CN111526553B

CN111526553B - Method for executing UE, method for executing SMF entity and SMF entity

Info

Publication number: CN111526553B
Application number: CN202010409871.4A
Authority: CN
Inventors: 熊春山
Original assignee: Tencent Technology Shenzhen Co Ltd
Current assignee: Tencent Technology Shenzhen Co Ltd
Priority date: 2020-05-13
Filing date: 2020-05-13
Publication date: 2024-06-18
Anticipated expiration: 2040-05-13
Also published as: CN111526553A

Abstract

The present disclosure provides a method performed by a user device and a corresponding user device, and a method performed by a session management function entity and a corresponding session management function entity. The method performed by the user device comprises: determining an activation mode for activating the multicast service; activating the multicast service according to the determined activation mode and at least through a session management function entity, wherein a multicast service session corresponding to the multicast service is performed in the activation process of the multicast service; and receiving service data corresponding to the multicast service.

Description

Method for executing UE, method for executing SMF entity and SMF entity

Technical Field

The present disclosure relates to the field of wireless communications, and more particularly to a method performed by a User Equipment (UE) and a corresponding UE, and a method performed by a session management function (Session Management Function, SMF) entity and a corresponding SMF entity.

Background

Existing wireless communication systems may support multimedia broadcast and multicast services (Multimedia Broadcast and Multicast Service, MBMS). In particular, MBMS can be classified into a multicast service and a broadcast service. Multicasting, which may also be referred to as multicasting, is the transmission of the same content to multiple users. In a multicast manner, data for all target entities may be transmitted at once, and data may be transmitted only for specific users. Broadcast is also the transmission of the same content to multiple users, but it does not make a user's selection, so there may be situations where no user is available in the network but still data transmission is made.

In a conventional wireless communication system, a technical solution of how a User Equipment (UE) performs a multicast service has been proposed. For example, when a plurality of UEs all want to perform the same multicast service, first, each UE of the plurality of UEs needs to activate the multicast service. A plurality of UEs that have activated the multicast service may be regarded as one multicast group. Then, a user plane corresponding to the multicast group needs to be established, so that the network transmits service data corresponding to the multicast service to the multicast group through the established user plane, thereby enabling the corresponding UE to acquire the service data corresponding to the multicast service.

The user plane establishment described above is for one multicast Group (i.e., per Group) rather than for a single UE. The technical scheme is suitable for the situation that the multicast service is activated by a plurality of UE before the network transmits service data corresponding to the multicast service to the plurality of UE. However, in case the network has already started transmitting traffic data corresponding to the multicast traffic to a plurality of UEs, there may be some other UEs that want to do the multicast traffic (e.g. the UE just turned on). The solution described above is then no longer applicable.

Disclosure of Invention

To overcome the drawbacks of the prior art, the present disclosure proposes a method performed by a user device and a corresponding user device, and a method performed by a session management function entity and a corresponding session management function entity.

According to one aspect of the present disclosure, there is provided a method performed by a user device, comprising: determining an activation mode for activating the multicast service; activating the multicast service according to the determined activation mode and at least through a session management function entity, wherein a multicast service session corresponding to the multicast service is performed during the activation of the multicast service; and receiving service data corresponding to the multicast service.

According to one example of the present disclosure, before the determining the activation manner for activating the multicast service, the method further includes: and determining a first identifier and a second identifier corresponding to the multicast service, wherein the first identifier and the second identifier are used for an access and mobility management function entity to select the session management function entity.

According to one example of the present disclosure, the first identification is used to identify a network fragment corresponding to the multicast service, and the second identification is used to identify a data network corresponding to the multicast service.

According to one example of the present disclosure, the determining the first and second identities corresponding to the multicast service includes: obtaining, from a policy control function entity, a user device routing policy rule corresponding to each of the at least one multicast service, wherein each user device routing policy rule includes at least a multicast address of the corresponding multicast service; determining a user device routing policy rule corresponding to the multicast service according to the multicast address of the multicast service; and determining a first identifier and a second identifier corresponding to the multicast service according to the determined routing policy rule of the user device.

According to one example of the present disclosure, the activating the multicast service according to the determined activation manner and at least by the session management function entity comprises: determining a third identification, wherein the third identification is used for identifying a user device multicast service context established for activating the multicast service; transmitting a request for activating the user device multicast service context to the session management function entity, wherein the request for activating the user device multicast service context comprises the third identifier and a multicast address of the multicast service; a response to the request for activating the user device multicast service context is received from the session management function entity, the response including a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated.

According to one example of the present disclosure, wherein sending a request to the session management function entity to activate the user device multicast service context comprises: a request for activating the user device multicast service context is sent via the access and mobility management function entity to the session management function entity.

According to one example of the present disclosure, wherein receiving a response from the session management function entity to the request for activating the user device multicast service context comprises: a response to the request for activating the user device multicast service context is received from the session management function entity via a serving base station of the user device and the access and mobility management function entity.

According to one example of the present disclosure, wherein prior to determining the third identity, the method further comprises: acquiring a first identifier, a second identifier and a multicast address from the session management functional entity; it is determined whether the acquired first identity is identical to the determined first identity, whether the acquired second identity is identical to the determined second identity, and whether the acquired multicast address is identical to the multicast address of the multicast service.

According to one example of the present disclosure, before obtaining a first identity, a second identity and a multicast address from the session management function entity, the method further comprises: acquiring an internet protocol address from the session management function entity according to the first identifier and the second identifier; and sending a data packet to a network according to the acquired internet protocol address so as to acquire the data packet by a user plane functional entity in the network, wherein the data packet is used for indicating the multicast service which the user device wants to activate.

According to one example of the present disclosure, wherein obtaining an internet protocol address from the session management function based on the first identification and the second identification comprises: selecting the session management function entity and establishing a protocol data unit session according to the first identifier and the second identifier, and acquiring an internet protocol address from the session management function entity; and wherein said sending the data packet to the network according to the acquired internet protocol address so that the user plane function entity in the network acquires the data packet comprises: transmitting a data packet to a network according to the acquired internet protocol address so that a user plane functional entity participating in the establishment of the protocol data unit session in the network acquires the data packet; wherein the destination address of the data packet is or the protocol part of the data packet comprises the multicast address of the multicast service.

According to one aspect of the disclosure, a method performed by a session management function entity comprises: receiving a request from a user device for activating a user device multicast service context established by the user device for activating a multicast service, the request for activating the user device multicast service context including the third identification and a multicast address of the multicast service, the third identification identifying the user device multicast service context; determining a response to the request for activating a user device multicast service context, wherein the response includes a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated; obtaining a fifth identifier corresponding to the multicast service, wherein the fifth identifier is used for identifying the start of a multicast service session corresponding to the multicast service; and conducting the multicast service session and transmitting the response to the user device.

According to one example of the present disclosure, the receiving a request from a user device to activate a user device multicast service context comprises: a request for activating a user device multicast service context is received from the user device via an access and mobility management function entity.

According to one example of the present disclosure, wherein transmitting the response to the user device comprises: the response is sent to the user device via the serving base station of the user device and an access and mobility management function entity.

According to one example of the present disclosure, before the receiving a request from a user device to activate the user device multicast service context, the method further comprises: establishing a protocol data unit session; assigning an internet protocol address to said user device; acquiring a multicast address of a multicast service to be activated by the user equipment from a user plane function entity participating in the establishment of the protocol data unit session, wherein the multicast address is acquired after the user equipment transmits a data packet to a network including the user plane function entity according to the internet protocol address, wherein the data packet is used for indicating the multicast service to be activated by the user equipment; when the session management function entity decides to instruct the user device to activate the multicast service, a request for instructing the user device to activate the multicast service is sent to the user device, wherein the request for instructing the user device to activate the multicast service includes a first identifier, a second identifier, and a multicast address of the multicast service corresponding to the multicast service to be activated by the user device.

According to one example of the present disclosure, further comprising: a dedicated identity of the user equipment and an identity of a serving base station of the user equipment are received from the access and mobility management function entity.

According to one example of the present disclosure, further comprising: the identity of the serving base station of the user device is recorded in the user device multicast service context in order to obtain the identity of the serving base station of all user devices that activate the multicast service by the session management function entity.

According to one example of the present disclosure, wherein determining a response to the request to activate the user device multicast service context comprises: determining whether the user device is capable of using the multicast service; transmitting a notification to the application function entity when the user device is capable of using the multicast service, wherein the notification is a notification of the multicast service authorization request; and receiving a response to the notification from the application function entity, wherein the response to the notification includes a fourth identification corresponding to the multicast service.

According to one example of the present disclosure, the notification includes at least the first identification, the second identification, a multicast address of the multicast service, and an identification of the session management function entity, wherein the identification of the session management function entity facilitates the application function entity to obtain session management function entities involved in activating the multicast service by all user devices that are to activate the multicast service.

According to one example of the present disclosure, wherein sending a notification to the application function entity comprises: a notification is sent to the application function entity via the network opening function entity.

According to one example of the present disclosure, the notification may further include an identification of the application function entity, such that the network open function entity determines the application function entity according to the identification of the application function entity and sends the notification to the application function entity.

According to one example of the present disclosure, wherein receiving a response to the notification from the application function entity comprises: a response to the notification is received from the application function entity via a network open function entity.

According to one example of the present disclosure, wherein conducting the multicast service session comprises: a first request is received from a policy control function entity corresponding to the session management function entity, wherein the first request is used for requesting the start of the multicast service session, and the first request at least comprises a first identifier of the user device, a fourth identifier corresponding to the multicast service, a quality of service rule of at least one data stream corresponding to the multicast service, and an identifier of the multicast service session.

According to one example of the present disclosure, the first request is determined by the policy control function entity based on a second request received from a network opening function entity or an application function entity, the second request requesting the start of a multicast traffic session from the policy control function entity by the network opening function entity or the application function entity.

According to one example of the present disclosure, the second request includes at least a first identification of the user device, the fourth identification, an identification of the session management function entity, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, and an identification of the multicast service session.

According to one example of the present disclosure, the policy control function is determined by the network opening function or the application function according to an identification of the session management function.

According to one example of the present disclosure, the second request is determined by the network opening function entity according to a third request received from an application function entity, the third request being for the application function entity to request a start of a multicast traffic session from the network opening function entity.

According to one example of the present disclosure, the third request includes at least a second identification of the user device, the fourth identification, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, and an identification of the multicast service session.

According to one example of the present disclosure, any one of the first request, the second request, and the third request may further include an aggregate maximum rate corresponding to the multicast traffic.

According to one example of the present disclosure, wherein conducting the multicast service session further comprises: and generating a service quality flow identifier, a service quality configuration file and a service quality execution rule corresponding to each data flow according to the service quality rule of each data flow.

According to one example of the present disclosure, wherein conducting the multicast service session further comprises: selecting a user plane function entity according to the fourth identifier; transmitting a fourth request to the selected user plane function entity, wherein the fourth request is used for establishing transmission resources of the multicast service session; and obtaining a response to the fourth request from the selected user plane functional entity, the response to the fourth request including a tunnel multicast address allocated by the selected user plane functional entity for transmitting traffic data corresponding to the multicast traffic, and a sixth identification corresponding to the tunnel multicast address, wherein the tunnel multicast address is used for multicast tunneling between network entities, and the sixth identification is used for identifying a transmission tunnel of the multicast traffic.

According to one example of the present disclosure, wherein conducting the multicast service session further comprises: selecting a user plane function entity according to the fourth identifier; transmitting a fourth request to the selected user plane functional entity, wherein the fourth request is used for establishing transmission resources of the multicast service session, the fourth request comprises a tunnel multicast address allocated by the session management functional entity for transmitting service data corresponding to the multicast service, and a sixth identifier corresponding to the tunnel multicast address, wherein the tunnel multicast address is used for multicast tunneling between network entities, and the sixth identifier is used for identifying a transmission tunnel of the multicast service; a response to the fourth request is obtained from the selected user plane function entity, wherein the response to the fourth request is an acknowledgment to the fourth request.

According to one example of the present disclosure, the fourth request includes at least a multicast address of the multicast service, a quality of service enforcement rule of the at least one data flow, and an aggregate maximum rate corresponding to the multicast service.

According to one example of the present disclosure, the conducting the multicast service session and transmitting the response to the user device comprises: and sending first information to the access and mobility management function entity, wherein the first information comprises the response and information related to the multicast service session, so that the access and mobility management function entity sends a fifth request to a corresponding serving base station according to the information related to the multicast service session, and sends the response to the user equipment via the corresponding serving base station, wherein the fifth request is used for requesting the start of the multicast service session.

According to one example of the present disclosure, the information related to the multicast service session includes at least the fourth identification, an aggregate maximum rate corresponding to the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow, the tunnel multicast address, and the sixth identification.

According to one aspect of the present disclosure, there is provided a user apparatus comprising: a determining unit configured to determine an activation manner for activating the multicast service; an activation unit configured to activate the multicast service according to the determined activation manner and at least through a session management function entity, wherein a multicast service session corresponding to the multicast service is performed during activation of the multicast service; and a receiving unit configured to receive service data corresponding to the multicast service.

According to one aspect of the present disclosure, there is provided a session management functional entity comprising: a receiving unit configured to receive a request from a user device for activating a user device multicast service context, the user device multicast service context being established for activating a multicast service, the request for activating the user device multicast service context including the third identification and a multicast address of the multicast service, the third identification being used for identifying the user device multicast service context; a determining unit configured to determine a response to the request for activating a user device multicast service context, wherein the response comprises a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated; an obtaining unit configured to obtain a fifth identifier corresponding to the multicast service, where the fifth identifier is used to identify a start of a multicast service session corresponding to the multicast service; a control unit configured to conduct the multicast service session; and a transmitting unit configured to transmit the response to the user device.

According to one aspect of the present disclosure, there is provided a user apparatus comprising: a processor; and a memory, wherein the memory stores a computer executable program that, when executed by the processor, performs the method performed by the user device.

According to one aspect of the present disclosure, there is provided a session management functional entity comprising: a processor; and a memory, wherein the memory stores a computer executable program that, when executed by the processor, performs the method performed by the session management function entity.

According to another aspect of the present disclosure, there is provided a computer readable storage medium having stored thereon instructions which, when executed by a processor, cause the processor to perform the above-described method.

According to the method performed by the user device and the corresponding user device according to the above aspects of the present disclosure, the user device may determine an activation manner for activating the multicast service and activate the multicast service according to the determined activation manner and at least through a session management function entity in the network, thereby optimizing or being compatible with a conventional procedure for activating the multicast service. In addition, in the process of activating the multicast service, a multicast service session corresponding to the multicast service is performed, so that a user plane corresponding to the multicast service is established in the process of activating the multicast service.

In addition, according to the method executed by the session management function entity and the corresponding session management function entity in the above aspects of the disclosure, in the process of activating the multicast service, the session management function entity may receive the third identifier corresponding to the multicast service to be activated by the user device and the multicast address of the multicast service from the user device, and determine the fourth identifier corresponding to the multicast service and the fifth identifier according to at least these information, so as to enable the multicast service session corresponding to the multicast service to be performed according to the fifth identifier to establish the user plane corresponding to the multicast service, and feed back the fourth identifier to the user device so that the user device activates the multicast service, thereby implementing the establishment of the user plane corresponding to the multicast service in the process of activating the multicast service.

Drawings

The above and other objects, features and advantages of the present disclosure will become more apparent by describing in more detail embodiments thereof with reference to the attached drawings. The accompanying drawings are included to provide a further understanding of embodiments of the disclosure, and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure, without limitation to the disclosure. In the drawings, like reference numerals generally refer to like parts or steps.

Fig. 1 is a schematic diagram of an architecture of a wireless communication system in which embodiments of the present disclosure may be applied.

Fig. 2 is a flowchart of a method performed by a user device according to an embodiment of the present disclosure.

Fig. 3 is a flowchart of a method performed by a user device for determining a first identity and a second identity corresponding to a multicast service according to an embodiment of the present disclosure.

Fig. 4 is a flowchart of a method performed by a session management function entity when a user device activates multicast traffic according to a first activation manner according to an embodiment of the present disclosure.

Fig. 5 is a flowchart of a method performed by a session management function entity when a user device activates multicast traffic according to a second activation manner according to an embodiment of the present disclosure.

Fig. 6 is a schematic flow of activating a multicast service and establishing a user plane corresponding to the multicast service based on a first activation manner in a wireless communication system according to an embodiment of the present disclosure.

Fig. 7 is a schematic flow of activating a multicast service and establishing a user plane corresponding to the multicast service based on a second activation manner in a wireless communication system according to an embodiment of the present disclosure.

Fig. 8 is a schematic structural view of a user device according to an embodiment of the present disclosure.

Fig. 9 is a schematic structural diagram of a session management functional entity according to an embodiment of the present disclosure.

Fig. 10 is another structural schematic diagram of a session management functional entity according to an embodiment of the present disclosure.

Fig. 11 illustrates a schematic diagram of an architecture of another wireless communication system in which the principles of embodiments of the present disclosure may be applied.

Fig. 12 is a schematic flow of activating a multicast service and establishing a user plane corresponding to the multicast service based on the wireless communication system shown in fig. 11.

Fig. 13 illustrates an architecture of a device according to an embodiment of the present disclosure.

Detailed Description

In order to make the objects, technical solutions and advantages of the present disclosure more apparent, exemplary embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements throughout. It should be understood that: the embodiments described herein are merely illustrative and should not be construed as limiting the scope of the present disclosure. In addition, the User Equipment (UE) described herein may include various types of terminals, such as mobile terminals or IP terminals. For convenience, these terms may sometimes be used interchangeably.

First, a wireless communication system in which the embodiments of the present disclosure can be applied will be described with reference to fig. 1. Fig. 1 is a schematic diagram of an architecture of a wireless communication system in which embodiments of the present disclosure may be applied. The wireless communication system may be a fifth generation (5G) wireless communication system, or may be any other type of wireless communication system, such as a 6G wireless communication system, etc. Hereinafter, embodiments of the present disclosure are described by taking a 5G wireless communication system as an example, but it should be recognized that the following description may also be applicable to other types of wireless communication systems.

Specifically, the wireless communication system 100 includes an application function (Application Function, AF) entity 110, a network opening function (Network Exposure Function, NEF)/policy control function (Policy Control Function, PCF) entity 120, a session management function (Session Management Function, SMF) entity 130, an access and mobility management function (ACCESS AND Mobility management Function, AMF) entity 140, a user plane function (User Plane Function, UPF) entity 150, and radio access networks (Radio Access Network, RAN) 161-162, and UEs 171-172 served thereby, wherein the NEF/PCF entity 120, the SMF entity 130, and the AMF entity 140 belong to entities of a control plane, and the UPF entity 150 belongs to entities of a user plane. In addition, the AF described herein may also be referred to as a service layer (SERVICE LAYER). Each entity described herein may be one or more servers. In this disclosure, an "entity" may also be referred to as a node. For convenience, entities and nodes are sometimes used interchangeably.

In addition, the AF entity 110 may provide service data, support application impact on a service path, interact with a measurement framework for policy control, and the like. The NEF entity in the NEF/PCF entity 120 may support QoS capability opening, event subscription capability opening, traffic steering of AF requests, and parameter issuance of AF requests, etc. PCF entities in NEF/PCF entity 120 may support a unified policy framework to manage network behavior, provide policy rules to control the control plane, etc. The SMF entity 130 may support session management, etc., where the session management may include session establishment, modification, release, etc. The AMF entity 140 may support access authentication, mobility management, registration management, connection management, lawful interception of the UE, support transmission of session management information between the UE and the SMF entity, and so on. The UPF entity 150 may have routing functions for data packets, e.g., may obtain data packets from the AF entity 110 and send data packets to RANs 161-162, etc. RAN 161 and/or 162 may be an access network comprised of base stations. The base station here may be any type of base station, such as a 5G base station, or a base station in a conventional communication system, or a WiFi AP, etc.

In addition, UEs 171 and/or 172 may be connected to RANs 161 and/or 162 via Uu interfaces. RAN 161 and/or 162 may be coupled to AMF entity 140 via an N2 interface and UPF entity 150 via an N3 interface. The UPF entity 150 may be connected to the SMF entity 130 through an N4 interface and to the AF entity 110 through an N6 interface. The AMF entity 140 is connected to the SMF entity 130 through an N11 interface. The SMF entity 130 is connected to the NEF/PCF entity 120 via an N7 interface. The NEF/PCF entity 120 is connected to the AF entity 110 via an N5 or Nnef interface.

In addition, fig. 1 also shows the service area between the UPF entity 150 and RANs 161-162, as indicated by the ellipses in fig. 1. In the present disclosure, a plurality of routing switch devices (e.g., routers) may be deployed within the service area, wherein each routing switch device may be coupled to the UPF entity 150 and to one or more RANs such that the UPF entity 150 transmits traffic data to each routing device and each routing device in turn transmits the traffic data to the corresponding RAN.

In addition, in the present disclosure, the AF entity may support multicast/broadcast services (Multicast Broadcast Service, MBS). Therefore, the AF entity may also be referred to as MBS AF entity. For convenience, these terms may sometimes be used interchangeably.

It should be appreciated that while the number of various types of entities is shown as one in fig. 1, this is merely illustrative and the wireless communication system may include a greater number of entities. Furthermore, while two RANs and two UEs are shown in fig. 1, this is merely illustrative, and the wireless communication system may include fewer or more RANs and/or fewer or more UEs, and accordingly, the wireless communication system may include fewer or more cells.

In the present disclosure, when a UE wants to perform a multicast service, the UE needs to activate the multicast service first. During activation of the multicast service, the network may establish a user plane for the UE and corresponding to the multicast service so that the network transmits service data corresponding to the multicast service to the UE. Specifically, during activation of the multicast service, the network may begin conducting a multicast service session for the UE and corresponding to the multicast service. In the above procedure, communication between a plurality of entities (e.g., AF entity 110, NEF/PCF entity 120, SMF entity 130, AMF entity 140, UPF entity 150, etc. in fig. 1) in a wireless communication system will be involved.

The method performed by the UE in the above procedure will be described below with reference to fig. 2. Fig. 2 is a flow chart of a method 200 performed by a user device according to an embodiment of the present disclosure. As shown in fig. 2, in step S201, the UE determines an activation manner for activating a multicast service. In step S201, the determined activation manner may be the first activation manner or the second activation manner.

According to one example of the present disclosure, in a first activation mode, the UE does not need to establish a protocol data unit (Protocol Data Unit, PDU) session and obtain an IP address (e.g., an IP address is assigned by the SMF entity) before activating the multicast service. That is, in the first activation mode, the UE does not need to perform steps similar to step 1 shown in fig. 1. Thus, the first activation approach optimizes the traditional flow of activating multicast traffic.

Further, in accordance with one example of the present disclosure, in a second activation mode, the UE needs to establish a PDU session and obtain an IP address (e.g., an IP address is assigned by the SMF entity) before activating the multicast service. That is, in the second activation mode, the UE needs to perform steps similar to step 1 shown in fig. 1. Thus, the second activation scheme is compatible with the conventional procedure of activating multicast traffic.

In the present disclosure, in step S201, the UE may determine an activation manner for activating the multicast service according to its own attribute. The attributes described herein may refer to the support capabilities of the UE for various applications. For example, when the UE supports only a mobile application or the UE does not need an IP data transmission function, the UE may determine that an activation manner for activating a multicast service is a first activation manner. For example, when the UE needs to support an IP-based application, the UE may determine that the activation manner for activating the multicast service is a second activation manner.

It is to be appreciated that in step S201, the UE may also determine the activation manner for activating the multicast service according to other manners, which is not limited in this disclosure.

Furthermore, according to one example of the present disclosure, prior to step S201, the method 200 may further include: the UE may determine a first identity and a second identity corresponding to the multicast service, wherein the first identity and the second identity are used for an access and mobility management function entity to select the session management function entity. In particular, the first identification may be used to identify a network fragment corresponding to the multicast service. For example, the first identification may be single network segment selection assistance information (Single Network Slice Selection Assistance Information, S-NSSAI). Further, the second identification may be used to identify a data network corresponding to the multicast service. For example, the second identification may be a data network name (Data Network Name, DNN).

In this example, the UE may determine the first and second identities corresponding to the multicast traffic by the method 300 shown in fig. 3. Fig. 3 is a flowchart of a method 300 performed by a user device for determining a first identity and a second identity corresponding to a multicast service according to an embodiment of the present disclosure.

As shown in fig. 3, in step S301, the UE may obtain, from a Policy Control Function (PCF) entity, user device routing policy (UE Route Selection Policy Rule, URSP) rules corresponding to each of at least one multicast service, wherein each user device routing policy rule includes at least a multicast address of the corresponding multicast service. For example, first, the UE may initiate a registration procedure with the network; then, in the process that the AMF entity and the PCF entity establish the UE policy association (UE Policy Association), the PCF entity may provide URSP rules corresponding to each of the at least one multicast service to the UE through the AMF entity, and accordingly, the UE may obtain URSP rules corresponding to each of the at least one multicast service from the PCF entity through the AMF entity.

Then, in step S302, the UE may determine a user equipment routing policy rule corresponding to the multicast service according to the multicast address of the multicast service. For example, when the UE wants to activate a multicast service, the UE may determine URSP rules corresponding to the multicast service according to the multicast address of the multicast service.

Then, in step S303, the UE may determine a first identifier and a second identifier corresponding to the multicast service according to the determined user device routing policy rule. For example, the UE may obtain a routing descriptor (Route Selection Descriptor) according to URSP rules corresponding to the multicast service, wherein the routing descriptor includes a first identity and a second identity; then, the UE uses the first identifier and the second identifier included in the routing descriptor as the first identifier and the second identifier corresponding to the multicast service.

It should be appreciated that in the present disclosure, the multicast address of the multicast service may be an IPv4 multicast address or an IPv6 multicast address, which is not limited in this disclosure.

Returning to fig. 2, after step S201, in step S202, the UE activates the multicast service according to the determined activation manner and at least through a session management function entity, wherein a multicast service session corresponding to the multicast service is performed during activation of the multicast service. That is, a user plane corresponding to the multicast service is established during the activation of the multicast service.

According to one example of the present disclosure, when the activation manner determined by the UE in step S201 is the first activation manner, the UE performs step S202'. In step S202', the UE activates the multicast service according to the first activation manner and at least through a session management function entity. In this example, step S202 'may include 3 sub-steps, step S2021', step S2022', and step S2023', respectively.

Specifically, in step S2021', the UE may determine a third identification, where the third identification is used to identify a user equipment multicast service context established for activating the multicast service. For example, the UE may assign an Identification (ID) to the user equipment multicast service context. The "user equipment multicast service Context established for activating the multicast service" described herein may also be referred to as a user equipment multicast service Context (MBS UE Context) for the multicast service. Accordingly, the third identification may also be referred to as an identification (MBS UE Context ID) of the user device multicast service context for the multicast service.

It is to be appreciated that the UE can employ multicast addresses of different multicast services to activate a plurality of different multicast services. Accordingly, the UE may assign different third identities for different multicast services, thereby identifying the user equipment multicast service contexts established for activating these different multicast services, respectively.

Then, in step S2022', the UE sends a request for activating the user equipment multicast service context to the session management function entity, the request for activating the user equipment multicast service context including the third identification and the multicast address of the multicast service. For example, the UE may send a request for activating the user equipment multicast service context to the session management function entity via the access and mobility management function entity.

Specifically, first, the UE may send an uplink Non-Access Stratum (NAS) Transport (ULNAS Transport) message to the AMF entity, where the UL NAS Transport message includes at least three cells, a first cell is a first identifier corresponding to the multicast service, a second cell is a second identifier corresponding to the multicast service, and a third cell is a request for activating MBS UE Context. The request for activating the MBS UE Context may be denoted Active MBS UE Context Request and may include a third identification corresponding to the multicast service and a multicast address of the multicast service. In an example where the first identity is S-NSSAI, the second identity is DNN, and the third identity is MBS UE Context ID, the UL NAS Transport message sent by the UE to the AMF entity may include three cells, where the first cell is S-NSSAI corresponding to the multicast service, the second cell is DNN corresponding to the multicast service, and the third cell is a request for activating MBS UE Context, where the request for activating MBS UE Context includes MBS UE Context ID corresponding to the multicast service and a multicast address of the multicast service.

In the present disclosure, the UE may encapsulate the "request for activating MBS UE Context" described herein using a specific format. For example, the specific format may be a session management Container (N1 MBS SM Container) of the multicast service related to the N1 interface.

Then, the AMF entity may select a corresponding SMF entity according to the first identifier and the second identifier corresponding to the multicast service. In an example where the first identification is S-NSSAI and the second identification is DNN, the AMF entity may select a corresponding SMF entity according to S-NSSAI and DNN corresponding to the multicast service.

The AMF entity may then send a request to the corresponding SMF entity via the Nsmf interface, which may be used to request creation of MBS UE Context related to the MBS session. The request may be denoted Nsmf _ MBSSession _ CreateMBSUEContext Request. The request may include a first identifier, a second identifier, which correspond to the multicast service, and the above-described "request for activating MBS UE Context". In the example where the first identification is S-NSSAI, the second identification is DNN, and the third identification is MBS UE Context ID, the AMF entity may send a request to the SMF entity over the Nsmf interface, which may include S-NSSAI corresponding to the multicast service, DNN corresponding to the multicast service, and "request for activating MBS UE Context" described above.

Furthermore, according to one example of the present disclosure, the request sent by the AMF entity to the SMF entity may also include a dedicated identity of the UE. For example, the UE's private identity may be a Subscription permanent identifier (Subscription PERMANENT IDENTIFIER, SUPI). Further, according to another example of the present disclosure, the request sent by the AMF entity to the SMF entity may also include an identification of the serving base station of the UE. For example, the identity of the serving base station of the UE may be a corresponding RAN ID, which may be reported to the AMF entity by the RAN accessed by the UE. Furthermore, according to another example of the present disclosure, the request sent by the AMF entity to the SMF entity may also include both the UE's dedicated identity and the identity of the UE's serving base station, e.g., the SUPI and corresponding RAN ID of the UE.

After step S2022', the SMF entity may record the received RAN ID in the MBS UE Context of the UE, so that the SMF entity obtains the identities of the serving base stations of all user equipments activating the multicast service through the SMF entity. Furthermore, the SMF entity will determine a fourth identity corresponding to the multicast service from the received information, wherein the fourth identity is used by the user equipment to determine whether the multicast service is activated and the fourth identity is an identity assigned to the multicast service by an Application Function (AF) entity, and the SMF entity will feed back the fourth identity to the UE. These operations are described in detail below in connection with the methods performed by the SMF entity described in connection with fig. 4-5.

The fourth identification described herein may be a temporary mobile group identification (Tempory Mobile Group Identify, TMGI) assigned by the AF entity to the multicast service activated based on the multicast address.

Then, in step S2023', the UE receives a response from the session management function entity to the request for activating the user device multicast service context, the response including a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated. In particular, the UE may receive a response to the request for activating the user equipment multicast service context from the session management function entity via a serving base station of the user equipment and the access and mobility management function entity.

In particular, first, a session management function may send first information to the access and mobility management function, wherein the first information comprises a response to the request for activating the user device multicast service context and information related to the multicast service session. Further, the "information related to the multicast service session" described herein may include at least the fourth identification, an aggregate maximum rate (e.g., aggregate maximum bit rate (AGGREGATE MAXIMUM BIT RATE, AMBR)) corresponding to the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a tunnel multicast address corresponding to the multicast service, and a sixth identification. The "tunnel multicast address" described herein may be a transport layer IP multicast address (Transport IP Multicast Address) and may be referred to as a CN N3 tunnel multicast address. The "sixth identity" described herein may be a Common tunnel endpoint identity (Common-Tunnel End point ID, C-TEID) and may be referred to as CN N3C-TEID. In particular, the methods performed by the SMF entity described below in connection with fig. 4-5 will be described in detail.

When the session management function entity sends the first information to the access and mobility management function entity, the session management function entity may encapsulate "response to the request for activating the user device multicast service context" in the first information and "information related to the multicast service session" in the first information, respectively, using different specific formats. For example, the session management function entity may encapsulate the "response to the request for activating the user device multicast service context" in the first information using the first format, and encapsulate the "information related to the multicast service session" in the first information using the second format. The first format here may be a session management Container (N1 MBS SM Container) of the multicast service related to the N1 interface. The second format here may be a session management Container (N2 MBS SM Container) of the multicast service related to the N2 interface.

Then, the access and mobility management function entity sends a fifth request to the corresponding serving base station according to the information related to the multicast service session, wherein the fifth request is used for requesting the start of the multicast service session. The fifth request may include a response to the request to activate the user device multicast traffic context, the fourth identification, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast traffic, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast traffic, a tunnel multicast address corresponding to the multicast traffic, and a sixth identification.

In case that the "response to the request for activating the user equipment multicast service context" acquired by the access and mobility management function entity from the session management function entity has been encapsulated by the session management function entity (e.g., using N1 MBS SM Container encapsulation), the access and mobility management function entity does not need to encapsulate the "response to the request for activating the user equipment multicast service context" in the fifth request using a specific format (e.g., N1 MBS SM Container) when the access and mobility management function entity transmits the fifth request to the corresponding serving base station.

In addition, the "response to the request for activating the user device multicast service context" in the fifth request may be one cell of a downlink NAS Transport (DL NAS Transport) message.

The serving base station may then send a response to the user device to the request for activating the user device multicast service context. For example, the serving base station may send a response to the request for activating the user device multicast service context to the user device through radio resource control (Radio Resource Control, RRC) signaling. For example, the serving base station may send the downlink NAS transport message described above to the user equipment through RRC signaling, and one cell of the downlink NAS transport message may be "response to the request for activating the user equipment multicast service context".

Accordingly, in step S2023', the UE is able to obtain a response from the session management function entity to the request for activating the user equipment multicast service context.

A specific example of the UE obtaining a response from the session management function entity to a request for activating the user equipment multicast service context is given below.

For example, first, the SMF entity may send first information to the AMF entity through the Namf interface. The first information may be a message transmission related to the N1 interface and the N2 interface, which may be denoted as Namf _communication_n1n MESSAGETRANSFER, communicated over the Namf interface. The first information may include "the response to the request for activating the user equipment multicast service Context" described above in response to the request for activating the MBS UE Context sent by the AMF entity to the SMF entity described above in connection with step S3022'. The "response to the request for activating the user equipment multicast service Context" may include a TMGI corresponding to the multicast service and may be expressed as a response activating MBS UE Context (Activate MBS UE Context Response). The SMF entity may encapsulate the "response to activate MBS UE Context" using the N1 MBS SM Context described above. In addition, the first information may further include a TMGI corresponding to the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a CN N3 tunnel multicast address corresponding to the multicast service, and a CN N3C-TEID. The SMF entity may encapsulate the TMGI corresponding to the multicast service, the aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, the quality of service flow identification and the quality of service profile corresponding to each data flow of the multicast service, the CN N3 tunnel multicast address corresponding to the multicast service, and the CN N3C-TEID using the N2 MBS SM Container described above.

The AMF entity may then send a fifth request, which may be denoted as N2 MBS Session Start Request, to the RAN over the N2 interface for requesting the start of the multicast service session. The fifth request may include a downlink NAS Transport (DL NAS Transport) message, one cell of which is the response of activating MBS UE Context (Activate MBS UE Context Response) encapsulated using N1 MBS SM Context described above. Through the downlink NAS Transport message, the AMF entity may instruct the RAN to send the DLNAS Transport message directly to the UE. In addition, the fifth request may further include a TMGI corresponding to the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a multicast address of the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a CN N3 tunnel multicast address corresponding to the multicast service, and a CN N3C-TEID.

The RAN may then send the DL NAS Transport message described above to the UE. Accordingly, the UE may acquire the fourth identifier corresponding to the multicast service through the DL NAS Transport message. In an example where the fourth identity is a TMGI, the UE may acquire the TMGI corresponding to the multicast service through a DL NAS Transport message.

In the present disclosure, the UE successfully acquires a fourth identifier corresponding to the multicast service, which marks that the UE activates the multicast service.

Thus far, an exemplary procedure has been described in which the UE activates the multicast service according to a first activation manner and at least through a session management function entity. Next, an exemplary flow in which the UE activates the multicast service according to the second activation manner and at least through the session management function entity will be described.

According to one example of the present disclosure, when the activation manner determined by the UE in step S201 is the second activation manner, the UE performs step S202". In step S202", the UE activates the multicast service according to the second activation manner and at least through the session management function entity. In this example, step S202 "may include 7 sub-steps, step S2021", step S2022", step S2023", S2024", step S2025", step S2026", and step S2027", respectively.

Specifically, in step S2021", the UE may acquire an internet protocol address (IP address) from the session management function entity according to the first identifier and the second identifier corresponding to the multicast service. For example, the UE may select the session management function according to the first identifier and the second identifier and establish a protocol data unit session, and obtain an internet protocol address from the session management function. In an example where the first identity is S-NSSAI and the second identity is DNN, the UE may send a PDU session establishment request to the network according to S-NSSAI and DNN corresponding to the multicast service, which may include S-NSSAI and DNN corresponding to the multicast service. The AMF entity may then select one SMF entity from the plurality of SMF entities based on S-NSSAI and DNN corresponding to the multicast service. The selected SMF entity may then select a UPF entity from a plurality of UPF entities and assign an IP address to the UE.

Then, in step S2022", the UE may send a data packet to the network according to the acquired internet protocol address so that a User Plane Function (UPF) entity in the network acquires the data packet. For example, the UE may send a data packet to the network according to the acquired internet protocol address so that a user plane function entity in the network participating in the establishment of the protocol data unit session acquires the data packet. In addition, the data packet is used to indicate a multicast service that the user device wants to activate. The destination address of the data packet is or the protocol part of the data packet comprises the multicast address of the multicast service. For example, after step S3021", the UE may send an IGMP Join packet to the network with the assigned IP address after completing the PDU session establishment. When IGMP version 1 or 2 is employed, the destination IP address of the IGMP Join packet may be the multicast address of the multicast service. When IGMP version 3 is employed, the IGMP protocol portion of the IGMP Join packet may include the multicast address of the multicast service.

Then, in step S2023", the UE may obtain a first identity, a second identity and a multicast address from the session management function entity.

Specifically, after step S2022", the SMF entity may obtain, from the above-mentioned user plane function entity, a multicast address of a multicast service to be activated by the user equipment. For example, the UPF entity may be configured according to a packet detection rule (Packet Dection Rule, PDR) of the SMF entity, and report a multicast address corresponding to the IGMP Join packet to the SMF entity after detecting the IGMP Join packet (e.g., report the multicast address corresponding to the IGMP Join packet through an N4 session report message).

The SMF entity may then decide to instruct the user device to activate the multicast service. When the SMF entity decides to instruct the user device to activate the multicast service, the SMF entity may send a request to the user device for instructing the user device to activate the multicast service, wherein the request to instruct the user device to activate the multicast service includes a first identification, a second identification, and a multicast address of the multicast service corresponding to the multicast service to be activated by the user device. For example, the SMF entity may send a request to the user device via an access and mobility management function for instructing the user device to activate the multicast service.

For example, the SMF entity may send a message to the AMF entity over the Namf interface, which may be denoted as Namf _communication_n1MESSAGETRANSFER, for N1 interface related message transmissions communicated over the Namf interface. The message may include a request for instructing the user device to activate the multicast service. For example, the request for instructing the user equipment to activate the multicast service may be information for requesting MBS UE Context activation to instruct the UE to activate the multicast service. The information may include S-nsai, DNN corresponding to the multicast service that the user device is to activate and a multicast address for the multicast service, and may be represented as Request MBS UE Context Activation. In addition, "Request MBS UE Context Activation" described herein may be encapsulated in the particular format described above (e.g., N1 MBS SM Container).

The AMF entity may then send a downlink NAS transport message associated with the N2 interface to the RAN over the N2 interface. The downlink NAS transport message related to the N2 interface may be denoted as N2 downlink NAS Transport. The downlink NAS Transport message related to the N2 interface may include a downlink NAS Transport (DL NAS Transport) message, which may include "Request MBS UE Context Activation" encapsulated using the N1 MBS SM Container described above. Through the downlink NAS Transport message related to the N2 interface, the AMF entity may instruct the RAN to directly send a DL NAS Transport message to the UE.

The RAN may then send the DL NAS Transport message described above to the UE. Accordingly, the UE may obtain a first identity, a second identity and a multicast address from the SMF entity via DL NAS Transport message.

After step S2023", in step S2024", the UE may determine whether the acquired first identity is identical to the determined first identity, whether the acquired second identity is identical to the determined second identity, and whether the acquired multicast address is identical to the multicast address of the multicast service. For example, the UE may determine whether the multicast address in "Request MBS UE Context Activation" encapsulated using the N1 MBS SM Container is the same as the multicast address of the multicast service that the UE wants to activate, and whether the S-nsai, DNN in "Request MBS UE Context Activation" encapsulated using the N1 MBS SM Container is the same as the S-nsai, DNN at the time of establishing the PDU session, according to the DL NAS Transport message received from the RAN.

When the UE determines in step S2024″ that the acquired first identity is different from the determined first identity and/or the acquired second identity is different from the determined second identity and/or the acquired multicast address is different from the multicast address of the multicast service, the UE cannot activate the multicast service. In contrast, when the UE determines in step S2024″ that the acquired first identity is identical to the determined first identity, the acquired second identity is identical to the determined second identity, and the acquired multicast address is identical to the multicast address of the multicast service, the UE may activate the multicast service.

The UE may perform step S2025", step S2026", and step S2027 "to activate the multicast service. Specifically, in step S2025", the UE may determine a third identification, where the third identification is used to identify a user equipment multicast service context established for activating the multicast service. Then, in step S2026", the UE may send a request for activating the user equipment multicast service context to the session management function entity, the request for activating the user equipment multicast service context including the third identification and the multicast address of the multicast service. Then, in step S2027", the UE may receive a response from the session management function entity to the request for activating the user device multicast service context, the response including a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated.

The steps S2025", S2026" and S2027 "are similar to the steps S2021', S2022' and S2023' described above, respectively, and are not repeated here.

Returning to fig. 2, in step S203, the user device receives service data corresponding to the multicast service. For example, when the user device activates the multicast service and a multicast service session corresponding to the multicast service is successfully started, the AF entity may transmit multicast service data (e.g., multicast service data packets) having a destination IP address that is a multicast address of the multicast service to the downstream UPF entity. The UPF entity then sends the multicast traffic data to the RAN. The RAN may then send multicast traffic data to the UE via the resources allocated to the UE.

According to the method performed by the user device according to the embodiments of the present disclosure, the user device may determine an activation manner for activating the multicast service and activate the multicast service according to the determined activation manner and at least through a session management function entity in the network, thereby optimizing or being compatible with a conventional procedure for activating the multicast service. In addition, in the process of activating the multicast service, a multicast service session corresponding to the multicast service is started, so that a user plane corresponding to the multicast service is established in the process of activating the multicast service.

The method performed by the SMF entity will be described below in connection with fig. 4-5, where fig. 4 is a flowchart of a method performed by the session management function entity when the user device activates multicast traffic according to a first activation manner according to an embodiment of the present disclosure, and fig. 5 is a flowchart of a method performed by the session management function entity when the user device activates multicast traffic according to a second activation manner according to an embodiment of the present disclosure.

First, a method 400 performed by a session management function entity when a user device activates multicast traffic according to a first activation manner is described in connection with fig. 4. As shown in fig. 4, in step S401, a request for activating a user device multicast service context is received from a user device, the user device multicast service context being established by the user device for activating the multicast service, the request for activating the user device multicast service context including the third identification and a multicast address of the multicast service, the third identification being used for identifying the user device multicast service context.

Specifically, first, the UE may send an uplink NAS Transport (UL NAS Transport) message to the AMF entity, where the UL NAS Transport message includes at least three cells, a first cell is a first identifier corresponding to the multicast service, a second cell is a second identifier corresponding to the multicast service, a third cell is a request for activating an MBS UE Context, and the request for activating the MBS UE Context includes a third identifier corresponding to the multicast service and a multicast address of the multicast service. In an example where the first identity is S-NSSAI, the second identity is DNN, and the third identity is MBS UE Context ID, the UL NAS Transport message sent by the UE to the AMF entity may include three cells, where the first cell is S-NSSAI corresponding to the multicast service, the second cell is DNN corresponding to the multicast service, and the third cell is a request for activating MBS UE Context, where the request for activating MBS UE Context includes MBS UE Context ID corresponding to the multicast service and a multicast address of the multicast service.

Furthermore, according to one example of the present disclosure, the SMF entity may record the identity of the serving base station of the user device in the user device multicast service context so that the SMF entity obtains the identities of the serving base stations of all user devices that activate the multicast service through the SMF entity for use in establishing the user plane of the MBS session. For example, the SMF entity may record the received RAN ID in the MBS UE Context of the UE.

Returning to fig. 4, after step S401, in step S402, the SMF entity determines a response to the request for activating a user device multicast service context, wherein the response includes a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated. For example, the SMF entity determines a fourth identifier corresponding to the multicast service according to at least the first identifier, the second identifier, and the multicast address of the multicast service, where the fourth identifier is an identifier allocated by the application functional entity to the multicast service.

According to one example of the present disclosure, step S402 may include three sub-steps, step S4021, step S4022, and step S4023, respectively.

Specifically, in step S4021, the SMF entity may determine whether the user device can use the multicast service. For example, the SMF entity may obtain subscription data of the UE from a Unified data management (Unified DATA MANAGEMENT, UDM) entity to determine whether the UE has subscribed to the multicast service. If the UE signs up for the multicast service, the SMF entity may determine that the UE is able to use the multicast service. If the UE is not subscribed to the multicast service, the SMF entity may determine that the UE cannot use the multicast service.

When the SMF entity determines in step S4021 that the UE can use the multicast service, the SMF entity may perform step S4022. In step S4022, the SMF entity sends a notification to the application functional entity, where the notification is a notification of the multicast service authorization request. The notification comprises at least the first identification, the second identification, a multicast address of the multicast service, and an identification of the session management function entity. The "identification of the session management function entity" is herein used to facilitate the application function entity to acquire the session management function entity involved in activating the multicast service by all user apparatuses to activate the multicast service, so as to be used when a user plane corresponding to the multicast service is subsequently established.

Specifically, the SMF entity may send the notification directly to the application function entity. For example, the SMF entity may determine the corresponding AF entity according to the first identifier, the second identifier, and the multicast address of the multicast service. The SMF entity may then send a notification to the determined AF entity. The notification may include the first identification, the second identification, a private identification and a public identification of the user device (e.g., a common public subscription identifier (Generic Public Subscription Identifier, GPSI)), a multicast address of the multicast service, and an identification of the session management function entity (e.g., an SMF ID of the SMF entity and its IP address).

Alternatively, the SMF entity may send the notification to the application function entity via a network open function entity.

In an example where the SMF entity sends a notification to the application function entity via the network opening function entity, first, the SMF entity may send a notification to the network opening function entity, which may include the first identification, the second identification, a private identification and a public identification of the user device (e.g., a common public subscription identifier (Generic Public Subscription Identifier, GPSI)), a multicast address of the multicast service, an identification of the session management function entity, and an identification of the application function entity (e.g., an AF ID of an AF entity determined by the SMF entity), so that the network opening function entity sends another notification to the application function entity according to the identification of the application function entity. The further notification may comprise a first identification, said second identification, a private and public identification of said user device, a multicast address of said multicast service, and an identification of said session management function node entity.

In the example of the first identifier S-NSSAI, the second identifier DNN, the dedicated identifier SUPI of the UE, the public identifier GPSI of the UE, the identifier SMF ID of the session management function entity, and the identifier AF ID of the application function entity, the SMF entity may send a notification of the MBS authorization request to the NEF entity through the Nsmf interface, which may be denoted as Nsmf _ MBS AuthorizationRequest Notify, and which may include S-NSSAI and DNN corresponding to the multicast service, the dedicated identifier SUPI of the UE, the public identifier GPSI of the UE, the multicast address of the multicast service, the SMF ID, and the AF ID. In addition, the notification may also include other information, such as information related to the UE location, such as one or more of a cell global identifier (Cell Global Identifier, CGI), tracking area identifier (TRACKING AREA IDENTITY, TAI), globally Unique AMF identifier (global unit AMF IDENTIFIER, GUAMI), etc.

Then, after receiving the notification, the network open function entity may determine the application function entity according to the identifier of the application function entity and send another notification to the application function entity. The further notification may comprise the first identification, the second identification, a public identification of the user device, a multicast address of the multicast service, and an identification of the session management function entity.

In the example of the first identifier S-NSSAI, the second identifier DNN, the UE ' S dedicated identifier SUPI, the UE ' S public identifier GPSI, the session management function entity ' S identifier SMF ID, and the application function entity ' S identifier AF ID, the NEF entity may send a notification of the MBS authorization request to the corresponding AF entity according to the AF ID through the Nnef interface, which may be denoted as Nnef _ MBSAuthorizationRequest Notify, and which may include S-NSSAI and DNN corresponding to the multicast service, the UE ' S public identifier GPSI, the multicast address of the multicast service, and SMFID. In addition, the notification may also include other information, such as information related to the UE location, such as one or more of CGI, TAI, GUAMI, etc.

After step S4022, the AF entity may record the received SMF ID for use in establishing the user plane of the MBS session. In addition, the AF entity may also determine a fourth identification corresponding to the multicast service. The fourth identification described herein may be a temporary mobile group identification (Tempory Mobile Group Identify, TMGI) assigned by the AF entity to the multicast service activated based on the multicast address.

The fourth identification may be a TMGI when the AF entity receives a message from the NEF entity. Accordingly, the AF entity may feed back response information of notification of the MBS authorization request to the NEF entity through the Nnef interface, which may be denoted as Nnef _ MBS AuthorizationRequest Notify Response, and which may include a TMGI corresponding to the multicast service. Then, the NEF entity may feedback response information, which may be denoted as Nsmf _ MBS AuthorizationRequest Notify Response, of the notification of the MBS authorization request to the SMF entity through the Nsmf interface, and the response information may include a TMGI corresponding to the multicast service.

Accordingly, in step S4023, the SMF entity may receive a response to the notification in step S4022 from the application function entity, where the response to the notification includes a fourth identifier corresponding to the multicast service, thereby acquiring the fourth identifier corresponding to the multicast service from the application function entity. In an example where the fourth identity is a TMGI, the SMF entity may obtain the TMGI corresponding to the multicast service directly from the AF entity, or the SMF entity may obtain the TMGI corresponding to the multicast service from the AF entity via the NEF entity.

It is to be appreciated that when the multicast service is not successfully authorized by the AF entity, the response information fed back by the AF entity does not include the TMGI and may include the cause of the failure.

Furthermore, it is to be appreciated that in the communication of the NEF entity with the AF entity described above, the information sent from the NEF entity to the AF entity may comprise a NEF transaction identity (NEF Transaction ID), and the information fed back by the AF entity to the NEF entity for this information may also comprise the NEF transaction identity.

Returning to fig. 4, in step S403, the SMF entity obtains a fifth identifier corresponding to the multicast service, where the fifth identifier is used to identify a start of a multicast service session corresponding to the multicast service. The fifth identification may be a multicast service session start identifier (Session Start Indicator) to start the multicast service session, thereby establishing a user plane corresponding to the multicast service during activation of the multicast service. Step S403 may be performed simultaneously with step S402 described above, or step S403 may be performed after step S402.

In an example where step S403 is performed concurrently with step S402 described above, step S403 may be performed concurrently with sub-step S4023 of step S402 described above. That is, when the SMF entity receives a response to the request for activating the user device multicast service context from the application function entity in step S4023, the SMF entity may further receive a fifth identification corresponding to the multicast service from the application function entity. For example, the SMF entity may receive a response message from the application function entity, and the response message includes both the response to the request for activating the user device multicast service context and a fifth identification corresponding to the multicast service.

According to one example of the present disclosure, the SMF entity may receive a response to the request for activating the user device multicast service context and a fifth identification corresponding to the multicast service directly from the application function entity. For example, when the AF entity receives a message from the SMF entity, the fourth identification, which is a response to the request for activating the user device multicast service context, may be a TMGI. Accordingly, the AF entity may feed back response information of notification of the MBS authorization request to the SMF entity through the Nsmf interface, which may be denoted as Nsmf _ MBS AuthorizationRequest Notify Response, and which may include a TMGI corresponding to the multicast service and a multicast service session start identifier.

According to another example of the present disclosure, the SMF entity may receive a response to the request for activating the user device multicast service context and a fifth identification corresponding to the multicast service from the application function entity via the network opening function entity. For example, when the AF entity receives a message from the NEF entity, the fourth identification, which is a response to the request for activating the user device multicast service context, may be a TMGI. Accordingly, the AF entity may feed back response information of notification of the MBS authorization request to the NEF entity through the Nnef interface, which may be denoted as Nnef _ MBS AuthorizationRequest Notify Response, and which may include a TMGI corresponding to the multicast service and a multicast service session start identifier. Then, the NEF entity may feedback response information, which may be denoted as Nsmf _ MBS AuthorizationRequest Notify Response, of the notification of the MBS authorization request to the SMF entity through the Nsmf interface, and the response information may include the TMGI corresponding to the multicast service and the multicast service session start identifier.

After step S403, the SMF entity may create MBS UE Context for the UE based on the above-described multicast address, and then may feedback a response message to the AMF entity, which may be as a response of Nsmf _ MBSSession _ CreateMBSUEContext Request described above. The response information may be an acknowledgement to Nsmf _ MBSSession _ CreateMBSUEContext Request described above, which may be denoted Nsmf _ MBSSession _ CreateMBSUEContext Response.

It is to be appreciated that in the conventional user plane setup procedure, after the SMF entity feeds back the above described response information (Nsmf _ MBSSession _ CreateMBSUEContext Respons) to the AMF entity, the SMF entity directly sends information related to the multicast service session to the AMF entity, e.g. sends TMGIs corresponding to the multicast service, quality of service flow identities and quality of service configuration files corresponding to the respective data flows, the tunnel multicast address, the sixth identity, etc. by Namf _communication_n1n2MESSAGETRANSFER messages. However, in the present disclosure, since the SMF entity acquires the multicast service session start identifier corresponding to the multicast service from the application function entity in the above-described step S403, the SMF entity does not need to directly transmit information related to the multicast service session to the AMF entity according to a conventional user plane setup procedure, but transmits information related to the multicast service session to the AMF entity after receiving the message of the PCF entity.

Then, in step S404, the SMF entity performs the multicast service session and sends a response to the request for activating the user device multicast service context to the user device. Step S404 may include 8 substeps, step S4041 to step S4048, respectively.

First, in step S4041, the SMF entity receives a first request from a policy control function entity, wherein the first request is for requesting the start of a multicast service Session (MBS Session). The first request may include at least a first identification of the user device, a fourth identification corresponding to a multicast service, a quality of service rule for at least one data flow corresponding to the multicast service, and an identification of the multicast service session. In addition, the first request may also include other information, such as an expected duration of the multicast service session (ESTIMATED SESSION DURATION), and a data transmission time of the multicast service (time to MBS DATA TRANSFER). Through step S4041, policy Control AND CHARGING (PCC) technology is applied to transmission of multicast service data, so that the combination of transmission of PCC and multicast service data is achieved.

The first request includes a first identification of the user equipment (e.g., a dedicated identification SUPI) to indicate that this is an operation performed for a particular one of the UEs. Furthermore, the first identity of the user device may be determined by the network opening function entity based on the second identity of the user device. For example, in an example where the first identity is a private identity (SUPI) and the second identity is a generic identity (GPSI), the network opening function entity may determine the private identity of the user device from the generic identity of the user device.

According to one example of the present disclosure, the fourth identification in the first request may be an identification assigned to the multicast service by the application function entity, such as the TMGI described above. The identification of the multicast traffic session in the first request may be an ID of the multicast traffic session.

Further, according to one example of the present disclosure, a PCF entity corresponding to an SMF entity may send a first request to the SMF entity over a Nsmf interface to request the start of a multicast traffic session. The first request may be denoted Nsmf _ MBS SessionStart Request.

Further, according to one example of the present disclosure, the first request in step S4041 is determined by the policy control function entity according to a second request received from a network opening function entity or an application function entity, the second request being for the network opening function entity or the application function entity to request the start of a multicast traffic session from the policy control function entity. The second request may include at least a first identification of the user device, the fourth identification, an identification of the session management function entity, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, and an identification of the multicast service session. In addition, the second request may also include other information, such as the expected duration of the multicast service session, and the data transmission time of the multicast service.

The second request includes a first identification of the user equipment (e.g., a dedicated identification SUPI) to indicate that this is an operation performed for a particular one of the UEs.

In an example where the first request is determined by the policy control function entity based on a second request received from the application function entity, the AF entity may send the second request to the PCF entity over the Npcf interface to request the start of the multicast traffic session. The second request may be denoted Npcf _ MBS SessionStart Request.

Further, in an example where the first request is determined by the policy control function entity from a second request received from the network opening function entity, the NEF entity may send the second request to the PCF entity over the Npcf interface to request the start of the multicast traffic session. The second request may be denoted Npcf _ MBS SessionStart Request.

In an example where the first request is determined by the policy control function from a second request received from a network opening function, the second request is determined by the network opening function from a third request received from an application function, the third request being for the application function to request a start of a multicast traffic session from the network opening function. The third request may include at least a second identification of the user device, the fourth identification, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, and an identification of the multicast service session. In addition, the third request may also include other information, such as the expected duration of the multicast service session, and the data transmission time of the multicast service.

The third request includes a second identification of the user equipment (e.g., a general identification GPSI) to indicate that this is an operation performed for a particular one of the UEs.

In this example, the AF entity may send a third request to the NEF entity over the Nnef interface to request the start of the multicast service session. The third request may be denoted Nnef _ MBS SessionStart Request.

Exemplary flows of the AF entity sending the third request to the NEF entity, the NEF entity sending the second request to the PCF entity, and the PCF entity sending the first request to the SMF entity are given below.

Specifically, first, the AF entity sends a third request (Nnef _ MBS SessionStart Request) to the NEF entity, which may include the GPSI of the user equipment, the TMGI corresponding to the multicast service, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, an ID of a multicast service session, an expected duration of the multicast service session, and a data transmission time of the multicast service.

In examples where there are multiple PCF entities and each PCF entity corresponds to one or more SMF entities, the PCF entity is determined by the NEF entity or the AF entity based on the identity of the SMF entity. For example, the NEF entity or the AF entity may determine an identification (SMF ID) of the SMF entity according to the GPSI of the user equipment and the TMGI corresponding to the multicast service, and then may determine the PCF entity corresponding to the SMF ID based on the SMF ID.

The NEF entity may then send a second request (Npcf _ MBS SessionStart Request) to the respective PCF entity according to the SMF ID, the second request may include the SUPI of the user device, the TMGI corresponding to the multicast service, one SMF ID, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, an ID of the multicast service session, an expected duration of the multicast service session, and a data transmission time of the multicast service.

Finally, the PCF entity may send a first request (Nsmf _ MBS SessionStart Request) to the respective SMF entity according to the SMF ID, the first request may include the SUPI of the user equipment, the TMGI corresponding to the multicast service, the quality of service rule of the at least one data flow, the ID of the multicast service session, the expected duration of the multicast service session, and the data transmission time of the multicast service.

Furthermore, the "information of at least one data stream corresponding to the multicast service" in the above-described third request may be information of all data streams to be used for transmitting the multicast service. The data stream here may be an IP stream. In this case, the information of each data flow may be determined by an IP triplet. The IP triplet may indicate that the destination IP address of the IP flow is a multicast address, a destination port, a communication protocol employed (e.g., UDP protocol). It is to be appreciated that in other examples of the present disclosure, the information for each data stream may be determined by an IP five tuple, or may be determined by other triples, as the present disclosure is not limited in this regard.

Further, the "quality of service Requirement of the at least one data flow" in the third request described above may include a quality of service Requirement (QoS Requirement) corresponding to each data flow. The quality of service requirements for each data flow may include one or more of a QoS class identifier (QoS CLASS IDENTIFIER, QCI), an assigned reservation Priority (Allocation Retention Priority, ARP), a Priority Level (Priority Level), and the like. Further, the quality of service requirement of each data stream may be used to generate a quality of service rule for each data stream in the first request. Specific generation methods may adopt some existing generation methods, and the disclosure is not limited thereto.

In addition, any of the first, second, and third requests described above may further include an aggregate maximum rate corresponding to the multicast traffic. The aggregate maximum rate may have only the value in the downlink direction and not the value in the uplink direction. Alternatively, the aggregate maximum rate may have both a value in the downlink direction and a value in the uplink direction. The aggregate maximum rate may be an aggregate maximum bit rate (AGGREGATE MAXIMUM BIT RATE, AMBR).

After step S4041, in step S4042, the SMF entity may generate a quality of service flow identifier (QoS Flow Identity, QFI), a quality of service Profile (QoS Profile), and a quality of service execution Rule (QER) corresponding to each data flow according to a quality of service Rule of each data flow of at least one data flow corresponding to the multicast service. In the present disclosure, the quality of service flow identity corresponding to each data flow may also be referred to as a quality of service flow identity (MBS QFI) of the multicast service. Further, the quality of service enforcement rules described herein may be similar to conventional N4 QER rules.

Then, in step S4043, the SMF entity may select a user plane functional entity according to said fourth identity. In the example where the fourth identifier is a TMGI, the SMF entity may determine a corresponding MBS UE Context according to the TMGI, and obtain the S-nsai, DNN, and the multicast address included in the MBSUE Context according to the determined MBS UE Context. The SMF entity may then select a UPF entity from the plurality of UPF entities based on the acquired S-NSSAI, DNN, and multicast address.

It is to be appreciated that if a UPF entity has been previously allocated, the SMF entity may not perform step S4043 described above.

The SMF entity may then send a fourth request to the selected user plane functional entity in step S4044, wherein the fourth request is for establishing transmission resources of the multicast service session. The fourth request includes at least a multicast address of the multicast service, a quality of service enforcement rule for at least one data flow corresponding to the multicast service, and an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service. For example, the SMF entity may send a request for requesting MBS session establishment to the selected UPF entity through the N4 interface, which may be denoted as N4 MBS Session Establishment Request.

Then, in step S4045, the SMF entity may obtain a response to the fourth request from the selected user plane functional entity, where the response to the fourth request includes a tunnel multicast address allocated by the selected user plane functional entity for transmitting traffic data corresponding to the multicast traffic, and a sixth identification corresponding to the tunnel multicast address, where the tunnel multicast address is used for multicast tunneling between network entities (e.g., multicast tunneling between the UPF entity and the RAN), and the sixth identification is used for identifying a transport tunnel (e.g., a GTP-related transport tunnel) for the multicast traffic.

For example, the UPF entity may establish a GTP user plane tunneling tree from the UPF entity to the RAN according to a multicast routing protocol in accordance with the received request to transport data (e.g., traffic data corresponding to the multicast/broadcast traffic) to be sent by the UPF entity to the RAN in a tree-like GTP user plane tunnel. The UPF entity may then assign a tunnel multicast address for transmitting traffic data corresponding to the multicast/broadcast traffic. Specifically, the UPF entity may allocate a multicast address of the GTP user plane tunnel through the N3 interface for the multicast/broadcast service, and take the multicast address of the allocated GTP user plane tunnel as a tunnel multicast address. The "tunnel multicast address" described herein may also be referred to as a transport layer IP multicast address (Transport IP Multicast Address). The UPF entity can then assign a sixth identification, e.g., common tunnel endpoint identification (Common-Tunnel End point ID, C-TEID), to the multicast/broadcast service.

After the UPF entity allocates the tunnel multicast address and the sixth identifier for the multicast service, the UPF entity may send response information to the SMF entity through the N4 interface in response to the request for requesting MBS session establishment sent by the SMF entity to the UPF entity as described above. The response information may include a tunnel multicast address corresponding to the multicast service and a sixth identification corresponding to the multicast service. The response information may be represented as N4 MBS Session Establishment Response.

Accordingly, the SMF entity may obtain a tunnel multicast address corresponding to the multicast service from the selected UPF entity and a sixth identification corresponding to the multicast service from the selected user plane function entity. The SMF entity may then record the tunnel multicast address and the sixth identification in respective user device multicast service contexts in which the multicast service has been activated.

It should be appreciated that in this disclosure, the tunnel multicast address assigned by the UPF entity and the sixth identification uniquely correspond to the multicast address of the multicast service.

It should also be appreciated that in this disclosure, the tunnel multicast address allocated by the UPF entity may be regarded as a Core Network (CN) allocated tunnel multicast address, and the sixth identifier allocated by the UPF entity may be regarded as a CN allocated sixth identifier.

It is to be appreciated that in the present disclosure, transmission channels of data streams corresponding to different multicast services may be distinguished by different sixth identifications, while a plurality of data streams corresponding to each multicast service may be distinguished by the QFI described above.

Furthermore, in the present disclosure, the SMF entity may record at least the tunnel multicast address allocated by the UPF entity and the sixth identification in respective user device multicast service contexts in which the multicast service has been activated. For example, the SMF entity may record the identification of the PCF entity involved in the above procedure (PCF ID), the identification of the UPF entity involved (UPF ID), and the tunnel multicast address and C-TEID allocated by the UPF entity to the respective user equipment multicast service Context (MBS UE Context) that has activated the multicast service. If a UPF entity has been previously allocated and the UPF entity has also been allocated a tunnel multicast address and a C-TEID, only the tunnel multicast address and the C-TEID allocated by the UPF entity may be recorded into a user equipment multicast service Context (MBS UE Context) of the UE.

Furthermore, it is to be appreciated that a UPF entity may also establish a transport tree from an AF entity to the UPF entity. That is, the transmission from the AF entity to the UPF entity may also take the form of transport layer multicasting. Alternatively, multicast transmission from the AF entity to the UPF entity may also be implemented by routing means (e.g. routers) between the AF entity and the UPF entity.

Further, according to one example of the present disclosure, steps S4043 to S4045 may also be replaced with steps S4043 'to S4045' (not shown in the figure). In step S4043', the SMF entity may select a user plane functional entity according to said fourth identity. Then, in step S4044', the SMF entity may send a fourth request to the selected user plane functional entity, wherein the fourth request is for establishing transmission resources of the multicast service session, the fourth request includes a tunnel multicast address allocated by the session management functional entity for transmitting service data corresponding to the multicast service, and a sixth identification corresponding to the tunnel multicast address, wherein the tunnel multicast address is used for multicast tunneling between network entities, and the sixth identification is used for identifying a transmission tunnel of the multicast service. Then, in step S4045', the SMF entity may obtain a response to the fourth request from the selected user plane function entity, wherein the response to the fourth request is an acknowledgement of the fourth request. That is, the tunnel multicast address described herein may be assigned by the SMF entity and notified by the SMF entity to the selected UPF entity.

In addition, in this example, the fourth request may also include a multicast address of the multicast service, a quality of service enforcement rule for at least one data flow corresponding to the multicast service, and an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service. In addition, the SMF entity may similarly record its assigned tunnel multicast address and the sixth identification in the respective user device multicast service context that has activated the multicast service.

Then, in step S4046, the SMF entity may send first information to the access and mobility management function entity, wherein the first information includes the response and information related to the multicast service session, so that the access and mobility management function entity sends a fifth request to a corresponding serving base station according to the information related to the multicast service session, and sends the response to the user equipment via the corresponding serving base station, wherein the fifth request is for requesting the start of the multicast service session. The "information related to the multicast service session" described herein includes at least the fourth identifier, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a quality of service flow identifier and a quality of service profile corresponding to each data flow, the tunnel multicast address, and the sixth identifier.

Accordingly, the UE is able to obtain a response from the session management function entity to the request for activating the user device multicast service context.

One specific implementation of step S4046 is given below.

First, the SMF entity may send first information to the AMF entity through the Namf interface. The first information may be a message transmission related to the N1 interface and the N2 interface, which may be denoted as Namf _communication_n1n MESSAGETRANSFER, communicated over the Namf interface. The first information may include "the response to the request for activating the user equipment multicast service Context" described above in response to the request for activating the MBS UE Context sent by the AMF entity to the SMF entity described above in connection with step S3022'. The "response to the request for activating the user equipment multicast service Context" may include a TMGI corresponding to the multicast service and may be expressed as a response activating MBS UE Context (Activate MBS UE Context Response). The SMF entity may encapsulate the "response to activate MBS UE Context" using the N1 MBS SM Context described above. In addition, the first information may further include a TMGI corresponding to the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a CN N3 tunnel multicast address corresponding to the multicast service, and a CN N3C-TEID. The SMF entity may encapsulate the TMGI corresponding to the multicast service, the quality of service flow identification and the quality of service profile corresponding to each data flow of the multicast service, the CN N3 tunnel multicast address corresponding to the multicast service, and the CN N3C-TEID using the N2 MBS SM Container described above.

The AMF entity may then send a fifth request, which may be denoted as N2 MBS Session Start Request, to the RAN over the N2 interface for requesting the start of the multicast service session. The fifth request may include a downlink NAS Transport (DL NAS Transport) message, one cell of which is the response of activating MBS UE Context (Activate MBS UE Context Response) encapsulated using N1 MBS SM Context described above. Through the downlink NAS Transport message, the AMF entity may instruct the RAN to send the DLNAS Transport message directly to the UE. In addition, the fifth request may further include a TMGI corresponding to the multicast service, a multicast address of the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a CN N3 tunnel multicast address corresponding to the multicast service, and a CN N3C-TEID.

The RAN may then send the DL NAS Transport message described above to the UE through RRC signaling. Accordingly, the UE may acquire the fourth identifier corresponding to the multicast service through the DL NAS Transport message. In an example where the fourth identity is a TMGI, the UE may acquire the TMGI corresponding to the multicast service through a DL NAS Transport message.

Through the above step S4046, not only the user plane corresponding to the multicast service is established, but also the UE activates the multicast service.

After step S4046, the serving base station of the UE may send a response to the fifth request to the access and mobility management function entity. For example, the RAN may send a response to the fifth request to the AMF entity over the N2 interface in response to the fifth request for requesting MBS session initiation sent by the AMF entity to the RAN as described above. The response may be an acknowledgement of N2 MBS Session Start Request, described above, sent by the AMF entity to the RAN, and may be denoted as N2 MBS Session Start Response.

The serving base station may then allocate resources for transmitting multicast traffic data to the UEs it serves to support data streams with different quality of service requirements. Accordingly, the UE may receive multicast service data through the allocated resources.

The serving base station may then join the transport group corresponding to the tunnel multicast address described above (e.g., CN N3 tunnel multicast address) to receive multicast traffic data from the UPF entity. That is, a transmission tree from the UPF entity to the serving base station may be established to transmit data (e.g., multicast traffic data) to be transmitted by the UPF entity to the serving base station in a tree-like manner.

It is to be appreciated that if the serving base station has allocated resources corresponding to the multicast service for the UE it serves, then the serving base station need not allocate resources for transmitting multicast service data again for the UE and need not join the transmission group corresponding to the tunnel multicast address.

The AMF entity may then send a notification message to the SMF entity to notify the first information sent by the SMF entity to the AMF entity as described in step S4046 above. For example, the AMF entity may send the notification information to the SMF entity over the Namf interface. The notification information may be an acknowledgement of the first information sent by the SMF entity to the AMF entity described in the above step S4046. The notification information may be MBS message transmission related to the N2 interface, which may be denoted as Namf _communication_n2MBSMessageNotify, communicated over the Namf interface. Accordingly, in step S4047, the SMF entity receives notification information for the first information from the AMF entity.

Then, in step S4048, the SMF entity may send a response message to the PCF entity via the Nsmf interface in response to the first request sent by the PCF entity to the SMF entity described in step S4041. For example, the response information may be an acknowledgement of "Nsmf _ MBS SessionStart Request" described in step S4041 as being sent by the PCF entity to the SMF entity, and may be denoted as Nsmf _ MBS SessionStart Response.

Further, after step S4048, the PCF entity may send a response message to the NEF entity via the Npcf interface in response to the second request sent by the NEF entity to the PCF entity described in step S4041. For example, the response information may be an acknowledgement of "Npcf _ MBS SessionStartRequest" described in step S4041 as being sent by the NEF entity to the PCF entity, and may be denoted as Npcf _ MBS SessionStart Response.

Then, the NEF entity may send a response message to the AF entity through the Nnef interface in response to the third request sent by the AF entity to the NEF entity described in step S4041 above. For example, the NEF entity may send the response information to the AF entity through the Nnef interface, and the response information may be denoted as Nnef _ MBS SessionStart Response.

Up to this point, the user plane corresponding to the multicast service has been established successfully. This means that the multicast traffic can start. For example, the AF entity may send multicast service data (e.g., multicast service packets) with a destination IP address that is the multicast address of the multicast service to a downstream UPF entity. The UPF entity may then send multicast traffic data to the RAN by the transport layer multicast method described above. The RAN may then send multicast traffic data to the UE via the resources allocated to the UE.

According to the method executed by the session management function entity in the embodiment of the disclosure, in the process of activating the multicast service, the session management function entity can receive the third identifier corresponding to the multicast service to be activated by the user device and the multicast address of the multicast service from the user device, and determine the fourth identifier corresponding to the multicast service and the fifth identifier at least according to the information, so that the multicast service session corresponding to the multicast service can be conducted according to the fifth identifier to establish the user plane corresponding to the multicast service, and the fourth identifier is fed back to the user device so that the user device can activate the multicast service, thereby realizing the establishment of the user plane corresponding to the multicast service in the process of activating the multicast service.

A method 500 performed by the session management function entity when the user device activates multicast traffic according to the second activation manner is described below in connection with fig. 5.

As shown in fig. 5, in step S501, the SMF entity may establish a protocol data unit session and assign an internet protocol address (IP address) to the user device. For example, in an example where the first identity is S-NSSAI and the second identity is DNN, the UE may send a PDU session establishment request to the network according to S-NSSAI and DNN corresponding to the multicast service, which may include S-NSSAI and DNN corresponding to the multicast service. The AMF entity may then select one SMF entity from the plurality of SMF entities based on S-NSSAI and DNN corresponding to the multicast service. The selected SMF entity may then select a UPF entity from a plurality of UPF entities and assign an IP address to the UE.

Then, in step S502, a multicast address of a multicast service to be activated by the user equipment is obtained from a user plane function entity participating in the establishment of the protocol data unit session, wherein the multicast address is obtained after the user equipment transmits a data packet to a network including the user plane function entity according to the internet protocol address, wherein the data packet is used for indicating the multicast service to be activated by the user equipment, and a destination address of the data packet is the multicast address of the multicast service or a protocol part of the data packet includes the multicast address of the multicast service.

Specifically, the UE may send a data packet to the network according to the acquired IP address so that a user plane function entity in the network acquires the data packet. For example, the UE may send a data packet to the network according to the acquired internet protocol address so that a user plane function entity in the network participating in the establishment of the protocol data unit session acquires the data packet. In addition, the data packet is used to indicate a multicast service that the user device wants to activate. The destination address of the data packet is or the protocol part of the data packet comprises the multicast address of the multicast service. For example, the UE may send IGMP Join packets to the network with the assigned IP address after completing PDU session establishment. When IGMP version 1 or 2 is employed, the destination IP address of the IGMP Join packet may be the multicast address of the multicast service. When IGMP version 3 is employed, the IGMP protocol portion of the IGMP Join packet may include the multicast address of the multicast service.

Accordingly, the SMF entity may obtain, from the above-mentioned user plane function entity, a multicast address of a multicast service to be activated by the user equipment. For example, the UPF entity may be configured according to a packet detection rule (Packet Dection Rule, PDR) of the SMF entity, and report a multicast address corresponding to the IGMP Join packet to the SMF entity after detecting the IGMP Join packet (e.g., report the multicast address corresponding to the IGMP Join packet through an N4 session report message).

When the SMF entity decides to instruct the user equipment to activate the multicast service, the SMF entity may perform step S503. In step S503, the SMF entity may send a request for instructing the user device to activate the multicast service to the user device, where the request for instructing the user device to activate the multicast service includes a first identifier corresponding to a multicast service to be activated by the user device, a second identifier, and a multicast address of the multicast service. For example, the SMF entity may send a request to the user device via an access and mobility management function for instructing the user device to activate the multicast service.

For example, the SMF entity may send a message to the AMF entity over the Namf interface, which may be denoted as Namf _communication_n1MESSAGETRANSFER, for N1 interface related message transmissions communicated over the Namf interface. The message may include a request for instructing the user device to activate the multicast service. For example, the request for instructing the user equipment to activate the multicast service may be information for requesting MBS UE Context activation to instruct the UE to activate the multicast service. The information for requesting MBS UE Context activation may include S-nsai, DNN corresponding to a multicast service to be activated by the user equipment and a multicast address of the multicast service, and the information for requesting MBS UE Context activation may be denoted as Request MBS UE Context Activation. In addition, "Request MBS UE Context Activation" described herein may be encapsulated in the particular format described above (e.g., N1 MBS SM Container).

After step S503, the AMF entity may send a downlink NAS transport message related to the N2 interface to the RAN via the N2 interface. The downlink NAS transport message related to the N2 interface may be denoted as N2 downlink NAS Transport. The downlink NAS Transport message related to the N2 interface may include a downlink NAS Transport (DL NAS Transport) message, which may include "Request MBS UE Context Activation" encapsulated using the N1 MBS SM Container described above. Through the downlink NAS Transport message related to the N2 interface, the AMF entity may instruct the RAN to directly send a DL NAS Transport message to the UE. The RAN may then send the DL NAS Transport message described above to the UE. Accordingly, the UE may obtain a first identity, a second identity and a multicast address from the SMF entity via DL NAS Transport message.

Then, after step S504, the SMF entity receives from the user device a request for activating a user device multicast service context, the user device multicast service context being established for activating the multicast service, the request for activating the user device multicast service context comprising the third identification and a multicast address of the multicast service, the third identification being used for identifying the user device multicast service context. In step S505, the SMF entity determines a response to the request for activating a user device multicast service context, wherein the response comprises a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated. In step S506, the SMF entity obtains a fifth identifier corresponding to the multicast service, where the fifth identifier is used to identify a start of a multicast service session corresponding to the multicast service. In step S507, the SMF entity performs the multicast service session and sends a response to the request for activating the user device multicast service context to the user device.

The steps S504, S505, S506 and S507 are similar to the steps S401, S402, S403 and S404 in the method 400, respectively, and are not described herein.

An exemplary flow of activating a multicast service and establishing a user plane corresponding to the multicast service in a wireless communication system according to an embodiment of the present disclosure will be described below with reference to fig. 6-7, wherein fig. 6 is an exemplary flow of activating a multicast service and establishing a user plane corresponding to the multicast service based on a first activation manner in a wireless communication system according to an embodiment of the present disclosure, and fig. 7 is an exemplary flow of activating a multicast service and establishing a user plane corresponding to the multicast service based on a second activation manner in a wireless communication system according to an embodiment of the present disclosure.

First, a specific flow of activating a multicast service and establishing a user plane corresponding to the multicast service based on a first activation manner in a wireless communication system will be described with reference to fig. 6.

As shown in fig. 6, in step1, the UE may initiate a registration procedure with the network and the AMF entity establishes a UE policy association with the PCF entity (UE Policy Association).

Then, in step 2, in the process that the AMF entity and the PCF entity establish the UE policy association, the PCF entity may provide a plurality URSP rules to the UE through the AMF entity, where each URSP rule corresponds to one multicast service and each URSP rule includes at least a multicast address of the corresponding multicast service.

Then, in step 3, the UE wants to activate a multicast service and can query the relevant URSP rule according to the multicast address of the multicast service to obtain a routing descriptor (Route Selection Descriptor), wherein the routing descriptor comprises an S-NSSAI and a DNN.

Then, in step 4, the UE decides to activate the multicast traffic in a first activation manner, i.e. a manner that optimizes the regular activation of the multicast traffic.

Then, in step 5, the UE initiates a multicast service activation procedure to the multicast address of the multicast service. The UE may assign MBS UE Context ID an MBS UE Context established for activating the multicast service. Furthermore, the UE may send an uplink non-access Transport (UL NAS Transport) message to the AMF entity, the message comprising three cells, wherein the first cell is S-NSSAI obtained in step 3, the second cell is DNN obtained in step 3, and the third cell is a request for activating MBS UE Context, the request for activating MBS UE Context comprising MBS UE Context ID corresponding to the multicast service and a multicast address of the multicast service. In addition, the UE may encapsulate a request for activating the MBS UE Context using a session management Container (N1 MBS SM Context) of the multicast service related to the N1 interface.

Then, in step 6, the AMF entity may select one SMF entity according to the received S-NSSAI and DNN, and send a request (Nsmf _ MBSSession _ CreateMBSUEContext Request) for creating MBS UE Context related to the MBS session, including S-NSSAI corresponding to the multicast service, DNN corresponding to the multicast service, the above-described "request for activating MBS UE Context" encapsulated by N1 MBS SM Container, and SUPI and GPSI of the UE and corresponding RAN ID, to the selected SMF entity through Nsmf interface. The SMF entity may record this RAN ID in the MBS UE Context of the UE.

Then, in step 7, the SMF entity may determine whether the UE may use the multicast service according to subscription data of the UE obtained from the UDM entity (interaction of the SMF entity with the UDM entity is not shown in the figure). If the UE can use the multicast service, the SMF entity can determine the AF entity based on the received S-nsai, DNN, and multicast address. The SMF entity may then first send a notification of the MBS authorization request to the NEF entity over the Nsmf interface (Nsmf _ MBS AuthorizationRequest Notify), which may include S-NSSAI and DNN corresponding to the multicast service, the UE 'S private identity SUPI, the UE' S public identity GPSI, the multicast address of the multicast service, the SMF ID, AF ID, and information about the UE location (CGI, TAI, GUAMI, etc.). The SMF ID in the notification may be recorded by the AF entity for use in setting up the user plane of the MBS session. Furthermore, the AF ID in the notification may facilitate the NEF entity to determine the corresponding AF entity.

Then, in step 8, the NEF entity may send a notification of the MBS authorization request (Nnef _ MBS AuthorizationRequest Notify) to the corresponding AF entity according to the received AF ID through the Nnef interface, which may include S-NSSAI and DNN corresponding to the multicast service, the public identity GPSI of the UE, the multicast address of the multicast service, the SMF ID, and information about the UE location (CGI, TAI, GUAMI, etc.).

Then, in step 9, the AF entity may feed back response information (Nnef _ MBS AuthorizationRequest Notify Response) of the notification of the MBS authorization request, including the TMGI corresponding to the multicast service and the multicast service session start identifier, to the NEF entity through the Nnef interface (Session Start Indicator). The multicast service session start identifier is used to perform a subsequent establishment of a user plane for the UE and corresponding to the multicast service.

Then, in step 10, the NEF entity may feed back response information (Nsmf _ MBS AuthorizationRequest Notify Response) of the notification of the MBS authorization request to the SMF entity through the Nsmf interface, and the response information may include the TMGI corresponding to the multicast service and the multicast service session start identifier.

Then, in step 11, the SMF entity may create an MBS UE Context for the UE based on the above-mentioned multicast address, and then may feed back a response message (Nsmf _ MBSSession _ CreateMBSUEContext Response) to the AMF entity as a response of Nsmf _ MBSSession _ CreateMBSUEContext Request in step 6 described above.

Then, in step 12, the AF entity may send a request (Nnef _ MBS SessionStart Request) for requesting to start a multicast service session, which may include the GPSI of the user equipment, the TMGI corresponding to the multicast service, the aggregate maximum rate (e.g. AMBR) corresponding to the multicast service, the information of at least one data flow corresponding to the multicast service, the quality of service requirement of the at least one data flow, the ID of the multicast service session, the expected duration of the multicast service session, and the data transmission time of the multicast service, to the NEF entity via the Nnef interface. The request includes the GPSI of the user equipment to indicate that this step is an operation for the UE (i.e. one specific UE). In addition, the request includes the service quality requirement of at least one data flow corresponding to the multicast service, so that the PCC technology is applied to the transmission of the multicast service data, and the combination of the PCC and the transmission of the multicast service data is realized.

Then, in step 13, the NEF entity may send a request (Npcf _ MBS SessionStart Request) for requesting a start of a multicast service session to the corresponding PCF entity through the Npcf interface and according to the SMF ID, the request may include the SUPI of the user device, the TMGI corresponding to the multicast service, one SMF ID, an aggregate maximum rate (e.g. AMBR) corresponding to the multicast service, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, an ID of the multicast service session, an expected duration of the multicast service session, and a data transmission time of the multicast service. The request includes the SUPI of the user equipment to indicate that this step is an operation for the UE (i.e., a particular UE).

Then, in step 14, the PCF entity may send a request (Nsmf _ MBS SessionStart Request) for requesting a start of a multicast service session, which may include the SUPI of the user device, the TMGI corresponding to the multicast service, the aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, the quality of service rule of the at least one data flow, the ID of the multicast service session, the expected duration of the multicast service session, and the data transmission time of the multicast service, to the respective SMF entity over the Nsmf interface and according to the SMF ID. The request includes the SUPI of the user equipment to indicate that this step is an operation for the UE (i.e., a particular UE).

Then, in step 15, the SMF entity may determine a corresponding MBS UE Context according to the TMGI, and obtain, according to the determined MBS UE Context, the S-nsai, DNN and the multicast address included in the MBS UE Context. If not previously assigned to a UPF entity, the SMF entity may select a UPF entity from a plurality of UPF entities based on the acquired S-NSSAI, DNN, and multicast address. The SMF entity may then send a request for requesting MBS session establishment to the selected UPF entity over the N4 interface (N4 MBS Session Establishment Request). The request may include a multicast address of the multicast service, a quality of service enforcement rule for at least one data flow corresponding to the multicast service, and an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service. The UPF entity may then establish a GTP user plane tunneling tree from the UPF entity to the RAN according to the multicast routing protocol in accordance with the received request to transport data (e.g., traffic data corresponding to the multicast/broadcast traffic) to be sent by the UPF entity to the RAN in a tree-like GTP user plane tunnel. The UPF entity may then assign a tunnel multicast address for transmitting traffic data corresponding to the multicast/broadcast traffic. Specifically, the UPF entity may allocate a multicast address of the GTP user plane tunnel through the N3 interface for the multicast/broadcast service, and take the multicast address of the allocated GTP user plane tunnel as a tunnel multicast address (for example, a CN N3 tunnel multicast address). The UPF entity may then assign a sixth identification (e.g., CN N3C-TEID) for the multicast/broadcast service. The SMF entity may record the ID of the PCF entity, the ID of the UPF entity, the CN N3 tunnel multicast address corresponding to the multicast service, and the CN N3C-TEID in each MBS UE Context that has activated the multicast service. In addition, if the UPF entity and the CN N3 tunnel multicast address and CN N3C-TEID corresponding to the multicast service have been allocated before, the CN N3 tunnel multicast address and CN N3C-TEID corresponding to the multicast service may be recorded in the MBS UE Context of the UE described above, and this step need not be performed.

Then, in step 16, the SMF entity may send the first information (Namf _communication_n1n MESSAGETRANSFER) to the AMF entity through the Namf interface. The first information may include a response (Activate MBS UE Context Response) to activate the MBS UE Context, which may include a TMGI corresponding to the multicast service, and the SMF entity may encapsulate the "response to activate the MBS UE Context" using the N1 MBS SM Context. In addition, the first information may further include a TMGI corresponding to the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a CN N3 tunnel multicast address corresponding to the multicast service, and a CN N3C-TEID. The SMF entity may encapsulate the TMGI corresponding to the multicast service, the qos flow identifier and the qos profile corresponding to each data flow of the multicast service, the CN N3 tunnel multicast address corresponding to the multicast service, and the CN N3C-TEID using the N2 MBS SM Container.

The AMF entity may then send a request (N2 MBS Session Start Request) to the RAN over the N2 interface requesting the start of the multicast service session in step 17. The request may include a downlink NAS Transport (DL NAS Transport) message, one cell of which is the response (Activate MBS UE Context Response) to activate MBS UE Context described above, encapsulated using N1 MBS SM Context. Through the downlink NAS Transport message, the AMF entity may instruct the RAN to send the DL NAS Transport message directly to the UE. In addition, the request may further include a TMGI corresponding to the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a multicast address for the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a CN N3 tunnel multicast address corresponding to the multicast service, and a CN N3C-TEID.

The RAN may then send the DL NAS Transport message described above to the UE through RRC signaling in step 18.

Then, in step 19, the RAN may send a response (N2 MBS Session Start Response) to the request in step 17 to the AMF entity over the N2 interface. The response may be an acknowledgement of N2 MBS Session Start Request sent to the RAN by the AMF entity as described in step 17.

The RAN may then allocate resources for transmitting multicast traffic data to its served UEs to support data flows with different quality of service requirements in step 20.

The RAN may then join the transport group corresponding to the CN N3 tunnel multicast address described above in step 21 to receive multicast traffic data from the UPF entity.

Steps 20 and 21 may not be performed if the RAN has allocated resources for said multicast service.

Then, in step 22, the AMF entity may send notification information (Namf _communication_n2 MBSMessageNotify) to the SMF entity through the Namf interface. The notification information may be an acknowledgement of the information sent by the SMF entity to the AMF entity described in step 16 above.

Then, in step 23, the SMF entity may send a response message (Nsmf _ MBS SessionStart Response) to the PCF entity via the Nsmf interface in response to the request sent by the PCF entity to the SMF entity described in step 14.

Then, in step 24, the PCF entity may send a response message (Npcf _ MBS SessionStart Response) to the NEF entity over the Npcf interface in response to the request sent by the NEF entity to the PCF entity described in step 13.

Then, in step 25, the NEF entity may send a response message (Nnef _ MBS SessionStart Response) to the AF entity through the Nnef interface in response to the request sent by the AF entity to the NEF entity described in step 12 above.

Then, in step 26, the multicast service may begin. The AF entity may send a multicast packet with a destination IP address being the multicast address of the multicast service to a downstream UPF entity. The UPF entity may then send the multicast data packet to the RAN by the transport layer multicast method described above. The RAN may then send the multicast data packet to the UE via the resources allocated to the UE.

Next, a specific flow of activating a multicast service and establishing a user plane corresponding to the multicast service based on a second activation manner in a wireless communication system will be described with reference to fig. 7.

As shown in fig. 7, in step 1, the UE may perform steps 1 to 3 in fig. 6.

Then, in step 2, the UE decides to activate the multicast service in a second activation manner, i.e. a manner compatible with conventional activation of multicast services.

Then, in step 3, the UE may send a PDU session establishment request (PDU Session Establishment Request) to the network according to S-NSSI and DNN obtained through step 1, and the PDU session establishment request may include S-NSSAI and DNN corresponding to the multicast service. The AMF entity may then select one SMF entity from the plurality of SMF entities based on S-NSSAI and DNN corresponding to the multicast service. The selected SMF entity may then select a UPF entity from a plurality of UPF entities and assign an IP address to the UE.

Then, in step 4, the UE may send an IGMP Join packet to the network with the assigned IP address after completing the PDU session establishment. When IGMP version 1 or 2 is employed, the destination IP address of the IGMP Join packet may be the multicast address of the multicast service. When IGMP version 3 is employed, the IGMP protocol portion of the IGMP Join packet may include the multicast address of the multicast service.

Then, in step 5, the UPF entity may report the multicast address corresponding to the IGMP Join packet to the SMF entity through an N4 session report message after detecting the IGMP Join packet according to the PDR configuration of the SMF entity.

Then, in step 6, the SMF entity decides to instruct the UE to activate the multicast service and sends a message to the AMF entity through Namf interface (Namf _communication_n1 MESSAGETRANSFER). The message may include information (Request MBS UE Context Activation) for requesting MBS UE Context activation to instruct the UE to activate the multicast service. The information for requesting the MBS UE Context activation may include S-nsai, DNN corresponding to a multicast service to be activated by the UE and a multicast address of the multicast service. The information for requesting MBS UE Context activation may be encapsulated using N1 MBS SM Context. Furthermore, here, the S-nsai, DNN may be determined through the above step 3, and the multicast address of the multicast service may be determined through the above step 5. Since the user plane corresponding to the multicast service is not established in the process of activating the multicast service, the other response information does not include the N2 MBS session container for the RAN by the SMF entity.

Then, in step 7, the AMF entity may send a downlink NAS Transport message (N2 downlink NAS Transport) related to the N2 interface, which may include a downlink NAS Transport (DL NAS Transport) message, which may include "Request MBS UE Context Activation" encapsulated using N1 MBS SM Container as described above, to the RAN over the N2 interface. Through the downlink NAS Transport message related to the N2 interface, the AMF entity may instruct the RAN to directly send a DL NAS Transport message to the UE.

The RAN may then send the above described DLNAS Transport message to the UE in step 8. Accordingly, the UE may acquire one S-NSSAI, one DNN, and one multicast address from the SMF entity through the DL NAS Transport message. The UE may determine whether the acquired multicast address coincides with the multicast address that the UE wants to join in step 4, and whether the acquired S-NSSAI and DNN coincide with S-NSSAI and DNN when the UE establishes the PDU session in step 3. If the three are consistent, executing the step 9.

Then, in step 9, steps 5 to 26 in fig. 6 may be performed.

Hereinafter, a UE corresponding to the method shown in fig. 2 according to an embodiment of the present disclosure will be described with reference to fig. 8. Fig. 8 is a schematic structural diagram of a UE 800 according to an embodiment of the present disclosure. Since the function of the UE 800 is the same as the details of the method described above with reference to fig. 2, a detailed description of the same is omitted herein for simplicity. As shown in fig. 8, the UE 800 includes: a determining unit 810 configured to determine an activation manner for activating the multicast service; an activation unit 820 configured to activate the multicast service according to the determined activation manner and at least through a session management function entity, wherein a multicast service session corresponding to the multicast service is performed during the activation of the multicast service; and a receiving unit 830 configured to receive service data corresponding to the multicast service. In addition to these three units, the UE 800 may include other components, however, since these components are not related to the contents of the embodiments of the present disclosure, illustration and description thereof are omitted herein.

In the present disclosure, the activation manner determined by the determination unit 810 may be the first activation manner or the second activation manner.

In the present disclosure, the determining unit 810 may determine an activation manner for activating the multicast service according to its own attribute. The attributes described herein may refer to the support capabilities of the UE for various applications. For example, when the UE supports only a mobile application or the UE does not need an IP data transmission function, the UE may determine that an activation manner for activating a multicast service is a first activation manner. For example, when the UE needs to support an IP-based application, the UE may determine that the activation manner for activating the multicast service is a second activation manner.

It is to be appreciated that the determining unit 810 may also determine the activation manner for activating the multicast service according to other manners, which are not limited in this disclosure.

Further, according to an example of the present disclosure, the determining unit 810 may determine a first identity and a second identity corresponding to the multicast service, wherein the first identity and the second identity are used for an access and mobility management function entity to select the session management function entity. In particular, the first identification may be used to identify a network fragment corresponding to the multicast service. For example, the first identification may be single network segment selection assistance information (Single Network Slice Selection Assistance Information, S-NSSAI). Further, the second identification may be used to identify a data network corresponding to the multicast service. For example, the second identification may be a data network name (Data Network Name, DNN).

In this example, the determining unit 810 may determine the first and second identifications corresponding to the multicast traffic in the following manner.

In particular, receiving unit 830 may obtain, from a Policy Control Function (PCF) entity, user device routing policy (UE Route Selection Policy Rule, URSP) rules corresponding to each of the at least one multicast service, wherein each user device routing policy rule includes at least a multicast address of the respective multicast service. For example, first, the UE may initiate a registration procedure with the network; then, in the process that the AMF entity and the PCF entity establish the UE policy association (UE Policy Association), the PCF entity may provide URSP rules corresponding to each of the at least one multicast service to the UE through the AMF entity, and accordingly, the UE may obtain URSP rules corresponding to each of the at least one multicast service from the PCF entity through the AMF entity.

The determining unit 810 may then determine a user device routing policy rule corresponding to the multicast service according to the multicast address of the multicast service. For example, when the UE wants to activate a multicast service, the determining unit 810 may determine URSP rules corresponding to the multicast service according to a multicast address of the multicast service.

The determining unit 810 may then determine the first and second identities corresponding to the multicast traffic according to the determined user device routing policy rule. For example, the UE may obtain a routing descriptor (Route Selection Descriptor) according to URSP rules corresponding to the multicast service, wherein the routing descriptor includes a first identity and a second identity; then, the UE uses the first identifier and the second identifier included in the routing descriptor as the first identifier and the second identifier corresponding to the multicast service.

In the present disclosure, the activation unit 820 activates the multicast service according to the determined activation manner and at least through a session management function entity, wherein a multicast service session corresponding to the multicast service is performed during activation of the multicast service. That is, a user plane corresponding to a multicast service is established during activation of the multicast service.

According to one example of the present disclosure, when the activation manner determined by the determining unit 810 is the first activation manner, the activating unit 820 activates the multicast service according to the first activation manner and at least through the session management function entity. In this example, the UE800 may further include a transmitting unit 840.

In particular, activation unit 820 can determine a third identification identifying a user device multicast service context established for activating the multicast service. For example, the UE may assign an Identification (ID) to the user equipment multicast service context. The "user equipment multicast service Context established for activating the multicast service" described herein may also be referred to as a user equipment multicast service Context (MBS UE Context) for the multicast service. Accordingly, the third identification may also be referred to as an identification (MBS UE Context ID) of the user device multicast service context for the multicast service.

Then, the transmitting unit 840 transmits a request for activating the user device multicast service context to the session management function entity, the request for activating the user device multicast service context including the third identification and the multicast address of the multicast service. For example, the sending unit 840 may send a request for activating the user equipment multicast service context to the session management function entity via the access and mobility management function entity.

Specifically, first, the sending unit 840 may send an uplink Non-Access Stratum (NAS) Transport (UL NAS Transport) message to the AMF entity, where the UL NAS Transport message includes at least three cells, a first cell is a first identifier corresponding to the multicast service, a second cell is a second identifier corresponding to the multicast service, and a third cell is a request for activating an MBS UE Context. The request for activating the MBS UE Context may be denoted Active MBS UE Context Request and may include a third identification corresponding to the multicast service and a multicast address of the multicast service. In an example where the first identity is S-NSSAI, the second identity is DNN, and the third identity is MBS UE Context ID, the UL NAS Transport message sent by the UE to the AMF entity may include three cells, where the first cell is S-NSSAI corresponding to the multicast service, the second cell is DNN corresponding to the multicast service, and the third cell is a request for activating MBS UE Context, where the request for activating MBS UE Context includes MBS UE Context ID corresponding to the multicast service and a multicast address of the multicast service.

In the present disclosure, the transmitting unit 840 may encapsulate the "request for activating MBS UE Context" described herein using a specific format. For example, the specific format may be a session management Container (N1 MBS SM Container) of the multicast service related to the N1 interface.

The AMF entity may then send a request to the corresponding SMF entity via the Nsmf interface, which may be used to request creation of MBS UE Context related to the MBS session. The request may be denoted Nsmf _ MBSSession _ CreateMBSUEContext Request. The request may include a first identification corresponding to the multicast service, a second identification, and the above-described "request for activation MBSUE Context". In the example where the first identification is S-NSSAI, the second identification is DNN, and the third identification is MBS UE Context ID, the AMF entity may send a request to the SMF entity over the Nsmf interface, which may include S-NSSAI corresponding to the multicast service, DNN corresponding to the multicast service, and "request for activating MBS UE Context" described above.

The SMF entity may then record the received RANID in the MBS UE Context of the UE, so that the SMF entity obtains the identities of the serving base stations of all user equipments that activate the multicast service through the SMF entity. Furthermore, the SMF entity will determine a fourth identity corresponding to the multicast service from the received information, wherein the fourth identity is used by the user equipment to determine whether the multicast service is activated and the fourth identity is an identity assigned to the multicast service by an Application Function (AF) entity, and the SMF entity will feed back the fourth identity to the UE. These operations are described in detail below in connection with the methods performed by the SMF entity described in connection with fig. 9-10.

Then, the receiving unit 830 receives a response to the request for activating the user device multicast service context from the session management function entity, the response including a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated. In particular, the UE may receive a response to the request for activating the user equipment multicast service context from the session management function entity via a serving base station of the user equipment and the access and mobility management function entity.

In particular, first, a session management function may send first information to the access and mobility management function, wherein the first information comprises a response to the request for activating the user device multicast service context and information related to the multicast service session. Further, the "information related to the multicast service session" described herein may include at least the fourth identification, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a tunnel multicast address corresponding to the multicast service, and a sixth identification. The "tunnel multicast address" described herein may be a tunnel multicast address (Transport IP Multicast Address) and may be referred to as a CN N3 tunnel multicast address. The "sixth identity" described herein may be a Common tunnel endpoint identity (Common-Tunnel End point ID, C-TEID) and may be referred to as CN N3C-TEID. In particular, the methods performed by the SMF entity described below in connection with fig. 4-5 will be described in detail.

Accordingly, the receiving unit 830 can obtain a response to the request for activating the user device multicast service context from the session management function entity.

A specific example of the receiving unit 830 obtaining a response to a request for activating the user device multicast service context from the session management function entity is given below.

The RAN may then send the DL NAS Transport message described above to the UE. Accordingly, the receiving unit 830 may acquire the fourth identifier corresponding to the multicast service through the DL NAS Transport message. In an example where the fourth identity is a TMGI, the UE may acquire the TMGI corresponding to the multicast service through a DL NAS Transport message.

According to one example of the present disclosure, when the activation manner determined by the determining unit 810 is the second activation manner, the activating unit 820 activates the multicast service according to the second activation manner and at least through the session management function entity. In this example, the UE 800 may further include a transmitting unit 840.

Specifically, the activation unit 820 may acquire an internet protocol address (IP address) from the session management function entity according to the first identifier and the second identifier corresponding to the multicast service. For example, the UE may select the session management function according to the first identifier and the second identifier and establish a protocol data unit session, and obtain an internet protocol address from the session management function. In an example where the first identity is S-NSSAI and the second identity is DNN, the UE may send a PDU session establishment request to the network according to S-NSSAI and DNN corresponding to the multicast service, which may include S-NSSAI and DNN corresponding to the multicast service. The AMF entity may then select one SMF entity from the plurality of SMF entities based on S-NSSAI and DNN corresponding to the multicast service. The selected SMF entity may then select a UPF entity from a plurality of UPF entities and assign an IP address to the UE.

The transmitting unit 840 may then transmit the data packet to the network according to the acquired internet protocol address so that a User Plane Function (UPF) entity in the network acquires the data packet. For example, the UE may send a data packet to the network according to the acquired internet protocol address so that a user plane function entity in the network participating in the establishment of the protocol data unit session acquires the data packet. In addition, the data packet is used to indicate a multicast service that the user device wants to activate. The destination address of the data packet is or the protocol part of the data packet comprises the multicast address of the multicast service. For example, after step S3021", the UE may send an IGMP Join packet to the network with the assigned IP address after completing the PDU session establishment. When IGMP version 1 or 2 is employed, the destination IP address of the IGMP Join packet may be the multicast address of the multicast service. When IGMP version 3 is employed, the IGMP protocol portion of the IGMP Join packet may include the multicast address of the multicast service.

The activation unit 820 may then obtain a first identity, a second identity and a multicast address from the session management function entity.

In particular, the SMF entity may obtain, from the above-mentioned user plane function entity, a multicast address of a multicast service to be activated by the user equipment. For example, the UPF entity may be configured according to a packet detection rule (Packet Dection Rule, PDR) of the SMF entity, and report a multicast address corresponding to the IGMP Join packet to the SMF entity after detecting the IGMP Join packet (e.g., report the multicast address corresponding to the IGMP Join packet through an N4 session report message).

The AMF entity may then send a downlink NAS transport message associated with the N2 interface to the RAN over the N2 interface. The downlink NAS transport message related to the N2 interface may be denoted as N2 downlink NAS Transport. The downlink NAS Transport message related to the N2 interface may include a downlink NAS Transport (DL NAS Transport) message, which may include "Request MBS UE Context Activation" encapsulated using the N1 MBS SM Container described above. Through the downlink NAS Transport message related to the N2 interface, the AMF entity may instruct the RAN to directly send DL NAS Transport message to the UE.

Thereafter, the activation unit 820 may determine whether the acquired first identifier is identical to the determined first identifier, whether the acquired second identifier is identical to the determined second identifier, and whether the acquired multicast address is identical to the multicast address of the multicast service. For example, the activation unit 820 may determine whether the multicast address in "Request MBS UE Context Activation" encapsulated using the N1 MBS SM Container is identical to the multicast address of the multicast service that the UE wants to activate, and whether the S-nsai, DNN in "Request MBS UE Context Activation" encapsulated using the N1 MBS SM Container is identical to the S-nsai, DNN at the time of establishing the PDU session, according to the DL NAS Transport message received from the RAN.

When the activation unit 820 determines that the acquired first identity is different from the determined first identity and/or the acquired second identity is different from the determined second identity and/or the acquired multicast address is different from the multicast address of the multicast service, the UE cannot activate the multicast service. In contrast, when the activation unit 820 determines that the acquired first identifier is the same as the determined first identifier, the acquired second identifier is the same as the determined second identifier, and the acquired multicast address is the same as the multicast address of the multicast service, the activation unit 820 may activate the multicast service.

In particular, the determining unit 810 may determine a third identification for identifying a user device multicast service context established for activating the multicast service. The sending unit 840 may then send a request for activating the user device multicast service context to the session management function entity, the request for activating the user device multicast service context including the third identification and the multicast address of the multicast service. The receiving unit 830 may then receive a response from the session management function entity to the request for activating the user device multicast service context, the response including a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated.

Then, the receiving unit 830 receives service data corresponding to the multicast service. For example, when the user device activates the multicast service and a multicast service session corresponding to the multicast service is successfully started, the AF entity may transmit multicast service data (e.g., multicast service data packets) having a destination IP address that is a multicast address of the multicast service to the downstream UPF entity. The UPF entity then sends the multicast traffic data to the RAN. The RAN may then send multicast traffic data to the UE via the resources allocated to the UE.

According to the user device of the embodiment of the disclosure, the user device can determine the activation mode for activating the multicast service, and activate the multicast service according to the determined activation mode and at least through a session management functional entity in the network, thereby optimizing or being compatible with the conventional process of activating the multicast service. In addition, in the process of activating the multicast service, a multicast service session corresponding to the multicast service is started, so that a user plane corresponding to the multicast service is established in the process of activating the multicast service.

Hereinafter, an SMF entity corresponding to the method shown in fig. 4 according to an embodiment of the present disclosure will be described with reference to fig. 9. Fig. 9 is a schematic diagram of a structure of an SMF entity 900 according to an embodiment of the present disclosure. Since the function of the SMF entity 900 is the same as the details of the method described above with reference to fig. 4, a detailed description of the same is omitted herein for simplicity. As shown in fig. 9, the SMF entity 900 includes: a receiving unit 910 configured to receive, from a user device, a request for activating a user device multicast service context, the user device multicast service context being established for activating a multicast service, the request for activating the user device multicast service context including the third identification and a multicast address of the multicast service, the third identification identifying the user device multicast service context; a determining unit 920 configured to determine a response to the request for activating a user device multicast service context, wherein the response comprises a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated; an obtaining unit 930 configured to obtain a fifth identifier corresponding to the multicast service, where the fifth identifier is used to identify a start of a multicast service session corresponding to the multicast service; a control unit 940 configured to conduct the multicast service session; and a transmitting unit 950 configured to transmit the response to the user device. In addition to these five elements, the SMF entity 900 may include other components, however, since these components are not related to the contents of the embodiments of the present disclosure, illustration and description thereof are omitted herein.

As shown in fig. 9, the receiving unit 910 receives, from a user device, a request for activating a user device multicast service context, the user device multicast service context being established for activating the multicast service, the request for activating the user device multicast service context including the third identification and a multicast address of the multicast service, the third identification identifying the user device multicast service context.

Further, according to an example of the present disclosure, the receiving unit 910 may record the identification of the serving base station of the user equipment in the user equipment multicast service context so that the SMF entity acquires the identifications of the serving base stations of all user equipment activating the multicast service through the SMF entity to be used when setting up the user plane of the MBS session. For example, the receiving unit 910 may record the received RAN ID in MBS UE Context of the UE.

Returning to fig. 9, the determining unit 920 determines a response to the request for activating the user device multicast service context, wherein the response includes a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated. For example, the determining unit 920 determines a fourth identifier corresponding to the multicast service according to at least the first identifier, the second identifier, and the multicast address of the multicast service, where the fourth identifier is an identifier allocated by an application functional entity to the multicast service.

Specifically, the determining unit 920 may determine whether the user device can use the multicast service. For example, the SMF entity may obtain subscription data of the UE from a Unified data management (Unified DATA MANAGEMENT, UDM) entity to determine whether the UE has subscribed to the multicast service. If the UE signs up for the multicast service, the SMF entity may determine that the UE is able to use the multicast service. If the UE is not subscribed to the multicast service, the SMF entity may determine that the UE cannot use the multicast service.

When the determining unit 920 determines that the UE can use the multicast service, the transmitting unit 950 transmits a notification to the application function entity, wherein the notification is a notification of the multicast service authorization request. The notification comprises at least the first identification, the second identification, a multicast address of the multicast service, and an identification of the session management function entity. The "identification of the session management function entity" is herein used to facilitate the application function entity to acquire the session management function entity involved in activating the multicast service by all user apparatuses to activate the multicast service, so as to be used when a user plane corresponding to the multicast service is subsequently established.

Specifically, the sending unit 950 may send the notification directly to the application function entity. For example, the SMF entity may determine the corresponding AF entity according to the first identifier, the second identifier, and the multicast address of the multicast service. The SMF entity may then send a notification to the determined AF entity. The notification may include the first identification, the second identification, the private and public identifications of the user device, the multicast address of the multicast service, and the identification of the session management function entity (e.g., the SMF ID of the SMF entity).

Alternatively, the sending unit 950 may send the notification to the application function entity via the network opening function entity.

In an example in which the transmitting unit 950 transmits a notification to the application function entity via the network opening function entity, first, the transmitting unit 950 may transmit a notification to the network opening function entity, which may include the first identification, the second identification, a private identification and a public identification of the user device (e.g., common public subscription identifier (Generic Public Subscription Identifier, GPSI)), a multicast address of the multicast service, an identification of the session management function entity, and an identification of the application function entity (e.g., an AF ID of an AF entity determined by the SMF entity), so that the network opening function entity transmits another notification to the application function entity according to the identification of the application function entity. The further notification may comprise a first identification, said second identification, a private and public identification of said user device, a multicast address of said multicast service, and an identification of said session management function node entity.

The AF entity may then record the received SMF ID for use in setting up the user plane of the MBS session. In addition, the AF entity may also determine a fourth identification corresponding to the multicast service. The fourth identification described herein may be a temporary mobile group identification (Tempory Mobile Group Identify, TMGI) assigned by the AF entity to the multicast service activated based on the multicast address.

Accordingly, the receiving unit 910 may receive a response to the notification from the application function entity, where the response to the notification includes a fourth identifier corresponding to the multicast service, thereby acquiring the fourth identifier corresponding to the multicast service from the application function entity. In the example where the fourth identifier is a TMGI, the receiving unit 910 may directly obtain the TMGI corresponding to the multicast service from the AF entity, or the receiving unit 910 may obtain the TMGI corresponding to the multicast service from the AF entity via the NEF entity.

Returning to fig. 9, the acquiring unit 930 acquires a fifth identifier corresponding to the multicast service, where the fifth identifier is used to identify the start of the multicast service session corresponding to the multicast service. The fifth identification may be a multicast service session start identifier (Session Start Indicator) to start the multicast service session to establish a user plane corresponding to the multicast service. The acquisition unit 930 may be operated simultaneously with the above-described determination unit 920, or may be operated after the acquisition unit 930 is operated.

In an example in which the acquisition unit 930 operates simultaneously with the above-described determination unit 920, when the receiving unit 910 receives a response to the request for activating the user device multicast service context from the application functional entity, the receiving unit 910 may further receive a fifth identification corresponding to the multicast service from the application functional entity. For example, the receiving unit 910 may receive a response message from the application function entity, and the response message includes both a response to the request for activating the user device multicast service context and a fifth identification corresponding to the multicast service.

According to one example of the present disclosure, the receiving unit 910 may receive a response to the request for activating the user device multicast service context and a fifth identification corresponding to the multicast service directly from the application function entity. For example, when the AF entity receives a message from the SMF entity, the fourth identification, which is a response to the request for activating the user device multicast service context, may be a TMGI. Accordingly, the AF entity may feed back response information of notification of the MBS authorization request to the SMF entity through the Nsmf interface, which may be denoted as Nsmf _ MBS AuthorizationRequest Notify Response, and which may include a TMGI corresponding to the multicast service and a multicast service session start identifier.

According to another example of the present disclosure, the receiving unit 910 may receive, from the application function entity, a response to the request for activating the user device multicast service context and a fifth identification corresponding to the multicast service via the network opening function entity. For example, when the AF entity receives a message from the NEF entity, the fourth identification, which is a response to the request for activating the user device multicast service context, may be a TMGI. Accordingly, the AF entity may feed back response information of the notification of the MBS authorization request to the NEF entity through the Nnef interface, which may be denoted as Nnef MBS AuthorizationRequest Notify Response, and which may include the TMGI corresponding to the multicast service and the multicast service session start identifier. Then, the NEF entity may feedback response information, which may be denoted as Nsmf _ MBS AuthorizationRequest Notify Response, of the notification of the MBS authorization request to the SMF entity through the Nsmf interface, and the response information may include the TMGI corresponding to the multicast service and the multicast service session start identifier.

Thereafter, the SMF entity may create the MBS UE Context based on the above-described multicast address for the UE, and then may feedback a response message to the AMF entity, which may be the response of Nsmf _ MBSSession _ CreateMBSUEContext Request described above. The response information may be an acknowledgement to Nsmf _ MBSSession _ CreateMBSUEContext Request described above, which may be denoted Nsmf _ MBSSession _ CreateMBSUEContext Response.

Then, the control unit 940 performs the multicast service session, and the transmitting unit 950 transmits a response to the request for activating the user device multicast service context to the user device.

First, the receiving unit 910 receives a first request from a policy control function entity, wherein the first request is for requesting the start of a multicast service Session (MBS Session). The first request may include at least a first identification of the user device, a fourth identification corresponding to a multicast service, a quality of service rule for at least one data flow corresponding to the multicast service, and an identification of the multicast service session. In addition, the first request may also include other information, such as an expected duration of the multicast service session (ESTIMATED SESSION DURATION), and a data transmission time of the multicast service (time to MBS DATA TRANSFER).

Further, according to one example of the present disclosure, the first request is determined by the policy control function entity based on a second request received from a network opening function entity or an application function entity, the second request being for the network opening function entity or the application function entity to request a start of a multicast traffic session from the policy control function entity. The second request may include at least a first identification of the user device, the fourth identification, an identification of the session management function entity, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, and an identification of the multicast service session. In addition, the second request may also include other information, such as the expected duration of the multicast service session, and the data transmission time of the multicast service.

Thereafter, the control unit 940 may generate a quality of service flow identifier (QoS Flow Identity, QFI), a quality of service Profile (QoS Profile), and a quality of service execution Rule (QER) corresponding to each of at least one data flow corresponding to the multicast service according to the quality of service Rule of each data flow. In the present disclosure, the quality of service flow identity corresponding to each data flow may also be referred to as a quality of service flow identity (MBS QFI) of the multicast service. Further, the quality of service enforcement rules described herein may be similar to conventional N4 QER rules.

The control unit 940 may then select one of the user plane functional entities based on the fourth identification. In the example where the fourth identifier is a TMGI, the SMF entity may determine a corresponding MBS UE Context according to the TMGI, and obtain, according to the determined MBS UE Context, an S-nsai, a DNN, and a multicast address included in the MBS UE Context. The SMF entity may then select a UPF entity from the plurality of UPF entities based on the acquired S-NSSAI, DNN, and multicast address.

The sending unit 950 may then send a fourth request to the selected user plane functional entity, wherein the fourth request is for establishing transmission resources of the multicast service session. The fourth request includes at least a multicast address of the multicast service, a quality of service enforcement rule for at least one data flow corresponding to the multicast service, and an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service. For example, the SMF entity may send a request for requesting MBS session establishment to the selected UPF entity through the N4 interface, which may be denoted as N4 MBS Session Establishment Request.

The receiving unit 910 may then obtain, from the selected user plane functional entity, a response to the fourth request, where the response to the fourth request includes a tunnel multicast address allocated by the selected user plane functional entity for transmitting traffic data corresponding to the multicast traffic, and a sixth identification corresponding to the tunnel multicast address, where the tunnel multicast address is used for multicast tunneling between network entities (e.g., multicast tunneling between the UPF entity and the RAN), and the sixth identification is used for identifying a transport tunnel (e.g., a GTP-related transport tunnel) for the multicast traffic.

Accordingly, the receiving unit 910 may obtain a tunnel multicast address corresponding to the multicast service from the selected UPF entity, and obtain a sixth identification corresponding to the multicast service from the selected user plane function entity. The SMF entity may then record the tunnel multicast address and the sixth identification in respective user device multicast service contexts in which the multicast service has been activated.

The transmitting unit 950 may then transmit first information to the access and mobility management function entity, wherein the first information includes the response and information related to the multicast service session, such that the access and mobility management function entity transmits a fifth request to a corresponding serving base station according to the information related to the multicast service session, and transmits the response to the user equipment via the corresponding serving base station, wherein the fifth request is for requesting a start of the multicast service session. The "information related to the multicast service session" described herein includes at least the fourth identifier, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a quality of service flow identifier and a quality of service profile corresponding to each data flow, the tunnel multicast address, and the sixth identifier.

Through the above operation, not only the user plane corresponding to the multicast service is established, but also the UE activates the multicast service.

The serving base station of the UE may then send a response to the fifth request to the access and mobility management function entity. For example, the RAN may send a response to the fifth request to the AMF entity over the N2 interface in response to the fifth request for requesting MBS session initiation sent by the AMF entity to the RAN as described above. The response may be an acknowledgement of N2 MBS Session Start Request, described above, sent by the AMF entity to the RAN, and may be denoted as N2 MBS Session Start Response.

The AMF entity may then send a notification message to the SMF entity to notify the first information sent to the AMF entity by the sending unit 950 as described above. For example, the AMF entity may send the notification information to the SMF entity over the Namf interface. The notification information may be an acknowledgement of the first information sent by the sending unit 950 to the AMF entity. The notification information may be MBS message transmission related to the N2 interface, which may be denoted as Namf _communication_n2MBSMessageNotify, communicated over the Namf interface. Accordingly, the receiving unit 910 receives notification information for the first information from the AMF entity.

The sending unit 950 may then send a response message to the PCF entity via the Nsmf interface in response to the first request sent by the PCF entity to the SMF entity. For example, the response information may be an acknowledgement of "Nsmf _ MBS SessionStart Request" described in step S4041 as being sent by the PCF entity to the SMF entity, and may be denoted as Nsmf _ MBSSessionStart Response.

Further, the PCF entity may then send a response message to the NEF entity via the Npcf interface in response to the second request sent by the NEF entity to the PCF entity as described in step S4041. For example, the response information may be an acknowledgement of "Npcf _ MBS SessionStart Request" described in step S4041 as being sent by the NEF entity to the PCF entity, and may be denoted as Npcf _ MBS SessionStart Response.

According to the session management functional entity of the embodiment of the present disclosure, during the process of activating the multicast service, the session management functional entity may receive the third identifier corresponding to the multicast service to be activated by the user device and the multicast address of the multicast service, and determine the fourth identifier corresponding to the multicast service and the fifth identifier according to at least these information, so as to enable the multicast service session corresponding to the multicast service to be performed according to the fifth identifier to establish the user plane corresponding to the multicast service, and feed back the fourth identifier to the user device so that the user device activates the multicast service, thereby implementing the establishment of the user plane corresponding to the multicast service during the activation of the multicast service.

Hereinafter, an SMF entity corresponding to the method shown in fig. 5 according to an embodiment of the present disclosure will be described with reference to fig. 10. Fig. 10 is a schematic structural diagram of an SMF entity 1000 according to an embodiment of the present disclosure. Since the function of the SMF entity 1000 is the same as the details of the method described above with reference to fig. 5, a detailed description of the same is omitted herein for simplicity. As shown in fig. 10, the SMF entity 1000 includes: an allocation unit 1010 configured to establish a protocol data unit session and to allocate an internet protocol address to the user device; an obtaining unit 1020 configured to obtain, from a user plane function entity participating in the establishment of the protocol data unit session, a multicast address of a multicast service to be activated by the user equipment, wherein the multicast address is obtained after the user equipment sends a data packet to a network including the user plane function entity according to the internet protocol address, wherein the data packet is used to indicate the multicast service the user equipment wants to activate; a transmitting unit 1030 configured to transmit, to the user device, a request for instructing the user device to activate the multicast service, wherein the request for instructing the user device to activate the multicast service includes a first identifier, a second identifier, and a multicast address of the multicast service corresponding to the multicast service to be activated by the user device; a receiving unit 1040 configured to receive, from a user device, a request for activating a user device multicast service context, the user device multicast service context being established for activating a multicast service, the request for activating the user device multicast service context including the third identification and a multicast address of the multicast service, the third identification identifying the user device multicast service context; a determining unit 1050 configured to determine a response to the request for activating a user device multicast service context, wherein the response comprises a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated; an obtaining unit 1020 further configured to obtain a fifth identifier corresponding to the multicast service, where the fifth identifier is used to identify a start of a multicast service session corresponding to the multicast service; a control unit 1060 configured to conduct the multicast service session; and a transmitting unit 1030 configured to transmit the response to the user device. In addition to these six elements, the SMF entity 1000 may include other components, however, since these components are not related to the contents of the embodiments of the present disclosure, illustration and description thereof are omitted herein.

As shown in fig. 10, the allocation unit 1010 may establish a protocol data unit session and allocate an internet protocol address (IP address) to the user device. For example, in an example where the first identity is S-NSSAI and the second identity is DNN, the UE may send a PDU session establishment request to the network according to S-NSSAI and DNN corresponding to the multicast service, which may include S-NSSAI and DNN corresponding to the multicast service. The AMF entity may then select one SMF entity from the plurality of SMF entities based on S-NSSAI and DNN corresponding to the multicast service. The selected SMF entity may then select a UPF entity from a plurality of UPF entities and assign an IP address to the UE.

The obtaining unit 1020 may obtain, from a user plane function entity participating in the establishment of the protocol data unit session, a multicast address of a multicast service to be activated by the user equipment, wherein the multicast address is obtained after the user equipment sends a data packet to a network including the user plane function entity according to the internet protocol address, wherein the data packet is used to indicate the multicast service to be activated by the user equipment, and a destination address of the data packet is the multicast address of the multicast service, or a protocol portion of the data packet includes the multicast address of the multicast service.

Accordingly, the acquiring unit 1020 may acquire the multicast address of the multicast service to be activated by the user equipment from the above-mentioned user plane function entity. For example, the UPF entity may be configured according to a packet detection rule (Packet Dection Rule, PDR) of the SMF entity, and report a multicast address corresponding to the IGMP Join packet to the SMF entity after detecting the IGMP Join packet (e.g., report the multicast address corresponding to the IGMP Join packet through an N4 session report message).

When the SMF entity decides to instruct the user device to activate the multicast service, the transmitting unit 1030 may transmit a request for instructing the user device to activate the multicast service to the user device, wherein the request for instructing the user device to activate the multicast service includes a first identification, a second identification, and a multicast address of the multicast service corresponding to the multicast service to be activated by the user device. For example, the SMF entity may send a request to the user device via an access and mobility management function for instructing the user device to activate the multicast service.

For example, the sending unit 1030 may send a message to the AMF entity via the Namf interface, which may be denoted as Namf _communication_n1MESSAGETRANSFER, for example, via a Namf interface Communication, N1 interface related message transmission. The message may include a request for instructing the user device to activate the multicast service. For example, the request for instructing the user equipment to activate the multicast service may be information for requesting MBS UE Context activation to instruct the UE to activate the multicast service. The information for requesting MBS UE Context activation may include S-nsai, DNN corresponding to a multicast service to be activated by the user equipment and a multicast address of the multicast service, and the information for requesting MBS UE Context activation may be denoted as Request MBS UE Context Activation. In addition, "Request MBS UE Context Activation" described herein may be encapsulated in the particular format described above (e.g., N1MBS SM Container).

The AMF entity may then send a downlink NAS transport message associated with the N2 interface to the RAN over the N2 interface. The downlink NAS transport message related to the N2 interface may be denoted as N2 downlink NAS Transport. The downlink NAS Transport message related to the N2 interface may include a downlink NAS Transport (DL NAS Transport) message, which may include "Request MBS UE Context Activation" encapsulated using the N1 MBS SM Container described above. Through the downlink NAS Transport message related to the N2 interface, the AMF entity may instruct the RAN to directly send a DL NAS Transport message to the UE. The RAN may then send the DL NAS Transport message described above to the UE. Accordingly, the UE may obtain a first identity, a second identity and a multicast address from the SMF entity via DL NAS Transport message.

The receiving unit 1040 may then receive a request from the user device for activating a user device multicast service context that is established by the user device for activating the multicast service, the request for activating the user device multicast service context including the third identification for identifying the user device multicast service context and a multicast address for the multicast service. The determining unit 1050 determines a response to the request for activating a user device multicast service context, wherein the response comprises a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated. The obtaining unit 1020 obtains a fifth identifier corresponding to the multicast service, where the fifth identifier is used to identify a start of a multicast service session corresponding to the multicast service. The control unit 1060 performs the multicast service session, and the transmitting unit 1030 transmits a response to the request for activating the user device multicast service context to the user device.

Operations performed by the above-described acquisition unit 1020, transmission unit 1030, reception unit 1040, determination unit 1050, and control unit 1060 are similar to those performed by the acquisition unit 930, transmission unit 950, reception unit 910, determination unit 920, and control unit 940, respectively, in fig. 9, and are not described here again.

The principles of the above-described embodiments are implemented based on the architecture of the wireless communication system shown in fig. 1. According to another implementation of the present disclosure, the principles of the above-described embodiments may also be implemented based on the architecture of other wireless communication systems. Fig. 11 illustrates a schematic diagram of an architecture of another wireless communication system in which the principles of embodiments of the present disclosure may be applied.

Specifically, the wireless communication system 1100 includes a first type application function (Application Function, AF) entity 1101, a network open function (Network Exposure Function, NEF) entity 1102, a Multicast/broadcast service function (Multicast/Broadcast Service Function, MBSF) entity 1103, a policy control function (Policy Control Function, PCF) entity 1104, a first type session management function (Session Management Function, SMF) entity 1105, a first type access and mobility management function (ACCESS AND Mobility management Function, AMF) entity 1106, a Multicast/broadcast service user plane (Multicast/Broadcast Service User plane, MBSU) entity 1107, a first type user plane function (User Plane Function, UPF) entity 1108, and a radio access network (Radio Access Network, RAN) 1109 and UEs 1110 served thereby, wherein the NEF entity 1102, MBSF entity 1103, PCF entity 1104, a first type SMF entity, a first type AMF entity 1106 belongs to an entity of a control plane, and the MBSU entity 1107 and the first type UPF entity 1108 belong to an entity of a user plane.

In the present disclosure, the first type AF entity 1101 may provide service data (e.g., MBS service data) and support the provision of service data to downstream entities in a network in a multicast/broadcast manner, and thus may be referred to as MBS AF, or MBS-AF, or MB-AF, or M-AF entity. The first type SMF entity 1105 is an SMF entity supporting a multicast/broadcast service, and thus may be referred to as an MBS SMF, or MBS-SMF, or MB-SMF, or M-SMF entity. The first type AMF entity 1106 is an AMF entity supporting a multicast/broadcast service, and thus may be referred to as an MBS AMF, or MBS-AMF, or MB-AMF, or M-AMF entity. The first type of UPF entity 1108 is a UPF entity that supports multicast/broadcast services and, thus, may be referred to as an MBS UPF, or MBS-UPF, or MB-UPF, or M-UPF entity. For convenience, these terms may sometimes be used interchangeably.

In addition, the UE 1110 may be connected to the RAN 1109 through a Uu interface. RAN 1109 may be coupled to first type AMF entity 1106 via an N2 interface and to first type UPF entity 1108 via an MB-N3 interface. The first type UPF entity 1108 may be connected to the first type SMF entity 1105 via an Nx interface and to the MBSU entity 1107 via an N6 interface. The first type AMF entity 1106 is connected to the first type SMF entity 1105 via an MB-N11 interface. The first type SMF entity 1105 is connected to PCF entity 1104 via an interface (e.g., np). PCF entity 1104 may be coupled to MBSF entity 1103 via an interface (e.g., nq). In addition, the first type SMF entity 1105 may also be directly connected to the MBSF entity 1103 through an interface n6mb_c interface. MBSF entity 1103 is connected to NEF entity 1102 via NxMB-C interface. The NEF entity 1102 is connected to the first type AF entity 1101 through an N33 interface. MBSU entity 1107 is connected to the first type AF entity 1101 through a NxMB-U interface.

The wireless communication system 1100 may further include a second type AF entity, a second type SMF entity, a second type AMF entity, and a second type UPF entity (not shown). In the case of multicast/broadcast services, the second type AF entity may have the functions of the first type AF entity 1101, the MBSF entity 1103, and the MBSU entity 1107. The second type AF entity may also support protocol data unit (Protocol Data Unit, PDU) session traffic (e.g., IP type PDU session traffic). The second type SMF entity may be an SMF entity supporting PDU session traffic (e.g., IP type PDU session traffic). The second type AMF entity may be an AMF entity supporting PDU session traffic (e.g., IP type PDU session traffic). The second type of UPF entity may be a UPF entity supporting PDU session traffic (e.g., IP type PDU session traffic). The second type of AF entity described herein may be AF entity 110 in fig. 1, the second type of SMF entity may be SMF entity 130 in fig. 1, the second type of AMF entity may be AMF entity 140 in fig. 1, and the second type of UPF entity may be UPF entity 150 in fig. 1.

Furthermore, in the present disclosure, MBSF entities are entities dedicated to the control plane of MBS services, which may be used for signaling portions to satisfy service layer capabilities in transport-only and full-service modes, and may provide interfaces to first type AF entities or content providers in transport-only mode. MBSU entities are entities dedicated to the user plane of MBS services, which can be used to process the payload portion to meet the service layer capabilities. The NEF entity may support QoS capability openness, event subscription capability openness, traffic steering of AF requests, and parameter issuance of AF requests, etc. PCF entities may support a unified policy framework to manage network behavior, provide policy rules to control the control plane, and so on. The first type of SMF entity and the second type of SMF entity are similar and may support session management, etc., where the session management may include session establishment, modification, release, etc. The first type AMF entity and the second type AMF entity are similar, and can support access authentication, mobile management, registration management, connection management, legal answering of the UE, session management information between the UE and the SMF entity, and the like. The first type of UPF entity, like the second type of UPF entity, may have routing functions for the data packets, e.g., may obtain the data packets from the network and send the data packets to the RAN, etc. The RAN may be an access network formed by base stations. The base station here may be any type of base station, such as a 5G base station, a Next Generation (NG) RAN, or a base station in a conventional communication system or a wifi ap, etc.

As shown in fig. 12, in step 1, the UE may initiate a procedure of activating a multicast service through a first activation manner. Alternatively, in step 1, the UE may initiate a procedure for activating the multicast service by means of a second activation.

Then, in step 2, the MBS AF entity may feed back response information (Nnef _ MBS AuthorizationRequest Notify Response) of the notification of the MBS authorization request to the NEF entity through the Nnef interface, the response information including the TMGI corresponding to the multicast service and the multicast service session start identifier (Session Start Indicator). The multicast service session start identifier is used for subsequent establishment of a user plane for the UE and corresponding to the multicast service.

Then, in step 3, the NEF entity may feed back response information (Nmbsf _ MBS AuthorizationRequest Notify Response) of the notification of the MBS authorization request to the MBSF entity through the Nmbsf interface, and the response information may include the TMGI corresponding to the multicast service and the multicast service session start identifier.

Then, in step 4, the MBSF entity may feed back response information (Nsmf _ MBS AuthorizationRequest Notify Response) of the notification of the MBs authorization request to the MB-SMF entity through the Nmbsf interface, and the response information may include the TMGI corresponding to the multicast service and the multicast service session start identifier.

Then, in step 5, the MB-SMF entity may create an MBs UE Context for the UE based on the above-mentioned multicast address, and then may feed back a response message (Nsmf _ MBSSession _ CreateMBSUEContext Response) to the AMF entity in response to the request for creating the MBs UE Context sent by the AMF entity to the MB-SMF entity during the activation of the multicast service described in step 1.

Then, in step 6, the MBS AF entity may send a request (Nnef _ MBS SessionStart Request) for requesting to start a multicast service session to the NEF entity through the Nnef interface, the request may include the GPSI of the user equipment, the TMGI corresponding to the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, an ID of the multicast service session, an expected duration of the multicast service session, and a data transmission time of the multicast service. The request includes the GPSI of the user equipment to indicate that this step is an operation for the UE (i.e. one specific UE). In addition, the request includes the service quality requirement of at least one data flow corresponding to the multicast service, so that the PCC technology is applied to the transmission of the multicast service data, and the combination of the PCC and the transmission of the multicast service data is realized.

Then, in step 7, the NEF entity may send a request (Nmbsf _ MBS SessionStart Request) for requesting to start a multicast service session to the MBSF entity through the Nmbsf interface, the request may include a SUPI of the user equipment, a TMGI corresponding to the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, an ID of the multicast service session, an expected duration of the multicast service session, and a data transmission time of the multicast service. The request includes the SUPI of the user equipment to indicate that this step is an operation for the UE (i.e., a particular UE).

Then, in step 8, the MBSF entity may select one MBSU entity from the plurality of MBSU entities according to the S-nsai, DNN corresponding to the multicast service and the multicast address of the multicast service. In addition, MBSF entity may send a request (N4 MBS Session Establishment Request) for MBS session establishment to the selected MBSU entity through the N4 interface, which may include the multicast address of the multicast service. The MBSU entity may establish a GTP user plane tunnel transmission tree from the MBSU entity to the MB UPF entity according to a multicast routing protocol, so as to implement transmission MBSU of data (such as service data corresponding to the multicast service) to be sent by the MB UPF entity in a tree GTP user plane tunnel manner. The MBSU entity may then assign a first tunnel multicast address for transmitting traffic data corresponding to the multicast traffic. Specifically, the MBSU entity may allocate a multicast address of the GTP user plane tunnel through the N6 interface to the multicast service, and take the multicast address of the allocated GTP user plane tunnel as the multicast address of the first tunnel. The MBSU entity may then assign an identification, e.g., common tunnel endpoint identification (Common-Tunnel End point ID, C-TEID), to the multicast traffic. The MBSU entity may then feed back a response message (N4 MBS Session Establishment Response) to the MBSF entity in response to the request for MBS session establishment (N4 MBS Session Establishment Request) sent by the MBSF entity to the MBSU entity. The response information may include the first tunnel multicast address assigned by the MBSU entity and an identification corresponding to the first tunnel multicast address. In addition, for the multicast service, the MBSF entity may record the PCF ID, MBSU ID, the first tunnel multicast address corresponding to the multicast service, and the identification corresponding to the first tunnel multicast address in the MBS UE Context of the UE. If the MBSU entity has been previously allocated and the MBSU entity has also been allocated a first tunnel multicast address and an identification corresponding to the first tunnel multicast address, this step need not be performed, but only the first tunnel multicast address allocated by the MBSU entity and the identification corresponding to the first tunnel multicast address may be recorded in the user equipment multicast service Context (MBS UE Context) of the UE.

Alternatively, the MBSF entity may send a request for MBS session establishment to the selected MBSU entity through the N4 interface, where the request may be denoted as N4 MBS Session Establishment Request and may include the multicast address of the multicast service, the first tunnel multicast address allocated by the MBSF entity, and the identifier corresponding to the first tunnel multicast address, so that the MBSU entity establishes a GTP user plane tunneling tree from the MBSU entity to the MB UPF entity according to a multicast routing protocol, thereby implementing transmission of data (e.g., service data corresponding to the multicast service) that the MBSU entity is to send to the MBUPF entity in a tree-like GTP user plane tunnel. The MBSU entity may then feed back a response message (N4 MBS Session Establishment Response) to the MBSF entity in response to the request for MBS session establishment (N4 MBS Session Establishment Request) sent by the MBSF entity to the MBSU entity. The response information may be an acknowledgement of a request (N4 MBS Session Establishment Request) for MBS session establishment sent by the MBSF entity to the MBSU entity.

Then, in step 9, the MBSF entity may send a request (Npcf _ MBS SessionStart Request) to the respective PCF entity according to the recorded MB-SMF ID, the request may include the SUPI of the user device, the TMGI corresponding to the multicast service, the aggregate maximum rate (e.g. AMBR) corresponding to the multicast service, one MB-SMF ID, information of at least one data flow corresponding to the multicast service, quality of service requirements of the at least one data flow, an ID of the multicast service session, an expected duration of the multicast service session, and a data transmission time of the multicast service. The request includes the SUPI of the user equipment to indicate that this step is an operation for the UE (i.e., a particular UE).

Then, in step 10, the PCF entity may send a request (Nmb-smf_ MBS SessionStart Request) to the corresponding MB-SMF entity according to the MB-SMF ID obtained in step 9, the request may include the SUPI of the user device, the TMGI corresponding to the multicast service, the aggregate maximum rate (e.g. AMBR) corresponding to the multicast service, the quality of service rule of the at least one data flow, the ID of the multicast service session, the expected duration of the multicast service session, and the data transmission time of the multicast service. The request includes the SUPI of the user equipment to indicate that this step is an operation for the UE (i.e., a particular UE). Then, the MB-SMF entity may generate MBs QFI, qoS profile, and N4 QER rule corresponding to each data flow according to the received quality of service rule of at least one data flow corresponding to the multicast service.

Then, in step 11, the MB-SMF entity may determine a corresponding MBs UE Context according to the TMGI, and obtain, according to the determined MBs UE Context, the S-nsai, DNN and the multicast address included in the MBs UE Context. The MB-SMF entity may then select one MB-UPF entity from the plurality of MB-UPF entities based on the acquired S-NSSAI, DNN, and multicast/broadcast address. The MB-SMF entity may then send a request (N4 MBS Session Establishment Request) to the selected MB-UPF entity over the N4 interface for requesting MBS session establishment. The request may include a multicast address of the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, and a quality of service enforcement rule for at least one data flow corresponding to the multicast service. The MB-UPF entity may then establish a GTP user plane tunneling tree from the MB-UPF entity to the RAN according to the multicast routing protocol in accordance with the received request to transport data (e.g., traffic data corresponding to the multicast traffic) to be sent by the MB-UPF entity to the RAN in a tree-like GTP user plane tunnel. The MB-UPF entity may then assign a second tunnel multicast address for transmitting traffic data corresponding to the multicast traffic. Specifically, the MB-UPF entity may allocate a multicast address of the GTP user plane tunnel through the N3 interface for the multicast service, and take the multicast address of the allocated GTP user plane tunnel as the multicast address of the second tunnel. The second type UPF entity may then assign an identification (e.g., C-TEID) for the multicast service. In addition, for multicast service, the MB-SMF entity may record the PCF ID, the MB-UPF ID, a second tunnel multicast address corresponding to the multicast service, and an identification corresponding to the second tunnel multicast address in an MBs UE Context of the UE. This step need not be performed if an MB-UPF entity has been previously allocated and the MB-UPF entity has also been allocated a second tunnel multicast address and an identification corresponding to the second tunnel multicast address, and only the second tunnel multicast address allocated by the MB-UPF entity and the identification corresponding to the second tunnel multicast address may be recorded in the user equipment multicast service Context (MBs UE Context) of the UE.

Alternatively, the MB-SMF entity may send a request for MBs session establishment to the selected MB-UPF entity via the N4 interface (N4 MBS Session Establishment Request), and the request may include the multicast address of the multicast service, the second tunnel multicast address allocated by the MB-SMF entity, and an identification corresponding to the second tunnel multicast address, so that the MB-UPF entity establishes a GTP user plane tunneling tree from the MB-UPF entity to the RAN according to the multicast routing protocol, thereby enabling transmission of data to be sent by the MB-UPF entity to the RAN in a tree-like GTP user plane tunnel (e.g., traffic data corresponding to the multicast service). The MB-UPF entity may then feed back a response message to the MB-SMF entity (N4 MBS Session Establishment Response) in response to the request for MBS session establishment sent by the MB-SMF entity to the MB-UPF entity (N4 MBS Session Establishment Request). The response information may be an acknowledgement of a request (N4 MBS Session Establishment Request) for MBs session establishment sent by the MB-SMF entity to the MB-UPF entity.

Then, in step 12, the MB-SMF entity may send first information (Namf _communication_n1n MESSAGETRANSFER) to the AMF entity through the Namf interface. The first information may include a response (Activate MBS UE Context Response) to activate MBS UE Context, the response to activate MBSUE Context may include a TMGI corresponding to the multicast service, and the MB-SMF entity may encapsulate the "response to activate MBS UE Context" using N1 MBS SM Context. In addition, the first information may further include a TMGI corresponding to the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a second tunnel multicast address corresponding to the multicast service, and an identification corresponding to the second tunnel multicast address. The MB-SMF entity may encapsulate the TMGI corresponding to the multicast service, the quality of service flow identifier and the quality of service profile corresponding to each data flow of the multicast service, the second tunnel multicast address corresponding to the multicast service, and the identifier corresponding to the second tunnel multicast address using the N2 MBs SM Container.

Then, in step 13, the AMF entity may send a request (N2 MBS Session Start Request) to the RAN over the N2 interface for requesting the start of the multicast service session. The request may include a downlink NAS Transport (DLNAS Transport) message, one cell of which is the response (Activate MBS UE Context Response) to activate MBS UE Context described above, encapsulated using N1 MBS SM Context. Through the downlink NAS Transport message, the AMF entity may instruct the RAN to send the DL NAS Transport message directly to the UE. In addition, the request may further include a TMGI corresponding to the multicast service, an aggregate maximum rate (e.g., AMBR) corresponding to the multicast service, a multicast address for the multicast service, a quality of service flow identification and a quality of service profile corresponding to each data flow of the multicast service, a second tunnel multicast address corresponding to the multicast service, and an identification corresponding to the second tunnel multicast address.

The RAN may then send the DL NAS Transport message described above to the UE through RRC signaling in step 14.

The RAN may then send a response (N2 MBS Session Start Response) to the AMF entity over the N2 interface in step 15. The response may be an acknowledgement of N2 MBS Session Start Request sent to the RAN by the AMF entity as described in step 13.

The RAN may then allocate resources for transmitting multicast traffic data to its served UEs to support data flows with different quality of service requirements in step 16.

The RAN may then join the transport group corresponding to the second tunnel multicast address described above in step 17 to receive multicast service data from the MB-UPF entity.

Then, in step 18, the AMF entity may send notification information (Namf _communication_n2 MBSMessageNotify) to the MB-SMF entity through the Namf interface. The notification information may be an acknowledgement of the information sent by the MB-SMF entity to the AMF entity described in step 12 above.

Then, in step 19, the MB-SMF entity may send a response message (Nsmf _ MBS SessionStart Response) to the PCF entity via the Nmb-SMF interface in response to the request sent by the PCF entity to the MB-SMF entity described in step 10.

Then, in step 20, the PCF entity may send a response message (Npcf _ MBS SessionStartResponse) to the MBSF entity via the Npcf interface in response to the request sent to the PCF entity by the MBSF entity described in step 9.

Then, in step 21, MBSF entity can send a response message (Nmbsf _ MBS SessionStart Response) to the NEF entity over the Nmbsf interface in response to the request sent by the NEF entity to the MBSF entity described in step 7.

Then, in step 22, the NEF entity may send a response message (Nnef _ MBS SessionStart Response) to the MBS AF entity through the Nnef interface in response to the request sent by the MBS AF entity to the NEF entity described in step 6 above.

Then, in step 23, the multicast service may be started. The MBS AF entity can send MBS data packet with destination IP address as multicast address of the multicast service to the downstream MBSU entity. The MBSU entity may then send the multicast service data to the MB-UPF entity by the transport layer multicast method described above. The MB-UPF entity may then send MBs packets to the RAN by the transport layer multicast method described above. The RAN may then send MBS data packets to the UE via the resources allocated to the UE.

Furthermore, devices (e.g., UE, RAN, AMF entities, SMF entities, UPF entities, PCF entities, NEF entities, AF entities, etc.) according to embodiments of the present disclosure may also be implemented by means of the architecture of the computing device shown in fig. 13. Fig. 13 illustrates an architecture of the computing device. As shown in fig. 13, computing device 1300 may include a bus 1310, one or more CPUs 1320, a Read Only Memory (ROM) 1330, a Random Access Memory (RAM) 1340, a communication port 1350 connected to a network, an input/output component 1360, a hard disk 1370, and the like. A storage device in computing device 1300, such as ROM 1330 or hard disk 1370, may store various data or files for computer processing and/or communication and program instructions for execution by the CPU. Computing device 1300 can also include a user interface 1380. Of course, the architecture shown in FIG. 13 is merely exemplary, and one or more components of the computing device shown in FIG. 13 may be omitted as may be practical in implementing different devices.

Embodiments of the present disclosure may also be implemented as a computer-readable storage medium. Computer readable storage media according to embodiments of the present disclosure have computer readable instructions stored thereon. When executed by a processor, may perform a method according to embodiments of the present disclosure described with reference to the above figures. The computer-readable storage medium includes, but is not limited to, for example, volatile memory and/or nonvolatile memory. The volatile memory may include, for example, random Access Memory (RAM) and/or cache memory (cache), and the like. The non-volatile memory may include, for example, read Only Memory (ROM), hard disk, flash memory, and the like.

Those skilled in the art will appreciate that various modifications and improvements can be made to the disclosure. For example, the various devices or components described above may be implemented in hardware, or may be implemented in software, firmware, or a combination of some or all of the three.

Furthermore, as shown in the present disclosure and claims, unless the context clearly indicates otherwise, the words "a," "an," "the," and/or "the" are not specific to the singular, but may include the plural. The terms "first," "second," and the like, as used in this disclosure, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Likewise, the word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

Further, a flowchart is used in this disclosure to describe the operations performed by the system according to embodiments of the present disclosure. It should be understood that the preceding or following operations are not necessarily performed in order precisely. Rather, the various steps may be processed in reverse order or simultaneously. Also, other operations may be added to or removed from these processes.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

While the present disclosure has been described in detail above, it will be apparent to those skilled in the art that the present disclosure is not limited to the embodiments described in the present specification. The present disclosure may be embodied as modifications and variations without departing from the spirit and scope of the disclosure, which is defined by the appended claims. Accordingly, the description herein is for the purpose of illustration and is not intended to be in any limiting sense with respect to the present disclosure.

Claims

1. A method performed by a user device, comprising:

Determining an activation mode for activating a multicast service so as to activate the user device and perform the multicast service;

Activating the multicast service according to the determined activation manner and at least through a session management function entity, wherein a multicast service session corresponding to the multicast service is performed during activation of the multicast service and a user plane corresponding to the multicast service is established for the user device during activation of the multicast service, such that the user device performs the multicast service session; and

And receiving service data corresponding to the multicast service.

2. The method of claim 1, prior to the determining the activation manner for activating the multicast service, the method further comprising:

and determining a first identifier and a second identifier corresponding to the multicast service, wherein the first identifier and the second identifier are used for an access and mobility management function entity to select the session management function entity.

3. The method of claim 2, wherein the first identification is used to identify a network segment corresponding to the multicast service and the second identification is used to identify a data network corresponding to the multicast service.

4. A method according to claim 2 or 3, wherein said determining a first identity and a second identity corresponding to said multicast traffic comprises:

Obtaining, from a policy control function entity, a user device routing policy rule corresponding to each of the at least one multicast service, wherein each user device routing policy rule includes at least a multicast address of the corresponding multicast service;

determining a user device routing policy rule corresponding to the multicast service according to the multicast address of the multicast service; and

And determining a first identifier and a second identifier corresponding to the multicast service according to the determined routing policy rule of the user device.

5. A method according to claim 2 or 3, wherein said activating the multicast service according to the determined activation manner and at least by a session management function entity comprises:

Determining a third identification, wherein the third identification is used for identifying a user device multicast service context established for activating the multicast service;

transmitting a request for activating the user device multicast service context to the session management function entity, wherein the request for activating the user device multicast service context comprises the third identifier and a multicast address of the multicast service;

a response to the request for activating the user device multicast service context is received from the session management function entity, the response including a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service is activated.

6. The method of claim 5, wherein sending a request to the session management function entity to activate the user device multicast service context comprises:

A request for activating the user device multicast service context is sent via the access and mobility management function entity to the session management function entity.

7. The method of claim 5, wherein receiving a response from the session management function entity to the request to activate the user device multicast service context comprises:

A response to the request for activating the user device multicast service context is received from the session management function entity via a serving base station of the user device and the access and mobility management function entity.

8. The method of any of claims 5 to 7, prior to said determining a third identity, the method further comprising:

acquiring a first identifier, a second identifier and a multicast address from the session management functional entity;

It is determined whether the obtained first identity is the same as the determined first identity, whether the obtained second identity is the same as the determined second identity, and whether the obtained multicast address is the same as the multicast address of the multicast service.

9. The method of claim 8, prior to obtaining a first identifier, a second identifier, and a multicast address from the session management function entity, the method further comprising:

Acquiring an internet protocol address from the session management function entity according to the first identifier and the second identifier; and

And sending a data packet to a network according to the acquired internet protocol address so as to enable a user plane functional entity in the network to acquire the data packet, wherein the data packet is used for indicating the multicast service which the user device wants to activate.

10. The method according to claim 9, wherein the method comprises,

Wherein obtaining an internet protocol address from the session management function based on the first identification and the second identification comprises:

Selecting the session management function entity and establishing a protocol data unit session according to the first identifier and the second identifier, and acquiring an internet protocol address from the session management function entity; and

Wherein the sending the data packet to the network according to the acquired internet protocol address so that the user plane function entity in the network acquires the data packet comprises:

Transmitting a data packet to a network according to the acquired internet protocol address so that a user plane functional entity participating in the establishment of the protocol data unit session in the network acquires the data packet;

wherein the destination address of the data packet is or the protocol part of the data packet comprises the multicast address of the multicast service.

11. A method performed by a session management function entity, comprising:

Receiving a request from a user device for activating a user device multicast service context established by the user device for activating a multicast service, the request for activating the user device multicast service context including a third identification for identifying the user device multicast service context and a multicast address of the multicast service;

Determining a response to the request for activating a user device multicast service context, wherein the response includes a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service requested by the user device is activated;

obtaining a fifth identifier corresponding to the multicast service, wherein the fifth identifier is used for identifying the start of a multicast service session corresponding to the multicast service; and

Conducting the multicast service session and transmitting the response to the user device,

Wherein a multicast service session corresponding to the multicast service is performed during activation of the multicast service requested by the user device.

12. The method of claim 11, wherein the receiving a request from a user device to activate a user device multicast service context comprises:

a request for activating a user device multicast service context is received from the user device via an access and mobility management function entity.

13. The method of claim 11 or 12, wherein sending the response to the user device comprises:

The response is sent to the user device via the serving base station of the user device and an access and mobility management function entity.

14. The method of claim 11 or 12, prior to the receiving a request from a user device to activate the user device multicast service context, the method further comprising:

establishing a protocol data unit session;

Assigning an internet protocol address to said user device;

Acquiring a multicast address of a multicast service to be activated by the user equipment from a user plane function entity participating in the establishment of the protocol data unit session, wherein the multicast address is acquired after the user equipment transmits a data packet to a network including the user plane function entity according to the internet protocol address, wherein the data packet is used for indicating the multicast service to be activated by the user equipment;

When the session management function entity decides to instruct the user device to activate the multicast service, sending a request for instructing the user device to activate the multicast service to the user device, wherein the request for instructing the user device to activate the multicast service includes an identifier corresponding to the multicast service to be activated by the user device and a multicast address of the multicast service, wherein the identifier corresponding to the multicast service to be activated by the user device is used for an access and mobility management function entity to select the session management function entity.

15. The method of claim 12, further comprising:

A dedicated identity of the user equipment and an identity of a serving base station of the user equipment are received from the access and mobility management function entity.

16. The method of claim 15, further comprising:

the identity of the serving base station of the user device is recorded in the user device multicast service context in order to obtain the identity of the serving base station of all user devices that activate the multicast service by the session management function entity.

17. The method of claim 11, wherein determining a response to the request to activate a user device multicast service context comprises:

determining whether the user device is capable of using the multicast service;

when the user device is capable of using the multicast service, sending a notification to an application function entity, wherein the notification is a notification of an authorization request for the multicast service; and

A response to the notification is received from the application function entity, wherein the response to the notification includes a fourth identification corresponding to the multicast service.

18. The method of claim 17, wherein the notification includes at least an identification corresponding to a multicast service to be activated by the user device, a multicast address of the multicast service, and an identification of the session management function entity, wherein the identification corresponding to the multicast service to be activated by the user device is used for access and mobility management function entity selection of the session management function entity, the identification of the session management function entity facilitating the application function entity to obtain session management function entities involved in activating the multicast service by all user devices to be activated by the multicast service.

19. The method of claim 17 or 18, wherein sending a notification to the application function entity comprises:

A notification is sent to the application function entity via the network opening function entity.

20. The method of claim 19, wherein the notification further comprises an identification of the application function entity such that the network open function entity determines the application function entity from the identification of the application function entity and sends the notification to the application function entity.

21. The method of claim 17, wherein receiving a response to the notification from the application function entity comprises:

A response to the notification is received from the application function entity via a network open function entity.

22. The method of claim 11, wherein conducting the multicast service session comprises:

A first request is received from a policy control function entity, wherein the first request is used for requesting the start of the multicast service session, and the first request at least comprises a first identifier of the user device, a fourth identifier corresponding to the multicast service, a service quality rule of at least one data flow corresponding to the multicast service, and an identifier of the multicast service session, wherein the first identifier is used for identifying a network fragment corresponding to the multicast service.

23. The method of claim 22, wherein the first request is determined by the policy control function based on a second request received from a network opening function or an application function requesting the start of a multicast traffic session from the policy control function by the network opening function or the application function.

24. The method of claim 23, wherein the second request includes at least a first identification of the user device, the fourth identification, an identification of the session management function entity, information of at least one data flow corresponding to the multicast service, a quality of service requirement of the at least one data flow, and an identification of the multicast service session.

25. The method of claim 24, wherein the policy control function is determined by the network opening function or the application function based on an identification of the session management function.

26. The method of claim 23, wherein the second request is determined by the network opening function entity based on a third request received from an application function entity for the application function entity to request a start of a multicast traffic session from the network opening function entity.

27. The method of claim 26, wherein the third request includes at least a second identification of the user device, the fourth identification, information of at least one data flow corresponding to the multicast service, quality of service requirements of the at least one data flow, and an identification of the multicast service session.

28. The method of claim 22, wherein conducting the multicast service session further comprises:

and generating a service quality flow identifier, a service quality configuration file and a service quality execution rule corresponding to each data flow according to the service quality rule of each data flow.

29. The method of claim 28, wherein conducting the multicast service session further comprises:

Selecting a user plane function entity according to the fourth identifier;

Transmitting a fourth request to the selected user plane function entity, wherein the fourth request is used for establishing transmission resources of the multicast service session; and

Obtaining a response to the fourth request from the selected user plane functional entity, wherein the response to the fourth request comprises a tunnel multicast address allocated by the selected user plane functional entity for transmitting service data corresponding to the multicast service, and a sixth identifier corresponding to the tunnel multicast address, wherein the tunnel multicast address is used for multicast tunneling between network entities, and the sixth identifier is used for identifying a transmission tunnel of the multicast service.

30. The method of claim 28, wherein conducting the multicast service session further comprises:

Selecting a user plane function entity according to the fourth identifier;

Transmitting a fourth request to the selected user plane functional entity, wherein the fourth request is used for establishing transmission resources of the multicast service session, the fourth request comprises a tunnel multicast address allocated by the session management functional entity for transmitting service data corresponding to the multicast service, and a sixth identifier corresponding to the tunnel multicast address, wherein the tunnel multicast address is used for multicast tunneling between network entities, and the sixth identifier is used for identifying a transmission tunnel of the multicast service;

A response to the fourth request is obtained from the selected user plane function entity.

31. The method according to claim 29 or 30, wherein the fourth request comprises at least a multicast address of the multicast service, a quality of service enforcement rule for the at least one data flow, and an aggregate maximum rate corresponding to the multicast service.

32. The method of claim 29 or 30, further comprising:

At least the tunnel multicast address and the sixth identification are recorded in respective user device multicast service contexts in which the multicast service has been activated.

33. The method of claim 29 or 30, wherein the conducting the multicast service session and sending the response to the user device comprises:

Transmitting first information to an access and mobility management function entity, wherein the first information comprises the response and information related to the multicast service session, such that the access and mobility management function entity transmits a fifth request to a corresponding serving base station according to the information related to the multicast service session, and transmits the response to the user equipment via the corresponding serving base station, wherein the fifth request is for requesting a start of the multicast service session.

34. The method of claim 33, wherein the information related to the multicast traffic session includes at least the fourth identification, an aggregate maximum rate corresponding to the multicast traffic, quality of service flow identifications and quality of service profiles corresponding to respective data flows, the tunnel multicast address, and the sixth identification.

35. The method of claim 26 or 27, wherein any of the first request, the second request, and the third request further comprises an aggregate maximum rate corresponding to the multicast traffic.

36. A user device, comprising:

A determining unit configured to determine an activation manner for activating a multicast service, so as to activate the user device and perform the multicast service;

An activation unit configured to activate the multicast service according to the determined activation manner and at least through a session management function entity, wherein a multicast service session corresponding to the multicast service is performed during activation of the multicast service, and a user plane corresponding to the multicast service is established for the user device during activation of the multicast service, such that the user device performs the multicast service session; and

And a receiving unit configured to receive service data corresponding to the multicast service.

37. A session management functional entity comprising:

A receiving unit configured to receive a request from a user device for activating a user device multicast service context, the user device multicast service context being established for activating a multicast service, the request for activating the user device multicast service context comprising a third identification for identifying the user device multicast service context and a multicast address of the multicast service;

A determining unit configured to determine a response to the request for activating a user device multicast service context, wherein the response comprises a fourth identification corresponding to the multicast service, wherein the fourth identification is used by the user device to determine whether the multicast service requested by the user device is activated;

An obtaining unit configured to obtain a fifth identifier corresponding to the multicast service, where the fifth identifier is used to identify a start of a multicast service session corresponding to the multicast service;

a control unit configured to conduct the multicast service session; and

A transmitting unit configured to transmit the response to the user device,

38. A user device, comprising:

a processor; and

A memory, wherein the memory has stored therein a computer executable program which, when executed by the processor, performs the method of any of the preceding claims 1-10.

39. A session management functional entity comprising:

a processor; and

A memory, wherein the memory has stored therein a computer executable program which, when executed by the processor, performs the method of any of the preceding claims 11-35.