Point-to-multipoint data transmission method, device, electronic device and storage medium

Abstract

An embodiment of the present application provides a point-to-multipoint data transmission method, apparatus, electronic device, and storage medium. The method includes: determining a root user plane function (UPF) network element; sending a first N4 session establishment request message to the root UPF network element; the first N4 session establishment request message includes a first data forwarding rule; the first data forwarding rule is used to indicate the way for the root UPF network element to perform multicast data forwarding; the multicast data is point-to-multipoint T2mT data in a space-air-ground integrated network. The point-to-multipoint data transmission method, apparatus, electronic device, and storage medium provided by the embodiments of the present application, by introducing a root UPF network element, the root UPF network element performs data transmission with other UPFs in the multicast group respectively, without the need to re-establish the N9 tunnel between UPF network elements, effectively utilizes resources, and saves signaling overhead and resource consumption.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a point-to-multipoint data transmission method, apparatus, electronic device, and storage medium. Background Art

[0002] In the existing 5G multicast / broadcast service (5MBS) technology, multicast data transmission is carried out between a 5G base station (gNB) and a User Plane Function (UPF) network element by establishing a multicast session, and data transmission is carried out by establishing a unicast tunnel through a Protocol Data Unit (PDU) session. Data transmission between a terminal / user equipment (User Equipment, UE) and a gNB is carried out using a Radio Bearer (RB).

[0003] If the existing general technology on the ground is used to support the Terminal to Multiple Terminal (T2mT) service in the space-air-ground integrated network, when any UE in the multicast group sends a multicast request, tunnels need to be established between the on-star UPF network elements corresponding to the UEs in the multicast group and between the on-star UPF network element and the gNB. When different UEs in the multicast group send multicast data, if the N9 tunnel between the corresponding UPF network elements is not established, the N9 tunnel between the UPF network elements needs to be re-established, which causes resource waste for the satellites in the space-air-ground integrated network. Summary of the Invention

[0004] Embodiments of this application provide a point-to-multipoint data transmission method, apparatus, electronic device, and storage medium, which are used to solve the technical problem of low resource utilization rate in the process of point-to-multipoint data transmission in the space-air-ground integrated network.

[0005] In a first aspect, embodiments of this application provide a point-to-multipoint data transmission method, including:

[0006] Determine a root User Plane Function (UPF) network element;

[0007] Send a first N4 session establishment request message to the root UPF network element; the first N4 session establishment request message includes a first data forwarding rule; the first data forwarding rule is used to indicate the way for the root UPF network element to perform multicast data forwarding; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network.

[0008] Optionally, for the point-to-multipoint data transmission method according to an embodiment of the present application, the determination of the root user plane function UPF network element includes:

[0009] Regarding the UPF network element directly connected to all UPF network elements in the multicast group as the root UPF network element.

[0010] Optionally, for the point-to-multipoint data transmission method according to an embodiment of the present application, the determination of the root user plane function UPF network element includes:

[0011] Regarding the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group as the root UPF network element.

[0012] Optionally, for the point-to-multipoint data transmission method according to an embodiment of the present application, the determination of the root user plane function UPF network element includes:

[0013] Regarding the UPF network element with the least user plane traffic as the root UPF network element.

[0014] Optionally, for the point-to-multipoint data transmission method according to an embodiment of the present application, the first data forwarding rule includes:

[0015] If the root UPF network element receives multicast data sent by the gNB directly connected to the root UPF network element, the root UPF network element sends the multicast data to other UPF network elements within the multicast group;

[0016] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group;

[0017] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, and the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0018] Optionally, for the point-to-multipoint data transmission method according to an embodiment of the present application, after determining the root user plane function UPF network element, it further includes:

[0019] Sending a second N4 session establishment request message to other UPF network elements within the multicast group; the second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the way for other UPF network elements within the multicast group to forward multicast data.

[0020] Optionally, for the point-to-multipoint data transmission method according to an embodiment of the present application, the second data forwarding rule includes:

[0021] If the other UPF network element receives the multicast data sent by the root UPF network element, the other UPF network element sends the multicast data to the gNB;

[0022] If the other UPF network element receives the multicast data sent by the gNB directly connected to the other UPF network element, the other UPF network element sends the multicast data to the root UPF network element;

[0023] If the other UPF network element receives the unicast data sent by the gNB directly connected to the other UPF network element, the other UPF network element sends the unicast data to the destination UPF network element or the gNB.

[0024] In a second aspect, an embodiment of the present application provides a point-to-multipoint data transmission method, including:

[0025] Receiving a first N4 session establishment request message sent by a session management function SMF network element; the first N4 session establishment request message includes a first data forwarding rule;

[0026] Forwarding multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in the air-ground integrated network.

[0027] Optionally, for the point-to-multipoint data transmission method according to an embodiment of the present application, the forwarding multicast data according to the first data forwarding rule includes:

[0028] Receiving multicast data sent by a base station gNB directly connected to a root user plane function UPF network element;

[0029] Sending the multicast data to other UPF network elements within the multicast group.

[0030] Optionally, for the point-to-multipoint data transmission method according to an embodiment of the present application, the forwarding multicast data according to the first data forwarding rule includes:

[0031] Receiving multicast data sent by any UPF network element within the multicast group;

[0032] Sending the multicast data to other UPF network elements within the multicast group.

[0033] Optionally, for the point-to-multipoint data transmission method according to an embodiment of the present application, the forwarding multicast data according to the first data forwarding rule includes:

[0034] Receiving multicast data sent by any UPF network element within the multicast group;

[0035] If the UE under the gNB directly connected to the root UPF network element is in the in-group UE list of the multicast group, the multicast data is sent to other UPF network elements in the multicast group and the gNB directly connected to the root UPF network element.

[0036] In a third aspect, an embodiment of the present application provides a point-to-multipoint data transmission method, including:

[0037] Receiving a second N4 session establishment request message sent by a session management function SMF network element; the second N4 session establishment request message includes a second data forwarding rule; the second data forwarding rule is used to indicate the way of multicast data forwarding by other UPF network elements in the multicast group; the multicast data is point-to-multipoint T2mT data in the air-ground integrated network;

[0038] Forwarding the multicast data according to the second data forwarding rule.

[0039] Optionally, in the point-to-multipoint data transmission method according to an embodiment of the present application, the forwarding the multicast data according to the second data forwarding rule includes:

[0040] Receiving multicast data sent by a directly connected base station gNB;

[0041] Sending the multicast data to a root user plane function UPF network element.

[0042] Optionally, in the point-to-multipoint data transmission method according to an embodiment of the present application, the forwarding the multicast data according to the second data forwarding rule includes:

[0043] Receiving multicast data sent by a root UPF network element;

[0044] Sending the multicast data to the gNB.

[0045] In a fourth aspect, an embodiment of the present application provides a point-to-multipoint data transmission method, including:

[0046] Receiving multicast data sent by a user plane function UPF network element; the multicast data is point-to-multipoint T2mT data in the air-ground integrated network;

[0047] If it is determined that the radio bearer of the unicast session existing between the terminal UE meets the quality of service QoS of the multicast session, the radio bearer of the unicast session is multiplexed, and the multicast data is sent to the UE.

[0048] Optionally, in the point-to-multipoint data transmission method according to an embodiment of the present application, after receiving the multicast data sent by the user plane function UPF network element, it further includes:

[0049] If it is determined that there is no radio bearer for the unicast session with the UE, or the radio bearer of the unicast session existing with the UE does not meet the QoS of the multicast session, a radio bearer with the UE is established, and the multicast data is sent to the UE.

[0050] Optionally, in the point-to-multipoint data transmission method according to an embodiment of the present application, the UPF network element is a root UPF network element.

[0051] In a fifth aspect, an embodiment of the present application provides a session management function SMF network element, including a memory, a transceiver, and a processor;

[0052] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations:

[0053] Determine the root user plane function UPF network element;

[0054] Send a first N4 session establishment request message to the root UPF network element; the first N4 session establishment request message contains a first data forwarding rule; the first data forwarding rule is used to indicate the way for the root UPF network element to forward multicast data; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network.

[0055] Optionally, in the SMF network element according to an embodiment of the present application, the determining the root user plane function UPF network element includes:

[0056] Taking the UPF network element directly connected to all UPF network elements in the multicast group as the root UPF network element.

[0057] Optionally, in the SMF network element according to an embodiment of the present application, the determining the root user plane function UPF network element includes:

[0058] Taking the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group as the root UPF network element.

[0059] Optionally, in the SMF network element according to an embodiment of the present application, the determining the root user plane function UPF network element includes:

[0060] Taking the UPF network element with the least user plane traffic as the root UPF network element.

[0061] Optionally, in the SMF network element according to an embodiment of the present application, the first data forwarding rule includes:

[0062] If the root UPF network element receives multicast data sent by a gNB directly connected to the root UPF network element, the root UPF network element sends the multicast data to other UPF network elements within the multicast group;

[0063] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group;

[0064] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, and the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0065] Optionally, for the SMF network element according to an embodiment of the present application, after determining the root user plane function UPF network element, it further includes:

[0066] Sending a second N4 session establishment request message to other UPF network elements within the multicast group; the second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the manner in which other UPF network elements within the multicast group forward multicast data.

[0067] Optionally, for the SMF network element according to an embodiment of the present application, the second data forwarding rule includes:

[0068] If the other UPF network element receives multicast data sent by the root UPF network element, the other UPF network element sends the multicast data to the gNB;

[0069] If the other UPF network element receives multicast data sent by a gNB directly connected to the other UPF network element, the other UPF network element sends the multicast data to the root UPF network element;

[0070] If the other UPF network element receives unicast data sent by a gNB directly connected to the other UPF network element, the other UPF network element sends the unicast data to the destination UPF network element or the gNB.

[0071] In a sixth aspect, an embodiment of the present application provides a user plane function UPF network element, including a memory, a transceiver, and a processor;

[0072] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations:

[0073] Receive a first N4 session establishment request message sent by a session management function SMF network element; the first N4 session establishment request message includes a first data forwarding rule;

[0074] Forward multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in the air-ground integrated network.

[0075] Optionally, for a UPF network element according to an embodiment of the present application, the forwarding of multicast data according to the first data forwarding rule includes:

[0076] Receive multicast data sent by a base station gNB directly connected to the root user plane function UPF network element;

[0077] Send the multicast data to other UPF network elements within the multicast group.

[0078] Optionally, for a UPF network element according to an embodiment of the present application, the forwarding of multicast data according to the first data forwarding rule includes:

[0079] Receive multicast data sent by any UPF network element within the multicast group;

[0080] Send the multicast data to other UPF network elements within the multicast group.

[0081] Optionally, for a UPF network element according to an embodiment of the present application, the forwarding of multicast data according to the first data forwarding rule includes:

[0082] Receive multicast data sent by any UPF network element within the multicast group;

[0083] If the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, send the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0084] In a seventh aspect, an embodiment of the present application provides a user plane function UPF network element, including a memory, a transceiver, and a processor;

[0085] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations:

[0086] Receive a second N4 session establishment request message sent by a session management function SMF network element; the second N4 session establishment request message includes a second data forwarding rule; the second data forwarding rule is used to indicate the way for other UPF network elements within the multicast group to forward multicast data; the multicast data is point-to-multipoint T2mT data in the air-ground integrated network;

[0087] Forward the multicast data according to the second data forwarding rule.

[0088] Optionally, for a UPF network element according to an embodiment of the present application, the forwarding of the multicast data according to the second data forwarding rule includes:

[0089] Receive the multicast data sent by the directly connected base station gNB;

[0090] Send the multicast data to the root user plane function UPF network element.

[0091] Optionally, for a UPF network element according to an embodiment of the present application, the forwarding of the multicast data according to the second data forwarding rule includes:

[0092] Receive the multicast data sent by the root UPF network element;

[0093] Send the multicast data to the gNB.

[0094] In an eighth aspect, an embodiment of the present application provides a base station, including a memory, a transceiver, and a processor;

[0095] The memory is used to store a computer program; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer program in the memory and perform the following operations:

[0096] Receive the multicast data sent by the user plane function UPF network element; the multicast data is point-to-multipoint T2mT data in the air-ground integrated network;

[0097] If it is determined that the radio bearer of the unicast session existing with the terminal UE meets the quality of service QoS of the multicast session, multiplex the radio bearer of the unicast session and send the multicast data to the UE.

[0098] Optionally, for a base station according to an embodiment of the present application, after receiving the multicast data sent by the user plane function UPF network element, it further includes:

[0099] If it is determined that there is no radio bearer of the unicast session with the UE, or the radio bearer of the unicast session existing with the UE does not meet the QoS of the multicast session, establish a radio bearer with the UE and send the multicast data to the UE.

[0100] Optionally, for a base station according to an embodiment of the present application, the UPF network element is a root UPF network element.

[0101] In a ninth aspect, an embodiment of the present application provides a point-to-multipoint data transmission device, including:

[0102] A determination module, configured to determine a root User Plane Function (UPF) network element;

[0103] A first sending module, configured to send a first N4 session establishment request message to the root UPF network element; the first N4 session establishment request message includes a first data forwarding rule; the first data forwarding rule is used to indicate a multicast data forwarding method of the root UPF network element; the multicast data is point-to-multipoint T2mT data in a space-air-ground integrated network.

[0104] In a tenth aspect, an embodiment of the present application provides a point-to-multipoint data transmission device, including:

[0105] A first receiving module, configured to receive a first N4 session establishment request message sent by a Session Management Function (SMF) network element; the first N4 session establishment request message includes a first data forwarding rule;

[0106] A second sending module, configured to forward multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in a space-air-ground integrated network.

[0107] In an eleventh aspect, an embodiment of the present application provides a point-to-multipoint data transmission device, including:

[0108] A second receiving module, configured to receive a second N4 session establishment request message sent by a Session Management Function (SMF) network element; the second N4 session establishment request message includes a second data forwarding rule; the second data forwarding rule is used to indicate a multicast data forwarding method of other UPF network elements within a multicast group; the multicast data is point-to-multipoint T2mT data in a space-air-ground integrated network;

[0109] A third sending module, configured to forward multicast data according to the second data forwarding rule.

[0110] In a twelfth aspect, an embodiment of the present application provides a point-to-multipoint data transmission device, including:

[0111] A third receiving module, configured to receive multicast data sent by a User Plane Function (UPF) network element; the multicast data is point-to-multipoint T2mT data in a space-air-ground integrated network;

[0112] A fourth sending module, configured to, if it is determined that a radio bearer of a unicast session existing with a User Equipment (UE) meets the Quality of Service (QoS) of a multicast session, multiplex the radio bearer of the unicast session and send the multicast data to the UE.

[0113] In a thirteenth aspect, an embodiment of the present application further provides a processor-readable storage medium storing a computer program for causing the processor to execute the steps of the point-to-multipoint data transmission method described in the first aspect, second aspect, third aspect, or fourth aspect as described above.

[0114] The point-to-multipoint data transmission method, apparatus, electronic device, and storage medium provided by the embodiments of the present application introduce a root UPF network element. The root UPF network element performs data transmission with other UPFs within the multicast group respectively, without the need to re-establish the N9 tunnel between UPF network elements, effectively utilizing resources and saving signaling overhead and resource consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0115] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0116] Figure 1 It is a schematic diagram of the multicast tunnel establishment process between UPF network elements in the space-air-ground integrated network;

[0117] Figure 2 It is a schematic diagram of the process of transmitting T2mT data using the inter-satellite transmission tunnel in the space-air-ground integrated network;

[0118] Figure 3 It is a schematic diagram of the network architecture for point-to-multipoint data transmission provided by an embodiment of the present application;

[0119] Figure 4 It is a schematic diagram of the point-to-multipoint tunnel establishment process provided by an embodiment of the present application;

[0120] Figure 5 It is one of the schematic diagrams of the process of the point-to-multipoint data transmission method provided by an embodiment of the present application;

[0121] Figure 6 It is another schematic diagram of the process of the point-to-multipoint data transmission method provided by an embodiment of the present application;

[0122] Figure 7 It is a schematic diagram of the data flow of point-to-multipoint data transmission provided by an embodiment of the present application;

[0123] Figure 8 It is a third schematic diagram of the process of the point-to-multipoint data transmission method provided by an embodiment of the present application;

[0124] Figure 9It is the fourth flowchart of the point-to-multipoint data transmission method provided by the embodiments of the present application;

[0125] Figure 10 It is the structural schematic diagram of the SMF network element provided by the embodiments of the application;

[0126] Figure 11 It is the structural schematic diagram of the root UPF network element provided by the embodiments of the application;

[0127] Figure 12 It is the structural schematic diagram of the UPF network element provided by the embodiments of the application;

[0128] Figure 13 It is the structural schematic diagram of the base station provided by the embodiments of the application;

[0129] Figure 14 It is one of the flowchart of the point-to-multipoint data transmission device provided by the embodiments of the present application;

[0130] Figure 15 It is the second flowchart of the point-to-multipoint data transmission device provided by the embodiments of the present application;

[0131] Figure 16 It is the third flowchart of the point-to-multipoint data transmission device provided by the embodiments of the present application;

[0132] Figure 17 It is the fourth flowchart of the point-to-multipoint data transmission device provided by the embodiments of the present application. Detailed implementation manners

[0133] In the existing 5MBS technology, multicast data is transmitted between the gNB and the UPF network element by establishing a multicast session, and unicast tunnels are established through the establishment of PDU sessions for data transmission, where RB is used for data transmission between the UE and the gNB.

[0134] If the existing general ground technology is used to support the T2mT service in the integrated space-air-ground network, then when any UE in the multicast group sends a multicast request, tunnels need to be established between the on-orbit UPF network elements (which can be simply referred to as "UPF network elements in the multicast group") corresponding to the UEs in the multicast group and between the UPF network element and the gNB. When different UEs in the multicast group send multicast data, if the N9 tunnel between the corresponding UPF network elements is not established, the N9 tunnel between the UPF network elements needs to be re-established, which also causes waste of satellite resources for the satellites in the integrated space-air-ground network.

[0135] Figure 1 It is the schematic diagram of the multicast tunnel establishment process between UPF network elements in the integrated space-air-ground network, as Figure 1As shown in the figure, after the UE completes the group call authorization to the T2mT Service Center, it notifies the Session Management Function (SMF network element) to establish a data transmission multicast channel. The method of establishing a tunnel between adjacent satellite UPF network elements using existing technologies is as follows:

[0136] 1. The SMF network element sends an N4 Session Establishment Request to the first User Plane Function UPF1 network element (the UPF1 network element is set on the first satellite SAT1), and the UPF1 network element allocates a Tunnel Endpoint Identifier (TEID).

[0137] 2. The UPF1 network element (SAT1) returns an N4 Session Establishment Response to the SMF network element, and at the same time carries the Core Network Tunnel Information (CN Tunnel Info) containing the allocated TEID information.

[0138] 3. The SMF network element sends an N4 Session Establishment Request to the second User Plane Function UPF2 network element (the UPF2 network element is set on the second satellite SAT2), and at the same time carries the CN Tunnel Info allocated by the UPF1 network element. After receiving this message, the UPF2 network element (SAT2) allocates the TEID of the UPF2 network element (SAT2).

[0139] 4. The UPF2 network element (SAT2) returns an N4 Session Establishment Response to the SMF network element, and at the same time carries the CN Tunnel Info containing the allocated TEID information.

[0140] 5. The SMF network element sends an N4 Session Modification Request to the UPF1 network element (SAT1), carrying the CN Tunnel Info of the UPF2 network element.

[0141] 6. The UPF1 network element (SAT1) sends an N4 Session Modification Response to the SMF network element, completing the establishment of the tunnel between the UPF1 network element (SAT1) and the UPF2 network element (SAT2).

[0142] Figure 2 It is a schematic diagram of the process of transmitting T2mT data using an inter-satellite transmission tunnel in a space-air-ground integrated network, asFigure 2 As shown, in the prior art, when there is a PDU session in the network and the gNB and the UE can perform unicast data transmission through the RB, if a multicast transmission tunnel is established, the RB between the gNB and the UE needs to be re-established. That is, when there are both unicast sessions and multicast sessions at the same time, the unicast and multicast data for data transmission between the UE and the gNB are two RBs, resulting in resource waste.

[0143] During the process of using the inter-satellite transmission tunnel to transmit T2mT data in the space-air-ground integrated network, when different UEs in the multicast group send multicast data, if the N9 tunnel is not established between the corresponding UPF network elements, the N9 tunnel between the UPF network elements needs to be re-established, resulting in resource waste and increasing unnecessary signaling overhead.

[0144] For example, assume that UE1 corresponds to UPF1 network element; UE2 corresponds to UPF2 network element; UE3 corresponds to UPF network element 3; UE4 corresponds to UPF network element 4. When UE1 wants to send data to UE2, UE3, and UE4, tunnels are established between UPF1 network element and UPF2 network element, UPF1 network element and UPF network element 3, and UPF1 network element and UPF network element 4 respectively, so as to achieve the purpose of UE1 sending data to UE2, UE3, and UE4 respectively. However, at this time, if UE2 wants to send data to UE3 and UE4, tunnels need to be re-established between UPF2 network element and UPF network element 3, and UPF2 network element and UPF network element 4, wasting satellite resources.

[0145] The embodiment of the present application proposes a data transmission method from a terminal to multiple terminals / point-to-multipoint, which is different from the "multicast" concept of the existing Multimedia Broadcast Multicast Services (MBMS). In the space-air-ground integrated architecture, the satellite does not yet support T2mT data transmission. The embodiment of the present application introduces a Root UPF network element. The Root UPF network element transmits data with other UPFs in the multicast group respectively, without re-establishing the N9 tunnel between the UPF network elements, effectively utilizing resources, saving signaling overhead and resource consumption, and is of great significance for the development of on-satellite services with relatively scarce resources.

[0146] The multicast data in the present application refers to the T2mT data in the space-air-ground integrated network. The multicast group in the present application refers to a group composed of multiple UEs in the space-air-ground integrated network. The gNB corresponding to the UE in the multicast group is called the gNB in the multicast group, and the UPF network element corresponding to the UE in the multicast group is called the UPF network element in the multicast group.

[0147] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0148] Before performing point-to-multipoint data transmission, it is necessary to establish a point-to-multipoint tunnel.

[0149] Figure 3 It is a schematic diagram of the network architecture for point-to-multipoint data transmission provided by the embodiments of this application. As Figure 3 shown, as an example, the network architecture for point-to-multipoint data transmission includes a T2mT service center, a 5G core network (5GC), a gateway station, a root UPF network element, a UPF1 network element, a UPF2 network element, gNB1, gNB2, UE1, UE2, UE3, and UE4.

[0150] Among them, both the UPF1 network element and the UPF2 network element are UPF network elements within the multicast group. gNB1 is the gNB directly connected to the UPF1 network element, gNB2 is the gNB directly connected to the UPF2 network element, UE1 and UE2 are connected to gNB1, and UE3 and UE4 are connected to gNB2.

[0151] Figure 4 It is a schematic diagram of the point-to-multipoint tunnel establishment process provided by the embodiments of this application. As Figure 4 shown, the process of establishing a point-to-multipoint tunnel includes:

[0152] 1. The T2mT Service Center sends a multicast session establishment request to the SMF network element. The multicast session establishment request message carries the identification code ID of the multicast group and the UE ID list (List).

[0153] 2. The SMF network element determines the Root UPF network element and the ordinary on-star UPF network element.

[0154] (1) The SMF network element determines the Root UPF network element.

[0155] (2) The SMF network element determines the on-star UPF network element.

[0156] The SMF network element selects a session and service continuity mode (Session and Service Continuity Mode, SSCM) and a UPF for the established PDU session.

[0157] 3. The SMF network element sends an N4 Session Establishment Request to the Root UPF network element, which carries information such as the multicast data forwarding rule of the Root UPF network element, the corresponding multicast group address, and the UE ID List.

[0158] The Root UPF network element saves the multicast data forwarding rule and allocates the CN tunnel Info of the TEID.

[0159] 4. The Root UPF network element returns an N4 Session Establishment response to the SMF network element, which carries the CN tunnel Info allocated by the Root UPF network element.

[0160] 5. The SMF network element sends an N4 Session Establishment Request to the UPF1 network element, which carries information such as the multicast data forwarding rule of the UPF1 network element, the corresponding multicast group address, the UE ID List, and the CN tunnel Info of the Root UPF network element.

[0161] 6. The UPF1 network element sends an N4 Session Establishment response to the SMF network element, which carries the CN tunnel Info allocated by the UPF1 network element. The establishment of the multicast tunnel between the Root UPF network element and the UPF1 network element is completed.

[0162] 7. The SMF network element sends an N4 Session Establishment Request to the UPF2 network element, which carries information such as the multicast data forwarding rule of the UPF2 network element, the corresponding multicast group address, the UE ID List, and the CN tunnel Info of the Root UPF network element.

[0163] 8. The UPF2 network element sends an N4 Session Establishment response to the SMF network element, which carries the CN tunnel Info allocated by the UPF2 network element. The establishment of the multicast tunnel between the Root UPF network element and the UPF2 network element is completed.

[0164] 9. Establish an N3 tunnel between the gNB1 and the UPF1 network element.

[0165] The UPF configures the user plane and notifies the radio access network (RAN) of the N3 CN Tunnel Info through the SMF and the Access and Mobility Management Function (AMF). The RAN allocates the N3 access network tunnel information (N3 AN Tunnel Info) and notifies this information to the UPF through the AMF and the SMF. The N3 tunnel is established.

[0166] 10. The SMF network element sends an N2 message (N2 Info) to gNB1, which carries the multicast tunnel information, multicast group address, UE ID List, and Quality of Service (QoS) information of the multicast session between the UPF1 network element and the Root UPF network element.

[0167] 11. After receiving the N2 message, gNB1 determines whether there is an established radio bearer (RB) of the unicast session between gNB1 and the UE.

[0168] If an RB of the unicast session has been established between gNB1 and the UE, gNB1 determines whether the RB of the unicast session can be reused (or referred to as "multiplexed") according to the QoS of the multicast session. If it can be reused, gNB1 binds the established multicast tunnel between the UPF1 network element and gNB1 to the RB of the unicast session.

[0169] 12. If there is no established RB of the unicast session between gNB1 and the UE, or the established RB of the unicast session cannot be reused, the PDU session establishment process is first performed to complete the establishment of the RB of the unicast session between gNB1 and the UE, and then gNB1 binds the established multicast tunnel between the UPF1 network element and gNB1 to the RB of the unicast session.

[0170] 13. Establish the N3 tunnel between gNB2 and the UPF2 network element. The method refers to protocol TS23502.

[0171] 14. The SMF network element sends an N2 message (N2 Info) to gNB2, which carries the multicast tunnel information, multicast group address, UE ID List, and Quality of Service (QoS) information of the multicast session between the UPF2 network element and the Root UPF network element.

[0172] 15. After receiving the N2 message, gNB2 determines whether there is an established radio bearer (RB) of the unicast session between gNB2 and the UE.

[0173] If an RB for a unicast session has been established between gNB2 and the UE, gNB2 determines whether the RB of the unicast session can be reused (or "multiplexed") based on the QoS of the multicast session. If it can be reused, gNB2 binds the multicast tunnel between the established UPF2 network element and gNB2 to the RB of the unicast session.

[0174] 16. If an RB for a unicast session has not been established between gNB2 and the UE, or the established RB of the unicast session cannot be reused, the PDU session establishment process is first performed to complete the establishment of the RB of the unicast session between gNB2 and the UE, and then gNB2 binds the multicast tunnel between the established UPF2 network element and gNB2 to the RB of the unicast session.

[0175] When the gNB receives multicast data from the UPF network element, the gNB forwards the multicast data to the corresponding UE through the RB.

[0176] Figure 5 It is one of the flow diagrams of the point-to-multipoint data transmission method provided by the embodiments of the present application. As Figure 5 shown, a point-to-multipoint data transmission method provided by the embodiments of the present application, the execution entity of which can be an SMF network element. The method includes:

[0177] Step 501, determine the root user plane function UPF network element.

[0178] Specifically, before performing point-to-multipoint data transmission, a point-to-multipoint tunnel needs to be established, and the SMF network element determines the root UPF network element during the establishment process of the point-to-multipoint tunnel. The establishment process of the point-to-multipoint tunnel is as described above and will not be elaborated here.

[0179] The root UPF network element is used to receive multicast data and forward the multicast data to the UPF network elements within the multicast group.

[0180] For example, the SMF network element can determine the Root UPF network element according to at least one of the following rules:

[0181] a. The Root UPF network element is directly connected to all UPF network elements within the multicast group;

[0182] b. The Root UPF network element is the UPF network element with the largest number of UEs included in the directly connected gNBs within the multicast group;

[0183] c. The Root UPF network element is the UPF network element with the least user plane traffic;

[0184] d. The Root UPF network element is one of the UPF network elements within the multicast group;

[0185] e. The Root UPF network element is a UPF network element outside the multicast group.

[0186] Step 502: Send a first N4 session establishment request message to the root UPF network element; the first N4 session establishment request message contains a first data forwarding rule; the first data forwarding rule is used to indicate the multicast data forwarding method of the root UPF network element; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network.

[0187] Specifically, after the SMF network element determines the root UPF network element, it sends a first N4 session establishment request message to the root UPF network element, and the first N4 session establishment request message contains a first data forwarding rule. The first data forwarding rule is used to indicate the multicast data forwarding method of the root UPF network element. The multicast data in the embodiments of the present application can be T2mT data in the space-air-ground integrated network.

[0188] The root UPF network element receives the first N4 session establishment request message sent by the SMF network element.

[0189] When there is multicast data to be transmitted, the root UPF network element forwards the multicast data according to the first data forwarding rule.

[0190] For example, the multicast data forwarding rule of the Root UPF network element may include the following content:

[0191] If the root UPF network element receives multicast data sent by a gNB directly connected to the root UPF network element, the root UPF network element refers to information such as the multicast group address and the UE ID List, and sends the multicast data to other UPF network elements in the multicast group;

[0192] If the root UPF network element receives multicast data sent by any UPF network element in the multicast group, the root UPF network element refers to information such as the multicast group address and the UE ID List, and sends the multicast data to other UPF network elements in the multicast group;

[0193] If the root UPF network element receives multicast data sent by any UPF network element in the multicast group, and the UE under the gNB directly connected to the root UPF network element is in the UE list in the multicast group, the root UPF network element refers to information such as the multicast group address and the UE ID List, and sends the multicast data to other UPF network elements in the multicast group and the gNB directly connected to the root UPF network element.

[0194] The point-to-multipoint data transmission method provided by the embodiments of the present application, by introducing a root UPF network element, the root UPF network element respectively performs data transmission with other UPFs in the multicast group, without the need to re-establish the N9 tunnel between UPF network elements, effectively utilizes resources, and saves signaling overhead and resource consumption.

[0195] Optionally, the determination of the root User Plane Function (UPF) network element includes:

[0196] Regarding the UPF network element that is directly connected to all UPF network elements in the multicast group as the root UPF network element.

[0197] Specifically, in the embodiments of this application, the UPF network element that is directly connected to all UPF network elements in the multicast group is regarded as the root UPF network element.

[0198] The embodiments of this application can reuse as many established tunnels between UPF network elements as possible, avoiding the re - establishment of multicast tunnels and improving efficiency.

[0199] Optionally, the determination of the root User Plane Function (UPF) network element includes:

[0200] Regarding the UPF network element with the largest number of terminal User Equipments (UEs) among the UPF network elements directly connected to the gNBs within the multicast group as the root UPF network element.

[0201] Specifically, in the embodiments of this application, the UPF network element with the largest number of UEs among the UPF network elements directly connected to the gNBs within the multicast group is regarded as the root UPF network element.

[0202] In the embodiments of this application, when a UE under a gNB directly connected to the root UPF network element needs to send multicast data, it can be directly sent to other UPF network elements in the multicast group through the root UPF network element. This avoids the situation where when a UE under a gNB not directly connected to the root UPF network element sends multicast data, the multicast data is first sent to the UPF network element, then forwarded by the UPF network element to the root UPF network element, and then sent to other UPF network elements in the multicast group through the root UPF network element, thus minimizing the data forwarding between UPF network elements and improving efficiency.

[0203] Optionally, the determination of the root User Plane Function (UPF) network element includes:

[0204] Regarding the UPF network element with the least user - plane traffic as the root UPF network element.

[0205] Specifically, in the embodiments of this application, the UPF network element with the least user - plane traffic is regarded as the root UPF network element.

[0206] In the embodiments of this application, regarding the UPF network element with the least user - plane traffic as the root UPF network element can ensure that the root UPF network element has sufficient computing resources and storage resources as much as possible, improving efficiency.

[0207] Optionally, the first data forwarding rule includes:

[0208] If the root UPF network element receives multicast data sent by a gNB directly connected to the root UPF network element, the root UPF network element sends the multicast data to other UPF network elements within the multicast group;

[0209] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group;

[0210] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, and the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0211] Specifically, in the embodiments of the present application, the multicast data forwarding rules of the root UPF network element include the following:

[0212] If the root UPF network element receives multicast data sent by a gNB directly connected to the root UPF network element, the root UPF network element refers to information such as the multicast group address and the UE ID List, and sends the multicast data to other UPF network elements within the multicast group;

[0213] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, the root UPF network element refers to information such as the multicast group address and the UE ID List, and sends the multicast data to other UPF network elements within the multicast group;

[0214] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, and the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, the root UPF network element refers to information such as the multicast group address and the UE ID List, and sends the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0215] In the embodiments of the present application, through the defined forwarding rules, the root UPF network element performs data transmission with other UPFs within the multicast group respectively, without re - establishing the N9 tunnel between UPF network elements, effectively utilizing resources and saving signaling overhead and resource consumption.

[0216] Optionally, after determining the root user plane function UPF network element, it further includes:

[0217] Sending a second N4 session establishment request message to other UPF network elements within the multicast group; the second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the way for other UPF network elements within the multicast group to forward multicast data.

[0218] Specifically, in the embodiments of the present application, after the SMF network element determines the root UPF network element, it is also necessary to send a second N4 session establishment request message to other UPF network elements in the multicast group.

[0219] The second N4 session establishment request message includes a second data forwarding rule.

[0220] The second data forwarding rule is used to indicate the way for other UPF network elements in the multicast group to forward multicast data.

[0221] For example, the multicast data forwarding rules of other UPF network elements in the multicast group may include the following content:

[0222] If other UPF network elements receive multicast data sent by the root UPF network element, then other UPF network elements refer to information such as the multicast group address and the UE ID List, and send the multicast data to the gNB through the established N3 tunnel;

[0223] If other UPF network elements receive multicast data sent by the gNB directly connected to them, then other UPF network elements refer to information such as the multicast group address and the UE ID List, and send the multicast data to the root UPF network element through the multicast tunnel;

[0224] If other UPF network elements receive unicast data sent by the gNB directly connected to them, then other UPF network elements send the unicast data to the destination UPF network element or the gNB according to the unicast address through the unicast tunnel.

[0225] In the embodiments of the present application, by defining well-defined forwarding rules, other UPF network elements in the multicast group forward data according to the forwarding rules, effectively utilizing resources and saving signaling overhead and resource consumption.

[0226] Optionally, the second data forwarding rule includes:

[0227] If the other UPF network element receives multicast data sent by the root UPF network element, then the other UPF network element sends the multicast data to the gNB;

[0228] If the other UPF network element receives multicast data sent by the gNB directly connected to the other UPF network element, then the other UPF network element sends the multicast data to the root UPF network element;

[0229] If the other UPF network element receives unicast data sent by the gNB directly connected to the other UPF network element, then the other UPF network element sends the unicast data to the destination UPF network element or the gNB.

[0230] Specifically, in the embodiments of the present application, the multicast data forwarding rules of other UPF network elements within the multicast group include the following:

[0231] If other UPF network elements receive the multicast data sent by the root UPF network element, other UPF network elements refer to information such as the multicast group address and the UE ID List, and send the multicast data to the gNB through the established N3 tunnel;

[0232] If other UPF network elements receive the multicast data sent by the gNB directly connected to them, other UPF network elements refer to information such as the multicast group address and the UE ID List, and send the multicast data to the root UPF network element through the multicast tunnel;

[0233] If other UPF network elements receive the unicast data sent by the gNB directly connected to them, other UPF network elements send the unicast data to the destination UPF network element or the gNB through the unicast tunnel according to the unicast address.

[0234] In the embodiments of the present application, through the defined forwarding rules, other UPF network elements within the multicast group perform data forwarding according to the forwarding rules, effectively utilizing resources and saving signaling overhead and resource consumption.

[0235] Figure 6 It is the second flow schematic diagram of the point-to-multipoint data transmission method provided by the embodiments of the present application. As Figure 6 shown, the embodiments of the present application provide a point-to-multipoint data transmission method, and its execution subject can be the root UPF network element. The method includes:

[0236] Step 601, receiving a first N4 session establishment request message sent by a session management function SMF network element; the first N4 session establishment request message contains a first data forwarding rule.

[0237] Specifically, after the SMF network element determines the root UPF network element, it sends a first N4 session establishment request message to the root UPF network element.

[0238] The root UPF network element receives the first N4 session establishment request message sent by the SMF network element.

[0239] The first N4 session establishment request message contains a first data forwarding rule.

[0240] The first data forwarding rule is used to indicate the way for the root UPF network element to perform multicast data forwarding. The multicast data in the embodiments of the present application can be T2mT data in the space-air-ground integrated network.

[0241] Step 602, forwarding the multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network.

[0242] Specifically, after receiving the first N4 session establishment request message sent by the SMF network element, when there is multicast data to be transmitted, the root UPF network element forwards the multicast data according to the first data forwarding rule.

[0243] Figure 7 It is a data flow diagram of point-to-multipoint data transmission provided by an embodiment of the present application. As Figure 7 shown, the arrows in the figure indicate the data flow direction. As an example, when UE1 needs to send multicast data, UE1 first sends the multicast data to gNB1, then gNB1 forwards the multicast data to the UPF1 network element, and then the UPF1 network element forwards the multicast data to the root UPF network element. The root UPF network element forwards the multicast data according to the first data forwarding rule.

[0244] By receiving the data forwarding rule sent by the SMF network element, the embodiment of the present application enables the root UPF network element to perform data transmission with other UPFs within the multicast group respectively, without re-establishing the N9 tunnel between the UPF network elements, effectively utilizing resources and saving signaling overhead and resource consumption.

[0245] Optionally, forwarding the multicast data according to the first data forwarding rule includes:

[0246] Receiving the multicast data sent by the base station gNB directly connected to the root user plane function UPF network element;

[0247] Sending the multicast data to other UPF network elements within the multicast group.

[0248] Specifically, in the embodiment of the present application, the root UPF network element can receive the multicast data sent by the gNB directly connected to it.

[0249] If the root UPF network element receives the multicast data sent by the gNB directly connected to it, the root UPF network element sends the multicast data to other UPF network elements within the multicast group.

[0250] For example, Figure 7 in, UE5 has multicast data to be sent. UE5 sends the multicast data to gNB3. gNB3 is the gNB directly connected to the root UPF network element. After the root UPF network element receives the multicast data sent by gNB3, it sends the multicast data to other UPF network elements (UPF1 network element and UPF2 network element) within the multicast group.

[0251] In the embodiment of the present application, the root UPF network element further effectively utilizes resources, saves signaling overhead and resource consumption by receiving the multicast data sent by the gNB directly connected to it and then sending the multicast data to other UPF network elements within the multicast group.

[0252] Optionally, forwarding multicast data according to the first data forwarding rule includes:

[0253] Receiving multicast data sent by any UPF network element within the multicast group;

[0254] Sending the multicast data to other UPF network elements within the multicast group.

[0255] Specifically, in the embodiments of the present application, the root UPF network element can receive multicast data sent by any UPF network element within the multicast group.

[0256] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group.

[0257] For example, Figure 7 In, UE1 needs to send multicast data. UE1 first sends the multicast data to gNB1, then gNB1 forwards the multicast data to the UPF1 network element, and then the UPF1 network element forwards the multicast data to the root UPF network element. The root UPF network element receives the multicast data sent by the UPF1 network element within the multicast group, and then sends the multicast data to other UPF network elements (UPF1 network element and UPF2 network element) within the multicast group.

[0258] In the embodiments of the present application, the root UPF network element further effectively utilizes resources, saves signaling overhead and resource consumption by receiving multicast data sent by any UPF network element within the multicast group and then sending the multicast data to other UPF network elements within the multicast group.

[0259] Optionally, forwarding multicast data according to the first data forwarding rule includes:

[0260] Receiving multicast data sent by any UPF network element within the multicast group;

[0261] If the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, sending the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0262] Specifically, in the embodiments of the present application, the root UPF network element can receive multicast data sent by any UPF network element within the multicast group.

[0263] If the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0264] For example, Figure 7In this case, when UE1 needs to send multicast data, UE1 first sends the multicast data to gNB1, then gNB1 forwards the multicast data to the UPF1 network element, and then the UPF1 network element forwards the multicast data to the root UPF network element. The root UPF network element receives the multicast data sent by the UPF1 network element within the multicast group, and then sends the multicast data to other UPF network elements (UPF1 network element and UPF2 network element) within the multicast group. gNB3 is a gNB directly connected to the root UPF network element. UE5 accesses gNB3. If UE5 is in the UE list of the multicast group, the root UPF network element also needs to send the multicast data to gNB3 directly connected to it.

[0265] In the embodiment of the present application, the root UPF network element receives the multicast data sent by any UPF network element within the multicast group, and then sends the multicast data to other UPF network elements within the multicast group and the gNB directly connected to it, which further effectively utilizes resources and saves signaling overhead and resource consumption.

[0266] Figure 8 It is the third flowchart of the point-to-multipoint data transmission method provided by the embodiment of the present application. As Figure 8 shown, the embodiment of the present application provides a point-to-multipoint data transmission method, and its execution entity can be a UPF network element (non-root UPF network element). The method includes:

[0267] Step 801, receive a second N4 session establishment request message sent by a session management function SMF network element; the second N4 session establishment request message includes a second data forwarding rule; the second data forwarding rule is used to indicate the way of multicast data forwarding by other UPF network elements within the multicast group; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network.

[0268] Specifically, after determining the root UPF network element, the SMF network element sends a second N4 session establishment request message to the UPF network element.

[0269] The UPF network element receives the second N4 session establishment request message sent by the SMF network element.

[0270] The second N4 session establishment request message includes a second data forwarding rule.

[0271] The second data forwarding rule is used to indicate the way of multicast data forwarding by the UPF network element. The multicast data in the embodiment of the present application can be T2mT data in the space-air-ground integrated network.

[0272] Step 802, forward the multicast data according to the second data forwarding rule.

[0273] Specifically, after receiving the second N4 session establishment request message sent by the SMF network element, when there is multicast data to be transmitted, the UPF network element forwards the multicast data according to the second data forwarding rule.

[0274] As Figure 7 shown, UE1 needs to send multicast data. UE1 first sends the multicast data to gNB1, then gNB1 forwards the multicast data to the UPF1 network element, then the UPF1 network element forwards the multicast data to the root UPF network element, and the root UPF network element sends the multicast data to the UPF1 network element and the UPF2 network element according to the first data forwarding rule. After receiving the multicast data, the UPF1 network element and the UPF2 network element forward the multicast data according to the second data forwarding rule.

[0275] By receiving the data forwarding rule sent by the SMF network element in the embodiment of the present application, when the UPF network element receives multicast data, the UPF network element forwards the multicast data to the root UPF. The root UPF network element transmits data with other UPFs within the multicast group respectively, without re - establishing the N9 tunnel between UPF network elements, effectively utilizing resources and saving signaling overhead and resource consumption.

[0276] Optionally, the forwarding of the multicast data according to the second data forwarding rule includes:

[0277] Receiving the multicast data sent by the directly connected base station gNB;

[0278] Sending the multicast data to the root user plane function UPF network element.

[0279] Specifically, in the embodiment of the present application, the UPF network element can receive the multicast data sent by the gNB directly connected to it.

[0280] After the UPF network element receives the multicast data sent by the gNB directly connected to it, it sends the multicast data to the root UPF network element.

[0281] For example, Figure 7 in, UE1 needs to send multicast data. UE1 first sends the multicast data to gNB1. gNB1 is the gNB directly connected to the UPF1 network element. Then gNB1 forwards the multicast data to the UPF1 network element, and then the UPF1 network element forwards the multicast data to the root UPF network element.

[0282] By receiving the multicast data sent by the gNB directly connected to it in the embodiment of the present application, when the UPF network element receives multicast data, the UPF network element forwards the multicast data to the root UPF. The root UPF network element transmits data with other UPFs within the multicast group respectively, without re - establishing the N9 tunnel between UPF network elements, effectively utilizing resources and saving signaling overhead and resource consumption.

[0283] Optionally, forwarding the multicast data according to the second data forwarding rule includes:

[0284] Receiving the multicast data sent by the root UPF network element;

[0285] Sending the multicast data to the gNB.

[0286] Specifically, in the embodiment of the present application, the UPF network element can receive the multicast data sent by the root UPF network element.

[0287] After the UPF network element receives the multicast data sent by the root UPF network element, it sends the multicast data to the gNB.

[0288] For example, Figure 7 in, UE1 needs to send multicast data. UE1 first sends the multicast data to gNB1, then gNB1 forwards the multicast data to the UPF1 network element, then the UPF1 network element forwards the multicast data to the root UPF network element, and the root UPF network element receives the multicast data sent by the UPF1 network element within the multicast group, and then sends the multicast data to the UPF1 network element and the UPF2 network element within the multicast group. After the UPF1 network element receives the multicast data sent by the root UPF network element, it forwards the multicast data to the directly connected gNB1. After the UPF2 network element receives the multicast data sent by the root UPF network element, it forwards the multicast data to the directly connected gNB2.

[0289] In the embodiment of the present application, by receiving the multicast data sent by the root UPF network element, when the UPF network element receives the multicast data, it forwards the multicast data to the root UPF. The root UPF network element performs data transmission with other UPFs within the multicast group respectively, without re - establishing the N9 tunnel between UPF network elements, effectively utilizing resources and saving signaling overhead and resource consumption.

[0290] Figure 9 is the fourth flow diagram of the point - to - multi - point data transmission method provided by the embodiment of the present application. As Figure 9 shown, the embodiment of the present application provides a point - to - multi - point data transmission method, and its execution subject can be the gNB. The method includes:

[0291] Step 901, receiving the multicast data sent by the user plane function UPF network element; the multicast data is the point - to - multi - point T2mT data in the space - air - ground integrated network.

[0292] Specifically, in the embodiment of the present application, whether it is the root UPF network element or other UPF network elements within the multicast group, after receiving the multicast data, if the UE within its coverage area is in the UE list within the multicast group, it is required to forward the multicast data to the directly connected gNB.

[0293] In the embodiment of the present application, the multicast data is the point-to-multipoint T2mT data in the air-ground integrated network.

[0294] The gNB receives the multicast data sent by the UPF network element.

[0295] Step 902: If it is determined that the radio bearer of the unicast session existing between the gNB and the terminal UE meets the quality of service QoS of the multicast session, then multiplex the radio bearer of the unicast session and send the multicast data to the UE.

[0296] Specifically, in the embodiment of the present application, after the gNB receives the multicast data sent by the UPF network element, it determines whether an RB of a unicast session has been established between the gNB and the UE.

[0297] If an RB of a unicast session has been established between the gNB and the UE, it is further determined whether the RB of the unicast session can meet the QoS of the multicast session.

[0298] If the RB of the unicast session established between the gNB and the UE can meet the QoS of the multicast session, the gNB multiplexes the RB of the unicast session and sends the multicast data to the UE.

[0299] For example, Figure 7 in, UE1 needs to send multicast data. UE1 first sends the multicast data to gNB1, then gNB1 forwards the multicast data to the UPF1 network element, then the UPF1 network element forwards the multicast data to the root UPF network element. The root UPF network element receives the multicast data sent by the UPF1 network element within the multicast group, and then sends the multicast data to the UPF1 network element and the UPF2 network element within the multicast group. After the UPF1 network element receives the multicast data sent by the root UPF network element, it forwards the multicast data to the directly connected gNB1. After the UPF2 network element receives the multicast data sent by the root UPF network element, it forwards the multicast data to the directly connected gNB2.

[0300] If gNB2 determines that the RB of the unicast session established between it and UE3 can meet the QoS of the multicast session, then gNB2 multiplexes the RB of the unicast session and sends the multicast data to UE3.

[0301] In the embodiment of the present application, by multiplexing the already established RB of the unicast session, the repeated establishment of the RB is avoided, the resources are effectively utilized, and the signaling overhead and resource consumption are saved.

[0302] Optionally, after receiving the multicast data sent by the user plane function UPF network element, it further includes:

[0303] If it is determined that there is no radio bearer for the unicast session with the UE, or the radio bearer of the unicast session existing with the UE does not meet the QoS of the multicast session, a radio bearer with the UE is established, and the multicast data is sent to the UE.

[0304] Specifically, in the embodiment of the present application, if it is determined that there is no radio bearer for the unicast session with the UE, or the radio bearer of the unicast session existing with the UE does not meet the QoS of the multicast session, the gNB establishes a radio bearer with the UE and sends the multicast data to the UE.

[0305] For example, Figure 7 In, UE1 needs to send multicast data. UE1 first sends the multicast data to gNB1, then gNB1 forwards the multicast data to the UPF1 network element, then the UPF1 network element forwards the multicast data to the root UPF network element. The root UPF network element receives the multicast data sent by the UPF1 network element within the multicast group, and then sends the multicast data to the UPF1 network element and the UPF2 network element within the multicast group. After receiving the multicast data sent by the root UPF network element, the UPF1 network element forwards the multicast data to the directly connected gNB1. After receiving the multicast data sent by the root UPF network element, the UPF2 network element forwards the multicast data to the directly connected gNB2.

[0306] If gNB2 determines that the RB of the unicast session already established between it and UE4 cannot meet the QoS of the multicast session, then gNB2 re - establishes the RB of the unicast session with UE4, and sends the multicast data to UE4 through the newly established RB of the unicast session.

[0307] In the embodiment of the present application, by determining that there is no RB for the unicast session with the UE, or the RB of the unicast session existing with the UE does not meet the QoS of the multicast session, a new RB is re - established only then, which avoids repeated establishment of RBs, effectively utilizes resources, and saves signaling overhead and resource consumption.

[0308] Optionally, the UPF network element is the root UPF network element.

[0309] Specifically, in the embodiment of the present application, the gNB receives the multicast data sent by the root UPF network element. The multicast data is the point - to - multi - point T2mT data in the space - air - ground integrated network. The function and role of the root UPF network element are the same as those of the root UPF network element in the above - mentioned embodiment, and will not be elaborated here.

[0310] If the gNB determines that the radio bearer of the unicast session existing between it and the UE meets the QoS of the multicast session, it multiplexes the radio bearer of the unicast session and sends the multicast data to the UE.

[0311] In the embodiments of the present application, by reusing the RBs of an established unicast session, the repeated establishment of RBs is avoided, effectively utilizing resources and saving signaling overhead and resource consumption.

[0312] Figure 10 It is a schematic structural diagram of an SMF network element provided by the embodiments of the present application. As Figure 10 shown, the SMF network element includes a memory 1020, a transceiver 1000, and a processor 1010:

[0313] The memory 1020 is used to store computer programs; the transceiver 1000 is used to transmit and receive data under the control of the processor 1010; the processor 1010 is used to read the computer programs in the memory 1020 and perform the following operations:

[0314] Determine the root user plane function UPF network element; send a first N4 session establishment request message to the root UPF network element; the first N4 session establishment request message includes a first data forwarding rule; the first data forwarding rule is used to indicate the way for the root UPF network element to forward multicast data; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network.

[0315] Specifically, the transceiver 1000 is used to receive and transmit data under the control of the processor 1010.

[0316] Among them, in Figure 10 the bus architecture may include any number of interconnected buses and bridges, specifically, various circuits represented by one or more processors represented by the processor 1010 and the memory represented by the memory 1020 are linked together. The bus architecture can also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art. Therefore, they will not be further described herein. The bus interface provides an interface. The transceiver 1000 can be multiple elements, that is, including a transmitter and a receiver, providing a unit for communicating with various other devices on a transmission medium, and these transmission media include wireless channels, wired channels, optical cables, etc. For different user devices, the user interface 1030 can also be an interface capable of externally connecting and internally connecting required devices, and the connected devices include but are not limited to keypads, displays, speakers, microphones, joysticks, etc.

[0317] The processor 1010 is responsible for managing the bus architecture and general processing, and the memory 1020 can store the data used by the processor 1010 when performing operations.

[0318] Optionally, the processor 1010 may be a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a CPLD (Complex Programmable Logic Device). The processor may also adopt a multi-core architecture.

[0319] The processor is used to execute any of the methods provided in the embodiments of the present application according to the obtained executable instructions by calling the computer program stored in the memory. The processor and the memory may also be physically separated.

[0320] Optionally, determining the root user plane function UPF network element includes:

[0321] Regarding the UPF network element directly connected to all UPF network elements in the multicast group as the root UPF network element.

[0322] Optionally, determining the root user plane function UPF network element includes:

[0323] Regarding the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group as the root UPF network element.

[0324] Optionally, determining the root user plane function UPF network element includes:

[0325] Regarding the UPF network element with the least user plane traffic as the root UPF network element.

[0326] Optionally, the first data forwarding rule includes:

[0327] If the root UPF network element receives multicast data sent by the gNB directly connected to the root UPF network element, the root UPF network element sends the multicast data to other UPF network elements within the multicast group;

[0328] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group;

[0329] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, and the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0330] Optionally, after determining the root user plane function (UPF) network element, the method further includes:

[0331] Sending a second N4 session establishment request message to other UPF network elements within the multicast group; the second N4 session establishment request message includes a second data forwarding rule; the second data forwarding rule is used to indicate the manner in which other UPF network elements within the multicast group forward multicast data.

[0332] Optionally, the second data forwarding rule includes:

[0333] If the other UPF network element receives multicast data sent by the root UPF network element, the other UPF network element sends the multicast data to the gNB;

[0334] If the other UPF network element receives multicast data sent by a gNB directly connected to the other UPF network element, the other UPF network element sends the multicast data to the root UPF network element;

[0335] If the other UPF network element receives unicast data sent by a gNB directly connected to the other UPF network element, the other UPF network element sends the unicast data to the destination UPF network element or the gNB.

[0336] It should be noted here that the above-mentioned SMF network element provided in the embodiments of the present application can implement all the method steps of the method embodiments with the SMF network element as the execution subject, and can achieve the same technical effects. The same parts and beneficial effects as those in the method embodiments will not be specifically described in this embodiment.

[0337] Figure 11 is a schematic structural diagram of a root UPF network element provided in the embodiments of the present application. As Figure 11 shown, the root UPF network element includes a memory 1120, a transceiver 1100, and a processor 1110:

[0338] The memory 1120 is used to store computer programs; the transceiver 1100 is used to transmit and receive data under the control of the processor 1110; the processor 1110 is used to read the computer programs in the memory 1120 and perform the following operations:

[0339] Receiving a first N4 session establishment request message sent by a session management function (SMF) network element; the first N4 session establishment request message includes a first data forwarding rule;

[0340] Forwarding multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in the air-ground integrated network.

[0341] Specifically, the transceiver 1100 is used to receive and send data under the control of the processor 1110.

[0342] Among them, in Figure 11 The bus architecture can include any number of interconnected buses and bridges, specifically linking together various circuits of one or more processors represented by the processor 1110 and the memory represented by the memory 1120. The bus architecture can also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be further described herein. The bus interface provides an interface. The transceiver 1100 can be multiple components, that is, including a transmitter and a receiver, providing a unit for communicating with various other devices on the transmission medium, and these transmission media include wireless channels, wired channels, optical fiber cables, and other transmission media. The processor 1110 is responsible for managing the bus architecture and general processing, and the memory 1120 can store the data used by the processor 1110 when executing operations.

[0343] The processor 1110 can be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD), and the processor can also adopt a multi-core architecture.

[0344] Optionally, forwarding the multicast data according to the first data forwarding rule includes:

[0345] Receiving the multicast data sent by the base station gNB directly connected to the root user plane function UPF network element;

[0346] Sending the multicast data to other UPF network elements within the multicast group.

[0347] Optionally, forwarding the multicast data according to the first data forwarding rule includes:

[0348] Receiving the multicast data sent by any UPF network element within the multicast group;

[0349] Sending the multicast data to other UPF network elements within the multicast group.

[0350] Optionally, forwarding the multicast data according to the first data forwarding rule includes:

[0351] Receiving the multicast data sent by any UPF network element within the multicast group;

[0352] If the UE under the gNB directly connected to the root UPF network element is in the in-group UE list of the multicast group, the multicast data is sent to other UPF network elements in the multicast group and the gNB directly connected to the root UPF network element.

[0353] Here it should be noted that the above-mentioned root UPF network element provided by the embodiments of the present application can implement all the method steps implemented by the method embodiments with the root UPF network element as the execution subject, and can achieve the same technical effects. The same parts and beneficial effects as those in the method embodiments will not be specifically described herein.

[0354] Figure 12 is a schematic structural diagram of a UPF network element provided by the embodiments of the present application, as Figure 12 shown, the UPF network element includes a memory 1220, a transceiver 1200, and a processor 1210:

[0355] The memory 1220 is used to store computer programs; the transceiver 1200 is used to receive and send data under the control of the processor 1210; the processor 1210 is used to read the computer programs in the memory 1220 and perform the following operations:

[0356] Receive a second N4 session establishment request message sent by a session management function SMF network element; the second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the way for other UPF network elements in the multicast group to forward multicast data; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network;

[0357] Forward the multicast data according to the second data forwarding rule.

[0358] Specifically, the transceiver 1200 is used to receive and send data under the control of the processor 1210.

[0359] Among them, in Figure 12 the bus architecture may include any number of interconnected buses and bridges, specifically various circuits of one or more processors represented by the processor 1210 and the memory represented by the memory 1220 are linked together. The bus architecture can also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art, so they will not be further described herein. The bus interface provides an interface. The transceiver 1200 can be multiple elements, that is, including a transmitter and a receiver, and provides a unit for communicating with various other devices on a transmission medium, which includes transmission media such as wireless channels, wired channels, and optical cables. The processor 1210 is responsible for managing the bus architecture and general processing, and the memory 1220 can store the data used by the processor 1210 when performing operations.

[0360] The processor 1210 can be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD). The processor can also adopt a multi-core architecture.

[0361] Optionally, forwarding the multicast data according to the second data forwarding rule includes:

[0362] Receiving multicast data sent by a directly connected base station gNB;

[0363] Sending the multicast data to the root user plane function UPF network element.

[0364] Optionally, forwarding the multicast data according to the second data forwarding rule includes:

[0365] Receiving multicast data sent by the root UPF network element;

[0366] Sending the multicast data to the gNB.

[0367] It should be noted here that the above UPF network element provided in the embodiment of the present application can implement all the method steps implemented by the method embodiment with the UPF network element as the execution subject, and can achieve the same technical effects. The same parts and beneficial effects as those in the method embodiment will not be specifically described in this embodiment.

[0368] Figure 13 is a schematic structural diagram of a base station provided in the embodiment of the present application. As Figure 13 shown, the base station includes a memory 1320, a transceiver 1300, and a processor 1310:

[0369] The memory 1320 is used to store computer programs; the transceiver 1300 is used to transmit and receive data under the control of the processor 1310; the processor 1310 is used to read the computer programs in the memory 1320 and perform the following operations:

[0370] Receiving multicast data sent by a user plane function UPF network element; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network;

[0371] If it is determined that the radio bearer of the unicast session existing with the terminal UE meets the quality of service QoS of the multicast session, multiplex the radio bearer of the unicast session and send the multicast data to the UE.

[0372] Specifically, the transceiver 1300 is used to receive and send data under the control of the processor 1310.

[0373] Among them, in Figure 13 The bus architecture may include any number of interconnected buses and bridges, specifically, various circuits represented by one or more processors represented by the processor 1310 and the memory represented by the memory 1320 are linked together. The bus architecture can also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be further described herein. The bus interface provides an interface. The transceiver 1300 may be multiple components, that is, including a transmitter and a receiver, and provides a unit for communicating with various other devices on a transmission medium, and these transmission media include wireless channels, wired channels, optical fiber cables, and other transmission media. The processor 1310 is responsible for managing the bus architecture and general processing, and the memory 1320 may store data used by the processor 1310 when executing operations.

[0374] The processor 1310 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD), and the processor may also adopt a multi-core architecture.

[0375] Optionally, after receiving the multicast data sent by the user plane function UPF network element, it further includes:

[0376] If it is determined that there is no radio bearer for the unicast session with the UE, or the radio bearer for the unicast session existing with the UE does not meet the QoS of the multicast session, then establish a radio bearer with the UE and send the multicast data to the UE.

[0377] Optionally, the UPF network element is a root UPF network element

[0378] It should be noted here that the above base station provided by the embodiments of the present application can implement all the method steps implemented by the method embodiments with the base station as the execution subject, and can achieve the same technical effects, and the same parts and beneficial effects as the method embodiments in this embodiment will not be specifically described herein.

[0379] Figure 14 It is one of the flow schematic diagrams of the point-to-multipoint data transmission device provided by the embodiments of the present application, as Figure 14As shown, the point-to-multipoint data transmission device includes a determination module 1401 and a first transmission module 1402, where:

[0380] The determination module 1401 is used to determine the root user plane function UPF network element; the first transmission module 1402 is used to send a first N4 session establishment request message to the root UPF network element; the first N4 session establishment request message contains a first data forwarding rule; the first data forwarding rule is used to indicate the method for the root UPF network element to perform multicast data forwarding; the multicast data is the point-to-multipoint T2mT data in the space-air-ground integrated network.

[0381] Optionally, determining the root user plane function UPF network element includes:

[0382] Regarding the UPF network element directly connected to all UPF network elements in the multicast group as the root UPF network element.

[0383] Optionally, determining the root user plane function UPF network element includes:

[0384] Regarding the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group as the root UPF network element.

[0385] Optionally, determining the root user plane function UPF network element includes:

[0386] Regarding the UPF network element with the least user plane traffic as the root UPF network element.

[0387] Optionally, the first data forwarding rule includes:

[0388] If the root UPF network element receives multicast data sent by the gNB directly connected to the root UPF network element, the root UPF network element will send the multicast data to other UPF network elements within the multicast group;

[0389] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, the root UPF network element will send the multicast data to other UPF network elements within the multicast group;

[0390] If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, and the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, the root UPF network element will send the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0391] Optionally, after determining the root user plane function UPF network element, it further includes:

[0392] Send a second N4 session establishment request message to other UPF network elements within the multicast group; the second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the method for other UPF network elements within the multicast group to forward multicast data.

[0393] Optionally, the second data forwarding rule includes:

[0394] If the other UPF network element receives the multicast data sent by the root UPF network element, the other UPF network element sends the multicast data to the gNB;

[0395] If the other UPF network element receives the multicast data sent by the gNB directly connected to the other UPF network element, the other UPF network element sends the multicast data to the root UPF network element;

[0396] If the other UPF network element receives the unicast data sent by the gNB directly connected to the other UPF network element, the other UPF network element sends the unicast data to the destination UPF network element or the gNB.

[0397] Figure 15 It is the second schematic diagram of the process of the point-to-multipoint data transmission device provided by the embodiments of the present application. As Figure 15 shown, the point-to-multipoint data transmission device includes a first receiving module 1501 and a second sending module 1502, where:

[0398] The first receiving module 1501 is used to receive a first N4 session establishment request message sent by a session management function SMF network element; the first N4 session establishment request message contains a first data forwarding rule; the second sending module 1502 is used to forward multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network.

[0399] Optionally, the forwarding of multicast data according to the first data forwarding rule includes:

[0400] Receive multicast data sent by a base station gNB directly connected to a root user plane function UPF network element;

[0401] Send the multicast data to other UPF network elements within the multicast group.

[0402] Optionally, the forwarding of multicast data according to the first data forwarding rule includes:

[0403] Receive multicast data sent by any UPF network element within the multicast group;

[0404] Send the multicast data to other UPF network elements within the multicast group.

[0405] Optionally, forwarding multicast data according to the first data forwarding rule includes:

[0406] Receiving multicast data sent by any UPF network element within the multicast group;

[0407] If the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, sending the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

[0408] Figure 16 It is the third flow schematic diagram of the point-to-multipoint data transmission device provided by the embodiments of the present application. As Figure 16 shown, the point-to-multipoint data transmission device includes a second receiving module 1601 and a third sending module 1602, where:

[0409] The second receiving module 1601 is configured to receive a second N4 session establishment request message sent by a session management function SMF network element; the second N4 session establishment request message includes a second data forwarding rule; the second data forwarding rule is used to indicate the way for other UPF network elements within the multicast group to forward multicast data; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; the third sending module 1602 is configured to forward the multicast data according to the second data forwarding rule.

[0410] Optionally, forwarding multicast data according to the second data forwarding rule includes:

[0411] Receiving multicast data sent by a directly connected base station gNB;

[0412] Sending the multicast data to the root user plane function UPF network element.

[0413] Optionally, forwarding multicast data according to the second data forwarding rule includes:

[0414] Receiving multicast data sent by the root UPF network element;

[0415] Sending the multicast data to the gNB.

[0416] Figure 17 It is the fourth flow schematic diagram of the point-to-multipoint data transmission device provided by the embodiments of the present application. As Figure 17 shown, the point-to-multipoint data transmission device includes a third receiving module 1701 and a fourth sending module 1702, where:

[0417] The third receiving module 1701 is used to receive multicast data sent by a User Plane Function (UPF) network element; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; the fourth sending module 1702 is used to multiplex the radio bearer of the unicast session and send the multicast data to the UE if it is determined that the radio bearer of the unicast session existing between the module and the terminal UE meets the Quality of Service (QoS) of the multicast session.

[0418] Optionally, after receiving the multicast data sent by the UPF network element, it further includes:

[0419] If it is determined that there is no radio bearer of the unicast session between the module and the UE, or the radio bearer of the unicast session existing between the module and the UE does not meet the QoS of the multicast session, a radio bearer with the UE is established and the multicast data is sent to the UE.

[0420] Optionally, the UPF network element is a root UPF network element

[0421] It should be noted that the division of units / modules in the above embodiments of the present application is schematic, only a logical function division, and there may be other division methods in actual implementation. In addition, in each embodiment of the present application, each functional unit may be integrated in a processing unit, or each unit may exist physically alone, or two or more units may be integrated in one unit. The above integrated unit may be implemented in the form of hardware or in the form of a software functional unit.

[0422] If the above integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: various media such as a USB flash drive, a mobile hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disc that can store program codes.

[0423] The embodiments of the present application further provide a processor-readable storage medium. The processor-readable storage medium stores a computer program, and the computer program is used to cause the processor to execute the methods provided in the above embodiments, including:

[0424] Determine the root user plane function UPF network element; send a first N4 session establishment request message to the root UPF network element; the first N4 session establishment request message contains a first data forwarding rule; the first data forwarding rule is used to indicate the multicast data forwarding method of the root UPF network element; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network.

[0425] Or it includes:

[0426] Receive a first N4 session establishment request message sent by the session management function SMF network element; the first N4 session establishment request message contains a first data forwarding rule; forward the multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network.

[0427] Or it includes:

[0428] Receive a second N4 session establishment request message sent by the session management function SMF network element; the second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the multicast data forwarding method of other UPF network elements within the multicast group; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; forward the multicast data according to the second data forwarding rule.

[0429] Or it includes:

[0430] Receive multicast data sent by the user plane function UPF network element; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; if it is determined that the radio bearer of the unicast session existing with the terminal UE meets the quality of service QoS of the multicast session, then multiplex the radio bearer of the unicast session and send the multicast data to the UE.

[0431] It should be noted that: the processor-readable storage medium can be any available medium or data storage device that the processor can access, including but not limited to magnetic memory (such as floppy disks, hard disks, magnetic tapes, magneto-optical discs (MO), etc.), optical memory (such as CDs, DVDs, BDs, HVDs, etc.), and semiconductor memory (such as ROM, EPROM, EEPROM, non-volatile memory (NAND FLASH), solid state drives (SSD)), etc.

[0432] In addition, it should be noted that: the term "and / or" in the embodiments of the present application describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0433] In the embodiments of the present application, the term "plurality" refers to two or more, and other quantifiers are similar thereto.

[0434] The technical solutions provided by the embodiments of the present application can be applied to a variety of systems, especially 5G systems. For example, the applicable systems can be a global system of mobile communication (GSM) system, a code division multiple access (CDMA) system, a wideband code division multiple access (WCDMA) general packet radio service (GPRS) system, a long term evolution (LTE) system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD) system, a long term evolution advanced (LTE-A) system, a universal mobile telecommunication system (UMTS), a worldwide interoperability for microwave access (WiMAX) system, a 5G new radio (NR) system, etc. Both terminal devices and network devices are included in these various systems. The core network part can also be included in the system, such as an evolved packet system (EPS), a 5G system (5GS), etc.

[0435] The terminal device involved in the embodiments of the present application can be a device that provides voice and / or data connectivity to users, such as a handheld device with wireless connection capabilities, or other processing devices connected to a wireless modem, etc. In different systems, the name of the terminal device may also be different. For example, in a 5G system, the terminal device can be called a user equipment (UE). The wireless terminal device can communicate with one or more core networks (CNs) via a radio access network (RAN). The wireless terminal device can be a mobile terminal device, such as a mobile phone (or a "cellular" phone) and a computer with a mobile terminal device. For example, it can be a portable, pocket-sized, handheld, computer-integrated, or vehicle-mounted mobile device, which exchanges language and / or data with the radio access network. For example, devices such as personal communication service (PCS) phones, cordless phones, session initiated protocol (SIP) phones, wireless local loop (WLL) stations, and personal digital assistants (PDAs). The wireless terminal device can also be referred to as a system, a subscriber unit, a subscriber station, a mobile station, a mobile, a remote station, an access point, a remote terminal device, an access terminal device, a user terminal device, a user agent, or a user device, which is not limited in the embodiments of the present application.

[0436] The network device involved in the embodiments of this application can be a base station, which can include multiple cells that provide services to terminals. Depending on specific application scenarios, the base station can also be referred to as an access point, or it can be a device in the access network that communicates with wireless terminal devices through one or more sectors over the air interface, or other names. The network device can be used to mutually replace the received airframes and Internet Protocol (IP) packets, and act as a router between the wireless terminal device and the rest of the access network, where the rest of the access network can include an Internet Protocol (IP) communication network. The network device can also coordinate the management of the attributes of the air interface. For example, the network device involved in the embodiments of this application can be a network device (Base Transceiver Station, BTS) in the Global System for Mobile communications (GSM) or Code Division Multiple Access (CDMA), or it can be a network device (NodeB) in Wide-band Code Division Multiple Access (WCDMA), or it can also be an evolved network device (evolutional Node B, eNB or e-NodeB) in the Long Term Evolution (LTE) system, a 5G base station (gNB) in the 5G network architecture (next generation system), or it can be a Home evolved Node B (HeNB), a relay node, a femto, a pico, etc. The embodiments of this application do not limit this. In some network architectures, the network device can include a centralized unit (centralized unit, CU) node and a distributed unit (distributed unit, DU) node, and the centralized unit and the distributed unit can also be arranged separately geographically.

[0437] A network device and a terminal device can each use one or more antennas for Multi-Input Multi-Output (MIMO) transmission. The MIMO transmission can be Single User MIMO (SU-MIMO) or Multiple User MIMO (MU-MIMO). According to the form and quantity of the root antenna combination, the MIMO transmission can be 2D-MIMO, 3D-MIMO, FD-MIMO, or massive-MIMO, or it can also be diversity transmission, precoding transmission, beamforming transmission, etc.

[0438] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0439] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer-executable instructions. These computer-executable instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0440] These processor-executable instructions can also be stored in a processor-readable memory that can guide a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the processor-readable memory generate a manufactured product including an instruction device, and the instruction device implements the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0441] These processor-executable instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Therefore, the instructions executed on the computer or other programmable device provide for implementing the functions in Figure 1One or more processes and / or boxes Figure 1 Steps of functions specified in one or more boxes

[0442] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these changes and modifications within it.

Claims

1. A point-to-multipoint data transmission method, characterized in that, including: Determine the root user plane function UPF network element, where the root UPF network element is used to receive multicast data and forward the multicast data to the UPF network elements within the multicast group; Send a first N4 session establishment request message to the root UPF network element; The first N4 session establishment request message contains a first data forwarding rule; the first data forwarding rule is used to indicate the way for the root UPF network element to forward multicast data; The multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; The determining the root user plane function UPF network element includes: Taking the UPF network element directly connected to all UPF network elements in the multicast group as the root UPF network element; or, Taking the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group as the root UPF network element; or, Taking the UPF network element with the least user plane traffic as the root UPF network element.

2. The point-to-multipoint data transmission method according to claim 1, wherein The first data forwarding rule includes: If the root UPF network element receives multicast data sent by the gNB directly connected to the root UPF network element, the root UPF network element sends the multicast data to other UPF network elements within the multicast group; If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group; If the root UPF network element receives multicast data sent by any UPF network element within the multicast group, and the UEs under the gNB directly connected to the root UPF network element are in the UE list within the multicast group, the root UPF network element sends the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

3. The point-to-multipoint data transmission method according to claim 1, characterized in that After determining the root user plane function UPF network element, it further includes: Sending a second N4 session establishment request message to other UPF network elements within the multicast group; the second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the way for other UPF network elements within the multicast group to forward multicast data.

4. The point-to-multipoint data transmission method according to claim 3, wherein The second data forwarding rule includes: If the other UPF network element receives multicast data sent by the root UPF network element, the other UPF network element sends the multicast data to the gNB; If the other UPF network element receives multicast data sent by the gNB directly connected to the other UPF network element, the other UPF network element sends the multicast data to the root UPF network element; If the other UPF network element receives unicast data sent by the gNB directly connected to the other UPF network element, the other UPF network element sends the unicast data to the destination UPF network element or the gNB.

5. A point-to-multipoint data transmission method, characterized in that, including: The root user plane function UPF network element receives a first N4 session establishment request message sent by the session management function SMF network element; The first N4 session establishment request message contains a first data forwarding rule, and the root UPF network element is used to receive multicast data and forward the multicast data to the UPF network elements within the multicast group; Forward multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; The root UPF network element is a UPF network element directly connected to all UPF network elements in the multicast group; or, the root UPF network element is the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group; or, the root UPF network element is the UPF network element with the least user plane traffic.

6. The point-to-multipoint data transmission method according to claim 5, wherein The forwarding of multicast data according to the first data forwarding rule includes: Receive multicast data sent by a base station gNB directly connected to the root user plane function UPF network element; Send the multicast data to other UPF network elements within the multicast group.

7. The point-to-multipoint data transmission method according to claim 5, wherein The forwarding of multicast data according to the first data forwarding rule includes: Receive multicast data sent by any UPF network element within the multicast group; Send the multicast data to other UPF network elements within the multicast group.

8. The point-to-multipoint data transmission method according to claim 5, wherein The forwarding of multicast data according to the first data forwarding rule includes: Receive multicast data sent by any UPF network element within the multicast group; If the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, send the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

9. A point-to-multipoint data transmission method, characterized in that, Includes: Receive a second N4 session establishment request message sent by the session management function SMF network element; The second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the method of multicast data forwarding by other UPF network elements within the multicast group; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; Forward multicast data according to the second data forwarding rule; Among them, the forwarding of multicast data according to the second data forwarding rule includes: Receive multicast data sent by the directly connected base station gNB; send the multicast data to the root user plane function UPF network element; or, Receive multicast data sent by the root UPF network element; send the multicast data to the gNB; Among them, the root UPF network element is used to receive multicast data and forward the multicast data to UPF network elements within the multicast group; The root UPF network element is a UPF network element directly connected to all UPF network elements in the multicast group; or, the root UPF network element is the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group; or, the root UPF network element is the UPF network element with the least user plane traffic.

10. A point-to-multipoint data transmission method, characterized in that, Includes: Receive multicast data sent by the root user plane function UPF network element; The multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network, and the root UPF network element is used to receive multicast data and forward the multicast data to UPF network elements within the multicast group; If it is determined that the radio bearer of the unicast session existing with the terminal UE meets the quality of service QoS of the multicast session, multiplex the radio bearer of the unicast session and send the multicast data to the UE; The root UPF network element is a UPF network element directly connected to all UPF network elements in the multicast group; or, the root UPF network element is the UPF network element with the largest number of terminal UEs among the directly connected base stations gNBs in the multicast group; or, the root UPF network element is the UPF network element with the least user plane traffic.

11. The point-to-multipoint data transmission method according to claim 10, wherein After receiving the multicast data sent by the receiving root user plane function UPF network element, it further includes: If it is determined that there is no radio bearer for the unicast session with the UE, or the radio bearer for the unicast session existing with the UE does not meet the QoS of the multicast session, a radio bearer with the UE is established, and the multicast data is sent to the UE.

12. A session management function SMF network element, characterized in that, It includes a memory, a transceiver, and a processor; The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; The processor is used to read the computer programs in the memory and perform the following operations: Determine the root user plane function UPF network element, where the root UPF network element is used to receive multicast data and forward the multicast data to the UPF network elements in the multicast group; Send a first N4 session establishment request message to the root UPF network element; The first N4 session establishment request message contains a first data forwarding rule; the first data forwarding rule is used to indicate the way for the root UPF network element to forward multicast data; The multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; The determining the root user plane function UPF network element includes: Regarding the UPF network element directly connected to all UPF network elements in the multicast group as the root UPF network element; or, Regarding the UPF network element with the largest number of terminal UEs among the directly connected base stations gNBs in the multicast group as the root UPF network element; or, Regarding the UPF network element with the least user plane traffic as the root UPF network element.

13. The SMF network element according to claim 12, characterized in that, The first data forwarding rule includes: If the root UPF network element receives multicast data sent by the gNB directly connected to the root UPF network element, the root UPF network element sends the multicast data to other UPF network elements in the multicast group; If the root UPF network element receives multicast data sent by any UPF network element in the multicast group, the root UPF network element sends the multicast data to other UPF network elements in the multicast group; If the root UPF network element receives multicast data sent by any UPF network element in the multicast group, and the UE under the gNB directly connected to the root UPF network element is in the UE list in the multicast group, the root UPF network element sends the multicast data to other UPF network elements in the multicast group and the gNB directly connected to the root UPF network element.

14. The SMF network element according to claim 12, characterized in that, After determining the root user plane function UPF network element, it further includes: Send a second N4 session establishment request message to other UPF network elements in the multicast group; the second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the way for other UPF network elements in the multicast group to forward multicast data.

15. The SMF network element according to claim 14, wherein The second data forwarding rule includes: If the other UPF network element receives the multicast data sent by the root UPF network element, the other UPF network element sends the multicast data to the gNB; If the other UPF network element receives the multicast data sent by the gNB directly connected to the other UPF network element, the other UPF network element sends the multicast data to the root UPF network element; If the other UPF network element receives the unicast data sent by the gNB directly connected to the other UPF network element, the other UPF network element sends the unicast data to the destination UPF network element or the gNB.

16. A root user plane function (UPF) network element, characterized in that, It includes a memory, a transceiver, and a processor; The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations: Receive a first N4 session establishment request message sent by a session management function SMF network element; the first N4 session establishment request message contains a first data forwarding rule; Forward multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; Among them, the root UPF network element is used to receive multicast data and forward the multicast data to the UPF network elements within the multicast group; The root UPF network element is a UPF network element directly connected to all UPF network elements in the multicast group; or, the root UPF network element is the UPF network element with the largest number of terminal UEs among the gNBs directly connected within the multicast group; or, the root UPF network element is the UPF network element with the least user plane traffic.

17. The root UPF network element according to claim 16, characterized in that, The forwarding of the multicast data according to the first data forwarding rule includes: Receive multicast data sent by a base station gNB directly connected to the root user plane function UPF network element; Send the multicast data to other UPF network elements within the multicast group.

18. The root UPF network element according to claim 16, characterized in that, The forwarding of the multicast data according to the first data forwarding rule includes: Receive multicast data sent by any UPF network element within the multicast group; Send the multicast data to other UPF network elements within the multicast group.

19. The root UPF network element according to claim 16, characterized in that, The forwarding of the multicast data according to the first data forwarding rule includes: Receive multicast data sent by any UPF network element within the multicast group; If the UE under the gNB directly connected to the root UPF network element is in the UE list within the multicast group, send the multicast data to other UPF network elements within the multicast group and the gNB directly connected to the root UPF network element.

20. A user plane function (UPF) network element, characterized in that, It includes a memory, a transceiver, and a processor; The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations: Receive a second N4 session establishment request message sent by a session management function SMF network element; the second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the way for other UPF network elements within the multicast group to forward multicast data; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; Forward multicast data according to the second data forwarding rule; Among them, forwarding the multicast data according to the second data forwarding rule includes: Receiving the multicast data sent by the directly connected base station gNB; sending the multicast data to the root user plane function UPF network element; or, Receiving the multicast data sent by the root UPF network element; sending the multicast data to the gNB; Among them, the root UPF network element is used to receive the multicast data and forward the multicast data to the UPF network elements within the multicast group; The root UPF network element is a UPF network element directly connected to all UPF network elements in the multicast group; or, the root UPF network element is the UPF network element with the largest number of terminal UEs among the UPF network elements directly connected to the base station gNB within the multicast group; or, the root UPF network element is the UPF network element with the least user plane traffic.

21. A base station, characterized in that, Including a memory, a transceiver, and a processor; The memory is used to store computer programs; The transceiver is used to send and receive data under the control of the processor; The processor is used to read the computer program in the memory and perform the following operations: Receiving the multicast data sent by the root user plane function UPF network element; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network, and the root UPF network element is used to receive the multicast data and forward the multicast data to the UPF network elements within the multicast group; If it is determined that the radio bearer of the unicast session existing with the terminal UE meets the quality of service QoS of the multicast session, multiplex the radio bearer of the unicast session and send the multicast data to the UE; The root UPF network element is a UPF network element directly connected to all UPF network elements in the multicast group; or, the root UPF network element is the UPF network element with the largest number of terminal UEs among the UPF network elements directly connected to the base station gNB within the multicast group; or, the root UPF network element is the UPF network element with the least user plane traffic.

22. The base station according to claim 21, wherein After receiving the multicast data sent by the root user plane function UPF network element, it further includes: If it is determined that there is no radio bearer of the unicast session with the UE, or the radio bearer of the unicast session existing with the UE does not meet the QoS of the multicast session, establish a radio bearer with the UE and send the multicast data to the UE.

23. A point-to-multipoint data transmission device, characterized in that, Including: A determination module, used to determine the root user plane function UPF network element, and the root UPF network element is used to receive the multicast data and forward the multicast data to the UPF network elements within the multicast group; A first sending module, used to send a first N4 session establishment request message to the root UPF network element; The first N4 session establishment request message includes a first data forwarding rule; the first data forwarding rule is used to indicate the way for the root UPF network element to forward the multicast data; The multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; Determining the root user plane function UPF network element includes: Regarding the UPF network element directly connected to all UPF network elements in the multicast group as the root UPF network element; or, Regarding the UPF network element with the largest number of terminal UEs among the UPF network elements directly connected to the base station gNB within the multicast group as the root UPF network element; or, Regarding the UPF network element with the least user plane traffic as the root UPF network element.

24. A point-to-multipoint data transmission device, characterized in that, Applied to the root UPF network element, where the root UPF network element is used to receive multicast data and forward the multicast data to the UPF network elements within the multicast group, including: A first receiving module, configured to receive a first N4 session establishment request message sent by a session management function (SMF) network element; the first N4 session establishment request message contains a first data forwarding rule; A second sending module, configured to forward multicast data according to the first data forwarding rule; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; The root UPF network element is a UPF network element directly connected to all UPF network elements in the multicast group; or, the root UPF network element is the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group; or, the root UPF network element is the UPF network element with the least user plane traffic.

25. A point-to-multipoint data transmission device, characterized in that, Including: A second receiving module, configured to receive a second N4 session establishment request message sent by a session management function (SMF) network element; The second N4 session establishment request message contains a second data forwarding rule; the second data forwarding rule is used to indicate the way for other UPF network elements within the multicast group to forward multicast data; the multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network; A third sending module, configured to forward multicast data according to the second data forwarding rule; Wherein, forwarding the multicast data according to the second data forwarding rule includes: Receiving multicast data sent by the directly connected base station gNB; sending the multicast data to the root user plane function (UPF) network element; or, Receiving multicast data sent by the root UPF network element; sending the multicast data to the gNB; Wherein, the root UPF network element is used to receive multicast data and forward the multicast data to the UPF network elements within the multicast group; The root UPF network element is a UPF network element directly connected to all UPF network elements in the multicast group; or, the root UPF network element is the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group; or, the root UPF network element is the UPF network element with the least user plane traffic.

26. A point-to-multipoint data transmission device, characterized in that, Including: A third receiving module, configured to receive multicast data sent by the root user plane function (UPF) network element; The multicast data is point-to-multipoint T2mT data in the space-air-ground integrated network, and the root UPF network element is used to receive multicast data and forward the multicast data to the UPF network elements within the multicast group; A fourth sending module, configured to multiplex the radio bearer of the unicast session and send the multicast data to the UE if it is determined that the radio bearer of the unicast session existing with the terminal UE meets the quality of service (QoS) of the multicast session; The root UPF network element is a UPF network element directly connected to all UPF network elements in the multicast group; or, the root UPF network element is the UPF network element with the largest number of terminal UEs included in the directly connected base station gNB within the multicast group; or, the root UPF network element is the UPF network element with the least user plane traffic.

27. A processor-readable storage medium, characterized in that, The processor-readable storage medium stores a computer program, and the computer program is used to cause the processor to execute the method according to any one of claims 1 to 11.

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