is released to a non-connected state to receive multicast services.

[0230] Exemplarily, the indication information may indicate whether the terminal device is released to a non-connected state to receive multicast services; after receiving the indication information, the second network device may decide whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device based on the indication result of the indication information. For example, when the indication information indicates that the terminal device is released to a non-connected state to receive multicast services, the second network device may reconfigure the multicast broadcast radio bearer for the terminal device. Alternatively, when the indication information indicates that the terminal device is released to a non-connected state and does not receive multicast services (i.e., it is released to a non-connected state, but does not receive multicast services in the non-connected state), the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device.

[0231] For example, in this design, the indication information can be a 1-bit field, such as an enumeration value of "true", which can indicate whether the terminal device is released to a non-connected state to receive multicast services. This application does not limit the implementation method of the indication information (such as the type or size of the field).

[0232] This design indicates whether the terminal device is released to a non-connected state to receive multicast services through indication information, and can indicate to the second network device whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device with a small signaling overhead. When the second network device reconfigures the multicast broadcast radio bearer for the terminal device, it can perform MRB reconfiguration for all multicast services received by the terminal device.

[0233] When the indication information indicates that the terminal device is released to a non-connected state to receive multicast services, the step of the second network device sending a reconfigured multicast broadcast radio bearer to the terminal device may include: sending a multicast broadcast radio bearer reconfigured for all multicast services of the terminal device to the terminal device.

[0234] In another possible design, the above indication information can be specifically used to indicate that the terminal device is released to a non-connected state to receive multicast service information.

[0235] Exemplarily, the indication information may indicate which multicast services the terminal device has received when it is released to a non-connected state, that is, the received multicast service information. After receiving the indication information, the second network device may decide whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device based on the multicast service information received when the terminal device is released to a non-connected state. For example, when the multicast service information received by the terminal device when it is released to a non-connected state is empty, the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device. When the multicast service information received by the terminal device when it is released to a non-connected state is not empty, such as including the target multicast service, the second network device may reconfigure the multicast broadcast radio bearer for the target multicast service.

[0236] Optionally, in this design, the indication information can be a temporary multicast group identifier (TMGI) list. The TMGI list can indicate which multicast services the UE is released to inactive to receive, and can make it clear to the second network device which multicast services only need to be reconfigured. The second network device can reconfigure the multicast broadcast radio bearer for the multicast services that the terminal device is released to connected to receive.

[0237] When the indication information indicates that the terminal device is released to a non-connected state to receive multicast service information, the step of the second network device sending a reconfigured multicast broadcast radio bearer to the terminal device may include: sending a multicast broadcast radio bearer reconfigured to the terminal device for the multicast service that the terminal device is released to a connected state to receive.

[0238] This design can instruct the second network device to accurately reconfigure the multicast broadcast wireless bearer for the multicast service that the terminal device is released to receive in the connected state through indication information.

[0239] In another possible design, the above indication information can be specifically used to indicate that the terminal device is released to the MRB information used for receiving multicast services in a non-connected state.

[0240] Exemplarily, the indication information may indicate which MRB information (such as an MRB identifier) ​​is used by the terminal device to receive the multicast service when it is released to a non-connected state. After receiving the indication information, the second network device may decide whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device based on the MRB information used by the terminal device to receive the multicast service when it is released to a non-connected state. For example, when the MRB information used by the terminal device to receive the multicast service when it is released to a non-connected state is empty, the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device. When the MRB information used by the terminal device to receive the multicast service when it is released to a non-connected state is not empty, such as including the target MRB, the second network device may reconfigure the multicast broadcast radio bearer for the target MRB.

[0241] This design indicates the MRB information used by the terminal device to be released to the non-connected state for receiving multicast services through indication information, so as to instruct the second network device to more accurately reconfigure the MRB used by the terminal device to be released to the connected state for receiving multicast services.

[0242] In another possible design, the above-mentioned indication information may include: suspension configuration information, and the suspension configuration information is used to indicate that the terminal device is released to a non-connected state to receive multicast service information.

[0243] Exemplarily, referring to the above-mentioned embodiment, the RRC release message may include suspend configuration (suspendConfig) information, and the suspendConfig information is used to instruct the terminal device to enter a non-connected state. When the first network device instructs the terminal device to release to a non-connected state to receive a multicast service, the suspendConfig information is also used to indicate the multicast service information received by the terminal device when it is released to a non-connected state. The terminal device in the non-connected state can receive the multicast service according to the instruction of the suspendConfig information.

[0244] When the indication information includes the suspension configuration information, the suspension configuration information can indicate to the second network device the multicast service information that the terminal device is released to receive in the non-connected state. The second network device can reconfigure the multicast broadcast radio bearer for the multicast service that the terminal device is released to receive in the connected state.

[0245] When the indication information includes suspension configuration information, the step of the second network device sending a reconfigured multicast broadcast radio bearer to the terminal device may include: sending a reconfigured multicast broadcast radio bearer to the terminal device for the multicast service that the terminal device is released to receive in a connected state.

[0246] Exemplarily, the suspendConfig information may also include MRB information used by the terminal device to be released to a non-connected state to receive multicast services. When the indication information includes the suspendConfig information, and the suspendConfig information includes the MRB information used by the terminal device to be released to a non-connected state to receive multicast services, after receiving the indication information, the second network device may reconfigure the MRB used by the terminal device to be released to a non-connected state to receive multicast services according to the MRB information used by the terminal device to be released to a non-connected state to receive multicast services.

[0247] The present design can indicate the multicast service information that the terminal device is released to receive in a non-connected state by suspending configuration information, and / or indicating the MRB information used by the multicast service that the terminal device is released to receive in a non-connected state, and can also instruct the second network device to accurately reconfigure the multicast broadcast radio bearer for the multicast service that the terminal device is released to receive in a connected state.

[0248] In another possible design, the above indication information may also include a radio resource control connection release (RRCrelease) message, and the RRC release message includes suspension configuration information.

[0249] In this design, the first network device can also use the RRC release message as indication information, and indicate to the second network device through the suspension configuration information in the RRC release message that the terminal device is released to the non-connected state to receive the multicast service information. By using the RRC release message as indication information, it is also possible to instruct the second network device to accurately reconfigure the multicast broadcast radio bearer for the multicast service that the terminal device is released to receive in the connected state.

[0250] In some other possible designs, the implementation of the indication information may also include any one or more of the above. In other words, the indication information may be implemented in at least one of the following implementations: indicating whether the terminal device is released to a non-connected state to receive multicast services, indicating that the terminal device is released to a non-connected state to receive multicast service information, including suspension configuration information, and including a radio resource control connection release message.

[0251] For example, the indication information may include: a 1-bit indication field (refer to the above description), a TMGI list, suspendConfig information, and an RRC release message.

[0252] This application does not limit the implementation method of the indication information.

[0253] In a possible design, the first network device may also decide whether to send the above indication information to the second network device based on the capability information of the second network device. The capability information includes whether to support sending multicast services to terminal devices in a non-connected state. When the second network device supports sending multicast services to terminal devices in a non-connected state, the first network device may send indication information to the second network device; or, when the second network device does not support sending multicast services to terminal devices in a non-connected state, the first network device may not send indication information to the second network device.

[0254] For example, taking the indication information indicating that the multicast broadcast radio bearer needs to be reconfigured for the terminal device as an example, Figure 7 FIG. 2 shows another flow chart of the communication method provided in the embodiment of the present application. Figure 7 As shown, the communication method may include S701-S704.

[0255] S701. A first network device sends a radio resource control release message to a terminal device that has joined a multicast session. The radio resource control release message is used to instruct the terminal device to release to a non-connected state.

[0256] S701 may refer to the above-mentioned S501 and will not be described in detail herein.

[0257] S702: The first network device determines capability information of the second network device, where the capability information includes whether to support sending multicast services to terminal devices in a non-connected state.

[0258] When the second network device supports sending multicast services to terminal devices in a non-connected state, S703 is executed. When the second network device does not support sending multicast services to terminal devices in a non-connected state, subsequent steps are not executed.

[0259] S703: When the second network device supports the sending of multicast services by the terminal device in the non-connected state, the first network device sends indication information to the second network device, where the indication information is used to indicate that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0260] Correspondingly, the second network device receives the indication information from the first network device.

[0261] S704: The second network device sends the reconfigured multicast broadcast radio bearer to the terminal device.

[0262] S703-S704 may refer to the above-mentioned S502-S503, and will not be described in detail.

[0263] It can be understood that the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device. Figure 7 Similar, no further elaboration.

[0264] In this design, the first network device can send indication information only to the second network device that supports sending multicast services to terminal devices in a non-connected state, indicating whether the second network device needs to reconfigure the multicast broadcast radio bearer for the terminal device. For the second network device that does not support sending multicast services to terminal devices in a non-connected state, it is not necessary to send indication information, which can reduce signaling waste. In other words, in this design, the second network device can support sending multicast services to terminal devices in a non-connected state, such as the second network device can be an R18 base station.

[0265] In one possible design, the first network device may determine the capability information of the second network device when the Xn interface between the first network device and the second network device is established or modified.

[0266] Exemplarily, the Xn interface is an interface used to connect different network devices (such as gNB) in a 5G network, and is used to support transmission of the control plane and the user plane. The first network device can obtain the capability information of the second network device when establishing or modifying the Xn interface between the first network device and the second network device.

[0267] For example, when the Xn interface between the second network device and the first network device is established or modified, the second network device sends the capability information of the second network device to the first network device.

[0268] In this design, when the first network device establishes or modifies the Xn interface between it and the second network device, the capability information of the second network device is determined. The capability information of the second network device can be obtained by using the control plane message or user plane message of the Xn interface, thereby reducing signaling overhead.

[0269] In another possible design, the first network device may determine the capability information of the second network device based on a terminal device context migration request message from the second network device.

[0270] Exemplarily, the second network device may send a terminal device context migration request message to the first network device, and the terminal device context migration request message may include capability information of the second network device.

[0271] Among them, taking the UE that reselects to the cell corresponding to the second network device as the target UE as an example, the terminal device context migration request message can be the UE context migration request message of the target UE, and can also be the UE context migration request message of any other one or more UEs that have performed cell switching or reselection before the target UE reselects to the cell corresponding to the second network device. For example, when the first UE switches or reselects a cell between the first network device and the second network device, the second network device can send the capability information of the second network device to the first network device through the UE context migration request message of the first UE.

[0272] Alternatively, before the target UE reselects the cell corresponding to the second network device, when other UEs switch from the cell corresponding to the second network device or reselect to the cell corresponding to the first network device, the second network device may also send the capability information of the second network device to the first network device through the UE context migration response message of other UEs.

[0273] In this design, the first network device determines the capability information of the second network device based on the terminal device context migration request message from the second network device. The capability information of the second network device can be obtained through the terminal device context migration request message, and signaling overhead can also be reduced.

[0274] In yet another possible design, the first network device may determine capability information of the second network device based on operation, maintenance and management configuration information.

[0275] Exemplarily, the operation administration and maintenance (OAM) configuration information may include capability information of the second network device. The first network device may know whether the second network device supports sending multicast services to terminal devices in a non-connected state according to the OAM configuration information.

[0276] This design can use OAM configuration information to synchronize the capability information of the second network device to the first network device without using other messages, and can also reduce signaling overhead.

[0277] Optionally, the first network device may determine the capability information of the second network device according to one or more of the above implementation methods, or may obtain the capability information of the second network device through other messages. The present application does not limit the method for determining the capability information.

[0278] In one possible design, the first network device may use the terminal device context migration response message corresponding to the terminal device to send the above indication information to the second network device. For example, the step of the first network device sending the indication information to the second network device may include: the first network device sends the terminal device context migration response message corresponding to the terminal device to the second network device, and the terminal device context migration response message includes the indication information.

[0279] For example, Figure 8 FIG. 2 shows another flow chart of the communication method provided in the embodiment of the present application. Figure 8 As shown, the communication method may include S801-S806.

[0280] S801. The first network device sends an RRC release message to a terminal device that joins a multicast session. The RRC release message is used to instruct the terminal device to release to a non-connected state.

[0281] Accordingly, the terminal device receives an RRC release message.

[0282] Exemplarily, the first network device releases the UE to the non-connected state, which may include releasing the UE to the non-connected state to receive the multicast service, or releasing the UE to the non-connected state because there is no data or the multicast service session is deactivated. For details, reference may be made to the above-mentioned embodiment, which will not be repeated. When the UE is released to receive the multicast service in the non-connected state, the UE may continue to receive the multicast service in the non-connected state.

[0283] S802. The terminal device sends an RRC recovery request message to the second network device.

[0284] Correspondingly, the second network device receives the RRC recovery request message.

[0285] Exemplarily, the terminal device may initiate access in the cell corresponding to the second network device. The terminal device triggers RRC recovery and may send an RRC recovery request (RRCResumeRequest) message to the second network device. For example, a terminal device receiving a multicast service in a non-connected state may initiate access when the cell corresponding to the second network device does not have a corresponding multicast PTM configuration, or a terminal device in a non-connected state may initiate access in response to a paging message.

[0286] S803. The second network device sends a terminal device context migration request message to the first network device.

[0287] Correspondingly, the first network device receives the terminal device context migration request message.

[0288] Exemplarily, when the second network device and the first network device are different, after receiving the RRCResumeRequest message from the terminal device, the second network device may send a terminal device context migration request (RETRIEVE UE CONTEXT REQUEST) message to the first network device.

[0289] S804. The first network device sends a terminal device context migration response message to the second network device, where the terminal device context migration response message includes indication information.

[0290] Correspondingly, the second network device receives the terminal device context migration response message.

[0291] Exemplarily, the terminal device context migration response (RETRIEVE UE CONTEXT RESPONSE) message may include the context information of the terminal device. In this design, the terminal device context migration response message may also include the above-mentioned indication information, which may refer to the above-mentioned embodiment and is used to indicate whether the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0292] In some examples, for a UE receiving multicast, a RETRIEVE UE CONTEXT RESPONSE message may include a UE Context Information–Retrieve UE Context Response information element. The UE ContextInformation–Retrieve UE Context Response information element may include handover preparation information (HandoverPreparationInformation). The RRCRelease message or suspendconfig when releasing the UE may be introduced in the HandoverPreparationInformation as indication information to indicate to the second network device that the UE is released to the inactive receiving multicast service.

[0293] S805. The second network device sends an RRC recovery message to the terminal device.

[0294] Accordingly, the terminal device receives the RRC recovery message.

[0295] Exemplarily, after the terminal device completes access, the second network device may send an RRC resume (RRCResume) message to the terminal device, indicating that the terminal device has accessed. After the terminal device accesses, the second network device may execute S806 to reconfigure the MRB for the terminal device.

[0296] S806. The second network device sends the reconfigured multicast broadcast radio bearer to the terminal device.

[0297] Accordingly, the terminal device receives the reconfigured multicast broadcast radio bearer.

[0298] S806 can refer to the above S503, and will not be described in detail. It can be understood that when the indication information indicates that MRB reconfiguration is not required, there is no step described in S806.

[0299] In this design, the first network device sends indication information to the second network device through the terminal device context migration response message to indicate whether the terminal device needs to be MRB reconfigured. The indication information can be sent using existing messages, which can save signaling overhead and reduce implementation costs.

[0300] In another possible design, the first network device may also send indication information to at least one network device within the wireless coverage range of the first network device, where the at least one network device includes the second network device.

[0301] Exemplarily, the first network device may send indication information to all network devices within the wireless coverage area, and when the terminal device accesses one of the network devices, the network device is the second network device.

[0302] This design may not limit the timing of sending the indication information. When the first network device communicates with a network device within the wireless coverage area, the indication information may be sent to the network device through the Xn interface or other means. The sending of the indication information may be more flexible.

[0303] In another possible design, the first network device may send indication information to the second network device via a paging message. The second network device may receive a paging message sent from the first network device, where the paging message includes the indication information.

[0304] In this design, the indication information can also be sent through a paging message between network devices. For example, the indication information can be added in a position parallel to the paging identifier of the UE in the paging message. Sending the indication information through a paging message can also save signaling overhead, reduce implementation costs, and achieve more flexible sending of the indication information.

[0305] It should be noted that in some other possible designs, the indication information can also be sent through other messages, and this application does not limit the way in which the indication information is sent.

[0306] Optionally, in some other embodiments, the first network device may also send indication information to the second network device only when it is necessary to instruct the second network device to perform MRB reconfiguration on the terminal device, and the indication information may only indicate that the MRB reconfiguration on the terminal device is required. When the MRB reconfiguration on the terminal device is not required, the first network device may not send the indication information.

[0307] Optionally, in the above embodiment of the present application, the first network device may send the above indication information (refer to the above description) to the second network device according to the protocol, such as: 1bit field, TMGI list, suspendConfig information, RRCrelease message and other information, but for the first network device, it is not necessary to perceive the purpose of this information, that is, the first network device may not need to determine whether this information is used to indicate whether to perform MRB reconfiguration. The second network device that receives this information can still decide whether to perform MRB reconfiguration based on this information.

[0308] above Figures 5 to 8 The illustrated embodiment mainly introduces a scheme in which a first network device sends an indication message to a second network device to indicate whether a multicast broadcast radio bearer needs to be reconfigured for a terminal device. The embodiment of the present application also provides a communication method, in which a terminal device can indicate to a second network device whether a multicast broadcast radio bearer needs to be reconfigured for a terminal device. In the method, a terminal device that joins a multicast session can receive a radio resource control release message from a first network device, and the radio resource control release message is used to indicate that the terminal device is released to a non-connected state; the terminal device can send an indication message to a second network device, and the indication message is used to indicate whether a multicast broadcast radio bearer needs to be reconfigured for the terminal device. The second network device can receive an indication message from the terminal device; when the indication message indicates that a multicast broadcast radio bearer needs to be reconfigured for the terminal device, the second network device can send a reconfigured multicast broadcast radio bearer to the terminal device. When the indication message indicates that a multicast broadcast radio bearer does not need to be reconfigured for the terminal device, the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device.

[0309] For example, taking the example that the terminal device indicates to the second network device that a multicast broadcast radio bearer needs to be reconfigured for the terminal device, Fig. 9 FIG. 2 shows another flow chart of the communication method provided in the embodiment of the present application. Fig. 9 As shown, the communication method may include S901-S903.

[0310] S901. A first network device sends a radio resource control release message to a terminal device that has joined a multicast session. The radio resource control release message is used to instruct the terminal device to release to a non-connected state.

[0311] Correspondingly, the terminal device receives a radio resource control release message.

[0312] S901 may refer to the above-mentioned S501 and will not be described in detail herein.

[0313] S902. The terminal device sends indication information to the second network device, where the indication information is used to indicate that a multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0314] Correspondingly, the second network device receives the indication information.

[0315] Exemplarily, the terminal device may instruct the second network device to reconfigure the MRB for the terminal device by sending a message including the above instruction information to the second network device.

[0316] Exemplarily, in this embodiment, the terminal device may indicate to the second network device that the multicast broadcast radio bearer needs to be reconfigured for the terminal device. The implementation of the second network device reconfiguring the MRB for the terminal device may refer to the description in the above embodiment.

[0317] S903: The second network device sends a reconfigured multicast broadcast radio bearer to the terminal device.

[0318] Correspondingly, the terminal device receives the multicast broadcast radio bearer reconfigured for the terminal device from the second network device.

[0319] S903 may refer to the above-mentioned S503 and will not be described in detail herein.

[0320] above Fig. 9 The illustrated embodiment introduces a situation where the terminal device indicates to the second network device that a multicast broadcast radio bearer needs to be reconfigured for the terminal device. Fig.10 FIG. 2 shows another flow chart of the communication method provided in the embodiment of the present application. Fig.10 As shown, when the terminal device indicates to the second network device that there is no need to reconfigure the multicast broadcast radio bearer for the terminal device, the communication method may include S1001-S1003.

[0321] S1001. A first network device sends a radio resource control release message to a terminal device that has joined a multicast session. The radio resource control release message is used to instruct the terminal device to release to a non-connected state.

[0322] Correspondingly, the terminal device receives a radio resource control release message.

[0323] S1001 may refer to the above-mentioned S501 and will not be described in detail herein.

[0324] S1002. The terminal device sends indication information to the second network device, where the indication information is used to indicate that there is no need to reconfigure the multicast broadcast radio bearer for the terminal device.

[0325] Correspondingly, the second network device receives the indication information.

[0326] Exemplarily, the terminal device may send a message including the above indication information to the second network device, thereby indicating that the second network device does not need to reconfigure the MRB for the terminal device.

[0327] The second network device may not perform the operation of reconfiguring the MRB for the terminal device according to the instruction of the instruction information.

[0328] S1003: The second network device does not reconfigure the MRB for the terminal device.

[0329] It can be understood that, in actual implementation, there is no actual step in S1003, and the second network device does not need to perform the operation of reconfiguring the MRB on the terminal device. Fig.10 It is indicated by S1003 only for better explanation.

[0330] In this embodiment, the terminal device sends indication information to the second network device, indicating whether the second network device needs to reconfigure MRB for the terminal device joining the multicast session. This allows the second network device to clearly understand whether the terminal device needs to reconfigure MRB when the terminal device accesses, thereby providing the second network device with a decision-making basis for reconfiguring MRB.

[0331] based on Figures 9 and 10 The embodiment shown actually provides a communication method applied to a terminal device and a communication method applied to a second network device. In the communication method applied to the terminal device, the terminal device can receive a radio resource control release message from the first network device, and the radio resource control release message is used to instruct the terminal device to release to a non-connected state; the terminal device can send indication information to the second network device, and the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device. In the communication method applied to the second network device, the second network device can receive indication information from the terminal device; when the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device, the second network device can send a reconfigured multicast broadcast radio bearer to the terminal device; when the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device, the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device.

[0332] In one possible design, the above Fig. 9 and Fig.10 In the illustrated embodiment, the indication information may include the resident cell information of the terminal device, and the resident cell information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0333] In one implementation, the resident cell information may include information of all cells where the terminal device has resided. When at least one cell among all the cell information where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0334] Exemplarily, the indication information may include a list of all cells where the terminal device has resided. After receiving the indication information, the second network device may determine, based on the list of all cells where the terminal device has resided, whether there is at least one cell in all the cell information where the terminal device has resided that is not synchronized with the packet data convergence protocol (PDCP). When there is at least one cell that is not synchronized with the PDCP, it indicates that the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device, and the second network device may reconfigure the multicast broadcast radio bearer for the terminal device. Alternatively, when all cells are PDCP synchronized, it indicates that the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device, and the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device.

[0335] In another implementation, the resident cell information is used to indicate whether all the cells where the terminal device has resided are synchronized with the packet data convergence protocol. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0336] Different from the previous implementation, in this implementation, the resident cell information can directly indicate whether all the cells where the terminal device has resided are PDCP synchronized. For example, the resident cell information can indicate that there is at least one cell that is not PDCP synchronized, or indicate that all cells are PDCP synchronized. Similarly, when there is at least one cell that is not PDCP synchronized, the second network device can reconfigure the multicast broadcast radio bearer for the terminal device. Alternatively, when all cells are PDCP synchronized, the second network device may not reconfigure the multicast broadcast radio bearer for the terminal device.

[0337] In other words, all cells where the terminal device has resided are PDCP numbers generated based on the packet header information (MBSQFI SN) of the core network's data packet; if it has resided in a cell that is not PDCP synchronized, the PDCP variables (such as HFN) of the terminal device will be reset and will not be aligned with the PDCP variables of the synchronized cell. The terminal device can only report whether it has experienced an unsynchronized cell to indicate whether the second network device should reconfigure the multicast broadcast radio bearer for the terminal device. This method saves more signaling and leaves the complexity to the terminal device.

[0338] In another implementation, the resident cell information is used to indicate whether the last cell where the terminal device resided was packet data convergence protocol synchronization. When the last cell where the terminal device resided was not packet data convergence protocol synchronization, the resident cell information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0339] In this implementation, the terminal device may report to the second network device whether the last cell where the terminal device resided was PDCP synchronized through indication information, and the second network device may decide whether to perform MRB reconfiguration based on whether the last cell where the terminal device resided was PDCP synchronized. For example, when the last cell where the terminal device resided was not PDCP synchronized, the second network device performs MRB reconfiguration; or, when the last cell where the terminal device resided was PDCP synchronized, the second network device does not perform MRB reconfiguration.

[0340] In this design, the resident cell information of the terminal device can be used to indicate to the second network device whether reconfiguration of the multicast broadcast radio bearer is required. The terminal device does not need to make a decision on whether to reconfigure the MRB. The terminal device only provides the decision basis to the second network device.

[0341] In another possible design, the above Fig. 9 and Fig.10 In the illustrated embodiment, the indication information may also only indicate whether MRB reconfiguration is required.

[0342] For example, the terminal device can decide whether the second network device needs to reconfigure the multicast broadcast radio bearer for the terminal device based on the resident cell information. The decision-making method can refer to the decision-making method of the second network device described above, which will not be repeated. The terminal device can indicate to the second network device whether the multicast broadcast radio bearer needs to be reconfigured for the terminal device through indication information.

[0343] In this design, the logic for deciding whether the second network device needs to reconfigure the multicast broadcast radio bearer for the terminal device can be implemented on the terminal device side, and the second network device can execute the result based on the indication information reported by the terminal device, such as: reconfigure MRB or not reconfigure MRB.

[0344] Optionally, in this design, when the indication information includes the resident cell information of the terminal device described in any of the above implementations, reconfiguring MRB may refer to: the second network device instructs the UE to reconfigure the PDCP or to reconfigure part or all of the PDCP. For example, referring to the implementation of reconstructing MRB described in the aforementioned embodiment, the UE is instructed to reconstruct the PDCP entity and perform PDCP configuration, while the RLC configuration, MAC configuration and PHY configuration may or may not be reconfigured.

[0345] In some other possible designs, the indication information sent by the terminal device to the second network device can also be implemented by referring to the indication information sent by the first network device to the second network device in the aforementioned embodiment. For example, the indication information sent by the terminal device to the second network device may include one or more of the following: indication information indicating whether the terminal device is released to a non-connected state to receive multicast services, indication information indicating that the terminal device is released to a non-connected state to receive multicast service information, indication information including suspension configuration information, indication information including a radio resource control connection release message, indication information indicating that the terminal device is released to a non-connected state to receive MRB information used for multicast services, etc.

[0346] Exemplarily, in this design, the indication information may be a 1-bit indication field (refer to the foregoing description), TMGIlist, suspendConfig information, RRC release message, etc.

[0347] Optionally, in an embodiment of the present application, the terminal device may send the above-mentioned resident cell information (refer to the above description), TMGI list, suspendConfig information, RRC release message and other information to the second network device in accordance with the protocol, but the terminal device does not perceive the purpose of this information, that is, the terminal device may not need to determine whether this information is used to indicate whether to perform MRB reconfiguration. The second network device that receives this information can still decide whether to perform MRB reconfiguration based on this information.

[0348] In one possible design, the above Fig. 9 and Fig.10 In the illustrated embodiment, the indication information may be sent via a radio resource control recovery request message and / or a radio resource control recovery completion message. The step of the terminal device sending the indication information to the second network device may include: sending a radio resource control recovery request message to the second network device, the radio resource control recovery request message including the indication information; and / or sending a radio resource control recovery completion message to the second network device, the radio resource control recovery completion message including the indication information.

[0349] Accordingly, the second network device may receive a radio resource control recovery request message from the terminal device; and / or receive a radio resource control recovery completion message from the terminal device, wherein the radio resource control recovery completion message includes indication information.

[0350] For example, Fig.11 FIG. 2 shows another flow chart of the communication method provided in the embodiment of the present application. Fig.11 As shown, the communication method may include S1101-S1107.

[0351] S1101. The first network device sends an RRC release message to a terminal device that joins a multicast session. The RRC release message is used to instruct the terminal device to release to a non-connected state.

[0352] Accordingly, the terminal device receives an RRC release message.

[0353] S1101 may refer to the above-mentioned S801 and will not be described in detail herein.

[0354] S1102. The terminal device sends an RRC recovery request message to the second network device, where the RRC recovery request message includes indication information.

[0355] Correspondingly, the second network device receives the RRC recovery request message.

[0356] S1102 may refer to the above S802, the difference being that the RRC recovery request message includes indication information, and the indication information may indicate whether MRB reconfiguration is required.

[0357] S1103. The second network device sends a terminal device context migration request message to the first network device.

[0358] Correspondingly, the first network device receives the terminal device context migration request message.

[0359] S1103 may refer to the above-mentioned S803 and will not be described in detail herein.

[0360] S1104. The first network device sends a terminal device context migration response message to the second network device.

[0361] Correspondingly, the second network device receives the terminal device context migration response message.

[0362] S1105. The second network device sends an RRC recovery message to the terminal device.

[0363] Accordingly, the terminal device receives the RRC recovery message.

[0364] S1106. The terminal device sends an RRC recovery completion message to the second network device.

[0365] Correspondingly, the second network device receives an RRC resumption complete (RRCResumeComplete) message.

[0366] Exemplarily, after the terminal device accesses, the second network device may execute S1107 to reconfigure the MRB for the terminal device.

[0367] S1107. The second network device sends a reconfigured multicast broadcast radio bearer to the terminal device.

[0368] Accordingly, the terminal device receives the reconfigured multicast broadcast radio bearer.

[0369] S1107 can refer to the above S503, and will not be described in detail. It can be understood that when the indication information indicates that MRB reconfiguration is not required, there is no step described in S1107.

[0370] For example, Fig.12 FIG. 2 shows another flow chart of the communication method provided in the embodiment of the present application. Fig.12 As shown, the communication method may include S1201-S1207.

[0371] S1201. The first network device sends an RRC release message to a terminal device that joins a multicast session. The RRC release message is used to instruct the terminal device to release to a non-connected state.

[0372] Accordingly, the terminal device receives an RRC release message.

[0373] S1201 may refer to the above-mentioned S801 and will not be described in detail herein.

[0374] S1202. The terminal device sends an RRC recovery request message to the second network device.

[0375] Correspondingly, the second network device receives the RRC recovery request message.

[0376] S1202 may refer to the above-mentioned S802.

[0377] S1203. The second network device sends a terminal device context migration request message to the first network device.

[0378] Correspondingly, the first network device receives the terminal device context migration request message.

[0379] S1203 may refer to the above-mentioned S803 and will not be described in detail herein.

[0380] S1204. The first network device sends a terminal device context migration response message to the second network device.

[0381] Correspondingly, the second network device receives the terminal device context migration response message.

[0382] S1205. The second network device sends an RRC recovery message to the terminal device.

[0383] Accordingly, the terminal device receives the RRC recovery message.

[0384] S1206. The terminal device sends an RRC recovery completion message to the second network device, and the RRC recovery completion request message includes indication information.

[0385] Correspondingly, the second network device receives an RRC recovery complete (RRCResumeComplete) message. The indication information included in the RRC recovery complete message may indicate whether MRB reconfiguration is required.

[0386] Exemplarily, after the terminal device accesses, the second network device may execute S1207 to reconfigure the MRB for the terminal device.

[0387] S1207. The second network device sends a reconfigured multicast broadcast radio bearer to the terminal device.

[0388] Accordingly, the terminal device receives the reconfigured multicast broadcast radio bearer.

[0389] S1207 can refer to the above S503, and will not be described in detail. It can be understood that when the indication information indicates that MRB reconfiguration is not required, there is no step described in S1207.

[0390] In some other examples, the above-mentioned RRC recovery message and RRC recovery complete message may include indication information, which is not limited here.

[0391] In this design, the indication information can be sent via a wireless resource control recovery request message and / or a wireless resource control recovery completion message. The existing wireless resource control recovery request message and / or wireless resource control recovery completion message can be used to indicate to the second network device whether it is necessary to reconfigure the multicast broadcast wireless bearer for the terminal device, thereby saving signaling overhead and reducing implementation costs.

[0392] Optionally, the RRC recovery message may be called msg3, and the RRC recovery completion message may be called msg5. The message space of msg5 is larger, and when the indication information is sent in msg5, the message space can be better utilized.

[0393] The above embodiments respectively introduce two situations in which the first network device instructs the second network device whether to reconfigure the multicast broadcast radio bearer for the terminal device, and the terminal device instructs the second network device whether to reconfigure the multicast broadcast radio bearer for the terminal device. In some other embodiments of the present application, the indication information may not be sent to the second network device, and the second network device must reconfigure the MRB for the UE after the UE access is completed.

[0394] Exemplarily, an embodiment of the present application further provides a communication method that can be applied to a second network device. In the method, after receiving a radio resource control recovery completion message sent by a terminal device, the second network device can optionally perform an operation of reconfiguring the MRB of the terminal device, such as sending a reconfigured multicast broadcast radio bearer to the terminal device.

[0395] Optionally, in a possible design, the second network device may also obtain capability information of the terminal device, and the capability information of the terminal device includes: whether the terminal device supports receiving multicast services in a non-connected state. The terminal device may only perform the operation of reconfiguring the MRB for the terminal device for terminal devices that support receiving multicast services in a non-connected state. For example, when the terminal device supports receiving multicast services in a non-connected state, the second network device reconfigures the multicast broadcast radio bearer for the terminal device.

[0396] In this embodiment, the second network device may support sending multicast services to non-connected UEs, or may not support sending multicast services to non-connected UEs, and this application does not impose any restrictions on this.

[0397] It can be understood that, for any of the above embodiments, the second network device can clearly determine whether it is necessary to reconfigure the MRB for the UE, which can reduce MRB configuration anomalies on the UE side and reduce the occurrence of situations where the MBS multicast data cannot be received normally.

[0398] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of interaction between various network elements. It can be understood that each network element, such as the first network device, the second network device, the terminal device, etc., in order to realize the above functions, includes a hardware structure and / or software module corresponding to each function.

[0399] For example, with respect to the above scenario in which the first network device sends indication information to the second network device, the embodiment of the present application may further provide a communication device that can be applied to the above first network device. Fig.13 A schematic diagram of the structure of a communication device provided in an embodiment of the present application is shown.

[0400] like Fig.13 As shown, the communication device may include: a sending unit 1301.

[0401] Among them, the sending unit 1301 is used to send a wireless resource control release message to the terminal device that joins the multicast session, and the wireless resource control release message is used to instruct the terminal device to release to a non-connected state; the sending unit 1301 is also used to send an indication information to the second network device, and the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0402] In one possible design, when the terminal device is released to a non-connected state to receive multicast services, the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device; or, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device.

[0403] In one possible design, the indication information is specifically used to indicate whether the terminal device is released to a non-connected state to receive multicast services; or, the indication information is specifically used to indicate that the terminal device is released to a non-connected state to receive multicast service information; or, the indication information includes: suspension configuration information, and the suspension configuration information is used to indicate that the terminal device is released to a non-connected state to receive multicast service information.

[0404] In one possible design, the indication information includes a wireless resource control connection release message, and the wireless resource control connection release message includes suspension configuration information.

[0405] In one possible design, the apparatus further includes: a processing unit 1302, configured to determine capability information of a second network device, wherein the capability information includes whether to support sending multicast services to a terminal device in a non-connected state.

[0406] The sending unit 1301 is specifically configured to send indication information to the second network device when the second network device supports the terminal device in the non-connected state to send a multicast service.

[0407] In one possible design, the processing unit 1302 is specifically used to determine the capability information of the second network device when the Xn interface between the second network device is established or modified; or, to determine the capability information of the second network device based on a terminal device context migration request message from the second network device; or, to determine the capability information of the second network device based on operation, maintenance and management configuration information.

[0408] In one possible design, the sending unit 1301 is specifically used to send a terminal device context migration response message corresponding to the terminal device to the second network device, where the terminal device context migration response message includes indication information; or, to send indication information to at least one network device within the wireless coverage range of the first network device, where the at least one network device includes the second network device; or, to send indication information to the second network device via a paging message.

[0409] Optionally, the above Fig.13 The communication device shown may also include a receiving unit (not shown in the figure) for implementing a receiving function, such as receiving information from a second network device or a terminal device.

[0410] For another example: with respect to the above scenario in which the first network device sends indication information to the second network device, the embodiment of the present application may further provide a communication device that can be applied to the above second network device. Fig.14 Another structural schematic diagram of a communication device provided in an embodiment of the present application is shown.

[0411] like Fig.14As shown, the communication device may include: a receiving unit 1401 and a sending unit 1402.

[0412] Among them, the receiving unit 1401 is used to receive indication information from the first network device, the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device, and the terminal device is a terminal device joining the multicast session; the sending unit 1402 is used to send the reconfigured multicast broadcast radio bearer to the terminal device when the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

[0413] In one possible design, when the terminal device is released to a non-connected state to receive multicast services, the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device; or, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the indication information indicates that the multicast broadcast radio bearer does not need to be reconfigured for the terminal device.

[0414] In one possible design, the indication information is specifically used to indicate whether the terminal device is released to a non-connected state to receive multicast services; or, the indication information is specifically used to indicate that the terminal device is released to a non-connected state to receive multicast service information; or, the indication information includes: suspension configuration information, and the suspension configuration information is used to indicate that the terminal device is released to a non-connected state to receive multicast service information.

[0415] When the indication information indicates that the terminal device is released to a non-connected state to receive multicast services, the sending unit 1402 is specifically configured to send a multicast broadcast radio bearer reconfigured for all multicast services of the terminal device to the terminal device.

[0416] Alternatively, when the indication information indicates that the terminal device is released to a non-connected state to receive multicast service information, or the indication information includes suspension configuration information, the sending unit 1402 is specifically used to send a multicast broadcast radio bearer reconfigured for the terminal device to be released to a connected state to receive multicast service to the terminal device.

[0417] In one possible design, the indication information includes a wireless resource control connection release message, and the wireless resource control connection release message includes suspension configuration information.

[0418] In one possible design, the second network device supports sending multicast services to non-connected terminal devices.

[0419] In a possible design, the sending unit 1402 is further configured to send the capability information of the second network device to the first network device when the Xn interface with the first network device is established or modified; or, to send a terminal device context migration request message to the first network device, the terminal device context migration request message including the capability information of the second network device. Alternatively, the operation maintenance management configuration information includes the capability information of the second network device.

[0420] The capability information includes whether to support sending multicast services to terminal devices in a non-connected state.

[0421] In one possible design, the receiving unit 1401 is specifically used to receive a terminal device context migration response message corresponding to the terminal device sent from the first network device, and the terminal device context migration response message includes indication information; or, to receive a paging message sent from the first network device, and the paging message includes indication information.

[0422] For another example: With respect to the above scenario regarding the terminal device sending indication information to the second network device, an embodiment of the present application may also provide a communication device that can be applied to the above terminal device. Fig.15 Another structural schematic diagram of the communication device provided in an embodiment of the present application is shown.

[0423] like Fig.15 As shown, the communication device may include: a receiving unit 1501 and a sending unit 1502.

[0424] Among them, the receiving unit 1501 is used to receive a wireless resource control release message from the first network device, and the wireless resource control release message is used to instruct the terminal device to release to a non-connected state, and the terminal device is a terminal device that joins the multicast session; the sending unit 1502 is used to send an indication message to the second network device, and the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0425] In one possible design, the indication information includes resident cell information of the terminal device, and the resident cell information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0426] In one possible design, the resident cell information includes information of all cells where the terminal device has resided. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether all the cells where the terminal device has resided are synchronized with the packet data convergence protocol. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether the last cell where the terminal device has resided is synchronized with the packet data convergence protocol. When the last cell where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0427] In one possible design, the sending unit 1502 is specifically used to send a wireless resource control recovery request message to the second network device, the wireless resource control recovery request message includes indication information; and / or, to send a wireless resource control recovery completion message to the second network device, the wireless resource control recovery completion message includes indication information.

[0428] In one possible design, the receiving unit 1501 is further used to receive a multicast broadcast radio bearer reconfigured for the terminal device from the second network device.

[0429] For another example: With respect to the above scenario in which the terminal device sends indication information to the second network device, an embodiment of the present application may further provide a communication device that can be applied to the above second network device. Fig.16 Another structural schematic diagram of the communication device provided in an embodiment of the present application is shown.

[0430] like Fig.16 As shown, the communication device may include: a receiving unit 1601 and a sending unit 1602.

[0431] Among them, the receiving unit 1601 is used to receive indication information from a terminal device, the terminal device is a terminal device joining a multicast session, and the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; the sending unit 1602 is used to send the reconfigured multicast broadcast radio bearer to the terminal device when the indication information indicates that the multicast broadcast radio bearer for the terminal device needs to be reconfigured.

[0432] In one possible design, the indication information includes resident cell information of the terminal device, and the resident cell information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0433] In one possible design, the resident cell information includes information of all cells where the terminal device has resided. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether all the cells where the terminal device has resided are synchronized with the packet data convergence protocol. When at least one cell among all the cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device; or, the resident cell information is used to indicate whether the last cell where the terminal device has resided is synchronized with the packet data convergence protocol. When the last cell where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

[0434] In one possible design, the receiving unit 1601 is specifically used to receive a wireless resource control recovery request message from a terminal device, the wireless resource control recovery request message including indication information; and / or, to receive a wireless resource control recovery completion message from a terminal device, the wireless resource control recovery completion message including indication information.

[0435] Similarly, with respect to the above scenario in which the second network device must optionally perform MRB reconfiguration, an embodiment of the present application may also provide a communication device applied to the second network device, which may include a hardware structure and / or software module capable of implementing the functions of the second network device, such as a sending unit, a receiving unit, etc., which will not be repeated here.

[0436] It should be understood that the division of units in the above device is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or physically separated. Moreover, the units in the device can be all implemented in the form of software calling through processing elements; or all implemented in the form of hardware; or some units can be implemented in the form of software calling through processing elements, and some units can be implemented in the form of hardware.

[0437] For example, each unit can be a separately established processing element, or it can be integrated in a certain chip of the device. In addition, it can also be stored in a memory in the form of a program, and called and executed by a certain processing element of the device. In addition, all or part of these units can be integrated together, or they can be implemented independently. The processing element described here can also be called a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each unit above can be implemented by an integrated logic circuit of hardware in the processor element or in the form of software called by a processing element.

[0438] In one example, the unit in any of the above devices may be one or more integrated circuits configured to implement the above method, such as: one or more ASICs, or, one or more DSPs, or, one or more FPGAs, or a combination of at least two of these integrated circuit forms.

[0439] For another example, when the units in the device can be implemented in the form of a processing element scheduling program, the processing element can be a general-purpose processor, such as a CPU or other processor that can call a program. For another example, these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0440] The above unit for receiving is an interface circuit or input circuit of the device, which is used to receive signals from other devices. For example, when the device is implemented in the form of a chip, the receiving unit is an interface circuit or input circuit of the chip for receiving signals from other chips or devices. When the communication device includes a unit for sending, the unit for sending is an interface circuit or output circuit of the device, which is used to send signals to other devices. For example, when the device is implemented in the form of a chip, the sending unit is an interface circuit or output circuit of the chip for sending signals to other chips or devices.

[0441] For example, an embodiment of the present application may also provide a communication device, which may be applied to the first network device or the second network device, or a terminal device. The communication device may include: a processor and an interface circuit. The processor may include one or more.

[0442] When the communication device is applied to a first network device, the processor is used to communicate with other devices through an interface circuit and execute each step executed by the first network device in the above method.

[0443] When the communication device is applied to the second network equipment, the processor is used to communicate with other devices through the interface circuit and execute the various steps executed by the second network equipment in the above method.

[0444] When the communication device is applied to a terminal device, the processor is used to communicate with other devices through the interface circuit and execute the various steps executed by the terminal device in the above method.

[0445] In one implementation, the units for implementing the corresponding steps in the above method respectively by the first network device or the second network device, or the terminal device, can be implemented in the form of a processing element scheduling program. For example, the apparatus for the first network device or the second network device, or the terminal device may include a processing element and a storage element, and the processing element calls the program stored in the storage element to execute the method executed by the corresponding first network device or the second network device in the above method embodiment. The storage element can be a storage element on the same chip as the processing element, that is, an on-chip storage element.

[0446] In another implementation, the program for executing the method executed by the first network device or the second network device, or the terminal device in the above method can be in a storage element on a different chip from the processing element, that is, an off-chip storage element. In this case, the processing element calls or loads the program from the off-chip storage element to the on-chip storage element to call and execute the method executed by the first network device or the second network device, or the terminal device in the above method embodiment.

[0447] For example, an embodiment of the present application may also provide a communication device, which may include a processor for executing computer instructions stored in a memory, and when the computer instructions are executed, the device executes the method executed by the first network device or the second network device, or the terminal device. The memory may be located inside the communication device or outside the communication device. And the processor includes one or more.

[0448] In another implementation, the first network device or the second network device, or the terminal device implementing each step in the above method may be configured as one or more processing elements, which may be correspondingly arranged on the first network device or the second network device, or the terminal device, where the processing element may be an integrated circuit, for example, one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these integrated circuits. These integrated circuits may be integrated together to form a chip.

[0449] The units of the first network device or the second network device, or the terminal device that implement the various steps in the above method can be integrated together and implemented in the form of a SOC, and the SOC chip is used to implement the corresponding method. The chip can integrate at least one processing element and a storage element, and the corresponding method is implemented in the form of a program stored in the storage element by the processing element; or, the chip can integrate at least one integrated circuit to implement the corresponding method; or, the above implementation methods can be combined, and the functions of some units are implemented in the form of a processing element calling a program, and the functions of some units are implemented in the form of an integrated circuit.

[0450] The processing element here is the same as described above, and can be a general-purpose processor, such as a CPU, or can be one or more integrated circuits configured to implement the above method, such as: one or more ASICs, or, one or more microprocessors DSPs, or, one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms.

[0451] A storage element may be a memory or a collective term for multiple storage elements.

[0452] For example, an embodiment of the present application also provides a chip system, which can be applied to the above-mentioned first network device or second network device, or terminal device. The chip system includes one or more interface circuits and one or more processors; the interface circuit and the processor are interconnected by lines; the processor receives and executes computer instructions from the memory of the electronic device through the interface circuit to implement the method executed by the first network device or the second network device, or the terminal device in the above method embodiment. Among them, for the first network device or the second network device, or the terminal device, the electronic device can be the network device or the terminal device itself or a device in itself, or it can also be other devices that communicate with the network device or the terminal device.

[0453] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0454] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0455] The units described as separate components may or may not be physically separated, and the components shown as units may be one physical unit or multiple physical units, that is, they may be located in one place or distributed in multiple different places. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0456] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0457] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, such as a program. The software product is stored in a program product, such as a computer-readable storage medium, including a number of instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard drives, ROM, RAM, magnetic disks, or optical disks.

[0458] For example, an embodiment of the present application may also provide a computer-readable storage medium, including: computer software instructions; when the computer software instructions are executed in a first network device, or in a chip built into the first network device, the first network device may execute the method executed by the first network device as described in the aforementioned embodiment.

[0459] Alternatively, when the computer software instructions are executed in the second network device or in a chip built into the second network device, the second network device executes the method executed by the second network device as described in the foregoing embodiment.

[0460] Alternatively, when the computer software instructions are executed in the terminal device or in a chip built into the terminal device, the terminal device executes the method executed by the terminal device as described in the above embodiment.

[0461] Optionally, an embodiment of the present application also provides a communication device. Fig.17 FIG. 2 shows another structural diagram of a communication device provided in an embodiment of the present application. Fig.17 As shown, the communication device may include: a transceiver unit 1701 and a processing unit 1702. The transceiver unit 1701 may be used to send and receive information, or to communicate with other network elements. The processing unit 1702 may be used to process data. For example, the device may implement the method performed by the first network device or the second network device, or the terminal device, through the transceiver unit 1701 and the processing unit 1702.

[0462] Optionally, an embodiment of the present application further provides a computer program product, which, when executed, can implement the method executed by the first network device or the second network device, or the terminal device as described above.

[0463] Based on the above embodiments, an embodiment of the present application also provides a communication system, including: a first network device and a second network device; the first network device executes the method executed by the first network device as described in the aforementioned embodiment; the second network device executes the method executed by the second network device as described in the aforementioned embodiment.

[0464] An embodiment of the present application also provides a communication system, including: a terminal device and a second network device; the terminal device executes the method executed by the terminal device as described in the aforementioned embodiment; the second network device executes the method executed by the second network device as described in the aforementioned embodiment.

[0465] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A communication method, characterized in that: The method is applied to a first network device, and the method includes: Sending a radio resource control release message to a terminal device that joins the multicast session, wherein the radio resource control release message is used to instruct the terminal device to release to a non-connected state; Send indication information to the second network device, where the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

2. The method according to claim 1, characterized in that When the terminal device is released to a non-connected state to receive a multicast service, the indication information indicates that a multicast broadcast radio bearer needs to be reconfigured for the terminal device; Alternatively, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the indication information indicates that it is not necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

3. The method according to claim 1 or 2, characterized in that: The indication information is specifically used to indicate whether the terminal device is released to a non-connected state to receive a multicast service; Alternatively, the indication information is specifically used to indicate that the terminal device is released to receive multicast service information in a non-connected state; Alternatively, the indication information includes: suspension configuration information, and the suspension configuration information is used to indicate that the terminal device is released to receive multicast service information in a non-connected state.

4. The method according to claim 3, characterized in that The indication information includes the radio resource control connection release message, and the radio resource control connection release message includes the suspension configuration information.

5. The method according to any one of claims 1 to 4, characterized in that: The method further comprises: Determine capability information of the second network device, the capability information including whether to support sending multicast services for terminal devices in a non-connected state; The sending the indication information to the second network device includes: When the second network device supports sending multicast services to terminal devices in a non-connected state, the indication information is sent to the second network device.

6. The method according to claim 5, characterized in that The determining the capability information of the second network device includes: When establishing or modifying the Xn interface with the second network device, determining capability information of the second network device; Alternatively, determining the capability information of the second network device according to a terminal device context migration request message from the second network device; Alternatively, the capability information of the second network device is determined according to the operation, maintenance and management configuration information.

7. The method according to any one of claims 1 to 6, characterized in that: The sending the indication information to the second network device includes: Sending a terminal device context migration response message corresponding to the terminal device to the second network device, wherein the terminal device context migration response message includes the indication information; Alternatively, the indication information is sent to at least one network device within the wireless coverage range of the first network device, where the at least one network device includes the second network device; Alternatively, the indication information is sent to the second network device via a paging message.

8. A communication method, characterized in that: The method is applied to a second network device, and the method includes: Receiving indication information from a first network device, the indication information being used to indicate whether a multicast broadcast radio bearer needs to be reconfigured for a terminal device, the terminal device being a terminal device that joins a multicast session; When the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device, the reconfigured multicast broadcast radio bearer is sent to the terminal device.

9. The method according to claim 8, characterized in that When the terminal device is released to a non-connected state to receive a multicast service, the indication information indicates that a multicast broadcast radio bearer needs to be reconfigured for the terminal device; Alternatively, when the multicast session joined by the terminal device temporarily has no data or the multicast session is deactivated, the indication information indicates that it is not necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

10. The method according to claim 8 or 9, characterized in that: The indication information is specifically used to indicate whether the terminal device is released to a non-connected state to receive a multicast service; Alternatively, the indication information is specifically used to indicate that the terminal device is released to receive multicast service information in a non-connected state; Alternatively, the indication information includes: suspension configuration information, the suspension configuration information is used to indicate that the terminal device is released to receive multicast service information in a non-connected state; When the indication information indicates that the terminal device is released to a non-connected state to receive a multicast service, the sending of a reconfigured multicast broadcast radio bearer to the terminal device includes: Sending to the terminal device a multicast broadcast radio bearer reconfigured for all multicast services of the terminal device; Alternatively, when the indication information indicates that the terminal device is released to receive multicast service information in a non-connected state, or the indication information includes the suspension configuration information, sending a reconfigured multicast broadcast radio bearer to the terminal device includes: A multicast broadcast radio bearer reconfigured for the multicast service that the terminal device is released to receive in a connected state is sent to the terminal device.

11. The method according to claim 10, characterized in that The indication information includes a radio resource control connection release message, and the radio resource control connection release message includes the suspension configuration information.

12. The method according to any one of claims 8 to 11, characterized in that: The second network device supports sending multicast services to terminal devices in a non-connected state.

13. The method according to claim 12, characterized in that The method further comprises: When the Xn interface between the first network device and the first network device is established or modified, sending capability information of the second network device to the first network device; Alternatively, sending a terminal device context migration request message to the first network device, wherein the terminal device context migration request message includes capability information of the second network device; Alternatively, the operation, maintenance and management configuration information includes capability information of the second network device; The capability information includes whether to support sending multicast services for terminal devices in a non-connected state.

14. The method according to any one of claims 8 to 13, characterized in that: The receiving indication information from the first network device includes: receiving a terminal device context migration response message corresponding to the terminal device sent from the first network device, wherein the terminal device context migration response message includes the indication information; Alternatively, a paging message sent from the first network device is received, where the paging message includes the indication information.

15. A communication method, characterized in that: The method is applied to a terminal device, and the method comprises: Receiving a radio resource control release message from a first network device, wherein the radio resource control release message is used to instruct the terminal device to release to a non-connected state; Send indication information to the second network device, where the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

16. The method according to claim 15, characterized in that The indication information includes the resident cell information of the terminal device, and the resident cell information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

17. The method according to claim 16, characterized in that The resident cell information includes information of all cells where the terminal device has resided, and when at least one cell in all the cell information where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that a multicast broadcast radio bearer needs to be reconfigured for the terminal device; Alternatively, the resident cell information is used to indicate whether all cells where the terminal device has resided are synchronized with the packet data convergence protocol. When at least one cell among all cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that a multicast broadcast radio bearer needs to be reconfigured for the terminal device. Alternatively, the resident cell information is used to indicate whether the last cell where the terminal device resided was packet data convergence protocol synchronized. When the last cell where the terminal device resided was not packet data convergence protocol synchronized, the resident cell information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

18. The method according to any one of claims 15 to 17, characterized in that: The sending the indication information to the second network device includes: Sending a radio resource control restoration request message to the second network device, where the radio resource control restoration request message includes the indication information; And / or, sending a radio resource control recovery completion message to the second network device, wherein the radio resource control recovery completion message includes the indication information.

19. The method according to any one of claims 15 to 18, characterized in that: The method further comprises: Receive a multicast broadcast radio bearer reconfigured for the terminal device from the second network device.

20. A communication method, characterized in that: The method is applied to a second network device, and the method includes: Receiving indication information from a terminal device, where the terminal device is a terminal device that joins a multicast session, and the indication information is used to indicate whether a multicast broadcast radio bearer needs to be reconfigured for the terminal device; When the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device, the reconfigured multicast broadcast radio bearer is sent to the terminal device.

21. The method according to claim 20, characterized in that The indication information includes the resident cell information of the terminal device, and the resident cell information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

22. The method according to claim 21, characterized in that The resident cell information includes information of all cells where the terminal device has resided, and when at least one cell in all the cell information where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that a multicast broadcast radio bearer needs to be reconfigured for the terminal device; Alternatively, the resident cell information is used to indicate whether all cells where the terminal device has resided are synchronized with the packet data convergence protocol. When at least one cell among all cells where the terminal device has resided is not synchronized with the packet data convergence protocol, the resident cell information indicates that a multicast broadcast radio bearer needs to be reconfigured for the terminal device. Alternatively, the resident cell information is used to indicate whether the last cell where the terminal device resided was packet data convergence protocol synchronized. When the last cell where the terminal device resided was not packet data convergence protocol synchronized, the resident cell information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

23. The method according to any one of claims 20 to 22, characterized in that: The receiving instruction information from the terminal device includes: receiving a radio resource control restoration request message from the terminal device, wherein the radio resource control restoration request message includes the indication information; And / or, receiving a radio resource control recovery completion message from the terminal device, the radio resource control recovery completion message including the indication information.

24. A communication device, characterized in that: The device comprises: A sending unit, used to send a radio resource control release message to a terminal device that joins a multicast session, wherein the radio resource control release message is used to instruct the terminal device to release to a non-connected state; The sending unit is further used to send indication information to the second network device, where the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

25. A communication device, characterized in that: The device comprises: A receiving unit, configured to receive indication information from a first network device, wherein the indication information is used to indicate whether a multicast broadcast radio bearer needs to be reconfigured for a terminal device, wherein the terminal device is a terminal device that joins a multicast session; A sending unit is used to send a reconfigured multicast broadcast radio bearer to the terminal device when the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

26. A communication device, characterized in that: The device comprises: A receiving unit, configured to receive a radio resource control release message from a first network device, wherein the radio resource control release message is used to instruct the terminal device to release to a non-connected state; A sending unit is used to send indication information to the second network device, where the indication information is used to indicate whether it is necessary to reconfigure the multicast broadcast radio bearer for the terminal device.

27. A communication device, characterized in that: The device comprises: A receiving unit, configured to receive indication information from a terminal device, wherein the terminal device is a terminal device that joins a multicast session, and the indication information is used to indicate whether a multicast broadcast radio bearer needs to be reconfigured for the terminal device; A sending unit is used to send a reconfigured multicast broadcast radio bearer to the terminal device when the indication information indicates that the multicast broadcast radio bearer needs to be reconfigured for the terminal device.

28. A communication device, characterized in that: include: A processor, configured to execute computer instructions stored in a memory, wherein when the computer instructions are executed, the device executes the method according to any one of claims 1 to 7, or the method according to any one of claims 8 to 14.

29. A communication device, characterized in that: include: A processor, configured to execute computer instructions stored in a memory, wherein when the computer instructions are executed, the device executes a method as described in any one of claims 15 to 19, or a method as described in any one of claims 20 to 23.

30. A computer-readable storage medium, characterized in that: include: Computer software instructions; When the computer software instructions are executed in a network device or a chip built into the network device, the network device executes the method according to any one of claims 1 to 7, or the method according to any one of claims 8 to 14.

31. A computer-readable storage medium, characterized in that: include: Computer software instructions; When the computer software instructions are executed in a terminal device or a chip built into the terminal device, the terminal device executes the method according to any one of claims 15 to 19.

32. A computer-readable storage medium, characterized in that: include: Computer software instructions; When the computer software instructions are executed in a network device or a chip built into the network device, the network device executes the method according to any one of claims 20 to 23.

33. A communication system, characterized in that: include: a first network device and a second network device; The first network device executes the method according to any one of claims 1 to 7; The second network device executes the method according to any one of claims 8 to 14.

34. A communication system, characterized in that: include: The terminal device and the second network device; The terminal device executes the method according to any one of claims 15 to 19; The second network device executes the method according to any one of claims 20-23.

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