Method and apparatus for controlling synchronization signal in wireless communication system applying base station energy saving

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transfer rates. Disclosed in the present disclosure are a method and an apparatus for providing an energy-saving mode of a base station. The base station may specify, for UE, a reference cell that serves as a QCL reference standard for PDCCH DMRSs, in addition to an SCell (SSB-less SCell) with simplified SSB transmission, and inform the UE of the specified reference cell through signaling. The reference cell may be a PCell or a second SCell among cells constituting a carrier aggregation, excluding the SSB-less SCell. The base station may specify an RS that the UE needs to refer to in the reference cell and inform the UE of the specified RS, thereby enabling the UE to determine QCL of the corresponding cell.

Description

Method and device for controlling synchronization signals in a wireless communication system applying base station energy saving

[0001] The present disclosure relates to a communication method of a wireless communication system, and more particularly, to a method and device for energy saving in a wireless communication system.

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

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

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

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

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

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

[0008] The disclosed embodiments aim to provide a device and method capable of effectively providing services in a mobile communication system. In particular, a method and device for efficiently performing base station energy saving operations are disclosed.

[0009] The technical problems to be achieved in the disclosed embodiments are not limited to those mentioned above, and other technical problems not mentioned can be considered by a person having ordinary skill in the art from the various embodiments of the present disclosure described below.

[0010] In order to solve the above problems, the present invention provides a method performed by a terminal of a communication system, comprising: a step of receiving information about a reference cell from a base station; a step of confirming that a first secondary cell (SCell) is an SSB-less SCell; and a step of confirming a second RS having a quasi-co-location (QCL) relationship with a first reference signal (RS) of the first SCell based on the information about the reference cell, wherein the second RS is an RS of a cell indicated by the information about the reference cell.

[0011] Additionally, the second reference signal may be a synchronization signal block (SSB).

[0012] Additionally, the method may further include a step of transmitting terminal capability information supporting SSB-less SCell to the base station.

[0013] Additionally, the maximum receive timing difference (MRTD) required for carrier aggregation (CA) including the SSB-less SCell may be equal to or greater than the MRTD required for intra-band CA and less than the MRTD required for inter-band CA.

[0014] In addition, a method performed by a base station of a communication system includes a step of confirming that a first secondary cell (SCell) is an SSB-less SCell; and a step of transmitting information about a reference cell to a terminal, wherein a first reference signal (RS) of the first SCell and a second RS are in a quasi-co-location (QCL) relationship, and the second RS is an RS of a cell indicated by the information about the reference cell.

[0015] In addition, in a terminal of a communication system, a transmitter / receiver unit; and a control unit configured to receive information about a reference cell from a base station, confirm that a first secondary cell (SCell) is an SSB-less SCell, and confirm a second RS in a quasi-co-location (QCL) relationship with a first reference signal (RS) of the first SCell based on the information about the reference cell, wherein the second RS is an RS of a cell indicated by the information about the reference cell.

[0016] In addition, in a base station of a communication system, a transmitter / receiver unit; and a control unit configured to confirm that a first secondary cell (SCell) is an SSB-less SCell, and to transmit information about a reference cell to a terminal, wherein a first reference signal (RS) of the first SCell and a second RS are in a quasi-co-location (QCL) relationship, and the second RS is an RS of a cell indicated by information about the reference cell.

[0017] The disclosed embodiment provides a device and method for preventing excessive energy consumption of a base station and achieving high energy efficiency in a mobile communication system.

[0018] The effects that can be obtained from the disclosed embodiments are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly derived and understood by a person having ordinary skill in the art based on the detailed description below.

[0019] Figure 1 is a diagram illustrating an example of the basic structure of the time-frequency resource domain of a 5G system.

[0020] FIG. 2 is a diagram illustrating an example of a time domain mapping structure and beam sweeping operation of a synchronization signal of a 5G system.

[0021] Figure 3 is a diagram illustrating an example of a random access procedure of a 5G system.

[0022] FIG. 4 is a diagram illustrating an example of a procedure in which a terminal reports terminal capability information to a base station in a 5G system.

[0023] Fig. 5 is a diagram illustrating an example of base station beam allocation according to TCI state settings.

[0024] FIG. 6 is a diagram illustrating an example of an allocation method for a PDCCH beam.

[0025] FIG. 7 is a diagram illustrating an example of a TCI indication MAC CE signaling structure for the PDCCH DMRS.

[0026] Figure 8 is a diagram illustrating an example of CORESET and search space beam settings.

[0027] Figure 9 is a diagram illustrating an example of configuring a 5G system by combining three constituent carriers for each of uplink and downlink.

[0028] FIG. 10 is a diagram illustrating an example of a QCL determination method of a terminal when the terminal does not receive a MAC CE activation command for a TCI state of an SCell from a base station according to the first embodiment.

[0029] Fig. 11 is a drawing showing an example of an operation according to the second embodiment.

[0030] Fig. 12 is a diagram showing an example of EPRE settings for downlink signals in a 5G system.

[0031] FIG. 13 is a diagram illustrating an example of a terminal procedure according to one embodiment of the present disclosure.

[0032] FIG. 14 is a diagram illustrating an example of a base station procedure according to one embodiment of the present disclosure.

[0033] FIG. 15 is a diagram illustrating an example of a terminal transmitting and receiving device in a wireless communication system according to one embodiment of the present disclosure.

[0034] FIG. 16 is a block diagram illustrating an example of a structure of a terminal according to one embodiment of the present disclosure.

[0035] FIG. 17 is a block diagram illustrating an example of a structure of a base station according to one embodiment of the present disclosure.

[0036] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. Furthermore, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on their functions in the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0037] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0038] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0039] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0040] Here, the term '~ unit' used in this embodiment means software or hardware components such as FPGA (field programmable gate array) or ASIC (application specific integrated circuit), and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium or may be configured to play one or more processors. Therefore, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within a device or secure multimedia card. In addition, in an embodiment, the '~parts' may include one or more processors.

[0041] In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Hereinafter, embodiments of the present disclosure will be described with reference to the attached drawings.

[0042] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc. are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0043] In the following description, the terms "physical channel" and "signal" may be used interchangeably with data or control signals. For example, while PDSCH (physical downlink shared channel) refers to a physical channel through which data is transmitted, PDSCH may also be used to refer to data. That is, in the present disclosure, the expression "transmitting a physical channel" may be interpreted equivalently to the expression "transmitting data or a signal through a physical channel."

[0044] Hereinafter, in the present disclosure, upper layer signaling (or upper signaling, upper layer signaling) refers to a signal transmission method in which a base station transmits a signal to a terminal using a downlink data channel of a physical layer, or from a terminal to a base station using an uplink data channel of a physical layer. Upper layer signaling may be referred to as RRC (radio resource control) signaling, PDCP signaling, or MAC (media access control) control element (CE).

[0045] For convenience of explanation below, this disclosure uses terms and names defined in the 3GPP NR (New Radio, or 5th generation mobile communication standard) specifications. However, this disclosure is not limited to the above terms and names, and embodiments of this disclosure may be applied to other communication systems with similar technical backgrounds or channel types. For example, this may include LTE or LTE-A mobile communication and mobile communication technologies developed after 5G. Therefore, embodiments of this disclosure may be applied to other communication systems with some modifications within a scope that does not significantly deviate from the scope of this disclosure, as determined by a person skilled in the art.

[0046] Hereinafter, a base station is an entity that performs resource allocation for a terminal, and may be at least one of a gNodeB, a gNB, an eNodeB, an eNB, a NodeB, a BS (base station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (user equipment), an MS (mobile station), a cellular phone, a smartphone, a computer, an IoT device, a sensor, or a multimedia system capable of performing a communication function. Of course, the present invention is not limited to the examples described.

[0047] In the following description of the present disclosure, upper layer signaling may be signaling corresponding to at least one or a combination of one or more of the following signaling.

[0048] - MIB (master information block)

[0049] - SIB (system information block) or SIB

[0050] - RRC (radio resource control)

[0051] - MAC (medium access control) CE (control element)

[0052] In addition, L1 signaling may be signaling corresponding to at least one or a combination of one or more signaling methods using the physical layer channel or signaling below.

[0053] - PDCCH (physical downlink control channel)

[0054] - DCI (downlink control information)

[0055] - UE-specific DCI

[0056] - Group common DCI

[0057] - Common DCI

[0058] - Scheduling DCI (e.g. DCI used for scheduling downlink or uplink data)

[0059] - Non-scheduled DCI (e.g. DCI not intended for scheduling downlink or uplink data)

[0060] - PUCCH (physical uplink control channel)

[0061] - UCI (uplink control information)

[0062] The term “slot” used in the present disclosure below is a general term that may refer to a specific time unit corresponding to a transmit time interval (TTI), and may specifically mean a slot used in a 5G NR system, or a slot or subframe used in a 4G LTE system.

[0063] To handle the explosive growth in mobile data traffic, 5G (5G), the next-generation communication system after LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)) and LTE-A (LTE-Advanced or E-UTRA Evolution), is being developed. th The initial standards for the 5G (New Radio Access Technology Generation) system or New Radio access technology (NR) have been completed. While existing mobile communication systems have focused on conventional voice / data communications, the 5G system aims to satisfy various services and requirements, such as enhanced mobile broadband (eMBB) services to improve existing voice / data communications, ultra-reliable and low latency communication (URLLC) services for high reliability and ultra-low latency services, and massive machine type communication (MTC) services that support large-scale machine-type communication.

[0064] While the transmission bandwidth of existing LTE and LTE-A systems per single carrier is limited to a maximum of 20MHz, the 5G system aims to utilize a much wider ultra-wide bandwidth to provide ultra-high-speed data services of up to several Gbps. Accordingly, the 5G system is considering ultra-high frequency bands ranging from several GHz up to 100 GHz as candidate frequencies, where securing ultra-wide bandwidth frequencies is relatively easy. Additionally, wide bandwidth frequencies for the 5G system can be secured through frequency reallocation or allocation among frequency bands ranging from several hundred MHz to several GHz used in existing mobile communication systems.

[0065] Ultra-high frequency radio waves, sometimes called millimeter waves (mmWave), have wavelengths on the order of millimeters. However, in ultra-high frequency bands, path loss increases proportionally to the frequency band, reducing the coverage of mobile communication systems.

[0066] To overcome the drawback of reduced coverage in ultra-high frequency bands, beamforming technology is applied, which uses multiple antennas to focus the radiated energy of radio waves toward a predetermined target point and increase the transmission range of radio waves. In other words, a signal to which beamforming technology is applied has a relatively narrow beam width, and the radiated energy is concentrated within the narrowed beam width, increasing the transmission range. Beamforming technology can be applied to both the transmitter and receiver. In addition to increasing coverage, beamforming technology also has the effect of reducing interference in areas outside the beamforming direction. For beamforming technology to operate properly, accurate measurement and feedback methods of the transmission / reception beams are required. Beamforming technology can be applied to control channels or data channels that correspond one-to-one between a given terminal and a base station. Additionally, beamforming technology can be applied to common signals transmitted by a base station to multiple terminals within a system, such as synchronization signals, physical broadcast channels (PBCH), control channels for transmitting system information (SI), and data channels, to increase coverage. When beamforming technology is applied to common signals, beam sweeping technology, which transmits signals by changing the beam direction, is additionally applied so that the common signal can reach terminals located at any location within the cell.

[0067] Another requirement for 5G systems is ultra-low latency services, with transmission delays of approximately 1ms between transmitters and receivers. One way to reduce transmission delay is to design a frame structure based on a short TTI (Time To Time Interval), compared to LTE and LTE-A. A TTI is the basic time unit for scheduling, and the TTI of existing LTE and LTE-A systems is 1ms, corresponding to the length of one subframe. For example, in 5G systems, based on the short TTI required to meet the requirements for ultra-low latency services, shorter TTIs of 0.5ms, 0.25ms, and 0.125ms are possible, even shorter than those of existing LTE and LTE-A systems.

[0068] Figure 1 is a diagram illustrating an example of the basic structure of the time-frequency resource domain of a 5G system. That is, Figure 1 is a diagram illustrating the basic structure of the time-frequency resource domain, which is a radio resource domain in which data or control channels of a 5G system are transmitted.

[0069] Referring to Figure 1, the horizontal axis in Figure 1 represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain of the 5G system is an OFDM (orthogonal frequency division multiplexing) symbol. (102) symbols are gathered together to form one slot (106), A plurality of slots can be gathered to form a subframe (105). The length of one subframe (105) is 1.0 ms, and 10 subframes can be gathered to form a 10 ms frame (114). The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the entire system transmission band is a total of N BW It can be composed of (104) subcarriers.

[0070] The basic unit of resources in the time-frequency domain is a resource element (RE) (112), which can be represented by an OFDM symbol index and a subcarrier index. A resource block (RB or physical resource block, PRB) in the frequency domain It can be defined as (110) consecutive subcarriers. In 5G systems, = 12, and the data rate can increase in proportion to the number of RBs scheduled to the terminal.

[0071] In a 5G system, a base station can map data in RB units and perform scheduling on RBs, which typically constitute a slot for a given terminal. That is, in a 5G system, the basic time unit for scheduling may be a slot, and the basic frequency unit for scheduling may be an RB.

[0072] Number of OFDM symbols It is determined by the length of the cyclic prefix (CP) added to each symbol to prevent interference between symbols. For example, if the normal CP is applied, = 14, when extended CP is applied = 12 can be. Extended CP is applied to a system with a relatively long transmission distance than the general CP, and can maintain orthogonality between symbols. In the case of the general CP, since the ratio of the CP length to the symbol length is maintained at a constant value, the overhead due to the CP can be maintained constant regardless of the subcarrier spacing (SCS). That is, if the subcarrier spacing is small, the symbol length becomes longer, and thus the CP length can also become longer. Conversely, if the subcarrier spacing is large, the symbol length becomes shorter, and thus the CP length can be reduced. The symbol length and CP length can be inversely proportional to the subcarrier spacing.

[0073] In 5G systems, various frame structures can be supported by adjusting the subcarrier spacing to meet diverse services and requirements. For example,

[0074] - From the perspective of the operating frequency band, the larger the subcarrier spacing, the more advantageous it is for recovering phase noise in the high-frequency band.

[0075] - From the perspective of transmission time, if the subcarrier spacing is large, the symbol length in the time domain becomes shorter, and consequently, the slot length becomes shorter, which is advantageous for supporting ultra-low delay services such as URLLC.

[0076] - From a cell size perspective, a longer CP length allows for larger cells to be supported, so a smaller subcarrier spacing allows for relatively larger cells to be supported. In mobile communications, a cell is a concept that refers to the area covered by a single base station.

[0077] Subcarrier spacing, CP length, and other information are essential for OFDM transmission and reception. For smooth transmission and reception, the base station and terminal must recognize these values ​​as common values. Table 1 shows the relationship between the subcarrier spacing configuration (μ), subcarrier spacing (f), and CP length supported by 5G systems.

[0078] μ Cyclic prefix015Normal130Normal260Normal, Extended3120Normal4240Normal

[0079] Table 2 shows the number of symbols per slot for each subcarrier spacing setting (μ) for the general CP. ), number of slots per frame ( ), number of slots per subframe ( ) is indicated.

[0080] μ 01410111420221440431480841416016

[0081] Table 3 shows the number of symbols per slot for each subcarrier spacing setting (μ) for the extended CP. ), number of slots per frame ( ), number of slots per subframe ( ) appears.

[0082] μ 212404

[0083] In the initial phase of 5G system deployment, coexistence or dual-mode operation with existing LTE and / or LTE-A (hereinafter referred to as LTE / LTE-A) systems is expected. This allows existing LTE / LTE-A systems to provide stable system operation to terminals, while the 5G system can provide enhanced services to terminals. Therefore, the 5G system's frame structure must at least include the LTE / LTE-A frame structure or essential parameter set (subcarrier spacing = 15 kHz).

[0084] For example, comparing a frame structure with a subcarrier spacing setting μ=0 (hereinafter referred to as frame structure A) and a frame structure with a subcarrier spacing setting μ=1 (hereinafter referred to as frame structure B), compared to frame structure A, frame structure B shows that the subcarrier spacing and RB size are twice as large, and the slot length and symbol length are twice as small. In the case of frame structure B, two slots can constitute one subframe, and 20 subframes can constitute one frame.

[0085] Generalizing the frame structure of a 5G system provides high scalability by ensuring that essential parameters—subcarrier spacing, CP length, and slot length—have integer multiple relationships for each frame structure. Furthermore, a fixed-length subframe of 1 ms can be defined to represent a reference time unit independent of the frame structure.

[0086] The frame structure of a 5G system can be applied to various scenarios. From a cell size perspective, a longer CP length can support larger cells, so frame structure A can support relatively larger cells than frame structure B. From an operating frequency band perspective, a larger subcarrier spacing is advantageous for recovering phase noise in high-frequency bands, so frame structure B can support relatively higher operating frequencies than frame structure A. From a service perspective, a shorter slot length, which is the basic time unit of scheduling, is advantageous for supporting ultra-low-latency services such as URLLC, so frame structure B can be relatively more suitable for URLLC services than frame structure A.

[0087] In the following description of the present disclosure, uplink (UL) may refer to a wireless link through which a terminal transmits data or a control signal to a base station, and downlink (DL) may refer to a wireless link through which a base station transmits data or a control signal to a terminal.

[0088] In the initial access phase, when a terminal first accesses the system, the terminal can synchronize downlink time and frequency from a synchronization signal transmitted by a base station through cell search, and obtain a cell identifier (cell ID). Then, the terminal can receive a physical broadcast channel (PBCH) using the obtained cell ID, and obtain MIB, which is essential system information, from the PBCH. Additionally, the terminal can obtain cell-common transmission and reception-related control information by receiving system information (SI or system information block, SIB) transmitted by the base station. The cell-common transmission and reception-related control information may include random access-related control information, paging-related control information, and common control information for various physical channels.

[0089] The synchronization signal serves as a reference for cell search, and subcarrier spacing can be applied to suit channel conditions such as phase noise for each frequency band. For data channels or control channels, as described above, different subcarrier spacings can be applied depending on the service type to support various services.

[0090] FIG. 2 is a diagram illustrating an example of a time domain mapping structure and beam sweeping operation of a synchronization signal of a 5G system.

[0091] For the purpose of explanation, the following components can be defined:

[0092] - PSS (primary synchronization signal): This signal serves as the basis for DL ​​time / frequency synchronization and provides some cell ID information.

[0093] - SSS (secondary synchronization signal): Serves as a reference for DL ​​time / frequency synchronization and provides some remaining information, including the cell ID. Additionally, it can serve as a reference signal for PBCH demodulation.

[0094] - PBCH: Provides the MIB, essential system information required for the terminal's data and control channel transmission and reception. The MIB may include search space-related control information indicating radio resource mapping information for the control channel, scheduling control information for a separate data channel transmitting system information, and the SFN (system frame number), a frame-level index that serves as a timing reference.

[0095] - SS / PBCH block (synchronization signal / PBCH block or SSB): An SS / PBCH block consists of N OFDM symbols and is a combination of PSS, SSS, PBCH, etc. In a system where beam sweeping technology is applied, the SS / PBCH block is the minimum unit to which beam sweeping is applied. In a 5G system, N can be 4. The base station can transmit up to L SS / PBCH blocks, and the L SS / PBCH blocks are mapped within a half frame (0.5 ms). The L SS / PBCH blocks are periodically repeated in units of a predetermined period P. The period P can be notified to the terminal through signaling by the base station. If there is no separate signaling for the period P, the terminal applies a pre-agreed default value. Each SS / PBCH block has an SS / PBCH block index from 0 to a maximum of L-1, and the terminal can know the SS / PBCH block index through SS / PBCH detection.

[0096] Referring to FIG. 2, beam sweeping is applied to SS / PBCH block units over time. In the example of FIG. 2, terminal 1 (205) receives an SS / PBCH block using a beam radiated in the direction of #d0 (203) by beamforming applied to SS / PBCH block #0 at time t1 (201). Terminal 2 (206) receives an SS / PBCH block using a beam radiated in the direction of #d4 (204) by beamforming applied to SS / PBCH block #4 at time t2 (202). The terminal can obtain an optimal synchronization signal through a beam radiated from the base station in the direction where the terminal is located. For example, terminal 1 (205) may have difficulty obtaining time / frequency synchronization and essential system information from an SS / PBCH block through a beam radiated in the direction of #d4, which is far from the location of terminal 1.

[0097] In addition to the initial connection procedure, the UE may also receive SS / PBCH blocks to determine whether the radio link quality of the current cell is maintained at a certain level. Furthermore, during a handover procedure, in which the UE moves from the current cell to a neighboring cell, the UE may receive SS / PBCH blocks from the neighboring cell to determine the radio link quality of the neighboring cell and obtain time / frequency synchronization with the neighboring cell.

[0098] After the terminal acquires MIB and system information from the base station through the initial access procedure, the terminal can perform a random access procedure to transition the link with the base station to the connected state (or RRC_CONNECTED state). Upon completion of the random access procedure, the terminal transitions to the connected state, enabling one-to-one communication between the base station and the terminal. The random access procedure is described in detail below with reference to FIG. 3.

[0099] FIG. 3 is a diagram illustrating an example of a random access procedure of a 5G system. FIG. 3 illustrates an example of a random access procedure, and the present disclosure is not limited thereto. In addition, the present disclosure is not limited to the 4-step random access procedure illustrated in FIG. 3, and can also be applied to a 2-step random access procedure (transmitting and receiving message A (a message including information corresponding to message 1 and message 3) and transmitting and receiving message B (a message including information corresponding to message 2 and message 4)).

[0100] Referring to FIG. 3, in the first step (310) of the random access procedure, the terminal transmits a random access preamble to the base station. The random access preamble, which is the first transmission message of the terminal in the random access procedure, may be referred to as message 1. The base station can measure the transmission delay value between the terminal and the base station from the random access preamble and synchronize the uplink. At this time, the terminal can arbitrarily select which random access preamble to use within the random access preamble set given in advance by system information. In addition, the initial transmission power of the random access preamble can be determined according to the path loss between the terminal and the base station measured by the terminal. In addition, the terminal can determine the transmission beam direction of the random access preamble from the synchronization signal received from the base station and transmit the random access preamble.

[0101] In the second step (320), the base station transmits an uplink transmission timing adjustment command to the terminal based on the transmission delay value measured from the random access preamble received in the first step (310). Additionally, the base station may transmit uplink resource information and a power control command to be used by the terminal as scheduling information. The scheduling information may include control information regarding the terminal's uplink transmission beam.

[0102] If the terminal does not receive the random access response (RAR, or message 2), which is scheduling information for message 3, from the base station within a predetermined time in the second step (320), the first step (310) can be performed again. If the first step (310) is performed again, the terminal can increase the probability of the base station receiving the random access preamble by transmitting it while increasing the transmission power of the random access preamble by a predetermined step (power ramping).

[0103] In the third step (330), the terminal transmits uplink data (message 3) including its terminal ID to the base station through an uplink data channel (physical uplink shared channel, PUSCH) using the uplink resources allocated in the second step (320). The transmission timing of the uplink data channel for transmitting Message 3 may follow the timing control command received from the base station in the second step (320). In addition, the transmission power of the uplink data channel for transmitting Message 3 may be determined in consideration of the power control command received from the base station in the second step (320) and the power ramping value of the random access preamble. The uplink data channel for transmitting Message 3 may mean the first uplink data signal that the terminal transmits to the base station after transmitting the random access preamble.

[0104] In step 4 (340), if the base station determines that the terminal has performed random access without collision with other terminals, it transmits data (message 4) including the ID of the terminal that transmitted uplink data in step 3 (330) to the terminal. If the terminal receives the signal transmitted by the base station in step 4 (340) from the base station, it can determine that the random access has been successful. In addition, the terminal can transmit HARQ-ACK information indicating whether message 4 was successfully received to the base station through an uplink control channel (physical uplink control channel, PUCCH).

[0105] If the data transmitted by the terminal in step 3 (330) collides with data from another terminal, causing the base station to fail to receive a data signal from the terminal, the base station may not transmit any more data to the terminal. Accordingly, if the terminal fails to receive the data transmitted from the base station in step 4 (340) within a certain period of time, it may determine that the random access procedure has failed and restart from step 1 (310).

[0106] Upon successful completion of the random access procedure, the terminal transitions to the connected state, enabling one-to-one communication between the base station and the terminal. The base station receives UE capability information from the connected terminal and can adjust scheduling based on the UE capability information. Through UE capability information, the terminal can inform the base station of whether it supports a given function and the maximum allowable value of the function it supports. Therefore, the UE capability information reported by each terminal to the base station may vary.

[0107] FIG. 4 is a diagram illustrating an example of a procedure in which a terminal reports terminal capability information to a base station in a 5G system.

[0108] Referring to FIG. 4, at step 410, the base station (402) can transmit a UE capability information request message to the terminal (401). In response to the base station's request for UE capability information, the terminal transmits UE capability information to the base station at step 420.

[0109] For example, a terminal may report UE capability information including at least a portion of the following control information to a base station as UE capability information.

[0110] - Control information related to frequency bands supported by the terminal

[0111] - Control information related to channel bandwidth supported by the terminal

[0112] - Control information related to the maximum modulation method supported by the terminal

[0113] - Control information related to the maximum number of beams supported by the terminal

[0114] - Control information related to the maximum number of layers supported by the terminal

[0115] - Control information related to CSI reporting supported by the terminal

[0116] - Control information on whether the terminal supports frequency hopping

[0117] - Bandwidth-related control information when supporting carrier aggregation (CA)

[0118] - Control information on whether cross carrier scheduling is supported when carrier aggregation is supported.

[0119] Next, we will specifically explain downlink control information (DCI) in the 5G system.

[0120] In a 5G system, scheduling information for uplink data (or physical uplink data channel (PUSCH)) or downlink data (or physical downlink data channel (PDSCH)) can be transmitted from a base station to a terminal via DCI. The terminal can monitor a DCI format for fallback and a DCI format for non-fallback for the PUSCH or PDSCH. The fallback DCI format can be composed of fixed fields predefined between the base station and the terminal, and the non-fallback DCI format can include configurable fields.

[0121] DCI can be transmitted over the physical downlink control channel (PDCCH) after going through the channel coding and modulation process. A cyclic redundancy check (CRC) is attached to the DCI message payload, and the CRC can be scrambled with a radio network temporary identifier (RNTI) corresponding to the identity of the UE. Different RNTIs can be used depending on the purpose of the DCI message, such as UE-specific data transmission, power control command, or random access response. That is, the RNTI is not transmitted explicitly, but is included in the CRC calculation process. When the UE receives a DCI message transmitted on the PDCCH, it verifies the CRC using the assigned RNTI. If the CRC verification result is correct, the UE can determine that the message was transmitted to the UE.

[0122] For example, a DCI scheduling a PDSCH for system information may be scrambled with SI-RNTI. A DCI scheduling a PDSCH for a RAR message may be scrambled with RA-RNTI. A DCI scheduling a PDSCH for a paging message may be scrambled with P-RNTI. A DCI notifying a slot format indicator (SFI) may be scrambled with SFI-RNTI. A DCI notifying a transmit power control (TPC) may be scrambled with TPC-RNTI. A DCI scheduling a UE-specific PDSCH or PUSCH may be scrambled with C-RNTI (cell RNTI).

[0123] The base station can operate by applying a predetermined DCI format depending on whether the DCI is scheduling information for downlink data (downlink assignment) for the terminal to be scheduled, scheduling information for uplink data (uplink grant), or DCI for purposes other than data scheduling, such as power control.

[0124] The base station can transmit downlink data to the terminal via the Physical Downlink Data Channel (PDSCH), a physical channel for downlink data transmission. Scheduling information, such as the specific mapping location in the time and frequency domains of the PDSCH, modulation scheme, HARQ-related control information, and power control information, can be communicated to the terminal by the base station via DCI related to downlink data scheduling information, among the DCIs transmitted via the PDCCH.

[0125] A terminal can transmit uplink data to a base station via the PUSCH, a physical channel for uplink data transmission. Scheduling information, such as the specific mapping location in the time and frequency domains of the PUSCH, modulation scheme, HARQ-related control information, and power control information, can be provided to the terminal by the base station via DCI related to uplink data scheduling information, among the DCIs transmitted via the PDCCH.

[0126] The time-frequency resources to which the PDCCH is mapped are called control resource sets (CORESETs). A CORESET can be configured for all or part of the frequency resources of the bandwidth supported by the UE in the frequency domain. In the time domain, it can be configured with one or more OFDM symbols, which can be defined as the CORESET length (control resource set duration). The base station can configure one or more CORESETs to the UE through higher layer signaling (e.g., system information, MIB, RRC signaling). Configuring a CORESET to the UE may mean providing information such as a CORESET identifier, the frequency location of the CORESET, and the symbol length of the CORESET. The information that the base station provides to the UE to configure the CORESET may include at least some of the information included in Table 4.

[0127] ControlResourceSet ::= SEQUENCE {controlResourceSetId ControlResourceSetId,(CORESET identifier)frequencyDomainResources BIT STRING (SIZE (45)),(frequency domain resources)duration INTEGER (1..maxCoReSetDuration),(CORESET length)cce-REG-MappingType CHOICE {(CCE-to-REG mapping type)interleaved SEQUENCE {reg-BundleSize ENUMERATED {n2, n3, n6},(REG bundle size)interleaverSize ENUMERATED {n2, n3, n6},(interleaver size)shiftIndex INTEGER(0..maxNrofPhysicalResourceBlocks-1) OPTIONAL -- Need S(interleaver shift)},nonInterleaved NULL},precoderGranularity ENUMERATED {sameAsREG-bundle, allContiguousRBs},(precoding unit)tci-StatesPDCCH-ToAddList SEQUENCE(SIZE (1..maxNrofTCI-StatesPDCCH)) OF TCI-StateId OPTIONAL, -- Cond NotSIB1-initialBWP(QCL configuration information)tci-StatesPDCCH-ToReleaseList SEQUENCE(SIZE (1..maxNrofTCI-StatesPDCCH)) OF TCI-StateId OPTIONAL, -- Cond NotSIB1-initialBWP(QCL configuration information)tci-PresentInDCI ENUMERATED {enabled} OPTIONAL, -- Need S(QCL indicator configuration information in DCI)pdcch-DMRS-ScramblingID INTEGER (0..65535) OPTIONAL, -- Need S(PDCCH DMRS scrambling identifier)}

[0128] CORESET is in the frequency domain It can be composed of RBs and in the time domain ∈{1,2,3} symbols. The PDCCH may be composed of one or more control channel elements (CCEs). One CCE may be composed of six resource element groups (REGs), and a REG may be defined as one RB during one OFDM symbol. Within one CORESET, REGs may be indexed in time-first order, starting with REG index 0 from the first OFDM symbol of the CORESET, the lowest RB.

[0129] Interleaved and non-interleaved transmission methods for PDCCH can be supported. The base station can configure whether to use interleaved or non-interleaved transmission for each CORESET to the terminal through upper layer signaling. Interleaving can be performed in units of REG bundles. A REG bundle can be defined as a set of one or more REGs. The terminal can determine the CCE-to-REG mapping method in the corresponding CORESET based on whether to use interleaved or non-interleaved transmission as configured by the base station, as shown in Table 5 below.

[0130] [Table 5]

[0131]

[0132] The base station can inform the terminal of configuration information such as which symbol within the slot the PDCCH is mapped to and the transmission cycle through signaling.

[0133] The search space of the PDCCH is described as follows. The number of CCEs required to transmit the PDCCH can be 1, 2, 4, 8, or 16 depending on the aggregation level (AL), and different numbers of CCEs can be used for link adaptation of the downlink control channel. For example, when AL=L, a single downlink control channel can be transmitted through L CCEs. The UE performs blind decoding, which detects a signal without knowing information about the downlink control channel. For this purpose, a search space representing a set of CCEs can be defined. The search space is a set of downlink control channel candidates consisting of CCEs that the UE should attempt to decode at a given aggregation level. Since there are various aggregation levels that create a single group with 1, 2, 4, 8, or 16 CCEs, the UE can have multiple search spaces. A search space set can be defined as the set of search spaces at all established aggregation levels.

[0134] Search spaces can be categorized into a common search space (CSS) and a UE-specific search space (USS). A certain group of UEs, or all UEs, can scan the common search space of the PDCCH to receive cell-common control information, such as dynamic scheduling for system information or paging messages. For example, a UE can receive scheduling allocation information for the PDSCH for system information reception by scanning the common search space of the PDCCH. In the case of the common search space, since a certain group of UEs, or all UEs, must receive the PDCCH, it can be defined as a set of pre-arranged CCEs. UE-specific scheduling allocation information for the PDSCH or PUSCH can be received by scanning the UE-specific search space of the PDCCH. The UE-specific search space can be defined UE-specifically as a function of the UE's identity and various system parameters.

[0135] The base station can set the search space configuration information of the PDCCH to the terminal through higher layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station can set the number of PDCCH candidates in each aggregation level L, the monitoring period for the search space, the monitoring occasion for each symbol within the slot for the search space, the search space type (common search space or terminal-specific search space), the combination of DCI format and RNTI to be monitored in the corresponding search space, the CORESET index to be monitored for the search space, etc. to the terminal. For example, the parameters for the search space for the PDCCH may include information such as that shown in Table 6 below.

[0136] SearchSpace ::= SEQUENCE {searchSpaceId SearchSpaceId,(search space identifier)controlResourceSetId ControlResourceSetId OPTIONAL, -- Cond SetupOnly(CORESET identifier)monitoringSlotPeriodicityAndOffset CHOICE {(monitoring slot period and offset)sl1 NULL,sl2 INTEGER (0..1),sl4 INTEGER (0..3),sl5 INTEGER (0..4),sl8 INTEGER (0..7),sl10 INTEGER (0..9),sl16 INTEGER (0..15),sl20 INTEGER (0..19),sl40 INTEGER (0..39),sl80 INTEGER (0..79),sl160 INTEGER (0..159),sl320 INTEGER (0..319),sl640 INTEGER (0..639),sl1280 INTEGER (0..1279),sl2560 INTEGER (0..2559)} OPTIONAL, -- Cond Setupduration INTEGER (2..2559) OPTIONAL, -- Need R(모니터링 가라)monitoringSymbolsWithinSlot BIT STRING (SIZE (14)) OPTIONAL, -- Cond Setup(슬롘 내 모리스 심보운지)nrofCandidates SEQUENCE {(집성 별별 PDCCH 이리군 수) aggregationLevel1 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel2 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel4 ENUMERATED { n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel8 ENUMERATED { n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel16 ENUMERATED { n0, n1, n2, n3, n4,n5,n6,n8}} OPTIONAL. Need RaggregationLevel4 ENUMERATED {n1, n2} OPTIONAL, -- Need RaggregationLevel8 ENUMERATED {n1, n2} OPTIONAL, -- Need RaggregationLevel16 ENUMERATED {n1, n2} OPTIONAL -- Need R},...} OPTIONAL, -- Need Rdci-Format2-1 SEQUENCE {...} OPTIONAL, -- Need Rdci-Format2-2 SEQUENCE {...} OPTIONAL, -- Need Rdci-Format2-3 SEQUENCE {dummy1 ENUMERATED {sl1, sl2, sl4, sl5, sl8, sl10, sl16, sl20} OPTIONAL, -- Cond Setupdummy2 ENUMERATED {n1, n2},...} OPTIONAL -- Need R},ue-Specific SEQUENCE {(Terminal-Specific Search Space)dci-Formats ENUMERATED {formats0-0-And-1-0, formats0-1-And-1-1},...,}} OPTIONAL -- Cond Setup2}.

[0137] Depending on the configuration information, the base station may configure one or more search space sets for the terminal. In some embodiments, the base station may configure search space set 1 and search space set 2 for the terminal. In search space set 1, the terminal may be configured to monitor DCI format A scrambled with X-RNTI in a common search space, and in search space set 2, the terminal may be configured to monitor DCI format B scrambled with Y-RNTI in a terminal-specific search space.

[0138] According to the configuration information, one or more search space sets may exist in a common search space or a terminal-specific search space. For example, search space set #1 and search space set #2 may be configured as a common search space, and search space set #3 and search space set #4 may be configured as terminal-specific search spaces.

[0139] In a common search space, a terminal can monitor the following combinations of DCI formats and RNTIs, although these are not limited to the following examples.

[0140] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

[0141] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0142] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0143] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0144] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0145] In a terminal-specific search space, a terminal can monitor the following combinations of DCI formats and RNTIs, although these are not limited to the following examples.

[0146] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0147] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0148] RNTIs may follow the following definitions and uses:

[0149] C-RNTI (cell RNTI): For terminal-specific PDSCH or PUSCH scheduling purposes.

[0150] TC-RNTI (temporary cell RNTI): For terminal-specific PDSCH scheduling purposes

[0151] CS-RNTI (configured scheduling RNTI): Used for semi-static terminal-specific PDSCH scheduling.

[0152] RA-RNTI (random access RNTI): Used for PDSCH scheduling in the random access phase.

[0153] P-RNTI (paging RNTI): Used for scheduling PDSCH where paging is transmitted.

[0154] SI-RNTI (system information RNTI): Used for scheduling PDSCH where system information is transmitted.

[0155] INT-RNTI (interruption RNTI): Used to indicate whether PDSCH is punctured.

[0156] TPC-PUSCH-RNTI (transmit power control for PUSCH RNTI): Used to indicate power control commands for PUSCH.

[0157] TPC-PUCCH-RNTI (transmit power control for PUCCH RNTI): Used to indicate power control commands for PUCCH.

[0158] TPC-SRS-RNTI (transmit power control for SRS RNTI): Used to indicate power control commands for SRS.

[0159] The DCI formats described above can follow the definitions shown in Table 7 below.

[0160] DCI formatUsage0_0Scheduling of PUSCH in one cell0_1Scheduling of PUSCH in one cell1_0Scheduling of PDSCH in one cell1_1Scheduling of PDSCH in one cell2_0Notifying a group of UEs of the slot format2_1Notifying a group of UEs of the PRB(s) and OFDM symbol(s) where UE may assume no transmission is intended for the UE2_2Transmission of TPC commands for PUCCH and PUSCH2_3Transmission of a group of TPC commands for SRS transmissions by one or more UEs

[0161] In a 5G system, the search space of aggregation level L in CORESET p and search space set s can be expressed as in the following mathematical expression 1.

[0162] [Mathematical Formula 1]

[0163]

[0164] - L: Integration level

[0165] - n CI : Carrier Index

[0166] - n CCE,p : Total number of CCEs present in CORESET p

[0167] - : slot index

[0168] - : Number of PDCCH candidates for aggregation level L

[0169] - = 0, ..., -1: PDCCH candidate index of aggregation level L

[0170] - l = 0, ..., L -1

[0171] - , Y p,-1 = nRNTI≠0, A p = 39827 for p mod 3 = 0, A p = 39829 for p mod 3 = 1, A p = 39839 for p mod 3 = 2, D= 65537

[0172] - n RNTI : Terminal identifier

[0173] The value can be 0 for a common search space.

[0174] In the case of a terminal-specific search space, the value may correspond to a value that changes depending on the terminal's identity (C-RNTI or ID set to the terminal by the base station) and the time index.

[0175] Below, a method for measuring and reporting channel status in a 5G communication system is described in detail.

[0176] Channel state information (CSI) may include the following information:

[0177] - Channel quality indicator (CQI): CQI index indication information consisting of a modulation method and coding rate that satisfies the minimum reception error rate of the predefined PDSCH.

[0178] - Precoding matrix indicator (PMI): Precoding matrix indicator information selected by the terminal.

[0179] - CRI (CSI-RS (channel state information reference signal) resource indicator): CSI-RS information measured by the terminal

[0180] - RI (rank indicator): Rank indication information selected by the terminal

[0181] - LI (layer indicator): Indication information for the best layer among the precoding matrices reported by the terminal.

[0182] - SSBRI (SS / PBCH block resource indicator): SSB information measured by the terminal

[0183] - L1-RSRP (reference signal received power): L1 RSRP information measured by the terminal

[0184] The base station can control time and frequency resources for the aforementioned CSI measurement and reporting of the terminal.

[0185] For CSI measurement and reporting operations, 'aperiodic', 'semi-persistent', and 'periodic' methods are supported, and the base station can set which method to use to the terminal through signaling. The semi-persistent CSI reporting method supports 'semi-PersistentOnPUCCH' and 'semi-PersistentOnPUSCH'. In the case of periodic or semi-persistent CSI reporting methods, the terminal can be configured with PUCCH or PUSCH resources to transmit CSI from the base station through upper layer signaling. The period and slot offset of the PUCCH or PUSCH resources to transmit CSI can be given by setting the subcarrier spacing of the uplink (UL) bandwidth part where the CSI report is configured to be transmitted. In the case of the aperiodic CSI reporting method, the terminal can schedule PUSCH resources for transmitting CSI from the base station through L1 signaling (DCI format 0_1 ​​described above).

[0186] Aperiodic CSI reporting of a terminal can use PUSCH, periodic CSI reporting can use PUCCH, and semi-persistent CSI reporting can be performed using PUSCH when triggered or activated by DCI, or PUCCH after activation by MAC CE.

[0187] Aperiodic CSI reporting may be triggered by the “CSI request” field of the aforementioned DCI format 0_1 ​​corresponding to the scheduling DCI for PUSCH.

[0188] In a wireless communication system, one or more different antenna ports (or one or more channels, signals, and combinations thereof, but for convenience, they will be referred to as different antenna ports in the following description of the present disclosure) can be associated with each other by a QCL (quasi co-location) setting as shown in Table 8 below. The TCI state is to notify the QCL relationship between physical channel A (or the demodulation reference signal (DMRS) of the physical channel A) and another RS ​​or channel B. When a reference antenna port A (reference RS #A) and another target antenna port B (target RS #B) are QCLed, it means that the UE is allowed to apply some or all of the large-scale channel parameters estimated at the antenna port A to the channel measurement from the antenna port B. QCL may need to relate different parameters depending on the situation, such as 1) time tracking affected by average delay and delay spread, 2) frequency tracking affected by Doppler shift and Doppler spread, 3) radio resource management (RRM) affected by average gain, and 4) beam management (BM) affected by spatial parameters. Accordingly, the 5G system supports four types of QCL relationships as shown in Table 8 below.

[0189] QCL typeLarge-scale characteristicsADoppler shift, Doppler spread, average delay, delay spreadBDoppler shift, Doppler spreadCDoppler shift, average delayDSpatial Rx parameter

[0190] The above spatial RX parameter may collectively refer to some or all of various parameters, such as Angle of arrival (AoA), Power Angular Spectrum (PAS) of AoA, Angle of departure (AoD), PAS of AoD, transmit / receive channel correlation, transmit / receive beamforming, and spatial channel correlation.

[0191] The above QCL relationship can be set to the terminal through the RRC parameters TCI-State and QCL-Info as shown in Table 9 below. Referring to Table 9, the base station can set one or more TCI states to the terminal and inform the RS referencing the ID of the TCI state, i.e., up to two QCL relationships (qcl-Type1, qcl-Type2) for the target RS. At this time, each QCL information (QCL-Info) included in the above TCI state includes the serving cell index and BWP index of the reference RS indicated by the corresponding QCL information, the type and ID of the reference RS, and the QCL type as shown in Table 8 above.

[0192] TCI-State ::= SEQUENCE {tci-StateId TCI-StateId,(ID of the corresponding TCI state)qcl-Type1 QCL-Info,(QCL information of the first reference RS of the RS (target RS) referencing the corresponding TCI state ID)qcl-Type2 QCL-Info OPTIONAL, -- Need R(QCL information of the second reference RS of the RS (target RS) referencing the corresponding TCI state ID)...}QCL-Info ::= SEQUENCE {cell ServCellIndex OPTIONAL, -- Need R(serving cell index of the reference RS indicated by the corresponding QCL information)bwp-Id BWP-Id OPTIONAL, -- Cond CSI-RS-Indicated(BWP index of the reference RS indicated by the corresponding QCL information)referenceSignal CHOICE {csi-rs NZP-CSI-RS-ResourceId,ssb SSB-Index(either the CSI-RS ID or SSB ID indicated by the corresponding QCL information) one)},qcl-Type ENUMERATED {typeA, typeB, typeC, typeD},...}

[0193] Fig. 5 is a diagram illustrating an example of base station beam allocation according to TCI state settings.

[0194] Referring to FIG. 5, the base station can transmit information about N different beams to the terminal through N different TCI states. For example, when N = 3 as shown in FIG. 5, the base station can notify that the antenna ports referencing the different TCI states 500, 505, or 510 have different spatial Rx parameters, i.e., are associated with different beams, by setting the qcl-Type2 parameter included in the three TCI states (500, 505, 510) to be associated with the CSI-RS or SSB corresponding to the different beams and to QCL type D.

[0195] For PDCCH DMRS (demodulation reference signal), the TCI state combinations applicable to the PDCCH DMRS antenna port are as shown in Table 10 below. In Table 10, 'Valid TCI state Configuration' = 4 is a combination that the terminal assumes before RRC configuration, and cannot be configured after RRC configuration.

[0196] Valid TCIstate ConfigurationDL RS 1qcl-Type1DL RS 2(if configured)qcl-Type2(if configured)1TRSQCL-TypeATRSQCL-TypeD2TRSQCL-TypeACSI-RS (BM)QCL-TypeD3CSI-RS (CSI)QCL-TypeA 4SS / PBCH BlockQCL-TypeASS / PBCH BlockQCL-TypeD

[0197] In 5G systems, a hierarchical signaling method, as illustrated in FIG. 6, is supported for dynamic allocation of PDCCH beams. FIG. 6 is a diagram illustrating an example of an allocation method for PDCCH beams.

[0198] Referring to FIG. 6, the base station can set N TCI states (605, 610, ..., 620) to the terminal through RRC signaling (600), and can set some of them as TCI states for CORESET (625). Thereafter, the base station can indicate one of the TCI states (630, 635, 640) for CORESET to the terminal through MAC CE signaling (645). Thereafter, the terminal receives the PDCCH based on the beam information included in the TCI state indicated by the MAC CE signaling.

[0199] FIG. 7 is a diagram illustrating an example of a TCI indication MAC CE signaling structure for the PDCCH DMRS.

[0200] Referring to FIG. 7, the TCI indication MAC CE signaling for the PDCCH DMRS consists of 2 bytes (16 bits) and includes 1 bit of reserved bit (710), 5 bits of serving cell ID (715), 2 bits of BWP ID (720), 2 bits of CORESET ID (725), and 6 bits of TCI state ID (730).

[0201] Figure 8 is a diagram illustrating an example of CORESET and search space beam settings.

[0202] Referring to FIG. 8, the base station can indicate one of the TCI state lists included in the CORESET (800) configuration via MAC CE signaling (805). Until another TCI state is indicated to the corresponding CORESET via another MAC CE signaling, the terminal considers that the same QCL information (beam #1, 805) is applied to one or more search spaces (810, 815, 820) connected to the CORESET.

[0203] The above-described PDCCH beam allocation method has a problem in that it is difficult to instruct a beam change faster than the MAC CE signaling delay, and also has a disadvantage in that the same beam is applied to all CORESETs regardless of the search space characteristics, which makes flexible PDCCH beam operation difficult. In the embodiments of the present disclosure below, more flexible PDCCH beam setting and operation methods are provided, including 'PDCCH QCL Determination Method 1', 'PDCCH QCL Determination Method 2', and 'PDCCH QCL Determination Method 3'. In describing the embodiments of the present disclosure below, several distinct examples are provided for the convenience of explanation, but these are not mutually exclusive and can be applied in appropriate combination depending on the situation.

[0204] PDCCH QCL Determination Method 1

[0205] A base station can set one or more TCI states for a specific control resource set to a terminal, and can activate one of the set TCI states through a MAC CE activation command. For example, if {TCI state#0, TCI state#1, TCI state#2} are set as TCI states for control resource set #1, the base station can transmit a command to the terminal to activate TCI state#0 for control resource set #1 through MAC CE. Based on the activation command for the TCI state received through MAC CE, the terminal can correctly receive DMRS of the corresponding control resource set based on QCL information in the activated TCI state.

[0206] PDCCH QCL Determination Method 2

[0207] For a control resource set (control resource set #0) with an index set to 0, if the terminal has not received a MAC CE activation command for the TCI state of control resource set #0, the terminal can assume that the DMRS transmitted in control resource set #0 has been QCLed with the SSB identified during the initial access process of the terminal or during a non-contention-based random access process that is not triggered by a PDCCH command.

[0208] PDCCH QCL Determination Method 3

[0209] For a control resource set (control resource set #X) whose index is set to a value other than 0, if the terminal has not set a TCI state for the control resource set #X, or has set one or more TCI states but has not received a MAC CE activation command to activate one of them, the terminal may assume that the DMRS transmitted in the control resource set #X is QCL with the SSB identified during the initial connection process of the terminal.

[0210] Below, we describe methods for saving energy at base stations. To support ultra-high-speed data services, spatial multiplexing using multiple transmit / receive antennas can increase data rates. Generally, the number of required power amplifiers (PAs) increases proportionally to the number of transmit antennas installed at a base station or terminal. The maximum output power of a base station and terminal depends on the characteristics of the PA, and the maximum output power of a base station generally varies depending on the cell size covered by the base station. The maximum output power is typically expressed in dBm. The maximum output power of a terminal is typically 23 dBm or 26 dBm.

[0211] For example, a commercial 5G base station might feature 64 transmit antennas and corresponding 64 power amplifiers operating in the 3.5 GHz frequency band, operating at a bandwidth of 100 MHz. Ultimately, the energy consumption of the base station increases in proportion to the power amplifier output and operating time. Compared to LTE base stations, 5G base stations have a relatively high operating frequency band, allowing them to utilize a wider bandwidth and have a larger number of transmit antennas. While this characteristic allows for higher data rates, it comes at the cost of increased base station energy consumption. Therefore, the more base stations there are in a mobile communications network, the greater the energy consumption of the entire mobile communications network.

[0212] As mentioned above, the energy consumption of a base station is largely determined by the operation of the power amplifier. Since the power amplifier is involved in the base station's transmission operations, the base station's downlink transmission operations are closely related to its energy consumption. Comparatively, the base station's uplink reception operations account for a relatively small portion of its energy consumption. The physical channels and physical signals transmitted by the base station in the downlink are as follows.

[0213] - PDSCH: Downlink data channel containing data to be transmitted to one or more terminals.

[0214] - PDCCH: A downlink control channel containing scheduling information for PDSCH and PUSCH. Alternatively, the base station can transmit control information such as slot format and power control commands through this channel alone, without the PDSCH or PUSCH to be scheduled. Scheduling information includes resource information to which the PDSCH or PUSCH is mapped, HARQ-related information, power control information, etc.

[0215] - PBCH: A downlink broadcast channel that provides MIB, which is essential system information required for transmission and reception of data channels and control channels of the terminal.

[0216] - PSS: A signal that serves as a reference for DL ​​time / frequency synchronization and provides some cell ID information.

[0217] - SSS(: A signal that serves as a reference for DL ​​time and / or frequency (hereinafter referred to as time / frequency) synchronization and provides some remaining information such as cell ID.

[0218] - DM-RS: Reference signal for terminal channel estimation for each of PDSCH, PDCCH, and PBCH

[0219] - CSI-RS (: Downlink signal that serves as a standard for measuring the downlink channel status of the terminal

[0220] - PT-RS (phase-tracking reference signal): Downlink signal for phase tracking

[0221] From a base station energy conservation perspective, suspending downlink transmission at the base station can significantly reduce base station energy consumption due to the resulting power amplifier shutdown. Furthermore, the reduced operation of other base station components, including the baseband, in addition to the power amplifier can also lead to additional energy savings. Similarly, even though uplink reception accounts for a relatively small portion of the base station's overall energy consumption, the ability of the base station to suspend uplink reception can result in additional energy savings.

[0222] The downlink transmission behavior of a base station is fundamentally determined by the amount of downlink traffic. For example, if there is no data to transmit to a terminal via the downlink, the base station does not need to transmit the PDSCH and the PDCCH for scheduling the PDSCH. Alternatively, if transmission can be temporarily delayed for reasons such as the data being insensitive to transmission delay, the base station may not transmit the PDSCH and / or PDCCH. For convenience of explanation below, this method of reducing base station energy consumption by not transmitting or appropriately controlling PDSCH and / or PDCCH transmission associated with data traffic is referred to as "Base Station Energy Saving Method 1-1."

[0223] In contrast, physical channels and physical signals such as PSS, SSS, PBCH, and CSI-RS have the characteristic of being repeatedly transmitted at a predetermined, promised cycle regardless of data transmission to the terminal. Therefore, even if the terminal does not receive data, it can continuously update downlink time / frequency synchronization, downlink channel status, radio link quality, etc. In other words, PSS, SSS, PBCH, and CSI-RS necessarily require downlink transmission regardless of downlink data traffic, and thus induce base station energy consumption. Therefore, base station energy can be saved by controlling the transmission of signals unrelated to (or with low relevance to) data traffic to occur less frequently (hereinafter referred to as 'base station energy saving method 1-2').

[0224] By using 'Base Station Energy Saving Method 1-1' or 'Base Station Energy Saving Method 1-2', the energy saving effect of the base station can be maximized by stopping or minimizing the operation of the base station's power amplifier and related RF devices, baseband devices, etc. during the time period when the base station does not perform downlink transmission.

[0225] Alternatively, the energy consumption of the base station can be reduced by switching off some of the base station antennas or power amplifiers (hereinafter referred to as 'Base Station Energy Saving Method 2'). In this case, the energy saving effect of the base station may be counterproductive, such as a decrease in cell coverage or a decrease in throughput. For example, there may be a base station equipped with 64 transmit antennas and corresponding 64 power amplifiers in the 3.5 GHz frequency band described above and operating in a 100 MHz bandwidth. In order to save energy at such a base station, if only 4 transmit antennas and 4 power amplifiers are activated for a certain period of time and the rest are switched off, the base station energy consumption during that period is reduced to approximately 1 / 16 (= 4 / 64). When only four transmit antennas and four power amplifiers are activated for a given time period and the rest are switched off, it becomes difficult to achieve the cell coverage and throughput assuming the existing 64 antennas and power amplifiers due to the decrease in maximum transmit power and the decrease in beamforming gain.

[0226] In the following description, the base station mode that applies an operation for saving base station energy is called the base station energy saving mode (ES mode) to distinguish it from the general base station operation, and the base station mode that applies the general base station operation is called the base station normal mode.

[0227] Another way to support ultra-high-speed data services is for 5G systems to support ultra-wide bandwidth signal transmission and reception, ranging from tens to hundreds of megahertz (MHz) or even several gigahertz (GHz). Ultra-wide bandwidth signal transmission and reception can be supported through a single component carrier (CC) or through carrier aggregation (CA) technology that combines multiple component carriers. When a mobile carrier cannot secure a single component carrier with sufficient bandwidth to provide ultra-high-speed data services, CA technology combines individual component carriers with relatively small bandwidths. This increases the total bandwidth available and ultimately enables ultra-high-speed data services.

[0228] In general, the lower the frequency band, the greater the coverage due to relatively low path loss, and the larger the frequency band, the less the coverage due to relatively high path loss. In low frequency bands, the frequencies that can be used for mobile communication are relatively small and the bandwidth is small, whereas in high frequency bands, it is relatively easy to secure wide bandwidth, making them suitable for ultra-high-speed data services. As mobile communication systems evolve, efforts are being made to discover and utilize new frequency bands. For example, although it is still in the early discussion stage, the next-generation mobile communication system, 6G (6 th In mobile communication systems, THz (Terahertz, 10 12 Hz) band is being considered as one of the candidate frequencies.

[0229] Typically, mobile carriers secure multiple frequency bands to provide mobile communication services to users. For example, a mobile carrier can combine existing LTE frequency bands with newly acquired 5G frequency bands to operate a combined LTE and 5G system. Another example is that a mobile carrier can secure 5G frequency bands across multiple bands and then combine these bands to provide mobile communication services through 5G carrier aggregation (CA). As mentioned above, because characteristics such as coverage and bandwidth vary depending on the frequency band, services that combine multiple frequency bands are increasingly popular, rather than those that rely on a single frequency band.

[0230] Figure 9 is a diagram illustrating an example of configuring a 5G system by combining three constituent carriers for each of uplink and downlink.

[0231] According to FIG. 9, in the carrier aggregation system, each component carrier is divided into a PCell or a SCell and operated. The PCell (primary cell, or first cell) provides basic radio resources to the terminal and refers to a cell that serves as a reference for performing operations such as initial access and handover of the terminal. The PCell is composed of a downlink primary frequency (or primary component carrier, PCC) and an uplink primary frequency. The terminal can transmit UCI, which is uplink control information including HARQ ACK / NACK for feedback on whether data received from the base station has an error or not, or CSI indicating the channel status between the base station and the terminal, through the uplink control channel PUCCH. The PUCCH can be transmitted through the PCell. The SCell (secondary cell, or second cell) is a cell that provides additional radio resources to the terminal along with the PCell, and is composed of a downlink secondary frequency (or secondary component carrier, SCC) and an uplink secondary frequency, or a downlink secondary frequency.

[0232] The configuration of each component carrier is independent of each other, and downlink carrier aggregation and uplink carrier aggregation can be applied independently of each other. For example, a carrier aggregation that combines two component carriers, one with a 100MHz bandwidth and one with a 50MHz bandwidth, can be applied to the downlink, and only one component carrier with a 100MHz bandwidth can be used for the uplink (i.e., carrier aggregation may not be applied). In the present invention, unless otherwise specified, cells and component carriers are used interchangeably and indiscriminately. The base station can inform the terminal of the carrier aggregation-related settings, such as which component carriers to combine, how many component carriers to combine, and bandwidth-related control information of each component carrier, through signaling.

[0233] In a system applying carrier aggregation (CA) technology that combines multiple component carriers as described above, the transmission of SSB on a given component carrier can be simplified to reduce the energy consumption of the base station. That is, by having the base station omit SSB transmission or make SSB transmission frequency rare, the base station energy used for SSB transmission can be reduced. However, in this case, a method is needed to replace or supplement the functions that the base station originally provided to the terminal through SSB transmission, such as time-frequency synchronization, QCL or beam management (BM), and uplink transmission power reference signal.

[0234] The following describes a method for reducing base station energy consumption by simplifying SSB transmission proposed in the present disclosure through specific examples. While the present disclosure describes the examples through multiple examples, they are not independent and one or more examples may be applied simultaneously or in combination.

[0235] <Example 1>

[0236] A first embodiment describes a method for a terminal to determine the QCL of a cell when a base station simplifies SSB transmission in a given cell to reduce base station energy consumption.

[0237] Specifically, the first embodiment relates to a method for a terminal to determine the QCL of a PDCCH when simplifying SSB transmission of an SCell to reduce base station energy consumption in a system applying carrier aggregation. To simplify SSB transmission to reduce base station energy used for SSB transmission, the base station may omit SSB transmission of the SCell or make the SSB transmission frequency rare. For the convenience of the following description, such an SCell is referred to as an 'SSB-less SCell'.

[0238] According to the QCL determination method of the above-described PDCCH (or PDCCH DMRS) ('PDCCH QCL determination method 2', 'PDCCH QCL determination method 3'), if the terminal does not receive a MAC CE activation command for the TCI state of the SCell from the base station, the terminal determines that the PDCCH DMRS of the corresponding SCell has QCL with the SSB identified during the initial access process of the terminal or the non-contention-based random access process that is not triggered by the PDCCH command. However, in the case of the first embodiment, due to the simplified SSB transmission operation, the SSB that serves as the basis for the QCL reference for the PDCCH DMRS of the 'SSB-less SCell' may not exist, or even if it exists, its accuracy may not be guaranteed.

[0239] To solve this problem, the base station can designate a 'reference cell', which is a reference for the QCL reference for the PDCCH DMRS, in addition to an SCell with simplified SSB transmission ('SSB-less SCell'), and signal it to the UE. Additionally, the base station can designate an RS that the UE should reference in the 'reference cell' and signal it to the UE. The RS can be an SSB or CSI-RS. The 'reference cell' can be a PCell or a second SCell, excluding the 'SSB-less SCell', among the cells constituting the carrier bundle. For example, the signaling can be upper layer signaling, and an SSB index or a CSI-RS resource index can be indicated to indicate the RS.

[0240] FIG. 10 is a diagram illustrating an example of a method for determining QCL of a terminal when the terminal does not receive a MAC CE activation command for the TCI state of an SCell from a base station according to the first embodiment. Although not illustrated, if the terminal receives a MAC CE activation command for the TCI state of an SCell from the base station, the terminal can determine the QCL of the PDCCH DMRS according to the 'PDCCH QCL Determination Method 1' described above.

[0241] In step 1010, the terminal determines whether the PDCCH it wants to receive is transmitted from the 'SSB-less SCell'. If the PDCCH is transmitted from the 'SSB-less SCell', in step 1030, the terminal determines that the RS of the 'reference cell' that the base station notified the terminal through signaling is QCL with the corresponding PDCCH DMRS. The RS of the 'reference cell' can be an SSB or CSI-RS, and the base station can notify the terminal through signaling. The terminal can receive the PDCCH based on the determined QCL relationship.

[0242] If the SCell on which the PDCCH that the terminal wants to receive is transmitted is not an 'SSB-less SCell', then in step 1020, the terminal determines that the PDCCH DMRS of the corresponding SCell is QCL with the SSB identified during the terminal's initial access process or the non-contention-based random access process that is not triggered by a PDCCH command. This is the same as the 'PDCCH QCL determination method 2' or 'PDCCH QCL determination method 3' above. The terminal can receive the PDCCH based on the determined QCL relationship.

[0243] The above flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0244] In the case of PDSCH transmitted from a base station to a terminal in SCell, the terminal can correctly receive the PDSCH based on the QCL information in the TCI state for PDSCH activated by the MAC CE activation command for PDSCH QCL. If the terminal does not receive the MAC CE activation command for PDSCH QCL or the MAC CE activation command is invalid, the terminal can determine that the QCL of the PDSCH is the same as the QCL of the PDCCH. Therefore, if the PDCCH QCL determination method of the terminal in step 1030 is combined, in this case, the terminal determines that the PDSCH DMRS is QCL with the PDCCH DMRS, and then determines that the PDCCH DMRS is QCL with the RS of the 'reference cell', and as a result, the terminal can determine that the PDSCH DMRS is QCL with the RS of the 'reference cell'. At this time, the terminal can receive the PDSCH according to the determined QCL relationship.

[0245] <Example 2>

[0246] A second embodiment describes a method for signaling to a terminal when a base station simplifies SSB transmission in a given cell to reduce base station energy consumption.

[0247] Specifically, the second embodiment describes a method for a base station to inform a terminal that SSB transmission of an SCell ('SSB-less SCell') has been simplified in order to reduce base station energy consumption in a system applying carrier aggregation.

[0248] SSB configuration information related to SSB transmitted from a given cell may include the following. The base station may inform the terminal of the SSB configuration information through upper layer signaling.

[0249] - absoluteFrequencySSB: Information indicating the frequency domain mapping location of SSB

[0250] - ssb-PositionsInBurst: Information indicating the time-domain mapping positions of SSB. For example, among the time-domain mapping positions of SSB agreed upon in advance, whether an SSB is actually mapped can be expressed in bitmap format. For example, by linking an 8-bit bitmap consisting of b1 to b8 and 8 pre-agreed time-domain positions of SSB (b1: SSB1, b2: SSB2, ..., b8: SSB8), if the bit is '1', it can be indicated that an SSB is actually transmitted at the time-domain position, and if the bit is '0', it can be indicated that an SSB is not actually transmitted at the time-domain position.

[0251] - ssb-periodicityServingCell: Information indicating the SSB transmission period. It can be expressed in ms, and can be set to values ​​such as 5ms, 10ms, 20ms, 40ms, 80ms, and 160ms.

[0252] - ss-PBCH-BlockPower: Information indicating EPRE (energy per resource element), which represents the transmission power of the SSS (Secondary Synchronization Signal) that constitutes SSB. It is expressed in dBm. For example, it can be set to a value within the range of -60dBm to 50dBm. The same value as SSS EPRE is usually applied to PSS EPRE, PBCH EPRE, and PBCH DMRS EPRE.

[0253] When the base station omits SSB transmission for 'SSB-less SCell' operation, the base station can notify the terminal that the SSB transmission is omitted by not signaling at least one of the SSB configuration information to the terminal. Accordingly, if the terminal does not receive signaling of the SSB configuration information (or at least one of the information included in the SSB configuration information) from the base station, the terminal can determine that the SSB transmission is omitted. Alternatively, the base station can configure a special state indicating that the SSB transmission is omitted with the SSB configuration information and notify the terminal of this. For example, the SSB transmission can be indicated by setting all bits of the bitmap indicating the ssb-PositionsInBurst to '0'. Alternatively, a special state indicating that the SSB transmission is omitted can be added to the ssb-periodicityServingCell or ss-PBCH-BlockPower. That is, for example, when SSB transmission is omitted, the base station can set at least one piece of information included in the SSB configuration information to a predetermined value, and when the terminal receives the SSB configuration information as described above, it can confirm that SSB transmission is omitted.

[0254] If the base station uses infrequent SSB transmission frequency for 'SSB-less SCell' operation, a status indicating the corresponding value can be added to the above SSB configuration information. For example, values ​​such as 320ms or 540ms, which are relatively larger than the existing values, can be added as an additional status for ssb-periodicityServingCell.

[0255] Alternatively, in addition to the SSB configuration information described above, a separate additional signaling may be defined as a method for the base station to notify the terminal of the 'SSB-less SCell' operation. Accordingly, when the terminal receives the signaling from the base station, it may recognize that SSB transmission has been omitted in the cell corresponding to the signaling or that the cell operates as an 'SSB-less SCell' with a rare SSB transmission frequency.

[0256] The operation of the second embodiment will be described below with reference to Fig. 11. Fig. 11 is a drawing illustrating an example of the operation according to the second embodiment.

[0257] Referring to FIG. 11, in step 1110, a base station (1102) may transmit a UE capability information request message to a terminal (1101). In response to the base station's request for UE capability information, the terminal transmits UE capability information to the base station in step 1120. The UE capability information may include at least one of control information indicating whether the terminal supports carrier aggregation, bandwidth-related control information of each component carrier when supporting carrier aggregation, whether the terminal supports base station energy saving operation, and whether the terminal supports base station SSB transmission simplification operation.

[0258] At step 1130, the terminal can perform a measurement report for neighboring cells. For example, if the strength of a received signal (for example, the received signal may be a reference signal) from neighboring cells observed by the terminal is greater than a predetermined threshold, the terminal can include the ID of the corresponding cell and the strength of the received signal in a measurement report and transmit it to the base station. The reference signal observed by the terminal for the measurement report may be an SSB or CSI-RS transmitted by the neighboring cell. The base station can inform the terminal of control information for the measurement report through signaling. The control information for the measurement report of the terminal may include at least a part of the control information related to the following. The signaling may be upper layer signaling.

[0259] - Information about the reference signal of the surrounding cell being measured. For example, whether it is SSB or CSI-RS.

[0260] - Subcarrier spacing of the above reference signal

[0261] - Time / frequency domain location of the above reference signal

[0262] - Size of the start / frequency domain of the above reference signal

[0263] - When reporting measurement results measured by the terminal to the base station, whether to report periodically or based on a specific event

[0264] The base station can determine whether to configure a carrier bundle for the terminal or instruct a handover to another cell by referring to the terminal's measurement report, UE capability information, etc. Determining whether to configure a carrier bundle may mean, for example, determining whether to combine an additional carrier (SCell) with the current terminal's PCell.

[0265] If the base station decides to apply carrier aggregation operation and SSB-less SCell operation to the terminal, the base station may transmit to the terminal, in step 1140, relevant information required for SCell aggregation of the terminal, in an 'RRC reconfiguration' message. This is called the 'SCell addition' step. The relevant information required for carrier aggregation may include information on the carrier bandwidth and center frequency of the SCell, common control information for the physical channel of the SCell, control information indicating that the SCell is an 'SSB-less SCell' that simplifies SSB transmission, etc. The control information indicating that the SCell is an 'SSB-less SCell' that simplifies SSB transmission may follow the contents described above.

[0266] The terminal completes the process for performing communication with the SCell according to the received 'RRC reconfiguration' message, and then notifies the base station of the completion of the 'SCell addition' setup procedure by transmitting an 'RRC reconfiguration complete' message to the base station at step 1150.

[0267] In step 1160, the base station can instruct the terminal that completed the SCell configuration through the SCell addition to activate the SCell. When the SCell activation is performed, the terminal can monitor the PDCCH for scheduling the downlink data and uplink data of the corresponding SCell, and can perform operations such as receiving the PDSCH scheduled by the PDCCH, transmitting the PUSCH scheduled by the PDCCH, transmitting the SRS in the SCell uplink, reporting CSI, and transmitting the PUCCH. The base station can notify the terminal of the SCell activation instruction (or command) through MAC signaling or physical layer signaling. Instead of the RRC reconfiguration message of step 1140, the base station can include control information indicating that the SCell is an 'SSB-less SCell' that simplifies SSB transmission in the SCell activation command of step 1160 and notify the terminal of this. The control information indicating that the SCell included in the above SCell activation command is an 'SSB-less SCell' that simplifies SSB transmission may be, for example, a bit indicating that each cell added to the SCell Activation / Deactivation MAC CE is an 'SSB-less SCell', or may correspond to a separate MAC CE indicating that each cell is an 'SSB-less SCell'.

[0268] After step 1160, the terminal is ready to transmit and receive data with both the PCell and SCell of the base station.

[0269] The above flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0270] A terminal that has been notified by the base station that the SCell is an 'SSB-less SCell' can perform QCL determination according to the first embodiment described above.

[0271] Also, since there may not be enough SSB for the SCell, and thus measurement reporting based on SSB may no longer be valid, similar to the first embodiment, the base station may support the measurement reporting operation of the terminal by notifying the terminal of a separate 'reference cell' and / or 'reference signal' for measurement reporting of the SCell. For example, the base station may indicate to the terminal a separate reference cell for measurement reporting (or a reference cell and a specific reference signal on the reference cell), or may instruct the terminal to perform measurement reporting based on another reference signal (e.g., CSI-RS) on the SCell.

[0272] In addition, the terminal generally determines the transmission power of an uplink signal (e.g., SRS) or an uplink channel (PUCCH or PUSCH) in a given cell by referring to the reception strength of the SSB of the corresponding cell to determine the degree of path loss between the terminal and the base station and reflecting this in the uplink transmission power control. However, in the case of 'SSB-less SCell', as described above, since the corresponding SSB may not exist, the base station may designate a 'reference cell' or / and a 'reference signal' that serves as a standard for the uplink transmission power of the terminal and inform the terminal of this. For example, the reference cell or / and reference signal for determining the path loss may be the reference cell or / and reference signal for QCL determination indicated in the first embodiment, or it is also possible for the reference cell or / and reference signal for determining the path loss to be indicated to the terminal separately from the reference cell or / and reference signal for QCL determination. The reference signal may be, for example, an SSB or a CSI-RS.

[0273] <Example 3>

[0274] A third embodiment describes a method of interpreting the above-described SSB configuration information when a base station omits SSB transmission in a given cell to reduce base station energy consumption.

[0275] Specifically, the third embodiment describes a method of interpreting existing ss-PBCH-BlockPower control information when SSB transmission of SCell is omitted to reduce base station energy consumption in a system applying carrier bundles.

[0276] First, a method for setting the transmission power of a downlink signal in a base station normal mode to which base station energy consumption saving operation is not applied is described.

[0277] The transmission power of a signal can be expressed as power spectral density (PSD) linked to the bandwidth. The unit of PSD is usually expressed in Watt / Hz, and it means power per unit bandwidth. The transmission bandwidth refers to the bandwidth occupied by the signal transmitted by the base station, and can be expressed in units of MHz. A concept similar to PSD can be used as EPRE. EPRE means energy per RE. EPRE can be expressed in units of dBm.

[0278] Fig. 12 is a diagram showing an example of EPRE settings of downlink signals in a 5G system. Basically, the base station sets the EPRE (1210) of the SSS, adjusts the CSI-RS EPRE (1220) based on the SSS EPRE, and adjusts the PDSCH EPRE (1230) compared to the CSI-RS EPRE, the PDSCH DMRS EPRE compared to the PDSCH EPRE, etc. In other words, the EPRE relationships of the downlink signals are interconnected. The base station can inform the terminal of the EPRE of the downlink signal through the following method. The signaling by which the base station informs the terminal of the power-related information described above can be upper layer signaling or DCI.

[0279] - "ss-PBCH-BlockPower" (1215): This parameter controls the EPRE (1210) of SSS, which the base station notifies the terminal through signaling. It is expressed in dBm. PSS EPRE, PBCH EPRE, and PBCH DMRS EPRE are usually applied with the same value as SSS EPRE.

[0280] - "powerControlOffsetSS" (1225): This parameter controls the power offset of CSI-RS compared to SSS RE, and is notified by the base station to the terminal through signaling. This is expressed in dB as the ratio of CSI-RS EPRE to SSS EPRE. As a result, CSI-RS EPRE (1220) = "ss-PBCH-BlockPower" + "powerControlOffsetSS".

[0281] - "powerControlOffset" (1235): This parameter controls the power offset of PDSCH RE compared to CSI-RS RE, and the base station notifies the terminal through signaling. This is expressed in dB as the ratio of PDSCH EPRE to CSI-RS EPRE. As a result, PDSCH EPRE (1230) = "ss-PBCH-BlockPower" + "powerControlOffsetSS" + "powerControlOffset".

[0282] - Ratio of PDSCH EPRE to PDSCH DMRS EPRE: The ratio of PDSCH EPRE to PDSCH DMRS EPRE is determined according to the PDSCH DMRS settings separately determined by the base station.

[0283] If the base station omits SSB transmission of the SCell to save energy, the above "ss-PBCH-BlockPower" indicating the transmission power of the SSS constituting the SSB is no longer related to the SSB transmission of the SCell. However, "ss-PBCH-BlockPower" can still be used as a reference for calculating the transmission power of the CSI-RS and PDSCH of the SCell.

[0284] Therefore, the operation of the terminal for the "ss-PBCH-BlockPower" of the SCell can be divided into the following operations depending on whether the SCell skips SSB transmission or not.

[0285] - When SCell's "ss-PBCH-BlockPower" is signaled and SCell SSB transmission is not omitted: The UE recognizes that SCell's SSB transmission has actually occurred, and calculates the transmission power of SSS from "ss-PBCH-BlockPower". In addition, the transmission power of SCell CSI-RS and SCell PDSCH is calculated based on the above "ss-PBCH-BlockPower".

[0286] - When SCell's "ss-PBCH-BlockPower" is signaled and SCell SSB transmission is omitted: The UE recognizes that SCell's SSB transmission did not actually occur and does not calculate the transmission power of SSS. In addition, the transmission power of SCell CSI-RS and SCell PDSCH is calculated based on the above "ss-PBCH-BlockPower".

[0287] - If SCell SSB transmission is omitted without signaling "ss-PBCH-BlockPower" of SCell: The terminal recognizes that the SSB transmission of SCell did not actually occur and does not calculate the transmission power of SSS. The base station can inform the terminal of a cell other than the SCell as a 'reference cell', and the terminal calculates the CSI-RS transmission power of the SCell and the PDSCH transmission power of the SCell based on the SSS transmission power of the 'reference cell'.

[0288] <Example 4>

[0289] The fourth embodiment defines a maximum receive timing difference (MRTD) between downlink signals received by a terminal from cell A and cell B constituting a carrier bundle, respectively, when simplifying SSB transmission of SCell to reduce base station energy consumption in a system applying carrier bundles.

[0290] Table 11 shows the tolerance criteria for the above MRTD in a typical carrier bundle environment. Table 11 defines the tolerance criteria for MRTD according to the detailed conditions of the frequency band to which the carrier bundle is applied, as follows.

[0291] - FR1 (Frequency range 1): A frequency within the range of 410 to 7125 MHz, which is a relatively low frequency band compared to FR2.

[0292] - FR2 (Frequency range 2): A frequency within the range of 24.25 to 52.6 GHz, which is a relatively high frequency band compared to FR1.

[0293] - Between FR1 and FR2: This is when the frequencies within FR1 and within FR2 are configured as a carrier bundle system.

[0294] - Intra-band non-contiguous CA: This refers to carrier bundles between cells operating at non-contiguous frequencies within the same frequency band. Compared to inter-band CA, this type of CA has relatively small channel environment differences between cells, and thus has a relatively small MRTD tolerance.

[0295] Inter-band CA: Carrier aggregation between cells operating in different frequency bands. Compared to intra-band non-contiguous CA, this reflects the relatively large channel environment differences between cells, and thus applies a relatively large MRTD tolerance.

[0296] Frequency RangeIntra-band non-contiguous CAInter-band CAFR13 μs33 μsFR20.26 μs8 μsBetween FR1 and FR2-25 μs

[0297] As described above, when simplifying the SSB transmission of the SCell to reduce base station energy consumption, the terminal needs to refer to the indicated 'reference cell' for the purpose of determining the QCL of the SCell or reporting measurements for the SCell. Since the 'reference cell' must have a similarity to the QCL or channel state of the SCell, it is desirable to apply a relatively small value to the tolerance criterion of MRTD. Therefore, according to the fourth embodiment, in the case of a carrier aggregation system including an 'SSB-less SCell', the MRTD tolerance criterion can be defined as shown in Table 12 below. According to Table 12, the tolerance criterion of MRTD is defined according to the detailed conditions of the frequency band to which the carrier aggregation is applied.

[0298] - FR1: MRTD (A3) of a carrier bundle system including 'SSB-less SCell' satisfies the relationship A1 ≤ A3 < A2.

[0299] - FR2: MRTD (B3) of a carrier bundle system including 'SSB-less SCell' satisfies the relationship B1 ≤ B3 < B2.

[0300] - Between FR1 and FR2: The MRTD (C3) of the carrier bundle system including 'SSB-less SCell' satisfies the relationship C3 < C2.

[0301] That is, for CA including SSB-less SCell, the allowable MRTD value can be less than or equal to that for inter-band CA and greater than that for intra-band CA.

[0302] Frequency RangeIntra-band non-contiguous CAInter-band CACA with SSB-less SCellFR13 μs (A1)33 μs (A2)A3FR20.26 μs (B1)8 μs (B2)B3Between FR1 and FR2-25 μs (C2)C3

[0303] Therefore, for a carrier aggregation system including 'SSB-less SCell', the maximum reception timing difference (MRTD) between downlink signals received from different cells A and B of the terminal must satisfy the allowable criteria of Table 12 above. The base station must not set a CA setting that does not satisfy the MRTD setting, and the terminal may determine that the CA setting from the base station is an incorrect base station setting and may not follow the setting if the CA setting from the base station does not satisfy the MRTD setting.

[0304] <Example 5>

[0305] The fifth embodiment describes examples of terminal procedures and base station procedures according to a preferred embodiment of the present disclosure. The terminal procedures and base station procedures of the fifth embodiment can be performed in combination with at least one of the first through fourth embodiments.

[0306] FIG. 13 is a diagram illustrating an example of a terminal procedure according to one embodiment of the present disclosure. Specifically, FIG. 13 is a flowchart illustrating a procedure in which a terminal performs the corresponding operation according to base station settings when a base station simplifies SSB transmission of SCell to reduce energy consumption in a system applying carrier aggregation.

[0307] Referring to FIG. 13, in step 1301, the terminal reports UE capability information including the capability to support the base station power saving mode to the base station. The UE capability information may specifically include at least one piece of information related to the base station power saving mode, such as information indicating whether the terminal supports the base station power saving mode, information indicating whether the terminal supports carrier aggregation, information indicating whether the terminal supports the SSB transmission simplification operation of the base station, control information related to the frequency band supported by the terminal, and control information related to the channel bandwidth supported by the terminal.

[0308] At step 1302, the terminal may be notified of an 'SSB-less SCell' configuration from the base station. The 'SSB-less SCell' configuration may include control information indicating that the SCell is an 'SSB-less SCell' that simplifies SSB transmission, information according to the above-described embodiments, etc., and the specific method follows the above-described embodiments.

[0309] In step 1303, the terminal performs an 'SSB-less SCell' operation according to the base station settings. According to the above-described embodiment, the terminal can determine the QCL of the 'SSB-less SCell' with reference to the 'reference signal' of the 'reference cell', and / or perform at least one of generating and transmitting a measurement report, determining an uplink signal or channel transmission power, and setting a downlink signal transmission power based on the reference cell and / or the reference signal set according to the above-described embodiment. In addition, the terminal must satisfy the MRTD tolerance according to the above-described embodiment.

[0310] The steps described in FIG. 13 may be omitted, the order changed, or steps not described may be added to implement the present disclosure. The above-described flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, the various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0311] FIG. 14 is a diagram illustrating an example of a base station procedure according to one embodiment of the present disclosure. Specifically, FIG. 14 is a flowchart illustrating a procedure for notifying a terminal of the relevant settings and performing related operations when a base station simplifies SSB transmission of an SCell to reduce energy consumption in a system applying carrier aggregation.

[0312] Referring to FIG. 14, in step 1401, the base station may request the terminal to transmit UE capability information. In step 1402, the base station obtains UE capability information including the base station power saving mode support capability from the terminal. The UE capability information may specifically include at least one piece of information related to the base station power saving mode, such as information indicating whether the terminal supports the base station power saving mode, information indicating whether the terminal supports carrier aggregation, information indicating whether the terminal supports the SSB transmission simplification operation of the base station, control information related to a frequency band supported by the terminal, control information related to a channel bandwidth supported by the terminal, etc.

[0313] Thereafter, in step 1403, the base station notifies the terminal of the 'SSB-less SCell' configuration. According to the above-described embodiment, the base station can notify the terminal of the 'SSB-less SCell' configuration through the above-described SSB configuration information or additional control information. In addition, information about the 'SSB-less SCell' configuration can be included in the 'RRC reconfiguration' message as described above or in the SCell activation command. In addition, information according to the above-described embodiment can be further included in the 'SSB-less SCell' configuration.

[0314] In step 1404, the base station performs a scheduling operation for the terminal according to the 'SSB-less SCell' setting. According to the above-described embodiment, the base station can determine the QCL of the 'SSB-less SCell' with reference to the 'reference signal' of the 'reference cell'. Alternatively, the base station can receive a measurement report based on the configured reference cell and / or the reference signal, receive an uplink signal or channel transmitted using the transmission power determined based on the configured reference cell and / or the reference signal, or generate a downlink transmission power parameter based on the reference cell and / or the reference signal and transmit it to the terminal. According to the above-described embodiment, the base station schedules to satisfy the MRTD tolerance of the terminal.

[0315] The steps described in FIG. 14 may be omitted, the order changed, or steps not described may be added to implement the present disclosure. The above-described flowchart illustrates exemplary methods that may be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0316] Additionally, the method described in FIGS. 13 and 14 can be performed in combination with at least one of the first to fourth embodiments.

[0317] As described above, a terminal that supports terminal operation according to the base station power saving mode (hereinafter referred to as terminal A) and a terminal that does not (hereinafter referred to as terminal B) can coexist within a cell under the jurisdiction of a base station operating as described above. Terminal A can perform terminal operations according to the specific embodiments described above. Terminal B cannot respond to changes in the base station transmission method according to the base station power saving mode, and thus there is a concern about performance degradation in transmission efficiency, cell capacity, throughput, terminal power consumption, etc. Therefore, if the base station can distinguish whether it is terminal A or terminal B by referring to the UE capability report of the terminal, it can take additional actions to prevent performance degradation of terminal B. For example, the base station can hand over terminal B to an adjacent cell where the base station is in the base station normal mode state, rather than the current cell that will switch to the base station power saving mode.

[0318] The fifth embodiment can be modified in many different ways. For example, a procedure that omits the step where the terminal reports UE capabilities to the base station is also possible.

[0319] FIG. 15 is a diagram illustrating an example of a terminal transceiver in a wireless communication system according to one embodiment of the present disclosure. For convenience of explanation, the illustration and description of devices not directly related to the present disclosure may be omitted.

[0320] Referring to FIG. 15, the terminal may be configured with a transmitter (1504) including an uplink transmission processing block (1501), a multiplexer (1502), and a transmission RF block (1503), a receiver (1508) including a downlink reception processing block (1505), a demultiplexer (1506), and a reception RF block (1507), and a control unit (1509). As described above, the control unit (1509) may control each of the configuration blocks of the receiver (1508) for receiving a data channel or control channel transmitted by the base station and each of the configuration blocks of the transmitter (1504) for transmitting an uplink signal.

[0321] In the transmitter (1504) of the terminal, the uplink transmission processing block (1501) can generate a signal to be transmitted by performing processes such as channel coding and modulation. The signal generated in the uplink transmission processing block (1501) can be multiplexed with another uplink signal by a multiplexer (1502), and then transmitted to the base station after signal processing in the transmission RF block (1503).

[0322] The terminal's receiving unit (1508) demultiplexes the signal received from the base station and distributes it to each downlink receiving processing block. The downlink receiving processing block (1505) can perform processes such as demodulation and channel decoding on the downlink signal of the base station to obtain control information or data transmitted by the base station. The terminal receiving unit (1508) can support the operation of the control unit (1509) by applying the output result of the downlink receiving processing block to the control unit (1509).

[0323] FIG. 16 is a block diagram illustrating an example of a structure of a terminal according to one embodiment of the present disclosure.

[0324] Referring to FIG. 16, the terminal of the present disclosure may include a processor (1630), a transceiver (1610), and a memory (1620). However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more or fewer components than the components described above. In addition, the processor (1630), the transceiver (1610), and the memory (1620) may be implemented in the form of a single chip. According to one embodiment, the transceiver (1610) of FIG. 16 may include the transmitter (1504) and receiver (1508) of FIG. 15. In addition, the processor (1630) of FIG. 16 may include the control unit (1509) of FIG. 15.

[0325] According to one embodiment, the processor (1630) may control a series of processes that enable the terminal to operate according to the embodiments of the present disclosure described above. For example, according to the embodiments of the present disclosure, the components of the terminal may be controlled to perform a transmission and reception method of the terminal according to the 'SSB-less SCell' setting of the base station. There may be one or more processors (1630), and the processors (1630) may perform transmission and reception operations of the terminal in a wireless communication system that applies the operations of the present disclosure described above by executing a program stored in the memory (1620).

[0326] The transceiver (1610) can transmit and receive signals with a base station. The signals transmitted and received with the base station can include control information and data. The transceiver (1610) can be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts a received signal. However, the transceiver (1610) is only one embodiment, and the components of the transceiver (1610) are not limited to the RF transmitter and RF receiver. In addition, the transceiver (1610) can receive a signal through a wireless channel, output it to the processor (1630), and transmit a signal output from the processor (1630) through the wireless channel.

[0327] According to one embodiment, the memory (1620) can store programs and data necessary for the operation of the terminal. In addition, the memory (1620) can store control information or data included in signals transmitted and received by the terminal. The memory (1620) can be configured as a storage medium or a combination of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, the number of memories (1620) can be plural. According to one embodiment, the memory (1620) can store a program for performing transmission and reception operations of the terminal according to the 'SSB-less SCell' settings of the embodiments of the present disclosure described above.

[0328] FIG. 17 is a block diagram illustrating an example of a structure of a base station according to one embodiment of the present disclosure.

[0329] Referring to FIG. 17, the base station of the present disclosure may include a processor (1730), a transceiver (1710), and a memory (1720). However, the components of the base station are not limited to the examples described above. For example, the base station may include more or fewer components than the components described above. Furthermore, the processor (1730), the transceiver (1710), and the memory (1720) may be implemented in the form of a single chip.

[0330] The processor (1730) may control a series of processes so that the base station can operate according to the embodiments of the present disclosure described above. For example, the processor may control components of the base station to perform a method for scheduling a terminal according to an 'SSB-less SCell' setting according to an embodiment of the present disclosure. There may be one or more processors (1730), and the processors (1730) may execute a method corresponding to the 'SSB-less SCell' setting for the terminal of the present disclosure described above by executing a program stored in the memory (1720).

[0331] The transceiver (1710) can transmit and receive signals with the terminal. The signals transmitted and received with the terminal can include control information and data. The transceiver (1710) can be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, an RF receiver that low-noise amplifies the received signal and down-converts the frequency, etc. However, the transceiver (1710) is only one embodiment, and the components of the transceiver (1710) are not limited to the RF transmitter and RF receiver. In addition, the transceiver (1710) can receive a signal through a wireless channel and output it to the processor (1730), and transmit a signal output from the processor (1730) through the wireless channel.

[0332] According to one embodiment, the memory (1720) can store programs and data necessary for the operation of the base station. In addition, the memory (1720) can store control information or data included in signals transmitted and received by the base station. The memory (1720) can be configured as a storage medium or a combination of storage media, such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, there can be a plurality of memories (1720). According to one embodiment, the memory (1720) can store a program for performing a method for scheduling a terminal according to the 'SSB-less SCell' setting of the embodiments of the present disclosure described above.

[0333] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0334] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0335] These programs (software modules, software) may be stored in a non-volatile memory including random access memory, flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc ROMs (CD-ROMs), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0336] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0337] In the specific embodiments of the present disclosure described above, components included in the present disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0338] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples to easily explain the technical contents of the present disclosure and to help understand the present disclosure, and are not intended to limit the scope of the present disclosure. Although specific terms have been used, they are used in a general sense only to easily explain the technical contents of the present disclosure and to help understand the disclosure, and are not intended to limit the scope of the present disclosure. In addition, it will be apparent to those skilled in the art that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, each of the above embodiments can be combined and operated with each other as needed. For example, parts of one embodiment of the present disclosure and another embodiment can be combined with each other to operate a base station and a terminal. In addition, the embodiments of the present disclosure can be applied to other communication systems, and other modifications based on the technical idea of ​​the embodiments can also be implemented.

Claims

1. In a method performed by a terminal of a communication system, A step of receiving information about a reference cell from a base station; A step for verifying that the first secondary cell (SCell) is an SSB-less SCell; A step of identifying a second RS in a QCL (quasi-co-location) relationship with a first reference signal (RS) of the first SCell based on information about the reference cell, A method characterized in that the second RS is an RS of a cell indicated by information about the reference cell.

2. In paragraph 1, A method characterized in that the second reference signal is a synchronization signal block (SSB).

3. In paragraph 1, A method characterized by further comprising the step of transmitting terminal capability information supporting SSB-less SCell to the base station.

4. In paragraph 1, A method characterized in that a maximum receive timing difference (MRTD) required for carrier aggregation (CA) including the SSB-less SCell is equal to or greater than an MRTD required for intra-band CA and smaller than an MRTD required for inter-band CA.

5. In a method performed by a base station of a communication system, A step for verifying that the first secondary cell (SCell) is an SSB-less SCell; and Comprising a step of transmitting information about a reference cell to a terminal, A method characterized in that the first reference signal (RS) and the second RS of the first SCell are in a QCL (quasi-co-location) relationship, and the second RS is an RS of a cell indicated by information about the reference cell.

6. In paragraph 5, A method characterized in that the second reference signal is a synchronization signal block (SSB).

7. In paragraph 5, A method characterized by further comprising the step of receiving terminal capability information supporting SSB-less SCell from the terminal.

8. In paragraph 5, A method characterized in that a maximum receive timing difference (MRTD) required for carrier aggregation (CA) including the SSB-less SCell is equal to or greater than an MRTD required for intra-band CA and smaller than an MRTD required for inter-band CA.

9. At the terminal of the communication system, Transmitter and receiver; and Receive information about the reference cell from the base station, Verify that the first secondary cell (SCell) is an SSB-less SCell, and A control unit configured to identify a second RS in a QCL (quasi-co-location) relationship with a first reference signal (RS) of the first SCell based on information about the reference cell, A terminal, characterized in that the above second RS is an RS of a cell indicated by information about the reference cell.

10. In paragraph 9, A terminal characterized in that the second reference signal is a synchronization signal block (SSB).

11. In paragraph 9, A terminal characterized in that the control unit is further set to transmit terminal capability information supporting SSB-less SCell to the base station.

12. In paragraph 9, A terminal characterized in that a maximum receive timing difference (MRTD) required for carrier aggregation (CA) including the SSB-less SCell is equal to or greater than an MRTD required for intra-band CA and smaller than an MRTD required for inter-band CA.

13. In the base station of the communication system, Transmitter and receiver; and Verify that the first secondary cell (SCell) is an SSB-less SCell, and Includes a control unit set to transmit information about a reference cell to the terminal, A base station, characterized in that the first reference signal (RS) and the second RS of the first SCell are in a QCL (quasi-co-location) relationship, and the second RS is an RS of a cell indicated by information about the reference cell.

14. In paragraph 13, A base station, characterized in that the control unit is further set to receive terminal capability information supporting SSB-less SCell from the terminal.

15. In paragraph 13, A base station, characterized in that a maximum receive timing difference (MRTD) required for carrier aggregation (CA) including the SSB-less SCell is equal to or greater than an MRTD required for intra-band CA and smaller than an MRTD required for inter-band CA.

Images