KR20220104603A - Method and apparatus for inteworking between 4g mbms and 5g mbs systems - Google Patents

Abstract

The present invention provides a method by which a UE supports interworking between different radio access technologies (RATs). The method comprises: receiving a MBS service notification from an AF or a MBSF; accessing and registering for a first RAT system based on the MBS service notification; receiving a multicast service through the first RAT system; reporting a UE status to the AF or an AS before the UE moves to a second RAT system; moving to the second RAT system; and modifying a PDU session or a PDN connection with the second RAT system and receiving a multicast service through the second RAT system as the second RAT system identifies a MBS service preparation completion notification from the AF or the AS. Therefore, the UE can receive the multicast service while moving between a 4G system and a 5G system.

Description

Method and apparatus for interworking between 5G MBS and 4G MBMS

The present disclosure relates to the field of a mobile communication system in which a terminal receiving a multicast service supports handover between 4G and 5G cellular networks, and to a method and apparatus for seamlessly providing a multicast service to a terminal.

Efforts are being made to develop an improved 5G communication system or pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, the 5G communication system or the pre-5G communication system is called a 4G network after (Beyond 4G Network) communication system or an LTE system after (Post LTE) system.

In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to alleviate the path loss of radio waves and increase the propagation distance of radio waves in the very high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beamforming, and large scale antenna technologies are being discussed.

In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway. In addition, in the 5G system, the advanced coding modulation (ACM) methods FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), and advanced access technologies FBMC (Filter Bank Multi Carrier), NOMA (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects and creates new values in human life can be provided. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, advanced medical service, etc. can be applied to

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, in technologies such as sensor network, machine to machine (M2M), and MTC (Machine Type Communication), 5G communication technology is implemented by techniques such as beam forming, MIMO, and array antenna. there will be The application of a cloud radio access network (cloud RAN) as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

As various services can be provided according to the above-mentioned and the development of wireless communication systems, a method for smoothly providing these services is required.

In order to transmit the same data to a plurality of terminals in a mobile communication network, it is necessary to provide a data service through multicast/broadcast. For example, a method of transmitting data through multicast/broadcast for a TV/audio service, a V2X service, or a massive CIoT (Consumer Internet of Things) service to a plurality of terminals in a specific area is required. .

Multicast/broadcast service is provided through MBMS (Multimedia Broadcast/Multicast Service) technology in the existing EPS (Evolved Packet System) network, and 5G MBS (Multicast-Broadcast Service) technology is provided in the 5GS network. Even when moving between the EPS network and the 5GS network, a method for continuously supporting the multicast service is needed.

According to an embodiment of the present disclosure, receiving an MBS service notification from AF or MBSF, accessing and registering with a first RAT system based on the MBS service notification, and receiving a multicast service through the first RAT system and, before the terminal moves to the second RAT system, reports a UE status to AF or AS, moves to the second RAT system, and prepares MBS service from the AF or AS in the second RAT system Upon identification of the completion notification, a terminal that modifies a PDU session or PDN connection with the second RAT system and receives a multicast service through the second RAT system interworking between different radio access technologies (RATs) ( Interworking) can be provided.

According to various embodiments of the present disclosure, there is provided a method for enabling a terminal that moves between a 5G system and a 4G system to continuously use a multicast service in each system, thereby providing a multicast service smoothly even while the terminal is moving between 4G and 5G It becomes possible to receive

1 is an exemplary diagram for explaining the structure of a 4G and 5G cellular system for providing a multicast service according to an embodiment of the present disclosure.
2 is a diagram for explaining a process in which a terminal is switched to shared transmission according to an embodiment of the present disclosure.
3 is an exemplary diagram for a procedure for setting a multicast session and group to initiate a multicast service in a 5G system according to an embodiment of the present disclosure.
4 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.
5 is a diagram for explaining initiation of a multicast service according to an embodiment of the present disclosure.
6 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.
7 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.
8 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.
9 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.
10 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.
11 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.
12 is a diagram for describing a terminal according to an exemplary embodiment of the present disclosure.
13 is a diagram for describing a network device according to an exemplary embodiment of the present disclosure.

Hereinafter, the operating principle of the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Hereinafter, when it is determined that a detailed description of a known function or configuration related to the embodiments of the present disclosure may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of functions in the present disclosure, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

A term for identifying an access node used in the following description, a term referring to network entities, a term referring to messages, a term referring to an interface between network objects, a term referring to various identification information and the like are exemplified for convenience of description. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

For convenience of description, the present disclosure uses terms and names defined in standards TS 23.401, TS 23.501, TS 23.502, and TS 23.503 for 4G and 5G systems. However, the present disclosure is not limited by the above terms and names. Accordingly, the terms or names defined in the present disclosure may be equally applied to systems based on other standards.

In the present disclosure, the MBMS system, which is a multicast and broadcast system of the 4G system, the 4G multicast system, and the 4G MBMS system are used interchangeably with the same meaning.

In the present disclosure, a 5MBS system, a 5G multicast system, and a 5G MBS system, which are multicast and broadcast systems of a 5G system, are used interchangeably to describe the same.

In addition, although the present disclosure is described based on a multicast service, it is apparent to those skilled in the art that the present disclosure can also be applied to a broadcast service.

1 is an exemplary diagram for explaining the structure of a cellular system for an MBS service according to an embodiment of the present disclosure. 1 shows, for example, the structure of a 4G-5G interworking system.

Referring to FIG. 1 , a cellular system includes user equipment (UE), NG Radio Access Network (NG-RAN), Evolved UMTS Terrestrial Radio Access Network (E-UTRAN), Multi-cell/multicast Coordination Entity (MCE), and AMF ( Access and Mobility Management Function), MB-UPF (Multicast/Broadcast User Plane Function), MB-SMF (Multicast/Broadcast-Session Management Function), PCF (Policy Control Function), SMF (Session Management Function), UPF (User Plane) Function), MME (Mobility Management Entity), SGW, MBMS-GW, PGW-C, PGW-U, NEF (Network Exposure Function), BMSC, MBSF-C (Multicast/Broadcast Service Function ? Control plane), MBSF-U (Multicast/Broadcast Service Function - User plane), AF (Application Function), AS (Application Server), UDR (User Data Repository), and AUSF (Authentication Server Function) may be included.

In order to continuously support the multicast service in the existing 5G system and the 4G system, a cellular system for the multicast service may be configured with the following network functions and services.

AF / AS, for example, V2X application server, CIoT application server, MCPTT (Mission Critical Push To Talk) application, content provider (Contents provider), TV or audio service provider, streaming video service provider, etc. It can be implemented. In this case, AS and AF may be used with the same meaning, but it may be preferable to describe AS when related to user data or 4G system, and it may be preferable to describe as AF when related to 5G control data (control plane).

When an AF/AS requests a multicast service, it receives media from MBSF-C, a network function that manages the multicast service session and controls traffic in the 5G system, and the AS (or content provider) to control the MBSF-C. MBSF-U, which is a multicast service media anchor in 5GS that processes media traffic based on it, receives a multicast service request from AF. In the 4G system, the BMSC for performing the same function may receive a multicast service request from the AS.

As above, when different entities receive the multicast service request of AF/AS, smooth interworking between the 4G system and the 5G system cannot be supported, so as shown in FIG. 1 , BMSC, MBSF-C, and MBSF- U may consist of one entity. In addition, it is assumed that other entities having similar functions between the 4G system and the 5G system are configured as one entity. For example, UPF and PGW-U may be configured as one entity, SMF and PGW-C may be configured as one entity, and HSS and UDM may be configured as one entity. It can be supported through an interface.

MBSF may provide a service level function for supporting MBS while interworking with AF and MB-SMF. In addition, the MBSF may select an appropriate MB-SMF, allocate a multicast session ID or a multicast group ID for a multicast service, and the like.

MB-SMF is an entity that manages multicast sessions for multicast services. MB-SMF may control the transmission of multicast data from MB-UPF to RAN.

The MB-UPF may directly receive multicast data from the AS, or may receive multicast data from the MBSF-U. In addition, MB-UPF may deliver multicast data to RAN node or UPF based on QoS.

2 is a diagram for explaining a process in which a terminal is switched to shared transmission according to an embodiment of the present disclosure.

Specifically, FIG. 2 shows that a terminal receiving a multicast/broadcast service in 5G switches to individual delivery, moves to a 4G system to receive a multicast service, and starts the same multicast/broadcast service in the 4G system. In one case, it is a process in which the terminal switches to shared transmission (eMBMS delivery).

In step 1, the AF may request the multicast service through the NEF MBSF (or NEF, see FIG. 3 for a detailed description through the NEF) for the multicast service. Accordingly, setting for a multicast service may be performed in the cellular network. In this process, the MBSF may select an appropriate MB-SMF, request an MBS session from the selected MB-SMF (1a), and prepare MBS data transmission for the multicast service. Step 1 is a multicast group setting process, and this process will be described in more detail with reference to FIG. 3 .

In step 2, the AF or MBSF may notify the UE of information about the multicast service through MBS service announcement according to the decision in step 1. The MBS service announcement message may include a multicast group ID or multicast session ID for a corresponding service, for example, TMGI or an IP address of a multicast service source. In addition, the MBS service announcement message may include information on the RAT to which the corresponding multicast service is serviced, for example, NR only or E-UTRAN only or both NR and E-UTRAN. In another embodiment of the present disclosure, the MBS service announcement message may include the ID of the PLMN serviced by the corresponding multicast service or the PLMN ID + NID of the SNPN. In this case, information of a system in which the corresponding multicast service is serviced may include, for example, MBMS only, 5MBS only, or both MBMS and 5MBS.

In step 3, the terminal can access & register with the 5G network and create a PDU session.

In step 4, the UE makes a join request for a specific multicast service, for example, TMGI through a PDU session modification or PDU session establishment process. That is, the terminal includes a list of TMGIs or TMGIs that the terminal intends to join to a PDU session modification request message, a PDU session establishment request message, or a session management (SM) non-access stratum (NAS) message through AMF through PGW-C. + Can be forwarded to SMF.

In step 4a, when there is no MBS session context for the corresponding TMGI, the PGW-C + SMF receiving the join request from the terminal may request the MB-SMF to receive the corresponding information.

In step 5, the serving NG-RAN node may recognize a situation in which handover is required, and inform the AMF.

In step 6, the AMF may acquire a PDU session context through PGW-C + SMF in order to prepare for handover to the 4G network. In this process, if there is no MBS session context or the PDU session is associated with shared delivery, the PGW-C + SMF may be obtained through MB-SMF.

In step 7, the PGW-C + SMF may trigger a transition from shared delivery to individual delivery as a transmission method to the NG-RAN. In addition, in order to prepare for switching to shared delivery again later, the MBS session context may be maintained separately.

In another embodiment of the present disclosure, the MB-SMF receiving the request in step 6 determines to switch the transmission method to the NG-RAN from shared delivery to individual delivery, and informs PGW-C + SMF to the NG-RAN. It is possible to trigger the transition from shared delivery to individual delivery in the transmission method of .

In step 7a, the PGW-C+SMF may transmit signaling to the NG-RAN through the AMF in order to switch the terminal's transmission method to the NG-RAN to individual delivery. Step 7 and step 7a may be performed together with step 6 and other signaling such as handover ready or handover command message.

Upon receiving the Handover command message in step 8, the NG-RAN may perform handover to the 4G network.

In step 9, the terminal is receiving a multicast service through individual delivery in the 4G network. The fact that the MBMS service is started for the same multicast service in the 4G network can be recognized based on the received TMGI information, etc. through the reception of a service announcement message in the 4G network.

In step 10, upon recognizing TMGI information, etc., the UE may decide to receive a multicast service through MBMS delivery.

In step 11 and step 12, in order to release the previously maintained resources for individual delivery, the UE may transmit the TMGI information and the individual delivery cancellation request message to the PGW-C+SMF through the PCO of PDN connection modification.

In step 13, the PGW-C+SMF receiving the request cancels the DL tunnel for individual delivery corresponding to the TMGI. For example, an operation such as erasing the corresponding DL packet filter is performed together with the PGW-U+UPF, and updated tunnel information is transmitted to the E-UTRAN (step 13). If there are no more terminals consuming the multicast session corresponding to the TMGI in the PGW-C+SMF, the multicast session context for the TMGI may be deleted.

3 is a diagram for explaining a procedure for setting a multicast session and a group to initiate a multicast service in a 5G system according to an embodiment of the present disclosure.

In step 1, the AF requests a multicast session from the NEF or MBSF for the multicast service. The request message may include information on a corresponding multicast service, for example, an ID of a multicast group using a multicast service, an MBS session ID, or a TMGI. In another embodiment, the request message may also include a QoS request for a multicast service.

In step 2, the NEF or MBSF receiving the request may perform a permission check on whether to service the multicast session. In this case, if the service is allowed, the NEF or MBSF receiving the request may select an MB-SMF to manage the multicast session.

In step 3, the ID of the selected MB-SMF may be stored in the UDR. That is, the NEF or MBSF may transmit and store the address information of the MB-SMF ID or the MB-SMF ID together with the ID of the multicast group using the multicast service, the MBS session ID, or the TMGI to the UDR.

In step 4, the NEF or MBSF may send a multicast distribution session request message to the selected MB-SMF. That is, the NEF or MBSF may request a transmission session for multicast data transmission for the multicast group ID, MBS session ID, or TMGI. The multicast distribution session request message may include an ID of a multicast group, an MBS session ID, or a TMGI.

In step 5, the MB-SMF receiving the request may send an MBS policy association request message to the PCF.

In step 6, for binding with the PCF serving the ID of the multicast group, the MBS session ID, or the TMGI, the PCF may register the binding information in the BSF together with the PCF ID.

In step 7, the PCF may obtain information on the ID of the multicast group, the MBS session ID, or the TMGI from the UDR.

In step 8, the PCF may determine the policy information based on the information received from the UDR and transmit it to the MB-SMF.

In steps 9 and 10, the MB-SMF may configure a tunnel to be used for data traffic transmission for the MBS session through signaling with the MB-UPF.

In steps 11 and 12, a response to a multicast distribution session request and a response to a multicast session may be sent to the NEF or MBSF and AF, respectively.

4 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.

Specifically, FIG. 4 shows multicast service subscription information and 5MBS function support of the terminal provided by the MME when the terminal receiving the multicast service in 4G moves to the 5G system and the same multicast service as in the 4G system is not started. This is a process for preemptively starting the same multicast service in the 5G system based on whether or not there is.

In step 1, the AS may request the BMSC to establish an MBMS session for multicast service in the 4G system.

In step 2, the AS or BMSC may deliver a service announcement message to the UE.

In step 3a, the terminal may perform attach to the 4G system. In this case, the UE may inform the MME whether there is 5MBS capability or supports 5MBS feature.

In step 3b, the terminal may receive the multicast service according to the TMGI corresponding to the desired multicast service.

In step 4, the MME can know the multicast service information to which the terminal is subscribed from the TMGI list from the subscription information for the accessing terminal received from the HSS in step 3a.

In step 5, the MME is mapped to the multicast service to which the terminal is subscribed together with an indicator indicating that the terminal supports 5MBS capability or 5MBS feature so that the multicast service received by the accessed terminal can be prepared even in the 5G system. The list of TGMI and ID information of the UE (eg, status report including information such as IMSI or MSISDN) may be notified to BMSC+MBSF through MBMS-GW.

In step 6a, based on the status report received from the terminal, the BMSC+MBSF (or AF/AS) may determine to start a specific multicast service even in the 5G system. For example, when the BMSC+MBSF determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the BMSC+MBSF initiates a multicast service corresponding to the TMGI. can decide to Accordingly, as in steps 8b and 8c, the multicast group setting process can be performed through signaling with the MB-SMF.

In step 7, when the AF/AS determines whether to start the service, the BMSC+MBSF may forward a status report message to the AF/AS.

In step 6b, when the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the AF/AS may determine to start a multicast service corresponding to the corresponding TMGI. Accordingly, as in steps 8a, 8b, and 8c, the multicast group establishment process may be performed through signaling between MB-SMF and BMSC+MBSF. The multicast group setting process may be performed as described in FIG. 2A.

In step 9, when the multicast group configuration for a specific TMGI is finished, the AF/AS may notify the UE that the multicast service corresponding to the TMGI is supported even in the 5G network through a service announcement message or the like.

When the terminal moves to the 5G network as in step 10, for continuous service level interworking, in step 11, the terminal may perform UE joining for TMGIs for the multicast service being serviced. For example, the UE may request a join for a specific multicast service (eg, TMGI) through a PDU session modification or PDU session establishment process. That is, the terminal includes a list of TMGIs or TMGIs that the terminal intends to join to a PDU session modification request message, a PDU session establishment request message, or a session management (SM) non-access stratum (NAS) message through AMF through PGW-C + Can be forwarded to SMF.

5 is a diagram for explaining initiation of a multicast service according to an embodiment of the present disclosure.

Specifically, FIG. 5 shows the terminal's multicast service information and 5MBS function provided by the terminal to the PGW when the terminal receiving the multicast service in 4G moves to the 5G system and the same multicast service as in the 4G system is not started. It is a process of preemptively starting the same multicast service in the 5G system based on whether it is supported or not.

In step 1, the AS may request the BMSC to establish an MBMS session for multicast service in the 4G system.

In step 2, the AS or BMSC may deliver a service announcement message to the UE.

In step 3a, the terminal may perform attach to the 4G system. In this case, the UE may inform the PGW-C+SMF of whether the UE has 5MBS capability or supports the 5MBS feature and the TMGI list for the multicast service to be serviced by the UE through the PCO.

In step 3b, the terminal may receive the multicast service according to the TMGI corresponding to the desired multicast service.

In step 4, if the terminal does not send the TMGI list for the multicast service to be serviced in step 3a or there is an update, the terminal transmits the TMGI list information the terminal is receiving through the PCO of the PDN connection modification request message to the PGW -C+SMF can be sent.

In step 5, the PGW-C + SMF is a multicast service to which the terminal is subscribed together with an indicator indicating that the terminal supports the 5MBS capability or 5MBS feature so that the multicast service received by the connected terminal can be prepared even in the 5G system. The list of TGMI mapped to the cast service and ID information of the UE (eg, status report including information such as IMSI or MSISDN) may be notified to BMSC+MBSF through MBMS-GW.

In step 6a, based on the status report received from the terminal, it may be determined that the BMSC+MBSF (or AF/AS) can initiate a specific multicast service even for the 5G system. For example, when the BMSC+MBSF determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the BMSC+MBSF initiates a multicast service corresponding to the TMGI. decide to do Accordingly, as in steps 8b and 8c, the multicast group setting process can be performed through signaling with the MB-SMF.

In step 7, when the AF/AS determines whether to start the service, the BMSC+MBSF may forward a status report message to the AF/AS.

In step 6b, when the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the AF/AS may determine to start a multicast service corresponding to the corresponding TMGI. Accordingly, as in steps 8a, 8b, and 8c, the multicast group establishment process may be performed through signaling between MB-SMF and BMSC+MBSF. The multicast group setting process may be performed as described in FIG. 3 .

In step 9, when the multicast group configuration for a specific TMGI is finished, the AF/AS may notify the UE that the multicast service corresponding to the TMGI is supported even in the 5G network through a service announcement message or the like.

When the terminal moves to the 5G network as in step 10, for continuous service level interworking, in step 11, the terminal may perform UE joining for TMGIs for the multicast service being serviced.

6 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.

Specifically, FIG. 6 shows the terminal's multicast service information and 5MBS function provided by the terminal to the application server when the terminal that was receiving the multicast service in 4G moves to the 5G system and the same multicast service as in the 4G system is not started. It is a process of preemptively starting the same multicast service in the 5G system based on support or the like.

In step 1, the AS may request the BMSC to establish an MBMS session for multicast service in the 4G system.

In step 2, the AS or BMSC may deliver a service announcement message to the UE.

In step 3a, the terminal may perform attach to the 4G system. At this time, the UE may inform the PGW-C+SMF of whether the UE has 5MBS capability or supports the 5MBS feature and the TMGI list for the multicast service to be serviced by the UE through the PCO.

In step 3b, the terminal may receive the multicast service according to the TMGI corresponding to the desired multicast service.

In step 4, the terminal is mapped to the multicast service to which the terminal is subscribed together with an indicator indicating that the terminal supports the 5MBS capability or 5MBS feature so that the multicast service received by the connected terminal can be prepared in the 5G system. The list of TGMI and ID information of the terminal (eg, status report including information such as IMSI or MSISDN) may be notified to BMSC+MBSF or AF/AS.

In step 5, based on the status report received from the terminal, the BMSC+MBSF or AF/AS may determine to start a specific multicast service even for the 5G system. For example, when the AF/AS determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the AF/AS provides a multicast service corresponding to the corresponding TMGI. You can decide to start. Accordingly, as in steps 6a, 6b, and 6c, the multicast group establishment process may be performed through signaling between MB-SMF and BMSC+MBSF. The detailed multicast group setting process may be performed as described in FIG. 3 .

In another embodiment of the present disclosure, when the BMSC+MBSF determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the BMSC+MBSF corresponds to the TMGI. It may decide to initiate a multicast service. Accordingly, as in steps 6b and 6c, the multicast group setting process can be performed through signaling with the MB-SMF.

In step 7, when the multicast group configuration for a specific TMGI is finished, the AF/AS may notify the UE that the multicast service corresponding to the TMGI is supported even in the 5G network through a service announcement message or the like.

As in step 8, the terminal moves to the 5G network and for continuous service level interworking, in step 9, the terminal can perform UE joining for TMGIs for the multicast service being serviced.

7 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.

Specifically, FIG. 7 shows the multicast service information of the terminal provided by the terminal to the application server when the same multicast service as in the 4G system is not started in the 5G system before the terminal receiving the multicast service in 4G moves to the 5G system. It is a process of preemptively starting the same multicast service in the 5G system based on a notification of movement to 5MBS.

In step 1, the AS may request the BMSC to establish an MBMS session for multicast service in the 4G system.

In step 2, the AS or BMSC may deliver a service announcement message to the UE.

In step 3a, the terminal may perform attach to the 4G system. At this time, the UE may inform the PGW-C+SMF of whether the UE has 5MBS capability or supports the 5MBS feature and the TMGI list for the multicast service to be serviced by the UE through the PCO.

In step 3b, the terminal may receive the multicast service according to the TMGI corresponding to the desired multicast service.

When the terminal moves to the 5G network as in step 4a, in step 4b, the terminal joins with an indicator indicating that the terminal will move to the 5G network so that the multicast service received by the access terminal can be prepared for the 5G system as well. The list of TGMI mapped to the multicast service and ID information of the UE (eg, status report including information such as IMSI or MSISDN) can be notified to BMSC+MBSF or AF/AS.

In step 5, based on the status report received from the terminal, the BMSC+MBSF or AF/AS may determine to start a specific multicast service even for the 5G system. For example, when the AF/AS determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the AF/AS starts the multicast service corresponding to the TMGI. can decide to Accordingly, as in steps 6a, 6b, and 6c, the multicast group establishment process can be performed through signaling between MB-SMF and BMSC+MBSF. The detailed multicast group setting process may be performed as described in FIG. 3 .

In another embodiment of the present disclosure, when the BMSC+MBSF determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the BMSC+MBSF corresponds to the TMGI. It may decide to initiate a multicast service. Accordingly, as in steps 6b and 6c, the multicast group setting process can be performed through signaling with the MB-SMF.

In step 7, when the multicast group configuration for a specific TMGI is finished, the AF/AS may notify the UE that the multicast service corresponding to the TMGI is supported even in the 5G network through a service announcement message or the like.

When the terminal moves to the 5G network as in step 8, for continuous service level interworking, in step 9, the terminal may perform UE joining for TMGIs for the multicast service being serviced.

8 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.

Specifically, FIG. 8 shows the multicast service subscription information and 5MBS function support of the terminal provided by the MME when the terminal receiving the multicast service in 4G moves to the 5G system and the same multicast service as the 4G system is not started. It is a process of preemptively starting the same multicast service to the 5G system based on whether or not

In step 1, AF / AS can establish a 5MBS session for multicast service in the 5G system based on the multicast group establishment process through signaling (1a, 1b, and 1c) between MB-SMF and BMSC+MBSF. . The detailed multicast group setting process may be performed as described in FIG. 2A .

In step 2, AF or MBSF may deliver a service announcement message to the UE.

In step 3a, the terminal may perform registration in the 5G system. In this case, the UE may inform the AMF whether there is MBMS capability or supports MBMS feature.

In step 3b, the terminal may receive the multicast service according to the TMGI corresponding to the desired multicast service.

In step 4, in step 3a, the MME can know the multicast service information to which the terminal is subscribed from the TMGI list from the subscription information for the access terminal received from the UDM.

In step 5, the AMF is mapped to the multicast service to which the terminal is subscribed together with an indicator indicating that the terminal supports the MBMS capability or MBMS feature so that the multicast service received by the connected terminal can be prepared even in the 4G system. The list of TGMI and ID information of the terminal (eg, status report including information such as IMSI or MSISDN) may be notified to BMSC+MBSF. In this case, the status report may be transmitted to BMSC+MBSF through MB-SMF or SMF by AMF.

In step 6a, based on the status report received from the terminal, it may be determined that the BMSC+MBSF can start a specific multicast service even for the 4G system. For example, when the BMSC+MBSF determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the BMSC+MBSF initiates a multicast service corresponding to the TMGI. can decide to Accordingly, as in step 8, the multicast group setting process can be performed through signaling (8a) with the MBMS-GW.

In another embodiment of the present disclosure, when the AF/AS determines whether to start the service, in step 7, the BMSC+MBSF may forward a status report message to the AF/AS.

In step 6b, when the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the AF/AS may determine to start a multicast service corresponding to the corresponding TMGI. Accordingly, as in step 8, the multicast group setting process can be performed through signaling (8a) between the MBMS-GW and the BMSC+MBSF.

In step 9, when the multicast group configuration for a specific TMGI is finished, the AF/AS may notify the UE that the multicast service corresponding to the TMGI is supported even in the 4G network through a service announcement message or the like.

When the terminal moves to the 4G network as in step 10, for continuous interworking at the service level level, in step 11, the terminal may receive services for TMGIs for the multicast service being serviced.

9 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.

Specifically, FIG. 9 shows the multicast service information provided by the terminal to the SMF and whether or not the MBMS function is supported, etc. This is a process for preemptively starting the same multicast service in the 4G system based on the

In step 1, AF / AS can establish a 5MBS session for multicast service in the 5G system based on the multicast group establishment process through signaling (1a, 1b, and 1c) between MB-SMF and BMSC + MBSF. . The detailed multicast group setting process may be performed as described with reference to FIG. 2A .

In step 2, AF or MBSF may deliver a service announcement message to the UE.

In step 3a, the terminal may perform registration in the 5G system.

In step 3b, the UE may send a TMGI list for a multicast service to be serviced by the UE through a PDU session establishment or PDU session modification request message and request UE joining. In this case, the UE transmits whether there is MBMS capability or supports MBMS feature to PGW-C+SMF, and the information may also be forwarded to MB-SMF.

In step 4 and step 5, the PGW-C+SMF or MB-SMF is an indicator indicating that the terminal supports MBMS capability or MBMS feature in order to enable the multicast service received by the accessed terminal to be prepared even in the 4G system. BMSC+MBSF can be notified through a list of TGMI mapped to the multicast service to which the UE is subscribed and ID information of the UE (eg, a status report including information such as IMSI or MSISDN).

In step 6a, based on the status report, the BMSC+MBSF may determine to start a specific multicast service even for the 4G system. For example, when the BMSC+MBSF determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the BMSC+MBSF initiates a multicast service corresponding to the TMGI. can decide to Accordingly, as in step 8, the multicast group setting process may be performed through signaling (8a) between the MBMS-GW and the MME and the E-UTRAN/MCE.

In another embodiment of the present disclosure, when the AF/AS determines whether to start the service, in step 7, the BMSC+MBSF may forward a status report message to the AF/AS.

In step 6b, when the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the AF/AS may determine to start a multicast service corresponding to the corresponding TMGI. Accordingly, as in step 8, the multicast group establishment process can be performed through signaling (8a) between MBMS-GW and MME, E-UTRAN/MCE, and BMSC+MBSF.

In step 9, when the multicast group configuration for a specific TMGI is finished, the AF/AS may notify the UE that the multicast service corresponding to the TMGI is supported even in the 4G network through a service announcement message or the like.

When the terminal moves to the 4G network as in step 10, for continuous interworking at the service level, in step 11, the terminal may receive a service for TMGIs for the multicast service being serviced.

10 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.

Specifically, FIG. 10 shows the multicast service information and MBMS function support of the terminal provided by the terminal to the application server when the terminal that was receiving the multicast service in 5G moves to the 4G system and the same multicast service as the 5G system is not started. This is a process for preemptively starting the same multicast service in the 4G system based on whether or not there is.

In step 1, AF / AS can establish a 5MBS session for multicast service in the 5G system based on the multicast group establishment process through signaling (1a, 1b, and 1c) between MB-SMF and BMSC + MBSF. . The detailed multicast group setting process may be performed as described with reference to FIG. 3 .

In step 2, AF or MBSF may deliver a service announcement message to the UE.

In step 3a, the terminal may perform registration in the 5G system.

In step 3b, the UE may send a TMGI list for a multicast service to be serviced by the UE through a PDU session establishment or PDU session modification request message and request UE joining.

In step 4, the terminal is mapped to the multicast service to which the terminal is subscribed together with an indicator indicating that the terminal supports the MBMS capability or MBMS feature so that the multicast service received by the connected terminal can be prepared even in the 4G system. The list of TGMI and ID information of the terminal (eg, status report including information such as IMSI or MSISDN) may be notified to BMSC+MBSF or AF/AS.

Based on the status report received from the terminal in step 5, the AF/AS may determine to start a specific multicast service even for the 4G system. For example, when the AF/AS determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the AF/AS provides a multicast service corresponding to the corresponding TMGI. You can decide to start. Accordingly, as in step 6, the multicast group establishment process may be performed through signaling (6a) between MBMS-GW and MME, E-UTRAN/MCE, and BMSC+MBSF.

In another embodiment of the present disclosure, when the BMSC+MBSF determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the BMSC+MBSF corresponds to the TMGI. It may decide to initiate a multicast service. Accordingly, as in step 6, the multicast group setting process may be performed through signaling (6a) between the MBMS-GW and the MME and the E-UTRAN/MCE.

In step 7, after setting the multicast group for a specific TMGI, the AF/AS may notify the UE that the multicast service corresponding to the TMGI is supported even in the 4G network through a service announcement message or the like.

When the terminal moves to the 4G network as in step 8, for continuous interworking at the service level, in step 9, the terminal may receive a service for TMGIs for the multicast service being serviced.

11 is a diagram for explaining initiating a multicast service according to an embodiment of the present disclosure.

Specifically, FIG. 11 shows the multicast service information and MBMS of the terminal provided by the terminal to the application server when the same multicast service as in the 4G system is not started before the terminal receiving the multicast service in 5G moves to the 4G system. This is a process for preemptively starting the same multicast service in the 4G system based on a notification of movement to a mobile station.

In step 1, the AF/AS may establish a 5MBS session for a multicast service in the 5G system through a multicast group establishment process through signaling between MB-SMF and BMSC+MBSF. The detailed multicast group setting process may be performed as described in FIG. 3 .

In step 2, AF or MBSF may deliver a service announcement message to the UE.

In step 3a, the terminal may perform registration in the 5G system.

In step 3b, the UE may send a TMGI list for a multicast service to be serviced by the UE through a PDU session establishment or PDU session modification request message and request UE joining.

When the terminal moves to the 4G network as in step 4a, the terminal joins with an indicator indicating that the terminal will move to the 4G network so that the multicast service received by the access terminal can be prepared in the 4G system in step 4b The list of TGMI mapped to the multicast service and ID information of the UE (eg, status report including information such as IMSI or MSISDN) can be notified to BMSC+MBSF or AF/AS.

In step 5, based on the status report received from the terminal, the AF/AS may determine to start a specific multicast service for the 4G system as well. For example, when the AF/AS determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the AF/AS provides a multicast service corresponding to the corresponding TMGI. You can decide to start. Accordingly, as in step 6, the multicast group establishment process may be performed through signaling (6a) between MBMS-GW and MME, E-UTRAN/MCE, and BMSC+MBSF.

In another embodiment of the present disclosure, when the BMSC+MBSF determines whether to start the service and the number of terminals for a specific TMGI exceeds a certain threshold based on the status report sent by the terminals, the BMSC+MBSF is the multi-function corresponding to the TMGI. It may decide to initiate a cast service. Accordingly, as in step 6, the multicast group setting process can be performed through signaling with the MB-SMF.

In step 7, after setting the multicast group for a specific TMGI, the AF/AS may notify the UE that the multicast service corresponding to the TMGI is supported even in the 4G network through a service announcement message or the like.

When the terminal moves to the 4G network as in step 8, for continuous interworking at the service level, in step 9, the terminal may receive a service for TMGIs for the multicast service being serviced.

12 is a diagram for describing a terminal according to an exemplary embodiment of the present disclosure.

The terminal 1200 may include a processor 1210 , a communication unit 1220 , and a memory 1230 . However, since not all of the illustrated components are essential, the terminal 1200 may be implemented with more or fewer components than those illustrated. In addition, the processor 1210 , the communication unit 1220 , and the memory 1230 may be implemented as a single chip in some cases. The terminal 1200 may correspond to the user equipment 400 shown in FIG. 4 .

Processor 1210 may include one or more processors or other processing devices that control the disclosed functions, processes, and/or methods. The operation of the terminal 1200 may be implemented by the processor 1210 .

The communication unit 1220 may include an RF transmitter for up-converting and amplifying the transmitted signal, and an RF receiver for down-converting the frequency of the received signal. However, according to another embodiment, the communication unit 1220 may be implemented with more or fewer components than shown.

The communication unit 1220 may be connected to the processor 1210 to transmit and/or receive signals. The signal may include control information and data. Also, the communication unit 1220 may receive a signal through a wireless channel and output it to the processor 1210 . The communication unit 1220 may transmit a signal output from the processor 1210 through a wireless channel.

The memory 1230 may store control information or data included in the signal acquired by the terminal 1200 . Memory 1230 may be coupled to processor 1210 and may store at least one instruction or protocol or parameter for the disclosed functions, processes and/or methods. Memory 1230 may include read-only memory (ROM) and/or random access memory (RAM) and/or a hard disk and/or CD-ROM and/or DVD and/or other storage device.

13 is a diagram for describing a network device according to an exemplary embodiment of the present disclosure.

The network device 1300 may include a processor 1310 , a communication unit 1320 , and a memory 1330 . However, not all of the illustrated components are essential, so the network device 1300 may be implemented with more or fewer components than those illustrated. In addition, the processor 1310 , the communication unit 1320 , and the memory 1330 may be implemented as a single chip in some cases.

Processor 1310 may include one or more processors or other processing devices that control the disclosed functions, processes, and/or methods. The operation of the network device 1300 may be implemented by the processor 1310 .

The communication unit 1320 may include an RF transmitter for up-converting and amplifying the transmitted signal, and an RF receiver for down-converting the frequency of the received signal. However, according to another embodiment, the communication unit 1320 may be implemented with more or fewer components than shown.

The communication unit 1320 may be connected to the processor 1310 to transmit and/or receive signals. The signal may include control information and data. Also, the communication unit 1320 may receive a signal through a wireless channel and output it to the processor 1310 . The communication unit 1320 may transmit a signal output from the processor 1310 through a wireless channel.

The memory 1330 may store control information or data included in a signal acquired by the network device 1300 . Memory 1330 may be coupled to processor 1310 and may store at least one instruction or protocol or parameter for the disclosed functions, processes and/or methods. Memory 1330 may include read-only memory (ROM) and/or random access memory (RAM) and/or a hard disk and/or CD-ROM and/or DVD and/or other storage device.

Methods according to the embodiments described in the claims or specifications of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer-readable storage medium or computer program product storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium or computer program product are configured for execution by one or more processors in the electronic device 600 (device). The one or more programs include instructions that cause the electronic device 600 to execute methods according to embodiments described in a claim or specification of the present disclosure.

Such programs (software modules, software) include random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable ROM (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or any other form of It may be stored in an optical storage device or a magnetic cassette. Alternatively, it may be stored in a memory composed of a combination of some or all thereof. In addition, each configuration memory may be included in plurality.

In addition, the program accesses through a communication network composed of a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. It may be stored in an attachable storage device that can be accessed. Such a storage device may be connected to a device implementing an embodiment of the present disclosure through an external port. In addition, a separate storage device on the communication network may be connected to the device implementing the embodiment of the present disclosure.

In the present disclosure, the term "computer program product" or "computer readable medium" refers to a medium such as a memory, a hard disk installed in a hard disk drive, and a signal as a whole. used for These "computer program products" or "computer-readable recording medium" are software configured with instructions for setting the length of a timer for receiving a missed data packet based on a network metric corresponding to the determined event according to the present disclosure. It is a means of providing a computer system.

In the specific embodiments of the present disclosure described above, elements included in the present disclosure are expressed in the singular or plural according to the specific embodiments presented. However, the singular or plural expression is appropriately selected for the context presented for convenience of description, and the present disclosure is not limited to the singular or plural component, and even if the component is expressed in plural, it is composed of a singular or singular. Even an expressed component may be composed of a plurality of components.

Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments and should be defined by the claims described below as well as the claims and equivalents.

Also, embodiments of the present disclosure may be combined or combined with each other. For example, it is apparent to those skilled in the art that the respective steps of the embodiments of FIGS. 2 to 11 may be performed in combination or in combination with each other.

Claims (1)

In a method for a terminal to support interworking between different radio access technologies (RATs),
Receiving an MBS service notification from AF or MBSF;
based on the MBS service notification, accessing and registering a first RAT system;
receiving a multicast service through the first RAT system;
Before the terminal moves to the second RAT system, the step of reporting a UE status to AF or AS;
moving to the second RAT system;
according to the identification of the MBS service preparation completion notification in the second RAT system from the AF or AS, modifying a PDU session or PDN connection with a second RAT system and receiving a multicast service through the second RAT system; How to include.

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