CN115551082A

CN115551082A - Communication method, device and system for multicast service

Info

Publication number: CN115551082A
Application number: CN202110745567.1A
Authority: CN
Inventors: 贾建鑫; 吴问付; 宗在峰
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2022-12-30
Also published as: WO2023273355A1

Abstract

The embodiment of the application discloses a communication method, a communication device and a communication system for multicast services, and solves the problem that under the scene that a terminal in an RRC inactive state moves from a first access network device to a second access network device, a source access network device cannot know whether the terminal leaves a multicast group corresponding to the multicast services, so that the number of terminals joining the multicast group cannot be updated in time. The method can comprise the following steps: when the terminal in the RRC inactive state is determined to be located outside the service area of the first access network equipment, the second access network equipment is informed of leaving the first area, the second access network equipment is triggered to inform the first access network equipment of updating second information of the context of the multicast service, or the UE context of the terminal is extracted from the first access network equipment, so that the first access network equipment is triggered to update the number of the terminals joining the multicast group. The method is applied to a scene that the terminal joining the multicast group moves between access network devices.

Description

Communication method, device and system for multicast service

Technical Field

The embodiment of the application relates to the technical field of communication, in particular to a communication method, device and system for multicast service.

Background

In a third generation partnership project (3 rd generation partnership project,3 gpp) network, there are multicast groups in which a plurality of terminals join a multicast service through access network equipment, and network side equipment sends data of the multicast service to the plurality of terminals through the same communication connection, that is, the data transmission requirement of point-to-multipoint, where multicast in this document may also be called multicast. Joining a multicast group herein may also be referred to as joining a multicast broadcast service session (MBS session), which may also be referred to as participating in the MBS session.

However, during the communication process, the terminal may be in a Connection Management (CM) -CONNECTED state (CM-CONNECTED) or a connection management-IDLE state (CM-IDLE) or an inactive state (which may be referred to as a RRC inactive state (CM-CONNECTED with RRC-inactive) including a CM CONNECTED state), when the terminal is in the inactive state, the RRC connection between the terminal and the access network device is in the inactive state, so that the access network device cannot know the current location of the terminal, and cannot determine whether the terminal has left the service area of the access network device, that is, leaves a receiving area corresponding to the multicast service data, cannot update the number of terminals joining the multicast group through the access network device in time, and cannot adjust resources for transmitting the multicast service data according to the number of terminals joining the multicast group through the access network device.

Disclosure of Invention

The embodiment of the application provides a communication method, a device and a system for multicast services, so as to solve the problem that access network equipment cannot timely update the number of terminals joining a multicast group due to the fact that the access network equipment cannot perceive that the terminals which are in an inactive state and join the multicast group leave the access network equipment.

In order to achieve the above purpose, the following technical solutions are adopted in the embodiments of the present application.

The first aspect provides a communication method of multicast service, which may be applied to a terminal in an RRC inactive state moving from a first access network device to a second access network device, and the terminal joining a multicast group corresponding to the multicast service through the first access network device; the method may include the terminal determining that the terminal is located outside a service area (which may be referred to as a first area) of a first access network device, the terminal sending first information to a second access network device, where the first information may be used to notify that the terminal moves out of the first area, triggering the second access network device to send second information, which updates a context of a multicast service, to the first access network device, so that the first access network device updates the number of terminals joining a multicast group in the context of the multicast service, or triggering the second access network device to send third information, which is used to extract a User Equipment (UE) context of the terminal from the first access network device, to the first access network device, so that the first access network device senses that a UE context of the terminal is extracted, and updating the number of terminals joining the multicast group based on the extracting operation.

Based on the method of the first aspect, after finding that the terminal moves out of the service area of the source access network device, the terminal timely notifies the target access network device (or referred to as a new access network device or a second access network device) that the terminal moves out of the service area of the source access network device, and triggers the target access network device to notify the source access network device to update the context of the multicast service or extract the UE context of the terminal from the source access network device according to the notification.

In a possible design, the first information includes identification information of a multicast service, the first information may further include a radio network temporary identifier of the terminal, the radio network temporary identifier includes an identifier of the first access network device, the radio network temporary identifier of the terminal is analyzed to obtain the identifier of the first access network device, and then the second information or the third information is sent to the first access network device according to the identifier of the first access network device, the first access network device may be obtained through the radio network temporary identifier of the terminal, and system design is simplified.

In one possible design, the first information is carried in a first RRC message for requesting recovery of an RRC connection of the terminal (resume), which may be an RRC recovery request (RRC resume request) message; alternatively, the first RRC message is an RRC message, and the first RRC message may be used to recover the RRC connection of the terminal, or the first RRC message is used to trigger the second access network device to send the second information or the third message to the first access network device.

Based on the possible design, the carrying mode of the first information can be flexibly and effectively designed, and meanwhile, under the condition that the first RRC message is an RRC recovery request message, the system design can be simplified and the signaling overhead can be saved.

In one possible design, the sending, by the terminal, the first information to the second access network device includes: and the terminal sends the first information to the second access network equipment through the signaling radio bearer. Optionally, the signaling radio bearer may be SRB0. Based on the possible design, when the terminal disconnects the RRC connection, the first information may be sent to the second access network device through the signaling radio bearer corresponding to the cell in which the terminal is located, that is, the first information is carried on the signaling radio bearer using the cell as the granularity, so that all terminals in the cell including the terminal can successfully receive the first information, and meanwhile, the system design is simplified.

In one possible design, the method further includes: the terminal receives information from a first area of a first access network device; the information of the first area may be used to indicate the first area, for example, the information of the first area may be one or more of the following: the identifier of the first access network device, the identifier of one or more cells (cell ID (s)) comprised by the first access network device, the List of cells (cell ID List) comprised by the first access network device, the first access network device supported/comprising/belonging to one or more tracking area identifiers (tracking area ID(s), TAI (s)), the first access network device supported/comprising/belonging to one or more tracking area lists (TA List), the Name of the first access network device (RAN Node Name), the one or more physical cell identifiers (PCI (s)) comprised by the first access network device, the physical cell identifier List (PCI List) comprised by the first access network device, the geographical information of the location where the first access network device is located (e.g. Global Positioning System (GPS) information, the one or more Central units (Central units) comprised by the first access network device, and/or the like) may be distributed by the first access network device based on the identifier (cell ID(s), the identifier of the first access network device (CU, CU) and/or the simplified cell identifier (CU).

In one possible design, the information in the first area is carried in a second RRC message used for suspending RRC connection of the terminal, for example, the second RRC message may be one or more of the following: an RRC connection suspend (RRC connection suspend) message, an RRC release message (release with suspend configuration) carrying a suspend configuration, or an RRC message for suspend/deactivate RRC connection, etc., without limitation. Based on the possible design, the information of the first area can be sent to the terminal in the RRC connection suspension procedure, which simplifies the system design and saves the signaling overhead.

In a second aspect, the present application provides a communication method for a multicast service, where the method may be applied to a scenario where a terminal moves from a first access network device to a second access network device and the terminal is in an RRC inactive state, and the method may include: the second access network equipment receives first information from the terminal, wherein the first information can be used for informing the terminal to move out of a first area (which can be referred to as a service area of the first access network equipment), and according to the first information, the second access network equipment sends second information for updating the context of the multicast service to the first access network equipment, so that the first access network equipment updates the context of the multicast service according to the second information; or sending third information for extracting the UE context of the terminal from the first access network equipment to the first access network equipment, so that the first access network equipment updates the number of the terminals joining the multicast group through the first access network equipment according to the third information.

Based on the method described in the second aspect, the second access network device may send the second information to the first access network device after receiving the first information sent by the terminal and knowing that the terminal leaves the first area, and trigger the first access network device to update the context of the multicast service, or send the third information to the first access network device, and extract the UE context of the terminal. Therefore, for the source access network device (for example, the first access network device), it can be known that the terminal leaves the multicast group corresponding to the multicast service managed by the source access network device, the source access network device can adjust the number of terminals joining the multicast group in time, and adjust the resource for transmitting the data of the multicast service in time according to the number of terminals joining the multicast group, thereby improving the resource utilization rate.

In one possible design, the first information includes identification information of the multicast service, and further includes a radio network temporary identifier of the terminal, where the radio network temporary identifier includes an identifier of the first access network device. The second access network device sending the second information or the third information to the first access network device according to the first information includes: and the second access network equipment sends the second information or the third information to the first access network equipment according to the identifier of the first access network equipment. Therefore, the first access network equipment can be obtained through the wireless network temporary identifier of the terminal, and the system design is simplified.

In a possible design, the second information includes identification information of the multicast service, so that the first access network device can update the context of the multicast service in time according to the identification information of the multicast service, for example, update the number of terminals joining the multicast group through the first access network device in the context of the multicast service, thereby simplifying system design.

In one possible design, the second information or the third information is carried in a request to extract a UE context; or the second information or the third information is carried in an Xn message. Based on the possible design, the second information or the third information is carried in the existing signaling message or other Xn messages on the Xn interface between the access network devices, so that the signaling overhead is saved, and the sending of the second information or the third information is effectively and flexibly realized.

In a third aspect, an embodiment of the present application further provides a communication method for a multicast service, where the method is applied to a terminal in an RRC inactive state moving from a first access network device to a second access network device, and the terminal joins a multicast group corresponding to the multicast service through the first access network device, and the method may include: and the first access network equipment receives second information for updating the context of the multicast service from the second access network equipment, and updates the context of the multicast service according to the second information.

Based on the method of the third aspect, the first access network device may update the context of the multicast service after receiving the indication of the second access network device, so that the number of the terminals that join the multicast group through the first access network device recorded by the first access network device is consistent with the actual number of the terminals that join the multicast group, which is convenient for the first access network device to adjust the resource for transmitting the data of the multicast service in time according to the updated number of the terminals that join the multicast group, and improves the resource utilization rate.

In a possible design, the second information includes identification information of the multicast service, that is, the second access network device indicates the identification information of the multicast service to the first access network device, so that the first access network device finds the context of the multicast service according to the identification information of the multicast service, and updates the context of the multicast service, thereby simplifying the system design.

In one possible design, the updating, by the first access network device, the context of the multicast service according to the second information includes: and the first access network device updates the number of the terminals joining the multicast group through the first access network device in the context of the multicast service according to the second information, for example, the number of the terminals is reduced by 1.

In a possible design, the second information further includes identification information of the terminal, and the updating, by the first access network device, the context of the multicast service according to the second information may further include: and the first access network equipment deletes the identification information of the terminal in the context of the multicast service according to the second information.

In one possible design, the second information includes a radio network temporary identifier of the terminal; the first access network equipment updates the context of the multicast service according to the second information, and the updating comprises the following steps: the first access network equipment acquires the identification information of the multicast service in the UE context of the terminal according to the wireless network temporary identification of the terminal, deletes the identification information of the terminal in the context of the multicast service according to the acquired identification information of the multicast service, or updates the number of the terminals which are added into the multicast group through the first access network equipment in the context of the multicast service.

Based on the possible design, the context of the multicast service can be acquired, and then the identification information of the terminals in the context of the multicast service is deleted or the number of the terminals joining the multicast group through the first access network device in the context of the multicast service is updated, so that the number of the terminals joining the multicast group is reduced by 1, the first access network device is convenient to adjust the resource for transmitting the data of the multicast service in time according to the number of the terminals joining the multicast group, and the resource utilization rate is improved.

In one possible design, the second information is carried in the request for extracting the UE context or the Xn message, so that signaling overhead is saved, and meanwhile, the second information is effectively and flexibly sent to the first access network device.

In a fourth aspect, an embodiment of the present application further provides a communication method for a multicast service, where the method may be applied to a terminal in an RRC inactive state moving from a first access network device to a second access network device, and the terminal joining a multicast group corresponding to the multicast service through the first access network device, where the method includes: and the first access network equipment receives third information from the second access network equipment, wherein the third information is used for extracting the UE context of the terminal from the first access network equipment, and the number of the terminals which join the multicast group through the first access network equipment is updated according to the third information.

Based on the method in the fourth aspect, in the process that the second access network device extracts the UE context of the terminal from the first access network device, if the terminal joins the multicast group through the first access network device, the number of terminals joining the multicast group through the first access network device is determined to be updated because the UE context of the terminal is extracted, for example, the number of terminals is reduced by 1, and the like, so that it is ensured that the number of terminals joining the multicast group through the first access network device, which is recorded by the first access network device, is consistent with the actual number of terminals joining the multicast group through the first access network device, which is convenient for the first access network device to adjust the resource for transmitting data of the multicast service in time according to the updated number of terminals joining the multicast group, and the resource utilization rate is improved.

In one possible design, the method further includes: and the first access network equipment deletes the identification information of the multicast service in the UE context of the terminal. Based on this possible design, the identification information of the multicast service may be deleted from the UE contexts, facilitating the determination of the number of terminals joining the multicast group by counting which UE contexts include the identification information of the multicast service.

In one possible design, the third information includes identification information of the multicast service. The second access network equipment indicates the identification information of the multicast service to the first access network equipment, so that the first access network equipment finds the context of the multicast service according to the identification information of the multicast service and updates the context of the multicast service, and system design is simplified.

In one possible design, the updating, by the first access network device, the number of terminals joining the multicast group through the first access network device according to the third information includes: the first access network device obtains the UE context of the terminal according to the third information, where the UE context of the terminal includes identification information of the multicast service, and updates the number of terminals joining the multicast group through the first access network device in the context of the multicast service according to the identification information of the multicast service, for example, reduces the number of terminals joining the multicast group by 1, so that the first access network device can adjust the resource for transmitting data of the multicast service in time according to the number of terminals joining the multicast group, and improve the resource utilization rate.

In one possible design, the method further includes: the first access network equipment sends information of a first area to the terminal, wherein the first area is a service area of the first access network equipment. Based on the possible design, the first access network equipment can indicate the service area of the first access network equipment to the terminal, and the system design is simplified.

In a fifth aspect, an embodiment of the present application further provides a communication method for a multicast service, where the method includes: the access network equipment distributes a wireless network temporary identifier of the multicast service according to the identifier information of the multicast service, obtains scrambled downlink control information according to the wireless network temporary identifier of the multicast service, and sends fourth information including the identifier information of the multicast service and the wireless network temporary identifier of the multicast service and the scrambled downlink control information, so that a terminal receiving/monitoring the fourth information obtains descrambled downlink control information according to the wireless network temporary identifier of the multicast service, and receives data of the multicast service according to the descrambled downlink control information.

Based on the method in the fifth aspect, the access network device sends the identification information of the multicast service and the radio network temporary identifier of the multicast service, so that when a terminal in an idle state or an inactive state exists in the multicast group, the terminal in the multicast group receives the identification information of the multicast service and the radio network temporary identifier of the multicast service, and in the case of being interested in the multicast service, obtains the descrambled downlink control information by using the radio network temporary identifier of the multicast service, receives the data of the multicast service scheduled by the descrambled downlink control information, and solves the problem that the terminal in the idle state or the inactive state cannot receive the data of the multicast service due to the fact that the RRC connection is disconnected with the access network device.

In one possible design, the fourth information is carried in a System Information Block (SIB); or, the fourth information is carried in a Master Information Block (MIB); alternatively, the fourth information is carried in a paging message. Based on this possible design, the access network device broadcasts/transmits the fourth information to the terminals in the cell efficiently and flexibly in various ways, so that even the terminal that disconnects the RRC connection can receive the fourth information.

In one possible design, the access network device sends the fourth information, including: the access network equipment sends the RRC message through a Signaling Radio Bearer (SRB). Based on the possible design, with the cell as the granularity, the access network device broadcasts/sends the fourth information to the terminals in the cell through the SRB corresponding to the cell, so that even the terminal disconnecting the RRC connection can receive the fourth information.

In a sixth aspect, an embodiment of the present application further provides a communication method for a multicast service, where the method includes: the terminal receives the fourth information which comprises the identification information of the multicast service and the radio network temporary identification of the multicast service and the scrambled downlink control information from the access network equipment, and receives the data of the multicast service from the access network equipment according to the fourth information and the scrambled downlink control information. The terminal may be in an idle state or an inactive state.

Based on the method described in the sixth aspect, for a terminal joining a multicast group, even if the terminal is in an idle state or an inactive state after the RRC connection is disconnected, the terminal may receive the identification information of the multicast service and the radio network temporary identification of the multicast service, which are sent by the access network device, and obtain the descrambled downlink control information by using the radio network temporary identification of the multicast service under the condition that the multicast service is interested, receive the data of the multicast service scheduled by the descrambled downlink control information, and solve the problem that the terminal in the idle state or the inactive state cannot receive the data of the multicast service due to the RRC connection being disconnected.

In a possible design, the terminal receives data of a multicast service from the access network device according to the fourth information and the scrambled downlink control information, and includes: when the terminal is interested in the multicast service, the terminal obtains the descrambled downlink control information according to the wireless network temporary identifier of the multicast service, and receives the data of the multicast service from the access network equipment according to the descrambled downlink control information. Based on the possible design, the wireless network of the multicast service is used for temporarily identifying the downlink control information of the data of the scrambled scheduling multicast service, and the scrambled downlink control information is scheduled only for the data of the multicast service, so that the transmission safety of the data of the multicast service is ensured, and the system design is simplified.

In one possible design, the fourth information is carried in an SIB; or, the fourth information is carried in the MIB; alternatively, the fourth information is carried in a paging message. Based on this possible design, the fourth information is efficiently and flexibly broadcasted/transmitted to the terminals in the cell in various ways, so that even a terminal that disconnects the RRC connection can receive the fourth information.

In one possible design, the terminal receives fourth information from the access network device, where the fourth information includes: and the terminal receives fourth information from the access network equipment through the SRB. Based on the possible design, the cell is taken as granularity, and the fourth information is received through a signaling radio bearer (such as SRB 0) corresponding to the cell, so that even a terminal disconnecting the RRC connection can receive the fourth information, and the system design is simplified.

In a seventh aspect, the present application provides a communication device, which may be a terminal or a chip or a system on a chip in a terminal, and may also be a functional module in a communication device for implementing the method according to the first aspect or any possible design of the first aspect, or a functional module in a communication device for implementing the method according to any possible design of the sixth aspect or the sixth aspect. The communication device may implement the functions performed by the communication device in each of the above aspects or possible designs, which may be implemented by hardware executing the corresponding software. The hardware or software comprises one or more modules corresponding to the functions. In one possible design, the communication device may include: the device comprises a processing unit, a receiving unit and a transmitting unit.

In a possible design, the terminal is in an inactive state, and the terminal joins a multicast group corresponding to the multicast service through the first access network device and moves from the first access network device to the second access network device. A sending unit, configured to send first information including identification information of a multicast service to a second access network device, where the first information is used to notify that a terminal moves out of a first area, and trigger the second access network device to send second information for updating a context of the multicast service to the first access network device, or send third information for extracting a UE context of the terminal from the first access network device to the first access network device.

In still another possible design, the receiving unit is configured to receive, from the access network device, fourth information that includes identification information of the multicast service and a radio network temporary identification of the multicast service, and scrambled downlink control information, and receive data of the multicast service from the access network device according to the fourth information and the scrambled downlink control information. In this possible design, the terminal may be in an idle state or an inactive state.

Specifically, the specific implementation manner of the communication device may refer to the behavior function of the terminal in the method according to any one of the possible designs of the first aspect or any one of the possible designs of the sixth aspect or the sixth aspect, and will not be described repeatedly.

In an eighth aspect, the present application provides a communication apparatus, which may be a second access network device or a chip or a system on a chip in the second access network device, and may also be a functional module in the communication apparatus for implementing the method in any possible design of the second aspect or the second aspect, where the communication apparatus may implement the functions performed by the communication apparatus in the above aspects or in each possible design, and the functions may be implemented by hardware executing corresponding software. The hardware or software comprises one or more modules corresponding to the functions. The communication apparatus may include: a receiving unit and a transmitting unit.

A receiving unit, configured to receive first information including identification information of a multicast service from a terminal, where the first information may be used to notify the terminal to move out of a first area (which may be referred to as a service area of a first access network device).

A sending unit, configured to send, according to the first information, second information used for updating a context of the multicast service to the first access network device, so that the first access network device updates the context of the multicast service according to the second information; or sending third information for extracting the UE context of the terminal from the first access network equipment to the first access network equipment, so that the first access network equipment updates the number of the terminals joining the multicast group through the first access network equipment according to the third information.

Specifically, the specific implementation manner of the communication apparatus may refer to the second aspect or a behavior function of the second access network device in any possible design of the second aspect, and details are not repeated.

In a ninth aspect, the present application provides a communication apparatus, which may be a first access network device or a chip or a system on chip in the first access network device, or may be a functional module in the communication apparatus for implementing the method according to any possible design of the third aspect or the third aspect, or a functional module in the communication apparatus for implementing the method according to any possible design of the fourth aspect or the fourth aspect. The communication device may implement the functions performed by the communication device in each of the above aspects or possible designs, which may be implemented by hardware executing the corresponding software. The hardware or software comprises one or more modules corresponding to the functions. The communication apparatus may include: a processing unit and a receiving unit.

In one possible design, the receiving unit is configured to receive second information for updating a context of the multicast service from a second access network device. And the processing unit is used for updating the context of the multicast service according to the second information.

In one possible design, the receiving unit is configured to receive third information for extracting a UE context of the terminal from the second access network device. And the processing unit is used for updating the number of the terminals which join the multicast group through the first access network equipment according to the third information.

Specifically, the specific implementation manner of the communication apparatus may refer to the behavior function of the first access network device in any possible design of the third aspect or the third aspect, or refer to the behavior function of the first access network device in any possible design of the fourth aspect or the fourth aspect, and details are not repeated here.

In a tenth aspect, the present application provides a communication apparatus, which may be an access network device or a chip or a system on a chip in an access network device, and may also be a functional module in the communication apparatus for implementing any possible design of the fifth aspect or the fifth aspect, where the communication apparatus may implement the functions performed by the communication apparatus in the above aspects or in each possible design, and the functions may be implemented by hardware to execute corresponding software. The hardware or software comprises one or more modules corresponding to the functions. The communication apparatus may include: a processing unit and a transmitting unit.

And the processing unit is used for distributing the wireless network temporary identifier of the multicast service according to the identifier information of the multicast service and acquiring the scrambled downlink control information according to the wireless network temporary identifier of the multicast service.

And the sending unit is used for sending fourth information comprising the identification information of the multicast service, the wireless network temporary identification of the multicast service and scrambled downlink control information, so that a terminal receiving/monitoring the fourth information obtains the descrambled downlink control information according to the wireless network temporary identification of the multicast service, and receives data of the multicast service according to the descrambled downlink control information.

Specifically, the specific implementation manner of the communication apparatus may refer to the behavior function of the access network device in any possible design of the fifth aspect or the fifth aspect, and will not be described repeatedly.

In an eleventh aspect, a communications apparatus is provided that includes one or more processors, one or more memories. The one or more memories coupled to the one or more processors for storing computer program code comprising computer instructions which, when executed by the one or more processors, cause the communication apparatus to perform method steps as performed by the terminal in the first aspect or any one of the possible designs of the first aspect; or to perform the method steps as performed by the second access network device in the second aspect or any one of the possible designs of the second aspect; or performing method steps as performed by the first access network device in any possible design of the third aspect or any possible design of the fourth aspect or the fourth aspect; or performing method steps as performed by the access network apparatus in the fifth aspect or any possible design of the fifth aspect; or to perform the method steps as performed by the terminal in any of the possible designs as described in the sixth aspect or the sixth aspect.

In a twelfth aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method steps as performed by the terminal in the first aspect or any one of the possible designs of the first aspect; or to perform the method steps as performed by the second access network device in the second aspect or any one of the possible designs of the second aspect; or performing method steps as performed by the first access network device in any possible design of the third aspect or any possible design of the fourth aspect or the fourth aspect; or to perform the method steps as performed by the access network device in the fifth aspect or any possible design of the fifth aspect; or to perform the method steps performed by the terminal in any of the possible designs as described in the sixth aspect or the sixth aspect.

In a thirteenth aspect, there is provided a computer-readable storage medium, which may be a readable non-volatile storage medium, having stored therein instructions, which, when run on a computer, cause the computer to perform the method steps performed by the terminal as in the first aspect or any one of the possible designs of the first aspect; or to perform the method steps as performed by the second access network device in the second aspect or any one of the possible designs of the second aspect; or performing method steps as performed by the first access network device in any possible design of the third aspect or any possible design of the fourth aspect or the fourth aspect; or to perform the method steps as performed by the access network device in the fifth aspect or any possible design of the fifth aspect; or to perform the method steps as performed by the terminal in any of the possible designs as described in the sixth aspect or the sixth aspect.

In a fourteenth aspect, there is also provided a communication system that may include a terminal as described in the first aspect or any one of the possible designs of the first aspect, a second access network device as described in the second aspect or any one of the possible designs of the second aspect, and a first access network device as described in the third aspect or any one of the possible designs of the third aspect or the fourth aspect or any one of the possible designs of the fourth aspect; or,

the communication system may comprise an access network apparatus as in the fifth aspect or any possible design of the fifth aspect and a terminal as in the sixth aspect or any possible design of the sixth aspect.

Drawings

Fig. 1 is a flowchart illustrating a terminal joining a multicast group corresponding to a multicast service according to an embodiment of the present application;

fig. 2 is a schematic diagram of a network architecture according to an embodiment of the present application;

fig. 3 is a schematic diagram of a 5G communication system according to an embodiment of the present application;

fig. 4 is a schematic diagram illustrating a communication device 400 according to an embodiment of the present disclosure;

fig. 5a is a flowchart of a communication method of a multicast service according to an embodiment of the present application;

fig. 5b is a flowchart of a communication method of a multicast service according to an embodiment of the present application;

fig. 6 is a flowchart of a communication method for multicast service according to an embodiment of the present application;

fig. 7 is a schematic diagram of sending fourth information according to an embodiment of the present application;

fig. 8 is a schematic diagram illustrating a communication device 80 according to an embodiment of the present disclosure;

fig. 9 is a schematic diagram illustrating a communication device 90 according to an embodiment of the present disclosure;

fig. 10 is a schematic diagram illustrating a communication device 100 according to an embodiment of the present disclosure;

fig. 11 is a schematic diagram illustrating a communication system according to an embodiment of the present application;

fig. 12 is a schematic composition diagram of a communication system according to an embodiment of the present application.

Detailed Description

In the communication system, if a certain terminal has a requirement for a multicast service, the terminal may establish Radio Resource Control (RRC) connection with an access network device, and in the RRC connected state, join a multicast group corresponding to the multicast service through the access network device, and receive data of the multicast service sent by the access network device to the multicast group. Which may provide network services for a terminal (e.g., data for a multicast service for a terminal) currently residing in a service area of the access network device.

It should be noted that, in the present application, joining a multicast group corresponding to a multicast service may be described alternatively as joining a multicast service, or joining a multicast group, or joining a Multicast Broadcast Service (MBS), or joining a multicast session corresponding to a multicast service (multicast session) or joining a multicast broadcast service session corresponding to a multicast service (MBS session), or joining a multicast group corresponding to a multicast session, and the like.

It should be noted that the multicast described in this application may refer to a communication mode that sends the same data to multiple terminals, and the name of the multicast is not limited in this application, and the multicast described in this application may be replaced by multicast or broadcast or multicast/broadcast (multicast/broadcast). The "multicast" in the present application is a broad concept, and may include multicast (multicast) or broadcast (broadcast), that is, the embodiments of the present application may be applied to both multicast service transmission and broadcast service transmission. The "multicast" referred to in this application may be replaced by "multicast or broadcast". In addition, the multicast session (multicast session) in the present application may be replaced by a multicast service session (multicast service session) or a multicast broadcast service session (MBS session), which is not limited.

Fig. 1 is a flowchart of a terminal joining a multicast group corresponding to a multicast service through an access network device, where the process may include:

s1, after establishing RRC connection between a terminal and access network equipment and being in a connection state, the terminal can send a join request (join request) to core network equipment through the access network equipment, wherein the join request can be used for requesting to join a multicast group corresponding to multicast service, and the join request can carry identification information of the multicast service.

S2, after the core network device receives a join request sent by a terminal and authorizes the terminal to join a multicast group corresponding to a multicast service, the core network device (e.g., a Session Management Function (SMF)) may send, to the access network device, N2 Session Management (SM) information (N2 SM Info) for the join request, where the N2 SM information may notify the access network device that the terminal may join the multicast group corresponding to the multicast service, and the N2 SM information may carry identification information of the multicast service and quality of service (QoS) information of the multicast service (e.g., quality of service identifiers (QoS identifiers, QFI) of the multicast service, quality of service policies (QoS profiles) of the multicast service, etc.), and may also carry relevant information of unicast QF mapped by a multicast quality of service flow (QoS flow, QF), such as unicast qi corresponding to the unicast QF, qoS Profile, etc., and may also carry identification information of the terminal, etc.

S3, after the access network device receives the N2 SM information, the access network device may store related information of the multicast service in a context of the multicast service, add 1 to the number of terminals of the multicast group in the context of the multicast service, add identification information of the terminals in the context of the multicast service, or store identification information of the multicast service in a UE context of the terminal (for example, a New Generation Application Protocol (NGAP) UE context of the terminal in the access network device), and configure an air interface radio bearer (such as a Data Radio Bearer (DRB) or a Multicast Radio Bearer (MRB)) for transmitting data of the multicast service according to the related information of the multicast service carried by the N2 SM message, and configure a radio network temporary identifier configured for the multicast service, such as a group-Radio Network Temporary Identifier (RNTI) corresponding to the multicast service. Optionally, the access network device may further store the identification information of the multicast service in a User Equipment (UE) context of the terminal, so as to indicate that the terminal joins the multicast group corresponding to the multicast service.

And S4, the access network equipment sends the information such as the radio network temporary identifier (such as the G-RNTI) of the multicast service to the terminals in the multicast group. Correspondingly, the terminal receives the information such as the wireless network temporary identifier of the multicast service from the access network equipment. Subsequently, the terminal may receive, according to the radio network temporary identifier of the multicast service, data of the multicast service that is transmitted by the access network device through the air interface radio bearer, for example, taking the radio network temporary identifier of the multicast service as G-RNTI, the access network device may scramble Downlink Control Information (DCI) with the G-RNTI to obtain scrambled DCI, where the DCI may be used to schedule the data of the multicast service, and after the access network device sends the scrambled DCI and successfully descrambles the scrambled DCI by using the G-RNTI at the terminal indicated by the DCI, the access network device receives the data of the multicast service on a Physical Downlink Shared Channel (PDSCH) indicated by the DCI.

In this embodiment of the present application, a multicast service context (multicast service context) may be described as a multicast broadcast service session context (MBS session context), a multicast broadcast context (MBS context), a multicast broadcast group context (MBS group context), a multicast broadcast service context (MBS service context), or the like instead of the multicast service context. After the terminal joins the multicast group corresponding to the multicast service through the access network device, the context of the multicast service can be stored in the access network device. The context of the multicast service corresponds to/is associated with the multicast service, and the context of the multicast service may include related information of the multicast service, for example, the context of the multicast service may include identification information of the multicast service, qoS information of the multicast service, information of a terminal that joins the multicast group through the access network device, and the like. The information of the terminal joining the multicast group through the access network device may include the number of terminals joining the multicast group through the access network device, and may further include identification information of the terminal joining the multicast group through the access network device. For example, UE1 to UE4 join a multicast group corresponding to a multicast service through base station 1, the context of the multicast service may include the number 4 of terminals joining the multicast group, or include the number 4 of terminals joining the multicast group and identification information { UE1, UE2, UE3, UE4} of the terminals.

In the embodiment of the present application, the identification information of the multicast service may be used to identify the multicast service. The identification information of the multicast service may be configured by an application layer of the terminal. The identification information of the multicast service may be equivalently replaced with identification information of a multicast group corresponding to the multicast service (e.g., a Temporary Multicast Group Identifier (TMGI)), or an Internet Protocol (IP) multicast address of an application server providing the multicast service, or a service identifier (service ID) of the multicast service, or packet filter (packet filter) information of the multicast service, or, service Data Flow (SDF) identification rules of the multicast service, or identification information of a multicast session for transmitting data of the multicast service, or a multicast/broadcast service identification (MBS ID), or a multicast/broadcast service session identification (MBS session ID), or a multicast/broadcast service identification, or a source specific IP multicast address (source specific IP address), or a Packet Detection Rule (PDR) of the multicast service, which is not limited herein. It should be understood that the PDR is a set of filters, each filter is a five-tuple, each filter contains a source address, a destination address, a source port number, a destination port number, a protocol number of the multicast traffic, and the PDR is used for filtering data of the multicast traffic.

In the embodiment of the application, the identification information of the terminal can be used for identifying the terminal. In one possible design, the identification information of the terminal may be referred to as identity information of the terminal, and the identification information of the terminal may be network-wide identification information of the terminal. Specifically, the identification information of the terminal may be an Internet Protocol (IP) address of the terminal, a Media Access Control (MAC) address of the terminal, an International Mobile Subscriber Identity (IMSI) of the terminal, a permanent identification information (SUPI) of the terminal, a 5G global unique temporary identifier (5G-guide) of the terminal, a hidden identifier (sui) of the terminal, a General Public Subscription Identifier (GPSI) of the terminal, a 5G short temporary subscriber identifier (5G-8978-PEI temporary identifier, a permanent identifier (TMSI) of the terminal, and the like. In yet another possible design, with the granularity of a cell or with the granularity of an access network device, the identification information of the terminal may be a radio network temporary identifier of the terminal, such as an RNTI of the terminal, which may be used to identify the terminal in a certain cell or a service area of the access network device, and the RNTI of the terminal corresponds to the cell/access network device. The RNTIs of the terminal when located in the service areas of different access network devices are different.

In a certain scenario, if RRC connection is established with an access network device, and a terminal in an RRC connection state has no data service requirement for a long time, the access network device may determine to suspend (suspend) the RRC connection of the terminal, send an RRC connection suspend (RRC connection suspend) message to the terminal, and after receiving the RRC connection suspend message, the terminal disconnects the RRC connection with the access network device and switches from a connection state to an inactive (inactive) state or an idle state. The terminal in the inactive state or the idle state cannot receive any data, such as data of a multicast service, through the access network device, and the access network device cannot acquire/monitor the location information of the terminal in the inactive state or the idle state. For example, taking the example that the UE1-UE4 join the multicast group corresponding to the multicast service through the base station 1, if the UE1 has no data service requirement for a long time, the base station 1 may suspend the RRC connection with the UE1, and at this time, the UE1 cannot receive the data of the multicast service sent by the base station 1.

In the embodiment of the present application, the connected state may be referred to as an RRC connected state. In a connected state, an RRC connection exists between the terminal and the access network device, a non-access stratum (NAS) signaling connection exists between the terminal and a mobility management network element (e.g., an access and mobility management function (AMF)), and an N2 interface connection of per UE granularity exists between the access network device and the mobility management network element. At this time, the access network device and the mobility management element both store the UE context of the terminal. The UE context of the terminal stored in the access network device is different from the UE context of the terminal stored in the mobility management element, for example, the UE context of the terminal stored in the access network device is related to data transmission of the terminal, and the access network device may know that the terminal is in the service area of the access network device or in the service area of the access network device according to the UE context of the terminal stored in the access network device. The UE context of the terminal stored by the mobility management element may include identification information of the terminal, location information of the terminal, a registration area of the terminal, a current Connection Management (CM) connection state of the terminal, and the like, and the mobility management element may know, according to the UE context of the terminal, which access network device may be used to locate or find the terminal.

In the embodiment of the present application, inactive (inactive) state: the access network device does not know whether the terminal resides in a specific cell within the service area of the access network device or is within the management range of the access network device, the mobile management network element knows which access network device the terminal is within, and the mobile management network element knows through which access network device the terminal can be located or found.

In the embodiment of the present application, the idle (idle) state may mean that there is no RRC connection between the terminal and the access network device. The idle state may be referred to as an RRC idle state. In an idle state, the UE context of the terminal is not stored in the access network device, an NAS signaling connection does not exist between the terminal and the mobility management element (e.g., AMF), an N2 interface connection of per UE does not exist between the access network device and the mobility management element, and the mobility management element stores the UE context of the terminal. The access network device does not know whether the terminal is within the service area of the access network device. The mobility management element does not know within the service area or within the management range of which access network device the terminal is in, and the access network device does not know through which access network device the terminal can be located or found.

In the embodiment of the present application, the UE context of the terminal stored on the access network device is related to data transmission of the terminal. For example, the UE context of the terminal stored on the access network device may include information of a Protocol Data Unit (PDU) session of the terminal, where the information of the PDU session includes unicast QoS parameters (e.g., qoS profile of unicast QF). Optionally, if the terminal joins the multicast group corresponding to the multicast service through the access network device, the UE context of the terminal may further include information related to the multicast service, for example, the UE context of the terminal may include identification information of the multicast service, qoS profile of multicast QF corresponding to the multicast service, mapping relationship between the multicast QF and unicast QF, and the like.

As can be seen from the above, when the terminal is in the inactive state or the idle state, the access network device providing the network service for the terminal does not know whether the terminal still resides in the service area of the access network device, and does not know which cell the terminal currently resides in. At this time, there may be an area where the terminal resides outside the service area of the access network device, and the terminal has left the multicast group corresponding to the multicast service managed by the access network device, but the access network device does not know the movement track of the terminal, and mistakenly thinks that the terminal is still in the service area of the access network device, so that the access network device does not update the number of terminals joining the multicast group, so that the number of terminals joining the multicast group through the access network device is not consistent with the actual number, and the access network device mistakenly thinks that the number of terminals in the multicast group is not changed and does not adjust the resource for transmitting data of the multicast service, which causes resource waste.

For example, taking the example that the UE1-UE4 join the multicast group corresponding to the multicast service through the base station 1, the UE1 and the UE2 have no data service requirement for a long time, suspend the RRC connection with the UE1 and the UE2, and are in an inactive state. At this time, it is assumed that UE1 and UE2 also leave the service area of base station 1 and no longer receive the network service provided by base station 1. However, for the base station 1, the location information of the UE in the inactive state cannot be obtained, and it is still considered that the number of the terminals joining the multicast group through the base station 1 is 4, so the resource for transmitting the data of the multicast service is not adjusted, but the number of the terminals actually joining the multicast group through the base station 1 is reduced to 2, and at this time, the base station 1 can save the resource by adjusting/reducing the resource for transmitting the data of the multicast service to the resource corresponding to the 2 UEs.

In order to solve the technical problem, an embodiment of the present application provides a communication method for a multicast service, where the method may be applied to a scenario in which a terminal in an inactive state moves from a first access network device to a second access network device, and the terminal joins in a multicast group corresponding to the multicast service through the first access network device. The method can comprise the following steps: when a terminal determines that the terminal is located outside a service area (which may be referred to as a first area) of first access network equipment, the terminal sends first information including identification information of a multicast service to second access network equipment, and triggers the second access network equipment to send second information for updating a context of the multicast service to the first access network equipment, so that the first access network equipment updates the context of the multicast service according to the received second information, for example, the number of terminals added to a multicast group in the context of the multicast service is reduced by 1, and the like; or triggering the second access network device to send third information for extracting the UE context of the terminal from the first access network device to the first access network device, so that the first access network device updates the number of the terminals joining the multicast group through the first access network device according to the third information. Therefore, the context of the multicast service or the number of the terminals joining the multicast group can be updated in time according to the movement condition of the terminal in the inactive state, and the problem of resource waste caused by the fact that the access network equipment mistakenly considers that the number of the terminals in the multicast group is not changed and does not adjust the resource for transmitting the data of the multicast service due to the fact that the number of the terminals joining the multicast group is inconsistent with the actual number due to the fact that the access network equipment does not update the number of the terminals joining the multicast group is avoided.

It should be understood that the first access network device described herein may be an access network device that provides network services for the terminal before the terminal moves (before the terminal camps on/moves to a cell corresponding to the second access network device), and the second access network device may be an access network device corresponding to a cell where the terminal currently locates/camps on. The first access network device may be referred to as a source access network device and the second access network device may be referred to as a target access network device.

It should be understood that the service area of the first access network device described herein may alternatively be described as a signal coverage area of the first access network device or a cell included in the first access network device, etc. A terminal or other device located in the service area of the first access network device may establish an RRC connection with the first access network device, through which network services provided by the first access network device are received, such as receiving data of multicast traffic from the first access network device.

The technical solutions in the embodiments of the present application are described below with reference to the drawings in the embodiments of the present application.

The communication method of the multicast service provided in the embodiment of the present application may be applied to the communication system shown in fig. 2, and as shown in fig. 2, the communication system may include a plurality of terminals, a first access network device, and a second access network device. Further, core network devices (such as a mobility management network element, a session management network element, and the like), a user plane network element, a Data Network (DN), and the like may also be included. A plurality of terminals in fig. 2 may join a multicast group corresponding to the multicast service through the first access network device. The network elements or devices involved in the architecture shown in fig. 2 are described below.

The terminal may be a device for implementing a wireless communication function, such as a terminal or a chip that can be used in the terminal. Among others, a terminal may be a UE, an access terminal, a terminal unit, a terminal station, a mobile station, a remote terminal, a mobile device, a wireless communication device, a terminal agent, or a terminal device, etc. in a 5G network or a future-evolution communication system. The access terminal may be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with wireless communication capability, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device or a wearable device, a Virtual Reality (VR) terminal device, an Augmented Reality (AR) terminal device, a wireless terminal in industrial control (industrial control), a wireless terminal in self driving (self driving), a wireless terminal in remote medical (remote medical), a wireless terminal in smart grid (smart grid), a wireless terminal in transport security (smart security), a wireless terminal in city (city), a wireless terminal in smart home (home), etc. The terminal may be mobile and may move from a first access network device to a second access network device. It should be understood that moving from the first access device to the second access network device in the embodiments of the present application may refer to moving from a service area of the first access network device to a service area of the second access network device, and so on.

The first access network device and the second access network device may be collectively referred to as an access network device, and are mainly used for implementing functions such as a physical layer function, resource scheduling and management, access control of a terminal, and mobility management. The access network device may be a device supporting wired access or a device supporting wireless access. Illustratively, the access network device may be AN Access Network (AN)/Radio Access Network (RAN), and may be composed of a plurality of 5G-AN/5G-RAN nodes. The 5G-AN/5G-RAN node may be: an Access Point (AP), a base station (nodeB, NB), an enhanced base station (eNB), a next generation base station (NR nodeB, gNB), a Transmission Reception Point (TRP), a Transmission Point (TP), or some other access node, etc.

The mobility management network element is mainly responsible for the operations of access authentication of the terminal, mobility management, signaling interaction between various functional network elements, and the like, such as: and managing the registration state of the user, the connection state of the user, the user registration and network access, the tracking area updating, the cell switching user authentication, the key safety and the like.

The session management network element is mainly used for realizing session management functions of a user plane transmission logic channel, such as establishment, release and change of PDU session.

The user plane network element may be used as an anchor point on a user plane transmission logic channel, and is configured to complete functions of routing and forwarding of user plane data, such as: a channel (i.e. a user plane transmission logic channel) is established between the network node and the terminal, and the channel forwards a data packet between the terminal and the DN, and is responsible for filtering data messages of the terminal, forwarding data, controlling rate and generating charging information.

DN, an operator network that may provide data transmission services to users, such as: an operator network or the like that provides an Internet Protocol (IP) multimedia service (IMS) to a user may be provided. The DN may have an AS deployed therein, and the application server may provide data transmission services to users. The DN may include an Application Server (AS).

It should be noted that fig. 2 is only an exemplary architecture diagram, and besides the functional units shown in fig. 2, the system may also include other functional network elements, such as: an operation and management (O & M) network element, and the like, which are not limited in this embodiment of the present application. In addition, the names of the devices in fig. 2 are not limited, and besides the names shown in fig. 2, the devices may also be named by other names, such as network element names with the same or similar functions instead of the names, without limitation.

The system shown in fig. 2 may be a third generation partnership project (3 rd generation partnership project,3 GPP) communication system, such as a 4th generation (4 g) communication system, a Long Term Evolution (LTE) system, a fifth generation (5g) communication system, a New Radio (NR) system, a next generation communication system, or a non-3 GPP communication system, which is not limited.

Taking the communication system shown in fig. 2 as the 5G communication system shown in fig. 3 as an example, as shown in fig. 3, a network element or entity corresponding to the access network device may be an NG-RAN, a network element or entity corresponding to the session management network element may be a Session Management Function (SMF) in the 5G communication system, a mobile management network element may correspond to an access and mobility management function (AMF), a network element or entity corresponding to the user plane network element may be a User Plane Function (UPF) in the 5G communication system, a network element or entity corresponding to the access network device may be a Radio Access Network (RAN) in the 5G communication system, and a network element or entity corresponding to the mobile management network element may be an access and mobility management function (AMF) in the 5G communication system. The network may further include a Policy Control Function (PCF), a network open function (NEF), an NRF, a UDR, a UDM, or the like.

Optionally, the first access network device, the terminal, and the like in this embodiment may also be referred to as a communication apparatus, which may be a general device or a special device, and this is not specifically limited in this embodiment of the present application.

Optionally, related functions of the first access network device, the terminal, and the like in this embodiment may be implemented by one device, may also be implemented by multiple devices together, and may also be implemented by one or more functional modules in one device, which is not specifically limited in this embodiment of the present application. It is understood that the above functions may be network elements in a hardware device, or may be software functions running on dedicated hardware, or a combination of hardware and software, or virtualized functions instantiated on a platform (e.g., a cloud platform).

In a specific implementation, each device shown in fig. 2, such as the terminal, the first access network device, the second access network device, and the like, may adopt the composition structure shown in fig. 4, or include the components shown in fig. 4. Fig. 4 is a schematic diagram illustrating a communication device 400 according to an embodiment of the present disclosure, where the communication device 400 may include a processor 401 and a memory 404. Further, the communication device 400 may further include a communication line 402 and a communication interface 403. The processor 401, the memory 404 and the communication interface 403 may be connected by a communication line 402.

The processor 401 may be a Central Processing Unit (CPU), a general purpose processor, a Network Processor (NP), a Digital Signal Processor (DSP), a microprocessor, a microcontroller, a Programmable Logic Device (PLD), or any combination thereof. The processor 401 may also be other devices with processing functions, such as a circuit, a device or a software module, without limitation.

A communication line 402 for transmitting information between the respective components included in the communication apparatus 400.

A communication interface 403 for communicating with other devices or other communication networks. The other communication network may be an ethernet, a Radio Access Network (RAN), a Wireless Local Area Network (WLAN), or the like. The communication interface 403 may be a module, a circuit, a transceiver, or any device capable of enabling communication.

A memory 404 for storing instructions. Wherein the instructions may be a computer program.

The memory 404 may be a read-only memory (ROM) or other types of static storage devices that can store static information and/or instructions, a Random Access Memory (RAM) or other types of dynamic storage devices that can store information and/or instructions, 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 compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc), magnetic disc storage media, other magnetic storage devices, and the like, without limitation.

It is to be noted that the memory 404 may exist independently from the processor 401 or may be integrated with the processor 401. The memory 404 may be used for storing instructions or program code or some data or the like. The memory 404 may be located within the communication device 400 or may be located outside the communication device 400, without limitation.

The processor 401 is configured to execute the instructions stored in the memory 404 to implement the communication method of the multicast service provided in the following embodiments of the present application. For example, when the communication apparatus 400 is a terminal or a chip or a system on a chip in a terminal, the processor 401 executes instructions stored in the memory 404 to implement the steps performed by the terminal in the embodiments described below in the present application. For another example, when the communication apparatus 400 is a first access network device or a chip or a system on chip in the first access network device, the processor 401 may execute instructions stored in the memory 404 to implement the steps performed by the first access network device in the following embodiments of the present application.

In one example, processor 401 may include one or more CPUs, such as CPU0 and CPU1 in fig. 4.

As an alternative implementation, the communication device 400 includes multiple processors, for example, the processor 407 may be included in addition to the processor 401 in fig. 4.

As an alternative implementation, the communication apparatus 400 further includes an output device 405 and an input device 406. Illustratively, the input device 406 is a keyboard, mouse, microphone, or joystick, among other devices, and the output device 405 is a display screen, speaker (spaker), among other devices.

It should be noted that the communication apparatus 400 may be a desktop computer, a portable computer, a network server, a mobile phone, a tablet computer, a wireless terminal, an embedded device, a chip system, or a device with a similar structure as that in fig. 4. Further, the constituent structure shown in fig. 4 does not constitute a limitation of the communication apparatus, and the communication apparatus may include more or less components than those shown in fig. 4, or combine some components, or a different arrangement of components, in addition to the components shown in fig. 4.

In the embodiment of the present application, the chip system may be composed of a chip, and may also include a chip and other discrete devices.

In addition, acts, terms, and the like referred to between the embodiments of the present application may be mutually referenced and are not limited. In the embodiment of the present application, the name of the message or the name of the parameter in the message that is interacted between the devices is only an example, and other names may also be used in specific implementation, which is not limited.

The following describes a communication method of a multicast service provided in an embodiment of the present application, by taking the architecture shown in fig. 2 as an example. Each network element in the following embodiments may have the components shown in fig. 4, which are not described in detail. It should be noted that, the actions, terms and the like related to the embodiments of the present application may be mutually referred to, and are not limited. In the embodiment of the present application, the name of the message exchanged between the devices or the name of the parameter in the message, etc. are only an example, and other names may also be used in the specific implementation, which is not limited. For example: the multicast described in the embodiments of the present application may be replaced by broadcast, multicast communication, multicast/broadcast, or multicast/broadcast. The determination in the embodiment of the present application may also be understood as creating (create) or generating (generate), the "including" in the embodiment of the present application may also be understood as "carrying" or "including" or the like, and the "disconnecting" in the embodiment of the present application may also be understood as "releasing" or "stopping" or "pausing" or the like. The embodiments of the present application are not particularly limited to these embodiments.

Fig. 5a is a communication method of a multicast service according to an embodiment of the present application, where the method may be applied to the following scenarios: under the condition that a terminal which joins in a multicast group through a certain access network device is in an inactive state, the terminal moves from the access network device to other access network devices. For example, in fig. 2, the terminal moves from the first access network device to the second access network device, the terminal joins the multicast group through the first access network device, and the terminal is in an inactive state. The method is described below by taking the system shown in fig. 2 as an example, and as shown in fig. 5a, the method may include:

s501: the terminal determines that the terminal is located outside the first area.

The terminal located outside the first area may be alternatively described as the terminal not being in the first area, or the terminal leaving a signal coverage area of the first access network device, or not being in a signal coverage area of the first access network device, and the like, without limitation.

The terminal may be any terminal that joins the multicast group corresponding to the multicast service through the first access network device in fig. 2, and the terminal may be in an inactive state. The first access network device may be an access network device corresponding to a cell in which the terminal resides, and the first access network device may establish an RRC connection with the terminal and provide a network service for the terminal through the RRC connection. In this embodiment, the first access network device may be referred to as a source access network device. After the terminal joins the multicast group through the first access network device, the first access network device may have the UE context of the terminal and the context of the multicast service. The information of the terminals joining the multicast group may be included in the context of the multicast service, for example, the number of the terminals joining the multicast group may be included, or the number of the terminals joining the multicast group and the identification information of the terminals joining the multicast group may be included. The identification information of the multicast service may be included in the UE context of the terminal. Specifically, the process that the terminal joins the multicast group corresponding to the multicast service through the first access network device may refer to the flow illustrated in fig. 1, and is not described again.

In the embodiment of the present application, the multicast service may refer to a service that is directed to multiple terminals, for example, the multicast service may be a television program, a file transfer service, intra-group voice or video communication, a broadcast service inside a fleet, and the like. A plurality of terminals to which the multicast service is directed may join a group, which may be referred to as a multicast group corresponding to the multicast service, and all terminals in the multicast group may be authorized or may receive data of the multicast service without authorization. That is, the multicast group corresponding to the multicast service may be a combination of a plurality of terminals receiving data of the multicast service, for example, the multicast group may be a fleet receiving commands issued by the same command center or a user group receiving the same television program.

In this embodiment of the application, the first area may be a service area of the first access network device, a signal coverage area of the first access network device, or one or more cells corresponding to the first access network device, and the first area may be referred to as a radio access network-based notification area (RNA) of the first access network device. The terminal in the first area may receive the network service provided by the first access network device, and perform service data transmission with the first access network device, for example, the terminal may receive data of a multicast service from the first access network device in the first area. In the embodiment of the present application, a signal coverage area of an access network device may be divided by using the access network device or a cell as a granularity to obtain a first area. For example, in the case of taking the access network device as the granularity, the first area may be the entire signal coverage area of the first access network device, and the default first area includes all cells under the signal coverage of the first access network device. In the case of using a cell as a granularity, the first area may include one or more cells that can provide a multicast service under the coverage of the first access network device, where the cell may be described as a sector instead, and at this time, one cell may correspond to one or more carriers, and the first access network device may transmit data of the multicast service to the terminal on the carrier corresponding to the cell. It should be understood that, in the embodiment of the present application, a cell capable of providing a multicast service may refer to a cell capable of performing data transmission of a multicast service on a carrier corresponding to the cell.

For example, assuming that the first access network device is a base station 1, and a cell 1, a cell 2, and a cell 3 exist under the base station 1, where the first access network device may transmit data of a multicast service on carriers corresponding to the cell 1 and the cell 2, in the case of taking the access network device as a granularity, the first area may be an entire signal coverage area of the base station 1, and the first area may include the cell 1, the cell 2, and the cell 3. In the case of cell granularity, the first region may include cell 1 as well as cell 2.

In this embodiment, the first area may be indicated/configured to the terminal by the first access network device, for example, the terminal may receive information of the first area from the first access network device, and the information of the first area may indicate the first area, for example, in a case that the access network device is used as a granularity, the information of the first area may be one or more of the following: an identity of the first access network device, an identity of one or more cells (cell ID (s)) comprised by the first access network device, a List of cells (cell ID List) comprised by the first access network device, first access network device supported/comprising/belonging to one or more tracking area identities (tracking area ID(s), TAI (s)), first access network device supported/comprising/belonging to one or more tracking area lists (TA List), a Name of the first access network device (RAN Node Name), one or more physical cell identities (PCI (s)) comprised by the first access network device, a physical cell identity List (PCI List) comprised by the first access network device, geographical information of a location where the first access network device is located (e.g. global positioning system (global positioning system, GPS) information, an identification of one or more Central units (CU (s)) and/or distributed units (DU (s)) comprised by the first access network device, an identification of a CU List and/or DU List comprised by the first access network device, etc. the identification of the access network device may be a global access network device identification (global gNB ID) of the first access network device or a radio access network Node Name (RAN Node Name) of the first access network device or a global radio access network Node identification (global RAN Node ID) of the first access network device, or a radio access network Node identification (RAN Node ID, etc. of the first access network device In this case, the information of the first area may include an identifier of one or more cells capable of providing the multicast service under the signal coverage of the first access network device, where the identifier of the cell may be a Physical Cell Identifier (PCI) or a global cell identity (CGI) of the cell, and the like.

In one example, the information of the first area is carried in a new signaling message, for example, may be carried in a new RRC message and sent to the terminal. In another example, in order to save signaling overhead, when the first access network device determines to suspend (suspend) the RRC connection of the terminal, the information of the first region may be carried in a second RRC message, which may be used to suspend the RRC connection of the terminal, so as to enable the terminal to be in an inactive state, for example, the second RRC message may be an RRC connection suspension (RRC connection suspend) message, or an RRC release with suspend configuration message, or an RRC message for suspending/deactivating the RRC connection, and the like, without limitation. Therefore, the first area can be indicated to the terminal in the process of suspending the RRC connection of the terminal, and the signaling overhead is saved. The second RRC message may also carry a radio network temporary identifier of the terminal (e.g., an inactive radio network temporary identifier (I-RNTI) of the terminal), a radio network temporary identifier of the multicast service, and other information, in addition to the information of the first area, without limitation.

In this embodiment of the present application, the radio network temporary identifier of the terminal may include a plurality of binary bits, the radio network temporary identifier of the terminal may be an identity identifier of the terminal when the terminal is in a signal coverage area (or cell) of the first access network device, the radio network temporary identifier of the terminal may be used to identify the terminal in the signal coverage area/cell of the first access network device, the radio network temporary identifier of the terminal is only applicable to the signal coverage area/cell of the access network device that allocates the radio network temporary identifier to the terminal, and is an identifier that takes a certain access network device/cell as a granularity, and is not an identifier that takes the entire communication network as a granularity. The radio network temporary identifier of the terminal is allocated by the access network device currently providing the network service for the terminal, for example, in the current situation, the radio network temporary identifier of the terminal is allocated by the first access network device. The radio network temporary identity of the terminal may include an identity of the first access network device, or may alternatively be described as the identity of the first access network device may be resolved/obtained from the radio network temporary identity of the terminal. Specifically, the first access network device may calculate the identifier of the cell where the terminal is located and the identifier information of the terminal according to a preset algorithm to obtain the wireless network temporary identifier of the terminal, or calculate the identifier of the first access network device and the identifier information of the terminal according to the preset algorithm to obtain the wireless network temporary identifier of the terminal. Specifically, the design format of the radio network temporary identifier of the terminal refers to the 3GPP communication protocol 38.300, which is not limited.

In the embodiment of the application, the radio network temporary identifier of the multicast service corresponds to the multicast service, the identifier information of the multicast service may be used to add downlink control information (such as DCI) for scheduling data of the multicast service, the downlink control information may be descrambled according to the identifier information of the multicast service, and the data of the multicast service is obtained according to the descrambled downlink control information, so as to ensure the security of data transmission of the multicast service. The radio network temporary identity of the multicast service may be a G-RNTI of the multicast service or a multicast radio network temporary identity (M-RNTI). The radio network temporary identifier of the multicast service may be obtained/allocated according to the identification information of the multicast service, for example, the radio network temporary identifier of the multicast service may be obtained by calculating the identification information of the multicast service according to a preset algorithm.

In this embodiment, the first access network device may determine to suspend the RRC connection of the terminal in any one of the following manners:

1. the first access network device receives an N2 suspend response (N2 suspend response) sent by the mobility management element (such as the AMF), where the N2 suspend response may be used to indicate that the N2 interface connection between the mobility management element and the first access network device for the terminal is to be stopped, and then the first access network device determines to suspend the RRC connection of the terminal.

2. The first access network device receives a path switch request response (path switch request response) sent by the mobility management network element, where the path switch request response may be used to instruct to switch a transmission path of the terminal from the first access network device to another access network device, and the first access network device determines to suspend RRC connection of the terminal.

3. If the first access network device determines that an inactivity timer corresponding to the terminal expires/times out, the first access network device determines that the terminal does not receive data for a long time, and determines to disconnect the RRC connection between the terminal and the first access network device.

Wherein the inactivity timer may be used to determine whether the terminal has not been transmitting traffic data for a long time. The inactive timer is correspondingly provided with a preset working time length. The inactivity timer may start to operate when the terminal stops service data transmission (e.g., receives/sends service data), and within the preset operation duration, if the terminal performs service data transmission, the terminal stops operating/does not operate any more, and at this time, the operation duration is less than the preset operation duration, otherwise, within the preset operation duration, if the terminal does not perform service data transmission, the inactivity timer operates/operates until the preset operation duration is ended. For example, when the terminal starts to stop service data transmission (e.g., receive/transmit service data), the inactivity timer is started/run, and if the inactivity timer runs for a preset working duration, it indicates that the terminal has not performed service data transmission for a longer time, and the RRC connection may be disconnected/suspended, so as to save power consumption of the terminal. The preset duration of the inactive timer can be set according to the requirement without limitation.

After the terminal receives the information of the first area from the first access network device, the first area can be determined according to the information of the first area. Subsequently, if there is a business transmission requirement in the mobile process for the terminal disconnecting the RRC connection, the terminal may periodically detect whether there is a suitable access network device around the terminal to provide network service, for example, the terminal may detect a Synchronization Signal (SS) sent by the access network device around the terminal (e.g., primary Synchronization Signal (PSS)/Secondary Synchronization Signal (SSs)), and the SS may include an identifier of a cell. The terminal selects an SS with higher signal quality, acquires the cell identifier according to the selected SS, determines the cell identified by the cell identifier, and provides network service for the cell by an access network device (such as a second access network device) corresponding to the cell. In this process, if the terminal finds that the cell identified by the cell identifier acquired by the terminal is not included in the first area, it is determined that the terminal leaves the first area, is outside the first area, and leaves the signal coverage area of the first access network device.

Specifically, when the information of the first area includes the identities of one or more cells, the terminal may check whether the calculated identities of the cells are included in the information of the first area, and if not, determine that the cell identified by the cell is not included in the first area. When the information of the first area includes the identifier of the first access network device, the terminal may calculate, according to the obtained identifier of the cell, an identifier of one access network device, and if the calculated identifier of the access network device is different from the identifier of the first access network device, it is determined that the cell identified by the cell is not included in the first area. The calculation relationship between the identifier of the cell and the identifier of the access network device corresponding to the cell may refer to the prior art, and is not described herein again.

S502: and the terminal sends the first information to the second access network equipment. Accordingly, the second access network device receives the first information.

The second access network device may be an access network device to which a cell where the terminal currently resides/is located belongs/corresponds. The second access network device is different from the first access network device, and the cell where the terminal currently resides/is located is outside the first area.

The first information may be used to notify the terminal to move out of the first area, and the first information may include identification information of the multicast service, and may also include other information, such as a radio network temporary identifier of the terminal. The description of the first area, the identification information of the multicast service, and the radio network temporary identifier of the terminal may refer to the above, which is not repeated herein.

For example, the terminal may carry the first information in a first RRC message, and send the first RRC message to the second access network device through a signaling radio bearer (SRB 0, for example). Or the first RRC message is sent to the second access network device through other signaling messages, without limitation.

In one possible design, the first RRC message may be used to request recovery of the RRC connection of the terminal. For example, the first RRC message may be an RRC recovery request (RRC resume request), that is, the first information is sent to the second access network device through an RRC recovery procedure, so as to reduce signaling overhead. Alternatively, in yet another possible design, the first RRC message may be a dedicated RRC message, which may be used to trigger the second access network device to send the second information for updating the context of the multicast service to the first access network device, or the RRC message may be used to trigger the second access network device to send the third information for extracting the UE context of the terminal from the first access network device to the first access network device.

S503: and the second access network equipment sends the second information to the first access network equipment according to the first information. Accordingly, the first access network device receives the second information, and performs S504a. Or the second access network device sends the third information to the first access network device according to the first information, and correspondingly, the first access network device receives the third information and executes S504b.

Wherein, the second information can be used for updating the context of the multicast service, and the third information can be used for extracting the UE context of the terminal from the first access network equipment. In a possible design, the second information and the third information may include identification information of the multicast service, and may further include other information, such as identification information of the terminal. In yet another possible design, where the first information includes a radio network temporary identity of the terminal, the second information, the third information may include a radio network temporary identity of the terminal (e.g., an I-RNTI of the terminal), and/or identity information of the terminal. The second information and the third information may be carried in a retrieve UE context request (retrieve UE context request), and the retrieve UE context request may be used to request to provide a UE context of the terminal. Alternatively, the second information and the third information may be carried in a newly added message, such as an Xn message. Alternatively, the second information and the third information may be carried in a UE context release (UE context request) request, and the UE context release request may be used to request release of a UE context of the terminal.

The description of the identifier information of the multicast service, the radio network temporary identifier of the terminal, and the identifier information of the terminal may refer to the above, which is not described herein again.

In an example, the first information includes identification information of a multicast service, the second access network device may determine, according to the identification information of the multicast service, to send the second information or the third information to the access network device corresponding to the terminal when joining the multicast group, and because it is unknown which access network device is specifically, the second access network device sends the second information or the third information to one or more access network devices around the second access network device and establishing an Xn connection with the second access network device, where the one or more access network devices include the first access network device.

In another example, the first information includes identification information of the multicast service and a radio network temporary identifier of the terminal, where the radio network temporary identifier of the terminal includes identification information of the first access network device, and the first access network device may obtain the identifier of the first access network device according to the radio network temporary identifier of the terminal, and send the second information or the third information to the first access network device according to the identifier of the first access network device.

S504a: and the first access network equipment updates the context of the multicast service according to the second information.

In one example, the second information includes identification information of the multicast service, and the updating, by the first access network device, the context of the multicast service according to the second information may include: the first access network device finds the context of the multicast service according to the identification information of the multicast service, and if the context of the multicast service includes the number of terminals joining the multicast group through the first access network device, the number of terminals joining the multicast group through the first access network device in the context of the multicast service is updated, for example, the number of terminals is reduced by 1. For example, suppose that the multicast service is MBS1, the first access network device is a base station 1, the second access network device is a base station 2, the terminals joining the multicast group corresponding to MBS1 through the base station 1 have UEs 1 to 4, the number of terminals joining the multicast group through the base station 1 included in the context of MBS1 is 4, at this time, if the bs1 receives the second information { MBS1} from the bs 2, the bs1 finds the context of the MBS1, and updates the number of terminals joining the multicast group through the bs1 in the context of the MBS1 to 3.

In another example, the second information includes identification information of the multicast service and identification information of the terminal, and the updating, by the first access network device, the context of the multicast service according to the second information may include: the first access network device finds the context of the multicast service according to the identification information of the multicast service, and if the context of the multicast service includes the number of terminals joining the multicast group through the first access network device, the number of terminals joining the multicast group through the first access network device in the context of the multicast service is updated, for example, the number of terminals is reduced by 1. And/or, if the context of the multicast service includes the identification information of the terminal joining the multicast group through the first access network device, the first access network device may delete the identification information of the terminal in the context of the multicast service according to the identification information of the terminal included in the second information.

For example, suppose the multicast service is MBS1, the first access network device is base station 1, the second access network device is base station 2, the terminals joining the multicast group corresponding to MBS1 through base station 1 have UE1-UE4, the number of terminals joining the multicast group through base station 1 included in the context of MBS1 is 4, and the identification information { UE1, UE2, UE3, UE4} of terminals joining the multicast group through base station 1 are included in the context of MBS1, at this time, if the base station 1 receives the second information { MBS1, UE1} from base station 2, then the base station 1 finds the context of MBS1, updates the number of terminals joining the multicast group through base station 1 in the context of MBS1 to 3, and deletes UE1 in the context of MBS1, so that the identification information of terminals joining the multicast group through base station 1 is updated to { UE2, UE3, UE4}.

In another example, the second information includes a radio network temporary identifier of the terminal and/or identification information of the terminal, and the updating, by the first access network device, the context of the multicast service according to the second information may include: the first access network device finds the UE context of the terminal according to the radio network temporary identifier of the terminal and/or the identifier information of the terminal, obtains the identifier information of the multicast service from the UE context, finds the context of the multicast service according to the identifier information of the multicast service, and updates the number of terminals that join the multicast group through the first access network device in the context of the multicast service, for example, reduces the number of terminals by 1. And/or deleting the identification information of the terminal in the context of the multicast service.

For example, suppose the multicast service is MBS1, the first access network device is base station 1, the second access network device is base station 2, the terminal that joins the multicast group corresponding to MBS1 through base station 1 has UE1-UE4, the number of terminals that join the multicast group through base station 1 included in the context of MBS1 is 4, and the identification information { UE1, UE2, UE3, UE4} of the terminal that joins the multicast group through base station 1, at this time, if the base station 1 receives the second information { UE1 and/or I-RNTI of UE1} from base station 2, then base station 1 finds the UE context of UE1 according to { UE1 and/or I-RNTI of UE1}, obtains MBS1 from the UE context of UE1, finds the context of MBS1 according to MBS1, updates the number of terminals that join the multicast group through base station 1 in the context of MBS1 to 3, and, in case that the second information includes UE1, deletes UE1 in the context of UE1, so that the identification information of the terminals that join the multicast group through base station 1 is updated to { UE2, UE3, UE4}.

S504b: and the first access network equipment updates the number of the terminals which join the multicast group through the first access network equipment according to the third information.

For example, the third information includes identification information of the terminal, and the updating, by the first access network device, the number of terminals joining the multicast group through the first access network device according to the third information may include: the first access network equipment finds the UE context of the terminal according to the identification information of the terminal, and extracts the UE context of the terminal to the second access network equipment.

In this scenario, after the first access network device extracts the UE context of the terminal to the second access network device, the first access network device may no longer have/exist/release the UE context of the terminal. For example, the third information is carried in the UE context release request, the first access network device releases the UE context of the terminal according to the UE context release request, and further may return a UE context release response to the second access network device, where the UE context release response may be used to indicate the UE context of the released terminal. Or after the first access network device extracts the UE context of the terminal to the second access network device, the UE context of the terminal still can be stored, but the UE context of the terminal does not have the identification information of the multicast service, that is, the identification information of the multicast service in the UE context of the terminal is deleted. For the first access network device, the number of UE contexts including the identification information of the multicast service stored in the first access network device is reduced by 1, so that the number of terminals joining the multicast group through the first access network device, which is determined according to the number of UE contexts of the identification information of the multicast service, is also reduced by 1, and the number of terminals joining the multicast group through the first access network device is updated.

For example, suppose that the UEs 1-UE5 join the multicast group through the base station 1, and the five UE contexts corresponding to the UEs 1-UE5 all have the identification information of the multicast service, at this time, if the UE1 leaves the service area of the base station 1 and reaches the service area of the base station 2, the UE1 no longer receives the multicast service provided by the base station 1. For the corresponding base station 1, after receiving the third information sent by the base station 2, the UE context of the UE1 may be sent to the base station 2, and there are no UE contexts of the UE1 in the base station 1, but four UE contexts corresponding to the UEs 2 to 5; or, the base station 1 reserves the UE context of the UE1, but deletes the identification information of the multicast service in the UE context of the UE 1. At this time, the number of the UE contexts including the identification information of the multicast service is 4 UE contexts corresponding to the UEs 2 to 5, and the number of the terminals joining the multicast group through the base station 1 determined according to the number of the UE contexts including the identification information of the multicast service also becomes 4.

Further, the third information may further include identification information of the multicast service, and the updating, by the first access network device according to the third information, the number of terminals joining the multicast group through the first access network device may further include: the first access network device finds the context of the multicast service according to the identification information of the multicast service, and updates the number of the terminals joining the multicast group through the first access network device in the context of the multicast service, for example, the number of the terminals is reduced by 1.

In this embodiment of the application, the first access network device may send a response message corresponding to the third information carried in the UE context of the terminal to the second access network device, for example, the response message carried in the response for extracting the UE context is sent to the second access network device.

Further, if the first information is carried in the RRC recovery request, and the terminal requests to establish an RRC connection with the second access network device, and the second access network device provides a network service for the terminal, and receives data of the multicast service through the second access network device, as shown in fig. 5b, the method may further include S505-S514:

s505: the second access network device and the terminal interact to complete RRC recovery, for example, the second access network device sends RRC recovery (RRC resume) to the terminal, and the terminal sends RRC recovery complete (RRC resume complete) to the access network device.

S506: the second access network device sends an N2 Path Switch Request (N2 Path Switch Request) to the mobility management element. Accordingly, the mobility management network element receives the N2 path switch request.

If the second access network device supports the multicast function, the N2 path switching request may include the QFI of the unicast QF successfully allocated with the radio bearer and/or the QFI of the unicast QF unsuccessfully allocated with the radio bearer in the unicast QF included in the PDU session of the terminal; the method can also comprise the step of successfully allocating the QFs of the multicast QFs of the radio bearers and/or the step of unsuccessfully allocating the QFs of the multicast QFs of the radio bearers (or failing to establish the radio bearers) in the multicast QFs of the multicast services. If the second access network device does not support the multicast function, the N2 path switching request may include the QFI of the unicast QF successfully allocated with the radio bearer and/or the QFI of the unicast QF unsuccessfully allocated with the radio bearer in the unicast QF included in the PDU session of the terminal, where the unicast QF includes the unicast QF corresponding to/mapped by the multicast QF. The N2 path switch request may be encapsulated in an N2 SM message.

Further, the N2 path switching request may further include tunnel endpoint identification information allocated by the second access network device. The N2 path switching request further includes location information (location information) of the terminal and the like.

S507: and the mobility management network element sends a PDU session context updating request to the session management network element according to the N2 path switching request. Accordingly, the session management network element receives a PDU session context update request.

The PDU session context update request (Nsmf _ PDU _ update smcontext request) may include information included in the N2 SM message in S506. Optionally, the location information of the terminal is also included.

S508: and the session management network element performs N4 session modification with the user plane network element according to the PDU session context updating request. Such as the session management network element sending an N4 session modification request to the user plane network element. Correspondingly, the user plane network element receives the N4 session modification request, returns an N4 session modification response to the session management network element, and the session management network element receives the N4 session modification response.

The N4 session update request (N4 session modification request) may carry the tunnel endpoint identifier information allocated by the second access network device. Optionally, if the tunnel endpoint identification information of the user plane network element is allocated by the session management network element, the N4 session update request may further include the tunnel endpoint identification information allocated to the user plane network element by the session management network element. And if the tunnel endpoint identification information of the user plane network element is distributed by the user plane network element, carrying the tunnel endpoint identification information of the user plane network element in the N4 session modification response.

In this embodiment, the tunnel endpoint identifier information of the second access network device and the tunnel endpoint identifier of the user plane network element are used to establish a PDU session between the second access network device and the user plane network element.

S509: and if the session management network element determines that the second access network device does not support the multicast function and a tunnel for transmitting data of the multicast service between the MB-UPF and the UPF is not established, the session management network element sends a message 01 to the MB-SMF. Accordingly, the MB-SMF receives message 01.

Wherein message 01 may be used to instruct the MB-SMF to inform the MB-UPF to establish a tunnel with the UPF. The message 01 may include tunnel endpoint identification information of the user plane network element, the tunnel endpoint identification information of the user plane network element may be used to establish a tunnel between the user plane network element and the MB-UPF for transmitting data of the multicast service, and the tunnel endpoint identification information of the user plane network element may be allocated by the session management network element.

S510: the MB-SMF sends message 02 to the MB-UPF according to message 01. Accordingly, the MB-UPF receives the message 02.

The message 02 may include tunnel endpoint identification information allocated by the MB-SMF for the MB-UPF and tunnel endpoint identification information of the user plane network element described in S509.

S511: the MB-SMF sends a message 03 to the session management network element. Accordingly, the session management network element receives the message 03.

Wherein the message 03 may include tunnel endpoint identification information of the MB-UPF.

Further, after receiving the message 03, the session management network element may perform N4 session modification with the user plane network element, for example, the session management network element sends an N4 session modification request carrying the tunnel endpoint identification information of MB-UPF to the user plane network element UPF, and correspondingly, the user plane network element receives the N4 session modification request and returns an N4 session modification response to the session management network element.

S512: and the session management network element sends a PDU session context update response to the mobility management network element. Accordingly, the mobility management element receives a PDU session context update response.

Wherein, the PDU session context update response (Nsmf _ PDU _ update _ smcontext response) may carry the tunnel endpoint identifier information allocated to the user plane network element by the session management network element.

S513: and the mobile management network element sends an N2 path switching request response to the second access network equipment.

The N2 path switch response (N2 path switch request ACK) may include tunnel endpoint identifier information and the like allocated to the user plane network element by the session management network element.

S514: the second access network device sends a UE context release (UE context release) request to the first access network device. Correspondingly, the first access network device receives the UE context release request, and releases the UE context of the terminal and other resources corresponding to the terminal, such as a PDU session of the terminal, according to the UE context release request.

Based on the method, when the terminal leaves the first area, the source access network device (such as the first access network device) is triggered to update the number of the terminals joining the multicast group through the first access network device in time, so that the number of the terminals joining the multicast group through the first access network device meets the actual situation of the terminals joining the multicast group through the first access network device at present, the first access network device is convenient to adjust the transmission resources of the multicast service in time according to the number of the terminals joining the multicast group through the first access network device, and the resource utilization rate is improved. Further, the terminal may also establish an RRC connection with the second access network device, where the second access network device interacts with the core network device, and establishes a resource for transmitting the data of the multicast service for the terminal again, so as to ensure that the terminal receives the data of the multicast service through the second access network device.

In a multicast communication scenario, for terminals in an inactive state or an idle state in a multicast group, even if the terminals have data requirements of a multicast service, the terminals cannot receive the data of the multicast service because the terminals disconnect the RRC connection with the access network device, and it is impossible to realize that all the terminals in the multicast group receive the data of the multicast service. For example, the multicast group includes a terminal 1, a terminal 2, and a terminal 3, where the terminal 2 and the terminal 3 are in idle states, and the terminal 1 is in an RRC connected state, only the terminal 1 may receive data of the multicast service sent by the access network device, and the terminal 2 and the terminal 3 cannot receive the data of the multicast service because they are in idle states.

In order to satisfy that all terminals in a multicast group receive data of a multicast service, an embodiment of the present application further provides a multicast communication method, where the method may include: the access network equipment distributes a wireless network temporary identifier of the multicast service according to the identifier information of the multicast service, acquires scrambled downlink control information according to the wireless network temporary identifier of the multicast service, and sends fourth information and the scrambled downlink control information, wherein the fourth information comprises the identifier information of the multicast service and the wireless network temporary identifier of the multicast service. Therefore, the terminal in the cell covered by the access network equipment can receive the fourth information, descramble the downlink control information according to the fourth information, and receive the data of the multicast service from the access network equipment according to the descrambled downlink control information. Specifically, this manner can be described with reference to the corresponding embodiment of fig. 6.

Fig. 6 is a communication method of a multicast service according to an embodiment of the present application, and as shown in fig. 6, the method may include:

s601: and the access network equipment allocates the wireless network temporary identifier of the multicast service according to the identifier information of the multicast service.

It should be understood that the terms and the like in the embodiments of the present application are only an example, and do not limit the aspects of the present application, for example, the "allocation" in the embodiments of the present application may be alternatively described as "configuration" and the like.

The access network device may be any access network device in fig. 2, for example, the access network device may be a first access network device or a second access network device, and the like, which is not limited. In a signal coverage area/service area of the access network device, there are a plurality of terminals joining the multicast group through the access network device, and among the plurality of terminals, there is a terminal in an idle state or an inactive state.

The radio network temporary identifier of the multicast service corresponds to the multicast service, and the radio network temporary identifier of the multicast service is used for scrambling Downlink Control Information (DCI) of data of the multicast service to be scheduled, so as to ensure the security of transmission of the data of the multicast service. The access network device may calculate the identification information of the multicast service by using a preset algorithm to obtain the temporary radio network identification of the multicast service. Specifically, the description of the identifier information of the multicast service and the radio network temporary identifier of the multicast service may refer to the above, which is not repeated herein.

S602: and the access network equipment acquires the scrambled downlink control information according to the wireless network temporary identifier of the multicast service.

The downlink control information may be used to schedule a Physical Downlink Shared Channel (PDSCH) carrying data of the multicast service, and the downlink control information may indicate a time-frequency resource location of the PDSCH carrying the data of the multicast service.

For example, the downlink control information may include a plurality of check bits, the length of the check bits is the same as the length of the radio network temporary identifier of the multicast service, and the access network device may perform scrambling processing on the check bits according to the radio network temporary identifier of the multicast service to obtain scrambled downlink control information. The scrambling processing method may be a preset calculation rule, and the method may refer to the prior art and is not described in detail.

S603: and the access network equipment sends the fourth information and the scrambled downlink control information. Correspondingly, the terminal receives the fourth information and the scrambled downlink control information from the access network equipment.

The fourth information may include identification information of the multicast service and a radio network temporary identification of the multicast service. The description of the identification information of the multicast service and the radio network temporary identifier of the multicast service may refer to the above, which is not repeated herein.

It should be understood that, in the embodiment of the present application, the order of transmitting the fourth information and the scrambled downlink control information is not limited, and the fourth information may be transmitted first, and then the scrambled downlink control information may be transmitted, or may be transmitted simultaneously, which is not limited. Further, the terminal may store the received fourth information, for example, the fourth information includes identification information of the multicast service and a radio network temporary identifier of the multicast service, which are correspondingly stored in the terminal. So that the subsequent terminal can descramble the downlink control information according to the wireless network temporary identifier of the multicast service and receive the data of the multicast service under the condition of being interested in the multicast service.

For example, the access network device may send the scrambled downlink control information on a resource (e.g., a control resource set (CORESET)) corresponding to the downlink control information. The resource corresponding to the downlink control information may be configured by the access network device and indicated to the terminal in the signal coverage area of the access network device, and the specific configuration manner may refer to the prior art and is not described in detail.

For example, the access network device may send the fourth information in a broadcast manner, so that a plurality of terminals in a signal coverage area of the access network device may receive the fourth information in a broadcast manner. Specifically, as shown in fig. 7, the process of transmitting the fourth information in a broadcast manner may include any one of the following three manners:

in the first mode, the fourth information is carried in a System Information Block (SIB) and is broadcast.

For example, as shown in fig. 7, the access network device may generate fourth information, and deliver the fourth information to a Radio Resource Control (RRC) layer of the access network device, the RRC of the access network device may carry the obtained fourth information in a system message block (SIB) to deliver the fourth information to a Radio Link Control (RLC) layer of the access network device, and the RLC layer of the access network device may transmit the fourth information SIB to a downlink shared channel (DL-SCH) of a Media Access Control (MAC) layer of the access network device through a Broadcast Control Channel (BCCH) in a logical channel, and transmit the fourth information SIB to a Physical Downlink Shared Channel (PDSCH) in a physical layer through the DL-SCH, and broadcast the fourth information via the PDSCH.

And in the second mode, the fourth information is carried in a Master Information Block (MIB) and is sent out.

For example, as shown in fig. 7, the RRC layer of the access network device may carry the acquired fourth information in the MIB, and send the MIB to the RLC layer of the access network device, where the RLC layer of the access network device sends the fourth information to a Broadcast Channel (BCH) in the MAC layer of the access network device through the BCCH, transmits the fourth information to a Physical Broadcast Channel (PBCH) through the BCH, and broadcasts the fourth information through the PBCH.

And thirdly, carrying the fourth information in a paging message and broadcasting the paging message.

For example, as shown in fig. 7, the RRC layer of the access network device may carry the acquired fourth information in a paging message, and send the paging message to a Paging Control Channel (PCCH) of an RLC layer of the access network device, send the paging message to a Paging Channel (PCH) of a MAC layer of the access network device through the PCCH, transmit the paging channel to the PDSCH through the PCH, and broadcast the paging channel through the PDSCH.

And fourthly, carrying the fourth information in the RRC message, and broadcasting the RRC message through the signaling radio bearer.

Wherein the signaling radio bearer may be SRB0. Taking SRB0 as an example, as shown in fig. 7, for example, the RRC layer of the access network device may carry the acquired fourth information in a downlink common control channel message (DL-CCCH-message), send the DL-CCCH-message carrying the fourth information to a Common Control Channel (CCCH) in the RLC layer of the access network device through SRB0, send the fourth information to the DL-SCH through the CCCH, transmit the fourth information to the PDSCH through the DL-SCH, and broadcast the fourth information through the PDSCH.

For example, in the case of the first, third, and fourth modes, the terminal may receive a PDSCH carrying fourth information, and acquire the fourth information from the PDSCH; or, in the case shown in the second mode, the terminal may receive the PBCH and acquire the fourth information from the PBCH.

S604: and the terminal receives the data of the multicast service from the access network equipment according to the fourth information and the scrambled downlink control information.

For example, the terminal may determine that the terminal is interested in the multicast service according to the identifier information of the multicast service carried by the fourth information, and descramble the received scrambled downlink control information by using the radio network temporary identifier of the multicast service carried by the fourth information, and if descrambling is successful, receive the PDSCH from the access network device at the time-frequency resource position indicated by the descrambled downlink control information, and obtain the data of the multicast service from the PDSCH.

It should be understood that, in the embodiment of the present application, the execution sequence of each step in the process is not limited, and as described above, the terminal may be determined to be interested in the multicast service first, and then the radio network temporary identifier of the multicast service is used to obtain the descrambled downlink control information, or the terminal may be determined to be interested in the multicast service first, and then the data of the multicast service is received according to the descrambled downlink control information, which is not limited.

The terminal is interested in the multicast service, and can replace the situation that the terminal has the requirement of receiving the data of the multicast service, or the terminal expects to receive the data of the multicast service, or the terminal has the requirement of the multicast service, and the like.

Based on the method shown in fig. 6, when there is a terminal in an idle state or an inactive state in a multicast group, the identifier information of the multicast service and the radio network temporary identifier of the multicast service are sent, so that the terminal in the multicast group can receive the identifier information of the multicast service and the radio network temporary identifier of the multicast service, and receive data of the multicast service by using the radio network temporary identifier of the multicast service under the condition that the multicast service is interested, thereby solving the problem that the terminal in the idle state or the inactive state cannot receive the data of the multicast service due to the RRC connection disconnection with an access network device.

The above-mentioned scheme provided by the embodiments of the present application is mainly introduced from the perspective of interaction between the nodes. It is understood that each node, for example, a terminal, an access network device, etc., contains corresponding hardware structures and/or software modules for performing each function in order to realize the functions. Those of skill in the art will readily appreciate that the present application is capable of hardware or a combination of hardware and computer software implementing the various illustrative algorithm steps described in connection with the embodiments disclosed herein. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiment of the present application, the terminal, the access network device, and the like may be divided into functional modules according to the above method examples, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. It should be noted that, in the embodiment of the present application, the division of the module is schematic, and is only one logic function division, and there may be another division manner in actual implementation.

Fig. 8 shows a block diagram of a communication device 80, and the communication device 80 may be a terminal, a chip in the terminal, a system on chip, or other devices capable of implementing the functions of the terminal in the above method. The communication means 80 may be adapted to perform the functions of the terminal as referred to in the above-described method embodiments. As one implementation, the communication device 80 shown in fig. 8 includes: a processing unit 801, a receiving unit 802, and a transmitting unit 803.

In one possible design, the processing unit 801 is configured to determine that the terminal is located outside a service area of the first access network device. For example, the processing unit 801 may be configured to support the communication device 80 to perform S501.

A sending unit 803, configured to send, to the second access network device, first information for notifying that the terminal moves out of the first area. For example, the sending unit 803 may support the communication device 80 to perform S502.

In a possible design, the receiving unit 802 is configured to receive, from an access network device, fourth information including identification information of a multicast service and a radio network temporary identification of the multicast service, and scrambled downlink control information, and receive, according to the fourth information and the scrambled downlink control information, data of the multicast service from the access network device. For example, the receiving unit 802 may support the terminal to perform S603 and S604.

Specifically, the specific implementation manner of the communication device may refer to the behavior function of the terminal in the method according to any one of the possible designs of the first aspect or any one of the possible designs of the fifth aspect or the fifth aspect, and will not be described repeatedly.

Specifically, all relevant contents of each step related to the method embodiments shown in fig. 5a to fig. 6 may be referred to the functional description of the corresponding functional module, and are not described herein again. The communication device 80 is used for performing the functions of the terminal in the communication method of the multicast service shown in the method shown in fig. 5 a-6, so that the same effects as those of the communication method of the multicast service described above can be achieved.

As still another implementation, the communication device 80 shown in fig. 8 includes: a processing module and a communication module. The processing module is used for controlling and managing the actions of the communication device 80, and for example, the processing module may integrate the functions of the processing unit 801. The communication module may integrate the functions of the transmitting unit 803 and the receiving unit 802, perform S502, S603, S604 and communicate with other network entities, for example, with the functional modules or network entities shown in fig. 3. Further, the communication device 80 may also include a storage module for storing instructions and/or data. The instructions, when executed by the processing module, cause the processing module to implement the above-described method at the terminal side.

The processing module may be a processor, a controller, a module, or a circuit. Which may implement or perform the various illustrative logical blocks described in connection with the disclosure of the embodiments of the application. The communication module may be a transceiver circuit, a pin, an interface circuit, a bus interface, a communication interface, or the like. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication device 80 according to the embodiment of the present application may be the communication device 400 shown in fig. 4.

Fig. 9 shows a block diagram of a communication device 90, where the communication device 90 may be a second access network device, a chip in the second access network device, a system on chip, or other device capable of implementing the function of the second access network device in the above method. The communication means 90 may be adapted to perform the functions of the second access network device as referred to in the above-described method embodiments. As one implementation, the communication device 90 shown in fig. 9 includes: receiving section 901 and transmitting section 902.

A receiving unit 901, configured to receive first information from the terminal, where the first information is used to notify the terminal to move out of the first area. For example, the receiving unit 901 may support the communication device 90 to perform S502.

A sending unit 902, configured to send, according to the first information, second information or third information to the first access network device, where the second information is used to notify that the context of the multicast service is updated, and the third information is used to extract a UE context of the terminal from the first access network device. For example, the sending unit 902 may support the communication device 90 to perform S503.

Specifically, all relevant contents of each step related to the method embodiment shown in fig. 5a may be referred to the functional description of the corresponding functional module, and are not described herein again. The communication device 90 is used to perform the function of the second access network equipment in the communication method of the multicast service shown in the method shown in fig. 5a, so that the same effect as the communication method of the multicast service described above can be achieved.

As yet another implementation, the communication device 90 shown in fig. 9 includes: a processing module and a communication module. The processing module is used for controlling and managing the actions of the communication device 90. The communication module may integrate the functions of the receiving unit 901 and the sending unit 902, such as performing S502, S503, etc., and communication with other network entities, such as communication with the functional modules or network entities shown in fig. 4 or fig. 5 a. Further, the communication device 90 may also include a storage module for storing instructions and/or data. The instructions, when executed by the processing module, cause the processing module to implement a method on the second access network device side.

The processing module may be a processor, a controller, a module, or a circuit. Which may implement or perform the various illustrative logical blocks described in connection with the disclosure of the embodiments of the application. The communication module may be a transceiver circuit, a pin, an interface circuit, a bus interface, a communication interface, or the like. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication device 90 according to the embodiment of the present application may be the communication device 400 shown in fig. 4.

Fig. 10 shows a block diagram of a communication apparatus 100, where the communication apparatus 100 may be a first access network device, a chip in the first access network device, a system on chip, or other apparatuses capable of implementing the function of the first access network device in the above method. Or may be an access network device, a chip in the access network device, a system on chip, or other devices capable of implementing the functions of the access network device in the above method. The communication apparatus 100 may be used to perform the functions of the first access network device/access network device referred to in the above-described method embodiments. As one implementation manner, the communication apparatus 100 shown in fig. 10 includes: processing section 1001, receiving section 1002, and transmitting section 1003.

In a possible design, the receiving unit 1002 is configured to receive second information for updating a context of a multicast service from the second access network device, or receive third information for extracting a user equipment UE context of the terminal from the first access network device from the second access network device. For example, the receiving unit 1002 may support the communication device 100 to perform S503.

A processing unit 1001, configured to update a context of the multicast service according to the second information; or, updating the number of the terminals joining the multicast group through the first access network device according to the third information. For example, the processing unit 1001 and/or the transmitting unit 1003 may support the communication device to perform S504a and S504b.

Specifically, all relevant contents of each step related to the method embodiment shown in fig. 5a to 5b may be referred to the functional description of the corresponding functional module, and are not described herein again. The communication apparatus 100 is configured to perform the function of the first access network device in the communication method of the multicast service shown in the method shown in fig. 5 a-5 b, so that the same effect as the communication method of the multicast service described above can be achieved.

In another possible design, the processing unit 1001 is configured to allocate a radio network temporary identifier of a multicast service according to the identifier information of the multicast service, and obtain scrambled downlink control information according to the radio network temporary identifier of the multicast service. For example, the processing unit 1001 may be used to support the communication device 100 to perform S601 and S602.

A sending unit 1003, configured to send the fourth information and the scrambled downlink control information. For example, the transmitting unit 1003 may support the communication device 100 to perform S603.

Specifically, all relevant contents of each step related to the method embodiment shown in fig. 6 may be referred to the functional description of the corresponding functional module, and are not described herein again. The communication apparatus 100 is configured to perform the function of the access network device in the communication method of the multicast service shown in the method shown in fig. 6, so that the same effect as that of the communication method of the multicast service described above can be achieved.

As still another implementation, the communication apparatus 100 shown in fig. 10 includes: a processing module and a communication module. The processing module is configured to control and manage operations of the communication apparatus 100, and execute S504a, S504b, S601, S602, and the like. The communication module may integrate the functions of the receiving unit 1001 and the sending unit 1002, such as performing S603 and the like, and communication with other network entities, such as the functional modules or the network entities shown in fig. 4 or fig. 5 a. Further, the communication device 100 may further include a storage module for storing instructions and/or data. The instructions, when executed by the processing module, cause the processing module to implement the first access network device/access network device method described above.

The processing module may be a processor, a controller, a module, or a circuit. Which may implement or perform the various illustrative logical blocks described in connection with the disclosure of the embodiments of the application. The communication module may be a transceiver circuit, a pin, an interface circuit, a bus interface, a communication interface, or the like. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication device 100 according to the embodiment of the present application may be the communication device 400 shown in fig. 4.

In the embodiments of the present application, the processor may be a general-purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, and may implement or execute the methods, steps, and logic blocks disclosed in the embodiments of the present application. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in a processor.

In the embodiment of the present application, the memory may be a nonvolatile memory, such as a Hard Disk Drive (HDD) or a solid-state drive (SSD), and may also be a volatile memory, for example, a random-access memory (RAM). The memory is any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited to such. The memory in the embodiments of the present application may also be a circuit or any other device capable of performing a storage function to store instructions and/or data.

Fig. 11 is a structural diagram of a communication system according to an embodiment of the present application, and as shown in fig. 11, the communication system may include: a terminal 110, a first access network device 111, and a second access network device 112. The terminal 110 may be in an inactive state. It should be noted that fig. 11 is only an exemplary diagram, and the embodiment of the present application does not limit the network elements included in the communication system shown in fig. 11 and the number of the network elements.

The terminal 110 has the functions of the terminal in the methods shown in fig. 5a to 5 b. The first access network device 111 has the functionality of the first access network device in the method illustrated in fig. 5a to 5b described above. The second access network device 112 has the functionality of the second access network device in the method described above in fig. 5 a-5 b.

Fig. 12 is a block diagram of a communication system according to an embodiment of the present application, and as shown in fig. 12, the communication system may include: a plurality of terminals 120, an access network device 121. Among the plurality of terminals 120, there is a terminal in an inactive state or an idle state. It should be noted that fig. 12 is only an exemplary diagram, and the embodiment of the present application does not limit the network elements included in the communication system shown in fig. 12 and the number of the network elements.

The terminal 120 has the functions of the terminal in the method shown in fig. 6. The access network device 121 has the functions of the access network device in the method of fig. 6 described above.

In the embodiments of the present application, "/" may indicate a relationship in which the objects associated before and after are "or", for example, a/B may indicate a or B; "and/or" may be used to describe that there are three relationships for the associated object, e.g., A and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. For convenience in describing the technical solutions of the embodiments of the present application, in the embodiments of the present application, terms such as "first" and "second" may be used to distinguish technical features having the same or similar functions. The terms "first", "second", and the like do not necessarily limit the number and execution order, and the terms "first", "second", and the like do not necessarily differ. In the embodiments of the present application, the words "exemplary" or "such as" are used to indicate examples, illustrations or illustrations, and any embodiment or design described as "exemplary" or "e.g.," should not be construed as preferred or advantageous over other embodiments or designs. The use of the terms "exemplary" or "such as" are intended to present relevant concepts in a concrete fashion for ease of understanding.

In the embodiment of the present application, for a technical feature, the technical features in the technical feature are distinguished by "first", "second", "third", "a", "B", "C", and "D", and the like, and the technical features described in "first", "second", "third", "a", "B", "C", and "D" are not in a sequential order or a size order.

It should be understood that in the embodiment of the present application, "B corresponding to a" means that B is associated with a. For example, B may be determined from A. It should also be understood that determining B from a does not mean determining B from a alone, but may also be determined from a and/or other information. In addition, the term "connect" in the embodiment of the present application refers to various connection manners such as direct connection or indirect connection, so as to implement communication between devices, which is not limited in this embodiment of the present application.

The "transmission" appearing in the embodiments of the present application refers to a bidirectional transmission, including actions of transmission and/or reception, unless otherwise specified. Specifically, "transmission" in the embodiment of the present application includes transmission of data, reception of data, or both transmission of data and reception of data. Alternatively, the data transmission herein includes uplink and/or downlink data transmission. The data may include channels and/or signals, uplink data transmission, i.e., uplink channel and/or uplink signal transmission, and downlink data transmission, i.e., downlink channel and/or downlink signal transmission. In the embodiments of the present application, "network" and "system" represent the same concept, and a communication system is a communication network.

The division of the modules in the embodiments of the present application is schematic, and is only a logical function division, and in actual implementation, there may be another division manner, and in addition, each functional module in each embodiment of the present application may be integrated in one processor, or may exist alone physically, or two or more modules are integrated in one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode.

The technical solutions provided in the embodiments of the present application may be wholly or partially implemented by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. The procedures or functions described in accordance with the embodiments of the application are all or partially generated when the computer program instructions are loaded and executed on a computer. The computer may be a general purpose computer, special purpose computer, computer network, wireless control device, access network apparatus, terminal, or other programmable device. The computer instructions may be stored on a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website, computer, server, or data center to another website, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., digital Video Disk (DVD)), or a semiconductor medium, among others.

In the embodiments of the present application, the embodiments may refer to each other, for example, methods and/or terms between the embodiments of the method may refer to each other, for example, functions and/or terms between the embodiments of the apparatus and the embodiments of the method may refer to each other, without logical contradiction.

The above description is only a specific implementation of the embodiments of the present application, but the scope of the embodiments of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the embodiments of the present application should be covered by the scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application shall be subject to the protection scope of the claims.

Claims

1. A communication method of multicast service is characterized in that the method is applied to a terminal in a Radio Resource Control (RRC) inactive state to move from a first access network device to a second access network device, and the terminal joins in a multicast group corresponding to the multicast service through the first access network device, and the method comprises the following steps:

when the terminal determines that the terminal is located outside the first area, the terminal sends first information to the second access network device, wherein the first information is used for informing that the terminal moves out of the first area, and the first area is a service area of the first access network device.

2. The method of claim 1,

the first information comprises identification information of the multicast service.

3. The method according to claim 1 or 2, wherein the first information further comprises a radio network temporary identity of the terminal, and the radio network temporary identity of the terminal comprises an identity of the first access network device.

4. The method according to any of claims 1-3, wherein the first information is carried in a first radio resource control, RRC, message;

wherein the first RRC message is used for requesting to recover the RRC connection of the terminal; or the first RRC message is used to trigger the second access network device to send second information or third information to the first access network device;

the second information is used for updating the context of the multicast service, and the third information is used for extracting the UE context of the terminal from the first access network equipment.

5. The method according to any of claims 1-4, wherein the terminal sends the first information to the second access network device, comprising:

and the terminal sends the first information to the second access network equipment through a signaling radio bearer.

6. The method according to any one of claims 1-5, further comprising:

the terminal receives information from the first area of the first access network device.

7. The method of claim 6, wherein the information of the first region is carried in a second RRC message; wherein the second RRC message is used for suspending RRC connection of the terminal.

8. A communication method of multicast service is applied to a terminal moving from a first access network device to a second access network device, and the terminal is in a Radio Resource Control (RRC) inactive state, and the method comprises the following steps:

second access network equipment receives first information from a terminal, wherein the first information is used for informing the terminal to move out of the first area, and the first area is a service area of the first access network equipment;

and the second access network equipment sends second information or third information to the first access network equipment according to the first information, wherein the second information is used for updating the context of the multicast service, and the third information is used for extracting the UE context of the terminal from the first access network equipment.

9. The method of claim 8,

the first information includes identification information of the multicast service.

10. The method according to claim 8 or 9,

the first information further comprises a radio network temporary identity of the terminal,

the radio network temporary identifier of the terminal comprises the identifier of the first access network equipment.

11. The method of claim 10, wherein the second access network device sends the second information or the third information to the first access network device according to the first information, and wherein the sending comprises:

and the second access network equipment sends the second information or the third information to the first access network equipment according to the identifier of the first access network equipment.

12. The method according to any one of claims 8 to 11,

the second information includes identification information of the multicast service.

13. The method according to any one of claims 8 to 12,

the second information and the third information are carried in a request for extracting UE context; or,

the second information and the third information are carried in an Xn message.

14. A communication method of multicast service is characterized in that the method is applied to a terminal in a Radio Resource Control (RRC) inactive state moving from a first access network device to a second access network device, and the terminal joins in a multicast group corresponding to the multicast service through the first access network device, and the method comprises the following steps:

the first access network equipment receives second information from the second access network equipment; wherein the second information is used for updating the context of the multicast service;

and the first access network equipment updates the context of the multicast service according to the second information.

15. The method of claim 14,

16. The method according to claim 14 or 15, wherein the first access network device updates the context of the multicast service according to the second information, including:

and the first access network equipment updates the number of the terminals which join the multicast group through the first access network equipment in the context of the multicast service according to the second information.

17. The method according to claim 15 or 16, wherein the second information further includes identification information of the terminal, and the first access network device updates the context of the multicast service according to the second information, including:

and the first access network equipment deletes the identification information of the terminal in the context of the multicast service according to the second information.

18. The method according to claim 14, wherein the second information comprises a radio network temporary identifier of the terminal; the first access network device updates the context of the multicast service according to the second information, and the updating includes:

the first access network equipment acquires the identification information of the multicast service in the context of User Equipment (UE) of the terminal according to the radio network temporary identification of the terminal;

and the first access network equipment deletes the identification information of the terminal in the context of the multicast service according to the acquired identification information of the multicast service, or updates the number of the terminals which join the multicast group through the first access network equipment in the context of the multicast service.

19. The method according to any one of claims 14 to 18,

the second information is carried in a request for extracting a UE context or an Xn message.

20. A communication method of multicast service is characterized in that the method is applied to a terminal in a Radio Resource Control (RRC) inactive state moving from a first access network device to a second access network device, and the terminal joins in a multicast group corresponding to the multicast service through the first access network device, and the method comprises the following steps:

the first access network device receiving third information from a second access network device; wherein the third information is used for extracting a User Equipment (UE) context of a terminal from the first access network equipment;

and the first access network equipment updates the number of the terminals which join the multicast group through the first access network equipment according to the third information.

21. The method of claim 20, further comprising:

and the first access network equipment deletes the identification information of the multicast service in the context of the User Equipment (UE) of the terminal.

22. The method of claim 20 or 21,

the third information includes identification information of the multicast service.

23. The method of any of claims 20-22, wherein the first access network device updating the number of terminals joining the multicast group via the first access network device according to the third information comprises:

the first access network equipment acquires the UE context of the terminal according to the third information, wherein the UE context of the terminal comprises the identification information of the multicast service;

and the first access network equipment updates the number of the terminals which join the multicast group through the first access network equipment in the context of the multicast service according to the identification information of the multicast service.

24. The method according to any one of claims 14-23, characterized in that the method further comprises:

and the first access network equipment sends information of a first area to the terminal, wherein the first area is a service area of the first access network equipment.

25. A method for communicating multicast traffic, the method comprising:

the access network equipment distributes a wireless network temporary identifier of the multicast service according to the identifier information of the multicast service;

the access network equipment acquires scrambled downlink control information according to the wireless network temporary identifier of the multicast service;

and the access network equipment sends fourth information and the scrambled downlink control information, wherein the fourth information comprises the identification information of the multicast service and the radio network temporary identification of the multicast service.

26. The method of claim 25,

the fourth information is carried in a system information block SIB; or,

the fourth information is carried in a master information block MIB; or,

the fourth information is carried in a paging message.

27. The method of claim 25, wherein the access network device sending the fourth information comprises:

and the access network equipment sends the fourth information through signaling a radio bearer (SRB).

28. A method for communicating multicast traffic, the method comprising:

the terminal receives fourth information and scrambled downlink control information from access network equipment, wherein the fourth information comprises identification information of a multicast service and a radio network temporary identification of the multicast service;

and the terminal receives the data of the multicast service from the access network equipment according to the fourth information and the scrambled downlink control information.

29. The method of claim 28, wherein the receiving, by the terminal, the data of the multicast service from the access network device according to the fourth information and the scrambled downlink control information comprises:

when the terminal is interested in the multicast service, the terminal obtains descrambled downlink control information according to the wireless network temporary identifier of the multicast service;

and the terminal receives the data of the multicast service from the access network equipment according to the descrambled downlink control information.

30. The method of claim 28 or 29,

the fourth information is carried in a system information block SIB; or,

the fourth information is carried in a master information block MIB; or,

the fourth information is carried in a paging message.

31. The method according to claim 28 or 29, wherein the terminal receives fourth information from the access network device, comprising:

and the terminal receives the fourth information from the access network equipment through a Signaling Radio Bearer (SRB).

32. A communication system, wherein the communication system is applied to a terminal in an RRC inactive state of RRC inactive state moving from a first access network device to a second access network device, and the terminal joins a multicast group corresponding to a multicast service through the first access network device, the communication system comprising:

a terminal, configured to send first information to the second access network device when it is determined that the terminal is located outside a first area, where the first information is used to notify that the terminal moves out of the first area, and the first area is a service area of the first access network device;

the second access network device is configured to receive the first information from the terminal, and send second information or third information to the first access network device according to the first information, where the second information is used to update a context of the multicast service, and the third information is used to extract a UE context of the terminal from the first access network device;

the first access network device is configured to receive the second information from the second access network device, and update the context of the multicast service according to the second information; or receiving the third information from the second access network device, and updating the number of the terminals joining the multicast group through the first access network device according to the third information.

33. A communication system, characterized in that the communication system comprises:

the access network equipment is used for distributing the wireless network temporary identifier of the multicast service according to the identifier information of the multicast service, acquiring scrambled downlink control information according to the wireless network temporary identifier of the multicast service, and sending fourth information and the scrambled downlink control information, wherein the fourth information comprises the identifier information of the multicast service and the wireless network temporary identifier of the multicast service;

and the terminal is used for receiving the fourth information and the scrambled downlink control information from the access network equipment and receiving the data of the multicast service from the access network equipment according to the fourth information and the scrambled downlink control information.

34. A communication device, comprising a processor and a memory,

the memory to store computer program code, the computer program code comprising computer instructions;

the processor, configured to, when the processor executes the computer instructions, perform the communication method according to any one of claims 1 to 7, or perform the communication method according to any one of claims 8 to 12, or perform the communication method according to any one of claims 14 to 19, or perform the communication method according to any one of claims 20 to 24, or perform the communication method according to any one of claims 26 to 27, or perform the communication method according to any one of claims 28 to 31.

35. A computer readable storage medium, wherein the computer readable storage medium stores computer instructions which, when executed on a computer, cause the computer to perform the communication method of any one of claims 1-7, or the communication method of any one of claims 8-12, or the communication method of any one of claims 14-19, or the communication method of any one of claims 20-24, or the communication method of any one of claims 25-27, or the communication method of any one of claims 28-31.

36. A computer program product comprising computer instructions which, when run on a computer, cause the computer to perform the communication method of any one of claims 1-7, or the communication method of any one of claims 8-12, or the communication method of any one of claims 14-19, or the communication method of any one of claims 20-24, or the communication method of any one of claims 26-27, or the communication method of any one of claims 28-31.

37. A chip coupled with a memory for reading and executing program instructions stored in the memory for implementing a communication method according to any one of claims 1 to 7, or for executing a communication method according to any one of claims 8 to 12, or for executing a communication method according to any one of claims 14 to 19, or for executing a communication method according to any one of claims 20 to 24, or for executing a communication method according to any one of claims 26 to 27, or for executing a communication method according to any one of claims 28 to 31.