Method and device for supporting cell measurement result report of terminal in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a user equipment (UE) may comprise the steps of: receiving configuration information for a first measurement report from a base station, the configuration information including information on an event triggering the first measurement report; if a leaving condition applied to the event is fulfilled for at least one cell, and entering leaving report information is included in the configuration information, storing the at least one cell in a list of cells fulfilling the leaving condition; and transmitting the first measurement report including the list to the base station.

Description

Method and device for supporting reporting of cell measurement results of a terminal in a wireless communication system

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and device for supporting AI / ML-based mobility in a mobile communication system.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0005] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) that simplifies random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] According to one embodiment of the present disclosure, a device and method for effectively providing a service in a mobile communication system are provided.

[0009] According to one embodiment of the present disclosure, a method performed by a user equipment (UE) may include the steps of: receiving, from a base station, configuration information for a first measurement report, the configuration information including information about an event that triggers the first measurement report; storing, when a leaving condition applied to the event is fulfilled for at least one cell and entering leaving report information is included in the configuration information, the step of: storing the at least one cell in a list of cells satisfying the leaving condition; and transmitting, to the base station, the first measurement report including the list.

[0010] According to one embodiment of the present disclosure, a device and method for effectively providing a service in a wireless communication system can be provided.

[0011] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0012] FIG. 1 is a diagram illustrating the structure of a mobile communication system according to one embodiment of the present disclosure.

[0013] FIG. 2 is a diagram for explaining a wireless connection state transition in a mobile communication system according to an embodiment of the present disclosure.

[0014] FIG. 3 is a diagram illustrating a process in which a terminal performs cell measurement and reporting operations according to an embodiment of the present disclosure.

[0015] FIG. 4 is a diagram illustrating an operation of a terminal reporting a cell measurement result when the reporting condition of the cell measurement result is satisfied according to an embodiment of the present disclosure.

[0016] FIG. 5 is a diagram illustrating an operation of a terminal reporting cell measurement results that change over time to a base station according to an embodiment of the present disclosure.

[0017] FIG. 6 is a diagram illustrating a process in which a terminal performs enhanced cell measurement and reporting operations according to an embodiment of the present disclosure.

[0018] FIG. 7 is a diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0019] FIG. 8 is a diagram illustrating the structure of a base station according to one embodiment of the present disclosure.

[0020] The operating principles of the present disclosure are described in detail below with reference to the attached drawings. In the following description of the present disclosure, detailed descriptions of known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present invention. Furthermore, the terms described below are defined based on their functions in the present invention and may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0021] An embodiment of the present invention is described below with reference to the attached drawings.

[0022] In the following description, terms used to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, and / or terms referring to various identification information are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0023] For convenience of explanation, the present invention uses terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard. However, the present disclosure is not limited to the above-described terms and names, and can be equally applied to systems conforming to other standards. In the present disclosure, the term eNB (evolved Node B) may be used interchangeably with gNB (next generation Node B) for convenience of explanation. For example, a base station described as an eNB may be replaced with a gNB.

[0024] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. However, the embodiments are provided to ensure that the description of the present disclosure is complete and to fully inform those skilled in the art of the scope of the invention. The claimed scope of the present disclosure is defined solely by the scope of the claims.

[0025] At this time, it can be understood that each block of the drawings showing the processing flowchart and the combination of the processing flowchart drawings can be performed by computer program instructions. The computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed through the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). The computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement a function in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can produce a manufactured item including an instruction means for performing the functions described in the flowchart block(s). Computer program instructions may also be installed on a computer or other programmable data processing device, so that a series of operational steps may be performed on the computer or other programmable data processing device, and instructions that generate a computer-executable process and cause the computer or other programmable data processing device to perform may provide steps for performing the functions described in the flowchart block(s).

[0026] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0027] The term 'unit or part' used in this disclosure means a software or hardware component such as a field-programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and the 'unit' may be configured to perform specific roles. However, the 'unit' is not limited to software or hardware. The 'unit' may be configured to reside in an addressable storage medium and may be configured to execute one or more processors. Thus, as an example, the 'unit' may include components such as software components, object-oriented software components, class components, and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and / or variables. The functionality provided within the components and 'units' may be combined into a smaller number of components and 'units' or further separated into additional components and 'units'. Additionally, the components and '~parts' may be implemented to play one or more central processing units (CPUs) within the device or secure multimedia card. Furthermore, in an embodiment, the '~parts' may include one or more processors and / or devices.

[0028] For convenience of explanation below, some terms and names defined in communication standards based on 3GPP (3rd Generation Partnership Project Long Term Evolution) (e.g., standards for 5G (fifth-generation), NR (new radio), LTE (long term evolution), or similar systems) may be used. However, the present disclosure is not limited by the terms and names, and may be equally applied to systems conforming to other standards.

[0029] The 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 objects, or terms referring to various identification information are provided for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0030] In specifically describing the embodiments of the present disclosure, the New RAN (NR), which is a wireless access network, and the Packet Core (5G System, or 5G Core Network, or NG Core: Next Generation Core), which is a core network, based on the 5G mobile communication standard specified by 3GPP, a mobile communication standard standardization organization, will be mainly described. However, the main gist of the present disclosure can also be applied to other communication systems having a similar technical background. For example, the main gist of the present disclosure can be applied with slight modifications within a range that does not significantly deviate from the scope of the present disclosure, and this will be possible at the discretion of a person skilled in the art of the present disclosure.

[0031] FIG. 1 is a diagram illustrating the structure of a mobile communication system according to one embodiment of the present disclosure.

[0032] Referring to FIG. 1, a wireless access network of a mobile communication system (e.g., New Radio, NR) according to an embodiment of the present disclosure may be composed of a base station (next generation Node B, hereinafter referred to as gNB) (1-10) and an AMF (1-05, New Radio Core Network). For example, the AMF (1-05) may be an AMF (access and mobility management function) entity.

[0033] According to one embodiment of the present disclosure, a user terminal (New Radio User Equipment, hereinafter referred to as NR UE or terminal) (1-15) can access an external network through a gNB (1-10) and an AMF (1-05).

[0034] According to one embodiment of the present disclosure, the mobile communication system may be a next-generation mobile communication system, and the base station may be a next-generation base station. However, the present disclosure is not limited thereto, and the mobile communication system may be at least one of NR, LTE, 3G (generation), or 2G.

[0035] According to one embodiment, the gNB (1-10) in FIG. 1 may correspond to an Evolved Node B (eNB) (or, an evolved universal terrestrial radio access network (E-UTRAN) node B) of an existing long-term evolution (LTE) system. The gNB (1-10) is connected to an NR UE via a wireless channel and may provide a service superior to that of an existing Node B (1-20). In the next-generation mobile communication system according to one embodiment of the present disclosure, since all user traffic is serviced through a shared channel, a device that collects state information such as buffer states of UEs, available transmission power states, and / or channel states and performs scheduling may be required. The collecting of state information and scheduling may be performed by the gNB (1-10).

[0036] According to one embodiment, a single gNB (1-10) can generally control multiple cells. Next-generation mobile communication systems can support bandwidths higher than the existing maximum bandwidth to implement ultra-high-speed data transmission. In the next-generation mobile communication system, beamforming technology can be additionally incorporated with orthogonal frequency division multiplexing (OFDM) as a wireless access technology. In addition, the next-generation mobile communication system can apply an adaptive modulation and coding (AMC) method that determines a modulation scheme and channel coding rate according to the channel condition of the terminal.

[0037] According to one embodiment, in FIG. 1, the AMF (1-05) may perform functions such as mobility support, bearer setup, and / or quality of service (QoS) setup. For example, the AMF (1-05) may be a device that is responsible for various control functions as well as mobility management functions for a terminal and may be connected to multiple base stations. In addition, the mobile communication system according to one embodiment of the present disclosure may also be interoperable with an LTE system. For example, the AMF (1-05) may be connected to the MME (1-25) via a network interface. For example, evolved universal terrestrial radio access network (E-UTRAN)-NR dual connectivity (EN-DC) may be implemented in the mobile communication system.

[0038] According to one embodiment, the MME (1-25) may be connected to an existing base station, eNB (1-30). For example, in FIG. 1, a terminal supporting LTE-NR Dual Connectivity can transmit and receive data while maintaining connection to both the gNB (1-10) and the eNB (1-30) (1-35).

[0039] FIG. 2 is a diagram for explaining a wireless connection state transition in a mobile communication system according to an embodiment of the present disclosure.

[0040] According to one embodiment of the present disclosure, in a mobile communication system, a terminal may have three radio connection states (RRC (radio resource control) states) or RRC modes. For example, the terminal may have RRC_CONNECTED, RRC_IDLE, and RRC_INACTIVE states.

[0041] According to FIG. 2, the connected mode (RRC_CONNECTED, 2-05) may be a wireless connection state in which the terminal can transmit and / or receive data. Additionally, the standby mode (RRC_IDLE, 2-30) may correspond to a wireless connection state in which the terminal monitors whether paging is being transmitted to itself. For example, the two modes (e.g., RRC_CONNECTED, RRC_IDLE) may be wireless connection states applicable to the LTE system, and the specific techniques may be substantially the same as those of the LTE system. A mobile communication system according to an embodiment of the present disclosure may be a next-generation mobile communication system.

[0042] According to one embodiment of the present disclosure, a new inactive (RRC_INACTIVE) radio connection state (2-15) may be defined in a mobile communication system. For example, in the radio connection state (2-15) (e.g., RRC_INACTIVE), UE context may be maintained between the base station and the terminal, and RAN (radio access network)-based paging may be supported. The characteristics of the new radio connection state (2-15) may include at least one of the following:

[0043] - Cell re-selection mobility;

[0044] - CN (core network) - NR RAN connection (both C / U-planes (control plane / user plane)) has been established for UE;

[0045] - The UE AS(Access Stratum) context is stored in at least one gNB and the UE;

[0046] - Paging is initiated by NR RAN;

[0047] - RAN-based notification area is managed by NR RAN;

[0048] - NR RAN knows the RAN-based notification area which the UE belongs to;

[0049] According to one embodiment of the present disclosure, a terminal in an INACTIVE wireless connection state (2-15) can use a specific procedure to transition to a connected mode (2-05) or a standby mode (2-30). The terminal can transition from the INACTIVE mode (2-15) to the connected mode (2-05) using an RRC Resume procedure, and can transition from the connected mode (2-05) to the INACTIVE mode (2-15) using a Release procedure including suspend configuration information (2-10). For example, a specific procedure (e.g., RRC resume, RRC release) can be performed by transmitting and / or receiving one or more RRC messages between the terminal and the base station, and can consist of one or more steps. In addition, according to one embodiment, a transition from the INACTIVE mode (2-15) to the standby mode (2-30) can be possible through a Release procedure after Resume (2-20). Switching between connected mode (2-05) and standby mode (2-30) can be performed according to LTE technology. Furthermore, according to FIG. 2, switching between the modes can be accomplished through an establishment or release procedure (2-25).

[0050] FIG. 3 is a diagram illustrating a process in which a terminal performs cell measurement and reporting operations according to one embodiment of the present disclosure.

[0051] According to one embodiment of the present disclosure, in step 3-15, the terminal (3-05) may report its capability information (e.g., UE capability information) to the base station or network (3-10). For example, the terminal (3-05) may report cell measurement (or measurement or measurement) related capabilities to the base station or network.

[0052] According to one embodiment, in step 3-20, the base station (3-10) may transmit a message (e.g., an RRC Reconfiguration message or an RRC Resume message, etc.) containing configuration information (e.g., MeasConfig IE (information element)) related to cell measurement (or measurement or measurement) operation (e.g., based on capability information of the received terminal) to the terminal (3-05). (RRCReconfiguration (MeasConfig))

[0053] According to one embodiment, the configuration information may include information related to “measurement objects” that can indicate radio resource information on which the terminal (3-05) is to perform measurements (e.g., via MeasObjectNR IE in MeasConfig). For example, the information related to each measurement object may indicate information on the frequency domain location and / or time domain location of a reference signal (e.g., synchronization signal block (SSB) or channel state information (CSI)-reference signal (RS)) on which the terminal (3-05) is to perform measurements, and / or subscarrier spacing (SCS) information. According to one embodiment, the information related to each measurement object (e.g., MeasObjectNR) may be indicated and / or identified by a specific identity (ID) (e.g., MeasObjectId).

[0054] In one embodiment, the configuration information may include information related to “reporting configurations” that indicate settings related to measurement reporting of the terminal (3-05) (e.g., via a ReportConfigNR IE in MeasConfig). For example, the information related to reporting configurations may indicate whether the terminal (3-05) should periodically perform measurement reports and / or whether measurement reports are triggered when a specific event occurs. For example, the information related to reporting configurations may indicate a reference signal that the terminal (3-05) will use for measurement and / or reporting. For example, the information related to reporting configurations (e.g., ReportConfigNR) may be indicated and / or identified by a specific identity (e.g., ReportConfigId).

[0055] According to one embodiment, cell measurement configuration information (e.g., MeasConfig) may include information related to a plurality of measurement objects (e.g., MeasObjectNR) and information related to a plurality of report configurations (e.g., ReportConfigNR). Information related to a specific measurement object may be associated with information related to a specific report configuration. For example, cell measurement configuration information may include information related to a first measurement object, information related to a second measurement object, ..., information related to an n-th measurement object, and cell measurement configuration information may include information related to a first report configuration, information related to a second report configuration, ..., information related to an n-th report configuration. In this case, information related to the first measurement object may be mapped or correspond to information related to the first report configuration.

[0056] According to one embodiment, the cell measurement configuration information may include a linkage ID (e.g., MeasId) for indicating / identifying a linkage between an ID of a measurement object (e.g., MeasObjectId) and an ID of a report configuration (e.g., ReportConfigId). In this case, the terminal (3-05) may perform measurements and reports based on the corresponding measurement objects and linked report configurations. For example, a first linkage ID may be mapped to an ID of a first measurement object and an ID of a first report configuration, and when the terminal (3-05) receives information about the first linkage ID, it may perform measurements for the first measurement object based on the first report configuration.

[0057] According to one embodiment, the reporting configuration (e.g., ReportConfigNR) in the configuration information (e.g., MeasConfig IE) may include information necessary for the terminal to report the measurement results to the base station. For example, the reporting configuration in the configuration information may include information on the terminal's report type or reporting method. For example, if the reportType in ReportConfigNR is indicated as periodical, the terminal may periodically transmit the measurement results to the base station through the configuration information (e.g., MeasConfig). For example, if the reportType in ReportConfigNR is eventTriggered, the terminal (3-05) may report the measurement results to the base station (3-10) when a specific Event configured based on the configuration information is satisfied (more specifically, when an entering condition or a leaving condition of a specific Event is satisfied). For example, in the NR system, at least one of the following Events may be configured. For example, the terminal (3-05) may be configured with at least one of the following Events.

[0058] In relation to one embodiment, Events related to intra- / inter-RAT (radio access technology) measurements can be exemplified in [Table 1] below.

[0059]

[0060] According to one embodiment, similar to condition-based measurement reporting, in condition-based handover, when a specific event is satisfied, the terminal (3-05) can perform a handover according to condition-based handover configuration information. Events related to condition-based handover can be exemplified in [Table 2] below.

[0061]

[0062] According to one embodiment, when a specific event is satisfied in the Sidelink Relay, the terminal (3-05) can perform a specific action.

[0063] Events related to Relay, related to one embodiment, can be exemplified in [Table 3].

[0064]

[0065] According to one embodiment, even in the case of NR-U (Unlicensed), when a specific event is satisfied, the terminal (3-05) can perform a specific action.

[0066] Events related to NR-U in connection with one embodiment can be exemplified in [Table 4].

[0067]

[0068] According to one embodiment of the present disclosure, if the entering condition or leaving condition of the previously exemplified Events is continuously satisfied for a specific time period (time-to-trigger), the terminal (3-05) can initiate or trigger a Measurement report transmission operation for the aforementioned Event. However, if the leaving condition is satisfied for a specific Event, the terminal (3-05) can initiate (trigger) a Measurement report transmission operation only when the reportOnLeave directive is additionally included in the measurement setting for the corresponding Event in step 3-20.

[0069] According to FIG. 3, in step 3-25, the terminal (3-05) can perform measurements based on the measurement settings, and when the set conditions are satisfied, the terminal (3-05) can report a message (e.g., MeasurementReport) containing the measurement results to the base station (3-10) (step 3-30). Alternatively, the terminal (3-05) can perform a terminal operation corresponding to the conditions (e.g., condition-based handover). (MR triggering condition check)

[0070] According to one embodiment, the base station (3-10) that receives the measurement result can use the measurement result for a specific purpose. For example, in step 3-35, based on the result, the base station (3-10) can decide whether to hand over the terminal (3-05) (or to set up a condition-based handover). Initiating (C)HO progress According to one embodiment, when the base station (3-10) triggers a handover, the base station (3-10) can request the handover (or condition-based handover) to the target cell in step 3-40. (C)HO coordination with the target(s) In addition, in step 3-45, the base station (3-10) can transmit handover (or condition-based handover) setting information configured based on the setting information received from the target cell to the terminal (3-05). According to one embodiment, in step 3-50, the terminal (3-05) that has received configuration information (e.g., handover configuration information) can perform handover based on the configuration information. RRCReconfiguration (ReconfigurationWithSync)

[0071] Referring to Figure 3, even after step 3-50, the terminal can continue to perform measurements according to the measurement settings in steps 3-20 and 3-45 (executing HO). In step 3-55, the terminal (3-05) can check or identify whether the measurement report transmission start (triggering) condition has been satisfied, as in step 3-25, based on the measurement performance results (MR triggering condition check).

[0072] For example, if the condition is satisfied, in step 3-60, the terminal (3-05) can report a message (e.g., MeasurementReport) containing the measurement result to the base station (3-10). For example, the base station (3-10) that receives the measurement result can use the measurement result for a specific purpose. For example, in step 3-65, based on the measurement result, the base station (3-10) can update the handover setting (or condition-based handover setting) in step 3-45. For example, in step 3-45, the base station (3-10) can set a condition-based handover for a specific cell A to the terminal (3-05). However, in step 3-60, the base station (3-10) can identify that the specific cell A is no longer a suitable target cell for the condition-based handover based on the measurement result in the Measurement Report transmitted by the terminal (3-05). At step 3-65, the base station (3-10) can cancel the condition-based handover configuration for cell A and transmit the handover configuration to a new cell to the terminal (3-05) through the RRCReconfiguration procedure. (Procedure to update (C)HO configuration based on the latest measurement report)

[0073] FIG. 4 is a diagram illustrating an operation of reporting cell measurement results when a terminal satisfies a reporting condition of cell measurement results according to an embodiment of the present disclosure.

[0074] FIG. 4 may relate to an operation of a terminal reporting a cell measurement result when a reporting condition of a cell measurement result is satisfied according to an embodiment of the present disclosure.

[0075] According to one embodiment of the present disclosure, the terminal (4-10) can evaluate the signal strength (e.g., reference signal received power (RSRP)) and / or quality (e.g., reference signal received quality (RSRQ)) of a cell signal operated by the base station (4-05) based on a signal (e.g., synchronization signal block (SSB) or channel state information reference signal (CSI-RS)) that can be transmitted from the base station (4-05). For example, the terminal (4-10) can identify a signal having the highest strength among the signals received from the base station (4-05) or identify signals having a strength greater than a threshold value.

[0076] For convenience of explanation, the cell measurement result reporting operation of the terminal may be explained mainly with SSB as an example, but the same may be applied to DMRS (Demodulation reference signals) and / or CSI-RS, etc.

[0077] According to one embodiment, in the case of SSB, the transmission cycle of SSB may be determined according to the settings of the base station (4-05). For example, the transmission cycle of SSB may be set to 20 ms, and the base station (4-05) may transmit SSB at a cycle of up to 160 ms. However, the numerical contents are merely examples, and the present disclosure is not limited thereto.

[0078] According to one embodiment, referring to FIG. 4, when a base station (4-05) sets a specific event (e.g., Event A4) to a terminal (4-10), the terminal (4-10) can determine whether an entering condition and / or a leaving condition for the event is satisfied based on the RSRP (reference signals received power) value measured based on SSB, and can start or trigger a cell measurement reporting operation.

[0079] According to one embodiment, the terminal (4-10) can identify (or evaluate) whether the RSRP value measured based on SSB is continuously higher than a threshold value (4-35, A4-Threshold plus a Hysteresis value) for a specific time period (time-to-trigger, TTT) from the time point (4-15) when the RSRP value of a specific cell measured based on SSB becomes higher than the threshold value. For example, the Hysteresis value may be a deviation value applied to a set threshold value, or a value for dynamically changing the threshold value. For example, the Hysteresis value may be preset by the base station.

[0080] In one embodiment, if the RSRP value measured from the initial time point (4-15) when the RSRP value measured based on SSB is higher than the threshold value (4-35) to the time point (4-20) when the time interval has elapsed is higher than (or higher than or equal to) the threshold value, the terminal (4-10) may determine that the entering condition for the Event A4 exemplified above has been satisfied. Since the measurement report condition for Event A4 has been satisfied, the terminal may report a measurement report triggered by the Event A4 to the base station (4-05). As another example, if the average (or maximum value) of the RSRP values ​​measured from the initial time point (4-15) to the time point (4-20) when the time interval has elapsed is higher than the threshold value, the entering condition may be determined to have been satisfied. As another example, the entry condition may be determined to be satisfied if the RSRP value measured for at least some period from the initial point in time (4-15) to the time interval elapsed (4-20) is higher than the threshold value.

[0081] According to one embodiment, the terminal (4-10) can identify (or evaluate) whether the RSRP value measured based on SSB is continuously lower than the threshold for a specific time period (time-to-trigger, TTT) from the time point (4-25) when the RSRP value of a specific cell measured based on SSB becomes lower than a specific threshold (4-40, A4-Threshold minus the Hysteresis value).

[0082] According to one embodiment, if the RSRP value measured from the initial time point (4-25) when the RSRP value measured based on SSB is lower than the threshold value (4-40) to the time point (4-30) when the time interval has elapsed is lower than (or lower than or equal to) the Threshold, the terminal (4-10) may determine that the leaving condition for the exemplified Event A4 has been satisfied. Additionally, if the ReportOnLeave indicator is set for Event A4 (i.e., the terminal is set to report the measurement result when the leaving condition for the corresponding event is satisfied), the terminal may report a measurement report triggered by the Event A4 to the base station (4-05) because the measurement reporting condition has been satisfied. As another example, if the average (or maximum value) of the RSRP values ​​measured from the initial time point (4-25) to the time point (4-30) when the time interval has elapsed is lower than the threshold value, the entry condition may be determined to have been satisfied. As another example, the entry condition may be determined to be satisfied if the RSRP value measured for at least some period from the initial point in time (4-25) to the time interval elapsed (4-30) is lower than the threshold value.

[0083] According to one embodiment, the reason why TTT is considered in determining whether the conditions for performing a measurement report are satisfied may be to compensate for the variability of the measurement signal. In addition, the TTT value may be set by the base station (4-05) to the terminal (4-10) for each specific Event that is set. According to one embodiment, if the Events that can be exemplified continuously satisfy a specific condition for a specific time period (TTT), the terminal operation corresponding to the purpose of the set Event may be performed.

[0084] According to one embodiment, if the reportType in the measurement-related setting information received by the terminal (4-10) is periodical or eventTriggered, the terminal (4-10) can perform a measurement report periodically.

[0085] The terminal (4-10) of FIG. 4 of the present disclosure may correspond to the terminal (3-05) of FIG. 3, and the base station (4-05) may correspond to the base station (3-10) of FIG. 3. Accordingly, the embodiments of FIG. 3 and FIG. 4 may be combined as long as they are not contradictory.

[0086] FIG. 5 is a diagram illustrating an operation in which a terminal reports cell measurement results that change over time to a base station according to an embodiment of the present disclosure.

[0087] Referring to FIG. 5, the terminal (5-05) can determine whether the entering condition and leaving condition for a specific event are satisfied as described in FIG. 4 described above and can start or trigger a cell measurement reporting operation.

[0088] According to one embodiment, the base station (5-10) may pre-configure the terminal (5-05) to perform a cell measurement reporting operation for a specific event. At this time, the configuration information may include information on the maximum number of cells (e.g., MaxReportCells) that can include measurement information in the measurement report when the terminal transmits the measurement report. This embodiment shows a case where the base station sets the MaxReportCells value to '2' when configuring the cell measurement and reporting operation for the terminal. However, this is only an example, and the maximum number may be 2 or more.

[0089] At time T1 (5-15), the terminal (5-05) can identify that an entering condition for a specific Event (e.g., Event A4) has been satisfied during the Time To Trigger (TTT) for Cell A, Cell B, and / or Cell C. The terminal can include cells that have satisfied the entering condition for the Event during the TTT in the cellsTriggeredList for the Event.

[0090] For example, the terminal (5-05) can transmit a Measurement report to the base station (5-10) when the conditions for transmitting a Measurement report for an Event are satisfied. The terminal (5-05) can include cell measurement information for up to two cells in the Measurement report (5-20) based on the MaxReportCells value set to '2'. For example, the terminal (5-05) can select or identify two cells (e.g., A and B) to be reported in the order of good signal strength among the cells included in the cellsTriggeredList for the Event. For example, the terminal (5-05) can include the measurement results for the cells (e.g., A and B) in measResultNeighCells in the Measurement report. (MaxReportCells is configured as '2') (MeasurementReport with measResultNeighCells for Cell A & Cell B)

[0091] According to one embodiment, at time T2 (5-25), the base station (5-10) may perform a handover setup for the terminal (5-05) based on the measurement report (5-20) received from the terminal (5-05) at time T1. For example, the base station (5-10) may set a conditional handover (CHO) for the terminal (5-05) to a cell (e.g., cell A, cell B) included in the measurement report transmitted by the terminal (5-05) at time T1.

[0092] According to one embodiment, at time T3 (5-35), the terminal (5-05) can identify that the entering condition and leaving condition for a specific event (e.g., Event A4) have been satisfied during the Time To Trigger (TTT). The terminal can include cells that have satisfied the entering condition for the event during the TTT in the cellsTriggeredList for the event. Conversely, the terminal can remove cells that have satisfied the leaving condition for the event during the TTT from the cellsTriggeredList for the event.

[0093] For example, if the conditions for transmitting a Measurement report for an Event are satisfied, the terminal (5-05) can transmit a Measurement report to the base station (5-10). The terminal (5-05) can include cell measurement information for up to two cells in the Measurement report (5-40) based on the MaxReportCells value set to '2'. For example, the terminal (5-05) can select or identify two cells (e.g., A and C) to be reported in the order of good signal strength among the cells included in the cellsTriggeredList for the Event. The terminal can include the measurement results for the cells (e.g., A and C) in measResultNeighCells in the Measurement report. (MeasurementReport with measResultNeighCells for Cell A & Cell C)

[0094] According to one embodiment, the terminal (5-05) can transmit a measurement report including measurement results for A and C to the base station (5-10) in both of the following cases.

[0095] Case 1 (When the entering condition is satisfied for Cell A, C, B): If the Event A4 entering condition is satisfied for Cell A, C, and B during the TTT, the terminal (5-05) can include all of the cells in the cellsTriggeredList. Afterwards, the terminal can select two cells (e.g., A, C) to be reported in the order of good signal strength among the cells included in the cellsTriggeredList and include them in the measurement report (5-40). For reference, at time T3, unlike time T1, the signal strengths of cells A, C, and B are good in that order, so cells A and C can be selected.

[0096] Case 2 (When the entering condition is satisfied for Cell A, C and the leaving condition is satisfied for Cell B): If the Event A4 entering condition is satisfied for Cell A and C during the TTT, the terminal (5-05) can include all cells (e.g., A, C) in the cellsTriggeredList. In addition, if the Event A4 leaving condition is satisfied for Cell B during the TTT, the terminal (5-05) can remove the cell (e.g., Cell B) from the cellsTriggeredList. Thereafter, the terminal can select two cells (e.g., A, C) to be reported in the order of good signal strength among the cells included in the cellsTriggeredList and include them in the measurement report (5-40). For reference, at time T3, unlike time T1, only Cell A and C satisfy the entering condition for the Event, so only Cell A and C can be selected.

[0097] In one embodiment, when the base station (5-10) receives a measurement report (5-40) including measurement results for Cell A and C from the terminal (5-05), the base station (5-10) cannot determine which of the two cases (e.g., Case 1 and Case 2) described above corresponds to the case in which the terminal (5-05) transmitted the measurement report. Therefore, the base station (5-10) cannot make an appropriate handover decision based on the measurement report. For example, the base station (5-10) may have difficulty making a judgment on the issues described below.

[0098] - Issue 1: Did Cell C satisfy the entering condition for the first time at time T3 (5-35) or did it already satisfy the entering condition at time T1 (5-20) but not report because the signal strength was worse than that of Cells A and B?

[0099] - Issue 2: At time T3 (5-35), whether Cell B was not reported because it met the leaving condition or because its signal strength was worse than that of Cells A and C.

[0100] In one embodiment, if the base station (5-10) determines that the reason Cell B was not reported at time T3 for Issue 2 is because Cell B satisfies the leaving condition of Event A4, the base station (5-10) may cancel the condition-based handover configuration set for Cell B at time T2. As another example, if the base station (5-10) determines that the reason Cell B was not reported at time T3 for Issue 2 is because the signal strength of Cell B is worse than that of Cells A and C, the base station (5-10) may add the condition-based handover configuration for Cell C while maintaining the condition-based handover configuration for Cell B. Therefore, in order for the base station (5-10) to make an appropriate handover decision for the terminal (5-05), the base station (5-10) must be able to make the correct judgment on the issues based on the measurement report transmitted from the terminal (5-05). For example, the base station (5-10) may need to identify the reason why cells were not reported.

[0101] However, as in the above-described embodiment, the information currently included in the measurement report may not be sufficient for the base station to make the correct handover decision. Figure 6 below describes an embodiment for improving the operation of a terminal triggering a measurement report and the information included in the measurement report to assist the base station in making the correct handover decision.

[0102] FIG. 6 is a diagram illustrating a process in which a terminal performs enhanced cell measurement and reporting operations according to an embodiment of the present disclosure.

[0103] Steps 6-15 are described below.

[0104] According to one embodiment, in step 6-20, the base station (6-10) may transmit measurement configuration (e.g., MeasConfig) to the terminal via an RRC Reconfiguration message or an RRC Resume message. Report configuration (e.g., ReportConfigNR) within the measurement configuration may include a periodic report configuration (e.g., PeriodicalReportConfig) and an event-based report configuration (e.g., EventTriggerConfig) as a report type (e.g., reportType).

[0105] According to one embodiment, regardless of the report type, configuration information such as the type of reference signal to be measured (e.g., RS (reference signal) type), the reporting time interval (e.g., reportInterval), the number of reports (e.g., reportAmount), and / or the maximum number of neighboring cells to report (e.g., maxReportCells) may be commonly included in the periodic reporting configuration and the event-based reporting configuration. For example, each event-based reporting configuration (e.g., EventTriggerConfig) may include directives such as reportOnLeave, reportOnBestCellChange, and / or enteringLeavingReport for configuring enhanced measurement reporting behavior. The configuration information may be configured as shown in [Table 5] below, and specific terminal operations based thereon are as described in steps 6-25 below.

[0106]

[0107] According to one embodiment, in step 6-25, the terminal (5-05) may perform measurements according to the measurement settings (e.g., MeasConfig) provided by the base station (5-10) in step 6-20, initiate or trigger a measurement report procedure, and set (or configure) information to be included in the measurement report. MR triggering & setting

[0108] According to one embodiment of the present disclosure, when the base station (6-10) sets periodic reporting to the terminal (6-05) in step 6-20, the terminal (6-05) can trigger the transmission of measurement reports repeatedly by the number of reportAmount at a periodic interval of reportInterval according to the settings included in the periodic reporting settings (e.g., PeriodicalReportConfig).

[0109] In one embodiment of the present disclosure, when the base station (6-10) configures an event-based report to the terminal (6-05) in step 6-20, the terminal (6-05) can identify (or evaluate) whether an entering condition for an event is satisfied and / or a leaving condition is satisfied based on a specific event configuration (e.g., eventAx) included in the event-based report configuration (e.g., EventTriggerConfig). For example, the terminal (6-05) can determine whether an entering condition and / or a leaving condition defined for event A4 is satisfied as shown in [Table 6] below.

[0110]

[0111] According to one embodiment of the present disclosure, the terminal (6-05) can check or identify whether an entering condition for a specific event is satisfied based on the reporting configuration (e.g., ReportConfigNR) set in step 6-20. The terminal (6-05) can trigger a measurement reporting procedure if the entering condition for the event is satisfied for one or more cells during the TTT. At this time, the terminal (6-05) can include cells that have satisfied the entering condition in the cellsTriggeredList within the VarMeasReportList for the reporting configuration (more specifically, for the measId linked to the reporting configuration). The operation of the terminal (6-05) can be described as shown in [Table 7] below.

[0112]

[0113] In one embodiment of the present disclosure, the terminal (6-05) can check or identify whether a leaving condition for a specific Event is satisfied based on the reporting configuration (e.g., ReportConfigNR) set in step 6-20. For example, the leaving condition for the Event may be satisfied for one or more cells during the TTT. In this case, the terminal (6-05) can store (or include) cells for which the condition is satisfied in cellsMetLeavingCond in VarMeasReportList (more specifically, for the measId linked to the reporting configuration) for the reporting configuration and remove (or delete) them from cellsTriggeredList. Additionally, the terminal (6-05) can trigger a measurement reporting procedure if the reportOnLeave directive in the reporting configuration is set to 'true' (e.g., if the directive has a specified value). Thereafter, all cells included in cellsMetLeavingCond can be deleted (or removed) again. The operation of the terminal (6-05) can be explained as shown in [Table 8] below.

[0114]

[0115] As described above, when the measurement reporting procedure is started (e.g., triggered), the terminal (6-05) can include measurement results for neighboring cells up to maxReportCells in the measurement report. (Note that the maxReportCells value here is the value set by the base station to the terminal in step 6-20.) If the event-based reporting (e.g., EventTriggered) is set as the report type (e.g., reportType) in the report configuration (e.g., ReportConfigNR), the terminal (6-05) can select cells up to maxReportCells in the order of good signal strength among the cells included in the cellsTriggeredList through the procedure of [Table 7]. The terminal (6-05) can include the measurement results for the selected cells in measResultsNeighCells included in the measurement report.

[0116] For example, if the terminal (6-05) has Event-based reporting set as the report type in the configuration information that started or triggered the measurement reporting procedure, and the enteringLeavingReport indicator is set for the report configuration, the measurement report may include information indicating the 'cell that first satisfied the entering condition' and the 'cell that satisfied the leaving condition' for the Event, as shown in [Table 9] below. For example, the measurement report may include an indicator for the cell that first satisfied the entering condition and / or an indicator for the cell that satisfied the leaving condition.

[0117]

[0118] According to the procedure in [Table 9], when the entering condition of the Event that triggered the measurement report for each cell included in measResultNeighCells is satisfied for the first time after the report setting, the terminal (6-05) can set the firstEntering indicator value to 'true' for the cell that satisfied the entering condition. For example, when the base station (6-10) receives a measurement report, if the firstEntering indicator value is set to 'true' in the measurement information (e.g., MeasResultNR) for each cell included in measResultNeighCells, the base station (6-10) can identify that the cell indicated by the indicator satisfied the entering condition of the Event for the first time. Therefore, by the operation of the terminal (6-05) described above, the base station (6-10) can make an accurate judgment on Issue 1 in the embodiment situation of FIG. 5 and make a correct handover decision.

[0119] According to the procedure of [Table 9], the terminal (6-05) can set the cellsMetReportOnLeaveList in the measurement report to include the cells in the cellsMetLeavingCond if the cellsMetLeavingCond stored in the VarMeasReportList is not empty according to the procedure of [Table 7]. When the base station (6-10) receives the measurement report, it can identify that the cells included in the cellsMetReportOnLeaveList satisfy the leaving condition of the Event that triggered the measurement report. Therefore, the base station (6-10) can make an accurate judgment on Issue 2 in the embodiment situation of FIG. 5 and make a correct handover decision by the operation of the terminal (6-05) described above. For example, the base station (6-10) can accurately identify whether Cell B satisfied the leaving condition at time T3 (1e-35) in the embodiment situation described in FIG. 6 and was not reported because its signal strength was worse than that of Cells A and C. If Cell B is not reported because it satisfies the leaving condition for Event A4, the base station (6-10) may determine that the signal strength for Cell B is no longer good and may cancel the condition-based handover setup for Cell B.

[0120] As described above, when the base station (6-10) sets the enteringLeavingReport indicator in the reporting settings, the terminal (6-05) transmits a measurement report (MR) and can explicitly report the ‘cell that first satisfies the entering condition’ and the ‘cell that satisfies the leaving condition’ for the event that triggered the transmitted MR.

[0121] According to one embodiment of the present disclosure, the terminal (6-05) may perform the procedure of [Table 8] to report the 'cell that satisfies the leaving condition' to the base station (6-10). In the procedure of [Table 8], if there are cells that satisfy the leaving condition for an event, the terminal (6-05) may always store or include the cells that satisfy the leaving condition in cellsMetLeavingCond. This may be so that the terminal (6-05) can explicitly report the 'cell that satisfies the leaving condition' to the base station (6-10) later through a measurement report transmission. However, referring to the actual procedures of [Table 8] and [Table 9], the terminal (6-05) can report the 'cell that satisfies the leaving condition' to the base station (6-10) through a measurement report transmission only when the base station (6-10) sets the reportOnLeave indicator and the enteringLeavingReport indicator to 'true' in the report configuration in step 6-20. Accordingly, even if the terminal (6-05) does not report the actual 'cells satisfying the leaving condition' to the base station (6-10) (in other words, even if the reportOnLeave indicator and the enteringLeavingReport indicator are not set), it may perform an inefficient operation of storing and deleting cells that have unnecessarily satisfied the leaving condition in cellsMetLeavingCond.

[0122] According to one embodiment of the present disclosure, in order to solve the issue, in the procedure of [Table 8], the terminal (6-05) may perform an operation of storing cells that satisfy the leaving condition in cellsMetLeavingCond only when at least one combination of the following conditions is satisfied.

[0123] - Condition 1: The reportOnLeave directive must be set to 'true' for the reporting settings corresponding to the event. In other words, the terminal must be configured to trigger the measurement reporting procedure when a cell that satisfies the leaving condition for the event occurs.

[0124] - Condition 2: The enteringLeavingReport directive must be set for the reporting settings corresponding to the event. In other words, when the terminal (6-05) transmits a measurement report triggered by a specific event, the terminal (6-05) must be configured to explicitly report the "cell that first satisfied the entering condition" and the "cell that satisfied the leaving condition" for that event.

[0125] The solution to the issue described above can be described in the standard as one of the examples in [Table 10] below.

[0126]

[0127] According to one embodiment of the present disclosure, the terminal (6-05) may perform at least some of the procedures of [Table 8] to report 'cells satisfying the leaving condition' to the base station. In the procedure of [Table 8], the terminal (6-05) may store cells satisfying the leaving condition in cellsMetLeavingCond if there are cells among the cells included in the cellsTriggeredList through the procedure of [Table 7] that satisfy the leaving condition for the corresponding event. However, the maximum number of cells that can be included in the cellsTriggeredList (maxNrofCellMeas) is defined as '32' according to the standard, and the maximum number of cells that can be included in cellsMetLeavingCond (maxCellReport) is defined as '8'. Therefore, an issue may arise in which the number of cells among the cells included in the cellsTriggeredList that satisfy the leaving condition for the event is greater than the maximum number of cells that can be included in cellsMetLeavingCond.

[0128] According to one embodiment of the present disclosure, to address the above-described issues, at least one of the following options may be used.

[0129] - Option 1: The maximum number of cells that can be included in cellsMetLeavingCond can be changed to '32', which is the same value as the maximum number of cells that can be included in cellsTriggeredList (maxNrofCellMeas). In this case, even if there are up to 32 cells that satisfy the leaving condition among the cells included in cellsTriggeredList, the terminal (6-05) can include all cells that satisfy the leaving condition in cellsMetLeavingCond. For reference, cellsMetLeavingCond is a list stored in the internal memory of the terminal (6-05), and when transmitting an actual measurement report, cellsMetReportOnLeaveList in the message can be used to report 'cells that satisfy the leaving condition'. Therefore, the maximum number of cells that can be included in cellsMetReportOnLeaveList can also be changed to '32'. The above-described method can be reflected in the specification as shown in [Table 11] below.

[0130]

[0131] - Option 2: The terminal (6-05) can report to the base station (6-10) only the cells that have been previously reported to the network (e.g., base station) among the cells that satisfy the leaving condition. The main motivation for the action of the terminal (6-05) reporting the cells that actually satisfy the leaving condition to the base station (6-10) is to cancel the condition-based handover configuration that the base station (6-10) has previously set for the cells. Therefore, cells that have not been previously reported to the base station (6-10) may not necessarily need to be reported to the base station (6-10) even if they satisfy the leaving condition. For reference, the terminal (6-05) can report the measurement results for up to '8' neighboring cells through measResultNeighCells in the measurement report, depending on the configuration of the base station (6-05). Therefore, by adding a condition to report only previously reported cells among the cells that satisfy the leaving condition, the number of cells to be included in cellsMetLeavingCond can be adjusted to within the currently defined maximum number of '8'. As another example, the terminal (6-05) can include cells that have been previously reported to the network (e.g., base station) among the cells that satisfy the leaving condition in cellsMetLeavingCond with a higher priority, and then include the remaining cells thereafter if possible. The above-described method can be reflected in the specification as shown in [Table 12] below.

[0132]

[0133] - Option 3: If the number of cells that satisfy the leaving condition among the cells included in cellsTriggeredList is greater than the maximum number of cells that can be included in cellsMetLeavingCond, the decision on which cells can be included in cellsMetLeavingCond can be left to the implementation of the terminal (6-05). In this case, the decision on which cells to include can be included as a note in the specification, as in the examples in [Table 13] below, by leaving it to the implementation of the terminal (6-05).

[0134]

[0135] According to one embodiment of the present disclosure, the terminal (6-05) may perform the procedure of [Table 9] to report to the base station (6-10) the 'cell that satisfies the entering condition for the first time'. At this time, the terminal (6-05) may set the firstEntering indicator value in the measurement result (e.g., MeasResultNR) for the cell to 'true' when the entering condition is satisfied for the first time after the measurement report setting for each cell included in measResultNeighCells. Accordingly, the terminal (6-05) may report to the base station (6-10) whether the entering condition is satisfied for the first time only for up to 8 cells included in measResultNeighCells. However, according to the procedure of [Table 7], the terminal (6-05) may include up to '32' cells that satisfy the entering condition for a specific event in the cellsTriggeredList. This may mean that the terminal may store up to '32' cells that satisfy the entering condition for the first time. Therefore, in order to report all of the 'cells that first satisfy the entering condition' up to a maximum of 32 that the terminal (6-05) is actually storing (or can report), at least one of the following options may be used.

[0136] - Option 1: When a Measurement report is triggered, a new information element (IE) (e.g., cellsMetEnteringCond) may be introduced in the measurement results (e.g., MeasResults) to report all cells currently included in the cellsTriggeredList to the base station. At this time, the new IEcellsMetEnteringCond may include at least 1 and at most 32 physical cell IDs (e.g., PhysCellId) of the cells included in the cellsTriggeredList.

[0137] - Option 2: When a measurement report is triggered, a new IE (e.g., cellsMetFirstEnteringCond) can be introduced in the measurement result (e.g., MeasResults) to report cells that satisfy the entering condition for the first time but are not included in measResultNeighCells. In this case, the UE can indicate whether the entering condition is satisfied for the first time through the firstEntering indicator for at least 1 and at most 8 cells included in measResultNeighCells. Accordingly, the new IEcellsMetFirstEnteringCond can include the physical cell IDs (e.g., PhysCellId) of the remaining at least 1 and at most 31 'cells that satisfied the entering condition for the first time'.

[0138] According to one embodiment of the present disclosure, when a measurement reporting procedure is started or triggered by a report configuration linked to a specific measId, the terminal (6-05) may repeatedly transmit a measurement report (hereinafter referred to as MR) a numberOfReportsSent times with a reportInterval included in the measurement report configuration as a cycle. This periodic MR transmission operation of the terminal (6-05) may also be applied when the report type (e.g., reportType) of the report configuration includes an Event-based reporting configuration rather than a periodic reporting configuration. The main motivation for the periodic MR transmission operation described above in the Event-based reporting may be to determine whether the optimal neighboring cell (e.g., best cell) for the terminal changes over time after the occurrence of the corresponding Event. Therefore, if the optimal neighboring cell of the terminal (6-05) does not change, the repeated MR transmission operation may be unnecessary and inefficient. To avoid such inefficient periodic MR transmission operation, the base station (6-10) can include (or set) a reportOnBestCellChange indicator in the report configuration in step 6-20 so that the terminal triggers MR transmission only when the actual best cell has changed. The indicator (e.g., reportOnBestCellChange indicator) can be set to either the value of 'n1' or 'n2'. When the indicator is set to 'n1', the terminal can transmit MR only when the top one among the neighboring cells (e.g., the cell with the first best measured signal strength among the cells included in measResultNeighCells) has changed. In addition, when the indicator is set to 'n2', the terminal can transmit MR only when the top two among the neighboring cells (e.g., the cells with the first and second best measured signal strength among the cells included in measResultNeighCells) have changed.The above-described actions can be described in the standard as shown in [Table 14] below.

[0139]

[0140] According to the procedure in [Table 14], the terminal (6-05) can compare the first and second cells included in reportedBestNeighbourCell with the cell with the first best measured signal strength (e.g., the cell with the highest signal strength) and the second best cell (e.g., the cell with the second highest signal strength) among the cells in cellsTriggeredList to determine whether the previously reported best cell(s) and the best cell(s) at the current point in time have changed. At this time, the first and second cells included in reportedBestNeighbourCell may refer to the cells with the first and second best signal strengths at the time of the last MR transmission. For this comparison operation, the terminal (6-05) can store (or set) the cells with the first and second best cell signal strengths among the cells included in measResultNeighCells as the first and second cells included in reportedBestNeighbourCell each time it transmits an MR. The above-described actions can be described in the standard as shown in [Table 15] below.

[0141]

[0142] According to the procedure in [Table 15], when reportOnBestCellChange is set to 'n1', the terminal (6-05) can set the reportedBestNeighbourCell as the first cell in measResultNeighCells. Also, when reportOnBestCellChange is set to 'n2', the terminal (6-05) can set the first cell and the second cell in reportedBestNeighbourCell as the first cell and the second cell in measResultNeighCells, respectively. However, in the procedure described above, if there is no cell or only one cell included in measResultNeighCells, the terminal may fail to set the first cell and the second cell in reportedBestNeighbourCell according to the procedure described above.

[0143] According to one embodiment of the present disclosure, in order to resolve the issue of failing to set up a cell, the terminal (6-05) may store (or set up) the first cell and the second cell in the reportedBestNeighbourCell only when the first cell and the second cell in the measResultNeighCells exist, respectively. The above-mentioned solution may be described in the standard as in the examples of [Table 16] below.

[0144]

[0145] In step 6-30, the terminal can transmit the measurement report set (or, set) as described in step 6-25 to the base station. MeasurementReport (cellsMetReportOnLeaveList in MeasResults, firstEntering in MeasResultNR)

[0146] In step 6-15, the terminal (6-05) can report to the base station (6-10) via a UE capability information message whether it understands (or identifies) the reportOnBestCellChange and enteringLeavingReport directives in the reporting configuration and supports the related operations described in step 6-25. For example, the base station (6-10) can transmit a UE capability enquiry message to the terminal to request transmission of a UE capability information message from the terminal, and the terminal (6-05) receiving the message can transmit a UE capability information message. For example, the terminal (6-05) can indicate to the base station (6-10) that it is a terminal that understands / supports the reportOnBestCellChange and enteringLeavingReport directives in the reporting configuration by including the related directives (e.g., bestCellChangeReport and enterAndLeaveCellReport) in the UE capability information message and transmitting it. Conversely, if the terminal (6-05) does not include or omits the directives (e.g., bestCellChangeReport and enterAndLeaveCellReport), it may mean that the terminal does not understand / support the reportOnBestCellChange and enteringLeavingReport directives in the report configuration.

[0147] For example, since the reportOnBestCellChange and / or enteringLeavingReport directives in the report configuration (e.g., reportOnBestCellChange-r18 and enteringLeavingReport-r18 directives in ReportConfigNR) were introduced in the 3GPP Release 18 standard, even if a previous Release terminal (e.g., a Release 17 terminal) receives the corresponding directives in the report configuration from the base station, it may not understand them and may not be able to perform the related actions. In this case, since the terminal (6-05) may operate differently from the intention of the base station (6-10), the base station (6-10) may first receive whether the terminal (6-05) understands / supports the reportOnBestCellChange and enteringLeavingReport indicators in the report configuration through a UE capability message (e.g., step 6-15), and may set the reportOnBestCellChange and enteringLeavingReport indicators in the report configuration to the terminal (6-05) accordingly (e.g., step 6-20). For example, if the terminal (6-05) does not support the reportOnBestCellChange and enteringLeavingReport indicators in the report configuration, the base station (6-10) may not set the reportOnBestCellChange and enteringLeavingReport indicators in the report configuration to the terminal (6-05). Conversely, if the terminal (6-05) supports the reportOnBestCellChange and enteringLeavingReport directives in the report settings, the base station (6-10) can set the reportOnBestCellChange and enteringLeavingReport directives in the report settings to the terminal (6-05).

[0148] FIG. 7 is a diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0149] Referring to FIG. 7, the terminal may include an RF (Radio Frequency) processing unit (7-10), a baseband processing unit (7-20), a storage unit (7-30), and a control unit (7-40).

[0150] The RF processing unit (7-10) may perform functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. For example, the RF processing unit (7-10) may up-convert a baseband signal provided from the baseband processing unit (7-20) into an RF band signal and transmit the same through an antenna, and may down-convert an RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (7-10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In Fig. 7, only one antenna is illustrated, but the terminal may be equipped with multiple antennas. In addition, the RF processing unit (7-10) may include multiple RF chains. In addition, the RF processing unit (7-10) may perform beamforming. For the above beamforming, the RF processing unit (7-10) can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. In addition, the RF processing unit can perform MIMO (multi-input multi-output) and can receive multiple layers when performing MIMO operation.

[0151] The baseband processing unit (7-20) above can perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (7-20) can generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (7-20) can restore a reception bit stream by demodulating and decoding a baseband signal provided from the RF processing unit (7-10). For example, in the case of following the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit (7-20) can generate complex symbols by encoding and modulating a transmission bit stream, and after mapping the complex symbols to subcarriers, can configure OFDM symbols through an inverse fast Fourier transform (IFFT) operation and a cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processing unit (7-20) can divide the baseband signal provided from the RF processing unit (7-10) into OFDM symbol units, restore signals mapped to subcarriers through FFT (fast Fourier transform) operation, and then restore the received bit string through demodulation and decoding.

[0152] The baseband processing unit (7-20) and the RF processing unit (7-10) can transmit and receive signals as described above. Accordingly, the baseband processing unit (7-20) and the RF processing unit (7-10) may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit (7-20) and the RF processing unit (7-10) may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit (7-20) and the RF processing unit (7-10) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include a wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), etc. Additionally, the different frequency bands may include a super high frequency (SHF) (e.g., 2.NRHz, NRhz) band and a millimeter wave (mm wave) (e.g., 60GHz) band.

[0153] The storage unit (7-30) can store data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the storage unit (7-30) can store information related to a second access node that performs wireless communication using wireless access technology. In addition, the storage unit (7-30) can provide the stored data at the request of the control unit (7-40).

[0154] The above control unit (7-40) can control the overall operations of the terminal. For example, the control unit (7-40) can transmit and receive signals through the baseband processing unit (7-20) and the RF processing unit (7-10). In addition, the control unit (7-40) can record and read data in the storage unit (7-30). For this purpose, the control unit (7-40) can include at least one processor. For example, the control unit (7-40) can include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs, and can include a multi-connection processing unit (7-42) as illustrated in the drawing.

[0155] FIG. 8 is a diagram illustrating the structure of a base station according to one embodiment of the present disclosure.

[0156] Referring to FIG. 8, according to an example of the present disclosure, a base station may be configured to include an RF processing unit (8-10), a baseband processing unit (8-20), a backhaul communication unit (8-30), a storage unit (8-40), and a control unit (8-50).

[0157] The RF processing unit (8-10) can perform functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (8-10) can up-convert a baseband signal provided from the baseband processing unit (8-20) into an RF band signal and then transmit it through an antenna, and can down-convert an RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (8-10) can include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. In the drawing, only one antenna is shown, but the base station can be equipped with multiple antennas. In addition, the RF processing unit (8-10) can include multiple RF chains. In addition, the RF processing unit (8-10) can perform beamforming. For the above beamforming, the RF processing unit (8-10) can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. The RF processing unit can perform a downlink MIMO operation by transmitting one or more layers.

[0158] The baseband processing unit (8-20) above can perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the wireless access technology. For example, when transmitting data, the baseband processing unit (8-20) can generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (8-20) can restore a reception bit stream by demodulating and decoding the baseband signal provided from the RF processing unit (8-10). For example, in the case of OFDM, when transmitting data, the baseband processing unit (8-20) can generate complex symbols by encoding and modulating a transmission bit stream, and after mapping the complex symbols to subcarriers, configure OFDM symbols through IFFT operation and CP insertion. In addition, when receiving data, the baseband processing unit (8-20) can divide the baseband signal provided from the RF processing unit (8-10) into OFDM symbol units, restore the signals mapped to subcarriers through FFT operation, and then restore the received bit string through demodulation and decoding. The baseband processing unit (8-20) and the RF processing unit (8-10) can transmit and receive signals as described above. Accordingly, the baseband processing unit (8-20) and the RF processing unit (8-10) may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0159] The above backhaul communication unit (8-30) can provide an interface for performing communication with other nodes within the network. That is, the backhaul communication unit (8-30) can convert a bit string transmitted from the main base station to another node, such as an auxiliary base station or a core network, into a physical signal, and can convert a physical signal received from the other node into a bit string.

[0160] The storage unit (8-40) can store data such as basic programs, application programs, and setting information for the operation of the base station. In particular, the storage unit (8-40) can store information on bearers assigned to connected terminals, measurement results reported from connected terminals, and the like. In addition, the storage unit (8-40) can store information that serves as a judgment criterion for whether to provide or terminate multiple connections to a terminal. In addition, the storage unit (8-40) can provide stored data at the request of the control unit (8-50).

[0161] The control unit (8-50) can control the overall operations of the base station. For example, the control unit (8-50) can transmit and receive signals through the baseband processing unit (8-20) and the RF processing unit (8-10) or through the backhaul communication unit (8-30). In addition, the control unit (8-50) can record and read data in the storage unit (8-40). For this purpose, the control unit (8-50) can include at least one processor and, as illustrated in the drawing, a multi-connection processing unit (8-52).

[0162] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples to easily explain the technical contents of the present disclosure and to help understand the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those skilled in the art that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, the above-described embodiments can be combined and operated as needed. For example, parts of one embodiment of the present disclosure and another embodiment can be combined to operate a base station and a terminal. Furthermore, the embodiments of the present disclosure can be applied to other communication systems, and other modifications based on the technical idea of ​​the embodiments can also be implemented. For example, the embodiments can be applied to LTE systems, 5G, NR systems, or 6G systems. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be determined not only by the scope of the following claims but also by equivalents of the claims.

[0163] In the specific embodiments of the present disclosure described above, components included in the present disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0164] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples to easily explain the technical contents of the present disclosure and to help understand the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those skilled in the art that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, the respective embodiments may be combined and operated with each other as needed. For example, parts of one embodiment of the present disclosure and another embodiment may be combined with each other to operate a base station and a terminal. In addition, the embodiments of the present disclosure are applicable to other communication systems, and other modifications based on the technical idea of ​​the embodiments may also be implemented.

Claims

1. In a method performed by UE (user equipment), A step of receiving, from a base station, configuration information for a first measurement report, the configuration information including information about an event triggering the first measurement report; If a leaving condition applied to the event is satisfied for at least one cell and entering leaving report information is included in the setting information, storing the at least one cell in a list of cells satisfying the leaving condition; and A method comprising the step of transmitting the first measurement report including the list to the base station.

2. In claim 1, A method further comprising the step of removing at least one cell from the cells triggered list when the leaving condition is satisfied for at least one cell.

3. In claim 1, The above first measurement report is transmitted to the base station when the report on leave information included in the above setting information is set to indicate true, A method in which all cells included in the above list are removed from the above list.

4. In claim 1, A method wherein the above configuration information includes first information indicating whether the UE transmits a second measurement report when one best cell changes or when two best cells change.

5. In claim 4, A method further comprising, if available, setting a first cell included in the list of measurement results as a first best cell reported to the base station and setting a second cell included in the list of measurement results as a second best cell reported to the base station, when the first information indicates that the UE transmits the second measurement report when the two best cells change.

6. In claim 5, A method in which the first cell in order according to the sorting quantity among the cells triggered list is the same as the first best cell.

7. In claim 4, A method wherein the above two best cells include a cell with the highest RSRP (reference signal received power) among the cells triggered list and a cell with the second highest RSRP among the cells triggered list.

8. In UE (user equipment), At least one transceiver; At least one processor communicatively coupled to said at least one transceiver; and At least one memory communicatively coupled to said at least one processor and storing instructions, The above instructions are executed individually or in any combination by the at least one processor so that the UE: Receive configuration information for a first measurement report from a base station, wherein the configuration information includes information about an event that triggers the first measurement report; If the leaving condition applied to the above event is fulfilled for at least one cell and entering leaving report information is included in the setting information, store the at least one cell in a list of cells satisfying the leaving condition, A UE that transmits the first measurement report including the list to the base station.

9. In claim 8, The above commands cause the UE to: A UE that removes at least one cell from the cells triggered list when the leaving condition is satisfied for at least one cell.

10. In claim 8, The above first measurement report is transmitted to the base station when the report on leave information included in the above setting information is set to indicate true, The UE, wherein all cells included in the above list are removed from the above list.

11. In claim 8, The above configuration information includes first information indicating whether the UE transmits a second measurement report when one best cell changes or when two best cells change.

12. In claim 11, The above commands cause the UE to: A UE, if the first information indicates that the UE transmits the second measurement report when the two best cells change, sets the first cell included in the list of measurement results as the first best cell reported to the base station, and sets the second cell included in the list of measurement results as the second best cell reported to the base station, if available.

13. In claim 12, Among the cells triggered list, the first cell in order (according to) is the same as the first best cell, UE.

14. In claim 11, The above two best cells are a UE including a cell with the highest RSRP (reference signal received power) among the cells triggered list and a cell with the second highest RSRP among the cells triggered list.

15. One or more non-transitory computer-readable storage media storing computer-executable instructions, wherein when the computer-executable instructions are individually or collectively executed by at least one processor of a user equipment (UE), the UE: Receive configuration information for a first measurement report from a base station, wherein the configuration information includes information about an event that triggers the first measurement report; If the leaving condition applied to the above event is fulfilled for at least one cell and entering leaving report information is included in the setting information, store the at least one cell in a list of cells satisfying the leaving condition, A non-transitory recording medium that causes the base station to transmit the first measurement report including the list.

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