System and method for multicast data traffic service continuity in multicast broadcast service operation during radio resource control state transitions

Abstract

This disclosure describes systems and methods for multicast data traffic service continuity under multicast broadcast service (MBS) operation during radio resource control (RRC) state or mode transitions. In some embodiments, a user equipment (UE) receives an RRC release message from a network while in an RRC connected mode, the RRC release message including an RRC inactive mode point-to-multipoint (PTM) configuration, the RRC inactive mode point-to-multipoint (PTM) configuration using an MBS session for receiving multicast data traffic while the UE is in the RRC inactive mode; in response to the RRC release message, entering an RRC inactive mode from an RRC connected mode; and using the RRC inactive mode PTM configuration to receive multicast data traffic for the MBS session from the network when the UE is in the RRC inactive mode. Also described are instances in which the UE instead re-uses the RRC connected mode PTM configuration after transitioning to the RRC inactive mode. Similar network behavior is described.

Description

Technical Field

[0001] The present application generally relates to wireless communication systems, including wireless communication systems for transmitting multicast data traffic according to a multicast broadcast service (MBS) arrangement. Background Art

[0002] Wireless mobile communication technologies use various standards and protocols to transmit data between base stations and wireless communication devices. For example, wireless communication system standards and protocols may include the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) (e.g., 4G), 3GPP New Radio (NR) (e.g., 5G), and the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard for wireless local area networks (WLANs) (commonly referred to within industry organizations as WLANs). ).

[0003] As envisioned by 3GPP, different wireless communication system standards and protocols may use various radio access networks (RANs) for communication between base stations (sometimes also referred to as RAN nodes, network nodes, or simply nodes) of the RAN and wireless communication devices referred to as user equipment (UE). 3GPP RANs may include, for example, Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE) RAN (GERAN), Universal Terrestrial Radio Access Network (UTRAN), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and / or Next Generation Radio Access Network (NG-RAN).

[0004] Each RAN can use one or more radio access technologies (RATs) for communication between base stations and UEs. For example, GERAN implements GSM and / or EDGE RAT, UTRAN implements Universal Mobile Telecommunications System (UMTS) RAT or other 3GPP RAT, E-UTRAN implements LTE RAT (sometimes referred to as LTE), and NG-RAN implements NR RAT (the NR RAT is sometimes referred to as 5G RAT, 5G NR RAT, or NR in this document). In some deployments, E-UTRAN may also implement NR RAT. In some deployments, NG-RAN may also implement LTE RAT.

[0005] The base station used by the RAN may correspond to the RAN. An example of an E-UTRAN base station is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (also commonly denoted as an evolved Node B, enhanced Node B, eNodeB, or eNB). An example of an NG-RAN base station is a Next Generation Node B (also sometimes referred to as a gNodeB or gNB).

[0006] The RAN provides communication services together with external entities through its connection with the Core Network (CN). For example, E-UTRAN may utilize the Evolved Packet Core (EPC) and NG-RAN may utilize the 5G Core Network (5GC). BRIEF DESCRIPTION OF THE DRAWINGS

[0007] To easily identify the discussion of any particular element or act, the most significant digit(s) in a reference number refers to the drawing number that first introduces the element.

[0008] Figure 1A A flow chart illustrating MBS broadcast configuration between a UE and a base station according to the embodiments discussed herein.

[0009] Figure 1B The MCCH-Config IE and CFR-ConfigMCCH-MTCH IE according to some embodiments are illustrated, which may be present in the SIB according to the two-step MBS broadcast configuration.

[0010] Figure 1C Configuration information that may be present in an MCCH transmission according to the embodiments discussed herein is illustrated.

[0011] Figure 2A A diagram corresponding to an MBS-to-MBS handover of a UE from a source base station to a target base station is illustrated according to some embodiments.

[0012] Figure 2B A diagram corresponding to MBS-to-unicast switching of a UE from a source base station to a target base station is illustrated according to some embodiments.

[0013] Figure 3 A flow chart is illustrated for signaling between a UE and a network serving the UE during an MRB bearer type change according to embodiments discussed herein.

[0014] FIG. 4A to FIG. 4E Various IEs used / considered as MBS configuration within an MBS multicast service scenario assuming an RRC connected mode according to embodiments herein are illustrated.

[0015] Figure 5 The MRB PDCP Configuration IE that can be used in the configuration of the MBS broadcast service is illustrated.

[0016] Fig. 6A illustrates an RLC bearer configuration IE that can be used in the configuration of an MBS multicast service, and Figure 6B and Figure 6C Together, PDCP configuration IEs that may be used in the configuration of MBS multicast services are illustrated.

[0017] Figure 7 A flow chart illustrating a method for service continuity of data traffic of an MBS multicast service between a UE and a network according to embodiments of this document.

[0018] Fig. 8A A flow chart illustrating a method for service continuity of data traffic of an MBS multicast service between a UE and a network according to embodiments of this document.

[0019] Figure 8B A flow chart illustrating a method for service continuity of data traffic of an MBS multicast service between a UE and a network according to embodiments of this document.

[0020] Fig. 9 Various options for transmitting MBS session information from the network to the UE according to the embodiments discussed herein are illustrated.

[0021] Fig.10 A method of a UE according to the embodiments discussed herein is illustrated.

[0022] Fig.11 A method of a RAN according to the embodiments discussed herein is illustrated.

[0023] Fig.12 A method of a UE according to the embodiments discussed herein is illustrated.

[0024] Fig.13 A method of a RAN according to the embodiments discussed herein is illustrated.

[0025] Fig.14 An example architecture of a wireless communication system according to embodiments disclosed herein is illustrated.

[0026] Fig.15 A system for performing signaling between a wireless device and a network device according to embodiments disclosed herein is illustrated. DETAILED DESCRIPTION

[0027] The various embodiments are described with respect to a UE. However, reference to a UE is provided for illustrative purposes only. The example embodiments may be used with any electronic component that can establish a connection with a network and is configured with hardware, software, and / or firmware for exchanging information and data with the network. Therefore, a UE as described herein is used to represent any suitable electronic component.

[0028] Enhancements to multicast / broadcast functionality may be considered as part of a multicast broadcast service (MBS) implementation in a wireless communication system (e.g., a 3GPP NR Release 17 (Rel-17) MBS implementation). As part of such considerations, support for multicast reception by UEs in a radio resource control (RRC) inactive state or mode (RRC_INACTIVE) may be specified. As part of this specification, aspects of a point-to-multipoint (PTM) configuration for a UE receiving multicast data traffic while in an RRC inactive mode may be considered. In addition, the impact on the mobility and / or state transitions of a UE receiving multicast data traffic while in an RRC inactive mode may be considered.

[0029] Other enhancements to the MBS multicast / broadcast functionality may include consideration of Uu signaling enhancements to allow UEs to use shared processing for both MBS broadcast reception and MBS unicast reception, including reporting of, for example, UE capabilities and related assistance information regarding simultaneous unicast reception and MBS broadcast reception from the same or different operators when the UE is in RRC connected state or more (RRC_CONNECTED). Still further enhancements may involve improvements in resource efficiency for MBS reception in RAN sharing scenarios.

[0030] Here, MBS broadcast services and MBS multicast services, among others, are discussed, compared, and contrasted. In various wireless communication systems (e.g., various 3GPP wireless communication systems) that implement MBS services, MBS broadcast services are a first type of MBS service, while MBS multicast services are a second (different) type of MBS service. For example, an MBS broadcast service may not require a UE to join an associated session in order to receive associated data traffic, which may be required in the case of an MBS multicast service. As discussed in detail herein, MBS broadcast services and MBS multicast services may be configured in different ways.

[0031] Implementation plan for MBS broadcast service

[0032] Figure 1A Flowchart 102 illustrates MBS broadcast configuration between UE 104 and network 106 (eg, a base station of the network) according to embodiments discussed herein. Flowchart 102 may correspond to, for example, 3GPP Rel-17 MBS broadcast configuration.

[0033] Flowchart 102 may represent two-step MBS broadcast configuration acquisition for a UE 104 when the UE is in any of an RRC connected mode, an RRC idle mode (RRC_IDLE, sometimes also referred to as an RRC idle state), and / or an RRC inactive mode. As shown, UE 104 first receives an MBS configuration for an MBS broadcast session occurring via a multimedia broadcast / multicast service (MBMS) point-to-multipoint control channel (MCCH) on SIB 108 (shown as "SIBx" in flowchart 102).

[0034] Figure 1B MCCH-Config information element (IE) 112 and CFR-ConfigMCCH-MTCH IE 114 are illustrated according to some embodiments, which may be present in a SIB (e.g., SIB 108) according to a two-step MBS broadcast configuration. MCCH-Config IE 112 and CFR-ConfigMCCH-MTCH IE 114 are shown here as being arranged according to some 3GPP NRRel-17 embodiments.

[0035] As shown, the MCCH configuration IE 112 provides the UE with MCCH repetition period and offset information 116, MCCH window starting time slot information 118, MCCH window duration information 120, and MCCH modification period information 122.

[0036] In addition, the CFR-ConfigMCCH-MTCH IE 114 provides the UE with location and bandwidth broadcast information 124, physical downlink shared channel (PDSCH) configuration information 126 of the MCCH, and common control resource set information 128.

[0037] Back to Figure 1A 102, after receiving the SIB 108, the UE then receives the corresponding MCCH transmission 110 (according to the MCCH configuration provided in the SIB 108). As shown, the MCCH transmission 110 may include a physical downlink control channel (PDCCH) 130 scheduled using an MCCH radio network temporary identifier (MCCH-RNTI) and an MBS broadcast configuration 132 (arriving via the MCCH / PDSCH).

[0038] The MBS broadcast configuration present in the MCCH transmission 110 provides a list of all broadcast services with ongoing sessions transmitted on a multicast traffic channel (MTCH) and associated information for the broadcast session (e.g., MBS session identifier (ID), group radio network temporary identifier (RNTI) (G-RNTI) and scheduling information, neighboring cell information for MTCH, etc.).

[0039] Figure 1C Configuration information 134 that may be present in an MCCH transmission 110 according to the embodiments discussed herein is illustrated. As shown, the MCCH transmission 110 may include an MBS session information list IE 136, an MBS neighbor cell list IE 138, a discontinuous reception (DRX) configuration PTM list IE 140, a PDSCH configuration for MTCH IE 142, and an MTCH to synchronization signal block (SSB) mapping window list IE 144.

[0040] The MBS session information list IE 136 may correspond to the first IE 146, which may include an MBS session ID IE, a G-RNTI IE, an MBS radio bearer (MRB) list broadcast IE, an MTCH scheduling information IE, an MTCH neighboring cell IE, a PDSCH configuration index IE, and an MTCH to SSB mapping window index IE, as shown in the figure.

[0041] The MBS neighbor cell list IE 138 may correspond to a second IE 148, which may include a physical cell ID IE and a carrier frequency IE, as shown.

[0042] The DRX configuration PTM list IE 140 may correspond to a third IE 150, which may include a DRX on duration timer for the PTM IE, a DRX inactivity timer for the PTM IE, a DRX hybrid automatic repeat request (HARQ) round trip time (RTT) timer for the downlink of the PTM IE, a DRX retransmission timer for the downlink of the PTM IE, a DRX long cycle start offset for the PTM IE, and a DRX slot offset for the PTM IE, as shown in the figure.

[0043] The PDSCH configuration for MTCH IE 142 may correspond to a fourth IE 152, which may include a PDSCH configuration list IE, a PDSCH time domain allocation list IE, an added modified rate matching mode list IE, a modulation and coding scheme (MCS) table IE, and an X overhead IE, as shown.

[0044] As shown, the MTCH to SSB mapping window list IE 144 may correspond to the MTCH to SSB mapping window period offset IE 154.

[0045] like Figure 1CAs shown by the arrows in the figure, the MTCH scheduling information IE of the first IE 146 can be understood as being related to the third IE 150, the PDSCH configuration index IE of the first IE 146 can be understood as being related to the fourth IE 152, and the MTCH to SSB mapping window index IE of the first IE 146 can be understood as being related to the MTCH to SSB mapping window period offset IE154.

[0046] Return to Figure 1A Flowchart 102: As shown, upon receiving the MCCH transmission 110, the UE establishes 156 a broadcast MRB for the corresponding MRB session. The UE does this without reference / using any MRB indicated by the network (note that no MRB information is provided in the MCCH transmission 110). As part of the process, the UE establishes a corresponding Service Data Adaptation Protocol (SDAP) entity, a corresponding Packet Data Convergence Protocol (PDCP) entity, and a corresponding Radio Link Control (RLC) entity. In addition, the UE applies the appropriate physical layer (PHY) configuration and notifies the upper layer of the corresponding Temporary Mobile Group Identity (TMGI).

[0047] The UE then continues to receive onward MBS broadcast service transmissions 158 as shown.

[0048] MBS multicast service implementation plan

[0049] In some wireless communication systems, a UE may continue to receive MBS multicast services via PTM or Point-to-Point (PTP) in a new cell during handover.

[0050] Figure 2A A diagram 202 is illustrated corresponding to an MBS to MBS handover 204 of a UE 206 from a source base station 208 to a target base station 210 according to some embodiments. As shown, a CN 212 receives a data packet (at Figure 2A 2) for distribution according to MBS sessions 216 of the MBS multicast service. Copies of these same data packets (with the same sequence number (SN) within the MBS session 216) are delivered by the CN 212 to each of the source base station 208 and the target base station 210. Thus, both the source base station 208 and the target base station 210 are equipped to provide the UE 206 with data traffic on the MBS data radio bearer (DRB) 218 ​​(or MRB 218) corresponding to the MBS session 216, so that reception of data traffic over the MBS multicast service is seamless with respect to the (arbitrary) timing of the MBS to MBS handover 204.

[0051] Figure 2BA diagram 220 corresponding to an MBS-to-unicast handover 222 of a UE 224 from a source base station 226 to a target base station 228 is illustrated in accordance with some embodiments. As shown, a CN 230 receives data packets from an MBS server 232 for distribution according to an MBS session 236 of an MBS multicast service. Copies of these same data packets (according to the MBS session 236) are delivered by the CN 230 to the source base station 226, and copies of those data packets (reconstructed for a unicast protocol data unit (PDU) session 238) are delivered by the CN 212 to the target base station 210. Thus, both the source base station 208 and the target base station 210 are equipped to provide data traffic on an MBS DRB 234 (or MRB 234) to the UE 206, such that reception of data traffic over the MBS multicast service is seamless with respect to the (arbitrary) timing of the MBS-to-unicast handover 222.

[0052] Note that in the definition for some wireless communication systems, lossless handover of MBS multicast services is supported, at least for the PTP to PTP case. In addition, downlink (DL) PDCP SN synchronization and continuity between the source cell and the target cell may need to be guaranteed. Therefore, in some cases, the source base station may forward data to the target base station, and the target base station may then deliver the forwarded data. The UE may be configured by the network to provide a PDCP status report for the MRB of the multicast session during handover.

[0053] To minimize the loss during MRB bearer type change, the network (eg, via the base station) may configure the UE to send a PDCP status report when the MRB bearer type changes (eg, from PTM to PTP). Figure 3 Illustrated is a flow chart 302 for signaling between a UE 304 and a network 306 serving the UE during an MRB bearer type change according to embodiments discussed herein.

[0054] like Figure 3 As shown, network 306 first sends a first RRC reconfiguration message 308 to UE 304. As shown, first RRC reconfiguration message 308 may include information about an MRB used with PTP and PTM MBS multicast services between UE 304 and network 306 (eg, an MRB ID).

[0055] The network 306 then performs an MBS transmission 310 towards the UE according to the information in the first RRC reconfiguration message 308 (and the UE receives the MBS transmission 310 ).

[0056] The network then sends a second RRC reconfiguration message 312 to the UE 304. The second RRC reconfiguration message 312 may correspond to, for example, a bearer type change. As shown, the second RRC reconfiguration message 312 includes information (e.g., an MRB ID) about an MRB for an MBS session for which the network wishes to use seamlessly during the MRB bearer type change. The MRB in question may be the same MRB discussed with respect to the first RRC reconfiguration message 308, which is now configured with (only) a PTP configuration, through which service continuity will continue to be provided. In addition, as shown, the second RRC reconfiguration message 312 may also include an inquiry for the UE 304 to provide a PDCP status report (SR) to the network 306.

[0057] Upon receiving the second RRC reconfiguration message 312, the UE stores 314 various ongoing PDCP PDU / service data unit (SDU) data packets ( Figure 3 An example involves storing packets with SNs 6, 7, 8, 9, and 11 to 19) in preparation for an upcoming MRB bearer type change.

[0058] The UE 304 then sends a PDCP status report 316 to the network. The PDCP status report 316 informs the network of the current PDCP status at the UE (e.g., which data packets have been received by the UE 304), so that the network is equipped to resume the MBS session via MRB and according to the (only) PTP configuration at the appropriate packet range.

[0059] Based on the PDCP status report 316, the network 306 sends the appropriate range of PDCP data packets 318 ( Figure 3 The example uses packets with SN 5, 10 and 20-100 and beyond). The UE is configured to correctly receive these data packets for use based on the preservation of the same MRB and the same MBS context as provided to the UE 304 in the second RRC reconfiguration message 312.

[0060] Upon receiving 320 packets with SN 5 and 10 from the network 306, the UE delivers all previously stored PDCP SDU / PDU packets (e.g. packets with SN 6, 7, 8, 9 and 11 to 19) to upper layers and then continues to receive new PDCP SDU / PDU packets (e.g. packets with SN 20-100 and beyond) from the network 306 using the new (only) PTP configuration, again using the MRB and MBS context retained via the information present in the second RRC reconfiguration message 312.

[0061] In some wireless communication systems, the network provides MBS configuration for multicast cases via RRC reconfiguration messages. Such configuration message transmission may include various parts. The first part of the MBS configuration message transmission may include the MRB configuration in the RadioBearerConfig IE. The second part of the MBS configuration message may include the PTM-related G-RNTI and DRX configuration in the MAC-CellGroupConfig IE. The third part of the MBS configuration message transmission may include the PTM PDCCH / PDSCH configuration in the common frequency resource (CFR) configuration within each bandwidth part (BWP) DL configuration. The fourth part of the MBS configuration message transmission may include HARQ feedback related configuration information in the BWP configuration.

[0062] FIG. 4A to FIG. 4E Various IEs used / considered as MBS configuration within an MBS multicast service scenario assuming an RRC connected mode according to embodiments herein are illustrated. Figure 4A The example adds a modified MRB IE 402. Figure 4B MAC cell group configuration IE 404 is illustrated. Figure 4C The BWP downlink dedicated IE 406 is illustrated. Figure 4D The MBS RNTI specific configuration IE 408 is illustrated, and Figure 4E The DRX configuration IE 410 for PTM is illustrated. FIG. 4A to FIG. 4E The IEs are provided for illustrative purposes (e.g., for comparison with the configuration IEs of MBS configuration information that may be provided with an MBS broadcast service scenario as provided herein), and therefore not all details of each such IE are explicitly described herein.

[0063] Pay special attention to: Figure 4A The added and modified MRB IE 402 includes an MRB identity IE 412 and an MRB identity IE 414, either of which can be used to inform the UE of the relevant (e.g., previous) MRB ID, which will continue to be used during the (new / newly configured) MBS multicast service corresponding to the configuration information. It should be noted that similar such IEs (or IEs with the same information) may not exist in the configuration of MBS broadcast services in some wireless communication networks (e.g., refer to the discussion of such configuration of MBS broadcast services as described above).

[0064] In other words, with respect to some wireless communication systems (e.g., some 3GPP NR wireless communication systems), it should be understood that, among other things, the use, behavior, and implementation of MRBs differ between the configuration of an MBS broadcast service and the configuration of an MBS multicast service. As discussed, MRB ID information may be provided only in the case of a configuration of an MBS multicast service, but not in the case of a configuration of an MBS broadcast service. Thus, the MRB structure is different for different MRB types.

[0065] Regarding this case, it can be said that the configuration of the MRB used with the MBS multicast service is correspondingly richer than the configuration of the MRB MBS broadcast service. Figure 5 An MRB PDCP Configuration IE 502 is illustrated which may be used in the configuration of an MBS broadcast service. As will be seen in retrospect, no mechanism is provided in the MRB PDCP Configuration IE 502 for conveying the MRB ID or other MRB-related information.

[0066] Fig. 6A The RLC bearer configuration IE 602 that can be used in the configuration of the MBS multicast service is illustrated. Figure 6B and Figure 6C 604 that can be used in the configuration of the MBS multicast service. It can be seen that the RLC bearer configuration IE 602 includes an MRB identity IE 606 that identifies the MRB as part of the configuration for the MBS multicast service (this is not about Figure 5 The case of configuration for MBS broadcast service as explained).

[0067] For some (e.g., contemplated) wireless communication systems, it should be understood that, as a baseline, the PTM configuration for RRC inactive mode provided in the RRC release message with "suspend configuration" for multicast MTCH (or MBS configuration information) may follow the form used for MBS broadcast configuration. In this case, the handling of existing MRBs for an MBS session upon / after a transition to RRC inactive mode may be undefined.

[0068] Note that with respect to the MBS configuration structure, the MBS broadcast configuration only supports full configuration. In addition, in various MBS broadcast service situations, the network may not provide explicit MRB ID configuration to the UE (e.g., as discussed elsewhere herein). Finally, in the present system, service continuity in multicast situations may be based on retaining / continuing to use an MRB at the UE with the same MRB ID as previously used, or at least an MRB ID that is otherwise explicitly identified and associated with the original MRB.

[0069] In this case, when the MBS broadcast configuration is used again in connection with the transition to RRC inactive mode in the case of the already proposed MBS multicast service, the result is that the operable multicast MRB configuration in RRC connected mode is different from that in RRC inactive mode, at least in that the configuration information in RRC inactive mode will not include MRB information accordingly. This may result in that MRB-based service continuity cannot be achieved in the case of a transition from RRC connected mode to RRC inactive mode.

[0070] With regard to parsing different multicast MRB configurations / structures between RRC inactive mode and RRC connected mode, the following two issues may be considered with regard to the RRC state transition from RRC connected mode to RRC inactive mode at the UE. The first issue relates to defining a way to handle the differences in multicast MRB configurations between RRC connected mode and RRC inactive mode. The second issue relates to a way to support MBS multicast service continuity during the transition from RRC connected mode to RRC inactive mode.

[0071] Various proposals are considered herein regarding these issues. In the first proposal, the UE is expected to maintain the PTM configuration for multicast reception in RRC connected mode and RRC inactive mode, respectively. In the second proposal, the MBS session for RRC inactive mode multicast reception is configured by RRC dedicated signaling. In this case, before / when the UE enters the RRC inactive mode, the network provides the UE with MBS session information for use in the RRC inactive mode. In the third proposal, MRB level or MBS session level service continuity during RRC state transitions can be supported. Note that MRB level service continuity can use the MRB ID provided in the inactive PTM configuration (as described herein).

[0072] Figure 7 A flow chart 702 illustrating a method for service continuity of data traffic of an MBS multicast service between a UE 704 and a network 706 according to embodiments herein. Preliminarily, the UE 704 may be in an RRC connected mode 708. While the UE is in the RRC connected mode 708, the network 706 may send an RRC reconfiguration message 710 to the UE 704 that provides the UE with an RRC connected mode PTM configuration. The UE may use the RRC connected mode PTM configuration to receive data traffic of the multicast MBS service while the UE is in the RRC connected mode 708.

[0073] The network 706 then sends an RRC release message 712 to the UE 704. As shown, the RRC release message 712 may include a configuration suspension indication. In response to the RRC release message 712, the UE 704 will enter an RRC inactive mode 714.

[0074] The RRC release message 712 includes an indication that the UE 704 will continue to receive the multicast data traffic for the MBS session while in the RRC inactive mode 714. In addition, the RRC release message 712 includes an RRC inactive mode PTM configuration that the UE will use to receive the multicast data traffic for the MBS session while the UE 704 is in the RRC inactive mode 714.

[0075] Upon receiving the RRC release message 712, the UE 704 reacts 716 in one or more ways. First, the UE 704 may release or store the RRC connected mode PTM configuration. In addition, the UE 704 applies the RRC inactive mode PTM configuration (including any MBS session information in the RRC inactive mode PTM configuration).

[0076] Finally, where the RRC inactive mode PTM configuration indicates an MRB ID identifying the same MRB of the RRC connected mode PTM configuration or an MRB ID that is different from but associated with the MRB of the RRC connected mode PTM configuration, the UE 704 may arrange to use the identified MRB (and, e.g., associated PDCP configuration and context) to receive multicast data traffic for the MBS session when the UE is in the RRC inactive mode 714. Consistent with the disclosure herein, this aspect may be utilized to provide multicast data traffic continuity for the MBS session at the MRB level, e.g., between the RRC connected mode and the RRC inactive mode.

[0077] After UE 704 is in RRC inactive mode 714, network 706 provides paging notification 718 to UE 704. As shown, paging notification 718 identifies the MBS session and instructs the UE to activate the RRC inactive mode PTM configuration for the MBS session so that UE 704 can receive multicast data traffic for the MBS session while UE 704 is in RRC inactive mode.

[0078] In response, the UE 704 begins 720 receiving multicast data traffic 722 for the MBS session using the RRC inactive mode PTM configuration.

[0079] At a later time, UE 704 sends an RRC resume request message 724 to network 706, as shown. After RRC resume request message 724, UE 704 may perform one or more actions 726. In at least some cases, after sending RRC resume request message 724, UE 704 continues to receive multicast data traffic 722 for the MBS session according to the RRC inactive mode PTM configuration. In addition, the UE may prepare to restore the RRC connected mode MBS configuration (e.g., RRC connected mode PTM configuration) that had been previously stored at the UE (e.g., as described with respect to how UE 704 reacts 716 in response to RRC release message 712).

[0080] The network 706 then responds to the RRC resume request message 724 by sending an RRC resume message 728 to the UE 704. As shown, in response to the RRC resume message 728, the UE re-enters the RRC connected mode 708. After re-entering the RRC connected mode 708, the UE receives multicast data traffic for the MBS session using the RRC connected mode PTM configuration (e.g., restoring a previous such connection from storage, or using a new such configuration provided, for example, in the RRC resume message 728).

[0081] Please note that Figure 7 The flowchart 702 is provided by way of example and not by way of limitation. As will be understood with reference to the material herein, various deviations from the flowchart 702 are contemplated that still remain within the scope of the present disclosure.

[0082] Implementation plan for PTM configuration maintenance

[0083] Various proposals regarding maintenance / continuity of PTM configuration for multicast data traffic of MBS sessions between RRC connected mode and RRC inactive mode are now discussed.

[0084] The discussion involves the use of both an RRC connected mode PTM configuration (which is used by the UE to receive multicast data traffic for an MBS session when the UE is in RRC connected mode) and an RRC inactive mode PTM configuration (which is used by the UE to receive multicast data traffic for an MBS session when the UE is in RRC inactive mode). In some cases, the UE may store (in an access stratum (AS) context) an RRC connected mode PTM configuration that was previously applicable when entering RRC inactive mode and switching to an RRC inactive mode PTM configuration. This may enable the UE to later resume use of the stored RRC connected mode PTM configuration (e.g., when re-entering RRC connected mode). In other cases, the UE may be configured to maintain only one PTM configuration, in which case the UE releases the RRC connected mode PTM configuration when receiving and applying the RRC inactive mode PTM configuration.

[0085] Fig. 8A A flow chart 802 illustrates a method for service continuity of data traffic for an MBS multicast service between a UE 804 and a network 806 according to embodiments herein.

[0086] Initially, UE 804 starts in RRC connected mode 808. Network 806 then sends RRC release message 810 to UE 804. As shown, the RRC release message 810 may include a configuration suspension indication. In response to the RRC release message 810, UE 804 will enter RRC inactive mode 812.

[0087] The RRC release message 810 includes an indication that the UE 804 will continue to receive the multicast data traffic for the MBS session while in the RRC inactive mode 812. In addition, the RRC release message 810 includes an RRC inactive mode PTM configuration that the UE will use to receive the multicast data traffic for the MBS session while the UE 804 is in the RRC inactive mode 812. As shown, the RRC inactive mode PTM configuration may identify itself as corresponding to the MBS session in question (note that the MBS session in question is in the RRC inactive mode 812). Fig. 8A denoted as “MBS Session #1” in the example).

[0088] Upon receiving the RRC release message 810, the UE 804 reacts 814 in one or more ways. First, the UE 804 may release or suspend the MBS session based on the reception of multicast data traffic for the MBS session using the RRC connected mode PTM configuration for the MBS session. Then, the UE 804 may release or store the RRC connected mode PTM configuration. Finally, the UE 704 applies the RRC inactive mode PTM configuration (including any MBS session information in the RRC inactive mode PTM configuration). This results in the establishment of the MBS session in question (again, "MBS Session #1") based on the reception of multicast data traffic for the MBS session using the RRC inactive mode PTM configuration for the MBS session (e.g., as received in the RRC release message 810).

[0089] Note that, in the event that the RRC inactive mode PTM configuration indicates an MRB ID that identifies the same MRB as the RRC connected mode PTM configuration or an MRB ID that is different from but associated with the MRB as the RRC connected mode PTM configuration, the UE 804 may arrange to use the identified MRB (and associated PDCP configuration and context) to receive multicast data traffic for the MBS session when the UE is in the RRC inactive mode 812.

[0090] After UE 804 is in RRC inactive mode 812, network 806 provides paging notification 816 to UE 804. As shown, paging notification 816 identifies the MBS session and instructs the UE to activate the RRC inactive mode PTM configuration for the MBS session so that UE 804 can receive multicast data traffic for the MBS session while UE 804 is in RRC inactive mode.

[0091] In response, the UE 804 begins 818 receiving data traffic for the MBS session using the RRC inactive mode PTM configuration.

[0092] It is contemplated that, in the event that the UE is unable / does not acquire the PTM configuration for the new RRC mode, the UE may continue to use the PTM configuration for the previous RRC mode for multicast reception (in the event that the multicast session is activated in the new RRC mode). For example, when the UE enters the RRC inactive mode and the network does not provide the RRC inactive mode PTM configuration in the RRC release message, the UE may continue to use the (e.g., in-use) RRC connected mode PTM configuration to receive multicast data traffic until the UE receives a new PTM configuration (e.g., receives the RRC inactive mode PTM configuration) via the MCCH channel or another further indication.

[0093] Figure 8BFlowchart 820 illustrates a method for service continuity of data traffic of an MBS multicast service between a UE 822 and a network 824 according to embodiments herein. Preliminarily, the UE 822 starts in RRC connected mode 826 .

[0094] The network 824 then sends an RRC release message 828 to the UE 822. As shown, the RRC release message 828 may include a configuration suspension indication. In response to the RRC release message 828, the UE 822 will enter an RRC inactive mode 830.

[0095] The RRC release message 828 includes an indication that the UE 822 will continue to receive the multicast data traffic for the MBS session while in the RRC inactive state. In addition, the RRC release message 810 includes an identifier of the MBS session (note that the MBS session in question is Figure 8B denoted as “MBS Session #1”).

[0096] However, please note that Figure 8B The RRC release message 828 does not include an RRC inactive mode PTM configuration to be used by the UE to receive multicast data traffic for the MBS session when the UE 804 is in the RRC inactive mode 812.

[0097] Upon receiving the RRC release message 828, the UE 822 reacts 832 in one or more ways. First, the UE 804 may store the applicable MBS session information. In addition, the UE is arranged to continue to use the RRC connected mode PTM configuration while in the RRC inactive mode 830.

[0098] Thus, as shown, after the UE 822 enters the RRC inactive mode 830, the UE 822 performs reception 834 of multicast data traffic for the MBS session using the RRC connected mode configuration (used when the UE was in the RRC connected mode 826).

[0099] Later, the network 824 sends an MBS multicast configuration message 836 to the UE 822 on the MCCH channel, indicating whether the UE's configuration for the MBS session (e.g., the RRC connected mode PTM configuration) is valid (should continue to be used) or should be deactivated. It should be noted that in other non-illustrated embodiments, it is expected that the MBS multicast configuration message 836 can be used to present a newly provided RRC inactive mode PTM configuration for continuing to receive multicast data traffic for the MBS session corresponding to the UE's RRC inactive mode (which may be the same as or different from the RRC connected mode PTM configuration).

[0100] In response to the MBS multicast configuration message 836, the UE 822 may respond 838 by storing or releasing the RRC connected mode PTM configuration (including, in some cases, any related MRB information). Additionally, the UE may maintain MBS session information for the MBS session at this time.

[0101] As described herein, in various cases, it should be understood that when a UE in an RRC inactive state initiates an RRC recovery procedure, the UE may continue to receive multicast data traffic using the RRC inactive mode PTM configuration before actually (re)entering RRC connected mode.

[0102] Implementation scheme for providing MBS session information for RRC inactive mode multicast data traffic reception

[0103] Fig. 9 Various options 902, 910, and 916 for transmitting MBS session information from a network to a UE according to embodiments discussed herein are illustrated.

[0104] In the first option 902 ("Option 1"), the network provides MBS session information 904 in the RRC inactive mode PTM configuration 906 in the RRC release message for the UE to use for multicast data traffic reception during the RRC inactive mode. As shown in the figure, according to this first option, the RRC inactive mode PTM configuration 906 may also include additional details 908 about the RRC inactive mode PTM configuration (e.g., in addition to the MBS session information 904).

[0105] In a second option 910 ("Option 2"), the network provides MBS session information 912 in an RRC connected mode PTM configuration 914 for use by the UE for multicast data traffic reception during RRC inactive mode. The RRC connected mode PTM configuration 914 may be delivered to the UE while the UE is in RRC connected mode and prior to any RRC release message instructing the UE to enter RRC inactive mode. Then, when the UE later receives an RRC release message, the UE may assume to use the MBS session information 912 as received in the RRC connected mode PTM configuration 914 (rather than, for example, expecting the RRC release message to provide the MBS session information). Note that in some embodiments according to the second option 910, when the network enables RRC inactive mode multicast data traffic reception, the UE may assume that all previously configured MBS sessions are used / available for such reception purposes.

[0106] The third option 916 ("Option 3") may be conceived in some manner as a hybrid or combination of the first option 902 and the second option 910. According to the third option 916, the network provides an MBS session information list 918 with one or more MBS session information sets in an RRC connected mode PTM configuration 920 (e.g., via RRC dedicated signaling). The network then sends an RRC release message with an RRC inactive mode PTM configuration 922 to the UE, the RRC inactive mode PTM configuration including an MBS session ID list 924. The MBS session ID list 924 identifies one or more MBS session information sets previously received in the MBS session information list 918 of the RRC connected mode PTM configuration, thereby identifying the MBS session information set used with respect to multicast data reception when the UE is in RRC inactive mode.

[0107] MBS session-level service continuity and MRB-level service continuity implementation plan

[0108] Various levels of service continuity for receiving multicast data traffic for an MBS session at a UE that may be used during a transition of the UE from an RRC connected mode to an RRC inactive mode are now discussed.

[0109] In the first option, such service continuity is maintained at the MBS session level (but not necessarily at the MRB level, for example). Accompanying the transition from RRC connected mode to RRC inactive mode, the UE uses the applicable MBS session information (regardless of how it is received) to maintain the SDAP entity for the MBS session between each of the RRC connected mode and the RRC inactive mode. Note that in this case, the associated PDCP entity and MRB / RLC / logical channel (LCH) may change across RRC mode transitions.

[0110] In a second option, such service continuity is maintained at the MRB level (in addition to the MBS session level). In this case, the SDAP entity is maintained as already described. Furthermore, in such a case, the MRB ID may be given in the RRC inactive mode PTM configuration provided to the UE (e.g., in the RRC release message). The UE then uses the identified MRB again to receive multicast data traffic according to the MBS session when in RRC inactive mode.

[0111] This represents a change within the various understandings that assume that the RRC inactive mode PTM configuration in MBS multicast services will follow the PTM configuration used by MBS broadcast services, since in such MBS broadcast service mechanisms the MRB ID for the corresponding broadcast data traffic is selected by the UE rather than indicated by the network.

[0112] According to the second option, in the RRC inactive mode PTM configuration, the network provides all associated MRB ID information. The UE will use this information to release the MRB for RRC connected mode and then set up (eg, reuse) the MRB for RRC inactive mode.

[0113] In the case where the MRB ID provided for RRC inactive mode in the RRC inactive mode PTM configuration is for an MRB previously used in accordance with the (previous) RRC connected mode PTM configuration, the UE may assume / maintain / reuse the previously existing PDCP context corresponding to that MRB for multicast data traffic reception between both RRC connected mode and RRC inactive mode.

[0114] Various cases may be considered within the framework of the second option (when the applicable MRB ID is the same between RRC connected mode and RRC inactive mode). In the first case, the UE assumes that an existing MRB of a previous RRC connected mode PTM configuration with the same MRB ID as indicated in the RRC inactive mode PTM configuration may continue / reuse to perform reception based on the existing context (e.g., as just discussed).

[0115] In the second case, when the applicable MRB ID is the same between RRC connected mode and RRC inactive mode, rather than the UE making assumptions as described, the network explicitly indicates to the UE whether to continue to use / reuse the existing MRB configuration and / or context. It can be noted that if there is no explicit indication under some UE configurations for this second case, then in at least some embodiments, the UE can fall back to making assumptions from the first case as described.

[0116] In the third case, where the applicable MRB ID is the same between RRC connected mode and RRC inactive mode, it is up to the UE specific implementation to decide whether to use / reuse the existing MRB to continue multicast data traffic reception or to establish a new MRB for multicast reception.

[0117] Fig.10A method 1000 of a UE according to an embodiment discussed herein is illustrated. The method 1000 includes receiving 1002 an RRC release message from a network while in an RRC connected mode, the RRC release message including an RRC inactive mode PTM configuration for the UE, the RRC inactive mode PTM configuration using an MBS session for receiving multicast data traffic from the network while the UE is in the RRC inactive mode. The method 1000 also includes entering 1004 an RRC inactive mode from the RRC connected mode in response to the RRC release message. The method 1000 also includes using 1006 the RRC inactive mode PTM configuration to receive multicast data traffic for the MBS session from the network while the UE is in the RRC inactive mode; wherein the same SDAP entity used to receive multicast data traffic for the MBS session when the UE is in the RRC connected mode is used to receive the multicast data traffic when the UE is in the RRC inactive mode.

[0118] In some embodiments of method 1000, the RRC inactive mode PTM configuration also includes a first MRB ID of a first MRB for an MBS session for receiving multicast data traffic when the UE is in RRC inactive mode. In some such embodiments, method 1000 also includes determining, based on the MRB ID, that the first MRB is used for receiving multicast data traffic from the network when the UE is in RRC connected mode; and reusing the first MRB as used in the RRC connected mode to receive multicast data traffic when the UE is in RRC inactive mode. In some such embodiments, the first MRB is used to receive multicast data traffic from the network when the UE is in RRC connected mode; and method 1000 also includes: receiving an indication from the network to reusing the first MRB as used in the RRC connected mode to receive multicast data traffic on the first MRB when the UE is in RRC inactive mode; and in response to the indication, reusing the first MRB as used in the RRC connected mode to receive multicast data traffic when the UE is in RRC inactive mode.

[0119] In some embodiments, method 1000 also includes receiving a paging message corresponding to the MBS session from the network while the UE is in the RRC inactive mode.

[0120] In some embodiments of method 1000, the RRC release message also includes an indication of receiving multicast data traffic while the UE is in the RRC inactive mode.

[0121] In some embodiments, method 1000 also includes storing an RRC connected mode PTM configuration, which is used to receive multicast data traffic when the UE is in RRC connected mode; re-entering the RRC connected mode from the RRC inactive mode; and after re-entering the RRC connected mode, using the stored RRC connected mode PTM configuration to receive multicast data traffic for the MBS session from the network.

[0122] In some embodiments of method 1000, the RRC inactive mode PTM configuration includes MBS session information for an MBS session.

[0123] In some embodiments, method 1000 further includes using MBS session information configured to the UE when the UE is in the RRC connected mode for the MBS session when the UE is in the RRC inactive mode.

[0124] In some embodiments, method 1000 also includes receiving MBS session information for each MBS session in an MBS session set including the MBS session from the network when the UE is in RRC connected mode, and wherein the RRC inactive mode PTM configuration includes an MBS session ID identifying the MBS session from the MBS session set.

[0125] Fig.11 A method 1100 of a RAN according to an embodiment discussed herein is illustrated. The method 1100 includes sending 1102 an RRC release message to a UE in an RRC connected mode, the RRC release message including an RRC inactive mode PTM configuration for the UE, the RRC inactive mode PTM configuration using an MBS session for receiving multicast data traffic from a network when the UE is in the RRC inactive mode. The method 1100 also includes transmitting 1104 the multicast data traffic for the MBS session to the UE when the UE is in the RRC inactive mode; wherein the same SDAP entity used to transmit the multicast data traffic for the MBS session when the UE is in the RRC connected mode is used to transmit the multicast data traffic when the UE is in the RRC inactive mode.

[0126] In some embodiments of the method 1100, the RRC inactive mode PTM configuration further includes a first MRB ID of a first MRB for an MBS session for receiving multicast data traffic when the UE is in the RRC inactive mode. In some such embodiments, the method 1100 further includes sending an indication to the UE to reuse the first MRB as used in the RRC connected mode to receive the multicast data traffic on the first MRB when the UE is in the RRC inactive mode.

[0127] In some embodiments, method 1100 also includes sending a paging message corresponding to the MBS session to the UE when the UE is in the RRC inactive mode.

[0128] In some embodiments of method 1100, the RRC release message also includes an indication to the UE to receive multicast data traffic while the UE is in the RRC inactive mode.

[0129] In some embodiments of method 1100, the RRC inactive mode PTM configuration includes MBS session information for the MBS session.

[0130] In some embodiments, method 1100 also includes sending MBS session information for the MBS session to the UE when the UE is in RRC connected mode.

[0131] In some embodiments, method 1100 also includes sending MBS session information for each MBS session in an MBS session set including the MBS session to the UE when the UE is in RRC connected mode, and wherein the RRC inactive mode PTM configuration includes an MBS session ID identifying the MBS session from the MBS session set.

[0132] Fig.12 A method 1200 of a UE according to an embodiment discussed herein is illustrated. The method 1200 includes using 1202 an RRC connected mode PTM configuration using an MBS session for receiving multicast data traffic from a network when the UE is in RRC connected mode. The method 1200 also includes receiving 1204 an RRC release message from the network when the UE is in RRC connected mode. The method 1200 also includes entering 1206 an RRC inactive mode from the RRC connected mode in response to the RRC release message. The method 1200 also includes using 1208 the RRC connected mode PTM configuration to receive multicast data traffic for the MBS session from the network when the UE is in RRC inactive mode.

[0133] In some implementations of method 1200, the same MRB is used in the MBS session to receive multicast data traffic for the MBS session when the UE is in each of the RRC connected mode and the RRC inactive mode.

[0134] In some embodiments, method 1200 also includes receiving an RRC inactive mode PTM configuration from a network, the RRC inactive mode PTM configuration using an MBS session when the UE is in RRC inactive mode; and using the RRC inactive mode PTM configuration to receive multicast data traffic for the MBS session from the network when the UE is in RRC inactive mode. In some such embodiments, method 1200 also includes storing an RRC connected mode PTM configuration; re-entering the RRC connected mode from the RRC inactive mode in response to an RRC resume message from the network; and after re-entering the RRC connected mode, receiving multicast data traffic for the MBS session from the network using the stored RRC connected mode PTM configuration. In some such embodiments, method 1200 also includes receiving an RRC resume message from the network when the UE is in RRC inactive mode; and after receiving the RRC resume message, using the RRC inactive mode PTM configuration to receive data traffic for the MBS session until the UE resumes the RRC connected mode.

[0135] Fig.13 A method 1300 of a RAN according to an embodiment discussed herein is illustrated. The method 1300 includes sending 1302 an RRC release message to a UE in RRC connected mode using an RRC connected mode PTM configuration using an MBS session for receiving multicast data traffic from a network when the UE is in RRC connected mode. The method 1300 also includes transmitting 1304 multicast data traffic for the MBS session to the UE when the UE is in RRC inactive mode.

[0136] In some implementations of method 1300, the same MRB is used in the MBS session to receive multicast data traffic for the MBS session when the UE is in each of the RRC connected mode and the RRC inactive mode.

[0137] In some embodiments, the method 1300 further includes sending an RRC inactive mode PTM configuration to the UE, the RRC inactive mode PTM configuration using the MBS session when the UE is in the RRC inactive mode.

[0138] Fig.14 An example architecture of a wireless communication system 1400 according to an embodiment disclosed herein is illustrated. The description provided below is for an example wireless communication system 1400 operating in conjunction with the LTE system standard and / or the 5G or NR system standard provided in the 3GPP technical specifications.

[0139] like Fig.14As shown, the wireless communication system 1400 includes UE 1402 and UE 1404 (however, any number of UEs may be used). In this example, UE 1402 and UE 1404 are illustrated as smartphones (e.g., handheld touch screen mobile computing devices capable of connecting to one or more cellular networks), but may also include any mobile or non-mobile computing device configured for wireless communication.

[0140] UE 1402 and UE 1404 may be configured to be communicatively coupled to RAN 1406. In an embodiment, RAN 1406 may be NG-RAN, E-UTRAN, etc. UE 1402 and UE 1404 utilize connections (or channels) (shown as connection 1408 and connection 1410, respectively) with RAN 1406, where each connection (or channel) includes a physical communication interface. RAN 1406 may include one or more base stations (such as base station 1412 and base station 1414) to implement connection 1408 and connection 1410.

[0141] In this example, connection 1408 and connection 1410 are air interfaces that enable such communicative coupling and may conform to the RAT used by RAN 1406 , such as, for example, LTE and / or NR.

[0142] In some embodiments, UE 1402 and UE 1404 may also directly exchange communication data via side link interface 1416. UE 1404 is shown as being configured to access an access point (shown as AP 1418) via connection 1420. By way of example, connection 1420 may include a local wireless connection, such as a connection conforming to any IEEE 802.11 protocol, wherein AP 1418 may include In this example, AP 1418 may not be connected to another network (eg, the Internet) through CN 1424.

[0143] In an embodiment, UE 1402 and UE 1404 may be configured to communicate with each other or with base station 1412 and / or base station 1414 over a multi-carrier communication channel using orthogonal frequency division multiplexing (OFDM) communication signals according to various communication techniques, such as, but not limited to, orthogonal frequency division multiple access (OFDMA) communication techniques (e.g., for downlink communication) or single carrier frequency division multiple access (SC-FDMA) communication techniques (e.g., for uplink and ProSe or sidelink communication), although the scope of the embodiment is not limited in this respect. OFDM signals may include multiple orthogonal subcarriers.

[0144] In some embodiments, all or part of base station 1412 or base station 1414 may be implemented as one or more software entities running on a server computer as part of a virtual network. In addition, or in other embodiments, base station 1412 or base station 1414 may be configured to communicate with each other via interface 1422. In an embodiment where wireless communication system 1400 is an LTE system (e.g., when CN 1424 is EPC), interface 1422 may be an X2 interface. The X2 interface may be defined between two or more base stations (e.g., two or more eNBs, etc.) connected to EPC and / or between two eNBs connected to EPC. In an embodiment where wireless communication system 1400 is an NR system (e.g., when CN 1424 is 5GC), interface 1422 may be an Xn interface. The Xn interface is defined between two or more base stations (e.g., two or more gNBs, etc.) connected to 5GC, between base station 1412 (e.g., gNB) and eNB connected to 5GC, and / or between two eNBs connected to 5GC (e.g., CN 1424).

[0145] RAN 1406 is shown as being communicatively coupled to CN 1424. CN 1424 may include one or more network elements 1426 configured to provide various data and telecommunication services to customers / subscribers (e.g., UE 1402 and users of UE 1404) connected to CN 1424 via RAN 1406. The components of CN 1424 may be implemented in one physical device or separate physical devices, including components for reading and executing instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium).

[0146] In an embodiment, CN 1424 may be an EPC, and RAN 1406 may be connected to CN 1424 via an S1 interface 1428. In an embodiment, S1 interface 1428 may be divided into two parts: an S1 user plane (S1-U) interface, which carries traffic data between base station 1412 or base station 1414 and a serving gateway (S-GW); and an S1-MME interface, which is a signaling interface between base station 1412 or base station 1414 and a mobility management entity (MME).

[0147] In an embodiment, CN 1424 may be a 5GC, and RAN 1406 may be connected to CN 1424 via an NG interface 1428. In an embodiment, NG interface 1428 may be divided into two parts: an NG user plane (NG-U) interface, which carries traffic data between base station 1412 or base station 1414 and a user plane function (UPF); and an S1 control plane (NG-C) interface, which is a signaling interface between base station 1412 or base station 1414 and an access and mobility management function (AMF).

[0148] In general, the application server 1430 may be an element that provides applications that use Internet Protocol (IP) bearer resources with the CN 1424 (e.g., packet-switched data services). The application server 1430 may also be configured to support one or more communication services (e.g., VoIP sessions, group communication sessions, etc.) for the UE 1402 and UE 1404 via the CN 1424. The application server 1430 may communicate with the CN 1424 via the IP communication interface 1432.

[0149] Fig.15 A system 1500 for performing signaling 1534 between a wireless device 1502 and a network device 1518 according to an embodiment disclosed herein is illustrated. The system 1500 may be part of a wireless communication system as described herein. The wireless device 1502 may be, for example, a UE of a wireless communication system. The network device 1518 may be, for example, a base station (e.g., an eNB or a gNB) of a wireless communication system.

[0150] The wireless device 1502 may include one or more processors 1504. The processor 1504 may execute instructions to perform various operations of the wireless device 1502, as described herein. The processor 1504 may include one or more baseband processors implemented using, for example, a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0151] The wireless device 1502 may include a memory 1506. The memory 1506 may be a non-transitory computer-readable storage medium that stores instructions 1508 (which may include, for example, instructions executed by the processor 1504). The instructions 1508 may also be referred to as program code or a computer program. The memory 1506 may also store data used by the processor 1504 and results computed by the processor.

[0152] The wireless device 1502 may include one or more transceivers 1510, which may include radio frequency (RF) transmitter circuitry and / or receiver circuitry that uses an antenna 1512 of the wireless device 1502 to facilitate signaling (e.g., signaling 1534) transmitted and / or received by the wireless device 1502 with other devices (e.g., network device 1518) in accordance with a corresponding RAT.

[0153] The wireless device 1502 may include one or more antennas 1512 (e.g., one, two, four, or more). For implementations with multiple antennas 1512, the wireless device 1502 may take full advantage of the spatial diversity of these multiple antennas 1512 to send and / or receive multiple different data streams on the same time-frequency resources. This approach may be referred to as, for example, a multiple-input multiple-output (MIMO) approach (referring to multiple antennas used on the transmitting device and the receiving device side to implement this aspect, respectively). MIMO transmission by the wireless device 1502 may be implemented based on precoding (or digital beamforming) applied to the wireless device 1502, which multiplexes data streams between the antennas 1512 based on known or assumed channel characteristics, so that each data stream is received with appropriate signal strength relative to other streams and at a desired location in the spatial domain (e.g., the location of the receiver associated with the data stream). Certain implementations may use a single-user MIMO (SU-MIMO) approach (where data streams are all directed to a single receiver) and / or a multi-user MIMO (MU-MIMO) approach (where individual data streams may be directed to individual (different) receivers at different locations in the spatial domain).

[0154] In certain embodiments with multiple antennas, the wireless device 1502 may implement analog beamforming techniques whereby the phases of the signals transmitted by the antennas 1512 are adjusted relative to each other so that the (joint) transmissions of the antennas 1512 are directional (this is sometimes referred to as beam steering).

[0155] The wireless device 1502 may include one or more interfaces 1514. The interfaces 1514 may be used to provide input to or output from the wireless device 1502. For example, a wireless device 1502 that is a UE may include an interface 1514, such as a microphone, a speaker, a touch screen, buttons, etc., to allow a user of the UE to provide input and / or output to the UE. Other interfaces of such a UE may be composed of transmitters, receivers, and other circuits that allow the UE to communicate with other devices (e.g., in addition to the transceiver 1510 / antenna 1512 described above), and may communicate according to known protocols (e.g., etc.) to perform the operation.

[0156] The wireless device 1502 may include an MBS module 1516. The MBS module 1516 may be implemented via hardware, software, or a combination thereof. For example, the MBS module 1516 may be implemented as a processor, circuit, and / or instruction 1508 stored in the memory 1506 and executed by the processor 1504. In some examples, the MBS module 1516 may be integrated within the processor 1504 and / or the transceiver 1510. For example, the MBS module 1516 may be implemented by a combination of software components (e.g., executed by a DSP or a general purpose processor) and hardware components (e.g., logic gates and circuits) within the processor 1504 or the transceiver 1510.

[0157] The MBS module 1516 may be used in various aspects of the present disclosure, for example, Figures 1A to 13 MBS module 1516 may be configured, for example, to cause wireless device 1502 to: receive an RRC release message from a network (e.g., from a network device 1518 that is a base station of the network) while in RRC connected mode, the RRC release message including an RRC inactive mode PTM configuration for wireless device 1502, the RRC inactive mode PTM configuration using an MBS session for receiving multicast data traffic from the network while wireless device 1502 is in RRC inactive mode; enter RRC inactive mode from RRC connected mode in response to the RRC release message; and use the RRC inactive mode PTM configuration to receive multicast data traffic for the MBS session from the network while wireless device 1502 is in RRC inactive mode; wherein the same SDAP entity used to receive multicast data traffic for the MBS session when the UE is in RRC connected mode is used to receive multicast data traffic when the UE is in RRC inactive mode. The MBS module 1516 can be configured to, for example, cause the wireless device 1502 to: use an RRC connected mode PTM configuration that uses an MBS session for receiving multicast data traffic from a network (e.g., from a network device 1518 that is a base station of the network) when the UE is in RRC connected mode; receive an RRC release message from the network when the wireless device 1502 is in RRC connected mode; enter an RRC inactive mode from the RRC connected mode in response to the RRC release message; and use the RRC connected mode PTM configuration to receive multicast data traffic for the MBS session from the network when the wireless device 1502 is in RRC inactive mode.

[0158] The network device 1518 may include one or more processors 1520. The processor 1520 may execute instructions to perform various operations of the network device 1518, as described herein. The processor 1520 may include one or more baseband processors implemented using, for example, a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0159] The network device 1518 may include a memory 1522. The memory 1522 may be a non-transitory computer-readable storage medium that stores instructions 1524 (which may include, for example, instructions executed by the processor 1520). The instructions 1524 may also be referred to as program code or a computer program. The memory 1522 may also store data used by the processor 1520 and results calculated by the processor.

[0160] The network device 1518 may include one or more transceivers 1526, which may include RF transmitter circuitry and / or receiver circuitry that uses an antenna 1528 of the network device 1518 to facilitate signaling (e.g., signaling 1534) transmitted and / or received by the network device 1518 with other devices (e.g., wireless device 1502) according to a corresponding RAT.

[0161] The network device 1518 may include one or more antennas 1528 (e.g., one, two, four, or more). In an embodiment with multiple antennas 1528, the network device 1518 may perform MIMO, digital beamforming, analog beamforming, beam steering, etc. as described above.

[0162] The network device 1518 may include one or more interfaces 1530. The interface 1530 may be used to provide input to or output from the network device 1518. For example, the network device 1518 as a base station may include an interface 1530 composed of a transmitter, a receiver and other circuits (e.g., in addition to the transceiver 1526 / antenna 1528 described above), which enables the base station to communicate with other equipment in the core network and / or enables the base station to communicate with external networks, computers, databases, etc., for the purpose of performing operations, management and maintenance of the base station or other equipment operably connected thereto.

[0163] The network device 1518 may include an MBS module 1532. The MBS module 1532 may be implemented via hardware, software, or a combination thereof. For example, the MBS module 1532 may be implemented as a processor, circuit, and / or instruction 1524 stored in the memory 1522 and executed by the processor 1520. In some examples, the MBS module 1532 may be integrated within the processor 1520 and / or the transceiver 1526. For example, the MBS module 1532 may be implemented by a combination of software components (e.g., executed by a DSP or general purpose processor) and hardware components (e.g., logic gates and circuits) within the processor 1520 or the transceiver 1526.

[0164] The MBS module 1532 may be used in various aspects of the present disclosure, for example, Figures 1A to 13 The MBS module 1532 may be configured to cause the network device 1518 to transmit an RRC release message to a UE (e.g., wireless device 1502) in RRC connected mode, the RRC release message including an RRC inactive mode PTM configuration for the UE, the RRC inactive mode PTM configuration using an MBS session for receiving multicast data traffic from the network when the UE is in RRC inactive mode, and transmitting multicast data traffic for the MBS session to the UE when the UE is in RRC inactive mode; wherein the same SDAP entity used to transmit multicast data traffic for the MBS session when the UE is in RRC connected mode is used to transmit multicast data traffic when the UE is in RRC inactive mode. The MBS module 1532 can be configured to cause the network device 1518 to: send an RRC release message to a UE (e.g., wireless device 1502) in RRC connected mode using an RRC connected mode PTM configuration, wherein the RRC connected mode PTM configuration uses an MBS session for receiving multicast data traffic from the network when the UE is in RRC connected mode; and transmit multicast data traffic for the MBS session to the UE when the UE is in RRC inactive mode.

[0165] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of any of the methods 1000 and / or 1200. For example, the apparatus may be an apparatus of a UE (such as the wireless device 1502 as a UE, as described herein).

[0166] Embodiments contemplated herein include one or more non-transitory computer-readable media including instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of any of method 1000 and / or method 1200. For example, the non-transitory computer-readable medium may be a memory of a UE (such as memory 1506 of wireless device 1502 as a UE, as described herein).

[0167] Embodiments contemplated herein include an apparatus comprising logical components, modules, or circuits for performing one or more elements of any of the method 1000 and / or the method 1200. For example, the apparatus may be an apparatus of a UE (such as the wireless device 1502 as a UE, as described herein).

[0168] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform one or more elements of any of the methods 1000 and / or 1200. For example, the apparatus may be an apparatus of a UE (such as the wireless device 1502 as a UE, as described herein).

[0169] Embodiments contemplated herein include a signal as described in or associated with one or more elements of any of method 1000 and / or method 1200 .

[0170] Embodiments contemplated herein include a computer program or computer program product including instructions, wherein execution of the program by a processor causes the processor to perform one or more elements of any of the methods 1000 and / or 1200. The processor may be a processor of a UE (such as the processor 1504 of the wireless device 1502 as a UE, as described herein). For example, these instructions may be located in the processor and / or on a memory of the UE (such as the memory 1506 of the wireless device 1502 as a UE, as described herein).

[0171] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of any of method 1100 and / or method 1300. For example, the apparatus may be an apparatus of a base station (such as network device 1518 as a base station, as described herein).

[0172] Embodiments contemplated herein include one or more non-transitory computer-readable media including instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of any of method 1100 and / or method 1300. For example, the non-transitory computer-readable medium may be a memory of a base station (such as memory 1522 of network device 1518 acting as a base station, as described herein).

[0173] Embodiments contemplated herein include an apparatus comprising logical components, modules, or circuits for performing one or more elements of any of the method 1100 and / or the method 1300. For example, the apparatus may be an apparatus of a base station (such as the network device 1518 as a base station, as described herein).

[0174] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform one or more elements of any of the method 1100 and / or the method 1300. For example, the apparatus may be an apparatus of a base station (such as the network device 1518 as a base station, as described herein).

[0175] Embodiments contemplated herein include a signal as described in or associated with one or more elements of any of method 1100 and / or method 1300 .

[0176] Embodiments contemplated herein include a computer program or computer program product including instructions, wherein execution of the program by a processing element causes the processing element to perform one or more elements of any of the methods 1100 and / or 1300. The processor may be a processor of a base station (such as the processor 1520 of the network device 1518 as a base station, as described herein). For example, the instructions may be located in the processor and / or on a memory of the base station (such as the memory 1522 of the network device 1518 as a base station, as described herein).

[0177] For one or more embodiments, at least one of the components shown in one or more of the foregoing figures may be configured to perform one or more operations, techniques, processes and / or methods as described herein. For example, the baseband processor described herein in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the examples described herein. For another example, the circuits associated with the UE, base station, network element, etc. described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the examples shown herein.

[0178] Unless otherwise expressly stated, any of the above embodiments may be combined with any other embodiment (or combination of embodiments). The foregoing description of one or more specific implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise form disclosed. In view of the above teachings, modifications and variations are possible or can be obtained from the practice of various embodiments.

[0179] Embodiments and implementations of the systems and methods described herein may include various operations that may be embodied in machine executable instructions to be executed by a computer system. A computer system may include one or more general or special purpose computers (or other electronic devices). A computer system may include hardware components that include specific logic components for performing operations, or may include a combination of hardware, software, and / or firmware.

[0180] It should be appreciated that the systems described herein include descriptions of specific embodiments. These embodiments may be combined into a single system, partially incorporated into other systems, separated into multiple systems, or otherwise divided or combined. In addition, it is contemplated that parameters, attributes, aspects, etc. of one embodiment may be used in another embodiment. For clarity, these parameters, attributes, aspects, etc. are described only in one or more embodiments, and it should be appreciated that unless otherwise stated herein, these parameters, attributes, aspects, etc. may be combined with or substituted for parameters, attributes, aspects, etc. of another embodiment.

[0181] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users.

[0182] Although the foregoing has been described in considerable detail for the sake of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles of the invention. It should be noted that there are many alternative ways to implement both the processes and the apparatus described herein. Therefore, the embodiments of the present invention are to be regarded as illustrative rather than restrictive, and the specification is not limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Claims

1. A method of a user equipment (UE), the method comprising: receiving, while in a radio resource control (RRC) connected mode, a RRC release message from a network, the RRC release message including an RRC inactive mode point-to-multipoint (PTM) configuration for the UE, the RRC inactive mode PTM configuration using a multicast broadcast service (MBS) session for receiving multicast data traffic from the network while the UE is in the RRC inactive mode; In response to the RRC release message, entering the RRC inactive mode from the RRC connected mode; as well as using the RRC inactive mode PTM configuration to receive the multicast data traffic for the MBS session from the network when the UE is in the RRC inactive mode; The same Service Data Adaptation Protocol (SDAP) entity used to receive the multicast data traffic for the MBS session when the UE is in the RRC connected mode is used to receive the multicast data traffic when the UE is in the RRC inactive mode.

2. The method of claim 1, wherein the RRC inactive mode PTM configuration further comprises a first MRBID of a first MBS Radio Bearer (MRB) of the MBS session for receiving the multicast data traffic when the UE is in the RRC inactive mode.

3. The method according to claim 2, further comprising: determining, based on the MRB ID, the first MRB for receiving the multicast data traffic from the network when the UE is in the RRC connected mode; as well as The first MRB as used in the RRC connected mode is reused to receive the multicast data traffic when the UE is in the RRC inactive mode.

4. The method of claim 2, wherein the first MRB is used to receive the multicast data traffic from the network when the UE is in the RRC connected mode; And the method also includes: receiving, from the network, an indication to reuse the first MRB as used in the RRC connected mode to receive the multicast data traffic on the first MRB when the UE is in the RRC inactive mode; as well as In response to the indication, the first MRB as used in the RRC connected mode is reused to receive the multicast data traffic when the UE is in the RRC inactive mode.

5. The method according to claim 1, further comprising: A paging message corresponding to the MBS session is received from the network while the UE is in the RRC inactive mode.

6. The method of claim 1, wherein the RRC release message further includes an indication of receiving the multicast data traffic while the UE is in the RRC inactive mode.

7. The method according to claim 1, further comprising: storing an RRC connected mode PTM configuration, the RRC connected mode PTM configuration being used to receive the multicast data traffic when the UE is in the RRC connected mode; re-entering the RRC connected mode from the RRC inactive mode; as well as After re-entering the RRC connected mode, the multicast data traffic for the MBS session is received from the network using the RRC connected mode PTM configuration.

8. The method of claim 1, wherein the RRC inactive mode PTM configuration includes MBS session information for the MBS session.

9. The method according to claim 1, further comprising using MBS session information configured to the UE when the UE is in the RRC connected mode for the MBS session when the UE is in the RRC inactive mode.

10. The method of claim 1 , further comprising, when the UE is in the RRC connected mode, receiving, from the network, MBS session information for each MBS session in an MBS session set including the MBS session, and wherein the RRC inactive mode PTM configuration comprises an MBS session ID, the MBS session ID identifying the MBS session from the MBS session set.

11. A method of a Radio Access Network (RAN), the method comprising: sending a RRC release message to a user equipment (UE) in a radio resource control (RRC) connected mode, the RRC release message including an RRC inactive mode point-to-multipoint (PTM) configuration for the UE, the RRC inactive mode PTM configuration using a multicast broadcast service (MBS) session for receiving multicast data traffic from the network when the UE is in the RRC inactive mode, transmitting the multicast data traffic of the MBS session to the UE when the UE is in the RRC inactive mode; The same Service Data Adaptation Protocol (SDAP) entity used to transmit the multicast data traffic of the MBS session when the UE is in the RRC connected mode is used to transmit the multicast data traffic when the UE is in the RRC inactive mode.

12. The method of claim 11, wherein the RRC inactive mode PTM configuration further comprises a first MRB identifier (ID) of a first MBS radio bearer (MRB) of the MBS session for receiving the multicast data traffic when the UE is in the RRC inactive mode.

13. The method of claim 12, further comprising sending an indication to the UE to reuse the first MRB as used in the RRC connected mode to receive the multicast data traffic on the first MRB when the UE is in the RRC inactive mode.

14. The method according to claim 11, further comprising sending a paging message corresponding to the MBS session to the UE when the UE is in the RRC inactive mode.

15. The method of claim 11, wherein the RRC release message further includes an indication for the UE to receive the multicast data traffic while the UE is in the RRC inactive mode.

16. The method of claim 11, wherein the RRC inactive mode PTM configuration includes MBS session information for the MBS session. 17 . The method of claim 11 , further comprising sending MBS session information for the MBS session to the UE when the UE is in the RRC connected mode.

18. The method of claim 11, further comprising, when the UE is in the RRC connected mode, sending MBS session information for each MBS session in an MBS session set including the MBS session to the UE, and wherein the RRC inactive mode PTM configuration includes an MBS session ID, the MBS session ID identifying the MBS session from the MBS session set.

19. A method of a user equipment (UE), the method comprising: using a radio resource control (RRC) connected mode point-to-multipoint (PTM) configuration, the RRC connected mode PTM configuration using a multicast broadcast service (MBS) session for receiving multicast data traffic from a network when the UE is in RRC connected mode; When the UE is in the RRC connected mode, receiving an RRC release message from the network; In response to the RRC release message, entering an RRC inactive mode from the RRC connected mode; as well as The RRC connected mode PTM configuration is used to receive the multicast data traffic for the MBS session from the network when the UE is in the RRC inactive mode.

20. The method of claim 19, wherein a same MBS Radio Bearer (MRB) is used in the MBS session to receive the multicast data traffic of the MBS session when the UE is in each of the RRC connected mode and the RRC inactive mode.

21. The method according to claim 19, further comprising: receiving an RRC inactive mode PTM configuration from the network, the RRC inactive mode PTM configuration using the MBS session when the UE is in the RRC inactive mode; as well as The RRC inactive mode PTM configuration is used to receive the multicast data traffic for the MBS session from the network when the UE is in the RRC inactive mode.

22. The method according to claim 21, further comprising: Storing the RRC connected mode PTM configuration; re-entering the RRC connected mode from the RRC inactive mode in response to an RRC resume message from the network; as well as After re-entering the RRC connected mode, the multicast data traffic for the MBS session is received from the network using the RRC connected mode PTM configuration.

23. The method according to claim 21, further comprising: When the UE is in the RRC inactive mode, receiving an RRC resume message from the network; as well as After receiving the RRC resume message, the data traffic of the MBS session is received using the RRC inactive mode PTM configuration until the UE resumes the RRC connected mode.

24. A method of a Radio Access Network (RAN), the method comprising: sending an RRC release message to a user equipment (UE) in a radio resource control (RRC) connected mode point-to-multipoint (PTM) configuration using a multicast broadcast service (MBS) session for receiving multicast data traffic from a network while the UE is in the RRC connected mode; as well as The multicast data traffic of the MBS session is transmitted to the UE while the UE is in the RRC inactive mode.

25. The method of claim 24, wherein a same MBS Radio Bearer (MRB) is used in the MBS session to receive the multicast data traffic of the MBS session when the UE is in each of the RRC connected mode and the RRC inactive mode.

26. The method of claim 24, further comprising sending an RRC inactive mode PTM configuration to the UE, the RRC inactive mode PTM configuration using the MBS session when the UE is in the RRC inactive mode.

27. An apparatus comprising means for performing the method according to any one of claims 1 to 26.

28. A computer-readable medium comprising instructions which, when executed by one or more processors of an electronic device, cause the electronic device to perform the method according to any one of claims 1 to 26.

29. An apparatus comprising logic components, modules or circuits for performing the method according to any one of claims 1 to 26.

30. A baseband processor for a user equipment (UE), the baseband processor being configured to cause the UE to perform one or more elements of any one of claims 1 to 10 or 19 to 23.

31. A baseband processor for a base station of a radio access network (RAN), the baseband processor being configured to cause the base station to perform one or more elements of any one of claims 11 to 18 or claims 24 to 26.

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