Method and apparatus for event-based layer 1 measurement and reporting in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate.

Description

Method and apparatus for event-based Layer 1 measurement and reporting in a wireless communication system

[0001] The present disclosure relates to a wireless communication system and to the operation of a terminal and a base station in a wireless communication system. Specifically, it relates to a method and apparatus for an event-based layer 1 measurement and reporting procedure in a wireless communication system.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in frequency bands below 6 GHz ('Sub 6 GHz'), such as 3.5 gigahertz (3.5 GHz), but also in ultra-high frequency bands called millimeter waves (mmWave), such as 28 GHz and 39 GHz ('Above 6 GHz'). In addition, for 6G mobile communication technology, which is referred to as a system beyond 5G, implementation in the terahertz band (e.g., the 3 terahertz (3 THz) band at 95 GHz) is being considered to achieve transmission speeds 50 times faster and ultra-low latency reduced to one-tenth compared to 5G mobile communication technology.

[0003] In the early stages of 5G mobile communication technology, aiming to satisfy service support and performance requirements for enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), technologies included beamforming and massive MIMO to mitigate path loss and increase transmission distance in ultra-high frequency bands; support for various numerologies (such as operating multiple subcarrier spacings) and dynamic operation of slot formats for the efficient utilization of ultra-high frequency resources; initial access technologies to support multi-beam transmission and broadband; definition and operation of band-width parts (BWPs); new channel coding methods such as low-density parity check (LDPC) codes for high-volume data transmission and polar codes for reliable transmission of control information; L2 pre-processing; and networks providing dedicated networks specialized for specific services. Standardization of network slicing and the like has been carried out.

[0004] Currently, discussions are underway to improve and enhance the performance of the initial 5G mobile communication technology, taking into account the services that the 5G mobile communication technology was intended to support. Additionally, standardization of the physical layer is in progress for technologies such as V2X (vehicle-to-everything), which helps autonomous vehicles make driving decisions and enhance user convenience based on their own location and status information transmitted by the vehicle; NR-U (new radio unlicensed), which aims for system operation in unlicensed bands that meets various regulatory requirements; NR terminal low power consumption technology (UE power saving); non-terrestrial network (NTN), which is direct terminal-satellite communication for securing coverage in areas where communication with the terrestrial network is impossible; and positioning.

[0005] In addition, standardization is underway in the field of wireless interface architecture / protocols for technologies such as the Industrial Internet of Things (IIoT) for supporting new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) which provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement including conditional handover and Dual Active Protocol Stack (DAPS) handover, and 2-step Random Access (2-step RACH for NR) which simplifies random access procedures. Standardization is also underway in the field of system architecture / services for 5G baseline architectures (e.g., service-based architecture, service-based interface) for incorporating network functions virtualization (NFV) and software-defined networking (SDN) technologies, and Mobile Edge Computing (MEC), which provides services based on the location of the terminal.

[0006] When such 5G mobile communication systems are commercialized, connected devices, which are increasing explosively, will be connected to communication networks. Accordingly, it is expected that there will be a need to enhance the functionality and performance of 5G mobile communication systems and to integrate the operation of connected devices. To this end, new research is planned to be conducted on 5G performance improvement and complexity reduction, support for AI services, support for metaverse services, and drone communication using extended reality (XR), artificial intelligence (AI), and machine learning (ML) to efficiently support augmented reality (AR), virtual reality (VR), and mixed reality (MR).

[0007] In addition, the advancement of these 5G mobile communication systems can serve as a foundation for the development of new waveforms for ensuring coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas, metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using OAM (orbital angular momentum), and reconfigurable intelligent surface (RIS) technology to improve coverage of terahertz band signals, as well as full-duplex technology for improving frequency efficiency and system networks of 6G mobile communication technology, AI-based communication technology that realizes system optimization by utilizing satellites and artificial intelligence (AI) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology that realizes services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources.

[0008] The present disclosure considers detailed operations for setting up event-based Layer 1 measurement reporting, as LTM (L1 / L2 triggered mobility, L1 / L2-based mobility) is determined based on Layer 1-based measurement values ​​when LTM is performed at a terminal.

[0009] A method according to one embodiment for solving the above-mentioned problem is characterized in that, in a method for processing a control signal in a wireless communication system, the method comprises the steps of receiving a first control signal transmitted from a base station, processing the received first control signal, generating a second signal based on the processing, and transmitting the generated second control signal to the base station.

[0010] According to the embodiments proposed in this disclosure, as the entire terminal operation for setting up event-based Layer 1 measurement reporting is specified, the terminal can perform LTM (L1 / L2 triggered mobility) event-based measurement reporting. In addition, according to the embodiments proposed in this disclosure, a procedure is proposed to more accurately trigger LTM through LTM event-based measurement reporting.

[0011] FIG. 1 illustrates the structure of a wireless communication system related to the present disclosure.

[0012] FIG. 2 illustrates the wireless protocol structure of a wireless communication system related to the present disclosure.

[0013] FIG. 3 illustrates the structure of another wireless communication system related to the present disclosure.

[0014] FIG. 4 illustrates a scenario for inter-cell beam management in a wireless communication system according to various embodiments of the present disclosure.

[0015] FIG. 5 illustrates a scenario in which a terminal in a wireless communication system according to various embodiments of the present disclosure changes the serving cell and beam to a TRP (transmission reception point) of a cell that supports L1 (layer 1) / L2 (layer 2) based beam changing to transmit and / or receive data.

[0016] FIG. 6a illustrates the overall operation for performing event-based L1 measurement reporting in LTM (L1 / L2 triggered mobility) in a wireless communication system according to various embodiments of the present disclosure.

[0017] FIG. 6b illustrates the overall operation for performing event-based L1 measurement reporting in an LTM in a wireless communication system according to various embodiments of the present disclosure.

[0018] FIG. 7 illustrates the overall terminal operation of performing an event-based L1 measurement report to perform an L1 / L2-based handover in a wireless communication system according to various embodiments of the present disclosure.

[0019] FIG. 8 illustrates base station operation in a wireless communication system according to various embodiments of the present disclosure.

[0020] FIG. 9 is a block diagram illustrating the internal structure of a terminal in a wireless communication system according to various embodiments of the present disclosure.

[0021] FIG. 10 is a block diagram showing the configuration of a base station in a wireless communication system according to various embodiments of the present disclosure.

[0022] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0023] In describing the embodiments, technical details that are well known in the art to which this disclosure belongs and are not directly related to this disclosure are omitted. This is intended to convey the essence of this disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0024] For the same reason, some components in the attached drawings have been exaggerated, omitted, or schematically depicted. Additionally, the dimensions of each component do not entirely reflect their actual dimensions. Identical or corresponding components in each drawing have been assigned the same reference numbers.

[0025] The advantages and features of the present disclosure, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components. Furthermore, in describing the present disclosure, if it is determined that a detailed description of a related function or configuration might unnecessarily obscure the essence of the present disclosure, such detailed description is omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or conventions of the user or operator. Therefore, their definitions should be based on the content throughout the specification.

[0026] Hereinafter, a base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, eNode B, Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. A terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. In this disclosure, a downlink (DL) refers to a wireless transmission path of a signal transmitted by a base station to a terminal, and an uplink (UL) refers to a wireless transmission path of a signal transmitted by a terminal to a base station. Furthermore, while LTE or LTE-A systems may be described as examples below, embodiments of this disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, 5th generation mobile communication technologies (5G, new radio, NR) developed after LTE-A may be included therein, and the 5G below may be a concept that includes existing LTE, LTE-A, and other similar services. In addition, the present disclosure may be applied to other communication systems with some modifications made at the discretion of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure. The contents of the present disclosure are applicable to FDD and TDD systems.

[0027] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0028] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to their corresponding functions.

[0029] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and '~parts' may be implemented to utilize one or more CPUs (central processing units) within the device or secure multimedia card. Also, in the embodiments, the '~part' may include one or more processors.

[0030] Wireless communication systems are evolving from providing early voice-oriented services to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards like 3GPP’s HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2’s HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE’s 802.16e.

[0031] As a representative example of the above-mentioned broadband wireless communication system, the LTE system employs the Orthogonal Frequency Division Multiplexing (OFDM) method for the downlink (DL) and the Single Carrier Frequency Division Multiple Access (SC-FDMA) method for the uplink (UL). The uplink refers to a wireless link through which a terminal (User Equipment (UE) or Mobile Station (MS)) transmits data or control signals to a base station (eNode B, or base station (BS)), and the downlink refers to a wireless link through which a base station transmits data or control signals to a terminal. The above-mentioned multiple access method can distinguish the data or control information of each user by allocating and operating time-frequency resources to be sent for each user so that they do not overlap, that is, so that orthogonality is established.

[0032] As a future communication system following LTE, that is, a 5G communication system, it must be able to freely reflect the diverse requirements of users and service providers, and therefore, services that satisfy various requirements simultaneously must be supported. Services being considered for the 5G communication system include enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC).

[0033] eMBB aims to provide data transmission speeds that are superior to those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to provide a peak data rate of 20 Gbps in the downlink and 10 Gbps in the uplink from the perspective of a single base station. Furthermore, while providing these peak data rates, the 5G communication system must also provide an increased user-perceived data rate. To satisfy these requirements, it necessitates improvements in various transmission and / or reception technologies, including enhanced Multi-Input Multi-Output (MIMO) transmission technology. Additionally, while LTE transmits signals using a maximum bandwidth of 20 MHz in the 2 GHz band, the 5G communication system can meet the data transmission speeds required by using a frequency bandwidth wider than 20 MHz in frequency bands of 3–6 GHz or above 6 GHz.

[0034] Simultaneously, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide IoT, mMTC requires support for a large number of terminal connections within a cell, improved terminal coverage, enhanced battery life, and reduced terminal costs. Since IoT devices are attached to various sensors and equipment to provide communication functions, the system must be able to support a large number of terminals within a cell (e.g., 1,000,000 terminals / km²). Furthermore, due to the nature of the service, terminals supporting mMTC are likely to be located in dead zones not covered by cells, such as building basements; therefore, they may require wider coverage compared to other services provided by 5G communication systems. Terminals supporting mMTC must consist of low-cost devices, and since it is difficult to frequently replace terminal batteries, a very long battery life of 10 to 15 years may be required.

[0035] Finally, URLLC is a mission-critical cellular-based wireless communication service. Examples include services used for remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts. Therefore, the communication provided by URLLC must offer very low latency and very high reliability. For instance, services supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds and simultaneously require a packet error rate of 10^-5 or less. Consequently, for services supporting URLLC, 5G systems must provide a Transmit Time Interval (TTI) smaller than other services, and design considerations may be required to allocate wide resources in the frequency band to ensure the reliability of the communication link.

[0036] The three 5G services, namely eMBB, URLLC, and mMTC, can be multiplexed and transmitted within a single system. In this case, different transmission and / or reception techniques and transmission and / or reception parameters may be used between the services to satisfy the different requirements of each service. Of course, 5G is not limited to the three services mentioned above.

[0037] Hereinafter, a / b may be understood as at least one of a or b.

[0038] In addition, for the convenience of the following description, the present disclosure uses terms and names defined in the 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) standard. However, the present disclosure is not limited to the above terms and names and may be applied equally to systems conforming to other standards.

[0039] FIG. 1 illustrates the structure of a wireless communication system related to the present disclosure.

[0040] Referring to FIG. 1, as illustrated, the wireless access network of the wireless communication system consists of a next-generation base station (new radio node B, hereinafter NR NB, 1-10) and an NR CN (new radio core network, or NG CN: next generation core network, 1-05). A user terminal (new radio user equipment, hereinafter NR UE or terminal, 115) connects to an external network through the NR NB (110) and the NR CN (105).

[0041] In FIG. 1, the NR NB (110) corresponds to the eNB (evolved node B) of the existing LTE system. The NR NB is connected to the NR UE (115) via a wireless channel and can provide superior service compared to the existing node B. In a wireless communication system, since all user traffic is serviced through a shared channel, a device is required to collect state information such as the buffer status, available transmission power status, and channel status of the UEs and perform scheduling, and this is handled by the NR NB (110). A single NR NB typically controls multiple cells. To achieve ultra-high-speed data transmission compared to existing LTE, it can have a maximum bandwidth greater than that of existing LTE, and orthogonal frequency division multiplexing (hereinafter referred to as OFDM) can be used as a wireless access technology, and beamforming technology can be additionally incorporated. Additionally, an adaptive modulation & coding (hereinafter referred to as AMC) method is applied to determine the modulation scheme and channel coding rate according to the terminal's channel status. The NR CN (105) performs functions such as mobility support, bearer configuration, and QoS (quality of service) configuration. The NR CN is a device responsible for various control functions as well as mobility management functions for terminals, and is connected to multiple base stations. Additionally, the wireless communication system can be linked with the existing LTE system, and the NR CN is connected to the MME (125) via a network interface. The MME is connected to the existing base station, eNB (130).

[0042] FIG. 2 illustrates the wireless protocol structure of a wireless communication system related to the present disclosure.

[0043] Referring to FIG. 2, the wireless protocol of the wireless communication system consists of NR SDAP (service data adaptation protocol) (201, 245), NR PDCP (packet data convergence protocol) (205, 240), NR RLC (radio link control) (210, 235), and NR MAC (medum access control) (215, 230) at the terminal and the NR base station, respectively.

[0044] The main functions of NR SDAP (201, 245) may include some of the following functions.

[0045] - User data transfer function (transfer of user plane data)

[0046] - Mapping function between a QoS flow and a DRB for both DL and UL for uplink and downlink

[0047] - Marking QoS flow ID for uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0048] - Function to map reflective QoS flow to data bearers for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0049] Regarding the above SDAP layer device, the terminal may receive a radio resource control (RRC) message indicating whether to use the header of the SDAP layer device or the functions of the SDAP layer device for each PDCP layer device, for each bearer, or for each logical channel. If the SDAP header is configured, the terminal may be instructed to update or reset the mapping information for the uplink and downlink QoS flows and data bearers using the NAS reflective QoS and AS reflective QoS 1-bit indicators of the SDAP header. The above SDAP header may include QoS flow ID information indicating QoS. The above QoS information may be used for data processing priority, scheduling information, etc., to support smooth service.

[0050] The main functions of NR PDCP (205, 240) may include some of the following functions.

[0051] - Header compression and decompression features (ROHC only)

[0052] - User data transfer function (Transfer of user data)

[0053] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0054] - Out-of-sequence delivery of upper layer PDUs

[0055] - Reordering function (PDCP PDU reordering for reception)

[0056] - Duplicate detection function (Duplicate detection of lower layer SDUs)

[0057] - Retransmission of PDCP SDUs

[0058] - Encryption and decryption functions (Ciphering and deciphering)

[0059] - Timer-based SDU discard in uplink.

[0060] In the above, the reordering function of the NR PDCP device refers to a function of reordering PDCP PDUs received from a lower layer in order based on the PDCP SN (sequence number), and may include a function of transmitting data to an upper layer in the reordered order, a function of transmitting immediately without considering the order, a function of recording lost PDCP PDUs by reordering, a function of reporting the status of lost PDCP PDUs to the transmitting side, and a function of requesting retransmission of lost PDCP PDUs.

[0061] The main functions of NR RLC (210, 235) may include some of the following functions.

[0062] - Data transfer function (Transfer of upper layer PDUs)

[0063] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0064] - Out-of-sequence delivery of upper layer PDUs

[0065] - ARQ function (Error Correction through ARQ)

[0066] - Concatenation, segmentation, and reassembly functions of RLC SDUs

[0067] - Re-segmentation function (Re-segmentation of RLC data PDUs)

[0068] - Reordering function (Reordering of RLC data PDUs)

[0069] - Duplicate detection

[0070] - Error detection function (Protocol error detection)

[0071] - LC SDU deletion function (RLC SDU discard)

[0072] RLC re-establishment function

[0073] In the above, the in-sequence delivery function of the NR RLC device refers to the function of delivering RLC SDUs received from a lower layer to an upper layer in order, and may include the function of reassembling and delivering them when a single RLC SDU is received divided into multiple RLC SDUs. In addition, the in-sequence delivery function of the NR RLC device may include the function of rearranging the received RLC PDUs based on the RLC SN (sequence number) or PDCP SN (sequence number), the function of recording lost RLC PDUs by rearranging the order, the function of reporting the status of lost RLC PDUs to the transmitting side, and the function of requesting retransmission of lost RLC PDUs. In addition, the sequential delivery function of the NR RLC device may include a function to deliver only the RLC SDUs prior to the lost RLC SDU in order to the upper layer if there is a lost RLC SDU, or a function to deliver all RLC SDUs received before the timer started in order to the upper layer if a predetermined timer has expired even if there is a lost RLC SDU, or a function to deliver all RLC SDUs received up to now in order to the upper layer if a predetermined timer has expired even if there is a lost RLC SDU. In addition, the RLC PDUs may be processed in the order they are received (regardless of the order of the sequence number, in the order of arrival) and delivered to the PDCP device out of order (out-of-sequence delivery), and in the case of segments, segments stored in a buffer or to be received later may be received, reconstructed into a single complete RLC PDU, processed, and delivered to the PDCP device.The above NR RLC layer may not include a concatenation function, and the function may be performed in the NR MAC layer or replaced by the multiplexing function of the NR MAC layer.

[0074] In the above, the out-of-sequence delivery function of the NR RLC device refers to a function of delivering RLC SDUs received from a lower layer directly to an upper layer regardless of order, and may include a function of reassembling and delivering them when a single RLC SDU is received divided into multiple RLC SDUs, and a function of storing the RLC SN or PDCP SN of the received RLC PDUs and sorting the order to record the lost RLC PDUs.

[0075] The NR MAC (215, 230) can be connected to multiple NR RLC layer devices configured in a terminal, and the main functions of the NR MAC may include some of the following functions.

[0076] - Mapping function (Mapping between logical channels and transport channels)

[0077] - Multiplexing and demultiplexing functions (Multiplexing / demultiplexing of MAC SDUs)

[0078] - Scheduling information reporting function

[0079] - HARQ function (Error correction through HARQ)

[0080] - Priority handling between logical channels of one UE

[0081] - Priority handling between UEs by means of dynamic scheduling

[0082] - MBMS service identification function

[0083] - Transport format selection function

[0084] - Padding

[0085] The NR PHY layer (220, 225) can perform the operation of channel coding and modulating upper layer data, making it into OFDM symbols and transmitting it to the wireless channel, or demodulating OFDM symbols received through the wireless channel and channel decoding them to transmit them to the upper layer.

[0086] FIG. 3 illustrates the structure of another wireless communication system related to the present disclosure.

[0087] Referring to FIG. 3, a cell serviced by a beam-based NR gNB (305) may be composed of multiple TRPs (transmission and reception points, 310, 315, 320, 325, 330, 335, 340). The TRPs (310 to 340) represent blocks that separate some functions of transmitting and / or receiving physical signals from an existing NR base station (gNB), and are composed of multiple antennas. The NR gNB (305) may also be represented as a CU (central unit) and the TRP as a DU (distributed unit). The functions of the NR gNB (305) and the TRPs may be configured by separating each layer from the PDCP / RLC / MAC / PHY layer, such as 345. That is, the above TRP can perform the functions of the corresponding layer using only the PHY layer (315, 325), the above TRP can perform the functions of the corresponding layers using only the PHY layer and the MAC layer (310, 335, 340), and the above TRP can perform the functions of the corresponding layers using only the PHY layer, the MAC layer, and the RLC layer (320, 330). In particular, the TRP (310~340) can use beamforming technology to transmit and / or receive data by generating narrow beams in multiple directions using multiple transmitting and receiving antennas. The user terminal (350) connects to the NR gNB (305) and the external network through the TRP (310~340). The above NR gNB (305) collects status information such as the buffer status, available transmission power status, and channel status of terminals to provide services to users, schedules them, and supports the connection between the terminals and the core network (CN), particularly the AMF / SMF (355).

[0088] The TRP in the present disclosure is based on a structure (315, 325) that has only a PHY layer and can perform the functions of that layer.

[0089] FIG. 4 illustrates a scenario for inter-cell beam management in a wireless communication system according to various embodiments of the present disclosure. More specifically, with reference to FIG. 4, a scenario is illustrated in which a terminal transmits and / or receives data through the beam of a TRP of a neighboring cell that supports beam changing based on L1 / L2 while maintaining a connection state with a serving cell.

[0090] Although the present disclosure describes a case where multiple cells (TRP1-Cell1, TRP2-Cell2; 410, 415) exist within a single DU (405), the overall content of the present disclosure is also applicable to inter-DU cases (each DU constitutes a single TRP-Cell). Furthermore, throughout the present disclosure, non-serving cells (TRP 2, Cell 2) that support L1 / L2-based mobility (beam change and serving cell change) may be referred to interchangeably as neighbor cells, non-serving cells, additional cells with the PCI different from the serving cell, etc.

[0091] In the existing terminal beam change procedure (445), the terminal (420) is in a connected state through the TRP 1 (410) of serving cell 1 and may be set to the optimal beam, which is the transmission configuration indicator (TCI) state 1 (425, 430). At this time, the terminal may receive instructions for setting information for L3 channel measurement (RRM; radio resource management) for an additional cell (TRP 2-Cell 2, 415) that has a different PCI from the serving cell through RRC setting information from the serving cell (410), and may perform an L3 measurement operation (446) for the corresponding frequency and cell. Subsequently, the serving cell (TRP 1-Cell 1, 410) may direct a handover to the corresponding cell (TRP 2-Cell 2, 415) based on the reported measurement value (447), and once the handover is completed, additional RRC configuration information may be transmitted to the terminal (420) via TRP 2-Cell 2 (415) (448). The RRC configuration information may include UL / DL configuration information in the corresponding cell, L1 measurement related settings (e.g., CSI-RS measurement and reporting), and in particular, may include TCI state configuration information for the PDCCH (physical downlink control channel) and PDSCH (physical downlink shared channel). The terminal (420) may perform an L1 measurement (449) according to the settings. Additionally, the base station may update the TCI state through L1 / L2 signaling according to the measurement report (450). At this time, the optimal beam, TCI state 2 (440), can be indicated. At this stage, the serving cell is Cell 1 until the handover, and Cell 2 becomes the serving cell after the handover. Therefore, many procedures and time may be required even after the handover to indicate the optimal beam.

[0092] Unlike the existing terminal beam change procedure (445) described above, the improved beam change technique (455) considered in this disclosure is as follows. For example, the terminal (420) can refer to and transmit a beam setting associated with an additional cell (TRP 2-Cell 2, 415) with a different PCI from the serving cell through RRC setting information (456) from the serving cell (410). The beam setting associated with the additional cell (TRP 2-Cell 2, 415) with a different PCI from the serving cell (for example, the part that associates the TCI state corresponding to TRP2) may be indicated by a method of associating a new cell ID (Physical cell ID, PCI; additionalPCI-r17) as shown in Table 1 below.

[0093]

[0094] In addition, a unified TCI state framework may be applied for beam management between the cells. The unified TCI state framework applies a common TCI state framework to the uplink and downlink, as well as to the common channel and dedicated channel, and can be configured as either Joint UL / DL mode or separate UL / DL mode as shown in Table 2 below.

[0095]

[0096] 1. Joint UL / DL Mode: Configure UL and DL to share the same TCI settings (in PDSCH-Config) (see Table 3 below)

[0097]

[0098] 2. Separate UL / DL mode: UL and DL each provide their own TCI settings [see Table 4 below]. The TCI state for DL ​​follows the settings in dl-OrJoint-TCIStateList-r17 (in PDSCH-Config), and the TCI state for UL can follow ul-TCI-StateList-r17 (in BWP-UplinkDedicated).

[0099]

[0100] After the settings for TRP 2-Cell 2 are provided in the RRC connection state to serving cell 1, the terminal (420) can perform an L1 measurement for the corresponding TRP 2-Cell 2 according to the settings and report the measurement results to the serving cell (Cell 1, 410) (457). If the serving cell determines that a change to a specific beam (TCI state 2, 435, 440) of TRP 2 (Cell 2, 415) is necessary from the serving cell beam (TCI state 1, 425, 430) according to the measurement results, it can trigger a beam change and instruct the terminal (420) via L1 / L2 signaling (458). The terminal (420) can change the beam to a specific beam (TCI state 2, 440) of TRP 2 (Cell 2, 415) via the corresponding instruction (458), and perform physical channel setting and upper layer setting operations associated with the set beam. From that stage, the terminal (420) remains connected to the serving cell (Cell 1, 410), but can perform data transmission and / or reception using the channel link of TRP 2 (Cell 2, 415) (PDCCH / PDSCH reception, PUCCH / PUSCH transmission). For example, transmission and / or reception for the common control channel can be performed through the serving cell (Cell 1, 410). Subsequently, the terminal (420) can perform L3 measurement operations according to the measurement settings set in the independent serving cell (459), receive a handover command message from the serving base station (Cell 1), and perform a serving cell change to Cell 2 (460). Through this technique (455), the terminal (420) can perform data transmission and / or reception with a specific TRP 2 of Cell 2 that supports L1 / L2-based mobility while connected to a serving cell. Additionally, the terminal (420) can continuously use the beam used for data transmission and / or reception with the TRP 2 even after a handover.

[0101] For reference, the RRC settings regarding the settings and operations related to the L1 measurement and report in step 457 above are described in Tables 5 and 6 below. These contents are basically applied to the embodiments below of the present disclosure, and enhancement techniques may be added in future embodiments.

[0102] 1. L1 measurement settings (configured within CSI-ResourceConfig and ServingCellConfig in IE)

[0103] - CSI-RS / SSB resources and resource pools requiring measurement (nzp-CSI-RS, csi-IM, csi-SSB)

[0104] - Configuration of CSI-RS / SSB resources requiring measurement (aperiodic, semi-persistent) and triggering settings

[0105] - When a CSI-RS resource references an SSB resource, it provides additional PCI information to enable L1 measurements from neighboring cells (up to 7 additional neighboring cells (PCI) can be added from a single serving cell).

[0106]

[0107]

[0108] 2. L1 report settings (configured within the serving cell, ServingCellConfig, configured within IE)

[0109] - Report Type: Periodic Report, Semi-periodic Report with PUCCH, Semi-periodic Report with PUSCH, Aperiodic Report with PUSCH

[0110] - Report quantity

[0111] - Other settings required for reporting

[0112] FIG. 5 illustrates a scenario in which a terminal in a wireless communication system according to various embodiments of the present disclosure transmits and / or receives data by changing the serving cell and beam to the TRP of a cell that supports L1 / L2-based beam changing. Although the present disclosure describes a case where multiple cells (TRP1-Cell1, TRP2-Cell2; 510, 515, 540, 545) exist within a single DU (505, 535), the general content of the present disclosure is also applicable to inter-DU within an intra-CU (each DU constitutes a single TRP-Cell).

[0113] Unlike the conventional terminal beam changing procedure (445, 455) described in FIG. 4, the improved beam changing technique (525, 575) considered in these embodiments is as follows.

[0114] 1. Example 1 (525): After performing inter-cell beam management (change) operation, perform L1 / L2 handover

[0115] 2. Example 2 (575): Perform L1 / L2 handover immediately

[0116] First, to describe the overall operation of Example 1, the terminal (520) can receive common configuration and dedicated configuration information for an additional cell (TRP 2-Cell 2, 515) that has a different PCI from the serving cell (510) through RRC configuration information (526). For example, configuration information corresponding to ServingCellID or candidateCellID (cell ID associated with PCI), ServingCellConfigCommon, and ServingCellConfig may be provided in advance. The configuration information may be provided in the form of pre-configuration in the RRC configuration and may include configuration information for multiple cells. In addition, the configuration may be characterized by including all configuration information (e.g., cell configuration, bearer configuration, security key configuration, etc.) that is applied when the terminal (520) moves to the cell (handover). Furthermore, the configuration may include enhanced configurations by referring to the unified TCI state configuration and L1 measurement and report related settings described in step 456 of Figure 4. More specifically, for continuous LTM, an enhanced unified TCI state setting and L1 measurement and report settings are included, which are described in detail in the drawings below of the present disclosure.

[0117] After the setting for TRP 2-Cell 2 (515) is provided in the RRC connection state to serving cell 1, the terminal (520) performs an L1 measurement for the corresponding TRP 2-Cell 2 (515) according to the setting received in step 527 and reports the measurement result to the serving cell (Cell 1, 510). If the serving cell determines that a change to a specific beam (TCI state 2, 540) of TRP 2 (Cell 2, 515) is necessary from the serving cell beam (TCI state 1, 525) based on the measurement result, it may trigger a beam change in step 528 and instruct the terminal (520) via L1 / L2 signaling. The terminal (520) can perform a beam change to TRP 2 (Cell 2, 515) via the corresponding instruction (528) and transmit and / or receive data through the TRP 2 (Cell 2, 515). At this time, no serving cell change occurs, and the terminal may still remain RRC connected to the serving cell (Cell 1, 510). Subsequently, the terminal may still perform an L1 measurement for TRP 2-Cell 2 (515) and report the result to the serving cell (Cell 1, 510). If the L1 measurement reported by the terminal satisfies a triggering condition for a handover to TRP 2-Cell 2 (515) (specific actions are described in detail below), the serving cell (Cell 1, 510) may instruct the terminal to perform a handover. The instruction may be an L1 / L2 message. For example, a MAC (medium access control) CE (control element) may include an indicator that directs a handover.

[0118] To describe the overall operation of Example 2, the terminal (550) can receive common configuration and dedicated configuration information for an additional cell (TRP 2-Cell 2, 545) that has a different PCI from the serving cell (540) through RRC configuration information (576). For example, ServingCellID or candidateCellID (cell ID associated with PCI), and configuration information corresponding to the corresponding candidate LTM cell may be provided in advance. The configuration information may be provided in the form of pre-configuration in the RRC configuration and may include configuration information for multiple cells. In addition, the configuration may be characterized by including all configuration information (e.g., cell configuration, bearer configuration, channel measurement configuration, etc.) that is applied when the terminal (550) moves to the corresponding cell (handover). Furthermore, the configuration may include the unified TCI state configuration and L1 measurement and report related settings described in step 456 of FIG. 4, modified to support consecutive LTMs. The L1 measurement, report, and TCI state settings applicable to the present disclosure are described in detail below.

[0119] After the setting for TRP 2-Cell 2 (545) is provided in the RRC connection state to serving cell 1, the terminal (550) can perform an L1 measurement for the TRP 2-Cell 2 (545) according to the setting received in step 577 and report the result to the serving cell (Cell 1, 540). If the serving cell determines that a handover is required simultaneously with a beam change from the serving cell beam (TCI state 1, 545) to a specific beam (TCI state 2, 570) of TRP 2 (Cell 2, 545) based on the measurement result, it can trigger the beam change and handover in step 578 and instruct the terminal via L1 / L2 signaling. The terminal (550) can perform a handover simultaneously with changing the beam to TRP 2 (Cell 2, 515) via the corresponding instruction (578) and transmit and / or receive data through the TRP 2 (Cell 2, 515). At this time, the terminal (550) may apply the configuration information for the target cell where the handover is performed, which was pre-configured in step 576. Depending on whether uplink synchronization is required in that step, the terminal (550) may perform random access, or random access to the target cell may be omitted. Detailed operation is described below in the drawings.

[0120] In particular, as explained above, a detailed method for setting the unified TCI state and L1 measurement and report for candidate cells surrounding the LTM to support the continuous LTM proposed in this disclosure is described. As illustrated in Figure 1d, in conventional ICBM (Inter-cell beam management), L1 measurement resource settings for cells requiring measurement can be provided in the CSI-ResourceConfig within the ServingCellConfig IE within the serving cell settings. In particular, to indicate resources for surrounding cells, the PCI of the cell where the L1 measurement resource provided in servingAdditionalPCIList is set can be indicated.

[0121] Detailed settings for L1 measurement and reporting settings for LTM can be provided as L1 measurement resource settings applied to LTM candidate cells as follows. To this end, it may be necessary to share and determine L1 measurement resources and reporting settings for LTM among LTM candidate cells during the preprocessing stage. The entire procedure can be described as in the following examples. In the following examples, the description refers to the corresponding settings among the following (e.g., Tables 7 to 10). Of course, it is not limited to the following examples.

[0122] 1. L1 measurement resource configuration (configured within LTM-CSI-ResourceConfig and LTM-Config)

[0123] - CSI Resource configuration index exists to specify CSI resource settings (LTM-CSI-ResourceConfigId-r18)

[0124] - CSI resource set containing CSI-RS or SSB resources requiring measurement

[0125] - A single CSI resource set can be multiple SSB resources or CSI-RS resources existing within an LTM candidate cell.

[0126] 2. L1 report settings (configured within LTM-Config)

[0127] - CSI Report configuration index exists to specify CSI reporting settings (LTM-CSI-ReportConfig-r18)

[0128] - Report Type: Periodic Report, Semi-periodic Report with PUCCH, Semi-periodic Report with PUSCH, Aperiodic Report with PUSCH

[0129] - Report Content (Number of reporting cells, number of reporting resources, etc.)

[0130]

[0131]

[0132]

[0133]

[0134]

[0135] The present disclosure proposes a method for setting L1 measurement information for surrounding candidate cells for LTM to support subsequent LTM (subsequent L1 / L2 triggered mobility) and a method for setting a terminal to report the set L1 measurement information. More specifically, a method for setting and reporting event-based L1 measurement information may be described, and in particular, details regarding the entire procedure and detailed information included in the event-triggered L1 measurement report are described.

[0136] FIGS. 6a and 6b illustrate the overall operation for performing event-based Layer 1 measurement reporting in an LTM in a wireless communication system according to various embodiments of the present disclosure. The present disclosure describes the overall operation of applying L1 measurement resources and reporting settings to support continuous L1 / L2-based handover (LTM) operations in cells within different CUs.

[0137] A terminal (601) in an RRC connection state can transmit and / or receive data with source cell 1 (602) and, in accordance with the layer 3 measurement and report set in step 610, transmit layer 3 measurement values ​​for the serving cell and surrounding cells to the source base station (603). At this time, the actual measurement values ​​can be transmitted to the base station CU (603). This is because the base station CU (603) is responsible for processing RRC messages and determining mobility. Based on the measurement value report received from the terminal, the base station CU (603) can generate a message (e.g., UE Context Setup Request or UE Context Modification Request) requesting configuration information for L1 / L2-based handover to intra-CU LTM candidate surrounding cells (604, 605) in step 615 and transmit it through the F1 interface. In FIGS. 6a and 6b, candidate cells are indicated in association with DUs, but in reality, candidate cells and DUs may have a 1:1 mapping, or multiple candidate cells may be included in a single DU. Additionally, the message requesting configuration information for the L1 / L2-based handover described above may be a UE context request message, a UE context modification request message, or a new F1 message. The message requesting configuration information for the L1 / L2-based handover may include a procedure to request neighboring cells that they have been determined as L1 / L2-based handover candidate cells, while simultaneously requesting RRC configuration information that applies when an L1 / L2-based handover is performed to the cell. For example, it may include information requesting L1 measurement resources and reporting settings for LTM candidate cells. The information that may be included in the message is summarized as follows. Of course, it is not limited to the examples below.

[0138] 1. Configuration information applicable to LTM and conditional LTM (This information may be displayed when issuing the cell switch command MAC CE instruction to the candidate cell that made the LTM decision.)

[0139] - LTM candidate ID

[0140] - Mapping information between the LTM candidate ID and the corresponding cell ID

[0141] - Beam information to be used for each candidate (TCI state)

[0142] -- In this case, the meaning of use may be a beam linked to the RACH occasion when performing DL and / or UL synchronization and / or RACH (random access channel), and / or a beam to be used for the first UL data transmission. If necessary, a cell switch may be performed accompanied by an indicator for each case.

[0143] - RACH preamble index

[0144] - SSB (synchronization signal block) index: An index of the SSB used to determine the RACH occasion in each candidate cell, which can represent the RACH preamble occasion of CFRA (contention-based random access).

[0145] 2. Pre-configuration procedures for LTM and conditional LTM

[0146] - CSI resource request information for each candidate cell (requests for CSI-RS resources or SSB resources)

[0147] -- This may be requested during the pre-configuration preprocessing section for LTM candidate cells.

[0148] --- An indicator of whether the request is for initial preparation (e.g., initiation) or for a modification request after the initial one

[0149] -- In particular, when the relevant request information is included, lower layer configuration information and CSI report configuration information in the message may not be transmitted.

[0150] -- If CSI resource information is received from candidate cells with the corresponding request information, the CSI resource settings of each of the following candidate cells may be delivered instead of the request. For example, a CSI resource setting preprocessing procedure may be required in at least 2 steps.

[0151] In addition, it can be determined whether to request CSI-RS resources or SSB resources for each target candidate cell.

[0152] - CSI resource settings for each candidate cell (e.g., required when transmitting L1 measurement settings as source DU to the terminal), individual resource settings per cell, and setting IDs, may be CSI resource settings for LTM, and may use the same CSI resources as conditional LTM, but may be transmitted with explicit distinction for conditional LTM.

[0153] -- Based on the above CSI resource request information, L1 measurement settings for LTM transmitted from the corresponding candidate cell are provided

[0154] -- Depending on the CSI-RS or SSB resource request from each target cell, one of the two resource configurations or both resource configurations may be delivered.

[0155] - CSI report configuration considering the CSI resources of each of the above candidate cells

[0156] The purpose of the CSI report configuration considering the CSI resources of each candidate cell is that when a candidate DU creates the above information and transmits it to the CU, this information can be used as the CSI report configuration within the target cell configuration (RRCReconfiguration) of the relevant concerned cell (e.g., target cell) created by the CU. Additionally, the information may not be transmitted separately but may be included and transmitted within the target cell configuration (RRCReconfiguration).

[0157] -- For example, when a terminal moves from another cell to the concerned cell, it can be used as a CSI report configuration with the concerned cell as the serving cell. This may be intended to include it in the target cell configuration without providing a separate L1 configuration for the Subsequent LTM.

[0158] -- Event-based L1 measurement reporting

[0159] Best beam's L1-RSRP-based events can be defined and used.

[0160] For example, events such as those shown in Table 11 below can be introduced. For instance, events can be defined by comparing the serving cell beam and the surrounding cell beam, and L1 filtering values ​​such as threshold, beam offset, hysteresis, and time to trigger (TTT) can be introduced.

[0161]

[0162] The above event may also be used for conditions that trigger a conditional LTM. Alternatively, in addition to a single beam, events through multiple beams or events through cell-level measurements estimated through multiple beams may be added.

[0163] The above conditions are determined by coordination between the serving CU and the LTM candidate DU in step 615, and the serving CU can confirm the event conditions and L1 filtering values ​​that trigger the LTM provided by the LTM candidate cell and transmit them to the terminal.

[0164] --- Information regarding the application of L3-based event conditions (conditions used in conditional handovers)

[0165] - RACH configuration and lower layer setting information to be used in the concerned cell

[0166] -- The RACH configuration and lower layer setting information to be used in the concerned cell can be transmitted from the candidate DU to the CU, and generated as at least one of the settings required for performing RACH within the target cell configuration of the concerned cell, the lower layer settings to be applied when moving to the cell, or a reference setting including them, and transmitted to the terminal.

[0167] -- In particular, some of the RACH settings can be used to include RACH preamble index, Mask, and occasion determination information in the cell switch command MAC CE described above.

[0168] -- It may be a setting that applies to both LTM and Conditional LTM simultaneously, but resources dedicated to Conditional LTM may also be configured separately.

[0169] Step 615 is described as a single procedure, but it can be applied to multiple procedures. For example, the base station CU (603) may request LTM-related settings for each LTM candidate cell (604, 605), transmit the settings organized from the source cell once again, and then determine the necessary LTM settings and transmit them to the source cell (602).

[0170] In an embodiment of the present disclosure, regarding event-based L1 measurement reporting, when a beam of a source cell is determined, specific beams of LTM candidate cells are measured, and how beams satisfying the conditions are finally reported in an event-based L1 measurement report can be explained. Additionally, an explanation of what information is included in the MAC CE used for event-based L1 measurement reporting can be included. For a detailed proposal, refer to FIG. 7 below.

[0171] Additionally, the base station CU (603) may generate a message (e.g., Handover Request or new message) requesting configuration information for LTM to the target base station (CU2; 606) in step 620 for an LTM candidate cell configuration request for an LTM neighbor cell (607) of the inter-CU based on a measurement value report received from the terminal, and transmit it through the X2 interface. Subsequently, in step 625, the target base station (CU2; 606) may generate a message (e.g., UE Context Setup Request or UE Context Modification Request) requesting configuration information for LTM cell modification for an LTM candidate cell (607) belonging to the corresponding CU (CU2), and transmit it through the F1 interface. Additionally, the target base station (CU2; 606) may receive a message (e.g., UE Context Setup Response or UE Context Modification Response) responding with configuration information for LTM from the LTM candidate cell (607) belonging to the corresponding CU (CU2). The above-described procedure (625) may be identical or similar to the LTM setting preprocessing procedure of 615 in FIG. 6a with the same intent. Subsequently, in step 630, the target base station (CU2; 606) may generate a message (e.g., Handover Response or a new response message) to be transmitted to the source base station (CU; 603), including the LTM candidate setting information content transmitted by the LTM candidate cell (607) belonging to the CU (CU2), and transmit it through the X2 interface. The content that may be newly added to the LTM setting request message through the X2 interface in step 630 may be as follows. Of course, it is not limited to the examples below.

[0172] - Indicator for LTM execution

[0173] -- Additionally, an indicator for whether the request is for initial preparation (e.g., initiation) or for modification after the initial request.

[0174] - Device ID

[0175] - Source CU and / or Source DU ID, and / or Source DU's TNL address (e.g., IP address)

[0176] - ID of the requesting candidate cell (PCI or NR CGI with NR ARFCN)

[0177] - LTM configuration ID of this candidate cell (for example, if accepted, the source DU can use the LTM config ID to the target cell during a cell switch.)

[0178] - LTM configuration ID mapping list: Information to inform the candidate DU of the mapping relationships between the candidate DU's currently available LTM configurations and its cells when delivered to the candidate DU.

[0179] -- Opt 1. The above candidate cell list may be a list of candidate cells operated by all candidate CUs for the terminal, and

[0180] -- Opt 2. It may be a list containing only candidate cells operated by the source CU that transmits the HO request message.

[0181] - Request information for CSI resource configuration for LTM L1 measurement

[0182] -- CSI resource requests are omitted, and configuration information for CSI resources being transmitted by all currently configured candidate cells may be conveyed.

[0183] -- SSB or CSI-RS resource request

[0184] -- Only one of the two resources may be requested, or both resources may be requested.

[0185] - An indicator requesting PRACH resource information for target candidate cells

[0186] - An indicator requesting a lower layer setting for target candidate cells

[0187] In addition to the information above, information previously used in HO request messages (see Table 12 below) may also be included.

[0188]

[0189]

[0190] Subsequently, in step 635, the source base station (602) may trigger the procedure of step 615 (transmitting the finally determined CSI resource settings to LTM candidate cells within the CU and requesting and responding to LTM-related settings) and step 620 (transmitting the finally determined CSI resource settings to LTM candidate cells within another CU and requesting LTM-related settings) based on the information of LTM-related candidate cells received from the target base station (606). Additionally, in response to this, the source base station (602) may perform the procedure of step 630 (receiving LTM-related settings based on the finally transmitted CSI resource settings from LTM candidate cells within another CU).

[0191] In step 640, the source base station (602) may collect all LTM-related settings received from LTM candidate cells and store them in an RRCReconfiguration message transmitted to the terminal (601), and may transmit the RRC setting information to the terminal (601). For example, pre-configuration information for LTM candidate cells may be transmitted to the terminal (601). At this time, the source base station CU (603) may transmit to the terminal (601) the setting information of the source cell and separate reference cell configuration information. In the present disclosure, the reference cell configuration information may include L1 measurement resource settings for continuous LTM.

[0192] The reference cell configuration information transmitted by the source base station CU (603) to each candidate cell (604, 605) may be a common configuration that can be applied to multiple target candidate cells in order to reduce signaling overhead when target candidate cells provide configuration information for LTM. Additionally, the common configuration information may include at least one of measurement configuration, bearer configuration, or configurations set at the CellGroup level if the cells belong to the same CellGroup (e.g., MAC-CellGroupConfig, RLC bearer configuration, SCell configuration, etc.). Alternatively, if the source base station CU (603) has a procedure to roughly know or know the configuration information for each candidate cell (604, 605, 607), the reference cell configuration may be determined through a separate procedure to obtain the reference cell configuration information. The purpose of the source base station CU (603) transmitting the reference cell settings to each candidate cell (604, 605, 607) may be to allow the delta configuration (a method of configuring a complete or perfect configuration by applying settings added on top of the reference cell settings, or a method of configuring a complete configuration by applying settings over the reference cell settings in the target cell) to the source base station CU (603). The delta configuration may then be transmitted to the terminal as is, thereby reducing the signaling of RRC messages transmitted to the terminal. Alternatively, the delta configuration may be omitted when the source base station CU (603) transmits the reference cell settings to each candidate cell (604, 605, 607). In this case, the source base station CU (603) may provide the candidate cell settings as a complete RRC configuration.

[0193] In step 640, the source cell (602) can receive and transmit to the terminal an RRC message generated by the base station CU (603) based on configuration information received from each candidate cell. The transmitted RRC message may be a message containing configuration information for surrounding candidate cells to which L1 / L2-based handover (LTM) is applied. The RRC message may include detailed configurations for the L1 measurement report based on LTM events proposed in this disclosure. Specific details are described below in FIG. 7.

[0194] In step 645, the terminal (601) that receives the corresponding RRC message may perform a procedure to decode and process the RRC message. The processing may include ASN.1 (abstract syntax notation one) decoding of the received message, validation, and methods for storing and managing the configuration content. Additionally, the terminal (601) may store the LTM configuration information for each candidate cell decoded in this step as complete configuration information in the terminal's buffer (memory). Additionally, the terminal (601) may also store and manage the received reference cell configuration information in the terminal's buffer (memory). The reference cell configuration information may be omitted from the RRC message (or configuration information for each LTM candidate cell) in step 640. In this case, the terminal (601) recognizes that there is no reference cell configuration information, determines the configuration information for the received LTM target candidate cells as complete or complete configuration information (hereinafter referred to as complete configuration information), and stores it. At this time, the reference cell configuration information may not be stored separately (operates as empty). For example, a delta configuration may not be applied. Additionally, the above message may convey L1 measurement resources and reporting setting information for continuous LTM. Specific settings refer to the descriptions above in this disclosure.

[0195] Although the present disclosure primarily deals with event-based L1 channel measurement and reporting being directed, other forms of L1 channel measurement reporting may be set separately, and the terminal (601) may perform other forms of L1 channel measurement reporting. Although omitted in FIGS. 6a and 6b, existing L1 measurement and reporting procedures may be added. Based on this, in step 650, the source base station (602) may direct the terminal (601) to a TCI state to direct the optimal beam used in the corresponding serving cell as a unified TCI state activation MAC CE. Upon receiving the TCI state, the terminal (601) may perform an event-based L1 resource measurement and evaluation step considered by the terminal (601) in step 650, and if the execution conditions for a specific event are satisfied, the terminal may transmit an L1 measurement report through an event-based L1 measurement MAC CE in step 660. The source base station (602) that receives the L1 measurement report may instruct the terminal (601) to change the LTM cell in step 665 by referring to the L1 measurement value. In step 665, MAC CE including a handover indicator may be used for L1 / L2 signaling. If it is necessary to perform RACH-less LTM before step 665, a procedure for obtaining a TA for the corresponding target cell may be added. The source cell (602) may make the final decision on the LTM and may not transmit the L1 measurement value to the base station (603). At this time, the source cell (602) may decide on the handover itself based on measurement criteria (e.g., threshold value and measurement value range) for making a handover decision for each candidate surrounding cell received from the previous base station, and may transmit the L1 / L2 signaling to the terminal (601). Afterwards, the source cell (602) may transmit the LTM decision information to the CU.When an L1 / L2 handover instruction is transmitted to the terminal (601), the terminal (601) may start the handover procedure in step 670 and start a timer for the L1 / L2 handover. The timer may be a newly set timer for the LTM, or an existing T304 timer may be reused. In step 675, the terminal (601) may apply settings for the target cell to which the L1 / L2 handover is applied. For example, the terminal (601) may replace the current settings with complete setting information for the instructed LTM target cell that was previously stored in the terminal (601). This may be one of the LTM candidate surrounding cell settings received in advance in step 640 and a setting stored in the terminal. Depending on the settings applied in step 680, the terminal (601) may perform random access for the corresponding target cell if random access is required. Additionally, if random access is not instructed or is not required (e.g., if uplink synchronization has already been performed or set), the random access procedure may be omitted.

[0196] In step 685, the terminal (601) can perform a handover completion procedure with the target cell. The handover completion procedure may be a handover completion procedure for the LTM. The handover completion procedure may be a process of delivering an RRCReconfiugrationComplete message to an RRC message which is a setting of the target cell, and the actual handover completion may be determined by the end of the random access process.

[0197] In step 690, the target cell (DU, 604) that receives the handover completion message can transmit the received message to the base station CU (603) (695). At this time, the target cell (DU, 604) can transmit the handover completion message received through the F1 interface as is, or process the message based on the received information and transmit it. Afterwards, the base station CU (603) can transmit information about the handover completion to the source cell (602) and instruct it to release the terminal context.

[0198] Additionally, as described in step 697, embodiments of the present disclosure support subsequent LTM operations. A subsequent LTM operation may mean that the LTM configuration information (e.g., configuration for target candidate cells and reference cell configuration information) received by the terminal (601) in step 640 is stored in the terminal (601) as is, and the terminal (601) continues to perform the LTM procedure unless the LTM configuration information is changed, released, or added through a separate RRC configuration. If it is necessary to update the reference cell configuration information, new RRC configuration information can be transmitted to the terminal (601) to perform the LTM procedure. Accordingly, the procedures described in FIGS. 6a and 6b above can be triggered and performed again.

[0199] In summary, if the terminal (601) receives reference cell setting information in step 640, it stores it in the terminal buffer so that, unless there is an update to a separate setting, it can continue to use the setting as reference cell setting information even after LTM execution (step 670) (for example, reference cell setting and LTM candidate setting values ​​stored in consecutive LTMs can be applied). Additionally, if the terminal (601) does not receive reference cell setting information while in an RRC connection state in step 640, the terminal (601) may store the reference cell setting empty according to the terminal operation option described above, or store the setting information for the source cell (primary cell, PCell) that received the LTM setting information as reference cell setting information.

[0200] FIG. 7 illustrates the overall terminal operation for performing an event-based L1 measurement report to perform an L1 / L2-based handover in a wireless communication system according to various embodiments of the present disclosure. In the terminal operation of the present disclosure, an internal operation for triggering an event for the event-based L1 measurement report (e.g., a beam-based TimeToTrigger method or a TTT method) and information included in the actual event-based L1 measurement report are proposed.

[0201] In step 705, a terminal in a connected state (e.g., RRC connected state) may receive configuration information from neighboring cells and LTM-related settings that are applied after L1 / L2-based movement is instructed via an RRC reset message from a serving cell. The configuration method and related description may be applied identically or similarly to the descriptions in FIG. 6a and FIG. 6b described above. The present disclosure is characterized by the terminal receiving L1 event-based measurement reporting settings for LTM operation, and the invention below includes detailed operations and related settings. The TTT method may be a method in which, when a specific beam within an LTM candidate cell satisfying an LTM event for an L1 measurement value satisfies a threshold, if the beam satisfying the threshold continues to satisfy the condition for a specific time, the event is finally triggered so that the terminal performs a triggered event measurement report. For reference, the TTT function may be configured per L1 event and may be configured as a specific time value. In addition, although omitted prior to the above RRC configuration information, the terminal has received basic RRC configuration from the base station and can perform the operation of reporting layer 3 measurement values ​​for surrounding cells. The configuration information in the LTM candidate cell applied after the L1 / L2-based movement received in step 705 is transmitted with a delta configuration applied based on the configuration of a single reference cell.

[0202] In step 710, the terminal can decode the settings for the received LTM candidate cells based on the settings of the reference cell and store and manage the complete settings that are actually applied (e.g., the operation of saving a delta-configured setting based on the reference cell as a complete configuration by referring to the reference cell settings) in a separate buffer and list. Alternatively, the terminal may not decode the received settings based on the reference cell and store and manage the settings that are actually applied, but may store and manage the received RRC settings as they are in the buffer. As described above in FIGS. 6a and 6b, if the reference cell settings are omitted when received, the terminal can identify that there is no reference cell setting information, and can determine and store the setting information for the received LTM target candidate cells as complete setting information. In particular, in the present disclosure, LTM-related settings may be provided in the corresponding step, and specifically, the LTM-related settings may include candidate cell settings for LTM and settings for L1 resources that require measurement. The terminal can decode the settings (e.g., LTM-related settings) and store and manage them in the terminal buffer.

[0203] In step 715, the terminal may receive instructions from the base station via MAC CE regarding the TCI state applied to the source cell. Among the beams indicated by MAC CE, the source cell beam used for the actual event-based L1 measurement evaluation may be an active beam indicated via MAC CE or DCI (downlink control information). For example, it may be a beam for receiving PDCCH or a beam for receiving PDSCH indicated by the scheduling DCI. The terminal may determine the source cell beam according to the instructions from the base station and use the determined beam as a reference source cell beam for evaluating each event for subsequent L1 event-based measurement reporting.

[0204] In step 720, the terminal can perform an L1 measurement configured with an SSB or CSI-RS resource associated with a cell surrounding an LTM candidate while maintaining a connection with the cell. For example, the terminal can measure L1 measurement resources for LTM candidate cells configured to be measured (e.g., multiple CSI measurement resources configured within a set of CSI resources for the candidate cell) and check whether the conditions of a configured LTM event are satisfied by comparing the measurement results with the current beam of the serving cell. The LTM event here may be one of Event LTM2, Event LTM3, Event LTM4, or Event LTM5 described in FIGS. 6a and 6b. For example, if Event LTM3 (Beam of candidate cell becomes amount of offset better than beam of serving cell) is configured, if any beam within the configured CSI resource set measures a value that is better by a preset offset compared to the designated beam of the current source cell (e.g., a reference beam for LTM event-based measurement), the terminal can check whether to initiate TTT in step 725 and maintain the operation until the TTT expires. Here, detailed operations, such as resetting the TTT value based on the beam-based measurement value, can be performed in the following manner. Of course, it is not limited to the examples below.

[0205] - Beam-based TTT operation method

[0206] -- The terminal can perform beam-based L1 measurements and determine TTT operations based only on a specific beam (e.g., the beam that satisfied the first LTM event).

[0207] -- The terminal can start the TTT from the beam that first satisfies a specific LTM event within the CSI resource set, and reset the TTT if the beam does not satisfy the LTM event condition.

[0208] -- The terminal may reset the TTT if the beam of the current source cell changes. Alternatively, the terminal may continue to apply a cell beam that satisfies the TTT operation if such a beam exists, even if the beam of the source cell changes. For example, the terminal may continue to use the beam of the current source cell even if the beam of the source cell changes, until reporting for a single initiated LTM event is complete.

[0209] - Distinction regarding satisfaction of the Leaving condition

[0210] -- For beam-based L1 measurement events, even when the leaving condition is satisfied, the event is triggered to perform a TTT operation, and subsequent L1 measurement reporting can be supported.

[0211] For the same L1-based measurement event, it may be necessary to distinguish whether the entering condition or the leaving condition has been satisfied.

[0212] --- Method 1: Event-based L1 measurement reporting. Include an indicator within the MAC CE that indicates the measurement report is for satisfying an entering or leaving condition.

[0213] ----- Method 2: Event-based L1 measurement reporting. An indicator within the MAC CE may not be included to indicate that the measurement report satisfies the entering condition or the leaving condition. In this case, whether the reported information satisfies the entering condition or the leaving condition can be implicitly inferred through the measurement report ID indicated within the same MAC CE and / or the beam information of the source cell for the corresponding event.

[0214] --- Method 3: Introduce a procedure to manage L1 event-based measurement-related variables at the MAC layer

[0215] A. Beam and cell-related variables satisfying LTM event-based measurement

[0216] i. maxReportBeamsLTM: The maximum number of beams included in a specific event reported within the event-based L1 measurement report MAC CE

[0217] ii. includeBeamsNoMetCondition: Instructs reporting on beams that do not satisfy a specific event reported within the event-based L1 measurement report MAC CE. For example, if maxReportBeamsLTM is 3 and includeBeamsNoMetCondition is specified, and there are 2 beams that satisfy the event, the terminal may report the 2 beams along with the best measured beam that did not satisfy the event condition. Alternatively, the above maxReportBeamsLTM may be configured to distinguish between beams that satisfy the event and beams that do not satisfy the event but must be reported.

[0218] iii. beamsTriggeredListLTM: A list storing beams that satisfy an event of a specific event-based L1 measurement report. The terminal stores the corresponding beam when a specific beam-based event is satisfied.

[0219] iv. cellsTriggeredListLTM: A list storing the cells to which beams that satisfied the event of a specific event-based L1 measurement report by the terminal belong.

[0220] v. beamsMetLeavingCondLTM: A list storing beams that satisfy the leaving condition for specific event-based L1 measurement reports.

[0221] vi. cellsMetLeavingCondLTM: A list storing the cells to which the beam belongs that satisfies the leaving condition for an event in a terminal's L1 measurement report based on a specific event.

[0222] B. Introduce an indicator within the event-based L1 measurement report MAC CE to indicate whether the report satisfies the first entering condition.

[0223] C. Introduce an indicator within the event-based L1 measurement report MAC CE to indicate whether the report satisfies the Leaving condition.

[0224] D. Related Actions

[0225] i. If reportType is set to eventTriggeredLTM and the entering condition is satisfied by satisfying timeToTrigerLTM for one or more beams (or cells) for a specific event, the terminal can save the corresponding beam or cell to beamsTriggeredListLTM and cellsTriggeredListLTM.

[0226] (If the reportType set to eventTriggeredLTM and the entering condition is fulfilled for one or more beams (or cells) during timeToTriggerLTM, the UE includes the concerned beams in the beamsTriggeredListLTM and cellsTriggeredListLTM.)

[0227] ii. If reportType is set to eventTriggeredLTM and the leaving condition is satisfied by satisfying timeToTrigerLTM for one or more beams (or cells) for a specific event, the terminal may remove the corresponding beam or cell from beamsTriggeredListLTM and cellsTriggeredListLTM. Instead, the terminal may store the corresponding beam and cell information in beamsMetLeavingCondLTM and cellsMetLeavingCondLTM.

[0228] (If the reportType set to eventTriggeredLTM and the leaving condition is fulfilled for one or more beams (or cells) during timeToTriggerLTM, the UE removes the concerned beams in the beamsTriggeredListLTM and cellsTriggeredListLTM. UE stores the concerned beams in the cellsMetLeavingCondLTM and cellsMetLeavingCondLTM.)

[0229] iii. In event-based LTM MAC CE, the terminal can report the number of surrounding beams present in beamsTriggeredListLTM and cellsTriggeredListLTM in order of good beams according to the base station setting (maxReportBeamsLTM).

[0230] (In the LTM MR(measurement report), the UE sets the best neighboring beams (among the beams in the beamsTriggeredListLTM or cellsTriggeredListLTM) up to maxReportBeamsLTM configured by NW)

[0231] In step 725, the terminal may apply detailed actions (e.g., L1 resource measurement and evaluation) and detailed TTT actions for LTM events. Additionally, if the TTT initiated for a specific LTM event expires, the terminal may generate an LTM event-based measurement report MAC CE in step 730. The MAC CE may include at least one of the following information related to measurement values. Of course, it is not limited to the examples below.

[0232] - Event-satisfying beam information: Information about the SSB or CSI-RS resources to be reported (e.g., index).

[0233] - Measured beam value: L1-RSRP (reference signals received power) or SINR (signal to interference plus noise ratio) (up to RAN1) value

[0234] -- Regarding the RSRP information, the initial best beam may report the total RSRP value, and other beams reported thereafter may report the differential RSRP values ​​that differ from that best beam.

[0235] - Triggered LTM measurement event information: For example, ReportConfigID

[0236] - Source cell beam information (sPCell beam information: may include the beam used for LTM events or the best beam)

[0237] - The indicator that satisfies the first entering condition

[0238] - Indicator of whether the Leaving condition is satisfied

[0239] In addition, regarding the above measurement information, the following method is proposed depending on whether only beams related to a single event or beams related to multiple events are included within the MAC CE. Generally, a base station sets multiple LTM measurement events for a terminal, and the terminal can simultaneously measure and evaluate these events according to the settings. Accordingly, there may be cases where the terminal satisfies multiple events simultaneously, and a method is described regarding which MAC CE to report the measurement value for such event satisfaction.

[0240] - Option 1: Report only the beams included in a single event where the terminal triggered an LTM event. For example, a single MAC CE contains only one report ID.

[0241] - Option 2: Report only the beams included in multiple events where the terminal triggered an LTM event. For example, a single MAC CE includes multiple report IDs and their associated beam reporting information.

[0242] -- In this case, an indicator may be added to indicate that multiple events are included within the corresponding MAC CE.

[0243] -- When Truncated MAC CE is used, reports can be separated by the corresponding report ID.

[0244] In step 735, the terminal can transmit the event-based measurement report MAC CE generated in step (730) to the base station. The MAC CE may include the information described above. The serving cell can determine whether to change the terminal's beam and hand over based on the received measurement results, and if it is determined that a change to a specific beam of a surrounding cell is necessary rather than a specific beam of the serving cell, it can instruct the terminal to hand over and change the beam through L1 / L2 signaling.

[0245] If a terminal reports a MAC CE for an LTM event at that stage, and since such MAC CE reports are continuously measured and evaluated, the terminal may continuously report measurement and result values ​​via MAC CE for other LTM events or the same event in the absence of separate management. Accordingly, a method is proposed to prevent the terminal from continuously reporting event-based L1 measurements (MAC CE transmission).

[0246] - Introduction of a prohibit timer for event-based LTM measurement reporting MAC CE

[0247] -- Method 1: Introduce a single timer applied to the all-event-based LTM MAC CE

[0248] -- Method 2: Individual prohibit timers are set for each event, and the terminal applies the timer only to the MAC CE reported in association with the corresponding report ID.

[0249] - Periodically perform measurement reporting for triggered events (e.g., transmit event-based LTM measurement reports MAC CE)

[0250] -- Provides repetition period and number of repetitions based on base station settings

[0251] --- Method 1: Provide a single setting per terminal. For example, measurement reports belonging to all report IDs are reported periodically a set number of times when an event is satisfied, according to the setting.

[0252] --- Method 2: Measurement reports per event (e.g., by report ID) are reported periodically a set number of times when the event is satisfied, according to the settings.

[0253] -- Method to acquire UL resources in the case of repeated transmission

[0254] --- Method 1: For each recurring cycle report, the terminal requests an uplink (UL) grant from the base station (scheduling request and buffer status report (BSR)), and after receiving the UL grant, transmits an event-based LTM measurement report MAC CE.

[0255] --- Method 2: The base station identifies that the initial transmitted event-based LTM measurement report request (dedicated SR) is a recurring report and periodically provides a UL grant to meet the corresponding conditions (omitting the terminal's separate SR and BSR procedures).

[0256] -- Dedicated SR assignment associated with event-based LTM measurement reporting MAC CE

[0257] --- Associate the SR ID with all event-based MRs (measurement reports)

[0258] --- Configure SR IDs associating them with specific events in event-based MRs (e.g., configure SRs by report ID)

[0259] -- Terminal action following the reported event result value according to the setting (e.g., periodic reporting or one-time reporting)

[0260] --- Method 1: After the terminal transmits an event-based LTM measurement report MAC CE according to the base station settings, the terminal clears the settings for the triggered event and no longer performs related actions. This is because if the terminal performs a measurement report for a specific event, the base station will perform the related action, and it can be considered meaningless to perform measurements on the same measurement resource. Even for the same event, the entering condition and the leaving condition can be determined differently.

[0261] --- Method 2: After the terminal transmits an event-based LTM measurement report MAC CE according to the base station settings, the terminal continues to perform related actions according to the settings for the corresponding triggered event (after a specific time has elapsed; timer setting).

[0262] In step 740, if a TTT reset occurs for a specific triggered LTM event or if the event-based LTM measurement reporting event conditions are no longer satisfied, the terminal can continue to perform the corresponding L1 measurement and evaluation.

[0263] FIG. 8 is a drawing illustrating base station operation according to various embodiments of the present disclosure.

[0264] In step 805, the base station can receive L3 measurement reports from the terminal. Based on the terminal's measurements regarding surrounding frequencies and cells, the base station can determine whether the terminal requires a handover and which cells are candidate cells for the handover.

[0265] In step 810, the base station may request configuration information for L1 / L2-based handover from surrounding cells and receive responses from those cells. In this step, the base station may transmit configuration information for the current source cell and reference cell configuration information together to the surrounding cells. The base station may also receive RRC configuration information, to which delta configuration is applied based on the reference cell configuration information, from surrounding cells and LTM candidate cells. Additionally, in this step, inter-node coordination for L1 measurement resources and reporting settings proposed in this disclosure may be performed. The procedure described in FIGS. 6a and 6b may be included in this step, and in particular, may include determining L1 measurement resources and reporting settings within intra-CU and inter-CU. Although omitted in FIG. 8, settings related to L3 measurement settings and basic RRC settings may be provided prior to this step (810).

[0266] In step 815, the base station may transmit an RRC configuration message generated including the surrounding cell configuration information and L1 measurement resource / reporting settings received in step 810 to a terminal in a connected state (e.g., RRC connected state). For example, the base station may transmit to the terminal configuration information from a surrounding cell that is applied after L1 / L2-based movement is instructed via an RRC reset message from a serving cell. Specific configuration methods and details may be applied as described in FIGS. 6a, 6b, and 7.

[0267] In step 820, the base station may instruct the terminal to report L1 measurements in various ways via RRC or L1 / L2 signaling, depending on the L1 measurements and reports for which configuration and triggering are desired. Specific methods may follow the embodiments described above. Reports regarding L1 and L3 measurement values ​​may be received from the terminal. In this disclosure, a case in which an event-based L1 measurement report MAC CE is received from the terminal in that step may be considered. In this case, the L1 measurement value may be related to a non-serving cell that supports L1 / L2-based mobility. The serving cell may determine whether to change the terminal's beam and whether to hand over based on the received measurement results. If the serving cell determines that a change to a specific beam of a non-serving cell is necessary rather than a specific beam of the serving cell, it may instruct the terminal to perform an LTM handover via L1 / L2 signaling in step 825. The above L1 / L2 signaling may be a MAC CE and may include information instructing a change to a specific beam of a non-serving cell. In addition, existing handovers via RRC messages can also be independently directed at that stage. This can occur because the base station and the serving cell independently determine the LTM and layer 3 handover.

[0268] In step 835, when the base station receives a handover completion message (830) from the terminal, it can confirm that the LTM operation has been successfully completed. Accordingly, the base station can notify the previous source cell of the handover completion and request the release of the terminal context. Additionally, if the base station receives a handover failure report message containing information that the handover failed, it may receive a message indicating that the terminal attempted to reconnect to the cell after the handover failure. The handover failure report message may be a UEInformationResponse or another uplink RRC message. Furthermore, the terminal may report the handover failure via a new MAC CE or uplink control signal (UCI; uplink control information). The information included in the handover failure report message may include at least one of the following information. Of course, it is not limited to the examples below.

[0269] - An indicator that the handover failed due to an LTM failure

[0270] - Target cell information where LTM attempt failed: LTM cell configuration index or actual cell index (PCI; Physical Cell Index) information

[0271] The source base station can know that the LTM attempt failed and fell back to the cell through the handover failure message report.

[0272] FIG. 9 is a block diagram illustrating the internal structure of a terminal in a wireless communication system according to various embodiments of the present disclosure.

[0273] Referring to FIG. 9, the terminal includes an RF (Radio Frequency) processing unit (910), a baseband processing unit (920), a storage unit (930), and a control unit (940).

[0274] The RF processing unit (910) performs functions for transmitting and / or receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (910) up-converts the baseband signal provided by the baseband processing unit (920) into an RF band signal, transmits it through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (910) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC (digital to analog converter), an ADC (analog to digital converter), etc. Although only one antenna is shown in the drawing, the terminal may be equipped with multiple antennas. In addition, the RF processing unit (910) may include multiple RF chains. Furthermore, the RF processing unit (910) may perform beamforming. For the above beamforming, the RF processing unit (910) can adjust the phase and magnitude of each of the signals transmitted and / or received through a plurality of antennas or antenna elements. In addition, the RF processing unit can perform MIMO and can receive multiple layers when performing MIMO operation.

[0275] The baseband processing unit (920) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (920) generates complex symbols by encoding and modulating the transmitted bit sequence. Additionally, when receiving data, the baseband processing unit (920) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (910). For example, in the case of following the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit (920) generates complex symbols by encoding and modulating the transmitted bit sequence, maps the complex symbols to subcarriers, and then constructs OFDM symbols through IFFT (inverse fast Fourier transform) operation and CP (cyclic prefix) insertion. Additionally, upon receiving data, the baseband processing unit (920) divides the baseband signal provided by the RF processing unit (910) into OFDM symbol units, restores the signals mapped to subcarriers through a fast Fourier transform (FFT) operation, and then restores the received bit sequence through demodulation and decoding.

[0276] The baseband processing unit (920) and the RF processing unit (910) transmit and receive signals as described above. Accordingly, the baseband processing unit (920) and the RF processing unit (910) may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, or a communication unit. Furthermore, at least one of the baseband processing unit (920) and the RF processing unit (910) may include a plurality of communication modules to support a plurality of different wireless access technologies. Additionally, at least one of the baseband processing unit (920) and the RF processing unit (910) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include wireless LAN (e.g., IEEE 802.11), cellular network (e.g., LTE), etc. In addition, the above different frequency bands may include super high frequency (SHF) bands (e.g., 2 NRHz, NRHz) and millimeter wave (e.g., 60 GHz) bands.

[0277] The storage unit (930) stores data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the storage unit (930) can store information related to a second connection node that performs wireless communication using a second wireless connection technology. Additionally, the storage unit (930) provides the stored data upon the request of the control unit (940).

[0278] The control unit (940) controls the overall operations of the terminal. For example, the control unit (940) transmits and receives signals through the baseband processing unit (920) and the RF processing unit (910). Additionally, the control unit (940) writes and reads data to and from the storage unit (940). To this end, the control unit (940) may include at least one processor. For example, the control unit (940) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as applications. Additionally, according to one embodiment of the present disclosure, the control unit (940) may include a multiple connection processing unit (942) configured to process a process operating in a multiple connection mode.

[0279] FIG. 10 is a block diagram showing the configuration of a base station in a wireless communication system according to various embodiments of the present disclosure.

[0280] Referring to FIG. 10, the base station is configured to include an RF processing unit (1010), a baseband processing unit (1020), a backhaul communication unit (1030), a storage unit (1040), and a control unit (1050).

[0281] The RF processing unit (1010) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (1010) upconverts the baseband signal provided by the baseband processing unit (1020) into an RF band signal and transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (1010) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. Although only one antenna is shown in the drawing, the first connection node may be equipped with multiple antennas. In addition, the RF processing unit (1010) may include multiple RF chains. Furthermore, the RF processing unit (1010) may perform beamforming. For beamforming, the RF processing unit (1010) may adjust the phase and magnitude of each of the signals transmitted and received through multiple antennas or antenna elements. The above RF processing unit can perform down-to-down MIMO operation by transmitting one or more layers.

[0282] The baseband processing unit (1020) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the first wireless access technology. For example, when transmitting data, the baseband processing unit (1020) generates complex symbols by encoding and modulating the transmitted bit sequence. Additionally, when receiving data, the baseband processing unit (1020) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (1010). For example, in the case of following the OFDM method, when transmitting data, the baseband processing unit (1020) generates complex symbols by encoding and modulating the transmitted bit sequence, maps the complex symbols to subcarriers, and then constructs OFDM symbols through IFFT operation and CP insertion. Additionally, upon receiving data, the baseband processing unit (1020) divides the baseband signal provided by the RF processing unit (1010) into OFDM symbol units, restores the signals mapped to subcarriers through FFT operations, and then restores the received bit sequence through demodulation and decoding. The baseband processing unit (1020) and the RF processing unit (1010) transmit and receive signals as described above. Accordingly, the baseband processing unit (1020) and the RF processing unit (1010) may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, a communication unit, or a wireless communication unit.

[0283] The backhaul communication unit (1030) provides an interface for communicating with other nodes within the network. That is, the backhaul communication unit (1030) converts a bit sequence transmitted from the main base station to another node, e.g., an auxiliary base station, a core network, etc., into a physical signal, and converts a physical signal received from the other node into a bit sequence.

[0284] The storage unit (1040) stores data such as basic programs, application programs, and configuration information for the operation of the main station. In particular, the storage unit (1040) can store information regarding bearers assigned to connected terminals, measurement results reported from connected terminals, etc. Additionally, the storage unit (1040) can store information that serves as a criterion for determining whether to provide multiple connections to the terminal or to disconnect them. Furthermore, the storage unit (1040) provides the stored data in response to a request from the control unit (1050).

[0285] The control unit (1050) controls the overall operations of the main station. For example, the control unit (1050) transmits and receives signals through the baseband processing unit (1020) and the RF processing unit (1010) or through the backhaul communication unit (1030). Additionally, the control unit (1050) writes and reads data to and from the storage unit (1040). To this end, the control unit (850) may include at least one processor. Additionally, according to one embodiment of the present disclosure, the control unit (1050) may include a multiple connection processing unit (1052) configured to process a process operating in a multiple connection mode.

[0286] Methods according to the embodiments described in the claims or specification of the present invention may be implemented in the form of hardware, software, or a combination of hardware and software.

[0287] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present invention.

[0288] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), magnetic disc storage devices, CD-ROM (Compact Disc-ROM), Digital Versatile Discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0289] Additionally, the program may be stored on an attachable storage device accessible via a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present invention through an external port. Additionally, a separate storage device on the communication network may be connected to a device performing an embodiment of the present invention.

[0290] In the specific embodiments of the present invention described above, the components included in the invention are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present invention is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed in the singular form, or even if a component is expressed in the singular form, it may be composed in the plural form.

[0291] Meanwhile, although specific embodiments have been described in the detailed description of the present invention, it is understood that various modifications are possible within the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

[0292] In the drawings describing the embodiments of the present disclosure, the order of description does not necessarily correspond to the order of execution, and the order of execution may be changed or executed in parallel. Additionally, the drawings describing the embodiments of the present disclosure may omit some components and include only some components to the extent that the essence of the present disclosure is not impaired.

[0293] The embodiments of the present disclosure may be practiced by combining some or all of the contents included in each embodiment to the extent that the essence of the present disclosure is not impaired.

[0294] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other variations based on the technical concept of the present disclosure are possible in addition to the embodiments disclosed herein.

Claims

1. A method performed by a terminal of a wireless communication system, A step of receiving configuration information regarding an event trigger L1 (layer 1) measurement report for a beam from a base station; Based on the above setting information, a step of identifying at least one beam that satisfies the entry condition for an LTM (L1 / L2 triggered mobility) event during TTT (time to trigger); A step of generating a MAC (medium access control) CE (control element) containing information about at least one beam; and A method comprising the step of transmitting the MAC CE to the base station.

2. In paragraph 1, the above method is: A method further comprising the step of identifying at least one beam satisfying the deviation condition for the LTM event during the TTT based on the above setting information.

3. In paragraph 1, the above method is: The MAC CE includes at least one of a reporting identifier, a type of beam included in the event-triggered L1 measurement report, a reference signal resource indicator (RSRI) of the beam, or a reference signal received power (RSRP) for the beam. The at least one beam satisfying the entry condition for the LTM event during the above TTT is associated with the reporting identifier, and A method wherein the RSRP comprises at least one of an RSRP for a first beam, a differential RSRP for the RSRP for the first beam, or an RSRP for the current beam of a serving cell.

4. In Paragraph 1, A method comprising at least one of the above setting information, which includes information regarding the maximum number of reported beams, or information indicating whether to report beams that do not satisfy the entry condition for the LTM event during the TTT.

5. In Paragraph 2, The at least one beam satisfying the entry condition for the LTM event during the above TTT is included in the first list for the event trigger L1 measurement report, and A method in which at least one beam satisfying the deviation condition for the LTM event during the above TTT is included in a second list for the event trigger L1 measurement report.

6. In Paragraph 1, A method in which, when the beam of the serving cell is changed and the above entry condition is satisfied, the TTT does not restart.

7. In Paragraph 1, A method in which the above MAC CE is transmitted based on a prohibition timer included in the above setting information.

8. Regarding the terminal: At least one transceiver; At least one processor communicatively coupled to the above at least one transceiver; and It includes at least one memory that is communicationally coupled to the above at least one processor and stores instructions, and The above instructions are executed individually or in any combination by the above at least one processor, so that the terminal: Receive configuration information regarding an event trigger L1 (layer 1) measurement report for a beam from the base station, and Based on the above configuration information, identify at least one beam that satisfies the entry condition for an LTM (L1 / L2 triggered mobility) event during TTT (time to trigger), and Generate a MAC (medium access control) CE (control element) containing information for at least one beam, and A terminal that transmits the MAC CE to the above base station.

9. In paragraph 8, the above commands are the terminal: A terminal that identifies at least one beam satisfying the break-in condition for the LTM event during the TTT based on the above setting information.

10. In Paragraph 8, The MAC CE includes at least one of a reporting identifier, a type of beam included in the event-triggered L1 measurement report, a reference signal resource indicator (RSRI) of the beam, or a reference signal received power (RSRP) for the beam. The at least one beam satisfying the entry condition for the LTM event during the above TTT is associated with the reporting identifier, and A terminal in which the above RSRP comprises at least one of an RSRP for a first beam, a differential RSRP for the RSRP for the first beam, or an RSRP for the current beam of a serving cell.

11. In Paragraph 8, A terminal comprising at least one of the above setting information, which includes information regarding the maximum number of reported beams, or information indicating whether to report beams that do not satisfy the entry condition for the LTM event during the TTT.

12. In Paragraph 9, The at least one beam satisfying the entry condition for the LTM event during the above TTT is included in the first list for the event trigger L1 measurement report, and A terminal in which at least one beam satisfying the break-in condition for the LTM event during the above TTT is included in the second list for the event trigger L1 measurement report.

13. In Paragraph 8, A terminal in which, when the beam of the serving cell changes and the above entry condition is satisfied, the TTT does not restart.

14. In Paragraph 8, A terminal in which the above MAC CE is transmitted based on a prohibition timer included in the above setting information.

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