User equipment, method executed by user equipment, base station, and method executed by base station

Abstract

Provided in the present invention are a user equipment (UE), a method executed by a UE, a base station, and a method executed by a base station. The UE includes a processor. The processor is configured to: receive a paging message; for an MBS session that is indicated by a TMGI(s) included in the paging message and that the UE has joined, if the UE has been configured to receive multicast in RRC_INACTIVE and inactiveReceptionAllowed fields corresponding to the TMGI(s) are all included in the paging message, execute the following operation: if the UE has been configured with a G-RNTI(s) corresponding to the TMGI(s), start to detect the G-RNTI(s); and for all multicast sessions that are indicated by the TMGI(s) and configured as RRC_INACTIVE reception and that the UE has joined, if the UE is notified that the UE should stop detecting the G-RNTI(s) of the multicast sessions, start to detect a multicast MCCH-RNTI, wherein the multicast MCCH-RNTI is used for dynamically scheduling multicast MCCH signaling and a multicast MCCH change notification.

Description

User equipment, method executed by the user equipment, base station, and method executed by the base station Technical Field

[0001] The present invention relates to the field of wireless communication technology, and more particularly, to a user equipment, a base station and a method thereof. 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 the 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 services (NRMBS) 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-h60, TS 38.331-h60, and TS 38.321-h60. 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.

[0004] Summary of the Invention

[0005] In order to solve at least part of the above problems, the present invention provides a user equipment, a base station and a method thereof, which can ensure that the UE detects and receives the multicast MCCH in time and reduce the delay of MBS multicast reception.

[0006] To achieve the above object, according to the present invention, a method performed by a user equipment (UE) is proposed, comprising: the UE in an RRC inactive state receiving a paging message from a base station; and

[0007] For one or more MBS sessions indicated by the TMGI contained in the paging message to which the UE has joined, if the following conditions are not met: the UE is not configured to receive MBS multicast in the RRC inactive state and the paging message does not contain at least one MBS session indicated by the TMGI and is not indicated as being received in the RRC inactive state, then detection of one or more G-RNTIs corresponding to the TMGI is started.

[0008] Preferably, if the UE is not detecting the multicast-MCCH-RNTI, then detecting the multicast-MCCH-RNTI is started. If the UE is detecting the multicast-MCCH-RNTI and the UE is notified to stop detecting the G-RNTI of at least one multicast session, and the cell in which the UE is currently camped is the cell in which the UE previously received an RRC release message but the PTM configuration of the MBS multicast session indicated by the TMGI is not included in the RRC release message, then obtaining an MBS multicast configuration message on the multicast MCCH that includes control information for receiving MBS multicast via a multicast MRB for UEs in an RRC-inactive state.

[0009] In addition, according to the present invention, a method performed by a user equipment (UE) is proposed, comprising: receiving an RRC release message from a base station; and performing at least one of the following operations I-II according to the RRC release message:

[0010] Operation I: If the RRC release message includes a PTM configuration indicated to stop detecting the MBS multicast session indicated by the corresponding G-RNTI, the UE does not perform cell selection;

[0011] Operation II: If the RRC release message includes an MBS multicast configuration message containing control information for receiving MBS multicast via a multicast MRB for an RRC-inactive UE, stop detecting all G-RNTIs not included in the MBS multicast configuration message.

[0012] In addition, according to the present invention, a user equipment is proposed, comprising: a processor; and a memory storing instructions, wherein the instructions execute the above method when executed by the processor.

[0013] In addition, according to the present invention, a method performed by a base station is proposed, wherein the base station communicates with a user equipment (UE), the method comprising: sending an RRC release message to the UE, the RRC release message carrying an MBS multicast configuration message including control information for receiving MBS multicast via a multicast MRB for UEs in an RRC-inactive state, for the UE in an RRC_INACTIVE state to determine whether to perform cell selection.

[0014] In addition, according to the present invention, a base station is proposed, comprising: a processor; and a memory storing instructions, wherein the instructions execute the above method when executed by the processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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:

[0016] FIG1 is a flowchart illustrating a method executed by a user equipment according to embodiment 1 of the present invention.

[0017] FIG2 is a flowchart illustrating a method executed by a user equipment according to embodiment 2 of the present invention.

[0018] FIG3 is a block diagram schematically illustrating a user equipment involved in the present invention.

[0019] FIG4 is a block diagram schematically showing a base station involved in the present invention. DETAILED DESCRIPTION

[0020] The following describes some of the terms involved in the present invention. For their specific meanings, please refer to the latest relevant 3GPP documents, such as TS38.300-h60, TS38.321-h60, TS38.323-h50, and TS38.331-h60. 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.

[0021] UE: User Equipment.

[0022] RRC: Radio Resource Control.

[0023] RRC_CONNECTED: RRC connected state.

[0024] RRC_INACTIVE: RRC inactive state.

[0025] RRC_IDLE: RRC idle state.

[0026] RAN: Radio Access Network.

[0027] NR: New RAT, new radio access technology.

[0028] MBS: Multicast / Broadcast Services. Multicast can also be called multicast.

[0029] AS: Access Stratum, access layer or access layer.

[0030] NAS: NonAccess Stratum, non-access layer or non-access layer.

[0031] RB: Radio Bearer. DRB is a data radio bearer.

[0032] 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.

[0033] TMGI: Temporary Mobile Group Identity, used to identify an MBS session.

[0034] RNTI: Radio Network Temporary Identifier, wireless network temporary identifier.

[0035] 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).

[0036] 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.

[0037] 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.

[0038] 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; otherwise, the term special cell refers to the PCell. For dual connectivity, the PSCell is the SCG cell in the secondary cell group (SCG) where the UE performs random access during the synchronous reconfiguration procedure.

[0039] G-RNTI: Group RNTI, group RNTI, used to scramble the scheduling and transmission of PTM for one or more MBS multicast services.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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 SIB 1, 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 establishment message RRCSetup or an RRC release message RRCRelease or an RRC rejection message RRCReject from the base station.

[0044] 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.

[0045] 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).

[0046] 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).

[0047] 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 referred to 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 system information blocks (denoted as SIBx), i.e., SIBx contains the information required to obtain the multicast MCCH / MTCH (i.e., MCCH and / or MTCH) configuration of the MBS multicast received in the 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 in a multicast MCCH or an 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, the MBS multicast session being in an active state or being activated in the embodiments of the present disclosure means that the MBS multicast session is in progress or is 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 may indicate to the UE through RRC signaling (e.g., an RRC release message) or through a paging message that the MBS multicast is activated or data transmission is resumed (e.g., 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 the UE starts receiving the MBS multicast session after receiving the indication (i.e., the UE starts detecting the G-RNTI corresponding to the MBS multicast session). The MBS multicast being activated in the embodiments of the present disclosure is also applicable to the case of resuming data transmission of the 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 data transmission has been suspended, 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 may notify the UE through a multicast MCCH message (for example, if the PTM configuration of the MBS multicast session or a specific part of the PTM configuration does not appear in the multicast MCCH message, it indicates that the MBS multicast session is deactivated, or an indicator identifier may be associated with each MBS multicast session to explicitly indicate that the MBS multicast session is deactivated or that detection of the G-RNTI corresponding to the MBS multicast session has stopped) or through a physical downlink control channel PDCCH (or downlink control information DCI) that schedules a multicast MCCH (or a multicast MCCH message). For example, one bit is used in the DCI of the PDCCH to indicate that the MBS multicast is deactivated or data transmission is suspended. After receiving the indication, the UE stops receiving the MBS multicast session. The UE stopping receiving the MBS multicast session may be that the UE does not detect the G-RNTI or G-CS-RNTI corresponding to the MBS multicast session. Therefore, in the present disclosure, the deactivation indication of the MBS multicast session is an indication instructing the UE to stop monitoring the G-RNTI or G-CS-RNTI associated with the MBS multicast session. In addition, the indication that the MBS multicast session is activated is an indication to start detecting the G-RNTI corresponding to the MBS multicast session. The deactivation of the MBS multicast session includes the situation where the MBS multicast session temporarily has no data transmission, and the activation of the MBS multicast session includes the situation where the MBS multicast session resumes data transmission.

[0048] 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.

[0049] 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, 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 (referred to as 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.

[0050] In the disclosed embodiments, the multicast-MCCH-RNTI is used for dynamically scheduled multicast MCCH signaling and / or multicast 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 4_0 or DCI format 4_1.

[0051] 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, and further, if the UE is configured to receive MBS multicast in RRC_INACTIVE and no MBS multicast session indicated by the TMGI is indicated by the paging message as receivable in RRC_INACTIVE (i.e., the paging message does not trigger the UE to initiate an RRC connection recovery procedure or does not cause the UE to submit the one or more TMGIs included in the paging message to upper layers), the UE determines whether to start detecting multicast-MCCH-RNTI based on whether it has received an indication to stop detecting G-RNTI for all joined multicast sessions. However, the MBS multicast sessions to which the UE has joined include two types: one type is MBS multicast sessions configured for RRC_INACTIVE reception, and the other type is MBS multicast sessions not configured for RRC_INACTIVE reception (i.e., MBS multicast sessions that can only be received in RRC_CONNECTED). For MBS multicast sessions not configured for RRC_INACTIVE reception, the UE will not receive an indication to stop detecting the corresponding G-RNTI for the multicast session. In other words, if there are already joined MBS multicast sessions that are not configured for RRC_INACTIVE reception, the condition "whether an indication to stop detecting the G-RNTI for all joined multicast sessions has been received" will not be met. Even if the UE receives an indication to stop detecting the corresponding G-RNTI for all MBS multicast sessions configured for RRC_INACTIVE reception, the UE will not start detecting multicast-MCCH-RNTIs. This will result in the UE not receiving an indication to stop detecting the G-RNTI for the active MBS multicast session and an indication of PTM configuration or MBSMulticastConfiguration message update. In addition, for an MBS multicast session indicated by at least one TMGI included in the paging message, if the UE is notified to stop detecting the G-RNTI of the MBS multicast session (i.e., receives a notification to stop detecting the G-RNTI of the MBS multicast session before receiving the paging message), and the PTM configuration of the MBS multicast session is not included in the most recently or previously received RRC release message, the UE will obtain the MBSMulticastConfiguration message on the multicast MCCH. In other words, if the PTM configuration of the MBS multicast session is included in the most recently or previously received RRC release message, the UE will not be triggered to obtain the MBSMulticastConfiguration message on the multicast MCCH.However, after receiving the RRC release message, the UE may select or reselect a cell, causing the UE to select or reselect or reside in a cell different from the cell in which the RRC release message was obtained. The PTM configuration currently saved by the UE is no longer valid. If the UE does not re-acquire it, it will not be able to correctly receive the MBS multicast session.

[0052] It should be noted that the MBS multicast session is not indicated by the paging message as being receivable in RRC_INACTIVE means that the paging message does not include the inactiveReceptionAllowed field corresponding to the MBS multicast session.

[0053] 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.

[0054] Example 1

[0055] FIG1 is a flowchart illustrating a method executed by a user equipment according to embodiment 1 of the present invention.

[0056] As shown in FIG1 , in step 101 , a user equipment UE in RRC_INACTVIE receives a paging message from a base station.

[0057] In step 103, for one or more MBS sessions indicated by the TMGI included in the paging message to which the UE has joined, if the conditions that the UE is not configured to receive MBS multicast in the RRC inactive state and the MBS session not including at least one TMGI indicated in the paging message is not indicated as being received in the RRC inactive state are not satisfied, detection of one or more G-RNTIs corresponding to the TMGI is initiated. Optionally, if the UE has not detected a multicast-MCCH-RNTI, detection of the multicast-MCCH-RNTI is initiated.

[0058] The following is a detailed description:

[0059] A user equipment (UE) in RRC_INACTVIE mode (unless otherwise specified, the UE described in this embodiment is this UE) receives a paging message from a base station. If the UE has joined one or more MBS sessions indicated by the TMGI included in the paging message and conditions A1 and / or A2 (referred to as the first condition) are not met, at least one of the following operations 1-3 is performed:

[0060] Operation 1: Start detecting one or more G-RNTIs corresponding to one or more TMGIs to which the UE has joined, as contained in the paging message. It should be noted that this operation is performed only when the UE has been configured with the G-RNTI corresponding to the TMGI (or the G-RNTI corresponding to the MBS multicast session indicated by the TMGI).

[0061] Operation 2: Determine whether the UE meets condition B (referred to as the second condition). If condition B is met, the UE starts detecting the multicast-MCCH-RNTI and / or obtains the MBSMulticastConfiguration message on the multicast MCCH.

[0062] Operation 3: Determine whether the UE meets condition B. If condition B is not met, further determine whether condition C (called the third condition) is met. If condition C is met, further determine whether condition D1, D2, D3, or D4 (called the fourth condition) is met. If condition D1, D2, D3, or D4 is met, obtain the MBSMulticastConfiguration message on the multicast MCCH.

[0063] Among them, the condition A1 is that the UE is not configured to receive MBS multicast in RRC_INACTIVE. In the present disclosure, the UE is not configured to receive MBS multicast in RRC_INACTIVE means that the UE does not include an MBSMulticastConfiguration message in the RRC release message received (or previously received) or although the MBSMulticastConfiguration message is included, the MBSMulticastConfiguration message does not include any TMGI; the condition A2 is that the paging message does not include at least one inactiveReceptionAllowed field of the MBS session indicated by the TMGI to which the UE has joined included in the paging message (or the paging message does not include at least one inactiveReceptionAllowed field of the MBS session indicated by the TMGI). In other words, at least one of the inactiveReceptionAllowed fields of all MBS sessions indicated by the TMGI to which the UE has joined included in the paging message is not included in the paging message, or the paging message does not include at least one MBS session indicated by the TMGI to which the UE has joined included in the paging message is not indicated as being received in RRC_INACTIVE. Condition B is that all MBS multicast sessions that the UE has joined and that are configured for RRC_INACTIVE reception have been notified to stop detecting the corresponding G-RNTI. Condition C is that the UE is notified to stop detecting the G-RNTI of at least one MBS multicast session indicated by a TMGI included in the paging message; in other words, the UE is notified to stop detecting the G-RNTI of at least one multicast session, which is a multicast session indicated by a TMGI included in the paging message that the UE has joined and that is configured for RRC_INACTIVE reception. The condition D1 is that the cell currently selected, reselected or resided by the UE is not the cell in which the UE received the RRC release message last or previously; the condition D2 is that the cell currently selected, reselected or resided by the UE is the cell in which the UE received the RRC release message last or previously, but the UE selected, reselected or resided in other cells (i.e., other cells different from the current cell) after receiving the RRC release message; the condition D3 is that the cell currently selected, reselected or resided by the UE is the cell in which the UE received the RRC release message last or previously, but the PTM configuration of the MBS multicast session indicated by the TMGI (i.e., the TMGI included in the paging message, and the UE has joined the MBS multicast session indicated by the TMGI, and the UE has been notified to stop detecting the G-RNTI corresponding to the TMGI) is not included in the RRC release message.

[0064] The TMGI included in the paging message in the present disclosure refers to the TMGI included in the pagingGroupList-r17 field included in the paging message. When the TMGI is included in the pagingGroupList-r17 field, it indicates that the MBS multicast session indicated by the TMGI is activated or data transmission starts. For an MBS multicast session configured for RRC_INACTIVE reception, when the UE receives the TMGI of the MBS multicast session included in the paging message, the UE further determines whether the paging message includes the inactiveReceptionAllowed field corresponding to the TMGI. If the paging message includes the inactiveReceptionAllowed field corresponding to the TMGI or the inactiveReceptionAllowed field corresponding to the TMGI included in the paging message is set to "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". The pagingGroupList-v18xy and pagingGroupList-r17 have the same number and order of elements. 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) should stay in RRC_INACTIVE to receive the MBS multicast session indicated by the TMGI.

[0065] Optionally, in the above embodiment, if condition A1 or A2 is met, the UE performs the following operations:

[0066] If the paging message does not contain the PagingRecordList field or all ue-Identities in the PagingRecordList field contained in the paging message do not match the UE identifier assigned by the upper layer or the fullI_RNTI stored by the UE, the RRC connection recovery process is started; otherwise, if the ue-Identity contained in a pagingRecord in the PagingRecordList field contained in the paging message matches the UE identifier assigned by the upper layer, the TMGI to which the UE has joined contained in the paging message is forwarded to the upper layer. Among them, the PagingRecordList domain is a pagingRecord list, 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 to the UE by the base station through the RRC release message for identifying the UE in RRC_INACTIVE, the pagingPecord domain contains the ue-Identity domain, and the ng-5G-S-TMSI contains a 5G temporary mobile subscription identifier 5G-S-TMSI, which is used to uniquely identify a UE in the tracking area. It is a temporary UE identifier provided by the 5GC.

[0067] [Variation of Example 1]

[0068] An embodiment obtained by replacing condition B in embodiment 1 with condition B1, B2, B3, or B4 while keeping other operations or conditions unchanged.

[0069] Condition B1: All MBS multicast sessions to which the UE has joined are notified to stop detecting the corresponding G-RNTI;

[0070] Condition B2: The UE does not detect (or is not detecting) the multicast-MCCH-RNTI;

[0071] Condition B3: There is no MBS multicast session being received or no G-RNTI being detected. In other words, when the UE processes the TMGI contained in the paging message or receives the paging message, there is no MBS multicast session being received or no G-RNTI being detected;

[0072] Condition B4: All MBS multicast sessions to which the UE has joined have been notified to stop detecting the corresponding G-RNTI, and before receiving the paging message, no paging message containing the TMGI of the joined MBS multicast session has been received (i.e., the UE has not been reactivated since the most recent or previous notification to stop detecting the corresponding G-RNTI).

[0073] The purpose of the RRC connection recovery process is to recover a suspended RRC connection, including recovering SRB, DRB, multicast MRB or performing RAN-based Notification Area (RNA) updates, or starting RRC_INACTIVE small data transmission (SDT).

[0074] Example 2

[0075] FIG2 is a flowchart illustrating a method executed by a user equipment according to embodiment 2 of the present invention.

[0076] As shown in FIG2 , in step 201 , an RRC release message is received from a base station.

[0077] In step 203, at least one of the following operations I-II is performed according to the received RRC release message:

[0078] Operation I: If the RRC release message includes a PTM configuration or mrb-ListMulticast-r18 field that indicates that the UE is to stop detecting the MBS multicast session indicated by the corresponding G-RNTI, the UE does not perform cell selection or reselection. In other words, if the RRC release message does not include a PTM configuration or mrb-ListMulticast-r18 field that indicates that the UE is to stop detecting the MBS multicast session indicated by the corresponding G-RNTI, the UE performs cell selection or reselection. Optionally, it may be provided that, for the MBS multicast session indicated by the G-RNTI, the corresponding thresholdIndex-r18 and mrb-ListMulticast-r18 fields are configured simultaneously. Among them, thresholdIndex-r18 indicates the thresholdMBS entry in the thresholdMBS-List field, which is used to resume the RRC connection of the UE receiving the corresponding multicast session in RRC_INACTIVE. The value 0 corresponds to the first entry in the thresholdMBS-List, the value 1 corresponds to the second entry in the thresholdMBS-List, and so on; the thresholdMBS-List field is a list of reception quality thresholds for RRC connection recovery for UEs receiving multicast in RRC_INACTIVE; the thresholdMBS field contains the RSRP or RSRQ threshold, and the UE determines whether to start RRC connection recovery for the purpose of receiving the corresponding MBS multicast session based on this threshold; the mrb-ListMulticast-r18 field is a list of multicast MRBs to which the associated MBS multicast session is mapped. Operation II: If the RRC release message includes an MBSMulticastConfiguration message, stop detecting (or instruct the lower layer to stop detecting) all G-RNTIs not included in the MBSMulticastConfiguration message and / or all G-RNTIs included in the MBSMulticastConfiguration message but indicated as, associated with, or configured with stopMonitoringRNTI. Optionally, the UE considers that an indication or notification to stop detecting the G-RNTI has been received.

[0079] It should be noted that in the embodiment of the present disclosure, the G-RNTI is included in the MBS-SessionInfoListMulticast field included in the MBSMulticastConfiguration message, and the MBS-SessionInfoListMulticast field provides the RRC_INACTIVE UE with a list of MBS multicast sessions sent via the multicast MRB, and for each MBS multicast session, provides the associated G-RNTI and scheduling information. The G-RNTI is used to scramble the scheduling and transmission of the multicast MTCH. The stopMonitoringRNTI field is used to instruct the UE to stop detecting the G-RNTI of the corresponding multicast session. The MBS-SessionInfoMulticast field included in the MBS-SessionInfoListMulticast field defines the relevant information of each multicast session, such as the multicast session identifier TMGI and its associated G-RNTI, the stopMonitoringRNTI field, the configuration information mrb-ListMulticast-r18 of the MRB of the multicast session, etc.

[0080] The MBSMulticastConfiguration message is included in the MulticastConfigInactive field of the suspendConfig field included 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), 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 in which 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 primary cell PCell in which the UE last or previously received the RRC release message. 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 mode; or if the RRC Release message received by the UE (or the MBSMulticastConfiguration message contained in the RRC Release message) contains the TMGI, the UE is considered to be configured to receive MBS multicast in RRC_INACTIVE mode. In this disclosure, a field is a field or an information element.

[0081] It should be noted that the embodiments executed by the UE or the base station in the present disclosure may be executed by an RRC entity in the UE or the base station or executed at the RRC layer.

[0082] [Modification]

[0083] 3 is used to illustrate a user equipment as a modified example that can execute the method executed by the user equipment described in detail above in the present invention.

[0084] FIG3 is a block diagram showing a user equipment UE according to the present invention.

[0085] As shown in Figure 3, the user equipment UE30 includes a processor 301 and a memory 302. The processor 301 may include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 302 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 302 stores program instructions. When executed by the processor 301, these instructions may execute the above-described method performed by the user equipment as described in detail in the present invention.

[0086] Next, FIG. 4 is used to illustrate a base station as a modified example that can execute the method executed by the base station described above in the present invention.

[0087] FIG4 is a block diagram showing a base station according to the present invention.

[0088] As shown in Figure 4, base station 40 includes a processor 401 and a memory 402. Processor 401 may include, for example, a microprocessor, a microcontroller, or an embedded processor. 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. Memory 402 stores program instructions. When executed by processor 401, these instructions may execute the above-described method performed by the base station as described in detail in the present invention.

[0089] Specifically, a base station according to the present invention communicates with a user equipment (UE). The base station sends a paging message or an RRC release message to the UE. The paging message carries a TMGI and an indication of whether the UE is allowed to remain in an RRC_INACTIVE state and receive an MBS multicast session indicated by the TMGI, so that the UE can determine whether to remain in the RRC_INACTIVE state and receive the MBS multicast session indicated by the TMGI. The RRC release message carries an MBS multicast configuration message for the UE in the RRC_INACTIVE state to determine whether to perform cell selection. For details, see the above description.

[0090] 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.

[0091] 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 may 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 the conditions..." can be replaced with "under the condition of...".

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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 user equipment UE, comprising a processor, wherein the processor is configured to: receiving paging messages; For the MBS session that the UE has joined indicated by the TMGI(s) contained in the paging message, if the UE is configured to receive multicast in RRC_INACTIVE and the inactiveReceptionAllowed fields corresponding to the TMGI(s) are all contained in the paging message, the following operations are performed: If the UE has been configured with the G-RNTI(s) corresponding to the TMGI(s), start detecting the G-RNTI(s); and For all multicast sessions indicated by the TMGI(s) that the UE has joined and is configured for RRC_INACTIVE reception, if the UE is notified to stop detecting the G-RNTI(s) of the multicast session, it starts detecting the multicast MCCH-RNTI, where the multicast MCCH-RNTI is used to dynamically schedule multicast MCCH signaling and multicast MCCH change notification.

2. A method performed by a user equipment UE, comprising: Receive paging messages; For the MBS session that the UE has joined indicated by the TMGI(s) contained in the paging message, if the UE is configured to receive multicast in RRC_INACTIVE and the inactiveReceptionAllowed fields corresponding to the TMGI(s) are all contained in the paging message, the following operations are performed: If the UE has been configured with the G-RNTI(s) corresponding to the TMGI(s), start detecting the G-RNTI(s); and For all multicast sessions indicated by the TMGI(s) that the UE has joined and is configured for RRC_INACTIVE reception, if the UE is notified to stop detecting the G-RNTI(s) of the multicast session, it starts detecting the multicast MCCH-RNTI, where the multicast MCCH-RNTI is used to dynamically schedule multicast MCCH signaling and multicast MCCH change notification.

3. A base station, comprising a processor, wherein the processor is configured to: Sending a paging message to a user equipment; For the MBS session that the UE has joined indicated by the TMGI(s) contained in the paging message, if the UE is configured to receive multicast in RRC_INACTIVE and the If the inactiveReceptionAllowed fields corresponding to the TMGI(s) are all included in the paging message, the following operations are performed: If the UE has been configured with the G-RNTI(s) corresponding to the TMGI(s), start detecting the G-RNTI(s); and For all multicast sessions indicated by the TMGI(s) that the UE has joined and is configured for RRC_INACTIVE reception, if the UE is notified to stop detecting the G-RNTI(s) of the multicast session, it starts detecting the multicast MCCH-RNTI, where the multicast MCCH-RNTI is used to dynamically schedule multicast MCCH signaling and multicast MCCH change notification.

4. A method performed by a base station, the base station communicating with a user equipment UE, the method comprising: Send paging messages; For the MBS session that the UE has joined indicated by the TMGI(s) contained in the paging message, if the UE is configured to receive multicast in RRC_INACTIVE and the inactiveReceptionAllowed fields corresponding to the TMGI(s) are all contained in the paging message, the following operations are performed: If the UE has been configured with the G-RNTI(s) corresponding to the TMGI(s), start detecting the G-RNTI(s); and For all multicast sessions indicated by the TMGI(s) that the UE has joined and is configured for RRC_INACTIVE reception, if the UE is notified to stop detecting the G-RNTI(s) of the multicast session, it starts detecting the multicast MCCH-RNTI, where the multicast MCCH-RNTI is used to dynamically schedule multicast MCCH signaling and multicast MCCH change notification.

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