Method executed by user equipment, and user equipment

Abstract

Provided in the present invention are a method executed by a user equipment, and a user equipment. The method executed by the user equipment (UE) comprises: a UE receiving an RRC release message from a base station; and executing a corresponding operation when the RRC release message includes a first instruction identifier, and when the first instruction identifier is configured to instruct the UE to maintain a small data transmission (SDT) process or instruct an MBS multicast session to be activated or instruct the UE not to execute an operation executed when entering RRC_INACTIVE or RRC_IDLE or instruct the UE to detect a multicast MCCH-RNTI or instruct the UE to detect a G-RNTI of the MBS multicast session.

Description

Method performed by user equipment and user equipment Technical Field

[0001] The present invention relates to the technical field of wireless communications, and more particularly, to a method executed by a user equipment and the user equipment. Background Art

[0002] A study project (SI) on improving the 5G multicast broadcast service architecture (see SP-190625) has been approved. One of the objectives of this SI (referred to as Objective A) is to support universal MBS services in 5GS. Use cases that could benefit from this feature include (but are not limited to) public safety, vehicle-to-everything (V2X) applications, transparent IPv4 / IPv6 multicast transmission, IPTV, wireless software delivery, group communications, and IoT applications. Accordingly, at the 3rd Generation Partnership Project (3GPP) RAN#86 plenary meeting, a work item on NR multicast and broadcast service (NR MBS) was proposed and approved (see non-patent document RP-193248: New WID: NR Multicast and Broadcast Service). This work item aims to provide support for Objective A in the RAN. The objectives of this work item have been largely achieved, and the relevant solutions are described in 3GPP Release 17 technical documents such as TS 38.300-h70, TS 38.331-h70, and TS 38.321-h70. At the 3GPP RAN#94 plenary meeting, a work item titled Enhanced NR Multicast and Broadcast Services was approved (see non-patent literature: RP-213568: New WID: Enhancements of NR Multicast and Broadcast Services). This work item aims to further enhance MBS Multicast and Broadcast Services in Release 17, with one of its goals being to support user equipment receiving MBS multicast services / sessions even when RRC is not active.

[0003] The present invention discusses issues related to RAN supporting user equipment to receive MBS multicast services / sessions in an RRC inactive state. Summary of the Invention

[0004] In order to solve at least part of the above problems, the present invention provides a method performed by a user equipment and the user equipment.

[0005] According to a first aspect of the present invention, a method performed by a user equipment (UE) is provided, comprising: the UE receiving an RRC release message from a base station; and, when the RRC release message includes a first indication identifier, the first indication identifier being used to instruct the UE to maintain a small data transmission (SDT) process, or to indicate that an MBS multicast session is activated, or to instruct the UE not to perform an operation performed by entering RRC_INACTIVE or RRC_IDLE, or to instruct the UE to detect a multicast MCCH-RNTI, or to instruct the UE to detect a G-RNTI of a multicast MBS session, performing at least one of the following operations:

[0006] Operation 1-1a: Apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field included in the RRC release message;

[0007] Operation 1-1b: If the RRC release message includes the multicastConfigInactive field, apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field; and / or if the RRC release message does not include the multicastConfigInactive field, obtain the MBSMulticastConfiguration message on the multicast MCCH;

[0008] Operation 1-1c: If the RRC release message includes a multicastConfigInactive field and at least one MBS multicast session indicated by a TMGI included therein is not instructed to stop detecting the corresponding G-RNTI and the PTM configurations of all MBS multicast sessions not instructed to stop detecting the G-RNTI are included in the multicastConfigInactive field, apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field; and / or if the RRC release message does not include a multicastConfigInactive field or there is an MBS multicast session for which the PTM configuration is not instructed to stop detecting the G-RNTI and is not included in the multicastConfigInactive field, obtain an MBSMulticastConfiguration message on the multicast MCCH;

[0009] Operation 1-1d: If the RRC release message includes the multicastConfigInactive field and / or the inactivePTM-Config field, apply the PTM configuration or apply the PTM configuration included in the inactivePTM-Config field; and / or if the RRC release message does not include the inactivePTM-Config field, obtain the MBSMulticastConfiguration message on the multicast MCCH;

[0010] Operation 1-1e: Detect the multicast MCCH-RNTI, or detect the G-RNTI of all joined MBS multicast sessions;

[0011] Operation 1-1f: The first indicator includes a G-RNTI list, and the UE detects the G-RNTI included in the first indicator;

[0012] Operation 1-1g: The process ends.

[0013] In the above method involved in the first aspect of the present invention, the RRC release message may also include a suspendConfig field, and the suspendConfig field includes the first indication identifier.

[0014] In the above method involved in the first aspect of the present invention, when the RRC release message does not include the first indication identifier, the UE may perform at least one of the following operations:

[0015] Action 1-1A: Reset MAC and / or release the default MAC cell group configuration;

[0016] Operation 1-1B: Suspend all SRBs and DRBs except SRB0 and broadcast MRB.

[0017] Action 1-1C: Suspend all multicast MRBs associated to multicast sessions that are not configured for RRC_INATIVE reception;

[0018] Action 1-1D: Enter RRC_INACTIVE and / or perform cell selection;

[0019] Operation 1-1E: Perform the operations performed when entering RRC_IDLE.

[0020] In the above method involved in the first aspect of the present invention, when the multicastConfig Inactive field is included in the suspendConfig, the first indication flag may be included in the suspendConfig.

[0021] Furthermore, according to a second aspect of the present invention, a method performed by a user equipment (UE) is provided, comprising: the UE receiving an RRC release message from a base station; and, when the RRC release message includes a first indication identifier, the first indication identifier being used to instruct the UE to terminate a small data transmission (SDT) process or to indicate that the RRC release message is not for MBS multicast activation, performing at least one of the following operations:

[0022] Action 1-1A: Reset MAC and / or release the default MAC cell group configuration;

[0023] Operation 1-1B: Suspend all SRBs and DRBs except SRB0 and broadcast MRB.

[0024] Action 1-1C: Suspend all multicast MRBs associated to multicast sessions that are not configured for RRC_INATIVE reception;

[0025] Action 1-1D: Enter RRC_INACTIVE and / or perform cell selection;

[0026] Operation 1-1E: Perform the operations performed when entering RRC_IDLE.

[0027] In the method involved in the second aspect of the present invention, at least one of the following operations may be performed when the RRC release message does not include the first indication identifier:

[0028] Operation 1-1a: Apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field included in the RRC release message;

[0029] Operation 1-1b: If the RRC release message includes the multicastConfigInactive field, apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field; and / or if the RRC release message does not include the multicastConfigInactive field, obtain the MBSMulticastConfiguration message on the multicast MCCH;

[0030] Operation 1-1c: If the RRC release message includes a multicastConfigInactive field and at least one MBS multicast session indicated by a TMGI included therein is not instructed to stop detecting the corresponding G-RNTI and the PTM configurations of all MBS multicast sessions not instructed to stop detecting the G-RNTI are included in the multicastConfigInactive field, apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field; and / or if the RRC release message does not include a multicastConfigInactive field or there is an MBS multicast session for which the PTM configuration is not instructed to stop detecting the G-RNTI and is not included in the multicastConfigInactive field, obtain an MBSMulticastConfiguration message on the multicast MCCH;

[0031] Operation 1-1d: If the RRC release message includes the multicastConfigInactive field and / or the inactivePTM-Config field, apply the PTM configuration or apply the PTM configuration included in the inactivePTM-Config field; and / or if the RRC release message does not include the inactivePTM-Config field, obtain the MBSMulticastConfiguration message on the multicast MCCH;

[0032] Operation 1-1e: Detect the multicast MCCH-RNTI, or detect the G-RNTI of all joined MBS multicast sessions;

[0033] Operation 1-1f: The first indicator includes a G-RNTI list, and the UE detects the G-RNTI included in the first indicator;

[0034] Operation 1-1g: The process ends.

[0035] In addition, according to a third aspect of the present invention, a method performed by a user equipment UE is provided, comprising: the UE initiating an RRC connection recovery procedure; detecting a multicast MCCH-RNTI when a condition for initiating small data transmission SDT is met and the UE is configured to receive MBS multicast in RRC_INACTIVE and / or the UE is not detecting a multicast MCCH-RNTI.

[0036] The method involved in the third aspect of the present invention may also include: the UE receiving an RRC release message from the base station; and stopping detecting the multicast MCCH-RNTI when the RRC release message does not include the multicastConfigInactive field.

[0037] The method involved in the third aspect of the present invention may also include: the UE receiving an RRC release message from the base station; and if the RRC release message does not include the multicastConfigInactive field and the UE does not detect any G-RNTI, stopping detecting the multicast MCCH-RNTI.

[0038] In addition, according to a fourth aspect of the present invention, there is provided a user equipment, comprising: a processor; and a memory storing instructions, wherein the instructions execute the above method when executed by the processor.

[0039] Effects of the Invention

[0040] According to the method performed by the user equipment and the user equipment involved in the present invention, the user equipment UE can normally obtain the activation indication of the MBS multicast session during the SDT process. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and other features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0042] FIG1 is a schematic flow chart showing a method executed by a user equipment in embodiment 1 of the present invention.

[0043] FIG2 is a schematic flow chart showing a method executed by a user equipment in embodiment 2 of the present invention.

[0044] FIG3 is a schematic flow chart illustrating an embodiment of operations performed by a UE upon receiving an RRC release message.

[0045] FIG4 is a block diagram showing a user equipment UE according to the present invention. DETAILED DESCRIPTION

[0046] The following describes some of the terms involved in the present invention. For their specific meanings, please refer to the latest 3GPP documents, such as TS38.300-i00, TS38.321-i00, TS38.323-i00, and TS38.331-i00 (partial content of version i00 is still under discussion). Furthermore, the embodiments of the present invention are described using broadcast / multicast services as an example. However, the embodiments of the present invention are not limited to broadcast / multicast services and can also be applied to other application scenarios.

[0047] UE: User Equipment.

[0048] RRC: Radio Resource Control.

[0049] RRC_CONNECTED: RRC connected state.

[0050] RRC_INACTIVE: RRC inactive state.

[0051] RRC_IDLE: RRC idle state.

[0052] RAN: Radio Access Network.

[0053] NR: New RAT, new radio access technology.

[0054] MBS: Multicast / Broadcast Services. Multicast can also be called multicast.

[0055] AS: Access Stratum, access layer or access layer.

[0056] NAS: Non Access Stratum, non-access layer or non-access layer.

[0057] RB: Radio Bearer. DRB is a data radio bearer.

[0058] MBS Radio Bearer (MRB): A radio bearer configured for MBS delivery. MRBs are classified into multicast MRBs and broadcast MRBs. A multicast MRB is a radio bearer configured for MBS multicast transmission, while a broadcast MRB is a radio bearer configured for MBS broadcast transmission.

[0059] TMGI: Temporary Mobile Group Identity, used to identify an MBS session.

[0060] RNTI: Radio Network Temporary Identifier, wireless network temporary identifier.

[0061] PTM (Point to Multipoint) is a method for delivering MBS services. In PTM, the gNB delivers a single copy of MBS data packets to a group of UEs. UEs use a G-RNTI or G-CS-RNTI to receive PTM transmissions. For example, the gNB uses the G-RNTI-based group-common physical downlink control channel (PDCCH) to schedule the same G-RNTI-based group-common physical downlink shared channel (PDSCH).

[0062] PTP (Point to Point) is a delivery method for MBS services. In PTP, the gNB individually delivers separate copies of MBS data packets to each UE independently. For example, the base station schedules the UE-specific PDCCH scrambled with the UE-specific RNTI and the UE-specific PDSCH scrambled with the same UE-specific RNTI.

[0063] PCell: Primary Cell, MCG cell, operates on the primary frequency, in which the UE performs the initial connection establishment process or initiates the connection re-establishment process.

[0064] SCell: Secondary Cell. For UEs configured with carrier aggregation, an SCell is a cell that provides additional radio resources on top of a special cell. For dual connectivity, the term special cell refers to the PCell of an MCG or the PSCell of an SCG. In carrier aggregation, the term special cell refers to the PCell. For dual connectivity, the PSCell is the SCG cell in which the UE performs random access during the synchronous reconfiguration procedure.

[0065] G-RNTI: Group RNTI, group RNTI, used to scramble the scheduling and transmission of PTM for one or more MBS multicast services.

[0066] G-CS-RNTI: Group configuration scheduling RNTI, used to scramble the semi-static scheduling SPS group common physical downlink shared channel PDSCH of one or more MBS multicast services and activate / deactivate the SPS group common PDSCH.

[0067] MTCH: MBS Traffic Channel, MBS traffic channel, is a PTM downlink channel used to transmit MBS data of a multicast session or broadcast session from the network to the UE. Unless otherwise specified, the MTCH involved in the embodiments of the present disclosure refers to the multicast MTCH used to transmit MBS multicast sessions.

[0068] MCCH: MBS Control Channel, MBS control channel, is a PTM downlink channel used for transmitting MBS broadcast or MBS multicast control information associated to one or several MTCH(s) from the network to the UE. MCCH includes broadcast MCCH and multicast MCCH.

[0069] The RRC recovery request message RRCResumeRequest or RRCResumeRequest1 is used to request the resumption of a suspended RRC connection or to perform a RAN-based notification area RNA update. When the UE initiates an RRC connection resumption request, if the SIB1 contains the useFullResumeID field, the RRCResumeRequest1 message is used and the resumeIdentity field in the RRCResumeRequest1 message is set to the fullI-RNTI stored by the UE; otherwise, RRCResumeRequest is used and the resumeIdentity field in the RRCResumeRequest message is set to the stored shortI-RNTI. The RRC release message RRCRelease is used to command the release of an RRC connection or the suspension of an RRC connection. The RRC reconfiguration message RRCReconfiguration is used to command the modification of the RRC connection. The RRC recovery message RRCResume is used to resume a suspended RRC connection. In the present disclosure, the useFullResumeID field indicates the recovery identifier and recovery request message used. When the field is included in SIB1, fullI-RNTI and RRCResumeRequest1 message are used. When the field is not included in SIB1, shortI-RNTI and RRCResumeRequest message are used. ShortI-RNTI uses fewer bits than I-RNTI-Value to identify the suspended UE context of a UE in an RRC inactive state. The RRC recovery process (i.e., the RRC connection recovery process) is used to restore the suspended RRC connection, including restoring SRB(s), DRB(s) and multicast MRB(s), or performing RNA updates, or implementing MBS multicast reception requests, or initiating small data transmission SDT in the RRC_INACTIVE state, etc. During the RRC recovery process, the UE sends an RRC recovery request message to the base station, and may receive an RRC recovery message RRCResume or an RRC setup message RRCSetup or an RRC release message RRCRelease or an RRC rejection message RRCReject from the base station.

[0070] In the present invention, network, base station and RAN can be used interchangeably. The network can be a long-term evolution LTE network, a NR network, an enhanced long-term evolution eLTE network, or other networks defined in subsequent evolution versions of 3GPP.

[0071] Currently, NR MBS services include MBS broadcast (also known as MBS broadcast session, broadcast MBS, MBS broadcast service, or MBS broadcast service) and MBS multicast (also known as MBS multicast session, multicast MBS, MBS multicast service, or MBS multicast service). MBS broadcast provides a downlink-only MBS transmission mode for services with low quality of service (QoS), allowing UEs in RRC connected, RRC idle, and RRC inactive states to receive the MBS service. UEs obtain MBS broadcast configuration information broadcast by the network through the MBS control channel (MCCH).

[0072] Release 17 does not support UEs receiving MBS multicast sessions in the RRC inactive state. Therefore, before receiving MBS multicast services (i.e., MBS multicast sessions), the UE needs to establish an RRC connection with the base station. The base station (i.e., the network) then configures the resources or PTM configuration for the UE to receive MBS multicast services through dedicated RRC signaling (also known as RRC messages, such as RRC reconfiguration messages). The MBS radio bearer (MRB) for receiving these MBS multicast services is also configured for the UE by the base station through dedicated RRC signaling. Only UEs in the RRC connected state and configured with MRBs can receive the corresponding MBS multicast services. Therefore, when an MBS multicast session is activated by the core network or the base station has MBS multicast session data to send, the network that supports MBS multicast notifies UEs in the RRC idle state or RRC inactive state through a group notification mechanism. Upon receiving the group notification, UEs that have joined the MBS multicast session or are interested in the MBS multicast session establish or resume an RRC connection with the network to receive the corresponding MBS multicast session. The group notification is addressed using the P-RNTI on the Physical Downlink Control Channel (PDCCH), and the UE monitors the paging channel. The paging message used for group notification contains the MBS session identifier (TMGI), which is used to page all UEs that have joined the relevant MBS multicast session and are in RRC Idle or RRC Inactive state. In other words, the base station does not page UEs individually (for the purpose of UEs receiving the MBS multicast session).

[0073] Release 18 supports UEs receiving MBS multicast sessions in an RRC-inactive state. For MBS multicast sessions configured for reception in an RRC-inactive state, the base station can provide or configure PTM configuration information (also known as MBS multicast session configuration information or MBS multicast session PTM configuration or MBS multicast configuration) for the UE to receive the MBS multicast session through dedicated RRC signaling (e.g., RRCRelease message) or through the multicast MBS control channel MCCH (i.e., multicast MCCH). The information required to obtain the multicast MCCH (or multicast MCCH configuration) can be configured for the UE through dedicated RRC signaling or a system information block (denoted as SIB24). That is, SIB24 contains the information required to obtain the multicast MCCH / MTCH (i.e., MCCH and / or MTCH) configuration for MBS multicast reception in an RRC-inactive state. The PTM configuration information may include configuration information of the MRB corresponding to the MBS multicast session and / or the identifier TMGI of the MBS multicast session and its corresponding G-RNTI / G-CS-RNTI and / or fields of DRX configuration information. For example, the PTM configuration of a certain MBS multicast session is information related to the reception of the MBS multicast session contained in the MBS multicast configuration MBSMulticastConfiguration message. The MBSMulticastConfiguration message contains the control information applicable for MBS multicast services transmitted via multicast MRBs for RRC_INACTIVE UEs. The MBSMulticastConfiguration message may be transmitted on the multicast MCCH or included in the RRC release message. The multicast MCCH is a PTM downlink channel used for transmitting control information of MBS multicast session associated to one or several MTCH(s) from the network to the UE in RRC_INACTIVE state.For an MBS multicast session received in the RRC_INACTIVE state, in the embodiments of the present disclosure, the MBS multicast session being in an active state or being activated means that the MBS multicast session is ongoing or about to start, the UE starts receiving (or is receiving) the MBS multicast session, or the UE starts detecting the G-RNTI corresponding to the MBS multicast session, or the UE starts detecting (monitoring) the multicast-MCCH-RNTI of the multicast MCCH. The network can instruct the UE that the MBS multicast is activated or data transmission is resumed through RRC signaling (e.g., an RRC release message) or through a paging message. For example, including the TMGI of the MBS multicast session in a paging message indicates that the MBS multicast session is activated or data transmission is resumed, and not including the stopMonitoringRNTI field for indicating the stop of detection of the corresponding G-RNTI for the MBS multicast session in the RRC release message indicates that the MBS multicast session is activated or data transmission is resumed. After receiving the indication, the UE starts receiving the MBS multicast session (i.e., the UE starts detecting the G-RNTI corresponding to the MBS multicast session). The MBS multicast activation described in the embodiments of the present disclosure also applies to the case of resuming data transmission of an MBS multicast session, which will not be described in detail below. In the embodiments of the present disclosure, the MBS multicast session being in an inactive state or being deactivated means that the MBS multicast session has ended or suspended data transmission or the UE has stopped receiving the MBS multicast session (i.e., the UE has stopped detecting the G-RNTI corresponding to the MBS multicast session). The network associates an indication identifier with each MBS multicast session in the multicast MCCH message to explicitly indicate that the MBS multicast session is deactivated or stops detecting the G-RNTI corresponding to the MBS multicast session. After receiving the indication, the UE stops receiving the MBS multicast session. The UE stopping receiving the MBS multicast session may be the UE stopping detecting the G-RNTI or G-CS-RNTI corresponding to the MBS multicast session. Therefore, in the present disclosure, the indication of deactivation of the MBS multicast session or stopping data transmission is an indication instructing the UE to stop detecting the G-RNTI or G-CS-RNTI associated with the MBS multicast session. Furthermore, an indication that an MBS multicast session is activated or data transmission resumes is an indication to begin detecting the G-RNTI corresponding to the MBS multicast session. Deactivation of an MBS multicast session includes a situation where the MBS multicast session is temporarily not transmitting data, and activation of an MBS multicast session includes a situation where the MBS multicast session resumes data transmission. In this disclosure, a multicast session or service is an MBS multicast session or service. The following embodiments use G-RNTI as an example. Embodiments where G-RNTI is replaced with G-CS-RNTI are also within the scope of this disclosure.

[0074] Each MBS multicast session is identified by a TMGI and associated with a G-RNTI or G-CS-RNTI. The UE receives the MBS multicast session by detecting the G-RNTI or G-CS-RNTI associated with the MBS multicast session.

[0075] For a UE configured with an MBS multicast session that can be received in the RRC_INACTIVE state, when the MBS multicast session is activated or data transmission is resumed, if the MBS multicast session is configured and / or allowed to be received in the RRC_INACTIVE state and / or the UE has a (valid) PTM configuration for the MBS multicast session, the MBS multicast session can be directly received without establishing an RRC connection with the base station. The network can configure the PTM configuration information (for example, contained in an MBSMulticastConfiguration message) for the MBS multicast session received in the RRC_INACTIVE state for the UE via the multicast MCCH and / or dedicated RRC signaling (for example, an RRC release message, an RRC reconfiguration message). The MBS multicast configuration message MBSMulticastConfiguration can be transmitted on the multicast MCCH (in this case, the MBSMulticastConfiguration message can be called a multicast MCCH message) or included in an RRC release message. If the RRC release message is used to configure the PTM configuration information of the MBS multicast session received in the RRC_INACTIVE state for the UE, the network may include the MBSMulticastConfiguration message in the RRC release message sent to the UE.

[0076] In the disclosed embodiments, a multicast MCCH-RNTI (i.e., Multicast MCCH-RNTI) is used for dynamically scheduled multicast MCCH signaling and / or multicast MCCH change notification, or for dynamically scheduled MCCH signaling and / or MCCH change notification, or for scrambling a DCI or a CRC of a DCI format, or for scrambling a PDCCH for MBS multicast transmission, or for scrambling a DCI or a CRC of a DCI format for MBS multicast transmission, or for scheduling a PDSCH for transmission of an MBS multicast session. The DCI or DCI format may be DCI format 40 or DCI format 4_1.

[0077] When a UE in RRC_INACTIVE receives a paging message from a base station, if the paging message includes the TMGI of one or more MBS sessions to which the UE has joined (the TMGI is included in the pagingGroupList field in the paging message), and further, if the UE is not configured to receive MBS multicast in RRC_INACTIVE (that is, the most recently received RRC release message does not include the multicastConfigInactive field), or there is at least one MBS multicast session to which the UE has joined, indicated by the TMGI included in the paging message, which is not indicated by the paging message as receivable in RRC_INACTIVE (that is, the paging message does not include the inactiveReceptionAllowed field corresponding to at least one MBS session indicated by the TMGI included in the paging message to which the UE has joined), and if it is also satisfied that the paging message does not include the PagingRecordList field or the ue-Identity included in any pagingRecord in the PagingRecordList field contained in the paging message does not match the UE identity allocated by an upper layer and the full-RNTI stored by the UE, then the RRC connection recovery procedure is initiated. Among them, the PagingRecordList domain is a pagingRecord list, and the pagingRecord domain contains the ue-Identity domain. The ue-Identity domain is used to indicate the ng-5G-S-TMSI or fullI-RNTI of the UE being paged. The fullI_RNTI domain carries the suspended UE context allocated by the base station to the UE through the RRC release message for identifying the UE in RRC_INACTIVE. The ng-5G-S-TMSI contains a 5G temporary mobile subscription identity 5G-S-TMSI, which is a temporary UE identity provided by the 5GC and is used to uniquely identify a UE in the tracking area.

[0078] The UE receives an RRC release message from the base station, and the multicastConfigInactive field included in the RRC release message indicates that the UE can receive multicast sessions or services in the current serving cell (i.e., the cell receiving the RRC release message) when the UE is in RRC_INACTIVE. When the multicastConfigInactive field is included in the received RRC release message, it indicates that the UE has been configured to receive MBS multicast in RRC_INACTIVE.

[0079] In the present disclosure, embodiments in which the function of the multicastConfigInactive field is replaced by one of the following are also within the scope of the present disclosure:

[0080] The multicastConfigInactive field indicates the multicast sessions or services that the UE can receive in the current serving cell when it is in RRC_INACTIVE, or the multicastConfigInactive field is used to indicate the multicast sessions or services that the UE can receive when it is in RRC_INACTIVE, or the multicastConfigInactive field is used to indicate the multicast sessions or services that the UE can receive when the current serving cell is in RRC_INACTIVE before obtaining the multicast MCCH, or the multicastConfigInactive field is used to indicate the multicast sessions or services that the UE can receive when it is in RRC_INACTIVE before obtaining the multicast MCCH.

[0081] Optionally, the multicastConfigInactive field also contains the corresponding configurations for these multicast sessions, which are valid in the current serving cell. The multicastConfigInactive field may contain two fields: the inactivePTM-Config field and the inactiveMCCH-Config field. The inactivePTM-Config field carries the MBSMulticastConfiguration message. The inactiveMCCH-Config field carries the system information SIB24.

[0082] For a UE configured to receive an MBS multicast session in RRC_INACTIVE, the UE receives a paging message to learn whether the MBS multicast session it has joined is activated and allowed to be received in the RRC_INACTIVE state. Specifically, if the paging message contains the TMGI of the MBS multicast session the UE has joined (the UE considers the MBS multicast session to be activated at this time) and its corresponding inactiveReceptionAllowed field, the UE considers the MBS multicast session to be activated and allowed to be received in RRC_INACTIVE, or the UE can receive the MBS multicast session in RRC_INACTIVE, or the UE starts to detect the G-RNTI of the MBS multicast session in RRC_INACTIVE. It should be noted that whether the UE receives the MBS multicast session in RRC_INACTIVE also depends on whether, when the UE receives the paging message, all other MBS multicast sessions to which the UE has joined, which are included in the paging message, are indicated as being receivable in RRC_INACTIVE. If at least one of the MBS multicast sessions to which the UE has joined, as indicated by the TMGI contained in the paging message, is not indicated by the paging message as being receivable in RRC_INACTIVE (i.e., the paging message does not include an inactiveReceptionAllowed field corresponding to at least one MBS session to which the UE has joined, as indicated by the TMGI contained in the paging message), then for other MBS multicast sessions to which the UE has joined, as indicated by the TMGI contained in the paging message, even if the paging message includes their corresponding inactiveReceptionAllowed fields, the UE will not receive these MBS sessions in RRC_INACTIVE. In other words, only when the inactiveReceptionAllowed fields corresponding to all MBS multicast sessions to which the UE has joined, as indicated by the TMGI contained in the paging message, are included in the paging message, will the UE receive in RRC_INACTIVE the MBS multicast sessions to which the UE has joined, as indicated by the TMGI contained in the paging message. The inactiveReceptionAllowed field is used to indicate whether a UE with a valid PTM configuration of the TMGI indicated in the pagingGroupList (ie, pagingGroupList-r17) included in the paging message stays in RRC_INACTIVE to receive the MBS multicast session indicated by the TMGI.

[0083] Currently, in addition to including the TMGI of the MBS multicast session in a paging message, activation indication of an MBS multicast session can also be achieved by indicating in the MBSMulticastConfiguration message whether to stop detecting the corresponding G-RNTI. Specifically, for an MBS multicast session whose TMGI is included in the MBSMulticastConfiguration message, if the MBSMulticastConfiguration message also includes a stopMonitoringRNTI field for the MBS multicast session, the MBS multicast session is deactivated (i.e., the UE stops detecting the G-RNTI of the MBS multicast session). Otherwise (i.e., the stopMonitoringRNTI field for the MBS multicast session is not included), the MBS multicast session is activated (i.e., the UE detects the G-RNTI of the MBS multicast session). The stopMonitoringRNTI field instructs the UE to stop detecting the G-RNTI of the corresponding MBS multicast session. Stopping detection of the G-RNTI of the MBS multicast session is indicated by associating / configuring a stopMonitoringRNTI field for each MBS multicast session. If an MBS multicast session is not associated with / configured with a corresponding stopMonitoringRNTI domain, it means that the MBS multicast session has not been instructed to stop detecting G-RNTI. The MBSMulticastConfiguration message can be transmitted on the multicast MCCH or included in the RRC release message. Specifically, the MBSMulticastConfiguration message can be included in the MulticastConfigInactive field in the suspendConfig field in the RRC release message. The suspendConfig field indicates the configuration of the RRC_INACTIVE state; the MulticastConfigInactive field is used to indicate one or more MBS multicast services that can be received in RRC_INACTIVE (or one or more MBS multicast services that can be received in RRC_INACTIVE for the current serving cell or one or more MBS multicast services that can be received in RRC_INACTIVE before obtaining the multicast MCCH for the current serving cell), and optionally, also includes the configuration of the MBS multicast service (or the configuration of the MBS multicast service for the current serving cell or the configuration of the MBS multicast service that is valid for the current serving cell). The current serving cell refers to the cell where the UE receives the RRC release message.The serving cell or the cell in which the UE last or previously received the RRC release message may refer to the cell in which the UE last or previously received the RRC release message or the primary cell PCell. If the RRC release message received by the UE contains the MBSMulticastConfiguration message or the MulticastConfigInactive field, the UE is considered to be configured to receive MBS multicast in RRC_INACTIVE; or if the RRC release message received by the UE (or the MBSMulticastConfiguration message contained in the RRC release message) contains TMGI, the UE is considered to be configured to receive MBS multicast in RRC_INACTIVE. It should be noted that the UE obtaining the multicast MCCH means that the UE obtains the MBSMulticastConfiguration message from the multicast MCCH.

[0084] For all MBS multicast sessions that the UE has joined, if the UE is notified to stop detecting the corresponding G-RNTI, the UE stops detecting the multicast MCCH-RNTI. In other words, if the UE does not detect any G-RNTI, the UE stops detecting the multicast MCCH-RNTI.

[0085] For a UE configured with both small data transmission (SDT) and receiving an MBS multicast session in RRC_INACTIVE mode, if the UE does not detect paging messages and / or multicast MCCH-RNTI during the SDT process, it will not receive an indication that the MBS multicast session it has joined has been activated (including when data transmission has resumed), and thus will miss receiving the corresponding MBS multicast session. How to enable the UE to normally receive the MBS multicast session activation indication during the SDT process is a problem that needs to be solved.

[0086] The following embodiments are provided to solve this problem. In addition, the following embodiments are merely illustrative and are not intended to limit the present invention.

[0087] Unless otherwise specified, the UEs in the following embodiments are all UEs configured with both small data transmission SDT and receiving MBS multicast sessions in RRC_INACTIVE. The MBS multicast sessions are all MBS multicast sessions that the UE has joined (or the MBS multicast sessions that the UE has joined and is configured to receive in RRC_INACTIVE), and no further details are given.

[0088] Example 1

[0089] During the SDT process, the base station indicates activation information of the MBS multicast session to the UE through dedicated RRC signaling, and the RRC signaling may be an RRC release message.

[0090] In the existing SDT process, if the UE receives an RRC release message, the UE will perform operations such as resetting the MAC and / or suspending the radio bearer and / or entering RRC_INACTIVE or RRC_IDLE and / or performing cell selection, which will cause the SDT process to be interrupted (i.e., stopped). Therefore, an indicator identifier (referred to as the first indicator identifier) ​​is added to the RRC release message to achieve both indicating the activation information of the MBS multicast session to the UE and avoiding interrupting the SDT process. The function of the indicator identifier can be one of the following: used to instruct the UE to maintain the SDT process, used to instruct the UE to terminate the SDT process, used to indicate that the MBS multicast session is activated, used to instruct the UE to detect the G-RNTI of the MBS multicast session (i.e., used to instruct the UE to detect the G-RNTI of one or more MBS multicast sessions), used to instruct the UE to detect the multicast MCCH-RNTI, and used to instruct the UE not to perform the operations performed by entering RRC_INACTIVE or RRC_IDLE. After receiving the RRC release message containing (or not containing) the indication identifier, the UE receives the corresponding MBS multicast session but does not perform the existing operations performed by the UE upon receiving the RRC release message (i.e., does not terminate the SDT process, or does not reset the MAC and / or does not suspend the radio bearer and / or does not perform cell selection, etc.). This is described in detail below.

[0091] The first indication identifier can be directly included in the suspendConfig field in the RRC release message (that is, the first indication identifier and the multicastConfigInactive field are two independent fields directly included in the suspendConfig), or can be included in the multicastConfigInactive field. The indication identifier can also be directly included in the RRC release message (that is, the first indication identifier and the suspendConfig are two independent fields).

[0092] The following describes in detail a method executed by a user equipment according to embodiment 1 of the present invention.

[0093] FIG1 is a schematic flow chart showing a method executed by a user equipment in embodiment 1 of the present invention. As shown in FIG1 , the method executed by the user equipment in embodiment 1 may include the following steps:

[0094] In step 101, a user equipment UE receives an RRC release message from a base station.

[0095] In step 103, if the RRC release message includes a first indication identifier (or includes a suspendConfig field and the suspendConfig field includes the first indication identifier), the first indication identifier may be used to instruct the UE to maintain the SDT process, or to indicate that the MBS multicast session is activated, or to instruct the UE not to perform the operation performed by entering RRC_INACTIVE or RRC_IDLE, or to instruct the UE to detect a multicast MCCH-RNTI, or to instruct the UE to detect a G-RNTI of an MBS multicast session, then at least one of the following operations is performed:

[0096] Operation 1-1a: Apply the multicast PTM configuration or apply the multicast PTM configuration included in the RRC release message (or the multicast PTM configuration included in the multicastConfigInactive field of the RRC release message).

[0097] Operation 1-1b: If the RRC release message includes the multicastConfigInactive field, apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field; and / or if the RRC release message does not include the multicastConfigInactive field, obtain the MBSMulticastConfiguration message on the multicast MCCH.

[0098] Operation 1-1c: If the RRC release message contains the multicastConfigInactive field and the MBS multicast session indicated by at least one TMGI contained therein is not indicated to stop detecting G-RNTI and the PTM configurations of all MBS multicast sessions that are not indicated to stop detecting G-RNTI are contained in the multicastConfigInactive field, apply the multicast PTM configuration or apply the multicast PTM configuration contained in the multicastConfigInactive field; and / or if the RRC release message does not contain the multicastConfigInactive field or there is an MBS multicast session that is not indicated to stop detecting G-RNTI (i.e., an MBS multicast session that has been joined or an MBS multicast session that has been joined and configured for RRC_INACTIVE reception) whose PTM configuration is not contained in the multicastConfigInactive field, obtain the MBSMulticastConfiguration message on the multicast MCCH.

[0099] Operation 1-1d: If the RRC release message contains the multicastConfigInactive field and / or the inactivePTM-Config field, apply the PTM configuration or apply the PTM configuration contained in the inactivePTM-Config field; and / or if the RRC release message does not contain the inactivePTM-Config field, obtain the MBSMulticastConfiguration message on the multicast MCCH.

[0100] Operation 1-1e: Detect multicast MCCH-RNTI (performed only when multicast MCCH-RNTI exists or multicast MCCH or system information SIB24 is supported). Alternatively, detect the G-RNTI of all joined MBS multicast sessions (or all joined MBS multicast sessions configured for RRC_INACTIE reception).

[0101] Operation 1-1f: The first indicator includes a G-RNTI list, and the UE detects the G-RNTI included in the first indicator. Or the first indicator includes a bitmap that corresponds one-to-one with the TMGI (the TMGI may be the TMGI of the MBS multicast session that the UE has joined and is configured to receive RRC_INACTIVE or the TMGI included in the previously received RRC release message), and the bits in the bitmap are used to indicate whether the corresponding MBS multicast session is activated or whether the UE detects the G-RNTI of the corresponding MBS multicast session. The UE detects the corresponding G-RNTI by taking the value of the bit in the bitmap. For example, the UE detects the G-RNTI of the MBS multicast session corresponding to the bit set to 1 or 0 in the bitmap.

[0102] Operation 1-1g: The process ends.

[0103] Optionally, if the RRC release message does not include the first indication identifier, the UE may perform at least one of the following operations:

[0104] Operation 1-1A: Reset MAC and / or release the default MAC cell group configuration (executed only if it exists).

[0105] Action 1-1B: Suspend all SRBs and DRBs except SRB0 and broadcast MRB.

[0106] Action 1-1C: Suspend all multicast MRBs associated to multicast sessions that are not configured for RRC_INATIVE reception.

[0107] Action 1-1D: Enter RRC_INACTIVE and / or perform cell selection.

[0108] Operation 1-1E: Perform operations performed upon entering RRC_IDLE, such as resetting MAC and / or entering RRC_IDLE and / or performing cell selection.

[0109] Optionally, it is specified that the first indicator is included in suspendConfig only when the multicastConfigInactive field is included in suspendConfig (ie, included in the RRC release message). In other words, if the first indicator is included in suspendConfig, the multicastConfigInactive field must be included in suspendConfig.

[0110] If the first indication identifier is used to instruct the UE to terminate the SDT process or to indicate that the RRC release message is not for MBS multicast activation, a new embodiment can be obtained by replacing step 103 with step 103a.

[0111] Step 103a: If the RRC release message does not include the first indicator, perform at least one of operations 1-1a to 1-1g. Optionally, if the RRC release message includes the first indicator, perform at least one of operations 1-1A to 1-1E.

[0112] If the first indication identifier is the multicastConfigInactive field, a new embodiment can be obtained by replacing step 103 with step 103b.

[0113] Step 103b: If the SDT process is in progress and / or the RRC release message contains the multicastConfigInactive field, perform at least one of the following operations:

[0114] Operation 1-1I: Apply the multicastConfigInactive field and / or detect the multicast MCCH-RNTI (performed only when the multicast MCCH-RNTI exists or the multicast MCCH or system information SIB24 is supported). Specifically, applying the multicastConfigInactive field may include: if the multicastConfigInactive field (or the RRC release message) includes a multicast PTM configuration and / or the PTM configuration of the MBS multicast session for which all TMGIs are included in the RRC release message but not indicated to stop detecting G-RNTI is included in the RRC release message, applying the multicast PTM configuration in the RRC release message and / or detecting the multicast MCCH-RNTI (performed only when the multicast MCCH-RNTI exists or the multicast MCCH or system information SIB24 is supported). Optionally, if the multicastConfigInactive field (or the RRC release message) does not include a multicast PTM configuration and / or there is at least one TMGI included in the RRC release message but the PTM configuration of the MBS multicast session that is not indicated to stop detecting G-RNTI is not included in the RRC release message, then obtaining and / or applying an MBSMulicastConfiguration message and / or detecting a multicast MCCH-RNTI on the multicast MCCH. The applying the multicast PTM configuration (or applying the MBSMulicastConfiguration message) includes the UE detecting the G-RNTI of the MBS multicast session that is not indicated to stop detecting G-RNTI and is included in the multicast PTM configuration (or MBSMulicastConfiguration message).

[0115] Operation 1-111: Detect multicast MCCH-RNTI. Specifically, if there is at least one MBS multicast session configured for RRC_INACTIVE reception and is not instructed to stop detecting G-RNTI, detect the multicast MCCH-RNTI.

[0116] Operation 1-1III: The process ends.

[0117] Optionally, if the RRC release message does not include the multicastConfigInactive field, perform at least one of operations 1-1A to 1-1E.

[0118] Example 2

[0119] If the multicast MCCH information (i.e., the information transmitted in the message sent on the multicast MCCH) changes, the base station will indicate it in the DCI used to schedule the multicast MCCH information, and the UE can learn about the change (i.e., obtain the multicast MCCH change notification) by detecting the multicast MCCH-RNTI. However, if the UE does not detect any G-RNTI during the SDT process, the UE does not detect the multicast MCCH-RNTI at this time, and cannot learn the activation information of the MBS multicast session (i.e., whether the corresponding MBS multicast session is activated or whether the corresponding MBS multicast session is instructed to stop detecting G-RNTI). Therefore, during the SDT process, even if the UE does not detect any G-RNTI, the UE also detects the multicast MCCH-RNTI. When the DCI detected according to the multicast MCCH-RNTI indicates that the multicast MCCH information has changed, the UE obtains the MBSMulticastConfiguration message from the multicast MCCH to learn the activation information of the MBS multicast session.

[0120] Furthermore, because multicast MCCH information changes only occur in specific frames, the same multicast MCCH information may be transmitted multiple times within a modification period. To save energy, during the SDT process, if the UE does not detect any G-RNTI, the UE detects the multicast MCCH-RNTI at least once within the modification period of the multicast MCCH information. For example, the UE detects the multicast MCCH-RNTI at the beginning of each modification period. If no multicast MCCH change notification is received, the UE does not need to detect the multicast MCCH-RNTI again within the modification period.

[0121] The failure to detect any G-RNT may be replaced by all joined MBS multicast sessions (or MBS multicast sessions configured for RRC_INACTIVE reception, or joined MBS multicast sessions configured for RRC_INACTIVE reception) being notified to stop detecting the corresponding G_RNTI.

[0122] The following describes a method performed by a user equipment in accordance with Embodiment 2 of the present invention in conjunction with FIG2 . FIG2 is a schematic flow chart illustrating a method performed by a user equipment in accordance with Embodiment 2 of the present invention. As shown in FIG2 , the method performed by a user equipment in accordance with Embodiment 2 may include the following steps:

[0123] In step 201, the user equipment initiates an RRC connection recovery procedure.

[0124] In step 203, if the SDT start condition is met, further, if the UE is configured to receive MBS multicast in RRC_INACTIVE and / or the UE is not detecting the multicast MCCH-RNTI, the multicast MCCH-RNTI is detected.

[0125] Optionally, in step 205, transmission of an RRC recovery request message is initiated.

[0126] The following briefly describes the conditions for initiating SDT, see TS38.331-i00 and TS38.321-i00 for details. If the following conditions are met, the UE in RRC_INACTIVE starts the RRC recovery procedure for SDT:

[0127] For the RRC recovery procedure to be triggered by upper layers (i.e., mobile originated), all of the following conditions must be met:

[0128] (1) SIB1 contains sdt-ConfigCommon;

[0129] (2) sdt-Config is configured;

[0130] (3) All pending uplink data is mapped to the radio bearer configured for SDT;

[0131] (4) For an (e)RedCap UE, when the (e)RedCap UE-specific initial downlink BWP does not contain CD-SSB, but is configured with ncd-SSB-RedCapInitialBWP-SDT;

[0132] (5) The lower layer (ie, the MAC layer) indicates that the conditions for starting MO-SDT have been met.

[0133] For the RRC recovery process triggered by responding to a RAN paging call (i.e., mobile terminated), all of the following conditions must be met:

[0134] (i) The paging message contains the mt-SDT indication for the fullI-RNTI stored by the UE;

[0135] (ii) The lower layer (ie, the MAC layer) indicates that the conditions for starting MT-SDT have been met.

[0136] The following briefly describes the meaning or function of each of the above fields. The sdt-ConfigCommon field contains information such as parameters for determining whether to start the SDT process and the value of the timer T319a used by the SDT process, such as the field sdt-RSRP-Threshold containing the RSRP threshold used to determine whether to start the SDT process, and the field sdt-DataVolumeThreshold containing the data volume threshold used to determine whether to start the SDT process. The sdt-Config field is included in the RRC release message and is used to configure information related to the radio bearer supporting SDT or the resources used by the SDT process. The ncd-SSB-RedCapInitialBWP-SDT field is used to instruct the UE to use the (e)RedCap-specific initial DL BWP associated with the NCD-SSB used for SDT. The mt-SDT field is an SDT indication for the mobile terminal.

[0137] [Variation of Example 2]

[0138] The embodiment is obtained by replacing step 203 in embodiment 2 with the following step 203a.

[0139] In step 203a, if the SDT start condition is met, further, if the UE is configured to receive MBS multicast in RRC_INACTIVE, the UE detects the G-RNTIs of all joined MBS multicast sessions (or all joined MBS multicast sessions configured for RRC_INACTIVE reception).

[0140] The following describes an embodiment of operations performed by the UE upon receiving the RRC release message.

[0141] When the UE receives an RRC release message, for example, the RRC release message is a message received after the UE initiates an RRC recovery process for SDT (that is, the UE performs the SDT process), if the UE is detecting multicast MCCH-RNTI, but the UE is not configured to receive the MBS multicast session in RRC_INACTIVE when receiving the RRC release message (that is, the UE is no longer configured to receive the MBS multicast session in RRC_INACTIVE) or all MBS multicast sessions that the UE has joined (or all MBS multicast sessions that have been joined and configured for RRC_INACTIVE reception) are instructed to stop detecting the corresponding G-RNTI, then the UE stops detecting the multicast MCCH-RNTI.

[0142] FIG3 is a schematic flow chart illustrating an embodiment of operations performed by a UE upon receiving an RRC release message.

[0143] As shown in FIG3 , in step 301 , the user equipment UE receives an RRC release message from the base station.

[0144] In step 303, if the RRC release message does not include the multicastConfigInactive field, the detection of the multicast MCCH-RNTI is stopped.

[0145] Optionally, for example, in step S303, if the RRC release message does not contain the multicastConfigInactive field and the UE does not detect any G-RNTI (i.e., all MBS multicast sessions that have joined and / or are configured for RRC_INACTIVE reception are notified to stop detecting G-RNTI), then the detection of multicast MCCH-RNTI may be stopped.

[0146] The base station can instruct the UE to end the SDT state by sending an RRC release message that does not contain the multicastConfigInactive field to the UE. However, at the end of the SDT, if certain MBS multicast configuration information needs to be changed, the base station must first send an RRC release message with the multicastConfigInactive field to the UE to configure or update the configuration of the MBS multicast session, and then send an RRC release message that does not contain the multicastConfigInactive field to the UE to instruct the UE to end the SDT process. This process has a large signaling overhead. Therefore, the above step 303 can be replaced with the following step 303a to obtain a new embodiment to solve this problem.

[0147] In step 303a, if the UE does not include the multicastConfigInactive field in the received RRC release message, further, if SDT is in progress or has been configured to receive the MBS multicast session in RRC_INACTIVE (that is, the UE is configured to receive the MBS multicast session in RRC_INACTIVE before receiving the RRC release message), optionally, it is also satisfied that the UE does not detect the multicast MCCH-RNTI, and optionally, it is also satisfied that if the selected cell is the serving cell (or the cell receiving the RRC release message), the MBSMulticastConfiguration message is obtained from the multicast MCCH.

[0148] It should be noted that, in the present disclosure, obtaining the MBSMulticastConfiguration message on the multicast MCCH may refer to obtaining the MBSMulticastConfiguration message from the multicast MCCH of the concerned cell in the next repetition period. The cell or the concerned cell may refer to the serving cell or the cell in which the UE receives the RRC release message or the PCell when the UE receives the RRC release message. In the present disclosure, the UE being configured to receive MBS multicast in RRC_INACTIVE means that the UE includes the multicastConfigInactive field in the received (i.e., previously or most recently received) RRC release message.

[0149] In the present disclosure, the serving cell is the cell in which the UE receives the RRC release message. The TMGI contained in the paging message refers to the TMGI contained in the pagingGroupList-r17 field contained in the paging message. When the TMGI is contained in the pagingGroupList-r17 field, it indicates that the MBS multicast session indicated by the TMGI is activated or starts data transmission. For an MBS multicast session configured for RRC_INACTIVE reception, when the UE receives the TMGI of the MBS multicast session contained in the paging message, the UE further determines whether the paging message contains the inactiveReceptionAllowed field corresponding to the TMGI. If the paging message contains the inactiveReceptionAllowed field corresponding to the TMGI or the inactiveReceptionAllowed field corresponding to the TMGI contained in the paging message is set to "true" or true, it indicates that the UE can receive the MBS multicast session in the RRC_INACTIVE state when receiving the paging message. The inactiveReceptionAllowed field is included in the pagingGroupList-v18xy field in the paging message, where x and y can be any natural numbers, for example, xy is "00". pagingGroupList-v18xy has the same number and order of elements as pagingGroupList-r17. The first element in pagingGroupList-v18xy corresponds to the first TMGI in pagingGroupList-r17, the second element in pagingGroupList-v18xy corresponds to the second TMGI in pagingGroupList-r17, and so on. The inactiveReceptionAllowed field is used to indicate whether a UE with a valid PTM configuration for the TMGI indicated in the pagingGroupList (i.e., pagingGroupList-r17) stays in RRC_INACTIVE to receive the MBS multicast session indicated by the TMGI.

[0150] Currently, when a UE receives an RRC release message, if the RRC release message includes the multicastConfigInactive field, the RRC release message provides a PTM configuration for a multicast session that is not instructed to stop detecting G-RNTIs, and the UE selects a cell to receive the RRC release message, the UE applies the multicast PTM configuration contained in the RRC release message and detects the multicast MCCH-RNTI. However, if the multicast PTM configuration contained in the RRC release message is not applied due to conditions not being met upon receiving the RRC release message, and the UE receives a paging message that includes the TMGI of the MBS multicast session to which the UE has joined and its corresponding inactiveReceptionAllowed field, and the PTM configuration for the MBS multicast session indicated by the TMGI is included in the previously received RRC release message, and if the current serving cell does not provide a multicast MCCH, the UE will not be able to receive the MBS multicast session in RRC_INACTIVE mode. The inactiveReceptionAllowed field is used to indicate whether a UE with a valid PTM configuration of the TMGI indicated in the pagingGroupList (ie, pagingGroupList-r17) included in the paging message stays in RRC_INACTIVE to receive the MBS multicast session indicated by the TMGI.

[0151] The following embodiments are provided to solve this problem.

[0152] In step 401, the UE receives an RRC release message from a base station.

[0153] In step 403, if the RRC release message configures the UE to receive the MBS multicast session in RRC_INACTIVE (i.e., the RRC release message contains the multicastConfigInactive field), and the RRC release message provides a multicast PTM configuration for at least one MBS multicast session, and the UE selects a cell to receive the RRCRelease, the UE performs at least one of the following operations:

[0154] Operation 5-1: Apply the multicast PTM configuration included in the RRC release message.

[0155] Operation 5-2: If at least one MBS multicast session configured to be received in RRC_INACTIVE (or configured to be received in RRC_INACTIVE in the RRC release message) is not instructed not to stop detecting the G-RNTI, detect the multicast MCCH-RNTI.

[0156] It should be noted that the RRC release message in each embodiment may be the same RRC release message. The embodiments executed by the UE or base station in the present disclosure may be executed by the RRC entity in the UE or base station or executed at the RRC layer. In the present disclosure, fields, domains, and information elements may be used interchangeably. In the embodiments of the present disclosure, if multiple operations are included, the embodiments obtained by changing the execution order of the operations are also within the scope of protection of the present disclosure. When multiple parallel judgment conditions are included, the embodiments obtained by changing the order of the judgment conditions are also within the scope of protection of the present disclosure.

[0157] 4 is used to illustrate a user equipment as an embodiment that can execute the method executed by the user equipment described in detail above in the present invention.

[0158] FIG4 is a block diagram showing a user equipment UE according to the present invention.

[0159] As shown in Figure 4, the user equipment UE 400 includes a processor 401 and a memory 402. The processor 401 may include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 402 may include, for example, a volatile memory (such as a random access memory (RAM), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memory. The memory 402 stores program instructions. When executed by the processor 401, the instructions may execute the above-described method performed by the user equipment as described in detail in the present invention.

[0160] The method and user equipment executed by the user equipment involved in the present invention are described in detail above based on Example 1, Example 2, etc. However, the present invention is not limited to the method and user equipment executed by the user equipment, and can also be implemented in other ways as long as the main purpose of the present invention can be achieved.

[0161] Those skilled in the art will appreciate that, for example, the present invention can be implemented by a method executed by a base station and the base station, or by a communication system including user equipment and a base station. For example, the method executed by the base station involved in the present invention may include steps corresponding to the technical features of the method executed by the user equipment, and the base station involved in the present invention may include features corresponding to the technical features of the structure of the user equipment. For details, please refer to the contents of the above embodiments and will not be repeated here.

[0162] As an example, in a method executed by a base station, the base station may send an RRC release message to a user equipment UE. In addition, a first indication identifier may be included in the RRC release message. Regarding the RRC release message, the first indication identifier, and the actions performed by the user equipment UE that receives the RRC release message, reference may be made to the above-described content and will not be repeated here.

[0163] The method and related apparatus of the present disclosure have been described above in conjunction with preferred embodiments. Those skilled in the art will appreciate that the methods described above are merely exemplary and that the various embodiments described above can be combined with one another unless conflicts arise. The method of the present disclosure is not limited to the steps and sequence described above.

[0164] In the embodiments of the present disclosure, when multiple operations are involved, the embodiments of the present disclosure exemplarily list the execution order of each operation, and the embodiments obtained by changing the execution order of each operation are also within the scope of protection of the present disclosure. In addition, when multiple judgment conditions are involved, the embodiments obtained by changing the execution order of each judgment condition are also within the scope of protection of the present disclosure. In addition, in the present disclosure, unless otherwise specified, the meaning of the fields defined in one embodiment can also be applied to the corresponding fields involved in other embodiments. In addition, in the embodiments of the present disclosure, "if...", "when...", "when...", "at...", "satisfy..." or "satisfy..." conditions" can be replaced with "under the circumstances...". In the embodiments of the present disclosure, the embodiments obtained by replacing "and" in some or all conditions with "or" are also within the scope of protection of the present disclosure; the embodiments obtained by replacing "or" in some or all conditions with "and" are also within the scope of protection of the present disclosure.

[0165] In addition, the user equipment shown above may include more modules, for example, modules that can be developed or will be developed in the future and can be used for a base station, MME, or UE, etc. The various identifiers shown above are merely exemplary and not restrictive, and the present disclosure is not limited to the specific information elements used as examples of these identifiers. Those skilled in the art may make many changes and modifications based on the teachings of the illustrated embodiments.

[0166] It should be understood that the above embodiments of the present disclosure can be implemented through software, hardware, or a combination of software and hardware. For example, the various components within the base station and user equipment in the above embodiments can be implemented through a variety of devices, including but not limited to: analog circuit devices, digital circuit devices, digital signal processing (DSP) circuits, programmable processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic devices (CPLDs), and the like.

[0167] In addition, the computer executable instructions or programs running on the device according to the present invention can be programs that enable the computer to implement the functions of the embodiments of the present invention by controlling the central processing unit (CPU). The program or the information processed by the program can be temporarily stored in a volatile memory (such as a random access memory RAM), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memory systems.

[0168] The computer executable instructions or program for realizing each embodiment of the present invention function can be recorded on a computer-readable storage medium. The corresponding function can be realized by making a computer system read the program recorded on the recording medium and executing these programs. The so-called "computer system" herein can be a computer system embedded in the device, and can include an operating system or hardware (such as a peripheral device). "Computer-readable storage medium" can be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a short-term dynamic storage program recording medium or any other recording medium that is computer-readable.

[0169] The various features or functional modules of the devices used in the above embodiments can be implemented or executed by circuits (e.g., single-chip or multi-chip integrated circuits). The circuits designed to perform the functions described in this specification may include general-purpose processors, digital signal processors (DSPs), proprietary integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of the above devices. The general-purpose processor may be a microprocessor, or any existing processor, controller, microcontroller, or state machine. The above circuits may be digital circuits or analog circuits. In the event that new integrated circuit technologies have emerged to replace existing integrated circuits due to advances in semiconductor technology, one or more embodiments of the present invention may also be implemented using these new integrated circuit technologies.

[0170] Furthermore, the present invention is not limited to the above-described embodiments. Although various examples of the embodiments have been described, the present invention is not limited thereto. Fixed or non-mobile electronic devices installed indoors or outdoors can be used as terminal devices or communication devices, such as AV equipment, kitchen equipment, cleaning equipment, air conditioners, office equipment, vending machines, and other household appliances.

[0171] As described above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the specific structure is not limited to the above-described embodiments, and the present invention also includes any design changes that do not deviate from the main purpose of the present invention. In addition, various modifications can be made to the present invention within the scope of the claims, and embodiments obtained by appropriately combining the technical means invented by different embodiments are also included in the technical scope of the present invention. In addition, components with the same effect described in the above embodiments can be replaced with each other.

Claims

1. A method performed by a User Equipment (UE), comprising: The UE receives an RRC release message from a base station; and When a first indication identifier is included in the RRC release message, where the first indication identifier is used to indicate that the UE maintains a Small Data Transfer (SDT) process, or indicates that an MBS multicast session is activated, or indicates that the UE does not perform the operations for entering RRC_INACTIVE or RRC_IDLE, or is used to indicate that the UE detects a multicast MCCH-RNTI, or is used to indicate that the UE detects the G-RNTI of a multicast MBS session, perform at least one of the following operations: Operation 1-1a: Apply a multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field included in the RRC release message; Operation 1-1b: If the RRC release message includes a multicastConfigInactive field, apply a multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field; and / or if the RRC release message does not include a multicastConfigInactive field, obtain an MBSMulticastConfiguration message on the multicast MCCH; Operation 1-1c: If the RRC release message includes a multicastConfigInactive field and at least one TMGI included therein indicates that the MBS multicast session is not indicated to stop detecting the corresponding G-RNTI and the PTM configurations of all MBS multicast sessions not indicated to stop detecting the G-RNTI are included in the multicastConfigInactive field, apply a multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field; and / or if the RRC release message does not include a multicastConfigInactive field or there is an MBS multicast session whose PTM configuration not indicated to stop detecting the G-RNTI is not included in the multicastConfigInactive field, obtain an MBSMulticastConfiguration message on the multicast MCCH; Operation 1-1d: If the RRC release message includes a multicastConfigInactive field and / or an inactivePTM-Config field, apply a PTM configuration or apply the PTM configuration included in the inactivePTM-Config field; and / or if the RRC release message does not include an inactivePTM-Config field, obtain an MBSMulticastConfiguration message on the multicast MCCH; Operation 1-1e: Detect the multicast MCCH-RNTI, or detect the G-RNTI of all joined MBS multicast sessions; Operation 1-1f: The first indication identifier includes a list of G-RNTIs, and the UE detects the G-RNTIs included in the first indication identifier; Operation 1-1g: The process ends.

2. The method performed by a user equipment UE according to claim 1, comprising: The RRC release message includes a suspendConfig field, and the first indication identifier is included in the suspendConfig field.

3. The method performed by a user equipment UE according to claim 1 or 2, comprising: In the case that the first indication identifier is not included in the RRC release message, the UE performs at least one of the following operations: Operation 1-1A: Reset the MAC and / or release the default MAC cell group configuration; Operation 1-1B: Suspend all SRBs and DRBs except SRB0 and the broadcast MRB; Operation 1-1C: Suspend all multicast MRBs associated with multicast sessions not configured for RRC_INATIVE reception; Operation 1-1D: Enter RRC_INACTIVE and / or perform cell selection; Operation 1-1E: Perform the operations performed to enter RRC_IDLE.

4. The method performed by a user equipment UE according to claim 2, comprising: When the multicastConfigInactive field is included in the suspendConfig, the first indication identifier is included in the suspendConfig.

5. A method performed by a user equipment UE, comprising: The UE receives an RRC release message from a base station; and When the first indication identifier is included in the RRC release message, and the first indication identifier is used to indicate that the UE aborts the small data transfer SDT process or indicates that the RRC release message is not for MBS multicast activation, perform at least one of the following operations: Operation 1-1A: Reset the MAC and / or release the default MAC cell group configuration; Operation 1-1B: Suspend all SRBs and DRBs except SRB0 and the broadcast MRB; Operation 1-1C: Suspend all multicast MRBs associated with multicast sessions not configured for RRC_INATIVE reception; Operation 1-1D: Enter RRC_INACTIVE and / or perform cell selection; Operation 1-1E: Perform the operations performed to enter RRC_IDLE.

6. The method performed by a user equipment UE according to claim 5, wherein In the case that the first indication identifier is not included in the RRC release message, perform at least one of the following operations: Operation 1-Ia: Apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field included in the RRC release message; Operation 1-1b: If the multicastConfigInactive field is included in the RRC release message, apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field; and / or if the multicastConfigInactive field is not included in the RRC release message, obtain the MBSMulticastConfiguration message on the multicast MCCH; Operation 1-1c: If the multicastConfigInactive field is included in the RRC release message and at least one TMGI indicated in the MBS multicast session included therein is not indicated to stop detecting the corresponding G-RNTI and the PTM configuration of all MBS multicast sessions not indicated to stop detecting the G-RNTI is included in the multicastConfigInactive field, apply the multicast PTM configuration or apply the multicast PTM configuration included in the multicastConfigInactive field; and / or if the multicastConfigInactive field is not included in the RRC release message or there is a PTM configuration of an MBS multicast session not indicated to stop detecting the G-RNTI that is not included in the multicastConfigInactive field, obtain the MBSMulticastConfiguration message on the multicast MCCH; Operation 1-1d: If the multicastConfigInactive field and / or the inactivePTM-Config field is included in the RRC release message, apply the PTM configuration or apply the PTM configuration included in the inactivePTM-Config field; and / or if the inactivePTM-Config field is not included in the RRC release message, obtain the MBSMulticastConfiguration message on the multicast MCCH; Operation 1-1e: Detect the multicast MCCH-RNTI, or detect the G-RNTIs of all joined MBS multicast sessions; Operation 1-1f: The first indication identifier includes a list of G-RNTIs, and the UE detects the G-RNTIs included in the first indication identifier; Operation 1-1g: The process ends.

7. A method performed by a user equipment UE, comprising: The UE initiates an RRC connection restoration process; When the condition for starting small data transmission SDT is satisfied and the UE is configured to receive MBS multicast in RRC_INACTIVE and / or the UE is not detecting the multicast MCCH-RNTI, detect the multicast MCCH-RNTI.

8. The method performed by the user equipment UE according to claim 7, further comprising: The UE receives an RRC release message from the base station; and Stop detecting the multicast MCCH-RNTI when the multicastConfigInactive field is not included in the RRC release message.

9. The method performed by a user equipment UE according to claim 7, further comprising: The UE receives an RRC release message from a base station; and When the multicastConfigInactive field is not included in the RRC release message and the UE does not detect any G-RNTI, stop detecting the multicast MCCH-RNTI.

10. A user equipment, comprising: A processor; and A memory storing instructions, wherein the instructions, when run by the processor, perform the method according to any one of claims 1 to 9.

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