Method and device for power headroom reporting of sounding reference signal for power imbalance indication in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. An operation method of a base station in a wireless communication system according to an embodiment of the present disclosure may comprise the steps of: transmitting, to a user equipment (UE), sounding reference signal (SRS) configuration information including an SRS resource set including a plurality of SRS resources for SRS antenna switching; performing SRS antenna switching on a plurality of reception antenna ports of the UE and receiving SRSs transmitted with the same transmission power; transmitting a downlink reference signal to the UE by using a downlink reference signal resource associated with the SRS antenna switching; receiving a measurement report including a reception power measured for each of the plurality of reception antenna ports of the UE; and identifying an insertion loss (IL) imbalance of the UE by comparing a reception power of the SRS transmitted using each of the plurality of reception antenna ports of the UE with the reception power measured for each of the plurality of reception antenna ports of the UE and included in the measurement report.

Description

Method and apparatus for reporting power headroom of a sounding reference signal for power imbalance indication in a wireless communication system

[0001] The present disclosure relates to the operation of a terminal and a base station in a wireless communication system. Specifically, the present disclosure relates to a method in which a terminal reports power headroom and additional information to a base station to improve the channel estimation accuracy of the base station during enhanced downlink channel estimation based on SRS antenna switching, and to an apparatus capable of performing the same.

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

[0003] In the early stages of 5G mobile communication technology, aiming to satisfy service support and performance requirements for enhanced Mobile BroadBand (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), technologies such as beamforming and Massive MIMO to mitigate path loss and increase transmission distance in ultra-high frequency bands, support for various numerologies (such as the operation of multiple subcarrier spacings) and dynamic operation of slot formats for the efficient utilization of ultra-high frequency resources, initial access techniques to support multi-beam transmission and broadband, definition and operation of Band-Width Parts (BWP), Low Density Parity Check (LDPC) codes for high-volume data transmission, new channel coding methods such as Polar Codes for the reliable transmission of control information, and L2 pre-processing (L2 Standardization has been carried out for pre-processing, network slicing which provides a dedicated network specialized for specific services, and other methods.

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

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

[0006] When such 5G mobile communication systems are commercialized, connected devices, which are increasing explosively, will be connected to communication networks. Accordingly, it is expected that there will be a need to enhance the functionality and performance of 5G mobile communication systems and to integrate the operation of connected devices. To this end, new research is planned to be conducted on 5G performance improvement and complexity reduction, support for AI services, support for metaverse services, and drone communication using eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] Furthermore, the advancement of these 5G mobile communication systems encompasses multi-antenna transmission technologies such as new waveforms to guarantee coverage in the terahertz band of 6G mobile communication technology, Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas; metamaterial-based lenses and antennas to improve terahertz band signal coverage; high-dimensional spatial multiplexing technology using OAM (Orbital Angular Momentum); and Reconfigurable Intelligent Surface (RIS) technology; as well as Full Duplex technology for enhancing frequency efficiency and system networks in 6G mobile communication technology; AI-based communication technologies that realize system optimization by utilizing satellites and AI from the design stage and internalizing end-to-end AI support functions; and the realization of services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources. It could serve as a foundation for the development of next-generation distributed computing technologies.

[0008] The disclosed embodiments aim to provide an apparatus and method capable of effectively providing services in a mobile communication system.

[0009] A method of operation of a base station in a wireless communication system according to one embodiment of the present disclosure may include: transmitting SRS configuration information to a UE (user equipment) including an SRS resource set containing a plurality of SRS resources for sounding reference signal (SRS) antenna switching; receiving an SRS transmitted with the same transmission power by performing SRS antenna switching on a plurality of receiving antenna ports of the UE; transmitting a downlink reference signal to the UE using a downlink reference signal resource associated with the SRS antenna switching; receiving a measurement report including received power measured for each of the plurality of receiving antenna ports of the UE; and comparing the received power of the SRS transmitted for each of the plurality of receiving antenna ports of the UE with the received power measured for each of the plurality of receiving antenna ports of the UE included in the measurement report to identify an insertion loss (IL) imbalance of the UE.

[0010] The disclosed embodiments provide an apparatus and method capable of effectively providing services in a mobile communication system.

[0011] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0012] FIG. 1 is a diagram showing the sounding reference signal (SRS) antenna switching operation in a wireless communication system according to one embodiment of the present disclosure.

[0013] FIG. 2 is an example comparing a method for estimating a downlink channel based on a channel state information-reference signal (CSI-RS) and a method for estimating a downlink channel based on SRS and reciprocity in a wireless communication system according to one embodiment of the present disclosure.

[0014] FIG. 3 illustrates an example of a case in which, in a wireless communication system according to one embodiment of the present disclosure, when a terminal supports 1T4R, the terminal performs SRS antenna switching so that the base station acquires a downlink channel.

[0015] FIG. 4 is a diagram showing an example of a terminal structure supporting four receiving antennas in a wireless communication system according to one embodiment of the present disclosure.

[0016] FIG. 5 shows an example of a case in which a terminal receives CSI-RS from a base station and calculates CSI-RSRP in a wireless communication system according to one embodiment of the present disclosure.

[0017] FIG. 6 illustrates an example in which a terminal performs 1T2R SRS antenna switching using each antenna in a wireless communication system according to one embodiment of the present disclosure.

[0018] FIG. 7 illustrates an example of a case in which a terminal receives CSI-RS transmitted by a base station to two antenna ports in a wireless communication system according to one embodiment of the present disclosure, measures RSRP, and reports it at each antenna port.

[0019] FIG. 8 illustrates a process for inferring power imbalance that occurs when a terminal transmits SRS resources using RSRP values ​​for each antenna of the terminal reported by the terminal in a wireless communication system according to one embodiment of the present disclosure, and RSRP values ​​of SRS resources measured by a base station and RSRP values ​​of the terminal reported by the terminal.

[0020] FIG. 9 is an example for explaining the process of a terminal estimating power imbalance for SRS AS through the steps of Step 1 to Step 6 in a wireless communication system according to one embodiment of the present disclosure.

[0021] FIG. 10 illustrates an example of a MAC CE format for transmitting the reception strength of each SRS resource received by a base station to a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0022] FIG. 11 is a drawing illustrating the structure of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0023] FIG. 12 is a drawing illustrating the structure of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0024] A method of operation of a base station in a wireless communication system according to one embodiment of the present disclosure may include: transmitting SRS configuration information to a UE (user equipment) including an SRS resource set containing a plurality of SRS resources for sounding reference signal (SRS) antenna switching; receiving an SRS transmitted with the same transmission power by performing SRS antenna switching on a plurality of receiving antenna ports of the UE; transmitting a downlink reference signal to the UE using a downlink reference signal resource associated with the SRS antenna switching; receiving a measurement report including received power measured for each of the plurality of receiving antenna ports of the UE; and identifying an insertion loss (IL) imbalance of the UE by comparing the received power of the SRS transmitted for each of the plurality of receiving antenna ports of the UE with the received power measured for each of the plurality of receiving antenna ports of the UE included in the measurement report.

[0025] A method of operation of user equipment (UE) in a wireless communication system according to another embodiment of the present disclosure comprises: receiving SRS configuration information from a base station, the SRS resource set including a plurality of SRS resources for sounding reference signal (SRS) antenna switching; mapping the SRS resources included in the SRS resource set to a plurality of receiving antenna ports of the UE based on the SRS configuration information; performing SRS antenna switching for the plurality of receiving antenna ports to transmit the SRS with the same transmission power; receiving a downlink reference signal transmitted from the base station using a downlink reference signal resource associated with the SRS antenna switching through the plurality of receiving antenna ports; measuring the receiving power of the downlink reference signal for each of the plurality of receiving antenna ports; and transmitting a measurement report including the receiving power measured for each of the plurality of receiving antenna ports to the base station.

[0026] A base station according to another embodiment of the present disclosure comprises: at least one transceiver; and at least one processor communicatively coupled to the at least one transceiver; and includes at least one memory that is communiquently coupled to the at least one processor and stores instructions, wherein the instructions are executed by the at least one processor individually or in any combination, and the base station transmits SRS configuration information to a UE (user equipment) including an SRS resource set containing a plurality of SRS resources for sounding reference signal (SRS) antenna switching, performs SRS antenna switching for a plurality of receiving antenna ports of the UE to receive an SRS transmitted with the same transmit power, transmits a downlink reference signal to the UE using a downlink reference signal resource associated with the SRS antenna switching, receives a measurement report including the received power measured for each of the plurality of receiving antenna ports of the UE, and compares the received power of the SRS transmitted for each of the plurality of receiving antenna ports of the UE with the received power measured for each of the plurality of receiving antenna ports of the UE included in the measurement report, thereby the insertion loss (IL) of the UE It can be made to identify imbalance.

[0027] In a user equipment (UE) according to another embodiment of the present disclosure: at least one transceiver; at least one processor communicatively coupled to the at least one transceiver; and includes at least one memory that is communiquently coupled to the at least one processor and stores instructions, wherein the instructions are executed by the at least one processor individually or in any combination, and the UE receives SRS configuration information from a base station, the SRS resource set including a plurality of SRS resources for sounding reference signal (SRS) antenna switching, and based on the SRS configuration information, maps the SRS resources included in the SRS resource set to a plurality of receiving antenna ports of the UE, performs SRS antenna switching for the plurality of receiving antenna ports to transmit the SRS with the same transmit power, receives a downlink reference signal transmitted from the base station using a downlink reference signal resource associated with the SRS antenna switching through the plurality of receiving antenna ports, measures the received power of the downlink reference signal for each of the plurality of receiving antenna ports, and provides a measurement report including the received power measured for each of the plurality of receiving antenna ports. It can be transmitted to the base station.

[0028] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0029] In describing the embodiments, technical details that are well known in the art to which this disclosure belongs and are not directly related to this disclosure are omitted. This is intended to convey the essence of this disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0030] For the same reason, some components in the attached drawings have been exaggerated, omitted, or schematically depicted. Additionally, the dimensions of each component do not entirely reflect their actual dimensions. Identical or corresponding components in each drawing have been assigned the same reference numbers.

[0031] The advantages and features of the present disclosure, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components. Furthermore, in describing the present disclosure, if it is determined that a detailed description of a related function or configuration might unnecessarily obscure the essence of the present disclosure, such detailed description is omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or conventions of the user or operator. Therefore, their definitions should be based on the content throughout the specification.

[0032] Hereinafter, a base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, eNode B, Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. A terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. In this disclosure, a downlink (DL) refers to a wireless transmission path of a signal transmitted by a base station to a terminal, and an uplink (UL) refers to a wireless transmission path of a signal transmitted by a terminal to a base station. Furthermore, while LTE or LTE-A systems may be described as examples below, embodiments of this disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, 5th generation mobile communication technologies (5G, new radio, NR) developed after LTE-A may be included therein, and the 5G below may be a concept that includes existing LTE, LTE-A, and other similar services. In addition, the present disclosure may be applied to other communication systems with some modifications made at the discretion of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure. The contents of the present disclosure are applicable to FDD and TDD systems.

[0033] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0034] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to their corresponding functions.

[0035] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and 'parts' may be implemented to utilize one or more CPUs within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors.

[0036] In describing the present disclosure below, if it is determined that a detailed description of related known functions or configurations could unnecessarily obscure the essence of the present disclosure, such detailed description will be omitted. Embodiments of the present disclosure may be described below with reference to the attached drawings.

[0037] Wireless communication systems are evolving from providing early voice-oriented services to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards like 3GPP’s HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2’s HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE’s 802.16e.

[0038] As a representative example of the above-mentioned broadband wireless communication system, the LTE system employs the Orthogonal Frequency Division Multiplexing (OFDM) method for the downlink (DL) and the Single Carrier Frequency Division Multiple Access (SC-FDMA) method for the uplink (UL). The uplink refers to a wireless link through which a terminal (User Equipment (UE) or Mobile Station (MS)) transmits data or control signals to a base station (eNode B, or base station (BS)), and the downlink refers to a wireless link through which a base station transmits data or control signals to a terminal. The above-mentioned multiple access method can distinguish the data or control information of each user by allocating and operating time-frequency resources to be sent for each user so that they do not overlap, that is, so that orthogonality is established.

[0039] As a future communication system following LTE, for example, a 5G communication system must be able to freely reflect the diverse requirements of users and service providers, and therefore, services that satisfy various requirements simultaneously must be supported. Services being considered for a 5G communication system include enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC).

[0040] eMBB aims to provide data transmission speeds that are superior to those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to provide a peak data rate of 20 Gbps in the downlink and 10 Gbps in the uplink from the perspective of a single base station. Furthermore, while providing these peak data rates, the 5G communication system must also provide an increased user-perceived data rate. To satisfy these requirements, it necessitates improvements in various transmission and reception technologies, including enhanced Multi-Input Multi-Output (MIMO) transmission technology. Additionally, while LTE transmits signals using a maximum bandwidth of 20 MHz in the 2 GHz band, the 5G communication system can meet the data transmission speeds required by using a frequency bandwidth wider than 20 MHz in frequency bands of 3–6 GHz or above 6 GHz.

[0041] Simultaneously, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide IoT, mMTC requires support for a large number of terminal connections within a cell, improved terminal coverage, enhanced battery life, and reduced terminal costs. Since IoT devices are attached to various sensors and equipment to provide communication functions, the system must be able to support a large number of terminals within a cell (e.g., 1,000,000 terminals / km²). Furthermore, due to the nature of the service, terminals supporting mMTC are likely to be located in dead zones not covered by cells, such as building basements; therefore, they may require wider coverage compared to other services provided by 5G communication systems. Terminals supporting mMTC must consist of low-cost devices, and since it is difficult to frequently replace terminal batteries, a very long battery life of 10 to 15 years may be required.

[0042] Finally, URLLC is a mission-critical cellular-based wireless communication service. For example, consider services used for remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts. Therefore, the communication provided by URLLC must offer very low latency and very high reliability. For instance, services supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds, and simultaneously 10 -5The following packet error rate requirements apply. Therefore, for services supporting URLLC, 5G systems must provide a Transmit Time Interval (TTI) smaller than other services, and at the same time, design considerations may be required to allocate a wide resource in the frequency band to ensure the reliability of the communication link.

[0043] The three 5G services (e.g., eMBB, URLLC, mMTC) can be multiplexed and transmitted within a single system. In this case, different transmission and reception techniques and parameters may be used between the services to satisfy the different requirements of each service. Of course, 5G is not limited to the three services mentioned above.

[0044] Hereinafter, a / b may be understood as at least one of a or b. Additionally, upper signaling may be understood as upper layer signaling or upper layer signal.

[0045] [Uplink: RS]

[0046] [Regarding SRS]

[0047] A method for estimating an uplink channel using the transmission of a terminal's Sounding Reference Signal (SRS) is described. To transmit configuration information for SRS transmission to the terminal, the base station may set at least one SRS configuration for each uplink BWP, and may also set at least one SRS resource set for each SRS configuration. For example, the base station and the terminal may exchange upper-level signaling information as follows to transmit information regarding the SRS resource set.

[0048] - srs-ResourceSetId: SRS resource set index

[0049] - srs-ResourceIdList: A set of SRS resource indices referenced by the SRS resource set

[0050] - resourceType: This is the time-axis transmission setting for the SRS resource referenced in the SRS resource set, and can be set to one of 'periodic', 'semi-persistent', or 'aperiodic'. If set to 'periodic' or 'semi-persistent', associated CSI-RS information may be provided depending on the usage of the SRS resource set. If set to 'aperiodic', a non-periodic SRS resource trigger list and slot offset information may be provided, and associated CSI-RS information may be provided depending on the usage of the SRS resource set.

[0051] - usage: A setting regarding the usage of the SRS resource referenced in the SRS resource set, which can be set to one of 'beamManagement', 'codebook', 'nonCodebook', or 'antennaSwitching'.

[0052] - alpha, p0, pathlossReferenceRS, srs-PowerControlAdjustmentStates: Provides parameter settings for controlling the transmit power of the SRS resource referenced in the SRS resource set.

[0053] The terminal can understand that the SRS resources included in the set of SRS resource indices referenced in the SRS resource set follow the information set in the SRS resource set.

[0054] Additionally, the base station and the terminal may transmit and receive upper-layer signaling information to convey individual configuration information for the SRS resource. For example, the individual configuration information for the SRS resource may include time-frequency axis mapping information within the slot of the SRS resource, which may include information regarding frequency hopping within or between slots of the SRS resource. Furthermore, the individual configuration information for the SRS resource may include the time-axis transmission setting of the SRS resource, which may be set to one of 'periodic', 'semi-persistent', or 'aperiodic'. This may be restricted to having the same time-axis transmission setting as the SRS resource set containing the SRS resource. If the time-axis transmission setting of the SRS resource is set to 'periodic' or 'semi-persistent', the SRS resource transmission period and slot offset (e.g., periodicityAndOffset) may additionally be included in the time-axis transmission setting.

[0055] A base station may enable, deactivate, or trigger SRS transmission to a terminal via upper-layer signaling, including RRC signaling or MAC CE signaling, or L1 signaling (e.g., DCI). For example, a base station may enable or deactivate periodic SRS transmission to a terminal via upper-layer signaling. A base station may instruct an SRS resource set with resourceType set to periodic to be enabled via upper-layer signaling, and the terminal may transmit an SRS resource referenced in the enabled SRS resource set. The time-frequency axis resource mapping within the slot of the transmitted SRS resource may follow the resource mapping information set in the SRS resource, and the slot mapping, including the transmission period and slot offset, may follow the periodicityAndOffset set in the SRS resource. Additionally, a spatial domain transmission filter applied to the transmitted SRS resource may refer to spatial relation info set in the SRS resource, or may refer to associated CSI-RS information set in the SRS resource set containing the SRS resource. The terminal can transmit an SRS resource within an active uplink BWP for a periodic SRS resource activated through upper layer signaling.

[0056] For example, a base station can enable or disable semi-persistent SRS transmission to a terminal via upper-layer signaling. The base station can instruct the terminal to enable an SRS resource set via MAC CE signaling, and the terminal can transmit an SRS resource referenced in the enabled SRS resource set. The SRS resource set enabled via MAC CE signaling may be limited to an SRS resource set where the resourceType is set to semi-persistent. The time-frequency axis resource mapping within the slot of the SRS resource transmitted by the terminal may follow the resource mapping information set in the SRS resource, and the slot mapping, including the transmission period and slot offset, may follow the periodicityAndOffset set in the SRS resource. Additionally, the spatial domain transmission filter applied to the SRS resource transmitted by the terminal may refer to the spatial relation info set in the SRS resource, or refer to the associated CSI-RS information set in the SRS resource set containing the SRS resource. If spatial relation info is configured in the SRS resource, the terminal may determine the spatial domain transmission filter by referring to the configuration information regarding the spatial relation info transmitted via MAC CE signaling that enables semi-persistent SRS transmission, without adhering to this. The terminal may transmit the SRS resource within the uplink BWP enabled for the semi-persistent SRS resource activated via upper layer signaling.

[0057] For example, a base station can trigger an aperiodic SRS transmission to a terminal via the DCI. The base station can indicate one of the aperiodic SRS resource triggers (aperiodicSRS-ResourceTrigger) through the SRS request field of the DCI. The terminal can understand that among the configuration information of the SRS resource set, an SRS resource set containing the aperiodic SRS resource trigger indicated via the DCI from the list of aperiodic SRS resource triggers has been triggered. The terminal can transmit the SRS resource referenced in the triggered SRS resource set. The time-frequency axis resource mapping within the slot of the SRS resource transmitted by the terminal may follow the resource mapping information set in the SRS resource. Additionally, the slot mapping of the SRS resource transmitted by the terminal may be determined through the slot offset between the PDCCH containing the DCI and the SRS resource, which may refer to the value(s) included in the set of slot offsets set in the SRS resource set. Specifically, the slot offset between the PDCCH containing the DCI and the SRS resource may be the value specified in the time domain resource assignment field of the DCI among the offset value(s) included in the slot offset set configured in the SRS resource set. Additionally, the spatial domain transmission filter applied to the SRS resource transmitted by the terminal may refer to the spatial relation info configured in the SRS resource, or may refer to the associated CSI-RS information configured in the SRS resource set containing the SRS resource.The terminal can transmit an SRS resource within an uplink BWP that is enabled for a non-periodic SRS resource triggered via DCI.

[0058] When a base station triggers aperiodic SRS transmission to a terminal via DCI, a minimum time interval may be required between the PDCCH containing the DCI triggering the aperiodic SRS transmission and the transmitted SRS so that the terminal can apply configuration information for the SRS resource and transmit the SRS. The time interval for the terminal's SRS transmission can be defined as the number of symbols between the last symbol of the PDCCH containing the DCI triggering the aperiodic SRS transmission and the first symbol mapped to the first transmitted SRS resource(s). The minimum time interval can be determined by referencing the PUSCH preparation procedure time required for the terminal to prepare for PUSCH transmission. Additionally, the minimum time interval may have different values ​​depending on the usage of the SRS resource set containing the transmitted SRS resource. For example, the minimum time interval can be determined by N2 symbols defined by considering the terminal's processing capability based on the terminal's capability, referencing the terminal's PUSCH preparation procedure time. In addition, considering the usage of the SRS resource set including the SRS resource transmitted by the terminal, if the usage of the SRS resource set is set to 'codebook' or 'antennaSwitching', the minimum time interval can be set to N2 symbols, and if the usage of the SRS resource set is set to 'nonCodebook' or 'beamManagement', the minimum time interval can be set to N2+14 symbols.The terminal transmits an aperiodic SRS when the time interval for the aperiodic SRS transmission is greater than or equal to the minimum time interval, and can ignore the DCI that triggers the aperiodic SRS when the time interval for the aperiodic SRS transmission is less than the minimum time interval.

[0059]

[0060]

[0061] The spatialRelationInfo setting information in [Table 1] above can be applied to the beam used for SRS transmission by referencing a single reference signal and the beam information of that reference signal. For example, the spatialRelationInfo setting may include information such as that shown in [Table 2] below. However, it is not limited to such examples.

[0062]

[0063] Referring to the spatialRelationInfo setting above, the terminal can receive a CSI-RS index or an SRS index as the index of the reference signal to be referenced from the base station in order to use beam information of a specific reference signal, i.e., the SS / PBCH block index. The upper signaling referenceSignal is setting information indicating which reference signal beam information to reference for the corresponding SRS transmission, and ssb-Index may mean the SS / PBCH block index, csi-RS-Index may mean the CSI-RS index, and srs may mean the SRS index. If the value of the upper signaling referenceSignal is set to 'ssb-Index', the terminal can apply the receiving beam used when receiving the SS / PBCH block corresponding to ssb-Index as the transmitting beam for the corresponding SRS transmission. If the value of the upper signaling referenceSignal is set to 'csi-RS-Index', the terminal can apply the receiving beam used when receiving the CSI-RS corresponding to csi-RS-Index as the transmitting beam for the corresponding SRS transmission. If the value of the upper signaling referenceSignal is set to 'srs', the terminal can apply the transmission beam used during the transmission of the SRS corresponding to srs as the transmission beam for the transmission of the SRS.

[0064] [SRS: Antenna switching]

[0065] The following describes the SRS for antenna switching.

[0066] The SRS transmitted from the terminal can be used by the base station to acquire Channel State Information (DL CSI) information (e.g., DL CSI acquisition). As a specific example, in a single-cell or multi-cell (e.g., carrier aggregation (CA)) situation based on Time Division Duplex (TDD), the Base Station (BS) can measure the SRS transmitted from the UE after scheduling the transmission of the SRS to the User Equipment (UE). In this case, the base station can assume reciprocity between the DL (downlink) and UL (uplink) channels and consider the uplink channel information estimated based on the SRS transmitted from the terminal as downlink channel information, and use this to perform scheduling of downlink signals / channels for the terminal. At this time, the terminal can receive a setting from the base station for the use of the SRS for acquiring downlink channel information as antenna switching.

[0067] For example, according to the standard (e.g., 3gpp TS38.214), the use of the SRS can be configured for the base station and / or terminal using a higher layer parameter (e.g., the usage of the RRC parameter SRS-ResourceSet). Here, the use of the SRS can be configured for beam management, codebook transmission, non-codebook transmission, antenna switching, etc.

[0068] As described above, if the terminal receives the parameter 'usage' within the upper layer signaling SRS-ResourceSet from the base station as 'antennaSwitching', the terminal may receive at least one upper layer signaling setting from the base station according to the reported terminal capability. In this case, the terminal may report 'supportedSRS-TxPortSwitch' as ​​the terminal capability, and the value may be as follows. In the following, 'mTnR' may refer to the terminal capability to support transmission through m antennas and reception through n antennas.

[0069] - 't1r2': A terminal capability report value indicating that the terminal is capable of 1T2R operation

[0070] - 't1r1-t1r2': A terminal capability report value indicating that the terminal is capable of 1T1R or 1T2R operation

[0071] - 't2r4': A terminal capability report value indicating that the terminal is capable of 2T4R operation.

[0072] - 't1r4': A terminal capability report value indicating that the terminal is capable of 1T4R operation

[0073] - 't1r6': A terminal capability report value indicating that the terminal is capable of 1T6R operation

[0074] - 't1r8': A terminal capability report value indicating that the terminal is capable of 1T8R operation

[0075] - 't2r6': A terminal capability report value indicating that the terminal is capable of 2T6R operation

[0076] - 't2r8': A terminal capability report value indicating that the terminal is capable of 2T8R operation

[0077] - 't4r8': A terminal capability report value indicating that the terminal is capable of 4T8R operation.

[0078] - 't1r1-t1r2-t1r4': A terminal capability report value indicating that the terminal is capable of 1T1R, 1T2R, or 1T4R operation.

[0079] - 't1r4-t2r4': A terminal capability report value indicating that the terminal is capable of 1T4R or 2T4R operation.

[0080] - 't1r1-t1r2-t2r2-t2r4': A terminal capability report value indicating that the terminal is capable of 1T1R, 1T2R, 2T2R, or 2T4R operations.

[0081] - 't1r1-t1r2-t2r2-t1r4-t2r4': A terminal capability report value indicating that the terminal is capable of 1T1R, 1T2R, 2T2R, 1T4R, or 2T4R operations.

[0082] - 't1r1': A terminal capability report value indicating that the terminal is capable of 1T1R operation

[0083] - 't2r2': A terminal capability report value indicating that the terminal is capable of 2T2R operation.

[0084] - 't1r1-t2r2': A terminal capability report value indicating that the terminal is capable of 1T1R or 2T2R operation.

[0085] - 't4r4': A terminal capability report value indicating that the terminal is capable of 4T4R operation.

[0086] - 't1r1-t2r2-t4r4': A terminal capability report value indicating that the terminal is capable of 1T1R, 2T2R, or 4T4R operation.

[0087] FIG. 1 is a diagram showing the SRS antenna switching operation in a wireless communication system according to one embodiment of the present disclosure.

[0088] Referring to FIG. 1, the terminal may be in a situation where it operates in 1T4R and has received two non-periodic SRS resource sets (e.g., SRS resource set #0 and #1). The terminal receives a PDCCH from a base station (100) and may be instructed to trigger a non-periodic SRS for SRS resource set #0 (110) and SRS resource set #1 (120) through the PDCCH. At this time, the slot offset value for SRS resource set #0 (110) may be set to slotOffset, which is an upper layer signaling, and the value may be 1. Additionally, the terminal may perform a non-periodic SRS transmission for SRS resource set #0 at a position one slot after the slot in which the PDCCH was received (e.g., at slot #1). Additionally, the slot offset value for SRS resource set #1 (120) may be set to slotOffset, which is an upper layer signaling, and the value may be 2. Additionally, the terminal can perform a non-periodic SRS transmission for SRS resource set #1 at a position two slots after the slot in which the PDCCH was received (e.g., at slot #2).

[0089] SRS resource #0 (111) and SRS resource #1 (112) included in SRS resource set #0 (110) can be transmitted at different OFDM symbol locations within slot #1, and there may be Y number of OFDM symbols as a guard interval between SRS resource #0 and #1 (113). Additionally, when transmitting for SRS resource #0 (130), the terminal can perform SRS transmission by connecting one SRS port to the terminal's first receiving antenna port (135). When transmitting for SRS resource #1 (140), the terminal can perform SRS transmission by connecting one SRS port to the terminal's second receiving antenna port (145).

[0090] SRS resource #2 (121) and SRS resource #3 (122) included in SRS resource set #1 (120) are transmitted at different OFDM symbol locations within slot #1, and there may be Y number of OFDM symbols as a guard interval between SRS resource #2 and #3 (123). Additionally, when transmitting for SRS resource #2 (150), the terminal can perform SRS transmission by connecting one SRS port to the terminal's third receiving antenna port (155). When transmitting for SRS resource #3 (160), the terminal can perform SRS transmission by connecting one SRS port to the terminal's fourth receiving antenna port (165).

[0091] By connecting the four SRS resources #0 to #3 described above to the receiving antenna ports of different terminals and transmitting SRS, the terminal can transmit SRS from all different receiving antenna ports so that it can acquire channel information connected to all receiving antennas of the terminal. In addition, by the terminal transmitting SRS from all different receiving antenna ports, the base station can acquire channel information between the base station and the terminal and utilize it for uplink or downlink scheduling.

[0092] [UE capability]

[0093] [Regarding Terminal Capability Reporting]

[0094] In LTE and NR, a terminal can perform a procedure to report the capabilities supported by the terminal to the base station while connected to the serving base station. In the description below, this is referred to as a UE capability report.

[0095] A base station may transmit a UE capability enquiry message requesting a capability report to a connected terminal. The UE capability enquiry message may include a request for a terminal capability specific to the base station's RAT (radio access technology) type. The request for a terminal capability specific to the RAT type may include information such as supported frequency band combinations. Furthermore, in the case of the UE capability enquiry message, multiple UE capabilities for each RAT type may be requested through a single RRC message container transmitted by the base station, or the base station may transmit the UE capability enquiry message, which includes a request for a terminal capability for each RAT type, to the terminal multiple times. That is, the UE capability inquiry may be repeated multiple times within a single message, and the terminal may construct a corresponding UE capability information message and report it multiple times. In next-generation mobile communication systems, a UE capability request can be made for NR, LTE, EN-DC (E-UTRA - NR dual connectivity), and MR-DC (Multi-RAT dual connectivity). In addition, the above terminal capability inquiry message can generally be transmitted initially after the terminal is connected to the base station, but the base station may also request it under any conditions when necessary.

[0096] According to one embodiment, a terminal that receives a request to report UE capability from a base station can configure terminal capability according to the RAT type and band information requested from the base station. The method by which a terminal configures UE capability in an NR system may be as follows.

[0097] 1. If the terminal receives a list of LTE and / or NR bands from the base station via a UE capability request, the terminal can configure a band combination (BC) for EN-DC and NR stand alone (SA). That is, it can configure a candidate list of BCs for EN-DC and NR SA based on the bands requested from the base station via FreqBandList. Additionally, the bands may have priority in the order listed in FreqBandList.

[0098] 2. If the base station requests a UE capability report by setting the “eutra-nr-only” flag or the “eutra” flag, the terminal may completely remove NR SA BCs from the list of candidate BCs configured. This action may occur only when the LTE base station (eNB) requests the “eutra” capability.

[0099] 3. Subsequently, the terminal may remove fallback BCs from the candidate list of BCs configured in the above step. Here, a fallback BC refers to a BC that can be obtained by removing a band corresponding to at least one SCell from any BC; this step may be omitted because the BC before removing the band corresponding to at least one SCell already covers the fallback BC. This step applies to MR-DC as well, meaning it can also be applied to LTE bands. The BCs remaining after this step may be the final "candidate BC list."

[0100] 4. The terminal can select BCs to report by selecting BCs that match the requested RAT type from the final "Candidate BC List" above. In this step, the terminal can configure the supportedBandCombinationList in a predetermined order. That is, the terminal can configure the BCs and UE capabilities to report according to the pre-configured rat-Type order (nr -> eutra-nr -> eutra). Additionally, it can configure a featureSetCombination for the configured supportedBandCombinationList and construct a list of "Candidate Feature Set Combinations" from the Candidate BC List from which the list of fallback BCs (containing capabilities of the same or lower level) has been removed. The above "Candidate Feature Set Combinations" include feature set combinations for both NR and EUTRA-NR BCs and can be obtained from feature set combinations of the UE-NR-Capabilities and UE-MRDC-Capabilities containers.

[0101] 5. Additionally, if the requested rat Type is eutra-nr and has an influence, featureSetCombinations can be included in both the UE-MRDC-Capabilities and UE-NR-Capabilities containers. However, the NR feature set can only be included in UE-NR-Capabilities.

[0102] After terminal capability is configured, the terminal can transmit a terminal capability information message containing the terminal capability to the base station. Based on the terminal capability received from the terminal, the base station can subsequently perform appropriate scheduling and transmission / reception management for the terminal.

[0103] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The contents of the present disclosure are applicable to FDD and TDD systems. In the present disclosure, upper signaling (or upper layer signaling) is a signal transmission method transmitted from a base station to a terminal using a physical layer downlink data channel, or from a terminal to a base station using a physical layer uplink data channel, and may be referred to as RRC signaling, PDCP signaling, or a MAC (medium access control) control element (MAC CE).

[0104] In the present disclosure, when determining whether cooperative communication is applied, the terminal may use various methods, such as the PDCCH(s) that allocate the PDSCH to which cooperative communication is applied having a specific format, or the PDCCH(s) that allocate the PDSCH to which cooperative communication is applied including a specific indicator indicating whether cooperative communication is applied, or the PDCCH(s) that allocate the PDSCH to which cooperative communication is applied being scrambled with a specific RNTI, or assuming the application of cooperative communication in a specific section indicated to an upper layer. For convenience of explanation thereafter, the case in which the terminal receives a PDSCH to which cooperative communication is applied based on conditions similar to those above will be referred to as the NC-JT case.

[0105] In the following disclosure, determining the priority between A and B may be referred to in various ways, such as selecting the one with the higher priority according to a predetermined priority rule and performing the corresponding action, or omitting or dropping the action for the one with the lower priority.

[0106] In the following disclosure, the examples are described through a number of embodiments, but these are not independent, and one or more embodiments may be applied simultaneously or in combination.

[0107] For convenience in the following description of the present disclosure, cells, transmission points, panels, beams, and / or transmission directions that can be distinguished through upper layer / L1 parameters such as TCI state or spatial relation information, or indicators such as cell ID, TRP ID, and panel ID, may be described uniformly as TRP (transmission reception point), beam, or TCI state. Therefore, in actual application, TRP, beam, or TCI state can be appropriately replaced with one of the above terms.

[0108] Hereinafter, the base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, gNB, eNode B, Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. The terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. Although embodiments of the present disclosure are described below using a 5G system as an example, embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types. For example, LTE or LTE-A mobile communication and mobile communication technologies developed after 5G may be included therein. Accordingly, embodiments of the present disclosure may be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure, as judged by a person skilled in the art. The contents of the present disclosure are applicable to FDD and TDD systems.

[0109] In describing the present disclosure below, the term "upper layer signaling" may refer to a signaling corresponding to at least one or a combination of at least one of the following signalings.

[0110] - MIB (Master Information Block)

[0111] - SIB (System Information Block) or SIB

[0112] - RRC (Radio Resource Control)

[0113] - MAC (Medium Access Control) CE (Control Element)

[0114] In addition, L1 signaling may be a signaling corresponding to at least one or a combination of at least one of a signaling method using a physical layer channel or signaling.

[0115] - PDCCH (Physical Downlink Control Channel)

[0116] - DCI (Downlink Control Information)

[0117] - Terminal-specific (UE-specific) DCI

[0118] - Group common DCI

[0119] - Common DCI

[0120] - Scheduling DCI (e.g., DCI used for the purpose of scheduling downlink or uplink data)

[0121] - Non-scheduling DCI (e.g., DCI not intended for scheduling downlink or uplink data)

[0122] PUCCH (Physical Uplink Control Channel)

[0123] - UCI (Uplink Control Information)

[0124] The term "slot" used in the present disclosure below is a general term that may refer to a specific time unit corresponding to TTI (Transmit Time Interval), and specifically, it may mean a slot used in a 5G system, or a slot or subframe used in a 4G LTE system.

[0125] As explained earlier regarding antenna switching, since reciprocity exists between the uplink and downlink channels in a TDD system, if channel information for one of the two channels can be obtained, information for the other channel can also be estimated. Because base stations consist of a larger number of transmitting antennas than terminals, estimating the downlink channel between the base station and the terminal requires the base station to transmit a greater number of reference signal ports to the terminal compared to estimating the uplink channel. This means that to orthogonally estimate the downlink channel between each transmitting antenna port of the base station and all terminal antenna ports, a number of CSI-RS (channel state information - reference signals) equal to the number of base station transmitting antennas may be required. On the other hand, to estimate the downlink channel based on reciprocity with the uplink channel, the terminal only needs to transmit a number of SRS (sounding reference signals) equal to the number of terminal receiving antennas to the base station.

[0126] FIG. 2 is an example comparing a method for estimating a downlink channel based on a channel state information-reference signal (CSI-RS) and a method for estimating a downlink channel based on SRS and reciprocity in a wireless communication system according to one embodiment of the present disclosure.

[0127] Referring to FIG. 2, it can be assumed that a terminal (200) receives a downlink channel with two receiving antennas and a base station (210) transmits a downlink channel with four transmitting antennas. If the base station (210) transmits CSI-RS (221, 222, 223, 224) for each transmitting antenna port to the terminal (200), the terminal (200) can measure the downlink channel. Subsequently, the terminal (200) can report the channel state information (hereinafter CSI) of the downlink channel estimated from the received CSI-RS (221, 222, 223, 224) to the base station (210). On the other hand, if the terminal (200) transmits SRS (231, 232) for each receiving antenna port to the base station (210), the base station (410) can measure the uplink channel. In this way, if a base station measures the uplink channel based on SRS and estimates the downlink channel through this, the base station can obtain downlink channel information without quantization errors caused by CSI feedback. Furthermore, considering the number of antenna ports of the base station and the terminal, there is an advantage in that the base station can estimate the downlink channel using a small number of SRS ports compared to the total number of CSI-RS ports. If a high-performance base station with a very large number of transmitting antenna ports is considered (for example, a base station composed of 32 transmitting antenna ports), the advantages of SRS-based downlink channel estimation can be even greater. On the other hand, because the transmission power of the SRS transmitted by the terminal is very small compared to the transmission power of the CSI-RS transmitted by the base station, it may be difficult for the base station to successfully receive the SRS if the distance between the base station and the terminal is very large or if sufficient uplink coverage is not secured. Alternatively, because the estimation error of the uplink channel becomes very large, the base station may find it difficult to estimate the downlink channel based on the reciprocity of the uplink channel.Despite these disadvantages, if sufficient coverage of the uplink channel between the base station and the terminal can be secured, using a method to acquire SRS-based downlink channel information can enable efficient use of RS resources from a system perspective and acquire the downlink channel without quantization error.

[0128] The terminal can support transmission through m antennas and reception through n antennas, such as 'mTnR'. Considering the complexity and cost of the transmitting antennas, the number of transmitting antennas m of the terminal may be less than or equal to the number of receiving antennas n. If the number of transmitting antennas m and the number of receiving antennas n are the same, a separate antenna switching process for acquiring a downlink channel based on SRS may not be required, as described above. This can be understood as meaning that an RF chain for uplink transmission is implemented on all receiving antennas. On the other hand, if the number of receiving antennas n is greater than the number of transmitting antennas m, an antenna switching process may be required to transmit SRS through all n receiving antennas, as described above. For example, if the terminal is implemented with 2 transmitting antennas and 4 receiving antennas, the terminal needs to be implemented so that the SRS signal is transmitted through a total of 4 antennas by switching the 2 transmitting antennas once each to transmit SRS for downlink channel estimation to the 4 receiving antennas.

[0129] Considering the cost and complexity of the terminal, the number of transmitting antennas may be smaller than the number of receiving antennas. For example, receiving modules such as receiving filters are connected to all receiving antenna parts of the terminal, so that downlink signals can be received by n receiving antennas. On the other hand, transmitting RF chain modules such as transmitting filters, as well as LNAs (low noise amplifiers) and PAs (power amplifiers), are connected to only some of the transmitting antenna parts of the total antennas, so that uplink signals can be transmitted by only m transmitting antennas. The above-described implementation method may be one that takes into account the heat generation, cost, and interference between components of the terminal. When the terminal supports mTnR and m is smaller than n, the terminal can perform antenna switching to acquire a downlink channel based on SRS as described above.

[0130] FIG. 3 illustrates an example of a case in which, in a wireless communication system according to one embodiment of the present disclosure, when a terminal supports 1T4R, the terminal performs SRS antenna switching so that the base station acquires a downlink channel.

[0131] Referring to FIG. 3, a terminal can perform uplink transmission based on a single transmitting antenna port using a single transmitting module (e.g., LPAF. The LPAF may be composed of an LNA, a PA, and a filter) (300). If the terminal performs antenna switching for four receiving antennas (301, 302, 303, 304), the terminal can transmit SRS by sequentially switching the single transmitting module (300) from the first antenna (301) to the fourth antenna (304) using a switch (305). At this time, due to path loss caused by the form factor of the terminal and the placement location of the receiving antennas, the terminal may transmit SRS at a power lower than the power applied by the transmitting module. Transmitting SRS at a power lower than the power applied by the transmitting module can be defined as insertion loss (IL). In addition, the terminal may intentionally lower the target power level to prevent interference or interference, depending on the operation of other components of the terminal (e.g., camera, Bluetooth, Wi-Fi, etc., or other RF components), as well as reasons such as terminal shape and path loss. For example, when performing SRS antenna switching, an imbalance may occur in the SRS transmission power (311, 312, 313, 314) transmitted by each antenna due to insertion loss as well as interactions between other components of the terminal. As shown in the example illustrated in FIG. 3, the magnitude of the SRS transmission power (312 to 314) transmitted to the second to fourth antennas may be relatively smaller than the SRS transmission power (311) transmitted to the first antenna.The relative smaller magnitude of the SRS transmission power transmitted to the second through fourth antennas compared to the SRS transmission power transmitted to the first antenna can be defined as insertion loss imbalance (IL imbalance). For example, due to the terminal's transmitting module, antenna placement, and interactions between other factors, a problem may arise where the SRS transmitted to each receiving antenna cannot be delivered with uniform transmission power.

[0132] FIG. 4 is a diagram showing an example of a terminal structure supporting four receiving antennas in a wireless communication system according to one embodiment of the present disclosure.

[0133] Referring to FIG. 4, unlike FIG. 3, an example of a terminal supporting four receiving antennas (401 to 404) can be illustrated. Unlike the transmitting module, the receiving module (DRX-M, diversity Rx module) (411 to 414) for diversity support can be implemented with a simpler structure and is therefore cheaper than the transmitting module, so it can be deployed and operated on all receiving antennas. Therefore, since there may not be a significant difference in the amount of insertion loss between each receiving antenna (401 to 404) and the receiving module (411 to 414), unlike the case described above (e.g., FIG. 3), the power imbalance between downlink channels or downlink reference signals, such as CSI-RS, received by each antenna may be very small or non-existent.

[0134] In addition to power imbalance (or power imbalance) caused by Tx-Rx mismatch resulting from the difference between the transmitter RF structure and the receiver RF structure of the terminal described above, the difference in transmission power between SRS resources for antenna switching purposes may be greater due to other terminal implementation elements, as illustrated in FIG. 3. For example, elements for non-communication functions, such as a camera, may be implemented in adjacent parts between a specific antenna path (e.g., the second antenna (302) in FIG. 3) and the RF transmitter module (300). If power for uplink transmission is applied to an adjacent transmitter RF path, RF interference may occur, which may adversely affect the image quality or operation of the camera. For this reason, if a module such as a camera is turned on (or is in an 'on' state), the terminal may intentionally reduce the amount of power applied to the antenna adjacent to the module such as a camera. For example, the transmission power of uplink signals transmitted to some antennas may be intentionally reduced by considering not only the mismatch between the transmitter and receiver due to the RF structure of the terminal but also the impact on modules of other terminals. As a result, multiple SRS resources intended for antenna switching, which should be transmitted at the same transmission power, may be transmitted at different transmission powers.

[0135] As shown in Figures 3 and 4, depending on the occurrence of IL imbalance, a difference may arise between the downlink channel estimated based on the SRS transmitted by the terminal and the downlink channel received by the terminal. For example, the base station ideally expects that the downlink channel received by the terminal and the downlink channel obtained through SRS antenna switching are identical; however, due to the occurrence of IL imbalance, an estimation error may occur between the actual downlink channel received by the terminal and the downlink channel estimated by the base station through SRS antenna switching. If the accuracy of the downlink channel estimated by the base station through SRS antenna switching can be improved, the base station can perform accurate precoding on the downlink channel transmitted to the terminal, and through accurate precoding, beamforming gain can be maximized to increase downlink throughput.

[0136] <1st Embodiment: Method for measuring and reporting DL RS RSRP per antenna>

[0137] In the first embodiment, to improve the accuracy of a DL channel estimated by an SRS that is not transmitted with uniform power due to IL imbalance of a terminal that cannot be identified by the base station, a method of transmitting a DL RS to the terminal and the terminal measuring a CSI (channel state information) to compensate for the degradation of channel estimation accuracy caused by power imbalance is specifically described in the 1-1 embodiment, and a method of the terminal reporting the measured CSI to the base station is specifically described in the 1-2 embodiment.

[0138] <1-1 Embodiment: Method for Measuring DL RS RSRP by Antenna>

[0139] In the 1-1 embodiment, a method is specifically described in which a terminal receives a DL RS, measures and reports the RSRP (reference signal received power) for each terminal antenna, and a base station estimates power imbalance information based on this.

[0140] The terminal can receive a DL RS (Downlink Reference Signal) based on RRC parameters set by the base station and the received scheduling DCI, and measure the CSI using the received DL RS. Subsequently, the terminal can report the CSI to the base station based on RRC parameters set by the base station and the received scheduling DCI.

[0141] A terminal can use an SSB (SS / PBCH block, synchronization signal / physical broadcast channel block) or a CSI-RS (channel state information reference signal) as a DL RS capable of receiving to measure CSI. Hereinafter, DL RS may refer to an SSB or a CSI-RS or both an SSB and a CSI-RS.

[0142] If a terminal receives DL RS, it receives the DL RS transmitted to each port of the base station through the receiving antennas of all terminals. For example, if the base station transmits 16 ports of CSI-RS, the base station may transmit each CSI-RS port orthogonally in the time, frequency, or code domain. If the terminal receives CSI-RS using 4 antenna ports, the terminal receives each CSI-RS port and can estimate a 4x1 channel (or the dimension can be transformed to 1x4, but there is no change in the channel estimate value). Finally, since the terminal receives 16 CSI-RS ports through 4 receiving antenna ports, it can estimate a DL channel of size 4x16 (or 16x4). Subsequently, the terminal can calculate PMI, CQI, RI, etc., based on the reportQuantity within the configuration for the CSI report (CSI-ReportConfig) associated with the corresponding CSI-RS set by the terminal's implementation and the base station, configure this into a CSI, and report it to the base station. In this way, when the terminal receives DL RS such as CSI-RS, it can calculate channel information using all of the terminal's receiving antennas and report it to the base station. If the terminal measures the RSRP (CSI-RSRP) for CSI-RS and reports it to the base station, the terminal can calculate the CSI-RSRP using the CSI-RS transmitted to antenna port 3000. If the terminal calculates the CSI-RSRP as L1-RSRP, the terminal can calculate the CSI-RSRP for L1-RSRP using the CSI-RS transmitted to antenna ports 3000 and 3001. In this case, the terminal can receive the CSI-RS transmitted to the designated antenna port using all of the terminal's receiving antennas and calculate a single CSI-RSRP value for the corresponding CSI-RS.

[0143] FIG. 5 shows an example of a case in which a terminal receives CSI-RS from a base station and calculates CSI-RSRP in a wireless communication system according to one embodiment of the present disclosure.

[0144] Referring to FIG. 5, a base station (510) can transmit CSI (520) to a terminal (500). For convenience of explanation, it is assumed that the base station (510) is composed of four transmitting and receiving antennas (511, 512, 513, 514) and the terminal (500) is composed of two receiving antennas (501, 502), but base stations and terminals composed of four or more transmitting and receiving antennas can be considered. If the base station schedules a CSI report to report CSI-RSRP to the terminal, the terminal can measure and report CSI-RSRP using the CSI reference signal transmitted by the base station to antenna port 3000. Or, if the terminal reports CSI-RSRP using L1-RSRP, the terminal can measure and report CSI-RSRP using L1-RSRP using the CSI reference signal transmitted by the base station to antenna ports 3000 and 3001. If the antenna port 3000 of the base station (510) can be assumed to be the first antenna (511) among the transmitting antennas of the base station (510) of FIG. 5, the base station (510) can use the first antenna (511) to transmit a CSI reference signal (520) to the terminal (500), and the terminal (500) can receive this through the receiving antennas (501, 502) of all terminals to measure the CSI-RSRP and report it to the base station (510). FIG. 5 is merely one example, and similarly for a base station having a number of antennas greater than or less than four and a terminal having a number of antennas greater than or less than two, the base station can transmit a CSI reference signal to the terminal, and the terminal can receive the CSI reference signal transmitted by the base station and report the CSI-RSRP to the base station.Here, if the terminal measures RSRP rather than L1-RSRP using CSI-RSRP, the base station transmits a CSI reference signal to one antenna port (e.g., base station antenna port 3000), and the terminal receives the CSI reference signal transmitted by the base station through two or more than two terminal antenna ports to calculate the CSI-RSRP and report it to the base station. Alternatively, if the terminal measures L1-RSRP using CSI-RSRP, the base station transmits a CSI reference signal to two antenna ports (e.g., base station antenna port 3000 and antenna port 3001), and the terminal receives the CSI reference signal transmitted by the base station through two or more than two terminal antenna ports to calculate the L1-RSRP and report it to the base station.

[0145] In a TDD system, since the base station cannot know the power imbalance that may be included in the SRS (i.e., SRS antenna switching) transmitted by the terminal for the purpose of estimating the downlink (DL) channel, the base station receives SRS resources that are not transmitted with equal power and estimates the uplink (UL) and DL channels based on this. To obtain additional information about SRS resources transmitted with unequal power, the base station can transmit a DL reference signal (RS) to the terminal and instruct (or schedule) the terminal to report information regarding RSRP or channel quality for each terminal's antenna port. This means that if the base station compares the received signal strength of the SRS resources transmitted by the terminal to each antenna port with the received signal strength of the CSI-RS received by the terminal to each antenna, the base station can indirectly infer the power imbalance included when the terminal transmits the SRS resources. At this time, a prerequisite is required that the antenna port of the terminal transmitting SRS antenna switching and the antenna port of the terminal receiving CSI-RS have the same QCL (Quasi Co-Located) assumption. In particular, in any frequency band where FR2 or an analog beam is operated, the antenna port of the terminal transmitting SRS antenna switching and the antenna port receiving CSI-RS may have the same QCL type D, or the transmitting analog beam of the antenna port of the terminal transmitting SRS antenna switching and the receiving analog beam of the antenna port receiving CSI-RS may be the same.

[0146] FIG. 6 illustrates an example of a case in which a terminal performs 1T2R SRS antenna switching using each antenna in a wireless communication system according to one embodiment of the present disclosure.

[0147] It is assumed that the terminal (600) has two antennas (601, 602) and uses both antennas (601, 602) when receiving DL, and when transmitting UL, the terminal has only one RF chain so that only 1Tx transmission is possible. It is assumed that the base station (610) has four antennas (611, 612, 613, 614) and can use all four antennas (611, 612, 613, 614) when transmitting DL and receiving UL.

[0148] If the base station (610) triggers an SRS resource set for antenna switching to the terminal (600), for example, the terminal (600) can transmit SRS resource 1 (603), which is the first SRS resource of the SRS resource set for antenna switching triggered to the base station (610), using the first antenna (601). The base station (610) can receive SRS resource 1 (603) transmitted by the terminal (600) using all four antennas (611, 612, 613, 614). Subsequently, the terminal (600) can transmit SRS resource 2 (604), which is the second SRS resource of the SRS resource set for antenna switching triggered to the base station (610), using the second antenna (602). The base station (610) can receive SRS resource 2 (604) transmitted by the terminal (600) using all four antennas (611, 612, 613, 614). At this time, the terminal (600) can transmit the two SRS resources (603, 604) through different time resources (TDM).

[0149] As described above, depending on the implementation of the terminal, the actual transmission power of the two SRS resources (603, 604) transmitted to the two antennas (601, 602) may differ due to insertion loss and imbalances caused by interactions between other components. For example, the terminal is scheduled to transmit the two SRS resources (603, 604) at 23 dBm each, but due to power imbalances in the transmission antennas, SRS resource 1 (603) may be transmitted at 23 dBm through the first antenna (601), while SRS resource 1 (604) may be transmitted at 20 dBm instead of 23 dBm through the second antenna (602). The base station (610) can receive SRS resource 1 (603) transmitted by the terminal (600) at 23 dBm using some base station antennas (e.g., all base station antennas or some antennas) at an RSRP of about 13 dBm, and can receive SRS resource 2 (604) transmitted by the terminal (600) at 20 dBm at an RSRP of about 8 dBm using some base station antennas (e.g., all base station antennas or some antennas) after experiencing path loss and fading similar to that of SRS resource 1 (603). At this time, the difference between the RSRP of SRS resource 1 (603) received by the base station (610), which is 13 dBm, and the RSRP of SRS resource 2 (604), which is 8 dBm, may occur in the form of an additional 2 dB loss due to channel and fading and a 3 dB loss due to power imbalance. The base station (610) can calculate 5 dB through the difference in received RSRP between the two SRS resources (603, 604), but it cannot distinguish between the value due to power imbalance in the calculated 5 dB and the additional loss value due to channel and fading between the base station (610) and the other antenna (601, 602) of the terminal (600).Therefore, the accuracy of channel estimation may be reduced because the actual channel and the UL channel due to fading cannot be accurately estimated, and a channel with power imbalance is estimated instead.

[0150] FIG. 7 illustrates an example of a case in which a terminal receives CSI-RS transmitted by a base station to two antenna ports in a wireless communication system according to one embodiment of the present disclosure, measures RSRP, and reports it at each antenna port.

[0151] In FIG. 7, the terminal (700) has two antennas (701, 702) as in FIG. 6, and it is assumed that both antennas (701, 702) are available for use when receiving DL. The base station (710) has four antennas (711, 712, 713, 714), and it is assumed that all four antennas (711, 712, 713, 714) are available for use when transmitting DL.

[0152] The base station (710) can transmit the first CSI-RS resource 1 (715) to the terminal (700) using the first antenna port (711). Here, the first antenna port (711) of the base station (710) refers to a logical port and may also refer to transmission through multiple or single physical RF chains. For convenience of explanation, the description is based on the logical antenna port, and this logical first antenna port refers to the first CSI-RS antenna port 3000. The terminal (700) can receive the CSI-RS resource 1 (715) transmitted by the base station (710) to the first antenna port (711) using all of the terminal's antenna ports (701, 702) and calculate the RSRP. The base station (710) can transmit a second CSI-RS resource 2 (716) to the terminal (700) using the second antenna port (712). The terminal (700) can receive the CSI-RS resource 2 (716) transmitted by the base station (710) to the second antenna port (712) using all of the terminal's antenna ports (710, 702) and calculate the RSRP. At this time, the base station (710) can transmit the two CSI-RS resources (715, 716) to different time resources (TDM), to different frequency resources (FDM), or to different OCC (orthogonal cover code) (CDM). It can be assumed that the base station (710) can transmit the CSI-RS resource with the same power using each antenna port. For example, it can be assumed that the base station (710) transmits both the first CSI-RS resource 1 (715) and the second CSI-RS resource 2 (716) at 40 dBm.The terminal (700) can receive CSI-RS resource 1 (715) with an RSRP of about 35 dBm using two antennas (701, 702), and similarly, can receive CSI-RS resource 2 (716) with an RSRP of about 34 dBm using two antennas (701, 702). The terminal can report either RSRP (e.g., the average of the two RSRPs measured by the two CSI-RS resources (715, 716)) to the base station using the RSRPs measured by the two CSI-RS resources (715, 716).

[0153] If a terminal can receive a CSI-RS resource transmitted by a base station through each terminal's antenna and measure the RSRP for each antenna, and report the RSRP measured by each antenna to the base station, the base station can determine the RSRP of the CSI-RS resource received by each terminal antenna reported by the terminal, and can estimate the power imbalance included when the terminal transmits SRS using the RSRP value for each antenna for the CSI-RS resource reported by the terminal and the RSRP value for each SRS resource received by the base station. More specifically, using FIG. 7, the terminal (700) can receive CSI-RS resource 1 (715) transmitted by the base station (710) with an RSRP of 36 dBm using the terminal's first antenna (701). Additionally, the terminal (700) can receive CSI-RS resource 1 (715) with an RSRP of 34 dBm using the terminal's second antenna (702).

[0154] As described above, the RSRP of CSI-RS resource 1 received by two antennas can be determined to be 35 dBm, which is the average of 36 dBm and 34 dBm, but the RSRP of CSI-RS resource 1 received by each antenna may be different values ​​due to effects such as fading. If the terminal can report the RSRP measured by each antenna rather than the average value of the RSRP of the CSI-RS resource 1 (715) received by the two antennas, the base station (710) can determine that the terminal (700) received the CSI-RS resource 1 (715) with an RSRP of 36 dBm using the first antenna (701 or 601 of FIG. 6) of the terminal that transmitted the first SRS resource 1 (603) of FIG. 6, and can determine that the terminal received the CSI-RS resource 1 (71) with an RSRP of 36 dBm using the second antenna (702 or 602) of the terminal that transmitted the second SRS resource 2 (604) of FIG. 6. In this case, the terminal antenna that received the RSRP reported by the terminal and the terminal antenna that the terminal used to transmit the SRS resource must be the same. In other words, the base station and the terminal must be defined so that the antenna transmitting the SRS resource for antenna switching purposes is the same as the antenna receiving the CSI-RS resource transmitted by the base station and measuring the RSRP. The specific method for defining the terminal's antenna will be explained below.

[0155] In this way, the base station can infer the difference in RSRP due to the channel and the difference in RSRP due to power imbalance included when the terminal transmits SRS, by using the difference in RSRP between the received SRS resources in Fig. 6 and the RSRP information of the CSI-RS resource received by each antenna reported by the terminal. By referring to the RSRP per antenna reported by the terminal, the base station can determine that an additional loss of 2 dB may occur when receiving a DL RS or DL ​​channel with the second antenna compared to the first antenna due to fading and other factors between the channel between the base station and each antenna of the terminal, through the difference between the RSRP of 36 dBm when CSI-RS resource 1 is received by the terminal's first antenna and the RSRP of 34 dBm when CSI-RS resource 1 is received by the terminal's second antenna. Additionally, as explained in FIG. 6, it can be inferred that 2 dB of the 5 dB calculated through the two SRS resources (603, 604) is an additional loss due to the difference in channels between the base station and the antenna, and 3 dB is an error value caused by the power imbalance that occurs when the terminal transmits the two SRS resources to different antennas. The above-described example can be illustrated as in FIG. 8.

[0156] FIG. 8 illustrates a process for inferring power imbalance that occurs when a terminal transmits SRS resources using RSRP values ​​for each antenna of the terminal reported by the terminal in a wireless communication system according to one embodiment of the present disclosure, and RSRP values ​​of SRS resources measured by a base station and RSRP values ​​of the terminal reported by the terminal.

[0157] Referring to FIG. 8, a terminal (800) transmits SRS resource 1 (803) and SRS resource 2 (804) to a base station (810). The base station (810) can receive the two SRS resources (803, 804) with four antennas (811, 812, 813, 814) and can measure the RSRP of the two SRS resources (803, 804) received through the first antenna (811). For example, the RSRP of SRS resource 1 (803) received by the first antenna (811) of the base station (800) is 10 dBm, and the RSRP of SRS resource 2 (804) received by the first antenna (811) is also 10 dBm. The base station (810) can transmit CSI-RS resource 1 (815) to the terminal (800) using the base station's first antenna (811). The terminal (800) can receive CSI-RS resource 1 (815) with two antennas (801, 802), and the RSRP of CSI-RS resource 1 (815) received through the first antenna (801) may be 36 dBm, and the RSRP of CSI-RS resource 1 (815) received through the second antenna (802) may be 34 dBm. The terminal can report the two RSRP values ​​for CSI-RS resource 1 (815) measured using the two antennas (801, 802) to the base station.

[0158] The base station (810) receives two RSRP values ​​for CSI-RS resource 1 (815) reported by the terminal (800) and can determine that the difference in channel strength between the terminal's two antennas (801, 802) is 2 dB through the difference between 36 dBm and 34 dBm. The base station can also determine that among the RSRP values ​​of the two SRS resource 1 (803) and SRS resource 2 (804) transmitted by the terminal, the power loss of SRS resource 2 (804) is 2 dB greater than the power loss of SRS resource 1 (803) through the difference between the two RSRP values ​​reported by the terminal for CSI-RS resource 1 (815). That is, the received RSRP of the first SRS resource 1 (803) can be determined to be 10 dBm, with power loss L1 occurring in the transmission power P1 of SRS resource 1, and the received RSRP of the second SRS resource 2 (804) can be determined to be 10 dBm, with power loss L1+2 occurring in the transmission power P2 of SRS resource 2. Therefore, assuming L1 is the same, it can be seen that P1 is 2 dBm smaller than P2 (P1 - L1 = 10 dBm, P2 - L1 - 2 = 10 dBm). If the base station transmitted CSI-RS resource 1 (815) at 40 dBm, it can be seen that L1 is 4 dB, and the base station can deduce that the terminal used about 14 dBm to transmit SRS resource 1 and about 16 dBm to transmit SRS resource 2. Therefore, the base station can infer that when the terminal transmits SRS resource 1 (803) using the first antenna (801) compared to when it transmits SRS resource 2 (804) using the second antenna (802), a power imbalance (loss) of 2 dB occurs.Therefore, the base station can correct the UL channel estimated by the two SRS resources (803, 804) by taking into account the inferred 2 dB power imbalance.

[0159] In order to use the method described through the specific example in Fig. 8, a prerequisite is required that the antenna port of the terminal transmitting SRS antenna switching and the antenna port of the terminal receiving CSI-RS have the same QCL assumption as described above. Furthermore, the RSRP in the example described above may refer to both L3-RSRP calculated based on upper layer filtering and L1-RSRP calculated based on physical layer filtering. If it refers to L1-RSRP, the terminal can measure the L1-RSRP of the CSI-RS resources received by each antenna by additionally using CSI-RS resource 2, which can be transmitted to the base station's second antenna (812 or 712), in addition to CSI-RS resource 1 in the example described above.

[0160] <Embodiment 1-2: Method for Reporting DL RS RSRP by Antenna>

[0161] In the first-2nd embodiment, a method for a base station to schedule SRS antenna switching, CSI-RS transmission, and CSI reporting as in the first-1st embodiment is explained, and a method for a terminal to report RSRP per terminal antenna to the base station is explained in detail.

[0162] The base station may transmit a CSI-RS resource and schedule the reporting of RSRPs per terminal antenna to identify power imbalance information regarding SRS antenna switching transmitted by the terminal. In this case, the CSI-RS resource and the CSI report for reporting RSRPs per terminal antenna may be associated with SRS antenna switching, and this association may be explicitly established or implicitly understood.

[0163] The terminal can perform SRS antenna switching as described above and can support additional terminal capabilities to receive CSI-RS resources that may be explicitly or implicitly associated with SRS antenna switching and to report terminal antenna-specific RSRPs as CSIs. The terminal can report to the base station additional terminal capabilities (e.g., 'additionalCSIforSRSAS', etc.) that may receive CSI-RS resources associated with SRS antenna switching and to report terminal antenna-specific RSRPs as CSIs. If the base station receives additional terminal capabilities (e.g., 'additionalCSIforSRSAS', etc.) from the terminal, it may set upper-layer parameters (RRC parameters) to the terminal as follows, and the terminal can perform CSI-RS resource reception associated with SRS antenna switching and CSI reporting through the set RRC parameters.

[0164] The base station can set RRC parameters for receiving CSI-RS resources and reporting CSI associated with SRS antenna switching in the terminal through one or more RRC parameter setting methods as follows:

[0165] - The base station may set NZP-CSI-RS-ResourceId to set a CSI-RS resource associated with SRS antenna switching in an RRC parameter (SRS-ResourceSet) for an SRS resource set for antenna switching (usage set to 'antennaSwitching'), or set NZP-CSI-RS-ResourceSetId to set an NZP-CSI-RS-ResourceSet containing the associated CSI-RS resource, or set CSI-ResourceConfigId to set a CSI-ResourceConfig containing the associated CSI-RS resource.

[0166] - A base station may set the SRS-ResourceSetId of an associated SRS resource set within NZP-CSI-RS-ResourceSet or the SRS-ResourceSetId of an associated SRS resource set within NZP-CSI-RS-Resource to set a CSI-RS resource associated with an SRS resource set for antenna switching purposes (where usage is set to 'antennaSwitching'). Alternatively, the base station may set the SRS-ResourceSetId of an associated SRS resource set within a CSI-ResourceConfig containing a CSI-RS resource associated with an SRS AS.

[0167] - The base station may set CSI-ReportConfigId in the RRC parameter (SRS-ResourceSet) for an SRS resource set intended for antenna switching (where usage is set to 'antennaSwitching') to configure a CSI report that includes RSRP per terminal antenna measured by a CSI-RS resource associated with SRS antenna switching. For the CSI-ReportConfig configured for a CSI report that includes RSRP per terminal antenna measured by a CSI-RS resource associated with SRS antenna switching, a parameter to indicate a new type of CSI report can be set as reportQuantity, as described below.

[0168] - When reporting RSRP per terminal antenna based on L3-RSRP, a single CSI port (e.g., nrofPorts set to p1) can be configured in the CSI-RS-ResourceMapping within NZP-CSI-RS-Resource that contains the CSI-RS resource associated with SRS antenna switching.

[0169] - When reporting RSRP per terminal antenna based on L1-RSRP, the CSI-RS-ResourceMapping within NZP-CSI-RS-Resource, which contains the CSI-RS resource associated with SRS antenna switching, can be configured with multiple CSI ports (e.g., nrofPorts can be set to p2, or a number of ports greater than p2 can be supported).

[0170] - A new type of report information can be set as the reportQuantity of CSI-ReportConfig to set up CSI reporting that includes RSRP per terminal antenna measured by a CSI-RS resource associated with SRS antenna switching. For example, a base station can define and set a new type that can report RSRP per antenna, such as CSI-RSRPB, CSI-RSRPperPort, or cri-RSRP-perAntenna, as the reportQuantity of CSI-ReportConfig.

[0171] Among the RRC parameter settings described above, the new type of reporting information configured in CSI-ReportConfig may be mandatory, while other parameters may be optional. In other words, through the RRC parameter settings described above, CSI reporting for reporting RSRPs for CSI-RS resources and terminal antennas can be explicitly associated with SRS antenna switching. If no RRC parameters are configured on the terminal, excluding the RRC parameter for configuring the new type of reporting information in CSI-ReportConfig, it can be understood that CSI reporting for reporting RSRPs for CSI-RS resources and terminal antennas is implicitly associated with SRS antenna switching.

[0172] Since the CSI reporting for reporting RSRP per terminal antenna and the CSI-RS resource described in this embodiment is a report associated with SRS antenna switching, a method for scheduling the CSI-RS resource and CSI reporting can be defined as follows, depending on the time domain behavior (periodic, semi-persistent, or aperiodic) of the SRS antenna switching.

[0173] - Periodic SRS AS: You can set the RRC parameter so that the period of the Periodic (P) SRS is the same as the period of the CSI-RS resource and CSI reporting associated with the P SRS. Alternatively, you can set the RRC parameter so that the period of the P SRS has a relationship with the period of the CSI-RS resource and CSI reporting associated with the P SRS (e.g., the period of the CSI-RS resource and CSI reporting is a multiple of the P SRS period). Specifically, if the time domain behavior of the SRS-Resources configured in the SRS-ResourceSet for SRS AS is periodic and the period set by periodicityAndOffset-p of the SRS-Resources is set to the same value (e.g., set to 'sl20' for a 20-slot period), the base station can set the CSI-ReportConfig associated with the P SRS AS to periodic and set the RRC parameter (e.g., slots20 and an offset value for CSI-ReportPeriodicityAndOffset) so that the period set by CSI-ReportPeriodicityAndOffset has the same period as the period value for the SRS-Resources (e.g., a 20-slot period). Alternatively, the base station may set the CSI-ReportConfig associated with the P SRS AS to periodic, and the RRC parameter (e.g., slots40 and some value for the offset in CSI-ReportPeriodicityAndOffset) may be set so that the period set in CSI-ReportPeriodicityAndOffset has a period that is a multiple of some period value for SRS-Resources (e.g., 20 slot period).

[0174] Alternatively, the base station may set the CSI-ReportConfig associated with the P SRS AS to semiPersistentOnPUCCH (if the CSI is reported as PUCCH) or semiPersistentOnPUSCH (if the CSI is reported as PUSCH), and the RRC parameter (e.g., any value for slots20 or slots40 and its offset as CSI-ReportPeriodicityAndOffset) may be set so that the period set by CSI-ReportPeriodicityAndOffset has a period that is the same as or a multiple of any period value for SRS-Resources (e.g., 20 slot periods).

[0175] Alternatively, P SRS AS, aperiodic (AP) CSI-RS resource, and AP CSI reporting may be associated. In this case, the base station may schedule the reception of the AP CSI-RS resource and AP CSI reporting to the terminal before or after the transmission of the P SRS AS, as needed.

[0176] Similarly, for the NZP-CSI-RS-Resource associated with the P SRS AS, the RRC parameter can be set so that the period set by CSI-ResourcePeriodicityAndOffset has a period that is equal to or a multiple of any period value for the SRS-Resources. In addition, the time domain behavior of the CSI-ResourceConfig configured for the NZP-CSI-RS-Resource associated with the P SRS AS can be set to any of periodic, semiPersistent, or aperiodic.

[0177] - Semi-persistent SRS AS: RRC parameters can be set so that the period of the Semi-Persistent (SP) SRS is the same as the period of the CSI-RS resource and CSI report associated with the SP SRS. Alternatively, RRC parameters can be set so that the period of the SP SRS and the periods of the CSI-RS resource and CSI report associated with the SP SRS have a specific relationship (e.g., the periods of the CSI-RS resource and CSI report are multiples of the SP SRS period). Furthermore, when the SP SRS is activated via the MAC CE transmitted by the base station, the CSI-RS resource and CSI report associated with the SP SRS can also be activated via the MAC CE. Alternatively, the CSI report associated with the SP SRS (e.g., time domain behavior is semiPersistentOnPUSCH) can be activated via the CSI request field of the DCI scrambled as SP-CSI-RNTI. In this case, specifically, when the time domain behavior of the SRS-Resources set in the SRS-ResourceSet for SRS AS is semi-persistent and the period set by periodicityAndOffset-p of the SRS-Resources is set to the same value (e.g., set to 'sl20' for a 20-slot period), the base station may set the CSI-ReportConfig associated with the SP SRS AS to either semiPersistentOnPUCCH or semiPersistentOnPUSCH, and the RRC parameter (e.g., a value for slots20 and its offset as CSI-ReportPeriodicityAndOffset) may be set so that the period set by CSI-ReportPeriodicityAndOffset has the same period as the period value for the SRS-Resources (e.g., a 20-slot period).Alternatively, the base station may set the CSI-ReportConfig associated with the corresponding SP SRS AS to either semiPersistentOnPUCCH or semiPersistentOnPUSCH, and the RRC parameter (e.g., slots40 and some value for the offset in CSI-ReportPeriodicityAndOffset) may be set so that the period set in CSI-ReportPeriodicityAndOffset has a period that is a multiple of some period value for SRS-Resources (e.g., 20 slot periods).

[0178] Alternatively, the SP SRS AS, AP CSI-RS resource, and AP CSI report may be associated. In this case, the base station may schedule the reception of the AP CSI-RS resource and the AP CSI report to the terminal before or after the transmission of the SP SRS AS, as needed.

[0179] Alternatively, SP SRS AS and P CSI-RS resources and P CSI reports may be associated. In this case, the base station may, as needed, associate the P CSI report that was reported or will be reported with the SP SRS AS at the time closest to the time before or after the transmission of the SP SRS AS.

[0180] Similarly, for the NZP-CSI-RS-Resource associated with the corresponding SP SRS AS, the RRC parameter can be set so that the period set by CSI-ResourcePeriodicityAndOffset has a period that is equal to or a multiple of any period value for the SRS-Resources. In addition, the time domain behavior of the CSI-ResourceConfig configured for the NZP-CSI-RS-Resource associated with the SP SRS AS can be set to any of periodic, semiPersistent, or aperiodic.

[0181] - Aperiodic SRS AS: Aperiodic (AP) SRS can be associated with AP CSI-RS resources and AP CSI reports, and can be triggered through the same DCI. For example, a base station can trigger an AP SRS AS on a terminal through the SRS request field of a DCI, and can simultaneously trigger the reception of an AP CSI-RS resource and an AP CSI report through the CSI request field of the same DCI. Alternatively, the AP CSI-RS resource and AP CSI report associated with the AP SRS may be triggered through a DCI different from the DCI that triggers the AP SRS.

[0182] Alternatively, the AP SRS AS may be associated with the SP CSI-RS resource and the SP CSI report. In this case, the base station may associate the SP CSI report that was reported or will be reported at the time closest to the time before or after the transmission of the AP SRS AS with the SP SRS AS, as needed.

[0183] Alternatively, the AP SRS AS may be associated with the SP CSI-RS resource and the SP CSI report. In this case, the base station may associate the SP CSI report that was reported or will be reported with the AP SRS AS at the time closest to the time before or after the transmission of the AP SRS AS, as needed.

[0184] Alternatively, the AP SRS AS may be associated with the P CSI-RS resource and the P CSI report. In this case, the base station may associate the P CSI report, which was reported or is to be reported at the time closest to the time before or after the transmission of the AP SRS AS, with the AP SRS AS as needed.

[0185] The above-described method allows the base station to utilize the SRS AS transmitted by the terminal and the reported CSI by referencing them, even if there is no explicit correlation between the SRS AS, the CSI-RS resource, and the CSI report. Even in such cases, as described above, the QCL assumption between the SRS AS and the CSI-RS resource must hold, and the terminal can determine whether to assume the QCL of the SRS AS and the CSI-RS resource are identical based on the type of information reported as CSI, such as the reportQuantity of the CSI report.

[0186] When a base station schedules SRS AS transmission, CSI-RS resource reception, and CSI reporting to a terminal according to the various correlations between SRS AS, CSI-RS resources, and CSI reporting described above, the base station must schedule the terminal by appropriately setting each slot offset (or both periodicity and slot offset) so that SRS AS transmission and CSI-RS resource reception do not overlap, SRS AS transmission and CSI reporting do not overlap, and CSI-RS resource reception and CSI reporting do not overlap.

[0187] The terminal can initiate a procedure to schedule a CSI report to the base station by referring to the terminal's current state (state or in the case where a power imbalance occurs when performing the SRS AS) at the time the base station transmits the SRS AS triggered by the base station.

[0188] The terminal may refer to certain rules to determine whether to request the base station to schedule CSI reports. For example, the rule may define whether the difference in transmission power between an SRS resource capable of transmitting at maximum power during SRS AS transmission and an SRS resource transmitting at minimum power due to reduced power caused by insertion loss or other factors is greater than a certain threshold value. In this case, the threshold for the transmission power difference between SRS resources can be set by the base station to the terminal using RRC parameters, etc. Alternatively, the threshold for the transmission power difference between SRS resources may be determined by the terminal implementation and may be determined independently of the RRC parameters set by the base station. Or, the base station and the terminal may define a fixed value according to specifications as the threshold for the transmission power difference between SRS resources.

[0189] If the terminal decides to request the base station to schedule a CSI report according to any of the rules described above, the terminal may transmit a UL channel to the base station. In this case, the UL channel transmitted by the terminal may be defined as any UL channel for transmitting a small number of bits that are transmitted periodically, such as a PUCCH for transmitting an SR. Alternatively, the terminal may transmit information requesting the scheduling of a CSI report to the base station by multiplexing it to the UL channel that can be transmitted fastest from the time the terminal decides to request the base station to schedule a CSI report.

[0190] A base station may receive a request from a terminal to schedule a CSI report. The base station may or may not schedule a CSI report to the terminal, taking into account the state of the base station. If the base station schedules a CSI report to the terminal, the base station may transmit a DL RS associated with the CSI report to the terminal. In this case, the terminal may receive the DL RS associated with the CSI report and report the CSI (in this case, RSRP for each terminal antenna) measured from the received DL RS to the base station. Alternatively, if the base station schedules a CSI report to the terminal, the base station may schedule only the CSI report without transmitting a DL RS associated with the CSI report to the terminal. In this case, the terminal may report the CSI information received from the most recent DL RS associated with the CSI report to the base station.

[0191] The terminal may use the following CSI reporting format to report the RSRP of the terminal Antana described above to the base station through CSI reporting.

[0192] - [Format 1] A terminal can report RSRPs for each SRS resource of an SRS AS to a base station by configuring them into a CSI field. The terminal receives the CSI-RS resource associated with the SRS AS transmitted by the base station at the terminal antenna, measures the RSRP for each antenna that transmitted the SRS resource of the SRS AS, and can configure this into a CSI field. As a specific example, if the terminal supports a 1T4R SRS AS, it transmits four different SRS resources to each of the four different antennas. For example, the terminal can transmit the first SRS resource within the SRS AS to the terminal's first antenna, the second SRS resource to the second antenna, the third SRS resource to the third antenna, and the fourth SRS resource to the fourth antenna. The terminal receives the CSI-RS resource associated with the SRS AS transmitted by the base station through four terminal antennas, configures the RSRP calculated by receiving the CSI-RS resource with the first antenna as the CSI field of the RSRP for the first SRS resource, configures the RSRP calculated by receiving the CSI-RS resource with the second antenna as the CSI field of the RSRP for the second SRS resource, configures the RSRP calculated by receiving the CSI-RS resource with the third antenna as the CSI field of the RSRP for the third SRS resource, and configures the RSRP calculated by receiving the CSI-RS resource with the fourth antenna as the CSI field of the RSRP for the fourth SRS resource. As another example, if the terminal supports 2T4R SRS AS, it transmits two different SRS resources through two different antennas.For example, the terminal may transmit the first SRS resource within the SRS AS to the terminal's first and second antennas, and the second SRS resource within the SRS AS to the third and fourth antennas. The terminal receives the CSI-RS resource associated with the SRS AS transmitted by the base station with the four terminal antennas, constructs the CSI field as the RSRP for the first SRS resource using the RSRP calculated by receiving the CSI-RS resource with the first and second antennas, and constructs the CSI field as the RSRP for the second SRS resource using the RSRP calculated by receiving the CSI-RS resource with the third and fourth antennas. Table 3 below shows an example of [Format 1]. The CSI field for reporting each RSRP may consist of any number of bits (e.g., 7 bits, or any positive integer greater or less than 7 bits).

[0193] CSI rerpot numberCSI fieldsCSI report #nRSRP for first SRS resource which is included in associated SRS resource setRSRP for second SRS resource which is included in associated SRS resource set...RSRP for last SRS resource which is included in associated SRS resource set

[0194] - [Format 2] The terminal can report to the base station by configuring the differential RSRP for each SRS resource of the SRS AS as a CSI field. [Format 2] reports to the base station by configuring the differential RSRP as a CSI field based on the largest RSRP, rather than the RSRP information of [Format 1]. If the CSI field is configured with differential RSRP rather than RSRP, the signal strength received by each antenna can be reported with fewer bits or with higher accuracy using the same number of bits. If the CSI-RS resource is received with the largest RSRP using the antenna associated with the SRS resource, the terminal reports the differential RSRP for that SRS resource as 0. [Table 4] shows an example of [Format 2], and the CSI field for reporting each differential RSRP can be composed of any number of bits (e.g., 7 bits, identical to the CSI field of [Format 1], or 4 bits, or any positive integer greater or smaller than 4 bits).

[0195] CSI rerpot numberCSI fieldsCSI report #nDifferential RSRP for first SRS resource which is included in associated SRS resource setDifferential RSRP for second SRS resource which is included in associated SRS resource set...Differential RSRP for last SRS resource which is included in associated SRS resource set

[0196] - [Format 3] The terminal can report RSRPs for each receiving antenna to the base station by configuring the CSI field. Unlike [Format 1], [Format 3] configures the RSRPs for each terminal antenna, rather than RSRPs for each SRS resource, as CSI fields. In the specific example described in [Format 1], for a 1T4R SRS AS, the number of CSI fields in [Format 1] and [Format 3] may be the same, and the RSRPs reported by the terminal may also be defined as the same value (provided the mapping between the terminal antenna and the SRS resource is identical). However, in the case of a 2T4R SRS AS, while [Format 1] reported RSRPs for two SRS resources, [Format 3] reports RSRPs for four terminal antennas, just as in the case of a 1T4R SRS AS. A terminal antenna can be defined as a terminal antenna port or as the SRS port configured when transmitting the associated SRS AS. Table 5 below shows an example of [Format 3]. The CSI field for reporting each RSRP may consist of any number of bits (e.g., 7 bits or any positive integer greater or smaller than 7 bits).

[0197] CSI rerpot numberCSI fieldsCSI report #nRSRP for first UE antenna port (or RSRP for first SRS port)RSRP for second UE antenna port (or RSRP for second SRS port)...RSRP for last UE antenna port (or RSRP for last SRS port)

[0198] - [Format 4] The terminal may report differential RSRP to the base station by configuring the CSI field for each receiving antenna of the terminal. [Format 4] reports differential RSRP to the base station by configuring the CSI field based on the largest RSRP, rather than the RSRP information of [Format 3]. [Table 6] shows an example of [Format 4], and the CSI field for reporting each differential RSRP may be composed of any number of bits (e.g., 7 bits, identical to the CSI field of [Format 3], or 4 bits, or any positive integer greater or smaller than 4 bits).

[0199] CSI rerpot numberCSI fieldsCSI report #nDifferential RSRP for first UE antenna port (or RSRP for first SRS port)Differential RSRP for second UE antenna port (or RSRP for second SRS port)...Differential RSRP for last UE antenna port (or RSRP for last SRS port)

[0200] <Second Embodiment: Method for Reporting Power Imbalance Information Based on SRS Received Information Reported by a Base Station>

[0201] In the second embodiment, a method is specifically described for a terminal to transmit information regarding the reception strength of an SRS AS received by a base station to a terminal, and for the terminal to calculate a power imbalance value based on this and report it to the base station.

[0202] Unlike the method of the first embodiment, the base station may receive the SRS AS transmitted by the terminal, measure the reception strength (i.e., RSRP) for each SRS resource, and transmit it to the terminal; the terminal may estimate the power imbalance included when transmitting the SRS resource of the SRS AS by comparing the reception strength information for the SRS resource of the SRS AS transmitted by the base station with the reception strength (i.e., RSRP) of the CSI-RS resource transmitted by the base station. The terminal may report the estimated information on the power imbalance that occurred when transmitting the SRS AS to the base station. The signaling between the entire base station and the terminal is as follows:

[0203] Step 1) The base station triggers an SRS for antenna switching purposes at the terminal, and the terminal transmits the triggered SRS resource to the base station.

[0204] Step 2) The base station receives all SRS resources for antenna switching transmitted by the terminal and measures the received strength (RSRP) of the SRS resources with the antenna of the base station that will transmit the CSI-RS resources in the next step.

[0205] Step 3) The base station can transmit the measured RSRP to the terminal. At this time, the base station can transmit RSRP information regarding the SRS AS to the terminal via PDSCH, and the measured RSRP can be transmitted in a new MAC CE format within the PDSCH. The terminal receives the RSRP information regarding the SRS AS from the base station.

[0206] Step 4) The base station transmits the CSI-RS resource associated with the SRS AS to the terminal. The terminal receives the CSI-RS resource associated with the SRS AS transmitted by the base station and measures the RSRP for each terminal antenna.

[0207] Step 5) The terminal can estimate the power imbalance that occurs when the terminal transmits the SRS resources of the SRS AS by comparing the RSRP per antenna measured by the received CSI-RS resource with the RSRP per SRS resource information for the SRS AS transmitted to the terminal by the base station.

[0208] Step 6) The terminal can report estimated power imbalance information to the base station, and the base station can improve the accuracy of the estimated UL channel using the power imbalance information reported by the terminal.

[0209] FIG. 9 is an example for explaining the process of a terminal estimating power imbalance for SRS AS through the process of Step 1 to Step 6 in a wireless communication system according to one embodiment of the present disclosure.

[0210] Referring to FIG. 9, the terminal (900) transmits two SRS resources (903, 904) to the base station to perform 1T2R antenna switching. The terminal (900) can transmit the first SRS resource 1 (903) to the terminal's first antenna (901) with a transmission power of 20 - A dBm and the second SRS resource 2 (904) to the terminal's second antenna (902) with a transmission power of 20 - B dBm. Here, A represents the final power loss value that occurs when the terminal (900) transmits the SRS to the first antenna (901), and B represents the final power loss value that occurs when the terminal transmits the SRS to the second antenna (902).

[0211] The base station (910) receives two SRS resources (903, 904) transmitted by the terminal (900) and can measure the received RSRP of the SRS with the base station's first antenna (911). The base station (910) receives the first SRS resource 1 (903) at 10 dBm with the first antenna (911) and can receive the second SRS resource 2 (904) at 10 dBm with the same first antenna. The base station (910) can transmit the RSRP of 10 dBm for the first SRS resource 1 (903) and the RSRP of 10 dBm for the second SRS resource 2 (904) to the terminal using a DL channel (e.g., a PDSCH including MAC CE). Here, the received RSRP of the base station (910) for the first SRS resource (903) can be expressed as 20 - A - L1 = 10 dBm, where L1 represents the loss value due to the channel between the terminal's first antenna (901) and the base station's first antenna (911). The received RSRP of the base station (910) for the second SRS resource (904) can be expressed as 20 - B - L2 = 10 dBm, where L2 represents the loss value due to the channel between the terminal's second antenna (901) and the base station's first antenna (911).

[0212] Subsequently, the terminal (900) can receive CSI-RS resource 1 (915) associated with the SRS AS transmitted by the base station (910) through the terminal's two antennas (901, 902). The terminal (900) receives CSI-RS resource 1 (915) at 36 dBm with the first terminal antenna (901) and can receive the same CSI-RS resource 1 (915) at 34 dBm with the second terminal antenna (902). If the terminal (900) does not know the transmission power of the CSI-RS resource 1 (915) transmitted by the base station (910), the terminal can determine that the RSRP of the CSI-RS resource 1 (915) received by the first terminal antenna (901) is X - L1 = 36 dBm and that the RSRP of the CSI-RS resource 1 received by the second terminal antenna (902) is X - L2 = 34 dBm. Here, X represents the transmission power used by the base station (910) to transmit the CSI-RS resource 1 (915).

[0213] The terminal (900) can estimate, using RSRP information (20 - A - L1 = 10 dBm, 20 - B - L2 = 10 dBm) for two SRS resources (903, 904) transmitted by the base station (910) and RSRP values ​​(X - L1 = 36 dBm, X - L2 = 34 dBm) for CSI-RS resource 1 (915) measured by the terminal's two terminal antennas (901, 902), that is, A = B + 2, that is, the final power loss value A that occurs when the terminal transmits SRS resource 1 (903) to the first antenna (901) is 2 greater than the final power loss value B that occurs when the terminal transmits SRS resource 2 (904) to the second antenna (902). That is, the terminal (900) can estimate that when transmitting two SRS resources for SRS AS, there is an additional loss of 2 dB in the first antenna because the power loss when transmitting SRS to the first antenna (901) is 2 dB greater than the power loss when transmitting SRS to the second antenna (902). The terminal (900) can report the estimated power imbalance information to the base station (910). The base station (910) can refer to the power imbalance information reported by the terminal (900) to calibrate the UL channel estimated for the two SRS resources (903, 904) transmitted for SRS AS to improve the channel estimation accuracy, and based on this, estimate the DL channel to perform DL precoding.

[0214] FIG. 10 illustrates an example of a MAC CE format for transmitting the reception strength of each SRS resource received by a base station to a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0215] Referring to FIG. 10, in one embodiment, a MAC CE capable of reporting three different types of reception strength information may be considered. The base station may configure a field (1001) to indicate the cell ID that received the corresponding SRS resource set, and may configure a field (1002) to indicate the ID of the BWP in which the corresponding SRS resource set is set. An SRS resource set ID field (1003) may be configured to indicate which SRS resource within which SRS resource set the reception strength transmitted to the MAC CE was measured. Subsequently, the base station may configure a field (1004) to report the result of receiving each SRS resource of the SRS resource set for antenna switching of the BWP of the corresponding serving cell and measuring the reception strength therefor. The field (1004) for reporting the results of measuring reception strength may be defined as many times as the total number of SRS resources N included in the corresponding SRS resource set, and may report the RSRP for each SRS resource by representing it in 7 bits, report the differential RSRP based on the RSRP measured as the largest value for each SRS resource by representing it in 7 bits, or report the differential RSRP based on the RSRP measured as the largest value for each SRS resource by representing it in 4 bits. In addition to the examples of the field (1004) for reporting reception strength described above, other forms of reception strength may be reported with a different number of bits.

[0216] FIG. 11 is a drawing illustrating the structure of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0217] Referring to FIG. 11, the terminal may include a transceiver (referring to a terminal receiver (1100) and a terminal transmitter (1110), a memory (not shown), and a terminal processing unit (1105, or a terminal control unit or processor). According to the communication method of the terminal described above, the transceiver (1100, 1110), memory, and terminal processing unit (1105) 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 components or fewer components than the components described above. Furthermore, the transceiver (1100, 1110), memory, and processor (1105) may be implemented in the form of a single chip.

[0218] The transceiver (1100, 1110) can transmit and receive signals with a base station. Here, the signal may include control information and data. To this end, the transceiver (1100, 1110) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver (1100, 1110), and the components of the transceiver (1100, 1110) are not limited to an RF transmitter and an RF receiver.

[0219] Additionally, the transceiver (1100, 1110) can receive a signal through a wireless channel and output it to a processor (1105), and transmit the signal output from the processor (1105) through a wireless channel.

[0220] Memory can store programs and data necessary for the operation of the terminal. Additionally, memory can store control information or data included in signals transmitted and received by the terminal. Memory may be composed of storage media or combinations of storage media, such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memory units.

[0221] Additionally, the processor (1105) can control a series of processes to enable the terminal to operate according to the above-described embodiment. For example, the processor (1105) can control the components of the terminal to receive a DCI composed of two layers and receive a plurality of PDSCHs simultaneously. There may be multiple processors, and the processor (1105) can perform the control operation of the terminal components by executing a program stored in memory.

[0222] FIG. 12 is a drawing illustrating the structure of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0223] Referring to FIG. 12, the base station may include a transceiver unit, which refers to a base station receiver (1200) and a base station transmitter (1210), a memory (not shown), and a base station processing unit (1205, or a base station control unit or processor). Depending on the communication method of the base station described above, the transceiver unit (1200, 1210), memory, and base station processing unit (1205) 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 components or fewer components than the components described above. In addition, the transceiver unit (1200, 1210), memory, and processor may be implemented in the form of a single chip.

[0224] The transceiver (1200, 1210) can transmit and receive signals with a terminal. Here, the signal may include control information and data. To this end, the transceiver (1200, 1210) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver (1200, 1210), and the components of the transceiver (1200, 1210) are not limited to an RF transmitter and an RF receiver.

[0225] Additionally, the transceiver (1200, 1210) can receive a signal through a wireless channel and output it to a processor (1205), and transmit the signal output from the processor (1205) through a wireless channel.

[0226] Memory can store programs and data necessary for the operation of the base station. Additionally, memory can store control information or data included in signals transmitted and received by the base station. Memory can be composed of storage media or combinations of storage media, such as ROM, RAM, hard disks, CD-ROMs, and DVDs. Additionally, there may be multiple memory units.

[0227] The processor (1205) can control a series of processes to enable the base station to operate according to the embodiments of the present disclosure described above. For example, the processor (1205) can control each component of the base station to configure two layers of DCIs containing allocation information for a plurality of PDSCHs and to transmit them. There may be multiple processors (1205), and the processors can perform control operations on the components of the base station by executing a program stored in memory.

[0228] Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0229] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of this disclosure.

[0230] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), Electrically Erasable Programmable Read Only Memory (EEPROM), magnetic disc storage devices, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0231] Additionally, the program may be stored on an attachable storage device accessible via a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. Such a storage device may be connected to the device performing the embodiment of the present disclosure through an external port. Additionally, a separate storage device on the communication network may be connected to the device performing the embodiment of the present disclosure.

[0232] In the specific embodiments of the present disclosure described above, the components included in the invention are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, or even if a component is expressed in the singular form, it may be composed of a plural form.

[0233] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other variations based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments may be combined and operated as needed. For example, parts of one embodiment of the present disclosure and parts of another embodiment may be combined to operate a base station and a terminal. For example, parts of the first embodiment and the second embodiment of the present disclosure may be combined to operate a base station and a terminal. In addition, although the above embodiments are presented based on an FDD LTE system, other variations based on the technical concept of the above embodiments may be implemented in other systems such as a TDD LTE system, 5G, or NR system.

[0234] Meanwhile, the order of description in the drawings illustrating the method of the present invention does not necessarily correspond to the order of execution, and the order of execution may be changed or executed in parallel.

[0235] Alternatively, drawings describing the method of the present invention may omit some components and include only some components to the extent that the essence of the present invention is not impaired.

[0236] In addition, the method of the present invention may be implemented by combining some or all of the contents included in each embodiment within a scope that does not impair the essence of the invention.

[0237] Various embodiments of the present disclosure have been described above. The foregoing description of the present disclosure is for illustrative purposes only and is not limited to the embodiments disclosed. Those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present disclosure. The scope of the present disclosure is defined by the claims set forth below rather than by the foregoing detailed description, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included within the scope of the present disclosure.

Claims

1. In a method of operation of a base station in a wireless communication system, A step of transmitting SRS configuration information to a UE (user equipment) including an SRS resource set containing a plurality of SRS resources for sounding reference signal (SRS) antenna switching; A step of receiving an SRS transmitted with the same transmission power by performing SRS antenna switching on a plurality of receiving antenna ports of the above UE; A step of transmitting a downlink reference signal to the UE using a downlink reference signal resource associated with the above SRS antenna switching; A step of receiving a measurement report including received power measured for each of the plurality of receiving antenna ports of the UE; and A method comprising the step of identifying an insertion loss (IL) imbalance of the UE by comparing the received power of an SRS transmitted for each of the plurality of receiving antenna ports of the UE with the received power measured for each of the plurality of receiving antenna ports of the UE included in the measurement report.

2. In Paragraph 1, A method further comprising the step of receiving UE capability information from the UE, the information including that reception of the downlink reference signal resource associated with the SRS antenna switching and execution of the measurement report are possible. The above SRS resource set is a method associated with the above downlink reference signal.

3. In Paragraph 1, A method in which at least one of the period of the SRS antenna switching, the transmission of the downlink reference signal using the downlink reference signal resource associated with the SRS antenna switching, and the period of the measurement report are configured to correspond.

4. In Paragraph 1, A method comprising the step of receiving from the UE at least one scheduling request among the transmission of the downlink reference signal using the downlink reference signal resource associated with the SRS antenna switching and the measurement report.

5. In Paragraph 1, The above measurement report is, A method comprising information related to the received power of a downlink reference signal resource corresponding to each SRS resource for the above SRS antenna switching.

6. In a method of operation of UE (user equipment) in a wireless communication system, A step of receiving SRS configuration information from a base station, including an SRS resource set containing a plurality of SRS resources for sounding reference signal (SRS) antenna switching; A step of mapping SRS resources included in the SRS resource set to a plurality of receiving antenna ports of the UE based on the above SRS setting information; A step of transmitting SRS with the same transmission power by performing antenna switching on the plurality of receiving antenna ports above; A step of receiving a downlink reference signal transmitted from the base station using a downlink reference signal resource associated with the SRS antenna switching through the plurality of receiving antenna ports; For each of the plurality of receiving antenna ports, a step of measuring the receiving power of the downlink reference signal; and A method comprising the step of transmitting to the base station a measurement report including received power measured for each of the plurality of receiving antenna ports.

7. In Paragraph 6, A method further comprising the step of transmitting UE capability information to the base station, the information including that reception of the downlink reference signal resource associated with the SRS antenna switching and execution of the measurement report are possible.

8. In Paragraph 6, A method in which at least one of the period of the SRS antenna switching, the transmission of the downlink reference signal using the downlink reference signal resource associated with the SRS antenna switching, and the period of the measurement report are configured to correspond.

9. In Paragraph 6, A method further comprising the step of transmitting the downlink reference signal using the downlink reference signal resource associated with the SRS antenna switching and transmitting at least one scheduling request among the measurement reports to the base station.

10. In Paragraph 6, The above measurement report is, A method comprising information related to the received power of a downlink reference signal resource corresponding to each SRS resource for the above SRS antenna switching.

11. Regarding base stations: At least one transceiver; At least one processor communicatively coupled to the above at least one transceiver; and It includes at least one memory that is communicationally coupled to the above at least one processor and stores instructions, and The above instructions are executed individually or in any combination by the above at least one processor, so that the base station: SRS configuration information including an SRS resource set containing multiple SRS resources for SRS (sounding reference signal) antenna switching is transmitted to the UE (user equipment), and SRS antenna switching is performed on a plurality of receiving antenna ports of the above UE to receive an SRS transmitted with the same transmission power, and Using a downlink reference signal resource associated with the above SRS antenna switching, a downlink reference signal is transmitted to the above UE, and Receive a measurement report including received power measured for each of the plurality of receiving antenna ports of the above UE, and A base station that identifies insertion loss (IL) imbalance of the UE by comparing the received power of the SRS transmitted for each of the plurality of receiving antenna ports of the UE with the received power measured for each of the plurality of receiving antenna ports of the UE included in the measurement report.

12. In Paragraph 11, the above commands are the base station: A base station that transmits UE capability information to the base station, including information that reception of the downlink reference signal resource associated with the above SRS antenna switching and execution of the above measurement report are possible.

13. In Paragraph 11, The above measurement report is, A base station comprising information related to the received power for a downlink reference signal resource corresponding to each of the SRS resources for the above SRS antenna switching.

14. Regarding UE (user equipment): At least one transceiver; At least one processor communicatively coupled to the above at least one transceiver; and It includes at least one memory that is communicationally coupled to the above at least one processor and stores instructions, and The above instructions are executed individually or in any combination by the above at least one processor, so that the UE: Receive SRS configuration information from a base station, including an SRS resource set containing a plurality of SRS resources for sounding reference signal (SRS) antenna switching, and Based on the above SRS configuration information, SRS resources included in the above SRS resource set are mapped to a plurality of receiving antenna ports of the UE, and For the plurality of receiving antenna ports above, the antenna switching of the SRS is performed to transmit the SRS with the same transmission power, and A downlink reference signal transmitted from the base station using a downlink reference signal resource associated with the SRS antenna switching is received through the plurality of receiving antenna ports, and For each of the above plurality of receiving antenna ports, the received power of the downlink reference signal is measured, and A UE that transmits a measurement report including received power measured for each of the plurality of receiving antenna ports to the base station.

15. In Paragraph 14, The above measurement report is, A UE comprising information related to the received power for a downlink reference signal resource corresponding to each of the SRS resources for the above SRS antenna switching.

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