Method and apparatus for supporting mbs in a wireless communication system

Abstract

A method performed by a user equipment (UE) in a wireless communication system is provided. The method includes receiving configuration information about a multicast broadcast service (MBS), receiving MBS data in a radio resource control (RRC)_Connected mode based on the configuration information, and wherein the MBS data is transmitted to a plurality of UEs including the UE for a multicast transmission, or to the UE for a unicast transmission, and wherein a hybrid automatic repeat request (HARQ) retransmission is applied to the transmission of the MBS data.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a method and apparatus for supporting a multicast or unicast supporting bearer structure in a next-generation mobile communication system. BACKGROUND

[0002] To meet increasing demand with respect to wireless data traffic after commercialization of 4th generation (4G) communication systems, efforts have been made to develop an advanced 5th generation (5G) or pre-5G communication system. Therefore, the 5G communication system or the pre-5G communication system is also called a beyond 4G network or a post long term evolution (LTE) system. To achieve a high data transmission rate, implementation of the 5G communication system in a frequency band of ultra-high frequency (mmWave), e.g., 60 GHz band, has been considered. To mitigate propagation loss of radio waves and increase a transmission distance of the radio waves in the ultra-high frequency band, technologies such as beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large scale antennas have been discussed in the 5G communication system. In addition, to improve network of the system, technologies such as advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving networks, cooperative communication, coordinated multi-points (CoMP), and reception interference cancellation have been developed in the 5G communication system. Also, an advanced coding modulation (ACM) scheme (i.e., hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) (FQAM) and sliding window superposition coding (SWSC)) and an advanced access technology (i.e., filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA)) have been developed in the 5G communication system.

[0003] Meanwhile, the Internet is evolving from the human-centered connection network in which humans generate and consume information to an Internet of Things (IoT) network in which distributed entities or things transmit, receive, and process information. An Internet of Everything (IoE) technology, in which a big data processing technology and the like based on a connection with a cloud server or the like is combined with the IoT technology, has also emerged. To implement the IoT, technical elements such as a sensing technology, wired / wireless communication and network infrastructure, a service interface technology, and a security technology are required, and therefore, a technology for connection between things such as a sensing network, a machine-to-machine (M2M) communication, machine type communication (MTC), and the like has recently been researched. In the IoT environment, an intelligent Internet technology (IT) service for a new value creation in that data generated by connected things is collected and analyzed can be provided. The IoT can be applied to fields such as a smart home, a smart building, a smart city, a smart car or connected cars, a smart grid, health care, a smart home appliance, and an advanced medical service based on convergence and combination between the existing information technology (IT) and various industries.

[0004] Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as sensor networks, M2M communication, MTC, etc. have been implemented based on 5G communication techniques such as beamforming, MIMO, array antennas, etc. As described above, the cloud RAN can be applied because big data processing technology can also be considered as an example of convergence of the 5G technology and the IoT technology.

[0005] As described above, as the wireless communication system evolves, various services can be provided, and thus, a method of seamlessly providing services is required. Specifically, a structure or a configuration method for supporting a multicast bearer or a unicast bearer for a multicast or broadcast service (MBS) is required, and a data processing method of a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, or a packet data convergence protocol (PDCP) layer configured to receive and process MBS data is required. In addition, in order to support the MBS according to handover between base stations supporting the MBS or between networks or according to mobility of a terminal, a method of reconfiguring (or switching) a multicast bearer to a unicast bearer or reconfiguring (or switching) a unicast bearer to a multicast bearer is required.

[0006] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure. SUMMARY

[0007] In the next-generation mobile communication system, in order to support services such as a broadcast / multicast service, a mission critical service, or a public safety service, a multicast or broadcast service (MBS), a multimedia broadcast and multicast service (MBMS), or a multicast and broadcast service can be supported. The MBS can provide services to terminals via a multicast bearer or a unicast bearer.

[0008] In order to support the MBS, a structure or a configuration method for supporting a multicast bearer or a unicast bearer for the MBS, and a data processing method of a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, or a packet data convergence protocol (PDCP) layer configured to receive and process MBS data are required.

[0009] In addition, a signaling procedure or operation of a terminal must also be specified in order to continuously support the MBS in a radio resource control (RRC) connected mode, an RRC idle mode, or an RRC inactive mode, or during transition between the modes.

[0010] Further, in order to support MBS according to handover between base stations supporting MBS or between networks or according to mobility of a terminal, a method of reconfiguring (or switching) a multicast bearer to a unicast bearer or reconfiguring (or switching) a unicast bearer to a multicast bearer is required.

[0011] Aspects of the disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the disclosure is to provide a method performed by a terminal to normally receive an MBS in the above-described various cases.

[0012] According to an aspect of the disclosure, a method performed by a user equipment (UE) in a wireless communication system includes receiving configuration information about a multicast broadcast service (MBS), receiving MBS data in a radio resource control (RRC)_Connected mode based on the configuration information, and wherein the MBS data is transmitted to a plurality of UEs including the UE for multicast transmission, or to the UE for unicast transmission, and wherein hybrid automatic repeat request (HARQ) retransmission is applied to transmission of the MBS data.

[0013] A bearer of the MBS includes a service data adaptation protocol (SDAP) entity and a packet data convergence protocol (PDCP) entity.

[0014] The PDCP entity provides a header compression function by using robust header compression (ROHC) and a PDCP reordering function.

[0015] A bearer of the MBS includes at least one of a radio link control (RLC) acknowledged mode (AM) or a RLC unacknowledged mode (UM) for dynamic switching between unicast transmission and multicast transmission.

[0016] The MBS data is scheduled by using a cell radio network temporary identifier (C-RNTI) for unicast transmission and an MBS-RNTI for multicast transmission.

[0017] According to another aspect of the disclosure, a method performed by a base station in a wireless communication system includes transmitting, to a user equipment (UE), configuration information about a multicast broadcast service (MBS), transmitting MBS data in a radio resource control (RRC)_Connected mode based on the configuration information, and wherein the MBS data is transmitted to a plurality of UEs including the UE for multicast transmission, or to the UE for unicast transmission, and wherein hybrid automatic repeat request (HARQ) retransmission is applied to transmission of the MBS data.

[0018] According to an aspect of the disclosure, a user equipment (UE) in a wireless communication system, the UE comprising: a transceiver; and at least one processor connected with the transceiver and configured to: receive configuration information on a multicast broadcast service (MBS); receive MBS data in a radio resource control (RRC)_Connected mode based on the configuration information; and wherein the MBS data is transmitted to a plurality of UEs including the UE for a multicast transmission, or to the UE for a unicast transmission, and wherein a hybrid automatic repeat request (HARQ) retransmission is applied to the transmission of the MBS data.

[0019] According to an aspect of the disclosure, a base station in a wireless communication system, the base station comprising: a transceiver; and at least one processor connected with the transceiver and configured to: transmit configuration information on a multicast broadcast service (MBS) to a user equipment (UE); transmit MBS data in a radio resource control (RRC)_Connected mode based on the configuration information; and wherein the MBS data is transmitted to a plurality of UEs including the UE for a multicast transmission, or to the UE for a unicast transmission, and wherein a hybrid automatic repeat request (HARQ) retransmission is applied to the transmission of the MBS data.

[0020] Other aspects will be apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the disclosure.

[0021] Other aspects, advantages, and salient features of the disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, various embodiments of the disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0023] FIG. 1A is a diagram of a structure of a long term evolution (LTE) system according to an embodiment of the disclosure;

[0024] FIG. 1B is a diagram of a radio protocol architecture of an LTE system according to an embodiment of the disclosure;

[0025] FIG. 1C is a diagram of an architecture of a next generation mobile communication system according to an embodiment of the disclosure;

[0026] FIG. 1D is a diagram of a radio protocol architecture of a next generation mobile communication system according to an embodiment of the disclosure;

[0027] FIG. 1Eis a diagram of a procedure of providing a service to a terminal by efficiently using a large frequency bandwidth in a next-generation mobile communication system according to an embodiment of the disclosure;

[0028] FIG. 1F shows a diagram of a procedure of a terminal transitioning from a radio resource control (RRC) idle mode to an RRC connected mode in a next-generation mobile communication system according to an embodiment of the disclosure, and a method of configuring a plurality of bandwidth parts (BWPs) and configuring a default BWP or a first active BWP;

[0029] FIG. 1G is a diagram of a structure of a bearer established when a base station or a network configures an MBS by using a system information, an RRC message, or a control message of an MBS channel to support a multicast or broadcast service (MBS) of a terminal in an RRC connected mode, an RRC inactive mode, or an RRC idle mode, or a structure of a bearer established for a terminal to receive an MBS according to an embodiment of the disclosure;

[0030] FIG. 1H is a diagram of a method of demultiplexing received MBS data via a medium access control (MAC) layer when a terminal in an RRC connected mode, an RRC inactive mode, or an RRC idle mode receives the MBS data (e.g., MBS control data, MBS user data, or general data other than MBS data) via a multicast bearer or a unicast bearer supporting an MBS according to an embodiment of the disclosure;

[0031] FIG. 1I is a diagram of a method of multiplexing MBS data to be transmitted via a MAC entity when a terminal in an RRC connected mode, an RRC inactive mode, or an RRC idle mode transmits the MBS data (e.g., MBS control data, MBS user data, or general data other than MBS data) via a multicast bearer or a unicast bearer supporting an MBS according to an embodiment of the disclosure;

[0032] FIG. 1J is a diagram of a first signaling procedure supporting an MBS according to an embodiment of the disclosure;

[0033] FIG. 1K is a diagram of a second signaling procedure supporting an MBS according to an embodiment of the disclosure;

[0034] FIG. 1L is a diagram of a third signaling procedure supporting an MBS according to an embodiment of the disclosure;

[0035] FIG. 1M is a diagram of a fourth signaling procedure supporting an MBS according to an embodiment of the disclosure;

[0036] FIG. 1Nis a diagram of a case in which general data and MBS data collide or overlap with each other when a terminal receives a general data service and an MBS in an RRC connected mode according to an embodiment of the disclosure;

[0037] FIG. 1O is a diagram of a signaling procedure for efficiently supporting an MBS according to an embodiment of the disclosure;

[0038] FIG. 1P is a diagram of a method of indicating each of a plurality of MBSs according to an embodiment of the disclosure;

[0039] FIG. 1Q is a diagram of a method of retransmitting MBS data according to an embodiment of the disclosure;

[0040] FIG. 1R is a diagram of a first handover method or a second handover method in a method of supporting an MBS proposed in a next-generation mobile communication system or an access stratum (AS), in which the first handover method involves continuously supporting (transmitting or receiving) the MBS by switching a multicast service or a multicast bearer to a unicast service or a unicast bearer, and the second handover method involves continuously supporting (transmitting or receiving) the MBS by switching a unicast service or a unicast bearer to a multicast service or a multicast bearer, according to an embodiment of the disclosure;

[0041] FIG. 1S is a diagram of an operation of a terminal according to an embodiment of the disclosure;

[0042] FIG. 1T is a diagram of a structure of a terminal according to an embodiment of the disclosure; and

[0043] FIG. 1U is a block diagram of a Tx / Rx point (TRP) according to an embodiment of the disclosure.

[0044] In all the drawings, like reference numerals will be understood to refer to like parts, components, and structures. DETAILED DESCRIPTION

[0045] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be taken as illustrations only. Accordingly, one of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions can be omitted for clarity and conciseness.

[0046] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used to enable a clear and complete understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for limiting the present disclosure as defined by the appended claims and their equivalents.

[0047] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0048] Throughout the present disclosure, the expression "at least one of a, b or c" indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or a variation thereof.

[0049] Examples of a terminal can include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, a multimedia system capable of performing a communication function, etc.

[0050] In the present disclosure, a controller can also be referred to as a processor.

[0051] Throughout the specification, a layer (or a layer device) can also be referred to as an entity.

[0052] In describing the present disclosure, when a detailed description of related known functions or configurations is determined to be unnecessary for the understanding of the present disclosure, a detailed description thereof can be omitted. Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0053] For the convenience of description, terms identifying access nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various kinds of identification information, etc. are illustrative. Accordingly, the present disclosure is not limited to the terms to be described later, and other terms referring to entities having equivalent technical meanings can also be used.

[0054] For the convenience of description, terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard are used herein. However, the present disclosure is not limited by these terms and names, and can be equally applied to systems conforming to other standards. For the convenience of description, the term "eNB" used in the present disclosure can be used interchangeably with the term "gNB". That is, a base station described as an eNB can represent a gNB.

[0055] FIG. 1A is a diagram of a structure of a Long Term Evolution (LTE) system according to an embodiment of the present disclosure.

[0056] Referring toFIG. 1A The radio access network of the LTE system includes next-generation base stations (evolved Node Bs, hereinafter referred to as eNBs, Node Bs, or BSs) 1a-05, 1a-10, 1a-15, and 1a-20, a mobility management entity (MME) 1a-25, and a serving gateway (S-GW) 1a-30. A UE (or terminal) 1a-35 accesses an external network through the eNBs 1a-05 through 1a-20 and the S-GW 1a-30.

[0057] Reference FIG. 1A The eNBs 1a-05 through 1a-20 can correspond to existing Node Bs of a universal mobile telecommunications system (UMTS). The eNBs 1a-05 through 1a-20 can be connected to the UE 1a-35 through radio channels and can play a more complex role than the existing Node Bs. In the LTE system, all user traffic including real-time services such as voice over Internet protocol (VoIP) can be serviced through a shared channel. Therefore, a device that collects and schedules state information such as a buffer state of a UE, an available transmission power state, and a channel state can be required. This can be handled by the eNBs 1a-05 through 1a-20. One eNB can generally control multiple cells. For example, to achieve a transmission rate of 100 Mbps, the LTE system can use, for example, an orthogonal frequency division multiplexing (hereinafter referred to as OFDM) scheme as a radio access technology in a 20 MHz bandwidth. In addition, an adaptive modulation and coding (hereinafter referred to as AMC) scheme that determines a modulation scheme and a channel coding rate according to a channel state of a UE can be applied. The S-GW 1a-30 is an entity that provides a data bearer, and can add or release a data bearer according to control of the MME 1a-25. The MME 1a-25 is an entity that is responsible for various control functions as well as a mobility management function of a UE, and can be connected to multiple base stations.

[0058] FIG. 1B FIG. 1b is a diagram of a radio protocol architecture of an LTE system according to an embodiment of the disclosure.

[0059] Reference FIG. 1B The radio protocol of each of the UE and the eNB in the LTE system can include a packet data convergence protocol (PDCP) 1b-05 or 1b-40, a radio link control (RLC) 1b-10 or 1b-35, a medium access control (MAC) 1b-15 or 1b-30, and a physical entity (PHY) 1b-20 or 1b-25. The PDCP 1b-05 and 1b-40 can be responsible for operations such as IP header compression / decompression. The main functions of the PDCP are summarized as follows.

[0060] - Header compression and decompression function (Header compression and decompression: ROHC only).

[0061] - User data transfer function (User data transfer).

[0062] - In-sequence delivery function (Deliver upper layer PDUs in-sequence in PDCP re-establishment procedure for RLC AM).

[0063] - Reordering function (For split bearer in DC (RLC AM only): PDCP PDU routing for transmission and PDCP PDU reordering for reception).

[0064] - Duplicate detection function (Duplicate detection of lower SDU in PDCP re-establishment procedure for RLC AM)

[0065] - Reordering function (For split bearer in DC, retransmit PDCP SDU in handover, and for RLC AM, retransmit PDCP PDU in PDCP data recovery procedure).

[0066] - Encryption and deciphering function (Encryption and deciphering).

[0067] - Timer-based SDU discard function (Timer-based SDU discard in uplink).

[0068] RLC 1b-10 and 1b-35 can perform an automatic repeat request (ARQ) operation by reconfiguring PDCP protocol data units (PDUs) to an appropriate size. The main functions of the RLC are summarized as follows.

[0069] - Data transfer function (Transfer of upper layer PDUs).

[0070] - ARQ function (Error correction through ARQ (only for AM data transfer)).

[0071] - Concatenation, segmentation, and reassembly function (Concatenation, segmentation, and reassembly of RLC SDUs (only for UM and AM data transfer)).

[0072] - Re-segmentation function (Re-segmentation of RLC data PDUs (only for AM data transfer)).

[0073] - Reordering function (Reorder RLC data PDUs (only for UM and AM data transfer)).

[0074] - Duplicate detection function (Duplicate detection (only for UM and AM data transfer)).

[0075] - Error detection function (Protocol error detection (only for AM data transfer)).

[0076] - RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer)).

[0077] - RLC re-establishment function (RLC re-establishment).

[0078] The MAC 1b-15 and 1b-30 can be connected to a plurality of RLC entities configured in one UE, and can perform an operation of multiplexing and demultiplexing an RLC PDU into and from a MAC PDU. The main functions of the MAC are summarized as follows.

[0079] - Mapping function (mapping between logical channels and transport channels).

[0080] - Multiplexing and demultiplexing function (multiplexing MAC SDUs belonging to one or different logical channels into transport blocks (TBs) delivered to a physical entity on a transport channel / demultiplexing MAC SDUs belonging to one or different logical channels from transport blocks delivered to a physical entity on a transport channel)

[0081] - Scheduling information reporting function (scheduling information reporting).

[0082] - Hybrid automatic repeat request (HARQ) function (error correction through HARQ).

[0083] - Function of handling priorities among logical channels (priority handling among logical channels of one UE).

[0084] - Function of handling priorities among UEs (priority handling among UEs by means of dynamic scheduling).

[0085] - MBMS service identification function (MBMS service identification).

[0086] - Transport format selection function (transport format selection).

[0087] - Padding function (padding).

[0088] The PHY entity 1b-20 and 1b-25 can perform an operation of channel coding and modulation on upper layer entity data, make OFDM symbols of the upper layer entity data subjected to channel coding and modulation, and transmit the OFDM symbols on a radio channel, or demodulate OFDM symbols received through a radio channel, perform channel decoding on the demodulated OFDM symbols, and transmit the channel-decoded OFDM symbols to an upper layer entity.

[0089] FIG. 1C is a diagram of a structure of a next-generation mobile communication system according to an embodiment of the disclosure.

[0090] Referring to FIG. 1C , a radio access network of a next-generation mobile communication system (hereinafter, referred to as a new radio (NR) system or a 5G system) includes a next-generation base station (new radio Node B, hereinafter, referred to as an NR gNB or an NR BS) 1c-10 and a new radio core network (NR CN) 1c-05. A new radio user equipment (NR UE) (or terminal) 1c-15 can access an external network through the NR gNB 1c-10 and the NR CN 1c-05.

[0091] Referring to FIG. 1C , the NR gNB 1c-10 corresponds to an eNB of the existing LTE system. The NR gNB 1c-10 can be connected to the NR UE 1c-15 through a radio channel, and can provide services superior to those of the existing Node B. In the next-generation mobile communication system, all user traffic can be serviced through a shared channel. Therefore, an apparatus that collects and schedules state information such as a buffer state of the NR UE, an available transmission power state, and a channel state can be required. This can be handled by the NR gNB 1c-10. One NR gNB 1c-10 can generally control multiple cells. Compared to the existing LTE, the next-generation mobile communication system can have a bandwidth exceeding the existing maximum bandwidth in order to implement ultra-high-speed data transmission, and can additionally use a beamforming technique by using OFDM as a radio access technology. In addition, an AMC scheme of determining a modulation scheme and a channel coding rate according to a channel state of the NR UE can be applied. The NR CN 1c-05 can perform functions such as mobility support, bearer configuration, and quality of service (QoS) configuration. The NR CN 1c-05 is an entity responsible for various control functions as well as mobility management functions of the NR UE, and can be connected to multiple base stations. In addition, the next-generation mobile communication system can interoperate with the existing LTE system, and the NR CN 1c-05 can be connected to the MME 1c-25 through a network interface. The MME 1c-25 can be connected to the eNB 1c-30, that is, the existing base station.

[0092] FIG. 1D is a diagram of a radio protocol architecture of a next-generation mobile communication system according to an embodiment of the disclosure.

[0093] Referring to FIG. 1D , a wireless protocol of each of the UE and the NR gNB of the next-generation mobile communication system includes an NR SDAP 1d-01 or 1d-45, an NR PDCP entity 1d-05 or 1d-40, an NR RLC entity 1d-10 or 1d-35, an NR MAC 1d-15 or 1d-30, and a physical entity (PHY) 1d-20 or 1d-25.

[0094] The main functions of the NR SDAP 1d-01 or 1d-45 can include one or more of the following functions.

[0095] - User data transmission function (user plane data transmission).

[0096] - Function of mapping between QoS flow and data bearer of uplink (UL) and downlink (DL) (mapping between QoS flow and data radio bearer (DRB) of DL and UL).

[0097] - Function of marking QoS flow ID in UL and DL (marking QoS flow ID in DL and UL packets).

[0098] - Function of mapping a reflective QoS flow to a data bearer of a UL SDAP PDU (mapping of reflective QoS flow to DRB of UL SDAP PDU).

[0099] As for the SDAP entity, the UE can receive an RRC message to configure whether to use a header of the SDAP entity or whether to use a function of the SDAP entity for each PDCP entity, each bearer, or each logical channel. Further, when the SDAP header is configured, a 1-bit non-access stratum (NAS) reflective QoS indicator and a 1-bit access stratum (AS) reflective QoS indicator of the SDAP header can indicate the UE to update or reconfigure mapping information between QoS flow and data bearer of UL and DL. The SDAP header can include QoS flow ID information indicating QoS. The QoS information can be used as data processing priority, scheduling information, etc., in order to support efficient services.

[0100] The main functions of the NR PDCP entity 1d-05 and 1d-40 can include some of the following functions.

[0101] - Header compression and decompression function (header compression and decompression: only ROHC).

[0102] - User data transmission function (user data transmission).

[0103] - In-sequence delivery function (delivering upper layer entity PDUs in sequence).

[0104] - Out-of-sequence delivery function (delivering upper layer entity PDUs out of sequence).

[0105] - Reordering function (reordering of received PDCP PDUs).

[0106] - Duplicate detection function (duplicate detection of lower layer SDUs)

[0107] - Retransmission function (retransmission of PDCP SDU).

[0108] - Encryption and deciphering function (encryption and deciphering).

[0109] - Timer-based SDU discard function (timer-based SDU discard in uplink).

[0110] The reordering function of the NR PDCP entity 1d-05 and 1d-40 can refer to a function of sequentially reordering PDCP PDUs received from a lower layer based on a PDCP sequence number (SN). The reordering function of the NR PDCP entity 1d-05 and 1d-40 can include a function of transmitting data to an upper layer entity in a reordering order, a function of immediately transmitting data regardless of order, a function of reordering PDCP PDUs and recording missing PDCP PDUs, a function of reporting a status of missing PDCP PDUs to a transmitter, and a function of requesting retransmission of missing PDCP PDUs.

[0111] The main functions of the NR RLC entity 1d-10 and 1d-35 can include some of the following functions.

[0112] - Data transfer function (transfer of upper layer entity PDU).

[0113] - In-sequence delivery function (delivery of upper layer entity PDU in sequence).

[0114] - Out-of-sequence delivery function (delivery of upper layer entity PDU out of sequence).

[0115] - ARQ function (error correction through ARQ).

[0116] - Concatenation, segmentation, and reassembly function (concatenation, segmentation, and reassembly of RLC SDU).

[0117] - Re-segmentation function (re-segmentation of RLC data PDU).

[0118] - Reordering function (reordering of RLC data PDU).

[0119] - Duplicate detection function (duplicate detection).

[0120] - Error detection function (protocol error detection).

[0121] - RLC SDU discard function (RLC SDU discard).

[0122] - RLC re-establishment function (RLC re-establishment).

[0123] The in-sequence delivery function of the NR RLC entity 1d-10 and 1d-35 can refer to a function of sequentially transmitting the RLC SDU received from a lower layer to an upper layer entity. When an RLC SDU originally one is split into a plurality of RLC SDUs, and a plurality of RLC SDUs are received, the in-sequence delivery function of the NR RLC entity can include a function of reassembling the received RLC SDUs and transmitting the reassembled RLC SDUs, a function of reordering the received RLC PDUs based on the RLC SN or the PDCP SN, a function of reordering the RLC PDUs and recording missing RLC PDUs, a function of reporting the status of the missing RLC PDUs to the transmitter, and a function of requesting retransmission of the missing RLC PDUs. When there is a missing RLC SDU, the in-sequence delivery function of the NR RLC entity 1d-10 and 1d-35 can include sequentially transmitting only the RLC SDUs up to the missing RLC SDU to the upper layer entity. In addition, when there is a missing RLC SDU but a specific timer expires, the in-sequence delivery function of the NR RLC entity 1d-10 and 1d-35 can include sequentially transmitting all the RLC SDUs received before the timer starts to the upper layer entity, or when there is a missing RLC SDU and a specific timer expires, the in-sequence delivery function of the NR RLC entity 1d-10 and 1d-35 can include sequentially transmitting all the RLC SDUs received so far to the upper layer entity. In addition, the NR RLC entity 1d-10 and 1d-35 can process the RLC PDU in the order of reception (in the order of arrival, regardless of the order of the sequence number and the serial number), and transmit the processed RLC PDU to the PDCP entity regardless of the order (out-of-sequence delivery). When the received RLC PDU is segmented, the segments stored in the buffer or to be received in the future can be reconfigured into one complete RLC PDU, and processed and transmitted to the PDCP entity. The NR RLC entity 1d-10 and 1d-35 can not include a concatenation function, and the concatenation function can be performed by the NR MAC entity, or can be replaced with the multiplexing function of the NR MAC entity.

[0124] The out-of-sequence delivery function of the NR RLC entity 1d-10 and 1d-35 can refer to a function of directly transmitting the RLC SDU received from a lower layer to an upper layer entity regardless of the order, and when one RLC SDU is received after being split into a plurality of RLC SDUs, can include a function of reassembling and transmitting the split and received RLC SDUs, and a function of storing the RLC SN or the PDCP SN of the received RLC PDU, reordering the RLC PDU, and recording missing RLC PDUs.

[0125] The NR MAC 1d-15 and 1d-30 can be connected to a plurality of NR RLC entities configured in one UE, and the main functions of the NR MAC 1d-15 and 1d-30 can include some of the following functions.

[0126] - Mapping function (mapping between logical channels and transport channels).

[0127] - Multiplexing and demultiplexing function (multiplexing / demultiplexing MAC SDU)

[0128] *128 - Scheduling information reporting function (scheduling information reporting).

[0129] - HARQ function (error correction through HARQ).

[0130] - Function of handling priorities between logical channels (priority handling between logical channels of one UE).

[0131] - Function of handling priorities between UEs (priority handling between UEs by means of dynamic scheduling).

[0132] - MBMS service identification function (MBMS service identification).

[0133] - Transport format selection function (transport format selection).

[0134] - Padding function (padding).

[0135] The NR PHY layer 1d-20 and 1d-25 can channel-encode and modulate upper layer entity data, make OFDM symbols of the channel-encoded and modulated upper layer entity data, and transmit the OFDM symbols on a radio channel, or can demodulate OFDM symbols received through a radio channel, channel-decode the demodulated OFDM symbols, and transmit the channel-decoded OFDM symbols to an upper layer entity.

[0136] In the next-generation mobile communication system, a frequency of an ultra-high frequency band can be used, and thus a frequency bandwidth can also be significantly increased. However, in terms of implementation of a UE, this requires a very high implementation complexity, and a great cost to support all frequencies of the significantly increased bandwidth. Accordingly, in the next-generation mobile communication system, a concept of a bandwidth part (BWP) can be introduced, and a plurality of BWPs can be configured in one cell (a special cell (SP cell) or a secondary cell (SCell)), and data can be transmitted and received in one or more BWPs according to an indication of a base station.

[0137] The present disclosure provides a state transition method considering the state of an SCell and a plurality of BWPs configured in the SCell, or a BWP switching method when a dormant BWP is adopted and detailed operations thereof. In addition, the present disclosure provides a method of managing an idle mode and a transition state in a BWP level and a method of switching a BWP, and detailed operations for a BWP according to the state of each SCell, the state or mode (active, inactive, or idle) of each BWP.

[0138] In addition, according to an embodiment of the present disclosure, for each DL or each UL, a plurality of BWPs can be configured in one cell (SPCell, primary cell (PCell), primary SCell (PSCell), or SCell), and an active BWP (active DL or UL BWP), a dormant BWP (dormant DL BWP), or an inactive BWP (inactive or deactivated DL / UL BWP) can be configured and operated by switching the BWP. That is, for one cell, a DL BWP or a UL BWP can be transitioned to an active state, and thus, by using a method similar to a carrier aggregation technique, a data transmission rate can be increased. In addition, by transitioning or switching a DL BWP to a dormant BWP, a UE can not perform physical downlink control channel (PDCCH) monitoring on the above-described cell to reduce battery consumption, and the UE can perform channel measurement on the DL BWP and report a result of the channel measurement to subsequently support fast activation of a cell or a BWP. In addition, by transitioning a DL (or UL) BWP to an inactive state in a cell, battery consumption of a UE can be reduced. The state transition or switching of a BWP with respect to each BWP of each cell can be configured or indicated by using an RRC message, a MAC control element (CE), or downlink control information (DCI) of a PDCCH.

[0139] In the present disclosure, a BWP can be used without distinguishing between UL and DL, and each of a UL BWP and a DL BWP can be referred to based on a context.

[0140] In the present disclosure, a link can be used without distinguishing between UL and DL, and each of UL and DL can be referred to based on a context.

[0141] In the disclosure, a dormant BWP can be configured or employed for an SCell of a UE performing a carrier integration technique, and PDCCH can not be monitored in the dormant BWP to reduce battery consumption. In addition, in the dormant BWP, channel measurement can be performed and reported (for example, channel state information (CSI) or channel quality information (CQI) can be measured and reported), or beam measurement, beam tracking, or beam operation can be performed, and thus, when data transmission is required, the dormant BWP can be switched or activated as a normal BWP in order to quickly start data transmission in the normal BWP. For an SCell configured with PUCCH (which must continuously monitor signals, transmit or receive feedback, or identify and maintain synchronization), a dormant BWP can not be configured or applied.

[0142] In the disclosure, various embodiments are provided to operate based on PDCCH-based DCI, MAC CE, or RRC message to operate a dormant BWP for an SCell of a UE.

[0143] A network or base station can configure an SPCell (PCell and PSCell) and a plurality of SCells of a UE. When the UE communicates with one base station, the SPCell can refer to the PCell, and when the UE communicates with two base stations (a primary base station and a secondary base station), it can refer to the PCell of the primary base station or the PSCell of the secondary base station. The PCell or PSCell indicates a primary cell used by each MAC entity when the UE and the base station communicate with each other, and represents a cell that adjusts synchronization timing, performs random access, transmits HARQ ACK / NACK feedback based on a PUCCH transmission resource, and exchanges most control signals. The base station operates a plurality of SCells with the SPCell to increase transmission resources and increase UL or DL data transmission resources, and the technique is referred to as a carrier integration technique.

[0144] When the UE is configured with the SPCell and a plurality of SCells via an RRC message, the UE can be configured with a state or mode for a BWP of the SCell and each SCell via an RRC message, a MAC CE, or a DCI of a PDCCH. The state or mode of the SCell can be configured as an active mode, an activated state, a deactive mode, or a deactivated state. The SCell in the active mode or the activated state can indicate that the UE in the SCell in the active mode or the activated state can exchange UL data and DL data with the base station, can monitor a PDCCH to identify an indication of the base station, can perform a channel measurement for a DL of the SCell in the active mode or the activated state (or a BWP of the SCell other than an activated BWP, an activated normal BWP, or an activated dormant BWP), can periodically report measurement information to the base station, and can periodically transmit a pilot signal (a sounding reference signal (SRS)) to the base station so that the base station can perform an UL channel measurement, in the SCell in the deactive mode or the deactivated state.

[0145] However, the SCell in the deactive mode or the deactivated state can mean that the UE can not exchange data with the base station, can not monitor a PDCCH to identify an indication of the base station, can not perform a channel measurement, can not perform a measurement report, and can not transmit a pilot signal, because a BWP configured in the SCell is in a deactivated state, a configured BWP is not activated, or there is no activated BWP among the configured BWPs.

[0146] Accordingly, in order to activate the SCell in the deactive mode, first, the base station can configure the UE with frequency measurement configuration information by using an RRC message, and the UE can perform a cell or frequency measurement based on the frequency measurement configuration information. In addition, the base station can receive a report of the cell or frequency measurement from the UE, and then can activate the deactivated SCell based on the frequency / channel measurement information. Accordingly, when the base station activates the carrier aggregation technology for the UE and starts data transmission and reception, a great delay can occur.

[0147] In the disclosure, in order to reduce power consumption of the UE and promptly start data transmission or reception, an idle mode or a dormant state for a BWP of each activated SCell (or an active SCell) is provided, or a configuration or adoption of a dormant BWP for each activated SCell is provided.

[0148] In the BWP in the idle mode or the dormant BWP of the activated SCell, or when the dormant BWP is activated, the UE can not exchange data with the base station, can not monitor the PDCCH to identify the indication of the base station, or can not transmit the pilot signal, but the UE can perform the channel measurement and can report the measurement result for the frequency / cell / channel of the measurement periodically or when an event occurs according to the configuration of the base station. Therefore, since the UE does not monitor the PDCCH and transmit the pilot signal in the dormant BWP in the activated SCell, power consumption can be reduced compared to the normal BWP (or the BWP other than the dormant BWP) in the activated SCell, or when the normal BWP (or the BWP other than the dormant BWP) in the activated SCell is activated. In addition, unlike when the SCell is deactivated, the UE can report the channel measurement, and thus, the base station can quickly activate the normal BWP in the activated SCell based on the measurement report or the measurement report of the dormant BWP in the activated SCell to quickly use the carrier aggregation technology, and thus, the transmission delay can be reduced.

[0149] Therefore, in the disclosure, the SCell in the active mode or the activated state can mean that, in the SCell in the active mode or the activated SCell, the UE in the BWP of the SCell (other than the activated BWP, the activated normal BWP, or the activated dormant BWP) can exchange UL data and DL data with the base station, can monitor the PDCCH to identify the indication of the base station, can perform the channel measurement for the DL of the SCell in the active mode or the activated state (or the BWP of the SCell other than the activated BWP, the activated normal BWP, or the activated dormant BWP), can report the measurement information to the base station periodically, and can transmit the pilot SRS to the base station periodically so that the base station can perform the UL channel measurement. In addition, in the disclosure, the SCell in the active mode or the activated state can mean that the UE in the activated dormant BWP in the SCell in the active mode or the activated state can not exchange UL data or DL data with the base station, and can not monitor the PDCCH to identify the indication of the base station, but the UE can perform the channel measurement for the DL of the activated dormant BWP in the SCell in the active mode or the activated state, and can report the measurement information to the base station periodically.

[0150] In addition, in the disclosure, the dormant BWP can indicate the state of the BWP, or the dormant BWP can be used as a term indicating the logical concept of indicating a specific BWP. Therefore, the dormant BWP can be activated, deactivated, or switched. For example, an indication to switch the second activated BWP in the first SCell to the dormant BWP, an indication to not activate the first SCell or to convert the first SCell to the idle mode, or an indication to activate the dormant BWP in the first SCell can be interpreted as having the same meaning.

[0151] Further, in the disclosure, the normal BWP can indicate a BWP other than the dormant BWP among BWPs configured in each SCell of the UE via an RRC message. In the normal BWP, the UE can exchange UL data or DL data with the base station, can monitor a PDCCH to identify an indication from the base station, can perform channel measurement on a DL, can periodically report measurement information to the base station, and can periodically transmit a pilot SRS to the base station so that the base station can perform UL channel measurement. Further, the normal BWP can mean a first active BWP, a default BWP, a first active BWP from a dormant state, or an initial BWP.

[0152] Further, among the BWPs configured in each SCell of the UE, the dormant BWP can be configured only for a DL. According to another method, among the BWPs configured in each SCell of the UE, one dormant BWP can be configured for a UL or a DL.

[0153] FIG. 1E FIG. 1 is a diagram of a procedure of providing a service to a terminal by efficiently using a large frequency bandwidth in a next-generation mobile communication system according to an embodiment of the disclosure.

[0154] Reference FIG. 1E describes how a next-generation mobile communication system efficiently uses a large frequency bandwidth to provide a service to UEs having different capabilities or categories and allows the UEs to reduce power consumption.

[0155] One cell to which the base station provides a service can receive a significantly large frequency band 1e-05 of a service. However, in order to provide a service to UEs having different capabilities, the large frequency band can be divided into a plurality of BWPs and managed as one cell.

[0156] First, the UE that is turned on in advance can search for the entire frequency band provided by the operator (PLMN) in units of predetermined resource blocks (e.g., in units of 12 resource blocks (RB)). That is, the UE can start searching for a primary synchronization sequence (PSS) / secondary synchronization sequence (SSS) in the entire system bandwidth in units of RB 1e-10. When the UE searches for the PSS / SSS 1e-01 or 1e-02 in units of RB and detects a signal, the UE can read and interpret (decode) the signal to identify the boundary between a subframe and a radio transmission resource frame. Accordingly, the subframe can be identified in units of 1 ms, and the base station can be synchronized with the DL signal. The RB can be defined as a two-dimensional unit based on the size of the predetermined frequency resource and the predetermined time resource. For example, based on the time resource, the RB can be defined as a unit of 1 ms, and based on the frequency resource, the RB can be defined as a unit of 12 subcarriers (1 carrier x 15 kHz = 180 kHz). After completing synchronization, the UE can identify a master system information block (MIB) or minimum system information (MSI) to identify information of a control resource set (CORESEST) and identify initial access BWP information (1e-15 and 1e-20). The CORESET information refers to the location of the time / frequency transmission resource through which a control signal is transmitted from the base station, and for example, indicates the location of the transmission resource through which the PDCCH is transmitted. That is, the CORESET information can be information indicating from where the first system information (system information block 1 (SIB1)) is transmitted, and the CORESET information can indicate via which frequency / time resource the PDCCH is transmitted. When the UE reads the first system information, the UE can identify information about the initial BWP. As described above, the UE can complete synchronization of the DL signal with the base station, and when the UE can receive a control signal, in the initial BWP of the cell in which the UE camps, the UE can perform a random access procedure, request an RRC connection configuration, receive an RRC message, and perform the RRC connection configuration.

[0157] In the RRC connection configuration, a plurality of BWPs can be configured for each cell (PCell, PSCell, SPCell, or SCell). In one cell, a plurality of BWPs can be configured for DL, and in addition, a plurality of BWPs can be configured for UL.

[0158] The plurality of BWPs can be indicated or configured via a BWP identifier (identifier) so as to be used as an initial BWP, a default BWP, a first active BWP, a dormant BWP, or a first active BWP from a dormant state.

[0159] The initial BWP can be used as a cell-specific BWP defined to exist in each cell, and can be used as a BWP used when a UE initially accessing a cell configures a connection with the cell through a random access procedure or performs synchronization after configuring a connection. Further, for each cell, a base station can configure each of an initial downlink BWP to be used in the DL and an initial uplink BWP to be used in the UL. Further, configuration information about the initial BWP can be broadcast via first system information (system information 1, SIB1) indicated by a CORESET, and the base station can reconfigure the initial UL BWP to a UE accessing a connection by using an RRC message. Further, the initial BWP can be used by assigning a number 0 to a BWP identifier in each of the UL and the DL. That is, all UEs accessing the same cell can use the initial BWP by equally assigning the initial BWP through a BWP identifier with a number 0 or the like. This is because, when in performing a random access procedure, the base station can transmit a random access response (RAR) message through the initial BWP that can be read by all UEs, a contention-based random access procedure can become simple.

[0160] The first active BWP can be configured differently for each UE (UE-specific), and can be indicated from among a plurality of BWPs by designation with a BWP identifier. The first active BWP can be configured for each of the DL and the UL, and each of the first active DL BWP and the first active UL BWP can be configured via a BWP identifier. When a plurality of BWPs are configured in one cell, the first active BWP can be used to indicate which BWP will be activated and used first. For example, when a PCell or a PSCell and a plurality of SCells are configured for a UE, and a plurality of BWPs are configured in the PCell or the PSCell or the SCell, when the PCell or the PSCell or the SCell is activated, the UE can activate and use the first active BWP from among the plurality of BWPs configured in the PCell or the PSCell or the SCell. That is, the UE can activate and use the first active DL BWP for the DL, and activate and use the first active UL BWP for the UL.

[0161] When the UE receives an indication to activate a SCell or a BWP in a deactivated state via an RRC message, MAC control information, or DCI, the following operations can be performed, in which the UE switches a current DL BWP or an active DL BWP in the SCell to activate the current DL BWP or the active DL BWP in the SCell as a first active DL BWP (or a BWP configured or indicated via an RRC message), or switches a current UL BWP or an active UL BWP in the SCell to activate the current UL BWP or the active UL BWP in the SCell as a first active UL BWP (or a BWP configured or indicated via an RRC message). In addition, when the UE receives an indication to transition a SCell or a BWP to a dormant state via an RRC message, MAC control information, or DCI, the operation can be performed. This is because, when the current DL BWP or the active DL BWP in the activated SCell is switched to be activated as the first active DL BWP (or a BWP configured or indicated by using an RRC message) or the UL BWP is switched to be activated as the first active UL BWP (or a BWP configured or indicated by using an RRC message), even when channel measurement and reporting are performed in the dormant state, frequency / channel measurement must be performed and reported with respect to the first active DL / UL BWP in order for the base station to efficiently use a carrier aggregation technique.

[0162] The default BWP can be configured differently for each UE (UE-specific), and can be indicated from among a plurality of BWPs by designation via a BWP identifier. The default BWP can be configured only for DL. The default BWP can be used as a BWP to which an active BWP among a plurality of downlink BWPs will fall back after a predetermined time. For example, a BWP deactivation timer (BWP inactivity timer) can be configured for each cell or each BWP by using an RRC message, and the BWP deactivation timer can be started or restarted when data transmission and reception occur in an active BWP other than the default BWP, or can be started or restarted when the active BWP is switched to another BWP. When the BWP deactivation timer expires, the UE can fall back or switch the active DL BWP in the cell to the default BWP. The switching can mean a process of deactivating a current active BWP and activating a BWP indicated to be switched, and the switching can be triggered via an RRC message, MAC control information (MAC CE), or L1 signaling (DCI of a PDCCH). The switching can be triggered by indicating a BWP to be switched to or activated, and the BWP can be indicated by a BWP identifier (e.g., 0, 1, 2, 3, or 4).

[0163] The reason for using the default BWP by applying only to the DL is that for each cell, the base station can allow the UE to fall back to the default BWP after a certain period of time to receive the indication of the base station (e.g., DCI of PDCCH), and thus, the scheduling of the base station can become simple. For example, when the base station configures the default BWP of the UE accessing one cell as the initial BWP, after a certain period of time, the base station can perform scheduling indication only for the initial BWP. When the default BWP is not configured in the RRC message, the initial BWP can be regarded as the default BWP, and when the BWP deactivation timer expires, the BWP can fall back to the initial BWP.

[0164] According to another method, in order to increase the degree of freedom of the embodiment of the base station, the default BWP can also be defined and configured for the UL, and can be used in the same method as the default BWP of the DL.

[0165] The dormant BWP means a BWP in an idle mode or a dormant BWP of an activated SCell, or when the dormant BWP is activated, according to the configuration of the base station, the UE can not exchange data with the base station, can not monitor the PDCCH to identify the indication of the base station, or can not transmit the pilot signal, but can perform channel measurement, and can periodically or upon an event, report the measurement result for the measured frequency / cell / channel. Thus, because the UE does not monitor the PDCCH and transmit the pilot signal in the dormant BWP in the activated SCell, power consumption can be reduced compared to the normal BWP (or the BWP other than the dormant BWP) in the activated SCell, or compared to when the normal BWP (or the BWP other than the dormant BWP) in the activated SCell is activated. In addition, unlike when the SCell is deactivated, the UE can report the channel measurement, and thus, the base station can quickly activate the normal BWP in the activated SCell based on the measurement report or the measurement report of the dormant BWP in the activated SCell to quickly use the carrier aggregation technology, and thus, transmission delay can be reduced.

[0166] The first active BWP switched and activated from the dormant state or the dormant BWP (or the first active non-dormant BWP or the BWP configured or indicated by using the RRC message) can be a BWP that the UE must activate by switching the current or active BWP in the SCell according to the following indication, or a BWP that the UE must activate from the dormant state configured via the RRC message, wherein the indication includes: an indication from the base station to the UE via DCI of PDCCH, MAC CE, or RRC message to switch the BWP in the activated SCell from the dormant BWP to the normal BWP (or the BWP other than the dormant BWP) when the UE operates the BWP in the activated SCell as the dormant BWP, the active BWP in the activated SCell is the dormant BWP, or the BWP in the SCell is converted to the dormant BWP; an indication to switch or convert the active BWP in the dormant BWP to the normal BWP; or an indication to switch, convert, or activate the active BWP in the dormant BWP to the normal BWP (e.g., the first active BWP activated from the dormant state).

[0167] FIG. 1F A diagram illustrating a procedure in which a UE transitions from an RRC idle mode to an RRC connected mode in a next-generation mobile communication system according to an embodiment of the disclosure, and a method of configuring a plurality of BWPs and configuring a default BWP or a first active BWP is shown.

[0168] One cell to which a base station provides service can receive service of a significantly large frequency band. First, the UE can search for the entire frequency band provided by an operator (PLMN) in units of predetermined resource blocks (e.g., in units of 12 RBs). That is, the UE can start searching for PSS / SSS in the entire system bandwidth in units of RBs. When the UE searches for PSS / SSS in units of RBs and detects a signal, the UE can read and interpret (decode) the signal to identify the boundary between subframes and radio transmission resource frames. When the UE completes synchronization, the UE can read the system information of the cell currently residing. That is, the UE can identify MIB or MSI to identify information of a CORESET and read system information to identify information about an initial BWP (1f-01 and 1f-05). The CORESET information refers to the location of a time / frequency transmission resource through which a control signal is transmitted from the base station, and for example, indicates the location of a transmission resource through which a PDCCH is transmitted.

[0169] As described above, when the UE completes DL synchronization with the base station and can receive a control signal, the UE can perform a random access procedure in the initial BWP, request an RRC connection configuration, receive an RRC message, and perform an RRC connection configuration (1f-10, 1f-15, 1f-20, 1f-25, and 1f-30).

[0170] After the default RRC connection configuration is completed, the base station can transmit an RRC message to the UE to inquire about the UE capability to identify the UE capability (UECapabilityEnquiry, 1f-35). According to another method, the base station can inquire about the UE capability to the MME or AMF to identify the UE capability. This is because the MME or AMF can store information about the UE capability when the UE is previously connected. When the information about the UE capability required by the base station does not exist, the base station can request the information about the UE capability to the UE.

[0171] The base station can transmit an RRC message to the UE to identify the capability of the UE, thereby identifying the performance of the UE, for example, identifying the frequency band range readable by the UE or identifying the frequency band domain readable by the UE. Furthermore, after the base station identifies the performance of the UE, the base station can configure an appropriate BWP for the UE. When the UE receives the RRC message inquiring about the UE capability, the UE can indicate the range of the bandwidth supported by the UE or the range of the bandwidth supported by the current system bandwidth via an offset from a reference center frequency, via a direct indication of the start and end points of the supported frequency bandwidth, or via a center frequency and a bandwidth (1f-40) in response to the RRC message.

[0172] The BWP can be configured via an RRCSetup message or an RRCResume message or an RRCReconfiguration message (1f-45) of the RRC connection configuration, the RRC message can include configuration information about a PCell, a PSCell, or a plurality of SCells, and a plurality of BWPs can be configured for each cell (PCell, PSCell, or SCell). When a plurality of BWPs are configured for each cell, a plurality of BWPs available for DL of each cell can be configured, and in the case of an FDD system, a plurality of BWPs available for UL of each cell can be additionally configured separately from the DL BWP. In the case of a TDD system, a plurality of BWPs available commonly to DL and UL of each cell can be configured.

[0173] The information for configuring the BWP of each cell (PCell, PSCell, or SCell) can include some of the following information.

[0174] - DL BWP configuration information of the cell.

[0175] - Initial DL BWP configuration information.

[0176] - Information about the configuration of a plurality of BWPs and a BWP identifier (ID) corresponding to each BWP.

[0177] - Information about initial state configuration of the DL BWP of the cell (for example, an active state, a dormant state, or a deactivation state).

[0178] - BWP ID indicating the first active DL BWP.

[0179] - BWP ID indicating the default BWP.

[0180] - Configuration information for PDCCH monitoring for each BWP. For example, CORESET information, search space resource information, or information on PDCCH transmission resources, periodicity, or subframe number.

[0181] - For each BWP in the BWP configuration information, BWP ID indicating the dormant BWP, or a 1-bit indicator indicating the dormant BWP.

[0182] - For each BWP in the BWP configuration information, BWP ID indicating the first active BWP activated from the dormant state, or a 1-bit indicator indicating the first active BWP activated from the dormant state.

[0183] - BWP deactivation timer configuration and timer value.

[0184] - UL BWP configuration information of the cell.

[0185] - Initial UL BWP configuration information.

[0186] - Configuration information of a plurality of BWPs and BWP ID corresponding to each BWP.

[0187] - Initial state configuration information (e.g., active state, dormant state, or deactivated state) of the DL BWP of the cell.

[0188] - For each BWP in the BWP configuration information, BWP ID indicating the dormant BWP, or a 1-bit indicator indicating the dormant BWP.

[0189] - BWP ID indicating the first active UL BWP.

[0190] The configured initial BWP, default BWP, or first active BWP can be used for the following purposes, and can be operated according to the purposes described below.

[0191] The initial BWP can be used as a cell-specific BWP defined to exist in each cell, and can be used as a BWP used when a UE initially accessing a cell configures a connection with the cell through a random access procedure or performs synchronization after configuring the connection. Further, for each cell, a base station can configure each of an initial downlink BWP to be used in the DL and an initial uplink BWP to be used in the UL. Further, configuration information about the initial BWP can be broadcast via first system information (system information 1, SIB1) indicated by a CORESET, and the base station can reconfigure the initial UL BWP to a UE accessing a connection by using an RRC message. Further, the initial BWP can be used by assigning a number 0 to a BWP identifier in each of the UL and the DL. That is, all UEs accessing the same cell can use the initial BWP by equally assigning the initial BWP through the BWP identifier with the number 0 or the like. This is because, when in performing a random access procedure, the base station can transmit a random access response (RAR) message through the initial BWP that can be read by all UEs, a contention-based random access procedure can become simple.

[0192] The first active BWP can be configured differently for each UE (UE-specific), and can be indicated from among a plurality of BWPs by designation with a BWP identifier. The first active BWP can be configured for each of the DL and the UL, and each of the first active DL BWP and the first active UL BWP can be configured via a BWP identifier. When a plurality of BWPs are configured in one cell, the first active BWP can be used to indicate which BWP will be activated and used first. For example, when a PCell or a PSCell and a plurality of SCells are configured for a UE, and a plurality of BWPs are configured in the PCell or the PSCell or the SCell, when the PCell or the PSCell or the SCell is activated, the UE can activate and use the first active BWP from among the plurality of BWPs configured in the PCell or the PSCell or the SCell. That is, the UE can activate and use the first active DL BWP for the DL, and activate and use the first active UL BWP for the UL.

[0193] When the UE receives an indication to activate a specific SCell or a BWP in a specific activated SCell in a deactivated state or a dormant state via an RRC message, a MAC CE, or a DCI of a PDCCH, or an indication to switch or activate a deactivated or dormant BWP to a normal BWP, the UE can perform the following operations in which the UE switches a current DL BWP or an activated DL BWP in the SCell to activate the current DL BWP or the activated DL BWP in the SCell to a first active DL BWP (or a BWP configured or indicated via an RRC message), or switches a current UL BWP or an activated UL BWP in the SCell to activate the current UL BWP or the activated UL BWP in the SCell to a first active UL BWP (or a BWP configured or indicated via an RRC message). In addition, when the UE receives an indication to transition an activated SCell or a BWP to a dormant state or to switch an activated SCell or a BWP to a dormant BWP via an RRC message, a MAC CE, or a DCI of a PDCCH, the UE can switch or activate the BWP to the dormant BWP, or can not activate the BWP.

[0194] The deactivation, switching to the dormant BWP, or activation of the dormant BWP can mean that the operation provided in the dormant state according to the disclosure is performed. That is, the UE can not perform monitoring of the PDCCH, and can perform channel measurement on the DL BWP (or the dormant BWP), and can report the measurement result to the base station. According to another method, when the SCell is activated or the BWP is activated or switched to the normal BWP, the initial active DL BWP can be activated by switching the DL BWP, and the initial active UL BWP can be activated by switching the UL BWP, and thus, the dormant BWP can be configured as the initial active DL BWP, the initial active UL BWP, or the default BWP. The default BWP can be configured differently for each UE (UE-specific), and can be indicated from among a plurality of BWPs by designation via a BWP ID. The default BWP can be configured only for DL. The default BWP can be used as a BWP to which an activated BWP among a plurality of downlink BWPs will be backed off after a predetermined time. For example, a BWP deactivation timer (BWP inactivity timer) can be configured for each cell or each BWP by using an RRC message, and can be started or restarted when data transmission and reception occur in an activated BWP other than the default BWP, or can be started or restarted when the activated BWP is switched to another BWP. When the BWP deactivation timer expires, the UE can back off or switch the active DL BWP in the cell to the default BWP. The switching can mean a process of deactivating the current active BWP and activating the BWP indicated to be switched, and the switching can be triggered via an RRC message, a MAC control information (MAC CE), or L1 signaling (DCI of the PDCCH). The switching can be triggered by indicating the BWP to be switched to or activated, and the BWP can be indicated by a BWP identifier (for example, 0, 1, 2, 3, or 4).

[0195] The reason for using the default BWP by applying only to the DL is that, for each cell, the base station can allow the UE to back off to the default BWP after a certain period of time to receive an indication of the base station (for example, DCI of the PDCCH), and thus, the scheduling of the base station can become simple. For example, when the base station configures the default BWP of the UE accessing one cell as the initial BWP, after a certain period of time, the base station can perform scheduling indication only for the initial BWP. When the default BWP is not configured in the RRC message, the initial BWP can be regarded as the default BWP, and when the BWP deactivation timer expires, the BWP can back off to the initial BWP.

[0196] According to another method, in order to increase the degree of freedom of the embodiment of the base station, the default BWP can also be defined and configured for the UL, and can be used in the same method as the default BWP of the DL.

[0197] The dormant BWP means a BWP in an idle mode or a dormant BWP of an activated SCell, or when the dormant BWP is activated, according to a configuration of a base station, the UE can not exchange data with the base station, can not monitor a PDCCH to identify an indication of the base station, or can not transmit a pilot signal, but can perform channel measurement, and can report a measurement result for a measured frequency / cell / channel periodically or when an event occurs. Therefore, since the UE does not monitor the PDCCH and transmit the pilot signal in the dormant BWP in the activated SCell, power consumption can be reduced compared to a normal BWP (or a BWP other than the dormant BWP) in the activated SCell, or compared to when the normal BWP (or the BWP other than the dormant BWP) in the activated SCell is activated. In addition, unlike when the SCell is deactivated, the UE can report the channel measurement, and thus, the base station can quickly activate the normal BWP in the activated SCell based on the measurement report or the measurement report of the dormant BWP in the activated SCell to quickly use a carrier aggregation technique, and thus, transmission delay can be reduced.

[0198] The first active BWP activated from the dormant state (or the first active non-dormant BWP) can be a BWP that the UE must activate by switching a current or active BWP in the activated SCell according to an indication including: an indication from the base station to the UE via a DCI of a PDCCH, a MAC CE, or an RRC message to switch a BWP in the activated SCell from the dormant BWP to the normal BWP (or a BWP other than the dormant BWP) when the UE operates a BWP in one activated SCell as the dormant BWP, an active BWP in the activated SCell is the dormant BWP, or a BWP in the SCell is converted to the dormant BWP; an indication to switch or convert an active BWP in the dormant BWP to the normal BWP; or an indication to switch, convert, or activate an active BWP in the dormant BWP to the normal BWP (for example, the first active BWP activated from the dormant state).

[0199] In the disclosure, switching the first BWP to the second BWP can mean activating the second BWP or deactivating the activated first BWP and activating the second BWP.

[0200] Further, in the RRCSetup message or the RRCResume message 1f-25 or the RRCReconfiguration message 1f-45 in the RRC connection configuration, a state transition timer can be configured so that the UE can directly perform state transition even when the UE does not receive an indication from the base station via an RRC message, a MAC control information, or a DCI of a PDCCH. For example, a cell deactivation timer (ScellDeactivationTimer) is configured for each SCell, and when the cell deactivation timer expires, the SCell can transition to the deactivated state. Alternatively, a DL (or UL) BWP hibernation timer (DLBWPHibernationTimer or ULBWPHibernationTimer) can be configured for each SCell or each BWP of the SCell, and a SCell hibernation timer (SCellHibernationTimer) can be configured for each SCell, so that when the SCell hibernation timer or the DL (or UL) BWP hibernation timer expires, the SCell or the DL (or UL) BWP can transition to the hibernation state or switch to the hibernation BWP. For example, when the cell hibernation timer or the DL (or UL) BWP hibernation timer expires, the SCell or the DL (or UL) BWP in the active state can transition to the hibernation state or switch to the hibernation BWP, and the SCell or the DL (or UL) BWP in the hibernation state can not transition to the hibernation state or the hibernation BWP. Further, the BWP hibernation timer can be started when an indication to switch the BWP or an indication to activate the BWP is received through an RRC message, a MAC CE, or a DCI of a PDCCH, or the BWP hibernation timer can be stopped when an indication to switch the BWP to the hibernation BWP, an indication to not activate the BWP, or an indication to activate the hibernation BWP is received through an RRC message, a MAC CE, or a DCI of a PDCCH. Further, a dormant SCell deactivation timer or a dormant state or DL (or UL) hibernation BWP deactivation timer (dormantDLDeactivationTimer or dormantULDeactivationTimer) can be configured for each SCell or the DL (or UL) BWP, so that the SCell or the DL (or UL) hibernation BWP in the dormant state can transition to the deactivated state. When the dormant SCell deactivation timer or the dormant state or DL (or UL) hibernation BWP deactivation timer expires, only the SCell or the DL (or UL) hibernation BWP in the dormant state can transition to the deactivated state, and the SCell or the DL (or UL) BWP in the active state or the deactivated state can not transition to the deactivated state.In addition, the hibernation BWP sleep timer can be started when an indication to switch the hibernation BWP, an indication to not activate the hibernation BWP, or an indication to activate the hibernation BWP is received through an RRC message, a MAC CE, or a DCI of a PDCCH, or can be stopped when an indication to not activate or activate a BWP or a SCell or an indication to activate a normal BWP (e.g., a BWP configured via RRC except for the hibernation BWP) is received through an RRC message, a MAC CE, or a DCI of a PDCCH. When the SCell deactivation timer (or the DL (or UL) BWP sleep timer) and the cell hibernation timer (or the DL (or UL) hibernation BWP deactivation timer) are configured together, the SCell hibernation timer (or the DL (or UL) hibernation BWP sleep timer) can be processed preferentially. That is, when the SCell hibernation timer (or the DL (or UL) BWP sleep timer) is configured, the SCell or the DL (or UL) BWP can not be deactivated even though the SCell deactivation timer (or the DL (or UL) hibernation BWP deactivation timer) expires. In other words, when the cell hibernation timer (or the DL (or UL) BWP sleep timer) is configured, the SCell or the DL (or UL) BWP can be initially converted from an active state to a hibernation state or switched to a hibernation BWP via expiration of the timer, and the SCell or the BWP converted to the hibernation state can be gradually converted back to a deactivated state via expiration of the hibernation state SCell or BWP deactivation timer. Accordingly, when the SCell hibernation timer or the BWP sleep timer is configured, the SCell deactivation timer or the hibernation BWP deactivation timer does not affect the state conversion of the SCell or the DL (or UL) BWP, and when the SCell hibernation timer or the BWP sleep timer is configured, the SCell or the DL (or UL) BWP can not be directly converted to the deactivated state even when the SCell deactivation timer or the hibernation BWP deactivation timer expires.

[0201] When the SCell deactivation timer (or the DL (or UL) BWP sleep timer) is not configured in the RRC message, the UE can consider that the SCell deactivation timer (or the DL (or UL) BWP sleep timer) is configured as an infinite value.

[0202] Further, the RRCSetup message or the RRCResume message 1f-25 or the RRCReconfiguration message 1f-45 of the RRC connection configuration can configure frequency measurement configuration information, frequency measurement gap configuration information, and the like, and can include frequency measurement object information. Further, the RRCSetup message or the RRCResume message 1f-25 or the RRCReconfiguration message 1f-45 of the RRC connection configuration can configure a power saving mode for reducing power consumption of the UE, and together with the function of reducing power consumption, can configure a discontinuous reception (DRX) cycle, an offset, or an on-duration portion (a portion in which the UE is to monitor a PDCCH), configuration information such as time information, time information about a time point at which the UE is to monitor the PDCCH from the base station before the on-duration portion during the DRX cycle, short time cycle information, and the like. When the function for reducing power consumption of the UE is configured, the UE can configure the DRX cycle, and can detect a wake-up signal (WUS) in a portion in which the UE is configured to monitor the PDCCH of the base station before the on-duration portion, and the base station can indicate to the UE whether to skip (or not to perform) or to perform monitoring of the PDCCH in the next on-duration portion through DCI of the PDCCH of the WUS. The UE always has to monitor the PDCCH in the on-duration portion. However, via the WUS described above, the base station can indicate to the UE not to perform monitoring of the PDCCH in the on-duration portion, and thus, battery consumption of the UE can be reduced.

[0203] When the RRC connection configuration is completed as described above, the UE can configure a plurality of BWPs according to an indication configured by using an RRC message. In addition, the UE can activate one or a few of the configured plurality of BWPs to reduce power consumption. For example, one BWP can be indicated to be activated. In addition, the base station can indicate to activate a BWP by using an RRC message, a MAC CE, or L1 signaling (a PHY layer control signal such as DCI of a PDCCH) to indicate that an initial access BWP is switched to a new BWP. According to another method, new bitmap information can be defined in DCI of a PDCCH, and whether to activate, not to activate, or to deactivate can be indicated. According to another method, whether to activate a normal BWP (for example, a first active BWP to be activated from sleep), whether to activate a dormant BWP, or whether to switch a BWP to a dormant BWP, or whether to switch a BWP can be indicated by using a bitmap. In an initial access BWP, there can be many newly accessed users, and thus, in terms of scheduling, it can be more advantageous to allocate a new BWP and manage connected users separately. This is because the initial access BWP is not configured for each UE and can be commonly shared by all UEs. In addition, in order to reduce signaling overhead, a default BWP can be dynamically indicated by using a MAC CE, L1 signaling, or system information.

[0204] In the disclosure, when a base station or a network supports MBS for a UE, the base station or the network can configure bearer configuration information of the MBS or transmission resource information (for example, time resource, frequency resource, bandwidth, frequency, BWP (or BWP ID), bandwidth, subcarrier spacing, transmission resource period, radio network temporary identifier (RNTI) for each MBS, or logical channel ID for each MBS) of the MBS for the UE by using system information, an RRC message (for example, RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel. According to another method, the bearer configuration information of the MBS can be agreed or specified with a default configuration. From the perspective of the base station or the UE, the bearer of the MBS can be regarded as a multicast bearer or a unicast bearer. According to another method, the base station or the network can configure the bearer of the UE by configuring an additional ID or an indicator by using system information, an RRC message (for example, RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel, thereby configuring the bearer of the UE by distinguishing between the multicast bearer of the MBS and the unicast bearer of the MBS.

[0205] The DL shared channel (DL-SCH) described in the disclosure can include or indicate a common control channel (CCCH), a dedicated control channel (DCCH), or a dedicated traffic channel (DTCH).

[0206] The bearer of the MBS, the multicast bearer, or the unicast bearer described in the disclosure can be interpreted as the multicast bearer or the unicast bearer.

[0207] In the disclosure, the bearer can represent a concept including a signaling radio bearer (SRB) and a data radio bearer (DRB). The SRB can be mainly used to transmit and receive an RRC message of an RRC entity, and the DRB can be mainly used to transmit and receive user layer data. In addition, the UM DRB can represent a DRB using an RLC entity operating in a non-acknowledgment mode (UM), and the AMDRB can represent a DRB using an RLC entity operating in an acknowledgment mode (AM).

[0208] The MBS data described in the disclosure can be interpreted as MBS control data (control plane data) of configuration information of an MBS channel, bearer configuration, or service configuration, or MBS user data (user plane data) supporting the MBS.

[0209] The RNTI described in the disclosure is an identifier used when the UE monitors a PDCCH via a PHY layer, descrambles or checks a cyclic redundancy check (CRC) of the received PDCCH, identifies whether the CRC of the PDCCH corresponds to an RNTI value configured for the UE or an RNTI value corresponding to a PDCCH to be received by the UE, and determines whether the CRC of the PDCCH is the PDCCH to be read by the UE.

[0210] FIG. 1G is a diagram of a structure of a bearer established when a base station or a network supports MBS of a UE in an RRC connected mode, an RRC inactive mode, or an RRC idle mode by configuring the MBS using system information, an RRC message, or a control message for an MBS channel, or a structure of a bearer established for the UE to receive the MBS according to an embodiment of the disclosure. In addition, FIG. 1G The bearer structure provided in the disclosure can also be applied or configured by extension to support a general data service.

[0211] FIG. 1G is a diagram describing a bearer structure for supporting an MBS configured by a base station or a network using system information, an RRC message, or a control message for an MBS channel when the base station or the network supports MBS of a UE in an RRC connected mode, an RRC inactive mode, or an RRC idle mode or the UE receives the MBS according to an embodiment of the disclosure.

[0212] Reference FIG. 1G, the bearer structure configured for the MBS can have one or more of the following bearer structures. For the bearer configuration information of the MBS, one or more of the following bearer structures can be agreed or specified with a default configuration. In addition, the following bearer structures can be configured in the UE or the base station, or applied to the UE or the base station.

[0213] First bearer structure 1g-01: When a unicast bearer or a multicast bearer for the MBS is configured as FIG. 1GWhen the first bearer structure 1g-01 is illustrated, the UE can configure a bearer structure directly connecting a MAC entity and an upper layer MBS application layer as a bearer of MBS. In the first bearer structure, a procedure of transmitting HARQ ACK or NACK, retransmitting HARQ, or processing HARQ of the MAC entity can not be applied to the first bearer structure. Alternatively, in the first bearer structure, the UE can transmit MBS data (MBS control data or MBS user data) received through the PHY layer or the MAC entity to the upper layer MBS application layer. In the first bearer structure, the MBS data can not include a MAC header. For example, this is because, when an additional physical channel or a transport channel of MBS is configured, and an additional transmission resource (a frequency, a time resource, or a transmission period) is configured, the MBS data can be identified by the MAC entity without a MAC header. According to another method, for example, this is because, when an additional physical channel or a transport channel of MBS is configured, and an additional transmission resource (a frequency, a time resource, or a transmission period) is configured, and when a first RNTI of MBS data is allocated or defined, the PHY layer or the MAC entity can identify the MBS data without a MAC header. The RNTI of the MBS data can be allocated or designated with each of a 1-1th RNTI for MBS control data (or an MBS control data channel) and a 1-2th RNTI for MBS user data (or an MBS user data channel). In the first bearer structure, the MAC entity can not apply a procedure of transmitting HARQ ACK or NACK, retransmitting HARQ, or processing HARQ to a bearer that supports MBS by default. Alternatively, configuration information of the SDAP entity can not be configured for the first bearer structure by using system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel, and the SDAP entity can not process (for example, bypass) data of the first bearer and can directly transmit the data to the MBS application layer. According to another method, configuration information of the SDAP entity for a bearer can be configured by using system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel, and mapping information between a QoS flow and a bearer can be configured or reconfigured. Furthermore, in the configuration information of the SDAP entity, whether to configure an SDAP header for DL data and whether to configure an SDAP header for UL data can be configured. Furthermore, by using the mapping information between the QoS flow and the bearer, a reconfiguration procedure or a handover procedure between a unicast bearer and a multicast bearer can be supported.Further, in the SDAP configuration information for the bearer, a QoS flow for the MBS can be mapped to a bearer to support the MBS. MBS data to be received or transmitted in the first bearer structure can have a structure of 1g-11 or 1g-12. For example, according to configuration information of a system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel, MBS data to be received or transmitted in the first bearer structure can have a structure of 1g-11 or 1g-12. Based on this configuration, overhead due to a header can be reduced.

[0214] - Second bearer structure 1g-02: when a unicast bearer or a multicast bearer for the MBS is configured as FIG. 1GWhen the second bearer structure 1g-02 is illustrated, the UE can configure an RLC entity corresponding to an MBS control data channel, an MBS user data channel, or a logical channel ID (or MBS) connected to an MBS user data channel of the MAC entity. Further, the UE can configure a bearer structure directly connecting the RLC entity and an upper layer MBS application layer as a bearer of the MBS. In the second bearer structure, a process of transmitting HARQ ACK or NACK, retransmitting HARQ, or processing HARQ of the MAC entity can not be applied to the second bearer. Alternatively, in the second bearer structure, the UE can transmit MBS data (MBS control data or MBS user data) received through the PHY layer or the MAC entity to the upper layer MBS application layer through the RLC entity. In the second bearer structure, the MBS data can not include a MAC header. For example, this is because, when an additional physical channel or transport channel of the MBS is configured, and an additional transmission resource (frequency, time resource, or transmission period) is configured, the MBS data can be identified by the MAC entity without the MAC header. According to another method, for example, this is because, when an additional physical channel or transport channel of the MBS is configured, and an additional transmission resource (frequency, time resource, or transmission period) is configured, and when a first RNTI of the MBS data is allocated or defined, the PHY layer or the MAC entity can identify the MBS data without the MAC header. The RNTI of the MBS data can be allocated or designated with each of a 1-1th RNTI for the MBS control data (or MBS control data channel) and a 1-2th RNTI for the MBS user data (or MBS user data channel, logical channel ID, or MBS). According to another method, in the second bearer structure, when an additional physical channel or transport channel of the MBS is configured, when the MBS is used for DL-SCH support of a general data service, or when an additional transmission resource (frequency, time resource, or transmission period) is configured, the MBS data can include a MAC header, and the PHY layer or the MAC entity can identify the MBS control data (or MBS control data channel), the MBS user data (or MBS user data channel, logical channel ID, or each MBS), or the MBS based on a logical channel ID included in the MAC header, or can demultiplex the identified MBS control data, MBS user data, or MBS and transmit the demultiplexed MBS control data, MBS user data, or MBS to the RLC entity. According to another method, in the second bearer structure, when an additional physical channel or transport channel of the MBS is configured, when the MBS is used for DL-SCH support of a general data service, or when an additional transmission resource (frequency, time resource, or transmission period) is configured, the MBS data can be received via the transmission resource. When a first RNTI of the MBS data is allocated or defined, the MBS data can be received via the transmission resource according to an indication through a PDCCH of the RNTI.The MBS data can include a MAC header, and the MBS control data (or MBS control data channel), MBS user data (or MBS user data channel, logical channel ID, or each MBS) or MBS can be identified based on the logical channel ID included in the MAC header, or the identified MBS control data, MBS user data or MBS can be de-multiplexed and transmitted to each RLC entity. That is, in order to support MBS, a different logical channel ID can be configured or defined for each of the MBS control data channel, MBS user data channel, and MBS. In the second bearer structure, the configured RLC entity can be configured to be in a transparent mode TM, and the MBS data can not include an RLC header. Alternatively, in the RLC entity, the RLC sequence number length can not be configured. Alternatively, the RLC entity can not apply a data processing procedure to the MBS data. Further, the RLC entity configured in the second bearer structure can not apply a procedure for splitting data or recombining data for the MBS data in the TM mode. Alternatively, in the second bearer structure, the configured RLC entity can configure the size of the RLC reception window to 0, or can not operate the RLC reception window. In the second bearer structure, the MAC entity can not apply a procedure of transmitting a HARQ ACK or NACK, retransmitting a HARQ, or processing a HARQ to a bearer that supports MBS by default. Alternatively, the configuration information of the SDAP entity can not be configured for the second bearer structure by using a system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel, and the SDAP entity can not process (e.g., bypass) data of the second bearer and can directly transmit the data to an MBS application layer. According to another method, the configuration information of the SDAP entity for the bearer can be configured by using an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message) or a control message of an MBS channel, and mapping information between a QoS flow and a bearer can be configured or reconfigured. Further, in the configuration information of the SDAP entity, whether to configure an SDAP header for DL data and whether to configure an SDAP header for UL data can be configured. Further, by using the mapping information between the QoS flow and the bearer, a reconfiguration procedure or a switching procedure between a unicast bearer and a multicast bearer can be supported. Further, in the SDAP configuration information for the bearer, a QoS flow for the MBS can be mapped to the bearer to support the MBS. The MBS data to be received or transmitted in the second bearer structure can have a structure of 1g-21. Based on the configuration, the overhead due to the header can be reduced.For example, the MBS data to be received or transmitted in the second bearer structure can have a structure of 1g-21 according to the configuration information of the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel.

[0215] - Third bearer structure 1g-03: when the unicast bearer or the multicast bearer of the MBS is configured as FIG. 1GWhen the third bearer structure 1g-03 is illustrated, the UE can configure an RLC entity corresponding to an MBS control data channel, an MBS user data channel, or a logical channel ID (or MBS) of the MBS user data channel connected to a MAC entity. Further, the UE can configure a bearer structure directly connecting the RLC entity and an upper layer MBS application layer as a bearer of the MBS. In the third bearer structure, a procedure of transmitting a HARQ ACK or NACK, retransmitting a HARQ, or processing a HARQ of the MAC entity can not be applied to the third bearer. According to another method, performing or not performing the procedure of transmitting a HARQ ACK or NACK, retransmitting a HARQ, or processing a HARQ of the MAC entity can be configured via an indicator by a system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel. For example, when an indicator of performing the procedure of transmitting a HARQ ACK or NACK, retransmitting a HARQ, or processing a HARQ of the MAC entity is configured in the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or the newly defined new RRC message), or the control message of the MBS channel (when a value of the indicator indicates a specific value or there is no indicator field), the procedure of transmitting a HARQ ACK or NACK, retransmitting a HARQ, or processing a HARQ of the MAC entity can be performed. Alternatively, when an indicator of not performing the procedure of transmitting a HARQ ACK or NACK, retransmitting a HARQ, or processing a HARQ of the MAC entity is configured (when a value of the indicator indicates a specific value or there is no indicator field), the corresponding procedure can not be performed, or the corresponding procedure (the procedure of transmitting a HARQ ACK or NACK, retransmitting a HARQ, or processing a HARQ of the MAC entity) can not be applied to a bearer that supports the MBS by default. Alternatively, the indicator can be configured for each of the MBS control data channel, the MBS user data channel, the logical channel ID (or MBS) of the MBS user data channel, or a bearer ID.According to another method, when the process of transmitting HARQ ACK or NACK, retransmission HARQ, or processing HARQ of the MAC entity is to be performed or configured to be performed, or is configured for a specific logical channel ID, MBS, or bearer, an indicator (the indicator value can indicate a specific value or can have no indicator field) can be configured via a control message of the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message) or the MBS channel to perform HARQ reordering or RLC reordering (or sequentially deliver) with respect to the RLC entity configured for the logical channel ID (or MBS) of the MBS control data channel, the MBS user data channel, or the MBS user data channel. Alternatively, the size of the RLC reception window can be configured and operated as a value greater than 0 (for example, value = 2^(RLC sequence number length-1)). This is because, when the process of HARQ is performed for MBS data, the order of the data can be mixed, and thus, reordering of the MBS data must be performed based on the RLC reception window or the RLC sequence number, or a reordering timer must be operated to sequentially support the MBS. According to another method, when the process of transmitting HARQ ACK or NACK, retransmission HARQ, or processing HARQ of the MAC entity is not to be performed or configured not to be performed, an indicator (the indicator value can indicate a specific value or can have no indicator field) can be configured via a control message of the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message) or the MBS channel not to perform HARQ reordering or RLC reordering (or sequentially deliver) with respect to the RLC entity configured for the logical channel ID (or MBS) of the MBS control data channel, the MBS user data channel, or the MBS user data channel, so that HARQ reordering or RLC reordering (or sequentially deliver) can not be performed. Alternatively, the process of transmitting HARQ ACK or NACK, retransmission HARQ, or processing HARQ of the MAC entity can not be applied by default to a bearer supporting the MBS, so that the RLC entity configured in the MBS supporting bearer can not perform HARQ reordering or RLC reordering (or sequentially deliver) by default. Alternatively, the size of the RLC reception window can be configured as 0, and thus the reception RLC window can not be operated. For example, when the configuration information is not present or as a default, the UE can always transmit data to the upper layer entity via out-of-order delivery regardless of the order through the RLC entity. Furthermore, in the third bearer structure, the UE can transmit the MBS data (MBS control data or MBS user data) received through the PHY layer or the MAC entity to the upper MBS application layer through the RLC entity.In the third bearer structure, the MBS data can include a MAC header. Alternatively, a logical channel ID included in the MAC header can be configured or defined to indicate the MBS control data channel, the MBS user data channel, or each MBS. For example, when an additional physical channel or transport channel of the MBS is configured and an additional transmission resource (frequency, time resource, or transmission period) is configured, and when a first RNTI for the MBS data is allocated or defined, the PHY layer or the MAC entity can identify whether the MBS data is the MBS control data or the MBS user data, or identify to which MBS the data corresponds, based on the RNTI or the logical channel ID, or can demultiplex the identified data and transmit the demultiplexed data to each RLC entity. The RNTI for the MBS data can be allocated or designated with each of a 1-1th RNTI for the MBS control data (or the MBS control data channel) and a 1-2th RNTI for the MBS user data (or the MBS user data channel, the logical channel ID, or each MBS). According to another method, in the third bearer structure, when an additional physical channel or transport channel of the MBS is configured, when the MBS is used for DL-SCH support of a general data service, or when an additional transmission resource (frequency, time resource, or transmission period) is configured, the MBS data can include a MAC header, and the MBS control data (or the MBS control data channel), the MBS user data (or the MBS user data channel, the logical channel ID, or each MBS), or the MBS can be identified based on a logical channel ID included in the MAC header, or the identified MBS control data, MBS user data, or MBS can be demultiplexed and transmitted to each RLC entity. According to another method, in the third bearer structure, when an additional physical channel or transport channel of the MBS is configured, when the MBS is used for DL-SCH support of a general data service, or when an additional transmission resource (frequency, time resource, or transmission period) is configured, the PHY layer or the MAC entity can receive the MBS data via the transmission resource. When a first RNTI for the MBS data is allocated or defined, the MBS data can be received via the transmission resource according to an indication by a PDCCH through the RNTI. The MBS data can include a MAC header, and the MBS control data (or the MBS control data channel), the MBS user data (or the MBS user data channel, the logical channel ID, or each MBS), or the MBS can be identified based on a logical channel ID included in the MAC header, or the identified MBS control data, MBS user data, or MBS can be demultiplexed and transmitted to each RLC entity. That is, in order to support the MBS, a different logical channel ID can be configured or defined for each of the MBS control data channel, the MBS user data channel, and the MBS. In the third bearer structure, the configured RLC entity can be configured to be in TM, UM, a unidirectional mode of UM, a bidirectional mode of UM, or AM.In the RLC TM, the MBS data can not include the RLC header, and in the RLC UM or AM, the MBS data can include the RLC header. Further, in the RLC TM, the RLC entity can not apply a data processing procedure (e.g., a data segmentation or reassembly procedure) for the MBS data. In the RLC UM or AM, the RLC entity can apply a data processing procedure for the MBS data. Alternatively, by using system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel, configuration information of an SDAP entity can not be configured for a third bearer structure, and the SDAP entity can not process (e.g., bypass) data of the third bearer and can directly transmit the data to an MBS application layer. According to another method, configuration information of an SDAP entity for a bearer can be configured by using an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel, and mapping information between a QoS flow and a bearer can be configured or reconfigured. Further, in the configuration information of the SDAP entity, whether to configure an SDAP header for DL data and whether to configure an SDAP header for UL data can be configured. Further, by using the mapping information between the QoS flow and the bearer, a reconfiguration procedure or a handover procedure between a unicast bearer and a multicast bearer can be supported. Further, in the SDAP configuration information for a bearer, a QoS flow for an MBS can be mapped to a bearer to support the MBS. MBS data to be received or transmitted in the third bearer structure can have a 1g-31 or 1g-32 structure. Based on the configuration, overhead due to a header can be reduced. For example, according to configuration information of system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel, MBS data to be received or transmitted in the third bearer structure can have a 1g-31 or 1g-32 structure. When it is configured via an indicator or configured to perform a procedure of transmitting a HARQ ACK or NACK of a MAC entity, retransmission HARQ, or processing HARQ via system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel, information of a transmission resource (e.g., a time, a frequency resource, a transmission channel, a frequency interval, etc.) for transmitting the HARQ ACK or NACK can also be transmitted.When the UE in the RRC connected mode, the RRC inactive mode or the RRC idle mode is configured to process the procedure of transmitting the HARQ ACK or the NACK of the MAC entity, the retransmission HARQ or the HARQ, the UE can transmit the HARQ ACK or the NACK via the transmission resource (for example, the physical transmission resource) configured after receiving the DL MBS data. When the base station detects at least one NACK or detects that at least one UE transmits the NACK in the transmission resource, the base station can perform the retransmission for the MBS. Alternatively, the base station can perform the retransmission so that all UEs can receive the MBS data through the MBS channel. According to another method, after the UE in the RRC connected mode, the RRC inactive mode or the RRC idle mode receives the DL MBS data, the UE can define the MAC control information (or the RLC control information, the PDCP control information or the RRC message), and can transmit the MAC control information (or the RLC control information, the PDCP control information or the RRC message) by including the UE ID, the MBS ID, the logical channel ID, the RNTI or the bearer ID, so as to indicate to the base station which UE does not successfully receive the data (for example, the MAC control information (or the RLC control information, the PDCP control information or the RRC message) can be transmitted via the configured transmission resource). The base station can perform the retransmission of the MBS data only for the UE in the RRC connected mode, the RRC idle mode or the RRC inactive mode, which transmits the NACK or indicates the unsuccessful reception through the transmission resource. According to another method, when the base station detects at least one NACK or detects that at least one UE transmits the NACK in the transmission resource, the base station can perform the retransmission for the MBS. Alternatively, the base station can perform the retransmission so that all UEs can receive the MBS data through the MBS channel.

[0216] - fourth bearer structure 1g-04: when the unicast bearer or the multicast bearer of the MBS is configured to FIG. 1GWhen the fourth bearer structure 1g-04 is illustrated, the UE can configure an RLC entity corresponding to the MBS control data channel, an MBS user data channel, or a logical channel ID (or MBS) of the MBS user data channel connected to the MAC entity. Further, a PDCP entity connected to the RLC entity can be configured, and a bearer structure directly connecting the PDCP entity and an upper layer MBS application layer can be configured as a bearer of the MBS. In the fourth bearer structure, a procedure of transmitting HARQ ACK or NACK, retransmitting HARQ, or processing HARQ of the MAC entity can not be applied to the fourth bearer. According to another method, performing or not performing the procedure of transmitting HARQ ACK or NACK, retransmitting HARQ, or processing HARQ of the MAC entity can be configured via an indicator by a system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of the MBS channel. For example, when an indicator (when a value of the indicator indicates a specific value or there is no indicator field) of performing the procedure of transmitting HARQ ACK or NACK, retransmitting HARQ, or processing HARQ of the MAC entity is configured in the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or the newly defined new RRC message), or the control message of the MBS channel, the procedure of transmitting HARQ ACK or NACK, retransmitting HARQ, or processing HARQ of the MAC entity can be performed. Alternatively, when an indicator (when a value of the indicator indicates a specific value or there is no indicator field) of not performing the procedure of transmitting HARQ ACK or NACK, retransmitting HARQ, or processing HARQ of the MAC entity is configured, the corresponding procedure can not be performed, or the corresponding procedure (the procedure of transmitting HARQ ACK or NACK, retransmitting HARQ, or processing HARQ of the MAC entity) can not be applied to a bearer that supports the MBS by default. Alternatively, the indicator can be configured for each of the MBS control data channel, the MBS user data channel, the logical channel ID (or MBS) of the MBS user data channel, or a bearer ID.According to another method, when the process of transmitting HARQ ACK or NACK, retransmission HARQ, or processing HARQ of the MAC entity is to be performed or configured to be performed, or is configured for a specific logical channel ID, MBS, or bearer, an indicator (the indicator value can indicate a specific value or can have no indicator field) can be configured via a control message of the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message) or the MBS channel to perform HARQ reordering or RLC reordering (or sequentially deliver) with respect to the RLC entity configured for the logical channel ID (or MBS) of the MBS control data channel, the MBS user data channel, or the MBS user data channel. Alternatively, the size of the RLC reception window can be configured and operated as a value greater than 0 (for example, value = 2^(RLC sequence number length-1)). This is because, when the process of HARQ is performed for MBS data, the order of the data can be mixed, and thus, reordering of the MBS data must be performed based on the RLC reception window or the RLC sequence number, or a reordering timer must be operated to sequentially support the MBS. According to another method, when the process of transmitting HARQ ACK or NACK, retransmission HARQ, or processing HARQ of the MAC entity is not performed or configured not to be performed, an indicator (the indicator value can indicate a specific value or can have no indicator field) can be configured via a control message of the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message) or the MBS channel not to perform HARQ reordering or RLC reordering (or sequentially deliver) with respect to the RLC entity configured for the logical channel ID (or MBS) of the MBS control data channel, the MBS user data channel, or the MBS user data channel, so that HARQ reordering or RLC reordering (or sequentially deliver) can not be performed. Alternatively, the process of transmitting HARQ ACK or NACK, retransmission HARQ, or processing HARQ of the MAC entity can not be applied by default to a bearer supporting MBS, so that the RLC entity configured in the MBS supporting bearer can not perform HARQ reordering or RLC reordering (or sequentially deliver) by default. Alternatively, the size of the RLC reception window can be configured as 0, and thus the reception RLC window can not be operated. For example, when the configuration information is not present or as a default, the UE can always transmit data to the upper layer entity via out-of-order delivery regardless of the order through the RLC entity. Alternatively, in the fourth bearer structure, the UE can transmit the MBS data (MBS control data or MBS user data) received through the PHY layer or the MAC entity to the upper MBS application layer through the RLC entity or the PDCP entity.In the fourth bearer structure, the MBS data can include a MAC header. Alternatively, a logical channel ID included in the MAC header can be configured or defined to indicate the MBS control data channel, the MBS user data channel, or each MBS. For example, when an additional physical channel or transport channel of the MBS is configured, and an additional transmission resource (frequency, time resource, or transmission period) is configured, and when a first RNTI of the MBS data is allocated or defined, the PHY layer or the MAC entity can identify whether the MBS data is the MBS control data or the MBS user data, or identify which MBS the data corresponds to, based on the RNTI or the logical channel ID, or can demultiplex the identified data and transmit the demultiplexed data to each RLC entity. The RNTI of the MBS data can be allocated or designated with each of a 1-1th RNTI for the MBS control data (or the MBS control data channel) and a 1-2th RNTI for the MBS user data (or the MBS user data channel, the logical channel ID, or each MBS). According to another method, in the fourth bearer structure, when an additional physical channel or transport channel of the MBS is configured, when the MBS is used for DL-SCH support of a general data service, or when an additional transmission resource (frequency, time resource, or transmission period) is configured, the MBS data can include a MAC header, and the MAC header can identify the MBS control data (or the MBS control data channel), the MBS user data (or the MBS user data channel, the logical channel ID, or each MBS), or the MBS based on a logical channel ID included in the MAC header, or can demultiplex and transmit the identified MBS control data, MBS user data, or MBS to each RLC entity. According to another method, in the third bearer structure, when an additional physical channel or transport channel of the MBS is configured, when the MBS is used for DL-SCH support of a general data service, or when an additional transmission resource (frequency, time resource, or transmission period) is configured, the PHY layer or the MAC entity can receive the MBS data via the transmission resource. When a first RNTI of the MBS data is allocated or defined, the MBS data can be received via the transmission resource according to an indication by a PDCCH of the RNTI. The MBS data can include a MAC header, and the MAC entity can identify the MBS control data (or the MBS control data channel), the MBS user data (or the MBS user data channel, the logical channel ID, or each MBS), or the MBS based on a logical channel ID included in the MAC header, or can demultiplex and transmit the identified MBS control data, MBS user data, or MBS to each RLC entity. That is, in order to support the MBS, a different logical channel ID can be configured or defined for each of the MBS control data channel, the MBS user data channel, and the MBS.In the fourth bearer structure, the configured RLC entity can be configured in TM, UM, a unidirectional mode of UM, a bidirectional mode of UM, or AM. In the RLC TM, the MBS data can not include the RLC header, and in the RLC UM or AM, the MBS data can include the RLC header. Also, in the RLC TM, the RLC entity can not apply a data processing procedure (e.g., a data segmentation or reassembly procedure) for the MBS data. In the RLC UM or AM, the RLC entity can apply the data processing procedure for the MBS data. For the fourth bearer structure, by using the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel, the RLC entity can be configured in TM, and thus, the overhead of the MBS data can be reduced (e.g., the overhead can be reduced by not using the RLC header). Alternatively, for the fourth bearer structure, by using the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel, the non-sequential delivery function can be configured in the PDCP entity, and thus, the transmission delay of the MBS data can be prevented. According to another method, in the fourth bearer structure for the MBS bearer, the PDCP entity can perform the non-sequential delivery function by default (e.g., an indicator of non-sequential delivery is always configured to be true), and thus, the transmission delay of the MBS data can be prevented. This is because, when the procedure of retransmission or processing HARQ is not performed, and the procedure of retransmission RLC for the MBS data is not performed, when data loss occurs, the reordering function of the PDCP entity can cause the transmission delay. According to another method, the PDCP entity can perform the reordering function of PDCP by default, can determine the size of the reception window based on the PDCP sequence number length (e.g., the PDCP sequence number length is 16 bits, and the window size is 2^(16-1)), and can operate the reordering timer. Alternatively, in the fourth bearer structure, the configuration information of the SDAP entity for the bearer can be configured by using the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel, and the mapping information between the QoS flow and the bearer can be configured or reconfigured. Also, in the configuration information of the SDAP entity, whether to configure the SDAP header for the DL data and whether to configure the SDAP header for the UL data can be configured. Also, by using the mapping information between the QoS flow and the bearer, the reconfiguration procedure or the switching procedure between the unicast bearer and the multicast bearer can be supported.Further, by using the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel, configuration information of the SDAP entity can not be configured for the fourth bearer structure, and the SDAP entity can not process (e.g., bypass) data of the fourth bearer and can directly transmit the data to the MBS application layer. Further, in the SDAP configuration information for the bearer, a QoS flow for the MBS can be mapped to the bearer to support the MBS. The MBS data to be received or transmitted in the fourth bearer structure can have the structure of 1g-41, 1g-42, 1g-43, or 1g-44. For example, according to the configuration information of the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel, the MBS data to be received or transmitted in the fourth bearer structure can have the structure of 1g-41, 1g-42, 1g-43, or 1g-44. Based on this configuration, the overhead due to the header can be reduced. When performing the procedure of transmitting the HARQ ACK or NACK of the MAC entity, the retransmission HARQ, or the processing of the HARQ via the indicator or is configured to perform the procedure of transmitting the HARQ ACK or NACK of the MAC entity, the retransmission HARQ, or the processing of the HARQ via the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel, information of the transmission resource (e.g., time, frequency resource, transmission channel, frequency interval, etc.) for transmitting the HARQ ACK or NACK can also be transmitted. When the UE in the RRC connected mode, the RRC inactive mode, or the RRC idle mode is configured to process the procedure of transmitting the HARQ ACK or NACK of the MAC entity, the retransmission HARQ, or the processing of the HARQ, the UE can transmit the HARQ ACK or NACK via the transmission resource (e.g., physical transmission resource) configured after receiving the DL MBS data. When the base station detects at least one NACK or detects that at least one UE transmits the NACK in the transmission resource, the base station can perform the retransmission for the MBS. Alternatively, the base station can perform the retransmission so that all UEs can receive the MBS data through the MBS channel.According to another method, after a UE in an RRC connected mode, an RRC inactive mode, or an RRC idle mode receives DL MBS data, the UE can define MAC control information (or RLC control information, PDCP control information, or an RRC message) and can transmit the MAC control information (or RLC control information, PDCP control information, or RRC message) by including a UE ID, an MBS ID, a logical channel ID, an RNTI, or a bearer ID in order to indicate to the base station which UE has not successfully received the data (for example, the MAC control information (or RLC control information, PDCP control information, or RRC message) can be transmitted via a configured transmission resource). The base station can perform retransmission of MBS data only for a UE in an RRC connected mode, an RRC idle mode, or an RRC inactive mode that transmits a NACK or indicates unsuccessful reception through a transmission resource. According to another method, when the base station detects at least one NACK or detects that at least one UE transmits a NACK in a transmission resource, the base station can perform retransmission for MBS. Alternatively, the base station can perform retransmission so that all UEs can receive MBS data through an MBS channel.

[0217] When a UE receives system information, is to receive a service of interest, has a service of interest, or determines a system of interest, when the UE is in or enters a cell or a domain in which MBS is supported in system information, when an MBS (or a session) is configured or connected, or when configuration information or bearer configuration information of an MBS is received or broadcast via system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message (for example, transmitted from an MBS control data channel) of an MBS channel, the UE can configure a unicast bearer, a multicast bearer, or an MBS bearer in order to receive an MBS having a provided bearer structure.

[0218] FIG. 1H is a diagram of a method of demultiplexing received MBS data via a MAC layer when a UE in an RRC connected mode, an RRC inactive mode, or an RRC idle mode receives MBS data (for example, MBS control data, MBS user data, or general data other than MBS data) via a multicast bearer or a unicast bearer supporting MBS according to an embodiment of the disclosure.

[0219] In addition, FIG. 1H may be FIG. 1G one of the bearer structures provided in. In addition, a method of transmitting UL MBS data (for example, MBS control data, MBS user data, or general data other than MBS data) by a UE is provided.

[0220] Reference FIG. 1H The method of receiving MBS data or the method of receiving MBS data and demultiplexing MBS data can use one or more of the following methods. According to another method, different methods among the following methods can be applied depending on whether the UE is in an RRC connected mode, an RRC inactive mode, or an RRC idle mode.

[0221] - 1st-1 method of receiving MBS 1h-10: In FIG. 1HIn the 1-1 method of receiving the MBS 1h-10 among them, an additional physical channel or transport channel (e.g., MBS channel (MBCH)) of the MBS can be configured, and an additional transport resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) can be configured or defined in the system information, RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or control message of the MBS channel (e.g., transmitted from the MBS control data channel). The MAC header can always be attached to the MBS data to be transmitted for the MBS, and the logical channel ID included in the MAC header can be differently assigned for each of the MBS control data channel (e.g., MBS control channel (MBCCH)) and the MBS user data channel (e.g., MBS traffic channel (MBTCH)). In addition, a different logical channel ID can be assigned for each MBS provided through the MBS user data channel. A first ID or a second ID of each MBS can be configured or broadcast, and each logical channel ID corresponding to the first ID or the second ID of each MBS can be configured or broadcast in the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel (e.g., transmitted from the MBS control data channel). The first ID can indicate a public land mobile network (PLMN) providing the MBS, a type or session of the MBS. The second ID can indicate a more detailed session or a type of the MBS. In the DL-SCH, a logical channel ID assignable to a bearer of a general data service (voice, Internet, or video service) can be assigned with a specific bit combination (e.g., 6 bits) in a logical channel ID space generated with a specific number of bits (e.g., 6 bits). A logical channel ID for the MBS control data channel, the MBS user data channel, or each service of the MBS user data channel can be assigned with a specific bit combination (e.g., 6 bits) in the first logical channel ID space. Alternatively, MBS control information (MAC CE, e.g., MAC CE for the network to indicate suspension of the MBS or for the UE to indicate stop of reception of the MBS) for supporting the MBS or a logical channel ID for padding for inserting padding into the MBS data to support the MBS can also be assigned with a specific bit combination (e.g., 6 bits) in the first logical channel ID space.According to another method, in order to double the logical channel ID space, the logical channel ID for the MBS control data channel, the MBS user data channel, or the logical channel ID for each service of the MBS user data channel can be allocated with a specific bit combination (e.g., 6 bits) in a new second logical channel ID space. Alternatively, the MBS control information (MAC CE, e.g., MAC CE for network indication of BMS suspension or for UE indication of stop of reception of MBS) for supporting MBS or the logical channel ID for padding for inserting padding for MBS data to support MBS can also be allocated with a specific bit combination (e.g., 6 bits) in a new second logical channel ID space. The first logical channel ID space and the second logical channel ID space can be distinguished from each other in the MAC entity via the MBS channel, the DL-SCH channel, or the transmission resource (frequency, time transmission resource, frequency information, BWP ID, BWP configuration information, dedicated carrier or dedicated SCell ID, or dedicated cell information), or can be distinguished from each other by using different RNTIs from each other. Accordingly, when the MAC entity of the UE receives the MBS data through the channel or the transmission resource via which the MBS is received, the MAC entity can identify the MBS data or demultiplex the identified MBS data based on the received transmission channel (e.g., MBCH, DL-SCH, BCH, etc.), BWP ID, SCell ID, logical channel ID, or RNTI, and transmit the data to the corresponding upper layer entity. The MBS reception method of 1-1 of the first-1 can be applied to the UE in the RRC connected mode, the RRC inactive mode, or the RRC idle mode.

[0222] - reception of MBS 1h-10, the first-2 method: in FIG. 1HIn the 1-2 method of receiving the MBS 1h-10 among them, an additional physical channel or transport channel (e.g., MBCH) of the MBS can be configured, and an additional transport resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) can be configured or defined in the system information, RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or control message of the MBS channel (e.g., transmitted from the MBS control data channel). A MAC header can be attached to the MBS data to be transmitted for the MBS, and a logical channel ID included in the MAC header can be differently allocated for each of the MBS control data channel (e.g., MBCCH) and the MBS user data channel (e.g., MBTCH). In addition, a different logical channel ID can be allocated for each MBS provided through the MBS user data channel. In addition, for each of the MBS control data channel (e.g., MBCCH) and the MBS user data channel (e.g., MBTCH), a different RNTI can be differently allocated. In addition, a different RNTI can be allocated to each MBS provided in the MBS user data channel. Therefore, because the MBS control data channel (e.g., MBCCH), the MBS user data channel, or each MBS provided in the MBS user data channel can be identified by the RNTI, the logical channel ID can be allocated with the same logical channel ID for the MBS control data channel, the MBS user data channel, or each MBS provided in the MBS user data channel. According to another method, the same RNTI can be allocated to the MBS control data channel (e.g., MBCCH), the MBS user data channel, or each MBS provided in the MBS user data channel. And further specific identification can be performed by allocating a different logical channel ID to the MBS control data channel (e.g., MBCCH), the MBS user data channel, or each MBS provided in the MBS user data channel. The RNTI of the MBS can be configured differently from the RNTI (e.g., C-RNTI, MCS-C-RNTI, or CS-RNTI) of the DL-SCH. According to another method, the RNTI of the MBS can be configured to be the same as the RNTI (e.g., C-RNTI, MCS-C-RNTI, or CS-RNTI) of the DL-SCH, and further identification can be performed by the logical channel ID.Further, for each MBS provided in the MBS user data channel, a first ID or a second ID of each MBS can be configured or broadcast, and each logical channel ID or each RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast in system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of the MBS channel (for example, transmitted from the MBS control data channel). The first ID can indicate a PLMN providing the MBS, a type or session of the MBS. The second ID can indicate a more detailed session or type of the MBS. In the DL-SCH, a logical channel ID assignable to a bearer of a general data service (voice, Internet, or video service) can be assigned with a specific bit combination (for example, 6 bits) in a logical channel ID space generated with a specific number of bits (for example, 6 bits). A logical channel ID for each service of the MBS control data channel, the MBS user data channel, or the MBS user data channel can be assigned with a specific bit combination (for example, 6 bits) in a first logical channel ID space. Alternatively, MBS control information (MAC CE, for example, MAC CE for network indication of suspension of the MBS or for UE indication of stop of reception of the MBS) for supporting the MBS or a logical channel ID for padding for inserting padding into MBS data to support the MBS can also be assigned with a specific bit combination (for example, 6 bits) in the first logical channel ID space. According to another method, in order to double the logical channel ID space, a logical channel ID for each service of the MBS control data channel, the MBS user data channel, or the MBS user data channel can be assigned with a specific bit combination (for example, 6 bits) in a new second logical channel ID space. Alternatively, MBS control information (MAC CE, for example, MAC CE for network indication of suspension of the MBS or for UE indication of stop of reception of the MBS) for supporting the MBS or a logical channel ID for padding for inserting padding into MBS data to support the MBS can also be assigned with a specific bit combination (for example, 6 bits) in the new second logical channel ID space. The first logical channel ID space and the second logical channel ID space can be distinguished from each other in the MAC entity via the MBS channel, the DL-SCH channel, or a transmission resource (frequency, time transmission resource, frequency information, BWP ID, BWP configuration information, dedicated carrier, or dedicated SCell ID, or dedicated cell information), or can be distinguished from each other by using different RNTIs from each other.Accordingly, when the MAC entity of the UE receives the MBS data through the channel or transmission resource through which the MBS is received, the MAC entity can identify the MBS data or demultiplex the identified MBS data based on the received transmission channel (e.g., MBCH, DL-SCH, BCH, etc.), BWP ID, SCell ID, logical channel ID, or RNTI, and transmit the data to the corresponding upper layer entity. The MBS reception method of 1-2 can be applied to the UE in the RRC connected mode, RRC inactive mode, or RRC idle mode.

[0223] - 1-3 method of receiving MBS 1h-10: In FIG. 1HIn the 1st-3rd method of receiving the MBS 1h-10 among the above, an additional physical channel or transport channel of the MBS (e.g., MBCH) can be configured, and an additional transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) can be configured or defined in the system information, RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or control message of the MBS channel (e.g., transmitted from the MBS control data channel). In the MBS data transmitted for the MBS, a MAC header can not be attached, and each of the MBS control data channel (e.g., MBCCH) and the MBS user data channel (e.g., MBTCH) can be differently identified based on RNTI. Further, for each of the MBS control data channel (e.g., MBCCH) and the MBS user data channel (e.g., MBTCH), RNTI can be differently assigned. Further, different RNTIs can be assigned for each MBS provided in the MBS user data channel. Accordingly, because the MBS control data channel (e.g., MBCCH), the MBS user data channel, or each MBS provided in the MBS user data channel can be identified by RNTI, a logical channel ID can not necessarily be configured for the MBS control data channel, the MBS user data channel, or each MBS provided in the MBS user data channel, and a MAC header can not necessarily be included in the MBS data. Further, for each MBS provided in the MBS user data channel, a first ID or a second ID of each MBS can be configured or broadcast, and each RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast in the system information, RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or control message of the MBS channel (e.g., transmitted from the MBS control data channel). The first ID can indicate a PLMN providing the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. Accordingly, when the MAC entity of the UE receives the MBS data through a channel or a transmission resource via which the MBS is received, the MAC entity can identify the MBS data or demultiplex the identified MBS data based on the received transport channel (e.g., MBCH, DL-SCH, BCH, etc.), BWP ID, SCell ID, logical channel ID, or RNTI, and transmit the data to a corresponding upper layer entity. The 1st-3rd MBS reception method can be applied to the UE in the RRC connected mode, the RRC inactive mode, or the RRC idle mode.

[0224] - 2nd-1 method of receiving MBS 1h-20: in FIG. 1HIn the 2-1 method of receiving the MBS 1h-20 among them, an additional physical channel or transport channel (e.g., MBCH) of the MBS can be configured, and an additional transport resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) can be configured or defined in the system information, RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or control message of the MBS channel (e.g., transmitted from the MBS control data channel). In the MBS data transmitted for the MBS, a MAC header can always be attached, and a logical channel ID included in the MAC header can be differently allocated for each of the MBS control data channel (e.g., MBCCH) and the MBS user data channel (e.g., MBTCH). Furthermore, a different logical channel ID can be allocated for each MBS provided through the MBS user data channel. A first ID or a second ID of each MBS can be configured or broadcast, and each logical channel ID corresponding to the first ID or the second ID of each MBS can be configured or broadcast in the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel (e.g., transmitted from the MBS control data channel). The first ID can indicate a PLMN providing the MBS, a type or a session of the MBS. The second ID can indicate a more detailed session or a type of the MBS. In the DL-SCH, a logical channel ID that can be allocated to a bearer of a general data service (voice, Internet, or video service) can be allocated with a specific bit combination (e.g., 6 bits) in a logical channel ID space generated with a specific number of bits (e.g., 6 bits). A logical channel ID for each service of the MBS control data channel, the MBS user data channel, or the MBS user data channel can be allocated with a specific bit combination (e.g., 6 bits) in a first logical channel ID space. Alternatively, MBS control information (MAC CE, e.g., MAC CE for network to indicate suspension of the MBS or for UE to indicate stop of reception of the MBS) for supporting the MBS or a logical channel ID for padding for inserting padding into the MBS data to support the MBS can also be allocated with a specific bit combination (e.g., 6 bits) in the first logical channel ID space. According to another method, in order to double the logical channel ID space, a logical channel ID for each service of the MBS control data channel, the MBS user data channel, or the MBS user data channel can be allocated with a specific bit combination (e.g., 6 bits) in a new second logical channel ID space.Alternatively, MBS control information (MAC CE, for example, MAC CE for network indication of BMS suspension or for UE indication of stop of reception of MBS) for supporting MBS or a logical channel ID for padding for inserting padding to MBS data to support MBS can also be allocated in a new second logical channel ID space with a specific bit combination (for example, 6 bits). The first logical channel ID space and the second logical channel ID space can be distinguished from each other in the MAC entity via an MBS channel, a DL-SCH channel, or a transmission resource (frequency, time transmission resource, frequency information, BWP ID, BWP configuration information, a dedicated carrier or a dedicated SCell ID, or dedicated cell information), or can be distinguished from each other by using different RNTIs from each other. Accordingly, when the MAC entity of the UE receives MBS data through a channel or a transmission resource via which MBS is received, the MAC entity can identify MBS data or demultiplex the identified MBS data based on the received transmission channel (for example, MBCH, DL-SCH, BCH, or the like), BWP ID, SCell ID, logical channel ID, or RNTI, and transmit the data to a corresponding upper layer entity. The MBS reception method of 2-1 of the present disclosure can be applied to a UE in an RRC connected mode, an RRC inactive mode, or an RRC idle mode.

[0225] - Method 2-2 of receiving MBS 1h-20: In FIG. 1HIn the 2-2 method of receiving the MBS 1h-20 among them, an additional physical channel or transport channel (e.g., MBCH) of the MBS can be configured, and an additional transport resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) can be configured or defined in the system information, RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or control message of the MBS channel (e.g., transmitted from the MBS control data channel). In the MBS data transmitted for the MBS, a MAC header can be attached, and a logical channel ID included in the MAC header can be differently allocated for each of the MBS control data channel (e.g., MBCCH) and the MBS user data channel (e.g., MBTCH). Further, a different logical channel ID can be allocated for each MBS provided through the MBS user data channel. Further, for each of the MBS control data channel (e.g., MBCCH) and the MBS user data channel (e.g., MBTCH), an RNTI can be differently allocated. Further, a different RNTI can be allocated for each MBS provided in the MBS user data channel. Therefore, because the MBS control data channel (e.g., MBCCH), the MBS user data channel, or each MBS provided in the MBS user data channel can be identified by the RNTI, a logical channel ID can be allocated with the same logical channel ID for the MBS control data channel, the MBS user data channel, or each MBS provided in the MBS user data channel. According to another method, the same RNTI can be allocated to the MBS control data channel (e.g., MBCCH), the MBS user data channel, or each MBS provided in the MBS user data channel. And further specific identification can be performed by allocating a different logical channel ID to the MBS control data channel (e.g., MBCCH), the MBS user data channel, or each MBS provided in the MBS user data channel. The RNTI of the MBS can be differently configured from the RNTI (e.g., C-RNTI, MCS-C-RNTI, or CS-RNTI) of the DL-SCH. According to another method, the RNTI of the MBS can be configured to be the same as the RNTI (e.g., C-RNTI, MCS-C-RNTI, or CS-RNTI) of the DL-SCH, and further identification can be performed by the logical channel ID.Further, for each MBS provided in the MBS user data channel, a first ID or a second ID of each MBS can be configured or broadcast, and each logical channel ID or each RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast in system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of the MBS channel (for example, transmitted from the MBS control data channel). The first ID can indicate a PLMN providing the MBS, a type or a session of the MBS. The second ID can indicate a more detailed session or a type of the MBS. In the DL-SCH, a logical channel ID assignable to a bearer of a general data service (voice, Internet, or video service) can be assigned with a specific combination of bits (for example, 6 bits) in a logical channel ID space generated with a specific number of bits (for example, 6 bits). A logical channel ID for each service of the MBS control data channel, the MBS user data channel, or the MBS user data channel can be assigned with a specific combination of bits (for example, 6 bits) in a first logical channel ID space. Alternatively, MBS control information (MAC CE, for example, a MAC CE for the network to indicate suspension of the MBS or for the UE to indicate stop of reception of the MBS) for supporting the MBS or a logical channel ID for padding for inserting padding into MBS data to support the MBS can also be assigned with a specific combination of bits (for example, 6 bits) in the first logical channel ID space. According to another method, in order to double the logical channel ID space, a logical channel ID for each service of the MBS control data channel, the MBS user data channel, or the MBS user data channel can be assigned with a specific combination of bits (for example, 6 bits) in a new second logical channel ID space. Alternatively, MBS control information (MAC CE, for example, a MAC CE for the network to indicate suspension of the MBS or for the UE to indicate stop of reception of the MBS) for supporting the MBS or a logical channel ID for padding for inserting padding into MBS data to support the MBS can also be assigned with a specific combination of bits (for example, 6 bits) in the new second logical channel ID space. The first logical channel ID space and the second logical channel ID space can be distinguished from each other in the MAC entity via the MBS channel, the DL-SCH channel, or a transmission resource (frequency, time transmission resource, frequency information, BWP ID, BWP configuration information, dedicated carrier or dedicated SCell ID, or dedicated cell information), or can be distinguished from each other by using different RNTIs from each other.Accordingly, when the MAC entity of the UE receives the MBS data through the channel or transmission resource through which the MBS is received, the MAC entity can identify the MBS data or demultiplex the identified MBS data based on the received transmission channel (e.g., MBCH, DL-SCH, BCH, etc.), BWP ID, SCell ID, logical channel ID, or RNTI, and transmit the data to the corresponding upper layer entity. The MBS reception method of 2-2 can be applied to the UE in the RRC connected mode, RRC inactive mode, or RRC idle mode.

[0226] - 2-3 method of receiving MBS 1h-20: In FIG. 1HIn the 2-3 method of receiving the MBS 1h-20 among them, an additional physical channel or transport channel (e.g., MBCH) of the MBS can be configured, and an additional transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) can be configured or defined in the system information, RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or control message (e.g., transmitted from the MBS control data channel) of the MBS channel. In the MBS data transmitted for the MBS, a MAC header can not be attached, and each of the MBS control data channel (e.g., MBCCH) and the MBS user data channel (e.g., MBTCH) can be differently identified based on the RNTI. In addition, for each of the MBS control data channel (e.g., MBCCH) and the MBS user data channel (e.g., MBTCH), the RNTI can be differently assigned. In addition, a different RNTI can be assigned for each MBS provided in the MBS user data channel. Therefore, because the MBS control data channel (e.g., MBCCH), the MBS user data channel, or each MBS provided in the MBS user data channel can be identified by the RNTI, a logical channel ID can not necessarily be configured for the MBS control data channel, the MBS user data channel, or each MBS provided in the MBS user data channel, and a MAC header can not necessarily be included in the MBS data. In addition, for each MBS provided in the MBS user data channel, a first ID or a second ID of each MBS can be configured or broadcast, and each RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast in the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message (e.g., transmitted from the MBS control data channel) of the MBS channel. The first ID can indicate a PLMN providing the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. Therefore, when the MAC entity of the UE receives the MBS data through the channel or the transmission resource via which the MBS is received, the MAC entity can identify the MBS data or demultiplex the identified MBS data based on the received transport channel (e.g., MBCH, DL-SCH, BCH, etc.), BWP ID, SCell ID, logical channel ID, or RNTI, and transmit the data to the corresponding upper layer entity. The MBS reception method of 2-3 can be applied to the UE in the RRC connected mode, the RRC inactive mode, or the RRC idle mode.

[0227] FIG. 1I is a diagram of a method of multiplexing MBS data to be transmitted via a MAC entity according to an embodiment of the disclosure when a UE in an RRC connected mode, an RRC inactive mode, or an RRC idle mode transmits MBS data (e.g., MBS control data, MBS user data, or general data other than MBS data) via a multicast bearer or a unicast bearer supporting MBS.

[0228] Reference FIG. 1I , which is based on the bearer structure provided in FIG. 1G , and the method of transmitting MBS data or the method of transmitting and multiplexing MBS data can use one or more of the following methods. According to another method, different methods among the following methods can be applied depending on whether the UE is in an RRC connected mode, an RRC inactive mode, or an RRC idle mode.

[0229] - First method of transmitting MBS 1i-01: When a UE receiving MBS according to the method provided in FIG. 1H , the UE or the UE in an RRC connected mode, an RRC inactive mode, or an RRC idle mode can transmit UL MBS data to the base station or the network in response to a request of the network or according to the need of the UE. The network or the base station can transmit a network request to the UE by including a network request in MBS data (e.g., MBS control data, MBS user data, an RRC message, RLC control data (RLC control PDU), PDCP control data (PDCP control PDU), MAC control data (MAC CE), or a newly defined message), and can transmit or configure an indication of a state for MBS (e.g., suspension or resumption of service) or information (or an indicator) requesting a response for MBS (e.g., whether the UE is receiving a specific MBS, whether the UE wants to receive a specific MBS, whether the UE is interested in a specific MBS, a preference between a multicast bearer and a unicast bearer, or a preference for bearer conversion (whether the UE wants to receive MBS through a multicast bearer or MBS through a unicast bearer)). The base station or the network can configure a configuration for a network request in FIG. 1HThe additional DL channel, the physical channel of the MBS, the transport channel (e.g., MBCH), or the additional transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) in the system information, the RRC message (e.g., RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel (e.g., transmitted from the MBS control data channel) described above transmits the MBS data including the request of the network so that the UE in the RRC connected mode, the RRC inactive mode, or the RRC idle mode can receive the MBS. As described above, the MBS data can be transmitted via one transmission resource, and a plurality of UEs can receive the MBS data, and thus, waste of the transmission resource can be prevented, and the transmission resource can be efficiently used. According to another method, the base station or the network can configure the MBS data to be transmitted in the additional DL channel, the physical channel of the MBS, the transport channel (e.g., MBCH), or the additional transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) in the system information, the RRC message (e.g., RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel (e.g., transmitted from the MBS control data channel) described above, and transmit the MBS data to the UE in the RRC connected mode, the RRC inactive mode, or the RRC idle mode. FIG. 1HDL channel (e.g., DL-SCH, CCCH, or DCCH), additional transmission resources (frequency, time resources, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing), SRB0 (CCCH), or SRB1 (DCCH) in the described system information or RRC message (e.g., RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or newly defined new RRC message) to transmit UL MBS data including the request of the network so that only the UE in the RRC connected mode can receive the MBS. The UL MBS data can be MBS control data, MBS user data, an RRC message, RLC control data (RLC control PDU), PDCP control data (PDCP control PDU), MAC control data (MAC CE), or a newly defined message. In the first method of transmitting the MBS, the UE can transmit the UL MBS data through an additional UL channel configured in the system information, the RRC message (e.g., RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or newly defined new RRC message), or the control message of the MBS channel (e.g., transmitted from the MBS control data channel), the physical channel of the MBS, the transmission channel (e.g., UL-MBCH), or the additional transmission resources (frequency, time resources, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) of the MBS. For example, the UE can include a MAC header in the UL MBS data, can configure the logical channel ID of the MAC header as a logical channel ID (configured or allocated logical channel ID for MBS control data (channel), MBS user data (channel), MBS user data (channel) for a specific MBS, SRB0 (CCCH), SRB1 (DCCH), DRB, or MAC control information) according to the purpose of the UL MBS data (MBS control data, MBS user data, or MBS user data for a specific MBS), and can transmit the UL MBS data. According to the transmission of the UL MBS data from the UE, the network can transmit the MBS data to the UE through the MBS channel (e.g., DL-MBCH) or the MBS data channel (e.g., MBS control data channel) in the RRC connected mode. FIG. 1GThe bearer structure configured among the bearer structures provided in the middle can further include an RLC header, a PDCP header, or an SDAP header. According to another method, the UE can transmit UL MBS data via an UL transmission resource indicated by a PDCCH with an RNTI configured for the purpose of UL MBS data (MBS control data, MBS user data, or MBS user data for a specific MBS) (an RNTI configured for MBS user data (channel) or MBS user data (channel) for a specific MBS). The UL MBS data can be identified by the RNTI, and thus, can not include a MAC header or a logical channel ID. According to another method, the UL MBS data can include a MAC header, a logical channel ID of the MAC header can be configured as a logical channel ID (a logical channel ID configured or allocated for MBS control data (channel), MBS user data (channel), MBS user data (channel) for a specific MBS, SRB0 (CCCH), SRB1 (DCCH), DRB, or MAC control information) according to the purpose of the UL MBS data (MBS control data, MBS user data, or MBS user data for a specific MBS), and the UL MBS data can be transmitted. According to the method provided in the middle, the UE receiving the MBS must transmit UL MBS data in response to a request of the network or according to the need of the UE, only the UE in an RRC connected mode can transmit the UL MBS data to the base station or the network. The network or the base station can transmit a network request to the UE by including a network request in MBS data (e.g., MBS control data, MBS user data, an RRC message, RLC control data (RLC control PDU), PDCP control data (PDCP control PDU), MAC control data (MAC CE), or a newly defined message), and can transmit or configure an indication (e.g., suspension or resumption of service) of the state for the MBS or information (or an indicator) requesting a response for the MBS (e.g., whether the UE is receiving a specific MBS, whether the UE wants to receive a specific MBS, whether the UE is interested in a specific MBS, a preference between a multicast bearer and a unicast bearer, or a preference for bearer conversion (whether the UE wants to receive an MBS through a multicast bearer or an MBS through a unicast bearer)). The base station or the network can transmit a network request to the UE by configuring a network request in FIG. 1G The bearer structure configured among the bearer structures provided in the middle can further include an RLC header, a PDCP header, or an SDAP header.

[0230] - Second method of transmitting MBS 1i-01: When the method provided in the middle is received according to FIG. 1H The UE receiving the MBS according to the method provided in the middle must transmit UL MBS data in response to a request of the network or according to the need of the UE, only the UE in an RRC connected mode can transmit the UL MBS data to the base station or the network. The network or the base station can transmit a network request to the UE by including a network request in MBS data (e.g., MBS control data, MBS user data, an RRC message, RLC control data (RLC control PDU), PDCP control data (PDCP control PDU), MAC control data (MAC CE), or a newly defined message), and can transmit or configure an indication (e.g., suspension or resumption of service) of the state for the MBS or information (or an indicator) requesting a response for the MBS (e.g., whether the UE is receiving a specific MBS, whether the UE wants to receive a specific MBS, whether the UE is interested in a specific MBS, a preference between a multicast bearer and a unicast bearer, or a preference for bearer conversion (whether the UE wants to receive an MBS through a multicast bearer or an MBS through a unicast bearer)). The base station or the network can transmit a network request to the UE by configuring a network request in FIG. 1HThe additional DL channel, the physical channel of the MBS, the transport channel (e.g., MBCH), or the additional transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing) in the system information, the RRC message (e.g., RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel (e.g., transmitted from the MBS control data channel) described above transmits the MBS data including the request of the network so that the UE in the RRC connected mode, the RRC inactive mode, or the RRC idle mode can receive the MBS. By transmitting the MBS data as described above, the MBS data can be transmitted via one transmission resource, and a plurality of UEs can receive the MBS data. Accordingly, it is possible to prevent waste of the transmission resource, and it is possible to efficiently use the transmission resource. According to another method, the base station or the network can transmit the MBS data including the request of the network by configuring in the system information, the RRC message (e.g., RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel (e.g., transmitted from the MBS control data channel) FIG. 1HDL channel (e.g., DL-SCH, CCCH, or DDCH), additional transmission resources (frequency, time resources, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing), SRB0 (CCCH), or SRB1 (DCCH) in the described system information or RRC message (e.g., RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message) to transmit UL MBS data including the request of the network so that only the UE in the RRC connected mode can receive the MBS. The UL MBS data can be MBS control data, MBS user data, an RRC message, RLC control data (RLC control PDU), PDCP control data (PDCP control PDU), MAC control data (MAC CE), or a newly defined message. In the second method of transmitting the MBS, the UE in the RRC connected mode can transmit the UL MBS data through an additional UL channel configured in the system information, the RRC message (e.g., RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message (e.g., transmitted from the MBS control data channel) of the MBS channel, a physical channel of the MBS, a transmission channel (e.g., UL-SCH, a channel for general data service), additional transmission resources (frequency, time resources, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), or subcarrier spacing), or a transmission resource allocated to a PDCCH scrambled by an RNTI (e.g., C-RNTI) allocated to the UE in the RRC connected mode. When the UE in the RRC connected mode transmits the UL MBS data through the transmission resource allocated to the PDCCH scrambled by the RNTI (e.g., C-RNTI) allocated to the UE in the RRC connected mode, the UE in the RRC connected mode can transmit the UL MBS through SRB0 (CCH), SRB1 (DCCH), or DRB. For example, the UE in the RRC connected mode can include a MAC header in the UL MBS data, can configure a logical channel ID of the MAC header as a logical channel ID (configured or allocated logical channel ID for MBS control data (channel), MBS user data (channel), MBS user data (channel) for a specific MBS, SRB0 (CCCH), SRB1 (DCCH), DRB, or MAC control information) according to the purpose of the UL MBS data (MBS control data, MBS user data, or MBS user data for a specific MBS), and can transmit the UL MBS data. According to the transmission of the UL MBS data from the UE in the RRC connected mode, the network can transmit the MBS data to the UE in the RRC connected mode through the MBS channel (e.g., MBS control data channel, MBS user data channel, or MBS user data channel for a specific MBS) or the transmission resource allocated to the PDCCH scrambled by the RNTI (e.g., C-RNTI) allocated to the UE in the RRC connected mode. FIG. 1GThe bearer structure configured among the bearer structures provided in the middle can further include an RLC header, a PDCP header, or an SDAP header. According to another method, the UE in the RRC connected mode can transmit UL MBS data (MBS control data, MBS user data, or MBS user data for a specific MBS) through an UL transmission resource indicated by a PDCCH via an RNTI (RNTI configured for MBS user data (channel) or MBS user data (channel) for a specific MBS) suitable for the purpose of the UL MBS data (MBS control data, MBS user data, or MBS user data for a specific MBS). The UL MBS data can be identified by the RNTI, and thus, can not include a MAC header or a logical channel ID. According to another method, the UL MBS data can include a MAC header, a logical channel ID of the MAC header can be configured as a logical channel ID (logical channel ID configured or allocated for MBS control data (channel), MBS user data (channel), MBS user data (channel) for a specific MBS, SRB0 (CCCH), SRB1 (DCCH), DRB, or MAC control information) according to the purpose of the UL MBS data (MBS control data, MBS user data, or MBS user data for a specific MBS), and the UL MBS data can be transmitted. According to the purpose of the UL MBS data (MBS control data, MBS user data, or MBS user data for a specific MBS) from FIG. 1G The bearer structure configured among the bearer structures provided in the middle can further include an RLC header, a PDCP header, or an SDAP header.

[0231] Next, a signaling procedure for a base station or a network to support MBS for a UE and for a UE to receive MBS is provided according to the disclosure. As described hereinafter according to the disclosure, through one of various signaling procedures, a base station can provide MBS for a UE, or a UE can receive MBS.

[0232] FIG. 1J is a diagram of a first signaling procedure to support MBS according to an embodiment of the disclosure.

[0233] The first signaling procedure to support MBS according to an embodiment of the disclosure can support MBS for a UE based on system information.

[0234] Referring to FIG. 1J , the UE 1j-01 can perform cell selection or reselection in an RRC idle mode or an RRC inactive mode, can select an appropriate cell, and can camp on the cell. Then, the UE 1j-01 can receive system information 1j-05 from the gNB 1j-02 in the RRC idle mode, the RRC inactive mode, or the RRC connected mode, and can identify some configuration information of MBS from the system information. The configuration information of MBS can include the following configuration information. That is, to support MBS, the network can transmit system information including some of the following configuration information.

[0235] - whether MBS is supported.

[0236] - configuration information of a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) for MBS.

[0237] - information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) is transmitted.

[0238] - configuration information on MBS supported by a current cell. For example, a list of MBSs or a first ID (e.g., temporary mobile group identity (TMGI)) or a second ID (e.g., session identity) of each MBS can be configured or broadcast, and information on a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identity) or an RNTI of MBS can be configured or broadcast for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identity) or an RNTI of MBS can be configured or broadcast for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information. The first ID can indicate a PLMN providing the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for MBS can include information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0239] A bearer can be configured to FIG. 1GThe configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in an RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0240] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0241] - information about an MBS-specific carrier or cell (Cell, SCell, or PCell) of an MBS (for example, a frequency, a time resource, or a cell ID).

[0242] - MBS-specific BWP information (for example, DL BWP information or UL BWP information) or BWP ID information of an MBS.

[0243] - indicator information configuring a header compression function or procedure for a bearer supporting an MBS (in the disclosure, a header compression procedure (for example, robust header compression (ROHC), Ethernet header compression (EHC), or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (for example, an indicator indicating whether to further use a header compression context)).

[0244] - In the above-described configuration information, the length of a PDCP sequence number or an RLC sequence number can also be configured, and according to another method, a default length of an RLC sequence number or a PDCP sequence number can be defined.

[0245] - In the above configuration information, an indicator indicating whether the RLC entity of the bearer supporting the MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0246] When the configuration information of the MBS in the camped cell is not broadcast via system information, the UE can transmit a message or an indicator requesting the broadcast of the system information of the MBS in the camped cell to the base station, the cell, or the network. When the base station or the network receives the message or the indicator, the base station or the network can broadcast or transmit the configuration information of the MBS by using the system information. By doing so, the base station can prevent the waste of transmission resources that can occur when the MBS-related system information is unnecessarily and continuously broadcast.

[0247] The UE receiving the system information 1j-05 can store or apply the MBS configuration information, can search for or determine the MBS in which the UE is interested or the UE wants to receive, and can receive the MBS data (MBS control data or MBS user data) through the transmission resource through which the MBS control data channel or the MBS user data channel for the MBS in which the UE is interested is transmitted. When the UE receives the system information, wants to receive the service of interest, has the service of interest, or determines the system of interest, when the UE is in or enters the cell or the domain in which the MBS is supported in the system information, when the MBS (or session) is configured or connected, or when the configuration information of the MBS or the bearer configuration information is received or broadcast via the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel (for example, transmitted from the MBS control data channel), the UE can configure the unicast bearer, the multicast bearer, or the MBS bearer in order to receive the MBS having the provided bearer structure.

[0248] The UE can receive the MBS configuration data (1j-10) by receiving the MBS data (for example, MBS control data) with respect to the MBCCH or the transmission resource of the MBS in which the UE is interested.

[0249] The MBS configuration information can be transmitted by including some of the following configuration information supporting the MBS.

[0250] - Whether the MBS is supported.

[0251] - Configuration information on the physical channel or the DL or UL transport channel (for example, MBCH, MBCCH, MBTCH, or DL-SCH) of the MBS.

[0252] - Information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) is transmitted.

[0253] - Configuration information on an MBS supported by a current cell. For example, a list of MBSs or a first ID (e.g., TMGI) or a second ID (e.g., session identification) of each MBS can be configured or broadcast, and information on a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identification) or an RNTI of an MBS can be configured or broadcast for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information. The first ID can indicate a PLMN providing the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0254] A bearer can be configured to FIG. 1GThe configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in an RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0255] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0256] - information about an MBS-specific carrier or cell (Cell, SCell, or PCell) of an MBS (for example, a frequency, a time resource, or a cell ID).

[0257] - MBS-specific BWP information (for example, DL BWP information or UL BWP information) or BWP ID information of an MBS.

[0258] - indicator information configuring a header compression function or procedure for a bearer supporting an MBS (in the disclosure, a header compression procedure (for example, ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (for example, an indicator indicating whether to further use a header compression context)).

[0259] - In the above-described configuration information, the length of a PDCP sequence number or an RLC sequence number can also be configured, and according to another method, a default length of an RLC sequence number or a PDCP sequence number can be defined.

[0260] - In the above configuration information, an indicator indicating whether an RLC entity of a bearer supporting MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0261] When the UE receives the MBS configuration information, in order to receive the MBS of interest to the UE or to be received by the UE, the UE can identify the first ID, the second ID, the RNTI, or the logical channel ID configured or allocated for the MBS of interest to the UE or to be received by the UE, and by using the identified ID, the UE can receive the MBS data through the MBS user data channel and receive the MBS by applying the method provided in the disclosure FIG. 1G or 1H.

[0262] FIG. 1K is a diagram of a second signaling procedure supporting MBS according to an embodiment of the disclosure.

[0263] In the second signaling procedure supporting MBS according to the disclosure, the UE can identify the MBS of interest to the UE or broadcasted based on the system information, establish a connection with the network, and indicate the MBS of interest to the UE or the intention to receive the MBS to the base station (or network), receive the MBS-related configuration information from the base station (or network), and receive the MBS. In the second signaling procedure, the UE can maintain the RRC idle mode, the RRC connected mode, or the RRC inactive mode (for example, the UE can receive the MBS without transitioning the RRC mode). According to another method, the UE can enter the RRC connected mode from the RRC idle mode or the RRC inactive mode in order to indicate the MBS of interest to the UE or the intention to receive the MBS to the base station (or network), and receive the MBS configuration information from the base station (or network). Alternatively, after the UE receives the MBS configuration information, the UE can receive the MBS in the RRC connected mode, or can receive the MBS in the RRC idle mode or the RRC inactive mode.

[0264] Referring to FIG. 1K , the UE 1k-01 can perform cell selection or reselection in the RRC idle mode or the RRC inactive mode, can select an appropriate cell, and can camp on the cell. Then, the UE 1k-01 can receive the system information 1k-05 from the gNB 1k-02 in the RRC idle mode, the RRC inactive mode, or the RRC connected mode, and can receive some configuration information of the MBS from the system information. The configuration information of the MBS can include the following configuration information. That is, in order to support the MBS, the network can transmit the system information including some of the following configuration information.

[0265] - Whether the MBS is supported.

[0266] - configuration information for a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) for the MBS.

[0267] - information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) for the MBS is transmitted.

[0268] - configuration information on an MBS supported by a current cell. For example, a list of MBSs or a first ID (e.g., TMGI) or a second ID (e.g., session identification) of each MBS can be configured or broadcast, and information on a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identification) or an RNTI of an MBS can be configured or broadcast for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information. The first ID can indicate a PLMN providing the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0269] A bearer can be configured as FIG. 1GThe configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in an RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0270] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0271] - information about an MBS-specific carrier or cell (Cell, SCell, or PCell) of an MBS (for example, a frequency, a time resource, or a cell ID).

[0272] - MBS-specific BWP information (for example, DL BWP information or UL BWP information) or BWP ID information of an MBS.

[0273] - indicator information configuring a header compression function or procedure for a bearer supporting an MBS (in the disclosure, a header compression procedure (for example, ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (for example, an indicator indicating whether to further use a header compression context)).

[0274] - In the above-described configuration information, the length of a PDCP sequence number or an RLC sequence number can also be configured, and according to another method, a default length of an RLC sequence number or a PDCP sequence number can be defined.

[0275] - In the above configuration information, an indicator indicating whether an RLC entity of a bearer supporting an MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0276] When the configuration information of the MBS in the camped cell is not broadcast via system information, the UE can transmit a message or an indicator requesting the system information of the MBS in the camped cell to the base station, the cell, or the network. When the base station or the network receives the message or the indicator, the base station or the network can broadcast or transmit the configuration information of the MBS by using the system information. By doing so, the base station can prevent the waste of transmission resources that can occur when the MBS-related system information is unnecessarily and continuously broadcast.

[0277] A UE that receives or identifies MBS-related information via system information, a UE that identifies, via system information, that an MBS in which the UE is interested is being broadcast in a current cell, or a UE that is to request an MBS in which the UE is interested from a network can perform a random access procedure and transmit a first RRC message to the network. The first RRC message can be a newly defined RRC message for the MBS or can be defined as an RRCSetupRequest message, an RRCResumeRequest message, a previous other RRC message, MAC control information, RLC control information, or PDCP control information. The UE can include, in the first RRC message, an indicator indicating that the UE is to receive an MBS, an indicator indicating that the MBS is received to establish an RRC connection with the network, or a first ID, a second ID, a logical channel ID, an RNTI, or a bearer ID of the MBS in which the UE is interested or the UE is to receive. The UE can include, in the first RRC message, a bearer type (e.g., a unicast bearer or a multicast bearer) or a bearer structure that is applied, established, or used for the MBS, or a preferred bearer type (e.g., a unicast bearer or a multicast bearer) or a preferred bearer structure, or an indicator indicating in which RRC mode (an RRC connected mode, an RRC idle mode, or an RRC inactive mode) the UE wants to receive the MBS. Alternatively, the UE can transmit the first RRC message by including, in the first RRC message, an indicator for an MBS in which the UE is no longer interested, the UE is to stop receiving, or the UE has stopped receiving, or an indicator indicating a switch to another MBS. The indicator included in the first RRC message by the UE can be determined or indicated based on system information received in 1k-05. In addition, the first RRC message can include UE capability information. For example, when the UE is to receive an MBS, the UE can include, in the first RRC message, configuration information about a function or configuration supported by a UE capability or about a function or configuration implemented in the UE, and can transmit the first RRC message to notify a base station. When the UE previously configures a connection, stores a UE ID allocated from a network, or is instructed by an upper entity (e.g., an NAS entity or an RRC entity) to indicate a UE ID, the UE can include the UE ID in the first RRC message and transmit the first RRC message so that the network can distinguish or identify the UE. For example, the base station or the network can identify the UE based on the UE ID included in the first RRC message, can identify the UE by retrieving UE capability information from a core network, or can identify the UE by retrieving configuration information of the UE from a base station to which the UE previously connects. When the UE receives system information, is to receive a service in which the UE is interested, has a service in which the UE is interested, or determines a system in which the UE is interested, when the UE is in or enters a cell or a domain in which an MBS is supported in the system information, or when an MBS (or a session) is configured or connected, the UE can configure a connection with the network and transmit the first RRC message (1k-10).

[0278] In the procedure of 1k-10, when the base station receives the first RRC message, the base station can identify the MBS in which the UE is interested or the UE wants to receive or UE capability information.

[0279] The base station or network can transmit a second RRC message 1k-15 to the UE in order to support or configure the MBS for the UE (1k-15). The second RRC message can be a newly defined RRC message for the MBS, or can be defined as an RRCRelease message, an RRCReconfiguration message, or a previous other RRC message.

[0280] The second RRC message can include configuration information for the MBS, MBS configuration information or bearer configuration information indicated by the UE in the first RRC message, or configuration information about unicast bearer, multicast bearer, or MBS bearer for receiving the MBS.

[0281] The second RRC message can be transmitted by including some of the following configuration information supporting the MBS.

[0282] - Whether the MBS is supported.

[0283] - Configuration information about a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) for the MBS.

[0284] - Information about a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) for the MBS is transmitted.

[0285] - Configuration information about MBS supported by the current cell. For example, a list of MBSs or a first ID (e.g., TMGI) or a second ID (e.g., session identification) of each MBS can be configured or broadcast, and information about a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identification) or an RNTI of MBSs can be configured or broadcast for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information. The first ID can indicate a PLMN that provides the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information about a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0286] The bearer can be configured as FIG. 1G the bearer structure provided in the above, to receive the MBS. In addition, the configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in the RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0287] - Indicator configuration information indicating whether a bearer or a bearer ID that supports (transmits or receives) the MBS is a unicast bearer or a multicast bearer.

[0288] - an indicator or configuration information indicating a transition to an RRC idle mode, an RRC inactive mode, or an RRC connected mode.

[0289] - MBS configuration information or bearer configuration information provided for receiving an MBS in an RRC idle mode.

[0290] - MBS configuration information or bearer configuration information provided for receiving an MBS in an RRC inactive mode.

[0291] - information on an MBS dedicated carrier or cell (Cell, SCell, or PCell) of an MBS (for example, a frequency, a time resource, or a cell ID).

[0292] - MBS dedicated BWP information (for example, DL BWP information or UL BWP information) or BWP ID information of an MBS.

[0293] - information on an indicator configuring a header compression function or procedure for a bearer supporting an MBS (in the disclosure, a header compression procedure (for example, ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (for example, an indicator indicating whether to further use a header compression context)).

[0294] - In the above configuration information, the length of a PDCP sequence number or an RLC sequence number can also be configured, and according to another method, a default length of an RLC sequence number or a PDCP sequence number can be defined.

[0295] - In the above configuration information, an indicator indicating whether an RLC entity of a bearer supporting an MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0296] The UE receiving the second RRC message can store or apply the MBS-related configuration information, can search for or determine the MBS in which the UE is interested or the UE wants to receive, and can receive the MBS data (MBS control data or MBS user data) through the transmission resource through which the MBS control data channel or the MBS user data channel for the MBS in which the UE is interested is transmitted. When the UE receives the system information, is to receive the service in which the UE is interested, has the service in which the UE is interested, or determines the system in which the UE is interested, when the UE is in or enters the cell or the domain in which the MBS is supported in the system information, when the MBS (or session) is configured or connected, or when the configuration information or the bearer configuration information of the MBS is received or broadcast via the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message (for example, transmitted from the MBS control data channel) of the MBS channel, the UE can configure the unicast bearer, the multicast bearer, or the MBS bearer in order to receive the MBS having the provided bearer structure.

[0297] The UE can receive the MBS configuration data through the received MBS data (for example, the MBS control data) with respect to the MBCCH or the transmission resource of the MBS in which the UE is interested.

[0298] When the UE receives the MBS configuration information, in order to receive the MBS in which the UE is interested or the MBS that the UE wants to receive, the UE can identify the first ID, the second ID, the RNTI, or the logical channel ID configured or allocated with respect to the MBS in which the UE is interested or the MBS that the UE wants to receive, and by using the identified ID, can receive the MBS data through the MBS user data channel and can receive the MBS by applying the method provided in the present disclosure FIG. 1G or 1H.

[0299] The ciphering processing or the integrity protection processing can not be applied to the first RRC message or the second RRC message. According to another method, in order to enhance security, the ciphering processing or the integrity protection processing can not be applied to the first RRC message or the second RRC message, and the ciphering processing or the integrity protection processing can be applied to the first RRC message or the second RRC message. According to another method, in order to further enhance security, the ciphering processing or the integrity protection processing can be applied to the first RRC message or the second RRC message, and the ciphering processing or the integrity protection processing can be applied to the first RRC message or the second RRC message.

[0300] FIG. 1L is a diagram of a third signaling procedure supporting an MBS according to an embodiment of the present disclosure.

[0301] In the third signaling procedure supporting MBS according to the disclosure, the UE can identify the MBS that the UE is interested in or broadcast based on the system information, establish a connection with the network, and indicate to the base station (or network) the MBS that the UE is interested in or the UE wants to receive or the intention to receive the MBS, receive the MBS-related configuration information from the base station (or network), and receive the MBS. In the third signaling procedure, the UE can remain in the RRC idle mode, the RRC connected mode, or the RRC inactive mode. According to another method, the UE can enter the RRC connected mode from the RRC idle mode or the RRC inactive mode in order to indicate to the base station (or network) the MBS that the UE is interested in or the UE wants to receive or the intention to receive the MBS, and receive the MBS configuration information from the base station (or network). Alternatively, after the UE receives the MBS configuration information, the UE can receive the MBS in the RRC connected mode, or can receive the MBS in the RRC idle mode or the RRC inactive mode.

[0302] Reference FIG. 1L , the UE 1l-01 can perform cell selection or reselection in the RRC idle mode or the RRC inactive mode, can select an appropriate cell, and can camp on the cell. Then, the UE 1l-01 can receive system information 1l-05 from the gNB 1l-02 in the RRC idle mode, the RRC inactive mode, or the RRC connected mode, and can receive some configuration information of the MBS from the system information. The configuration information of the MBS can include some of the following configuration information. That is, in order to support the MBS, the network can transmit the system information including some of the following configuration information.

[0303] - Whether the MBS is supported.

[0304] - Configuration information of a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) for the MBS.

[0305] - Information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) is transmitted.

[0306] - Configuration information about MBS supported by the current cell. For example, a list of MBSs or a first ID (e.g., TMGI) or a second ID (e.g., session identification) of each MBS can be configured or broadcast, and information about a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identification) or an RNTI of each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information can be configured or broadcast. The first ID can indicate a PLMN that provides the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information about a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0307] The bearer can be configured as FIG. 1G the bearer structure provided in the above, to receive the MBS. In addition, the configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in the RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0308] - Indicator configuration information indicating whether a bearer or a bearer ID that supports (transmits or receives) the MBS is a unicast bearer or a multicast bearer.

[0309] - Information on an MBS dedicated carrier or cell (Cell, SCell, or PCell) of the MBS (e.g., a frequency, a time resource, or a cell ID).

[0310] - MBS dedicated BWP information (e.g., DL BWP information or UL BWP information) or BWP ID information of the MBS.

[0311] - Indicator information configuring a header compression function or procedure for a bearer supporting the MBS (In the disclosure, a header compression procedure (e.g., ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (e.g., an indicator indicating whether to further use a header compression context)).

[0312] - In the above configuration information, the length of a PDCP sequence number or an RLC sequence number can also be configured, and according to another method, a default length of an RLC sequence number or a PDCP sequence number can be defined.

[0313] - In the above configuration information, an indicator indicating whether an RLC entity of a bearer supporting the MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0314] When the configuration information of the MBS in the camped cell is not broadcast via system information, the UE can transmit a message or an indicator requesting to broadcast system information of the MBS in the camped cell to the base station, the cell, or the network. When the base station or the network receives the message or the indicator, the base station or the network can broadcast or transmit the configuration information of the MBS by using the system information. By doing so, the base station can prevent the waste of transmission resources that can occur when MBS-related system information is unnecessarily and continuously broadcast.

[0315] The UE that receives or identifies the MBS-related information via the system information, the UE that identifies the MBS that the UE is interested in is being broadcast in the current cell via the system information, or the UE that is to request the network for the MBS that the UE is interested in can perform a random access procedure and transmit a first RRC message to the network. The first RRC message can be a newly defined RRC message for the MBS, or can be defined as an RRCSetupRequest message, an RRCResumeRequest message, or a previous other RRC message. The UE can include an indicator indicating that the UE is to receive the MBS or an indicator indicating the reception of the MBS to establish an RRC connection with the network in the first RRC message, or when the UE previously configures a connection, when the UE stores a UE ID (e.g., a UE ID (5G-S-TMSI) allocated from a core network or a UE ID (short I-RNTI or I-RNTI) allocated from a base station for resuming an RRC connection) allocated from the network, or when the UE ID is indicated by an upper layer entity (e.g., an NAS entity or an RRC entity), the UE can transmit the first RRC message by including the UE ID in the first RRC message so that the network can distinguish or identify the UE. For example, the base station or the network can identify the UE based on the UE ID included in the first RRC message, can identify the UE by retrieving UE capability information from a core network, or can identify the UE by retrieving configuration information of the UE from a base station to which the UE previously connects. When the UE receives the system information, is to receive a service of interest, has a service of interest, or determines a system of interest, when the UE is in or enters a cell or a domain that supports the MBS in the system information, or when the MBS (or session) is configured or connected, the UE can configure a connection with the network and transmit the first RRC message.

[0316] In the procedure of 1l-10, when the base station receives the first RRC message, the base station can identify the MBS that the UE is interested in or the UE is to receive or UE capability information.

[0317] The base station or the network can transmit a second RRC message 1l-15 to the UE so as to support or configure the MBS for the UE. The second RRC message can be a newly defined RRC message for the MBS, or can be defined as an RRCRelease message, an RRCReconfiguration message, or a previous other RRC message.

[0318] The second RRC message can include configuration information for the MBS, MBS configuration information or bearer configuration information indicated by the UE in the first RRC message, or configuration information about a unicast bearer, a multicast bearer, or an MBS bearer for receiving the MBS.

[0319] The second RRC message can be transmitted by including some of the following configuration information supporting the MBS.

[0320] - whether the MBS is supported.

[0321] - configuration information on a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) for the MBS.

[0322] - information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) for the MBS is transmitted.

[0323] - configuration information on the MBS supported by the current cell. For example, a list of MBSs or a first ID (e.g., temporary mobile group identity (TMGI)) or a second ID (e.g., session identity) for each MBS can be configured or broadcast, and information on a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID for each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identity) or an RNTI for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information can be configured or broadcast. The first ID can indicate a PLMN providing the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0324] The bearer can be configured to FIG. 1GThe configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in an RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0325] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0326] - information about an MBS-specific carrier or cell (Cell, SCell, or PCell) of an MBS (for example, a frequency, a time resource, or a cell ID).

[0327] - MBS-specific BWP information (for example, DL BWP information or UL BWP information) or BWP ID information of an MBS.

[0328] - information about an indicator configuring a header compression function or procedure for a bearer supporting an MBS (in the disclosure, a header compression procedure (for example, ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (for example, an indicator indicating whether to further use a header compression context)).

[0329] - In the above-described configuration information, the length of a PDCP sequence number or an RLC sequence number can also be configured, and according to another method, a default length of an RLC sequence number or a PDCP sequence number can be defined.

[0330] - In the above configuration information, an indicator indicating whether the RLC entity of the bearer supporting the MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0331] When the UE receives the system information, is going to receive a service of interest, has a service of interest, or determines a system of interest, when the UE is in or enters a cell or domain in which the MBS is supported in the system information, when the MBS (or session) is configured or connected, or when the configuration information of the MBS or the bearer configuration information is received or broadcast via the system information, the RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or the control message of the MBS channel (for example, transmitted from the MBS control data channel), the UE can configure a unicast bearer, a multicast bearer, or an MBS bearer in order to receive the MBS having the provided bearer structure.

[0332] When the UE receives the second RRC message, the UE can apply the configuration information included in the second RRC message, and in response, can transmit a third RRC message (for example, RRCSetupComplete or RRCResumecomplete) to the base station or the network (1l-20).

[0333] The UE can include in the third RRC message an indicator indicating that the UE is to receive the MBS, an indicator indicating that the MBS is received to establish the RRC connection with the network, or a first ID, a second ID, a logical channel ID, an RNTI, or a bearer ID of the MBS of interest to the UE or to be received by the UE.

[0334] The UE can include in the first RRC message or the third RRC message an indicator indicating the bearer type (for example, a unicast bearer or a multicast bearer) or the bearer structure applied, established, or used for the MBS, or a preferred bearer type (for example, a unicast bearer or a multicast bearer) or a preferred bearer structure, or an indicator indicating in which RRC mode (RRC connected mode, RRC idle mode, or RRC inactive mode) the UE wants to receive the MBS. Alternatively, the UE can transmit the first RRC message or the third RRC message by including in the first RRC message or the third RRC message an indicator for the MBS that is no longer of interest to the UE, that the UE wants to stop receiving, or that the UE has stopped receiving, or an indicator indicating that the MBS is switched to another MBS. The indicator included by the UE in the first RRC message or the third RRC message can be determined or indicated based on the system information received in 1l-05.

[0335] The base station can transmit, to the UE, a fourth RRC message (e.g., RRCReconfiguration 1l-30) based on the preference reported by the UE, the indicator indicated by the UE, or an embodiment of the base station to support the MBS, to configure or reconfigure a bearer through which the UE receives the MBS, or to configure or reconfigure MBS-related configuration information. For example, the fourth RRC message can include configuration information for changing a bearer type (e.g., an indicator to convert a unicast bearer into a multicast bearer, an indicator to convert a multicast bearer into a unicast bearer, or bearer configuration information corresponding thereto), or logical channel ID information, RNTI information, or first ID or second ID information of the MBS that is changed or updated for each MBS.

[0336] The fourth RRC message includes some of the following information.

[0337] - Whether the MBS is supported.

[0338] - Configuration information on a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) of the MBS.

[0339] - Information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) of the MBS is transmitted.

[0340] - Configuration information on the MBS supported by the current cell. For example, a list of MBSs or a first ID (e.g., a temporary mobile group identity (TMGI)) or a second ID (e.g., a session identity) of each MBS can be configured or broadcast, and information on a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast. According to another method, a first ID (e.g., a TMGI) or a second ID (e.g., a session identity) or an RNTI of the MBS can be configured or broadcast for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information. The first ID can indicate a PLMN that provides the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0341] The bearer can be configured as FIG. 1G The configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in an RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0342] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0343] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0344] - an indicator or configuration information indicating a transition to an RRC idle mode, an RRC inactive mode, or an RRC connected mode.

[0345] - MBS configuration information or bearer configuration information provided for receiving an MBS in an RRC idle mode.

[0346] - MBS configuration information or bearer configuration information provided for receiving an MBS in an RRC inactive mode.

[0347] - information about an MBS-specific carrier or cell (Cell, SCell, or PCell) of an MBS (for example, a frequency, a time resource, or a cell ID).

[0348] - MBS-specific BWP information (for example, DL BWP information or UL BWP information) or BWP ID information of an MBS.

[0349] - Information on an indicator configuring a header compression function or procedure for a bearer supporting MBS (In the disclosure, a header compression procedure (e.g., ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (e.g., an indicator indicating whether to further use a header compression context)).

[0350] - In the above configuration information, the length of the PDCP sequence number or the RLC sequence number can also be configured, and according to another method, the default length of the RLC sequence number or the PDCP sequence number can be defined.

[0351] - In the above configuration information, an indicator indicating whether the RLC entity of the bearer supporting MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0352] After the UE receives the fourth RRC message and stores or applies the MBS-related configuration information, the UE can configure a fifth RRC message (e.g., RRCReconfigurationComplete 1l-35) indicating successful configuration or reconfiguration, and transmit the fifth RRC message to the base station.

[0353] When the UE receives the MBS configuration information, in order to receive the MBS in which the UE is interested or the UE wants to receive in the RRC connected mode, the UE can identify the first ID, the second ID, the RNTI, or the logical channel ID configured or allocated for the MBS in which the UE is interested or the UE wants to receive, and by using the identified ID, the UE can receive the MBS data through the MBS user data channel and receive the MBS by applying the method provided in the disclosure FIG. 1G or 1H (1l-40).

[0354] The UE can receive the MBS configuration data by receiving the MBS data (e.g., MBS control data) through the MBCCH or the transmission resource for the MBS in which the UE is interested.

[0355] When the base station wants to transition the UE to the RRC inactive mode or the RRC idle mode (e.g., according to the request or the indication of the UE by the base station's embodiment), the base station can configure a sixth RRC message (e.g., RRCRelease 1l-45) and transmit the sixth RRC message to the UE to transition the UE to the RRC idle mode or the RRC inactive mode. The sixth RRC message 1l-45 can include the following information or some of the following information, so that the UE can continuously receive the MBS even in the RRC idle mode or the RRC inactive mode.

[0356] - Whether the MBS is supported.

[0357] - configuration information about a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) of the MBS.

[0358] - information about a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) is transmitted.

[0359] - configuration information about an MBS supported by a current cell. For example, a list of MBSs or a first ID (e.g., TMGI) or a second ID (e.g., session identification) of each MBS can be configured or broadcast, and information about a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identification) or an RNTI of an MBS can be configured or broadcast for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information. The first ID can indicate a PLMN providing the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information about a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0360] A bearer can be configured to FIG. 1GThe configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in an RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0361] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0362] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0363] - an indicator or configuration information indicating a transition to an RRC idle mode, an RRC inactive mode, or an RRC connected mode.

[0364] - MBS configuration information or bearer configuration information provided for receiving an MBS in an RRC idle mode.

[0365] - MBS configuration information or bearer configuration information provided for receiving an MBS in an RRC inactive mode.

[0366] - information about an MBS-specific carrier or cell (Cell, SCell, or PCell) of an MBS (for example, a frequency, a time resource, or a cell ID).

[0367] - MBS-specific BWP information (for example, DL BWP information or UL BWP information) or BWP ID information of an MBS.

[0368] - information on an indicator configuring a header compression function or procedure for a bearer supporting MBS (in the disclosure, a header compression procedure (e.g., ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (e.g., an indicator indicating whether to further use a header compression context)).

[0369] - In the above configuration information, the length of the PDCP sequence number or the RLC sequence number can also be configured, and according to another method, the default length of the RLC sequence number or the PDCP sequence number can be defined.

[0370] - In the above configuration information, an indicator indicating whether the RLC entity of the bearer supporting MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0371] When the UE receives the MBS configuration information, in order to receive the MBS of interest to the UE or to be received by the UE in the RRC idle mode or the RRC inactive mode, the UE can identify the first ID, the second ID, the RNTI, or the logical channel ID configured or allocated for the MBS of interest to the UE or to be received by the UE, and by using the identified ID, the UE can receive the MBS data through the MBS user data channel and receive the MBS by applying the method provided in the disclosure FIG. 1G or 1H.

[0372] In order to receive the MBS, the UE can transmit the first RRC message 1l-10, can receive the second RRC message 1l-15, can retransmit the message of the third RRC message 1l-20, can receive the fourth RRC message, can transmit the fifth RRC message, and can receive the MBS in the RRC connected mode. Alternatively, thereafter, the UE can receive the sixth RRC message 1l-45, and can receive the MBS in the RRC idle mode or the RRC inactive mode.

[0373] According to another method, in order to receive the MBS, the UE can transmit the first RRC message 1l-10, can receive the second RRC message 1l-15 (transition to the RRC connected mode), can retransmit the message of the third RRC message 1l-20, can receive the sixth RRC message 1l-45, and can transition to the RRC idle mode or the RRC inactive mode to receive the MBS in the RRC idle mode or the RRC inactive mode.

[0374] The first RRC message or the second RRC message can not be applied with the ciphering or the integrity protection. According to another method, in order to enhance security, the first RRC message or the second RRC message can not be applied with the ciphering or the integrity protection, and the first RRC message or the second RRC message can be applied with the ciphering or the integrity protection. According to another method, in order to further enhance security, the first RRC message or the second RRC message can be applied with the ciphering or the integrity protection, and the first RRC message or the second RRC message can be applied with the ciphering or the integrity protection. The third RRC message can be applied with the ciphering or the integrity protection. In addition, the fourth RRC message, the fifth RRC message, or the sixth RRC message can also be applied with the ciphering or the integrity protection.

[0375] FIG. 1M is a diagram of a fourth signaling procedure supporting MBS according to embodiments of the disclosure.

[0376] In the fourth signaling procedure supporting MBS according to the disclosure, the UE can identify the MBS of interest or broadcasted to the UE based on the system information, establish a connection with the network, and indicate the MBS of interest or the intention of the UE to receive the MBS to the base station (or network), receive the MBS-related configuration information from the base station (or network), and receive the MBS. In the third signaling procedure, the UE can remain in the RRC idle mode, the RRC connected mode, or the RRC inactive mode. According to another method, the UE can enter the RRC connected mode from the RRC idle mode or the RRC inactive mode, in order to indicate the MBS of interest or the intention of the UE to receive the MBS to the base station (or network), and receive the MBS configuration information from the base station (or network). Alternatively, after the UE receives the MBS configuration information, the UE can receive the MBS in the RRC connected mode, or can receive the MBS in the RRC idle mode or the RRC inactive mode.

[0377] Reference FIG. 1M , the UE 1m-01 can perform cell selection or reselection in the RRC idle mode or the RRC inactive mode, can select an appropriate cell, and can camp on the cell. Then, the UE 1m-01 can receive the system information 1m-05 from the gNB 1m-02 in the RRC idle mode, the RRC inactive mode, or the RRC connected mode, and can receive some configuration information of the MBS from the system information. The configuration information of the MBS can include one or more of the following pieces of configuration information. That is, in order to support the MBS, the network can transmit the system information including one or more of the following pieces of configuration information.

[0378] - Whether the MBS is supported.

[0379] - configuration information for a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) for the MBS.

[0380] - information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) for the MBS is transmitted.

[0381] - configuration information on an MBS supported by a current cell. For example, a list of MBSs or a first ID (e.g., TMGI) or a second ID (e.g., session identification) of each MBS can be configured or broadcast, and information on a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identification) or an RNTI of an MBS can be configured or broadcast for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information. The first ID can indicate a PLMN providing the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0382] A bearer can be configured as FIG. 1GThe configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in an RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0383] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0384] - information about an MBS-specific carrier or cell (Cell, SCell, or PCell) of an MBS (for example, a frequency, a time resource, or a cell ID).

[0385] - MBS-specific BWP information (for example, DL BWP information or UL BWP information) or BWP ID information of an MBS.

[0386] - indicator information configuring a header compression function or procedure for a bearer supporting an MBS (in the disclosure, a header compression procedure (for example, ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (for example, an indicator indicating whether to further use a header compression context)).

[0387] - In the above-described configuration information, the length of a PDCP sequence number or an RLC sequence number can also be configured, and according to another method, a default length of an RLC sequence number or a PDCP sequence number can be defined.

[0388] - In the above configuration information, an indicator indicating whether an RLC entity of a bearer supporting an MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0389] When the configuration information of the MBS in the camped cell is not broadcast via system information, the UE can transmit a message or an indicator requesting the system information of the MBS in the camped cell to the base station, the cell, or the network. When the base station or the network receives the message or the indicator, the base station or the network can broadcast or transmit the configuration information of the MBS by using the system information. By doing so, the base station can prevent the waste of transmission resources that can occur when the MBS-related system information is unnecessarily and continuously broadcast.

[0390] The UE receiving or identifying the MBS-related information via the system information, the UE identifying that the MBS the UE is interested in is being broadcast in the current cell via the system information, or the UE to request the MBS the UE is interested in to the network can perform a random access procedure and transmit a first RRC message (1m-10) to the network. The first RRC message can be a newly defined RRC message for the MBS, or can be defined as an RRCSetupRequest message, an RRCResumeRequest message, or a previous other RRC message. The UE can include in the first RRC message an indicator indicating that the UE wants to receive the MBS, an indicator indicating that the MBS is received to establish an RRC connection with the network, or a first ID, a second ID, a logical channel ID, an RNTI, or a bearer ID of the MBS the UE is interested in or the UE wants to receive. The UE can include in the first RRC message a bearer type (e.g., a unicast bearer or a multicast bearer) or a bearer structure applied, established, or used for the MBS, or a preferred bearer type (e.g., a unicast bearer or a multicast bearer) or a preferred bearer structure, or an indicator indicating in which RRC mode (an RRC connected mode, an RRC idle mode, or an RRC inactive mode) the UE wants to receive the MBS. Alternatively, the UE can transmit the first RRC message by including in the first RRC message an indicator for the MBS the UE is no longer interested in, the UE wants to stop receiving, or the UE has stopped receiving, or an indicator indicating a switch to another MBS. The indicators included in the first RRC message by the UE can be determined or indicated based on the system information received in 1m-05. In addition, the UE can report UE capability information for the MBS to the base station or the network through an additional RRC message. For example, when the base station transmits an RRC message requiring UE capability information to the UE, the UE, in response to the RRC message requiring UE capability information, can include configuration information about a function or configuration supported by the UE capability when the UE receives the MBS or configuration information about a function or configuration implemented in the UE, in a UE capability response RRC message, and can transmit the UE capability response RRC message to the base station or the network. When the UE previously configures a connection, when the UE stores a UE ID (e.g., a UE ID (5G-S-TMSI) allocated from a core network or a UE ID (short I-RNTI or I-RNTI) allocated from a base station for resuming an RRC connection) allocated from the network, or when the UE ID is indicated by an upper layer entity (e.g., an NAS entity or an RRC entity), the UE can transmit the first RRC message by including the UE ID in the first RRC message so that the network can distinguish or identify the UE. For example, the base station or the network can identify the UE based on the UE ID included in the first RRC message, can identify the UE by retrieving UE capability information from a core network, or can identify the UE by retrieving configuration information of the UE from a base station the UE previously connected to.When the UE receives system information, is to receive a service of interest, has a service of interest, or determines a system of interest, when the UE is in or enters a cell or domain in which MBS is supported in the system information, or when the MBS (or session) is configured or connected, the UE can configure a connection with the network and transmit a first RRC message.

[0391] In 1m-10, when the base station receives the first RRC message, the base station can identify the MBS of interest to the UE or to be received by the UE or UE capability information.

[0392] The base station or network can transmit a second RRC message 1m-15 to the UE in order to support or configure the MBS for the UE (1m-15). The second RRC message can be a newly defined RRC message for the MBS, or can be defined as an RRCRelease message, an RRCReconfiguration message, or a previous other RRC message.

[0393] The second RRC message can include configuration information for the MBS, MBS configuration information or bearer configuration information indicated by the UE in the first RRC message, or configuration information about unicast bearer, multicast bearer, or MBS bearer for receiving the MBS.

[0394] The second RRC message can be transmitted by including one or more of the following segment configuration information supporting the MBS.

[0395] - Whether the MBS is supported.

[0396] - Configuration information about a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) for the MBS.

[0397] - Information about a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) is transmitted.

[0398] - Configuration information about MBS supported by the current cell. For example, a list of MBSs or a first ID (e.g., TMGI) or a second ID (e.g., session identification) of each MBS can be configured or broadcast, and information about a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID of each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identification) or an RNTI of each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information can be configured or broadcast. The first ID can indicate a PLMN that provides the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information about a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0399] The bearer can be configured as FIG. 1G the bearer structure provided in the above, to receive the MBS. In addition, the configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in the RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0400] - Indicator configuration information indicating whether a bearer or a bearer ID that supports (transmits or receives) the MBS is a unicast bearer or a multicast bearer.

[0401] - Information on an MBS dedicated carrier or cell (Cell, SCell, or PCell) for MBS (e.g., frequency, time resource, or cell ID).

[0402] - MBS dedicated BWP information (e.g., DL BWP information or UL BWP information) or BWP ID information for MBS.

[0403] - Information on an indicator configuring a header compression function or procedure for a bearer supporting MBS (In the disclosure, a header compression procedure (e.g., ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (e.g., an indicator indicating whether to further use a header compression context)).

[0404] - In the above configuration information, the length of the PDCP sequence number or the RLC sequence number can also be configured, and according to another method, the default length of the RLC sequence number or the PDCP sequence number can be defined.

[0405] - In the above configuration information, an indicator indicating whether the RLC entity of the bearer supporting MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0406] The UE receiving the second RRC message can store or apply the MBS-related configuration information, can search for or determine an MBS in which the UE is interested or the UE wants to receive, and can receive MBS data (MBS control data or MBS user data) through a transmission resource through which an MBS control data channel or an MBS user data channel for the MBS in which the UE is interested is transmitted. When the UE receives system information, is to receive a service in which the UE is interested, has a service in which the UE is interested, or determines a system in which the UE is interested, when the UE is in or enters a cell or a domain in which MBS is supported in the system information, when an MBS (or a session) is configured or connected, or when configuration information or bearer configuration information of the MBS is received or broadcast via system information, an RRC message (RRCSetup, RRCResume, RRCReconfiguration, RRCRelease, or a newly defined new RRC message), or a control message of an MBS channel (e.g., transmitted from an MBS control data channel), the UE can configure a unicast bearer, a multicast bearer, or an MBS bearer in order to receive an MBS having a provided bearer structure.

[0407] When the UE receives the second RRC message, the UE can apply the configuration information included in the second RRC message, and in response, can transmit a third RRC message (e.g., RRCSetupComplete or RRCResumecomplete) to the base station or the network (1m-20).

[0408] The UE can receive the MBS configuration data by receiving MBS data (e.g., MBS control data) with respect to an MBCCH or a transmission resource of an MBS of interest to the UE.

[0409] When the UE receives the MBS configuration information, in order to receive an MBS of interest to the UE or to be received by the UE, the UE can identify a first ID, a second ID, an RNTI, or a logical channel ID configured or allocated for the MBS of interest to the UE or to be received by the UE, and by using the identified ID, can receive MBS data through an MBS user data channel and receive the MBS (1m-25) by applying the method provided in 1H of the disclosure. FIG. 1G

[0410] The base station can transmit a fourth RRC message (e.g., RRCReconfiguration 1m-30) to the UE to support an MBS, to configure or reconfigure a bearer through which the UE receives an MBS, or to configure or reconfigure MBS-related configuration information, based on a preference reported by the UE, an indicator indicated by the UE, or an embodiment of the base station. For example, the fourth RRC message can include configuration information for changing a bearer type (e.g., an indicator to convert a unicast bearer into a multicast bearer, an indicator to convert a multicast bearer into a unicast bearer, or bearer configuration information corresponding thereto), or logical channel ID information, RNTI information, or first ID or second ID information of an MBS to be changed or updated for each MBS.

[0411] After the UE receives the fourth RRC message and stores or applies the MBS-related configuration information, the UE can configure a fifth RRC message (e.g., RRCReconfigurationComplete 1m-35) indicating successful reconfiguration and transmit the fifth RRC message to the base station.

[0412] The UE can receive the MBS configuration data by receiving MBS data (e.g., MBS control data) with respect to an MBCCH or a transmission resource of an MBS of interest to the UE.

[0413] When the UE receives the MBS configuration information, in order to receive an MBS of interest to the UE or to be received by the UE, the UE can identify a first ID, a second ID, an RNTI, or a logical channel ID configured or allocated for the MBS of interest to the UE or to be received by the UE, and by using the identified ID, can receive MBS data through an MBS user data channel and receive the MBS (1m-40) by applying the method provided in 1H of the disclosure. FIG. 1G

[0414] ​​When the base station is to transition the UE to the RRC inactive mode or the RRC idle mode (e.g., according to the embodiment of the base station, the request of the UE, or the indication of the UE), the base station can configure a sixth RRC message (e.g., RRCRelease 1m-45) and transmit the sixth RRC message to the UE to transition the UE to the RRC idle mode or the RRC inactive mode. The sixth RRC message 1m-45 can include the following information or some of the following information, so that the UE can continuously receive the MBS (1m-50) even in the RRC idle mode or the RRC inactive mode.

[0415] - Whether the MBS is supported.

[0416] - Configuration information on a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, MBTCH, or DL-SCH) for the MBS.

[0417] - Information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which a physical channel or a DL or UL transport channel (e.g., MBCH, MBCCH, or MBTCH) for the MBS is transmitted.

[0418] - Configuration information on the MBS supported by the current cell. For example, a list of MBSs or a first ID (e.g., TMGI) or a second ID (e.g., session identification) for each MBS can be configured or broadcast, and information on a logical channel ID, a bearer ID, or an RNTI corresponding to the first ID or the second ID for each MBS can be configured or broadcast. According to another method, a first ID (e.g., TMGI) or a second ID (e.g., session identification) or an RNTI for each bearer (or bearer ID), each logical channel, each piece of RLC configuration information, or each piece of PDCP configuration information can be configured or broadcast. The first ID can indicate a PLMN providing the MBS, a type of the MBS, or a session. The second ID can indicate a more detailed session or a type of the MBS. In addition, the configuration information for the MBS can include information on a transmission resource (frequency, time resource, transmission period, BWP (or BWP ID), bandwidth, dedicated frequency (frequency information or SCell ID), subcarrier spacing, subframe number, ID indicating a transmission mode, etc.) through which each MBS is supported, broadcast, or transmitted.

[0419] The bearer can be configured to FIG. 1GThe configuration information can include indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, indicator configuration information indicating whether to use RLC reordering, information about a transmission resource for transmitting HARQ ACK or NACK, indicator configuration information indicating whether to use RLC in-sequence delivery, configuration information about an RLC reordering timer value, or indicator configuration information for whether to use PDCP out-of-sequence delivery. The indicator configuration information indicating HARQ reordering, HARQ retransmission, or whether to use HARQ ACK or NACK, the indicator configuration information indicating whether to use RLC reordering, the indicator configuration information indicating whether to use RLC in-sequence delivery, the configuration information about an RLC reordering timer value, configuration information for an RLC mode (TM, UM, or AM), configuration information for whether to use a function of splitting data in an RLC entity, or indicator configuration information for whether to use PDCP out-of-sequence delivery can be configured for each MBS or each bearer. According to another method, the configuration information can be defined as default configuration information, and in the absence of the configuration information, the MBS bearer can be configured, and the UE has some of the described functions by default via the MBS bearer.

[0420] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0421] - indicator configuration information indicating whether a bearer or a bearer ID supporting (transmitting or receiving) an MBS is a unicast bearer or a multicast bearer.

[0422] - an indicator or configuration information indicating a transition to an RRC idle mode, an RRC inactive mode, or an RRC connected mode.

[0423] - MBS configuration information or bearer configuration information provided for receiving an MBS in an RRC idle mode.

[0424] - MBS configuration information or bearer configuration information provided for receiving an MBS in an RRC inactive mode.

[0425] - information about an MBS-specific carrier or cell (Cell, SCell, or PCell) of an MBS (for example, a frequency, a time resource, or a cell ID).

[0426] - MBS-specific BWP information (for example, DL BWP information or UL BWP information) or BWP ID information of an MBS.

[0427] - information on an indicator configuring a header compression function or procedure for a bearer supporting MBS (in the disclosure, a header compression procedure (e.g., ROHC, EHC, or a data compression procedure can be configured and supported), or configuration information of a header compression procedure or a data compression procedure (e.g., an indicator indicating whether to further use a header compression context).

[0428] - In the above configuration information, the length of a PDCP sequence number or an RLC sequence number can also be configured, and according to another method, a default length of an RLC sequence number or a PDCP sequence number can be defined.

[0429] - In the above configuration information, an indicator indicating whether an RLC entity of a bearer supporting MBS supports or allows one-way communication or supports or allows two-way communication can also be configured.

[0430] When the UE receives the MBS configuration information, in order to receive an MBS in which the UE is interested or which the UE is to receive, the UE can identify a first ID, a second ID, an RNTI, or a logical channel ID configured or allocated for the MBS in which the UE is interested or which the UE is to receive, and by using the identified ID, can receive MBS data through an MBS user data channel and receive the MBS by applying the method provided in the disclosure FIG. 1G or 1H.

[0431] In order to receive the MBS, the UE can transmit the first RRC message 1m-10, can receive the second RRC message 1m-15, can retransmit the message of the third RRC message 1m-20, can receive the fourth RRC message, can transmit the fifth RRC message, and can receive the MBS in an RRC connected mode. Alternatively, thereafter, the UE can receive the sixth RRC message 1m-45, and can receive the MBS in an RRC idle mode or an RRC inactive mode.

[0432] According to another method, in order to receive the MBS, the UE can transmit the first RRC message 1m-10, can receive the second RRC message 1m-15 (transition to an RRC connected mode), can retransmit the message of the third RRC message 1m-20, can receive the sixth RRC message 1m-45, and can transition to an RRC idle mode or an RRC inactive mode to receive the MBS in the RRC idle mode or the RRC inactive mode.

[0433] The encryption processing or integrity protection processing can not be applied to the first RRC message or the second RRC message. According to another method, in order to enhance security, the encryption processing or integrity protection processing can not be applied to the first RRC message or the second RRC message, and the encryption processing or integrity protection processing can be applied to the first RRC message or the second RRC message. According to another method, in order to further enhance security, the encryption processing or integrity protection processing can be applied to the first RRC message or the second RRC message, and the encryption processing or integrity protection processing can be applied to the first RRC message or the second RRC message. The encryption processing or integrity protection processing can be applied to the third RRC message. In addition, the encryption processing or integrity protection processing can also be applied to the fourth RRC message, the fifth RRC message, or the sixth RRC message.

[0434] In the next-generation mobile communication system according to the disclosure, the first signaling procedure, the second signaling procedure, the third signaling procedure, or the fourth signaling procedure provided according to the disclosure can be supported.

[0435] FIG. 1N is a diagram of a case in which general data and MBS data collide or overlap with each other when a UE receives a general data service and an MBS in an RRC connected mode according to an embodiment of the disclosure.

[0436] Referring to FIG. 1N , the UE in the RRC connected mode receiving the general data service or the MBS can receive first scheduling information 1n-05 for the general data service and second scheduling information 1n-10 for the MBS data.

[0437] The first scheduling information 1n-05 can indicate time resources or frequency resources through which the general data of the DL is transmitted by using the DCI of the PDCCH scrambled by the first RNTI (for example, the C-RNTI, which is an RNTI used to schedule the general data). According to another method, the first scheduling information indication can be indicated as a configuration for time resources or frequency resources for transmitting the general data of the DL by using the RRC message. According to another method, the first scheduling information indication can be indicated as a configuration for periodic time resources or frequency resources for transmitting the general data of the DL by using the RRC message, or the first scheduling information can be indicated via activation or deactivation of the periodic time resources or frequency resources by using the DCI of the PDCCH.

[0438] The second scheduling information can indicate time resources or frequency resources through which the DL MBS data is transmitted by using the DCI of the PDCCH scrambled by the second RNTI (e.g., MBS-RNTI, which is an RNTI for scheduling MBS data or an RNTI for each MBS). According to another method, the second scheduling information can be indicated as time resources or frequency resources configured for transmitting the DL MBS data by using system information, an RRC message, a control channel, or a control message of the MBS. According to another method, the second scheduling information can be indicated as periodic time resources or frequency resources configured for transmitting the DL MBS data by using system information, an RRC message, a control channel, or a control message of the MBS, or the second scheduling information can be indicated via activation or deactivation of the periodic time resources or frequency resources by using the DCI of the PDCCH.

[0439] When the UE receives the first scheduling information and the second scheduling information (1n-15), and when the time resources or frequency resources of the DL indicated by the first scheduling information or the second scheduling information are the same as each other, overlap with each other, or collide with each other, the UE can need a method of processing the first scheduling information and the second scheduling information.

[0440] Accordingly, next, according to the disclosure, there is provided a method of processing first scheduling information and second scheduling information when the UE receives the first scheduling information and the second scheduling information (1n-15) and when time resources or frequency resources of a DL indicated by the first scheduling information or the second scheduling information are the same as each other, overlap with each other, or collide with each other, as described above.

[0441] - A first method: When the time resources or frequency resources indicated by the first scheduling information and the second scheduling information are the same as each other, overlap with each other, or collide with each other, the UE can receive general data via the time resources or frequency resources according to the first scheduling information. In addition, the UE can not receive the MBS data indicated by the second scheduling information, can ignore the MBS data indicated by the second scheduling information, or can not consider the second scheduling information. According to another method, when a transmission resource (e.g., PUCCH) of a HARQ ACK or NACK through which the DL MBS data indicated by the second scheduling information is transmitted is configured, or it is configured to transmit the HARQ ACK or NACK, the UE can indicate a NACK indicating that the MBS is not successfully received, and can request retransmission, and can subsequently receive the un-received DL MBS data through the retransmission.

[0442] - Second method: When the time resources or the frequency resources indicated by the first scheduling information and the second scheduling information are the same as each other, overlap with each other, or collide with each other, the UE can receive the MBS data via the time resources or the frequency resources according to the second scheduling information. In addition, the UE can not receive the general data indicated by the first scheduling information, can ignore the general data indicated by the first scheduling information, or can not consider the first scheduling information. However, the UE can indicate NACK (HARQ ACK or NACK for the general data of the DL indicated by the first scheduling information via a transmission resource (e.g., PUCCH) with respect to the general data of the DL indicated by the first scheduling information) representing unsuccessful reception, through the transmission resource, to request retransmission, and can subsequently receive the general data of the DL that was not received through the retransmission.

[0443] - Third method: When the UE is capable of simultaneously receiving different data via transmission resources with the same time resources or the same frequency resources according to the UE capability, the UE can receive the general data and the MBS data indicated by the first scheduling information and the second scheduling information, respectively. For example, when the UE includes multiple antennas or the UE satisfies a relatively more complex requirement according to the UE capability, the third method can be applied.

[0444] - Fourth method: Whether the UE is to perform the first method, the second method, or the third method can be configured or indicated by the base station by using an RRC message or system information.

[0445] - Fifth method: The base station can transmit the general data and the MBS data that are different from each other by multiplexing the different data as one type of data (e.g., MAC PDU) via transmission resources with the same time resources or the same frequency resources. That is, the UE can receive one type of data (e.g., MAC PDU) via transmission resources with the same time resources or the same frequency resources, and the one type of data can include the general data and the MBS data that are multiplexed. In one type of data, each piece of the general data can be identified based on a logical channel ID (e.g., an ID included in a MAC header) corresponding to each piece of the general data, and each piece of the MBS data can be identified based on a logical channel ID (e.g., an ID included in a MAC header) corresponding to each piece of the MBS data. When the UE receives one type of data and performs data processing thereon, the UE can receive (or demultiplex) data corresponding to a logical channel ID configured in the UE, and can transmit the data to an upper layer entity (e.g., an RLC entity or an upper layer entity) corresponding to the logical channel ID, and can discard data corresponding to a logical channel ID that is not configured in the UE.

[0446] FIG. 1O is a diagram of a signaling procedure for efficiently supporting MBS according to an embodiment of the disclosure.

[0447] For example, to support MBS, signaling procedures 1o-05 are provided in which the UE receiving MBS data sends feedback to the base station, signaling procedure 1o-10 is provided in which the UE receiving MBS data receives MBS-related control messages from the base station, or signaling procedures 1o-20 and 1o-25 are provided in which the base station sends MBS-related control messages to the UE and the UE sends a response to them.

[0448] refer to FIG. 1O ,exist FIG. 1O In signaling procedure 1o-05, the UE receiving MBS data can send feedback or indication information about the MBS to the network or base station. For example, when a predetermined event occurs, when there is a service the UE is interested in (or wants to receive), when the service the UE is interested in (or wants to receive) changes, when the UE wants to stop receiving the service the UE is interested in (or wants to receive), when the UE suspends MBS, or when the UE changes its method of receiving MBS or changes its RRC mode or bearer, the UE can send feedback or indication information about the MBS to the network or base station (1o-05). According to another method, when there is a request from the network (1o-03), the feedback or indication information can be sent by the UE. The information sent by the UE to the base station relative to the MBS may include some of the following:

[0449] - Information about the MBS that the UE is interested in or wants to receive (e.g., the first ID, second ID, logical channel ID, RNTI, or bearer ID for the MBS).

[0450] - When the UE receives or configures an MBS, the RRC connection state (e.g., RRC idle mode, RRC connected mode, or RRC inactive mode) is selected by the UE.

[0451] *451 - When the UE receives or configures an MBS, the bearer structure or configuration information that the UE preferentially selects (e.g., unicast bearer, multicast bearer, ...) FIG. 1G The description includes the preferred structure within the bearer architecture, and the UE's preferred configuration of functions, etc.

[0452] - When the UE receives or configures an MBS, the service type that the UE preferentially selects (e.g., unicast service (dedicated service) or multicast service (multicast, broadcast, or public service)).

[0453] - an indicator indicating the intention of the UE receiving the MBS to no longer receive the MBS, an indicator indicating the intention of the UE to stop receiving the MBS, an indicator indicating the intention of the UE to further receive the MBS, an indicator requesting the MBS to be changed to another MBS (or a first ID, a second ID, a logical channel ID, a bearer ID, or an RNTI for another MBS), or an indicator indicating that the UE is interested in the MBS.

[0454] - an indicator indicating good or bad with respect to the reception quality of the MBS from the perspective of the UE.

[0455] - an indicator indicating successful reception or unsuccessful reception of the MBS, for example, HARQ ACK or NACK feedback.

[0456] When the UE transmits the above information for the MBS to the base station, the UE can transmit the information only in an RRC connected mode. For example, when the above information is requested from the base station, or when the UE needs to transmit the above information, the UE in the RRC connected mode can configure and transmit the above information by using an RRC message, MAC control information, RLC control information, or PDCP control information through an SRB, a DRB, or an MBS bearer (a unicast bearer or a multicast bearer) configured to the UE in the RRC connected mode. According to another method, when the above information is requested from the base station or the UE needs to transmit the above information, the UE in an RRC idle mode or an RRC inactive mode can configure a connection with the network (triggering an RRC connection procedure or an RRC connection resume procedure), can convert the RRC idle mode or the RRC inactive mode to the RRC connected mode, and can configure and transmit the above information by using an RRC message, MAC control information, RLC control information, or PDCP control information through an SRB, a DRB, or an MBS bearer (a unicast bearer or a multicast bearer) configured to the UE in the RRC connected mode. According to another method, when the UE transmits the above information for the MBS to the base station, the UE can transmit feedback or indication information of the UE in an RRC connected mode, an RRC inactive mode, or an RRC idle mode through a transmission resource indicated in system information, a transmission resource configured using an RRC message, or a transmission resource indicated by a PDCCH including an RNTI indicating the MBS. When the UE transmits the feedback as described above, the base station can more efficiently manage resources of the MBS.

[0457] Reference FIG. 1O With respect to 1o-10, the base station can transmit control information for the MBS to the UE receiving the MBS. The control information for the MBS can be transmitted through a channel, a transmission resource, an RRC message, MAC control information, RLC control information, or PDCP control information of the MBS (1o-10).

[0458] The control information for the MBS can include some of the following information.

[0459] - an indicator indicating a request to suspend MBS reception.

[0460] - an indicator indicating that the base station is to suspend the MBS or an indicator indicating that the UE is to stop receiving the MBS.

[0461] - an ID of the MBS to be suspended or to be stopped in reception thereof. For example, a first ID, a second ID, a logical channel ID, an RNTI, or a bearer ID corresponding to the MBS can be included to more specifically indicate to the UE which MBS is to be suspended or which MBS the UE is to stop receiving. According to another method, the control information can be transmitted and indicated by a PDCCH scrambled by an RNTI corresponding to the MBS. According to another method, the first ID, the logical channel ID, the RNTI, or the bearer ID can be included in a list and transmitted in support of multiple MBSs.

[0462] - To more specifically indicate which MBS is to be suspended or which MBS the UE is to stop receiving, a first ID value or a second ID value indicating an MBS configured in an MBS list configured via system information or an RRC message can be mapped in ascending order with a natural number value, and the natural number value can be input or mapped to a bitmap so that the bitmap can indicate the MBS.

[0463] - A time point at which to start stopping reception of the MBS or a time point at which to suspend the MBS can be indicated in a time unit (subframe, slot, or symbol). For example, it can be indicated that the time unit is the nth in a period in which the MBS is transmitted. According to another method, it can be indicated that it is the nth after the time unit from a time point at which the control information is received.

[0464] When the base station transmits control information for the MBS to the UE, the base station can transmit the control information to the UE in an RRC inactive mode, an RRC idle mode, or an RRC connected mode. For example, the base station can configure and transmit information to the UE in the RRC inactive mode, the RRC idle mode, or the RRC connected mode by using an RRC message, MAC control information, RLC control information, or PDCP control information through an SRB, a DRB, or an MBS bearer (unicast bearer or multicast bearer). According to another method, the base station can transmit the control information to the UE in the RRC connected mode, the RRC inactive mode, or the RRC idle mode through a transmission resource indicated in system information, a transmission resource configured in an RRC message, or a transmission resource indicated by a PDCCH including an RNTI indicating the MBS.

[0465] When the UE receives the control information from the base station (1o-10), the UE can transmit corresponding feedback to the base station as FIG. 1OThe described feedback or instruction information (1o-15).

[0466] When the UE receives control information from the base station (1o-10), and when the UE still has MBS of interest or when the UE still wants to receive MBS, the UE can re-receive such information. FIG. 1K , 1L The control information related to MBS (e.g., system information, RRC messages, or MBS control messages) described in 1M or 1N, or the execution (or triggering) of an RRC connection procedure or an RRC connection recovery procedure to receive or request configuration information from the base station for re-receiving MBS, can re-receive MBS configuration information, can reconfigure MBS configuration information, and can continuously receive MBS.

[0467] According to another method, when the UE receives control information from the base station (1o-10), if the UE is not in RRC connected mode and is in RRC idle mode or RRC inactive mode, or if the UE still has MBS of interest to the UE, or if the UE still wants to receive MBS, the UE can re-receive such information. FIG. 1K , 1L The control information related to MBS (e.g., system information, RRC messages, or MBS control messages) described in 1M or 1N, or the execution (or triggering) of the RRC connection process or RRC connection recovery process, can receive or request configuration information from the base station for re-receiving MBS, can re-receive MBS configuration information, can reconfigure MBS configuration information, and can continuously receive MBS.

[0468] As mentioned above, by sending control information to the UE, the base station can manage the resources of the MBS relatively more efficiently.

[0469] refer to FIG. 1O In 1o-20 and 1o-25, to identify how many UEs have received MBS, the base station can configure and send a message requesting a response to indicate whether a UE receiving MBS data has received MBS or to count the number of UEs receiving MBS. A UE receiving the message requesting a response to indicate whether MBS has been received or to count the number of UEs receiving MBS can configure and send the response message to the base station (1o-25).

[0470] The request configured by the base station for a message of a response for identifying whether the MBS is received or for the number of UEs receiving the MBS can be transmitted to or received by the UE in the RRC idle mode, the RRC inactive mode, or the RRC connected mode. Further, the UE receiving the request message can configure a response message for the request message when the UE is in the RRC idle mode, the RRC inactive mode, or the RRC connected mode, and can transmit the response message through the SRB, the DRB, or the MBS bearer (unicast bearer or multicast bearer) configured to the UE, by using the RRC message, the MAC control information, the RLC control information, or the PDCP control information. In addition, the UE can transmit the response message through the transmission resource indicated in the system information, the transmission resource configured in the RRC message, or the transmission resource indicated by the PDCCH including the RNTI indicating the MBS.

[0471] According to another method, the request configured by the base station for a message of a response for identifying whether the MBS is received or for the number of UEs receiving the MBS can be transmitted to or received by the UE in the RRC idle mode, the RRC inactive mode, or the RRC connected mode. Further, the UE in the RRC connected mode among the UEs receiving the request message can configure a response message for the request message, and can transmit the response message through the SRB, the DRB, or the MBS bearer (unicast bearer or multicast bearer), by using the RRC message, the MAC control information, the RLC control information, or the PDCP control information. In addition, the UE can transmit the response message through the transmission resource indicated in the system information, the transmission resource configured in the RRC message, or the transmission resource indicated by the PDCCH including the RNTI indicating the MBS. According to another method, the UE in the RRC idle mode or the RRC inactive mode among the UEs receiving the request message can perform an RRC connection procedure or an RRC connection resume procedure to convert the RRC idle mode or the RRC inactive mode to the RRC connected mode, and can transmit the response message through the SRB, the DRB, or the MBS bearer (unicast bearer or multicast bearer) configured to the UE, by using the RRC message, the MAC control information, the RLC control information, or the PDCP control information. Alternatively, the UE can transmit the response message through the transmission resource indicated in the system information, the transmission resource configured in the RRC message, or the transmission resource indicated by the PDCCH including the RNTI indicating the MBS.

[0472] FIG. 1P FIG. 1 is a diagram illustrating a method of indicating each of a plurality of MBSs according to an embodiment of the disclosure.

[0473] Reference FIG. 1P As shown in 1p-05, each MBS can have a mapping relationship with a first ID, a second ID, a logical channel ID, an RNTI, or a bearer ID of the MBS, or each ID can be allocated to each MBS.

[0474] Based on the scheme of 1p-05, each MBS can be identified, and a specific MBS can be identified and indicated by an ID. However, the ID is long, and thus, in terms of the overhead problem, indicating each MBS via the first ID, the second ID, the logical channel ID, the RNTI, or the bearer ID can not be an efficient method.

[0475] In the disclosure, in a system information, an RRC message, or an MBS control message, a list for supported MBSs or a list for configured MBSs can be broadcast, agreed, or configured, and an integer value can be allocated or mapped to each MBS configured in the list for MBSs, as shown in 1p-10. According to another method, an integer value can be mapped or allocated in ascending (or descending) order for each ID value of a corresponding MBS included in the list for MBSs. In addition, when a specific MBS is indicated, the MBS can be indicated by the integer value, and thus, the overhead can be reduced. For example, when a plurality of MBSs is indicated, respective integer values for the plurality of MBSs can be included in the list to indicate the plurality of MBSs.

[0476] According to another method, a list for supported MBSs or a list for configured MBSs can be broadcast, agreed, or configured in a system information, an RRC message, or an MBS control message, and each bit of a bitmap can be allocated or mapped to each MBS configured in the list for MBSs, as shown in 1p-15. According to another method, each bit of the bitmap can be mapped or allocated in ascending (or descending) order for each ID value of a corresponding MBS included in the list for MBSs. In addition, when a specific MBS is indicated, the MBS can be indicated by each bit of the bitmap (for example, each MBS can be indicated by a value of 1 or 0), and thus, the overhead can be reduced. For example, when a plurality of MBSs is indicated, respective bit values for the plurality of MBSs can be configured in the bitmap to indicate the plurality of MBSs.

[0477] FIG. 1P The method of indicating each MBS in 1p-05 can be applied to various signaling procedures according to the disclosure based on application or extension.

[0478] For example, when a list for supported MBSs or a list for configured MBSs is broadcast, agreed, or configured in a system information, an RRC message, or an MBS control message, an integer value can be allocated or mapped to each MBS configured in the list for MBSs, as shown in 1p-10. FIG. 1OIn 1o-20 and 1o-25, the base station configures and transmits a message requesting a response for identifying whether the UE receiving the MBS data receives the MBS or for counting the number of UEs receiving the MBS, in order to identify how many UEs receive the MBS, and the UE receiving the message requesting the response configures a response message and transmits the response message to the base station, and the following method can be applied.

[0479] In detail, the message requesting a response for identifying whether the UE receives the MBS or for counting the number of UEs receiving the MBS and the response message in response thereto can be configured or generated by one of the following methods.

[0480] The first method is as follows. FIG. 1PAccording to another method, when the base station configures the request message, by applying the method 1p-10, an integer value can be allocated or mapped to each MBS for a list of MBSs configured by using the system information, the RRC message, or the MBS control message. For example, the integer value can be mapped or allocated in ascending (or descending) order for each ID value for a corresponding MBS included in the list for the MBSs. Further, the mapped or allocated integer value can be included in the request message or the list so that how many UEs receive the MBSs can be indicated. According to another method, by applying the method 1p-15, when the request message is configured, the base station can allocate or map each bit of a bitmap to each MBS for a list of MBSs configured by using the system information, the RRC message, or the MBS control message. For example, each bit of the bitmap can be mapped or allocated in ascending (or descending) order for each ID value for a corresponding MBS included in the list for the MBSs. Further, when how many UEs receive the MBSs is to be identified via the request message, the MBSs can be indicated by each bit of the bitmap (for example, each MBS can be indicated by a value of 1 or 0) to reduce overhead. Further, when a plurality of MBSs is indicated, a corresponding bit value for the plurality of MBSs can be configured in the bitmap to indicate the plurality of MBSs. The UE receiving a corresponding MBS included in the request message can configure the response message by including an indication for whether the UE is interested in or receives the MBS in the response message so as to respond to the request. Since each MBS can have a mapping relationship with a first ID, a second ID, a logical channel ID, an RNTI, or a bearer ID of the MBS in a list for MBSs included in the request message or in a list of MBSs configured by using the system information, the RRC message, or the MBS control message, when the UE configures the response message, the UE can configure the IDs corresponding to the MBSs in which the UE is interested or the UE is to receive as a list by applying the method 1p-05, and can transmit the response message to the base station by including the list in the response message.When the UE configures the response message, the UE can assign or map an integer value to each MBS for a list of MBSs included in the request message or for a list of MBSs configured by using system information, an RRC message, or an MBS control message by applying the method of 1p-10. For example, the integer value can be mapped or assigned in an ascending (or descending) order for each ID value for a corresponding MBS included in the list for MBSs. Further, when the UE indicates MBSs in which the UE is interested or the UE wants to receive through the response message, the UE can include the mapped or assigned integer value in the response message or in the list so that the UE can indicate MBSs in which the UE is interested or the UE wants to receive to the base station. Accordingly, overhead can be reduced. Further, when a plurality of MBSs is indicated, corresponding integer values for the plurality of MBSs can be included in the response message or in the list to indicate the plurality of MBSs. According to another method, when the UE configures the response message by applying the method of 1p-15, the UE can assign or map each bit of a bitmap to each MBS for a list of MBSs included in the request message or for a list of MBSs configured by using system information, an RRC message, or an MBS control message. For example, each bit of the bitmap can be mapped or assigned in an ascending (or descending) order for each ID value for a corresponding MBS included in the list for MBSs. Further, when MBSs in which the UE is interested or the UE wants to receive are indicated in the response message, the MBSs can be indicated by each bit of the bitmap (e.g., each MBS can be indicated by a value of 1 or 0), and thus, overhead can be reduced. For example, when a plurality of MBSs is indicated, corresponding bit values for the plurality of MBSs can be configured in the bitmap to indicate the plurality of MBSs.

[0481] Second method: The base station can configure a request message requesting the UE to transmit a response message by configuring a response message for the MBS in which the UE is interested or the UE is to receive, and can transmit the request message to the UE. The request message can be transmitted to the UE receiving the MBS, or the UE receiving the MBS can receive the request message, and the request message can include an indicator indicating a request to configure a response message for whether the UE is interested in the MBS or the UE receives the MBS. The UE receiving the corresponding MBS included in the request message can configure the response message by including an indication for whether the UE is interested in the MBS or receives the MBS in the response message, thereby responding to the request. When the UE configures the response message, since each MBS can have a mapping relationship with the first ID, the second ID, the logical channel ID, the RNTI, or the bearer ID of the MBS in the list of the MBS configured by using the system information, the RRC message, or the MBS control message, the UE can configure the ID corresponding to the MBS in which the UE is interested or the UE is to receive as a list by applying the method of 1p-05, and can transmit the response message to the base station by including the list in the response message. According to another method, when the UE configures the response message, the UE can assign or map an integer value to each MBS in the list of the MBS configured by using the system information, the RRC message, or the MBS control message by applying the method of 1p-10. For example, the integer value can be mapped or assigned in ascending (or descending) order for each ID value for the corresponding MBS included in the list for the MBS. In addition, when the UE indicates the MBS in which the UE is interested or the UE is to receive through the response message, the UE can include the mapped or assigned integer value in the response message or in the list so that the UE can indicate the MBS in which the UE is interested or the UE is to receive to the base station. Accordingly, the overhead can be reduced. In addition, when a plurality of MBSs are indicated, the corresponding integer values for the plurality of MBSs can be included in the response message or in the list to indicate the plurality of MBSs. According to another method, by applying the method of 1p-15, when the UE configures the response message, the UE can assign or map each bit of a bitmap to each MBS in the list of the MBS configured by using the system information, the RRC message, or the MBS control message. For example, each bit of the bitmap can be mapped or assigned in ascending (or descending) order for each ID value for the corresponding MBS included in the list for the MBS. In addition, when the UE indicates the MBS in which the UE is interested or the UE is to receive in the response message, the UE can indicate the MBS by using each bit of the bitmap (for example, by using the value of 1 or 0 to indicate each MBS), and accordingly, the overhead can be reduced. For example, when a plurality of MBSs are indicated, the corresponding bit values for the plurality of MBSs can be configured in the bitmap to indicate the plurality of MBSs.

[0482] According to the present disclosure, in FIG. 1PMethods 1p-05, 1p-10, and 1p-15 indicating MBSs can be extended to be applied when indicating MBSs of interest or configuring configuration information of MBSs. For example, the method of indicating each MBS in FIG. 1P may be applied based on the extension to the method provided in FIG. 1J , 1K , 1L, 1M, or 1O.

[0483] The system information or configuration information configured in the RRC message according to the disclosure can include first discontinuous reception (DRX) configuration information (e.g., a period, a duration length (on duration), an offset, etc.) of a general data service. Accordingly, based on the first DRX configuration information of the general data service, the UE can monitor the PDCCH for a certain duration, or can not monitor the PDCCH for a certain duration to save power of the UE.

[0484] The system information or configuration information for MBS (configuration information of MBS is configured by using an RRC message or MBS control data) according to the disclosure can include second discontinuous reception (DRX) configuration information (e.g., a period, a duration length (on duration), an offset, etc.) of MBS. Accordingly, based on the second DRX configuration information of MBS, the UE can monitor the PDCCH for a certain duration, or can not monitor the PDCCH for a certain duration to save power of the UE.

[0485] The base station can configure the UE with the first DRX configuration information of the general data service or the second DRX configuration information of MBS, and when the UE is configured with the first DRX configuration information or the second DRX configuration information, the UE can operate the first DRX and the second DRX, respectively, and can transmit or receive data according to the first DRX or the second DRX, respectively, which is operated. For example, when the UE receives or transmits general data, the UE can operate the first DRX based on the first DRX configuration information, and can read or can not read the PDCCH to save power. In addition, when the UE receives or transmits MBS data, the UE can operate the second DRX based on the second DRX configuration information, and can read or can not read the PDCCH to save power.

[0486] FIG. 1Q is a diagram of a method of retransmitting MBS data according to an embodiment of the disclosure.

[0487] Referring to FIG. 1Q , as described above (e.g., in FIG. 1G , 1KWhen HARQ reordering, RLC reordering, HARQ ACK or NACK transmission, HARQ process, or HARQ retransmission is configured for an MBS or an MBS-supporting bearer by using system information, an RRC message, or an MBS control message, and when a UE does not successfully receive MBS data through a transmission resource indicated by a PDCCH (e.g., a PDCCH scrambled by an MBS RNTI) or a periodically configured transmission resource for an MBS (i.e., a transmission resource for an MBS configured in system information or an RRC message, which includes a time resource, a frequency resource, a period, an offset, or additional DRX configuration information (a period, an on-duration time, a duration (length) to read a PDCCH 1q-05 and 1q-10, or an offset) for an MBS), the UE can indicate a NACK through a transmission resource (e.g., a PUCCH) indicated by a PDCCH or using a transmission resource configured by system information, an RRC message, or an MBS control message. According to another method, when a UE successfully receives MBS data through a transmission resource indicated by a PDCCH (e.g., a PDCCH scrambled by an MBS RNTI) or a periodically configured transmission resource for an MBS, the UE can indicate an ACK.

[0488] According to another method, when a UE does not successfully receive MBS data through a transmission resource indicated by a PDCCH (e.g., a PDCCH scrambled by an MBS RNTI) or a periodically configured transmission resource, the UE can include an indicator or a UE ID indicating the UE in MAC control information, RLC control information, or PDCP control information, and can indicate to a base station which one of the UEs did not successfully receive MBS data. According to another method, each UE can indicate a NACK through a transmission resource predetermined for each UE, and thus can indicate to a base station which one of the UEs did not successfully receive MBS data.

[0489] A base station can configure a transmission resource through which a UE can indicate successful reception (ACK) or unsuccessful reception (NACK) of MBS data as a common transmission resource for UEs receiving an MBS. Furthermore, through the common transmission resource, when at least one UE indicates a NACK or a predetermined UE indicates a NACK, the base station can retransmit MBS data. According to another method, when a UE does not successfully receive MBS data, and when the UE that did not successfully receive MBS data is indicated to a base station, the base station can retransmit MBS data only to the corresponding UE.

[0490] A base station can apply one or a combination of the following methods in order to perform retransmission of MBS data.

[0491] 1. First retransmission method (1q-01): The base station can transmit MBS data through a transmission resource configured by using system information, an RRC message, or MBS control data (time resource, frequency resource, subcarrier spacing, DRX configuration information, etc.) or through a configured period, or can indicate a transmission resource for MBS through a PDCCH scrambled by an RNTI indicating MBS data and transmit MBS data through the transmission resource (1q-05, 1q-10, 1q-30, and 1q-35). The UE can receive MBS data through a transmission resource configured by using system information, an RRC message, or MBS control data (time resource, frequency resource, subcarrier spacing, DRX configuration information, etc.) or through a configured period, or can configure a transmission resource for MBS through a PDCCH scrambled by an RNTI indicating MBS data and can receive MBS data through the transmission resource (1q-05, 1q-10, 1q-30, and 1q-35). When the UE does not successfully receive MBS data,...

Claims

1.A method performed by a user equipment, UE, in a wireless communication system, the method comprising: receiving configuration information for a multicast broadcast service, MBS; and receiving the MBS in a radio resource control, RRC, connected mode based on the configuration information, wherein the MBS is received via a multicast transmission to a plurality of UEs including the UE, wherein a hybrid automatic repeat request, HARQ, retransmission is applied to the multicast transmission of the MBS, wherein a service data adaptation protocol, SDAP, entity is configured for a bearer of the MBS, and wherein a quality of service, QoS, flow is mapped to the bearer of the MBS. 2.The method of claim 1, wherein a packet data convergence protocol, PDCP, entity is configured for the bearer of the MBS. 3.The method of claim 2, wherein the PDCP entity provides a header compression function by using a robust header compression, ROHC, or an Ethernet header compression, EHC, and a PDCP reordering function. 4.The method of claim 1, wherein the bearer of the MBS includes at least one of a radio link control, RLC, acknowledged mode, AM, or a RLC unacknowledged mode, UM, for dynamic switching between a unicast transmission and a multicast transmission. 5.The method of claim 4, wherein the MBS is scheduled by using a cell radio network temporary identifier, C-RNTI, for the unicast transmission and an MBS radio network temporary identifier, MBS-RNTI, for the multicast transmission. 6.A method performed by a base station in a wireless communication system, the method comprising: transmitting, to a user equipment, UE, configuration information for a multicast broadcast service, MBS; and transmitting the MBS in a radio resource control, RRC, connected mode based on the configuration information, wherein the MBS is transmitted via a multicast transmission to a plurality of UEs including the UE, wherein a hybrid automatic repeat request, HARQ, retransmission is applied to the multicast transmission of the MBS, wherein a service data adaptation protocol, SDAP, entity is configured for a bearer of the MBS, and wherein a quality of service, QoS, flow is mapped to the bearer of the MBS. 7.The method of claim 6, wherein a packet data convergence protocol, PDCP, entity is configured for the bearer of the MBS. 8.The method of claim 7, wherein, the PDCP entity provides a header compression function by using a robust header compression, ROHC, or an Ethernet header compression, EHC, and a PDCP reordering function. 9.The method of claim 6, wherein the bearer of the MBS includes at least one of a radio link control, RLC, acknowledged mode, AM, or a RLC unacknowledged mode, UM, for dynamic switching between a unicast transmission and a multicast transmission. 10.The method of claim 9, wherein, the MBS is scheduled by using a cell radio network temporary identifier, C-RNTI, for the unicast transmission and an MBS radio network temporary identifier, MBS-RNTI, for the multicast transmission. 11.A user equipment (UE) in a wireless communication system, the UE comprising: a transceiver; and at least one processor operably connected with the transceiver and configured to: receive configuration information for a multicast-broadcast service (MBS), and receive the MBS in a radio resource control (RRC) connected mode based on the configuration information, wherein the MBS is received via multicast transmission to a plurality of UEs including the UE, wherein hybrid automatic repeat request (HARQ) retransmission is applied to the multicast transmission of the MBS, wherein a service data adaptation protocol (SDAP) entity is configured for a bearer of the MBS, and wherein a quality of service (QoS) flow is mapped to the bearer of the MBS. 12.The UE of claim 11, wherein a packet data convergence protocol (PDCP) entity is configured for the bearer of the MBS. 13.The UE of claim 12, wherein the PDCP entity provides a header compression function by using robust header compression (ROHC) or Ethernet header compression (EHC) and PDCP reordering function. 14.The UE of claim 11, wherein the bearer of the MBS includes at least one of a radio link control (RLC) acknowledged mode (AM) or a RLC unacknowledged mode (UM) for dynamic switching between unicast transmission and multicast transmission. 15.The UE of claim 14, wherein the MBS is scheduled by using a cell radio network temporary identifier (C-RNTI) for the unicast transmission and an MBS radio network temporary identifier (MBS-RNTI) for the multicast transmission. 16.A base station in a wireless communication system, the base station comprising: a transceiver; and at least one processor operably connected with the transceiver and configured to: transmit configuration information for a multicast-broadcast service (MBS) to a user equipment (UE), and transmit the MBS in a radio resource control (RRC) connected mode based on the configuration information, wherein the MBS is transmitted via multicast transmission to a plurality of UEs including the UE, wherein hybrid automatic repeat request (HARQ) retransmission is applied to the multicast transmission of the MBS, wherein a service data adaptation protocol (SDAP) entity is configured for a bearer of the MBS, and wherein a quality of service (QoS) flow is mapped to the bearer of the MBS. 17.The base station of claim 16, wherein a packet data convergence protocol (PDCP) entity is configured for the bearer of the MBS. 18.The base station of claim 17, wherein, the PDCP entity provides a header compression function by using robust header compression (ROHC) or Ethernet header compression (EHC) and PDCP reordering function. 19.The base station of claim 16, wherein the bearer of the MBS includes at least one of a radio link control (RLC) acknowledged mode (AM) or a RLC unacknowledged mode (UM) for dynamic switching between unicast transmission and multicast transmission. 20.The base station of claim 19, wherein The MBS is scheduled by using a cell radio network temporary identifier, C-RNTI, for the unicast transmission and an MBS radio network temporary identifier, MBS-RNTI, for the multicast transmission.

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