Method and apparatus for mbs configuration and reception in mobile communication system

Abstract

According to an embodiment of the disclosure, there is provided a method for a terminal in a wireless communication system, the method comprising: receiving multicast and broadcast service (MBS) information from a base station; identifying an MBS service provided by the base station based on the MBS information; transmitting, to the base station, an RRC connection configuration request message for the identified MBS based on a temporary mobile group identity (TMGI) of the identified MBS included in the MBS information; receiving RRC connection configuration information from the base station; and receiving data corresponding to the identified MBS from the base station, wherein the TMGI of the identified MBS can include access category information for controlling access to the base station.

Description

Technical Field

[0001] This disclosure relates to the operation of user equipment (UE) and base stations for configuring and receiving multicast and broadcast services (MBS) in mobile communication systems. Background Technology

[0002] To meet the increased demand for wireless data traffic since the deployment of 4G communication systems, efforts have been made to develop improved 5G or near-5G communication systems. For this reason, 5G or near-5G communication systems are also referred to as "beyond 4G network" communication systems or "post-LTE" systems. The 5G communication systems defined by the 3rd Generation Partnership Project (3GPP) are collectively referred to as New Radio (NR) systems. 5G communication systems are considered to be implemented in ultra-high frequency or millimeter-wave (mmWave) bands (e.g., the 60-GHz band) to achieve high data rates. To reduce path loss and increase coverage in the ultra-high frequency bands used for 5G communication systems, various technologies such as beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO have been researched and applied to NR systems. Furthermore, to improve the system network for 5G communication systems, various technologies have been developed, such as evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multipoint (CoMP), and receive interference cancellation. In addition, for 5G systems, advanced coding and modulation (ACM) technologies such as hybrid frequency shift keying (FSK), quadrature amplitude modulation (QAM) (FQAM), and sliding window superposition coding (SWSC) have been developed, as well as advanced access technologies such as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA).

[0003] The internet has evolved from a human-based network of connections (in which humans generate and consume information) to the Internet of Things (IoT), where distributed elements such as objects exchange information to process it. The Internet of Everything (IoE) technology has emerged, combining IoT technology with technologies for processing big data, such as those connecting to cloud servers. To realize IoT, various technological elements are needed, including sensing technologies, wired / wireless communication and network infrastructure, service interface technologies, and security technologies. In recent years, technologies involving sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC) for connecting objects have been researched. In the IoT environment, intelligent internet technology (IT) services can be provided to collect and analyze data from connected objects to create new value in human life. As existing information technology (IT) integrates with various industries, IoT can be applied to multiple fields, such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0004] Various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies involving sensor networks, M2M communication, and MTC communication are being implemented using 5G communication technologies including beamforming, MIMO, and array antennas. The application of cloud RAN, as a big data processing technology, can serve as an example of the integration of 5G communication technology and IoT technology. Summary of the Invention

[0005] Technical solutions

[0006] According to embodiments of this disclosure, a method performed by a user equipment (UE) in a wireless communication system includes receiving multicast and broadcast service (MBS) information from a base station; identifying an MBS service that the UE expects to receive from the base station based on the MBS information; sending a radio resource control (RRC) connection establishment request message for the identified MBS service to the base station based on a temporary mobile group identity (TMGI) of the identified MBS service included in the MBS information; receiving RRC connection establishment information from the base station; and receiving data corresponding to the identified MBS service from the base station, wherein the TMGI of the identified MBS service includes access category information for controlling access to the base station. Attached Figure Description

[0007] Figure 1 This is a schematic diagram illustrating an operational method for multicast and broadcast service (MBS) communication according to an embodiment of the present disclosure.

[0008] Figure 2 This is a flowchart of a configuration process for performing MBS communication according to an embodiment of the present disclosure.

[0009] Figure 3 This is a flowchart of a method for configuring the cause of a Radio Resource Control (RRC) establishment request according to an embodiment of the present disclosure.

[0010] Figure 4 This is a flowchart of a method for configuring the reason for establishing an RRC request according to an embodiment of this disclosure.

[0011] Figure 5 This is a schematic diagram illustrating a method for configuring a Radio Network Temporary Identifier (RNTI) for performing MBS communication according to embodiments of the present disclosure.

[0012] Figure 6 This is a schematic diagram illustrating a search space configuration method for performing MBS communication according to embodiments of the present disclosure.

[0013] Figure 7 This is a flowchart of a method performed by a user equipment (UE) to request and configure MBS services according to an embodiment of this disclosure.

[0014] Figure 8 This is a block diagram of a base station according to an embodiment of the present disclosure.

[0015] Figure 9 This is a block diagram of a UE according to an embodiment of the present disclosure. Detailed Implementation

[0016] In the following description of this disclosure, detailed descriptions of known functions or configurations included herein will be omitted where such descriptions may obscure the subject matter. Hereinafter, embodiments of this disclosure will be described in detail with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram illustrating an operational method for multicast and broadcast service (MBS) communication according to an embodiment of this disclosure. MBS communication refers to a communication method between a transmitter and multiple receivers in a mobile communication system. In this document, the transmitter may be a base station, and each receiver may be a user equipment (UE). However, the transmitter is not limited to this, and may also be a UE.

[0018] Figure 1 The embodiments illustrate an example of performing MBS communication between a base station 110 acting as a transmitter and UEs 120, 130, 140, and 150 acting as receivers. MBS communication can be broadcast to multiple unspecified receivers or multicast to multiple specific receivers. When communication is performed in a multicast manner, the base station can configure the reception of multicast packets only for specific UEs. For this purpose, a set of UEs can be configured for specific multicast communication, and... Figure 1In the embodiments, such a UE is referred to as multicast group 160.

[0019] UEs in a multicast group can be assigned the same Group-Radio Network Temporary Identifier (G-RNTI) to receive data assigned with the G-RNTI. Figure 1 The embodiment assumes that UE 1 120, UE 2 130, and UE 3 140 are configured as a multicast group and assigned a G-RNTI to receive data from base station 110 via multicast. UE 4 150, which is not included in the multicast group and is not assigned a G-RNTI, may not receive data received from the base station by UE 1 120, UE 2 130, and UE 3 140.

[0020] One or more multicast groups can be configured within the coverage area of ​​base station 110, and each multicast group can be identified by a G-RNTI. A UE can be assigned one or more G-RNTIs from base station 110. Using the G-RNTI value assigned in RRC connected mode, the UE can receive multicast data in RRC idle mode, RRC inactive mode, and RRC connected mode. In the UE's RRC connected mode, the G-RNTI can be included and configured in at least one of the RRC reconfiguration message, RRC establishment message, and RRC reconstruction message. However, the G-RNTI is not limited to this and can be included in the System Information Block (SIB) as a UE-receiveable G-RNTI value and sent from the base station. A UE that has already been assigned a G-RNTI value can subsequently apply the G-RNTI.

[0021] Figure 2 This is a flowchart of a configuration process for performing MBS communication according to an embodiment of this disclosure. A UE 220 without an RRC connection to base station 210 can select a base station to request MBS service to perform MBS communication. In this case, UE 220 can perform a cell selection or reselection process to receive a synchronization signal transmitted from the base station and select a base station corresponding to the highest received power (operation 230). Figure 2 The implementation example assumes that a UE that has transitioned from the initial RRC connected mode to the RRC idle mode or the RRC inactive mode performs a cell reselection operation to select a cell.

[0022] Subsequently, UE 220 can receive an SIB from the selected cell (operation 235). In this case, when UE 220 expects to receive MBS services, UE 220 can receive an SIB that includes MBS information in the SIBS. The SIB including MBS information can include a list of MBS services that are already provided or available from each serving cell.

[0023] The list of MBS services that have been provided or are available from each serving cell can be called the AvailableMBSList. The AvailableMBSList may include MBS session information. MBS session information may include a Temporary Mobile Group Identifier (TMGI) value for identifying the group and an MB session ID value. Each TMGI value may include a Public Land Mobile Network ID (plmn-id) for identifying the mobile operator, and a Service ID for identifying the service provided by the mobile operator. When the above types of information are combined, the AvailableMBSList can have the structure shown in the example below.

[0024] -AvailableMBSList=MBSSessionInfoList

[0025] ■A sequence of MBSSessionInfoList = (tmgi, sessionID)

[0026] ◆tmgi=(plmn-id,serviceID)

[0027] When all UEs request RRC configuration to receive all MBS services, the base station may become overloaded due to the transient access of many UEs. Therefore, access control for MBS services may be necessary. For this purpose, an access class value and uac-BarringForAccessIdentity for access control can be configured in each TMGI. Using the access class and uac-BarringForAccessIdentity configured as described above, the number of access requests to the base station can be controlled for each TMGI. Although Figure 2 The embodiment assumes that UE 220 receives an SIB that includes MBS information. The MBS information is not limited to this and may be included in the downlink (DL) information transmission message.

[0028] Having received the SIB containing MBS information, UE 220 can identify the MBS service of interest from the list of MBS services already provided or available in each serving cell (Operation 240). UE 220 can determine which MBS service it is interested in based on the MBS service required by its application or other conditions. UE 220 can identify the MBS service based on the TMGI. That is, UE 220 can check whether the TMGI of the MBS service that UE 220 expects to receive (or is interested in) is included in the SIB containing MBS information. Specifically, UE 220 can check whether the TMGI of the MBS service that UE 220 expects to receive is included in the AvailableMBSList of the SIB containing MBS information. When the TMGI of the MBS service that UE 220 expects to receive is included in the SIB containing MBS information, UE 220 can perform RRC connection establishment to receive the MBS service.

[0029] In this scenario, to determine whether to initiate RRC connection establishment, UE 220 can perform access control (operation 245). Based on the plmn-ID included in the TMGI of the MBS service to be received, UE 220 can perform access control by using unified access control (UAC) – Barring information for the plmn-ID. It can be determined whether access is allowed for the UAC-BarringForAccessIdentity and the access category of the MBS service that UE 220 expects to receive. When access for the MBS service is allowed, UE 220 can initiate the RRC connection request procedure.

[0030] When UE 220 is allowed to access and receive MBS service, UE 220 may send an RRC establishment request message (operation 250) to base station 210. However, this message is not limited to this, and an RRC reconstruction request message can also be used for the same purpose as the RRC establishment request message. The RRC establishment request message or the RRC reconstruction request message is a generic message that can be used for UE 220 to switch to RRC connection mode, and therefore may include a reason value indicating the purpose for which UE 220 expects to switch to RRC connection mode. In this case, when UE 220 expects to receive MBS service, UE 220 may send an RRC establishment request message or an RRC reconstruction request message to base station 210 including the MBS configuration as the reason value. However, when the RRC establishment request message or the RRC reconstruction request message is not for receiving MBS service, UE 220 may send the RRC establishment request message or the RRC reconstruction request message using a reason value sent from a higher layer.

[0031] Base station 210 can send an RRC establishment message to UE 220 to switch UE 220 to RRC connection mode (operation 260). However, this message is not limited to this, and an RRC reconstruction message can also be used for the same purpose as the RRC establishment message. When UE 220 receives an RRC establishment message or an RRC reconstruction message, it can configure signaling radio bearer 1 (SRB1) based on the SRB1 configuration information included in the received message. SRB1 can be a radio bearer used to exchange RRC messages between base station 210 and UE 220.

[0032] UE 220 can apply the configuration information included in the RRC establishment message or RRC reconstruction message and send an RRC establishment completion message or RRC reconstruction completion message to base station 210 to indicate successful application of the configuration received from base station 210 (operation 265). Furthermore, the RRC establishment completion message or RRC reconstruction completion message sent in operation 265 may include a list of MBS services that UE 220 expects to receive. The MBS service list may be a list including TMGI values ​​corresponding to the MBS services that UE 220 expects to receive. In this case, the TMGIs including the MBS service list may include all or some of the TMGIs included in the list of MBS services already provided or available from each serving cell, which are included in the SIB or DL ​​information transfer message sent from base station 210 in operation 235.

[0033] In operation 265, because SRB1 is configured and a list of MBS services that UE 220 expects to receive is provided to base station 210, base station 210 can configure the reception of MBS services for UE 220 based on the received information. MBS services can be configured using an RRC reconfiguration message sent from base station 210 to UE 220 (operation 270). The RRC reconfiguration message may include, for example, configuration information for signaling radio bearer 2 (SRB2) for sending or receiving non-access stratum (NAS) messages, data radio bearer (DRB) for sending or receiving data, and point-to-multipoint (PTM) DRB for multicast transmission. In this document, PTM DRBs can be configured without distinguishing them from ordinary DRBs, or via a received G-RNTI. Furthermore, radio link control (RLC) bearers for sending configuration radio bearers can be configured, as can radio bearers connected to RLC bearers. In this document, G-RNTIs for receiving multicast data by UEs belonging to multicast groups can also be configured. G-RNTI is an RNTI configured to receive Transport Blocks (TBs) and can be used for scheduling information addressing Physical Downlink Shared Channels (PDSCH). G-RNTI can be configured by Media Access Control (MAC) entity or by Bandwidth Part (BWP). When configuring G-RNTI by BWP, the configured G-RNTI can be used only for receiving the PDSCH resources of the BWP. That is, the G-RNTI may not be used for other BWPs. For this reason, the G-RNTI can be included and configured in the BWP-Downlink configuration field of the RRC message. The BWPID to be used for configuring the G-RNTI can also be configured. In another embodiment, G-RNTI can be configured by cell. When configuring G-RNTI by cell, the configured G-RNTI can be used only for receiving the PDSCH resources of the receiving cell. That is, the G-RNTI may not be used for other cells. For this reason, the G-RNTI can be included and configured in the cell configuration field of the RRC message. The cell ID to be used for configuring the G-RNTI can also be configured.

[0034] The BWP and search space can be configured to receive MBS services. Configuration information for the BWP and search space used to receive a specific MBS service can be transmitted from base station 210 to UE 220, and the MBS BWP and MBS search space can be included in the configuration information. In this document, MBS BWP can refer to a BWP with an assigned G-RNTI applied. According to an embodiment, a BWP configured by the BWP-downlink configuration field including the G-RNTI can be an MBS BWP. The MBS search space can be a search space configured by search space configuration information including downlink control information (DCI) format for MBS reception, or a search space configured by search space configuration information including a search space indicator for MBS reception. For example, the search space configuration information can include a 1-bit indicator indicating whether the search space is an MBS search space. When the indicator indicates an MBS search space, the search space can be an MBS search space, used as a search space for monitoring the G-RNTI for MBS reception.

[0035] When UE 220 applies information included in the RRC reconfiguration message of operation 270, UE 220 can send an RRC reconfiguration complete message to base station 210 to inform it that the RRC reconfiguration message information has been applied (operation 275). In this way, UE 220 can receive broadcast or multicast packets by performing MBS communication. That is, UE 220 can receive MBS service from base station 210 (operation 280).

[0036] Figure 3This is a flowchart of a method for configuring the reason for an RRC establishment request according to an embodiment of this disclosure. When a UE is allowed to access and receive MBS services, the UE can send an RRC establishment request message to the base station. However, the message is not limited to this, and an RRC reconstruction request message can also be used for the same purpose as the RRC establishment request message. The RRC establishment request message or the RRC reconstruction request message is a general message that can be used by a UE to switch to RRC connection mode, and therefore can include a reason value indicating the purpose for which the UE expects to switch to RRC connection mode. As described above, when an RRC establishment request message or an RRC reconstruction request message is triggered (operation 310), the UE can check the reason for triggering the message (operation 320). When the message is not an RRC establishment request message or an RRC reconstruction request message for MBS reception, the UE can send the RRC establishment request message or the RRC reconstruction request message by using an establishment reason sent from a higher layer (operation 330). When the message is an RRC establishment request message or an RRC reconstruction request message for MBS reception, the UE can send the message by using MBS reception as the establishment reason (operation 340). Using the reason value configured as described above, the base station can know the purpose of the UE's desired transition to RRC connection mode and subsequently send an appropriate configuration message.

[0037] Figure 4This is a flowchart of a method for configuring the reason for an RRC establishment request according to an embodiment of this disclosure. When a UE is allowed to access and receive MBS services, the UE can send an RRC establishment request message to the base station. However, the message is not limited to this, and an RRC reconstruction request message can also be used for the same purpose as the RRC establishment request message. The RRC establishment request message or the RRC reconstruction request message is a general message that can be used by a UE to switch to RRC connection mode, and therefore can include a reason value indicating the purpose for which the UE expects to switch to RRC connection mode. As described above, when an RRC establishment request message or an RRC reconstruction request message is triggered (operation 410), the UE can check the reason for triggering the message (operation 420). When the message is not an RRC establishment request message or an RRC reconstruction request message for MBS reception but a request from a higher layer, the UE can send the RRC establishment request message or the RRC reconstruction request message using the establishment reason sent from the higher layer (operation 430). When the message is an RRC establishment request message or an RRC reconstruction request message for MBS reception but not a request from a higher layer, the UE can send the message using MBS reception as the establishment reason (operation 440). As described above, the UE initially checks whether the RRC establishment request message or RRC reconstruction request message is based on a request from a higher layer. If the message is based on a request from a higher layer, it sends the message using the establishment reason sent from the higher layer. If the RRC establishment request message or RRC reconstruction request message is not based on a request from a higher layer, the UE can check whether the message is for MBS reception and send the message using MBS reception as the establishment reason. Using the reason value configured as described above, the base station can know the UE's intended purpose for switching to RRC connection mode and subsequently send an appropriate configuration message.

[0038] Figure 5 This is a schematic diagram illustrating an RNTI configuration method for performing MBS communication according to embodiments of the present disclosure. An RNTI is an identifier configured for a UE to send, receive, or both send and receive data, and multiple RNTIs can be configured for a single UE. RNTIs can be configured for different purposes. RNTIs can include cell-RNTIs (C-RNTIs), configured scheduling-RNTIs (CS-RNTIs), and group-RNTIs (G-RNTIs). RNTIs can have three types.

[0039] The first RNTI 510 refers to the RNTI related to the transmission and reception of a TB. RNTIs belonging to the first RNTI 510 are used to address scheduling information for the PDSCH or Physical Uplink Shared Channel (PUSCH). That is, resources allocated with the first RNTI 510 refer to TB resources mapped to PDSCH or PUSCH resources. The first RNTI 510 can be allocated by MAC entity or cell group. In other words, when the first RNTI 510 is allocated, it means that the first RNTI 510 is applied to the corresponding MAC entity or the corresponding cell group. Therefore, the first RNTI 510 can be included and configured in PhysicalCellGroupConfig. CS-RNTI, C-RNTI, and Modulation and Coding Scheme-C-RNTI (MCS-C-RNTI) can belong to the first RNTI 510.

[0040] The second RNTI 520 refers to the RNTI related to Transmit Power Control (TPC). RNTIs belonging to the second RNTI 520 are used to receive TPC commands for the Sound Reference Signal (SRS), Physical Uplink Control Channel (PUCCH), or PUSCH. The second RNTI 520 can be assigned by MAC entity or cell group. That is, when a second RNTI 520 is assigned, it means that the second RNTI 520 is applied to the corresponding MAC entity or the corresponding cell group. For this purpose, the second RNTI 520 can be included and configured in PhysicalCellGroupConfig. TPC-SRS-RNTI, TPC-PUCCH-RNTI, and TPC-PUSCH-RNTI can belong to the second RNTI 520.

[0041] The third RNTI 530 refers to the RNTI associated with TB reception. RNTIs belonging to the third RNTI 530 are used to address PDSCH scheduling information. That is, resources allocated with the third RNTI 530 refer to TB resources mapped to PDSCH resources. The third RNTI 530 can be allocated to a specific BWP or a specific cell. In other words, when the third RNTI 530 is allocated, it means that the third RNTI 530 is applied to the corresponding BWP or the corresponding cell. When allocated to a specific BWP, the third RNTI 530 can be included in the BWP-downlink configuration and sent to the UE for configuration. G-RNTIs can belong to the third RNTI 530.

[0042] According to another embodiment, the third RNTI 530 can be an RNTI related to the transmission and reception of a TB. In this case, the RNTI belonging to the third RNTI 530 is used to address scheduling information for the PDSCH or PUSCH. That is, the resource allocated with the third RNTI 530 refers to the TB resource mapped to the PDSCH or PUSCH resource. The third RNTI 530 can be allocated to a specific BWP or a specific cell. That is, when the third RNTI 530 is allocated, it means that the third RNTI 530 is applied to the corresponding BWP or the corresponding cell. When allocated to a specific BWP, the third RNTI 530 can be included in the BWP-downlink configuration or the BWP-uplink configuration and sent to the UE and configured for the UE. The G-RNTI can belong to the third RNTI 530.

[0043] Figure 6 This is a schematic diagram illustrating a search space configuration method for performing MBS communication according to embodiments of the present disclosure. A Base Window (BWP) and a search space can be configured to receive MBS services. Configuration information for the BWP and search space used to receive a specific MBS service can be sent from the base station to the UE, and the MBS BWP and MBS search space can be included in the configuration information. In this document, an MBS BWP may refer to a BWP with an assigned G-RNTI applied. According to an embodiment, a BWP configured by a BWP-downlink configuration field including a G-RNTI can be an MBS BWP. In another embodiment, when a G-RNTI is assigned, the ID of the BWP with the applied G-RNTI can be included to configure the MBS BWP. The MBS search space can be a search space configured by search space configuration information in DCI format for MBS reception, or a search space configuration information including a search space indicator for MBS reception. For example, the search space configuration information may include a 1-bit indicator indicating whether the search space is an MBS search space. When the indicator specifies an MBS search space, this search space can be an MBS search space used for monitoring G-RNTI for MBS reception. A search space refers to the radio resources in which the UE monitors the configured RNTI. Various types of search spaces can exist within the search space defined in the active BWP. Search spaces can be configured for different purposes. There are three types of search spaces.

[0044] The first search space 610 can be a search space configured as a UE-specific search space (USS) from the search space associated with the currently active BWP. The first search space 610 is for a specific UE, and each UE can check the allocated resources by checking the RNTI configured for the first search space 610 within the first search space 610.

[0045] The second search space 620 can be a search space configured as a common search space (CSS) from the search space associated with the currently active BWP. The second search space 620 is a dynamically scheduled search space shared by multiple UEs or all UEs to receive system information or paging messages. However, for resource management purposes, the second search space 620 can also be used by a specific UE. Each UE can check the allocated resources by checking the RNTI configured for the second search space 620 within the second search space 620.

[0046] The third search space 630 is a search space applied to MBS communication and can be an MBS search space from the search space associated with the currently active BWP. When the active BWP is a BWP with an RNTI configured for the third search space 630, each UE can check the allocated resources by checking the RNTI configured for the third search space 630 within the third search space 630. According to an embodiment, the RNTI configured for the third search space 630 can be a G-RNTI. When the RNTI configured for the third search space 630 is not an RNTI configured for a specific BWP or a specific cell, the UE can check the allocated resources by always checking the RNTI configured for the third search space 630 within the third search space 630.

[0047] Figure 7 This is a flowchart illustrating a method performed by UE 720 to request and configure MBS services according to an embodiment of this disclosure. When UE 720 expects to receive MBS services, UE 720 may request base station 710 to confirm whether the serving cell of base station 710 has provided or can provide MBS services. When UE 720 does not receive a list of MBS services that base station 710 is providing or can provide from base station 710, or when the MBS service that UE 720 expects to receive is not included in the list, UE 720 may request confirmation as described above.

[0048] To this end, UE 720 may send a TMGI check request message to base station 710 to request confirmation that the TMGI of the MBS service that UE 720 expects to receive or is interested in is a TMGI of a service that base station 710 is providing or can provide (operation 730). The TMGI check request message may include the TMGI of the MBS service that UE 720 expects to receive, the TMGI of the MBS service that UE 720 is interested in, or the TMGI of the MBS service that UE 720 requests confirmation of whether it is a TMGI of an MBS service that base station 710's serving cell is providing or can provide.

[0049] Upon receiving a TMGI check request message, base station 710 can send a TMGI of the MBS service that is provided or available to UE 720 using the TMGI check message (operation 740). The TMGI check message may include a TMGI of the MBS service that is being provided or available from the serving cell of base station 710, derived from the TMGI included in the TMGI check request message sent from UE 720 in operation 730. In another embodiment, regardless of the information included in the TMGI check request message of operation 730, a TMGI of the MBS service that is currently being provided or available from the serving cell of base station 710 can be sent to UE 720. Upon receiving the TMGI check message of operation 740, UE 720 can know the MBS service served by the serving cell of base station 710.

[0050] In another embodiment, the operation based on the TMGI check request message can also be performed based on an on-demand system information request message. In this case, the on-demand system information request message can be an SIB request including information about MBS services being provided or available from the serving cell of base station 710. Upon receiving the on-demand system information request message, base station 710 can send an SIB including MBS information instead of a TMGI check message (operation 740).

[0051] The list of MBS services that are already being provided or are available from each serving cell can be referred to as the AvailableMBSList. The AvailableMBSList may include MBS session information. MBS session information may include a TMGI value for identifying the group and an MBS sessionID value. Each TMGI value may include a plmn-id for identifying the mobile operator and a serviceID for identifying the service provided by the mobile operator. When the above types of information are combined, the AvailableMBSList can have the structure shown in the example below.

[0052] -AvailableMBSList=MBSSessionInfoList

[0053] ■A sequence of MBSSessionInfoList = (tmgi, sessionID)

[0054] ◆tmgi=(plmn-id,serviceID)

[0055] Subsequently, UE 720 may send an MBS service request message to base station 710 to request the MBS services that UE 720 actually expects to receive (Operation 750). In this case, UE 720 may send an MBS service request message that includes a list of MBS services that UE 720 actually expects to receive. The MBS service list may be a list that includes TMGI values ​​corresponding to the MBS services that UE 720 expects to receive. In this case, the included TMGIs may include all or some of the TMGIs included in the list of MBS services that are already being provided or are available from each serving cell, which are obtained by UE 720 in Operation 740.

[0056] Based on the MBS service request message of Operation 750, base station 710 can send an MBS service configuration message to UE 720 to configure MBS service reception (Operation 760). MBS service can be configured using an RRC reconfiguration message sent from base station 710 to UE 720. The MBS service configuration message can also configure a G-RNTI for allowing UEs belonging to a multicast group to receive multicast data. The G-RNTI is an RNTI configured to receive TBs and can be used for scheduling information addressing PDSCHs. The G-RNTI can be configured per MAC entity or per BWP. When configuring the G-RNTI per BWP, the configured G-RNTI can be used only for receiving PDSCH resources of the BWP. That is, the G-RNTI may not be used for other BWPs. For this purpose, the G-RNTI can be included and configured in the BWP-Downlink Configuration field of the RRC message. A BWP ID for configuring the G-RNTI can also be configured. In another embodiment, the G-RNTI can be configured per cell. When configuring G-RNTI per cell, the configured G-RNTI can be used only for the PDSCH resources of the receiving cell. That is, the G-RNTI does not need to be used for other cells. Therefore, the G-RNTI can be included and configured in the cell configuration field of the RRC message. Alternatively, the cell ID used to configure the G-RNTI can also be configured.

[0057] The BWP and search space can be configured to receive MBS services. Configuration information for the BWP and search space used to receive a specific MBS service can be transmitted from base station 710 to UE 720, and the MBS BWP and MBS search space can be included in the configuration information. In this document, MBS BWP may refer to a BWP with an assigned G-RNTI applied. According to an embodiment, a BWP configured by the BWP-downlink configuration field including the G-RNTI can be an MBS BWP. The MBS search space can be a search space configured by search space configuration information in DCI format for MBS reception, or a search space configuration information configured by search space configuration information including an indicator for the search space used for MBS reception. For example, the search space configuration information may include a 1-bit indicator indicating whether the search space is an MBS search space. When the indicator indicates an MBS search space, the search space can be an MBS search space, used as a search space for monitoring the G-RNTI for MBS reception.

[0058] Figure 8 This is a block diagram of a base station according to an embodiment of the present disclosure.

[0059] Reference Figure 8 The base station may include a transceiver 810, a controller 820, and a memory 830. In this disclosure, the controller 820 may be defined as a circuit or an application-specific integrated circuit or at least one processor.

[0060] Transceiver 810 can send signals to or receive signals from other network entities. Transceiver 810 can send system information, synchronization signals, or reference signals to, for example, a UE.

[0061] According to embodiments of this disclosure, controller 820 can control the overall operation of the base station. For example, controller 820 can control the signal flow between blocks to perform operations based on the flowchart described above.

[0062] The memory 830 can store at least one of the information sent or received by the transceiver 810 and the information generated by the controller 820.

[0063] Figure 9 This is a block diagram of a UE according to an embodiment of the present disclosure.

[0064] Reference Figure 9 The UE may include a transceiver 910, a controller 920, and a memory 930. In this disclosure, the controller 920 may be defined as a circuit or an application-specific integrated circuit or at least one processor.

[0065] Transceiver 910 can send signals to or receive signals from other network entities. Transceiver 910 can receive system information, synchronization signals, or reference signals from, for example, a base station.

[0066] According to embodiments of this disclosure, controller 920 can control the overall operation of the UE. For example, controller 920 can control the signal flow between blocks to perform operations based on the flowchart described above.

[0067] The memory 930 can store at least one of the information sent or received by the transceiver 910 and the information generated by the controller 920.

[0068] The embodiments disclosed in this specification and accompanying drawings are merely for the purpose of describing the technical content of this disclosure and promoting understanding of this disclosure, and do not limit the scope of this disclosure. That is, those skilled in the art will understand that the embodiments can be modified in various ways without departing from the scope of this disclosure. These embodiments can be combined to implement as needed.

Claims

1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: The base station receives a Radio Resource Control (RRC) reconfiguration message including information indicating a Group-Radio Network Temporary Identifier (G-RNTI) for multicast and broadcast services MBS, wherein the RRC reconfiguration message includes information indicating a Bandwidth Part (BWP) configured for the MBS and search space information associated with the MBS, and the search space information is associated with the BWP. Based on G-RNTI and the search space information associated with the BWP, the scheduling information of the Physical Downlink Shared Channel (PDSCH) associated with the MBS is identified; and Based on scheduling information, downlink data associated with MBS is received from the base station via PDSCH.

2. The method according to claim 1, wherein, The RRC reconfiguration message also includes information associated with the radio bearer used for MBS.

3. The method according to claim 1, wherein, The search space information is used to monitor the scheduling information of the PDSCH associated with MBS.

4. The method according to claim 3, wherein, The search space information is associated with at least one downlink control information DCI format of MBS.

5. The method according to claim 1, wherein, G-RNTI is configured for cell groups.

6. The method according to claim 1, further comprising: Based on the RRC reconfiguration message, an RRC reconfiguration complete message is sent to the base station.

7. A method performed by a base station in a wireless communication system, the method comprising: Send a Radio Resource Control (RRC) reconfiguration message to the User Equipment (UE) including information indicating a Group-Radio Network Temporary Identifier (G-RNTI) for Multicast and Broadcast Services (MBS), wherein the RRC reconfiguration message includes information indicating a Bandwidth Part (BWP) configured for the MBS and search space information associated with the MBS, and the search space information is associated with the BWP. Send scheduling information for the Physical Downlink Shared Channel (PDSCH) associated with the MBS to the UE, wherein the scheduling information is associated with the G-RNTI and the search space information associated with the BWP; and Based on scheduling information, downlink data associated with MBS is sent to the UE via PDSCH.

8. The method according to claim 7, wherein, The RRC reconfiguration message also includes information associated with the radio bearer used for MBS.

9. The method according to claim 7, wherein, The search space information is used to monitor the scheduling information of the PDSCH associated with MBS.

10. The method according to claim 9, wherein, The search space information is associated with at least one downlink control information DCI format of MBS.

11. The method according to claim 7, wherein, G-RNTI is configured for cell groups.

12. The method of claim 7, further comprising: Based on the RRC reconfiguration message, receive the RRC reconfiguration complete message from the UE.

13. A user equipment (UE) in a wireless communication system, the UE comprising: transceiver; and At least one processor, coupled to the transceiver, is configured to: The radio resource control (RRC) reconfiguration message is received from the base station via a transceiver. It includes information indicating the group-radio network temporary identifier (G-RNTI) for multicast and broadcast services (MBS). The RRC reconfiguration message includes information indicating the bandwidth portion (BWP) configured for the MBS and search space information associated with the MBS, and the search space information is associated with the BWP. Based on G-RNTI and the search space information associated with the BWP, the scheduling information of the Physical Downlink Shared Channel (PDSCH) associated with MBS is identified. and Based on scheduling information, downlink data associated with MBS is received from the base station via transceiver and PDSCH.

Images