Method and apparatus for performing event-based layer 1 measurement reporting in next-generation mobile communication system

Abstract

In a wireless communication system, a UE receives, from a base station, an RRC message including measurement resource configuration information for an LTM candidate cell and report configuration information related to LTM measurement reporting, wherein the report configuration information is for configuring event trigger-based measurement reporting and includes information about a TTT value related to an event and the number of beams for which measurement results are to be reported. The present invention relates to a method and apparatus for performing event-based L1 measurement reporting for L1 / L2-based handover, wherein the UE measures a plurality of beams of a candidate cell on the basis of the measurement resource configuration information, and when a first beam satisfying an event condition for a time corresponding to a TTT is identified among the plurality of beams, transmits an L1 measurement report MAC CE to the base station, and the L1 measurement report MAC CE includes information about beams corresponding to the number of beams and has recorded thereon a resource index and a measurement value related to a reference signal of the first beam.

Description

Method and apparatus for performing event-based Layer 1 measurement reporting in a next-generation mobile communication system

[0001] The present disclosure relates to a method and apparatus for performing event-based L1 measurement reporting for L1 / L2-based handover.

[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 such as beamforming and Massive MIMO to mitigate path loss and increase transmission distance in ultra-high frequency bands, support for various numerologies (such as the operation of multiple subcarrier spacings) and dynamic operation of slot formats for the efficient utilization of ultra-high frequency resources, initial access techniques to support multi-beam transmission and broadband, definition and operation of Band-Width Parts (BWP), Low Density Parity Check (LDPC) codes for high-volume data transmission, new channel coding methods such as Polar Codes for the reliable transmission of control information, and L2 pre-processing (L2 Standardization has been carried out for pre-processing, network slicing which provides a dedicated network specialized for specific services, and other methods.

[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 to comply with 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] Furthermore, the advancement of these 5G mobile communication systems encompasses multi-antenna transmission technologies such as new waveforms, Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas to guarantee coverage in the terahertz band of 6G mobile communication technology; metamaterial-based lenses and antennas; high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM); and Reconfigurable Intelligent Surface (RIS) technology to improve terahertz band signal coverage; as well as full-duplex technology for enhancing frequency efficiency and system networks in 6G mobile communication technology; AI-based communication technologies that realize system optimization by utilizing satellites and Artificial Intelligence (AI) from the design stage and internalizing end-to-end AI support functions; and the realization of services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources. It could serve as a foundation for the development of next-generation distributed computing technologies.

[0008] Layer 1 / Layer 2 (Layer 1 / Layer 2) triggered mobility (LTM; L1 / L2-based mobility) can be determined based on Layer 1-based measurements by the terminal. That is, to support LTM, methods are required to set L1 measurement information for surrounding candidate cells for LTM, and methods for the terminal to perform measurements and reporting based on the set L1 measurement information. For example, in the case of event-based Layer 1 measurement reporting, since it is based on beam-based signal strength comparison and subsequent beam reporting, specific procedures for setting need to be defined.

[0009] Accordingly, one objective of the present disclosure is to propose a detailed operation for setting up an event-based Layer 1 measurement report for LTM.

[0010] More specifically, one objective of the present disclosure is to define a procedure for reporting information related to beam measurements and information to be reported for LTM event-based Layer 1 measurement reporting.

[0011] A method of a terminal in a wireless communication system according to an example of the present disclosure for solving the above-mentioned problems comprises: receiving a radio resource control (RRC) message from a base station that includes measurement resource setting information for an LTM (layer 1 / layer 2 triggered mobility) candidate cell and report setting information regarding an LTM measurement report - wherein the report setting information includes setting an event-trigger-based measurement report, information regarding a time to trigger (TTT) related to the event, and information regarding the number of beams to be reported for measurement results -; measuring a plurality of beams for the candidate cell based on the measurement resource setting information; and, when a first beam among the plurality of beams is identified that satisfies the conditions of the event during a time corresponding to the TTT, transmitting an L1 measurement report MAC (medium access control) CE (control element) to the base station based on the report setting information, wherein the L1 measurement report MAC CE includes information regarding beams corresponding to the number of beams, and the information regarding the beams may include a resource index related to a reference signal of the first beam and a measurement value of the first beam.

[0012] In addition, a method of a base station in a wireless communication system according to one example of the present disclosure comprises the step of transmitting a radio resource control (RRC) message to a terminal, the message including measurement resource setting information for a layer 1 / layer 2 triggered mobility (LTM) candidate cell and report setting information regarding an LTM measurement report, wherein the report setting information includes setting an event trigger-based report, information regarding a time to trigger (TTT) related to the event, and information regarding the number of beams to be reported for measurement results; and the step of receiving a medium access control (MAC) control element (CE) from the terminal based on the report setting information, wherein the L1 measurement report MAC CE includes information regarding beams corresponding to the number of beams, and the information regarding the beams may include a resource index related to a reference signal of a first beam that satisfied the conditions of the event during the time corresponding to the TTT, and a measured value of the first beam.

[0013] In addition, in a wireless communication system according to one example of the present disclosure, a terminal comprises: a transceiver; and a control unit that receives a radio resource control (RRC) message from a base station, the message including measurement resource setting information for an LTM (layer 1 / layer 2 triggered mobility) candidate cell and report setting information regarding an LTM measurement report, wherein the report setting information includes setting an event trigger-based measurement report, information regarding a time to trigger (TTT) related to the event, and information regarding the number of beams to be reported for measurement results, and measures a plurality of beams for the candidate cell based on the measurement resource setting information, and when a first beam satisfying the conditions of the event for a time corresponding to the TTT among the plurality of beams is identified, transmits an L1 measurement report MAC (medium access control) CE (control element) to the base station based on the report setting information, wherein the L1 measurement report MAC CE includes information regarding beams corresponding to the number of beams, and the information regarding the beams may include a resource index related to a reference signal of the first beam and a measurement value of the first beam.

[0014] In addition, in a wireless communication system according to one example of the present disclosure, a base station comprises: a transceiver; and a terminal, a radio resource control (RRC) message including measurement resource setting information for an LTM (layer 1 / layer 2 triggered mobility) candidate cell and reporting setting information regarding an LTM measurement report, wherein the reporting setting information includes setting an event trigger-based report, information regarding a time to trigger (TTT) related to the event, and information regarding the number of beams to be reported for measurement results, and a control unit that receives an L1 measurement report MAC (medium access control) CE (control element) from the terminal based on the reporting setting information, wherein the L1 measurement report MAC CE includes information regarding beams corresponding to the number of beams, and the information regarding the beams may include a resource index related to a reference signal of a first beam that satisfied the conditions of the event during the time corresponding to the TTT, and a measured value of the first beam.

[0015] According to one example of the present disclosure, the entire terminal operation for setting up event-based Layer 1 measurement reporting is specified, thereby enabling LTM event-based measurement reporting, and thereby has the effect of enabling LTM to be triggered more accurately.

[0016] FIG. 1 is a drawing illustrating the structure of a next-generation mobile communication system to which the present disclosure is applied.

[0017] FIG. 2 is a diagram showing the wireless protocol structure of a next-generation mobile communication system to which the present disclosure can be applied.

[0018] FIG. 3 is a drawing illustrating the structure of another next-generation mobile communication system to which the present disclosure may be applied.

[0019] FIG. 4 is a diagram illustrating a scenario for inter-cell beam management referenced in the present disclosure, in which a terminal transmits and receives data through the beam of a TRP (transmission / reception point) of a neighboring cell that supports beam changing based on L1 / L2 while maintaining a connection state with a serving cell.

[0020] FIG. 5a is a diagram illustrating a scenario in which a terminal according to an example of the present disclosure changes a serving cell and a beam to a TRP of a cell that supports L1 / L2-based beam changing to transmit and receive data.

[0021] FIG. 5b is a diagram illustrating a scenario in which a terminal according to an example of the present disclosure changes the serving cell and beam to the TRP of a cell that supports L1 / L2-based beam changing to transmit and receive data.

[0022] FIG. 6a is a diagram illustrating the overall operation for performing event-based Layer 1 measurement reporting in an LTM according to one example of the present disclosure.

[0023] FIG. 6b is a diagram illustrating the overall operation for performing event-based Layer 1 measurement reporting in an LTM according to one example of the present disclosure.

[0024] FIG. 6c is a diagram illustrating the overall operation for performing event-based Layer 1 measurement reporting in an LTM according to one example of the present disclosure.

[0025] FIG. 7 is a diagram illustrating the overall terminal operation that is applied to the examples of the present disclosure and performs an event-based L1 measurement report to perform an L1 / L2-based handover.

[0026] FIG. 8 is a drawing illustrating base station operation applied to embodiments of the present disclosure.

[0027] FIG. 9 is a block diagram illustrating the internal structure of a terminal to which the present disclosure is applied.

[0028] FIG. 10 is a block diagram showing the configuration of a base station according to one example of the present disclosure.

[0029] The operating principle of the present invention will be described in detail below with reference to the attached drawings. In describing the present invention below, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, such definitions should be based on the content throughout this specification. Terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc., are provided as examples for the convenience of explanation. Accordingly, the present invention is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0030] For convenience of explanation below, the present invention uses terms and names defined in the 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) standard. However, the present invention is not limited by the above terms and names and can be applied in the same way to systems conforming to other standards.

[0031] FIG. 1 is a drawing illustrating the structure of a next-generation mobile communication system to which the present disclosure is applied.

[0032] Referring to FIG. 1, as illustrated, the wireless access network of a next-generation mobile communication system consists of a next-generation base station (New Radio Node B, hereinafter NR NB, 1a-10) and an NR CN (New Radio Core Network, or NG CN: Next Generation Core Network, 1a-05). A user terminal (New Radio User Equipment, hereinafter NR UE or terminal, 1a-15) connects to an external network through the NR NB (1a-10) and the NR CN (1a-05).

[0033] In FIG. 1, the NR NB (1a-10) corresponds to the eNB (Evolved Node B) of the existing LTE (long term evolution) system. The NR NB (1a-10) is connected to the NR UE (1a-15) via a wireless channel and can provide superior service compared to the existing Node B. In the next-generation mobile 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 (1a-10). A single NR NB typically controls multiple cells. To achieve ultra-high-speed data transmission compared to existing LTE, the NR NB (1a-10) can have a bandwidth greater than the existing maximum bandwidth and can use Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as a wireless access technology, and additionally incorporate beamforming technology. In addition, the NR NB (1a-10) applies an Adaptive Modulation & Coding (hereinafter referred to as AMC) scheme that determines the modulation scheme and channel coding rate according to the channel conditions of the terminal.

[0034] The NR CN (1a-05) performs functions such as mobility support, bearer configuration, and QoS (quality of service) configuration. The NR CN (1a-05) is a device responsible for various control functions as well as mobility management functions for terminals, and is connected to multiple base stations. In addition, the next-generation mobile communication system can be interconnected with existing LTE systems, and the NR CN (1a-10) is connected to the MME (mobility management entity, 1a-25) via a network interface. The MME (1a-25) is connected to the existing base station eNB (1a-30).

[0035] FIG. 2 is a diagram showing the wireless protocol structure of a next-generation mobile communication system to which the present disclosure can be applied.

[0036] Referring to FIG. 2, the wireless protocol of the next-generation mobile communication system consists of NR SDAP (service data adaptation protocol, 1b-01, 1b-45), NR PDCP (packet data convergence protocol, 1b-05, 1b-40), NR RLC (radio link control, 1b-10, 1b-35), and NR MAC (medium access control, 1b-15, 1b-30) at the terminal and the NR base station, respectively.

[0037] The main functions of NR SDAP (1b-01, 1b-45) may include some of the following functions.

[0038] - User data transfer function (transfer of user plane data)

[0039] - Mapping function between a QoS flow and a DRB for both DL and UL for uplink and downlink

[0040] - Marking QoS flow ID for uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0041] - Function to map reflective QoS flow to data bearers for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0042] Regarding the 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, bearer, or 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 1-bit indicators for NAS (non-access stratum) QoS reflection (NAS reflective QoS) and AS (access stratum) QoS reflection (AS reflective QoS) of the SDAP header. The SDAP header may include QoS flow ID information indicating QoS. The QoS information may be used for data processing priority, scheduling information, etc., to support smooth service.

[0043] The main functions of NR PDCP (1b-05, 1b-40) may include some of the following functions.

[0044] ● Header compression and decompression features (ROHC only)

[0045] ● User data transfer function (Transfer of user data)

[0046] ● Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0047] ● Out-of-sequence delivery of upper layer PDUs

[0048] ● Reordering function (PDCP PDU reordering for reception)

[0049] ● Duplicate detection function (Duplicate detection of lower layer SDUs)

[0050] ● Retransmission of PDCP SDUs

[0051] ● Encryption and decryption functions (Ciphering and deciphering)

[0052] ● Timer-based SDU discard in uplink.

[0053] 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 a PDCP SN (sequence number), and may include a function of transmitting data to an upper layer in the reordered order, or a function of transmitting immediately without considering the order, may include a function of recording lost PDCP PDUs (protocol data units) by reordering, may include a function of reporting the status of lost PDCP PDUs to the transmitting side, and may include a function of requesting retransmission of lost PDCP PDUs.

[0054] The main functions of NR RLC(1b-10, 1b-35) may include some of the following functions.

[0055] ● Data transfer function (Transfer of upper layer PDUs)

[0056] ● Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0057] ● Out-of-sequence delivery of upper layer PDUs

[0058] ● ARQ Function (Error Correction through ARQ)

[0059] ● Concatenation, segmentation, and reassembly functions of RLC SDUs

[0060] ● Re-segmentation of RLC data PDUs

[0061] ● Reordering function (Reordering of RLC data PDUs)

[0062] ● Duplicate detection

[0063] ● Error detection function (Protocol error detection)

[0064] ● RLC SDU discard function

[0065] ● RLC re-establishment function

[0066] In the above, the in-sequence delivery function of the NR RLC device refers to the function of delivering RLC SDUs (service data units) received from a lower layer to an upper layer in sequence. It may include a function to reassemble and deliver them if a single RLC SDU is received divided into multiple RLC SDUs; a function to rearrange received RLC PDUs based on an RLC SN (sequence number) or PDCP SN (sequence number); a function to record lost RLC PDUs after rearranging the order; a function to report the status of lost RLC PDUs to the transmitting side; a function to request retransmission of lost RLC PDUs; a function to deliver only the RLC SDUs prior to the lost RLC SDU to the upper layer in sequence if there is a lost RLC SDU; or a function to deliver all RLC SDUs received before the timer started to the upper layer in sequence if a predetermined timer has expired, even if there is a lost RLC SDU. It may include a function to deliver all RLC SDUs received up to that point to the upper layer in order once a predetermined timer has expired, even if there are any lost RLC SDUs. Additionally, the RLC PDUs may be processed in the order they are received (regardless of the order of sequence numbers, but in the order of arrival) and delivered to the PDCP device out of order (out-of-sequence delivery). 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 then 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.

[0067] 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. It may include a function of reassembling and delivering them when a single RLC SDU is received divided into multiple RLC SDUs, and may include 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.

[0068] The NR MAC (1b-15, 1b-30) 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.

[0069] ● Mapping function (Mapping between logical channels and transport channels)

[0070] ● Multiplexing and demultiplexing of MAC SDUs

[0071] ● Scheduling information reporting function

[0072] ● HARQ function (Error correction through HARQ)

[0073] ● Priority handling between logical channels of one UE

[0074] ● Priority handling between UEs by means of dynamic scheduling

[0075] ● MBMS service identification

[0076] ● Transport format selection function

[0077] ● Padding

[0078] The NR PHY layer (1b-20, 1b-25) can perform the operation of channel coding and modulating upper layer data, creating OFDM symbols and transmitting them to the wireless channel, or demodulating OFDM symbols received through the wireless channel and channel decoding them to transmit them to the upper layer.

[0079] FIG. 3 is a drawing illustrating the structure of another next-generation mobile communication system to which the present disclosure may be applied.

[0080] Referring to FIG. 3, the cell serviced by the beam-based NR gNB (1c-05) can be composed of multiple TRPs (Transmission Reception Points, 1c-10, 1c-15, 1c-20, 1c-25, 1c-30, 1c-35, 1c-40). The TRPs (1c-10 to 1c-40) represent blocks from which some functions of transmitting and receiving physical signals from an existing NR base station (eNB) have been separated, and they are composed of multiple antennas. The NR gNB (1c-05) can be represented as a CU (Central Unit), and the TRPs (1c-10 to 1c-40) can also be represented as a DU (Distributed Unit). The functions of the NR gNB (1c-05) and the TRPs can be configured by separating each layer from the PDCP / RLC / MAC / PHY layer, such as 1c-45. That is, TRP (1c-15, 1c-25) can perform the functions of the corresponding layer using only the PHY layer, TRP (1c-10, 1c-35, 1c-40) can perform the functions of the corresponding layers using only the PHY layer and the MAC layer, and TRP (1c-20, 1c-30) can perform the functions of the corresponding layers using only the PHY layer, the MAC layer, and the RLC layer. In particular, TRP (1c-10~1c-40) can use beamforming technology to transmit and receive data by generating narrow beams in various directions using multiple transmitting and receiving antennas. The user terminal (1c-50) connects to the NR gNB (1c-05) and the external network through the TRP (1c-10~1c-40).

[0081] The above NR gNB (1c-05) collects status information such as the buffer status, available transmission power status, and channel status of terminals to provide services to users, and schedules them to support the connection between the terminals and the core network (CN), in particular the access and mobility management function (AMF) / session management function (SMF) (1c-50).

[0082] Hereinafter, the TRP in the present disclosure will be described by exemplifying a structure (1c-15, 1c-25) that has only a PHY layer and can perform the functions of that layer.

[0083] FIG. 4 is a diagram illustrating a scenario for inter-cell beam management referenced in the present disclosure, in which a terminal transmits and receives data through the beam of a TRP (transmission / reception point) of a neighboring cell that supports beam changing based on L1 / L2 while maintaining a connection state with a serving cell.

[0084] Although this drawing describes a case where multiple cells (TRP1-Cell1, TRP2-Cell2; 1d-10, 1d-15) exist within a single DU (Distributed unit, 1d-05), the general content of this disclosure is also applicable to inter-DU cases (each DU constitutes a single TRP-Cell). Furthermore, for convenience of explanation, in this disclosure, non-serving cells (TRP 2, Cell 2) that support L1 / L2-based mobility (beam change and serving cell change) are referred to interchangeably as neighbor cells, non-serving cells, and additional cells with a physical cell identity (PCI) different from the serving cell.

[0085] In the existing terminal beam change procedure (1d-45), the terminal (1d-20) transmits and receives data while connected to the serving cell 1 via the serving cell 1's TRP 1 (1d-10), and may be set to the optimal beam, the transmission configuration indicator (TCI) state 1 (1d-25, 1d-30). At this stage, the terminal (1d-20) may receive instructions for setting information for L3 channel measurement (RRM; radio resource management) for an additional cell (TRP 2-Cell 2, 1d-15) that has a different PCI from the serving cell through RRC setting information from the serving cell 1 (1d-10), and performs an L3 measurement operation (1d-46) for the corresponding frequency and cell based on this. Subsequently, serving cell 1 (TRP 1-Cell 1, 1d-10) may instruct the terminal (1d-20) to hand over to the corresponding cell (TRP 2-Cell 2, 1d-15) based on the measurement value reported from the terminal (1d-20) (1d-47), and after the handover is completed, additional RRC configuration information may be transmitted to the terminal (1d-20) through TRP 2-Cell 2 (1d-15) (1d-48). The RRC configuration information may include UL (uplink) / DL (downlink) configuration information in the corresponding cell, L1 measurement related settings (CSI (channel state information) - RS (reference signal) measurement and reporting), and in particular may include TCI state configuration information for PDCCH (physical downlink control channel) and PDSCH (physical downlink shared channel) channels. The terminal (1d-20) performs an L1 measurement according to the above settings (1d-49), and the base station updates the TCI state through L1 / L2 signaling according to the measurement report from the terminal (1d-20) (1d-50).Here, the optimal beam, TCI state 2 (1d-40), can be directed to the terminal (1d-20). At this stage, the serving cell of the terminal (1d-20) is Cell 1 (1d-10) until handover, and Cell 2 (1d-15) becomes the serving cell of the terminal (1d-20) after handover. That is, many procedures and time are required even after handover until the optimal beam is directed to the terminal (1d-20).

[0086] Unlike the existing terminal beam change procedure (1d-45) described above, the improved beam change technique (1d-55) considered in this disclosure is as follows. The RRC setting information (1d-56) transmitted from the serving cell (1d-10) to the terminal (1d-20) can be transmitted by referring to the beam setting associated with an additional cell (TRP 2-Cell 2, 1d-15) with a different PCI from the serving cell. Associating the beam setting, that is, the TCI state corresponding to TRP2, with the additional cell (TRP 2-Cell 2, 1d-15) with a different PCI from the serving cell is applied by a method of associating a new cell ID (Physical cell ID, PCI; additionalPCI-r17) with the corresponding TCI state as shown in [Table 1] below.

[0087]

[0088] In addition, for beam management between the cells, a unified TCI state framework as shown in [Table 2] below is applied. The unified TCI state framework applies a common TCI state framework to the uplink and downlink, and to the common channel and dedicated channel, and can be set to one of the Joint UL / DL mode as shown in [Table 3] below and the separate UL / DL mode as shown in [Table 4] below.

[0089]

[0090]

[0091]

[0092] After the terminal (1d-20) is provided with a setting for TRP 2-Cell 2 (1d-15) while connected to RRC in serving cell 1 (1d-10), it performs an L1 measurement for the corresponding TRP 2-Cell 2 (1d-15) according to the setting and reports the result to serving cell 1 (Cell 1, 1d-10) (1d-57). If serving cell 1 (1d-10) determines that a change to a specific beam (TCI state 2, 1d-35, 1d-40) of TRP 2 (Cell 2, 1d-15) is necessary from the serving cell beam (TCI state 1, 1d-25, 1d-30) based on the measurement result, it triggers a beam change and instructs the terminal (1d-20) to change the beam through L1 / L2 signaling (1d-58). The terminal (1d-20) changes the beam to a specific beam (TCI state 2, 1d-40) of TRP 2 (Cell 2, 1d-15) through the corresponding instruction, and performs physical channel setting and upper layer setting operations associated with the set beam. From this stage, the terminal (1d-20) remains connected to serving cell 1 (Cell 1, 1d-10), but performs data transmission and reception using the channel link of TRP 2 (Cell 2, 1d-15) (receiving PDCCH / PDSCH, transmitting PUCCH (physical uplink control channel) / PUSCH (physical uplink shared channel)). That is, transmission and reception for the common control channel are performed through serving cell 1 (Cell 1, 1d-10). Afterwards, the terminal (1d-20) performs an L3 measurement operation according to an independent measurement setting configured in the serving cell (1d-59), receives a handover command message from the serving base station (Cell 1) (1d-10), and can perform a serving cell change to Cell 2 (1d-15) (1d-60).Through this technique (1d-55), the terminal (1d-20) performs data transmission and reception with a specific TRP 2 (1d-15) of Cell 2 that supports L1 / L2-based mobility while connected to the serving cell, and can continue to use the beam even after handover.

[0093] For reference, the RRC settings for the settings and operations related to the L1 measurement and report in step 1d-57 above can be explained as follows with reference to [Table 5] and [Table 6] below. This content is basically applied to the embodiments below of the present disclosure, and enhancement techniques may be added in future embodiments.

[0094] 1. L1 measurement settings (configured within CSI-ResourceConfig and ServingCellConfig within IE)

[0095] - CSI-RS / SSB (synchronization signal block) resources and resource pools (nzp-CSI-RS, csi-IM, csi-SSB) requiring measurement

[0096] - Configuration of CSI-RS / SSB resources requiring measurement (aperiodic, semi-persistent) and triggering settings

[0097] - When a CSI-RS resource references an SSB resource, additional PCI information is provided to enable L1 measurement from neighboring cells (up to 7 neighboring cells (PCI) can be added from a single serving cell).

[0098]

[0099]

[0100] 2. L1 report settings (configured within the serving cell, ServingCellConfig, configured within IE)

[0101] - Report Type: Periodic Report, Semi-periodic Report with PUCCH, Semi-periodic Report with PUSCH, Aperiodic Report with PUSCH

[0102] - Report quantity

[0103] - Other settings required for reporting

[0104] FIGS. 5a and 5b are examples considered in the present disclosure, illustrating a scenario in which a terminal changes the serving cell and beam to the TRP of a cell that supports L1 / L2-based beam changing to transmit and receive data.

[0105] FIGS. 5a and 5b describe a case where multiple cells (TRP1-Cell1, TRP2-Cell2; 1e-10, 1e-15, 1e-40, 1e-45) exist within a single DU (Distributed unit, 1e-05, 1e-35), but the overall content of the present disclosure is also applicable to inter-DU within an intra-CU (each DU constitutes a single TRP-Cell).

[0106] Unlike the conventional terminal beam changing procedure (1d-45, 1d-55) described in detail in FIG. 4, the enhanced beam changing technique (1e-25, 1e-75) considered in the examples according to FIG. 5a and 5b is as follows.

[0107] 1. Example 1 (1e-25): After performing inter-cell beam management (change) operation, perform L1 / L2 handover

[0108] 2. Example 2 (1e-75): Perform L1 / L2 handover immediately

[0109] First, referring to FIG. 5a, the overall operation of Example 1 is described as follows: the terminal (1e-20) can receive common configuration and dedicated configuration information for an additional cell (TRP 2-Cell 2, 1e-15) that has a different PCI from the serving cell through RRC configuration information from serving cell 1 (1e-10) (1e-26). That is, configuration information corresponding to ServingCellID or candidateCellID (cell ID associated with PCI), ServingCellConfigCommon, and ServingCellConfig can be provided to the terminal (1e-20) in advance. The configuration information can be provided in the form of pre-configuration in the RRC configuration, and configuration information for multiple cells can be included in the RRC configuration. Furthermore, the configuration is characterized by including all configuration information (cell configuration, bearer configuration, security key configuration, etc.) that is applied when the terminal (1e-20) moves to the corresponding cell (handover). Furthermore, the said settings include enhanced settings by referring to the unified TCI state settings and L1 measurement and report settings described in step 1d-56 of FIG. 4. Specifically, enhanced unified TCI state settings and L1 measurement and report settings for continuous LTM are included in the RRC settings, which will be explained in detail below regarding the present invention.

[0110] As illustrated in FIG. 5a, after a setting for TRP 2-Cell 2 (1e-15) is provided while RRC is connected to serving cell 1 (1e-10), the terminal (1e-20) performs an L1 measurement for the corresponding TRP 2-Cell 2 (1e-15) according to the setting received in step 1e-27 and reports the result to the serving cell (Cell 1, 1e-10). If the serving cell determines that a change to a specific beam (TCI state 2, 1e-40) of TRP 2 (Cell 2, 1e-15) is necessary from the serving cell beam (TCI state 1, 1e-25) based on the measurement result, it triggers a beam change in step 1e-28 and instructs the terminal (1e-20) to change the beam through L1 / L2 signaling. The terminal (1e-20) performs a beam change to TRP 2 (Cell 2, 1e-15) through the corresponding instruction and performs data transmission and reception through the TRP 2 (Cell 2, 1e-15). At this time, no serving cell change occurs, and the terminal (1e-20) remains connected to the serving cell (Cell 1, 1e-10) via RRC. Subsequently, the terminal (1e-20) still performs an L1 measurement of TRP 2-Cell 2 (1e-15) and reports the result to the serving cell (Cell 1, 1e-10). The serving cell (Cell 1, 1e-10) instructs the terminal (1e-20) to perform a handover if the L1 measurement reported by the terminal (1e-20) satisfies the triggering condition for a handover to TRP 2-Cell 2 (1e-15) (detailed operation is described below). The instruction may be an L1 / L2 message. That is, the MAC CE (control element) may contain an indicator instructing the handover.

[0111] Referring to FIG. 5b, the overall operation of Embodiment 2 is described as follows: A terminal (1e-50) can receive common configuration and dedicated configuration information for an additional cell (TRP 2-Cell 2, 1e-45) with a different PCI from the serving cell (Cell 1, 1e-40) through RRC configuration information from the serving cell (Cell 1, 1e-40) (1e-76). That is, ServingCellID or candidateCellID (cell ID associated with PCI), and configuration information corresponding to the corresponding candidate LTM cell can be provided to the terminal (1e-50) in advance. The configuration information can be provided in the form of pre-configuration in the RRC configuration, and configuration information for multiple cells can be included in the RRC configuration. Furthermore, the configuration is characterized by including all configuration information (cell configuration, bearer configuration, channel measurement configuration, etc.) that is applied when the terminal (1e-50) moves to the corresponding cell (handover). In addition, to support continuous LTM, the settings related to the unified TCI state and L1 measurement and report described in steps 1d-56 of FIG. 4 are modified and included in the said settings. The L1 measurement and report and TCI state settings applicable to the present disclosure are described in detail below.

[0112] As illustrated in FIG. 5b, after a setting for TRP 2-Cell 2 (1e-45) is provided while RRC is connected to serving cell 1 (1e-40), the terminal (1e-50) performs an L1 measurement for the corresponding TRP 2-Cell 2 (1e-45) according to the setting received in step 1e-77 and reports the result to the serving cell (Cell 1, 1e-40). If the serving cell (1e-40) determines that a handover is required simultaneously with a beam change from the serving cell beam (TCI state 1, 1e-45) to a specific beam (TCI state 2, 1e-70) of TRP 2 (Cell 2, 1e-45) based on the measurement result, it triggers the beam change and handover in step 1e-78 and instructs the terminal (1e-50) to perform the beam change and handover through L1 / L2 signaling. The terminal (1e-50) performs a handover simultaneously with changing the beam to TRP 2 (Cell 2, 1e-15) via the corresponding instruction, and performs data transmission and reception through the TRP 2 (Cell 2, 1e-15). At this time, the terminal (1e-50) applies the configuration information for the target cell where the handover is performed, which was pre-configured in step 1e-76. Depending on whether uplink synchronization is required in this step, the terminal (1e-50) may perform random access, or random access to the target cell of the terminal (1e-50) may be omitted. Detailed operation is described below in the drawings.

[0113] In the following, in particular, as explained above, detailed methods for setting the unified TCI state and L1 measurement and report for candidate cells surrounding an LTM to support the continuous LTM proposed in this disclosure will be described. As illustrated in Figure 4, in the existing ICBM (inter-cell beam management), L1 measurement resource settings for cells requiring measurement are provided in the CSI-ResourceConfig within the ServingCellConfig IE included in the serving cell configuration. In particular, to indicate resources for surrounding cells, the PCI of the cell where the corresponding L1 measurement resource is set can be indicated in the servingAdditionalPCIList.

[0114] Detailed settings for L1 measurement and reporting settings for LTM are provided as L1 measurement resource settings applied to LTM candidate cells, as shown in [Table 7] through [Table 10] below. To this end, it is necessary to share and determine the L1 measurement resources and reporting settings for LTM among LTM candidate cells during the preprocessing stage. The entire procedure related to this is explained together in the following examples. The following examples are explained with reference to the settings below.

[0115] 1. L1 measurement resource configuration (configured within LTM-CSI-ResourceConfig and LTM-Config)

[0116] - CSI Resource configuration index exists to specify CSI resource settings (LTM-CSI-ResourceConfigId-r18)

[0117] - CSI resource set containing CSI-RS or SSB resources requiring measurement

[0118] - A single CSI resource set can be multiple SSB resources or CSI-RS resources existing within an LTM candidate cell.

[0119] 2. L1 report settings (configured within LTM-Config)

[0120] - CSI Report configuration index exists to specify CSI reporting settings (LTM-CSI-ReportConfig-r18)

[0121] - Report Type: Periodic Report, Semi-periodic Report with PUCCH, Semi-periodic Report with PUSCH, Aperiodic Report with PUSCH

[0122] - Report Content (Number of reporting cells, number of reporting resources, etc.)

[0123]

[0124]

[0125]

[0126]

[0127] 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. Furthermore, the method for setting and reporting event-based L1 measurement information is described in detail, and in particular, details regarding which beam is the measurement target and which is used as a comparison target for event L1 measurement are explained.

[0128] FIGS. 6a, 6b, and 6c illustrate the overall operation for performing event-based Layer 1 measurement reporting in LTM as an example of the present disclosure. Based on these figures, the overall operation applying L1 measurement resources and reporting settings to support continuous L1 / L2-based handover (LTM) operations in cells within different CUs will be described.

[0129] Referring to FIG. 6a, the terminal (1f-01) in the RRC connection state performs data transmission and reception with source cell 1 (1f-02), and then transmits Layer 3 measurement values ​​for the serving cell and surrounding cells to the source base station (1f-03) according to the Layer 3 measurement and reporting set in step 1f-10. At this time, the actual measurement values ​​are transmitted to the base station CU (1f-03). This is because the base station CU (1f-03) is responsible for processing RRC messages and determining mobility.

[0130] Based on the measurement report received from the terminal (1f-01), the base station CU (1f-03) generates a message (UE Context Setup Request or UE Context Modification Request) requesting configuration information for L1 / L2-based handover from the intra-CU's LTM candidate surrounding cells (1f-04, 1f-05) and transmits it to the F1 interface (1f-15). In FIG. 6a, the candidate cells are shown in association with the DU, but in reality, the candidate cells and the DU may be mapped 1:1, or multiple candidate cells may be included in a single DU. Additionally, the message requesting configuration information for L1 / L2-based handover may be a UE context request message, a UE context modification request message, etc., or a new F1 message. The message requesting configuration information for the L1 / L2-based handover described above may include a procedure for requesting neighboring cells to be determined as L1 / L2-based handover candidate cells, and simultaneously requesting RRC configuration information applicable when an L1 / L2-based handover is performed to said cell. That is, information requesting L1 measurement resources and reporting settings for the LTM candidate cells proposed in this disclosure may be included in the message requesting configuration information for the L1 / L2-based handover. More specifically, the information that may be included in said message is summarized as follows.

[0131] 1. Configuration information applicable to LTM and conditional LTM (Information to be displayed when issuing the cell switch command MAC CE instruction to the candidate cell that made the LTM decision.)

[0132] - LTM candidate ID

[0133] - Mapping information between LTM candidate ID and corresponding cell ID

[0134] - Beam information (TCI state) to be used by each candidate

[0135] ■ In this case, the meaning of the beam to be used may include a beam linked to the RACH occasion when performing DL and / or UL synchronization and / or RACH (random access channel) procedures, and / or a beam to be used for the first UL data transmission. If necessary, an indicator corresponding to each case may be provided to perform a cell switch.

[0136] - RACH preamble index

[0137] - SSB index: An index of the SSB used to determine the RACH occasion in each candidate cell, where the RACH occasion may refer to the occasion for transmitting the RACH preamble of CFRA (contention-free random access).

[0138] 2. Pre-configuration procedures for LTM and conditional LTM

[0139] - CSI resource request information for each candidate cell (requests for CSI-RS resources or SSB resources)

[0140] ■ It may be requested during the pre-configuration preprocessing section for LTM candidate cells.

[0141] ◆ Indicator for whether the request is for initial preparation, e.g., initiation, or for a modification request after the initial one

[0142] ■ In particular, when the relevant request information is included, lower layer configuration information and CSI report configuration information in this message may not be transmitted.

[0143] ■ If CSI resource information is received from candidate cells as the relevant request information, the CSI resource settings of each of the following candidate cells may be transmitted instead of the request. In other words, a CSI resource setting preprocessing procedure is required in at least two steps.

[0144] In addition, it is possible to decide whether to request CSI-RS resources or SSB resources for each target candidate cell.

[0145] - CSI resource settings for each candidate cell (necessary when transmitting L1 measurement settings as source DU to the terminal), individual resource settings per cell and setting IDs, CSI resource settings for LTM, and may use the same CSI resources as conditional LTM, but may also be transmitted with explicit distinction for conditional LTM.

[0146] ■ Based on the above CSI resource request information, provide L1 measurement settings for LTM transmitted from the corresponding candidate cell.

[0147] ■ Depending on the request for CSI-RS or SSB resources from each target cell, one of the two resource configurations or both resource configurations can be delivered.

[0148] - CSI report configuration considering the CSI resources of each of the above candidate cells

[0149] The purpose of this is that when a candidate DU creates the above information and transmits it to a CU, this information can be used as the CSI report configuration within the target cell configuration (RRCReconfiguration) of the relevant concerned cell (i.e., 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).

[0150] ■ In other words, if the terminal moves from another cell to this cell (concerned cell), it can be used as a CSI report configuration with that cell as the serving cell. It is intended to be included in the target cell configuration for subsequent LTM without providing separate L1 settings.

[0151] ■ Event-based L1 measurement reporting

[0152] You can define and use Best beam's L1-RSRP-based events.

[0153] ◆ For example, events such as those shown in [Table 11] below can be introduced. That is, events are 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.

[0154]

[0155] The above event may also be used in 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.

[0156] The above conditions are determined by coordination between the serving CU and the LTM candidate DU in step 1f-15, and the serving CU can determine the event conditions and L1 filtering values ​​that trigger the LTM provided by the LTM candidate cell and transmit them to the terminal.

[0157] - RACH configuration and lower layer setting information to be used in the concerned cell

[0158] ■ These information can be transmitted from the above candidate DU to the CU, written as settings required for RACH execution within the target cell configuration of the concerned cell, lower layer settings to be applied when moving to the cell, and / or reference settings including them, and later transmitted to the terminal.

[0159] ■ 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.

[0160] ■ 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.

[0161] Although Figure 6a illustrates a single procedure of steps 1f-15, the steps may be applied over multiple procedures. For example, the base station CU (1f-03) may request LTM-related settings for each LTM candidate cell, transmit the settings organized by the source cell once again, and then determine the necessary LTM settings and transmit them to the source cell. Refer to the following procedure for this.

[0162] 1. Step 1 (1f-15): Request L1 measurement resource configuration from LTM candidate cells (request SSB or CSI-RS resources)

[0163] 2. Step 2 (1f-25): LTM candidate cells respond by transmitting L1 measurement resource settings to the source base station CU (1f-03) (SSB or CSI-RS resource request). This procedure can be transmitted to the source base station via the F1 interface as a UE Context Setup Response message.

[0164] 3. Step 3 (1f-30): The source base station CU (1f-03) transmits L1 measurement resource settings for continuous LTM support to each candidate cell through the L1 measurement resource settings for each collected candidate cell. This procedure can be transmitted to the source base station via the F1 interface as a UE Context Modification Request message.

[0165] 4. Step 4 (1f-35): The source base station CU (1f-03) requests and receives L1 measurement report setup from LTM candidate cells. This procedure can be transmitted to the source base station via the F1 interface as a UE Context Modification Response message.

[0166] For reference, the above UE Context Setup / Modification related messages may be used exclusively for CSI-RS requests and responses by introducing other messages.

[0167] 5. Step 5 (1f-40): Deliver LTM-related settings to the terminal. The source base station collects all LTM-related settings received from LTM candidate cells, stores them in an RRCReconfiguration message delivered to the terminal, and delivers the corresponding RRC setting information to the terminal. That is, pre-configuration information for LTM candidate cells is delivered to the terminal.

[0168] In particular, the examples of the present disclosure intend to explain in detail how, when a beam of a source cell is determined in relation to an event-based L1 measurement report, specific beams of an LTM candidate cell are measured, how beams satisfying the conditions are ultimately reported in an event-based L1 measurement report, and what information is included in the MAC CE used for the report. More detailed information regarding this will be described later with reference to FIG. 7.

[0169] Referring again to FIG. 6a, the base station CU (1f-03) generates a message (Handover Request or new message) requesting configuration information for LTM from the target base station (CU2; 1f-06) in step 1f-20 for an LTM candidate cell configuration request for an LTM surrounding cell (1f-07) of the inter-CU based on a measurement report received from the terminal (1f-01), and transmits it to the X2 interface. Subsequently, in step 1f-25, the target base station (CU2; 1f-06) generates a message (UE Context Setup Request or UE Context Modification Request) requesting configuration information for LTM cell modification for an LTM candidate cell (1f-07) belonging to the CU, and transmits it to the F1 interface, and receives a message (UE Context Setup Response or UE Context Modification Response) responding with configuration information for LTM in response to the request. The procedure is similar to the LTM setting preprocessing procedure in Fig. 1f-15.

[0170] Subsequently, in step 1f-30, the target base station (CU2; 1f-06) generates a message (Handover Response or a new response message) to the source base station (CU; 1f-03) via the X2 interface, including the LTM candidate configuration information transmitted by the LTM candidate cell (1f-07) belonging to the CU. The content that can be newly added to the LTM configuration request message via the X2 interface in step 1f-30 is summarized as follows.

[0171] - Indicator for LTM execution

[0172] Additionally, an indicator indicating whether the request is for initial preparation, e.g., initiation, or for modification after the initial request.

[0173] - Device ID

[0174] - Source CU and / or Source DU ID, and / or the Source DU's TNL (Transport Network Layer) address (e.g., IP (Internet Protocol) address)

[0175] - ID of the requested candidate cell (PCI or NR CGI (cell global identity) with NR ARFCN (absolute radio frequency channel number))

[0176] - LTM configuration ID of this candidate cell (If accepted, the source DU can use the LTM config ID when cell switching to the target cell.)

[0177] - 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.

[0178] ■ Opt 1. The above candidate cell list may be a list of candidate cells operated by all candidate CUs for the terminal in question, and

[0179] ■ Opt 2. It may be a list containing only candidate cells operated by the source CU that transmits the HO request message.

[0180] - Request information for CSI resource configuration for LTM L1 measurement

[0181] ■ CSI resource requests are omitted, and configuration information for CSI resources being transmitted by all currently configured candidate cells may be transmitted.

[0182] ■ Request for SSB or CSI-RS resources

[0183] You can request only one of the two resources, or you can request both resources.

[0184] - An indicator requesting PRACH (physical random access channel) resource information for target candidate cells

[0185] - An indicator requesting a lower layer setting for target candidate cells

[0186] In addition to the information above, it is obvious that information previously used in HO request messages can also be included in the LTM configuration request message. In this regard, [Table 12] below may be referenced.

[0187] Source NG-RAN node UE XnAP ID referenceNG-RAN node UE XnAP ID9.2.3.16Allocated at the source NG-RAN nodeCause9.2.3.2Target Cell Global ID9.2.3.25Includes either an E-UTRA CGI or an NR CGIGUAMI9.2.3.24UE Context Information>NG-C UE associated Signalling referenceAMF UE NGAP ID9.2.3.26Allocated at the AMF on the source NG-C connection.>Signalling TNL association address at source NG-C sideCP Transport Layer Information9.2.3.31This IE indicates the AMF's IP address of the SCTP association used at the source NG-C interface instance.NOTE: If no UE TNLA binding exists at the source NG-RAN node, the source NG-RAN node indicates the TNL association address it would have selected if it would have had to create a UE TNLA binding.>UE Security Capabilities9.2.3.49>AS Security Information9.2.3.50>Index to RAT / Frequency Selection Priority9.2.3.23>UE Aggregate Maximum Bit Rate9.2.3.17>PDU Session Resources To Be Setup List9.2.1.1Similar to NG-C signalling, containing UL tunnel information per PDU Session Resource;and in addition, the source side QoS flow ⇔ DRB mapping>RRC ContextOCTET STRINGEither includes theHandoverPreparationInformationmessage as defined in subclause 10.2.2. of TS 36.331

[0014] , or theHandoverPreparationInformation-NBmessage as defined in subclause 10.6.2 of TS 36.331

[0014] , if the target NG-RAN node is an ng-eNB,or theHandoverPreparationInformationmessage as defined in subclause 11.2.2 of TS 38.331

[0010] , if the target NG-RAN node is a gNB.>Location Reporting Information9.2.3.47Includes the necessary parameters for location reporting.>Mobility Restriction List9.2.3.53>5GC Mobility Restriction List Container9.2.3.100>NR UE Sidelink Aggregate Maximum Bit Rate9.2.3.107This IE applies only if the UE is authorized for NR V2X services.>LTE UE Sidelink Aggregate Maximum Bit Rate9.2.3.108This IE applies only if the UE is authorized for LTE V2X services.>ManagementBasedMDT PLMN ListMDT PLMN List9.2.3.133>UE Radio Capability ID9.2.3.138>MBS Session Information List9.2.1.36>5G ProSe UE PC5 Aggregate Maximum Bit RateNR UE Sidelink Aggregate Maximum Bit Rate9.2.3.107This IE applies only if the UE is authorized for 5G ProSe services.>UE Slice Maximum Bit Rate List9.2.3.167>NR A2X UE PC5 Aggregate Maximum Bit RateNR UE Sidelink Aggregate Maximum Bit Rate9.2.3.107This IE applies only if the UE is authorized for NR A2X services.>LTE A2X UE PC5 Aggregate Maximum Bit RateLTE UE Sidelink Aggregate Maximum Bit Rate9.2.3.108This IE applies only if the UE is authorized for LTE A2X services.Trace Activation9.2.3.55Masked IMEISV9.2.3.32UE History Information9.2.3.64UE Context Reference at the S-NG-RAN node>Global NG-RAN Node ID9.2.2.3>S-NG-RAN node UE XnAP IDNG-RAN node UE XnAP ID9.2.3.16.

[0188] Subsequently, in step 1f-35, the source base station (1f-02) can trigger the procedures 1f-15 (transmitting the finally determined CSI resource settings to LTM candidate cells within the CU, requesting LTM-related settings, and receiving a response thereto) and 1f-20 (transmitting the finally determined CSI resource settings to LTM candidate cells within another CU and requesting LTM-related settings) again based on the information of LTM-related candidate cells received from the target base station (1f-06). In addition, in response to this, the procedure 1f-30 (receiving LTM-related settings based on the finally transmitted CSI resource settings from LTM candidate cells within another CU) can be performed.

[0189] Referring to FIG. 6b, in step 1f-40, the source base station (1f-02) collects all LTM-related settings received from LTM candidate cells and includes them in an RRCReconfiguration message transmitted to the terminal (1f-01), and transmits the corresponding RRC configuration information generated accordingly to the terminal (1f-01). That is, pre-configuration information for LTM candidate cells is transmitted to the terminal (1f-02). At this time, the source base station CU (1f-03) may include the source cell configuration information and separate reference cell configuration information in the RRC configuration information and transmit them. In the present disclosure, the reference cell configuration information may include L1 measurement resource settings for continuous LTM.

[0190] The reference cell configuration information transmitted by the source base station CU (1f-03) to each candidate cell (1f-04, 1f-05) above can be provided as common configuration information applicable to multiple target candidate cells so as to reduce signaling overhead when target candidate cells provide configuration information for LTM. This may include measurement configuration, bearer configuration, or, if the cells belong to the same CellGroup, configurations set at the CellGroup level (e.g., MAC-CellGroupConfig, RLC bearer configuration, SCell configuration, etc.). Alternatively, if the source base station CU (1f-03) has a procedure to roughly know or know the configuration information for each candidate cell (1f-04, 1f-05, 1f-07), 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 (1f-03) transmitting reference cell settings to each candidate cell (1f-04, 1f-05, 1f-07) is to allow the delta configuration method (a method of configuring a complete setting by applying settings added on top of the reference cell settings, or a method of configuring a complete setting by applying settings overridden in the target cell based on the reference cell settings) to the source base station CU (1f-03). Since this is transmitted to the terminal as is, it has the effect of reducing the signaling overhead of the RRC message transmitted to the terminal. In addition, when the source base station CU (1f-03) transmits reference cell settings to each candidate cell (1f-04, 1f-05, 1f-07), it may be omitted, in which case the candidate cell settings are provided as complete RRC settings. That is, it can be provided in the form of "RRC settings of all candidate cells = reference cell settings + candidate cell settings".

[0191] In step 1f-40, the source cell (1f-02) receives an RRC message from the base station CU (1f-03) that is generated based on configuration information received from each candidate cell by the base station CU (1f-03), and transmits it to the terminal (1f-01). The RRC message contains configuration information for surrounding candidate cells to which L1 / L2-based handover (LTM) is applied. The RRC message specifically includes a configuration indicating which TCI state will become the reference beam of the source cell for the LTM event-based L1 measurement report proposed in this disclosure, and L1 resources of the target cell to be measured.

[0192] In step 1f-45, the terminal (1f-01) that receives the corresponding RRC message performs a procedure to decode and process the RRC message. The processing includes ASN.1 decoding of the received message, validation, and methods for storing and managing configuration details. Additionally, the terminal (1f-01) stores the LTM configuration information for each candidate cell decoded in this step as complete configuration information in the terminal's buffer (memory), and simultaneously stores the received reference cell configuration information in the terminal's buffer (memory) as well, and manages it for subsequent operations. In the RRC message (or configuration information for each LTM candidate cell) in step 1f-40, the reference cell configuration information may be omitted. In this case, the terminal (1f-01) realizes that the reference cell configuration information is not included in the RRC message, determines the configuration information for the received LTM target candidate cells as complete configuration information, and stores it. At this time, the reference cell configuration information is not stored separately (operates as empty). That is, delta configuration is not applied. In addition, the above message conveys L1 measurement resources and reporting setting information for continuous LTM. For detailed settings, refer to the descriptions set forth in the present disclosure.

[0193] Although the present disclosure primarily deals with event-based L1 channel measurement and reporting, other forms of L1 channel measurement and reporting may be established separately, and a terminal according to one example of the present disclosure may perform L1 channel measurement and reporting based thereon. Although omitted in the drawings, existing L1 measurement and reporting procedures may be additionally applied.

[0194] Based on this, in step 1f-50, the base station (1f-02) instructs the terminal (1f-01) to use a TCI state to indicate the optimal beam used in the corresponding serving cell as a unified TCI state activation MAC CE. Upon receiving this, the terminal (1f-01) performs the event-based L1 resource measurement and evaluation steps considered in the present disclosure in step 1f-55, and when the execution conditions for a specific event are satisfied, transmits an L1 measurement report through an event-based L1 measurement MAC CE in step 1f-60.

[0195] Upon receiving this, the source base station (1f-02) refers to the corresponding L1 measurement value and transmits a command to the terminal (1f-01) in step 1f-65 to instruct it to change the LTM cell. In the above step, a MAC CE including a handover indicator may be used as the L1 / L2 signaling. If there is a need for a RACH-less LTM prior to this step, a procedure for obtaining a TA for the corresponding target cell may be added. The LTM is finally determined by the source cell, and the source cell does not transmit the L1 measurement value to the base station, but instead determines the handover itself based on the measurement criteria (threshold and measurement range) for making a handover decision for each candidate surrounding cell received from the previous base station, and then transmits the L1 / L2 signaling to the terminal to instruct it. Afterward, the source cell transmits the LTM determination information to the CU.

[0196] Referring to FIG. 6c, when an L1 / L2 handover instruction is transmitted to the terminal (1f-01), the terminal (1f-02) starts the handover procedure in step 1f-70 and starts 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.

[0197] In step 1f-75, the terminal (1f-01) applies a setting for the target cell to which L1 / L2 handover is applied. That is, the terminal (1f-01) replaces the current setting with the complete setting information of the LTM target cell instructed by the base station, which was previously stored in the terminal. This is one of the LTM candidate surrounding cell settings received in advance in step 1f-40 and is a setting stored in the terminal (1f-01).

[0198] According to the settings applied in step 1f-80, the terminal (1f-01) performs random access if random access is required for the corresponding target cell, and if random access is not instructed or is not required (if uplink synchronization has already been performed or matched), the random access procedure is omitted.

[0199] In step 1f-85, the terminal (1f-01) performs a handover completion procedure with the target cell. The completion procedure may be a handover completion procedure for the LTM. Additionally, this procedure is a process of delivering an RRCReconfiugrationComplete message to the RRC message configured by the target cell, and the actual handover completion is determined by the end of the random access process.

[0200] In step 1f-90, the target cell (DU, 1f-04) that receives the handover completion message can transmit the received message to the base station CU (1f-03). At this time, the handover completion message received through the F1 interface can be transmitted to the base station CU (1f-03) as is, or the message can be newly processed based on the received information and transmitted to the base station CU (1f-03). Subsequently, in step 1f-95, the base station CU (1f-03) can transmit information about the handover completion to the source cell (1f-02) and instruct it to release the terminal context.

[0201] In addition, as in step 1f-100, the embodiment of the present disclosure supports a subsequent LTM operation. A subsequent LTM operation is a process in which the LTM configuration information (such as configurations for target candidate cells and reference cell configuration information) received by the terminal in step 1f-40 is stored in the terminal as is, and the terminal continues to perform the LTM procedure based on the stored configuration unless the LTM configuration information is changed, disabled, or added through a separate RRC configuration. If it is necessary to update the reference cell configuration information, new RRC configuration information is transmitted to the terminal to perform the update operation. That is, the update operation of the reference cell configuration information for the terminal can be performed by re-triggering the procedure described in the drawings.

[0202] In summary, if the terminal receives reference cell configuration information in step 1f-40, it stores it in the terminal buffer, and if there is no update to a separate configuration, it continues to use that configuration as reference cell configuration information even after LTM execution (step 1f-70) (i.e., applies the reference cell configuration and LTM candidate configuration values ​​stored in successive LTMs). Additionally, if the terminal does not receive reference cell configuration information in the RRC connection state in step 1f-40, it may store the reference cell configuration as empty according to the terminal operation option described above, or store the configuration information for the source cell (primary cell, PCell) that received the LTM configuration information as reference cell configuration information.

[0203] FIG. 7 is a diagram illustrating the overall terminal operation that is applied to the examples of the present disclosure and performs an event-based L1 measurement report to perform an L1 / L2-based handover.

[0204] In particular, the present disclosure proposes an internal operation (a beam-based TimeToTrigger method) for triggering an event for an event-based L1 measurement report in the terminal operation of the present disclosure, and information included in the actual event-based L1 measurement report.

[0205] In step 1g-05, the connected terminal can receive configuration information from surrounding cells and LTM-related settings from the serving cell, which are applied after L1 / L2-based movement is instructed via an RRC reset message. For detailed configuration methods and content, refer to the contents of FIGS. 6a, 6b, and 6c. In particular, the present disclosure is characterized by receiving L1 event-based measurement reporting settings for LTM operation, and below, it will be explained that TimeToTrigger (TTT) related settings, which are primarily proposed in the present disclosure, are included in the L1 event-based measurement reporting settings. This relates to the fact that if a specific beam within an LTM candidate cell that satisfies an LTM event for an L1 measurement value satisfies a threshold condition, and the beam continues to satisfy the condition for a specific time, the event is finally triggered so that the terminal performs an event measurement report. For reference, the TTT function can be configured per L1 event and is set to a specific time value. In addition, although the explanation has been omitted, prior to the 1g-05 stage of receiving the above RRC configuration information, the terminal has received basic RRC configuration from the base station and performs the operation of reporting layer 3 measurements for surrounding cells to the base station. In particular, the configuration information in the LTM candidate cell applied after the L1 / L2-based movement received in the 1g-05 stage is transmitted with a delta configuration applied based on the configuration of a single reference cell.

[0206] In the 1g-10 stage, 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 (i.e., the operation of storing 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 instead store and manage the received RRC settings as they are in the buffer. As described in FIGS. 6a, 6b, and 6c, if the reference cell settings are omitted from the RRC settings when received, the terminal recognizes that there is no reference cell setting information and determines the setting information for the received LTM target candidate cells as complete setting information and stores it. In particular, in the present disclosure, LTM-related settings are provided in that stage, and specifically, the settings for candidate cells for LTM and L1 resources requiring measurement are included in the LTM-related settings. The terminal can decode the settings, store them in the terminal buffer, and then manage them.

[0207] In the 1g-15 stage, the terminal receives instructions from the base station via MAC CE regarding the TCI state applied to the source cell. Among the beams indicated by the MAC CE, the source cell beam used for actual event-based L1 measurement evaluation may be an activation beam indicated by the MAC CE or DCI (downlink control information), and, for example, may be a beam for receiving PDCCH or a beam for receiving PDSCH indicated by the scheduling DCI. The terminal determines the source cell beam according to the instructions from the base station and subsequently uses the determined beam as the reference source cell beam for evaluating each event for L1 event-based measurement reporting.

[0208] Subsequently, in step 1f-20, the terminal performs an L1 measurement configured with an SSB or CSI-RS resource associated with a nearby LTM candidate cell while maintaining a connection with the cell. That is, it measures the L1 measurement resources for the LTM candidate cells configured to be measured (more precisely, multiple CSI measurement resources configured within a set of CSI resources for the candidate cells) and compares this with the current beam of the serving cell to determine whether the conditions of the configured LTM event are satisfied. The LTM event here may be one of Event LTM2, Event LTM3, Event LTM4, and Event LTM5 described in FIGS. 6a to 6c. For example, if Event LTM3 (Beam of candidate cell becomes amount of offset better than beam of serving cell) is set, if any beam within the set CSI resource set measures a value that is better by a preset offset compared to the designated beam of the current source cell (reference beam for LTM event-based measurement), the terminal in step 1g-25 starts TTT and checks the condition of whether it maintains the operation until the TTT expires, that is, whether the state of measuring a value better by the said offset is maintained. Here, the following method is proposed as a method to reset the TTT value based on the beam-based measurement value.

[0209] - 1st beam-based TTT operation method

[0210] ■ The terminal performs beam-based L1 measurements and determines TTT operations based only on a specific beam (the beam that satisfied the first LTM event).

[0211] ■ Start the TTT from the beam that first satisfies a specific LTM event within the CSI resource set, and reset the TTT if that beam does not satisfy the LTM event condition.

[0212] ■ In this case, the TTT is reset even if the beam of the current source cell changes.

[0213] - 2nd Beam-Based TTT Operation Method

[0214] ■ The terminal performs beam-based L1 measurements, and after a specific beam first satisfies an LTM event, it maintains the TTT operation if any beam within the CSI resource set satisfies the LTM event (the TTT is not reset; that is, even if a single beam initially satisfies the LTM event condition, measurement and evaluation continue for beams within the same CSI resource set).

[0215] ■ Even in this case, the TTT can be reset if the current source cell's beam changes. Alternatively, in this case, the TTT operation can continue to be applied based on the previous source cell's beam even if the source cell's beam changes. That is, the source cell's beam continues to be used even if the current source cell's beam changes, until reporting for a single initiated LTM event is complete.

[0216] In the above 1g-25 step, detailed operations for the LTM event, namely L1 resource measurement and evaluation and detailed TTT operations, are applied, and when the TTT initiated for a specific LTM event expires, the terminal generates an LTM event-based measurement report MAC CE in the 1g-30 step. The MAC CE may include information related to the measurement values ​​as follows.

[0217] - Event-satisfying beam information: Information (index) about the SSB or CSI-RS resource to be reported

[0218] - Measured beam value: L1-RSRP or SINR (up to RAN1) value

[0219] - Triggered LTM measurement event information: For example, ReportConfigID

[0220] - Source cell beam information (sPCell beam information: may include the beam used for LTM events or the best beam)

[0221] In addition, regarding the above measurement information, depending on whether one beam or multiple beams are included, the following method is proposed.

[0222] - Option 1: The terminal reports only one beam that triggered the LTM event

[0223] ■ Here, one beam may be the beam used for LTM event evaluation at TTT expiration.

[0224] Or it could be the beam that triggered the first LTM event and started TTT.

[0225] - Option 2: The terminal triggers an LTM event and reports measurements for all beams in the CSI resource set that include the beam that initiated the TTT.

[0226] ■ In this case, a method is needed to determine which beam is actually the best among multiple beams.

[0227] ■ Method for sequentially including measurement beam results in MAC CE

[0228] ■ How to add an index to indicate the beam intensity order next to the measurement beam results

[0229] - Option 3: A method in which the base station sets the number of beams that it actually needs to report to the terminal, and the terminal reports accordingly.

[0230] ■ For example, if there are 3 beams configured within the CSI resource set to which the beam that triggered the LTM event and started the TTT belongs, and the report setting is configured to report only 2 beams, the terminal reports only the 2 beams with the strongest beam strength among the measurements within the CSI resource set.

[0231] ■ In this case, a method is needed to determine which beam is actually the best among multiple beams.

[0232] ■ Method for sequentially including measurement beam results in MAC CE

[0233] ■ How to add an index to indicate the beam intensity order next to the measurement beam results

[0234] In step 1g-35, the terminal transmits the event-based measurement report MAC CE generated in the above step to the base station. The MAC CE may include the information described in 1g-25. The serving cell may 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 instructs the terminal to hand over and change the beam through L1 / L2 signaling.

[0235] In the 1g-40 stage, the terminal can continue to perform the corresponding L1 measurement and evaluation when a TTT reset occurs for a specific triggered LTM event or when the event-based LTM measurement report event is no longer satisfied.

[0236] FIG. 8 is a drawing illustrating base station operation applicable to examples of the present disclosure.

[0237] In step 1h-05, the base station receives L3 measurement reports from the terminal and, based on the terminal's measurements regarding surrounding frequencies and cells, determines whether the terminal requires a handover and which cells are handover candidate cells.

[0238] In step 1h-10, the base station requests configuration information for L1 / L2-based handover from surrounding cells and receives responses from those cells. In this step, the base station transmits configuration information for the current source cell and reference cell configuration information together to the surrounding cells, and receives RRC configuration information from the surrounding cells and LTM candidate cells, to which delta configuration is applied based on the reference cell configuration information. Additionally, in this step, inter-node coordination for L1 measurement resources and reporting settings proposed in this disclosure is performed. The procedure described in detail in FIGS. 6a through 6c is included in this step, and in particular, the operation of determining L1 measurement resources and reporting settings within intra-CU and inter-CU is included in this step. Although omitted in this figure, prior to step 1h-10, settings related to L3 measurement settings and basic RRC settings are already provided to the terminal.

[0239] In step 1h-15, the base station transmits an RRC configuration message to a connected terminal, which includes the surrounding cell configuration information and L1 measurement resource / reporting settings received in step 1h-10. That is, the configuration information from the surrounding cell, which is applied after L1 / L2-based movement is instructed via an RRC reset message from the serving cell, is transmitted to the terminal. Detailed configuration methods and contents are described in detail in FIGS. 6a to 6c.

[0240] Subsequently, in step 1h-20, 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 that the base station wishes to configure and trigger. For details on the method, refer to the description above. Reports regarding L1 and L3 measurements are received from the terminal, and the present disclosure considers the case where an event-based L1 measurement report MAC CE is received from the terminal in that step. In this case, the L1 measurement may be a measurement for a non-serving cell that supports L1 / L2-based mobility.

[0241] The serving cell can determine whether to change the terminal's beam and perform a handover based on the received measurement results. If it is determined that a change to a specific beam of a neighboring cell is necessary rather than the serving cell's specific beam, the serving cell instructs the terminal to perform an LTM handover via L1 / L2 signaling in step 1h-25. The above L1 / L2 signaling may be a MAC CE, and the MAC CE includes information instructing a change to a specific beam of a neighboring cell. Additionally, in that step, the serving cell may also be instructed to perform an existing handover via an RRC message independently of the MAC CE. This may occur because the base station and the serving cell independently determine the LTM and Layer 3 handover.

[0242] Subsequently, in step 1h-35, when the base station receives a handover completion message from the terminal, it confirms that the corresponding LTM operation has been successfully completed, and accordingly notifies the previous source cell of the handover completion and requests the release of the terminal context. Additionally, if it receives a handover failure report message containing information that the handover failed from the terminal, it receives a message indicating that the terminal attempted to reconnect to that cell after the handover failure. The handover failure report message may be a UEInformationResponse or another uplink RRC message. Furthermore, information regarding the handover failure report may be transmitted via a new MAC CE or uplink control signal (UCI; uplink control information). The information included in the handover failure report message may include the following information.

[0243] - An indicator that the handover failed due to an LTM failure

[0244] - Target cell information where LTM attempt failed: LTM cell configuration index or actual cell index (PCI; Physical Cell Index) information

[0245] The source base station can know that the LTM attempt failed and the terminal fell back to the cell through a handover failure message report.

[0246] FIG. 9 is a block diagram illustrating the internal structure of a terminal to which the present disclosure is applied.

[0247] Referring to FIG. 9, a terminal according to one example of the present disclosure includes an RF (Radio Frequency) processing unit (1i-10), a baseband processing unit (1i-20), a storage unit (1i-30), and a control unit (1i-40).

[0248] The RF processing unit (1i-10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (1i-10) up-converts the baseband signal provided by the baseband processing unit (1i-20) into an RF band signal and 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 (1i-10) may include a transmit filter, a receive 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 (1i-10) may include multiple RF chains. Furthermore, the RF processing unit (1i-10) may perform beamforming. For the above beamforming, the RF processing unit (1i-10) can adjust the phase and magnitude of each of the signals transmitted and 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.

[0249] The baseband processing unit (1i-20) 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 (1i-20) generates complex symbols by encoding and modulating the transmitted bit sequence. Additionally, when receiving data, the baseband processing unit (1i-20) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (1i-10). For example, in the case of following the orthogonal frequency division multiplexing (OFDM) method, when transmitting data, the baseband processing unit (1i-20) generates complex symbols by encoding and modulating the transmitted bit sequence, maps the complex symbols to subcarriers, and then constructs OFDM symbols through inverse fast Fourier transform (IFFT) operations and cyclic prefix (CP) insertion. Additionally, upon receiving data, the baseband processing unit (1i-20) divides the baseband signal provided by the RF processing unit (1i-10) 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.

[0250] The baseband processing unit (1i-20) and the RF processing unit (1i-10) transmit and receive signals as described above. Accordingly, the baseband processing unit (1i-20) and the RF processing unit (1i-10) 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 (1i-20) and the RF processing unit (1i-10) 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 (1i-20) and the RF processing unit (1i-10) 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.

[0251] The storage unit (1i-30) stores data such as basic programs, application programs, and configuration information for the operation of the terminal. In particular, the storage unit (1i-30) can store information related to a second connection node that performs wireless communication using a second wireless connection technology. Additionally, the storage unit (1i-30) provides the stored data upon a request from the control unit (1i-40).

[0252] The control unit (1i-40) controls the overall operations of the terminal. For example, the control unit (1i-40) transmits and receives signals through the baseband processing unit (1i-20) and the RF processing unit (1i-10). Additionally, the control unit (1i-40) writes and reads data to and from the storage unit (1i-30). To this end, the control unit (1i-40) may include at least one processor. For example, the control unit (1i-40) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as applications.

[0253] FIG. 10 is a block diagram showing the configuration of a base station according to one example of the present disclosure.

[0254] Referring to FIG. 10, a base station according to one example of the present disclosure is configured to include an RF processing unit (1j-10), a baseband processing unit (1j-20), a backhaul communication unit (1j-30), a storage unit (1j-40), and a control unit (1j-50).

[0255] The RF processing unit (1j-10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (1j-10) up-converts the baseband signal provided by the baseband processing unit (1j-20) into an RF band signal and 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 (1j-10) may include a transmit filter, a receive 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. Additionally, the RF processing unit (1j-10) may include multiple RF chains. Furthermore, the RF processing unit (1j-10) may perform beamforming. For the above beamforming, the RF processing unit (1j-10) can adjust the phase and magnitude of each of the signals transmitted and received through a plurality of antennas or antenna elements. The RF processing unit can perform down-to-down MIMO operation by transmitting one or more layers.

[0256] The baseband processing unit (1j-20) 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 (1j-20) generates complex symbols by encoding and modulating the transmitted bit sequence. Additionally, when receiving data, the baseband processing unit (1j-20) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (1j-10). For example, in the case of following the OFDM method, when transmitting data, the baseband processing unit (1j-20) 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 (1j-20) divides the baseband signal provided by the RF processing unit (1j-10) 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 (1j-20) and the RF processing unit (1j-10) transmit and receive signals as described above. Accordingly, the baseband processing unit (1j-20) and the RF processing unit (1j-10) may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, a communication unit, or a wireless communication unit.

[0257] The backhaul communication unit (1j-30) provides an interface for communicating with other nodes within the network. That is, the backhaul communication unit (1j-30) 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.

[0258] The storage unit (1j-40) stores data such as basic programs, application programs, and configuration information for the operation of the main station. In particular, the storage unit (1j-40) can store information regarding bearers assigned to connected terminals, measurement results reported from connected terminals, etc. Additionally, the storage unit (1j-40) can store information serving as a criterion for determining whether to provide or disconnect multiple connections to the terminals. Furthermore, the storage unit (1j-40) provides the stored data upon the request of the control unit (1j-50).

[0259] The control unit (1j-50) controls the overall operations of the main station. For example, the control unit (1j-50) transmits and receives signals through the baseband processing unit (1j-20) and the RF processing unit (1j-10) or through the backhaul communication unit (1j-30). Additionally, the control unit (1j-50) writes and reads data to and from the storage unit (1j-40). To this end, the control unit (1h-50) may include at least one processor.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] In addition, the above program may be stored on an attachable storage device that can be accessed 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 a communication network may be connected to a device performing an embodiment of the present invention.

[0264] 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.

[0265] 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.

Claims

1. In a method of a terminal in a wireless communication system, A step of receiving a radio resource control (RRC) message from a base station comprising measurement resource configuration information for an LTM (layer 1 / layer 2 triggered mobility) candidate cell and report configuration information regarding an LTM measurement report—the report configuration information sets up an event-trigger-based measurement report and includes information regarding the time to trigger (TTT) associated with the event and information regarding the number of beams for which measurement results will be reported—; A step of measuring a plurality of beams for the candidate cell based on the above measurement resource setting information; and If a first beam satisfying the conditions of the event during the time corresponding to the TTT is identified among the plurality of beams, the method includes the step of transmitting an L1 measurement report MAC (medium access control) CE (control element) to the base station based on the report setting information. The above L1 measurement report MAC CE includes information regarding beams corresponding to the number of beams, and A method of a terminal characterized in that information regarding the beams includes a resource index related to a reference signal of the first beam and a measurement value of the first beam.

2. In Paragraph 1, The information regarding the beams further includes information regarding at least one second beam among the plurality of beams that does not satisfy the condition during the time corresponding to the TTT, and A method of a terminal characterized in that at least one second beam is selected based on the result of the measurement.

3. In Paragraph 1, A step of identifying a third beam among the plurality of beams that satisfies the conditions of the event; A step of verifying whether the measurement result for the third beam satisfies the condition during the time corresponding to the TTT; and A method of a terminal characterized by further including the step of restarting the time corresponding to the TTT for the third beam if the measurement result for the third beam does not satisfy the condition during the time corresponding to the TTT.

4. In Paragraph 1, The above event includes at least one event related to the signal strength of the serving cell beam, and A method of a terminal characterized by determining whether the condition of at least one event is satisfied based on the changed serving cell beam when the serving cell beam is changed while determining whether the condition is satisfied.

5. In Paragraph 1, The information regarding the above beams further includes information regarding the serving cell beam, and The above L1 measurement report MAC CE further includes a measurement report ID (identity) for the set event, and A method of a terminal characterized in that the above TTT is set for each event.

6. In the method of a base station in a wireless communication system, A step of transmitting a radio resource control (RRC) message to a terminal, the message including measurement resource setting information for an LTM (layer 1 / layer 2 triggered mobility) candidate cell and reporting setting information regarding an LTM measurement report - said reporting setting information sets up event-trigger-based reporting and includes information regarding the time to trigger (TTT) associated with the event and information regarding the number of beams for which measurement results will be reported -; and The method includes the step of receiving an L1 measurement report MAC (medium access control) CE (control element) from the terminal based on the report setting information, The above L1 measurement report MAC CE includes information regarding beams corresponding to the number of beams, and A method of a base station characterized by the information regarding the beams including a resource index associated with a reference signal of a first beam that satisfies the conditions of the event during the time corresponding to the TTT, and a measured value of the first beam.

7. In Paragraph 6, The information regarding the beams further includes information regarding at least one second beam among the plurality of beams that does not satisfy the condition during the time corresponding to the TTT, and A method of a base station characterized in that at least one second beam is selected based on the result of the measurement.

8. In Paragraph 6, The information regarding the above beams further includes information regarding the serving cell beam, and The above L1 measurement report MAC CE further includes a measurement report ID (identity) for the event, and The above TTT is a method of a base station characterized by being set for each event.

9. In a terminal of a wireless communication system, Transmitter / receiver; and A control unit comprising: receiving a radio resource control (RRC) message from a base station that includes measurement resource setting information for an LTM (layer 1 / layer 2 triggered mobility) candidate cell and report setting information regarding an LTM measurement report; wherein the report setting information sets up an event-trigger-based measurement report and includes information regarding the time to trigger (TTT) associated with the event and information regarding the number of beams for which measurement results will be reported; measuring a plurality of beams for the candidate cell based on the measurement resource setting information; and, when a first beam satisfying the conditions of the event for a time corresponding to the TTT is identified among the plurality of beams, transmitting an L1 measurement report MAC (medium access control) CE (control element) to the base station based on the report setting information. The above L1 measurement report MAC CE includes information regarding beams corresponding to the number of beams, and A terminal characterized in that information regarding the beams includes a resource index related to a reference signal of the first beam and a measurement value of the first beam.

10. In Paragraph 9, The information regarding the beams further includes information regarding at least one second beam among the plurality of beams that does not satisfy the condition during the time corresponding to the TTT, and A terminal characterized in that at least one second beam is selected based on the result of the measurement.

11. In Paragraph 9, A terminal characterized in that the control unit identifies a third beam among the plurality of beams that satisfies the conditions of the event, checks whether the measurement result for the third beam satisfies the conditions during the time corresponding to the TTT, and if the measurement result for the third beam does not satisfy the conditions during the time corresponding to the TTT, restarts the time corresponding to the TTT for the third beam.

12. In Paragraph 9, The above event includes at least one event related to the signal strength of the serving cell beam, and A terminal characterized in that the control unit determines whether the condition of at least one event is satisfied based on the changed serving cell beam when the serving cell beam is changed while determining whether the condition is satisfied.

13. In a base station of a wireless communication system, Transmitter / receiver; and A control unit comprising a terminal, which transmits a radio resource control (RRC) message including measurement resource setting information for an LTM (layer 1 / layer 2 triggered mobility) candidate cell and reporting setting information regarding an LTM measurement report, wherein the reporting setting information sets up event-trigger-based reporting and includes information regarding the time to trigger (TTT) associated with the event and information regarding the number of beams for which measurement results will be reported, and receives an L1 measurement report MAC (medium access control) CE (control element) from the terminal based on the reporting setting information, The above L1 measurement report MAC CE includes information regarding beams corresponding to the number of beams, and A base station characterized by the information regarding the beams including a resource index related to a reference signal of a first beam that satisfies the conditions of the event during the time corresponding to the TTT, and a measured value of the first beam.

14. In Paragraph 13, The information regarding the beams further includes information regarding at least one second beam among the plurality of beams that does not satisfy the condition during the time corresponding to the TTT, and A base station characterized in that at least one second beam is selected based on the result of the measurement.

15. In Paragraph 13, The information regarding the above beams further includes information regarding the serving cell beam, and The above L1 measurement report MAC CE further includes a measurement report ID (identity) for the event, and The above TTT is a base station characterized by being set for each event.

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