Method for supporting mobility and apparatus therefor

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. An operation method of a user equipment (UE) in a wireless communication system according to an embodiment of the present disclosure comprises the steps of: receiving, from a serving cell, indication information indicating transmission of a plurality of physical random access channels (PRACHs) through a physical downlink control channel (PDCCH); when resources overlapping at the same time are allocated to two or more PRACHs among the plurality of indicated PRACHs, identifying a priority among the PRACHs to which the overlapping resources are allocated; and performing transmission for a PRACH having the highest priority.

Description

Method and device for supporting mobility

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and device for supporting terminal mobility by considering an asymmetric beam or transmission configuration indication (TCI).

[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] A method for operating a UE (user equipment) in a wireless communication system according to one embodiment of the present disclosure includes the steps of: receiving, from a serving cell, instruction information indicating transmission of a plurality of physical random access channels (PRACHs) through a physical downlink control channel (PDCCH); identifying priorities between PRACHs to which overlapping resources are allocated when two or more of the indicated plurality of PRACHs are allocated resources at the same time; and performing transmission for a PRACH having the highest priority.

[0009] According to one embodiment of the present disclosure, handover can be supported by ensuring communication quality in a situation where asymmetric communication is performed in DL and UL.

[0010] FIG. 1 is a diagram illustrating an example in which an asymmetric beam / TCI state is used in downlink / uplink according to one embodiment of the present disclosure.

[0011] FIG. 2 is a diagram showing an example of a communication situation between a terminal and a base station including a UL only node according to one embodiment of the present disclosure.

[0012] FIG. 3 is a diagram illustrating an example in which an asymmetric DL / UL beam / TCI state is applied according to one embodiment of the present disclosure.

[0013] FIG. 4 is a diagram illustrating an example of a case where a delay occurs in a RACH process for handover when performing a handover decision based on downlink quality or downlink measurement according to one embodiment of the present disclosure.

[0014] Figure 5 is a diagram showing an example of communication performance degradation occurring after a handover without considering the DL / UL quality difference.

[0015] FIG. 6 is a diagram illustrating an example of how downlink quality reporting is performed according to one embodiment of the present disclosure.

[0016] FIG. 7 is a diagram illustrating another example of how downlink quality reporting is performed according to one embodiment of the present disclosure.

[0017] FIG. 8 is a diagram illustrating an example of uplink quality information reporting according to one embodiment of the present disclosure.

[0018] FIG. 9 is a diagram illustrating another example of uplink quality information reporting according to one embodiment of the present disclosure.

[0019] FIG. 10 is a diagram illustrating another example of uplink quality information reporting according to one embodiment of the present disclosure.

[0020] FIG. 11 is a diagram illustrating another example of uplink quality information reporting according to one embodiment of the present disclosure.

[0021] FIG. 12 is a diagram showing an example of how downlink quality reporting and uplink quality reporting are performed according to one embodiment of the present disclosure.

[0022] FIG. 13 is a diagram showing an example in which, when reporting on cells / TCIs ​​that have been set for DL ​​quality measurement and reporting according to one embodiment of the present disclosure, reporting is performed only for cells / TCIs ​​that satisfy specific conditions.

[0023] FIG. 14 is a diagram showing an example of report information according to report condition settings according to one embodiment of the present disclosure.

[0024] FIG. 15 is a block diagram illustrating the functional structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0025] FIG. 16 is a block diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0026] A method for operating a UE (user equipment) in a wireless communication system according to one embodiment of the present disclosure includes the steps of: receiving, from a serving cell, instruction information indicating transmission of a plurality of physical random access channels (PRACHs) through a physical downlink control channel (PDCCH); identifying priorities between PRACHs to which overlapping resources are allocated when two or more of the indicated plurality of PRACHs are allocated resources at the same time; and performing transmission for a PRACH having the highest priority.

[0027] In one embodiment, the instruction information indicating the transmission of the plurality of PRACHs may include an index indicating a synchronization signal block (SSB) corresponding to each of the plurality of PRACHs.

[0028] In one embodiment, the priority may be identified based on at least one of a transmission request power and a maximum allowable power of each of the plurality of PRACHs.

[0029] In one embodiment, the indication information indicating the plurality of PRACH transmissions includes information indicating a common PRACH resource for a plurality of cells, and the common PRACH resource may be associated with at least one of a plurality of SSB resources, a plurality of cell IDs (identifications), and an uplink RSRP (reference signal received power) measurement result.

[0030] In one embodiment, the method may further include: measuring path loss through radio resources allocated to SSB for each of the plurality of cells to which the common PRACH resources are allocated; and identifying PRACH transmission power based on the largest path loss among the measured path losses.

[0031] In one embodiment, transmission of a random access response (RAR) message may be omitted.

[0032] In one embodiment, the method may further include transmitting a quality report for a downlink beam and / or a transmission configuration indicator (TCI) and an uplink quality report associated with the downlink beam and / or TCI to the serving cell.

[0033] In one embodiment, the method may further include transmitting an uplink quality report to the serving cell only if a preset reporting condition is satisfied.

[0034] According to one embodiment of the present disclosure, a user equipment (UE) comprises: at least one transceiver; at least one processor communicatively coupled to the at least one transceiver; and at least one memory communicatively coupled to the at least one processor and storing instructions, wherein the instructions are individually or in any combination executed by the at least one processor so that the UE: receives, from a serving cell, instruction information indicating transmission of a plurality of physical random access channels (PRACHs) through a physical downlink control channel (PDCCH), and, when two or more of the indicated plurality of PRACHs are allocated overlapping resources at the same time, identifies priorities between the PRACHs to which the overlapping resources are allocated, and performs transmission for the PRACH having the highest priority.

[0035] In one embodiment, the instruction information indicating the transmission of the plurality of PRACHs may include an index indicating a synchronization signal block (SSB) corresponding to each of the plurality of PRACHs.

[0036] In one embodiment, the priority may be identified based on at least one of a transmission request power and a maximum allowable power of each of the plurality of PRACHs.

[0037] In one embodiment, the indication information indicating the plurality of PRACH transmissions includes information indicating a common PRACH resource for a plurality of cells, and the common PRACH resource may be associated with at least one of a plurality of SSB resources, a plurality of cell IDs (identifications), and an uplink RSRP (reference signal received power) measurement result.

[0038] In one embodiment, the instructions may cause the UE to: measure path loss through radio resources allocated to SSB for each of the plurality of cells to which the common PRACH resource is allocated, and identify a PRACH transmission power based on a largest path loss among the measured path losses.

[0039] In one embodiment, transmission of a random access response (RAR) message may be omitted.

[0040] In one embodiment, the commands may cause the UE to transmit to the serving cell: a quality report for a downlink beam and / or a transmission configuration indicator (TCI) and an uplink quality report associated with the downlink beam and / or TCI.

[0041] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the attached drawings. It should be noted that, where possible, identical components are represented by identical reference numerals throughout the attached drawings. Furthermore, detailed descriptions of well-known functions and configurations that may obscure the gist of the present disclosure will be omitted.

[0042] In describing the embodiments of this disclosure, descriptions of technical details that are well known in the technical field to which this disclosure pertains and are not directly related to this disclosure will be omitted. This is to more clearly convey the gist of this disclosure without obscuring it by omitting unnecessary explanations.

[0043] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0044] 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. These embodiments are provided solely to ensure that the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined solely by the scope of the claims. Like reference numerals designate like elements throughout the disclosure.

[0045] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These 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 by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These 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 the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0046] 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.

[0047] Here, the term '~ part' used in this embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and the '~ part' performs certain roles. However, the '~ part' is not limited to software or hardware. The '~ part' may be configured to be on an addressable storage medium or may be configured to play one or more processors. Therefore, as an example, the '~ part' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ parts' may be combined into a smaller number of components and '~ parts' or further separated into additional components and '~ parts'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within a device or secure multimedia card. In addition, in an embodiment, the '~parts' may include one or more processors.

[0048] In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Hereinafter, embodiments of the present disclosure will be described with reference to the attached drawings.

[0049] 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 entities, terms referring to various identification information, etc. 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.

[0050] In the following description, the terms "physical channel" and "signal" may be used interchangeably with data or control signals. For example, while PDSCH (physical downlink shared channel) refers to a physical channel through which data is transmitted, PDSCH may also be used to refer to data. That is, in the present disclosure, the expression "transmitting a physical channel" may be interpreted equivalently to the expression "transmitting data or a signal through a physical channel."

[0051] Hereinafter, in the present disclosure, upper signaling refers to a signal transmission method in which a base station transmits a signal to a terminal using a downlink data channel of the physical layer, or a terminal transmits a signal to a base station using an uplink data channel of the physical layer. Upper signaling can be understood as radio resource control (RRC) signaling or a media access control (MAC) control element (CE).

[0052] Furthermore, while this disclosure describes various embodiments using terminology used in certain communication standards (e.g., 3rd Generation Partnership Project (3GPP)), these are merely illustrative examples. The various embodiments of this disclosure can be easily modified and applied to other communication systems. Furthermore, the term "terminal" can refer to not only cell phones, smartphones, IoT devices, and sensors, but also other wireless communication devices.

[0053] Hereinafter, a base station is an entity that performs resource allocation of a terminal, and may be at least one of a gNode B, a gNB, an eNode B, an eNB, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (user equipment), an MS (mobile station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. Of course, the present invention is not limited to the above examples. In addition, although various embodiments of the present invention are described below using a system based on LTE, LTE-A, or NR as an example, various embodiments of the present invention may be applied to other communication systems having a similar technical background or channel type. In addition, various embodiments of the present invention may be applied to other communication systems through some modifications without significantly departing from the scope thereof at the discretion of a person having skilled technical knowledge.

[0054] To handle the explosive growth in mobile data traffic, the initial standards for the 5G (5th generation) system, or NR (new radio access technology), the next-generation communication system following LTE (long term evolution or E-UTRA (evolved universal terrestrial radio access)) and LTE-A (LTE-advanced or E-UTRA Evolution), have been completed. While existing mobile communication systems have focused on conventional voice / data communications, the 5G system aims to satisfy various services and requirements, such as enhanced Mobile BroadBand (eMBB) services to improve existing voice / data communications, ultra-reliable and low latency communication (URLLC) services, and massive machine type communication (MTC) services that support large-scale machine-type communication.

[0055] While the transmission bandwidth of existing LTE and LTE-A systems per single carrier is limited to a maximum of 20MHz, the 5G system aims to utilize a much wider ultra-wide bandwidth to provide ultra-high-speed data services of up to several Gbps. Accordingly, the 5G system is considering ultra-high frequency bands ranging from several GHz up to 100 GHz as candidate frequencies, where securing ultra-wide bandwidth frequencies is relatively easy. Additionally, wide bandwidth frequencies for the 5G system can be secured through frequency reallocation or allocation within frequency bands ranging from several hundred MHz to several GHz used in existing mobile communication systems.

[0056] Ultra-high frequency radio waves, sometimes called millimeter waves (mmWave), have wavelengths on the order of millimeters. However, in ultra-high frequency bands, path loss increases proportionally to the frequency band, reducing the coverage of mobile communication systems.

[0057] To overcome the drawback of reduced coverage in ultra-high frequency bands, beamforming technology is applied, which uses multiple antennas to focus radio wave energy toward a predetermined target point and thereby increase the transmission range. In other words, a signal using beamforming technology has a relatively narrow beam width, and the radiation energy is concentrated within this narrowed beam width, increasing the transmission range. Beamforming technology can be applied to both the transmitter and receiver. In addition to increasing coverage, beamforming technology also reduces interference in areas outside the beamforming direction. For beamforming technology to function properly, accurate measurement and feedback methods for the transmission and reception beams are required. Beamforming technology can be applied to control channels or data channels that correspond one-to-one between a given terminal and a base station. Furthermore, beamforming can also be applied to common signals transmitted by a base station to multiple terminals within a system, such as synchronization signals, physical broadcast channels (PBCHs), and control and data channels for transmitting system information, to increase coverage. When applying beamforming technology to a common signal, beam sweeping technology, which transmits a signal by changing the beam direction, is additionally applied so that the common signal can reach terminals located at any location within the cell.

[0058] Another requirement for 5G systems is ultra-low latency services, with transmission delays of approximately 1ms between transmitters and receivers. One way to reduce transmission delay is to design a frame structure based on a short transmission time interval (TTI) compared to LTE and LTE-A. A TTI is the basic unit of time for scheduling, and the TTI of existing LTE and LTE-A systems is 1ms, which corresponds to the length of one subframe. For example, to meet the ultra-low latency requirements of 5G systems, possible short TTIs include 0.5ms, 0.25ms, and 0.125ms, which are shorter than those of existing LTE and LTE-A systems.

[0059] Inter-cell handover and terminal mobility support are core technologies in mobile communications. The most important factor in determining whether a handover should occur and the target cell for the handover is the link quality that can be secured in the link between each cell and the terminal. Mobility management can be performed based on link quality typically measured via a downlink reference signal (DL RS). This disclosure describes a mobility management technique that can be used in situations where conventional downlink quality alone is not adequate for selecting a target cell and determining whether to perform a handover.

[0060] Communication of a mobile communication terminal begins with the terminal searching for an appropriate cell and attempting a RACH (random access channel) to the cell. If the RACH attempt is successful, a link is established between the serving cell and the terminal, and communication quality can be guaranteed through link management and link adaptation thereafter. At this time, if the quality of the link between the serving cell and the terminal deteriorates due to reasons such as a change in the communication environment or movement of the terminal, the terminal begins searching for a new cell, and if a cell that can guarantee better link quality than the current serving cell (or source cell) is found as a result of the search, the cell is set as the target cell, and a handover can be performed between the source cell and the target cell.

[0061] In cellular communication, handover is an essential process, and handover failure can cause serious degradation in the communication quality of the terminal. Therefore, sufficient review of the target cell before a handover decision is made is an essential operation to ensure the communication quality of the terminal. Existing mobility techniques are designed to measure the downlink quality (DL quality) of the source cell and the target cell for a sufficiently long period of time, report the measurement results, and then make a handover decision based on the results. Such existing mobility techniques can be referred to as L3 (Layer 3) signal-based handover. In CDMA (Code-Division Multiple Access) and LTE (long-term evolution) systems, the L3 signal-based handover showed excellent performance. However, as the operation band increases and widens, an environment has been created in which the link quality changes rapidly compared to the existing link quality. Especially in downtown environments, where shadowing is frequent and fading is significant, link quality changes significantly compared to the existing link quality. Consequently, the existing L3 signaling-based handover, which determines handover decisions based on continuous downlink quality measurements over a period of time, has reached its limits.

[0062] To overcome the limitations of L3 signaling-based handover, techniques such as Dual Active Protocol Stacks (DAPS) have been developed in 5G, which maintain a link with the source cell until the link establishment with the target cell is complete. In addition to theoretically eliminating interruption time, this technique also has the advantage of allowing the UE to continue communication through the existing link with the source cell if the handover to the target cell fails. Conditional handover (CHO) has been designed in 5G to reduce UE complexity compared to DAPS. For a UE configured to operate based on the CHO technique, when the UE receives a handover command transmitted by the base station, instead of immediately performing the handover procedure, the UE performs additional actions to determine whether the handover decision is appropriate based on preset conditions. If the conditions are met, the UE initiates the handover procedure. By operating the terminal according to CHO, situations where handover fails due to an incorrect handover decision by the base station or where the terminal is handed over to an inappropriate cell can be avoided. In addition, as a method to support on-time decision, the LTM (Low layer Triggered Mobility) technique was designed in 5G, in which the handover decision is performed based on DL L1 (layer 1) measurements. A terminal configured to perform LTM continuously performs DL L1 measurements on multiple candidate cells and reports the results of the measurements to the serving cell. The base station selects a target cell based on the report and instructs the terminal to perform a handover to the target cell.

[0063] The techniques described above (DAPS, CHO, LTM) all share the commonality that handover procedures are initiated and performed based on DL quality measurements and reporting. Since the commercialization of data-centric mobile communication services, DL traffic has generally outpaced UL traffic. Consequently, DL quality is considered a more important factor than UL quality, making DL quality-based mobility a reasonable design choice. However, the continued increase in data rates has necessitated the use of complex link adaptation techniques, requiring terminals to perform detailed reporting of DL channels and DL quality, increasing the importance of UL quality. Furthermore, the proliferation of wireless control and dual-active services has led to an increase in UL traffic, and consequently, the importance of UL quality is gradually increasing. In addition, as the spectrum utilization method of mobile communication systems gradually shifts from FDD (Frequency Division Duplexing) to TDD (Time Division Duplexing), the increase in UL quality has also brought about the additional effect of performing UL communication with fewer radio resources and utilizing more radio resources for DL ​​communication, and thus UL quality and UL coverage have emerged as more important factors in supporting communication quality.

[0064] For example, 5G supports asymmetric DL / UL operation, where different beams or different transmission configuration indication (TCI) states are applied to DL and UL. In particular, for Rel-17, when the power that a terminal can utilize for UL is limited depending on the transmission direction due to influences such as human body impact, a directional PHR (Power Head Room) report technique was designed to allow different beams or TCI states to be applied to DL / UL by reflecting the limitation of the power that the terminal can utilize for UL according to the transmission direction. While existing beam or TCI state selection was performed based on link quality or RSRP, the above technique has the characteristic of predicting the actual UL signal quality that can be secured in UL by considering the transmission power available to the terminal together and utilizing this for link management / adaptation.

[0065] FIG. 1 is a diagram illustrating an example in which an asymmetric beam / TCI state is used in downlink / uplink according to one embodiment of the present disclosure.

[0066] As a more direct way to improve UL quality, standardization for UL-only nodes is underway in 5G Rel-19. Removing the transmitter from the existing base station structure will not only significantly reduce node costs, but also allow for more node installation through smaller node sizes.

[0067] FIG. 2 is a diagram illustrating an example of a communication situation between a terminal and a base station including a UL only node according to an embodiment of the present disclosure. Referring to FIG. 2, when a UL only node is installed, a phenomenon occurs in which the correlation between DL quality and UL quality in the link between each base station and the terminal disappears or decreases, and when applying the existing DL quality measurement-based mobility technique, a relative comparison of UL quality between cells becomes impossible when performing a handover decision. Therefore, a handover to a cell that supports high DL quality but insufficient UL quality may occur, and a handover to a cell that supports high DL quality but insufficient UL quality may result in a handover failure or RLF (Radio Link Failure). Alternatively, even if a handover failure or RLF does not occur, additional work may be required to compensate for the reduced UL quality after the handover. For example, if a terminal is connected to Cell A and moves toward Cell B, and the DL quality with Cell B is superior to the DL quality of Cell A, and a handover is performed to Cell B without considering the UL quality, a significant UL quality degradation will occur after the handover. This means that an unexpected UL quality degradation occurs because it is a situation that the network did not anticipate or consider when making a handover decision.

[0068] DL / UL asymmetric beams / TCIs ​​have been considered from a link management / adaptation perspective, but they also need to be considered from a mobility management perspective. If a handover is performed based only on DL beam / TCI information without information on appropriate UL beam / TCI, UL failure or rapid UL quality drop may occur after the handover, which may ultimately lead to handover failure or RLF (Radio Link Failure). Even if handover failure or RLF does not occur, additional work may be required to compensate for the reduced UL quality after the handover.

[0069] FIG. 3 is a diagram illustrating an example of applying an asymmetric DL / UL beam / TCI state according to an embodiment of the present disclosure. Referring to FIG. 3, this is an example of a case where a terminal performs communication through cell A and then moves toward cell B, and the DL quality supported through cell B becomes better than that of cell A. This is a situation where communication with cell B can be performed with lower path loss as the distance between the terminal and the base station constituting cell B becomes shorter than the distance between the terminal and the base station constituting cell A, and this situation is recognized by the terminal through DL quality measurement, and also recognized by the base station through a report from the terminal. In this case, the existing mobility management process determines a handover to cell B, notifies the terminal that the handover to cell B has been determined, and simultaneously transmits the handover or cell switching command to the terminal, and the terminal instructs communication through beam 5, which guarantees the best DL quality. However, when the terminal performs communication with cell B using beam 5, Tx power reduction in the direction of cell B may occur, and UL quality may deteriorate significantly after handover.

[0070] FIG. 4 is a diagram illustrating an example of a case where a delay occurs in the RACH process for handover when performing a handover decision based on downlink quality or downlink measurement according to an embodiment of the present disclosure. In the current standard, UL path loss is estimated through DL RARP measurement, and UL transmission power control is performed based on the estimated path loss. When a DL / UL asymmetry situation occurs, the UL path loss estimated through the DL measurement may be significantly different from the actual UL path loss, and in this case, the UL transmission to the target cell based on the estimated UL path loss may not be received in the target cell due to insufficient transmission power (Tx power). For example, the terminal and the base station may fail to transmit and receive PRACH. In this case, the terminal gradually increases the PRACH transmission power and retransmits the PRACH, which means that the terminal performs a handover procedure to the target cell after performing multiple PRACH transmissions, and a handover delay occurs due to multiple PRACH transmissions. PRACH transmission is generally set to have fewer transmission opportunities compared to other channels designed for transmission and reception with the serving cell, such as PxSCH / PxCCH, and therefore the handover delay due to the PRACH retransmission may be a large value that affects communication performance.

[0071] Figure 5 illustrates an example of communication performance degradation occurring after a handover that does not consider the difference in DL / UL quality. For example, Figure 5 illustrates an example of a case where different beams / TCIs ​​must be applied to DL / UL. In the above case, additional operations must be performed to find a UL beam after the handover, and until the additional operations to find a UL beam after the handover are completed, communication performance will significantly deteriorate.

[0072] The examples described above illustrate potential problems that may arise when a handover is performed without considering the UL quality that the target cell can guarantee, even when the DL quality from the serving cell degrades. Conversely, if the current serving cell fails to guarantee adequate UL quality, a method of performing a handover by selecting a cell that guarantees superior UL quality as the target cell, even if it guarantees lower DL quality, should also be considered.

[0073] The present disclosure describes the following two improvement schemes.

[0074] More specifically, as a first improvement, we propose a method for enabling the network to acquire more link quality information about a candidate cell or target cell before initiating a handover procedure. Furthermore, as a second improvement, we propose a method for acquiring additional information about UL quality during the handover procedure or preparatory work based on DL quality, and then determining whether to perform the final handover based on this information.

[0075] As a detail of the first method, the present disclosure presents a technique for reporting additional information that enables a serving cell to estimate UL quality after a handover from a terminal to a candidate cell or target cell.

[0076] If there is a concern that UL quality degradation may occur after handover to a specific cell due to UL transmission power constraints of the terminal, the terminal reports this to the source cell in advance so that the source cell can appropriately perform mobility management, such as excluding the cell from the candidate cells or target cells, or postponing handover to the specific cell until the situation improves.

[0077] More specifically, if the terminal is set to measure and report DL quality for a non-serving cell, and a transmission power constraint is expected for a specific cell among the non-serving cells, the terminal reports this to the source cell in the form of an indication, etc. For example, assume that the source cell has set Cell A, Cell B, and Cell C as candidate cells for the terminal, and further instructs the terminal to report DL quality for the above cells. In this case, when the terminal measures the DL quality for the above cells, it can confirm that a transmission power constraint occurs when the panel in charge of signal reception of Cell B or the beam / TCI related to signal reception of Cell B is utilized for UL transmission targeting Cell B. When the terminal utilizes the panel in charge of signal reception of B or the beam / TCI related to signal reception of cell B for UL transmission targeting cell B, the terminal reports information indicating that a transmission power constraint occurs to the source cell, and the source cell may change the candidate cell configuration based on the information, or may set the DL quality report for cell B to be included or excluded when measuring and reporting link quality for candidate cells based on the information. In addition, when a transmission power constraint is expected to occur for a specific cell, the source cell may take this into consideration and set the cell where the transmission power constraint occurs above a specific value or where UL quality degradation occurs above a specific value, when the terminal performs DL quality measurement and reporting for multiple candidate cells, to be excluded from the DL quality report target.

[0078] FIG. 6 is a diagram illustrating an example of performing downlink quality reporting according to an embodiment of the present disclosure. The terminal may be configured to perform DL quality measurement and reporting in the form of candidate cell configuration, multi-cell TCI configuration, etc. for multiple non-serving cells, and may perform DL quality measurement and reporting according to the configuration. When performing DL quality measurement and reporting, the terminal may perform DL quality reporting for all configured cells or non-serving cell TCIs, or may selectively perform DL quality reporting for 'n' cells or TCIs that exhibit optimal DL quality among them. Before performing the reporting, the terminal performs DL quality measurement for the configured cells or TCIs, and also determines whether the UL quality for the cells or TCIs is appropriate. The adequacy determination may be performed by comparing the available transmission power for each cell or TCI for which the DL quality measurement is configured, comparing the expected UL path loss, etc. The terminal can report the above determination result together with the DL quality.

[0079] FIG. 7 is a diagram illustrating another example of performing downlink quality reporting according to an embodiment of the present disclosure. The terminal performs reporting according to each piece of information corresponding to quality indices #0, #1, #2, etc., depending on the DL quality size to be reported. Information regarding the highest DL quality is reported corresponding to quality index #0, and at this time, information regarding the cell or TCI where the DL quality is measured is reported together with information regarding the quality index, and UL quality information regarding the corresponding cell or TCI measured or estimated above is also reported.

[0080] FIG. 8 is a diagram illustrating an example of uplink quality information reporting according to an embodiment of the present disclosure. Referring to FIG. 8, the UL quality information report may be information on the rank order of suitability between UL quality information corresponding to each cell / TCI index for which DL quality reporting is determined in response to the corresponding quality index. Alternatively, for cells / TCIs ​​with extremely low UL quality, an index indicating impropriety (Improper) may be reported instead of rank information. Alternatively, cells / TCIs ​​determined to have inadequate UL quality may be expressed in a manner of collectively assigning a largest index (#3 according to the example of FIG. 8). The above UL quality information may be determined by the terminal-allowed transmission power for each cell / TCI, or by a UL quality estimate value estimated by a calculation including the difference between the terminal-allowed transmission power and the estimated path-loss.

[0081] FIG. 9 is a diagram illustrating another example of uplink quality information reporting according to an embodiment of the present disclosure. Referring to FIG. 9, it is also possible to more directly report UL quality information comparison values ​​for each cell / TCI selected as a target of reporting. That is, according to the example of FIG. 9, a specific value indicating UL quality information may be reported. The UL quality information may be determined by the terminal's allowed transmission power for each cell / TCI, or may be determined by a UL quality estimate value estimated by a calculation including the difference between the terminal's allowed transmission power and the estimated path-loss. The reference used to calculate the UL quality information comparison value may be a UL quality information value corresponding to a quality index #0 that exhibits the maximum DL quality, or a UL quality information value corresponding to a source cell. Alternatively, the reference may be determined by a base station setting. FIG. 10 is a diagram illustrating another example of uplink quality information reporting according to an embodiment of the present disclosure. Referring to Fig. 10, the order and comparison values ​​of UL quality information values ​​can be reported together. That is, Fig. 10 may be an example of a method in which the methods according to the examples of Figs. 8 and 9 are applied together.

[0082] FIG. 11 is a diagram illustrating another example of uplink quality information reporting according to an embodiment of the present disclosure. Referring to FIG. 11, for each cell / TCI being reported, an index indicating the suitability of UL, for example, an index such as suitability = 1, unsuitability = 0, etc., may be reported. Alternatively, two or more of the UL quality report contents according to the examples described above in FIGS. 8 to 11 may be reported together.

[0083] FIG. 12 illustrates an example of how downlink quality reporting and uplink quality reporting are performed according to one embodiment of the present disclosure. Referring to FIG. 12 , the aforementioned UL quality reporting may be performed as a separate report from the DL quality reporting. In this case, the reported UL quality notification may include two or more of a quality index, a cell / TCI index, and UL quality information.

[0084] FIG. 13 is a diagram illustrating an example in which, when reporting on cells / TCIs ​​that have been set for DL ​​quality measurement and reporting according to one embodiment of the present disclosure, reporting is performed only for cells / TCIs ​​that satisfy specific conditions. When setting measurement and reporting for DL ​​quality, a source cell or a serving cell additionally transmits to a terminal information on conditions for performing measurement and reporting according to the settings. For example, after measuring DL quality by cell, TCI, or reference resource according to the settings, information related to UL quality, for example, a requirement value for transmission power permitted to the terminal when performing UL transmission according to a transmission method indicated by the set cell, TCI, or reference resource, or an expected UL quality, can be set as a condition for DL ​​quality reporting. The terminal performs DL quality reporting only for cell, TCI, or reference resource measurement values ​​that satisfy the requirement value, i.e., satisfy the reporting condition.

[0085] FIG. 14 is a diagram showing an example of reporting information according to reporting condition settings according to one embodiment of the present disclosure. Referring to FIG. 14, DL quality is measured in the order of Cell A, Cell B, source cell, and Cell C, and among these, Cell B does not satisfy the reporting condition. When the terminal performs reporting in the order of DL quality for up to three cells, or is set to do so, the terminal recognizes only the cells that satisfy the reporting condition as targets of reporting, and therefore the terminal performs DL quality reporting for Cell A, source cell, and Cell C, which showed the first, third, and fourth qualities in the order of DL quality, and Cell B is not subject to DL quality reporting even though it showed high DL quality.

[0086] When a terminal is configured to report on DL quality, the terminal may be configured with both a report configuration with a reporting condition set and a report configuration without a reporting condition set for the same measurement configuration or overlapped measurement configuration as an associated report configuration, or may be configured with two or more associated report configurations each indicating different reporting conditions. Alternatively, the terminal may be configured or instructed to perform reporting on information that is missing from the report due to failure to satisfy the reporting condition, separately from the above reporting configuration.

[0087] As another way for a UE to report UL quality for a non-serving cell, the UE may be configured or instructed to perform a PHR report for the non-serving cell or a TCI corresponding to the non-serving cell. According to the standard, when performing a PHR report, the UE may report the difference between the actual transmit power and the available power in the form of a PHR, or may calculate and report a PHR based on path loss and UL power control configuration information. The PHR value and PHR report calculated in the first way (the difference between the actual transmit power and the available power) are called actual PHR and actual PHR report, and the PHR value and PHR report calculated in the second way (based on path loss and UL power control configuration information) are called virtual PHR and virtual PHR report. In the case of a non-serving cell, it is common for a terminal to not perform UL transmission targeting the non-serving cell, and also it is common for UL power control configuration to not be performed targeting the non-serving cell. Therefore, based on the standard, the terminal cannot calculate a PHR value for the non-serving cell. As a solution to the problem that the terminal cannot calculate a PHR value for the non-serving cell, the present disclosure allows the serving cell to set UL power control parameter values, such as the P0_PUSCH value and the α value, for the non-serving cell. In addition, if the terminal fails to set the corresponding parameter values, the parameter values ​​used for PHR calculation for the serving cell are used for PHR calculation for the non-serving cell. According to the current standard, the virtual PHR calculation for the serving cell is defined according to the following mathematical formula.

[0088]

[0089] Based on this, the base station sets and instructs the terminal to simultaneously report PHR for the serving cell and non-serving cell, and when the terminal reports PHR for the serving cell and non-serving cell simultaneously, the terminal uses the PHR used for calculating the serving cell PHR. 0_PUSCH The values ​​and α are used to calculate the non-serving cell PHR, which is reported simultaneously with the serving cell PHR. f corresponding to closed-loop power control b,f,c Also, it uses the same value as the value used to calculate the serving cell PHR that is reported simultaneously with the non-serving cell PHR. On the other hand, the PL value corresponding to the path loss uses the value calculated by the terminal for the non-serving cell, and the MPR (maximum power reduction), A-MPR (additional maximum power reduction), and delta-Tc values ​​also use the values ​​defined by the terminal for the non-serving cell if they are not 0. Through this, the terminal can understand the difference between the PHR value for the serving cell and the PHR value for the non-serving cell compared to the PHR value for the serving cell.

[0090] When actual PHR reporting is performed simultaneously for both serving and non-serving cells, the terminal applies the terminal measurement and configuration results for the non-serving cell only for information about path loss and maximum allowed transmission power, and uses the same values ​​as those used for serving cell PHR calculation for other parameters. However, some parameters, for example, P 0_PUSCH If the value or α value is set for a non-serving cell, it uses the value set for the non-serving cell.

[0091] As a detail of the second method, a method is proposed in which a terminal performs additional UL transmission during a handover procedure, and a handover is determined and a target cell is selected based on the UL transmission. For example, a serving cell can trigger multiple PRACH transmissions of a terminal through a single PDCCH transmission. When the serving cell transmits a PDCCH that triggers a PRACH transmission to a terminal, it transmits to the terminal an index for an SSB that serves as a reference for the PRACH transmission, and at this time, by transmitting an index or indices indicating multiple SSBs to the terminal, the serving cell can instruct the terminal to transmit multiple PRACHs. The terminal performs simultaneous transmission of all PRACHs instructed to be transmitted, if possible, based on the simultaneous transmission capacity, the required transmission power for each PRACH transmission and the entire PRACH transmission, the available power of the terminal, and the time axis resource mapping of the PRACHs instructed to be transmitted. Otherwise, the terminal performs sequential transmission for the PRACHs instructed to be transmitted. When the terminal performs sequential transmission for multiple PRACHs instructed to be transmitted through the same PDCCH, the order of PRACH transmission can be determined as follows.

[0092] ● For each PRACH transmission of a terminal, if information about time domain resources on which each PRACH transmission can be performed is set to the terminal, the terminal performs sequential PRACH transmission based on the information. When performing sequential PRCH transmission, if there are PRACHs to which time domain resources are allocated to perform transmission at the same time, the terminal may omit / drop transmission of a PRACH with a lower priority according to priority. For example, the terminal may omit transmission of a PRACH that requires more transmission power. Alternatively, the terminal may omit transmission of a PRACH that requires transmission power closer to the maximum allowable power. For example, if simultaneous PRACH transmissions for candidate cell A and candidate cell B are triggered, the transmission required powers of each PRACH are 20 dBm and 21 dBm, and the maximum allowable powers for each PRACH are 21 dBm and 23 dBm, respectively, the UE may miss / drop the PRACH transmission for candidate cell A.

[0093] ● Alternatively, when the terminal performs each PRACH transmission, the transmission order can be defined according to the index assigned to the SSB that serves as the reference for the PRACH transmission. For example, when setting a DL measurement reference signal (measurement RS) for a non-serving cell to the terminal, if the base station sets a specific SSB of candidate cell A as measurement RS #1 and a specific SSB of candidate cell B as measurement RS #2, and if transmission of PRACHs corresponding to the two SSBs is instructed to the terminal through the same PDCCH, the terminal performs sequential PRACH transmission by preferentially performing PRACH transmission associated with the specific SSB of cell A, and then performing PRACH transmission associated with the specific SSB of cell B.

[0094] Another method of triggering PRACH transmission targeting multiple cells including multiple non-serving cells or serving cells through one PDCCH of a base station and performing the PRACH transmission by a terminal may be to perform PRACH transmission through a common PRCH resource. In the case of PRACH transmission through a common PRCH resource, the terminal is allocated a PRACH resource that is associated with multiple SSB resources, a PRACH resource that is associated with multiple cell IDs, or a PRACH radio resource that is designated as a PRACH radio resource targeting multiple cells, such as UL RSRP measurement, and is distinct from the PRACH radio resources used for other purposes. Thereafter, the terminal may be instructed to perform PRACH transmission through the PRACH resource from the serving cell through a PDCCH. When the terminal is allocated a PRACH resource associated with multiple SSB radio resources and is instructed to perform PRACH transmission using the resource, the terminal calculates PRACH transmission power from the SSB radio resources. At this time, the PRACH transmission power can be determined based on the largest value among the calculated values. That is, the PRACH transmission power can be determined based on the largest path loss value measured through the SSB radio resource. This is to ensure that the terminal's PRACH is received in as many non-serving cells as possible.

[0095] Each base station responsible for the serving cell and non-serving cell that received the PRACH performs UL quality measurement and comparison based on the PRACH. A target cell is selected based on the result. Information about the selected target cell can be transmitted to the terminal in RAR format. Alternatively, the network can omit RAR transmission corresponding to the PRACH transmission. In this case, when a handover is finally decided, the serving cell can transmit information about the target cell to the terminal via a handover command or cell switching command.

[0096] ● When the base station transmits information about the target cell to the terminal via RAR, the terminal can recognize that a handover to the target cell has been instructed through reception of the RAR. Information about the target cell can be included in the RAR in the form of a cell ID, SSB index, target PRACH resource index, etc. and transmitted to the terminal.

[0097] In another method of the second method according to an embodiment of the present disclosure, after the base station selects one or more target cells as handover targets, the terminal can estimate the UL quality for each target cell to determine whether to perform a handover. When the base station operates in a manner in which the terminal estimates the UL quality for each target cell to determine whether to perform a handover after selecting one or more target cells as handover targets, the serving cell can first transmit a control message in the form of RRC, MAC CE, DCI, etc., allowing or instructing the terminal to perform a handover decision. Thereafter, the serving cell receives a DL quality measurement report of a non-serving cell, such as a candidate cell of the terminal. Based on the report, the serving cell selects one or more target cells and instructs the terminal to perform a handover to the target cell or to perform a handover to one of the target cells. The terminal receiving the above instruction can compare the pathloss measured through the DL RS or DL ​​channel with the maximum transmission power allowed for each target cell to determine whether to handover to each target cell or select the final target cell to be handed over.

[0098] If the terminal fails to select a suitable target cell for the handover, the terminal may postpone the handover decision. Alternatively, the terminal may transmit a handover rejection message to the serving cell. If the handover decision is postponed, the terminal may subsequently continuously perform a handover suitability check for the indicated target cell or target cells, and if a suitable target cell is subsequently detected, the terminal may transmit a handover request or handover acceptance message along with a target cell indicator to the serving cell. The network may set a maximum postponement period allowed for the above operation, and if the handover request or handover acceptance message from the terminal is not received within the set period, the network determines that the terminal has rejected the handover and cancels the target cell selection. If the terminal fails to detect a suitable target cell for the handover within the set period, the handover operation is aborted.

[0099] The method according to the present disclosure may include a step in which a base station sets or instructs a terminal to measure and report additional information; a step in which the terminal measures and reports basic information and additional information about a candidate cell or a target cell; a step in which the base station instructs a terminal to perform a handover; and the like.

[0100] FIG. 15 is a block diagram illustrating the functional structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0101] Referring to FIG. 15, the terminal may include a terminal receiving unit (1500), a terminal transmitting unit (1510), and a terminal processing unit (control unit) (1505).

[0102] The terminal receiving unit (1500) and the terminal transmitting unit (1510) may be collectively referred to as a transceiver. Depending on the communication method of the terminal described above, the terminal receiving unit (1500), the terminal transmitting unit (1510), and the terminal processing unit (1505) of the terminal may operate. However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more or fewer components (e.g., memory, etc.) than the components described above. In addition, the terminal receiving unit (1500), the terminal transmitting unit (1510), and the terminal processing unit (1505) may be implemented in the form of a single chip.

[0103] The terminal receiving unit (1500) and the terminal transmitting unit (1510) (or, transmitting and receiving unit) can transmit and receive signals with a base station. Here, the signals can include control information and data. To this end, the transmitting and receiving unit can be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts a received signal. However, this is only one embodiment of the transmitting and receiving unit, and the components of the transmitting and receiving unit are not limited to the RF transmitter and RF receiver.

[0104] In addition, the transceiver unit can receive a signal through a wireless channel and output it to the terminal processing unit (1505), and transmit a signal output from the terminal processing unit (1505) through the wireless channel.

[0105] Memory (not shown) can store programs and data necessary for the operation of the terminal. Furthermore, the memory can store control information or data included in signals acquired from the terminal. The memory may be comprised of a storage medium, such as ROM, RAM, a hard disk, CD-ROM, or DVD, or a combination of such storage media.

[0106] The terminal processing unit (1505) can control a series of processes so that the terminal can operate according to the embodiments of the present disclosure described above. The terminal processing unit (1505) can be implemented as a control unit or one or more processors.

[0107] FIG. 16 is a block diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0108] Referring to FIG. 16, the base station may include a base station receiving unit (1600), a base station transmitting unit (1610), and a base station processing unit (control unit) (1605).

[0109] The base station receiving unit (1600) and the base station transmitting unit (1610) may be collectively referred to as a transceiver. Depending on the communication method of the base station described above, the base station receiving unit (1600), the base station transmitting unit (1610), and the base station processing unit (1605) of the base station may operate. However, the components of the base station are not limited to the examples described above. For example, the base station may include more or fewer components (e.g., memory, etc.) than the components described above. In addition, the base station receiving unit (1600), the base station transmitting unit (1610), and the base station processing unit (1605) may be implemented in the form of a single chip.

[0110] The base station receiving unit (1600) and the base station transmitting unit (1610) (or, transmitting and receiving unit) can transmit and receive signals with the terminal. Here, the signals can include control information and data. To this end, the transmitting and receiving unit can be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts a received signal. However, this is only one embodiment of the transmitting and receiving unit, and the components of the transmitting and receiving unit are not limited to the RF transmitter and RF receiver.

[0111] In addition, the transceiver unit can receive a signal through a wireless channel and output it to the base station processing unit (1605), and transmit the signal output from the base station processing unit (1605) through the wireless channel.

[0112] Memory (not shown) can store programs and data necessary for the operation of the base station. Furthermore, the memory can store control information or data contained in signals acquired from the base station. The memory may be comprised of a storage medium, such as ROM, RAM, a hard disk, CD-ROM, or DVD, or a combination of such storage media.

[0113] The base station processing unit (1605) can control a series of processes so that the base station can operate according to the embodiments of the present disclosure described above. The base station processing unit (1605) can be implemented as a control unit or one or more processors.

[0114] Meanwhile, the order of description in the drawings explaining the method of the present disclosure does not necessarily correspond to the order of execution, and the order of precedence may be changed or executed in parallel.

[0115] Alternatively, the drawings illustrating the method of the present disclosure may omit some components and include only some components without detracting from the essence of the present disclosure.

[0116] In addition, the method of the present disclosure may be implemented by combining some or all of the contents included in each embodiment within a scope that does not harm the essence of the disclosure.

[0117] Additionally, although not disclosed in the present disclosure, a method in which a separate table or information including at least one component included in the table proposed in the present disclosure is used is also possible.

[0118] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples presented to easily explain the technical content of the present disclosure and aid in understanding of 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 to which the present disclosure pertains that other modified examples based on the technical concept of the present disclosure are possible. Furthermore, the above-described embodiments may be combined and operated as needed.

Claims

1. In a method of operating a UE (user equipment) in a wireless communication system, A step of receiving, from a serving cell, instruction information indicating transmission of a plurality of physical random access channels (PRACHs) through a physical downlink control channel (PDCCH); When resources that overlap at the same time are allocated to two or more PRACHs among the plurality of PRACHs indicated above, a step of identifying priorities between PRACHs to which the overlapping resources are allocated; and A method comprising the step of performing a transmission for a PRACH having the highest priority.

2. In paragraph 1, The instruction information indicating the above multiple PRACH transmissions is: A method comprising an index indicating an SSB (synchronization signal block) corresponding to each of the plurality of PRACHs.

3. In paragraph 1, The above priorities are: A method for identifying a plurality of PRACHs based on at least one of the transmission required power and the maximum allowable power.

4. In paragraph 1, The instruction information indicating the above multiple PRACH transmissions is: Contains information indicating common PRACH resources for multiple cells, The above common PRACH resources are: A method associated with at least one of a plurality of SSB resources, a plurality of cell IDs (identifications) and an uplink RSRP (reference signal received power) measurement result.

5. In paragraph 4, A step of measuring path loss through radio resources allocated to SSB for each of the plurality of cells to which the common PRACH resources are allocated; and A method further comprising the step of identifying a PRACH transmission power based on the largest path loss among the measured path losses.

6. In paragraph 4, A method in which transmission of a RAR (random access response) message is omitted.

7. In paragraph 1, A method further comprising the step of transmitting a quality report for a downlink beam and / or a transmission configuration indicator (TCI) and an uplink quality report associated with the downlink beam and / or TCI to the serving cell.

8. In paragraph 1, A method further comprising the step of transmitting an uplink quality report to the serving cell only when a preset reporting condition is satisfied.

9. For 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: Receives instruction information indicating transmission of multiple PRACHs (physical random access channels) from a serving cell through a PDCCH (physical downlink control channel), When resources that overlap at the same time are allocated to two or more PRACHs among the above-indicated plurality of PRACHs, the priority between the PRACHs to which the overlapping resources are allocated is identified, A UE that performs transmission on the PRACH with the highest priority.

10. In paragraph 9, The instruction information indicating the above multiple PRACH transmissions is: A UE including an index indicating a synchronization signal block (SSB) corresponding to each of the plurality of PRACHs.

11. In paragraph 9, The above priorities are: A UE identified based on at least one of the transmission requested power and maximum allowed power of each of the plurality of PRACHs.

12. In paragraph 9, The instruction information indicating the above multiple PRACH transmissions is: Contains information indicating common PRACH resources for multiple cells, The above common PRACH resources are: A UE associated with at least one of multiple SSB resources, multiple cell IDs (identifications) and uplink RSRP (reference signal received power) measurement results.

13. In paragraph 12, The above commands cause the UE to: For each of the plurality of cells to which the common PRACH resources are allocated, path loss is measured through the radio resources allocated to SSB, A UE that identifies the PRACH transmission power based on the largest path loss among the measured path losses.

14. In paragraph 12, UE that skips transmission of RAR (random access response) message.

15. In paragraph 9, The above commands cause the UE to: A UE configured to transmit a quality report for a downlink beam and / or a transmission configuration indicator (TCI) and an uplink quality report associated with the downlink beam and / or TCI together to the serving cell.

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