Method and apparatus for reporting CSI in wireless communication system

Abstract

The present disclosure relates to a 5G communication system or a 6G communication system that supports higher data rates than 4G communication systems such as Long Term Evolution (LTE). Provided is a method for efficiently selecting an optimal beam on the basis of channel state information (CSI) in a 5G or 6G communication system. A method performed by a user equipment (UE) in a wireless communication system is provided. The method includes receiving a message including configuration information for CSI reporting from a base station, receiving a plurality of CSI reference signals (RSs) on different beams from the base station, generating a precoding matrix for the plurality of CSI-RSs based on the configuration information, and transmitting a CSI report calculated based on the precoding matrix to the base station.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly to a method and apparatus for reporting channel state information (CSI) in a wireless communication system. Background Art

[0002] Considering the development of wireless communication from generation to generation, the relevant technologies have been mainly developed for human-oriented services such as voice calls, multimedia services, and data services. With the commercialization of 5G (fifth generation) communication systems, the number of connected devices is expected to grow exponentially, and more and more devices will be connected to the communication network. Examples of connected devices include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to develop in various forms, such as augmented reality glasses, virtual reality headsets, and holographic devices. In order to provide various services by connecting hundreds of billions of devices and things in the 6G (sixth generation) era, efforts have been made to develop improved 6G communication systems. Therefore, 6G communication systems are also called super 5G systems.

[0003] The 6G communication system, which is expected to be commercialized around 2030, will have a peak data rate of terabit per second (bps) and a wireless delay of less than 100 microseconds. This speed will be 50 times that of the 5G communication system, and the wireless delay will be one-tenth of that of the 5G communication system.

[0004] To achieve such high data rates and ultra-low latency, 6G communication systems are being considered for deployment in the terahertz (THz) frequency band (e.g., 95 gigahertz (GHz) to 3THz band). Since the path loss and atmospheric absorption in the THz band are more severe than in the millimeter wave band introduced in 5G, technologies that can ensure the signal transmission distance (i.e., coverage) will become more critical. As the main technologies to ensure coverage, it is necessary to develop radio frequency (RF) components, antennas, new waveforms with better coverage than orthogonal frequency division multiplexing (OFDM), beamforming and massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and multi-antenna transmission technologies such as massive antennas. In addition, new technologies to improve the coverage of THz band signals, such as metamaterial-based lenses and antennas, orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS), are also under discussion.

[0005] In addition, to improve spectrum efficiency and overall network performance, the following technologies are being developed for 6G communication systems: full-duplex technology, which enables uplink and downlink transmissions to use the same frequency resources simultaneously; network technology for comprehensive utilization of satellites, high altitude platform stations (HAPS), etc.; improved network structure, which is used to support mobile base stations, etc., and to optimize and automate network operations; dynamic spectrum sharing technology through conflict avoidance based on spectrum usage prediction; utilization of artificial intelligence (AI) in wireless communications, which is used to utilize AI from the design stage of developing 6G and build in end-to-end AI support functions to improve overall network operations; and next-generation distributed computing technology, which overcomes the limitations of UE computing capabilities through network-accessible ultra-high-performance communication and computing resources (such as mobile edge computing (MEC), cloud, etc.). In addition, efforts are continuing to strengthen connectivity between devices, optimize networks, promote the softwareization of network entities, and increase the openness of wireless communications by designing new protocols for 6G communication systems, developing mechanisms to implement hardware-based security environments and secure use of data, and developing technologies to protect privacy.

[0006] It is expected that the development of 6G communication systems will bring a new hyper-connected experience in the field of hyper-connectivity including human-to-machine (P2M) and machine-to-machine (M2M). In particular, it is expected that services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas can be provided through 6G communication systems. In addition, services such as remote surgery, industrial automation, and emergency response for improving safety and reliability will also be provided through 6G communication systems, enabling these technologies to be applied to various fields such as industry, medical care, automobiles, and home appliances. In a wireless communication system, channel state information (CSI) can be used to measure the channel state between a terminal and a base station. In addition, the terminal can use CSI feedback to enable the base station to select a suitable beam. In order to more efficiently select the best beam, a method can be considered in which the best beam is determined directly based on CSI by the terminal rather than the base station (e.g., gNodeB or gNB).

[0007] The above information is provided as background information only to assist in understanding the present disclosure. No determination or assertion is made as to whether any of the above may be used as prior art for the present disclosure. Summary of the invention

[0008] Technical Solution

[0009] The present disclosure relates to a wireless communication network, and more particularly to a terminal and a communication method thereof in a wireless communication system.

[0010] According to one aspect of the present disclosure, a method performed by a user equipment (UE) in a wireless communication system is provided. The method includes: receiving a message including configuration information for a channel state information (CSI) report from a base station; receiving a plurality of CSI reference signals (CSI-RS) on different beams from the base station; generating a precoding matrix for the plurality of CSI-RS based on the configuration information; and sending a CSI report calculated based on the precoding matrix to the base station, wherein the CSI report includes information about a CSI-RS among the plurality of CSI-RSs that maximizes the expected throughput. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The following description in conjunction with the accompanying drawings will more clearly show the above and other aspects, features and advantages of certain embodiments of the present disclosure:

[0012] Figure 1 An example of a wireless communication environment according to an embodiment of the present disclosure is shown;

[0013] Figure 2 An example of a configuration of a base station in a wireless communication system according to an embodiment of the present disclosure is shown;

[0014] Figure 3 An example of a configuration of a terminal in a wireless communication system according to an embodiment of the present disclosure is shown;

[0015] Figure 4 shows a beam scanning operation according to an embodiment of the present disclosure;

[0016] Figure 5 Various types of channel state information reference signal (CSI-RS) resources allocated by a base station to a terminal according to an embodiment of the present disclosure are shown;

[0017] Figure 6 A method for configuring a group of CSI-RS resources according to an embodiment of the present disclosure is shown;

[0018] Figure 7 The sequence of a CSI reporting operation including information about an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown;

[0019] Figure 8 A signal flow of a CSI report including information about an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown;

[0020] Fig. 9 The present invention shows the order of CSI reporting including information about the best CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure;

[0021] Fig.10A method for determining a representative CSI-RS resource indicator (CRI) for each CSI-RS resource set in a wireless communication system according to an embodiment of the present disclosure is shown;

[0022] Fig.11 A method for selecting a precoding weight applied to CSI calculation in a wireless communication system according to an embodiment of the present disclosure is shown;

[0023] Fig.12 The present invention shows the order of CSI reporting including information about the best CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure;

[0024] Fig.13 A method for determining a representative CRI for each CSI-RS resource set in a wireless communication system according to an embodiment of the present disclosure is shown;

[0025] Fig.14 A method for determining a representative CRI for each CSI-RS resource set in a wireless communication system according to an embodiment of the present disclosure is shown;

[0026] Fig.15 Configuration information of a CSI-RS resource superset for grouping multiple CSI-RS resource sets in a wireless communication system according to an embodiment of the present disclosure is shown;

[0027] Fig.16 The configuration information of the offset parameter for each CSI-RS resource in the wireless communication system according to the embodiment of the present disclosure is shown;

[0028] Fig.17 The configuration information of the offset parameter for each CSI-RS resource set in the wireless communication system according to the embodiment of the present disclosure is shown;

[0029] Fig.18 The configuration information of the CSI-RS resource superset in the wireless communication system according to the embodiment of the present disclosure is shown;

[0030] Fig.19 A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown;

[0031] Fig. 20 A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown;

[0032] Fig.21 A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown;

[0033] Fig. 22A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown; and

[0034] Fig.23 A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown.

[0035] The same reference numerals are used throughout the drawings to denote the same elements. DETAILED DESCRIPTION

[0036] Aspects of the present disclosure are to address at least the above-mentioned problems and / or disadvantages and provide at least the advantages described below. Therefore, one aspect of the present disclosure provides a terminal in a wireless communication system and a communication method thereof.

[0037] Aspects of the present disclosure are to address at least the above-mentioned problems and / or disadvantages and provide at least the advantages described below. Therefore, one aspect of the present disclosure provides an apparatus and method capable of effectively providing a service in a wireless communication system.

[0038] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments.

[0039] According to one aspect of the present disclosure, a method performed by a user equipment (UE) in a wireless communication system is provided. The method includes: receiving a message including configuration information for a channel state information (CSI) report from a base station; receiving a plurality of CSI reference signals (CSI-RS) on different beams from the base station; generating a precoding matrix for the plurality of CSI-RS based on the configuration information; and sending a CSI report calculated based on the precoding matrix to the base station, wherein the CSI report includes information about a CSI-RS among the plurality of CSI-RS that maximizes the expected throughput.

[0040] According to another aspect of the present disclosure, a method performed by a base station in a wireless communication system is provided. The method includes: sending a message including configuration information for channel state information (CSI) reporting to a user equipment (UE); sending a plurality of CSI reference signals (CSI-RS) on different beams to the UE; and receiving a CSI report from the UE, wherein the CSI is based on a precoding matrix according to the configuration information, and the CSI report includes information about a CSI-RS among the plurality of CSI-RSs that maximizes the expected throughput.

[0041] According to another aspect of the present disclosure, a user equipment (UE) in a wireless communication system is provided. The UE includes at least one transceiver and at least one processor functionally connected to the at least one transceiver, wherein the at least one processor is configured to: receive a message including configuration information for a channel state information (CSI) report from a base station; receive multiple CSI reference signals (CSI-RS) on different beams from the base station; generate a precoding matrix for the multiple CSI-RS based on the configuration information; and send a CSI report calculated based on the precoding matrix to the base station, wherein the CSI report includes information about a CSI-RS among the multiple CSI-RS that maximizes the expected throughput.

[0042] According to another aspect of the present disclosure, a base station in a wireless communication system is provided. The base station includes at least one transceiver and at least one processor functionally connected to the at least one transceiver, wherein the at least one processor is configured to: send a message including configuration information for channel state information (CSI) reporting to a user equipment (UE); send multiple CSI reference signals (CSI-RS) on different beams to the UE; and receive a CSI report from the UE, wherein the CSI is based on a precoding matrix according to the configuration information, and the CSI report includes information about a CSI-RS among multiple CSI-RSs that maximizes the expected throughput.

[0043] Various embodiments of the present disclosure provide an apparatus and method for efficiently providing a service in a wireless communication system.

[0044] Other aspects, advantages, and salient features of the disclosure will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure.

[0045] Mode for carrying out the invention

[0046] The following description in conjunction with the accompanying drawings is intended to assist in a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in understanding, but these are to be considered exemplary only. Therefore, one of ordinary skill in the art will recognize that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and structures may be omitted for clarity and brevity.

[0047] The terms and words used in the following description and claims are not limited to their literal meanings, but are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Therefore, it will be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is for illustrative purposes only and is not intended to limit the present disclosure as defined by the appended claims and their equivalents.

[0048] It will be understood that references in the singular include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0049] Hereinafter, various embodiments of the present disclosure will be described based on a hardware method. However, various embodiments of the present disclosure include techniques using both hardware and software, and thus various embodiments of the present disclosure do not exclude the software aspect.

[0050] In the following description, for the convenience of description, terms referring to device elements (e.g., control unit, processor, artificial intelligence (AI) model, encoder, decoder, autoencoder (AE), and neural network (NN) model), terms referring to data (e.g., signal, feedback, report, report, information, parameter, value, bit, and codeword), etc. are exemplarily used. Therefore, the present disclosure is not limited to the terms used below, and other terms with equivalent technical meanings may be used.

[0051] In the present disclosure, various embodiments will be described using terms adopted in some communication standards (eg, the 3rd Generation Partnership Project (3GPP)), but these are for illustration purposes only. Through modification, various embodiments of the present disclosure may also be applied to other communication systems.

[0052] Figure 1 A wireless communication system according to an embodiment of the present disclosure is shown.

[0053] Figure 1 Base station 110, terminal 120 and terminal 130 are shown, which are some nodes using wireless channels in a wireless communication system. Figure 1 Only one base station is shown, but another base station that is the same as or similar to base station 110 may be further included.

[0054] The base station 110 is a network infrastructure that provides wireless access for the terminals 120 and 130. The base station 110 has a coverage range of a specific geographical area defined based on a signal transmittable distance. In addition to a base station, the base station 110 may also be referred to as an "access point (AP)", "eNodeB (eNB)", "gNodeB (gNB)", "fifth generation node (5G node)", "sixth generation node (6G node)", "radio point", "transmit / receive point (TRP)" or other terms with equivalent technical meanings.

[0055] Each of the terminals 120 and 130 is a device used by a user and communicates with the base station 110 through a wireless channel. In some cases, at least one of the terminals 120 and 130 may operate without user participation. That is, at least one of the terminals 120 and 130 is a device that performs machine type communication (MTC) and may not be carried by a user. In addition to terminals, each of the terminals 120 and 130 may also be referred to as "user equipment (UE)", "mobile station", "subscriber station", "customer premises equipment (CPE)", "remote terminal", "wireless terminal", "electronic device", "user equipment" or other terms with similar or equivalent technical meanings.

[0056] The base station 110, the terminal 120, and the terminal 130 can send and receive wireless signals in the millimeter wave frequency band (for example, 28 GHz, 30 GHz, 38 GHz, 60 GHz, more than 60 GHz, etc.). In this case, in order to improve the channel gain, the base station 110, the terminal 120, and the terminal 130 can perform beamforming. Beamforming may include transmit beamforming and receive beamforming. That is, the base station 110, the terminal 120, and the terminal 130 can give directionality to the transmitted signal or the received signal. To this end, the base station 110 and the terminals 120 and 130 can select the service beams 112, 113, 121, and 131 through a beam search or beam management process. After the service beams 112, 113, 121, and 131 are selected, communication can be performed through resources having a quasi-co-location (QCL) relationship with the resources that sent the service beams 112, 113, 121, and 131.

[0057] Figure 2 A configuration example of a base station in a wireless communication system according to an embodiment of the present disclosure is shown.

[0058] According to various embodiments of the present disclosure, the base station 110 may be referred to as a network for the sake of convenience. Figure 2The configuration shown in can be understood as the configuration of the base station 110. Terms such as "unit" and "device" used below refer to a unit that processes at least one function or operation, and this can be implemented by hardware, software, or a combination of hardware and software.

[0059] Reference Figure 2 , the base station 110 may include a wireless communication unit 210 , a backhaul communication unit 220 , a storage unit 230 , and a controller 240 .

[0060] The wireless communication unit 210 performs the function of sending or receiving a signal through a wireless channel. For example, the wireless communication unit 210 performs the conversion function between the baseband signal and the bit stream according to the physical layer standard of the system. For example, when data is transmitted, the wireless communication unit 210 generates complex symbols by encoding and modulating the transmitted bit stream. In addition, when data is received, the wireless communication unit 210 recovers the received bit stream by demodulating and decoding the baseband signal. In addition, the wireless communication unit 210 up-converts the baseband signal into a radio frequency (RF) band signal, then transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal.

[0061] To this end, the wireless communication unit 210 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. In addition, the wireless communication unit 210 may include multiple transmit / receive paths. In addition, the wireless communication unit 210 may include at least one antenna array, which includes multiple antenna elements. In terms of hardware, the wireless communication unit 210 may include a digital unit and an analog unit, and the analog unit may include multiple subunits based on operating power, operating frequency, etc.

[0062] The wireless communication unit 210 may transmit or receive a signal. To this end, the wireless communication unit 210 may include at least one transceiver. For example, the wireless communication unit 210 may transmit a synchronization signal, a reference signal, system information, a message, control information, or data. In addition, the wireless communication unit 210 may perform beamforming.

[0063] The wireless communication unit 210 transmits and receives signals as described above. Therefore, all or part of the wireless communication unit 210 may be referred to as a "transmitter", "receiver" or "transceiver". In addition, in the following description, transmission and reception through a wireless channel refer to the above-mentioned processing performed by the wireless communication unit 210.

[0064] The backhaul communication unit 220 provides an interface for communicating with other nodes in the network. That is, the backhaul communication unit 220 converts a bit stream sent from the base station 110 to another node (e.g., another access node, another base station, an upper node, a core network, etc.) into a physical signal, and converts a physical signal received from other nodes into a bit stream.

[0065] The storage unit 230 stores data such as basic programs, application programs, and configuration information required for the operation of the base station 110. The storage unit 230 may include a memory. The storage unit 230 may include a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. In addition, the storage unit 230 may provide the stored data according to the request of the controller 240.

[0066] The controller 240 controls the overall operation of the base station 110. For example, the controller 240 sends and receives signals through the wireless communication unit 210 or the backhaul communication unit 220. In addition, the controller 240 records data on the storage unit 230 and reads data therefrom. In addition, the controller 240 can perform protocol stack functions required by the communication standard. To this end, the controller 240 may include at least one processor.

[0067] Figure 2 The configuration of the base station 110 shown is only an example of a base station. The base station examples for implementing various embodiments of the present disclosure are not limited to Figure 2 That is, according to various embodiments, some configurations may be added, deleted or changed.

[0068] Despite Figure 2 The base station is described as an entity in the specification, but the present disclosure is not limited thereto. According to various embodiments of the present disclosure, the base station may be implemented to form an access network with distributed deployment as well as integrated deployment. According to an embodiment, the base station may be divided into a central unit (CU) and a digital unit (DU), so that the CU may be implemented to perform upper layer functions (e.g., radio link control (RLC), packet data convergence protocol (PDCP), and radio resource control (RRC)), and the DU may be implemented to perform lower layer functions (e.g., media access control (MAC) and physical layer (PHY)). The DU of the base station may form beam coverage on a wireless channel.

[0069] Figure 3 A configuration example of a terminal in a wireless communication system according to an embodiment of the present disclosure is shown.

[0070] Figure 3The illustrated configuration may be understood as a configuration of the terminals 120 and 130. Terms such as "unit" and "device" used below may mean a unit that processes at least one function or operation, and this may be implemented by hardware, software, or a combination of hardware and software.

[0071] Reference Figure 3 , the terminals 120 and 130 may include a communication unit 310 , a storage unit 320 , and a controller 330 .

[0072] The communication unit 310 performs the function of sending or receiving a signal through a wireless channel. For example, the communication unit 310 performs the conversion function between the baseband signal and the bit stream according to the physical layer standard of the system. For example, when data is sent, the communication unit 310 generates complex symbols by encoding and modulating the transmitted bit stream. In addition, when data is received, the communication unit 310 recovers the received bit stream by demodulating and decoding the baseband signal. In addition, the communication unit 310 up-converts the baseband signal to a radio frequency (RF) band signal, then sends the RF band signal through an antenna, and down-converts the RF band signal received by the antenna to a baseband signal. For example, the communication unit 310 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0073] In addition, the communication unit 310 may include multiple transmit / receive paths. In addition, the communication unit 310 may include an antenna unit. The communication unit 310 may include at least one antenna array, which includes multiple antenna elements. In terms of hardware, the communication unit 310 may include digital circuits and analog circuits (e.g., radio frequency integrated circuits (RFIC)). The digital circuits and analog circuits may be implemented as a package. In addition, the communication unit 310 may include multiple radio frequency chains. The communication unit 310 may perform beamforming. In order to give directionality to the signal to be sent or received according to the configuration of the controller 330, the communication unit 310 may apply beamforming weights to the signal. According to an embodiment, the communication unit 310 may include a radio frequency (RF) module (or RF unit). The RF module may include a first RF circuit associated with an antenna and a second RF circuit associated with baseband processing. The first RF circuit may be referred to as RF-A (antenna). The second RF circuit may be referred to as RF-B (baseband).

[0074] The communication unit 310 may send or receive a signal. To this end, the communication unit 310 may include at least one transceiver. The communication unit 310 may receive a downlink signal. The downlink signal may include a synchronization signal (SS), a reference signal (RS) (e.g., a cell-specific reference signal (CRS) and a demodulation (DM)-RS), system information (e.g., a master information block (MIB), a system information block (SIB), remaining system information (RMSI), and other system information (OSI)), a configuration message, control information, downlink data, etc. In addition, the communication unit 310 may send an uplink signal. The uplink signal may include a random access-related signal (e.g., a random access preamble (RAP) (or message 1 (Msg1) or message 3 (Msg3)), a reference signal (e.g., a sounding reference signal (SRS) or DM-RS), or a power headroom report (PHR).

[0075] In addition, the communication unit 310 may include different communication modules to process signals of different frequency bands. In addition, the communication unit 310 may include multiple communication modules to support a variety of different wireless access technologies. For example, different wireless access technologies may include Bluetooth Low Energy (BLE), Wireless Fidelity (Wi-Fi), Wi-Fi Gigabit (WiGig), cellular networks (e.g., Long Term Evolution (LTE) or New Radio (NR)), etc. In addition, different frequency bands may include ultra-high frequency (SHF) (e.g., 2.5 GHz and 5 GHz) bands and millimeter wave (e.g., 38 GHz, 60 GHz, etc.) bands. In addition, the communication unit 310 may use wireless access technology in the same way on different frequency bands (e.g., unlicensed bands for licensed assisted access (LAA) and citizen broadband radio service (CBRS) (e.g., 3.5 GHz)).

[0076] The communication unit 310 transmits and receives signals as described above. Therefore, all or part of the communication unit 310 may be referred to as a "transmitter", "receiver" or "transceiver". In addition, in the following description, transmission and reception through a wireless channel refer to the above-mentioned processing performed by the communication unit 310.

[0077] The storage unit 320 stores data such as basic programs, application programs, and configuration information required for the operation of the terminal 120. The storage unit 320 may include a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. In addition, the storage unit 320 may provide the stored data according to a request of the controller 330.

[0078] The controller 330 controls the overall operation of the terminals 120 and 130. For example, the controller 330 sends and receives signals through the communication unit 310. In addition, the controller 330 records data on the storage unit 320 and reads data therefrom. In addition, the controller 330 can perform the protocol stack functions required by the communication standard. To this end, the controller 330 may include at least one processor. The controller 330 may include at least one processor or microprocessor, or may be a part of a processor. In addition, the communication unit 310 and a part of the controller 330 may be referred to as a cellular processor (CP). The controller 330 may include various modules for performing communication. According to various embodiments, the controller 330 may control the terminal to perform operations according to various embodiments.

[0079] Despite Figure 3 Although not shown in the figure, according to various embodiments of the present disclosure, the terminals 120 and 130 may further include a CSI selection unit. According to an embodiment, the CSI selection unit included in the terminal may calculate the CSI according to the type of precoding scheme received from the base station. In an embodiment, when a precoding scheme including a precoding matrix indicator (PMI) is configured in the terminal by high-level signaling (e.g., an RRC message) received from the base station, the CSI selection unit may calculate the CSI based on a codebook. In this case, the CSI may include a precoding matrix indicator (PMI). In this embodiment, the above-mentioned CSI calculation method may be referred to as a codebook-based CSI calculation method.

[0080] In an embodiment, when a precoding scheme that does not include PMI is configured in the terminal by high-layer signaling (e.g., an RRC message) received from a base station, the CSI selection unit may generate a precoding matrix corresponding to one of the configured precoding schemes, and may calculate the CSI based on the generated precoding matrix. In this case, the CSI may include one or more of a channel quality indicator (CQI) and a rank indication (RI). In this embodiment, the above-mentioned CSI calculation method may be referred to as a non-codebook-based CSI calculation method. In addition, when a precoding scheme that does not include PMI is configured in the terminal (e.g., a non-codebook-based CSI calculation method), a method for generating a precoding matrix corresponding to each precoding scheme may be pre-configured in the base station and the terminal, or the base station may configure the method in the terminal by high-layer signaling (e.g., an RRC message).

[0081] In an embodiment, the CSI calculation method according to the precoding scheme may be performed by the controller 330 and the storage unit 320. In this case, the controller 330 may include one or more processors. The one or more processors may include the functions of a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or a digital signal processor (DSP). The one or more processors may be controlled to calculate the CSI according to the predefined operating rules or base station configuration information stored in the storage unit 320. The CSI selection unit may not be included in the controller 330, but may be included as a separate component.

[0082] Figure 3 The configuration of the terminals 120 and 130 shown is only an example of a terminal, and the terminal examples for implementing various embodiments of the present disclosure are not limited to Figure 3 That is, according to various embodiments, some configurations may be added, deleted or changed.

[0083] In the present disclosure, a method for comparing the performance between CSI reference signal (CSI-RS) resources with different effective isotropic radiated power (EIRP) and a CSI feedback method may be described. The operation of a terminal reporting information about a channel state (e.g., a measurement result of a channel or beam for sending and / or receiving a signal) to a base station may be referred to as CSI feedback or CSI reporting, and CSI feedback and CSI reporting may have the same meaning. In this case, EIRP may refer to a value obtained by subtracting cable loss from the sum of transmit power and antenna gain. The terminal may compare the performance between CSI-RS resources (e.g., CSI-RS resources allocated to analog beams). In order to enable the terminal to send CSI feedback to the base station based on performance comparison, different beamforming schemes may be applied to each cell area. In this case, the CSI-RS resources may have different values ​​in at least one of port, density, beam width, or strength, etc. Each base station may run analog beamforming and digital beamforming in a hybrid form to ensure beam coverage. In this case, a hybrid type of beamforming can be used to maintain at least the same beam coverage in the upper mid-band (i.e., a frequency band higher than the mid-band, such as the 10 to 24 GHz band, which belongs to the upper mid-band) as in the mid-band (e.g., 3.5 GHz).

[0084] In an embodiment, the central area includes coverage near the base station, and the base station can ensure coverage through a single analog beam. In this case, in order to ensure coverage through a single analog beam, the number of CSI-RS ports per beam can be increased and the number of antenna elements per CSI-RS port can be reduced.

[0085] In an embodiment, the edge area includes a coverage area far away from the base station, and the base station can ensure the coverage area through multiple analog beams. In this case, in order to ensure the coverage area through multiple analog beams, the number of CSI-RS ports per beam can be reduced and the number of antenna elements per CSI-RS port can be increased.

[0086] Therefore, the CSI feedback overhead for beam management in each cell area may be greatly increased. In order to reduce the CSI feedback overhead, the terminal can determine the best beam (e.g., CSI-RS resource) among all CSIs and send only information about the selected best CSI-RS resource to the base station. In this case, the terminal can determine the best CSI-RS resource among CSI-RS resources with different numbers of CSI-RS ports. Hereinafter, in an embodiment of the present disclosure, a method for a terminal to determine the best CSI-RS resource among CSI-RS resources with different numbers of CSI-RS ports will be described.

[0087] Figure 4 A beam scanning operation according to an embodiment of the present disclosure is shown.

[0088] Reference Figure 4 , a cell may be divided into a first area (area 1) to a third area (area 3), the first area may be referred to as a central area, the second area may be referred to as a middle area, and the third area may be referred to as an edge area. However, this area division of a cell is an example of a terminal sending a CSI report for each cell area, and is not limited to this embodiment.

[0089] Reference Figure 4 , different beamforming schemes can be applied to each cell area of ​​a certain cell. That is, different types of beams (for example, types of CSI-RS resources) can be used for each cell area. In an embodiment, the coverage of the first area can be guaranteed by one analog beam, and each beam can include 256 CSI-RS ports. The coverage of the second area can be guaranteed by multiple analog beams, and each beam can include 32 CSI-RS ports. The coverage of the third area can be guaranteed by more analog beams than the second area, and each beam can include 4 CSI-RS ports. However, the number of CSI-RS ports contained in each beam is only an example, and can be more or less than the number of CSI-RS ports per beam described above. In addition, the value of at least one of the density, beam width, or beam strength of the analog beam may vary from region to region.

[0090] In addition, the base station can perform digital beamforming based on the precoding matrix (precoding beamforming). When the base station performs analog beamforming through multiple antennas, the base station can send a narrow beam over a long distance in a specific direction, but it may be difficult to cover the entire cell (or a specific area of ​​the cell) at one time. Therefore, the base station can divide the coverage of the entire cell (or a specific area of ​​the cell) into multiple areas corresponding to the analog beam width, and turn the beam in sequence to cover the coverage of the entire cell (or specific area). The above operation of the base station can be referred to as beam scanning.

[0091] Figure 5 Various types of CSI-RS resources allocated by a base station to a terminal according to an embodiment of the present disclosure are shown.

[0092] Reference Figure 5 , the base station may send CSI-RS to the terminal through different types of CSI-RS resources for each cell area. In this case, the base station may configure information about CSI-RS resources in the terminal through high-layer signaling (e.g., a radio resource control (RRC) message). The information about CSI-RS resources configured in the terminal may include at least one of frequencyDomainAllocation, nrofPorts, firstOFDMSymbolInTimeDomain, cdm-Type, density, or freqBand. In this case, frequencyDomainAllocation may include frequency domain information allocated to CSI-RS resources, nrofPorts may include information about the number of CSI-RS ports, firstOFDMSymbolInTimeDomain may include time domain information allocated to CSI-RS resources, cdm-Type may include code division multiplexing (CDM) type information of CSI-RS resources, density may include information about beam density, and freqBand may include information about CSI-RS resource frequency bands. The EIRP (e.g., one of frequencyDomainAllocation, nrofPorts, firstOFDMSymbolInTimeDomain, cdm-Type, density, or freqBand) of CSI-RS resources in each area configured by the base station may be different from each other.

[0093] In the above embodiments, the operation of configuring CSI report configuration information in the terminal through high-layer signaling (e.g., RRC message) is described, but the terminal may receive CSI report configuration information from the base station through at least one of high-layer signaling (e.g., RRC message), MAC layer signaling (e.g., MAC control element (CE)), or control information (e.g., downlink control information (DCI)). In the following embodiments of the present disclosure, the configuration information may also be configured in the terminal or indicated to the terminal.

[0094] Figure 6 A method for configuring a group of CSI-RS resources according to an embodiment of the present disclosure is shown.

[0095] Reference Figure 6 , the base station can configure a CSI-RS set including multiple CSI-RS resources to select (determine or identify) the best CSI-RS resource for each cell area. The base station can configure the CSI-RS set for each cell area using the method for configuring the CSI-RS set.

[0096] In an embodiment, the base station may configure a CSI-RS resource set identifier (ID) (e.g., NZP-CSI-RS-ResourceSetId) for each of the first to third regions. The NZP-CSI-RS-ResourceSetId of the first region may be configured as 1. Since the first region may be covered by one simulated beam, the CSI-RS resource set of the first region (e.g., NZP-CSI-RS-ResourceSet y) may include one CSI-RS resource ID (e.g., NZP-CSI-RS-ResourceSet = {v}). In addition, the NZP-CSI-RS-ResourceSetId of the second region may be configured as 2. Since the second region may be covered by multiple simulated beams, the CSI-RS resource set of the second region (e.g., NZP-CSI-RS-ResourceSet y+1) may include multiple CSI-RS resource IDs (e.g., NZP-CSI-RS-ResourceId = {w, w+1, w+2, w+3}). In addition, the NZP-CSI-RS-ResourceSetId of the third region may be configured as 3. Since the third region may be covered by more simulated beams than the second region, the CSI-RS resource set of the third region (e.g., NZP-CSI-RS-ResourceSet y+2) may include multiple CSI-RS resource IDs (e.g., NZP-CSI-RS-ResourceId={x, x+1, ..., x+N}). In this case, N may refer to the number of simulated beams transmitted, which corresponds to the value of the beam coverage.

[0097] In addition, the base station may configure information about uplink resources for the terminal to send CSI reports in the terminal through high-layer signaling (e.g., RRC message). In an embodiment, CSI report resources (e.g., CSI-ReportConfig z) and resources for channel measurement (e.g., resourcesForChannelMeasurement y) for CSI-RS in the first region may be configured in the terminal. In addition, CSI report resources (e.g., CSI-ReportConfig z+1) and resources for channel measurement (e.g., resourcesForChannelMeasurement y+1) for CSI-RS in the second region may be configured in the terminal. In addition, CSI report resources (e.g., CSI-ReportConfig z+2) and resources for channel measurement (e.g., resourcesForChannelMeasurement y+2) for CSI-RS in the third region may be configured in the terminal.

[0098] In this case, the terminal needs to send a CSI report to the base station for each CSI-RS resource set. Therefore, uplink overhead may be generated due to the CSI report of the terminal. In addition, the above embodiment shows a method for the base station to configure the CSI-RS resource set using the same type of beam for each cell area, but the CSI-RS resource set is not limited to being configured only by the same type of beam. However, when the base station configures the CSI-RS resource set using the same type of beam, the number of CSI reports of the terminal may be reduced compared to the case where the CSI-RS resource set contains different types of beams. Therefore, when the base station configures the CSI-RS resource set using the same type of beam, the effect of reducing uplink overhead may be enhanced. In this case, the same type of beam may refer to CSI-RS resources with the same bandwidth part (BWP) ID, density, and nrofPorts, in addition to the CSI-RS resources used for interference measurement.

[0099] exist Figure 6In the embodiment, the process of the terminal sending a CSI report to the base station periodically is shown, but the above embodiment is not limited to the periodic CSI reporting process. The base station can configure the configuration information related to the irregular CSI report in the terminal through the RRC message. The terminal can send the CSI report to the base station irregularly based on the configuration information. The periodic or irregular CSI reporting operation of the terminal can be pre-configured in the terminal through the RRC message. According to each operation of the CSI report of various embodiments of the present disclosure, within the scope that can be clearly understood by those skilled in the art, it can be applied to various CSI reporting scenarios between the terminal and the base station. In addition, the various embodiments of the present disclosure may include all the operations, some operations, or a combination of some operations described below, and within the achievable scope, a combination of some operations of periodic, semi-periodic or semi-continuous CSI reports is possible. The operation of the CSI report is described below, including all signal flows of periodic, irregular and semi-continuous CSI reports.

[0100] The following will describe a method for a terminal to send a CSI report to a base station in conjunction with the present disclosure. The base station may receive a CSI report based on a CSI-RS sent to the terminal from the terminal. The base station may identify the channel state between the base station and the terminal through the CSI report, and determine (or select) the best beam that maximizes the throughput. Specifically, the base station may determine the best beam based on at least one of a channel quality indicator (CQI), a precoding matrix indicator (PMI), or a rank indicator (RI) contained in the CSI report. In this case, the terminal may estimate (measure or calculate) the CQI based on the PMI. Specifically, the terminal may select a PMI from a codebook received from the base station according to the RI, and calculate a signal to interference plus noise ratio (SINR) based on the PMI. In addition, the terminal may determine the CQI based on the calculated signal to interference plus noise ratio (SINR). The above-mentioned PMI-based CQI determination method may be an operation of a codebook-based CSI reporting method. Beamforming based on PMI or based on a synchronization signal block (SSB) resource indicator (SSBRI) may be used for codebook-based CSI reporting.

[0101] Both PMI-based beamforming and sounding reference signal (SRS) (or transmit antenna selection (TAS))-based beamforming can be used for each cell area. SRS-based beamforming may have greater gain than PMI-based beamforming. However, since SRS is a reference signal sent by the terminal to the base station, there may be limitations (e.g., terminal power limitations) compared to PMI-based beamforming. Therefore, the downlink transmission beamforming scheme expected for each cell area may be different. In particular, in the upper and mid-frequency bands, the coverage of SRS may be limited due to transmission power and path loss. The beamforming scheme expected for each cell area can be classified as shown in Table 1 below.

[0102] Table 1

[0103] area Expected downlink transmission beamforming scheme 1 Based on SRS(TAS) 2 SRS (TAS) based and / or PMI based 3 PMI-based and / or SSBRI-based

[0104] In the embodiments, again refer to Figure 4 , since the terminal closest to the base station is located in the first area, there may be fewer restrictions affecting SRS-based beamforming. Therefore, the base station can use SRS-based beamforming for the first area. In addition, since the distance between the terminal and the base station in the second area is relatively long compared to the first area, SRS-based beamforming and / or PMI-based beamforming can be used. In addition, since the terminal in the third area is located at the edge of the cell, the base station can use PMI-based beamforming and / or SSBRI-based beamforming. However, since the terminal does not know the transmission precoding weights generated by zero forcing (ZF) or singular value decomposition (SVD) precoding, the CQI estimated (or calculated) by the terminal may be difficult to reflect the gain of SRS-based beamforming.

[0105] Figure 7 The sequence of a CSI reporting operation including information on an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown.

[0106] Reference Figure 7 , the terminal can select (determine or identify) the best CSI-RS resource to reduce uplink overhead, and can send a CSI report including information about the selected best CSI-RS resource to the base station.

[0107] In operation 710, the terminal may receive a higher layer message (eg, an RRC message) from a base station. The RRC message may include information on a CSI-RS resource and a CSI report resource.

[0108] In operation 720, the terminal may receive a plurality of CSI-RSs based on the configuration information received from the base station. The plurality of CSI-RSs received by the terminal may be included in one CSI-RS resource set. Alternatively, the plurality of CSI-RSs received by the terminal may be included in a plurality of CSI-RS resource sets, and the plurality of CSI-RS resource sets may refer to Figure 5 CSI-RS resource set for each cell area in the embodiment.

[0109] In operation 730, the terminal may determine a method for calculating the CSI according to a precoding scheme (e.g., precodingScheme) included in an RRC message received from the base station. In this case, one or more precoding schemes configured in the terminal may be included, which will be described in the following Fig.11 Described in detail in.

[0110] In operation 740, when the precoding scheme included in the RRC message includes PMI, the terminal may calculate CSI by using a codebook scheme (e.g., a CQI calculation method based on PMI). The CSI calculation method in the codebook scheme may be a method of calculating CQI based on a codebook received from a base station, and may be combined with Figure 6 The CQI calculation method described in the embodiments is the same.

[0111] In operation 750, in an embodiment, when the precoding scheme included in the RRC message does not include PMI, the terminal may calculate CSI by using a non-codebook scheme (e.g., a CQI calculation method not based on PMI). The non-codebook scheme may be a method in which the terminal generates a precoding matrix corresponding to a precoding scheme other than PMI and generates CQI based on the generated precoding matrix. Therefore, the non-codebook scheme may be different from Figure 6 The CQI calculation method described in the embodiment is different. In this case, the base station may preconfigure a method for generating a precoding matrix corresponding to the precoding scheme in the terminal (for example, preconfigure the method in the terminal through an RRC message).

[0112] In the embodiment, although Figure 7 Not shown, the terminal may send UE capability information to the base station. The base station may configure the terminal to send UE capability information through an RRC message or a MAC control element (CE), and may pre-configure the CSI calculation process in the terminal based on the UE capability information sent by the terminal according to the configuration information.

[0113] The terminal may select (or decide) a CSI calculation method according to the type of precoding scheme included in the RRC message received from the base station. Therefore, when the precoding scheme includes PMI, the terminal may decide to use a codebook scheme to calculate CSI. When the precoding scheme does not include PMI, the terminal may decide to use a non-codebook scheme to calculate CSI. However, even when the precoding scheme includes PMI, the terminal may decide to calculate CSI by using a codebook scheme according to its own capabilities.

[0114] In operation 760, the terminal may select a representative CSI-RS resource indicator (CRI) from the CSI-RS resource set. The representative CRI may indicate a beam (e.g., CSI-RS resource) preferred by the terminal in each CSI-RS resource set. Alternatively, the representative CRI may indicate at least one CSI-RS resource having the best channel state among the CSI-RS resources included in each CSI-RS resource set.

[0115] In operation 770, the terminal may transmit a CSI report including information on the best CSI-RS resource (eg, one CSI-RS resource having the best channel state among one or more CSI-RS resources indicated by the representative CRI) to the base station.

[0116] Figure 8 A signal flow of a CSI report including information on an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown.

[0117] Reference Figure 8 , which can be described Figure 7 The signal flow between the base station and the terminal during the CSI reporting process of the terminal.

[0118] In operation 810, the base station may transmit an RRC message (eg, an RRC reconfiguration message) including configuration information for a CSI-RS and a CSI report to the terminal.

[0119] In operation 820, the terminal may transmit an RRC reconfiguration complete message (eg, an acknowledgement (ACK) signal) to the base station in response to the RRC reconfiguration message.

[0120] In operations 830 and 840, the base station may sequentially send CSI-RS to the terminal through the CSI-RS resource of each CSI-RS resource set ID based on the configuration information included in the RRC reconfiguration message. Alternatively, the base station may non-sequentially send CSI-RS to the terminal through the CSI-RS resource of each CSI-RS resource set ID based on the configuration information included in the RRC reconfiguration message received in operation 810. In this case, the method for sending CSI-RS (e.g., sequential or non-sequential transmission) may be pre-configured in the terminal according to the RRC reconfiguration message received from the base station in operation 810.

[0121] In operation 850, the terminal may calculate CSI for each CSI-RS resource set based on the precoding scheme included in the RRC reconfiguration message received from the base station. In addition, the terminal may select the best CSI-RS resource, and the best CSI-RS resource may be a CSI-RS resource corresponding to one of the CRIs representing each CSI-RS resource set.

[0122] In operation 860, the terminal may send a CSI report including channel state information (e.g., information about a channel corresponding to the best CSI-RS resource selected by the terminal in operation 850) to the base station on a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) via uplink control information (UCI).

[0123] Fig. 9 The order of CSI reporting including information on optimal CSI-RS resources in a wireless communication system according to an embodiment of the present disclosure is shown.

[0124] Reference Fig. 9 , which can describe the CSI reporting operation of the terminal based on the non-codebook solution. The CSI reporting based on the non-codebook solution described in this embodiment can follow Figure 7 Therefore, the following will be omitted. Figure 7 Describe the overlapping parts.

[0125] In operation 910, the terminal may receive an RRC message (eg, an RRC reconfiguration message) including configuration information for transmitting a representative CRI to a base station. The RRC message may include information on a CSI-RS resource and a CSI report resource.

[0126] In operation 920, the terminal may receive a plurality of CSI-RSs based on the configuration information received from the base station. The plurality of CSI-RSs received by the terminal may be transmitted through CSI-RS resources included in one or more CSI-RS resource sets.

[0127] In operation 930, when the precoding scheme included in the configuration information received from the base station includes the PMI, and the UE capability is greater than or equal to the UE capability threshold that can generate the precoding matrix, the terminal may decide to calculate the CSI based on the non-codebook scheme. In this case, it can be assumed that the terminal knows the channel matrix received through the CSI-RS. The method for generating the precoding matrix may vary depending on the type of precoding scheme contained in the configuration information. Specifically, if the precoding scheme is ZF, the precoding matrix can be calculated as W=H(HTH)-1. Alternatively, if the precoding scheme is a regularized ZF, the precoding matrix can be calculated as W=H(HTH+αI)-1 (α: a scalar value used to regularize HTH). The above method is only an example of a method for generating a precoding matrix according to the type of precoding scheme, and there may be other methods besides the above calculation formula. In addition, the method for generating the precoding matrix may vary depending on the type of precoding scheme contained in the configuration information. In this case, the UE capability threshold may refer to the computing power per hour, the size of the available storage space, etc. In addition, it does not necessarily include only the case where the UE capability is greater than or equal to the threshold, but may also include the case where the UE capability exceeds the threshold.

[0128] In operation 940, the terminal may calculate the SINR for each rank based on the precoding matrix generated in operation 930, and determine (select or identify) a rank and a CQI having a maximum throughput among the calculated SINRs.

[0129] In operation 950, the terminal may send a CSI report to the base station, including information on CSI-RS resources corresponding to the rank and CQI determined in operation 940 (or information on a representative CRI). Thus, the terminal may receive a downlink signal from the base station through a channel determined based on the CSI report.

[0130] Fig.10 A method for determining a representative CRI for each CSI-RS resource set in a wireless communication system according to an embodiment of the present disclosure is shown.

[0131] Referring to Fig.10 in the above Fig. 9 In the CSI reporting method based on the non-codebook scheme of the above embodiment, the terminal may select a representative CRI based on a precoding matrix generated according to configuration information.

[0132] In an embodiment, the terminal may calculate CSI for each CSI-RS resource set (e.g., Figure 6 the CSI-RS resource sets y, y+1, and y+2 configured for each cell area in

[0133] ) based on the generated precoding matrix, and select a CRI indicating the CSI-RS with the best channel state from the calculated CSI as the representative CRI. In an embodiment, the terminal may select CSI-RS resources with IDs x, w+2, and v+1 as representative CRIs for each cell area, and select a CRI indicating one of the selected CSI-RS resources (e.g., the CSI-RS resource with ID v+1) as the representative CRI for all representative sets. The selection of the above representative CRI may have the same meaning as the selection of the CSI-RS resource that maximizes the expected throughput (e.g., the product of spectral efficiency and rank).

[0134] The number of best CRIs that the terminal can select from the CSI-RS resource set configured in the terminal by the base station is not necessarily limited to 1. The terminal may select one or more best CRIs from only one CSI-RS resource set, and may not select the best CRI from another CSI-RS resource set. The above-mentioned best CRI selection method of the terminal may be pre-configured through an RRC message (e.g., an RRC reconfiguration message) received from the base station.

[0135] Fig.11 A method for selecting a precoding weight applied to CSI calculation in a wireless communication system according to an embodiment of the present disclosure is shown.

[0136] Reference Fig.11 , in the above Fig. 9 In the CSI reporting method based on the non-codebook scheme of the embodiment, the configuration information for CSI reporting configured in the terminal by the base station through an RRC message (e.g., an RRC reconfiguration message) may include information about the precoding scheme. The configuration information may include one or more precoding schemes in the form of "ENUMERATED". However, in the configuration information, one or more precoding schemes may be configured in the form of "CHOICE" and are not limited to the form of "ENUMERATED" or "CHOICE". The type of precoding scheme may include at least one of PMI, ZF, regularized ZF, or minimum mean square error (MMSE).

[0137] Fig.12 The order of CSI reporting including information on optimal CSI-RS resources in a wireless communication system according to an embodiment of the present disclosure is shown.

[0138] Reference Fig.12 , which can describe the CSI reporting operation of the terminal based on the codebook solution. The CSI reporting based on the codebook solution described in this embodiment can follow Figure 7 Therefore, the following will be omitted. Figure 7 Describe the overlapping parts.

[0139] In operation 1210, the terminal may receive an RRC message (eg, an RRC reconfiguration message) including configuration information for transmitting a representative CRI to a base station. The RRC message may include information on a CSI-RS resource and a CSI report resource.

[0140] In operation 1220, the terminal may receive a plurality of CSI-RSs based on the configuration information received from the base station. The plurality of CSI-RSs received by the terminal may refer to CSI-RSs transmitted through CSI-RS resources included in one or more CSI-RS resource sets.

[0141] In operation 1230, when the precoding scheme included in the configuration information received from the base station does not include the PMI, or even if the precoding scheme includes the PMI but the UE capability is less than or equal to the UE capability threshold that can generate the precoding matrix, the terminal may decide to calculate the CSI based on the codebook scheme. The terminal may calculate the CSI for each CSI-RS using the codebook scheme. In an embodiment, the CSI calculation method using the codebook scheme may be the same as the above Figure 6 In this case, the UE capability threshold may refer to the computing capability per hour, the size of the available storage space, etc. In addition, it does not necessarily include only the case where the UE capability is less than or equal to the threshold, but may also include the case where the UE capability is less than the threshold.

[0142] In operation 1240, in an embodiment, the terminal may select a representative CRI indicating a CSI-RS that maximizes the expected throughput based on the CSI calculated in operation 1230. In this case, the terminal may consider an offset of the CQI, a reference signal received power (RSRP), or other key performance indicators (KPIs) when calculating the expected throughput. The offset may be determined according to the number of ports representing the CSI-RS resources of each CSI-RS resource set.

[0143] In an embodiment, the terminal may consider a performance indicator (eg, RSRP) other than the expected throughput. Therefore, the terminal may select a representative CRI indicating a CSI-RS that maximizes RSRP.

[0144] The terminal may transmit a CSI report including information about the selected representative CRI to the base station. Therefore, the terminal may receive a downlink signal from the base station through a channel determined based on the CSI report.

[0145] Fig.13 A method for determining a representative CRI for each CSI-RS resource set in a wireless communication system according to an embodiment of the present disclosure is shown.

[0146] Reference Fig.13 , in the above Fig.12 In the CSI reporting method based on the codebook solution of the embodiment, the terminal can select a representative CRI based on the PMI.

[0147] In an embodiment, the terminal may provide each CSI-RS resource set (eg, Figure 6Calculate CSI for CSI-RS resource sets y, y+1, and y+2 configured for each cell area, and select, from the calculated CSI, the CRI indicating the CSI-RS with the best channel state as the representative CRI. In this case, all CSI-RS resources included in a CSI-RS resource set may have the same number of CSI-RS ports. Additionally, the number of CSI-RS ports for each CSI-RS resource set may be different (or the same). In an embodiment, the terminal may select, as the representative CRI for each cell area, the CSI-RS resources with IDs x, w+2, and v+1, and select, from the selected CSI-RS resources, the CRI indicating one of them (e.g., the CSI-RS resource with ID v+1) as the representative CRI for all representative sets. The selection of the above representative CRI may have the same meaning as the selection of the CSI-RS resource that maximizes the expected throughput (e.g., the product of spectral efficiency and rank value).

[0148] In an embodiment, the terminal may select the CRI of up to M CSI-RS resources (e.g., M < N, where N is the maximum number of representative CRIs to be selected by the terminal) for each CSI-RS resource set. For example, in the case of N = 4 and M = 2, if the best CRIs of the first and second priorities are selected for a certain CSI-RS resource set, the best CRI of the third priority may be selected from CSI-RS resource sets other than the CSI-RS resource set for which the best CRIs of the first and second priorities are selected.

[0149] The number of best CRIs that can be selected by the terminal from the CSI-RS resource sets configured in the terminal by the base station is not necessarily limited to 1. The terminal may select one or more best CRIs from only one CSI-RS resource set and may not select the best CRI from another CSI-RS resource set. The above method for the terminal to select the best CRI may be pre-configured through an RRC message (e.g., an RRC reconfiguration message) received from the base station.

[0150] Fig.14 A method for determining a representative CRI for each CSI-RS resource set in a wireless communication system according to an embodiment of the present disclosure is shown.

[0151] Refer to Fig.14 , in the CSI reporting method based on the codebook scheme in the above Fig.12 embodiment, the terminal may select a representative CRI based on the PMI. Specifically, Figure 6Unlike the method of configuring a CSI-RS resource set for each cell area in , the terminal can configure a CSI-RS resource set containing all CSI-RS resources. Therefore, the terminal can select the CRI of the CSI-RS indicating the best channel state from the CSI-RS resource set containing all CSI-RS resources based on the PMI as the representative CRI. In this case, each CSI-RS resource included in the CSI-RS resource set can have a different number of CSI-RS ports. In an embodiment, the terminal can select a CRI indicating one of all CSI-RS resources (for example, a CSI-RS resource with an ID of v+1) as the representative CRI. The selection of the above representative CRI has the same meaning as the selection of the CSI-RS resource that maximizes the expected throughput (for example, the product of the spectral efficiency and the rank value).

[0152] Fig.15 Configuration information of a CSI-RS resource superset for grouping multiple CSI-RS resource sets in a wireless communication system according to an embodiment of the present disclosure is shown.

[0153] Reference Fig.15 , regarding the above Figure 8 The CSI calculation method based on the non-codebook solution in the embodiment may describe a method that can save resources used by the terminal to select a representative CRI for each CSI-RS resource set.

[0154] In an embodiment, the base station may configure multiple CSI-RS resource sets including one or more CSI-RS resources, and configure a CSI-RS resource superset (e.g., NZP-CSI-RS-ResourceSuperSet) including two or more of the multiple CSI-RS resource sets. Figure 8 In the embodiment of the present invention, the terminal needs to use the same number of resources as the number of CSI-RS resource sets to select the representative CRI (for example, a total of 3 CSI-RS resource sets y to y+1). However, according to this embodiment, the terminal only needs to use the same number of resources as the number of CSI-RS resource supersets including two or more of the multiple CSI-RS resource sets to select the representative CRI. Figure 8 Compared with the embodiment, the terminal can select a smaller number of representative CRIs, thereby achieving the effect of saving resources by reducing the number of selected representative CRIs.

[0155] In an embodiment, the base station may send an RRC message (e.g., an RRC reconfiguration message) to the terminal to change the configuration value of the CSI-RS resource superset. In this case, the RRC message (e.g., an RRC reconfiguration message) may include information for reconfiguring the CSI-RS resource superset configuration value in the terminal.

[0156] In an embodiment, the base station may instruct the terminal to activate or deactivate a CSI-RS resource set included in a CSI-RS resource superset through medium access control (MAC) layer signaling (eg, MAC CE) to change the configuration value of the CSI-RS resource superset.

[0157] In an embodiment, the base station may instruct the terminal to activate or deactivate a CSI-RS resource set included in a CSI-RS resource superset through control information (eg, downlink control information (DCI)) to change a configuration value of the CSI-RS resource superset.

[0158] The above-mentioned "CSI-RS resource superset" refers to a collection of multiple CSI-RS resource sets, which is nothing more than a name used to refer to multiple grouped CSI-RS resource sets. In addition, the information about the multiple grouped CSI-RS resource sets that can be included in the RRC message (e.g., RRC reconfiguration message) may include identification information of the multiple grouped CSI-RS resource sets, or information indicating one or more of the maximum number.

[0159] Fig.16 Configuration information of an offset parameter for each CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown.

[0160] Reference Fig.16 , a method for configuring an offset parameter may be described for a terminal to compare the performance between CSI-RS resources with different precoding schemes. The offset parameter may refer to an offset used to compare the performance between multiple CSI-RS resources included in a CSI-RS resource set. Fig.13 , when the terminal calculates CSI based on the codebook scheme, the configuration information about the offset that can be considered when selecting the best CSI-RS resource from a CSI-RS resource set may include one or more information in the following Table 2.

[0161] Table 2

[0162]

[0163] When the terminal selects the best CSI-RS based on the expected throughput, the configuration information included in the RRC message (e.g., the RRC reconfiguration message) may include information about the offset of the KPI that the terminal may consider when calculating the expected throughput. The offset parameter in Table 2 may be configured for each CSI-RS resource to be used when comparing the performance between CSI-RSs with different expected beamforming gains. The terminal may compare the performance between CSI-RSs with different beamforming gains based on the offset of each CSI-RS resource.

[0164] The power offset in Table 2 may refer to the SINR gain difference for each beamforming scheme included in the configuration information, and the power offset may be configured in decibels (dB). In addition, the CQI offset may refer to the CQI difference aligned according to the SINR gain difference for each beamforming scheme included in the configuration information, and the CQI offset may be configured in integers. In addition, the spectrum offset may refer to the spectrum efficiency difference aligned according to the SINR gain difference for each beamforming scheme included in the configuration information, and the spectrum offset may be configured in bps / Hz.

[0165] However, the offset parameter in Table 2 is only an example, and the offset parameter is not limited to the information included in Table 2. Therefore, the configuration information included in the RRC message (e.g., the RRC reconfiguration message) may include additional offset parameters (e.g., at least one of the offset parameters of RSRP, RI, or other KPIs) for comparing performance between CSI-RS resources with different expected beamforming gain values.

[0166] Fig.17 Configuration information of an offset parameter for each CSI-RS resource set in a wireless communication system according to an embodiment of the present disclosure is shown.

[0167] Reference Fig.17 , a method for configuring an offset parameter may be described, which a terminal uses to compare the performance between representative CSI-RS resources corresponding to representative CRIs of CSI-RS resource sets. The offset parameter may refer to an offset used to select representative CRIs of all CSI-RS resource sets. Again referring to Fig.12 , when the terminal calculates CSI based on the codebook scheme, the configuration information about the offset that can be considered when selecting the best CSI-RS resource from the representative CSI-RS resources may include one or more information in the following Table 3.

[0168] Table 3

[0169] parameter Configuration for each CSI-RS resource set ID compared to the reference CSI-RS resource set Power offset for collection SINR gain differences according to beamforming schemes CQI offset for aggregation CQI differences aligned with SINR gain differences according to beamforming scheme differences Spectral efficiency offset for the set Spectral efficiency differences aligned with SINR gain differences according to beamforming scheme differences

[0170] When the terminal selects the best CSI-RS in the representative CSI-RS resource based on the expected throughput, the configuration information included in the RRC message (e.g., RRC reconfiguration message) may include information about the offset of the KPI that the terminal may consider when calculating the expected throughput. The terminal may compare the performance between CSI-RSs with different beamforming gains based on the offset for each CSI-RS resource.

[0171] The power offset in Table 3 may refer to the SINR gain difference for each beamforming scheme included in the configuration information, and the power offset may be configured in decibels (dB). In addition, the CQI offset may refer to the CQI difference aligned according to the SINR gain difference for each beamforming scheme included in the configuration information, and the CQI offset may be configured in integers. In addition, the spectrum offset may refer to the spectrum efficiency difference aligned according to the SINR gain difference for each beamforming scheme included in the configuration information, and the spectrum offset may be configured in bps / Hz.

[0172] However, the offset parameter in Table 3 is only an example, and the offset parameter is not limited to the information included in Table 3. Therefore, the configuration information included in the RRC message (e.g., the RRC reconfiguration message) may include an additional offset parameter (e.g., at least one of the offsets of RSRP, RI, or other KPIs) for comparing the performance between representative CSI-RS resources with different expected beamforming gain values.

[0173] Fig.18 Configuration information of a CSI-RS resource superset in a wireless communication system according to an embodiment of the present disclosure is shown.

[0174] Reference Fig.18 , a method for configuring the configuration information about the CSI-RS resource superset for each ID can be described. Fig.15 , the base station can configure the CSI-RS resource superset to save the resources required for the terminal to select a representative CRI. According to an embodiment of the present disclosure, the base station can configure information about the CSI-RS resource superset for each ID in the configuration information included in the RRC message (e.g., the RRC reconfiguration message). Therefore, the terminal that receives the RRC message (e.g., the RRC reconfiguration message) can identify (or check) the CSI-RS resource sets included in the CSI-RS resource superset and the CSI-RS resource sets included in each CSI-RS resource set included in the configuration information. When the terminal selects a representative CRI for each CSI-RS resource superset based on the configuration information according to an embodiment of the present disclosure, the delay caused by selecting the representative CRI can be reduced.

[0175] Fig.19 A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown.

[0176] Reference Fig.19, a method for a terminal to select the best CSI-RS resource among CSI-RS resources through an optional metric in a specific information element (IE) may be described. The base station may configure the IE required for performance comparison between CSI-RS resources and the optional metric in each IE in the terminal through an RRC message (e.g., an RRC reconfiguration message). In an embodiment, the IE required for performance comparison between CSI-RS resources (e.g., report quality) may include at least one of cri-RI-PMI-CQI, cri-RI-i1, cri-RI-i1-CQI, cri-RI-CQI, cri-RSRP, ssb-Index-RSRP, or cri-RI-LI-PMI-CQI. In addition, the optional metric in each IE (e.g., metric quality) may include at least one of thpBased or rsrpBased. The IE required for performance comparison between CSI-RS resources and the optional metric in each IE are not limited to the above examples. In this case, the configuration information may include the optional metric in each IE in the form of "ENUMERATED". However, the optional metrics in each IE in the configuration information may be configured in the form of "CHOICE" and is not limited to the form of "ENUMERATED" or "CHOICE".

[0177] Fig. 20 A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown.

[0178] Reference Fig. 20 , in order to enable the terminal to select the best CSI-RS resource, a method based on Fig.19 The CSI-RS resource selection method of the embodiment disclosed in the disclosure uses a configured metric (e.g., metric quality) to maximize the objective function. The performance metric corresponding to the optional metric (e.g., metric quality) configuration in each IE can be configured by one of the methods in Table 4 below.

[0179] Table 4

[0180]

[0181]

[0182] In the above Table 4, "thpBased" may include a method of selecting a CSI-RS resource that maximizes the expected data rate, and "rsrpBased" may include a method of selecting a CSI-RS resource with the highest RSRP. SE(i) may refer to the spectral efficiency mapped to CQI index i. For example, the value of FSE(10) may be 4.5234 bps / Hz. The performance metric values ​​included in Table 4 may be based on the configuration of the metric quality and the offset value (e.g., Fig.16 and Fig.17 The offset in the embodiment may vary.

[0183] In an embodiment, if the metric quality is thpBased, then according to the above Fig.13 and Fig.14 In each embodiment of the present invention, the method for selecting the CSI-RS resource that maximizes the data transmission rate may be different. Fig.13 In the embodiment of the present invention, in method 1-1, the performance metric may be expressed as the product of the value that maximizes FSE (measured CQI + CQI offset for the set) and the measured RI. In method 1-2, the performance metric may be expressed as the product of the value that maximizes (FSE (measured CQI) + spectral efficiency offset for the set) and the measured RI. In addition, in Fig.14 In the embodiment of the present invention, in methods 1-3, the performance metric can be expressed as the product of the value that maximizes FSE (measured CQI + CQI offset) and the measured RI. In methods 1-4, the performance metric can be expressed as the product of the value that maximizes (FSE (measured CQI) spectral efficiency offset) and the measured RI.

[0184] In an embodiment, if the metric quality is rsrpBased, then according to the above Fig.13 and Fig.14 In each embodiment of the present invention, the method for selecting the CSI-RS resource that maximizes the data transmission rate may be different. Fig.13 In the embodiment of (ie, method 2-1), the performance metric may be expressed as the sum of the value that maximizes the measured RSRP and the power offset for the set. Fig.14 In the embodiment (ie, method 2-2), the performance metric can be expressed as the sum of the power offset and the value that maximizes the measured RSRP.

[0185] In an embodiment, in the case of other metric qualities, the performance metric may be expressed as a value that maximizes a KPI corresponding to the metric quality (eg, taking into account offset values ​​such as SINR, RSRQ, CQI, etc.).

[0186] Fig. 20The operation of the terminal periodically sending a CSI report to the base station is shown, but the above embodiment is not limited to the periodic CSI reporting process. The base station can configure the configuration information related to the non-periodic CSI report in the terminal through an RRC message. The terminal can send a CSI report to the base station non-periodically based on the configuration information. The periodic or non-periodic CSI reporting operation of the terminal can be pre-configured in the terminal through an RRC message. Each operation on the CSI report in the various embodiments of the present disclosure can be applied to various CSI reporting scenarios between the terminal and the base station within the scope that can be clearly understood by those skilled in the art. In addition, the various embodiments of the present disclosure may include all the operations, some operations, or a combination of some operations described below, and within the achievable scope, a combination of some operations of periodic, semi-periodic or semi-persistent CSI reports is possible. The operation of the CSI report is described below, including all signal flows of periodic, non-periodic and semi-persistent CSI reports.

[0187] Fig.21 A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown.

[0188] Reference Fig.21 ,according to Fig. 20 In the embodiment disclosed in, the terminal can determine the spectrum efficiency value according to the value of the CQI index i. However, the required signal-to-noise ratio (SNR) value can be obtained according to a specific simulation or analysis method. Fig.21 The table in may include a modulation scheme, a coding rate×1024, a spectrum efficiency, and a required signal-to-noise ratio (SNR) value according to a CQI index. In this case, the required SNR may refer to a minimum SNR value that satisfies the mapping of spectrum efficiency to each CQI index.

[0189] The terminal can be based on Fig.21 The base station can pre-configure the table containing the spectrum efficiency and required SNR value of the CQI index in the terminal through an RRC message (eg, an RRC reconfiguration message).

[0190] Fig. 22 A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown.

[0191] Reference Fig. 22In an embodiment, in a CSI calculation method based on a non-codebook scheme, a method in which a terminal calculates a CQI based on a lookup table may be described. When the terminal uses non-codebook-based beamforming (e.g., beamforming based on a precoding matrix generated according to ZF or SVD), the expected CQI index in the non-codebook scheme may be defined based on the CQI calculated by a codebook-based beamforming (i.e., PMI-based beamforming) method. That is, the terminal may use a CQI value to which an offset configuration value is applied for CSI calculation in a non-codebook scheme. In this case, when the configuration information of an RRC message (e.g., an RRC reconfiguration message) configures the precoding scheme as a non-codebook scheme (e.g., when the precoding scheme does not include PMI) and does not include a separate offset configuration value, the terminal may calculate the CQI based on a lookup table.

[0192] In an embodiment, in the CSI calculation method based on the codebook solution, the above Fig.16 and Fig.17 When the offset in the embodiment is applied as a single value, an offset configuration method may be described. The reference CSI-RS resource may refer to the CSI-RS resource with the highest EIRP and to which PMI-based beamforming is applied. This is because the CSI-RS resource aligned with the simulated beam with the smallest performance variation range based on the precoding weight may be selected as a reference. The CSI-RS resource of the reference CSI-RS resource for each offset parameter is shown in Table 5 below.

[0193] Table 5

[0194]

[0195] In an embodiment, the offset parameter power offset (for a set) may be configured as the beamforming gain of the reference CSI-RS resource (set) minus the beamforming gain of the corresponding CSI-RS resource (set) (unit: dB).

[0196] In an embodiment, for the offset parameter CQI offset (for a set), the terminal may estimate the SNR difference between the reference CSI-RS resource (set) and the corresponding CSI-RS resource (set) by the above-mentioned power offset (for a set). SNR may refer to the result obtained by multiplying the transmit power, the channel gain, and the value obtained by dividing the beamforming gain by the noise (SNR = transmit power × channel gain × beamforming gain / noise). In addition, even if the expected SNR difference (≈ power offset) for each CQI index is not linear, the terminal may refer to a robust CQI index or average calculation to infer the CQI index difference based on the expected SNR difference. In addition, the terminal may determine the CQI offset by the inferred CQI index difference.

[0197] In an embodiment, for the offset parameter spectral efficiency offset (for the set), the terminal may use the same method as the above-mentioned CQI offset (for the set) determination method, or adopt the same steps as at least one step in the above-mentioned CQI offset (for the set) determination method to determine the offset of the spectral efficiency difference based on the expected SNR difference (≈power offset).

[0198] Fig.23 A method for selecting an optimal CSI-RS resource in a wireless communication system according to an embodiment of the present disclosure is shown.

[0199] Reference Fig.23 , a method for configuring the configuration information included in the RRC message (e.g., RRC reconfiguration message) by the base station for each combination of CSI-RS resource characteristics may be described. The base station may configure the configuration information for CSI calculation and CSI reporting of the terminal in the terminal, and according to the above embodiments (e.g., Figure 6 ), configure information about CSI-RS resources in the terminal for each CSI-RS resource ID or CSI-RS resource set ID.

[0200] In an embodiment, the base station may configure information about CSI-RS resources in the terminal for each CSI-RS resource feature (for example, including at least one of bwp-Id, density, or number of ports (nrofPorts)). Specifically, the base station may configure the same offset value for CSI-RS resources with a specific bwp-Id, density, or number of ports. In this case, the base station may not configure IE (for example, for Fig.19 This is because, when a CSI-RS resource is configured for each CSI-RS resource feature, a CSI-RS resource with a corresponding feature may include an offset configuration (e.g., at least one of a power offset, a CQI offset, and a spectral efficiency offset).

[0201] According to various embodiments of the present disclosure, a method performed by a terminal in a wireless communication system may include: receiving a message including configuration information for a channel state information (CSI) report from a base station; receiving multiple CSI reference signals (CSI-RS) on different beams from the base station; generating a precoding matrix for the multiple CSI-RS based on the configuration information; and sending a CSI report calculated based on the precoding matrix to the base station, wherein the CSI report includes information about a CSI-RS among the multiple CSI-RSs that maximizes the expected throughput.

[0202] In an embodiment, the multiple CSI-RS may include at least one CSI-RS set including two or more CSI-RSs, and a plurality of CSI-RSs included in a different CSI-RS set different from the at least one CSI-RS may have different values ​​in at least one of a bandwidth part identifier (bwp-Id), density, and the number of antenna ports.

[0203] In an embodiment, the configuration information may also include configuration information about the at least one CSI-RS set, and two or more CSI-RS included in one CSI-RS set may have the same bwp-Id, density, and number of antenna ports.

[0204] In an embodiment, the configuration information may further include information indicating the type of precoding scheme used to generate the precoding matrix and information on a method of generating the precoding matrix for each type.

[0205] In an embodiment, when the configuration information includes a precoding matrix indicator (PMI), the CSI of each of the multiple CSI-RSs can be calculated based on the PMI, and the expected throughput can be determined based on an offset of a measurement indicator of a channel state between the terminal and the base station.

[0206] According to various embodiments of the present disclosure, a method performed by a base station in a wireless communication system may include: sending a message including configuration information for channel state information (CSI) reporting to a terminal; sending a plurality of CSI reference signals (CSI-RS) on different beams to the terminal; and receiving a CSI report from the terminal, wherein the CSI is based on a precoding matrix according to the configuration information, and the CSI report includes information about a CSI-RS among the plurality of CSI-RSs that maximizes the expected throughput.

[0207] In an embodiment, the multiple CSI-RS may include at least one CSI-RS set including two or more CSI-RSs, and the multiple CSI-RSs included in different CSI-RSs different from the at least one CSI-RS set may have different values ​​in at least one of a bandwidth part identifier (bwp-Id), density, and the number of antenna ports.

[0208] In an embodiment, the configuration information may also include configuration information about the at least one CSI-RS set, and two or more CSI-RS included in one CSI-RS set may have the same bwp-Id, density, and number of antenna ports.

[0209] In an embodiment, the configuration information may further include information indicating the type of precoding scheme used to generate the precoding matrix and information on a method of generating the precoding matrix for each type.

[0210] In an embodiment, when the configuration information includes a precoding matrix indicator (PMI), the CSI of each of the multiple CSI-RSs can be calculated based on the PMI, and the expected throughput can be determined based on an offset of a measurement indicator of a channel state between the terminal and the base station.

[0211] According to various embodiments of the present disclosure, a terminal in a wireless communication system may include: at least one transceiver; and at least one processor functionally connected to the at least one transceiver, wherein the at least one processor is configured to: receive a message including configuration information for a channel state information (CSI) report from a base station; receive a plurality of CSI reference signals (CSI-RS) on different beams from the base station; generate a precoding matrix for the plurality of CSI-RS based on the configuration information; and send a CSI report calculated based on the precoding matrix to the base station, wherein the CSI report includes information about a CSI-RS among the plurality of CSI-RSs that maximizes the expected throughput.

[0212] In an embodiment, the multiple CSI-RS may include at least one CSI-RS set including two or more CSI-RSs, and the multiple CSI-RSs included in different CSI-RS sets may have different values ​​in at least one of bandwidth part identifier (bwp-Id), density, and number of antenna ports.

[0213] In an embodiment, the configuration information may also include configuration information about the at least one CSI-RS set, and two or more CSI-RS included in one CSI-RS set may have the same bwp-Id, density, and number of antenna ports.

[0214] In an embodiment, the configuration information may further include information indicating the type of precoding scheme used to generate the precoding matrix and information on a method of generating the precoding matrix for each type.

[0215] In an embodiment, when the configuration information includes a precoding matrix indicator (PMI), the CSI of each of the multiple CSI-RSs can be calculated based on the PMI, and the expected throughput can be determined based on an offset of a measurement indicator of a channel state between the terminal and the base station.

[0216] According to various embodiments of the present disclosure, a base station in a wireless communication system may include: at least one transceiver; and at least one processor functionally connected to the at least one transceiver, wherein the at least one processor is configured to: send a message including configuration information for channel state information (CSI) reporting to a terminal; send a plurality of CSI reference signals (CSI-RS) on different beams to the terminal; and receive a CSI report from the terminal, wherein the CSI is based on a precoding matrix according to the configuration information, and the CSI report includes information about a CSI-RS among the plurality of CSI-RSs that maximizes the expected throughput.

[0217] In an embodiment, the multiple CSI-RS may include at least one CSI-RS set including two or more CSI-RSs, and the multiple CSI-RSs included in different CSI-RS sets may have different values ​​in at least one of bandwidth part identifier (bwp-Id), density, and number of antenna ports.

[0218] In an embodiment, the configuration information may also include configuration information about the at least one CSI-RS set, and two or more CSI-RS included in one CSI-RS set may have the same bwp-Id, density, and number of antenna ports.

[0219] In an embodiment, the configuration information may further include information indicating the type of precoding scheme used to generate the precoding matrix and information on a method of generating the precoding matrix for each type.

[0220] In an embodiment, when the configuration information includes a precoding matrix indicator (PMI), the CSI of each of the multiple CSI-RSs can be calculated based on the PMI, and the expected throughput can be determined based on an offset of a measurement indicator of a channel state between the terminal and the base station.

[0221] The methods of the embodiments described in the claims or the specification of the present disclosure may be implemented by software, hardware, or a combination of hardware and software.

[0222] For software implementation, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors of an electronic device. One or more programs may include instructions for controlling an electronic device to perform the method of the embodiment described in the claims or specification of the present disclosure.

[0223] Such a program (software module, software) may be stored in a random access memory, a non-volatile memory including flash memory, a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), a magnetic disk storage device, a compact disk (CD)-ROM, a digital versatile disk (DVD) or other optical storage device, and a magnetic tape. Alternatively, it may be stored in a memory that combines some or all of these recording media. Multiple memories may be included.

[0224] In addition, the program can be stored in a connectable storage device, which can be accessed through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), or a storage area network (SAN), or a communication network formed by combining these networks. Such a storage device can access the device that executes the embodiments of the present disclosure through an external port. In addition, a separate storage device on a communication network can access the device that executes the embodiments of the present disclosure.

[0225] In the specific embodiments of the present disclosure, the components included in the present disclosure are expressed in singular or plural form. However, for ease of explanation, singular or plural expression is appropriately selected according to the situation presented, and the present disclosure is not limited to a single component or multiple components. A component expressed in plural form can be configured as a single component, and a component expressed in singular form can be configured as multiple components.

[0226] While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as defined by the following claims and their equivalents.

Claims

1. A method performed by a user equipment UE in a wireless communication system, the method comprising: receiving, from a base station, a message including configuration information for channel state information (CSI) reporting; receiving a plurality of CSI reference signals CSI-RS on different beams from the base station; Based on the configuration information, generate a precoding matrix for the multiple CSI-RSs; as well as sending a CSI report calculated based on the precoding matrix to the base station, The CSI report includes information about a CSI-RS among the multiple CSI-RSs that maximizes the expected throughput.

2. The method according to claim 1, in, The plurality of CSI-RSs include at least one CSI-RS set including two or more CSI-RSs, and Among them, in the at least one CSI-RS set, multiple CSI-RSs in different CSI-RS sets have different values ​​in at least one of the bandwidth part identifier bwp-Id, density or number of antenna ports.

3. The method according to claim 2, in, The configuration information also includes configuration information about the at least one CSI-RS set, and Among them, two or more CSI-RS in a CSI-RS set have the same value in at least one of the bwp-Id, the density or the number of antenna ports. 4 . The method according to claim 1 , wherein the configuration information further includes information indicating a type of a precoding scheme used to generate the precoding matrix, and information on a method of generating the precoding matrix for each type.

5. A method performed by a base station in a wireless communication system, the method comprising: Sending a message including configuration information for channel state information CSI reporting to a user equipment UE; Sending a plurality of CSI reference signals CSI-RS on different beams to the UE; as well as receiving a CSI report from the UE, wherein the CSI is based on a precoding matrix according to the configuration information, and The CSI report includes information about a CSI-RS among the multiple CSI-RSs that maximizes the expected throughput.

6. The method according to claim 5, in, The plurality of CSI-RSs include at least one CSI-RS set including two or more CSI-RSs, and Among them, in the at least one CSI-RS set, multiple CSI-RSs in different CSI-RS sets have different values ​​in at least one of the bandwidth part identifier bwp-Id, density or number of antenna ports.

7. The method according to claim 6, in, The configuration information also includes configuration information about the at least one CSI-RS set, and Wherein, two or more CSI-RSs included in one CSI-RS set have the same value in at least one of the bwp-Id, the density or the number of antenna ports.

8. The method according to claim 5, wherein: The configuration information also includes information indicating a type of a precoding scheme used to generate the precoding matrix, and information on a method of generating the precoding matrix for each type.

9. A user equipment UE in a wireless communication system, the UE comprising: at least one transceiver; as well as at least one processor functionally connected to the at least one transceiver, Wherein, the at least one processor is configured as: receiving a message including configuration information for channel state information (CSI) reporting from a base station, receiving a plurality of CSI reference signals CSI-RS on different beams from the base station, generating a precoding matrix for the plurality of CSI-RS based on the configuration information, and sending a CSI report calculated based on the precoding matrix to the base station, and The CSI report includes information about a CSI-RS among the multiple CSI-RSs that maximizes the expected throughput.

10. The UE according to claim 9, in, The plurality of CSI-RSs include at least one CSI-RS set including two or more CSI-RSs, and Among them, in the at least one CSI-RS set, multiple CSI-RSs in different CSI-RS sets have different values ​​in at least one of the bandwidth part identifier bwp-Id, density or number of antenna ports.

11. The UE according to claim 10, in, The configuration information also includes configuration information about the at least one CSI-RS set, and Among them, two or more CSI-RS in a CSI-RS set have the same value in at least one of the bwp-Id, the density or the number of antenna ports.

12. The UE according to claim 9, wherein: The configuration information also includes information indicating a type of a precoding scheme used to generate the precoding matrix, and information on a method of generating the precoding matrix for each type, and The expected throughput is determined based on an offset of a measurement indicator of a channel state between the UE and the base station.

13. A base station in a wireless communication system, the base station comprising: at least one transceiver; as well as at least one processor functionally connected to the at least one transceiver, Wherein, the at least one processor is configured as: Sending a message including configuration information for channel state information CSI reporting to a user equipment UE, sending a plurality of CSI reference signals CSI-RS on different beams to the UE, and receiving a CSI report from the UE, wherein the CSI is based on a precoding matrix according to the configuration information, and The CSI report includes information about a CSI-RS among the multiple CSI-RSs that maximizes the expected throughput.

14. The base station according to claim 13, in, The plurality of CSI-RSs include at least one CSI-RS set including two or more CSI-RSs, and Among them, in the at least one CSI-RS set, multiple CSI-RSs in different CSI-RS sets have different values ​​in at least one of the bandwidth part identifier bwp-Id, density or number of antenna ports.

15. The base station according to claim 14, in, The configuration information also includes configuration information about the at least one CSI-RS set, and Two or more CSI-RS in a CSI-RS set have the same value in at least one of the bwp-Id, the density or the number of antenna ports.

Images