Method and device for initial access of terminal in wireless communication system composed of multiple carriers

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. At least one embodiment of the present disclosure proposes a method and device for a base station and a terminal to effectively perform an initial access in a multi-carrier system.

Description

Initial connection method and device of a terminal in a wireless communication system composed of multiple carriers

[0001] The present disclosure relates to a communication method of a wireless communication system, and to a method and device for defining efficient frequency use and transmission and reception operations of a terminal.

[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), methods are being considered to achieve even faster transmission speeds and even less ultra-low latency compared to 5G mobile communication technology.

[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] In addition, 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 standardization is being carried out 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 technologies such as the Industrial Internet of Things (IIoT) for intelligent factories to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) that simplifies random access procedures have also been carried out.

[0006] Additionally, standardization is underway for 5G baseline architectures (e.g., Service-based Architecture, Service-based Interface) for incorporating Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, as well as Mobile Edge Computing (MEC), which provides services based on the location of the terminal.

[0007] With the commercialization of 5G mobile communication systems, an explosive increase in connected devices will be connected to communication networks, 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).

[0008] In addition, the development of these 5G mobile communication systems can serve as the basis for the development of new waveforms for coverage guarantee 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, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology for improving the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence)-based communication technology that utilizes AI from the design stage and internalizes end-to-end AI support functions to realize system optimization, and next-generation distributed computing technology that realizes services with complexity that exceeds the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources.

[0009] The disclosed embodiments provide a device and method capable of effectively providing mobile communication services. Specifically, in a multi-carrier system, a base station and a terminal can effectively perform initial connection procedures.

[0010] 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.

[0011] According to one embodiment of the present disclosure, a method performed by a terminal in a communication system is characterized by comprising: receiving a synchronization signal from a base station; receiving system information including uplink frequency information from the base station; identifying a first uplink frequency based on the uplink frequency information; and performing a transmission and reception operation for initial access using the first uplink frequency.

[0012] In addition, in a method performed by a base station in a communication system, the method comprises: a step of transmitting a synchronization signal; a step of confirming a first uplink frequency for performing a transmission and reception operation for initial access; a step of transmitting system information including uplink frequency information related to the first uplink frequency to a terminal; and a step of performing a transmission and reception operation for initial access using the terminal and the first uplink frequency.

[0013] In addition, in a terminal of a communication system, the terminal is characterized by including a transceiver; and a control unit that receives a synchronization signal from a base station, receives system information including uplink frequency information from the base station, confirms a first uplink frequency based on the uplink frequency information, and performs a transmission and reception operation for initial access using the first uplink frequency.

[0014] In addition, in a base station of a communication system, it is characterized by including a transceiver; and a control unit that transmits a synchronization signal, confirms a first uplink frequency for performing a transmission and reception operation for initial access, transmits system information including uplink frequency information related to the first uplink frequency to a terminal, and controls the terminal to perform a transmission and reception operation for initial access using the first uplink frequency.

[0015] Embodiments of the present disclosure provide a transmission / reception device and method for a terminal and a base station that enhance frequency utilization efficiency in a mobile communication system. Specifically, according to at least one embodiment of the present disclosure, a base station and a terminal in a multi-carrier system can effectively perform an initial connection procedure.

[0016] 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.

[0017] FIG. 1 is a diagram showing the basic structure of a time-frequency resource domain of a 5G system according to one embodiment of the present disclosure.

[0018] FIG. 2 is a diagram illustrating a random access procedure according to one embodiment of the present disclosure.

[0019] FIG. 3 is a diagram illustrating a procedure for a terminal to report terminal capability information to a base station according to one embodiment of the present disclosure.

[0020] FIG. 4 is a diagram showing an example of bandwidth portion settings according to one embodiment of the present disclosure.

[0021] FIG. 5 is a diagram showing the interrelationship between frequency bands and coverage according to one embodiment of the present disclosure.

[0022] FIG. 6 is a diagram showing a frequency relationship according to one embodiment of the present disclosure.

[0023] FIG. 7 is a diagram showing a frequency relationship according to one embodiment of the present disclosure.

[0024] FIG. 8 is a diagram showing a frequency relationship according to one embodiment of the present disclosure.

[0025] FIG. 9 is a diagram showing a frequency relationship according to one embodiment of the present disclosure.

[0026] FIG. 10 is a diagram showing a frequency relationship according to one embodiment of the present disclosure.

[0027] FIG. 11 is a diagram illustrating a signal transmission and reception method between a terminal and a base station according to one embodiment of the present disclosure.

[0028] FIG. 12 is a diagram illustrating another signal transmission and reception method between a terminal and a base station according to one embodiment of the present disclosure.

[0029] FIG. 13 is a diagram illustrating another signal transmission and reception method between a terminal and a base station according to one embodiment of the present disclosure.

[0030] FIG. 14 is a diagram illustrating a terminal procedure according to one embodiment of the present disclosure.

[0031] FIG. 15 is a diagram illustrating a base station procedure according to one embodiment of the present disclosure.

[0032] FIG. 16 is a diagram showing a terminal transceiver device according to one embodiment of the present disclosure.

[0033] FIG. 17 is a block diagram illustrating the structure of a terminal according to one embodiment of the present disclosure.

[0034] FIG. 18 is a block diagram illustrating the structure of a base station according to one embodiment of the present disclosure.

[0035] 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.

[0036] 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.

[0037] 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).

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] In the following description, the terms "physical channel" and "physical 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 can also be used to refer to data. That is, in the present disclosure, the expression "transmitting a physical channel" can be interpreted equivalently to the expression "transmitting data or a signal through a physical channel."

[0043] Hereinafter, in the present disclosure, higher 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. Higher layer signaling can be understood as a master information block (MIB), a system information block (SIB), radio resource control (RRC) signaling, or a media access control (MAC) control element (CE).

[0044] For convenience of explanation, this disclosure uses terms and names defined in the 3GPP NR (New Radio: 5th generation mobile communications standard) standard. However, this disclosure is not limited to these terms and names and can be equally applied to systems conforming to other standards. For example, for 6G systems, which are still in the early stages of standardization discussions, the terms and names defined in the 5G system can be generalized and used to describe the operation of the 6G system unless otherwise specified.

[0045] 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.

[0046] While existing mobile communication systems have focused on conventional voice / data communications, the 5G system aims to satisfy various services and requirements, such as enhanced mobile broadband (eMBB) services to improve existing voice / data communications, ultra-reliable and low latency communication (URLLC) services, and massive machine type communication (MTC) services that support large-scale machine-type communication.

[0047] While the transmission bandwidth of existing mobile communication systems, such as LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)) and LTE-A (LTE-Advanced or E-UTRA Evolution), is limited to a maximum of 20MHz per single carrier, the 5G system aims to provide ultra-high-speed data services of up to several Gbps by utilizing a much wider ultra-wide bandwidth. Accordingly, the 5G system is considering an ultra-high frequency band from several GHz up to 100 GHz as its operating frequency, where it is relatively easy to secure ultra-wide bandwidth frequencies. Additionally, it is possible to secure wide bandwidth frequencies for the 5G system through frequency reallocation or allocation among the frequency bands included in the hundreds of MHz to several GHz used in existing mobile communication systems.

[0048] 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.

[0049] To overcome the drawback of reduced coverage in ultra-high frequency bands, beamforming technology is applied. This technology focuses the radiated energy of radio waves toward a predetermined target point using multiple antennas, thereby increasing the transmission range. Specifically, a signal using beamforming technology has a relatively narrow beamwidth, and the radiated energy is concentrated within this narrowed beamwidth, increasing the transmission range. Beamforming can be applied to both the transmitter and receiver. In addition to increasing coverage, beamforming also reduces interference in areas outside the beamforming direction. For beamforming to function properly, accurate measurement and feedback of the transmission and reception beams are required. Beamforming can be applied to control or data channels that correspond one-to-one between a given terminal and a base station. Furthermore, beamforming can be applied to common signals transmitted by a base station to multiple terminals within a system, such as synchronization signals, physical broadcast channels (PBCHs), and control and data channels for transmitting system information, to increase coverage. When applying beamforming technology to a common signal, beam sweeping technology, which transmits the signal by changing the beam direction, is additionally applied so that the common signal can reach terminals located at any location within the cell.

[0050] Another requirement for 5G systems is ultra-low latency services, with transmission delays of approximately 1ms between transmitters and receivers. One way to reduce transmission delay is to design a frame structure based on a short transmission time interval (TTI), which is shorter than that of LTE and LTE-A. A TTI is the basic unit of time used 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, to meet the requirements for ultra-low latency services, shorter TTIs such as 0.5ms, 0.25ms, and 0.125ms are possible, which are shorter than those of existing LTE and LTE-A systems.

[0051] FIG. 1 is a diagram illustrating the basic structure of a time-frequency resource domain of a 5G system according to one embodiment of the present disclosure. That is, FIG. 1 is a diagram illustrating the basic structure of a time-frequency resource domain, which is a radio resource domain through which data or control channels of a 5G system are transmitted.

[0052] 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. The dog symbols (102) come 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 bandwidth is a total of N BW It can be composed of a subcarrier (104).

[0053] 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) is a resource block in the frequency domain. can be defined as a series of consecutive subcarriers (110). In the 5G system = 12, and the data rate can increase in proportion to the number of RBs scheduled to the terminal.

[0054] 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.

[0055] 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. Extended CP can be applied to systems with relatively long transmission distances compared to general CP, allowing for maintaining orthogonality between symbols. In the case of general CP, since the ratio of CP length to symbol length is maintained at a constant value, the overhead due to CP can be maintained constant regardless of the subcarrier spacing. 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.

[0056] In 5G systems, various frame structures can be supported by adjusting the subcarrier spacing to meet diverse services and requirements. For example,

[0057] - 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.

[0058] - From a transmission time perspective, a large subcarrier spacing shortens the symbol length in the time domain, and consequently, the slot length shortens, which is advantageous for supporting ultra-low delay services such as URLLC.

[0059] - 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.

[0060] 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 in 5G systems.

[0061] μ cyclic prefix015normal130normal260normal, extended3120normal4240normal

[0062] 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.

[0063] μ 0141011142022144043148084141601651432032

[0064] 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 ( ) is indicated.

[0065] μ 212404

[0066] 5G systems can satisfy diverse user requirements through coexistence or dual-mode operation with existing LTE and / or LTE-A (hereinafter referred to as LTE / LTE-A) systems. For example, existing LTE / LTE-A systems can provide stable system operation to terminals, while 5G systems can provide enhanced services to terminals. Therefore, the frame structure of a 5G system must at least include the LTE / LTE-A frame structure or a set of essential parameters (subcarrier spacing = 15 kHz).

[0067] 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.

[0068] 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.

[0069] 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.

[0070] Similar to the coexistence of 5G and LTE / LTE-A mentioned above, system design for coexistence of 6G, which will arrive in the future as communication systems evolve, and existing systems such as 5G or LTE / LTE-A may be required.

[0071] 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.

[0072] During the initial access phase, when a terminal first accesses the system, the terminal can synchronize downlink time and frequency using a synchronization signal transmitted by the base station through cell search and acquire a cell identifier (cell ID). Using the acquired cell ID, the terminal can receive a physical broadcast channel (PBCH) and acquire essential system information, the master information block (MIB), from the PBCH. The MIB may include the following information:

[0073] MIB ::= SEQUENCE {

[0074] systemFrameNumber BIT STRING (SIZE (6));

[0075] subCarrierSpacingCommon ENUMERATED {scs15or60, scs30or120},

[0076] ssb-SubcarrierOffset INTEGER (0..15);

[0077] dmrs-TypeA-Position ENUMERATED {pos2, pos3},

[0078] pdcch-ConfigSIB1 PDCCH-ConfigSIB1,

[0079] cellBarred ENUMERATED {barred, notBarred},

[0080] intraFreqReselection ENUMERATED {allowed, notAllowed},

[0081] spare BIT STRING (SIZE (1))

[0082] }

[0083] For example, the essential system information may include at least one of information for receiving system information, such as information on the time domain and / or frequency domain location of a synchronization signal received by the terminal, control information for the terminal to receive system information (or system information block, SIB) transmitted by the base station (which may be information for scheduling a data channel for receiving system information), information on whether the cell is accessible, and information on the SCS of the cell. The essential system information may be referred to as system information.

[0084] Additionally, the terminal can obtain cell-common transmission and reception-related control information by receiving system information 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, common control information for various physical channels and signals (at least one of a channel and signal, such as an uplink control channel, an uplink data channel, a downlink control channel, and a downlink data channel, a physical signal for obtaining uplink channel state information, a physical signal for obtaining downlink channel state information, and a physical signal for demodulating a physical channel). The control information may be configuration information for each channel or signal. The system information may be referred to as, for example, SIB1 or RMSI (remaining minimum system information).

[0085] The synchronization signal is a signal that serves as a reference for cell search, and the subcarrier spacing can be applied to suit the channel environment, such as phase noise, for each frequency band. In the case of data channels or control channels, the subcarrier spacing can be applied differently depending on the service type in order to support various services as described above. In the 5G system, the combination consisting of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH) is called an SS / PBCH block or SSB.

[0086] In addition to the initial connection procedure described above, the terminal may also receive SSBs to determine whether the radio link quality of the current cell is maintained at a certain level or higher. Furthermore, in a procedure where the terminal performs a handover from the current cell to an adjacent cell, the terminal may also receive SSBs from the adjacent cell to determine the radio link quality of the adjacent cell and obtain time / frequency synchronization with the adjacent cell.

[0087] 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. 2.

[0088] FIG. 2 is a diagram illustrating a random access procedure according to one embodiment of the present disclosure.

[0089] Referring to FIG. 2, in the first step (210) 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.

[0090] In the second step (220), the base station transmits a message including 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 (210). The terminal receives control information for scheduling the message on a downlink control channel and receives the message on a downlink data channel based on the control information. The message transmitted in the second step may be referred to as message 2, a response to the random access preamble, or a random access response. In addition, the base station may transmit the message by including, as scheduling information, an uplink resource to be used by the terminal to transmit a response message (message 3) to message 2 and a power control command to be applied to the response message. The scheduling information may include control information for the uplink transmission beam of the terminal. In addition, the message may further include a temporary identifier of the terminal to be used during the random access procedure. The information included in the message is merely an example, and one or more of the above-described information may be included in message 2.

[0091] If the terminal does not receive message 2, which is scheduling information for message 3, from the base station within a predetermined time in the second step (220), the first step (210) can be performed again. If the first step (210) 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).

[0092] In the third step (230), 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 (220). The transmission timing of the uplink data channel for transmitting Message 3 may follow the uplink transmission timing control command received from the base station in the second step (220). In addition, the transmission power of the uplink data channel for transmitting Message 3 may be determined by considering the power control command received from the base station in the second step (220) 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. For example, the message 3 may include a higher layer message for the terminal to access the network.

[0093] In step 4 (240), 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 (230) to the terminal. If the terminal receives the signal transmitted by the base station in step 4 (240) 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).

[0094] If the data transmitted by the terminal in step 3 (230) 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 (240) within a certain period of time, it may determine that the random access procedure has failed and restart from step 1 (210).

[0095] The four-step random access procedure described above is merely an example, and the information between the terminal and the base station described above may also be transmitted via messages other than the four-step message described above. For example, the terminal may simultaneously or sequentially transmit to the base station one or more messages containing at least one of the information in message 1 and 3, and the base station may simultaneously or sequentially transmit to the terminal one or more messages containing at least one of the information in message 2 and 4.

[0096] 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 terminal capability information (UE capability information) from the connected terminal and can adjust scheduling by referring to the UE capability information. Through the UE capability information, the terminal can inform the base station whether it supports a certain function and the maximum allowable value of the function supported by the terminal. Therefore, the UE capability information reported by each terminal to the base station may have different values ​​for each terminal.

[0097] For example, a terminal may report terminal capability information including at least a portion of the following control information to a base station as terminal capability information.

[0098] - Control information related to frequency bands supported by the terminal

[0099] - Control information related to channel bandwidth supported by the terminal

[0100] - Control information related to the maximum modulation method supported by the terminal

[0101] - Control information related to the maximum number of beams supported by the terminal

[0102] - Control information related to the maximum number of layers supported by the terminal

[0103] - Control information related to CSI reporting supported by the terminal

[0104] - Control information on whether the terminal supports frequency hopping

[0105] - Bandwidth-related control information when supporting carrier aggregation (CA)

[0106] - Control information on whether cross carrier scheduling is supported when carrier aggregation is supported.

[0107] FIG. 3 is a diagram illustrating a procedure for a terminal to report terminal capability information to a base station according to one embodiment of the present disclosure.

[0108] Referring to FIG. 3, at step 310, the base station (302) can transmit a terminal capability information request message to the terminal (301). In response to the terminal capability information request from the base station, the terminal transmits terminal capability information to the base station at step 320.

[0109] Next, the bandwidth part (BWP) setting in the 5G communication system will be specifically explained with reference to the drawing.

[0110] Figure 4 is a diagram illustrating an example of bandwidth portion settings in a 5G communication system.

[0111] Figure 4 shows an example in which the UE bandwidth (400) is set to two bandwidth portions, namely, bandwidth portion #1 (BWP#1, 401) and bandwidth portion #2 (BWP#2, 402). The base station can set one or more bandwidth portions to the UE, and can set the information in Table 4 below for each bandwidth portion.

[0112] BWP ::= SEQUENCE {bwp-Id BWP-Id,(bandwidth part identifier)locationAndBandwidth INTEGER (1..65536),(bandwidth part location)subcarrierSpacing ENUMERATED {n0, n1, n2, n3, n4, n5},(subcarrier spacing)cyclicPrefix ENUMERATED { extended}(cyclic prefix)}

[0113] Of course, the above examples are not limited, and in addition to the above-mentioned configuration information, various parameters related to the bandwidth portion may be configured for the terminal. The above-mentioned information may be transmitted from the base station to the terminal via higher-layer signaling, such as RRC signaling. At least one of the configured bandwidth portions may be activated. Whether or not the configured bandwidth portion is activated may be semi-statically transmitted from the base station to the terminal via RRC signaling or dynamically transmitted via DCI.

[0114] According to some embodiments, a terminal before RRC connection can be configured with an initial bandwidth portion (initial BWP) for initial access from a base station via MIB. More specifically, during the initial access phase, the terminal can receive configuration information about a control resource set (CORESET) and a search space, through which a physical downlink control channel (PDCCH) for receiving system information required for initial access can be transmitted, via MIB. The CORESET and search space configured via MIB can each be regarded as identifier (ID) 0 (CORESET 0, search space 0). The base station can notify the terminal of configuration information, such as frequency allocation information, time allocation information, and subcarrier spacing settings, for CORESET #0 via MIB. In addition, the base station can notify the terminal of configuration information about a monitoring cycle and monitoring occasion for CORESET #0, i.e., configuration information for search space #0, via MIB. The terminal may consider the frequency range set to CORESET#0 obtained from the MIB as the initial bandwidth portion for initial connection. At this time, the identifier (ID) of the initial bandwidth portion may be considered as 0.

[0115] The settings for the bandwidth portion supported by the above 5G system can be used for various purposes.

[0116] In some embodiments, when the bandwidth supported by a terminal is smaller than the system bandwidth, this can be supported through bandwidth portion configuration. For example, the base station can configure the bandwidth portion frequency location (configuration information 2) for the terminal, thereby allowing the terminal to transmit and receive data at a specific frequency location within the system bandwidth.

[0117] Additionally, in some embodiments, a base station may configure multiple bandwidth segments for a terminal to support different subcarrier spacing settings. For example, to support data transmission and reception using both 15 kHz and 30 kHz subcarrier spacings for a given terminal, two bandwidth segments may be configured with subcarrier spacings of 15 kHz and 30 kHz, respectively. The different bandwidth segments may be frequency division multiplexed (FDM), and when data is to be transmitted or received using a specific subcarrier spacing, the bandwidth segment configured for the corresponding subcarrier spacing may be activated.

[0118] Furthermore, in some embodiments, the base station may configure bandwidth portions with different bandwidth sizes for the terminal to reduce power consumption. For example, if the terminal supports a very large bandwidth, such as 100 MHz, and constantly transmits and receives data within that bandwidth, this may result in significant power consumption. In particular, monitoring unnecessary downlink control channels with a large bandwidth of 100 MHz in a traffic-free environment may be very inefficient in terms of power consumption. To reduce power consumption, the base station may configure a relatively small bandwidth portion for the terminal, such as 20 MHz. In a traffic-free environment, the terminal may perform monitoring operations in the 20 MHz bandwidth portion, and when data is generated, it may transmit and receive data in the 100 MHz bandwidth portion according to instructions from the base station.

[0119] In the method for setting the bandwidth portion, terminals prior to RRC connection can receive configuration information for the initial bandwidth portion through the MIB during the initial access phase. More specifically, the terminal can set a CORESET for a downlink control channel on which a DCI for scheduling an SIB can be transmitted from the MIB of the PBCH. The bandwidth of the CORESET set by the MIB can be regarded as the initial bandwidth portion, and the terminal can receive the PDSCH on which the SIB is transmitted through the set initial bandwidth portion. In addition to receiving the SIB, the initial bandwidth portion can also be utilized for paging and random access.

[0120] Next, we will specifically explain downlink control information (DCI) in the 5G system.

[0121] 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 fallback DCI format and a non-fallback DCI format 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.

[0122] 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 the UE's identity identifier (e.g., radio network temporary identifier (RNTI). 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 over the PDCCH, it verifies the CRC using the assigned RNTI. If the CRC verification result is correct, the UE can determine that the message has been transmitted to the UE.

[0123] For example, the DCI scheduling the PDSCH for system information may be scrambled with SI-RNTI. The DCI scheduling the PDSCH for a RAR message may be scrambled with RA-RNTI. The DCI scheduling the PDSCH for a paging message may be scrambled with P-RNTI. The DCI notifying the Slot Format Indicator (SFI) may be scrambled with SFI-RNTI. The DCI notifying the Transmit Power Control (TPC) may be scrambled with TPC-RNTI. The DCI scheduling the UE-specific PDSCH or PUSCH may be scrambled with C-RNTI (cell RNTI).

[0124] 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.

[0125] The base station can transmit downlink data to the terminal via the Physical Downlink Shared 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 DCI transmitted via the PDCCH.

[0126] 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.

[0127] The time-frequency resource to which the PDCCH is mapped is called a CORESET. A CORESET can be configured for all or part of the frequency resources of the bandwidth supported by the terminal 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 terminal through higher layer signaling (e.g., system information, MIB, RRC signaling). Configuring a CORESET to the terminal may mean providing information such as the CORESET identifier, the frequency location of the CORESET, and the symbol length of the CORESET. The information that the base station provides to the terminal to configure the CORESET may include at least some of the information included in Table 5.

[0128] 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)}

[0129] 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.

[0130] 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 for the corresponding CORESET based on whether to use interleaved or non-interleaved transmission as configured by the base station, as shown in Table 6 below.

[0131] [Table 6]

[0132]

[0133] 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.

[0134] 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.

[0135] Search spaces can be classified into a common search space (CSS) and a UE-specific search space (USS). A certain group of UEs or all UEs can monitor the common search space of the PDCCH to receive cell-common control information, such as dynamic scheduling for the System Information Block (SIB) or paging messages. For example, a UE can receive scheduling allocation information for the PDSCH for receiving system information by monitoring 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 the UE by monitoring the UE-specific search space of the PDCCH. The UE-specific search space can be defined UE-specifically as a function of the UE ID and various system parameters.

[0136] 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 the information in Table 7 below.

[0137] SearchSpace ::= SEQUENCE {searchSpaceId SearchSpaceId,(search space identifier)controlResourceSetId ControlResourceSetId OPTIONAL, -- Cond SetupOnly(CORESET identifier)monitoringSlotPeriodicityAndOffset CHOICE {(monitoring slot level 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}.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] - 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

[0142] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0143] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0144] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0145] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0146] 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.

[0147] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0148] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0149] RNTIs may follow the following definitions and uses:

[0150] C-RNTI (cell RNTI): For terminal-specific PDSCH or PUSCH scheduling purposes.

[0151] TC-RNTI (temporary cell RNTI): For terminal-specific PDSCH scheduling purposes

[0152] CS-RNTI (configured scheduling RNTI): Used for semi-static terminal-specific PDSCH scheduling.

[0153] RA-RNTI (random access RNTI): Used for PDSCH scheduling in the random access phase.

[0154] P-RNTI (paging RNTI): Used for scheduling PDSCH where paging is transmitted.

[0155] SI-RNTI (system information RNTI): Used for scheduling PDSCH where system information is transmitted.

[0156] INT-RNTI (interruption RNTI): Used to indicate whether puncturing is occurring on the PDSCH.

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

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

[0159] TPC-SRS-RNTI (transmit power control for SRS RNTI): Used to indicate power adjustment commands for SRS (sounding reference signal)

[0160] The DCI formats described above can follow the definitions shown in Table 8 below.

[0161] 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

[0162] 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.

[0163] [Mathematical Formula 1]

[0164]

[0165] - L: Integration level

[0166] - n CI : Carrier index

[0167] - n CCE,p : Total number of CCEs present in CORESET p

[0168] - : slot index

[0169] - : Number of PDCCH candidates for aggregation level L

[0170] - = 0, ..., -1: PDCCH candidate index of aggregation level L

[0171] - l = 0, ..., L -1

[0172] - , 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

[0173] - n RNTI : Terminal identifier

[0174] The value can be 0 for a common search space.

[0175] 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.

[0176] Below, we will specifically describe how a terminal measures channel conditions and reports them to a base station in a 5G communication system.

[0177] Channel state information (CSI) may include the following information:

[0178] - Channel quality indicator (CQI): CQI index indication information consisting of a modulation method and coding rate that satisfies the minimum reception error rate of a predefined PDSCH.

[0179] - Precoding matrix indicator (PMI): Precoding matrix indicator information selected by the terminal.

[0180] - CRI (CSI-RS resource indicator): CSI-RS information measured by the terminal

[0181] - RI (rank indicator): Rank indication information selected by the terminal

[0182] - LI (layer indicator): Indicative information for the best layer among the precoding matrices reported by the terminal.

[0183] - SSBRI (SS / PBCH block resource indicator): SSB information measured by the terminal

[0184] - L1-RSRP (reference signal received power): L1 RSRP information measured by the terminal

[0185] The base station can control time and frequency resources for the aforementioned CSI measurement and reporting of the terminal.

[0186] 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 bandwidth part in which 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).

[0187] 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 control element (MAC CE).

[0188] Aperiodic CSI reporting can be triggered by the CSI request field of the aforementioned DCI format 0_1 ​​corresponding to the scheduling DCI for PUSCH.

[0189] As another way to support ultra-high-speed data services, 5G systems can support ultra-wide bandwidth signal transmission and reception of tens to hundreds of MHz, or even several GHz. The ultra-wide bandwidth signal transmission and reception can be supported through a single component carrier (CC), or through CA technology that combines multiple component carriers. Carrier aggregation technology can increase the total frequency bandwidth by combining individual component carriers with relatively small bandwidths when a mobile communication service provider is unable to secure a frequency with sufficient bandwidth to provide ultra-high-speed data services through a single component carrier, thereby enabling ultra-high-speed data services.

[0190] As mentioned above, the frequency band utilized by 5G systems is wide, ranging from hundreds of MHz to tens of GHz. Figure 5 shows the interrelationship among frequency bands, coverage, and bandwidth. Figure 5 shows the frequency bands of low band (501), mid band (502), high band (503), and ultra high band (504). In general, the lower the frequency band, the greater the coverage due to relatively small path loss, and the higher the frequency band, the smaller the coverage due to relatively high path loss. In the low frequency band, the frequency available for mobile communication is fragmented, resulting in a small bandwidth, whereas in the high frequency band, it is relatively easy to secure a wide bandwidth, making it 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, the next-generation mobile communication system, 6G (6 th In mobile communication systems, the 7 to 15 GHz band, called the upper midband, is being considered as one of the candidate frequencies.

[0191] 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 secured 5G frequency bands to operate a combined LTE and 5G system. As another example, a mobile carrier can secure frequency bands for a 5G system across multiple bands and then combine these bands to provide mobile communication services through 5G carrier aggregation (CA). Similarly, a 6G mobile communication system can combine 6G frequencies with existing 4G or 5G frequencies, or combine 6G frequencies to provide mobile communication services through 6G CA.

[0192] As described above, since characteristics such as coverage and bandwidth vary depending on the frequency band, mobile communication services that combine multiple frequency bands are becoming more active than mobile communication services that rely on a single frequency band.

[0193] The operation of the system proposed in the present disclosure is described below through specific examples.

[0194] The main point of the present invention is to define operations related to a terminal and a base station, enabling the application of a mobile communication service combining multiple frequency bands from the initial access procedure of the terminal. The initial access procedure can be understood as including the transmission and reception of synchronization signals and system information between the terminal and the base station, as well as a random access procedure between the terminal and the base station. The terminal can then request an attach to the network, and after the attach procedure is completed, it can transmit and receive packets (or data) through the network.

[0195] The main points of the present invention are explained below with reference to FIGS. 6, 7, 8, 9 and 10.

[0196] FIG. 6 is a diagram illustrating an example of the correlation between downlink frequencies and uplink frequencies in the initial access and random access procedure stages of a terminal in an existing system. According to FIG. 6, one downlink frequency (601, or downlink frequency band, which can be used interchangeably hereinafter) is connected to one uplink frequency (611, or uplink frequency band, which can be used interchangeably hereinafter), indicating that the connection relationship between the downlink frequency and the uplink frequency is 1:1. For example, a terminal in the initial access stage acquires SSB and system information through the downlink frequency (601) during a cell search process. Then, when the terminal performs a random access procedure, the terminal performs uplink transmission, such as a random access preamble or message 3, in the random access procedure, through the uplink frequency (611) connected to the downlink frequency, and performs downlink reception, such as message 2 or message 4, in the random access procedure, through the downlink frequency (601). The base station can provide control information regarding the uplink frequency to the terminal through the system information. In the case of an FDD system, the downlink frequency and uplink frequency are physically different frequencies. In the case of a TDD system, the downlink frequency and uplink frequency are physically the same frequency.

[0197] FIGS. 7, 8, 9, and 10 are diagrams illustrating an example in which a processing unit (processing unit, 720) including a plurality of downlink frequencies and a plurality of uplink frequencies is configured according to the main gist of the present invention, and an initial connection and random access procedure of a terminal are performed within the processing unit. FIGS. 7 to 10 illustrate an example in which two downlink frequencies and two uplink frequency bands exist within the processing unit, and one downlink frequency and one uplink frequency are connected. However, such a processing unit is merely an example, and it is possible for there to be more than one downlink frequency or uplink frequency within the processing unit. FIG. 7 illustrates a 1:1 correspondence between one downlink frequency and one uplink frequency, but instead, it is also possible for a correspondence of A:B (A≥1, B≥1) to exist between the downlink frequency and the uplink frequency.

[0198] The above downlink frequency or uplink frequency may exist in different frequency bands of FIG. 5 or may exist in the same frequency band. For example, downlink frequency 1 may exist in the low band (501) and downlink frequency 2 may exist in the mid band (502), or both downlink frequencies 1 and 2 may exist in the mid band (502). In addition, it is possible that corresponding downlink frequencies and uplink frequencies exist in different frequency bands of FIG. 5 or may exist in the same frequency band. For example, downlink frequency 1 may exist in the low band (501) and uplink frequency 1 may exist in the mid band (502), or both downlink frequency 1 and uplink frequency 1 may exist in the mid band (502).

[0199] FIG. 7 is a diagram illustrating frequency relationships according to one embodiment of the present disclosure. The example of FIG. 7 illustrates a case where the processing unit (720) is configured with downlink frequency 1 (701) and uplink frequency 1 (711) connected thereto, and downlink frequency 2 (702) and uplink frequency 2 (712) connected thereto. Generalizing this, the processing unit may be configured with M downlink frequencies and N uplink frequencies (M ≥ 1, N ≥ 1). In this case, as illustrated in FIG. 7, one uplink frequency and one downlink frequency may be connected, or one uplink frequency and one or more downlink frequencies may be connected, or one downlink frequency and one or more downlink frequencies may be connected, as illustrated in FIG. 9.

[0200] In this specification, the existence of a connection relationship between an uplink frequency and a downlink frequency means that a terminal and a base station can transmit and receive channels and signals (for initial access) using the uplink frequency and the downlink frequency. For example, when one downlink frequency is connected to multiple uplink frequencies, a terminal and a base station can transmit and receive channels and signals (for initial access) using the one downlink frequency and one of the multiple uplink frequencies. The connection relationship can be confirmed by the connection between the uplink frequency and the downlink frequency illustrated in FIGS. 7 to 10.

[0201] In the example of FIG. 7, when the terminal acquires SSB and system information through downlink frequency 1 (701), the terminal performs uplink transmission according to a random access procedure, such as a random access preamble or message 3, through uplink frequency 1 (711) connected to downlink frequency 1 (701), and performs downlink reception according to a random access procedure, such as message 2 or message 4, through downlink frequency 1 (701). The base station can provide the terminal with control information regarding uplink frequency 1 (711) through the system information of downlink frequency 1 (701). If the terminal acquires SSB and system information through downlink frequency 2 (702), the terminal performs uplink transmission according to a random access procedure, such as a random access preamble or message 3, through uplink frequency 2 (712) connected to downlink frequency 2 (702), and performs downlink reception according to a random access procedure, such as message 2 or message 4, through downlink frequency 2 (702). The base station can provide control information regarding uplink frequency 2 (712) to the terminal through system information of the above downlink frequency 2 (702).

[0202] The base station can stop (OFF) or maintain (ON) part or all of the transmission and reception operations through the downlink frequency or uplink frequency within the processing unit as needed. FIG. 8 is a diagram showing another frequency relationship according to an embodiment of the present disclosure. FIG. 8 shows a case where the transmission and reception operations through downlink frequency 1 (801) and uplink frequency 1 (811) are turned OFF, and the transmission and reception operations through downlink frequency 2 (802) and uplink frequency 2 (812) are turned ON, within the processing unit (820) configured in the same manner as FIG. 7. Accordingly, the terminal performs the initial access and random access procedures through downlink frequency 2 (802) and uplink frequency 2 (812). The base station can provide control information regarding uplink frequency 2 (812) to the terminal through the system information of the downlink frequency 2 (802). From the base station's perspective, the OFF operation can be expected to have the effect of reducing base station power consumption. The base station can signal to the terminal whether the above OFF operation is applied for each downlink frequency and uplink frequency. For example, the base station can signal to the terminal that downlink frequency 1 (801) and uplink frequency 1 (811) are turned OFF or deactivated through upper layer signaling.

[0203] FIG. 9 is a diagram showing another frequency relationship according to an embodiment of the present disclosure. FIG. 9 shows a case where, within a processing unit (920) configured in the same manner as FIG. 7, a base station transmission operation through downlink frequency 1 (901) is turned OFF, and transmission / reception operations through uplink frequency 1 (911), downlink frequency 2 (902), and uplink frequency 2 (912) are turned ON. In this case, the terminal acquires SSB and system information through downlink frequency 2 (902), performs uplink transmission according to a random access procedure through uplink frequency 1 (911) or uplink frequency 2 (912), and performs downlink reception according to a random access procedure through the downlink frequency 2 (902).

[0204] The base station may provide the terminal with control information regarding the uplink frequency 1 (911) and uplink frequency 2 (912) as candidate frequencies for uplink transmission in a random access procedure through the system information of the downlink frequency 2 (902). In this case, the terminal may use at least one of the following methods to determine the uplink frequency for uplink signal transmission.

[0205] - Uplink frequency determination method 1: The base station can provide information related to the uplink frequency to be used by the terminal for uplink transmission through system information transmitted via the downlink frequency 2 (902). For example, the base station can transmit to the terminal information indicating the uplink frequency to be used by the terminal for uplink transmission through the system information. Alternatively, the base station can indirectly instruct the terminal to use a specific uplink frequency by providing information related to the uplink frequency to be used by the terminal for uplink transmission through the system information.

[0206] - Uplink frequency determination method 2: The terminal compares the signal strength of the SSB received through the downlink frequency 2 (902) with a predetermined threshold value, and selects the uplink frequency 1 (911) if the received signal strength of the SSB is less than (or greater than or equal to) the threshold value, and selects the uplink frequency 2 (912) if the received signal strength of the SSB is greater than or equal to (or less than) the threshold value. Control information on which uplink frequency to select based on the comparison of the received signal strength of the SSB with the threshold value may be included in the system information. For example, the control information may include information on the threshold value, or the threshold value may be a predetermined value that varies depending on the frequency band of the downlink frequency or / and the uplink frequency.

[0207] - Uplink frequency determination method 3: The base station can signal to the terminal which method to apply between the above-mentioned uplink frequency determination method 1 and the above-mentioned uplink frequency determination method 2. The signaling can be transmitted as system information.

[0208] From the base station's perspective, the OFF operation can be expected to reduce base station power consumption. The base station can signal to the terminal whether the OFF operation is applied for each downlink frequency and uplink frequency. For example, the base station can signal to the terminal that downlink frequency 1 (901) has been turned off or deactivated through upper layer signaling.

[0209] Fig. 10 is a diagram showing another frequency relationship according to one embodiment of the present disclosure. Fig. 10 shows a case where, within a processing unit (1020) configured in the same manner as Fig. 7, a base station transmission operation through downlink frequency 1 (1001) and a base station reception operation through uplink frequency 2 (1012) are turned OFF, and a base station reception operation through uplink frequency 1 (1011) and a base station transmission operation through downlink frequency 2 (1002) are turned ON.

[0210] In this case, the terminal acquires SSB and system information through downlink frequency 2 (1002), performs uplink transmission according to a random access procedure through uplink frequency 1 (1011), and performs downlink reception according to a random access procedure through the downlink frequency 2 (1002).

[0211] The base station can provide control information regarding the uplink frequency 1 (1011) to the terminal through the system information of the downlink frequency 2 (1002). From the base station's perspective, the OFF operation can be expected to have the effect of reducing the base station's power consumption. The base station can inform the terminal of whether the OFF operation is applied through signaling for each of the downlink frequency and the uplink frequency. For example, the base station can inform the terminal that the downlink frequency 2 (1002) and the uplink frequency 2 (1011) are OFF or deactivated through upper layer signaling.

[0212] The above embodiments are distinguished for convenience in order to explain implementations according to the present disclosure, and all or part of the embodiments may be selectively combined and configured to achieve various implementations through the present disclosure.

[0213] Hereinafter, a description of each specific embodiment is provided. The present invention may include multiple embodiments, and each embodiment may be implemented independently, but as long as they are not mutually exclusive, the multiple embodiments may be implemented in combination with each other. Such combinations encompass various modifications and variations of the present invention, and may be implemented in various ways depending on technical needs or application environments. Even if the multiple embodiments use different approaches to achieve the purpose of the invention, as long as the embodiments of the present invention are not technically mutually exclusive, they may be used simultaneously or complementarily. Such combinations may be modified in various ways depending on technical requirements or specific application cases, and the present invention may encompass various embodiments that include such modifications and combinations.

[0214] <Example 1>

[0215] The first embodiment describes a specific signaling method when applying a mobile communication service combining multiple frequency bands to the initial access procedure of a terminal.

[0216] FIG. 11 is a diagram illustrating a signal transmission and reception method between a terminal and a base station according to one embodiment of the present disclosure. The operation of the first embodiment will be described below with reference to FIG. 11. FIG. 11 assumes a 'processing unit' composed of downlink frequency 1 (1105), uplink frequency 1 (1106), downlink frequency 2 (1115), and uplink frequency 2 (1116). In addition, it is assumed that the base station has turned off the base station transmission operation at downlink frequency 1 (1105) to reduce power consumption (1107). That is, this corresponds to the operation scenario of FIG. 9 described above. However, the situation assumed in FIG. 11 is merely an example, and the operation of FIG. 11 may be expanded and applied.

[0217] In this case, the initial access and random access procedures of the terminal are described in order as follows. In order to support the initial access and random access procedures of the terminal, the base station transmits an SSB (1111), a PDCCH (1112) scheduling system information (SIB) (hereinafter referred to as SIB PDCCH for convenience of explanation), and a PDSCH (1113) including system information (hereinafter referred to as SIB PDSCH for convenience of explanation) through downlink frequency 2 (1115). Since the base station transmission operation at downlink frequency 1 (1105) is turned off, the base station does not transmit an SSB (1101), an SIB PDCCH (1102), and an SIB PDSCH (1103) at downlink frequency 1 (1105).

[0218] The terminal can synchronize downlink time and frequency based on the SSB (1111) and obtain a cell identifier (cell ID). 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. The MIB includes CORESET information, which is a time-frequency resource to which the SIB PDCCH is mapped. Accordingly, the terminal can monitor the SIB PDCCH that schedules the SIB PDSCH in the CORESET. The terminal can obtain the SIB by receiving the SIB PDSCH from the scheduling information of the SIB PDCCH. The SIB includes control information related to transmission and reception common to the cell, and may include, for example, random access-related control information, paging-related control information, and common control information for various physical channels. In addition, the above SIB may include frequency-related control information (1118) such as frequency domain location, bandwidth, subcarrier spacing, etc. for each of the uplink frequency and downlink frequency constituting the processing unit. Although the name of the 5G system was used to describe the embodiment of the present disclosure, the names of the SSB, SIB PDCCH, SIB PDSCH, etc. described above are only examples, and it is possible to understand them as messages that include information of the same content as described above or perform the same role.

[0219] The above SIB PDCCH may include not only scheduling information for the SIB PDSCH, but also a frequency indicator (1117) indicating an uplink frequency for transmitting uplink signals, such as a random access preamble and message 3 required for a random access procedure by the UE. For example, in the case of FIG. 11, the SIB PDCCH may include a 1-bit frequency indicator as control information, such that if it is '0', it may instruct the UE to transmit an uplink signal through uplink frequency 1 (1106), and if it is '1', it may instruct the UE to transmit an uplink signal through uplink frequency 2 (1116). The example of FIG. 11 illustrates setting the frequency indicator to '0' to instruct the UE to transmit an uplink signal through uplink frequency 1 (1106).

[0220] The frequency indicator can be generalized to represent the frequency indicator as N bits according to the number of frequencies constituting the processing unit. The bit size of the frequency indicator can be fixed to a pre-agreed value, or the base station can inform the bit size of the frequency indicator as additional control information of the MIB. Alternatively, N bits can be based on the number of frequencies to be indicated, and for example, when X is the number of frequencies to be indicated, it can be determined as ceil(log2X). The frequency indicator can be included not only in the SIB PDCCH but also in the PDCCH that schedules a paging message and the PDCCH that schedules terminal-specific data after the terminal is in a connected state. That is, the frequency indicator can be included in the PDCCH scrambled with SI-RNTI, P-RNTI, C-RNTI, etc. (or control information that schedules system information, control information that schedules paging information, or control information that schedules terminal-specific data).

[0221] The terminal should be able to minimize transmission delay by quickly changing the uplink frequency according to the instruction of the frequency indicator. Therefore, the terminal needs to have a quick frequency change operation as a basic function of the terminal. Alternatively, in order to establish a quick frequency change operation of the terminal, the frequency change operation of the terminal according to the frequency indicator may be limited to be completed within at least X time units. At this time, the time unit may be a symbol, a slot, ms, etc. For example, the X time unit may start from a specific symbol of a TTI in which control information including a frequency indicator is received on a physical downlink control channel, or from a specific symbol of a TTI in which reception acknowledgment information for the physical downlink data channel is transmitted, in case the frequency indicator is received on a physical downlink data channel. The X value may be fixed to a predetermined value or may be set by a base station.

[0222] If the base station performs repeated transmission to increase the reception reliability of the SIB PDCCH, the control information of each repeatedly transmitted SIB PDCCH is configured identically to maintain consistency. Alternatively, the base station maintains the control information of the repeatedly transmitted SIB PDCCH identically for at least a predetermined time period of Y. In this case, the time unit may be a symbol, slot, ms, etc. The Y value may be fixed to a pre-agreed value, or the base station may notify the terminal through signaling.

[0223] Meanwhile, the downlink frequency for the terminal to receive downlink signals such as message 2 and message 4 required for the random access procedure may be the same as the downlink frequency for transmitting the SSB, SIB PDCCH, and SIB PDSCH. Accordingly, the downlink frequency for receiving downlink signals required for the terminal's random access procedure can be implicitly determined by the terminal without a separate frequency instruction from the base station.

[0224] The first embodiment can be modified in various ways. For example, the N-bit frequency indicator can explicitly indicate a specific uplink frequency or can instruct the terminal to select an uplink frequency. For example, if the frequency indicator is '00', the terminal is instructed to transmit an uplink signal via uplink frequency 1, if it is '01', the terminal is instructed to transmit an uplink signal via uplink frequency 2, and if it is '10', the terminal is instructed to select between uplink frequency 1 and uplink frequency 2.

[0225] Although the first embodiment exemplifies that the frequency indicator indicates the uplink frequency, as another variation of the first embodiment, the frequency indicator may be applied commonly to the uplink frequency and the downlink frequency, or may be applied separately to the uplink frequency and the downlink frequency.

[0226] As another variation of the first embodiment, the base station can transmit the frequency indicator by including it in the SIB PDSCH.

[0227] Unlike the first embodiment, the base station may transmit the frequency indicator to the terminal via a channel other than the SIB PDCCH. Downlink signals or downlink channels that may include the frequency indicator are as follows.

[0228] - PSS or SSS: The base station may transmit the frequency indicator by configuring it with control information included in the PSS or SSS. Alternatively, the frequency indicator may be included in a physical signal for time and frequency synchronization of a terminal transmitted by the base station.

[0229] - PBCH MIB: The base station can transmit the above frequency indicator by including it as control information of the MIB included in the PBCH.

[0230] - PBCH payload: The base station can transmit the above frequency indicator as control information of the PBCH payload included in the PBCH.

[0231] - PBCH DMRS: The base station can transmit the above frequency indicator by configuring it with control information included in the DMRS for PBCH.

[0232] - SIB PDSCH: The base station may transmit the frequency indicator by including it in the SIB PDSCH. Alternatively, the base station may transmit the frequency indicator by including it in the system information.

[0233] The first embodiment described the 'processing unit' as a concept consisting of multiple frequencies, but it can be modified in various ways as follows.

[0234] - BWP: A processing unit may be composed of multiple BWPs. In this case, the above-described "frequency indicator" may be replaced with a "BWP indicator." The BWP may be understood as a portion of the frequency band of a single cell.

[0235] - Cell: A processing unit may be composed of multiple cells. In this case, the above-described 'frequency indicator' may be replaced with a 'cell indicator'.

[0236] - TRP: A processing unit may consist of multiple transmission and reception points (TRPs). Each TRP is located at a different location and performs transmission and reception operations with the terminal. In this case, the aforementioned "frequency indicator" may be replaced with a "TRP indicator."

[0237] <Example 2>

[0238] The second embodiment describes a method for switching uplink frequencies when applying a mobile communication service combining multiple frequency bands to the initial access procedure of a terminal.

[0239] Hereinafter, the operation of the second embodiment will be described with reference to FIG. 12. FIG. 12 is a diagram showing another signal transmission and reception method of a terminal and a base station according to an embodiment of the present disclosure. FIG. 12 assumes a 'processing unit' consisting of downlink frequency 1 (1201), uplink frequency 1 (1202), downlink frequency 2 (1211), and uplink frequency 2 (1212). However, the situation assumed in FIG. 12 is only an example, and the operation of FIG. 12 may be extended and applied. FIG. 12 sequentially shows an initial access procedure and a random access procedure of a terminal. For convenience of explanation, a downward arrow in FIG. 12 indicates transmission of a downlink signal, and an upward arrow indicates transmission of an uplink signal. FIG. 12 divides the operation of the terminal and the base station into 'mode 1' and 'mode 2', and it is assumed that the mode division follows the instruction of the base station.

[0240] First, according to the 'Mode 1' operation, the base station transmits SSB (1203), SIB PDCCH and SIB PDSCH (1204) to support the initial access and random access procedure of the terminal through the downlink frequency 1 (1201). The terminal can receive the signal and initiate the random access procedure. In the case of 'Mode 1', it is assumed that the base station instructs the terminal to apply the uplink frequency 1 and the downlink frequency 1 during the random access procedure. Accordingly, the terminal transmits and receives message 1 (1205), message 2 (1206), message 3 (1207), and message 4 (1208) through the uplink frequency 1 (1202) and the downlink frequency 1 (1201) during the random access procedure. In the case of 'Mode 1', the effect of reducing base station power consumption can be obtained by turning off the transmission and reception operations through downlink frequency 2 (1211) and uplink frequency 2 (1212).

[0241] According to the operation of 'Mode 2', the base station transmits SSB (1213), SIB PDCCH and SIB PDSCH (1214) to support the initial access and random access procedure of the terminal through downlink frequency 1 (1201). In the case of 'Mode 2', it is assumed that the base station instructs the terminal to apply uplink frequency 1 (1202) and downlink frequency 1 (1201) for transmission and reception of message 1 (1215) and message 2 (1216) during the random access procedure, respectively, and to apply uplink frequency 2 (1212) and downlink frequency 2 (1211) for transmission and reception of message 3 (1217) and message 4 (1218), respectively. 'Mode 2' can obtain the effect of distributing the overload of the base station processing by performing a part of the random access procedure through uplink frequency 2 and downlink frequency 2.

[0242] The base station can inform the terminal through signaling in which mode the terminal will operate. For example, the base station can inform the terminal by including a mode indicator indicating one of 'mode 1' and 'mode 2' in message 2. The terminal can continue the random access procedure according to the mode indicator obtained through message 2. Alternatively, similar to the operation for the 'frequency indicator' of the first embodiment, the base station can provide the terminal with the mode indicator by including it in at least one of the messages such as PSS, SSS, PBCH MIB, PBCH payload, PBCH DMRS, SIB PDCCH, and SIB PDSCH.

[0243] The second embodiment can be modified in various ways. FIG. 13 is a diagram illustrating another signal transmission and reception method between a terminal and a base station according to an embodiment of the present disclosure. However, the situation assumed in FIG. 13 is merely an example, and the operation of FIG. 13 can also be expanded and applied. Referring to FIG. 13, for example, in the case of 'Mode 2', the base station can instruct the terminal to apply uplink frequency 2 (1312) and downlink frequency 2 (1311) during the random access procedure. Accordingly, the terminal transmits and receives message 1 (1315), message 2 (1316), message 3 (1317), and message 4 (1318) through uplink frequency 2 (1312) and downlink frequency 2 (1311) during the random access procedure. Alternatively, the instructing mode 2 can also instruct that a specific message be transmitted and received using a specific frequency. For example, an indicator indicating mode 2 can also indicate that message 1 (1315) and message 3 (1317) are to be transmitted using uplink frequency 2 (1312). In this case, message 2 (1316) and message 4 (1318) can be received by the terminal using downlink frequency 1 (1301).

[0244] Although the names of the 5G system are used to describe the embodiments of the present disclosure, the names of the SSB, MIB, SIB PDCCH, SIB PDSCH, message 1 to 4, etc. described above are merely examples, and it is possible to understand them as messages that include information of the same content as described above or perform the same role.

[0245] <Example 3>

[0246] The third embodiment describes examples of terminal and base station procedures according to a preferred embodiment of the present invention. The terminal and base station procedures of the third embodiment can be performed in combination with at least one of the first and second embodiments.

[0247] FIG. 14 is a diagram illustrating an example of an initial connection procedure and a random access procedure of a terminal applying a 'processing unit' configured with multiple frequencies when a base station operates the same according to one embodiment of the present invention.

[0248] The terminal synchronizes downlink time and frequency using the SSB received from the base station and obtains a cell identifier (cell ID) (1401). The above SSB is merely an example, and the SSB can be replaced with a physical signal transmitted from the base station for synchronizing downlink time and frequency.

[0249] The terminal acquires the MIB, which is essential system information, and the system information (SIB) (1402). The terminal receives the PBCH using the cell ID acquired in step 1401, and acquires the MIB, which is essential system information, from the PBCH. The MIB includes CORESET information, which is a time-frequency resource to which the PDCCH is mapped. Therefore, the terminal can monitor the SIB PDCCH, which schedules the SIB PDSCH, in the CORESET. The terminal can acquire the SIB by receiving the SIB PDSCH from the scheduling information of the SIB PDCCH. The SIB includes cell-common transmission and reception-related control information, and may include, for example, random access-related control information, paging-related control information, and common control information for various physical channels. In addition, the SIB includes frequency-related control information, such as frequency domain location, bandwidth, and subcarrier spacing, for each of the uplink and downlink frequencies constituting the processing unit. The above SIB PDCCH includes not only scheduling information for the SIB PDSCH, but also a frequency indicator indicating an uplink frequency for uplink signal transmission, such as a random access preamble and message 3 required for a random access procedure by a terminal. Alternatively, as described above, the frequency indicator may be included in another message. Alternatively, the mode indicator described above may be included instead of the frequency indicator, or may be included in the same message as the frequency indicator or in another message.

[0250] The terminal determines the frequency to be applied to future transmission and reception operations from the acquired frequency-related control information and frequency indicator (1403). The terminal uses the determined frequency to perform transmission and reception operations with the base station (1404). Alternatively, the terminal may change the frequency at which messages are transmitted and received with the base station during the initial connection procedure, depending on the mode indicator.

[0251] The steps described above may be modified, omitted, changed in order, or steps not described may be added to carry out the present invention.

[0252] FIG. 15 is a diagram illustrating an example of a base station procedure that supports an initial connection procedure and a random access procedure of a terminal when the base station operates a 'processing unit' composed of multiple frequencies according to one embodiment of the present invention.

[0253] The base station transmits SSB (1501). The base station determines the frequency to be used by the terminal for transmission and reception operations (1502). The base station may consider the effect of reducing base station power consumption, etc. during the frequency determination process. The base station may perform step 1502 before step 1501.

[0254] The base station transmits system information (1503). The base station may configure frequency-related control information as system information. Additionally, it may configure a SIB PDCCH that includes a frequency indicator. Alternatively, as described above, the frequency indicator may be included in another message. Alternatively, the mode indicator described above may be included instead of the frequency indicator, or may be included in the same message as the frequency indicator or in another message.

[0255] The base station performs transmission and reception operations with the terminal using the frequency determined above (1504). Alternatively, the base station may also change the frequency at which messages are transmitted and received with the terminal during the initial connection procedure, depending on the contents of the indicated mode indicator.

[0256] The steps described above may be modified, omitted, changed in order, or steps not described may be added to carry out the present invention.

[0257] In the description of the above figures 14 and 15, after the terminal's random access procedure is completed and the terminal is switched to the RRC connected state, the base station can additionally instruct the terminal to change the frequency as needed.

[0258] FIG. 16 is a diagram illustrating an example of a terminal transceiver device in a wireless communication system according to one embodiment of the present disclosure. For convenience of explanation, devices not directly related to the present disclosure may be omitted from the illustration and description.

[0259] Referring to FIG. 16, the terminal may be configured with a transmitter (1604) including an uplink transmission processing block (1601), a multiplexer (1602), and a transmission RF block (1603), a receiver (1608) including a downlink reception processing block (1605), a demultiplexer (1606), and a reception RF block (1607), and a control unit (1609). The control unit (1609) may control each of the configuration blocks of the receiver (1608) for receiving a data channel or control channel transmitted by the base station as described above, and each of the configuration blocks of the transmitter (1604) for transmitting an uplink signal.

[0260] In the transmitter (1604) of the terminal, the uplink transmission processing block (1601) 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 (1601) can be multiplexed with another uplink signal by a multiplexer (1602), and then transmitted to the base station after signal processing in the transmission RF block (1603).

[0261] The receiving unit (1608) of the terminal demultiplexes the signal received from the base station and distributes it to each downlink receiving processing block. The downlink receiving processing block (1605) 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 receiving unit (1608) of the terminal can support the operation of the control unit (1609) by applying the output result of the downlink receiving processing block to the control unit (1609).

[0262] FIG. 17 is a block diagram showing an example of a configuration of a terminal according to one embodiment of the present disclosure.

[0263] As illustrated in FIG. 17, the terminal of the present disclosure may include a processor (1730), a transceiver (1710), and a memory (1720). 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 (1730), the transceiver (1710), and the memory (1720) may be implemented in the form of a single chip. According to one embodiment, the transceiver (1710) of FIG. 17 may include the transmitter (1604) and receiver (1608) of FIG. 16. In addition, the processor (1730) of FIG. 17 may include the control unit (1609) of FIG. 16.

[0264] According to one embodiment, the processor (1730) 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 processor may control components of the terminal to perform a transmission and reception method of the terminal based on frequency instructions from a base station. There may be one or more processors (1730), and the processors (1730) 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 (1720).

[0265] The transceiver (1710) 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 (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 a 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.

[0266] According to one embodiment, the memory (1720) can store programs and data necessary for the operation of the terminal. In addition, the memory (1720) can store control information or data included in signals transmitted and received by the terminal. 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 transmission and reception operations of the terminal according to the frequency instructions of the base station, which are the embodiments of the present disclosure described above.

[0267] FIG. 18 is a block diagram showing an example of a configuration of a base station according to one embodiment of the present disclosure.

[0268] As illustrated in FIG. 18, the base station of the present disclosure may include a processor (1430), a transceiver (1810), and a memory (1820). 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 (1830), the transceiver (1810), and the memory (1820) may be implemented in a single chip form.

[0269] The processor (1830) 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 based on a frequency indication of the base station according to the embodiments of the present disclosure. There may be one or more processors (1830), and the processors (1830) may execute a program stored in the memory (1820) to perform the method for scheduling a terminal based on a frequency indication of the base station according to the embodiments of the present disclosure described above.

[0270] The transceiver (1810) can transmit and receive signals with the terminal. The signals transmitted and received with the terminal can include control information and data. The transceiver (1810) 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 (1810) is only one embodiment, and the components of the transceiver (1810) are not limited to the RF transmitter and RF receiver. In addition, the transceiver (1810) can receive a signal through a wireless channel and output it to the processor (1830), and transmit a signal output from the processor (1830) through the wireless channel.

[0271] According to one embodiment, the memory (1820) can store programs and data necessary for the operation of the base station. In addition, the memory (1820) can store control information or data included in signals transmitted and received by the base station. The memory (1820) 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 (1820). According to one embodiment, the memory (1820) can store a program for performing a method for scheduling a terminal by a frequency indication of a base station, which are the embodiments of the present disclosure described above.

[0272] 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.

[0273] Meanwhile, the present specification and drawings have disclosed preferred embodiments of the present disclosure, and although specific terms have been used, they are used only in a general sense to easily explain the technical contents of the present disclosure and to help understand the invention, and are not intended to limit the scope of the present disclosure. It will be apparent to those skilled in the art to which the present disclosure pertains that other modified examples based on the technical idea of ​​the present disclosure are possible in addition to the embodiments disclosed herein. In addition, each of the above embodiments can be combined and operated with each other as needed. For example, the first embodiment, the second embodiment, and the third embodiment can be implemented independently, or at least one embodiment can be implemented in combination with each other.

[0274] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. In a method performed by a terminal in a communication system, A step of receiving a synchronization signal from a base station; A step of receiving system information including uplink frequency information from the base station; A step of confirming a first uplink frequency based on the above uplink frequency information; and A method characterized by comprising a step of performing a transmission and reception operation for initial access using the first uplink frequency.

2. In paragraph 1, A method characterized in that the uplink frequency information indicates the first uplink frequency for performing transmission and reception operations for the initial connection, or includes at least one of configuration information for a physical channel and a physical signal related to the first uplink frequency.

3. In paragraph 1, A method characterized in that the above uplink frequency information is included in essential system information, included in scheduling information for scheduling the system information, or included in the system information.

4. In paragraph 1, The transmission and reception operations for the above initial connection include random access operations, When a mode indicator is received, the random access operation is performed using the second uplink frequency, A method characterized in that the above mode indicator is included in the above system information or in message 2 of the random access operation.

5. In a method performed by a base station in a communication system, Step of transmitting a synchronization signal; A step of identifying a first uplink frequency for performing transmission and reception operations for initial access; A step of transmitting system information including uplink frequency information related to the first uplink frequency to a terminal; A method characterized by comprising a step of performing a transmission and reception operation for initial access using the terminal and the first uplink frequency.

6. In paragraph 5, A method characterized in that the uplink frequency information indicates the first uplink frequency for performing transmission and reception operations for the initial connection, or includes at least one of configuration information for a physical channel and a physical signal related to the first uplink frequency.

7. In paragraph 5, A method characterized in that the above uplink frequency information is included in essential system information, included in scheduling information for scheduling the system information, or included in the system information.

8. In paragraph 5, The transmission and reception operations for the above initial connection include random access operations, When a mode indicator is received, the random access operation is performed using the second uplink frequency, A method characterized in that the above mode indicator is included in the above system information or in message 2 of the random access operation.

9. At the terminal of the communication system, At least one transceiver; At least one processor communicatively connected to at least one transceiver; and Communicably connected to at least one processor, and executable individually or in any combination of said at least one processor, such that said terminal: Receive a synchronization signal from the base station, Receive system information including uplink frequency information from the base station, Check the first uplink frequency based on the above uplink frequency information, and A terminal characterized by comprising a memory storing a command to perform a transmission and reception operation for initial access using the first uplink frequency.

10. In paragraph 9, A terminal characterized in that the uplink frequency information indicates the first uplink frequency for performing transmission and reception operations for the initial connection, or includes at least one of configuration information for a physical channel and a physical signal related to the first uplink frequency.

11. In paragraph 9, A terminal characterized in that the above uplink frequency information is included in essential system information, included in scheduling information that schedules the system information, or included in the system information.

12. In paragraph 11, The transmission and reception operations for the above initial connection include random access operations, When a mode indicator is received, the random access operation is performed using the second uplink frequency, A terminal characterized in that the above mode indicator is included in the above system information or in message 2 of the random access operation.

13. In the base station of the communication system, At least one transceiver; At least one processor communicatively connected to at least one transceiver; and Communicably connected to at least one processor, and executable individually or in any combination of said at least one processor, such that said base station: Transmit a synchronization signal, Check the first uplink frequency for performing transmission and reception operations for initial access, Transmit system information including uplink frequency information related to the first uplink frequency to the terminal, A base station characterized by comprising: a memory storing a command for performing a transmission and reception operation for initial access using the terminal and the first uplink frequency; 14. In paragraph 13, A base station characterized in that the uplink frequency information indicates the first uplink frequency for performing transmission and reception operations for the initial connection, or includes at least one of configuration information for a physical channel and a physical signal related to the first uplink frequency.

15. In paragraph 13, The above uplink frequency information is included in essential system information, included in scheduling information that schedules the above system information, included in the above system information, or A base station characterized in that the transmission and reception operation for the initial connection includes a random access operation, and when a mode indicator is received, the random access operation is performed using a second uplink frequency, and the mode indicator is included in the system information or included in message 2 of the random access operation.

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