Multicast broadcast service tunnel processing

Abstract

A method for a second network node is provided, the method comprising: receiving a message from a first network node configured to provide a multicast broadcast service MBS to a user equipment UE, the message comprising an MBS identifier identifying the MBS and at least one data flow identifier corresponding to at least one data flow to be offloaded from the first network node to the second network node for providing the MBS; determining whether a tunnel associated with the MBS identifier exists between the second network node and a user plane entity; based on the determination, sending a response message to the first network node indicating whether to request to establish a new tunnel for the MBS; and using an existing tunnel or the new tunnel requested to be established for providing the MBS.

Description

Technical Field

[0001] The following exemplary embodiments relate to communications. Background Art

[0002] Modern wireless communication networks provide different kinds of services to User Equipments (UEs). It may be beneficial to develop solutions that aim to enhance the effectiveness of such services. One example of such a service may be a Multicast Broadcast Service (MBS). Summary of the invention

[0003] According to an aspect, the subject matter of the independent claims is provided. Some embodiments are defined in the dependent claims.

[0004] According to an aspect, there is provided a computer program comprising instructions for causing an apparatus to perform a method according to any one of claims 16 to 30.

[0005] Embodiments that do not fall within the scope of the claims are to be construed as examples useful for understanding the present disclosure.

[0006] One or more implementation examples are set forth in further detail in the drawings and the following description. Other features will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Some embodiments will be described below with reference to the accompanying drawings, in which:

[0008] Figure 1A An example of a wireless communication system to which embodiments may be applied is shown;

[0009] Figure 1B and Figure 1C Some example wireless communication system architectures are shown to which embodiments may be applied;

[0010] Figure 2 and Figure 3 A schematic diagram of a process according to some embodiments is shown;

[0011] Figure 4A , Figure 4B , Figure 4C and Figure 5 shows a signal schematic diagram according to some embodiments; and

[0012] Figure 6 and Figure 7 An apparatus according to some embodiments is shown. DETAILED DESCRIPTION

[0013] The following embodiments are some examples. Although the specification may refer to "one", "an" or "some" embodiments in several places, this does not mean that such reference refers to the same embodiment or that the feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments. In addition, the words "comprises" and "comprising" should be understood as not limiting the described embodiments to consist only of those features that have been mentioned, and such embodiments may also include features / structures, etc. that are not specifically mentioned.

[0014] In the following, different exemplary embodiments will be described using a radio access architecture based on Advanced Long Term Evolution (Advanced LTE, LTE-A) or New Radio (NR, 5G) as an example of an access architecture to which the embodiments may be applied, but the embodiments are not limited to such architectures. Those skilled in the art will recognize that these embodiments may also be applied to other types of communication networks with suitable components by appropriately adjusting the parameters and procedures. Some examples of other options for suitable systems are Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE), Wireless Local Area Network (WLAN or WiFi), Worldwide Interoperability for Microwave Access (WiMAX), Personal Communications Service (PCS), Wideband Code Division Multiple Access (WCDMA), systems using Ultra-Wideband (UWB) technology, sensor networks, Mobile Ad Hoc Networks (MANETs), and Internet Protocol Multimedia Subsystem (IMS), or any combination thereof.

[0015] FIG1 depicts an example of a simplified system architecture, which shows some units and functional entities, the implementation of which may differ from that shown. The connections shown in FIG1 are logical connections; the actual physical connections may be different. It is obvious to those skilled in the art that the system typically includes other functions and structures in addition to those shown in FIG1.

[0016] However, the embodiments are not limited to the systems given as examples, but a person skilled in the art may apply the solutions to other communication systems equipped with the necessary characteristics.

[0017] Figure 1A The example of FIG. 1 shows a portion of an exemplary radio access network. Figure 1ATerminal devices or user equipment 100 and 102 are shown, which are configured to be wirelessly connected to an access node (such as (e / g)NodeB) 104 providing the cell on one or more communication channels in the cell. (e / g)NodeB refers to eNodeB or gNodeB as defined in the 3GPP specification. The physical link from the user equipment to the (e / g)Node B is called an uplink or reverse link, and the physical link from the (e / g)NodeB to the user equipment is called a downlink or forward link. It should be understood that the (e / g)Node B or its functions can be implemented by using any node, host, server or access point entity suitable for such purpose.

[0018] The communication system usually includes more than one (e / g) Node B, in which case the (e / g) Node B can also be configured to communicate with each other on a wired or wireless link designed for this purpose. These links can be used for signaling purposes, but can also be used to route data from one (e / g) Node B to another (e / g) Node B. (e / g) Node B is a computing device configured to control the radio resources of the communication system to which it is coupled. Node B can also be referred to as a base station, access point, access node or any other type of interface device, including a relay station capable of operating in a wireless environment. (e / g) Node B includes or is coupled to a transceiver. The connection provided from the transceiver of the (e / g) Node B to the antenna unit establishes a two-way radio link with the user equipment. The antenna unit may include multiple antennas or antenna elements. (e / g) Node B is further connected to a core network 110 (CN or next generation core NGC). Depending on the system, the corresponding part on the CN side can be a serving gateway (S-GW, routing and forwarding user data packets), a packet data network gateway (P-GW) for providing a connection between the user equipment (UE) and an external packet data network, or a mobility management entity (MME), etc.

[0019] User equipment (also referred to as UE, user device, user terminal, terminal device, etc.) shows a type of device to which resources on the air interface are allocated and assigned, and therefore, any features described herein with respect to user equipment can be implemented with corresponding devices (such as relay nodes). An example of such a relay node is a layer 3 relay (self-backhaul relay) toward a base station.

[0020] User equipment generally refers to a portable computing device including a wireless mobile communication device that operates with or without a subscriber identity module (SIM), including but not limited to the following types of devices: mobile stations (mobile phones), smart phones, personal digital assistants (PDAs), mobile phones, devices using wireless modems (alarms or measuring devices, etc.), laptop and / or touch screen computers, tablet computers, game consoles, notebook computers, and multimedia devices. It should be understood that user equipment can also be an almost exclusive uplink device, an example of which is a camera or video camera that uploads images or video clips to a network. User equipment can also be a device with the ability to operate in an Internet of Things (IoT) network (such as an Industrial Internet of Things (IIoT) network), which is a scenario in which an object is provided with the ability to transmit data over a network without human-to-human or human-to-computer interaction. User equipment can also utilize the cloud. In some applications, a user device may include a small portable device (such as a watch, headset, or glasses) with a radio portion, and the calculation is performed in the cloud. A user device (or in some embodiments, a layer 3 relay node) is configured to perform one or more user equipment functions. User equipment may also be referred to as a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, or a user equipment (UE), to name just a few names or devices. User equipment may also refer to a vehicle implementation, such as a vehicle UE, in this document. Such UEs may be included in a vehicle and / or communicatively coupled to a vehicle so that they may be understood as part of one or more vehicles.

[0021] The various techniques described herein can also be applied to cyber-physical systems (CPS) (systems where cooperating computing elements control physical entities). CPS can enable the implementation and utilization of a large number of interconnected ICT devices (sensors, actuators, processors microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber-physical systems (where the physical system in question has inherent mobility) are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robots and electronic devices transported by humans or animals.

[0022] Furthermore, although the apparatus has been described as a single entity, different units, processors and / or memory units may be implemented (not necessarily in Figure 1A ).

[0023] 5G enables the use of multiple-input multiple-output (MIMO) antennas, many more base stations or nodes than LTE (the so-called small cell concept), including macro sites that operate in collaboration with small base stations and use various radio technologies depending on service requirements, use cases and / or available spectrum. 5G mobile communications support a wide range of use cases and related applications, including video streaming, augmented reality, different ways of sharing data and various forms of machine-type applications (such as (massive) machine-type communications (mMTC)), including vehicle safety, different sensors and real-time control. It is expected that 5G will have multiple radio interfaces, namely, below 6 GHz, cmWave and mmWave, and may also be able to integrate with existing traditional radio access technologies (such as LTE). Integration with LTE can be implemented, at least in the early stages, as a system in which macro coverage is provided by LTE and 5G radio interface access comes from small cells aggregated to LTE. In other words, 5G plans to support inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as below 6 GHz) – cmWave, sub-6GHz – cmWave – One of the concepts considered for use in 5G networks is network slicing, in which multiple independent and dedicated virtual subnetworks (network instances) can be created within essentially the same infrastructure to run services with different requirements for latency, reliability, throughput, and mobility.

[0024] The current architecture in LTE networks is completely distributed in the radio and is usually completely concentrated in the core network. Low-latency applications and services in 5G may need to bring content close to the radio, which leads to local bursts and multi-access edge computing (MEC). 5G enables analysis and knowledge generation to occur at the source of the data. This method may require the use of resources that may not be continuously connected to the network, such as laptops, smart phones, tablet computers and sensors. MEC provides a distributed computing environment for application and service hosting. It can also store and process content close to cellular subscribers to speed up response time. Edge computing covers a wide range of technologies, such as wireless sensor networks, mobile data collection, mobile signature analysis, collaborative distributed peer-to-peer self-organizing networking and processing, and can also be classified as local cloud / fog computing and grid / grid computing, dew computing, mobile edge computing, micro-cloud, distributed data storage and retrieval, autonomous self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (large-scale connection and / or latency critical), critical communications (autonomous driving cars, traffic safety, real-time analysis, time-critical control, healthcare applications).

[0025] The communication system may also be able to communicate with other networks, such as the public switched telephone network or the Internet 112, or use services provided by them. The communication network may also be able to support the use of cloud services, for example, at least a portion of the core network operations may be performed as a cloud service (this is in the Figure 1A 114). The communication system may also include a central control entity or the like, providing facilities for networks of different operators to collaborate, for example in spectrum sharing.

[0026] By using network function virtualization (NVF) and software defined networking (SDN), edge cloud can be introduced into the radio access network (RAN). Using edge cloud can mean that access node operations will be performed at least partially in a server, host or node operably coupled to a remote radio head or a base station including a radio part. Node operations can also be distributed among multiple servers, nodes or hosts. Applying cloud RAN architecture enables RAN real-time functions to be performed on the RAN side (in distributed units DU 104), while non-real-time functions are performed in a centralized manner (in centralized units CU 108).

[0027] It should also be understood that the functional allocation between core network operations and base station operations may be different from LTE, or even non-existent. Some other technological advances that can be used are big data and all-IP, which may change the way networks are built and managed. 5G (or New Radio NR) networks are designed to support multiple hierarchical structures, where MEC servers can be placed between the core and the base station or Node B (gNB). It should be understood that MEC can also be applied in 4G networks.

[0028] 5G can also use satellite communications to enhance or supplement the coverage of 5G services, for example by providing backhaul. Possible use cases are to provide service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or for passengers in vehicles, or to ensure service availability for critical communications and future railway, maritime and / or aviation communications. Satellite communications can use geostationary orbit (GEO) satellite systems, but can also utilize low Earth orbit (LEO) satellite systems, in particular mega-constellations (systems in which hundreds of (nano) satellites are deployed). Satellites 106 in a mega-constellation can cover several satellite-supported network entities that create ground cells. Ground cells can be created by ground relay nodes 104 or by gNBs located on the ground or in satellites.

[0029] It will be apparent to a person skilled in the art that the depicted system is an example of a part of a radio access system, and in practice the system may include multiple (e / g)Node Bs, a user equipment may access multiple radio cells and the system may also include other devices such as physical layer relay nodes or other network elements. At least one of the (e / g)Node Bs may be a home (e / g)Node B. In addition, in a geographical area of ​​the radio communication system, a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. A radio cell may be a macro cell (or umbrella cell, which is typically a large cell with a diameter of up to tens of kilometers), or a smaller cell, such as a micro cell, a femto cell or a pico cell. Figure 1A The (e / g)Node B of a cell can provide any type of these cells. A cellular radio system can be implemented as a multi-layer network including several types of cells. Typically, in a multi-layer network, one access node provides one or more cells of one type, and therefore multiple (e / g)Node Bs may be required to provide this network structure.

[0030] In order to meet the need to improve the deployment and performance of communication systems, the concept of "plug and play" (e / g) NodeB has been introduced. Generally, in addition to the home (e / g) Node B (H(e / g) Node B), a network that can use "plug and play" (e / g) Node B also includes a home Node B gateway or HNB-GW ( Figure 1A (not shown). The HNB gateway (HNB-GW) usually installed in the operator's network can aggregate services from a large number of HNBs back to the core network. The network discussed in this article may refer to a cellular network such as 5G, etc.

[0031] like Figure 1A As indicated by the arrows in , UE 100, 102 (and / or any other UE of the described system) may support device-to-device (D2D) communication. D2D communication may sometimes be referred to as side-link communication.

[0032] One of the development goals in NR is one or more multicast broadcast services (MBS). MBS may include one or both of multicast transmission and broadcast transmission. MBS service may be provided to UE by network node 104 as point-to-point (PtP) or point-to-multi-point (PtM) transmission, for example. The former may sometimes be referred to as unicast transmission and the latter may sometimes be referred to as multicast transmission. In addition, MBS may be provided to UE in a dual connectivity (DC) scenario, wherein one UE may be connected to two or more network nodes that provide one or more services to the UE. For example, in DC there may be a primary network node, referred to as primary node (MN) for short, and a secondary network node, referred to as secondary node (SN) for short, controlled by the primary network node (or some other entity), wherein the MN and the SN work together to provide MBS to the UE. The MN and the SN may be connected as described above. Figure 1A The MN and SN may be connected to the UE and provide substantially the same or different services to the UE. The MBS may also be sometimes referred to as a 5MBS. In particular, such terminology may be used for an MBS provided, for example, in a 5G or NR system.

[0033] Figure 1B and Figure 1C Some examples of wireless communication system architectures to which embodiments may be applied are illustrated. SDAP may refer to Service Data Adaptation Protocol, PDCP may refer to Packet Data Convergence Protocol, RLC may refer to Radio Link Control, MAC may refer to Media Access Control, and PHY may refer to Physical Layer. S may indicate the location in the protocol stack where data replication and forwarding (i.e., switching) occurs. Data flow is depicted with arrows, showing the direction of data flow from SDAP to PHY in different protocol layers.

[0034] refer to Figure 1B , depicts a Layer 2 (L2) architecture alternative 1 that uses DRBs for PtP transmissions and SC-MRBs for PtM transmissions. The network may configure a DRB for at least one UE in a multicast group and one SC-MBR for the multicast group (ie, per session).

[0035] refer to Figure 1C, depicts L2 architecture alternative 2 which uses SC-MRB for both PtP and PtM transmissions in a split bearer scenario, i.e., PDCP PDUs may be sent in either the PtP branch or in the PtM branch of the bearer. At least one branch of the SC-MRB bearer may have its own RLC entity. It should be noted that with respect to the F1-U interface, L2 architecture alternative 1 may use an F1-U tunnel for at least one radio bearer, i.e., at least one DRB and for at least one SC-MRB. In case of L2 architecture alternative 2, if the data replication and forwarding functionality is located in the DU, one shared F1-U tunnel may be used.

[0036] It should be noted that Figure 1B and Figure 1C The example architectures of should be understood as examples, and other types of architectures to which embodiments may be applied may be used.

[0037] Therefore, in general, MBS can be provided to UEs in DC scenarios. For example, a UE using a certain MBS can be served by a MN. There may be situations where it is beneficial for a service node to be changed to a SN. Therefore, it may be beneficial to further develop solutions that enhance dynamic switching of service nodes for providing MBS to one or more UEs. Switching may occur, for example, between PtP transmission and PtM transmission.

[0038] Figure 2 FIG. 1 illustrates a flow chart according to an embodiment. Figure 2 , a method for a second network node of a wireless communication network is provided, the method comprising: receiving a message from a first network node configured to provide an MBS to a UE, the message comprising an MBS identifier identifying the MBS and at least one data flow identifier corresponding to at least one data flow to be offloaded from the first network node to the second network node for providing the MBS (box 202); determining whether a tunnel associated with the MBS identifier exists between the second network node and a user plane entity (box 204); based on the determination, sending a response message to the first network node indicating whether to request to establish a new tunnel for the MBS (box 206); and using an existing tunnel or the new tunnel requested to be established for providing the MBS (box 208).

[0039] Figure 3 FIG. 1 illustrates a flow chart according to an embodiment. Figure 3, a method for a first network node of a wireless communication network is provided, the method comprising: determining to offload at least one data flow for providing an MBS to a second network node, wherein the MBS is provided to a UE (box 302); sending a message to the second network node, the message comprising an MBS identifier identifying the MBS and at least one data flow identifier corresponding to at least one data flow to be offloaded from the first network node to the second network node (box 304); receiving a response message from the second network node indicating whether to request to establish a new tunnel between the second network node and a user plane entity for providing the MBS (box 306); and if the establishment of the new tunnel is requested, initiating the establishment of the new tunnel (box 308).

[0040] Figure 2 and Figure 3 The method described in can be applied, for example, to Figure 1A system (i.e., a wireless communication network), and can be applied, for example, to Figure 1B and Figure 1C The architecture depicted in . Figure 2 and Figure 3 The UE in question may be, for example, UE 100 or UE 102, or some other similar network device. Figure 2 and Figure 3 The network node discussed may refer to the network node 104, or for example the CN 110 / CU 108, or some other network element configured to perform the described method steps. Specifically, in some example embodiments, the first network node may refer to the MN and the second network node may refer to the SN. For example, in the case where a service node (e.g., a first network node) determines to offload an MBS data flow (sometimes referred to as a business flow or an MBS service flow) to another node (e.g., a second network node), the described solution may enable switching from PtP to PtM when providing MBS.

[0041] refer to Figure 2 and Figure 3 The described tunnel may be a tunnel that enables MBS data to be transferred from a user plane core network node (e.g., a user plane function (UPF)) to a network node (e.g., a radio network node). That is, a tunnel for a specific MBS having a specific identifier (i.e., an MBS identifier) ​​may be established between a user plane core network node (e.g., a UPF) and a network node that provides the MBS to the UE. For example, a second network node and the UPF may be connected via a tunnel for the MBS. Such a tunnel may sometimes be referred to as an N3 tunnel. In a sense, it may be understood that the MBS may be provided to the second network node via the described tunnel, and the second network node may provide the MBS to one or more UEs. The target of the MBS may be, for example, one or more UEs.

[0042] An identifier that identifies an MBS may sometimes be referred to as an MBS identifier. A data stream identifier may correspond to (i.e., identify) a data stream. Thus, if more than one data stream exists or is used to provide an MBS, there may be a data stream identifier for identifying a member of at least one data stream. Sometimes, a data stream may be described as a quality of service (QoS) stream identified by a QoS stream indicator (QFI). A QFI may identify (or correspond to) a QoS stream. For example, if two MBS QoS streams (i.e., QoS streams for MBS) are used, a first QFI may be associated with a first QoS stream and a second QFI may be associated with a second QoS stream. In this example, both the first QoS stream and the second QoS stream may be used to provide an MBS identified by an MBS identifier (or simply an identifier). One or more QoS streams may be used to provide a given MBS to one or more UEs. One or more QoS streams may use an existing or established tunnel (e.g., an N3 tunnel).

[0043] According to an embodiment, at least one data flow described herein includes and / or is at least one QoS flow.

[0044] As indicated in block 208, an existing tunnel or a new tunnel (i.e., requested to be established in block 206) may be used to provide MBS to, for example, one or more UEs. Thus, if or when it is determined (i.e., block 204) that a tunnel does exist, an existing tunnel may be used to provide MBS. However, if or when it is determined (i.e., block 204) that a tunnel does not exist, a new tunnel may be requested to be established (block 206) and used (block 208) for providing MBS. Tunnel establishment may occur after the request is sent to the first network node. The first network node may then send a tunnel creation request message to a session management function (SMF).

[0045] The proposed solution enables the use of substantially the same tunnel for providing MBS to multiple UEs. For example, if three UEs receive substantially the same MBS service, the MBS data may not need to be copied three times on the tunnel, but rather sent once between the UPF and the network node. Multiple tunnels may exist for a given node, for example, one tunnel for at least one MBS provided to the UE. For example, if a first network node provides MBS to UE 100, it may have a tunnel to the UPF in order to receive and / or send applicable data streams. For example, when providing substantially the same MBS to UE 102, the first network node may use substantially the same tunnel. In the first example, the first network node may provide PtP transmission to UE 100, and in the latter example, PtM ​​to UE 100 and 102. Similarly, as presented in the method proposed above, the second network node may use an existing tunnel to provide MBS to multiple UEs (e.g., two or more UEs). Alternatively, if a tunnel does not exist, a tunnel may be created, which is then used to provide MBS to at least one UE (i.e., if necessary, it may then be provided to more than one UE). For example, if a tunnel for a particular MBS exists, the transfer from a UE served by a MN to a UE served by a SN can be smooth. It should also be noted that the MN does not have to know that the SN already has a tunnel for the offloaded MBS. That is, the SN can provide the UE with an MBS offloaded from a different MN to the SN.

[0046] In an embodiment, the second network node provides a primary secondary cell (PSCell). In an embodiment, the second network node is in PtP mode. However, the second network node may change the mode to PtM.

[0047] Let us refer to some embodiments of the FIG. 4A to FIG. 4C Let us first refer to an embodiment in which there is no tunnel for MBS between UPF 430 and second network node 420 when second network node 420 receives request message 452. Figure 4A That is, the second network node 420 may not provide MBS to one or more UEs at this time. Therefore, in block 452, the first network node 452 may send the request message to the second network node 420. The request message may be related to Figure 2 and Figure 3The messages described (blocks 202 and 304) are similar. The message may indicate that an MBS (or specifically, one or more data flows of an MBS) is to be offloaded from the first network node 410 to the second network node 420, and further indicate the MBS to be offloaded. Thus, the first network node may indicate in the message that the offloaded data flow is for an MBS. Thus, the message may be sent by the first network node 410 after and / or in response to determining that the MBS should be offloaded to the second network node 420. The first network node 410 may determine to offload the MBS, for example, based on the load at the first network node exceeding a threshold or the second network node 420 having excess capacity. Sending the request message in block 452 may be included in a DC bearer setup, wherein the first network node 410 establishes a DC bearer in a radio cell provided by the second network node 420. The first network node 410 may inform the second network node 420 that the offloaded QoS flow is for MBS unicast, and it provides the corresponding MBS ID (e.g., Mcast ID=1) to the second network node 420. This may enable the second network node 420 to identify that the QoS flow is for a given MBS service and detect whether a tunnel for that service already exists.

[0048] In an embodiment, the request message includes an identifier that identifies the MBS (e.g., an MBS identifier). For example, for a given MBS (e.g., MBS service 1), this may mean Mcast ID=1. An MBS service may include one or more data streams, which may sometimes be referred to as quality of service (QoS) streams and / or sent on quality of service (QoS) streams. A QoS stream may have a minimum level of granularity, based on which a 5G system may distinguish user data and provide differentiated treatment (i.e., quality of service). A QoS stream may be identified by a QoS stream ID (QFI) and may have an associated QoS profile. In some example embodiments, the message may include a list of data QoS streams and / or their associated profiles. The described message may be referred to as a request message because it may request the SN to start serving the UE with the indicated MBS. The request message may sometimes be referred to as an SN addition / modification request, or simply as such. Figure 2 and Figure 3 The message in question.

[0049] In block 454, the second network node 420 may determine that a new tunnel for the MBS is needed between the second network node 420 and the UPF 430. Specifically, a new tunnel may be needed to transfer one or more data flows of the MBS between the second network node 420 and the UPF 430. The determination may be based on detecting that there is no tunnel for the MBS between the node 420 and the UPF 430. For example, using the above-mentioned MBS identifier Mcast ID=1, the network node 420 may determine that it does not have a tunnel for Mcast ID=1.

[0050] In block 456, the second network node 420 may send a response message to the first network node. If it is determined in block 454 that a new tunnel is needed, the response message may indicate that a new tunnel is needed. In an embodiment, the response message is sent in response to determining whether a new tunnel for MBS is needed (e.g., in response to block 454).

[0051] In an embodiment, the response message of block 456 includes transport network layer information (TNLI) for establishing a new tunnel between the second network node 420 and the UPF 430. Thus, the TNLI may be used by the network to set up the new tunnel. The TNLI may include information about the tunnel to be established (e.g., an N3 tunnel). For example, the TNLI may include an IP address of a tunnel endpoint and a tunnel endpoint identifier. The second network node 420 may allocate a new TNLI for the MBS (i.e., in the event that a tunnel for the offloaded MBS does not exist) and indicate the allocated TNLI to the first network node 410 in order to establish the new tunnel.

[0052] The response message may sometimes be referred to as an SN Addition / Modification Request Acknowledge message. In some embodiments, the message includes a list of MBS QoS flows that can be accepted by the second network node 420. In some embodiments, the message may indicate the accepted QoS flows (with their mapped DRBs) and include the TNLI for the tunnel to be established. Note that, for example, if architecture alternative 1 (see Figure 1B ), a DRB may be indicated. The accepted QoS flows may indicate substantially the same QoS flows or a subset of QoS flows requested to be offloaded to the second network node 420. In some cases, the requested subset of flows may be accepted by the second network node 420, and the remaining flows may be provided by the first network node 410 or offloaded to some other network node. However, even if at least one data flow configured for providing MBS (or simply referred to as MBS data flow) is accepted by the second network node 420, a tunnel between the second network node 420 and the UPF 430 may still be established.

[0053] In block 458, first network node 410 may initiate establishment of the requested new tunnel by sending a tunnel creation request to session management function (SMF) 440. In an embodiment, the tunnel creation request includes the TNLI received from second network node 420 via the response message sent in block 456. In some example embodiments, the tunnel creation request is a Protocol Data Unit (PDU) Session Modify Indication message.

[0054] In block 460, SMF 440 may request UPF 430 to create a tunnel with the received TNLI. The generation of tunnel 462 between second network node 420 and UPF 430 may include creating a bearer for the tunnel, as shown in block 460. The tunnel may be generated by UPF 430 according to the TNLI indicated by second network node 420 to first network node 410, reported from node 410 to SMF 440, and further reported from SMF 440 to UPF 430. The created tunnel 462 may be used to provide MBS to one or more UEs by second network node 420.

[0055] In block 464 , SMF 440 may confirm receipt of the tunnel creation request by UPF 430 and successful creation of the tunnel to first network node 410 by sending a response to tunnel creation request 458 .

[0056] Next, let us refer to some embodiments illustrating that a tunnel (block 470) for the offloaded MBS already exists when a request message is received (block 472). Figure 4B The request message of block 472 may be similar or substantially the same as that of block 452. That is, certain MBSs may be indicated in the message, wherein the MBSs may be offloaded to the second network node 420.

[0057] In block 474, second network node 420 may determine that a tunnel for the MBS to be offloaded already exists between node 420 and UPF 430. The tunnel may have been generated, for example, before receiving the request message in block 474. The tunnel may have been generated, for example, for providing MBS to some other UE based on a request message (e.g., similar to blocks 452 or 472) received from another network node (e.g., a third network node).

[0058] In block 476, the second network node 420 may send a response message to the first network node 410. The message may indicate that a tunnel for the MBS already exists. In other words, this may mean that the message indicates that no new tunnel is requested to be established.

[0059] In an embodiment, the response message of block 476 includes a TNLI corresponding to an existing tunnel for MBS and / or an additional indicator for indicating that no new tunnel for MBS is requested to be established. The additional indicator may be, for example, a flag such as a one-bit indicator. The TNLI may be understood, for example, as the TNLI of an existing tunnel. The additional indicator may sometimes be referred to simply as an indicator for indicating that no new tunnel for MBS is requested to be established. It may be used alone or together with the TNLI to indicate that a new tunnel is now required (e.g., a tunnel for the TNLI already exists). As described, it may not be necessary to indicate the TNLI, but it may be beneficial in some cases.

[0060] In an embodiment, the response message of block 476 is generated so that it does not include a TNLI regarding an existing tunnel. That is, the message may not include a TNLI, or at least not regarding an already existing tunnel (ie, tunnel 470).

[0061] The message of block 476 may sometimes be referred to as an SN add / modify request confirm message and may further include a list of MBS streams that may be accepted.

[0062] Based on the response message of block 476, the first network node 410 may determine that no new tunnel is needed to perform DC offloading of the MBS.

[0063] In an embodiment, the first network node 410 sends an indication indicating the TNLI and an additional indicator or no TNLI to the SMF 440 in block 478. However, this may not always be necessary in the described embodiments. Instead, the first network node 410 may not send the PDU session modification indication message because no new tunnel is to be established. In both cases, the SMF 440 may determine that no new tunnel is needed based on the indication sent or not sent, and therefore may not request the UPF 430 to open an additional tunnel for the second network node 420.

[0064] Thus, in an embodiment, the first network node 410 determines based on the response message (block 476) that a tunnel for MBS between the second network node and the user plane function already exists; and based on the determination, indicates to the SMF 440 that a tunnel for MBS between the second network node 420 and the user plane function 430 already exists. The indication may include sending the indication (e.g., see block 478) or it may be an implicit indication. That is, the first network node 410 may prevent the sending of a tunnel generation request to the SMF 440. Even if a PDU session modification indication message is to be sent, it may not be a tunnel generation request in the sense that it may not request the creation of a new tunnel. That is, in one example, the message may be sent without including the transport network layer information, as already discussed above. In another example, a message including the transport network layer information and an additional indicator (e.g., a flag) for indicating that a new tunnel for MBS is not requested to be established may be sent. That is, a tunnel for the indicated TNLI already exists. In another example, the message may be sent without including the transport network layer information but including an additional indicator (eg, a flag) for indicating that establishment of a new tunnel for MBS is not requested.

[0065] In an embodiment, determining by the first network node 410 that the tunnel exists is based on the response message comprising the TNLI about the tunnel and an additional indicator for indicating that establishment of a new tunnel for the MBS is not requested.

[0066] In an embodiment, determining by the first network node 410 that the tunnel exists is based on the response message not including the TNLI regarding the tunnel.

[0067] Figure 4C An embodiment is shown in the figure. Figure 4C In block 482, in response to determining that the first network node 410 no longer serves the UE for the given MBS and / or after determining that the first network node 410 no longer serves the UE for the given MBS, the first network node 410 may send a tunnel release request to the SMF 440. That is, for example, if after offloading the MBS to the second network node 420 (e.g. Figure 4A and Figure 4B), the first network node 410 no longer provides MBS to any UE, then the tunnel between the first network node 410 and the UPF 430 may no longer be needed. Therefore, the tunnel can be released. The release request may sometimes be referred to as a PDU session modification indication. The tunnel release request may include a TNLI associated with the tunnel to be released, that is, the TNLI may indicate the tunnel to be released. Based on the request, the SMF 440 may communicate with the UPF 430 to release the tunnel, for example by removing the bearer (box 484). The SMF 440 may further confirm the tunnel release request or at least the receipt of the request to the first network node 410 (box 486).

[0068] It should be noted that in Figure 4A and Figure 4B The request message sent in (blocks 452 and 472) may be sent by one or more MNs with respect to one or more UEs.

[0069] Now let us focus on Figure 5 , which illustrates an embodiment related to a case in which a UE is leaving an MBS or a cell provided by a second network node 420 that serves the UE with the MBS. That is, as shown in block 502, the second network node 420 may have a tunnel between the second network node 420 and the UPF 430 for providing MBS to at least two UEs. For simplicity, let us assume that there are two UEs (for which tunnels for MBS are established): UE1 and UE2.

[0070] The first network node may determine that it is necessary to release at least one data flow configured for providing an MBS to a served UE, for example based on an indication received from the SMF 440 in block 504. In this example, the UE may be UE1. The MBS to be released may be indicated in the message of block 504, for example, by using an MBS identifier of the MBS. In some embodiments, the message of block 504 is sent as a PDU Session Modify Request message. Thus, the message may request the second network node 420 to release the MBS bearer for UE1 (i.e., for a given MBS).

[0071] In block 506, the first network node 410 may send a release request to the second network node 420. The release request may indicate that at least one data flow configured for providing an MBS needs to be released. That is, the MBS service for UE1 needs to be released. The release request may, for example, use an MBS identifier to indicate the data flow to be released or only the MBS to be released.

[0072] The second network node 420 may receive a request from UE1 to release at least one data flow associated with the MBS ( ); and according to the request, release the at least one data flow (block 508 ).

[0073] However, in block 510, the second network node 420 may determine a need to continue using the tunnel 502 between the second network node 420 and the UPF 430 for providing MBS to at least one other UE. In this example, the UE may be UE2. This determination may be performed after releasing the MBS service.

[0074] Thus, in block 512, the second network node 420 may indicate to the first network node 410 the need to continue using the tunnel 502. The indication may, for example, include a TNLI enabling identification of the correct tunnel and / or a flag indicating that the tunnel continues to be required (ie, the existing tunnel should not be released).

[0075] The first network node 410 may receive the indication and further indicate the need to the SMF 440 (block 514). The indication may, for example, include a TNLI that enables identification of the correct tunnel and / or a flag indicating that the tunnel continues to be needed. Therefore, the SMF 440 may prevent requesting the UPF 430 to terminate or release the tunnel 502. Therefore, the UE2 may continue to be served by the second network node 420 with MBS. As described above, the indication of block 514 may include sending a message to the SMF, or it may be an implicit indication. For example, the first network node 410 may prevent sending a tunnel release request to the SMF 440. That is, the SMF 440 may be configured to operate so that it initiates the release of the tunnel in response to receiving an explicit message requesting release. Therefore, if such a message / request is not received, the SMF 440 may not release or terminate one or more tunnels.

[0076] Therefore, even if UE1 leaves the MBS service in the second network node 420, the second network node 420 may not release the tunnel and continue to use the tunnel to serve UE2.

[0077] According to one aspect, a method for a session management entity is provided, the method comprising: receiving a tunnel generation request from a first network node 410, the tunnel generation request not including a TNLI or including a TNLI and an additional indicator (flag) for indicating that establishment of a new tunnel for MBS is not requested; based on the request, determining that a tunnel for MBS between a user plane entity and a second network node 420 already exists; based on the determination, preventing establishment of a new tunnel between the initiating user plane entity and the second network node 420.

[0078] As used herein, SMF 440 may sometimes be referred to simply as a session management entity and UPF 430 may sometimes be referred to simply as a user plane entity.

[0079] Some benefits of the proposed solution may include at least:

[0080] When MBS is offloaded to a SN with DC (MBS ID=1), if the SN is already included in the requested MBS ID=1, the MN may not need to request the SMF to create a tunnel between the UPF and the SN. As referred to herein, this may mean that the SN has already provided MBS (with ID=1) to one or some other UEs. Of course, the ID may also be different from 1 used as an example in this article.

[0081] When MBS is offloaded back to MN (e.g. because UE is leaving MBS service 1), MN may not request SMF to release the tunnel between UPF and SN if SN is still involved in MBS service (i.e. still continues to provide MBS (ID=1) to one or some other UEs).

[0082] Figure 6 and Figure 7 An apparatus 600, 700 is provided, comprising a control circuit (CTRL) 610, 710 (such as at least one processor) and at least one memory 630, 730 including computer program code (software) 632, 732, wherein the at least one memory and the computer program code (software) 632, 732 are configured to cause the respective apparatus 600, 700 to perform together with the at least one processor Figures 1A to 5 Any embodiment or operation thereof.

[0083] refer to Figure 6 and Figure 7 The memory 630, 730 may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The memory 630, 730 may include a database 634, 734 for storing data.

[0084] The apparatus 600, 700 may further include a radio interface (TRX) 620, 720, which includes hardware and / or software for implementing a communication connection according to one or more communication protocols. The TRX may, for example, provide the apparatus with a communication capability to access a radio access network. The TRX may include standard well-known components such as amplifiers, filters, frequency converters, (de)modulators, encoder / decoder circuits, and one or more antennas. The TRX may, for example, provide access to the F1 and / or Xn interfaces, and / or provide UL / DL communication capabilities. In addition, the TRX may provide D2D capabilities for the UE. For example, the TRX may enable the use of tunnels for MBS, such as the N3 tunnel.

[0085] The apparatus 600, 700 may include a user interface 640, 740 including, for example, at least one keyboard, microphone, touch display, display, speaker, etc. The user interface 640, 740 may be used for a user of the apparatus 600, 700 to control the respective apparatus.

[0086] In an embodiment, the apparatus 600 may be a device that performs the above Figure 2 The second network node of the described method may be or be comprised therein. For example, the apparatus 600 may be or be comprised in the network node 104. The apparatus 600 may be or be comprised in the SN.

[0087] In an embodiment, the apparatus 700 may be a device that performs the above Figure 3 The first network node of the described method may be or be included therein. For example, the apparatus 700 may be or be included in the network node 104. The apparatus 700 may be or be included in the MN.

[0088] According to the embodiment, reference Figure 6 The control circuit 610 includes: a receiving circuit 612, which is at least configured to execute Figure 2 The operation described in block 202 of the embodiment; determining circuit 614, which is configured at least to perform Figure 2 The operations described in block 204 of FIG. 1; the transmitting circuit 616 is configured at least to perform the Figure 2 and using circuit 618, which is configured at least to perform the operation described in block 206 of Figure 2 The operations described in block 208 of FIG.

[0089] According to the embodiment, reference Figure 7 The control circuit 710 includes: a determination circuit 712, which is at least configured to execute Figure 3 The operation described in block 302 of FIG. 1; the transmitting circuit 714 is configured at least to perform the Figure 3The operations described in block 304 of the embodiment; receiving circuit 716, which is configured at least to perform Figure 3 The operations described in block 306 of the present invention; and initiating circuit 718, which is configured at least to perform the Figure 3 The operations described in block 308 of .

[0090] In an embodiment, at least some of the functions of the apparatus 600, 700 may be shared between two physically separated devices, thereby constituting an operating entity. Thus, the apparatus 600, 700 may be viewed as depicting an operating entity comprising one or more physically separated devices for performing at least some of the described processes. Thus, the apparatus 600, 700 using such a shared architecture may, for example, include a remote control unit (RCU), such as a host computer or a server computer, which is operably coupled (e.g., via a wireless or wired network) to a remote radio head (RRH) located in a base station or network node 104. In an embodiment, at least some of the described processes may be performed by the RCU. In an embodiment, the execution of at least some of the described processes may be shared between the RRH and the RCU. For example, CU / DU segmentation may use such a shared architecture.

[0091] In an embodiment, the RCU may generate a virtual network through which the RCU communicates with the RRH. In general, virtual networking may involve the process of combining hardware and software network resources and network functions into a single, software-based management entity (virtual network). Network virtualization may involve platform virtualization, which is often combined with resource virtualization. Network virtualization can be classified as external virtual networking, which combines many networks or parts of networks into a server computer or host computer (i.e., RCU). External network virtualization is intended to optimize network sharing. Another category is internal virtual networking, which provides class network functions to software containers on a single system.

[0092] In an embodiment, the virtual network may provide a flexible distribution of operations between the RRH and the RCU.In fact, any digital signal processing task may be performed in either the RRH or the RCU, and the boundaries where responsibilities are transferred between the RRH and the RCU may be chosen depending on the implementation.

[0093] According to an aspect, a system is provided comprising one or more apparatuses 600 and one or more apparatuses 700. In an embodiment, the system further comprises one or more UEs. In an embodiment, the system further comprises an SMF and a UPF.

[0094] As used in this application, the term "circuit" may refer to the following: (a) a hardware circuit implementation, such as an implementation using analog and / or digital circuits; and (b) a combination of circuits and software (and / or firmware), such as (if applicable): a combination of (i) a processor; or (ii) a portion of a processor / software, including a digital signal processor, software, and memory, which work together to enable the device to perform various functions; and (c) a circuit, such as a microprocessor or a portion of a microprocessor, which uses software or firmware to work, even if the software or firmware is not physically present. This definition of "circuit" applies to all uses of the term in this application. As a further example, as used in this application, the term "circuit" would also cover an implementation of only a processor (or multiple processors) or a portion of a processor and its accompanying software and / or firmware. The term "circuit" would also cover (for example and if applicable to the particular element) a baseband integrated circuit or application processor integrated circuit for a mobile phone, or a similar integrated circuit in a server, cellular network device, or other network device.

[0095] In an embodiment, in combination Figures 1A to 5 At least some of the processes described may be performed by an apparatus including corresponding components for performing at least some of the processes described. Some example components for performing these processes may include at least one of the following: a detector, a processor (including dual-core and multi-core processors), a digital signal processor, a controller, a receiver, a transmitter, an encoder, a decoder, a memory, RAM, ROM, software, firmware, a display, a user interface, a display circuit, a user interface circuit, user interface software, display software, a circuit, an antenna, an antenna circuit, and a circuit system. In an embodiment, at least one processor, a memory, and a computer program code constitute a processing component or include one or more computer program code portions, which are used to perform the processing according to Figures 1A to 5 Any embodiment or operation thereof to perform one or more operations.

[0096] According to yet another embodiment, an apparatus for performing an embodiment comprises a circuit comprising at least one processor and at least one memory comprising computer program code. When activated, the circuit causes the apparatus to perform the Figures 1A to 5 At least some of the functions or operations of any embodiment of the present invention.

[0097] The techniques and methods described herein can be implemented by various means. For example, these techniques can be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. For hardware implementation, the device of the embodiment can be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be performed by a module (e.g., a process, a function, etc.) of at least one chipset. The software code can be stored in a memory unit and executed by a processor. The memory unit can be implemented in a processor or outside a processor. In the latter case, it can be communicatively coupled to the processor via various means known in the art. In addition, as will be appreciated by those skilled in the art, the components of the system described herein can be rearranged and / or supplemented by additional components to facilitate the implementation of the various aspects described therein, etc., and they are not limited to the precise configurations set forth in the accompanying drawings given.

[0098] The embodiments as described may also be implemented in the form of a computer process defined by a computer program or part thereof. Figures 1A to 5 Embodiments of the described methods can be performed by executing at least a portion of a computer program including corresponding instructions. The computer program can be in source code form, object code form, or some intermediate form, and it can be stored in some carrier, which can be any entity or device capable of carrying the program. For example, the computer program can be stored on a computer program distribution medium readable by a computer or processor. The computer program medium can be, for example, but not limited to, a recording medium, a computer memory, a read-only memory, an electric carrier signal, a telecommunication signal, and a software distribution package. The computer program medium can be, for example, a non-transitory medium. The software coding for executing the illustrated and described embodiments is completely within the scope of those of ordinary skill in the art. In an embodiment, a computer-readable medium includes the computer program.

[0099] Although the present invention has been described above with reference to the examples according to the accompanying drawings, it is clear that the present invention is not limited thereto, but can be modified in various ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate rather than limit the embodiments. With the advancement of technology, it will be apparent to those skilled in the art that the inventive concept can be implemented in various ways. In addition, it will be clear to those skilled in the art that the described embodiments can, but not necessarily, be combined with other embodiments in various ways.

[0100] Abbreviations

[0101] 5MBS 5G Multicast Broadcast Service

[0102] DC Dual Connection

[0103] MBS Multicast Broadcast Service

[0104] MN Master Node

[0105] QoS Quality of Service

[0106] QFI QoS Flow Identifier

[0107] TNLI Transport Network Layer Information

[0108] SC-MRB Single Cell Multicast Radio Bearer

[0109] SN Secondary Node

[0110] PSCell primary and secondary cells

[0111] UE User Equipment.

Claims

1. A method for a second network node of a wireless communication network, the method comprising: receiving a message from a first network node configured to provide a multicast broadcast service MBS to a user equipment UE, the message comprising an MBS identifier identifying the MBS and comprising at least one data flow identifier corresponding to at least one data flow for providing the MBS to be offloaded from the first network node to the second network node; determining whether a tunnel associated with the MBS identifier exists between the second network node and a user plane entity; Based on the determination, sending a response message to the first network node indicating whether to request to establish a new tunnel for the MBS; as well as Using an existing tunnel or the new tunnel requested to be established to provide the MBS; Wherein, if the tunnel associated with the MBS identifier between the second network node and the user plane entity exists, the response message includes transport network layer information corresponding to the existing tunnel and / or an indicator for indicating that establishment of a new tunnel for the MBS identifier is not requested; The method further comprises: detecting a need to continue using the tunnel between the second network node and the user plane entity for providing the MBS to at least one other UE; and The need to continue using the tunnel is indicated to the first network node.

2. The method according to claim 1, wherein: If the tunnel associated with the MBS identifier between the second network node and the user plane entity does not exist, the response message includes transport network layer information for establishing a tunnel between the second network node and the user plane entity.

3. The method according to claim 1 or 2, wherein: If the tunnel associated with the MBS identifier between the second network node and the user plane entity exists, the response message is generated such that it does not include transport network layer information about the existing tunnel.

4. A method for a first network node of a wireless communication system, the method comprising: Determine to offload at least one data flow for providing a multicast broadcast service MBS to a second network node, wherein the MBS is provided to a user equipment UE; sending a message to the second network node, the message comprising an MBS identifier identifying the MBS and at least one data flow identifier corresponding to the at least one data flow to be offloaded from the first network node to the second network node; receiving, from the second network node, a response message indicating whether to request establishment of a new tunnel between the second network node and a user plane entity for providing the MBS to the UE; Determining, based on the response message, that a tunnel for the MBS already exists between the second network node and the user plane entity; Based on the determination, indicating to a session management entity that the tunnel for the MBS already exists between the second network node and the user plane entity; The determining that the tunnel exists is based on the response message including the transport network layer information corresponding to the tunnel and / or an indicator for indicating that a new tunnel for the MBS is not requested to be established; and If the establishment of the new tunnel is requested, initiating the establishment of the new tunnel; If the request is to establish the new tunnel, the response message includes transport network layer information used to establish the new tunnel between the second network node and the user plane entity.

5. The method according to claim 4, wherein: Initiating establishment of the new tunnel includes: sending a tunnel creation request to the session management entity.

6. The method according to claim 5, wherein: The tunnel creation request includes the transport network layer information received from the second network node.

7. An apparatus for a second network node of a wireless communication network, the apparatus comprising: means for receiving a message from a first network node configured to provide a multicast broadcast service MBS to a user equipment UE, wherein the message comprises an MBS identifier identifying the MBS and at least one data flow identifier corresponding to at least one data flow to be offloaded from the first network node to the second network node for providing the MBS; means for determining whether a tunnel associated with the MBS identifier exists between the second network node and a user plane entity; means for sending, based on the determination, to the first network node a response message indicating whether to request establishment of a new tunnel for the MBS; and means for using an existing tunnel or the new tunnel requested to be established for providing the MBS; Wherein, if the tunnel associated with the MBS identifier between the second network node and the user plane entity exists, the response message includes transport network layer information corresponding to the existing tunnel and / or an indicator for indicating that establishment of a new tunnel for the MBS identifier is not requested; The device further comprises: means for detecting a need to continue using the tunnel between the second network node and the user plane entity for providing the MBS to at least one other UE; and Means for indicating to the first network node the need to continue using the tunnel.

8. The device according to claim 7, wherein: If the tunnel associated with the MBS identifier between the second network node and the user plane entity does not exist, the response message includes transport network layer information for establishing a tunnel between the second network node and the user plane entity.

9. The device according to claim 7 or 8, wherein: If the tunnel associated with the identifier between the second network node and the user plane entity exists, the response message is generated such that it does not include transport network layer information about the existing tunnel.

10. An apparatus for a first network node of a wireless communication system, the apparatus comprising: means for determining to offload at least one data flow for providing a multicast broadcast service MBS to a second network node, wherein the MBS is provided to a user equipment UE; means for sending a message to the second network node, wherein the message comprises an MBS identifier identifying the MBS and at least one data flow identifier corresponding to the at least one data flow to be offloaded from the first network node to the second network node; means for receiving, from the second network node, a response message indicating whether to request establishment of a new tunnel between the second network node and a user plane entity for providing the MBS; and means for initiating establishment of the new tunnel if establishment of the new tunnel is requested; wherein, based on the response message, it is determined that a tunnel for the MBS already exists between the second network node and the user plane entity; Based on the determination, indicating to a session management entity that the tunnel for the MBS already exists between the second network node and the user plane entity; The determining that the tunnel exists is based on that the response message includes the transport network layer information corresponding to the tunnel and / or an indicator for indicating that a new tunnel for the MBS is not requested to be established; If the request is to establish the new tunnel, the response message includes transport network layer information used to establish the new tunnel between the second network node and the user plane entity.

11. The device according to claim 10, wherein: Initiating establishment of the new tunnel includes: sending a tunnel creation request to the session management entity.

12. The device according to claim 11, wherein The tunnel creation request includes the transport network layer information received from the second network node.

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