Method and apparatus for performing improved beam tracking in next generation wireless communication system

Abstract

The disclosure relates to a 6G communication system for implementing an ultra-low latency time and a higher data transmission rate than 4G and 5G communication systems. According to an embodiment of the disclosure, a base station can match (or map) a beam that is highly probable to be selected as an optimal beam at a location of a terminal to a channel state information reference signal (CSI-RS), and can provide the CSI-RS to the terminal. Accordingly, it is possible to increase the likelihood of including a beam having the best performance in a beam corresponding to the CSI-RS. Accordingly, when a beamforming technique operates in a millimeter wave and terahertz frequency band or an ultra-high frequency band or a higher frequency band, beam tracking with improved performance can be performed.

Description

Technical Field

[0001] This disclosure relates to the operation of terminals and base stations in next-generation wireless communication systems. In particular, this disclosure relates to a beam tracking method that improves performance in performing signal transmission / reception between terminals and base stations by applying beamforming technology in systems based on ultra-high frequency bands such as millimeter wave (mmWave) (e.g., 28 GHz, terahertz (THz) or higher), and apparatus capable of performing this method. Background Technology

[0002] A review of the development of wireless communication shows that its development has primarily focused on human-centric service technologies, such as voice-based services, multimedia services, and data services. An exponential increase in connected devices is expected after the commercialization of fifth-generation (5G) communication systems. Examples of things connected to the network might include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve in various forms, such as augmented reality glasses, virtual reality headsets, and holographic devices. Efforts are underway to develop improved 6G communication systems to provide a wide range of services by connecting hundreds of billions of devices and things in the 6G era. For these reasons, 6G communication systems are referred to as "beyond 5G" systems.

[0003] The 6G communication system, expected to be realized around 2030, will have a maximum transmission rate of 1,000 gigabits per second at the terahertz level and a wireless latency of 100 microseconds, making it 50 times faster than the 5G communication system and with a wireless latency of 1 / 10 of that of the 5G communication system.

[0004] To achieve such high data transmission rates and ultra-low latency, 6G communication systems have been considered for implementation in the terahertz band (e.g., the 95 GHz to 3 THz band). It is anticipated that technologies capable of ensuring signal transmission distance (i.e., coverage) will become even more critical, as path loss and atmospheric absorption in the terahertz band are more severe than those in the millimeter-wave band introduced in 5G. As a primary technology for ensuring coverage, it is necessary to develop multi-antenna transmission technologies, including radio frequency (RF) components, antennas, novel waveforms with better coverage than OFDM, beamforming and massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, and massive MIMO. Furthermore, new technologies to improve terahertz band signal coverage are being discussed, such as metamaterial-based lenses and antennas, orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS).

[0005] Furthermore, to improve frequency efficiency and system networks, the following technologies have been developed for 6G communication systems: full-duplex technology to enable uplink (UE transmission) and downlink (Node B transmission) to use the same frequency resources simultaneously; network technologies that utilize satellites, High Altitude Platform Stations (HAPS), etc., in an integrated manner; network architecture innovation technologies to support mobile Node Bs and achieve network operation optimization and automation; dynamic spectrum sharing technology based on spectrum usage prediction to avoid conflicts; artificial intelligence (AI)-based communication technologies to achieve system optimization by using AI from the technology design process and internalizing end-to-end AI support functions; and next-generation distributed computing technologies to achieve services with complexity exceeding the computing power limits of UEs by using ultra-high-performance communication and computing resources (Mobile Edge Computing (MEC), cloud, etc.). In addition, efforts are being made to further enhance connectivity between devices, further optimize networks, promote the software implementation of network entities, increase the openness of wireless communication, develop mechanisms for achieving hardware-based secure environments and secure data use, and develop technologies for privacy maintenance methods by designing new protocols for 6G communication systems.

[0006] The research and development of 6G communication systems is expected to enable the next level of hyper-connectivity in a new dimension through hyper-connectivity that covers connections between things and between people and things. In particular, services such as truly immersive XR, high-fidelity mobile holograms, and digital replicas are expected to be available through 6G communication systems. Furthermore, services such as remote surgery, industrial automation, and emergency response will be provided via 6G communication systems by enhancing security and reliability, thus enabling the application of these services in various fields such as industry, healthcare, automotive, and home appliances.

[0007] Meanwhile, research on 6G communication systems or next-generation wireless communication systems, as described above, pays particular attention to beamforming technology and methods to enable beamforming technology to operate more effectively, as a way to address the problem of reduced base station coverage and the resulting degradation of communication service quality that may occur during signal transmission / reception in millimeter wave and terahertz bands or higher ultra-high frequency bands. Summary of the Invention

[0008] Technical issues

[0009] As described above, in the 6G communication system or next-generation wireless communication system to which this disclosure can be applied, signal transmission / reception in millimeter wave and terahertz (THz) bands or even higher ultra-high frequency bands is considered to ensure higher signal transmission rates. On the other hand, with the use of higher frequency bands, the degree of signal attenuation with distance increases, so a reduction in base station coverage due to signal attenuation is inevitable. To address this coverage reduction problem, in the 6G communication system or next-generation wireless communication system to which this disclosure can be applied, beamforming technology can be considered to amplify signal strength for signal transmission / reception between the terminal and the base station. However, even when signal transmission / reception is performed between the terminal and the base station based on beamforming technology, the signal strength amplification effect of beamforming technology may rapidly attenuate due to changes in the surrounding communication environment (such as the movement of the terminal). That is, in the ultra-high frequency band, beamforming technology may not operate effectively depending on the communication environment. Furthermore, beamforming technology may not operate effectively because it may be difficult to select appropriate beams in communication environments using a large number of beams. Therefore, in 6G communication systems or next-generation wireless communication systems to which this disclosure can be applied, there is a need to design a beam tracking (or beam management) method that can determine the beam with optimal performance, continuously track beam changes, and exchange information about beam status between the terminal and the base station in order to perform more stable and efficient operation of beamforming technology.

[0010] Technical solution

[0011] To address the aforementioned problems, according to embodiments of this disclosure, a method executed by a terminal in a communication system is provided. The method includes: receiving a message including cluster information from a first base station; identifying whether a cluster corresponding to the terminal's location has changed based on the cluster information and the terminal's location information; and, if the cluster has changed, sending a channel state information (CSI) report to the first base station including information about the changed cluster, wherein the cluster information includes information about at least one cluster identified based on a location-specific beam pattern, and wherein the location-specific beam pattern is identified based on information about an optimal beam and location information of each of a plurality of terminals served by the first base station.

[0012] Furthermore, according to embodiments of this disclosure, a method performed by a first base station in a communication system is provided. The method includes: sending a message including clustering information to a terminal; receiving a channel state information (CSI) report from the terminal including information about the changed clustering if the clustering corresponding to the location of the terminal is changed; identifying at least one beam corresponding to a channel state information reference signal (CSI-RS) based on the information about the changed clustering; and sending the CSI-RS to the terminal based on the identified at least one beam, wherein the clustering information includes information about at least one cluster identified based on a location-specific beam pattern, and wherein the location-specific beam pattern is identified based on information about an optimal beam and location information of each of a plurality of terminals served by the first base station.

[0013] Furthermore, according to embodiments of this disclosure, a terminal for a communication system is provided. The terminal includes: a transceiver; and a controller connected to the transceiver and configured to: receive a message including clustering information from a first base station; identify whether a cluster corresponding to the terminal's location has changed based on the clustering information and the terminal's location information; and, in the case of a cluster change, send a channel state information (CSI) report to the first base station including information about the changed cluster, wherein the clustering information includes information about at least one cluster identified based on a location-specific beam pattern, and wherein the location-specific beam pattern is identified based on information about an optimal beam and location information of each of a plurality of terminals served by the first base station.

[0014] Furthermore, according to embodiments of this disclosure, a first base station for a communication system is provided. The first base station includes: a transceiver; and a controller connected to the transceiver and configured to: send a message including clustering information to a terminal; receive a channel state information (CSI) report from the terminal including information about the changed clustering if the clustering corresponding to the location of the terminal is changed; identify at least one beam corresponding to a channel state information reference signal (CSI-RS) based on the information about the changed clustering; and send the CSI-RS to the terminal based on the identified at least one beam, wherein the clustering information includes information about at least one cluster identified based on a location-specific beam pattern, and wherein the location-specific beam pattern is identified based on information about an optimal beam and location information of each of a plurality of terminals served by the first base station.

[0015] Beneficial effects

[0016] According to this disclosure, a method is provided for managing the beams of each cluster by clustering location-specific beam patterns by a base station and sharing the clustering results with a terminal. Therefore, the base station can, based on the beam pattern corresponding to the cluster to which the terminal's location belongs, match (or map) the beams that are most likely selected as the best beams for execution to a channel state information reference signal (CSI-RS), and send the CSI-RS to the terminal, thereby achieving improved beam tracking performance.

[0017] Furthermore, according to the embodiments proposed in this disclosure, beam management can be performed on each cluster, thus enabling faster determination of high-performance beams for signal transmission and reception, even in communications using a large number of beams (e.g., terahertz (THz) communications, vehicle communications, or RIS-based communications).

[0018] The beneficial effects that can be obtained from this disclosure may not be limited to those described above, and other effects not mentioned will be clearly understood by those skilled in the art to which this disclosure pertains from the following description. Attached Figure Description

[0019] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments thereof with reference to the accompanying drawings:

[0020] Figure 1 The structure of a new radio (NR or 5G) system according to this disclosure is shown;

[0021] Figure 2 The structure of a next-generation wireless communication system according to this disclosure is shown;

[0022] Figure 3 The diagram illustrates the structure of a system in which a terminal and a base station transmit or receive signals based on beamforming technology in a next-generation wireless communication system according to the present disclosure;

[0023] Figure 4A This illustrates the process of downlink transmission beam adjustment performed by a terminal and base station according to this disclosure;

[0024] Figure 4B This illustrates the process of downlink receive beam adjustment performed by a terminal and base station according to this disclosure;

[0025] Figure 5 A beam indication method in a next-generation wireless communication system according to the present disclosure is shown;

[0026] Figure 6 The process of performing beam tracking according to an embodiment of the present disclosure is illustrated;

[0027] Figure 7 The process of performing beam tracking according to an embodiment of the present disclosure is illustrated;

[0028] Figure 8 An example is shown of determining the beam corresponding to CSI-RS in beam tracking according to an embodiment of the present disclosure;

[0029] Figure 9 An example is shown of determining the beam corresponding to CSI-RS in beam tracking according to an embodiment of the present disclosure;

[0030] Figure 10A Examples of methods for clustering location-specific beam patterns by a base station according to embodiments of the present disclosure are shown;

[0031] Figure 10B Examples of methods for clustering location-specific beam patterns by a base station according to embodiments of the present disclosure are shown;

[0032] Figure 11 The present disclosure illustrates a processing sequence in which a terminal sends location information and information about the optimal beam at the corresponding location to a base station, according to an embodiment of the present disclosure.

[0033] Figure 12 This illustration shows an embodiment of the present disclosure in which a terminal transmits a list of signal strength measurement results of a reference signal to a base station and a processing sequence of information about the optimal beam at the corresponding location;

[0034] Figure 13 The present disclosure illustrates an embodiment in which a base station identifies a location-specific beam pattern based on the location information of a terminal and information about the optimal beam, and performs a processing sequence for clustering the beam patterns.

[0035] Figure 14 The overall flow of the process for a base station to acquire clustering information according to an embodiment of the present disclosure is shown;

[0036] Figure 15 The present disclosure illustrates an embodiment in which a terminal performs a beam tracking processing sequence based on location information and clustering information received from a base station;

[0037] Figure 16 The diagram illustrates a sequence of processing steps for a base station to change the beam corresponding to CSI-RS according to an embodiment of the present disclosure;

[0038] Figure 17 The overall process of a terminal and base station performing beam tracking based on clustering information according to embodiments of the present disclosure is illustrated.

[0039] Figure 18 The structure of a terminal according to an embodiment of the present disclosure is shown; and

[0040] Figure 19The structure of a base station according to an embodiment of the present disclosure is shown. Detailed Implementation

[0041] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0042] In describing embodiments of this disclosure, descriptions relating to technical content known in the art and not directly related to this disclosure will be omitted.

[0043] This omission of unnecessary descriptions is to prevent confusion with the main idea of ​​this disclosure and to more clearly convey the main idea.

[0044] For the same reason, some elements may be exaggerated, omitted, or shown schematically in the accompanying drawings. Furthermore, the dimensions of each element do not perfectly reflect the actual dimensions. Identical or corresponding elements are provided with the same reference numerals in the drawings.

[0045] The advantages and features of this disclosure, as well as the ways in which they are implemented, will become apparent from the following detailed description of embodiments in conjunction with the accompanying drawings.

[0046] However, this disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. The following embodiments are provided only to fully disclose this disclosure and to inform those skilled in the art of its scope, and this disclosure is defined only by the scope of the appended claims. Throughout this specification, the same or similar reference numerals denote the same or similar elements.

[0047] Here it will be understood that each block of the flowchart illustration, and combinations of blocks in the flowchart illustration, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, executable by the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart blocks. These computer program instructions can also be stored in a computer-usable or computer-readable storage medium, and can instruct the computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-usable or computer-readable storage medium produce an article of manufacture including instruction means for implementing the functions specified in one or more flowchart blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing steps for implementing the functions specified in one or more flowchart blocks.

[0048] Furthermore, each block in a flowchart can represent a module, segment, or section of code, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions specified in a block may occur out of order. For example, two blocks shown consecutively may, in fact, execute substantially simultaneously, or these blocks may sometimes execute in reverse order, depending on the functions involved.

[0049] As used in embodiments of this disclosure, "unit" refers to a software or hardware element that performs a predetermined function, such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC). However, the meaning of "unit" is not always limited to software or hardware. A "unit" may be configured to be stored in an addressable storage medium or to execute one or more processors. Thus, a "unit" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by a "unit" may be combined into a smaller number of elements, or may be combined into a "unit," or may be divided into a larger number of elements or "units." Furthermore, these elements and "units" may be implemented as replicating one or more CPUs within a device or secure multimedia card.

[0050] In the following description, for ease of description, some terms and names defined in the 3GPP standards (standards for 5G, NR, LTE, or similar systems) may be used. Additionally, newly defined terms and names may be used in next-generation communication systems (e.g., systems other than 6G or 5G) to which this disclosure is applicable or adopted in existing communication systems. The use of terms and names is not limited to those of this disclosure, and this disclosure can be applied in the same manner to systems conforming to other standards and can be modified to other forms without departing from the technical spirit of this disclosure.

[0051] In embodiments of this disclosure, it should be understood that the singular forms “a,” “one,” and “the” include plural references unless the context clearly specifies otherwise.

[0052] In embodiments of this disclosure, ordinal terms, such as the expressions “first” and “second”, may be used to describe various elements, but the corresponding elements should not be limited by these terms. These terms are used only to distinguish one element from any other element. For example, without departing from the scope of this disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0053] In embodiments of this disclosure, the term "and / or" includes any one of any combination of the listed plurality of related items.

[0054] The terminology used in this disclosure is for describing particular embodiments only and is not intended to limit the disclosure. Singular expressions may include plural expressions unless they are clearly distinct in the context. As used herein, the expressions “comprising” or “having” are intended to specify the presence of the mentioned features, numbers, steps, operations, elements, components or combinations thereof, and should be construed as not excluding the possibility of one or more other features, numbers, steps, operations, elements, components or combinations thereof being present or added.

[0055] As used in embodiments of this disclosure, the phrases “associated with” and “associated with” and their derivatives may mean including, being included, interconnected with, containing, being contained, connected to or connected with, coupled to or connected with, able to communicate with, cooperate with, intertwine, juxtapose, proximate, bound to or having, etc.

[0056] As used in this disclosure, the expressions "greater than" or "less than" are used to determine whether a specific condition is met or achieved, but this is for illustrative purposes only and does not exclude "greater than or equal to" or "equal to or less than". A condition represented by the expression "greater than or equal to" can be replaced by a condition represented by "greater than", a condition represented by the expression "equal to or less than" can be replaced by a condition represented by "less than", and a condition represented by "greater than and equal to or less than" can be replaced by a condition represented by "greater than and less than".

[0057] Before providing a detailed description of this disclosure, examples of interpretable meanings for some terms used herein are given below. However, it should be noted that these terms are not limited to the examples of interpretable meanings given below.

[0058] In this disclosure, a terminal (or communication terminal) is an entity that communicates with a base station or any other terminal, and may be referred to as a node, user equipment (UE), next-generation UE (NG UE), mobile station (MS), device, terminal, etc. A terminal may include at least one of a smartphone, tablet PC, mobile phone, video phone, e-book reader, desktop PC, laptop PC, netbook computer, personal digital assistant (PDA), portable multimedia player (PMP), MP3 player, medical device, camera, and wearable device. Furthermore, a terminal may include at least one of a television, digital video disc (DVD) player, audio equipment, refrigerator, air conditioner, vacuum cleaner, oven, microwave oven, washing machine, air purifier, set-top box, home automation control panel, security control panel, media box, game console, electronic dictionary, electronic key, camera, and electronic photo frame. Furthermore, the terminal may include at least one of various medical devices (e.g., various portable medical measurement devices (blood glucose monitoring devices, heart rate monitoring devices, blood pressure measuring devices, body temperature measuring devices, etc.), magnetic resonance angiography (MRA), magnetic resonance imaging (MRI), computed tomography (CT) scanners, ultrasound machines, etc.), navigation devices, global positioning system (GPS) receivers, event data loggers (EDR), flight data loggers (FDR), vehicle infotainment devices, marine electronic equipment (e.g., marine navigation devices, gyrocompasses, etc.), avionics equipment, security equipment, automotive mainframes, home or industrial robots, drones, bank automatic teller machines (ATMs), point of sale (POS) devices in stores, or Internet of Things (IoT) devices (e.g., light bulbs, various sensors, electricity or gas meters, sprinkler systems, fire alarms, thermostats, streetlights, toasters, sporting goods, hot water tanks, heaters, boilers, etc.). However, this disclosure is not limited to the examples above, and the term "terminal" may also be used to refer to a device with the same or similar meaning.

[0059] In this disclosure, a base station is an entity that communicates with and allocates resources to a terminal, and may be referred to as a base station (BS), node B (NB), next-generation radio access network (NG RAN), access point (AP), transmit / receive point (TRP), radio access unit, base station controller, node on a network, etc. Alternatively, depending on functional division, a base station may be referred to as a central unit (CU) or a distributed unit (DU). However, this disclosure is not limited to the examples above, and base stations may also be referred to by terms with the same or similar meanings.

[0060] In this disclosure, the term "high-level message" may be referred to as "high-level signal," "high-level signaling," "upper-level signaling," or "radio resource control (RRC) message," and this disclosure is not limited thereto. The term may also be referred to by other terms having the same or similar meaning.

[0061] Furthermore, in embodiments of this disclosure, the optimal beam (one or more optimal beams) may refer to two beams in a beam pair (or multiple beam pairs) configured by beams on the transmitter side or receiver side, wherein the two beams are configured by one beam on the transmitter side and one beam on the receiver side, and are measured to have the best performance among the beams available on the transmitter side and receiver side. That is, according to embodiments of this disclosure, the optimal beam may refer to the best transmit beam on the transmitter side or the best receive beam on the receiver side. Meanwhile, in this disclosure, a beam with good performance may refer to a beam whose received signal strength (e.g., Reference Signal Received Power (RSRP)) is equal to or greater than a predetermined threshold, or whose channel quality is good. Furthermore, in embodiments of this disclosure, the optimal beam may generally refer to the transmit beam with the best performance used by the base station to communicate with the terminal within the optimal beam pair measured according to the reference signal transmitted by the base station, or it may refer to the top N beams in terms of performance. Moreover, this disclosure is not limited thereto, and various examples of optimal beams described in embodiments of this disclosure may be referenced.

[0062] Figure 1 The structure of a new radio (NR or 5G) system according to this disclosure is shown.

[0063] refer to Figure 1 As shown in the figure, the radio access network of the NR system can include NR base stations (new radio nodes B or NR gNB) 1-10 and NR core network 1-05. NR terminals (or NR UEs) 1-15 can access external networks through NR gNB 1-10 and NR core network 1-05.

[0064] exist Figure 1In the NR system, NR gNB 1-10 corresponds to the evolved Node B (eNB) of a traditional LTE system. The NR gNB can connect to NR UE 1-15 via radio channels and can provide better service than a traditional Node B. Since all user services are served through shared channels in the NR system, equipment is needed to collect and schedule UE buffer states, available transmission power states, and channel states; NR gNB 1-10 performs these functions. One NR gNB typically controls multiple cells. In the NR system, to achieve ultra-high-speed data transmission compared to LTE systems, data transmission / reception can be performed based on bandwidth equal to or wider than the traditional maximum bandwidth, and Orthogonal Frequency Division Multiplexing (OFDM) can be applied as the radio access technology. Furthermore, modulation schemes and Adaptive Modulation and Coding (AMC) schemes are applied based on the UE's channel states to determine the channel coding rate. The NR core network 1-05 can perform functions such as supporting mobility, configuring bearers, and configuring QoS. The NR core network is the equipment used to perform functions for managing UE mobility and various control functions, and can connect to multiple gNBs. Furthermore, the NR system can link to a legacy LTE system, and the NR core network 1-05 can connect to the Mobility Management Entity (MME) 1-25 via a network interface. MME 1-25 can connect to the LTE eNB 1-30, which serves as a base station for the LTE system.

[0065] Simultaneously, in the NR system according to this disclosure, blind decoding is performed in specific time and frequency domains to receive the PDCCH including DCI. The base station can configure control resource sets (CORESETs) and search spaces in the terminal via upper-layer messages to provide the terminal with time and frequency domains, as well as mapping methods for performing blind decoding. The base station can configure up to 3 CORESETs and up to 10 search spaces for each bandwidth portion (BWP) configured in the terminal. For example, the base station and the terminal can send and receive signaling information as shown in [Table 1] below to transmit information on the CORESETs.

[0066] [Table 1]

[0067]

[0068] The ControlResourceSet signaling information includes information about each CORESET. The information included in the ControlResourceSet signaling information can have the following meanings.

[0069] -controlResourceSetId: Indicates the CORESET index.

[0070] -Frequency Domain Resources: Represents the frequency resource information for the CORESET. For all PRBs included in the BWP, each RB group is created, consisting of 6 RBs, and whether each RB group is included in the CORESET frequency resources is indicated by 1 bit. (1: included in the CORESET, 0: not included in the CORESET)

[0071] -duration: Symbol-level time resource information for CORESET. This information has a value of 1, 2, or 3.

[0072] -cce-REG-MappingType: Indicates whether the control channel element (CCE) mapped to the CORESET is interleaved. If the CCE is interleaved, additional information related to interleaving is provided (reg-BundleSize, interleaarSize, and shiftIndex).

[0073] -precoderGranularity: Represents precoding-related information for the frequency resources of the CORESET. The size of the precoder can be the same as the Resource Element Group (REG) beam size or the size of all frequency resources in the CORESET.

[0074] -tci-StatePDCCH-ToAddList,tci-StatePDCCH-ToReleaseList: Represents the set of active Transport Configuration Indicator (TCI) states for CORESET. One of the active TCI states for CORESET can be activated via L1 signaling (e.g., DCI) or L2 signaling (e.g., MAC CE). If CORESET is configured during initial access processing, the TCI state set may not be configured. A description of the TCI states will be given later.

[0075] -tci-PresentInDCI: Indicates whether the indicator of the TCI status of the PDSCH is included in the DCI sent via the PDCCH included in the CORESET.

[0076] -Pdcch-DMRS-ScramblingID: The sequence scrambling index of the DMRS transmitted in the PDCCH included in the CORESET.

[0077] The terminal can perform blind decoding for receiving PDCCH by referring to the information related to CORESET mentioned above.

[0078] In the NR according to this disclosure, the base station can transmit information to the terminal regarding the quasi-co-address (QCL) relationship between antenna ports that transmit downlink channels (e.g., DMRS port of PDSCH, DMRS port of PDCCH, or CSI-RS port of CSI-RS), enabling the terminal to smoothly receive and decode downlink channels (e.g., PDCCH or PDSCH). The QCL relationship between antenna ports can have one of a total of four QCL types.

[0079] - "QCL-typeA": {Doppler frequency shift, Doppler spread, average delay, delay spread}

[0080] - "QCL-typeB": {Doppler frequency shift, Doppler spread}

[0081] - "QCL-typeB": {Doppler frequency shift, average delay}

[0082] - "QCL-typeD": {Space RX parameter}

[0083] If two different antenna ports share a portion of the QCL type described above, or if one antenna port refers to a portion of the QCL type of another antenna port, then the terminal may assume that the two antenna ports share the parameters supported in the QCL type, which are shared or referenced by both antenna ports, and therefore have the same value.

[0084] The base station can configure TCI status to transmit information related to the QCL relationship between antenna ports to the terminal. TCI status includes information related to one or two downlink RSs and supported QCL types. For example, the base station and the terminal can exchange signaling information as shown in [Table 2] below to transmit information related to TCI status.

[0085] [Table 2]

[0086]

[0087] The “TCI-state” included in the signaling information contains information related to each TCI state. According to the signaling information, each TCI state includes information related to the TCI state index and one or two types of QCL-Info (qcl-Type1 and qcl-Type2). qcl-Type1 or qcl-Type2 provides an index of the cell in which the RS is configured, including an index of the BWP of the RS, an RS providing information related to the parameters supported in the QCL type according to the QCL type, and information related to one of the four QCL types in total. Of the four QCL types, qcl-Type1 can have one of the QCL types “QCL-typeA”, “QCL-typeB”, or “QCL-typeC”, and qcl-Type2 can have “QCL-typeD”. By referencing the active TCI state of the antenna port transmitting the downlink channel, the terminal can receive and decode the downlink channel based on the RS referenced in the active TCI state and the QCL types supported therein.

[0088] This disclosure provides a CSI framework for indicative channel state information (CSI) measurements by a base station and for reporting to a terminal. The CSI framework of an NR system can be configured with at least two elements, including resource settings and reporting settings. The reporting settings can be associated with the resource settings by referencing at least one ID of the resource settings.

[0089] In this disclosure, resource settings may include information relating to a reference signal (RS) used by the terminal to measure channel state information. The base station may configure at least one resource setting for the terminal. For example, the base station and the terminal may exchange signaling information as shown in [Table 3] below to transmit information relating to the resource settings.

[0090] [Table 3]

[0091]

[0092] The signaling information CSI-ResourceConfig may include information related to each resource setting. Based on the signaling information, each resource setting may include a resource setting index (csi-ResourceConfigId), a BWP index (bwp-ID), a resource's time-domain transmission configuration (resourceType), or a resource set list (csi-RS-ResourceSetList) including at least one resource set. The resource's time-domain transmission configuration can be configured for aperiodic, semi-persistent, or periodic transmission. The resource set list may be a collection of resource sets used for channel measurements or a collection of resource sets used for interference measurements. If the resource set list is a collection of resource sets used for channel measurements, each resource set may include at least one resource, and at least one source may correspond to an index of a CSI Reference Signal (CSI-RS) resource or a Synchronization / Broadcast Channel Block (SS / PBCH Block, SSB). If the resource set list is a collection of resource sets used for interference measurements, each resource set may include at least one interference measurement resource (CSI Interference Measurement, CSI-IM). For example, if the resource set includes CSI-RS, the base station and the terminal can exchange signaling information as shown in Table 4 below to transmit information related to the resource set.

[0093] [Table 4]

[0094]

[0095] The signaling information NZP-CSI-RS-ResourceSet includes information associated with each resource set. According to the signaling information, each resource set may include at least information related to the resource set index (nzp-CSI-ResourceSetId) and / or the CSI-RS index (or identifier) ​​set (nzp-CSI-RS-Resources). Furthermore, each resource set may include a portion of information (repeated) related to the spatial domain transmission filters of the CSI-RS resources, and / or a portion of information related to whether the CSI-RS resources are for tracking purposes (trs-Info).

[0096] CSI-RS can be the most representative reference signal included in the resource set. The base station and the terminal can exchange signaling information as shown in Table 5 below to transmit information related to the CSI-RS resources.

[0097] [Table 5]

[0098]

[0099] The signaling information NZP-CSI-RS-Resource includes information related to each CSI-RS. The information included in the signaling information NZP-CSI-RS-Resource can have the following meanings.

[0100] -nzp-CSI-RS-ResourceId: Index of CSI-RS resources.

[0101] -resourceMapping: Resource mapping information for CSI-RS resources.

[0102] -powerControlOffset: The ratio between PDSCH EPRE (energy per RE) and CSI-RS EPRE.

[0103] -powerControlOffsetSS: The ratio between SS / PBCH block EPRE and CSI-RS EPRE.

[0104] -scramblingID: The scrambling index of the CSI-RS sequence.

[0105] -periodicityAndOffset: Transmission period and slot offset of CSI-RS resources

[0106] -qcl-InfoPeriodicCSI-RS: TCI status information when the corresponding CSI-RS is a periodic CSI-RS.

[0107] The “resourceMapping” included in the signaling information NZP-CSI-RS-Resource indicates the resource mapping information of CSI-RS resources. This resource mapping information can include resource element (RE) mappings, number of ports, symbol mappings, CDM types, frequency resource densities, and band mappings for frequency resources. Each of the port number, frequency resource density, CDM type, and time-frequency domain RE mappings, which can be configured through the resource mapping information, can have a defined value in one of the rows shown in [Table 6].

[0108] [Table 6]

[0109]

[0110] [Table 6] shows the number of CSI-RS ports (X), CDM type, frequency of CSI-RS component RE mode, and time-domain start position. The frequency resource density is configurable by the number (k') of frequency-domain REs and the number (l') of time-domain REs in the CSI-RS component RE mode. The aforementioned CSI-RS component RE mode can be the basic unit for configuring CSI-RS resources. A CSI-RS component RE mode can be configured with YZ REs using Y = 1 + max(k') of frequency-domain resource elements REs and Z = 1 + max(l') of time-domain REs. If the number of CSI-RS ports is 1, the location of the CSI-RS REs can be specified in the Physical Resource Block (PRB) without being limited by subcarriers, and can be specified by a 12-bit bitmap. If the number of CSI-RS ports is {2, 4, 8, 12, 16, 24, 32} and Y equals 2, the location of the CSI-RS REs can be specified at every two subcarriers in the PRB, and can be specified by a 6-bit bitmap. If the number of CSI-RS ports is 4 and Y equals 4, the location of the CSI-RS RE can be specified at every four subcarriers in the PRB, and this can be specified by a bitmap with 3 bits. Similarly, the location of the time-domain RE can be specified by a bitmap with a total of 14 bits. The length of the bitmap can be changed in the same way as the frequency location specification, depending on the Z values ​​shown in [Table 6]. However, the principle of change is similar to that described above, so repeated descriptions will be omitted below.

[0111] Figure 2 The structure of a next-generation wireless communication system according to this disclosure is shown.

[0112] refer to Figure 2 As shown in the figure, the next-generation wireless communication system to which this disclosure applies may include a next-generation base station 2-10 and a next-generation core network (CN) 2-05. Terminal 2-15 can access external networks through the next-generation base station 2-10 and the next-generation CN 2-05.

[0113] exist Figure 2 In this context, next-generation base stations 2-10 can correspond to Evolved Node B (eNB) in a traditional LTE system, or perform operations similar to... Figure 1The role corresponding to the NR base station (gNB) in the NR system described herein. Alternatively, in embodiments of this disclosure, the next-generation base station 2-10 may refer to an LTE eNB or an NR gNB. The next-generation base station 2-10 can connect to the terminal 2-15 via a radio channel and provide communication services superior to those of a traditional Node B. In next-generation wireless communication systems, since user services are served through a shared channel, a device is needed for collecting and scheduling state information of the UE's buffer state, available transmission power state, and channel state, and the next-generation gNB 2-10 can perform the above functions. One next-generation gNB 2-10 typically controls multiple cells. To achieve ultra-high-speed data transmission compared to traditional wireless communication systems, the next-generation system 2-10 can provide services based on a bandwidth equal to or wider than the traditional maximum bandwidth, and can use newly adopted radio access technologies or radio access technologies based on orthogonal frequency division multiplexing (OFDM). Furthermore, modulation schemes with determined channel coding rates and adaptive modulation and coding (AMC) schemes can be used according to the UE's channel state. The next-generation CN 2-05 can perform functions supporting mobility, configuring bearers, configuring QoS, etc. The next-generation CN 2-05 is a device for performing functions and various control functions for managing the mobility of UE 2-15, and can be connected to multiple base stations. Furthermore, the next-generation wireless communication system to which this disclosure applies can be linked to a legacy LTE or NR system, and when interoperating with an LTE system, the next-generation CN can be connected to a Mobility Management Entity (MME) 2-25 via a network interface. The MME can be connected to an eNB 2-30, which acts as a legacy LTE base station. Alternatively, when interoperating with an NR system, the next-generation CN can be connected to an NR core network 2-25 via a network interface. The NR core network 2-25 can be connected to an NR gNB 2-30. Meanwhile, in the next-generation wireless communication system according to this disclosure, configuration and reference can be performed in the terminal. Figure 1 The signaling information described in Tables 1 through 6 is the same or similar.

[0114] Meanwhile, in the aforementioned next-generation wireless communication systems, it is possible to implement systems supporting large physical areas within a single base station that includes multiple Transmit / Receive Points (TRPs) capable of transmitting or receiving, thereby improving latency caused by frequent terminal information exchange and effectively utilizing radio resources. For example, such systems could include: a Distributed Antenna System (DAS), which transmits or receives the same signal by implementing different TRPs in a single base station with physical antennas; a Remote Radio Header System (RRH system), which implements different TRPs in a single base station with a structure including antennas and radio frequency (RF) terminals capable of transmitting or receiving different signals; or a Cooperative Multipoint Transmit / Receive System (CoMP system), which allows different TRPs in one or more base stations to simultaneously synchronize and transmit and receive the same information to and from a single terminal (or user) (coherent), or for each TRP to independently transmit / receive information from a terminal (incoherent).

[0115] On the other hand, with the emergence of various connected devices such as smartphones, user data usage is growing exponentially, further increasing the demand for such data. Therefore, in next-generation wireless communication systems to which this disclosure can be applied, a method is being considered for transmitting signals using a frequency band wider than that of conventional wireless communication systems. For example, methods are being considered for increasing signal transmission rates using 28 GHz, 60 GHz, terahertz (THz) bands, or higher. However, since signal attenuation increases with distance as higher frequency bands are used, a reduction in base station coverage due to signal attenuation is unavoidable when using the aforementioned ultra-high frequencies as the center frequency. To address this coverage reduction problem of base stations in next-generation wireless communication systems to which this disclosure can be applied, a method for operating beamforming technology is provided, which enables dense signal transmission in a specific direction when base stations and terminals transmit / receive signals, thereby amplifying the strength of the transmitted / received signals.

[0116] Beamforming techniques that can be considered in next-generation wireless communication systems to which this disclosure applies can be summarized as follows.

[0117] A. Simulated beamforming

[0118] -Analog beamforming is a method that uses multiple array antennas and overlapping antenna radiation patterns to transmit different transmission powers and phases in order to physically form a directional beam in a specific direction and obtain antenna gain.

[0119] - In the absence of channel information for the desired target receiver, beams can be configured from multiple antennas in the desired direction, and transmission / reception can only occur in one direction at a time. (That is, radiation patterns in other directions can be canceled out.)

[0120] - When using multiple antennas, it is possible to form beams with high linearity and therefore reach farther distances with the same power and high antenna gain. (That is, beamforming can be performed by varying the beamwidth or length depending on the number of antennas.)

[0121] - The beam formed by the simulated beamforming method has a long length, but it can only support a narrow area.

[0122] B. Digital Beamforming

[0123] Digital beamforming is a method for forming multiple orthogonal beams by utilizing multi-channel information between antennas with different intensities in a multi-antenna transmit / receive environment, and by applying different codes to each antenna before transmission to eliminate desired inter-channel interference.

[0124] - By applying precoding to the data transmitted through each antenna, the different channel characteristics can be maximized.

[0125] - It can support single-user MIMO and multi-user MIMO.

[0126] C. Hybrid Beamforming

[0127] Hybrid beamforming is a method that uses both analog beamforming and digital beamforming simultaneously.

[0128] This is a method of using digital beamforming, relative to the transmit antennas and beams formed by analog beamforming methods, by using different precoding techniques for each antenna.

[0129] D. Newly introduced beamforming

[0130] In addition to the analog beamforming, digital beamforming, and hybrid beamforming methods described above, combinations of these methods or new beamforming methods can be introduced into next-generation wireless communication systems to which this disclosure can be applied. In this case, terminals and base stations can transmit or receive signals based on beams formed by the newly introduced beamforming methods.

[0131] In this disclosure, beamforming technology can refer to at least one of analog beamforming, digital beamforming, and hybrid beamforming, or a technology that uses a beam formed by a newly introduced beamforming method and beamforming. It can also refer to a method of occupying and transmitting resources that can be physically distinguished or distinguishable by frequency, time, code, etc., for transmitting signals (or data and information). In this context, embodiments of this disclosure are applicable to all communication systems, where the corresponding occupied resources are referred to as beams. Reference will be made to... Figure 3Describe in detail the system architecture of terminals and base stations that transmit or receive signals based on the aforementioned beamforming technology.

[0132] Figure 3 The diagram illustrates the structure of a system in which terminals and base stations transmit or receive signals based on beamforming technology in a next-generation wireless communication system according to this disclosure.

[0133] refer to Figure 3 , Figure 3 A system is illustrated in which, to improve the efficiency of beamforming technology, not only the transmit beam of a transmitter (in the case of downlink, the transmitter may correspond to a base station according to this disclosure, and in the case of uplink, the transmitter may correspond to a terminal according to the invention) is used, but also the receive beam of a receiver (in the case of downlink, the receiver may correspond to a terminal according to this disclosure, and in the case of uplink, the receiver may correspond to a base station according to the invention). In this case, the directions of the transmit beam and the receive beam should be synchronized (or aligned) with each other to achieve the effect of amplifying signal strength through beamforming technology. Even if the terminal is located in the direction of the base station's transmit beam, if the direction of the terminal's receive beam is not synchronized (misaligned) with the direction of the transmit beam, the terminal may not be able to correctly receive the signal transmitted from the base station through the transmit beam, and therefore the received signal strength may be weak. Therefore, in order for the terminal and base station to transmit and receive signals more efficiently based on beamforming technology using transmit and receive beams, the directions of the transmit and receive beams are synchronized with each other (indicated by reference numeral 320), or when the direct path between the base station and the terminal is blocked by obstacles in the surrounding environment, it is necessary to perform beam management to determine and maintain a transmit / receive beam pair 330 that is not perfectly synchronized but has optimal performance according to the reflection path. If such beam management can be operated effectively, the effect of improving data transmission rate and throughput can be obtained. On the other hand, the above-mentioned beam management can be distinguished depending on whether the terminal is performing an initial access procedure or whether the terminal and the base station have already established a connection, and each case will be described in detail below.

[0134] First, beam management during the initial access procedure can refer to the process of determining the initial beam pair. The base station can transmit a synchronization signal block (SS / PBCH block, or SSB) corresponding to each downlink transmit beam during the terminal's initial access procedure by using different downlink transmit beams. The terminal can measure the SSB corresponding to each downlink transmit beam of the base station by alternating its own receive beams and select the optimal beam based on the measurement results. Subsequently, the terminal can transmit a random access preamble to the base station based on information about the preamble and the physical random access channel (PRACH) timing corresponding to the selected optimal beam. The base station can identify the optimal beam based on the occurrence of the physical random access channel (PRACH) for transmitting the random access preamble, and based on the identified optimal beam, the base station can send a random access response (RAR) to the terminal to perform the process of determining the initial beam pair.

[0135] Furthermore, even after the initial transmit / receive beam pair (initial optimal beam or initial optimal beam pair) for signal transmission / reception between the terminal and the base station has been determined (that is, even after the initial access process of the terminal is completed and the connection between the terminal and the base station is established), beam management can be performed in cases where the optimal beam for a corresponding time point needs to be identified due to the movement or rotation of the terminal. Alternatively, even if the terminal is fixed, beam management can be performed in cases where the channel state of the predetermined beam pair changes due to the movement of another object in the vicinity to block the beam or receive a blocked beam, requiring the identification of the optimal beam for a corresponding time point. For this purpose, beam management can be referred to as beam adjustment (or beam refinement). Beam adjustment can include beam adjustment performed by the downlink transmitting side and beam adjustment performed by the downlink receiving side. In the following text, reference will be made to... Figures 4A to 4B Detailed description of beam adjustment according to this disclosure.

[0136] Figure 4A This illustrates the process of downlink transmission beam adjustment performed by a terminal and base station according to this disclosure.

[0137] refer to Figure 4A When beam adjustment is performed by the downlink transmitting side, the receiving beam 450 of the terminal 400 can be maintained, and the transmitting beam of the base station 410 can be adjusted. For this purpose, the base station 410 can transmit signals by alternately, sequentially, or randomly using different transmitting beams. Furthermore, in this disclosure, alternately, sequentially, or randomly using different beams (transmitting beams or receiving beams) to transmit (or receive) signals can be referred to as beam scanning.

[0138] Terminal 400 can measure reference signals (RS) corresponding to different transmit beams transmitted from the base station while maintaining a receive beam. In this case, the reference signals can correspond to Channel State Information Reference Signals (CSI-RS) or SSBs. Based on the reference signals, terminal 400 can measure the quality of each of the different transmit beams (e.g., the strength of the reference signal (e.g., RSRP) received by the transmit beam, or the channel quality of the transmit beam). Thereafter, terminal 400 can send a Channel State Information (CSI) report to base station 410 including the measurement results for the different transmit beams. Here, the measurement results for the different transmit beams can include information about the optimal beam 440 or information about the top N beams in terms of performance. Simultaneously, the information about the optimal beam can include an index of the optimal transmit beam, an index of the optimal receive beam, or at least one of the indices of each optimal transmit / receive beam, and can include channel quality information (CQI) about the optimal beam. Furthermore, information regarding the top N beams in terms of performance can be based on results obtained by measuring the signal strength or channel quality of different transmitted beams. The descending order refers to information about the N beams with the highest signal strength or channel quality. In this case, N can be predetermined, configured via upper-layer messages such as RRC messages, and indicated by control information sent from the base station.

[0139] On the other hand, when CSI-RS is used as a reference signal corresponding to different transmitted beams sent from the base station, the base station can determine the beam corresponding to CSI-RS according to various embodiments of the present disclosure described later, and can use CSI-RS for beam adjustment.

[0140] Figure 4B This illustrates the process of downlink receive beam adjustment performed by a terminal and base station according to this disclosure.

[0141] refer to Figure 4B When beam adjustment is performed by the downlink receiving side, the base station 410 can maintain the transmit beam, and the terminal 400 can adjust (or scan) the receive beam. For this purpose, the base station 410 can configure a set of downlink RS 460s in the terminal 400, and the terminal 400 can measure RS460 by sequentially applying the receive beam to the configured RS 460s. The terminal 400 can identify the optimal beam 470 based on the measurement results of RS 460. Meanwhile, in this disclosure, the downlink is described as an example, but this is merely for illustrative purposes, and the downlink beam adjustment process described above can be similarly applied when uplink beam adjustment is required.

[0142] Simultaneously, when the beam is changed due to the aforementioned beam management, the base station needs to notify the terminal of the beam change as a result of the beam management. In this disclosure, this may be referred to as beam indication, and will be referenced... Figure 5 Provide a detailed description.

[0143] Figure 5 A beam indication method in a next-generation wireless communication system according to the present disclosure is shown.

[0144] refer to Figure 5 In a next-generation wireless communication system according to this disclosure, when the optimal beam changes due to beam management, the base station can perform beam indication to notify the terminal of information about the beam change (or beam switching).

[0145] The aforementioned beam indication can be understood as providing an indication to the terminal that the Physical Downlink Shared Channel (PDSCH) or Physical Downlink Control Channel (PDCCH) is transmitting using the same beam as the RS (e.g., CSI-RS or SSB) configured in the terminal. Alternatively, the beam indication can be understood as indicating that the PDSCH or PDCCH is being transmitted using the same spatial filter as the configured RS. Furthermore, in this disclosure, transmitting or receiving PDSCH can be understood as transmitting or receiving data via PDSCH, and transmitting or receiving PDCCH can be understood as transmitting or receiving DCI via PDCCH.

[0146] Meanwhile, the beam indication method according to this disclosure can be performed using downlink signaling that transmits configuration indicator state (TCI state) information.

[0147] The base station can use TCI status information to notify the terminal about beam information related to downlink transmission (PDSCH or PDCCH transmission). The UE can assume that the PDSCH or PDCCH and RS (e.g., CSI-RS or SSB) included in the TCI status information are transmitted through the same downlink transmission beam. That is, the base station can include information about CSI-RS and information about SSB in the TCI status information and notify the terminal that the PDSCH or PDCCH is transmitted through the same transmission beam as CSI-RS or SSB.

[0148] Specifically, the base station can configure N (e.g., a maximum of 128) TCI states for the terminal. These N TCI states can be included in information elements (IEs) (e.g., PDSCH-Config) within upper-layer messages such as RRC messages (e.g., RRC reconfiguration messages) sent by the base station to the terminal. Furthermore, the base station can configure M (e.g., up to 64) candidate TCI states from the N TCI states via upper-layer messages to indicate (or specify) the beam through which the PDCCH is transmitted. The configuration of each TCI state in the candidate TCI state list can be shown in Table 7 below. The relationship between the QCL configuration and the TCI states is as described above, depending on the configuration of each TCI state.

[0149] [Table 7]

[0150]

[0151] The base station can send configuration information of candidate TCI states to the terminal via upper-layer messages such as RRC messages, and the terminal can store the configuration information of candidate TCI states. In this case, the configuration information may include the information shown in [Table 8] and [Table 9] below, and the configuration information can be sent to the terminal via upper-layer messages in the form of logs.

[0152] [Table 8]

[0153]

[0154] [Table 9]

[0155]

[0156] Subsequently, when the beam changes, the base station can send a control message to the terminal via an L1 signal (e.g., downlink control information (DCI)) or an L2 signal (e.g., MAC CE) to indicate (or specify) the beam to be changed. For example, the base station can send information to the terminal about the beam switching period and about the changed beam, thereby changing the beam used for signal transmission / reception between the base station and the terminal. The terminal can receive the control message from the base station, identify the active TCI state information in the control message, and identify that the PDCCH is transmitted through the same beam as the RS (e.g., CSI-RS or SSB) associated with the active TCI state (e.g., the terminal can assume that the PDCCH is transmitted through the same spatial filter as the RS).

[0157] Furthermore, in the next-generation wireless communication system according to this disclosure, as mentioned above, since signal transmission / reception in the UHF band is taken into account, the beam state may vary relatively greatly depending on changes in the surrounding communication environment. Therefore, the optimal beam should be determined at the corresponding time point, and the transmitted and received signals should be performed in real time or continuously (in the background) to effectively operate the beamforming technology. In this regard, the beam management performed in real time or continuously by the terminal or base station in this disclosure can be referred to as beam tracking, and reference will be made below. Figures 6 to 7 Detailed description of beam tracking according to this disclosure.

[0158] Figure 6 The process of performing beam tracking according to an embodiment of the present disclosure is illustrated.

[0159] refer to Figure 6 The base station can send an SSB burst to the terminal, which includes at least one SSB corresponding to each of the different downlink transmit beams. The terminal can receive each SSB included in the SSB burst sent from the base station while maintaining its receive beam, and measure its channel quality (here, channel quality may include channel state, signal strength, etc.). Furthermore, the terminal can receive its own receive beam for each SSB burst by alternating between sequential and random reception. The terminal can receive the SSBs included in the SSB burst as described above and measure their channel quality. The terminal can store information about each downlink receive / transmit beam pair (e.g., this may include information about the downlink receive beam, information about the downlink transmit beam, measurement results of the signal strength of the SSB received through the corresponding downlink receive / transmit beam pair, and the channel quality of the corresponding downlink receive / transmit beam pair). Here, the terminal can store the above-mentioned information about the downlink receive / transmit beam pairs in a beam database (DB) in the form of a table as shown in Table 10 below.

[0160] [Table 10]

[0161]

[0162] Subsequently, the terminal can determine the optimal beam based on stored information about the downlink transmit / receive beam pair, and can send (or report) information about the determined optimal beam to the base station (e.g., this may include an index of the optimal transmit beam, an index of the optimal receive beam, or at least one of the indices of each optimal transmit / receive beam, and may include channel quality information (CQI) for the optimal beam). For example, when a CSI-RS report is triggered (aperiodic CSI-RS reporting), or when a CSI-RS report is performed every predetermined period (periodic CSI-RS reporting), the terminal can report a CSI-RS report to the base station including information about the optimal beam. Meanwhile, for ease of explanation, this disclosure... Figure 6 This is illustrated by assuming that an SSB burst is sent from the base station to the terminal every 20 ms, the terminal performs a CSI report every 40 ms, the terminal has 21 receive beams, and the base station has 56 transmit beams. However, this is merely an example for ease of explanation, and this disclosure is not limited thereto. For example, the number of receive beams at the terminal can be increased when transmitting / receiving signals in a higher frequency band.

[0163] At the same time, such as Figure 6As shown, in order for the terminal to measure the SSBs transmitted from the base station to perform beam tracking, as described above, the terminal should sequentially or randomly scan its own receive beam for each SSB burst transmitted by the base station. While maintaining the receive beam corresponding to each SSB burst, it should also receive SSBs corresponding to different transmit beams included in the SSB burst and measure their channel quality. For example, if the terminal can generate (form) multiple receive beams with n different orientations, and the base station can generate multiple transmit beams with k different orientations, since the terminal should receive SSB bursts including SSBs corresponding to the k transmit beams respectively, and simultaneously sequentially or randomly select multiple n receive beams, information about the actual optimal beam can only be obtained when measuring the channel quality for a total of n×k pairs of transmit and receive beams. That is, information about the actual optimal beam can only be obtained when a full scan of the terminal's receive beam is performed relative to the base station's transmit beams. However, in systems considering signal transmission and reception in the terahertz or ultra-high frequency bands, such as the next-generation wireless communication system according to this disclosure, the number of receive or transmit beams of the terminal or base station increases to address the problem of reduced base station coverage. Therefore, the time required to complete a full scan of the terminal's receive beam relative to the base station's transmit beam may be longer than the CSI reporting period, and the beam state may change within a short time. In this case, information about the receive or transmit beam, which is no longer the optimal beam at the time of the CSI report because receive or transmit beam measurements were performed long ago, may be sent to the base station via CSI reporting. Therefore, beam tracking may not adequately reflect changes in the communication environment, and thus beam tracking performance may degrade. To address this problem, in addition to referencing... Figure 6 In addition to the described beam tracking methods, this disclosure also proposes a beam tracking method using Channel State Information Reference Signals (CSI-RS). The reference signal will be... Figure 7 To describe its detailed description.

[0164] Figure 7 The process of performing beam tracking according to an embodiment of the present disclosure is illustrated.

[0165] refer to Figure 7 The base station can send an SSB burst to the terminal, which includes at least one SSB corresponding to each of the different downlink transmission beams. The terminal can receive each SSB included in the SSB burst sent from the base station while maintaining its receive beam, and measure its channel quality (here, channel quality may include channel state, signal strength, etc.). Furthermore, the terminal can receive its own receive beam for each SSB burst by alternating between sequential and random reception. The terminal can receive the SSBs included in the SSB burst as described above and measure its channel quality. Meanwhile, with reference... Figure 6 The described beam tracking methods differ; refer to [reference needed]. Figure 7 The described beam tracking method can perform beam tracking on CSI-RS transmitted by the base station.

[0166] Specifically, as described above, the base station can send TCI status information to the terminal via upper-layer messages such as RRC messages. The terminal can identify information about the CSI-RS corresponding to the SSB (e.g., information about CSI-RS resources) based on the TCI status information, and can identify the beam corresponding to the CSI-RS based on the information about the CSI-RS. Therefore, the terminal can receive the CSI-RS corresponding to at least one downlink transmit beam of the base station while maintaining its own receive beam, and measure its channel quality (here, channel quality refers to channel state, signal strength, etc.). In this case, the terminal's receive beam may refer to the best receive beam identified by referring to a pre-stored beam database or the beam corresponding to one of the top N beams in terms of performance. The terminal can store information about each downlink receive / transmit beam pair (e.g., this may include information about the downlink receive beam, information about the downlink transmit beam, measurement results of the signal strength of the CSI-RS or SSB received through the corresponding downlink receive / transmit beam pair, and the channel quality of the corresponding downlink receive / transmit beam pair). Here, the terminal can store the aforementioned information about the downlink receive / receive beam pairs in a beam database (DB) in the form of a table as shown in [Table 10] above. Subsequently, the terminal can determine the optimal beam based on the stored information about the downlink transmit / receive beam pairs, and can send (or report) information about the determined optimal beam to the base station (e.g., this may include an index of the optimal transmit beam, an index of the optimal receive beam, or at least one of the indices of each optimal transmit / receive beam, and may include channel quality information (CQI) for the optimal beam). For example, when a CSI-RS report is triggered (aperiodic CSI-RS reporting), or when a CSI-RS report is performed every predetermined period (periodic CSI-RS reporting), the terminal can report a CSI-RS report to the base station including information about the optimal beam. Meanwhile, for ease of explanation, this disclosure... Figure 7 This is illustrated by assuming that an SSB burst is sent from the base station to the terminal every 20 ms, the terminal performs a CSI report every 40 ms, the terminal has 21 receive beams, the base station has 56 transmit beams, the beam indices corresponding to CSI-RS are 26, 29, 30, and 33, and the CSI-RS is sent exactly before the CSI report timing. However, this is merely an example for ease of explanation, and this disclosure is not limited thereto.

[0167] According to this disclosure Figure 7 The proposed beam tracking method allows the terminal to transmit the downlink beam corresponding to the CSI-RS at the same time the base station transmits the CSI-RS, and additionally performs a scan of the received beam. Therefore, the time required for a full beam scan of the received beam can be shortened, allowing for faster updates of information about the transmit / receive beam pairs. Consequently, information about the actual optimal beam can be identified at the CSI reporting time point, and this optimal beam information can be reported to the base station, thus enabling beam tracking with improved performance.

[0168] Simultaneously, the base station that has received the terminal's CSI report can determine whether to change the beam used for signal transmission / reception between the terminal and the base station based on the information about the optimal beam included in the CSI report. If the base station determines to change the beam, it can send a control message indicating the changed beam to the terminal via an L1 signal (e.g., DCI) or an L2 signal (MAC CE), as described above. Figure 5 The method described herein is used to perform beam indication on the changed beam. Furthermore, in the beam tracking method proposed in this disclosure, the base station can determine the beam corresponding to the CSI-RS based on various methods, and will refer to... Figure 8 To describe its example.

[0169] Figure 8 An example is shown of determining the beam corresponding to CSI-RS in beam tracking according to an embodiment of the present disclosure.

[0170] exist Figure 8The example illustrates a scenario where a base station receives information from a terminal via a CSI report that the beam corresponding to beam index (or SSB index) 29 (a beam different from the conventional optimal beam) is the optimal beam. The base station can identify beams adjacent to the beam at beam index 29 in the beambook (e.g., beams with beam indices 26, 30, and 33) as beams corresponding to the CSI-RS. Alternatively, in this disclosure, an adjacent beam can mean a beam spatially adjacent to the optimal beam, identified based on at least one of horizontal angle, vertical angle, or various spatial parameters. Furthermore, the number of beams corresponding to the CSI-RS can be determined based on terminal capabilities, etc., and can be randomly determined by the base station. According to this disclosure, a base station can determine whether to change the beam corresponding to the CSI-RS based on information about the optimal beam included in the CSI report. When the CSI report includes information about beams different from the conventional optimal beam, the base station can change (or determine) the beam corresponding to the CSI-RS by referring to TCI status information. In other words, the base station identifies information about adjacent beams (e.g., SSB index) based on the beam information included in the CSI report, and can identify information about the CSI-RS corresponding to the adjacent beams (e.g., CSI-RS-Resource ID) based on the TCI status information. The base station can then send (or provide) the CSI-RS identified based on the information about the CSI-RS to the terminal, enabling beam tracking according to this disclosure to be performed.

[0171] On the other hand, when considering signal transmission and reception in the UHF band as in the next-generation wireless communication system according to this disclosure, changes such as signal attenuation and channel rate of change can occur rapidly depending on the direction (or orientation) of the terminal and its speed of movement. Therefore, the beams selected as the optimal beams are the same, even if they are spatially different or not adjacent, or even when the beams are different, the selection trend of the optimal beam (e.g., the number of times it is selected as the optimal beam for each beam index, or its probability distribution, etc.) can be similar. That is, even when the beams are spaced apart according to location, the beam pattern (which may be referred to as a beam selection pattern, indicating a pattern or probability distribution of the probability of the optimal beam being selected for each beam index, or a term with the same meaning, and which will be described as a beam pattern later in this disclosure) can be similar. Furthermore, in the next-generation wireless communication system according to this disclosure, even considering varying factors in various communication environments, the beam selected as the optimal beam for each terminal location due to the signal characteristics of the UHF band can correspond to a portion of multiple beams. To address this, this disclosure proposes a method in which a base station generates (or identifies) a beam pattern for a specific location based on the location information of a terminal and information about the optimal beam at the corresponding location; performs clustering within the same cluster according to predetermined criteria to include beam patterns determined to be the same or similar in the generated beam patterns (or, it may be referred to as terms with the same or similar meaning, such as sets or groups, which will be described as clusters in this disclosure later); determines the beam corresponding to CSI-RS based on the clustering results; and then performs beam tracking based on the beam determination. This will refer to Figure 9 Describe it.

[0172] Figure 9 An example is shown of determining the beam corresponding to CSI-RS in beam tracking according to an embodiment of the present disclosure.

[0173] refer to Figure 9The base station determines a beam corresponding to the CSI-RS for each location and can transmit the CSI-RS to the terminal via the beam based on the terminal's location. For example, if the number of times the beams corresponding to beam indices 10, 29, 46, and 54 are selected as the best beams in the cluster corresponding to the terminal's current location is high, the base station can determine the beams corresponding to beam indices 10, 29, 46, and 54 as the beams corresponding to the CSI-RS. The base station can identify information about the beams determined to correspond to the CSI-RS (e.g., SSB index) and can identify information about the CSI-RS corresponding to the determined beams based on TCI status information (e.g., CSI-RS-Resource ID). The base station can then send the CSI-RS identified based on the information about the CSI-RS to the terminal. The above examples are provided to facilitate the description of embodiments of this disclosure, and this disclosure is not limited thereto.

[0174] Therefore, according to the beam tracking method provided in this disclosure, the beam most likely to be selected as the optimal beam at the terminal location can be sent to the terminal corresponding to the CSI-RS, thereby further improving beam tracking performance. Furthermore, according to the beam tracking method proposed in this disclosure, it is not necessary to change the beam corresponding to the CSI-RS by reporting location information such as GPS information to the base station every time the terminal's location changes. Only in the case of a cluster change (e.g., when the terminal has moved and the cluster ID corresponding to the terminal's location changes), information about the changed cluster (e.g., the changed cluster ID) is sent to the base station, and the base station changes the beam corresponding to the CSI-RS based on the information about the changed cluster, thereby effectively reducing signaling load. Moreover, since the base station can operate the CSI-RS for each cluster, rather than assigning and operating the CSI-RS for each terminal, a more efficient communication system can be established. In the following, reference will be made to… Figures 10A to 19 The beam tracking method proposed in this disclosure is described in detail. On the other hand, the beam tracking method proposed in this disclosure can be performed based on CSI-RS or SSB (SSB burst) transmitted from the base station, as described above. Figure 6 and Figure 7 As described in [the document]. However, in the following text, in order not to obscure the key points of this disclosure, the method of performing beam tracking based on CSI-RS will be described primarily.

[0175] Figure 10A and Figure 10B An example of a method for performing beam tracking by clustering beam patterns at a specific location according to embodiments of the present disclosure is shown.

[0176] refer to Figure 10AA base station can send signals to terminals located at different locations within its coverage area of ​​1000 and receive signals from terminals located at different locations within its coverage area of ​​1000. The base station can receive information from each terminal regarding the optimal beam at the corresponding location. Based on the information received from the terminal regarding the optimal beam, the base station can identify the number of times the corresponding beam is selected for each beam index at the terminal's location and store the selection count in a database (DB) or in a table. For ease of illustration, as... Figure 10A As shown, it can be assumed that the coverage of a base station is divided into a grid structure 1000 with 5m intervals. Therefore, each of the subdivided grids 1001, 1002, and 1003 can be represented by two-dimensional coordinates, such as (X, Y). The coverage segmentation method described above is provided for the convenience of describing embodiments of this disclosure, and this disclosure is not limited thereto. That is, it can be assumed that the subdivision interval (e.g., 2m, 3m, etc.) or structure (e.g., grid structure, etc.) is determined based on the communication environment (e.g., the number of terminals within the coverage area, the number of adjacent base stations, signal strength, etc.), and the coverage area 1000 is subdivided accordingly. Furthermore, the position according to the aforementioned grid structure can refer to the position obtained by transforming the terminal's position information identified by Global Positioning System (GPS) information, etc., according to predetermined mapping information (or mapping table). For example, when the terminal's position is identified by GPS information, the position according to the grid structure can correspond to a transformed value (coordinates) identified by applying GPS information to predetermined map information. Simultaneously, clustering, which will be described later, can be performed based on the position according to the grid structure. For example, based on the results of clustering, positions corresponding to (5,0) and (0,5) according to the grid structure can be included in the same cluster. In this case, each of the positions (5,0) and (0,5) can correspond to a cluster.

[0177] The base station can receive information about the optimal beam at each of terminals 1001, 1002, and 1003 located in each of the subdivided grids 1001, 1002, and 1003. Based on the information about the optimal beam received from terminals 1001, 1002, and 1003, the base station can identify the number of times the corresponding beam at the location of the corresponding terminal 1001, 1003, and 1002 is selected as the optimal beam for each beam index, and can store the selection count for each beam index in the form of tables 1005, 1006, and 1007 as shown in [Table 11] below. For example, in the case of location (40,0), the selection count for each beam index can be stored (or identified) in the base station in the form of the following table. Meanwhile, in this disclosure... Figure 10A and Figure 10BFor ease of explanation, it is assumed that clustering according to this disclosure is performed based on the number of beam selections with beam indices of 0, 1, 2, and 3, but this disclosure is not limited thereto. That is, clustering according to this disclosure can be performed by considering the number of all beam selections available at the terminal location (i.e., the number of selections for all beam indices).

[0178] [Table 11]

[0179]

[0180] refer to Figure 10B The base station can generate (or identify) beam patterns 1010, 1011, and 1012 based on a stored (identified) table and according to the corresponding locations (i.e., the probability distribution of beam selection). Meanwhile, in this disclosure, a beam pattern can refer to a probability vector indicating the probability of selecting a beam at a corresponding location based on each beam index. For example, [Table 11] can display the probability vectors in order of beam index. Meanwhile, the base station can generate beam patterns 1010, 1011 and 1012 based on various methods (e.g., various statistical techniques), and this disclosure is not limited thereto.

[0181] The base station can perform clustering such that beam patterns identified as identical or similar based on predetermined criteria in the generated beam patterns 1010, 1011, and 1012 are included in the same cluster. In this disclosure, clustering can be referred to using terms with the same or similar meanings, such as clustering, aggregation, assembly, and grouping. Furthermore, in this disclosure, when determining whether beam patterns are identical or similar, the base station can use a similarity calculation method based on Euclidean distance, a similarity calculation method based on cosine similarity, or various methods for determining the similarity between entities. For example, when the Euclidean distance value between the generated beam patterns 1011 and 1012 is equal to or less than a predetermined threshold, or the cosine similarity value is equal to or greater than a predetermined threshold, the base station can perform clustering to allow the beam patterns to be included in the same cluster 1022. Alternatively, when the Euclidean distance between the generated beam patterns 1010 and 1011 is equal to or greater than a predetermined threshold, or the cosine similarity value is equal to or less than a predetermined threshold, the base station can perform clustering to allow the beam patterns to be included in different clusters 1021 and 1022, respectively. Alternatively, as a result of applying the above similarity determination method to a randomly generated probability distribution (or probability vector), when beam patterns have a similarity value equal to or greater than a predetermined threshold, clustering can be performed to include them in the same cluster 1022. Furthermore, as a result of applying the above similarity determination method to a randomly generated probability distribution (or probability vector), when beam patterns have a similarity value equal to or greater than a predetermined threshold, clustering can be performed to include them in different clusters 1021 and 1022, respectively. Simultaneously, the base station can perform clustering according to this disclosure based on various machine learning algorithms. For example, the base station can perform clustering according to this disclosure based on the K-means clustering algorithm in machine learning algorithms (where K can represent the number of clusters), and in this case, the processing shown in [Table 12] can be performed.

[0182] [Table 12]

[0183]

[0184] Furthermore, in this disclosure, when a base station performs location-specific beam pattern clustering, the number of clusters (K) can be determined according to various criteria. For example, the base station can predetermine a random value as the number of clusters and perform clustering based on the determined number of clusters. Alternatively, the base station can determine the number of clusters (e.g., a maximum of 64) using a random value and perform clustering by increasing or decreasing the determined number of clusters by a predetermined number at predetermined intervals. As a result of performing clustering based on the increased or decreased number of clusters, when a predetermined number or more random accesses occur to terminals within the base station's coverage area (e.g., random access due to beam failure), the base station can change (increase or decrease) the number of clusters to perform clustering. Alternatively, the number of clusters can be determined based on at least one of the number of terminals within the base station's coverage area, the channel state with the terminals, the channel load level, and network congestion. Furthermore, when the base station performs location-specific beam pattern clustering based on the machine learning algorithm described above (e.g., K-means clustering), a performance value for each number of clusters can be calculated, and "K" can be determined as the number of clusters with the highest performance value, a predetermined performance value, or a higher performance value. For example, when the base station uses the K-means clustering algorithm, the number of clusters with contour values ​​close to 1 can be determined. Subsequently, as a result of clustering, the base station can identify beam patterns 1021 and 1022 for each cluster. The beam pattern of each cluster can represent the beam pattern corresponding to the corresponding cluster, can correspond to any of the location-specific beam patterns belonging to the cluster, or can refer to the beam pattern generated (identified) by applying various statistical techniques (such as averaging and normalizing the location-specific beam patterns belonging to the cluster) and is representative relative to the location-specific beam patterns belonging to the cluster.

[0185] After performing clustering, the base station can store information indicating which cluster each location belongs to in the form of Table 1030, as shown in [Table 13], based on the clustering results. Meanwhile, in this disclosure, Table 1030 indicating the clustering results can be referred to as Table 1030 including mapping information between locations and clusters (or information about the correspondence between them), mapping table 1030, clustering information for each location, or clustering information, and can be referred to as a term with the same or similar meaning. Hereinafter, this will be referred to as clustering information.

[0186] [Table 13]

[0187] Location Cluster ID (10,20) 1 (20,30) 2 (30,20) 3 (20,10) 4 … …

[0188] The base station can provide (or send) clustering information 1030 to the terminal via upper-layer messages such as RRC messages, and the terminal can perform beam tracking as proposed in this disclosure based on the clustering information 1030. The detailed operation of the terminal and base station performing beam tracking based on the aforementioned clustering information according to this disclosure will be described below.

[0189] First, the operations of the terminals and base stations used to generate (or acquire, determine) the above clustering information will be described.

[0190] Figure 11 The illustration shows a processing sequence in which a terminal sends location information and information about the beam pattern at the corresponding location to a base station, according to an embodiment of the present disclosure.

[0191] In operation 1101, the terminal can identify (or generate or obtain) its location information based on various methods. For example, the terminal can identify its location information based on Global Positioning System (GPS) information received from satellites. In this case, the location information can refer to information identified by a predetermined table including the GPS information itself or the correspondence between GPS information and the terminal's location. Alternatively, the location information can be identified based on channel frequency response or power delay profile. Channel frequency response refers to the amplitude values ​​of subcarriers in a frequency band, and the terminal's location information can be identified based on the subcarrier amplitude values ​​received in each frequency band within a predetermined time period. Power delay profile refers to the time when a signal transmitted to the terminal arrives at the terminal and the strength of the signal. Although radio waves are transmitted simultaneously, they arrive at the receiver at different times via various paths, so the terminal's location information can be identified based on the time it takes for the signal to reach the terminal and the strength of the signal. Meanwhile, in this disclosure, the terminal's location information can refer to the conversion of values ​​identified based on channel frequency response or power delay profile into location information according to predetermined mapping information (or a mapping table). On the other hand, if the terminal can identify the location information itself or already knows the location information, operation 1101 can be omitted, and operation 1102, which will be described later, can be executed immediately. Alternatively, operation 1101 can be executed simultaneously with operation 1102, which will be described later.

[0192] In operation 1102, the terminal may include the location information identified in operation 1101 in the measurement report and send it to the base station.

[0193] In operation 1103, as referenced Figures 6 to 7The terminal can perform SSB-based beam scanning. While maintaining its receiving beam, the terminal can receive each SSB included in an SSB burst transmitted from the base station and measure its channel quality (here, channel quality may include channel state, signal strength, etc.). Furthermore, the terminal can use its own receiving beam alternately, sequentially, or randomly to receive SSBs included in each SSB burst using the method described above, and measure their channel quality. The terminal can store information about each downlink receive / transmit beam pair (e.g., information about the downlink receive beam, information about the downlink transmit beam, and the corresponding downlink receive / transmit beam pair). As a result of measuring the received signal strength of the SSB, the channel quality of the corresponding downlink receive / transmit beam pair can be stored. In this case, the terminal can store the above-mentioned information about the downlink receive / transmit beam pairs in a beam database (DB) in the form of a table as shown in [Table 10].

[0194] In Operation 1104, when a CSI report is triggered, the terminal can identify information about the best beam or information about the top N beams in terms of performance at a given time point, based on a beam database or table that includes information about downlink receive / receive beam pairs. This information is then included in the CSI report and sent to the base station. The information about the best beam may include an index of the best transmit beam, an index of the best receive beam, or an index of each best transmit / receive beam, and may include channel quality information (CQI) for the best beam. Furthermore, the information about the N beams with good performance can be based on results obtained by measuring the signal strength or channel quality of different transmit beams, arranged in descending order to refer to information about the beams corresponding to the N beams with the highest ranked signal strength or channel quality. In this case, N can be predetermined, configured via upper-layer messages such as RRC messages, and indicated by control information sent from the base station.

[0195] at the same time, Figure 11 Operations 1101 to 1104 shown may be partially omitted or may be executed simultaneously. Furthermore, operations 1101 to 1104 may be executed periodically at predetermined intervals, or they may be performed non-periodically when the base station determines that clustering information needs to be updated and triggers the execution of operations 1101 to 1104.

[0196] At the same time, Figure 11In this context, when a terminal sends GPS information as location information, the number of bits in the GPS information is large, and overhead may occur when the terminal reports the location information to the base station. To address this, according to embodiments of this disclosure, the terminal can measure the signal strength (e.g., Reference Signal Received Power (RSRP)) of a reference signal transmitted from a neighboring base station (e.g., an NR gNB or an LTE eNB), and can send a list of the reference signal strength measurement results to the base station. Here, the list of reference signal strength measurement results can be as shown in [Table 14] below.

[0197] [Table 14]

[0198] Base station ID RSRP (dBm) 1 -68 2 -92 3 -58 4 -63 … …

[0199] The reason a base station can determine the location of a terminal based on a list of reference signal strength measurements is that signal strength, such as RSRP values, is a distance-based value, and the terminal's location can be identified based on multiple RSRP values. Specifically, the base station can identify the terminal's location by applying various positioning techniques, such as triangulation, to multiple measured RSRP values. Alternatively, by comparing multiple measured RSRP values ​​with RSRPs pre-stored in a database (DB), the base station can identify locations with similar RSRP values ​​as the terminal's location. Figure 12 This will describe in detail the terminal's operation when the base station identifies the terminal's location information based on a list of strength measurements of reference signals sent by the terminal.

[0200] Figure 12 The present disclosure illustrates an embodiment in which a terminal transmits a list of signal strength measurement results of a reference signal to a base station and a processing sequence of information regarding the beam pattern at the corresponding location.

[0201] In addition to transmitting GPS information, which serves as the terminal's location information, to the base station via CSI reports, ... Figure 11 different, Figure 12 An embodiment is shown in which a terminal measures the signal strength (e.g., RSRP) of a reference signal transmitted from a neighboring base station, and the base station identifies the terminal's location information based on a list of the signal strength measurements of the reference signals transmitted to the base station.

[0202] refer to Figure 12 In operation 1201, the terminal can measure the signal strength of a reference signal received from an NR gNB or LTE eNB (e.g., RSRP, RSRQ, etc.) and can identify (or obtain) a list of reference signal strength measurement results, as shown in Table 14 above.

[0203] In Operation 1202, the terminal can report a list of signal strength measurement results of the reference signal to the base station through a measurement report.

[0204] In operation 1203, as referenced Figures 6 to 7 The terminal can perform SSB-based beam scanning. While maintaining its receiving beam, the terminal can receive each SSB included in an SSB burst received from the base station and measure its channel quality (here, channel quality may include channel state, signal strength, etc.). Furthermore, the terminal can use its own receiving beam alternately, sequentially, or randomly to receive SSBs included in each SSB burst and measure their channel quality for each SSB burst using the method described above. The terminal can store information about each downlink receive / transmit beam pair (e.g., information about the downlink receive beam, information about the downlink transmit beam, measurement results of the signal strength of the SSB received through the corresponding downlink receive / transmit beam pair, and the channel quality of the corresponding downlink transmit / receive beam pair). Here, the terminal can store the aforementioned information about the downlink receive / transmit beam pairs in a beam database (DB) in the form of a table as shown in [Table 10] above.

[0205] In Operation 1204, when a CSI report is triggered, the terminal can identify information about the best beam or information about the top N beams in terms of performance at the corresponding time point based on a beam database or table that includes information about downlink receive / transmit beam pairs, and include the information in the CSI report and send it to the base station.

[0206] at the same time, Figure 12 Operations 1201 to 1204 shown may be partially omitted or may be executed simultaneously. Furthermore, operations 1201 to 1204 may be executed periodically at predetermined intervals, or non-periodically when the base station determines that clustering information needs to be updated and triggers the execution of operations 1201 to 1204.

[0207] Furthermore, the terminal disclosed herein can selectively send data to the base station. Figure 11 Location information or Figure 12The base station can use a table (or function, etc.) containing predetermined mapping information to convert the terminal's location information, identified based on the list of signal strength measurement results of the received GPS information or reference signal, into relative location information, and determine the converted location information as the terminal's location information. In other words, the base station can unify the terminal's location information, represented as a list of GPS information or signal strength measurement results of the reference signal, into a single unit using a table (or function) containing predetermined mapping information, and can store and manage it in a database. Furthermore, with... Figure 12 Unlike the list of reference signal strength measurement results sent by the terminal to the base station, the terminal can measure the signal strength of reference signals received from neighboring base stations and identify its own location information based on triangulation, or it can identify its own location information by referring to the signal strength correlation database stored in the terminal. The identified location information is included in the measurement report, which is then sent. In this case, the terminal can perform actions based on... Figure 11 The operation.

[0208] The base station can generate a location-specific beam pattern based on information received from the terminal regarding the optimal beam and the terminal's location information, and can cluster the generated beam patterns. (Refer to...) Figure 13 To describe the detailed operation of the base station.

[0209] Figure 13 The present disclosure illustrates an embodiment in which a base station identifies a location-specific beam pattern based on the location information of a terminal and information about the optimal beam, and performs a processing sequence for clustering the beam patterns.

[0210] refer to Figure 13 In Operation 1301, the base station can receive measurement reports from the terminal based on... Figure 11 The location information of the terminal or according to Figure 12 A list of signal strength measurements for the reference signal. The base station can store location information in a database or in tabular form.

[0211] In operation 1302, the base station may send an SSB burst to the terminal, the SSB burst comprising at least one SSB corresponding to each of the different transmit beams.

[0212] In operation 1303, the base station can receive information from the terminal regarding the best beam or the top N beams in terms of performance. This information is identified based on the channel quality results of measuring the SSB bursts transmitted in operation 1302 by triggering CSI reports or every CSI report cycle, and the received information can be stored in a database in tabular form. Simultaneously, the aforementioned information regarding the best beam or the top N beams in terms of performance can be included in the CSI report and reported from the terminal to the base station.

[0213] In operation 1304, the base station can generate (or identify, obtain, determine) a beam pattern at the corresponding location based on the location information of the terminal identified in operation 1301 and the information about the best beam or the top N beams in terms of performance received in operation 1303.

[0214] In operation 1305, the base station can perform clustering based on the beam patterns generated in operation 1304. The base station can cluster the beam patterns already generated in operation 1304 based on various methods. For example, the base station can allow beam patterns determined to be similar to the patterns generated in operation 1304 by a predetermined threshold or greater to be included in the same cluster. Furthermore, in this disclosure, the methods used by the base station to cluster beam patterns are not limited and can be performed based on various machine learning algorithms or artificial intelligence systems. Since references have been made... Figure 10A and Figure 10B The detailed clustering process is described, so it will be omitted here. The base station can identify the beam pattern of each cluster based on the clustering results of operation 1305. The beam pattern of each cluster can represent the beam pattern corresponding to the corresponding cluster, can correspond to any of the location-specific beam patterns belonging to the cluster, or can refer to a beam pattern generated (identified) by applying various statistical techniques (such as averaging and normalization of location-specific beam patterns belonging to the cluster) and is representative relative to the location-specific beam patterns belonging to the cluster. Furthermore, the base station can obtain clustering information indicating which cluster each location belongs to (or, the cluster corresponding to each location) based on the clustering results. The clustering information can include information about the location and the cluster to which the corresponding location belongs (e.g., cluster ID), as well as information about the correspondence between the location and the cluster.

[0215] Furthermore, in operation 1306, the base station can send the clustering information obtained in operation 1305 to the terminal via upper-layer messages such as RRC messages.

[0216] at the same time, Figure 13Operations 1301 to 1306 shown may be partially omitted or may be executed simultaneously. Furthermore, operations 1301 to 1306 may be executed periodically at predetermined intervals, or may be executed non-periodically when the base station determines that clustering information needs to be updated and triggers the execution of operations 1301 to 1306.

[0217] Figure 14 The overall flow of the process by which a base station acquires clustering information according to an embodiment of the present disclosure is shown.

[0218] refer to Figure 14 In operation 1410, terminal 1400 can identify location information. This location information may include GPS information received from satellites, as referenced above. Figure 11 Alternatively, the location information may include information about the location of the terminal 1400 identified based on the result of measuring the signal strength of reference signals received from neighboring base stations.

[0219] In operation 1415, terminal 1400 can include the identified location information in the measurement report and report it to base station 1405.

[0220] In operation 1420, base station 1405 may store the location information of terminal 1400 received in operation 1415 in a database or in a table format. On the other hand, if base station 1405 receives a list of reference signal strength measurement results from terminal 1400 in operation 1415, base station 1405 may store the list of reference signal strength measurement results in a database or in a table format.

[0221] In operation 1425, base station 1405 may send an SSB burst to terminal 1400, the SSB burst including at least one SSB corresponding to each of the different transmission beams.

[0222] In operation 1430, terminal 1400 can update the beam database by performing an SSB-based beam scan. Terminal 1400 can receive each SSB included in the SSB burst transmitted from base station 1405 in operation 1425 while maintaining the receive beam, and measure its channel quality (here, channel quality may include channel state, signal strength, etc.). Furthermore, terminal 1400 can use its own receive beam alternately, sequentially, or randomly relative to each SSB burst using the method described above, and measure its channel quality. Terminal 1400 can store information about each downlink receive / transmit beam pair (e.g., information about the downlink receive beam, information about the downlink transmit beam, measurement results of the signal strength of the SSB received through the corresponding downlink receive / transmit beam pair, and the channel quality of the corresponding downlink transmit / receive beam pair). Here, terminal 1400 can store the above-described information about the downlink receive / transmit beam pair in the beam database (DB) in the form of a table as shown in [Table 10] above.

[0223] In operation 1435, when a CSI report is triggered, terminal 1400 can identify information about the best beam or the top N beams in terms of performance at the corresponding time point based on a beam DB or table that includes information about downlink receive / transmit beam pairs, include the information in the CSI report, and send it to base station 1405.

[0224] In operation 1440, base station 1405 can store information received via CSI reports regarding the optimal beam or the top N beams in terms of performance in a database or in tabular form. In this case, base station 1405 can store the terminal location information stored in operation 1430, corresponding to the information regarding the optimal beam or the top N beams. In this case, base station 1405 can identify (count) the number of times the optimal beam is selected for each beam index at the corresponding location based on the information regarding the optimal beam or the top N beams, and store this in tabular form. Base station 1405 can generate (or identify, acquire, determine) the beam pattern at the corresponding location based on the stored terminal location information and the information regarding the optimal beam or the top N beams at that location.

[0225] In operation 1445, base station 1405 can perform clustering based on the beam patterns generated in operation 1440. For example, base station 1405 can allow beam patterns determined to be similar to the patterns generated in operation 1440 by a predetermined threshold or greater to be included in the same cluster. Furthermore, in this disclosure, the method by which base station 1405 clusters beam patterns is not limited and can be performed based on various machine learning algorithms or artificial intelligence systems. Since references have been made... Figure 10A and Figure 10B The detailed clustering process is described, and therefore will be omitted here. Meanwhile, base station 1405 can identify the beam pattern of each cluster as a result of the clustering. The beam pattern of each cluster can represent the beam pattern corresponding to the corresponding cluster, can correspond to any of the location-specific beam patterns belonging to the cluster, or can mean that the beam pattern is generated (identified) by applying various statistical techniques (such as averaging and normalization of location-specific beam patterns belonging to the cluster) and is representative relative to the location-specific beam patterns belonging to the cluster. On the other hand, in this disclosure, when a large number of beams are selected in the beam patterns of a specific cluster with a probability equal to or greater than a predetermined threshold in each cluster's beam pattern, base station 1405 can increase the number of beams corresponding to the CSI-RS used for beam tracking in the corresponding cluster. Base station 1405 can send information about the increased number of beams to the terminal. In this scenario, since the number of transmit beams that can be measured by terminal 1400 during CSI-RS timing increases, and these beams correspond to beams that are highly likely to be selected as the optimal beam at the location of terminal 1400, an effect similar to that obtained by performing a full beam scan can be achieved. That is, as the number of beams corresponding to CSI-RS increases, the likelihood of obtaining information about the actual optimal beam during CSI reporting increases. On the other hand, when selecting only a specific beam with a probability equal to or greater than a predetermined threshold, base station 1405 can reduce the number of beams corresponding to CSI-RS. In this case, information about the reduced number of beams can be sent to terminal 1400. Furthermore, base station 1405 can identify (or acquire) clustering information indicating which cluster each location belongs to based on the clustering results. The clustering information may include information about the location and the cluster to which the location belongs (e.g., cluster ID), as well as information about the correspondence between the location and the cluster.

[0226] In operation 1450, base station 1405 can send the clustering information identified in operation 1445 to terminal 1400 via upper-layer messages such as RRC.

[0227] at the same time, Figure 14Operations 1410 to 1450 shown may be partially omitted or may be performed simultaneously. Furthermore, the first terminal, second terminal, or other terminal according to this disclosure may perform operations 1410 to 1450 simultaneously. Alternatively, operations 1410 to 1450 may be performed periodically at predetermined intervals, or non-periodically when the base station determines that clustering information needs to be updated and triggers the execution of operations 1410 to 1450.

[0228] The base station can be referenced above. Figures 11 to 14 The clustering information obtained by the described method is provided to the terminal, and a beam corresponding to the CSI-RS is determined based on each cluster. That is, since the beam corresponding to the CSI-RS can be determined based on the location of each terminal, beam tracking performance can be improved more effectively. Furthermore, the cluster change is only notified to the base station when a cluster change occurs due to terminal movement, so as to change the beam corresponding to the CSI-RS, thus significantly reducing signaling overhead. The method for performing beam tracking based on clustering information by a terminal and a base station according to this disclosure will be described in detail below.

[0229] Figure 15 An embodiment of the present disclosure is shown, in which a terminal performs a beam tracking processing sequence based on location information and clustering information received from a base station.

[0230] refer to Figure 15 In operation 1501, the terminal can perform initial access to the base station, and when the initial access is completed, the terminal can receive clustering information from the base station through upper-layer messages such as RRC messages.

[0231] In operation 1502, the terminal can identify its own location information based on GPS information received from satellites. Alternatively, the terminal can identify its location information by measuring the signal strength of a reference signal transmitted from a neighboring base station. As a method for identifying location information based on the signal strength of the reference signal, various positioning methods such as triangulation or methods for identifying location by referencing a previously stored signal strength correlation database can be used.

[0232] In operation 1503, the terminal can identify whether the cluster to which the terminal's location belongs has changed based on the clustering information received in operation 1501 and the location information identified in operation 1502. For example, the terminal can identify whether the cluster ID has changed based on the information about the correspondence between location and cluster ID included in the clustering information, and can perform the identification based on whether the cluster ID stored in the terminal is the same as or different from the identified cluster ID.

[0233] In operation 1504, when a change in the cluster corresponding to the terminal's location is detected, the terminal can include information about the changed cluster (e.g., the changed cluster ID) in the CSI report when the CSI report is triggered, and send it to the base station. Alternatively, GPS information can be sent to the base station. In this case, the base station can identify the change in the cluster corresponding to the terminal's location based on the received GPS information. Meanwhile, if it is determined that the cluster to which the terminal's location belongs has not changed, operation 1504 can be omitted.

[0234] Simultaneously, the information about the changed clustering reported by the terminal to the base station can be used to change the beam corresponding to CSI-RS. That is, in operation 1505, as described above... Figures 6 to 7 As described above, the terminal can receive CSI-RS corresponding to the changed beam based on information about the changed clustering, measure its channel quality, and then store it in the beam DB in the form of a table as shown in [Table 10]. Since the details have already been described above, a further description of the details will be omitted here.

[0235] at the same time, Figure 15 Operations 1501 to 1505 shown can be partially omitted or performed simultaneously. Furthermore, operations 1501 to 1505 can be performed periodically by the terminal at predetermined time intervals, and in this case, the period can be shorter than the period during which the base station updates the clustering information.

[0236] When the base station receives information about the changed clustering from the terminal, it can perform processing to change the beam corresponding to CSI-RS. This will be discussed in the following text. Figure 16 It is described in detail.

[0237] Figure 16 The diagram illustrates a sequence of processing steps for a base station to change the beam corresponding to CSI-RS according to an embodiment of the present disclosure.

[0238] refer to Figure 16 In Operation 1601, after the initial access process of the terminal is completed, the base station can send clustering information through upper-layer messages such as RRC messages.

[0239] Subsequently, in operation 1602, the base station can receive a CSI report from the terminal and can identify whether information about the changed cluster (e.g., the ID of the changed cluster) is included in the CSI report. Alternatively, the base station can identify whether the terminal's GPS information is included in the CSI report. If the information about the changed cluster (or GPS information) is included in the CSI report, the base station can perform operation 1603, which will be described later. Alternatively, if the information about the changed cluster is not included in the CSI report, it may mean that the cluster to which the terminal's location belongs has not changed, and therefore the base station can wait to receive the next CSI report (i.e., the base station can perform operation 1602).

[0240] When information about a changed cluster is identified in the received CSI report during operation 1602, the base station can change the beam corresponding to the CSI-RS based on the information about the changed cluster in operation 1603. Alternatively, when GPS information is included in the CSI report, the base station can identify information about a changed cluster based on the terminal's location using the GPS information. Specifically, the base station can identify the beam pattern in the changed cluster by referring to the information about the changed cluster in the stored clustering information. Then, based on the identified beam pattern, the base station can identify at least one beam that is highly likely to be selected as the optimal beam (e.g., the top N beams that are highly likely to be selected as the optimal beam, or the beam that is selected as the optimal beam with a probability equal to or greater than a predetermined threshold), and determine the identified at least one beam as the beam corresponding to the CSI-RS. In this disclosure, determining the beam corresponding to CSI-RS based on beam pattern can be understood as identifying at least one beam as the beam corresponding to CSI-RS by sampling the beam in a beam pattern indicating a probability distribution according to predetermined criteria. For example, when there are N beam indices that are selected as the optimal beam with a predetermined probability or greater, and there are K beam indices that can correspond to CSI-RS, the K beams can be sampled randomly from the N beams or by various methods, and the K beams can be determined as the beams corresponding to CSI-RS.

[0241] In operation 1604, the base station may send the CSI-RS corresponding to the beam determined in operation 1603 to the terminal. Here, the base station may identify information about the CSI-RS corresponding to the determined beam (e.g., CSI-RS-Resource ID) based on TCI state information and send the CSI-RS identified according to the CSI-RS information to the terminal. The terminal may receive the CSI-RS, measure the channel quality, and then store it in the DB in the form of a table as shown in [Table 10]. Furthermore, the terminal may report information about the optimal beam at the corresponding time point when the CSI is reported, thus enabling beam tracking according to this disclosure.

[0242] Figure 17 The overall process of a terminal and base station performing beam tracking based on clustering information according to embodiments of the present disclosure is illustrated.

[0243] In operation 1710, terminal 1700 performs initial access to base station 1705, and when the initial access is completed, terminal 1700 can receive clustering information from base station 1705 through upper-layer messages such as RRC messages.

[0244] refer to Figure 17 In operation 1715, terminal 1700 can identify its own location information based on GPS information received from satellites. Alternatively, terminal 1700 can use a method of measuring the signal strength of reference signals transmitted from neighboring base stations, and identify its location by referring to various positioning methods such as triangulation or pre-stored signal strength correlation databases.

[0245] In operation 1720, terminal 1700 can identify whether the cluster to which the location of terminal 1700 belongs has changed based on the clustering information received in operation 1710 and the location information identified in operation 1715. For example, terminal 1700 can identify whether the cluster ID has changed based on the information about the correspondence between location and cluster ID included in the clustering information, and can perform the identification based on whether the cluster ID stored in terminal 1700 is the same as or different from the identified cluster ID.

[0246] In operation 1725, when a cluster change corresponding to the location of terminal 1700 is identified, when a CSI report is triggered, terminal 1700 can include information about the changed cluster (e.g., the changed cluster ID) in the CSI report and send it to base station 1705. Conversely, if it is determined that the cluster to which the terminal's location belongs has not changed, operation 1725 can be omitted.

[0247] In operation 1730, base station 1705 can identify whether the CSI report received from terminal 1700 includes information about changed clusters (e.g., changed cluster IDs). If the information about changed clusters is included in the CSI report, base station 1705 can change the beam corresponding to the CSI-RS based on the information about the changed clusters. Specifically, base station 1705 can identify the beam pattern in the changed cluster by referring to the information about the changed clusters in the stored clustering information. Then, based on the identified beam pattern, base station 1705 can identify at least one beam that is highly likely to be selected as the best beam (e.g., the top N beams that are highly likely to be selected as the best beam, or the beam that is to be selected as the best beam with a probability equal to or greater than a predetermined threshold), and determine the identified at least one beam as the beam corresponding to the CSI-RS. In this disclosure, determining the beam corresponding to the CSI-RS based on the beam pattern can be understood as determining at least one beam as the beam corresponding to the CSI-RS, which is identified by sampling the beams according to predetermined criteria in a beam pattern indicating a probability distribution. For example, when there are N beam indices that are selected as the optimal beams with a predetermined probability or greater, and there are K beam indices that can correspond to the CSI-RS, the K beams can be sampled randomly from the N beams or by various methods, and the K beams can be determined as the beams corresponding to the CSI-RS. Alternatively, the absence of information about changed clusters in the CSI report may mean that the cluster to which the location of terminal 1700 belongs has not changed, so base station 1705 can wait to receive the next CSI report. Operation 1730 can be omitted here.

[0248] In operation 1735, base station 1705 may send the CSI-RS corresponding to the beam determined in operation 1730 to the terminal. Here, the base station may identify information about the CSI-RS corresponding to the determined beam (e.g., CSI-RS-Resource ID) based on TCI status information and send the CSI-RS identified according to the CSI-RS information to the terminal.

[0249] In operation 1740, terminal 1700 can receive CSI-RS transmitted from base station 1705, measure its channel quality, and then store it in DB in the form of a table as shown in [Table 10]. Subsequently, when a CSI report is triggered, terminal 1700 can identify information about the optimal beam at the corresponding time point by referring to DB or the table, include the identified information about the optimal beam in the CSI report, and report it to base station 1705, so that beam tracking as proposed in this disclosure can be performed.

[0250] Figure 18The structure of a terminal according to an embodiment of the present disclosure is shown.

[0251] refer to Figure 18 The terminal disclosed herein may include a terminal receiver 1800, a terminal transmitter 1810, and a terminal processor 1805. In embodiments of this disclosure, the terminal receiver 1800 and the terminal transmitter 1810 may be collectively referred to as a transceiver. The transceiver can transmit signals to / receive signals from a base station. The signals may include control information and data. For this purpose, the transceiver may include an RF transmitter and an RF receiver, the RF transmitter being configured to up-convert and amplify the frequency of the transmitted signal, and the RF receiver being configured to amplify and down-convert the received signal with low noise. Furthermore, the transceiver can receive signals via a wireless channel and output the received signals to the terminal processor 1805, and can also transmit signals output from the terminal processor 1805 via a wireless channel. The terminal processor 1805 can control a series of processes, enabling the terminal to operate according to the above embodiments of this disclosure.

[0252] Figure 19 The structure of a base station according to an embodiment of the present disclosure is shown.

[0253] refer to Figure 19 The base station disclosed herein may include a base station receiver 1900, a base station transmitter 1910, and a base station processor 1905. In embodiments of this disclosure, the base station receiver 1900 and the base station transmitter 1910 may be collectively referred to as a transceiver. The transceiver can transmit signals to / receive signals from a terminal. The signals may include control information and data. For this purpose, the transceiver may include an RF transmitter and an RF receiver, the RF transmitter being configured to up-convert and amplify the frequency of the transmitted signal, and the RF receiver being configured to amplify and down-convert the received signal with low noise. Furthermore, the transceiver can receive signals via a wireless channel and output the received signals to the base station processor 1905, and transmit signals output from the base station processor 1905 via a wireless channel. The base station processor 1905 can control a series of processes, enabling the base station to operate according to the above embodiments of this disclosure.

[0254] The embodiments of this disclosure described and illustrated in the specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of this disclosure and to aid in understanding it, and are not intended to limit the scope of this disclosure. That is, it will be apparent to those skilled in the art that other variations based on the technical concepts of this disclosure can be implemented. Furthermore, one or more of the above embodiments can be used in combination as needed.

[0255] Although specific embodiments have been described in the detailed description of this disclosure, it will be apparent that various modifications and changes can be made thereto without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be defined as limited to the embodiments, but rather as defined by the appended claims and their equivalents.

[0256] Furthermore, the above is disclosed in this publication. Figures 1 to 19 The methods described herein may include methods that combine at least one or more drawings according to various embodiments. For example, Figures 6 to 17 The present disclosure illustrates a beam tracking method according to the present disclosure, and the present disclosure may include methods according to various implementation combinations of at least one or more figures.

Claims

1. A method performed by a terminal in a communication system, the method comprising: The message containing clustering information about the correspondence between clusters and terminal locations is received from the base station via higher-layer signaling, wherein each cluster corresponds to at least one of the locations, and at least one beam pattern is grouped into a cluster within the cluster according to a preset standard. Identify the location of the terminal; Based on clustering information about terminal locations and their corresponding relationships, identify whether the clusters corresponding to the terminal locations have changed; and When the cluster corresponding to the terminal location changes, a Channel State Information (CSI) report including information about the changed cluster is sent to the base station. Channel State Information Reference Signal (CSI-RS) based on changed clustering information is received from the base station, wherein the CSI-RS corresponds to the beam identified based on the beam pattern corresponding to the changed clustering.

2. The method according to claim 1, in, The terminal's location information is identified based on Global Positioning System (GPS) information, and The optimal beam is identified based on at least one of the reference signal received power (RSRP) or channel quality among multiple beams.

3. The method according to claim 1, wherein, The location information of the terminal is identified based on the result of the Reference Signal Received Power (RSRP) of the measured reference signal, and The reference signal is sent by the adjacent base station.

4. The method according to claim 1, in, The received CSI-RS corresponds to the beam associated with the information of the Transmit Configuration Indicator (TCI) status.

5. A method performed by a base station in a communication system, the method comprising: A message containing clustering information, which includes the correspondence between clusters and terminal locations, is sent to the terminal via higher-layer signaling. Each cluster corresponds to at least one of the locations, and at least one beam pattern is grouped into a cluster within the cluster according to a preset standard. If the clustering corresponding to the terminal's location is changed, a Channel State Information (CSI) report including information about the changed clustering is received from the terminal; and Channel State Information Reference Signal (CSI-RS) is sent to the terminal based on information about the changed clusters, wherein the CSI-RS corresponds to a beam identified based on a beam pattern corresponding to the changed clusters.

6. The method according to claim 5, further comprising: The CSI-RS is determined based on information about the Transmission Configuration Indicator (TCI) status associated with the beam.

7. A terminal, the terminal comprising: At least one transceiver; as well as At least one processor, coupled to the at least one transceiver, is configured to: The message containing clustering information about the correspondence between clusters and terminal locations is received from the base station via higher-layer signaling, wherein each cluster corresponds to at least one of the locations, and at least one beam pattern is grouped into a cluster within the cluster according to a preset standard. Identify the location of the terminal; Based on clustering information about terminal locations and their corresponding relationships, identify whether the clusters corresponding to the terminal locations have changed; and In the event of a cluster change corresponding to the terminal location, a Channel State Information (CSI) report including information about the changed cluster is sent to the base station. The base station receives a Channel State Information Reference Signal (CSI-RS) based on information about the changed clustering, wherein the CSI-RS corresponds to a beam identified based on a beam pattern corresponding to the changed clustering.

8. The terminal according to claim 7, in, The terminal's location information is identified based on Global Positioning System (GPS) information, and The optimal beam is identified based on at least one of the reference signal received power (RSRP) or channel quality among multiple beams.

9. The terminal according to claim 7, wherein, The location information of the terminal is identified based on the result of the Reference Signal Received Power (RSRP) of the measured reference signal, and The reference signal is sent by the adjacent base station.

10. The terminal according to claim 7, in, The received CSI-RS corresponds to the beam associated with the information of the Transmit Configuration Indicator (TCI) status.

11. A base station, the base station comprising: At least one transceiver; as well as At least one processor, coupled to the at least one transceiver, is configured to: A message containing clustering information about the correspondence between clusters and terminal locations is sent to the terminal via higher-layer signaling, wherein each cluster corresponds to at least one of the locations, and at least one beam pattern is grouped into a cluster within the cluster according to a preset criterion; If the clustering corresponding to the terminal's location is changed, a Channel State Information (CSI) report including information about the changed clustering is received from the terminal; and Channel State Information Reference Signal (CSI-RS) is sent to the terminal based on information about the changed clusters, wherein the CSI-RS corresponds to a beam identified based on a beam pattern corresponding to the changed clusters.

12. The base station according to claim 11, wherein the at least one processor is further configured to: The CSI-RS is determined based on information about the Transmission Configuration Indicator (TCI) status associated with the beam.

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