Multicast or broadcast session establishment and management

Abstract

Methods, apparatuses, and systems are disclosed for providing flexible multicast or broadcast session establishment and management. In one example aspect, a method of wireless communication is disclosed. The method includes receiving, by a broadcast and multicast service center function, a request to establish a multicast or broadcast session for an application function. The request includes information representing a target area of a multicast or broadcast service associated with the multicast or broadcast session. The method further includes determining, by the broadcast and multicast service center function, at least one access and mobility management function based on the information; and sending, by the broadcast and multicast service center function, a session trigger message to the at least one access and mobility management function to allow the at least one access and mobility management function to initiate establishment of the multicast or broadcast session.

Description

TECHNICAL FIELD

[0001] The present patent document generally relates to wireless communication. BACKGROUND

[0002] Mobile communication technology is pushing the world towards an increasingly interconnected and networked society. The rapid growth of mobile communications and advances in technology have led to greater demands for capacity and connectivity. Other aspects, such as energy consumption, device cost, spectral efficiency, and latency, are also important to meet the needs of various communication scenarios. Various techniques are being discussed, including new approaches that provide higher quality of service, longer battery life, and improved performance. SUMMARY

[0003] This patent document generally describes techniques to enable flexible multicast or broadcast session establishment and management in different scenarios. The disclosed techniques can be used to manage a multicast session regardless of when a User Equipment (UE) requests to join the multicast session. The disclosed techniques can also be used in various deployment scenarios, for example, when a Broadcast and Multicast Service Center (BMSC) is deployed as a separate function or in a distributed manner with other network functions.

[0004] In one example aspect, a method of wireless communication is disclosed. The method includes receiving, by a broadcast and multicast service center function, a request to establish a multicast or broadcast session for an application function. The request includes information representing a target area of multicast or broadcast service associated with the multicast or broadcast session. The method further includes determining, by the broadcast and multicast service center function, at least one access and mobility management function based on the information; and sending, by the broadcast and multicast service center function, a PDU session trigger message to the at least one access and mobility management function to allow the at least one access and mobility management function to initiate establishment of the multicast or broadcast session.

[0005] In another example aspect, a method of wireless communication is disclosed. The method includes receiving, by an access and mobility management function from a network communication node, a session trigger message triggering establishment of a multicast or broadcast session. The session trigger message includes an identifier identifying a multicast or broadcast service associated with the multicast or broadcast session. The method further includes sending, by the access and mobility management function, a request to establish the multicast or broadcast session to a session management function.

[0006] In another example aspect, a method of wireless communication is disclosed. The method includes receiving, by a base station, a message from a communication node in a core network, where the message includes an identifier that identifies a multicast or broadcast service for which a mobile device is authorized to receive data; and receiving, by the base station from the communication node, a request to establish a multicast or broadcast session for the multicast or broadcast service. The request includes the identifier that identifies the multicast or broadcast service and a quality of service profile for the multicast or broadcast session. The method includes transmitting, by the base station to the mobile device that is authorized to receive data for the multicast or broadcast service, a message that indicates a resource configuration for the multicast or broadcast session. The resource configuration is determined based in part on the quality of service profile associated with the multicast or broadcast session. The method also includes transmitting, by the base station, data for the multicast or broadcast session using resources configured according to the resource configuration.

[0007] In another example aspect, a communication apparatus is disclosed. The apparatus includes a processor configured to implement the above-described methods.

[0008] In yet another example aspect, a computer program storage medium is disclosed. The computer program storage medium has code stored thereon, the code, when executed by a processor, causes the processor to implement the described methods.

[0009] These and other aspects are described in the present document. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 An example architecture of a 5G Multimedia Broadcast Multicast Service (MBMS) system is illustrated.

[0011] Figure 2 An example signaling sequence for establishing a unicast Packet Data Unit (PDU) session is illustrated.

[0012] Figure 3 An example architecture of an interface showing a unicast session and a multicast or broadcast session in accordance with the present technology is illustrated.

[0013] Figure 4 An example flow diagram of a method of wireless communication in accordance with the present technology is illustrated.

[0014] Figure 5 An example flow diagram of another method of wireless communication in accordance with the present technology is illustrated.

[0015] Figure 6 An example flow diagram of yet another method of wireless communication in accordance with the present technology is illustrated.

[0016] Figure 7FIG. illustrates an example signaling sequence for requesting Multicast or Broadcast Service (MBS) configuration according to the present technology.

[0017] Figure 8 FIG. illustrates an example signaling sequence for user equipment accessing MBS according to the present technology.

[0018] Figure 9 FIG. illustrates an example signaling sequence for establishing MBS session according to the present technology.

[0019] Figure 10 FIG. illustrates another example signaling sequence for establishing MBS session according to the present technology.

[0020] Figure 11 FIG. illustrates an example signaling sequence for configuring radio resources for MBS session according to the present technology.

[0021] Figure 12 FIG. illustrates an example of a wireless communication system to which techniques according to one or more embodiments of the present technology can be applied.

[0022] Figure 13 is a block diagram representation of a portion of a radio station to which one or more embodiments of the present technology can be applied. DETAILED DESCRIPTION

[0023] The use of section headings in this document is merely for readability and does not limit the scope of the embodiments and techniques disclosed in each section to the sections. Examples of fifth generation (5G) wireless protocols are used to describe certain features. However, the applicability of the disclosed techniques is not limited to 5G wireless systems.

[0024] Multimedia Broadcast / Multicast Service (MBMS) can refer to a network architecture in which network resources are used to send (e.g., broadcast) the same multimedia content to everyone or send (e.g., multicast) the same multimedia content to a group of subscribers, rather than sending the content individually to each subscriber (e.g., unicast). With the development of 5G New Radio (NR) technology, MBMS can provide operational efficiency for Internet of Things (IoT) and Vehicle to Everything (V2X) communications. Figure 1 FIG. illustrates an example architecture of a 5G Multimedia Broadcast Multicast Service (MBMS) system 100. System 100 includes the following functions:

[0025] 1.1. User Equipment (UE) 101, such as a cell phone, tablet, or other mobile device.

[0026] 1.2. Radio Access Network (RAN) 103, e.g., a base station.

[0027] 1.3. Access and mobility Management Function (AMF) 105. This function handles the following functionalities: registration management, connection management, reachability management and mobility management. It also performs access authentication and access authorization. The AMF is the Non-Access Stratum (NAS) security anchor point and relays NAS signaling between the UE and other network nodes, e.g., the Session Management Function (SMF).

[0028] 1.4. Session Management Function (SMF) 107. This function handles the following functionalities: session establishment, modify and release, UE Internet Protocol (IP) address allocation and management (including optional authorization functionality), selection and control of the uplink function, downlink data notification, etc.

[0029] 1.5. User Plane Function (UPF) 109. This function handles the following functionalities: acting as an anchor point for intra- / inter-Radio Access Technology (RAT) mobility, packet data routing and forwarding, traffic usage reporting, Quality of Service (QoS) handling for user plane traffic, downlink packet data buffering, and downlink data notification triggering, etc.

[0030] 1.6. Network Repository Function (NRF) 111. The NRF stores NF profiles of available Network Function (NF) instances and supported services. The NRF also supports service discovery functionality. A new network function instance registers its NF profile in the NRF after startup, so that other network functions can discover the new network function instance by querying the NRF.

[0031] 1.7. Unified Data Management (UDM) 113. The UDM supports UE registration and subscription management (e.g., storing service AMF for a UE, storing service SMF for a UE’s packet data unit (PDU) session). To provide this functionality, the UDM uses subscription data (including authentication data) that can be stored in a Unified Data Repository (UDR).

[0032] 1.8. Unified Data Repository (UDR) 115. The UDR supports storage and retrieval of subscription data by the UDM, storage and retrieval of policy data by the Policy Control Function (PCF), storage and retrieval of structured data for exposure, etc.

[0033] 1.9. Network Exposure Function (NEF) 117. The NEF supports exposure of capabilities and events of the network to Application Functions. Third party Application Functions can invoke services offered by the network via the NEF, and the NEF performs authentication and authorization of third party applications. The NEF also provides translation of information exchanged with AFs and information exchanged with internal network functions.

[0034] 1.10. Application Function (AF) 119. The AF interacts with the Third-Generation Partnership Project (3GPP) core network in order to provide services, e.g., application influence on traffic routing, access to network exposure functions, interaction with the policy framework for policy control, etc. Operator trusted AFs are allowed to interact directly with relevant network functions. Operator untrusted application functions interact with relevant network functions using the external exposure framework through the NEF.

[0035] 1.11. Policy Control Function (PCF) 121. The PCF supports a unified policy framework to govern network behavior. The PCF provides access management policies to AMFs, session management policies to SMFs, or UE policies to UEs. The PCF can access the UDR to obtain subscription information relevant to policy decisions.

[0036] 1.12. Broadcast and Multicast Service Center (BMSC). In 5G communication systems, the BMSC is deployed to provide multicast or broadcast service (MBS) sessions to application functions. In some embodiments, the BMSC's control plane functions (BMSC-C 123) and user plane functions (BMSC-U 125) can be coupled and / or deployed together. In some embodiments, BMSC-C is decoupled from BMSC-U. BMSC-C and SMF can be deployed together, while BMSC-U and UPF can be deployed together.

[0037] Figure 2 The illustration shows an example signaling sequence used to establish a unicast PDU session.

[0038] 2.1. The UE requests the PDU session establishment process by sending a NAS message, which contains a PDU session establishment request within the N1 SM container. The PDU session establishment request includes the PDU session identifier (ID), the requested PDU session type, the requested Single-Network Slicing Selection Assistant Information (S-NSSAI) indicating the network slice, and the requested Data Network Name (DNN), etc.

[0039] 2.2. The AMF sends an Nnrf_NFDiscovery_Request containing relevant parameters to the NRF.

[0040] 2.3. NRF returns a first list of SMF profiles that match the requested S-NSSAI and the requested DNN. The SMF profiles also include the SMF service area for each SMF.

[0041] 2.4. The AMF sends an Nsmf_PDUSession_CreateSMContext request to the selected SMF. This message includes the user's permanent identifier (SUBscription Permanent Identifier, SUPI), DNN, S-NSSAI, PDU session ID, AMF ID, request type, N1 SM container containing the PDU session establishment request, user location information, etc.

[0042] 2.5. The SMF selects a UPF for a PDU session. The SMF establishes an N4 association with the selected UPF. N3 tunnel information is allocated by the UPF and provided to the SMF.

[0043] 2.6. SMF returns the Nsmf_PDUSession_CreateSMContext response. This message contains a reason value indicating whether the request was accepted. The message also includes the SM context ID assigned by SMF. AMF can use the SM context ID for subsequent messages to SMF.

[0044] 2.7. The SMF sends a Namf_Communication_N1N2MessageTransfer to the AMF. This message includes parameters such as the PDU session ID, N2 SM information (e.g., PDU session ID, QoS Flow ID (QFI), QoS profile, UPF N3 tunnel information, S-NSSAI, etc.), and an N1 SM container containing PDU session establishment acceptance (e.g., QoS rules, S-NSSAI, DNN, etc.). The AMF sends a response to the SMF.

[0045] 2.8. The AMF sends an N2 PDU session request to the RAN. This message includes N2 SM information, a NAS message such as the PDU session ID, and an N1 SM container containing the PDU session establishment acceptance.

[0046] 2.9. The RAN can publish Access Network (AN) specific signaling exchanges for interaction with the UE, which are related to information received from the SMF. For example, it can perform Radio Resource Control (RRC) connection reconfiguration with the UE to establish the necessary NG-RAN resources related to the QoS profile requested by the PDU session. The RAN also allocates N3 tunnel information for the PDU session.

[0047] 2.10. The RAN sends an N2 PDU session response to the AMF. This message includes parameters such as the PDU session ID, reason, and N2 SM information (e.g., PDU session ID, N3 tunnel information, list of accepted / rejected QFIs, etc.).

[0048] 2.11. The AMF sends an Nsmf_PDUSession_UpdateSMContext request to the SMF, which includes the SMF SM context ID, N2 SM information, request type, etc.

[0049] 2.12. The SMF initiates an N4 session modification procedure to the UPF to provide N3 tunnel information received from the RAN.

[0050] 2.13. SMF sends an Nsmf_PDUSession_UpdateSMContext response to AMF.

[0051] 2.14. The SMF sends Nsmf_PDUSession_SMContextStatusNotify to the AMF so that the AMF knows that the PDU session has been successfully established and maintains the mapping between the PDU session ID and the SMF ID.

[0052] According to Figure 2 The signaling sequence shown establishes a unicast PDU session. However, this signaling sequence is not suitable for MBS sessions because an MBS session is shared by a group of UEs and one or more mobile devices. An MBS session can be established before a UE in the group joins the session. Alternatively, the establishment of an MBS session can be initiated after a UE indicates that it wants to join the session. This patent document discloses various techniques that can be implemented to achieve MBS session establishment and management in various scenarios.

[0053] Figure 3 The illustration shows an example architecture 300, illustrating the interfaces of a unicast session 301 and an MBS session 303 according to this technology. Figure 3 As shown, the RAN provides both unicast and MBS services to the UE. The UE can access unicast services via AMF1, PCF1, SMF1, and UPF1 using unicast PDU sessions. Simultaneously, the UE can access MBS services via AMF2, PCF2, SMF2, and UPF2 using MBS sessions. An MBS session can be shared by a group of UEs via a single N3 tunnel between the RAN and UPF2.

[0054] Figure 4 An example flowchart of a method 400 for wireless communication according to the present technology is illustrated. Method 400 includes, at operation 410, receiving a request from a broadcast and multicast service center function to establish an MBS session for an application function. The request includes information indicating a target area of ​​MBS services associated with the MBS session. Method 400 includes, at operation 420, determining at least one access and mobility management function based on the information. Method 400 includes, at operation 430, sending a session trigger message from the broadcast and multicast service center function to the at least one access and mobility management function to allow the at least one access and mobility management function to initiate the establishment of an MBS session.

[0055] In some embodiments, the information representing the target area of ​​the MBS service includes a list of Tracking Area Identifiers (TAIs). In some embodiments, the request also includes an identifier that identifies the MBS service associated with the MBS session. In some embodiments, the session trigger message includes an identifier that identifies the MBS service and a first Internet Protocol (IP) multicast address associated with that identifier.

[0056] Figure 5An example flowchart of a method 500 for wireless communication according to the present technology is illustrated. Method 500 includes, at operation 510, receiving a session trigger message from a network communication node by an access and mobility management function, triggering the establishment of an MBS session. The session trigger message includes an identifier identifying an MBS service associated with the MBS session, such as a Temporary Mobile Group Identity (TMGI). Method 500 includes, at operation 520, sending a request to a session management function to establish an MBS session by the access and mobility management function. In some embodiments, the network communication node includes a broadcast and multicast service center function. In some embodiments, the network communication node includes a network open function. In some embodiments, the session trigger message includes an IP multicast address associated with the identifier identifying the MBS session. In some embodiments, the access and mobility management function receives a response indicating the establishment of an MBS session. The response includes a PDU session ID, assigned by the session management function to identify the MBS session.

[0057] Figure 6 A sample flowchart of a method 600 for wireless communication according to the present technology is illustrated. Method 600 includes, at operation 610, a base station receiving a message from a communication node in a core network. The message includes an identifier that identifies an MBS service for which a UE is authorized to receive its data, such as a Temporary Mobile Group Identifier (TMGI). Method 600 includes, at operation 620, a request from the base station to establish an MBS session for the MBS service from the communication node. The request includes an identifier identifying the MBS service and a service quality profile for the MBS session. Method 600 includes, at operation 630, a message sent by the base station to a mobile device authorized to access the MBS service. The message indicates a resource configuration for the MBS session. This resource configuration is determined in part based on the service quality profile associated with the MBS session. Method 600 also includes, at operation 640, a transmission of MBS session data by the base station using resources configured according to the resource configuration.

[0058] In some embodiments, resource configuration includes peer-to-peer resource configuration. In some embodiments, peer-to-peer resource configuration is used when the mobile device is connected. In some embodiments, resource configuration includes peer-to-multipoint resource configuration. In some embodiments, peer-to-multipoint resource configuration is used when the mobile device is idle. In some embodiments, resource configuration is further determined based on the number of mobile devices interested in accessing MBS services.

[0059] As further described in this document, the above method enables flexible MBS session establishment and management in different scenarios. Several examples of the disclosed technology are further described in the following example embodiments.

[0060] Example 1

[0061] Figure 7 The illustration depicts an example signaling sequence 700 for requesting MBS configuration according to the present technology. MBS configuration includes a Temporary Mobile Group Identifier (TMGI) and an associated IP multicast address. The TMGI is used to uniquely identify the MBS service on the radio interface. The IP multicast address is used to identify the MBS service at the IP layer. In this example, the BMSC's control plane and user plane are coupled or co-located.

[0062] 7.1.AF sends a TMGI request message to NEF to request BMSC to allocate one or more TMGIs to it. The TMGI request includes the number of TMGIs requested.

[0063] 7.2. Whether NEF authorization allows AF to request TMGI. If so, NEF will forward the TMGI request to BMSC.

[0064] 7.3. The BMSC allocates a set of TMGIs, each TMGI associated with an IP multicast address. The BMSC determines the expiration time of the TMGIs. The BMSC returns the set of TMGIs and the associated IP multicast address to the NEF in the TMGI response.

[0065] 7.4. NEF forwards the TMGI response to AF.

[0066] 7.5. The AF initiates the provision of MBS services in the network. The AF sends an AF request to the NEF. The AF request includes application information, S-NSSAI and DNN, TMGI, IP multicast address, and / or target ID. The target ID identifies the UE group that can receive MBS services. For multicast services, the target ID can identify the external group ID. For broadcast services, the target ID can identify any UE. The message may also include information indicating the location of UEs that have joined the MBS service, thereby determining the target area for the MBS service at the start of the MBS session.

[0067] 7.6. For multicast services, NEF maps target IDs (e.g., external group IDs) to internal group IDs. NEF stores the internal group IDs and AF request information in the UDR.

[0068] 7.7. If PCF1 has already subscribed to AF request information from UDR, UDR sends a notification message to PCF1 including the internal group ID and new AF request information. PCF1 then uses the AF request information to generate a new UE policy. The new UE policy represents the IP multicast address of the MBS service. The new UE policy also indicates which S-NSSAI and DNN can be used for unicast PDU sessions, through which the UE can join the MBS service identified by the IP multicast address.

[0069] 7.8. The UE performs the UE registration process with the network. This operation can be performed before operation 7.7.

[0070] 7.9. During UE registration, AMF1 establishes a UE policy association with PCF1. AMF1 retrieves the UE internal group ID that the UE is subscribed to from the UDM. AMF1 provides the UE internal group ID to PCF1.

[0071] 7.10. If the UE registration is accepted, AMF1 sends a registration acceptance message to the UE.

[0072] 7.11. PCF1 checks the UE's internal group ID and determines whether the UE policy needs to be updated. If so, PCF1 sends a Namf_Communication_N1N2MessageTransfer service operation to AMF1, including the new UE policy.

[0073] 7.12. AMF1 sends a UE configuration update command to the UE, including the new UE policy.

[0074] 7.14. The UE stores the new UE policy and sends a UE configuration update completion message to AMF1.

[0075] 7.15. AMF1 sends Namf_Communication_N1MessageNotify to PCF1 to notify the UE that the new UE policy has been successfully stored.

[0076] Example 2

[0077] Figure 8 The illustration shows an example signaling sequence 800 for a UE to access a multicast service according to the present technology. In this example, the network first authorizes whether the UE can access the multicast service. This example procedure can be performed before the multicast session begins.

[0078] 8.1. The UE can obtain an IP multicast address through application layer information exchange. When the UE wants to access a multicast service, it sends an Internet Group Management Protocol (IGMP) join message with the target IP multicast address. This message identifies the multicast service at the IP layer. The UE checks its UE policy to determine the S-NSSAI and DNN associated with the IP multicast address and to see if there is an existing PDU session associated with the S-NSSAI and DNN. If no PDU session is found, the UE first establishes a unicast PDU session with the associated S-NSSAI and DNN. This unicast PDU session is associated with the multicast service. During the PDU session establishment, SMF1 establishes an SM policy association with PCF1 and also provides PCF1 with the UE's internal group ID.

[0079] 8.2. The UE sends an IGMP join message through the user plane of the unicast PDU session associated with the multicast service.

[0080] 8.3. UPF1 detects IGMP join messages and reports the detected IP multicast addresses to SMF1.

[0081] 8.4. SMF1 sends an SM policy association update request containing the IP multicast address to PCF1.

[0082] 8.5. PCF1 already possesses the information received from the UDR regarding the internal group ID and the corresponding IP multicast address. Therefore, PCF1 can check whether the UE's internal group ID matches the internal group ID of the IP multicast address. If so, it authorizes the UE to access the multicast service, and PCF1 returns an SM policy association update response message to SMF1. This message includes the IP multicast address and the associated TMGI.

[0083] 8.6. SMF1 stores the authorized IP multicast address and associated TMGI in the UE context. Then, SMF1 sends Namf_Communication_N1N2MessageTransfer to AMF1, where the N1 message container (e.g., a PDU session modification command) includes the TMGI and IP multicast address. The N2 message container also includes the TMGI.

[0084] 8.7. AMF1 sends the N2 PDU session request along with the N1 message container and the N2 message container to the RAN. The N2 message container also includes the TMGI.

[0085] 8.8. The RAN uses Access Network (AN) specific signaling to send N1 message containers to the UE. The UE knows it is permitted to access multicast services identified by the TMGI. The RAN also stores the TMGI in the UE context, so the RAN knows the UE is permitted to receive multicast services. Multicast services are identified by the TMGI.

[0086] 8.9. RAN returns an N2 PDU session response to AMF1.

[0087] 8.10. AMF1 sends Nsmf_PDUSession_UpdateSMContextRequest to SMF1.

[0088] 8.11. SMF1 sends Nsmf_PDUSession_UpdateSMContextResponse to AMF1.

[0089] The UE is then authorized to access a multicast service identified by a TMGI, which is associated with an IP multicast address. When the UE enters the idle state, the UE context in the RAN is released. However, when the UE enters the connected state, the SMF again provides the authorized TMGI to the RAN. During handover between RAN nodes, the authorized TMGI is also provided to the target RAN within the UE context.

[0090] PCF1 also subscribes to the UE's location from the AMF. When the UE's location changes, the AMF can report the current UE location to PCF1. PCF1 then reports the UE's location to the AF. Based on the UE's location within the group, the AF can use the UE's location to determine the new target area for the multicast session. The AF can send BMSCs to modify the multicast session, such as adding a new N3 tunnel to a RAN node in the new target area, or removing an N3 tunnel to a RAN node outside the new target area.

[0091] Example 3

[0092] Figure 9 The illustration depicts an example signaling sequence 900 for establishing an MBS session according to the present technology. In this example, SMF2 is deployed together with BMSC-C, while UPF2 is deployed together with BMSC-U. After the example procedure is completed, the RAN can receive MBS downlink data via the shared N3 tunnel of the MBS session.

[0093] 9.1. The AF invokes a NEF service operation via an AF request. The content of this service operation (e.g., an AF request) includes the AF transaction ID, the requested S-NSSAI, the requested DNN, and the requested session and service continuity (SSC) mode. These parameters are used to establish an MBS session. This content also includes the TMGI, IP multicast address, and / or the target area serving the MBS session.

[0094] 9.2. NEF authorization: Does it allow AF to start an MBS session? NEF converts the target area into a TAI list and forwards the session start to the BMSC-C deployed with SMF2.

[0095] 9.3. The unified BMSC-C / SMF2 deployment creates an MBS session context associated with the TMGI. Based on local configuration, the BMSC-C / SMF2 assigns a PDU session ID. The PDU session ID can identify not only unicast PDU sessions but also MBS sessions. The BMSC-C / SMF2 selects PCF2 to establish an SM policy association. The BMSC-C / SMF2 also sends the TMGI and IP multicast addresses to PCF2.

[0096] 9.4. BMSC-C / SMF2 selects a BMSC-U / UPF2 that supports MBS sessions. BMSC-C / SMF2 establishes an N4 association with the selected BMSC-U / UPF2. BMSC-C / SMF2 sends forwarding rules, including IP multicast addresses, to BMSC-U / UPF2, allowing UPF2 to forward downlink MBMS traffic to the RAN via the shared N3 tunnel. The shared N3 tunnel information is allocated by BMSC-U / UPF2 and provided to BMSC-C / SMF2.

[0097] 9.5. BMSC-C / SMF2 discovers AMF2 based on the TAI list received in Operation 9.2. BMSC-C / SMF2 sends Namf_Communication_N1N2MessageTransfer to AMF2. This message includes parameters such as PDU session ID, TAI list, N2 SM information (e.g., PDU session ID), TMGI, QFI, QoS profile, N3 tunnel information of BMSC-U / UPF2, S-NSSAI, etc. Because the PDU session is not a unicast session for a single UE, BMSC-C / SMF2 does not need to send an N1 container message. AMF2 then sends a response to BMSC-C / SMF2.

[0098] BMSC-C / SMF2 can select multiple AMF2s based on the TAI list. Operation 9.5 can be performed on each selected AMF2.

[0099] 9.6. AMF2 selects the RAN node list based on the TAI list received in Operation 9.5. Then, AMF2 sends an N2 PDU session request to each RAN node. This request carries the AMF NGAP UE ID, TMGI, and N2 SM information received from BMSC-C / SMF2.

[0100] AMF2 can select multiple RAN nodes based on the TAI list. Operation 9.6 can be performed on each selected RAN node.

[0101] 9.7. The RAN creates an MBS session context associated with the TMGI and can reserve AN-specific resources for the MBS session. The RAN can begin broadcasting the TMGI via the air (User Equipment to the UMTS Terrestrial Radio Access Network, Uu) interface. By obtaining the TMGI in the broadcast information, the UE determines whether it can access the RAN node to receive the MBS service associated with that TMGI.

[0102] In some embodiments, the RAN may reserve AN-specific resources at a later stage. When no UE is interested in MBS services under this cell, the RAN does not need to allocate MBS resources for MBS services. When the RAN receives downlink packet data through the N3 tunnel, the RAN may discard these packet data because no radio resources have been reserved.

[0103] The RAN sends an N2 PDU session response to AMF2. This message includes a newly assigned RAN NGAP UE ID (NGAP stands for Next Generation Application Protocol). AMF2 uses the RAN NGAP UE ID in subsequent N2 messages to the RAN node to modify the MBS session. This message may also include parameters such as the PDU session ID, reason, N2 SM information (e.g., PDU session ID, N3 tunnel information, and the accepted / rejected QFI list).

[0104] 9.8. For each RAN response, AMF2 sends an Nsmf_PDUSession_UpdateSMContext request to BMSC-C / SMF2, which includes the PDU session ID and N2 SM information.

[0105] 9.9. For each request received from AMF2, BMSC-C / SMF2 initiates an N4 session modification procedure to BMSC-U / UPF2 to provide the N3 tunnel information received from the RAN node. BMSC-U / UPF2 then associates each N3 tunnel information from the RAN node with the MBS session.

[0106] If multiple RANs are associated with an MBS session, the BMSC-U / UPF2 replicates the MBS downlink traffic and forwards it to each RAN node via the corresponding N3 tunnel.

[0107] If BMSC-U / UPF2 does not assign a BMSC-U IP address and port number to the MBS session, then BMSC-U / UPF2 will assign a BMSC-U IP address and / or port number to the MBS session and provide it to BMSC-C / SMF2.

[0108] 9.10. BMSC-C / SMF2 sends an Nsmf_PDUSession_UpdateSMContext response to AMF2.

[0109] 9.11. SMF2 returns a session start Ack to NEF, including TMGI and optional (such as BMSC-U IP address and port number).

[0110] 9.12. The NEF sends a session start Ack to the AF, including the TMGI, optional (such as the BMSC-U IP address and port number). The AF then sends downlink traffic to the BMSC-U IP address and port number. The BMSC-U / UPF2 then generates the MBS downlink traffic (e.g., using an IP multicast address as the destination IP address) and forwards the downlink MBS traffic to the RAN node through each N3 tunnel.

[0111] 9.13. If the AF wants to modify the QoS information of the MBS session, it discovers the PCF2 serving the MBS session via the Binding Support Function (BSF) using an IP multicast address. The AF then provides the new application / service information to the PCF2.

[0112] 9.14. PCF2 initiates a PDU session modification process to modify the QoS information of the MBS session.

[0113] Example 4

[0114] Figure 10The illustration shows another example signaling sequence 1000 for establishing an MBS session according to this technology. In this example, BMSC-C and BMSC-U are deployed together. BMSC-C and BMSC-U can also be deployed in a distributed manner. Multiple SMFs and / or UPFs can serve the MBS session.

[0115] 10.1. The AF invokes a NEF service operation via an AF request. The content of this service operation (e.g., the AF request) includes the AF transaction ID, the requested S-NSSAI, the requested DNN, and the requested SSC mode. These parameters are used to establish an MBS session. This content also includes the TMGI, IP multicast address, and / or the target area serving the PDU session. The AF may also include AF subscription information to subscribe to events related to the PDU session, enabling the AF to receive corresponding notifications (AF notification report information).

[0116] 10.2. NEF authorization: Does it allow AF to start an MBS session? NEF converts the target area into a TAI list and forwards the session start to BMSC.

[0117] 10.3. The BMSC converts the target area into a TAI list. The BMSC discovers the corresponding AMF serving the TAI list via NRF. Instead of interacting with the SMF, the BMSC can send a session trigger message to each selected AMF2. This message includes the TMGI, the requested S-NSSAI, the requested DNN, the requested SSC pattern, and / or the target TAI list. The message may also include event subscription information, including the BMSC address and notification-related ID.

[0118] BMSC can select multiple AMF2s based on the TAI list. Operation 10.3 can be performed on each selected AMF2.

[0119] 10.4. After receiving a session trigger message from the BMSC, AMF2 creates an MBS session context associated with the TMGI. AMF2 discovers the SMF2 via NRF using selection parameters including a list of S-NSSAI, DNN, and / or TAI. AMF2 sends an Nsmf_PDUSession_CreateSMContext request to the selected SMF2. This message includes the TMGI, DNN, S-NSSAI, AMF ID, user location information, AF subscription information, etc. The user location may include a list of TAIs received from the BMSC.

[0120] 10.5. SMF2 creates an MBMS context associated with TMGI. Based on local configuration, SMF2 assigns a PDU session ID to the MBS session. SMF2 selects a UPF that supports the MBMS service. SMF2 establishes an N4 association with the selected UPF2. Shared N3 tunnel information is allocated by UPF2 and provided to SMF2. SMF2 can also assign IP addresses to the MBS session.

[0121] 10.6. SMF2 returns the Nsmf_PDUSession_CreateSMContext response. This message contains a reason value indicating whether the request was accepted. The message also includes the PDU session ID and SM context ID assigned by SMF2. AMF2 can use the SM context ID for subsequent messages to SMF2.

[0122] 10.7. If PCF2 is deployed, SMF2 can establish an association with PCF2, thus PCF2 can provide session-related policies to SMF2. SMF2 also sends the TMGI and IP multicast address of the MBS session to PCF2. SMF2 can also provide PCF2 with newly assigned IP addresses for the MBS session.

[0123] 10.8. SMF2 sends Namf_Communication_N1N2MessageTransfer to AMF2. This message includes parameters such as the PDU session ID and / or N2 SM information, such as PDU session ID, TMGI, QFI, QoS profile, UPF N3 tunnel information, S-NSSAI, etc. Because the MBS session is for a group of UEs rather than a single UE, SMF2 does not need to send an N1 message. After receiving the message, AMF2 sends a response to SMF2.

[0124] 10.9. AMF2 selects the RAN node list based on the TAI list. AMF sends an N2 PDU session request to each RAN node. This message carries the AMF NGAP UE ID, TMGI, and N2 SM information received from SMF2.

[0125] AMF can select multiple RAN nodes based on the TAI list. Operation 10.9 can be performed on each selected RAN node.

[0126] 10.10. The RAN creates an MBS session context associated with the TMGI and can reserve AN-specific resources for MBS services. The RAN can begin broadcasting the TMGI via the Uu interface. By obtaining the TMGI in the broadcast information, the UE determines whether it can access the RAN to receive the MBS services associated with that TMGI.

[0127] In some embodiments, the RAN may reserve AN-specific resources at a later stage. When no UE is interested in MBS services under this cell, the RAN does not need to allocate MBS resources for MBS services. When the RAN receives downlink packet data through the N3 tunnel, the RAN may discard these packet data because no radio resources have been reserved.

[0128] The RAN sends an N2 PDU session response to AMF2. This message includes the newly assigned RAN NGAP UE ID. AMF2 uses the RAN NGAP UE ID in subsequent N2 messages to the RAN to modify the MBS session. This message may also include parameters such as the PDU session ID, reason, N2 SM information (e.g., PDU session ID, N3 tunnel information, and the accepted / rejected QFI list), etc.

[0129] 10.11. For each RAN response, AMF2 sends an Nsmf_PDUSession_UpdateSMContext request to SMF2, which includes the SMF SM context ID and N2 SM information.

[0130] 10.12. For each request received from AMF2, SMF2 initiates an N4 session modification procedure to UPF2 to provide the N3 tunnel information received from the RAN node. UPF2 then associates each N3 tunnel information from the RAN node with the MBS session.

[0131] If multiple RANs are associated with an MBS session, the UPF2 replicates the MBS downlink traffic and forwards it to each RAN node via the corresponding N3 tunnel.

[0132] If UPF2 does not assign a UPF2 IP address and port number to the MBS session, then UPF2 will assign a UPF2 IP address and port number to the MBS session and provide it to SMF2.

[0133] 10.13. SMF2 sends an Nsmf_PDUSession_UpdateSMContext response to AMF2.

[0134] 10.14. Based on the subscription information received in Operation 10.4, the SMF2 sends a notification and a notification association ID to the BMSC. The notification message includes the TMGI and the UPF2 IP address and port number assigned to the MBS session. In some embodiments, the notification message may also include the IP address of the MBS session.

[0135] 10.15. If BMSC-U does not assign a BMSC-U IP address and port number to the MBS session, then BMSC-U will assign a BMSC-U IP address and / or port number to the MBS session. BMSC returns a session start Ack to NEF, including TMGI, BMSC-U IP address, and port number.

[0136] 10.16. The NEF sends a session start Ack to the AF, including the TMGI, BMSC-U IP address, and port number. The AF then sends downlink traffic to the BMSC-U IP address and port number. The BMSC-U generates downlink MBS traffic (using the IP multicast address as the destination IP address) and sends it to the UPF2 via an IP tunnel (the tunnel's destination address is the UPF2's IP address). If multiple MBS sessions have been established for the MBS service, the BMSC-U replicates the downlink MBS traffic to the corresponding UPF2 via different IPs in the IP tunnel. The UPF2 then removes the external tunnel header and replicates the downlink MBS traffic, forwarding it to each RAN node through the shared N3 tunnel associated with the MBS session.

[0137] BMSC can send session trigger messages to multiple AMFs in parallel, thus enabling the establishment of multiple MBS sessions. In this scenario, the RAN maintains only one MBS session context for each TMGI.

[0138] 10.17. If the AF / BMSC wants to modify the QoS information of MBS traffic, it discovers the PCF2 serving the MBS session via the BSF using the IP multicast address of the MBS session. The BSF can return multiple PCFs serving the MBS session. Alternatively, the BMSC can use the IP address of the MBS session to query the BSF to determine the PCF for modification for the MBS session. The BMSC then provides the new application / service information, along with the TMGI and / or IP multicast address, to the PCF2 for each MBS session.

[0139] 10.18.PCF2 initiates a PDU session modification procedure to modify the QoS information for each MBS session. If multiple MBS sessions are associated with TMGI and / or IP multicast addresses, operation 10.18 can be performed on each MBS session.

[0140] Example 5

[0141] Figure 11The illustration shows an example signaling sequence 1100 for configuring radio resources for an MBS session according to the present technology. When a session context is established, the RAN determines whether to use point-to-point (PTP) resources or point-to-multipoint (PTM) resources to send MBS downlink data to the UE. The RAN makes this decision based on the number of UEs in the same cell that are interested in MBS services. After a UE joins an MBS session, the UE can enter an idle state, and the UE context in the RAN is released. In order to receive MBS services, the UE needs to be in a connected state again, so that the RAN can create a UE context and determine whether the UE is authorized to receive MBS services.

[0142] 11.1.RAN receives MBS downlink data through the N3 tunnel of the MBS session.

[0143] 11.2 After the MBS session context has been established in the RAN, the RAN broadcasts the TMGI of the MBS service to multiple UEs.

[0144] 11.3. The UE obtains the TMGI via the broadcast channel. If the UE is interested in accessing the MBS service identified by the TMGI, and the unicast PDU session associated with the MBS service has not yet been activated, the UE initiates a service request procedure to activate the unicast PDU session associated with the MBS service.

[0145] 11.4. The RAN forwards the service request to AMF1. The service request message includes the PDU session ID that identifies the PDU session to be reactivated.

[0146] 11.5. Based on the PDU session ID, AMF1 determines SMF1 and sends an Nsmf_PDUSession_UpdateSMContext request to SMF1 to activate the PDU session.

[0147] 11.6.SMF1 returns the Nsmf_PDUSession_UpdateSMContext response. This response message includes the authorized TMGI in the N2 message container.

[0148] 11.7.AMF1 sends the N2 PDU session request along with the N2 message container to the RAN.

[0149] 11.8. If the RAN receives a TMGI from the network, the UE is authorized to receive MBS services. The RAN determines whether to use PTP resources (e.g., when the UE is connected) or PTM resources (e.g., when the UE is idle) to deliver MBS downlink traffic to the UE. The RAN can also make this decision based on the number of UEs in the same cell that are interested in the service.

[0150] 11.9. The RAN sends an RRC connection reconfiguration message to the UE to configure PTP or PTM resources for MBS services. The resource configuration is determined in part based on the service quality profile associated with the MBS session.

[0151] 11.10. The UE sends an RRC connection reconfiguration ACK to the RAN.

[0152] 11.11. If PTP resources are configured, the RAN transmits MBS downlink traffic to the UE via PTP resources. Alternatively, the RAN transmits MBS services to the UE via configured PTM resources. In some embodiments, the UE can release its RRC connection and enter an inactive state while still being able to receive MBS services via PTM resources.

[0153] Figure 12 An example of a wireless communication system 1200 is illustrated, in which techniques according to one or more embodiments of the present invention can be applied. The wireless communication system 1200 may include one or more base stations (BS) 1205a, 1205b, one or more wireless devices 1210a, 1210b, 1210c, 1210d, and a core network 1225. Base stations 1205a and 1205b may provide wireless services to wireless devices 1210a, 1210b, 1210c, and 1210d in one or more wireless sectors. In some embodiments, base stations 1205a and 1205b include directional antennas that generate two or more directional beams to provide wireless coverage in different sectors.

[0154] The core network 1225 can communicate with one or more base stations 1205a and 1205b. The core network 1225 provides connectivity with other wireless communication systems and wired communication systems. The core network may include one or more service subscription databases to store information related to subscribed wireless devices 1210a, 1210b, 1210c, and 1210d. The first base station 1205a can provide wireless services based on a first wireless access technology, while the second base station 1205b can provide wireless services based on a second wireless access technology. Depending on the deployment scenario, base stations 1205a and 1205b can be deployed together or installed separately in the field. Wireless devices 1210a, 1210b, 1210c, and 1210d can support a variety of different wireless access technologies. The technologies and embodiments described in this document can be implemented by base stations of the wireless devices described in this document.

[0155] Figure 13This is a block diagram representation of a portion of an applicable wireless station according to one or more embodiments of the present technology. The radio station 1305, such as a base station or wireless device (or UE), may include processor electronics 1310, such as a microprocessor implementing one or more wireless technologies presented herein. The radio station 1305 may include transceiver electronics 1315 for transmitting and / or receiving wireless signals via one or more communication interfaces (e.g., antenna 1320). The radio station 1305 may include additional communication interfaces for transmitting and receiving data. The radio station 1305 may include one or more memories (not explicitly shown) configured to store information such as data and / or instructions. In some embodiments, processor electronics 1310 may include at least a portion of transceiver electronics 1315. In some embodiments, the radio station 1305 is used to implement at least some of the disclosed technologies, modules, or functions. In some embodiments, the radio station 1305 may be configured to perform the methods described herein.

[0156] It should be understood that this document discloses techniques that can be implemented in various embodiments to establish and manage MBS sessions in various scenarios. The disclosed and other embodiments, modules, and functional operations described in this document can be implemented in digital electronic circuits, or in computer software, firmware, or hardware, including the structures disclosed herein and their structural equivalents, or in combinations thereof. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium for execution by or control of the operation of a data processing apparatus. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a combination of materials that implement machine-readable propagated signals, or a combination thereof. The term "data processing apparatus" includes all means, devices, and machines for processing data, including, for example, a programmable processor, a computer, or a plurality of processors or computers. In addition to hardware, the apparatus may include code that creates an execution environment for the computer program in question, for example, code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination thereof. The propagation signal is an artificially generated signal, such as a machine-generated electrical, optical, or electromagnetic signal, which is generated to encode information for transmission to a suitable receiver device.

[0157] Computer programs (also known as programs, software, software applications, scripts, or code) can be written in any programming language, including compiled or interpreted languages, and can be deployed in any form, including as standalone programs or as modules, components, subroutines, or other units suited to a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored as a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), as a single file dedicated to the program in question, or as multiple collaborative files (e.g., a file storing one or more modules, subroutines, or code sections). Computer programs can be deployed to execute on a single computer or on multiple computers located in one place or distributed across multiple locations and interconnected via a communication network.

[0158] The processes and logic flows described in this document can be executed by one or more programmable processors that execute one or more computer programs to perform functions by manipulating input data and generating output. The processes and logic flows can also be executed by dedicated logic circuits, and the devices can be implemented as dedicated logic circuits, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits).

[0159] For example, processors suitable for executing computer programs include general-purpose and special-purpose microprocessors, as well as any one or more processors in any kind of digital computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The basic components of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include, or be operatively coupled to, one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, to receive data from or transfer data to, or both. However, a computer does not need to have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROMs and DVD-ROMs. The processor and memory may be supplemented or incorporated therein by dedicated logic circuitry.

[0160] While this patent document contains numerous details, these details should not be construed as limiting any invention or the scope of the claims, but rather as descriptions of features characteristic of particular embodiments of a particular invention. Certain features described in the context of individual embodiments in this patent document may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, although features may be described above as functioning in certain combinations, and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and the claimed combination may be for sub-combinations or variations thereof.

[0161] Similarly, although operations are described in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order or sequence shown, or requiring all of the shown operations to obtain the desired result. Furthermore, the separation of various system components in the embodiments described in this patent document should not be construed as requiring such separation in all embodiments.

[0162] Only some implementation schemes and examples are described, and other implementations, enhancements and variations may be made based on what is described and shown in this patent document.

Claims

1. A wireless communication method, comprising: The Broadcast and Multicast Service Center receives a request to establish a multicast or broadcast session for an application function, wherein the request includes information representing a first target area of ​​the multicast or broadcast service associated with the multicast or broadcast session; The broadcast and multicast service center function determines at least one access and mobility management function based on the information; The broadcast and multicast service center function sends a session trigger message to the at least one access and mobility management function to allow the at least one access and mobility management function to initiate the establishment of the multicast or broadcast session; and The Broadcast and Multicast Service Center function receives a request from the application function to modify the multicast or broadcast session. The request to modify the multicast or broadcast session is based on a second target area of ​​the multicast or broadcast session, wherein the second target area is determined based on the location of one or more mobile devices authorized to access the multicast or broadcast service, and wherein the location of the one or more mobile devices is reported by the at least one access and mobility management function.

2. The method according to claim 1, wherein, The information representing the target area for the multicast or broadcast service includes a list of Tracking Area Identifiers (TAIs).

3. The method according to claim 1 or 2, wherein, The request also includes an identifier that identifies the multicast or broadcast service associated with the multicast or broadcast session.

4. The method according to any one of claims 1 to 3, wherein, The session trigger message includes an identifier that identifies the multicast or broadcast service and a first Internet Protocol (IP) address associated with the identifier.

5. A method for wireless communication, comprising: The access and mobility management function receives a session trigger message from the broadcast and multicast service center function to trigger the establishment of a multicast or broadcast session, wherein the session trigger message includes an identifier that identifies the multicast or broadcast service associated with the multicast or broadcast session, and wherein the session trigger message indicates a first target area of ​​the multicast or broadcast service associated with the multicast or broadcast session. The access and mobility management function sends a request to the session management function to establish the multicast or broadcast session; and The access and mobility management function reports the location of one or more mobile devices authorized to access the multicast or broadcast service, wherein a second target area of ​​the multicast or broadcast session is determined based on the location of the one or more mobile devices, and wherein a request is made to modify the multicast or broadcast session based on the second target area.

6. The method according to claim 5, wherein, The session trigger message includes an IP multicast address associated with an identifier that identifies the multicast or broadcast service.

7. The method according to claim 5 or 6, comprising: The access and mobility management function receives a response indicating the establishment of the multicast or broadcast session, wherein the response includes an identifier identifying the multicast or broadcast session allocated by the session management function for the multicast or broadcast service.

8. A method for wireless communication, comprising: The base station receives a message from a communication node in the core network, wherein the message includes an identifier that identifies a multicast or broadcast service that authorizes a mobile device to receive data; The base station receives a request from the communication node to establish a multicast or broadcast session for the multicast or broadcast service, wherein the request includes an identifier identifying the multicast or broadcast service and a service quality profile of the multicast or broadcast session; The base station sends a message to the mobile device authorized to receive data from the multicast or broadcast service. The message represents the resource configuration of the multicast or broadcast session, wherein the resource configuration is determined based on whether the mobile device is in a connected or idle state, such that a point-to-point resource configuration is used when the mobile device is in a connected state, and a point-to-multipoint configuration is used when the mobile device is in an idle state; and The base station uses resources configured according to the resource configuration to send data for the multicast or broadcast session.

9. The method according to claim 8, wherein, The resource configuration is also based on the quality profile associated with the multicast or broadcast session.

10. The method according to claim 8, wherein, When the mobile device is in the idle state, the base station releases the context of the mobile device, wherein the context includes the identifier that identifies a multicast or broadcast service that authorizes the mobile device to receive data.

11. The method according to any one of claims 8 to 10, wherein, The resource allocation is also determined based on the number of mobile devices interested in accessing the multicast or broadcast service.

12. A communication device comprising a processor configured to implement the method according to any one of claims 1 to 11.

13. A computer program product storing code that, when executed by a processor, causes the processor to implement the method according to any one of claims 1 to 11.

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