Communication method and device

Abstract

A communication method and apparatus are provided. In this method, a first network device receives a request message, which is used to request the creation of a first broadcast session for a first PLMN, and the first broadcast session is a session for a first broadcast service. If the first network device determines, based on the request message, that the first broadcast session and the second broadcast session belong to the first broadcast service session, and that the second broadcast session is a session created for a second PLMN, the first network device sends first instruction information to the second network device, which instructs that a first transmission channel not be set up for the first broadcast session, and the first transmission channel is a channel for transmitting the first broadcast service. According to the above method, when it is determined that the first broadcast session and the second broadcast session belong to the first broadcast service session, the first network device may also instruct the second network device that it does not need to set up a channel used to transmit the first broadcast service, thereby saving network resources and improving network resource utilization efficiency.

Description

Technical Field

[0005]

[0001] [Cross - reference to Related Applications] This application claims priority based on Chinese Patent Application No. 202310410430.X, titled "COMMUNICATION METHOD AND APPARATUS", filed with the China National Intellectual Property Administration on April 7, 2023, the entire content of which is incorporated herein by reference.

[0002] [Technical Field] Embodiments of this application relate to the field of wireless communication, and in particular, to communication methods and apparatuses.

Background Art

[0003] To avoid repeated construction of network infrastructure as much as possible, save the overall network investment, relieve the huge financial pressure on the construction of the 5th generation (5G) mobile communication system, and accelerate the commercial use of the 5G mobile communication system, it may be considered to strengthen the intensity of network co - construction and sharing. Radio Access Network (RAN) sharing mainly means that the RAN can be connected to the core network nodes of multiple operators. Multiple operators may co - construct the RAN, or one operator may construct the RAN independently, and other operators may borrow the operator's RAN.

[0004] In the RAN sharing scenario, multiple Public Land Mobile Networks (PLMNs) can set up sessions for the same broadcast service. Therefore, how to save network resources in the session setup process of the same broadcast service is a problem worthy of attention.

Summary of the Invention

Means for Solving the Problems

[0005] This invention provides a communication method and apparatus for saving network resources in a scenario where multiple PLMNs set up sessions for the same broadcast service.

[0006] In a first aspect, the present invention provides a communication method. The method includes: a step in which a first network device receives a request message, the request message being used to request the creation of a first broadcast session for a first public land mobile network (PLMN), the first broadcast session being a session for a first broadcast service; a step in which the first network device determines, based on the request message, that a first broadcast session and a second broadcast session belong to the first broadcast service session, the second broadcast session being a session created for a second PLMN; and a step in which the first network device transmits first instruction information to a second network device, the first instruction information indicating not to set up a first transmission channel for the first broadcast session, the first transmission channel being a channel for transmitting the first broadcast service.

[0007] In the aforementioned design, when the first network device determines, based on a request message, that the first broadcast session and the second broadcast session belong to the first broadcast service session, the first network device may instruct the second network device that it does not need to set up a channel used to transmit the first broadcast service, thereby saving network resources and improving network resource utilization efficiency.

[0008] In a possible design, the request message includes a first temporary multicast group identifier and a first broadcast service identifier, the first temporary multicast group identifier including a first PLMN identifier.

[0009] In a possible design, there is a second transmission channel set up for a second broadcast session before the first broadcast session is created, and this second transmission channel is the channel for transmitting the first broadcast service.

[0010] In a possible design, before the first network device sends the first instruction information to the second network device, the first network device sends the second instruction information to the third network device, which instructs the third network device not to set up the first transmission channel for the first broadcast session.

[0011] In the aforementioned design, the third network device may, based on the second instruction information, not assign the address information of the first transmission channel, for example, F1-U TNL CU, to the first broadcast session, thereby saving network resources.

[0012] In a possible design, the first network device receives address information for the first transmission channel from the third network device, and the address information for the first transmission channel is null or invalid.

[0013] In a possible design, the first network device sends third instruction information to the third network device, which instructs the third network device not to set up a third transmission channel for the first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device.

[0014] In the aforementioned design, the third network device may not assign the address information of the third transmission channel, such as NG-U GTP DL TEID, to the first broadcast session based on the third instruction information, thereby saving network resources.

[0015] In a possible design, in a unicast scenario, the first network device receives address information for the third transmission channel from the third network device, and the address information for the third transmission channel is null or invalid.

[0016] In a possible design, a third network device would skip joining the multicast group in a multicast scenario.

[0017] In the aforementioned design, the third network device may not join the multicast group based on the third instruction information, and as a result, the NG-U tunnel between the third network device and the first core network device is not set up.

[0018] In a possible design, the first network device sends a fourth instruction to the first core network device, which instructs not to set up a third transmission channel for the first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device.

[0019] In the aforementioned design, the first core network device may be instructed not to set up address information for the first transmission channel, for example, the NG-U tunnel.

[0020] In a possible design, the first network device receives request messages from the first core network device.

[0021] In a possible design, the first network device is a CU or a CU-CP, and the second network device is a DU.

[0022] In a possible design, the first network device sends fifth indication information to the second network device, and the fifth indication information instructs not to set up a third transmission channel for a first broadcast session, and the third transmission channel is a channel for transmitting a first core network device and a first broadcast service.

[0023] In the foregoing design, the second network device may instruct the first core network device not to set up an NG-U tunnel.

[0024] In a possible design, after the first network device sends first indication information to the second network device, the second network device sends sixth indication information to a third network device, and the sixth indication information instructs the third network device to release a first transmission channel.

[0025] In the foregoing design, based on the sixth indication information, the third network device may release address information assigned to a first broadcast session, for example, F1-U TNL CU, thereby saving network resources.

[0026] In a possible design, the first network device receives a request message from the second network device.

[0027] In a possible design, the first network device is a DU, and the second network device is a CU-CP or a CU.

[0028] In a possible design, the first network device provides services to a first PLMN and a second PLMN.

[0029] According to a second aspect, the present application provides a communication method. The method includes the step that a first network device receives a request message, where the request message is used to request to create a first broadcast session for a first PLMN, and the first broadcast session is a session of a first broadcast service; the step that the first network device determines, based on the request message, that the first broadcast session and a second broadcast session belong to a session of the first broadcast service, where the second broadcast session is a session created for a second PLMN; and the step that the first network device transmits indication information 1 to a second network device, where the indication information 1 instructs not to transmit data of the first broadcast service from the first PLMN or not to transmit data of the first broadcast service from the second PLMN.

[0030] In the foregoing method, in order to avoid redundancy caused by transmitting data of the same first broadcast service on all F1-U tunnels, the indication information 1 instructs not to transmit data of the first broadcast service from the first PLMN or not to transmit data of the first broadcast service from the second PLMN. That is, the data may be selected to be transmitted on one of the F1-U tunnels, and the data is prohibited from being transmitted on other F1-U tunnels, thereby avoiding the transmission of redundant data of the first broadcast service.

[0031] In a possible design, before the first network device transmits the indication information 1 to the second network device, the first network device determines the indication information 1 based on the session information of the first broadcast session and the session information of the second broadcast session.

[0032] In a possible design, the session information for a first broadcast session includes at least one of the following: the number of adjacent cells corresponding to the first broadcast session, the quality of service parameters corresponding to the first broadcast session, and the number of terminal devices corresponding to the first broadcast session; and the session information for a second broadcast session includes at least one of the following: the number of adjacent cells corresponding to the second broadcast session, the quality of service parameters corresponding to the second broadcast session, and the number of terminal devices corresponding to the second broadcast session.

[0033] In a possible design, if instruction 1 indicates that the first PLMN should not transmit data for the first broadcast service, the first network device sends instruction 2 to the second network device, which instructs the first PLMN to resume transmitting data for the first broadcast service; or, if instruction 1 indicates that the second PLMN should not transmit data for the first broadcast service, the first network device sends instruction 3 to the second network device, which instructs the second PLMN to resume transmitting data for the first broadcast service.

[0034] In the aforementioned design, if a problem occurs in the broadcast session for transmitting the first broadcast service, another PLMN's broadcast session may be used in a timely manner to transmit the data; that is, another F1-U tunnel may be selected in a timely manner to transmit the data, thereby reducing data transmission delay.

[0035] In a possible design, the first network device provides services to the first PLMN and the second PLMN.

[0036] In possible designs, the first network device is a CU-CP and the second network device is a CU-UP, or the first network device is a DU and the second network device is a CU-CP.

[0037] According to a third aspect, the present application provides a communication device. The device is a first network device or a chip within a first network device, and the device includes a transceiver unit and a processing unit. The transceiver unit is configured to receive a request message, which is used to request the creation of a first broadcast session for a first PLMN, the first broadcast session being a session for a first broadcast service, the processing unit is configured to determine, based on the request message, that a first broadcast session and a second broadcast session belong to the first broadcast service session, the second broadcast session being a session created for a second PLMN, the transceiver unit is configured to transmit first instruction information to a second network device, the first instruction information instructing not to set up a first transmission channel for the first broadcast session, the first transmission channel being a channel for transmitting the first broadcast service.

[0038] In a possible design, the request message includes a first temporary multicast group identifier and a first broadcast service identifier, the first temporary multicast group identifier including a first PLMN identifier.

[0039] In a possible design, there is a second transmission channel set up for a second broadcast session before the first broadcast session is created, and this second transmission channel is the channel for transmitting the first broadcast service.

[0040] In a possible design, the transceiver unit is configured to send a second instruction to a third network device before sending a first instruction to a second network device, the second instruction instructing the third network device not to set up a first transmission channel for the first broadcast session.

[0041] In a possible design, the transceiver unit is configured to receive address information for a first transmission channel from a third network device, where the address information for the first transmission channel is null or an invalid value.

[0042] In a possible design, the transceiver unit is configured to transmit a third instruction to a third network device, which instructs the third network device not to set up a third transmission channel for the first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device.

[0043] In a possible design, the transceiver unit is configured to receive address information for a third transmission channel from a third network device in a unicast scenario, where the address information for the third transmission channel is null or invalid.

[0044] In a possible design, the transceiver unit is configured to transmit a fourth instruction to a first core network device, which instructs not to set up a third transmission channel for a first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device.

[0045] In a possible design, the transceiver unit is configured to receive request messages from a first core network device when it receives a request message.

[0046] In a possible design, the first network device is a CU or CU-CP, and the second network device is a DU.

[0047] In a possible design, the transceiver unit is configured to transmit a fifth instruction to a second network device, which instructs not to set up a third transmission channel for the first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device.

[0048] In a possible design, the transceiver unit is configured to receive request messages from a second network device when it receives a request message.

[0049] In a possible design, the first network device is the DU, and the second network device is the CU-CP or CU.

[0050] In a possible design, the first network device provides services to the first PLMN and the second PLMN.

[0051] For the technical effects of the third aspect, please refer to the corresponding technical effects of the first aspect.

[0052] In a fourth aspect, the present application further provides an apparatus that can perform the method design described above. The apparatus may be a chip or circuit, or a device including a chip or circuit, that can perform the function corresponding to the method described above.

[0053] In a possible implementation, the device includes memory configured to store computer executable program code and a processor coupled to the memory. The program code stored in memory includes instructions. When the processor executes instructions, the device or the device on which the device is installed can perform the actions described in any of the possible designs described above.

[0054] The device may further include a communication interface. The communication interface may be a transceiver. Alternatively, if the device is a chip or circuit, the communication interface may be the chip's input / output interface, for example, input / output pins.

[0055] In possible designs, the device includes corresponding functional units, each configured to perform the steps in the method described above. The functions may be implemented by hardware, or by hardware running corresponding software. The hardware or software includes one or more units corresponding to the functions described above.

[0056] According to a fifth aspect, the present invention provides a computer-readable storage medium that stores a computer program. When the computer program is executed on the device, a method in any one of the possible designs described above is performed.

[0057] According to the sixth aspect, the present application provides a computer program product, which includes a computer program. When the computer program is executed on a device, the method in any one of the possible designs described above is performed. [Brief explanation of the drawing]

[0058] [Figure 1] This figure shows the data transmission process for the MBS service according to the present invention.

[0059] [Figure 2] This figure shows the interface relationships in the CU-DU architecture according to the present invention.

[0060] [Figure 3A] This figure shows the network architecture of MOCN according to the present invention.

[0061] [Figure 3B] This figure shows the MORAN network architecture according to the present invention.

[0062] [Figure 4A] This figure shows the network architecture in which CUs and DUs are shared according to the present invention.

[0063] [Figure 4B] This figure shows a network architecture shared only by the DU related to this application.

[0064] [Figure 5] This figure shows the broadcast session setup procedure according to the present invention.

[0065] [Figure 6] This is a schematic flowchart of the communication method according to this application.

[0066] [Figure 7] This figure shows the broadcast session setup procedure initiated by PLMN 2 5GC according to the present invention.

[0067] [Figure 8] This figure shows the other broadcast session setup procedure initiated by PLMN 2 5GC according to the present invention.

[0068] [Figure 9] This figure shows further additional broadcast session setup procedures initiated by 5GC of PLMN 2 according to the present invention.

[0069] [Figure 10] This is a schematic flowchart of other communication methods according to this invention.

[0070] [Figure 11]This figure shows the structure of the communication device relating to the present invention.

[0071] [Figure 12] This figure shows the results for other communication devices according to the present invention. [Modes for carrying out the invention]

[0072] In embodiments of this application, “at least one” means one or more, and “multiple” means two or more than two. The terms “and / or” describe a relational relationship between the related objects and indicate that three relationships may exist. For example, A and / or B may indicate: only A exists, both A and B exist, and only B exists, where A and B can be singular or plural. The letter “ / ” usually indicates an “or” relationship between the related objects. “At least one of the following elements (items)” or similar expressions indicate any combination of these items, including any single item (element) or any combination of multiple items (elements). For example, at least one item (element) of a, b, or c may represent a, b, c, a and b, a and c, b and c, or a, b and c, where each of a, b, and c may be an element or a set containing one or more elements.

[0073] In this application, “example,” “in some embodiments,” and “in some other embodiments” are used to indicate that an example, illustration, or explanation is being given. Any embodiment or design solution described as an “example” in this application should not be described as being preferable to or having more advantages than other embodiments or design solutions. More precisely, the term “example” is intended to present a concept in a concrete way.

[0074] In this application, “of,” “corresponding, relevant,” and “corresponding” may sometimes be used interchangeably. Unless the difference is emphasized, they express the same meaning. In embodiments of this application, “communication” and “transmission” may sometimes be used interchangeably. Unless the difference is emphasized, they express the same meaning. For example, “transmission” may include sending and / or receiving, and can be a noun or a verb.

[0075] In the embodiments of this application, words such as "first" and "second" are used solely for the purpose of distinguishing descriptions and should not be understood as indicating or suggesting relative importance, or indicating or suggesting order.

[0076] To facilitate understanding of the embodiments of this application, some basic concepts in these embodiments will be briefly explained.

[0077] 1. Multicast and broadcast service (MBS)

[0078] MBS (Mobile Broadcast Services) are services for multiple terminal devices, such as live streaming services, public security services, and batch software update services.

[0079] The data for the MBS service originates from a data server. Figure 1 shows the data transmission process for the MBS service. First, the data server sends the MBS service data to a core network device, then the core network device sends the MBS service data to a base station, and finally the base station sends the MBS service data to at least one terminal device that receives the MBS service data.

[0080] When a core network device transmits MBS service data to a base station, the MBS service data is transmitted through a transmission channel corresponding to an MBS session, and each MBS session may include at least one MBS quality of service (QoS) flow.

[0081] When a base station transmits MBS service data to a terminal device, the data packets are transmitted through an MBS radio bearer. There are two transmission methods for a single MBS radio bearer: point-to-multipoint (PTM) transmission and point-to-point (PTP) transmission.

[0082] 2. Multicast Service

[0083] Multicast services are designed for services with high QoS requirements and can provide the same QoS level as unicast services. For multicast services, the core network device also needs to manage the joining and leaving of terminal devices in multicast groups. Because transmission between the core network device and base stations relies on protocol data unit sessions (PDU sessions), a new MBS QoS flow is introduced.

[0084] The base station supports transmitting data to terminal devices using PTP and PTM transmission methods, and supports dynamic switching control between PTP and PTM transmission methods. Multicast services can only be provided to terminal devices in a radio resource control (RRC) connection state, and the base station and core network devices must maintain information about terminal devices corresponding to multicast groups. In addition, deactivation or activation of MBS sessions triggered by core network devices is also supported for multicast services, and terminal devices do not detect the state of the MBS service.

[0085] 3. CU-DU Architecture

[0086] CU stands for central unit, and DU stands for distributed unit. The CU-DU architecture, also known as the CU-DU separated base station architecture, is a new base station architecture introduced in 5G. In the fourth-generation (4G) mobile communication system architecture, base stations are deployed independently and connected separately to the 4G core network. In the 5G architecture, the DU portions of different base stations are deployed independently, but the CU portions of different base stations are deployed centrally.

[0087] From a physical modular structure perspective, a 4G base station is internally divided into several modules: a building baseband unit (BBU), a remote radio unit (RRU), and an antenna. Each base station has a set of BBUs, which connect directly to the core network. In the 5G CU-DU architecture, the original RRU and antenna are incorporated into an active antenna unit (AAU), and the BBU is divided into DUs and CUs. Each base station has a set of DUs, and multiple stations share the same CU for centralized management.

[0088] From the perspective of protocol stack structure, in the 5G CU-DU architecture, the lowest physical layer of the original 4G base station's BBU is forwarded to the AAU for processing, the upper physical layers with high real-time requirements, the medium access control (MAC) layer, and the radio link control (RLC) layer are placed in the DU for processing, and the packet data convergence protocol (PDCP) layer, service data adaptation protocol (SDAP) layer, RRC layer, etc., with lower real-time requirements are placed in the CU for processing.

[0089] In the CU-DU architecture, the interface between the CU and DU is called the F1 interface. The CU may be further divided into CU-CP and CU-UP. CU-CP is the central unit-control plane, and CU-UP is the central unit-user plane.

[0090] The interface between a CU-CP and a CU-UP is called the E1 interface. Typically, a base station has only one CU-CP, multiple CU-UPs, and a DU. One DU can be connected to only one CU-CP, and one CU-UP can also be connected to only one CU-CP. The interface between a CU-CP and a DU is called the F1-C (control plane), and the interface between a CU-UP and a DU is called the F1-U (user plane). It can be seen that there can be multiple F1-Us between one DU and multiple CU-UPs. F1-Us are typically used for data transmission and may also be called F1-U tunnels, as shown in Figure 2.

[0091] 4. RAN sharing

[0092] The following explains RAN sharing from the perspectives of resource sharing strength, service independence, and other factors.

[0093] A multi-operator core network (MOCN) can also be called a shared carrier frequency network. In this sharing scheme, the core networks are independent. Configuration management, alarm management, and performance indicators must all be managed by the primary operator. Some performance indicators may distinguish PLMN for monitoring purposes, and features cannot be activated independently. BBUs, RRUs, or AUUs are shared, and specific carrier segments or multiple specific carrier segments from different operators are shared to form a shared carrier with a continuous large bandwidth, which can result in reduced infrastructure and device costs, as shown in Figure 3A.

[0094] A multi-operator radio access network (MORAN) can also be called a carrier frequency division sharing network. In this sharing scheme, the core network is independent, 5G RAN devices are shared, and cells and spectrums are independent. Configuration management, alarm management, etc., must all be managed by the primary operator. Performance indicators may be distinguished for monitoring, and cell-level characteristics may be planned and activated independently. The BBU is shared and connected to RRU / AAUs from the same vendor. As shown in Figure 3B, the operators of the RRU / AAUs are independent of each other, the carriers are configured and managed independently, and different logically independent cells are provided to multiple operators within the base station for independent use.

[0095] In this application, it should be further understood that RAN sharing and base station contributions are mutually interchangeable.

[0096] The embodiments of this application are primarily applicable to MOCN scenarios, but may also be applicable to other scenarios. This is not limited to these. Below, only some possible RAN sharing architectures in MOCN scenarios are described.

[0097] RAN shared architecture 1 is an architecture in which CUs and DUs are shared.

[0098] The PLMN core network is configured independently, while the PLMN's CUs and DUs are shared.

[0099] As shown in Figure 4A, the 5G core network (5G core, 5GC) of PLMN A, the 5GC of PLMN B, and the 5GC of PLMN C are configured independently. The gNB-CU of PLMN A, the gNB-CU of PLMN B, and the gNB-CU of PLMN C are shared, i.e., the gNB-CU is shared. The gNB-DU of PLMN A, the gNB-DU of PLMN B, and the gNB-DU of PLMN C are shared, i.e., the gNB-DU is shared.

[0100] For example, the 5GC for PLMN A sends a temporary multicast group identifier (TMGI) A and the broadcast service identifier to the shared gNB-CU, where TMGI A contains the identifier for PLMN A. Similarly, the 5GC for PLMN B sends TMGI B and the broadcast service identifier to the shared gNB-CU, where TMGI B contains the identifier for PLMN B. Based on the received identifiers for the two broadcast services, the shared gNB-CU determines that the broadcast services requested by the two 5GCs are the same service. Alternatively, the shared gNB-CU sends the identifiers for the two broadcast services to the shared gNB-DU, where the shared gNB-DU determines that the broadcast services requested by the two 5GCs are the same service.

[0101] RAN shared architecture 2 is an architecture in which only the DU is shared.

[0102] The PLMN core network is configured independently; PLMN CUs are not shared, but PLMN DUs are shared.

[0103] As shown in Figure 4B, the 5GCs of PLMN A, PLMN B, and PLMN C are set independently. The gNB-CU of PLMN A, PLMN B, and PLMN C are not shared, while the gNB-DU of PLMN A, PLMN B, and PLMN C are shared; in other words, the gNB-DU is shared.

[0104] Since PLMN's gNB-CU is not shared, PLMN's gNB-CU receives the TMGI and broadcast service identifiers sent by the corresponding PLMN's 5GC, and then sends the TMGI and broadcast service identifiers to the shared gNB-DU. The shared gNB-DU determines that the broadcast services requested by different 5GCs are the same service.

[0105] It should be further understood that in this application, each network element is described using only the names of network elements in a 5G network as an example. Other naming conventions may be used in other future networks, and this is not limited to this application.

[0106] 4. NG Interface

[0107] The NG interface is the interface between the evolved node B (gNB) and the 5GC in a 5G system (5GS). The NG interface is divided into the NG-C interface (control plane interface between the gNB and the 5GC) and the NG-U interface (user plane interface between the gNB and the 5GC).

[0108] Figure 5 shows the current broadcast session setup procedure.

[0109] S501:5GC sends a Broadcast Session Setup Request (NGAP Broadcast Session Setup Request) message to gNB-CU-CP, which includes TMGI. In addition, the message may further include at least one of the following: slice information, 5G QoS file, area information, and transport layer information.

[0110] For example, in an NG-U multicast transmission scenario, the transport layer information includes the IP multicast address and the source-specific IP multicast address (which may also be represented as 5G core network NG-U transport layer address information (5GC NG-U TNL)). NG-U multicast may also be referred to as N3mb multicast, and specifically, a common GTP-U tunnel is used for each MBS session, and NG-U multicast is abbreviated as multicast in this application.

[0111] In an NG-U unicast transmission scenario, transport layer information includes a General-Package Radio Service Tunneling Protocol Uplink Tunnel Endpoint Identifier (GPRS tunneling protocol uplink tunnel endpoint identifier, GTP UP TEID) (which may also be indicated as 5GC NG-U TNL). NG-U unicast is sometimes referred to as N3mb unicast, and specifically, a separate GTP-U tunnel is used for each MBS session; in this application, NG-U unicast is abbreviated as unicast.

[0112] gNB-CU-CP may choose to transmit data using NG-U multicast or NG-U unicast.

[0113] S502: gNB-CU-CP sends a Broadcast Bearer Context Setup Request (E1AP BC Bearer Context Setup Request) message to gNB-CU-UP.

[0114] The message contains transport layer information from 5GC. The specific type of transport layer information to be carried depends on whether gNB-CU-CP selects NG-U multicast or NG-U unicast.

[0115] S503: gNB-CU-UP sends a Broadcast Bearer Context Setup Response (E1AP BC Bearer Context Setup Response) message to gNB-CU-CP.

[0116] In an NG-U multicast transmission scenario, the message includes the F1-U transport layer address information of the CU (F1-U TNL CU). The F1-U TNL CU includes the F1-U GTP UL TEID.

[0117] In an NG-U unicast transmission scenario, the message includes an NG-U GTP DL TEID (which may also be represented as a gNB NG-U TNL) and an F1-U TNL CU, the F1-U TNL CU containing an F1-U GTP UL TEID.

[0118] S504: In the NG-U multicast transmission scenario, gNB-CU-UP joins the NG-U multicast group.

[0119] In the NG-U multicast transmission scenario, the gNB-CU-CP sets up an NG-U tunnel with 5GC.

[0120] S505:gNB-CU-CP sends a Broadcast Context Setup Request (F1AP) message to the DU.

[0121] The message includes MRB configuration information, other relevant session parameters, etc. In addition, optionally, the message may further include F1-U GTP UL TEID.

[0122] S506:DU sends a Broadcast Context Setup Response (F1AP) message to gNB-CU-CP.

[0123] The message includes F1-U GTP DL TEID (which may also be shown as F1-U TNL DU).

[0124] S507: gNB-CU-CP sends a Broadcast Bearer Context Modification Request (F1AP BC Bearer Context Modification Request) to gNB-CU-UP.

[0125] Optionally, the message includes F1-U GTP DL TEID.

[0126] S508: gNB-CU-UP sends a Broadcast Bearer Context Modification Response (F1AP BC Bearer Context Modification Response) to gNB-CU-CP.

[0127] S509:DU provides broadcast configuration information to UE.

[0128] For example, a DU configures broadcast resources and provides broadcast configuration information to a UE via a multicast control channel (MBS control channel, MCCH).

[0129] S510:gNB-CU-CP sends a Broadcast Session Setup Response (NGAP Broadcast Session Setup Response) message to 5GC.

[0130] In the NG-U unicast transmission scenario, the message includes an NG-U GTP DL TEID, which is from S503. In this case, the gNB-CU-CP sets up an NG-U tunnel with 5GC.

[0131] From the process described above, it can be seen that a data transmission channel, also known as an NG-U tunnel, can be set up through the interaction between 5GC and gNB.

[0132] The F1-U tunnel can be set up through the interaction between the gNB-CU and the gNB-DU. In addition, the F1-U tunnel is set up between the gNB-CU and the gNB-DU, conditional on the broadcast session setup procedure being initiated. That is, the NG-U tunnel setup and the F1-U tunnel setup are independent of each other.

[0133] During the current discussion, when multiple PLMNs share a base station, if multiple PLMNs create broadcast sessions for the same broadcast service, the base station may determine the amount of NG-U tunnels to be set up in order to conserve resources. The base station can determine the amount of NG-U tunnels whether or not they should be set up, but as can be seen from the analysis above, F1-U tunnels are always set up whenever the broadcast session setup procedure is initiated.

[0134] For example, in a RAN sharing scenario, there are a total of five PLMNs. For the same broadcast service, if the base station decides to set up all five NG-U tunnels, then five F1-U tunnels will be clearly set up between the gNB-CU and gNB-DU. If the base station decides to set up only one NG-U tunnel, the broadcast sessions for the remaining four PLMNs still need to be set up, but the NG-U tunnels will not be set up. However, the five F1-U tunnels will still be set up in this process. Therefore, even if there is only one NG-U tunnel, there are still five F1-U tunnels.

[0135] To conserve network resources in a scenario where multiple PLMNs set up sessions for the same broadcast service, this application provides a communication method. This method includes the following steps:

[0136] As shown in Figure 6, the method includes the following steps.

[0137] 601: The first network device receives a request message, which is used to request the creation of a first broadcast session for the first PLMN, the first broadcast session being a session for the first broadcast service.

[0138] For example, a request message includes a first temporary multicast group identifier and a first broadcast service identifier, the first temporary multicast group identifier including a first PLMN identifier.

[0139] 602: The first network device determines, based on the request message, that the first broadcast session and the second broadcast session belong to the first broadcast service session, and the second broadcast session is a session created for the second PLMN.

[0140] The second broadcast session is set up before the first broadcast session, and the second broadcast session is the broadcast session that has already been set up.

[0141] The first network device provides services to the first PLMN and the second PLMN. In addition, the first network device may also provide services to other PLMNs, although this is not limited to the present invention.

[0142] For example, the first network device may determine whether the broadcast service corresponding to the first broadcast session is the same as the broadcast service corresponding to the second broadcast session. If the broadcast service corresponding to the first broadcast session is the same as the broadcast service corresponding to the second broadcast session, it may determine that the first and second broadcast sessions belong to the same broadcast service session. Otherwise, it may determine that the first and second broadcast sessions belong to different broadcast service sessions.

[0143] The first network device's determination, based on the request message, that the first broadcast session and the second broadcast session belong to the first broadcast service session can also be described as the first network device determining, based on the request message, that the first broadcast service session already exists, or that the first broadcast service session is set up for another PLMN.

[0144] 603: The first network device transmits first instruction information to the second network device, which instructs not to set up a first transmission channel for a first broadcast session, and the first transmission channel is a channel for transmitting a first broadcast service.

[0145] In possible designs, the first transmission channel is either an F1-U tunnel or an NG-U tunnel.

[0146] For example, before the first broadcast session is created, there is a second transmission channel set up for the second broadcast session, and this second transmission channel is the channel for transmitting the first broadcast service. The type of the second transmission channel is the same as the type of the first transmission channel. For example, the second transmission channel is also an F1-U tunnel, and the second transmission channel is also used to transmit the first broadcast service.

[0147] In the aforementioned design, when the first network device determines, based on a request message, that the first broadcast session and the second broadcast session belong to the first broadcast service session, the first network device may instruct the second network device that it does not need to set up a channel used to transmit the first broadcast service, thereby saving network resources and improving network resource utilization efficiency.

[0148] The following describes several RAN sharing scenarios in more detail.

[0149] Scenario 1: The first network device is a CU, and the second network device is a DU.

[0150] For example, with respect to 601, the first network device may receive a request message from the first core network device.

[0151] In addition, in a possible design, in a unicast scenario, the first network device may further transmit a fourth instruction to the first core network device, which instructs not to set up a third transmission channel for the first broadcast session, the third transmission channel being a channel for transmitting the first core network device and the first broadcast service. The third transmission channel may be an NG-U tunnel. In the aforementioned design, the first core network device may be instructed not to set up a third transmission channel, such as an NG-U tunnel.

[0152] For further details, please refer to the relevant descriptions in Embodiment 1 below.

[0153] Scenario 2: The first network device is CU-CP, the second network device is DU, and the third network device is CU-UP.

[0154] In addition to the above description of Scenario 1, in a possible design, the first network device further transmits second instruction information to the third network device, which instructs the third network device not to set up the first transmission channel for the first broadcast session. Furthermore, the first network device may receive address information for the first transmission channel from the third network device, which is null or invalid. In the above design, the third network device may, based on the second instruction information, not assign the address information for the first transmission channel, for example, F1-U TNL CU, to the first broadcast session, thereby saving network resources.

[0155] In other possible designs, the first network device may further transmit third instruction information to a third network device, which instructs the third network device not to set up a third transmission channel for the first broadcast session, and the third transmission channel is a channel for transmitting the first core network device and the first broadcast service. The third transmission channel may be an NG-U tunnel.

[0156] Furthermore, in a unicast scenario, the first network device may receive address information for a third transmission channel from the third network device, where the address information for the third transmission channel is null or invalid. In the aforementioned design, the third network device may, based on the third instruction information, not assign the address information for the third transmission channel, for example, NG-U GTP DL TEID, to the first broadcast session, thereby saving network resources.

[0157] In a multicast scenario, the third network device does not join the multicast group. In the design described above, the third network device may not join the multicast group based on the third instruction information, and as a result, the NG-U tunnel between the third network device and the first core network device is not set up.

[0158] For further details, please refer to the relevant description in Embodiment 2 below.

[0159] Scenario 3: The first network device is a DU, and the second network device is a CU-CP or CU.

[0160] For example, in 601, a second network device may receive a broadcast session setup request message from the first core network device. Based on the broadcast session request message, the second network device sends a request message to the first network device.

[0161] In a possible design, in a unicast scenario, the first network device sends a fifth instruction to the second network device, which instructs not to set up a third transmission channel for the first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device. The third transmission channel may be an NG-U tunnel. The second network device may further send a fourth instruction to the first core network device, which instructs not to set up a third transmission channel for the first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device. In the above design, the first core network device may be instructed not to set up a third transmission channel, such as an NG-U tunnel.

[0162] For further details, please refer to Embodiment 3 below.

[0163] Scenario 4: The first network device is a DU, and the second network device is a CU-CP.

[0164] In addition to the above description of Scenario 3, after the first network device sends the first instruction information to the second network device, the second network device sends the sixth instruction information to the third network device, which instructs the third network device to release the first transmission channel. In the above design, the third network device may, based on the sixth instruction information, release the address of the first transmission channel that is assigned to the first broadcast session, for example, F1-U TNL CU, thereby saving network resources.

[0165] For further details, please refer to Embodiment 3 below. Embodiment 1:

[0166] As shown in Figure 7, in the scenario described in Embodiment 1 below, the gNB is divided into gNB-CU and gNB-DU. PLMN 1 and PLMN 2 share gNB-CU and gNB-DU. The 5GC of PLMN 1 initiates the broadcast session setup procedure for PLMN 1, and the broadcast session set up for PLMN 1 is the session for broadcast service x. Then, the 5GC of PLMN 2 also initiates the broadcast session setup procedure, and the broadcast session set up for PLMN 2 is the session for broadcast service x. The 5GC of PLMN 1 and the 5GC of PLMN 2 are independent of each other. The fact that the 5GC of PLMN 1 initiates the broadcast session setup procedure before the 5GC of PLMN 2 is merely an example and is not intended to limit the present invention.

[0167] The broadcast session setup procedure initiated by PLMN 2's 5GC may specifically include the following steps:

[0168] S701:5GC sends a broadcast session setup request message to the gNB-CU, the message containing identifiers for TMGI 2 and broadcast service X, where TMGI 2 contains identifier for PLMN 2.

[0169] S702:gNB-CU determines that both the broadcast session set up for PLMN 2 and the broadcast session set up for PLMN 1 belong to the broadcast service X session.

[0170] S703: The gNB-CU sends a broadcast context setup request to the gNB-DU.

[0171] The message includes a first instruction, which instructs not to set up the F1-U tunnel for the PLMN 2 broadcast session.

[0172] Specifically, the message includes the gNB-CU's F1-U tunnel address information (BC Bearer Context F1-U TNL Info at CU), and this information is optional. If the gNB-CU decides to send the first instruction information, it may ignore the information; that is, the broadcast context setup request does not include the information.

[0173] S704: The gNB-DU sends a broadcast context setup response to the gNB-CU.

[0174] For example, a message may contain gNB-DU F1-U tunnel address information (BC Bearer Context F1-U TNL Info at DU), which is essential information and may carry null or invalid values.

[0175] S705:DU provides broadcast configuration information to the UE.

[0176] S706:gNB-CU sends a broadcast session setup response message to 5GC.

[0177] For example, in a unicast scenario, the message may include a fourth directive, which indicates not to set up an NG-U tunnel for a PLMN 2 broadcast session. The fourth directive is optional information. Embodiment 2:

[0178] As shown in Figure 8, in the scenario shown in Embodiment 1, the gNB is divided into gNB-CU and gNB-DU, and the gNB-CU is divided into gNB-CU-CP and gNB-CU-UP. PLMN 1 and PLMN 2 share gNB-CU-CP, gNB-CU-UP, and gNB-DU. The 5GC of PLMN 1 initiates the broadcast session setup procedure for PLMN 1, and the broadcast session set up for PLMN 1 is the session for broadcast service x. Then, the 5GC of PLMN 2 also initiates the broadcast session setup procedure, and the broadcast session set up for PLMN 2 is the session for broadcast service x. The 5GC of PLMN 1 and the 5GC of PLMN 2 are independent of each other. The fact that the 5GC of PLMN 1 initiates the broadcast session setup procedure before the 5GC of PLMN 2 is merely an example and is not intended to limit the present invention.

[0179] The broadcast session setup procedure initiated by PLMN 2's 5GC may specifically include the following steps:

[0180] S801:5GC sends a broadcast session setup request message to gNB-CU-CP, the message containing identifiers for TMGI 2 and broadcast service X, where TMGI 2 contains the identifier for PLMN 2.

[0181] S802:gNB-CU-CP determines that both the broadcast session set up for PLMN 2 and the broadcast session set up for PLMN 1 belong to the broadcast service X session.

[0182] S803: gNB-CU-CP sends a broadcast bearer context setup request message to gNB-CU-UP.

[0183] The message includes a second instruction and / or a third instruction, the second of which instructs gNB-CU-UP not to set up the F1-U tunnel for the PLMN 2 broadcast session, and the third of which instructs gNB-CU-UP not to set up the NG-U tunnel for the PLMN 2 broadcast session. The second and third instructions are optional.

[0184] S804: gNB-CU-UP sends a broadcast bearer context setup response to gNB-CU-CP.

[0185] Based on the second instruction information, gNB-CU-UP may not assign the F1-U TNL CU to the PLMN 2 broadcast session. Therefore, the message carries F1-U tunnel address information including gNB-CU, which is essential information, and which may carry null or invalid values.

[0186] In addition, in a unicast scenario, gNB-CU-UP may not assign an NG-U GTP DL TEID to the PLMN 2 broadcast session based on third instruction information. Therefore, the message carries NG-U tunnel address information, which is null or invalid. In a multicast scenario, gNB-CU-UP does not join the multicast group.

[0187] S805: gNB-CU-CP sends a broadcast context setup request to gNB-DU.

[0188] The message includes a first instruction, which instructs not to set up the F1-U tunnel for the PLMN 2 broadcast session.

[0189] Specifically, the message contains the gNB-CU's F1-U tunnel address information, and this information is optional. If the gNB-CU-CP decides to send the first instruction information, it may ignore the information, i.e., the broadcast context setup request does not contain any information.

[0190] S806: gNB-DU sends a broadcast context setup response to gNB-CU-CP.

[0191] For example, a message may contain gNB-DU F1-U tunnel address information, which is essential information and may carry null or invalid values.

[0192] S807: gNB-CU-CP sends a broadcast bearer context change request to gNB-CU-UP.

[0193] S808: gNB-CU-UP sends a broadcast bearer context change response to gNB-CU-CP.

[0194] S809:DU provides broadcast configuration information to the UE.

[0195] S810:gNB-CU-CP sends a broadcast session setup response message to 5GC.

[0196] For example, in a unicast scenario, the message may include a fourth directive, which indicates not to set up an NG-U tunnel for a PLMN 2 broadcast session. The fourth directive is optional information. Embodiment 3:

[0197] As shown in Figure 9, in the scenario shown in Embodiment 1, gNB is divided into gNB-CU and gNB-DU, and gNB-CU is divided into gNB-CU-CP and gNB-CU-UP. PLMN 1 and PLMN 2 either share gNB-DU, or PLMN 1 and PLMN 2 share gNB-CU-CP, gNB-CU-UP, and gNB-DU. However, gNB-DU determines whether the broadcast service is the same. Specifically, gNB-DU determines that both the broadcast session set up for PLMN 2 and the broadcast session set up for PLMN 1 belong to the same broadcast service session. PLMN 1's 5GC initiates the broadcast session setup procedure for PLMN 1, and the broadcast session set up for PLMN 1 is the service session for broadcast service x. Then, PLMN 2's 5GC also initiates the broadcast session setup procedure, and the broadcast session set up for PLMN 2 is the session for broadcast service x. The 5GCs of PLMN 1 and PLMN 2 are independent of each other. The fact that the 5GC of PLMN 1 initiates the broadcast session setup procedure before the 5GC of PLMN 2 is merely an example and is not intended to limit the present invention.

[0198] The broadcast session setup procedure initiated by PLMN 2's 5GC may specifically include the following steps:

[0199] S901:5GC sends a broadcast session setup request message to gNB-CU-CP, the message containing identifiers for TMGI 2 and broadcast service X, where TMGI 2 contains identifier for PLMN 2.

[0200] S902: gNB-CU-CP sends a broadcast bearer context setup request message to gNB-CU-UP.

[0201] S903: gNB-CU-UP sends a broadcast bearer context setup response to gNB-CU-CP.

[0202] S904: gNB-CU-CP sends a broadcast context setup request to gNB-DU.

[0203] The message includes TMGI 2 and service identifier X.

[0204] S905:gNB-DU determines that both the broadcast session set up for PLMN 2 and the broadcast session set up for PLMN 1 belong to the broadcast service X session.

[0205] S906: gNB-DU sends a broadcast context setup response to gNB-CU-CP.

[0206] For example, the message contains a first instruction that instructs not to set up an F1-U tunnel for a PLMN 2 broadcast session.

[0207] In addition, the message includes gNB-DU F1-U tunnel address information, which is essential information and may carry null or invalid values.

[0208] Optionally, the message may include a fifth instruction that instructs not to set up an NG-U tunnel for a PLMN 2 broadcast session.

[0209] S907: gNB-CU-CP sends a broadcast bearer context change request to gNB-CU-UP.

[0210] Optionally, the message may include a sixth instruction, which instructs gNB-CU-UP to release the F1-U tunnel.

[0211] S908: gNB-CU-UP sends a broadcast bearer context change response to gNB-CU-CP.

[0212] For example, gNB-CU-UP may release the F1-U tunnel based on the sixth instruction information.

[0213] S909:DU provides broadcast configuration information to the UE.

[0214] S910:gNB-CU-CP sends a broadcast session setup response message to 5GC.

[0215] For example, the message may include a fourth directive, which indicates not to set up an NG-U tunnel for a PLMN 2 broadcast session. The fourth directive is optional.

[0216] To conserve network resources in a scenario where multiple PLMNs set up sessions for the same broadcast service, this application provides a communication method. This method includes the following steps:

[0217] As shown in Figure 10, the method includes the following steps.

[0218] 1001: A first network device receives a request message, which is used to request the creation of a first broadcast session for a first PLMN, the first broadcast session being a session for a first broadcast service.

[0219] The first network device is CU-CP and the second network device is CU-UP, or the first network device is DU and the second network device is CU-CP.

[0220] 1002: The first network device determines, based on the request message, that the first broadcast session and the second broadcast session belong to the first broadcast service session, and the second broadcast session is a session created for the second PLMN.

[0221] The first network device provides services to the first PLMN and the second PLMN. See 601 and 602 for 1001 and 1002. Further details are not described again in this specification.

[0222] 1003: The first network device transmits instruction information 1 to the second network device, instructing that the first PLMN not transmit data for the first broadcast service, or that the second PLMN not transmit data for the first broadcast service.

[0223] Before the first network device transmits instruction information 1 to the second network device, the first network device determines instruction information 1 based on the session information of the first broadcast session and the session information of the second broadcast session.

[0224] The session information for the first broadcast session includes at least one of the following: the number of adjacent cells corresponding to the first broadcast session, the quality of service parameters corresponding to the first broadcast session, and the number of terminal devices corresponding to the first broadcast session. The session information for the second broadcast session includes at least one of the following: the number of adjacent cells corresponding to the second broadcast session, the quality of service parameters corresponding to the second broadcast session, and the number of terminal devices corresponding to the second broadcast session.

[0225] A broadcast session with a greater number of adjacent cells, better quality of service parameters, and / or a greater number of terminal devices is selected to transmit data for the first broadcast service, while other broadcast sessions are not used to transmit data for the first broadcast service.

[0226] In the embodiment shown in Figure 10, it should be noted that a first broadcast session is created for a first PLMN, a second broadcast session is created for a second PLMN, and there are F1-U tunnels corresponding to the first broadcast session and F1-U tunnels corresponding to the second broadcast session. To avoid redundancy caused by transmitting the same first broadcast service data on all F1-U tunnels, instruction information 1 instructs that data for the first broadcast service not be transmitted from the first PLMN, or that data for the first broadcast service not be transmitted from the second PLMN. That is, the data may be chosen to be transmitted on one of the F1-U tunnels, and the data is prohibited from being transmitted on the other F1-U tunnels, thereby avoiding the transmission of redundant data for the first broadcast service.

[0227] In addition, in a possible design, when instruction information 1 instructs the first PLMN not to transmit data for the first broadcast service, the first network device sends instruction information 2 to the second network device, which instructs the first PLMN to resume transmitting data for the first broadcast service, or when instruction information 1 instructs the second PLMN not to transmit data for the first broadcast service, the first network device sends instruction information 3 to the second network device, which instructs the second PLMN to resume transmitting data for the first broadcast service.

[0228] In the aforementioned design, if a problem occurs in the broadcast session for transmitting the first broadcast service, a broadcast session from another PLMN may be used in a timely manner to transmit the data, thereby reducing data transmission delay.

[0229] The MBS NeighbourCellList (mbs-NeighbourCellList) indicates the list of neighboring cells for an ongoing broadcast session provided by the MRB within the current cell, a list of neighboring cells that may provide a broadcast session, a list of neighboring cells that have previously provided a broadcast session, and so on. For example, the MBS NeighbourCellList for broadcast session 1 provided by cell 1 is (cellA, cellB, cellC, cellD). The MBS NeighbourCellList is determined when the F1 interface is set up or updated. Therefore, in a scenario where the CU and DU are shared (see the aforementioned architecture where the CU and DU are shared), the MBS NeighbourCellList for the CU is the same as the MBS NeighbourCellList for the DU.

[0230] The MBS neighbor cell list is typically used in conjunction with the mtch neighbor cell (mtch-NeighbourCell). The mtch neighbor cell indicates a neighbor cell that provides broadcast services on a multicast traffic channel (MTCH). If broadcast services are provided on the MTCH of the first cell in the MBS neighbor cell list, the first bit in the mtch neighbor cell indication information is set to 1; otherwise, the first bit is set to 0. All or some of the cells in the MBS neighbor cell list are mtch neighbor cells.

[0231] In a scenario where only the DU is shared, the operator's CU sends the CU's MBS neighbor cell list and mtch neighbor cell indication information to the shared DU, with the mtch neighbor cell indication information indicating a list of neighbor cells currently providing broadcast services. The MBS neighbor cell list and mtch neighbor cell indication information received by the shared DU may differ.

[0232] Therefore, the shared DU needs to process the broadcast session by referring to the MBS adjacent cell list and mtch adjacent cell indication information.

[0233] The following solution is applicable to a scenario where only the DU is shared, the shared DU serves the first PLMN and the second PLMN, and the first PLMN and the second PLMN set up separate broadcast sessions for the same broadcast service. The maximum number of cells that can be included in the MBS neighbor cell list is a preset value. For example, the maximum number of cells that can be included in the MBS neighbor cell list is 8. This is not limited to the present application.

[0234] In possible implementation 1, if all cells in the first PLMN and the second PLMN within the shared DU are shared cells, then the names may also be different, even if the order of the planned MBS neighbor cell list for the PLMN is different. Since all these cells are shared cells, the shared DU may use either the MBS neighbor cell list of the first PLMN or the MBS neighbor cell list of the second PLMN, and there is no need to regenerate the MBS neighbor cell list.

[0235] In addition, the shared DU may also decide to use the mtch adjacent cell of the first PLMN or the mtch adjacent cell of the second PLMN.

[0236] In possible implementation 2, if some cells of the first PLMN and the second PLMN within the shared DU are shared cells, the shared gNB-DU broadcasts that the MBS adjacent cell list needs to be regenerated. The specific generation method is not limited herein.

[0237] The following provides an explanation with specific examples.

[0238] Assuming that in the current shared DU, operator A has set up broadcast session 1, the shared DU receives a broadcast context setup request sent by operator B's CU-B, which is used to request the setup of broadcast session 2, and the broadcast context setup request may include mtch adjacent cell instruction information.

[0239] Specifically, depending on whether each business has non-shared cells, the following cases may occur:

[0240] (1) All cells of business operator A and business operator B within the shared DU are shared cells, which corresponds to possible implementation 1.

[0241] The area of ​​a broadcast session is determined by the application function (AF). Therefore, if all cells of both Operator A and Operator B within a shared DU are shared cells, when the shared DU receives a broadcast context setup request sent by CU-B, the shared DU may decide to use Operator A's MBS neighbor cell list or Operator B's MBS neighbor cell list if the broadcast service corresponding to the broadcast session is the same as the broadcast service corresponding to Operator A's broadcast session, and the shared cells are also the same.

[0242] Furthermore, a shared DU may decide to use either a mtch adjacent cell of Provider A or a mtch adjacent cell of Provider B. For example, when all shared cells broadcast data for a broadcast service, or when the cell indicated by Provider A's mtch adjacent cell indication information is the same as the cell indicated by Provider B's mtch adjacent cell indication information, the shared DU may decide to use either a mtch adjacent cell of Provider A or a mtch adjacent cell of Provider B. In addition, the shared DU may also decide to use either a mtch adjacent cell of Provider A or a mtch adjacent cell of Provider B in accordance with other policies. This is not limited to the present application.

[0243] (2) Operator A and Operator B have non-shared cells within the shared DU, which corresponds to possible implementation 2.

[0244] For example, the adjacent cell list (MBS adjacent cell list) sent by CU-A to the shared gNB-DU may be (cell1, cell2, cell3), and the mtch adjacent cell indication information may be represented as (1, 1, 1). The adjacent cell list (MBS adjacent cell list) sent by CU-B to the shared gNB-DU may be (cell2, cell3, cell4), and the mtch adjacent cell indication information may be represented as (1, 1, 1). The two mtch adjacent cell indication informations herein are merely examples.

[0245] The adjacent cell contents of the two operators are the same, but cell 1 of operator A and cell 4 of operator B are non-shared cells. Since a shared DU can only broadcast one MBS adjacent cell list, if the MBS adjacent cell list sent by CU-A is used, CU-A's broadcast service can be directed correctly, but CU-B's broadcast service may be directed incorrectly because CU-B's broadcast service does not exist in cell 1. Therefore, the gNB-DU needs to regenerate a new MBS adjacent cell list. For example, the new MBS adjacent cell list is (cell 1, cell 2, cell 4).

[0246] The advantage of the above method is that it guarantees that even though the broadcast service for cell 3 is not indicated, there are no errors indicated in the existing MBS neighbor cell list. For an unmodified MBS neighbor cell list, an indication error may occur in the existing neighbor cell list.

[0247] The MBS adjacent cell list primarily contains cell names or physical cell identifiers, and it should be further understood that Cell 1, Cell 2, Cell 3, and Cell 4 have the same understanding for Operator A and Operator B.

[0248] In a possible design, gNB-DU can determine whether the cell name (or physical cell identifier) ​​of each cell in the new MBS neighboring cell list has the same cell name (or the same physical cell identifier) ​​as the one in Operator A's MBS neighboring cell list. If the cell name (or physical cell identifier) ​​of each cell in the new MBS neighboring cell list has the same cell name (or the same physical cell identifier) ​​as the one in Operator A's MBS neighboring cell list, then the index corresponding to that cell in Operator A's mtch neighboring cell information is 1; otherwise, the index corresponding to that cell in Operator A's mtch neighboring cell information is 0. For example, if the new MBS neighboring cell list is (cell1, cell2, cell4), then cell1 and cell2 also exist in Operator A's MBS neighboring cell list (cell1, cell2, cell3). In this case, the index corresponding to cell1 in Operator A's mtch neighboring cell information is set to 1, and the index corresponding to cell2 is also set to 1. If cell4 is not included in the MBS adjacent cell list (cell1, cell2, cell3) of operator A, the index of cell4 in operator A's mtch adjacent cell indication information is set to 0. Therefore, operator A's mtch adjacent cell indication information may be represented as (1, 1, 0), and similarly, operator B's mtch adjacent cell indication information may be represented as (0, 1, 1).

[0249] In other possible designs, the gNB-DU may skip the aforementioned decision process and directly set the index corresponding to cell1 in the mtch adjacent cell information to 1. In this case, the mtch adjacent cell information for operator A may be represented as (1, 1, 1), and similarly, the mtch adjacent cell information for operator B may be represented as (1, 1, 1).

[0250] Furthermore, for operator A, the DU may send TMGI 1, the new MBS neighbor cell list, and operator A's mtch neighbor cell indication information to the UE by using broadcast session 1, where TMGI 1 includes operator A's PLMN ID. Operator A's mtch neighbor cell indication information indicates the cells that will actually be broadcast in operator A's new MBS neighbor cell list.

[0251] For operator B, the DU may send TMGI 2, the new MBS neighbor cell list, and operator B's mtch neighbor cell indication information to the UE by using broadcast session 2, where TMGI 2 includes operator B's PLMN ID. Operator B's mtch neighbor cell indication information indicates the cells that will actually be broadcast in operator B's new MBS neighbor cell list.

[0252] It should be noted that the newly generated MBS neighboring cell lists and mtch neighboring cell indication information for CU-A and CU-B are merely examples and are not intended to limit this application. A shared DU may further determine new MBS neighboring cell lists and mtch neighboring cell indication information corresponding to different CUs separately, in accordance with other policies. This is not limited to this application.

[0253] To implement the functions in the embodiments described above, it can be understood that the device includes corresponding hardware structures and / or software modules for performing the functions. Those skilled in the art will readily recognize, in combination with the units and method steps in the examples described in the embodiments disclosed herein, that the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether the functions are performed by hardware or by hardware driven by computer software depends on the specific application scenario and design constraints of the technical solution.

[0254] Figures 11 and 12 show possible structures of communication devices according to embodiments of the present application. These communication devices may be configured to implement the functions of a terminal or base station in the embodiments of the method described above. Thus, the beneficial effects of the embodiments of the method described above may also be implemented. In embodiments of the present application, the communication device may be the first network device shown in Figure 1, or a module (e.g., a chip) used in the first network device.

[0255] As shown in Figure 11, the communication device 1100 includes a processing unit 1110 and a transceiver unit 1120. The communication device 1100 is configured to implement the functions of a terminal or base station in the embodiment of the method shown in Figure 6.

[0256] When the communication device 1100 is configured to implement the functions of the first network device in the embodiment of the method shown in Figure 6.

[0257] Transceiver unit 1120 is configured to receive a request message, which is used to request the creation of a first broadcast session for a first public land mobile network PLMN, the first broadcast session being a session for a first broadcast service, and processing unit 1110 is configured to determine, based on the request message, that the first broadcast session and the second broadcast session belong to the first broadcast service session, the second broadcast session being a session created for a second PLMN, and transceiver unit 1120 is configured to transmit first instruction information to a second network device, which instructs not to set up a first transmission channel for the first broadcast session, the first transmission channel being a channel for transmitting the first broadcast service.

[0258] In a possible design, the request message includes a first temporary multicast group identifier and a first broadcast service identifier, the first temporary multicast group identifier including a first PLMN identifier.

[0259] In a possible design, there is a second transmission channel set up for a second broadcast session before the first broadcast session is created, and this second transmission channel is the channel for transmitting the first broadcast service.

[0260] In a possible design, the transceiver unit 1120 is configured to send a second instruction to a third network device before sending a first instruction to a second network device, the second instruction instructing the third network device not to set up a first transmission channel for the first broadcast session.

[0261] In a possible design, the transceiver unit 1120 is configured to receive address information for a first transmission channel from a third network device, where the address information for the first transmission channel is null or an invalid value.

[0262] In a possible design, the transceiver unit 1120 is configured to transmit a third instruction to a third network device, which instructs the third network device not to set up a third transmission channel for a first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device.

[0263] In a possible design, the transceiver unit 1120 is configured to receive address information for a third transmission channel from a third network device in a unicast scenario, where the address information for the third transmission channel is null or invalid.

[0264] In a possible design, the transceiver unit 1120 is configured to transmit a fourth instruction to a first core network device, the fourth instruction instructing not to set up a third transmission channel for a first broadcast session, the third transmission channel being a channel for transmitting the first broadcast service to the first core network device.

[0265] In a possible design, the transceiver unit 1120 is configured to receive request messages from a first core network device.

[0266] In a possible design, the transceiver unit 1120 is configured to transmit a fifth instruction to a second network device, which instructs not to set up a third transmission channel for the first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device.

[0267] In a possible design, the transceiver unit 1120 is configured to receive request messages from a second network device.

[0268] For a more detailed description of the processing unit 1110 and the transceiver unit 1120, please refer to the relevant description in the embodiment of the method shown in Figure 6.

[0269] As shown in Figure 12, the communication device 1200 includes a processor 1210 and an interface circuit 1220. The processor 1210 and the interface circuit 1220 are connected to each other. It can be understood that the interface circuit 1220 may be a transceiver or an input / output interface. Optionally, the communication device 1200 may further include a memory 1230 configured to store instructions executed by the processor 1210, or input data required by the processor 1210 to execute an instruction, or data generated after the processor 1210 has executed an instruction.

[0270] When the communication device 1200 is configured to perform the method shown in Figure 12, the processor 1210 is configured to perform the functions of the processing unit 1110, and the interface circuit 1220 is configured to perform the functions of the transceiver unit 1120.

[0271] It can be understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be another general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable logic device, transistor logic device, hardware component, or any combination thereof. The general-purpose processor may be a microprocessor, or any conventional processor, etc.

[0272] The method steps in embodiments of the present invention may be implemented in hardware or by software instructions that can be executed by a processor. The software instructions may include corresponding software modules. The software modules may be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, removable hard disks, CD-ROMs, or any other form of storage medium known in the art. For example, the storage medium may be coupled to a processor, thereby enabling the processor to read information from and write information to the storage medium. Alternatively, the storage medium may be a component of the processor. The processor and storage medium may be located within an ASIC. In addition, the ASIC may be located in a base station or terminal. Alternatively, the processor and storage medium may exist as discrete components in a base station or terminal.

[0273] All or part of the embodiments described above may be implemented by software, hardware, firmware, or any combination thereof. When software is used to implement an embodiment, all or part of the embodiment may be implemented in the form of a computer program product. A computer program product includes one or more computer programs or instructions. When a computer program or instruction is loaded onto a computer and executed, all or part of the procedures or functions in the embodiments of the present application are performed. The computer may be a general-purpose computer, a dedicated computer, a computer network, a network device, a user device, or other programmable device. The computer program or instruction may be stored on a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer program or instruction may be transmitted by wire or wirelessly from one website, computer, server, or data center to another website, computer, server, or data center. The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device that integrates one or more available media, such as a server or data center. The usable media may be magnetic media, such as floppy disks, hard disks, or magnetic tapes; optical media, such as digital video discs; or semiconductor media, such as solid-state drives. The computer-readable storage medium may be volatile or non-volatile, or may include both types of storage media, such as volatile and non-volatile.

[0274] In each embodiment of the present application, unless otherwise specified or there is no logical conflict, terms and / or descriptions in different embodiments are consistent and can be referenced to one another, and technical features in different embodiments can be combined on the basis of their internal logical relationships to form new embodiments.

[0275] It should be understood that the various numbers in the embodiments of this application are used merely for distinction to facilitate explanation and are not used to limit the scope of the embodiments of this application. The sequence numbers of the processes described above do not imply an execution order, and the execution order of the processes should be determined based on the function and internal logic of the processes.

Claims

1. A communication method, wherein the method is A first network device receives a request message, the request message being used to request the creation of a first broadcast session for a first public land mobile network (PLMN), the first broadcast session being a session for a first broadcast service, and the steps are: The first network device determines, based on the request message, that the first broadcast session and the second broadcast session belong to the session of the first broadcast service, wherein the second broadcast session is a session created for the second PLMN. The steps include: transmitting first instruction information to a second network device via the first network device, wherein the first instruction information instructs not to set up a first transmission channel for the first broadcast session, and the first transmission channel is a channel for transmitting the first broadcast service; Methods that include...

2. The method according to claim 1, wherein the request message includes a first temporary multicast group identifier and a first broadcast service identifier, and the first temporary multicast group identifier includes a first PLMN identifier.

3. The method according to claim 1 or 2, wherein, prior to the creation of the first broadcast session, there is a second transmission channel set up for the second broadcast session, the second transmission channel being a channel for transmitting the first broadcast service.

4. Before the first network device transmits the first instruction information to the second network device, the method: The first network device transmits a second instruction to a third network device, the second instruction instructing the third network device not to set up the first transmission channel for the first broadcast session, further comprising the step of transmitting a second instruction to a third network device by the first network device, The method according to any one of claims 1 to 3.

5. The first network device receives address information for the first transmission channel from the third network device, further comprising the step of the first network device receiving address information for the first transmission channel, wherein the address information for the first transmission channel is null or an invalid value. The method according to claim 4.

6. The first network device transmits a third instruction to the third network device, the third instruction being an instruction to the third network device not to set up a third transmission channel for the first broadcast session, the third transmission channel being a channel for transmitting the first broadcast service to the first core network device, further comprising the steps of: The method according to any one of claims 1 to 5.

7. In a unicast scenario, the first network device receives address information for the third transmission channel from the third network device, the address information for the third transmission channel being null or invalid, further comprising the steps: The method according to claim 6.

8. The method according to claim 6, further comprising the step of the third network device skipping joining a multicast group in a multicast scenario.

9. The first network device transmits a fourth instruction to the first core network device, the fourth instruction instructing not to set up the third transmission channel for the first broadcast session, the third transmission channel being the channel for transmitting the first broadcast service to the first core network device, further comprising the steps of: The method according to any one of claims 1 to 7.

10. The step of receiving the request message by the first network device is: The first network device includes the step of receiving the request message from the first core network device, The method according to any one of claims 1 to 9.

11. The method according to any one of claims 1 to 10, wherein the first network device is a centralized unit CU or a centralized unit control plane CU-CP, and the second network device is a distributed unit DU.

12. The first network device transmits a fifth instruction to the second network device, the fifth instruction instructing that a third transmission channel not be set up for the first broadcast session, the third transmission channel being a channel for transmitting the first broadcast service to the first core network device, further comprising the step of transmitting a fifth instruction to the second network device, the first network device transmits a fifth instruction to the second network device, the first network device transmits a fifth instruction to the second network device, the first network device transmits a fifth instruction to the second network device, the second network device transmits a fifth instruction to the second network device, the first network device transmits a fifth instruction to the second network device, the first network device transmits a fifth instruction to the second network device, the second network device transmits a third transmission channel for the first broadcast session, the third transmission channel is a channel for transmitting the first broadcast service to the first core network device, the first network device transmits a fifth instruction to the second network device, the first network device transmits a fifth instruction to the second network device, the first network device transmits a fifth instruction to the second network device, the third transmission channel is a channel for transmitting the first broadcast service to the first core network device, the first network device transmits a fifth instruction to the second network device, the first network device transmits a fifth instruction to the second network device, the third transmission channel is a channel for transmitting the first broadcast service to the first core network device, the first network device transmits a fifth instruction to the first network device, the first network device transmits a fifth instruction to the first network device, the third transmission channel is a channel for transmitting the first broadcast service to the first core network device, the first network device transmits a fifth instruction to the first network device, the first network device transmits a fifth instruction to the first network device, the first network device transmits a third transmission channel for the first broadcast session, the first network device transmits a first broadcast service to the first core network device The method according to any one of claims 1 to 3.

13. After the first network device transmits the first instruction information to the second network device, the method proceeds as follows: The second network device transmits a sixth instruction to a third network device, the sixth instruction instructing the third network device to release the first transmission channel, further comprising the steps of: The method according to any one of claims 1 to 3 and 12.

14. The step of receiving the request message by the first network device is: The first network device includes the step of receiving the request message from the second network device, The method according to any one of claims 1 to 3, 12, and 13.

15. The method according to any one of claims 1 to 3, 10, 11, and 12, wherein the first network device is a DU and the second network device is a CU-CP or a CU.

16. The method according to any one of claims 1 to 15, wherein the first network device provides services to the first PLMN and the second PLMN.

17. A communication device, wherein the device is a first network device or a chip within the first network device, and the device includes a transceiver unit and a processing unit. The transceiver unit is configured to receive a request message, which is used to request the creation of a first broadcast session for a first public land mobile network (PLMN), the first broadcast session being a session for a first broadcast service. The processing unit is configured to determine, based on the request message, that the first broadcast session and the second broadcast session belong to the session of the first broadcast service, and the second broadcast session is a session created for the second PLMN. The transceiver unit is configured to transmit a first instruction to a second network device, the first instruction instructing not to set up a first transmission channel for the first broadcast session, and the first transmission channel is a channel for transmitting the first broadcast service. Device.

18. The apparatus according to claim 17, wherein the request message includes a first temporary multicast group identifier and a first broadcast service identifier, and the first temporary multicast group identifier includes a first PLMN identifier.

19. The apparatus according to claim 17 or 18, wherein, prior to the creation of the first broadcast session, there is a second transmission channel set up for the second broadcast session, the second transmission channel being a channel for transmitting the first broadcast service.

20. The apparatus according to any one of claims 17 to 19, wherein the transceiver unit is configured to transmit a second instruction to a third network device before transmitting the first instruction to the second network device, the second instruction instructing the third network device not to set up the first transmission channel for the first broadcast session.

21. The apparatus according to claim 20, wherein the transceiver unit is configured to receive address information of the first transmission channel from the third network device, and the address information of the first transmission channel is null or an invalid value.

22. The apparatus according to any one of claims 17 to 21, wherein the transceiver unit is configured to transmit a third instruction information to the third network device, the third instruction information instructing the third network device not to set up a third transmission channel for the first broadcast session, and the third transmission channel is a channel for transmitting the first broadcast service to the first core network device.

23. The apparatus according to claim 22, wherein the transceiver unit is configured to receive address information of the third transmission channel from the third network device in a unicast scenario, and the address information of the third transmission channel is null or an invalid value.

24. The apparatus according to any one of claims 17 to 23, wherein the transceiver unit is configured to transmit a fourth instruction information to the first core network device, the fourth instruction information instructing not to set up the third transmission channel for the first broadcast session, the third transmission channel being the channel for transmitting the first broadcast service to the first core network device.

25. The apparatus according to any one of claims 17 to 24, wherein the transceiver unit is configured to receive the request message from the first core network device when it receives the request message.

26. The apparatus according to any one of claims 17 to 19, wherein the transceiver unit is configured to transmit a fifth instruction information to the second network device, the fifth instruction information instructing not to set up a third transmission channel for the first broadcast session, the third transmission channel being a channel for transmitting the first broadcast service to the first core network device.

27. The apparatus according to any one of claims 17 to 19 and 26, wherein the transceiver unit is configured to receive the request message from the second network device when it receives the request message.

28. A chip coupled to a memory, which reads a computer program stored in the memory and performs the method according to any one of claims 1 to 16.

29. A computer-readable storage medium, wherein the storage medium stores a computer program or instruction, and when the computer program or instruction is executed by a communication device, the method according to any one of claims 1 to 16 is performed.

30. A communication device comprising a processor and an interface circuit, wherein the interface circuit is configured to receive signals from other communication devices and transmit signals to the processor or transmit signals from the processor to other communication devices, and the processor is configured to carry out the method according to any one of claims 1 to 16 via logic circuits or by executing code instructions.

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