Negotiation applicability for inactive or idle reception of multicast services

Abstract

An apparatus in a user equipment is provided, the apparatus comprising: at least one processor and at least one memory containing computer program code, the at least one memory and the computer program code configured by the at least one processor to cause the apparatus to at least receive an indication of whether a transmission mode for inactive / idle reception of multicast is applied for a multicast session, and based on the indication, perform a procedure for enabling reception of the multicast session using the transmission mode for inactive / idle mode reception.

Description

[Technical Field]

[0001] Various exemplary embodiments described herein relate to apparatus, methods, and computer program products for enabling inactive or idle reception of multicast services. [Background technology]

[0002] For the abbreviations used herein, the following meanings apply: AF Application Features AMF Access and Mobility Management Functions AS Application Server (Access and Mobility Management Function) DL Downlink MBS Multicast / Broadcast Service MBSF Multicast / Broadcast Service Function MB-SMF Multicast / Broadcast Session Management Function MB-UPF Multicast / Broadcast User Plane Function NEF Network Exposure Function NG-RAN Next Generation Radio Access Network NRF Network Repository Function PCC Policy Control and Charging PDU Protocol Data Unit QoS Quality of Service RAN Radio Access Network RRC Radio Resource Control SMF Session Management Function TMGI Temporary Mobile Group Identity UE User Equipment

[0003] 5G multicast and broadcast procedures are defined, for example, in TS23.247. Summary of the Invention [Problem to be solved by the invention]

[0004] A UE that joins a multicast session can have inactive / idle reception of the multicast, in which case no feedback about radio reception is sent from the UE to the network.

[0005] However, the quality of service may be affected by inactive / idle reception of multicast. On the one hand, this feature allows reception by a higher number of UEs in the same cell, since those UEs do not send feedback to the network. On the other hand, radio transmissions are not adjusted based on feedback from inactive or idle UEs, and therefore transmission errors may increase.

[0006] The exemplary embodiments are particularly directed to improving the handling of multicast transmissions. [Means for solving the problem]

[0007] According to a first aspect, there is provided an apparatus in a user equipment, the apparatus comprising: at least one processor; and at least one memory containing computer program code, the at least one memory and the computer program code configured by the at least one processor to cause the apparatus to at least receive an indication of whether a transmission mode for inactive / idle reception of multicast applies for a multicast session, and based on the indication, perform a procedure for enabling reception of the multicast session using the transmission mode for inactive / idle mode reception.

[0008] According to a second aspect, there is provided a method in a user equipment, the method comprising: receiving an indication of whether a transmission mode for inactive / idle reception of multicast is applied for the multicast session; and and performing a procedure based on the indication to enable reception of the multicast session using a transmission mode for inactive / idle mode reception. Includes.

[0009] The first and second aspects may be modified as follows:

[0010] An indication as to whether inactive / idle reception of multicast applies for a multicast session may be included in the announcement for the multicast session.

[0011] A join request message for a multicast session may be sent to a network control element, and a join accept message may be received from the network control element, and the join accept message may include an indication as to whether a transmission mode for inactive / idle reception is enabled for the multicast session.

[0012] Support for idle / inactive reception of multicast may be indicated in the join request message.

[0013] A procedure for enabling reception of a multicast session using a transmission mode for inactive / idle mode reception may include monitoring broadcast information of whether a transmission mode for inactive / idle reception of multicast is applied for the multicast session in a cell in which the UE is located.

[0014] While in the RRC inactive or RRC idle state, data for the multicast session may be received.

[0015] When multicast inactive / idle reception is to be applied for a multicast session, feedback regarding reception of the multicast session to the network while the transmission mode for multicast inactive / idle reception is applied may be omitted, or less feedback regarding reception of the multicast session may be sent to the network while the transmission mode for multicast inactive / idle reception is applied than if the transmission mode for multicast inactive / idle reception is not applied for the multicast session.

[0016] According to a third aspect, there is provided an apparatus in a network element for performing an application function, the apparatus comprising: at least one processor and at least one memory containing computer program code, the at least one memory and the computer program code being configured by the at least one processor to cause the apparatus to at least request creation of a multicast session and indicate whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session.

[0017] According to a fourth aspect, there is provided a method in a network element for performing an application function, the method comprising: requesting the creation of a multicast session; Indicating whether transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; Includes.

[0018] The third and fourth aspects may be modified as follows:

[0019] A service announcement for the multicast session may be prepared, targeted to user equipment, the service announcement including an indication of whether a transmission mode for inactive / idle reception of the multicast should be enabled for the multicast session.

[0020] According to a fifth aspect, there is provided an apparatus in a network element for performing multicast broadcast session management functions, the apparatus comprising: at least one processor and at least one memory containing computer program code, the at least one memory and the computer program code being configured by the at least one processor to cause the apparatus to at least manage a multicast session and to cause network elements involved in the multicast session to indicate whether a transmission mode for inactive / idle reception of multicasts should be enabled for the multicast session.

[0021] According to a sixth aspect, there is provided a method in a network element performing multicast broadcast session management functions, the method comprising: managing a multicast session; Indicating to network elements involved in a multicast session whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; Includes.

[0022] The fifth and sixth aspects may be modified as follows:

[0023] An indication may be received from an application function, multicast / broadcast service function, or network exposure function requesting the creation of a multicast session as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session.

[0024] An indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for a multicast session may be pre-configured in the network.

[0025] an indication to network elements involved in a multicast session of whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; An indication to the session management function, in the Nmbsmf_MBSSession_ContextStatusSubscribe response, of whether transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; An indication to the access control function in the Nsmf_PDUSession_UpdateSMContext response of whether transmission mode for multicast inactive / idle reception should be enabled for the multicast session, or An indication to a radio access network node of whether a transmission mode for inactive / idle reception of multicast should be enabled for a multicast session in an N2 session management container. may include at least one of:

[0026] According to a seventh aspect, there is provided an apparatus in a network element performing session management functions, the apparatus comprising: at least one processor; and at least one memory containing computer program code, the at least one memory and the computer program code causing, by the at least one processor, the apparatus to at least receive a join request message for a multicast session from a user equipment; and send a join acceptance message in response to the join request message, the join acceptance message including an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session. It is configured as follows.

[0027] According to an eighth aspect, there is provided a method in a network element performing session management functions, the method comprising: receiving a join request message for a multicast session from a user equipment; sending a join acceptance message in response to the join request message, the join acceptance message including an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; Includes.

[0028] The seventh and eighth aspects may be modified as follows.

[0029] The join acceptance message may include an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled in at least one of an N1 session management container to be sent to the user equipment or an N2 session management container to be sent to the radio access network node.

[0030] The join request message for the multicast session received from the user equipment may include information that the user equipment supports a transmission mode for idle / inactive reception of the multicast.

[0031] From the multicast broadcast session management function, an indication may be received as to whether a transmit mode for inactive / idle reception of multicast should be enabled for the multicast session.

[0032] The sent indication regarding whether the transmit mode for inactive / idle reception of multicast should be enabled for the multicast session is: a received indication from a multicast broadcast session management function; or information received from a user equipment that the user equipment supports the transmit mode for idle / inactive reception of multicast. The determination may be based on at least one of the following:

[0033] According to a ninth aspect, there is provided an apparatus in a network element performing a radio access network node, the apparatus comprising: at least one processor; and at least one memory containing computer program code, the at least one memory and the computer program code being configured, by the at least one processor, to cause the apparatus to receive information related to a multicast session including at least an indication on whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; to determine, based at least in part on the received indication, whether to apply a transmission mode for inactive / idle reception of multicast for the multicast session in at least one radio cell served by the apparatus, and to transmit data of the multicast session in the radio cell using the determined transmission mode.

[0034] According to a tenth aspect, there is provided a method in a network element performing a radio access network node, the method comprising: receiving information related to the multicast session, including an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; determining, based at least in part on the received indication, whether to apply a transmission mode for inactive / idle reception of multicast for the multicast session in at least one wireless cell served by the device; transmitting data of the multicast session in the wireless cell using the determined transmission mode; Includes.

[0035] The ninth and tenth aspects may be modified as follows.

[0036] In at least one radio cell, an indication may be broadcast as to whether a transmission mode for inactive / idle reception of multicast is applied for the multicast session; if a transmission mode for inactive / idle reception of multicast is not applied for the multicast session, user equipments located in the at least one radio cell and joined to the multicast session may be kept in an RRC connected state while the multicast session is active; and if a transmission mode for inactive / idle reception of multicast is applied for the multicast session, user equipments located in the at least one radio cell and joined to the multicast session may be allowed to transition to an RRC inactive state or an RRC idle state while the multicast session is active.

[0037] According to an eleventh aspect, there is provided a computer program product comprising code means for, when executed on a processing means or module, performing a method according to any one of the second, fourth, sixth, eighth and tenth aspects and / or variations thereof. The computer program product may be embodied on a computer readable medium and / or the computer program product may be directly loadable into an internal memory of a computer and / or transmittable over a network by at least one of an upload procedure, a download procedure and a push procedure.

[0038] According to a twelfth aspect, means for receiving an indication of whether a transmission mode for inactive / idle reception of multicast is applied for the multicast session; means for performing a procedure for enabling reception of a multicast session using a transmission mode for inactive / idle mode reception based on the indication; An apparatus is provided comprising:

[0039] According to a thirteenth aspect, means for requesting creation of a multicast session; means for indicating whether transmission mode for inactive / idle reception of multicast should be enabled for a multicast session; An apparatus is provided comprising:

[0040] According to a fourteenth aspect, means for managing a multicast session; means for indicating to network elements involved in a multicast session whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; An apparatus is provided comprising:

[0041] According to a fifteenth aspect, means for receiving a join request message for a multicast session from a user equipment; means for sending a join acceptance message in response to the join request message, the join acceptance message including an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; An apparatus is provided comprising:

[0042] According to a sixteenth aspect, means for receiving information about the multicast session, including an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; means for determining, based at least in part on the received indication, whether to apply a transmission mode for inactive / idle reception of multicast for the multicast session in at least one radio cell served by the device; means for transmitting data of a multicast session in a radio cell using the determined transmission mode; An apparatus is provided comprising:

[0043] These and other objects, features, details and advantages will become more fully apparent from the following detailed description of illustrative embodiments taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0044] [Figure 1A] FIG. 1 illustrates a UE1 according to an exemplary embodiment. [Figure 1B] A diagram illustrating a process performed by UE1 according to an exemplary embodiment. [Figure 2A] FIG. 10 illustrates AF2, according to an exemplary embodiment. [Figure 2B] FIG. 1 illustrates a process performed by AF2, according to an exemplary embodiment. [Figure 3A] FIG. 1 illustrates a MB-SMF3 according to an exemplary embodiment. [Figure 3B] FIG. 1 illustrates a process performed by MB-SMF3 according to an exemplary embodiment. [Figure 4A] FIG. 1 illustrates an SMF4 according to an exemplary embodiment. [Figure 4B] FIG. 1 illustrates a process performed by SMF4 according to an exemplary embodiment. [Figure 5A] FIG. 1 illustrates a RAN node according to an example embodiment. [Figure 5B] FIG. 1 illustrates a process performed by a RAN node according to an example embodiment. [Figure 6A] FIG. 2 illustrates signal flow between several network elements when creating a multicast session, according to an exemplary embodiment. [Figure 6B]FIG. 2 illustrates signal flow between several network elements when creating a multicast session, according to an exemplary embodiment. [Figure 7A] FIG. 1 illustrates MBS session creation without a PCC according to an exemplary embodiment. [Figure 7B] FIG. 1 illustrates MBS session creation without a PCC according to an exemplary embodiment. [Figure 8] FIG. 1 illustrates the establishment of shared distribution towards NG-RAN nodes according to an example embodiment. [Figure 9A] FIG. 1 illustrates a PDU session modification for a UE participating in a multicast session according to an example embodiment. [Figure 9B] FIG. 1 illustrates a PDU session modification for a UE participating in a multicast session according to an example embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0045] A description of exemplary embodiments is provided below, with the understanding that the description is given by way of example only and that the exemplary embodiments described should not be construed as limiting in any way.

[0046] Exemplary embodiments relate to, but are not limited to, 5G multicast and broadcast procedures, for example, as defined in TS 23.247.

[0047] Before describing the exemplary embodiments, some problems addressed by certain exemplary embodiments are described in a little more detail below.

[0048] As mentioned above, in multicast transmission, the quality of service can be affected by inactive / idle reception of the multicast. On the one hand, this feature allows reception by a higher number of UEs in the same cell, since those UEs do not send feedback to the network. On the other hand, radio transmission is not adjusted based on feedback from inactive or idle UEs, and therefore transmission errors may increase. Therefore, according to some embodiments, an external entity creating a multicast session is enabled to control the quality of service (i.e., whether inactive / idle reception of the multicast should be applied).

[0049] More specifically, the external entity creating the multicast session should be able to control the quality of service (i.e., whether inactive / idle reception of multicast should be applied). Inactive / idle mode reception may enable service for more UEs in a cell. However, the quality of service for individual UEs may deteriorate.

[0050] The exemplary embodiments are directed to providing improved handling of multicast transmissions that takes into account the above-mentioned issues.

[0051] In the following, a general overview of some exemplary embodiments will be described with reference to Figures 1A, 1B, 2A, 2B, 3A, 3C, 4A, 4B, 5A and 5C.

[0052] FIG. 1A illustrates UE1 according to an exemplary embodiment. UE1 is an example of a device that may be part of user equipment. Procedures performed by UE1 are illustrated in FIG. 1B. UE1 illustrated in FIG. 1A includes at least one processor 11 and at least one memory 12 containing computer program code. The at least one processor 11, together with the at least one memory 12 and the computer program code, is configured to cause the device to receive an indication of whether a transmission mode for inactive / idle reception is enabled for a multicast session (S11 in FIG. 1B), and, based on the indication, perform a procedure for enabling reception of the multicast session using the transmission mode for inactive / idle reception (S12 in FIG. 1B).

[0053]

[0023] Figure 2A shows AF2 as an example of an apparatus performing an application function, which is an example of an external entity that may request the establishment of a multicast session. Procedures performed by AF2 are shown in Figure 2B. AF2 shown in Figure 2A includes at least one processor 21 and at least one memory 22 containing computer program code. The at least one processor 21, together with the at least one memory 22 and the computer program code, is configured to cause the apparatus to request the creation of a multicast session (S21 in Figure 2B) and to indicate whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session (S22 in Figure 2B).

[0054] FIG. 3A illustrates the MB-SMF3 as an example of an apparatus for performing multicast broadcast session management functions. The procedure executed by the MB-SMF3 is illustrated in FIG. 3B. The MB-SMF3 illustrated in FIG. 3A includes at least one processor 31 and at least one memory 32 containing computer program code. The at least one processor 31, together with the at least one memory 32 and the computer program code, is configured to cause the apparatus to manage a multicast session and to instruct network elements involved in the multicast session (e.g., UE1 illustrated in FIG. 1A, SMF4 illustrated in FIG. 4A, RAN illustrated in FIG. 5A) whether a transmission mode for inactive / idle mode inactive / idle reception of multicast should be enabled for the multicast session (S32 in FIG. 3B).

[0055]

[0033] Figure 4A shows SMF4 as an example of an apparatus that performs session management functions. Procedures executed by SMF4 are shown in Figure 4B. The SMF4 shown in Figure 4A includes at least one processor 41 and at least one memory 42 containing computer program code. The at least one processor 41, together with the at least one memory 42 and the computer program code, is configured to cause the apparatus to receive a join request message for a multicast session from a user equipment (e.g., UE1 shown in Figure 1A) (S41 in Figure 4B) and to send a join acceptance message in response to the join request message, the join acceptance message including information on whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session (S42 in Figure 4B).

[0056] FIG. 5A illustrates a RAN 5 as an example of an apparatus for performing session management functions. Procedures executed by the RAN 5 are illustrated in FIG. 5B. The RAN 54 illustrated in FIG. 5A includes at least one processor 51 and at least one memory 52 containing computer program code. The at least one processor 51, together with the at least one memory 52 and the computer program code, is configured to cause the apparatus to receive information related to a multicast session, including an indication regarding whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session (S51 in FIG. 5B), determine whether to apply a transmission mode for inactive / idle reception of multicast for the multicast session in at least one wireless cell served by the apparatus based at least in part on the received indication (S52 in FIG. 5B), and transmit data of the multicast session in the wireless cell using the determined transmission mode (S53 in FIG. 5B).

[0057] Thus, according to an exemplary embodiment, a new type of information is provided in the network, namely, information regarding whether a transmission mode for inactive / idle reception of multicast should be enabled for a multicast session. Based on this information, network elements involved in the multicast session can configure their operation accordingly. For example, UE1 may not send feedback to the network regarding reception of the multicast session (e.g., not send feedback regarding radio quality) so that less traffic is generated and more UEs can join the multicast session.

[0058] Information about whether a transmission mode for inactive / idle reception of multicast should be enabled for a multicast session may be sent in some message, for example, when the establishment of a multicast session is requested. Alternatively, the information may be pre-configured in the network.

[0059] The term "inactive / idle reception of multicast", sometimes referred to as "passive reception of multicast", means that in response to receiving the multicast, as described above, the receiver (e.g., UE1) does not need to send a response, e.g., there is no feedback.

[0060] Thus, the creator of the multicast session (AF2) and / or the network operator can decide whether there should be inactive / idle reception of multicast in the network or for a particular multicast session, i.e., whether the creator of the multicast session or the network operator should sacrifice radio quality to increase the number of UEs that can join the multicast session, or whether radio quality should be guaranteed at the expense of a reduced number of UEs involved in the multicast session.

[0061] The information on whether a transmission mode for inactive / idle reception of multicast should be enabled for a multicast session may be present in the form of a parameter such as "idle / inactive reception indicator".

[0062] The devices 1 to 4 shown in Figures 1A, 2A, 3A and 4A may include more components than those described above and may further include I / O units 13, 23, 33, 43 that are capable of transmitting to and receiving from other network elements.

[0063] In the following, the above-described procedure will be explained below by referring to some further detailed embodiments, which are also referred to in Fig. 6, which will be explained in more detail later. Fig. 6, which comprises Fig. 6A and Fig. 6B, shows the signal flow between some network elements when creating a multicast session according to an exemplary embodiment, Fig. 6A showing processes A1 to A8, and Fig. 6B showing processes A9 to A14.

[0064] In particular, according to some example embodiments, when an AF requests the creation of a multicast MBS session, the AF indicates whether multicast inactive / idle reception shall be enabled for the session (see also A1 in FIG. 6). The AF may also indicate in the service announcement towards the UE whether the transmission mode for multicast inactive / idle reception should be enabled (see also A3 in FIG. 6).

[0065] Alternatively, the information whether inactive / idle reception of multicast is enabled for a multicast session is pre-configured in the network.

[0066] The MB-SMF indicates to the RAN node whether multicast inactive / idle reception is applicable when the RAN requests shared delivery for a multicast MBS session (see also A10 to A14 in Figure 6).

[0067] The MB-SMF may also indicate to the SMF whether a transmission mode for inactive / idle reception of multicast is enabled when the SMF requests the creation of an MBSSessionContext for an MBS session (see A6 in Figure 6).

[0068] When the SMF replies to the UE's join request, the SMF indicates in the join acceptance whether a transmission mode for inactive / idle reception is enabled for the multicast session based on at least one of the network capabilities, the user equipment capabilities, and information about the multicast session provided by the AF or pre-configured information about the multicast session.

[0069] Inactive / idle reception is applicable for multicast sessions and UEs when: The network and the UE may negotiate a UE transition to an RRC inactive state or an RRC idle state while the UE is in an active multicast state; - the UE listens to multicast transmissions and related radio signaling while in an RRC inactive state or an RRC idle state; and The UE sends less or no radio level feedback regarding multicast reception while in an RRC inactive or RRC idle state.

[0070] When a multicast session is activated and a transmission mode for inactive / idle reception is applied, the network may not page the UE, thus reducing further traffic.

[0071] In the following, an example of how the AF requests the creation of a session will be described by referring to the flowchart shown in Figure 6. The involved elements are the UE, NG-RAN, AMF, SMF, MB-SMF, NEF / MBSF and AF.

[0072] It is assumed that the AF wants to establish a multicast session. At A1, the AF sends an Nnef_MBSSession_Create request (MBS session ID, service type, QoS request, idle / inactive receiving indicator) to the NEF / MBSF. Note that the "idle / inactive receiving indicator" is a new parameter according to this embodiment and is an example of "information on whether the transmission mode for multicast inactive / idle receiving should be enabled for the multicast session."

[0073] At A2, the NEF / MBSF forwards the request (i.e., Nmbsmf_MBSSession_Create request (MBS session ID, service type, idle / inactive receiving indicator)) to the MB-SMF.

[0074] At A3, the MB-SMF establishes a session announcement that includes a new idle / inactive reception indicator.

[0075] It is then assumed that the UE wants to join the multicast session announced by the session announcement. Therefore, at A4, the UE sends a UL NAS message (N1 SM Container (PDU Session Change Request: Join)) to the AMF. At A5, the AMF sends a Nsmf_PDUSession_UpdateSMContext request to the SMF. At A6, the subscribe procedure is performed by sending a Nmbsmf_MBSSession_ContextStatusSubscribe request / response (idle / inactive receiving indicator) between the SMF and the MB-SMF. Note that here a new idle / inactive receiving indicator is included.

[0076] In A7, the SMF sends an Nsmf_PDUSession_UpdateSMContext response (N1 SM container (idle / inactive receiving indicator), N2 SM container (idle / inactive receiving indicator)) to the AMF. Note that this message also includes the new idle / inactive receiving indicator. In A8, the AMF sends an N2 message request to the NG-RAN, including the N1 SM container and N2 SM container received in A7. Then, in A9, the RRC change is performed by sending an RRC message (PDU Session Change Command, N1 SM container (idle / inactive receiving indicator)) between the NG-RAN and the UE.

[0077] If the NG-RAN decides to establish shared distribution for the multicast MBS session, the NG-RAN executes A10 to A13. At A10, the NG-RAN sends an N2 MBS message () to the AMF. At A11, the AMF sends an Nmbsmf_MBSSession_ContextUpdate request to the MB-SMF. At A12, the MB-SMF responds with an Nmbsmf_MBSSession_ContextUpdate response, which includes a new idle / inactive reception indicator. At A13, the AMF sends an N2 MBS message (idle / inactive reception indicator) to the NG-RAN.

[0078] A further embodiment is described by reference to Figure 7, which is based on Figure 7.1.1.2-1 of TS 23.247 and shows MBS session creation without a PCC. In the following, the additions introduced according to the exemplary embodiment are highlighted. Figure 7 includes Figure 7A, which shows processes B1 to B12, and Figure 7B, which shows processes B13 to B22.

[0079] In B1, the AF sends an Nnef_TMGI_AllocateRequest(TMGI number) message to the NEF / MBSF to request allocation of one or more TMGI(s) to identify one or more new MBS sessions. In B2, the NEF checks the authorization of the AF. In B3, the NEF / MBSF discovers and selects an MB-SMF using the NRF or based on local configuration. In B4, the NEF / MBSF sends an Nmbsmf_TMGI_AllocateRequest(TMGI number) message to the MB-SMF. In B5, the MB-SMF allocates one or more TMGI(s) and returns the TMGI(s) to the NEF / MBSF via an Nmbsmf_TMGI_AllocateResponse(TMGI(s), Expiry Time). In B6, the NEF or MBSF responds to the AF by sending an Nnef_TMGI_AllocateResponse(TMGI(s), Expiry Time). In B7, the AF may make a service announcement to the UE.

[0080] In B8, it is assumed that the AF of the content provider requests the creation of a multicast session. In particular, the AF sends an Nnef_MBSSession_Create request to the NEF / MBSF, including the MBS session ID, service type, QoS request, and new idle / inactive reception indicator. In B9, the NEF / MBSF checks the content provider's authorization. In B10, the NEF / MBSF discovers MB-SMF candidates, possibly based on the MBS service area, and selects the MB-SMF as the ingress control node. If a TMGI is included in B8, the NEF / MBSF finds the MB-SMF based on the TMGI. In B11, the NEF / MBSF sends an Nmbsmf_MBSSession_Create request to the MB-SMF, including the MBS session ID, service type, TMGI allocation indication, MBS service area information, ingress transport address request indication, and new idle / inactive reception indicator.

[0081] In B12, if source-specific multicast is provided as the MBS Session ID in B11, the MB-SMF updates its NF profile in the NRF with the serving MBS Session ID. If MBS service area information is received in B11, the MB-SMF updates its NF profile in the NRF with the information. In B13, the MB-SMF locally derives the required QoS parameters.

[0082] In B14, the MB-SMF selects an MB-UPF and sends a session request to the selected MB-UPF. In B15, if requested, the MB-UPF selects an ingress address (IP address and port) and a tunnel endpoint for outgoing data and provides it to the MB-SMF. In B16, in the case of broadcast communication, the MB-SMF continues the procedure toward the AMF and NG-RAN as specified in clause 7.3.1. In B17, the MB-SMF indicates the possibly allocated ingress address to the NEF / MBSF. In B18, which is optional, if the MBSF decides to use the MBSTF, the NEF / MBSF provides the ingress address received in B17 toward the MBSTF as the DL destination. In B19, subject to B18, if requested, the MBSTF selects an ingress address (IP address and port) and provides it to the NEF / MBSF. In B20, the NEF / MBSF-C indicates the possibly allocated ingress address and other parameters (e.g. TMGI) to the AF via a Nnef_MBSSession_Create response ([TMGI], [Allocated Ingress Address]). In B21, which is the same as B7, the AF may also perform a service announcement in this stage. In particular, the service announcement includes a new idle / inactive reception indicator. In B22, in case of multicast communication, depending on the configuration, the UE may join the MBS session as specified in clause 7.2.1.

[0083] A further exemplary embodiment is described by reference to Figure 8, which is based on Figure 7.2.1.4-1 of TS 23.247, showing the establishment of shared distribution towards NG-RAN nodes. In the following, in particular, additions according to the embodiment are described, in particular in which messages the new idle / inactive reception indicator is included.

[0084] In C1, when the NG-RAN node serves at least one UE in the multicast MBS session, the NG-RAN node decides to establish shared distribution for the multicast MBS session. In C2, the NG-RAN sends an N2 MBS Session Request message (MBS Session ID, [Area Session ID], N2 SM Information ([Unicast DL Tunnel Information])) towards the AMF. In C3, the AMF selects the MB-SMF to serve the multicast MBS session, for example, using the NRF discovery service or locally stored information. In C3a, the AMF invokes an Nmbsmf_MBSSession_ContextUpdate request (MBS Session ID, [Area Session ID], N2 SM Information) to the MB-SMF. In C3b, the AMF stores the NG-RAN node's information (e.g., NG-RAN node ID) for subsequent signaling related to the multicast MBS session. Conditionally, at C4, if the MB-SMF receives unicast DL tunnel information at C3, the MB-SMF configures the MB-UPF to send multicast data for the multicast MBS session (or, if an area session ID is received, location-dependent content of the multicast MBS session) towards that GTP tunnel endpoint via unicast transport. At C5, the MB-SMF stores the AMF's information (e.g., AMF ID) in the MBS multicast session context (or, if an area session ID is received, in the location-dependent part of the multicast MBS session context) to enable subsequent signaling towards that AMF.

[0085] At C6, the MB-SMF sends an Nmbsmf_MBSSession_ContextUpdate response to the AMF. In particular, this response includes the new idle / inactive reception indicator. At C7, the AMF sends an N2 MBS Session Response message to the NG-RAN node. This response message also includes this response and the new idle / inactive reception indicator.

[0086] Another exemplary embodiment is described below with reference to Figure 9, which is based on Figure 7.2.1.3-1 of TS 23.247 and shows a PDU session modification for a UE joining a multicast session. Figure 9 includes Figure 9A, which shows processes D1 to D10, and Figure 9B, which shows processes D11 to D19. This embodiment describes a variant in which the UE can indicate its support for idle / inactive reception in the join request, and the network can use this as a criterion to indicate in the join reply whether idle / inactive reception applies for the MBS session and the UE.

[0087] At D1, to join a multicast group, the UE sends a PDU Session Modify Request for the associated PDU session, which further includes one or several MBS session IDs and a join request. In particular, the message sent to the AMF at D1a includes a new idle / inactive reception indicator. At D2, based on the received MBS session ID and join request, the SMF determines that this is an MBS session join request. At D3, for each MBS session at D1, if the SMF did not subscribe to the MBS session context, the SMF subscribes to event notifications related to the multicast MBS session and invokes a Nmbsmf_MBSSession_ContextStatusSubscribe request (MBS session ID) towards the MB-SMF to request information about the MBS session context. The MB-SMF responds with information about the indicated multicast MBS session in a Nmbsmf_MBSSession_ContextStatusSubscribe response. The request and response also include a new idle / inactive reception indicator.

[0088] In D4, the SMF performs the authorization check described in clause 6.41 of TS 23.247. In D5, if the join request is accepted, the SMF responds to the AMF through an Nsmf_PDUSession_UpdateSMContext response (N2 SM information (PDU Session ID, MBS Session ID, [Updated PDU Session Information], [Mapping information between(one or more) unicast QoS flows and(one or more) multicast QoS flows]), N1 SM Container (PDU Session Modify Command)). This response also includes a new idle / inactive reception indicator.

[0089] At D6, an N2 message containing the multicast MBS session information and PDU session modification information is sent to the NG-RAN. As mentioned above, this message also contains the new idle / inactive reception indicator.

[0090] The following processes D7 to D19 correspond exactly to steps 7 to 19 in Figure 7.2.1.3-1 of TS 23.247.

[0091] Therefore, according to some example embodiments, a new idle / inactive reception indicator may be included in a different message so that corresponding network elements may be informed whether to apply idle / inactive reception for the multicast session.

[0092] The exemplary embodiments described above are examples only and may be modified.

[0093] The names of network elements, protocols, and methods are based on the current standard. In other versions or other technologies, the names of these network elements and / or protocols and / or methods may be different as long as they provide the corresponding functions.

[0094] In general, the exemplary embodiments may be implemented by computer software stored in memories (memory resources, memory circuits) 12, 22, 32, 42, 52 and executable by processors (processing resources, processing circuits) 11, 21, 31, 41, 51, or by hardware, or by a combination of software and / or firmware and hardware.

[0095] As used in this application, the term "circuit" refers to any of the following: (a) a hardware-only circuit implementation (e.g., an implementation in analog and / or digital circuitry only); and (b) (when applicable), (i) a combination of processor(s) or (ii) a combination of circuitry and software (and / or firmware), such as processor(s) / software, software, and memory(s) (including digital signal processor(s)), that cooperate to cause a device, such as a mobile phone or server, to perform various functions; and (c) Any circuitry, such as a microprocessor(s) or portion of a microprocessor(s), that requires software or firmware for its operation even when the software or firmware is not physically present.

[0096] This definition of "circuit" applies to all uses of the term in this application, including any claims. As a further example, the term "circuit" as used in this application will also cover simply an implementation of a processor (or processors) or portion of a processor and its (their) accompanying software and / or firmware. The term "circuit" will also cover, for example, and where applicable to certain claim elements, a baseband integrated circuit or an application processor integrated circuit for a mobile phone, or a similar integrated circuit in a server, cellular network device, or other network device.

[0097] The terms "connected" or "coupled," or any variation thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling or connection between elements may be physical, logical, or a combination thereof. As employed herein, two elements may be considered "connected" or "coupled" together by the use of one or more wires, cables, and printed electrical connections, as well as by the use of electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency, microwave, and optical (both visible and invisible) regions, as non-limiting examples.

[0098] The memories (memory resources, memory circuits) 12, 22, 32, 42, 52 may be of any type suitable for the local technology environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed and removable memory, and non-transitory computer-readable media. The processors (processing resources, processing circuits) 11, 21, 31, 41, 51 may be of any type suitable for the local technology environment and may include, by way of non-limiting example, one or more of general-purpose computers, special-purpose computers, microprocessors, digital signal processors (DSPs), and processors based on multi-core processor architectures.

[0099] It should be understood that the exemplary embodiments described above are illustrative and should not be construed as limiting. Various modifications and adaptations may occur to those skilled in the art without departing from the true spirit and scope of the exemplary embodiments.

[0100] Some exemplary embodiments provide:

[0101] 1. A method in a user equipment, comprising: receiving an indication of whether a transmission mode for inactive / idle reception of multicast is applied for the multicast session; and performing a procedure based on the indication to enable reception of the multicast session using a transmission mode for inactive / idle mode reception. A method comprising:

[0102] A further method, wherein an indication as to whether inactive / idle reception of multicast applies for a multicast session is included in an announcement for the multicast session.

[0103] The method is: sending a join request message for the multicast session to a network control element; receiving a join acceptance message from a network control element, the join acceptance message including an indication as to whether a transmission mode for inactive / idle reception is enabled for the multicast session; It may further include:

[0104] The method is: Indicating support for multicast idle / inactive reception in the join-request message It may further include:

[0105] In the method, a procedure for enabling reception of a multicast session using a transmission mode for inactive / idle mode reception may include monitoring broadcast information of whether a transmission mode for inactive / idle reception of multicast is applied for the multicast session in a cell in which the UE is located.

[0106] The method is: Receiving data for a multicast session while in RRC inactive or RRC idle state It may further include:

[0107] The method when multicast inactivity / idle reception should be applied for a multicast session: Omitting feedback to the network about the reception of the multicast session while the transmission mode for multicast inactive / idle reception is applied, or While a sending mode for multicast inactivity / idle reception is applied, sending less feedback regarding reception of the multicast session to the network than if the sending mode for multicast inactivity / idle reception was not applied for the multicast session. It may further include:

[0108] Some example embodiments may provide a method in a network element performing an application function, the method comprising: requesting the creation of a multicast session; Indicating whether transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; Includes:

[0109] The method is: Preparing a service announcement for a multicast session, targeted to a user equipment, the service announcement including an indication of whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session. It may further include:

[0110] Some example embodiments may further provide a method in a network element performing multicast broadcast session management functions, the method comprising: managing a multicast session; Indicating to network elements involved in a multicast session whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; Includes:

[0111] The method is: receiving an indication from an application function, a multicast / broadcast service function, or a network exposure function requesting the creation of a multicast session as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; It may further include:

[0112] In the method, an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for a multicast session may be pre-configured in the network.

[0113] 20. The method, comprising: providing an indication to network elements involved in a multicast session of whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session by: Indication to the session management function, in the Nmbsmf_MBSSession_ContextStatusSubscribe response, of whether transmission mode for multicast inactive / idle reception should be enabled for the multicast session; An indication to the access control function, in the Nsmf_PDUSession_UpdateSMContext response, of whether transmission mode for multicast inactive / idle reception should be enabled for the multicast session; or An indication to a radio access network node in an N2 session management container of whether a transmission mode for inactive / idle reception of multicast should be enabled for a multicast session. may include at least one of:

[0114] Some example embodiments may provide a method in a network element performing session management functions, the method comprising: receiving a join request message for a multicast session from a user equipment; sending a join acceptance message in response to the join request message, the join acceptance message including an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; Includes:

[0115] In the method, the participation acceptance message: An indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled, an N1 session management container to be sent to the user equipment; or N2 session management container to be sent to a radio access network node It may be included in at least one of the following.

[0116] In the method, a join request message for a multicast session received from a user equipment may include information that the user equipment supports a transmission mode for idle / inactive reception of multicast.

[0117] The method is: receiving an indication from a multicast broadcast session management function as to whether a transmit mode for inactive / idle reception of multicast should be enabled for the multicast session; It may further include:

[0118] The method, wherein the sent indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for a multicast session comprises: a received indication from a multicast / broadcast session management function; or Received information from the user equipment that the user equipment supports a transmission mode for idle / inactive reception of multicast. The determination may be based on at least one of the following:

[0119] Some example embodiments may provide a method in a network element performing a radio access network node, the method comprising: receiving information related to the multicast session, including an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; determining, based at least in part on the received indication, whether to apply a transmission mode for inactive / idle reception of multicast for the multicast session in at least one wireless cell served by the device; transmitting data of the multicast session in the wireless cell using the determined transmission mode; Includes:

[0120] The method is: broadcasting, in at least one radio cell, an indication as to whether a transmission mode for inactive / idle reception of multicast is applied for the multicast session; If a transmission mode for multicast inactive / idle reception is not applied for the multicast session, keeping user equipments that have joined the multicast session and are located within at least one radio cell in an RRC connected state while the multicast session is active; If a transmission mode for multicast inactive / idle reception is applied for a multicast session, allowing user equipments that have joined the multicast session and are located in at least one radio cell to transition to an RRC inactive state or an RRC idle state while the multicast session is active; It may further include:

Claims

1. 1. An apparatus in a user equipment, comprising: and at least one processor and at least one memory containing computer program code, wherein the at least one memory and the computer program code are configured by the at least one processor to cause the apparatus to at least: receiving an indication of whether a transmission mode for inactive / idle reception of multicast is applied for the multicast session; Based on the indication, a procedure is performed to enable reception of the multicast session using a transmission mode for inactive / idle mode reception. An apparatus configured as follows.

2. 10. The apparatus of claim 1, wherein an indication as to whether inactive / idle reception of multicast applies for the multicast session is included in the announcement for the multicast session.

3. At least one memory and computer program code are configured by at least one processor to cause the apparatus to: causing a network control element to send a join request message for the multicast session; receiving a join acceptance message from a network control element, the join acceptance message including an indication as to whether a transmission mode for inactive / idle reception is enabled for the multicast session; The apparatus of claim 1 further configured to:

4. At least one memory and computer program code are configured by at least one processor to cause the apparatus to: Indicate support for multicast idle / inactive reception in join request messages The device according to claim 3 , configured to:

5. 5. The apparatus according to claim 1, wherein the procedure for enabling reception of a multicast session using a transmission mode for inactive / idle mode reception comprises monitoring broadcast information of whether a transmission mode for inactive / idle reception of multicast applies for the multicast session in a cell in which the UE is located.

6. At least one memory and computer program code are configured by at least one processor to cause the apparatus to: Allows reception of multicast session data while in RRC inactive or RRC idle state 5. The apparatus of claim 1, further configured to:

7. When multicast inactivity / idle reception is to be applied for a multicast session, at least one memory and computer program code are configured to cause the apparatus, by at least one processor, to: Omitting feedback to the network about the reception of the multicast session while the transmission mode for multicast inactivity / idle reception is applied, or While a transmission mode for multicast inactivity / idle reception is applied, less feedback regarding reception of the multicast session is sent to the network than if the transmission mode for multicast inactivity / idle reception were not applied for the multicast session.

5. The apparatus of claim 1, further configured to:

8. 1. An apparatus in a network element that performs an application function, comprising: and at least one processor and at least one memory containing computer program code, wherein the at least one memory and the computer program code are configured by the at least one processor to cause the apparatus to at least: Requests the creation of a multicast session, Indicates whether transmission mode for inactive / idle reception of multicast should be enabled for the multicast session. An apparatus configured as follows.

9. At least one memory and computer program code are configured by at least one processor to cause the apparatus to: Preparing a service announcement for a multicast session, targeted to a user equipment, the service announcement including an indication of whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session. The apparatus of claim 8 further configured to:

10. 1. An apparatus in a network element performing session management functions, comprising: and at least one processor and at least one memory containing computer program code, wherein the at least one memory and the computer program code are configured by the at least one processor to cause the apparatus to at least: receiving a join request message for a multicast session from a user equipment; Sending a join acceptance message in response to the join request message, the join acceptance message including an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session. It is configured as follows: The join acceptance message includes an indication as to whether a send mode for inactive / idle reception of multicast should be enabled. an N1 session management container to be sent to the user equipment; or N2 session management container to be transmitted to a radio access network node The device includes at least one of the following:

11. 11. The apparatus of claim 10, wherein a join request message for a multicast session received from a user equipment includes information that the user equipment supports a transmission mode for idle / inactive reception of multicast.

12. At least one memory and computer program code are configured by at least one processor to cause the apparatus to: Receive an indication from a multicast / broadcast session management function regarding whether a transmit mode for inactive / idle reception of multicast should be enabled for the multicast session.

12. The device according to claim 10 or 11, configured to:

13. The sent indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session is: a received indication from a multicast / broadcast session management function, or Received information from the user equipment that the user equipment supports a transmission mode for idle / inactive reception of multicast. The apparatus of claim 10 or 11, wherein the determination is based on at least one of:

14. An apparatus in a network element performing a radio access network node, comprising: and at least one processor and at least one memory containing computer program code, wherein the at least one memory and the computer program code are configured by the at least one processor to cause the apparatus to at least: receiving, in an N2 session management container, information regarding the multicast session, including an indication as to whether a transmission mode for inactive / idle reception of multicast should be enabled for the multicast session; determining, based at least on the received indication, whether to apply a transmission mode for inactive / idle reception of multicast for the multicast session in at least one radio cell served by the device; The determined transmission mode is used to transmit data of a multicast session in a wireless cell. An apparatus configured as follows.

15. At least one memory and computer program code are configured by at least one processor to cause the apparatus to: - broadcasting, in at least one radio cell, an indication as to whether a transmission mode for inactive / idle reception of multicast is applied for the multicast session; if a transmission mode for inactive / idle reception of multicast is not applied for the multicast session, keeping user equipments that have joined the multicast session and are located in at least one radio cell in an RRC connected state while the multicast session is active; If a transmission mode for inactive / idle reception of multicast is applied for the multicast session, allowing user equipments that have joined the multicast session and are located in at least one radio cell to transition to an RRC inactive state or an RRC idle state while the multicast session is active; The apparatus of claim 14 , further configured to cause at least one of:

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