Initial access method and device based on discovery signal in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates, and relates to a method comprising the steps of: transmitting a discovery signal to a terminal; receiving a request related to a synchronization signal from the terminal; transmitting an on-demand SSB to the terminal; and performing a random access procedure, wherein the discovery signal is transmitted on the basis of a block for transmitting the discovery signal from an antenna of a base station, and the block is not used for transmitting signals other than the discovery signal.

Description

Method and device for initial access based on discovery signal of a wireless communication system

[0001] The present disclosure relates to a communication method of a wireless communication system, and more specifically to a method and apparatus for defining efficient frequency usage 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 frequency bands below 6 GHz ('Sub 6 GHz'), such as 3.5 gigahertz (3.5 GHz), but also in ultra-high frequency bands known as millimeter wave (mmWave), such as 28 GHz and 39 GHz ('Above 6 GHz'). In addition, for 6G mobile communication technology, which is referred to as a system beyond 5G, measures are being considered to achieve even faster transmission speeds and even lower ultra-low latency compared to 5G mobile communication technology.

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

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

[0005] In addition, standardization was also carried out for technologies such as the Industrial Internet of Things (IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) which provides nodes to expand network service areas by integrating wireless backhaul links and access links, Mobility Enhancement including Conditional Handover and Dual Active Protocol Stack (DAPS) Handover, and 2-step RACH for NR which simplifies random access procedures.

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

[0007] With the commercialization of such 5G mobile communication systems, connected devices, which are increasing explosively, will be connected to communication networks. Accordingly, it is expected that there will be a need to enhance the functionality and performance of 5G mobile communication systems and to integrate the operation of connected devices. To this end, new research is planned to be conducted on 5G performance improvement and complexity reduction, support for AI services, support for metaverse services, and drone communication using eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0008] In addition, the advancement of these 5G mobile communication systems can serve as a foundation for the development of new waveforms for ensuring coverage of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas, metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surface (RIS) technology, as well as Full Duplex technology for improving frequency efficiency and system networks of 6G mobile communication technology, AI-based communication technology that realizes system optimization by utilizing satellites and AI from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology that realizes services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources.

[0009] The disclosed embodiment aims to provide an apparatus and method capable of effectively providing mobile communication services. Specifically, it provides a procedure for energy saving between a base station and a terminal, and a measurement operation of the terminal.

[0010] The technical problems to be solved in the disclosed embodiments are not limited to those mentioned above, and other unmentioned technical problems may be considered by those skilled 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 base station of a wireless communication system comprises: transmitting a discovery signal to a terminal; receiving a request related to a synchronization signal from the terminal; transmitting an on-demand synchronization signal block (SSB) to the terminal; and performing a random access procedure, wherein the discovery signal is transmitted based on a block for transmitting the discovery signal from the antenna of the base station, and the block is not used for transmitting signals other than the discovery signal.

[0012] Additionally, the block includes one or more antenna panels for the discovery signal, and the one or more antenna panels are characterized in that the base station is not used for transmitting signals other than the discovery signal.

[0013] Additionally, the block includes a set of antenna subarrays for the discovery signal of the antenna panel, and the set of antenna subarrays includes one or more antenna subarrays, and the one or more antenna subarrays are characterized in that the base station is not used for transmitting signals other than the discovery signal.

[0014] In addition, the on-demand SSB is broadcast based on at least one of a period longer than the SSB, a fixed number of times, or a fixed time interval, and the discovery signal is characterized by having its priority determined based on the SSB and RSRP (reference signal received power) information or time information when the terminal receives the discovery signal and the SSB.

[0015] According to one embodiment of the present disclosure, a method performed by a terminal of a wireless communication system comprises: receiving a discovery signal from a base station; transmitting a request related to a synchronization signal to the base station; receiving an on-demand synchronization signal block (SSB) from the base station; and performing a random access procedure, wherein the discovery signal is transmitted based on a block for transmitting the discovery signal from the antenna of the base station, and the block is not used for transmitting signals other than the discovery signal.

[0016] According to one embodiment of the present disclosure, a base station of a wireless communication system comprises: a transceiver; and a control unit connected to the transceiver, which transmits a discovery signal to a terminal, receives a request related to a synchronization signal from the terminal, transmits an on-demand synchronization signal block (SSB) to the terminal, and performs a random access procedure, wherein the discovery signal is transmitted based on a block for transmitting the discovery signal from the antenna of the base station, and the block is not used for transmitting signals other than the discovery signal.

[0017] According to one embodiment of the present disclosure, a terminal of a wireless communication system comprises: a transceiver; and a control unit connected to the transceiver, receiving a discovery signal from a base station, transmitting a request related to a synchronization signal to the base station, receiving an on-demand synchronization signal block (SSB) from the base station, and performing a random access procedure, wherein the discovery signal is transmitted based on a block for transmitting the discovery signal from the antenna of the base station, and the block is not used for transmitting signals other than the discovery signal.

[0018] An embodiment of the present disclosure provides a transceiver device and method for a terminal and a base station that improves frequency usage efficiency in a mobile communication system. Specifically, according to at least one embodiment of the present disclosure, the base station and the terminal can effectively perform an initial connection procedure for energy saving between the base station and the terminal.

[0019] The effects obtainable from the disclosed embodiments are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by a person skilled in the art based on the following detailed description.

[0020] FIG. 1 is a diagram showing the basic structure of the time-frequency resource domain of a 5G system according to one embodiment of the present disclosure.

[0021] FIG. 2 is a diagram illustrating a random access procedure according to one embodiment of the present disclosure.

[0022] FIG. 3 is a diagram illustrating a procedure in which a terminal reports terminal capability (UE capability) information to a base station according to one embodiment of the present disclosure.

[0023] FIG. 4 is a drawing showing an example of a bandwidth portion setting according to an embodiment of the present disclosure.

[0024] FIG. 5 is a diagram showing the interrelationship between frequency bands and coverage according to one embodiment of the present disclosure.

[0025] FIG. 6 is a diagram showing an example of a base station energy saving method according to one embodiment of the present disclosure.

[0026] FIG. 7 is a drawing showing an example of a base station energy saving method according to one embodiment of the present disclosure.

[0027] FIG. 8 is a drawing showing an example of a base station energy saving method according to one embodiment of the present disclosure.

[0028] FIG. 9 is a drawing showing an example of a base station energy saving method according to one embodiment of the present disclosure.

[0029] FIG. 10 is a diagram illustrating an initial connection procedure of a terminal utilizing a discovery signal according to one embodiment of the present disclosure.

[0030] FIG. 11 is a drawing showing an example of an antenna configuration of a base station according to one embodiment of the present disclosure.

[0031] FIG. 12 is a drawing showing an example of an antenna configuration of a base station according to one embodiment of the present disclosure.

[0032] FIG. 13 is a drawing showing an example of an antenna configuration of a base station according to one embodiment of the present disclosure.

[0033] FIG. 14 is a diagram showing an example of an initial connection procedure of a terminal according to one embodiment of the present disclosure.

[0034] FIG. 15 is a diagram showing an example of a base station procedure for supporting a terminal initial connection procedure according to one embodiment of the present disclosure.

[0035] FIG. 16 is a diagram showing an example of a mobile communication network scenario according to one embodiment of the present disclosure.

[0036] FIG. 17 is a diagram showing an example of an initial connection procedure of a terminal according to one embodiment of the present disclosure.

[0037] FIG. 18 is a drawing showing a terminal transceiver device according to one embodiment of the present disclosure.

[0038] FIG. 19 is a block diagram illustrating the structure of a terminal according to one embodiment of the present disclosure.

[0039] FIG. 20 is a block diagram illustrating the structure of a base station according to one embodiment of the present disclosure.

[0040] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, in describing the present disclosure, if it is determined that a detailed description of related known functions or configurations might unnecessarily obscure the essence of the present disclosure, such detailed description will be omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the content throughout this specification.

[0041] The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. The embodiments provided are merely to make the present disclosure complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0042] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0043] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to their corresponding functions.

[0044] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Accordingly, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and '~parts' may be implemented to utilize one or more CPUs within the device or secure multimedia card. Also, in the embodiment, the '~part' may include one or more processors.

[0045] In the present disclosure, each of the phrases such as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B or C,” “at least one of A, B and C,” and “at least one of A, B, or C” may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof. Terms such as “first,” “second,” or “first” or “second” may be used simply to distinguish a corresponding component from another corresponding component and do not limit the components in any other aspect (e.g., importance or order).

[0046] In describing the present disclosure below, if it is determined that a detailed description of related known functions or configurations could unnecessarily obscure the essence of the present disclosure, such detailed description will be omitted. Embodiments of the present disclosure will be described below with reference to the attached drawings.

[0047] 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 examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0048] In the following description, the terms "physical channel" and "physical signal" may be used interchangeably with "data" or "control signal." For example, PDSCH (physical downlink shared channel) is a term referring to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in this disclosure, the expression "transmits a physical channel" may be interpreted as equivalent to the expression "transmits data or a signal through a physical channel."

[0049] In the present disclosure, upper layer signaling refers to a signal transmission method transmitted from a base station to a terminal using a physical layer downlink data channel, or from a terminal to a base station using a physical layer uplink data channel. Upper layer signaling can be understood as a Master Information Block (MIB), System Information Block (SIB), Radio Resource Control (RRC) signaling, or Media Access Control (MAC) control element (CE).

[0050] For the convenience of the following description, the present disclosure uses terms and names defined in the 3GPP NR (New Radio: 5th generation mobile communication standard) specifications. However, the present disclosure is not limited to the above terms and names and may be applied equally to systems conforming to other standards. For example, regarding 6G systems, which are still in the early stages of standardization discussion, terms and names defined in 5G systems may be generalized and used to describe the operation of 6G systems unless otherwise specifically noted.

[0051] Hereinafter, the base station is an entity that performs resource allocation for terminals and may be at least one of a gNodeB, gNB, eNodeB, eNB, NodeB, BS (Base Station), wireless access unit, base station controller, or a node on a network. The terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, IoT device, sensor, or multimedia system capable of performing communication functions. Of course, it is not limited to the examples described.

[0052] While existing mobile communication systems focused on conventional voice / data communication, 5G systems aim to satisfy various services and requirements, such as enhanced Mobile BroadBand (eMBB) services to improve existing voice / data communication, Ultra-Reliable and Low Latency Communication (URLLC) services, and massive Machine Type Communication (MTC) services to support mass communication of the Internet of Things.

[0053] While the transmission bandwidth per carrier 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 20 MHz, 5G systems aim to provide ultra-high-speed data services reaching several Gbps by utilizing significantly wider ultra-wide bandwidths. Accordingly, 5G systems are considering ultra-high frequency bands ranging from several GHz to a maximum of 100 GHz as operating frequencies, where securing ultra-wide bandwidth frequencies is relatively easy. Additionally, it is possible to secure wide bandwidth frequencies for 5G systems through frequency reallocation or allocation from frequency bands ranging from hundreds of MHz to several GHz used by existing mobile communication systems.

[0054] Radio waves in the ultra-high frequency band have wavelengths of several millimeters and are also called millimeter waves (mmWave). However, in the ultra-high frequency band, path loss of radio waves increases in proportion to the frequency band, so the coverage of mobile communication systems can be reduced.

[0055] To overcome the disadvantage of reduced coverage in the ultra-high frequency band, beamforming technology can be applied. This technology uses multiple antennas to concentrate radio wave radiated energy toward a specific target point, thereby increasing the reach of the radio waves. In other words, a signal to which beamforming technology is applied has a relatively narrower beam width, and as radiated energy is concentrated within this narrowed beam width, the reach of the radio waves increases. Beamforming technology can be applied to both the transmitting and receiving ends. In addition to the effect of increasing coverage, beamforming technology also has the effect of reducing interference in areas outside the beamforming direction. For beamforming technology to operate properly, accurate measurement and feedback methods for the transmit and receive beams are required. Beamforming technology can be applied to control channels or data channels that correspond one-to-one between a specific terminal and a base station. Furthermore, beamforming technology can be applied to control channels and data channels used to transmit common signals—such as synchronization signals, physical broadcast channels (PBCH), and system information—that a base station transmits to multiple terminals within the system, in order to increase coverage. When applying beamforming technology to a common signal, beam sweeping technology, which changes the beam direction to transmit the signal, is additionally applied to ensure that the common signal reaches terminals located at any position within the cell.

[0056] Another requirement for 5G systems is ultra-low latency services, where the transmission delay between the transmitter and receiver is approximately 1ms. As a measure to reduce transmission delay, it is necessary to design a frame structure based on a short TTI (Transmission Time Interval) that is shorter than that of LTE and LTE-A. TTI is the basic time unit for performing scheduling, and the TTI of existing LTE and LTE-A systems is 1ms, which corresponds to the length of one subframe. For example, in 5G systems, short TTIs such as 0.5ms, 0.25ms, and 0.125ms are possible, which are shorter than those of existing LTE and LTE-A systems, to satisfy the requirements for ultra-low latency services.

[0057] 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. That is, FIG. 1 is a diagram showing the basic structure of a time-frequency resource domain, which is a wireless resource domain where data or control channels of a 5G system are transmitted.

[0058] Referring to FIG. 1, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit of a 5G system in the time domain is an OFDM (Orthogonal Frequency Division Multiplexing) symbol, A number of symbols (102) are combined to form a slot (106), and A number of slots can be combined to form a single subframe (105). The length of a single subframe (105) is 1.0 ms, and 10 subframes can be combined to form a single frame (114), and the length of the frame (114) is 10 ms. 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 BWIt can be composed of several subcarriers (104).

[0059] In the time-frequency domain, the basic unit of a resource 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 in the frequency domain. It can be defined as a series of consecutive subcarriers (110). In a 5G system = 12, and the data rate can increase in proportion to the number of RBs scheduled to the terminal.

[0060] In a 5G system, base stations map data in RB units and can generally perform scheduling on RBs that constitute a slot for a given terminal. That is, in a 5G system, the basic time unit for which scheduling is performed is a slot, and the basic frequency unit for which scheduling is performed may be an RB.

[0061] OFDM symbol count It is determined by the length of the cyclic prefix (CP) added to each symbol to prevent interference between symbols; for example, if a normal CP is applied = 14, if Extended CP is applied = 12. Extended CP is applied to systems with relatively longer transmission distances than standard CP, enabling the maintenance of orthogonality between symbols. In the case of standard CP, the ratio of CP length to symbol length is maintained at a constant value, allowing the overhead caused by CP to remain constant regardless of the subcarrier spacing. That is, if the subcarrier spacing is small, the symbol length increases, and consequently, the CP length can also increase. Conversely, if the subcarrier spacing is large, the symbol length decreases, and consequently, the CP length can be reduced. The symbol length and CP length can be inversely proportional to the subcarrier spacing.

[0062] In 5G systems, various frame structures can be supported by adjusting the subcarrier spacing to satisfy various services and requirements. For example, the characteristics according to the subcarrier spacing are as follows.

[0063] From the perspective of the operating frequency band, a larger subcarrier spacing is advantageous for recovering phase noise in the high-frequency band.

[0064] - From the perspective of transmission time, a large subcarrier spacing shortens the symbol length in the time domain, and consequently shortens the slot length, which is advantageous for supporting ultra-low latency services such as URLLC.

[0065] - From the perspective of cell size, a longer CP length allows for the support of larger cells, so a smaller subcarrier spacing allows for the support of relatively larger cells. A cell is a concept in mobile communication that refers to the area covered by a single base station.

[0066] Subcarrier spacing and CP length are essential information for OFDM transmission and reception, and smooth transmission and reception are possible only when the base station and the terminal recognize the subcarrier spacing and CP length as common values. shows examples of the relationships between subcarrier spacing configuration (μ), subcarrier spacing (Δf), and CP length supported by 5G systems.

[0067]

[0068] shows the number of symbols per slot for each subcarrier spacing setting (μ) in the case of the general type CP ( ), number of slots per frame( ), and number of slots per subframe( Represents an example of ).

[0069]

[0070] shows the number of symbols per slot for each subcarrier spacing setting (μ) in the case of extended CP ( ), number of slots per frame( ), number of slots per subframe( Represents an example of ).

[0071]

[0072] A 5G system can satisfy various user requirements through coexistence or dual-mode operation with existing LTE or / and LTE-A (hereinafter LTE / LTE-A) systems. For example, existing LTE / LTE-A systems can provide stable system operation to terminals, while 5G systems can perform the role of providing enhanced services to terminals. Therefore, the frame structure of a 5G system needs to include at least the frame structure of LTE / LTE-A or a set of essential parameters (subcarrier spacing = 15 kHz).

[0073] For example, when comparing a frame structure with a subcarrier spacing setting μ=0 (hereinafter frame structure A) and a frame structure with a subcarrier spacing setting μ=1 (hereinafter frame structure B), compared to frame structure A, frame structure B shows that the subcarrier spacing and RB size are doubled, while the slot length and symbol length are doubled. In the case of frame structure B, two slots can form one subframe, and 20 subframes can form one frame.

[0074] By generalizing the frame structure of a 5G system, high scalability can be provided by ensuring that the essential parameter sets, such as subcarrier spacing, CP length, and slot length, have an integer multiple relationship with each other for each frame structure. Additionally, a subframe of fixed length of 1ms can be defined to represent a reference time unit independent of the frame structure.

[0075] The frame structure of a 5G system can be applied to various scenarios. From the perspective of cell size, since a longer CP length enables support for larger cells, Frame Structure A can support relatively larger cells compared to Frame Structure B. From the perspective of operating frequency band, since a larger subcarrier spacing is advantageous for recovering phase noise in the high-frequency band, Frame Structure B can support relatively higher operating frequencies compared to Frame Structure A. From the perspective of service, since a shorter slot length—the basic time unit of scheduling—is advantageous for supporting ultra-low latency services such as URLLC, Frame Structure B may be relatively more suitable for URLLC services compared to Frame Structure A.

[0076] In a manner similar to the coexistence of 5G and LTE / LTE-A mentioned above, it may be necessary to design a system for the coexistence of 6G, which will arrive with the evolution of future communication systems, and existing systems such as 5G or LTE / LTE-A.

[0077] In the following description of the present disclosure, an uplink (UL) refers to a wireless link through which a terminal transmits data or control signals to a base station, and a downlink (DL) may refer to a wireless link through which a base station transmits data or control signals to a terminal.

[0078] In the initial access phase, when the terminal first connects to the system, the terminal can synchronize downlink time and frequency from the synchronization signal transmitted by the base station through cell search and obtain a cell ID. Then, the terminal can receive a physical broadcast channel (PBCH) using the obtained cell ID and obtain a master information block (MIB), which is essential system information, from the PBCH. The MIB may include at least one of the following information.

[0079]

[0080] For example, the above essential system information may include at least one of the following: information regarding the location of a synchronization signal received by the terminal in the time domain and / or frequency domain; control information for the terminal to receive at least one of 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 regarding whether the cell is connectable; and information regarding the SCS of the cell. The above essential system information may be referred to as system information.

[0081] Additionally, the terminal can receive system information transmitted by the base station to obtain cell-common transmission and reception control information. Cell-common transmission and reception control information may include random access control information, paging control information, and at least one of various physical channels and signals (at least one of channels and signals, 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 status information, a physical signal for obtaining downlink channel status 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, for example, as SIB1 or RMSI (remaining minimum system information).

[0082] The synchronization signal is a signal that serves as a reference for cell search, and a subcarrier spacing may be applied for each frequency band to suit channel environments such as phase noise. In the case of data channels or control channels, as described above, the subcarrier spacing may be applied differently depending on the service type to support various services. In a 5G system, a combination consisting of PSS (primary synchronization signal), SSS (secondary synchronization signal), and PBCH (Physical broadcast channel) can be referred to as an SS / PBCH block or SSB. For example, an SSB may consist of N1 PSS symbols, N2 SSS symbols, and N3 PBCH symbols.

[0083] In addition to the above initial connection procedure, the terminal may also receive an SSB to determine whether the radio link quality of the current cell is maintained at a certain level or higher. Additionally, in the procedure where the terminal performs a handover from the current cell to an adjacent cell, the terminal may receive an SSB from an adjacent cell to determine the radio link quality of the adjacent cell and to obtain time / frequency synchronization of the adjacent cell.

[0084] After the terminal obtains MIB and system information from the base station through the initial access procedure, the terminal may perform a random access procedure to transition the link with the base station to a connected state (connected state or RRC_CONNECTED state). Upon completion of the random access procedure, the terminal transitions to a connected state, enabling one-to-one communication between the base station and the terminal. The random access procedure will be described in detail below with reference to FIG. 2.

[0085] FIG. 2 is a diagram illustrating a random access procedure according to one embodiment of the present disclosure.

[0086] Referring to FIG. 2, as a first step (210) of the random access procedure, the terminal can transmit a random access preamble to the base station. The random access preamble, which is the initial 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 from a set of random access preambles given in advance by system information. The initial transmission power of the random access preamble can be determined according to the path loss between the base station and the terminal measured by the terminal. Additionally, 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.

[0087] In the second step (220), the base station may transmit a message to the terminal containing an uplink transmission timing control command based on the transmission delay value measured from the random access preamble received in the first step (210). The terminal may receive control information for scheduling the message over the downlink control channel and receive the message over the 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. Additionally, the base station may transmit the message by including, as scheduling information, uplink resources to be used by the terminal to transmit a response message (message 3) to message 2 and power control commands to be applied to the response message. The scheduling information may include control information regarding the terminal's uplink transmission beam. Additionally, 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 information described above may be included in message 2.

[0088] 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 terminal may perform the first step (210) again. If the first step (210) is performed again, the terminal may increase the probability of receiving the random access preamble at the base station by increasing the transmission power of the random access preamble by a predetermined step (power ramping).

[0089] In the third step (230), the terminal can transmit uplink data (message 3) including its terminal ID to the base station via the uplink data channel (physical uplink shared channel, PUSCH) based on 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). 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 refer to the first uplink data signal transmitted by the terminal to the base station after the transmission of the random access preamble. For example, the message 3 may include an upper layer message for the terminal to connect to the network.

[0090] In step 4 (240), if the base station determines that the terminal has performed random access without collision with other terminals, it may transmit data (message 4) containing 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 may determine that the random access was successful. Then, the terminal may transmit HARQ-ACK information indicating successful reception of message 4 to the base station through the Physical Uplink Control Channel (PUCCH).

[0091] If the data transmitted by the terminal in the third step (230) collides with the data of another terminal and the base station fails to receive the data signal from the terminal, the base station may not transmit any further data to the terminal. Accordingly, if the terminal fails to receive the data transmitted from the base station in the fourth step (240) within a certain period of time, it is determined that the random access procedure has failed, and the process may be restarted from the first step (210).

[0092] 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 through messages other than the four-step message described above. For example, the terminal may transmit one or more messages containing at least one of the information of message 1 and message 3 to the base station simultaneously or sequentially, and the base station may transmit one or more messages containing at least one of the information of message 2 and message 4 to the terminal simultaneously or sequentially.

[0093] Upon successful completion of the random access procedure, the terminal transitions to a connected state, enabling one-to-one communication between the base station and the terminal. The base station can receive UE capability information from the terminal in the connected state. The base station can adjust scheduling by referring to the UE capability information of the terminal. Through the UE capability information, the terminal can inform the base station whether it supports certain functions and / or the maximum allowable value of the functions supported by the terminal. Therefore, the UE capability information reported by each terminal to the base station may be different for each terminal.

[0094] For example, the terminal may report UE capability information to the base station as UE capability information, including at least a portion of the following control information.

[0095] - Control information related to frequency bands supported by the terminal

[0096] - Control information related to channel bandwidth supported by the terminal

[0097] - Control information regarding the maximum modulation scheme supported by the terminal

[0098] - Control information regarding the maximum number of beams supported by the terminal

[0099] - Control information regarding the maximum number of layers supported by the terminal

[0100] - Control information related to CSI reporting supported by the terminal

[0101] - Control information on whether the terminal supports frequency hopping

[0102] - Bandwidth-related control information when Carrier Aggregation (CA) is supported

[0103] - Control information on whether cross-carrier scheduling is supported when carrier bundling is supported

[0104] FIG. 3 is a diagram illustrating a procedure in which a terminal reports terminal capability (UE capability) information to a base station according to one embodiment of the present disclosure.

[0105] Referring to FIG. 3, in step 310, the base station (302) can send a UE capability information request message to the terminal (301). In response to the base station's UE capability information request, the terminal can send UE capability information to the base station in step 320.

[0106] Next, the Bandwidth Part (BWP) setting in the 5G communication system will be explained in detail with reference to the drawing.

[0107] Figure 4 is a diagram illustrating an example of a bandwidth portion setting in a 5G communication system.

[0108] FIG. 4 shows an example in which the terminal bandwidth (UE bandwidth) (400) is configured into two bandwidth portions, namely bandwidth portion #1 (BWP#1) (401) and bandwidth portion #2 (BWP#2) (402). The base station may configure one or more bandwidth portions for the terminal and may configure the information in below for each bandwidth portion.

[0109]

[0110] Of course, the above examples are not limited, and various parameters related to bandwidth portions may be configured for the terminal in addition to the above configuration information. The above information may be transmitted by the base station to the terminal via higher-layer signaling, for example, Radio Resource Control (RRC) signaling. At least one of the configured bandwidth portions may be activated. Whether a configured bandwidth portion is activated may be transmitted semi-statically from the base station to the terminal via RRC signaling or dynamically via Downlink Control Information (DCI).

[0111] According to some embodiments, prior to the RRC connection, the terminal may receive an Initial Bandwidth Part (Initial BWP) for initial connection from the base station via a Master Information Block (MIB). More specifically, during the initial connection phase, the terminal may receive configuration information regarding a Control Resource Set (CORESET) and a Search Space via the MIB, through which a Physical Downlink Control Channel (PDCCH) can be transmitted to receive System Information Blocks (System Information Block) required for initial connection. The Control Resource Set and Search Space configured via the MIB may each be considered as Identity (ID) 0 (CORESET 0, Search Space 0). The base station may notify the terminal via the MIB of configuration information, such as frequency allocation information, time allocation information, and subcarrier interval settings, for Control Resource Set #0. Additionally, the base station may notify the terminal via the MIB of configuration information regarding the monitoring period and monitoring occasion for Control Resource Set #0, i.e., configuration information for Search Space #0. The terminal may consider the frequency region set as control region #0 obtained from the MIB as the initial bandwidth portion for initial access. In this case, the identifier (ID) of the initial bandwidth portion may be considered as 0.

[0112] The settings for the bandwidth portion supported by the above 5G can be used for various purposes.

[0113] According to one embodiment, if the bandwidth supported by the terminal is smaller than the system bandwidth, this can be supported through the bandwidth portion setting. For example, by setting the frequency position of the bandwidth portion (setting information 2) to the terminal, the terminal can transmit and receive data at a specific frequency position within the system bandwidth.

[0114] In addition, according to some embodiments, a base station may set multiple bandwidth portions for a terminal for the purpose of supporting different subcarrier spacing settings. For example, to support data transmission and reception using both a 15 kHz subcarrier spacing and a 30 kHz subcarrier spacing for a terminal, two bandwidth portions may be set to subcarrier spacings of 15 kHz and 30 kHz, respectively. Different bandwidth portions may be frequency division multiplexed (FDM), and when data transmission and reception is to be performed at a specific subcarrier spacing, the bandwidth portion set to that subcarrier spacing may be activated.

[0115] In addition, according to some embodiments, a base station may set bandwidth portions with different bandwidth sizes for the purpose of reducing the power consumption of the terminal. For example, if the terminal supports a very large bandwidth, such as 100 MHz, and always transmits and receives data using that bandwidth, very large power consumption may occur. In particular, in a situation where there is no traffic, monitoring an unnecessary downlink control channel using a large bandwidth of 100 MHz may be very inefficient in terms of power consumption. To reduce the power consumption of the terminal, the base station may set a bandwidth portion with a relatively small bandwidth, such as 20 MHz, for the terminal. In a situation where there is no traffic, the terminal can perform monitoring operations in the 20 MHz bandwidth portion, and when data is generated, it can transmit and receive data using the 100 MHz bandwidth portion according to the instructions of the base station.

[0116] In the method for configuring the above bandwidth portion, terminals prior to RRC connection (Connected) can receive configuration information for the Initial Bandwidth Part (Initial BWP) through the MIB during the initial connection phase. More specifically, the terminal can receive a configuration of a control area (i.e., CORESET) for a downlink control channel through which a DCI scheduling a System Information Block (SIB) can be transmitted from the MIB of the Physical Broadcast Channel (PBCH). The bandwidth of the control area configured based on the MIB can be considered as the Initial Bandwidth Part, and through the configured Initial Bandwidth Part, the terminal can receive the Physical Downlink Shared Channel (PDSCH) through which the SIB is transmitted. In addition to the purpose of receiving the SIB, the Initial Bandwidth Part may also be utilized for paging or random access.

[0117] Next, downlink control information (DCI) in 5G systems will be explained in detail.

[0118] In a 5G system, scheduling information for uplink data (or physical uplink shared channel (PUSCH)) or scheduling information for downlink data (or physical downlink shared channel (PDSCH)) can be transmitted from a base station to a terminal via DCI. The terminal can monitor the fallback DCI format and the non-fallback DCI format for PUSCH or PDSCH. The fallback DCI format may consist of fixed fields predefined between the base station and the terminal, and the non-fallback DCI format may include configurable fields.

[0119] DCI can be transmitted via the physical downlink control channel (PDCCH) after undergoing channel coding and modulation processes. A cyclic redundancy check (CRC) is attached to the DCI message payload, and the CRC can be scrambled with the terminal's identity identifier (e.g., radio network temporary identifier, RNTI). Different RNTIs may be used depending on the purpose of the DCI message, such as UE-specific data transmission, power control commands, or random access responses. In other words, the RNTI may not be transmitted explicitly but may be included in the CRC calculation process. Upon receiving a DCI message transmitted via the PDCCH, the terminal checks the CRC using the assigned RNTI; if the CRC check result is correct, the terminal knows that the message has been transmitted to it.

[0120] For example, a DCI scheduling a PDSCH for system information can be scrambled to SI-RNTI. For example, a DCI scheduling a PDSCH for a RAR message can be scrambled to RA-RNTI. For example, a DCI scheduling a PDSCH for a paging message can be scrambled to P-RNTI. A DCI notifying a SFI (slot format indicator) can be scrambled to SFI-RNTI. A DCI notifying a TPC (transmit power control) can be scrambled to TPC-RNTI. For example, a DCI scheduling a terminal-specific PDSCH or PUSCH can be scrambled to C-RNTI (cell RNTI).

[0121] A base station may operate by applying a predetermined DCI format to a terminal to be scheduled, depending on whether the DCI is for scheduling information for downlink data (downlink assignment), scheduling information for uplink data (uplink grant), and / or for DCI used for purposes other than data scheduling, such as power control.

[0122] The base station can transmit downlink data to the terminal via the Physical Downlink Shared Channel (PDSCH), which is a physical channel for downlink data transmission. Scheduling information, such as specific mapping locations in the time and frequency domains of the PDSCH, modulation schemes, HARQ-related control information, and power control information, can be provided by the base station to the terminal through the DCI related to downlink data scheduling information among the DCIs transmitted via the PDSCH.

[0123] The terminal can transmit uplink data to the base station via the PUSCH (physical uplink shared channel), which is a physical channel for uplink data transmission. Scheduling information, such as specific mapping locations in the time and frequency domains of the PUSCH, modulation schemes, HARQ-related control information, and power control information, can be provided by the base station to the terminal through the DCI related to uplink data scheduling information among the DCIs transmitted via the PDCCH.

[0124] The time-frequency resource to which the PDCCH is mapped is called a control resource set (CORESET). In the frequency domain, a CORESET can be configured on all or part of the frequency resources within the bandwidth supported by the terminal. In the time domain, it can be configured with one or more OFDM symbols, which can be defined as the CORESET duration. A base station can configure one or more CORESETs for the terminal through higher-layer signaling (e.g., System Information, Master Information Block (MIB), Radio Resource Control (RRC) signaling). Configuring a CORESET for a 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 provided by the base station to the terminal to configure a CORESET may include at least some of the information included in .

[0125]

[0126] CORESET in the frequency domain It can be composed of RBs, and in the time domain It can be composed of ∈{1,2,3} symbols. A PDCCH can be composed of one or more CCEs (Control Channel Elements). One CCE can be composed of six REGs (Resource Element Groups), and a REG can be defined as one RB during one OFDM symbol. Within a CORESET, REGs can be indexed in time-first order starting with REG index 0, beginning with the first OFDM symbol of the CORESET, the lowest RB.

[0127] Interleaved and non-interleaved methods may be supported as transmission methods for PDCCH. The base station may configure the terminal to perform interleaved or non-interleaved transmission for each CORESET through upper-layer signaling. Interleaving may be performed on a REG bundle basis. A REG bundle may be defined as a set of one or more REGs. Based on the interleaved or non-interleaved transmission configuration received from the base station, the terminal may determine the CCE-to-REG mapping method in the corresponding CORESET in the manner shown in below.

[0128]

[0129] The base station can inform the terminal of configuration information, such as which symbol the PDCCH is mapped to within the slot and the transmission period, through signaling.

[0130] The search space of a PDCCH is described as follows. The number of CCEs required to transmit a 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, one downlink control channel can be transmitted through L CCEs. The terminal performs blind decoding to detect signals without knowing information about the downlink control channel; to this end, 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 terminal must attempt to decode at a given aggregation level. Since there are various aggregation levels that form a group of 1, 2, 4, 8, or 16 CCEs, the terminal may have multiple search spaces. A Search Space Set can be defined as a set of search spaces at all established aggregation levels.

[0131] Search spaces can be classified into Common Search Spaces (CSS) and UE-specific Search Spaces (USS). A certain group of terminals or all terminals may monitor the Common Search Space of the PDCCH to receive cell-common control information, such as dynamic scheduling or paging messages for System Information Blocks (SIBs). For example, a terminal may 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 terminals or all terminals must receive the PDCCH, it may be defined as a pre-agreed set of CCEs. Scheduling allocation information for the UE-specific PDSCH or PUSCH may be received by the terminal by examining the UE-specific Search Space of the PDCCH. The UE-specific Search Space may be defined specifically as a function of the terminal's ID (Identity) and various system parameters.

[0132] The base station may set configuration information for the search space of the PDCCH to the terminal through upper layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station may set to the terminal the number of PDCCH candidates at each aggregation level L, the monitoring period for the search space, the occasion for monitoring in slot-symbol units 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 search space, and the CORESET index to be monitored in the search space. For example, parameters for the search space of the PDCCH may include at least one of the information shown in below.

[0133]

[0134]

[0135]

[0136]

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

[0138] According to the configuration information, one or more sets of search spaces 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 a terminal-specific search space.

[0139] In a common search space, the terminal may monitor at least one of the following combinations of DCI format and RNTI. However, the scope of the present invention is not limited to the following examples.

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

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

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

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

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

[0145] In a terminal-specific search space, the terminal may monitor at least one of the following combinations of DCI format and RNTI. However, the scope of the present invention is not limited to the following examples.

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

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

[0148] RNTIs may follow at least one of the following definitions and uses.

[0149] C-RNTI (Cell RNTI): Used for terminal-specific PDSCH or PUSCH scheduling

[0150] TC-RNTI (Temporary Cell RNTI): Used for terminal-specific PDSCH scheduling

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

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

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

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

[0155] INT-RNTI (Interruption RNTI): Used to indicate whether PDSCH has been punctured.

[0156] TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to instruct power control commands to the PUSCH

[0157] TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Used to instruct power control commands to the PUCCH

[0158] TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to instruct power regulation commands to the SRS

[0159] The DCI formats described above may follow the definitions in below.

[0160]

[0161] In CORESET p and search space set s, the search space of aggregation level L can be expressed as Equation 1 below.

[0162]

[0163] - L: Lamination Level

[0164] - n CI : Carrier Index

[0165] - N CCE,p : Total number of CCEs existing in control resource set p

[0166] - n μ s,f : Slot Index

[0167] - M (L) p,s,max : Number of PDCCH candidates at assembly level L

[0168] - m snCI = 0, ..., M (L) p,s,max -1: PDCCH candidate index of aggregation level L

[0169] - i = 0, ..., L-1

[0170] - , , 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

[0171] - n RNTI : Terminal identifier

[0172] The value may be 0 for the common search space.

[0173] In the case of a terminal-specific search space, the value may correspond to a value that changes according to the terminal's ID (C-RNTI or the ID set by the base station for the terminal) and the time index.

[0174] The following describes in detail how a terminal measures channel conditions in a 5G communication system and reports them to a base station.

[0175] Channel state information (CSI) may include at least one of the following information.

[0176] - Channel Quality Indicator (CQI): CQI index indication information consisting of a modulation scheme and coding rate that satisfy the predefined minimum receive error rate of PDSCH.

[0177] - Precoding Matrix Indicator (PMI): Precoding matrix indicator information selected by the terminal

[0178] - CRI (CSI-RS resource indicator): CSI-RS information measured by the terminal

[0179] - RI (Rank Indicator): Rank indicator information selected by the terminal

[0180] - LI (Layer indicator): Indicator information for the best layer among the precoding matrices reported by the terminal

[0181] - SSBRI (SS / PBCH block resource indicator): SSB information measured by the terminal

[0182] - L1-RSRP (Reference Signal Received Power): L1 RSRP information measured by the terminal

[0183] The base station can control at least one of the time and frequency resources for the aforementioned CSI measurement and reporting of the terminal.

[0184] For CSI measurement and reporting operations, 'Aperiodic', 'Semi-Persistent', and 'Periodic' methods are supported, and the base station can configure which method to use for the terminal via signaling. Semi-persistent CSI reporting methods may support 'Semi-PersistentOnPUCCH' and 'Semi-PersistentOnPUSCH'. In the case of periodic or semi-persistent CSI reporting methods, the terminal can receive the PUCCH or PUSCH resources to transmit the CSI from the base station via upper-layer signaling. The period and slot offset of the PUCCH or PUSCH resources to transmit the CSI can be provided by the subcarrier interval setting of the uplink (UL) bandwidth part configured for CSI reporting transmission. In the case of a non-periodic CSI reporting method, the terminal can receive a PUSCH resource to transmit the CSI from the base station via L1 signaling (the aforementioned DCI format 0_1) through scheduling.

[0185] Non-periodic CSI reporting by the terminal can utilize PUSCH, and periodic CSI reporting can utilize PUCCH. Additionally, semi-permanent CSI reporting can be performed using PUSCH when triggered or activated by DCI, and using PUCCH after being activated by a MAC control element (MAC CE).

[0186] Non-periodic CSI reporting can be triggered by the "CSI request" field of the aforementioned DCI format 0_1, which corresponds to the scheduling DCI for PUSCH.

[0187] As a measure to support ultra-high-speed data services, 5G systems can support signal transmission and reception with ultra-wide bandwidths of tens to hundreds of MHz or several GHz. The above ultra-wide bandwidth signal transmission and reception can be supported through a single component carrier (CC) or through Carrier Aggregation (CA) technology that combines multiple component carriers. Carrier aggregation technology enables ultra-high-speed data services by combining individual component carriers with relatively small bandwidths to increase the total frequency bandwidth when a mobile operator has not secured a frequency bandwidth sufficient for providing ultra-high-speed data services through a single component carrier.

[0188] As described above, the frequency bands utilized by 5G systems are extensive, ranging from hundreds of MHz to tens of GHz. Figure 5 illustrates the interrelationships between frequency bands, coverage, and bandwidth. Figure 5 shows the frequency bands of the low band (501), mid band (502), high band (503), and ultra-high band (504). Generally, the lower the frequency band, the greater the coverage due to relatively lower path loss, while the higher the frequency band, the smaller the coverage due to relatively higher path loss. In low frequency bands, frequencies available for mobile communication are fragmented, resulting in small bandwidth, whereas high frequency bands are relatively easy to secure wide bandwidth frequencies, making them suitable for ultra-high-speed data services. As mobile communication systems evolve, efforts are being made to discover and utilize new frequency bands. For example, the next-generation mobile communication system, 6G (6 th In generation mobile communication systems, the 7 to 15 GHz band, called the upper midband, is being considered as one of the candidate frequencies.

[0189] Generally, mobile carriers can secure multiple frequency bands to provide mobile communication services to users. For example, a mobile carrier can operate a combined LTE and 5G system by combining existing frequency bands for LTE systems with newly secured frequency bands for 5G systems. As another example, a mobile carrier can secure frequency bands for 5G systems across multiple bands and then combine the frequencies from those bands to provide mobile communication services through 5G CA. Similarly, a 6G mobile communication system can provide mobile communication services through 6G CA by combining 6G frequencies with existing 4G or 5G frequencies, or by combining 6G frequencies with each other.

[0190] As mentioned above, since characteristics such as coverage and bandwidth vary depending on the frequency band, there is a growing trend toward mobile communication services that combine multiple frequency bands rather than those relying on a single frequency band.

[0191] According to one embodiment, as another method for supporting ultra-high-speed data services, there may be a method of increasing the data rate through a spatial multiplexing method using multiple transmitting and receiving antennas. The number of power amplifiers (PAs) required may also increase in proportion to the number of transmitting antennas equipped in a base station or terminal. The maximum output of the base station and terminal may be determined by the characteristics of the power amplifiers, and generally, the maximum output of the base station may vary depending on the cell size covered by the base station. The maximum output may be expressed in dBm units. For example, the maximum output of the terminal may be 23 dBm or 26 dBm.

[0192] According to one embodiment, as an example of a commercial 5G base station, the base station may be equipped with 64 transmitting antennas and corresponding 64 power amplifiers in the 3.5 GHz frequency band and operate at a bandwidth of 100 MHz. Consequently, the energy consumption of the base station increases in proportion to the output of the power amplifiers and the operating time of the power amplifiers. Compared to LTE base stations, 5G base stations have a relatively higher operating frequency band, so they may be characterized by having a wide bandwidth and many transmitting antennas. While this characteristic has the effect of increasing the data rate, the energy consumption of the base station may increase. Therefore, the more base stations constituting a mobile communication network there are, the greater the energy consumption of the entire mobile communication network may increase in proportion to that number.

[0193] According to one embodiment, the energy consumption of a base station may be largely determined by the operation of a power amplifier. Since the power amplifier is involved in the base station transmission operation, the downlink (DL) transmission operation of the base station is highly related to the energy consumption of the base station. Relatively speaking, the uplink (UL) reception operation of the base station may not account for a high proportion of the energy consumption of the base station. The physical channel and physical signal transmitted by the base station via the downlink may be as follows.

[0194] - PDSCH (Physical Downlink Shared Channel): A downlink data channel containing data to be transmitted to one or more terminals.

[0195] - PDCCH (Physical Downlink Control Channel): A downlink control channel containing scheduling information for PDSCH and PUSCH (Physical Uplink Control Channel). Alternatively, PDCCH alone can transmit control information such as slot formats and power control commands without the PDSCH or PUSCH to be scheduled. The scheduling information includes resource information mapped to the PDSCH or PUSCH, HARQ (hybrid automatic repeat request) related information, power control information, etc.

[0196] - PBCH (Physical Broadcast Channel): A downlink broadcast channel that provides the MIB (Master Information Block), which is essential system information required for the transmission and reception of the terminal's data and control channels.

[0197] - PSS (Primary Synchronization Signal): A signal that serves as the reference for DL ​​time / frequency synchronization and provides some cell ID information.

[0198] - SSS (Secondary Synchronization Signal): A signal that serves as the reference for DL ​​time and / or frequency (hereinafter time / frequency) synchronization and provides the cell ID and some other information.

[0199] - DM-RS (Demodulation Reference Signal): A reference signal for terminal channel estimation for each of PDSCH, PDCCH, and PBCH.

[0200] - CSI-RS (Channel-state Information Reference Signal): A downlink signal that serves as a reference for measuring the downlink channel state of a terminal.

[0201] - PT-RS (Phase-tracking Reference Signal): Downlink signal for phase tracking

[0202] According to one embodiment, from the perspective of base station energy saving, if the base station stops downlink transmission operation according to one embodiment, an energy saving effect can be expected due to the cessation of power amplifier operation. Additional energy savings may be possible by reducing the operation of other base station devices, such as baseband devices, in addition to the power amplifier. Similarly, even if uplink reception operation accounts for a relatively small proportion of the base station's total energy consumption, additional energy saving effects can be obtained if uplink reception operation can be stopped according to one embodiment.

[0203] Various methods for saving base station energy are described below with reference to FIGS. 6, FIGS. 7, FIGS. 8, and / or FIGS. 9.

[0204] - Base Station Energy Saving Method 1: The downlink transmission operation of a base station may depend on the amount of downlink traffic. For example, if there is no data to transmit to a terminal via the downlink, the base station does not need to transmit the PDCCH (physical downlink control channel) (or DCI) to schedule PDSCH and PUSCH. Alternatively, if data transmission can be temporarily deferred for reasons such as the data not being sensitive to transmission delay, the base station may not transmit the PDSCH and / or PDCCH.

[0205] FIG. 6 is a drawing illustrating an example of a base station energy saving method according to an embodiment of the present disclosure.

[0206] Referring to FIG. 6, the amount of traffic that the base station intends to transmit may be maintained above a threshold value during the T1 period (610) and the T3 period (630), and the amount of traffic that the base station intends to transmit may be maintained below a threshold value during the T2 period (620). In this case, the base station may stop or minimize the operation of the base station power amplifier, the operation of the base station RF (radio frequency) device, and / or the operation of the baseband device by not transmitting the PDSCH for data transmission and the PDCCH for scheduling PUSCH during the T2 period (620). In this case, the energy of the base station may be saved. Additionally, if the traffic intended to be processed during the T2 period (620) is not sensitive to transmission delay, the base station may defer transmission during the T2 period (620) and perform delayed transmission for the deferred transmission during the T3 period (630).

[0207] On the other hand, the base station can transmit the PDSCH (602) for data transmission and the PDCCH (601) for scheduling the PDSCH without restriction during the T1 period (610) and the T3 period (630), thereby ensuring that there is no hindrance to the provision of communication services by the base station.

[0208] For example, the base station state in the T1 interval (610) and the T3 interval (630) may be referred to as the base station normal state. For example, the base station state in the T2 interval (620) may be referred to as the base station energy saving state (ES state). The intervals exemplified above may be replaced with other terms that perform similar functions or roles, and each interval may be further subdivided or specified in relation to said functions. In one embodiment of the present disclosure, it may be exemplified as a normal state or an energy saving state. Additionally, for example, a threshold value for the amount of traffic may be communicated to the base station via signaling by an entity governing base station operations (e.g., AMF (access and mobility management function), SMF (session management function), PCF (policy control function)), or the base station may determine it on its own.

[0209] - Second method for base station energy saving: Physical channels and physical signals such as PSS, SSS, PBCH, and / or CSI (channel state information)-RS (reference signal) can be transmitted repeatedly at regular intervals regardless of data transmission to the terminal. Therefore, even if the terminal does not receive data, it can continuously update downlink time / frequency synchronization, downlink channel status, and / or radio link quality. That is, PSS, SSS, PBCH, and / or CSI-RS are essentially transmitted over the downlink regardless of downlink data traffic, which can cause base station energy consumption. Therefore, the energy consumption of the base station can be reduced by controlling the transmission of signals unrelated to (or less relevant to) data traffic to occur less frequently. This can be exemplified by FIG. 7.

[0210] FIG. 7 is a drawing illustrating an example of a base station energy saving method according to an embodiment of the present disclosure.

[0211] Referring to FIG. 7, in the T1 section (710) and T3 section (730), which are the base station normal state, the base station can transmit periodic signals (703), such as PSS, SSS, PBCH, and / or CSI-RS, at a predefined first transmission period (701). On the other hand, in the T2 section (720), which is the base station power saving state, the base station can transmit periodic signals (704) at a second transmission period (702), which is relatively longer than the first transmission period (701), thereby intermittently performing or minimizing the operation of the base station power amplifier, base station RF device, and / or baseband device. In this case, the energy consumption of the base station can be reduced.

[0212] - Third method for saving base station energy: The base station can reduce energy consumption by switching off at least a part of the base station's antenna or power amplifier. For example, this can be illustrated through FIG. 8.

[0213] FIG. 8 is a diagram showing an example of a base station energy saving method according to one embodiment of the present disclosure.

[0214] Referring to FIG. 8, in the base station normal state, during the T1 period (810) and T3 period (830), the base station can transmit a downlink signal based on a predefined first transmission power or M1 transmission antennas (801). On the other hand, in the base station power saving state, during the T2 period (820), the base station can stop or minimize the operation of the base station power amplifier, base station RF device, and / or baseband device, etc., by transmitting a downlink signal based on a second transmission power smaller than the first transmission power or M2 transmission antennas (802) relatively fewer than the M1 transmission antennas (801). In this case, the energy consumption of the base station can be reduced.

[0215] - Fourth method for saving base station energy: In an environment where Carrier Aggregation (CA) is applied, when the amount of traffic the base station intends to transmit is kept below a threshold value, the base station may transmit the traffic through one or more configuration carriers (CC), and by switching off the remaining configuration carriers (or specific one or more configuration carriers), the operation of power amplifiers, RF devices, and / or baseband devices associated with the switched-off configuration carriers may be stopped or minimized. In this case, the energy consumption of the base station may be reduced. This can be illustrated through FIG. 9.

[0216] FIG. 9 is a diagram showing an example of a base station energy saving method according to one embodiment of the present disclosure.

[0217] Referring to FIG. 9, the operation of a first configuration carrier (901) and a second configuration carrier (902) as a carrier bundle is exemplified. In FIG. 9, the amount of traffic that the base station intends to transmit during the T1 period (910) and the T3 period (930) may be maintained at a level higher than a threshold value, and the amount of traffic that the base station intends to transmit during the T2 period (920) may be maintained at a level lower than a threshold value. In this case, to save energy, the base station may operate the T2 period (920) in a base station power saving state, switch off the second configuration carrier (902), and have the first configuration carrier (901) handle the traffic processing during the T2 period (920). On the other hand, during the base station normal state in the T1 period (910) and the T3 period (930), both the first configuration carrier (901) and the second configuration carrier (902) are activated to quickly process a relatively large amount of traffic.

[0218] According to one embodiment, the base station energy saving methods 1, 2, 3, and / or 4 may be applied and operated individually, or one or more may be combined and operated.

[0219] According to one embodiment, the base station state is represented in two stages: a base station general state and a base station power saving state, but this is merely an example, and the base station power saving state can be distinguished in more detail. For example, the base station power saving state can be distinguished in conjunction with the base station's energy saving method. Specifically, for example, the first base station power saving state represents the base station power saving state according to the first base station energy saving method, the second base station power saving state represents the base station power saving state according to the second base station energy saving method, the third base station power saving state represents the base station power saving state according to the third base station energy saving method, and the fourth base station power saving state represents the base station power saving state according to the fourth base station energy saving method.

[0220] The operation of the system proposed in the present disclosure is explained below through specific embodiments.

[0221] According to one embodiment of the present invention, even if the base station is in a base station power saving state, the base station may transmit a discovery signal to the terminal to facilitate base station identification. Upon detecting the discovery signal, the terminal may request the base station to transmit a synchronization signal, and the base station may transmit a synchronization signal to the terminal in response to the terminal's request. Through such a series of procedures, the terminal is able to connect to the base station that is in a base station power saving state. In the present disclosure, the base station may have a dedicated block for processing the discovery signal to enhance the base station power saving effect.

[0222] The following initial access procedure may be understood to include at least one of the following: the transmission and reception of discovery signals between the terminal and the base station, terminal request signals, synchronization signals, and system information, and the random access procedure between the terminal and the base station. Subsequently, the terminal may request an attach to the network, and after the attach procedure is completed, may transmit and receive packets (or data) through the network.

[0223] The following is a description of each specific embodiment. The present invention may include a plurality of embodiments, each of which is distinguished for convenience to explain the implementation according to the present disclosure and may be implemented independently; however, as long as they are not mutually exclusive, all or part of the plurality of embodiments may be selectively combined and implemented. Such combinations include various variations and modifications of the present invention and may be made in various ways depending on technical needs or application environments. Even if the plurality of embodiments use different approaches to achieve the purpose of the invention, they may be used simultaneously or complementarily as long as the embodiments of the present invention are not technically mutually exclusive. Such combinations may be varied depending on technical requirements or specific application cases, and the present invention may encompass various embodiments including such variations and combinations. Although the name of a 5G system is used to describe the embodiments of the present disclosure, this is merely an example and can be understood as a message that includes information or performs the same role as described below.

[0224] <1st Embodiment>

[0225] The first embodiment describes an example of base station operation for processing the discovery signal described above.

[0226] The terminal initial connection procedure of the first embodiment can be described by dividing it into Phase 1 and Phase 2 before and after the transmission time of the base station's normal synchronization signal or SSB.

[0227] A base station or terminal may transmit or receive at least some of the following signals during Phase 1.

[0228] - Discovery signal transmitted by a base station to a terminal to notify the presence of a base station or cell: Similar to a synchronization signal, the discovery signal can be a sequence-based signal and can be composed of one or a combination of multiple sequences. By detecting the discovery signal, the terminal can recognize that a cell transmitting the discovery signal is present in the vicinity of the terminal. The discovery signal can be transmitted periodically, and by transmitting it with a relatively long transmission periodicity, a power saving effect for the base station can be expected during the period when the discovery signal is not transmitted.

[0229] - A terminal request signal in which a terminal requests the base station to transmit a synchronization signal or an SSB: If the terminal succeeds in detecting a discovery signal, it may request the transmission of a synchronization signal or an SSB to the corresponding cell. By applying a pre-agreed configuration and format to the terminal request signal, the processing complexity for the base station to receive the terminal request signal can be reduced. Alternatively, the discovery signal may indicate the configuration and format of the terminal request signal within a certain limited range.

[0230] - On-demand SSB transmitted by the base station in response to a terminal request: From the on-demand SSB, the terminal can synchronize time and frequency. The on-demand SSB is an SSB transmitted in response to a terminal request, and may be transmitted once, transmitted a fixed number of times (N), or transmitted for a fixed time interval (W). The N and W exemplified above may use pre-agreed values ​​or may be set by the base station for the terminal. The base station may transmit an on-demand synchronization signal as a modified example of the on-demand SSB. The on-demand synchronization signal is a synchronization signal transmitted in response to a terminal request.

[0231] The base station or terminal may transmit or receive at least some of the following signals during Phase 2.

[0232] - Synchronization signal or SSB transmitted by the base station to the terminal: It is a reference signal that enables the terminal to synchronize time and frequency, and provides a cell identifier. The synchronization signal is transmitted periodically and is transmitted with a relatively short transmission periodicity compared to the discovery signal.

[0233] - A PDCCH for scheduling the SIB that the base station transmits to the terminal (hereinafter, it may be exemplified as the SIB PDCCH).

[0234] - A PDSCH that carries the SIB transmitted by the base station to the terminal (hereinafter, this may be exemplified as a SIB PDSCH).

[0235] - Random access preamble transmitted by the terminal to the base station

[0236] FIG. 10 is a diagram illustrating an initial connection procedure of a terminal utilizing a discovery signal according to one embodiment of the present disclosure.

[0237] Referring to FIG. 10 below, an initial connection procedure of a terminal utilizing a discovery signal according to a first embodiment is illustrated. First, a base station (1030) can transmit a discovery signal (1001). The discovery signal is a cell-common signal and may have the characteristic of being transmitted with a relatively long transmission period. Even if the base station is in a power-saving state, the base station can notify terminals within the cell coverage of the presence of the base station by transmitting the discovery signal. A terminal that has successfully detected the discovery signal can transmit a terminal request signal (1002) to the base station to request the transmission of an on-demand SSB. Upon receiving the terminal request signal, the base station can transmit an on-demand SSB (1003) in accordance with the terminal request. In FIG. 10, the step of the base station and the terminal transmitting and receiving the discovery signal, the terminal request signal, and the on-demand SSB can be illustrated as Phase 1 (1010). Subsequently, in Phase 2 (1020), the base station may transmit an SSB (1004) to the terminal to enable the terminal to synchronize time and frequency and obtain a cell identifier. Then, the terminal may obtain control information related to the SIB PDCCH to be received in the next step (e.g., time and / or frequency resource information of the SIB PDCCH) from the MIB obtained through the SSB. Subsequently, the terminal may obtain a SIB by receiving the SIB PDCCH (1005) and the SIB PDSCH (1006). The SIB may contain cell-common transmission and reception control information. The terminal may transmit a random access preamble (1007) by referring to the control information of the SIB.

[0238] As described above, the discovery signal has the characteristic of being transmitted with a relatively long transmission period, while the SSB has the characteristic of being transmitted with a relatively short transmission period.

[0239] FIG. 11 is a drawing showing an example of an antenna configuration of a base station according to one embodiment of the present disclosure.

[0240] The following is an example of a base station antenna configuration with reference to FIG. 11. The base station antenna may consist of the following components:

[0241] - A pair of dual-polarized antenna elements (AE): Typically, the antenna elements (1121, 1122) can be composed of microstrip (patch) antennas. When these antenna elements are co-polarized, two mutually orthogonal signals can be transmitted and received simultaneously without additional array gain. The co-polarization of the antenna elements acts as a well-isolated spatial path for diversity and spatial multiplexing, and can be achieved without increasing the size of the antenna.

[0242] - Antenna Subarray: Applying independent digital beamforming to all antenna elements can be inefficient in terms of development costs and cell angle coverage. The azimuth and elevation angles of the signal that the base station intends to transmit may be limited to a specific range depending on the geometric distribution of the user. Additionally, since base station antennas are typically installed at high locations such as rooftops, they do not need to have a full vertical range of -90 to 90 degrees, which can lead to unnecessary transmission power loss. Therefore, a small number of adjacent antenna elements can be grouped together, and a single RF (radio frequency) transmit / receive chain (including a power amplifier and a low-noise amplifier) ​​can be connected to the group to operate as an antenna subarray structure. In FIG. 11, the antenna subarray (1110) consists of two antenna elements (N subIt indicates that it is composed of =2). A single digital beamforming weight may be applied within the antenna subarray, and additional RF components, such as a phase converter, may be required to adjust the steering angle of the antenna subarray.

[0243] - Antenna panel: A base station can configure an antenna panel by arranging antenna sub-arrays in two dimensions, horizontally and vertically. According to FIG. 11, four antenna sub-arrays in the vertical direction and four antenna sub-arrays (N) in the horizontal direction V =4, N H It indicates that the antenna panel is configured as =4). Also, the spacing between adjacent antenna elements in the vertical direction is d H (1123), the spacing between adjacent antenna elements in the horizontal direction is d V (1124) indicates that it is.

[0244] A base station can configure a base station antenna by combining one or more antenna panels. According to FIG. 11, the base station antenna is configured with two antenna panels in the vertical direction and two antenna panels in the horizontal direction (M=2, N=2). The base station may, as needed, [use] the above N sub , N V , N H, Various antenna configurations can be created by adjusting M, N, etc.

[0245] According to the first embodiment, the base station can increase the base station power saving effect by using a dedicated block for processing the discovery signal.

[0246] Referring to FIG. 12 below, an operation in which a base station uses a dedicated block for processing a discovery signal is exemplified.

[0247] FIG. 12 is a drawing showing an example of an antenna configuration of a base station according to one embodiment of the present disclosure.

[0248] In FIG. 12, details regarding the configuration can be referenced from the description in FIG. 11. However, FIG. 12 may differ in that an antenna for processing discovery signals is configured separately. FIG. 12 indicates that an antenna sub-array (1213) is allocated as an antenna sub-array dedicated to discovery signals. Therefore, when a base station transmits a discovery signal to a terminal, it can transmit the discovery signal using the antenna sub-array set (1213, hereinafter antenna sub-array set #1) dedicated to discovery signals. When a base station transmits a signal other than discovery, it transmits it using the remaining antenna sub-array set (1214, hereinafter antenna sub-array set #2), excluding the antenna sub-array set #1. Therefore, when a base station does not need to transmit a signal other than a discovery signal, it can reduce base station power consumption by switching off antenna sub-array set #2. In addition, when a base station transmits a discovery signal, the base station's power consumption can be reduced by using antenna subarray set #1, which consists of relatively few antenna elements. That is, when a base station transmits a discovery signal to a terminal, a reduction in base station power consumption can be expected by using one or more antenna elements from the antenna panel instead of using the entire antenna subarray. In addition, each example antenna subarray set can be utilized by subdividing it into detailed categories according to its purpose.

[0249] Referring to FIG. 13 below, an operation in which a base station uses a dedicated block for processing a discovery signal is exemplified.

[0250] FIG. 13 is a drawing showing an example of an antenna configuration of a base station according to one embodiment of the present disclosure.

[0251] In FIG. 13, details regarding the configuration can be referenced from the description in FIG. 11. However, FIG. 13 may differ in that an antenna panel for processing discovery signals is configured separately. FIG. 13 indicates that an antenna panel (1336) is assigned as an antenna panel dedicated to discovery signals. Therefore, when a base station transmits a discovery signal to a terminal, it can transmit the discovery signal using the antenna panel (1336) dedicated to discovery signals. When a base station transmits a signal other than discovery, it can transmit it using the remaining antenna panels (1333, 1334, 1335) excluding the antenna panel (1336). Therefore, when a base station does not need to transmit a signal other than discovery signals, it can reduce base station power consumption by switching off the remaining antenna panels (1333, 1334, 1335). In addition, when the base station transmits a discovery signal, the base station's power consumption can be reduced by using an antenna panel (1336) composed of relatively few antenna elements. That is, when the base station transmits a discovery signal to a terminal, the base station's power consumption can be reduced by using one or more antenna panels from a plurality of antenna panel structures rather than using all of the antenna panels. In addition, each of the remaining antenna panels exemplified can be utilized by subdividing them in detail according to their purpose.

[0252] In the description of FIG. 12 or FIG. 13 above, the processing block dedicated to the discovery signal is not limited to an antenna. For example, the operation of a power amplifier, filter, RFIC, etc., associated with an antenna dedicated to the discovery signal can also be configured to be dedicated to the discovery signal.

[0253] According to one embodiment, a processing block dedicated to the discovery signal can be used to receive the terminal request signal described above.

[0254] According to one embodiment, the operating frequency of the processing block dedicated to the discovery signal, as exemplified above, can be operated differently from the rest of the blocks. As described above, a lower frequency band allows for wider coverage due to less path loss, and a higher frequency band is suitable for ultra-high-speed data services through a wider bandwidth. For example, a base station can provide ultra-high-speed data services by transmitting PDCCH and PDSCH in the 3.5 GHz frequency band, and provide wide coverage by transmitting the discovery signal in the 800 MHz frequency band.

[0255] As a modified example of the first embodiment, a processing block dedicated to discovery signals can be used for the discovery signal transmitted by the base station to the terminal during the above-described phase 1, the on-demand SSB, and the terminal request signal received by the base station.

[0256] Although the names of 5G systems have been used to describe the embodiments of the present disclosure, the names described above, such as discovery signal, on-demand SSB, SSB, PSS, SSS, PBCH, PDCCH, PDSCH, etc., are merely examples and can be understood as messages that include information or perform the same role as described above.

[0257] <Second Embodiment>

[0258] The second embodiment describes operations related to the terminal and the base station during the initial connection procedure of the terminal utilizing the discovery signal described above.

[0259] FIG. 14 is a diagram showing an example of an initial connection procedure of a terminal according to one embodiment of the present disclosure.

[0260] According to FIG. 14, in step 1401, the terminal may attempt to detect a discovery signal transmitted by the base station. In one embodiment, the discovery signal may be transmitted to the terminal through a dedicated processing block of the base station. Accordingly, the terminal may detect the discovery signal through corresponding discovery signal reception processing.

[0261] In step 1402, when the terminal successfully detects a discovery signal, the terminal recognizes that there is a cell around the terminal, and the terminal can transmit a terminal request signal to the base station to request the transmission of an on-demand SSB.

[0262] In step 1403, the terminal that transmitted the terminal request signal can receive an on-demand SSB from the base station.

[0263] In step 1404, a terminal that has received an on-demand SSB may receive an SSB from a base station. The terminal may perform downlink time and frequency synchronization from the SSB received from the base station and obtain a cell identifier (cell ID). In one embodiment, the SSB may include at least one of a synchronization signal and a PBCH. In one embodiment, the terminal may obtain a system information MIB in step 1404. In one embodiment, the terminal may receive a PBCH using the cell ID obtained from the synchronization signal and obtain a system information MIB from the PBCH. In one embodiment, the MIB may include at least one of CORESET information or PDCCH configuration information, which are time-frequency resources to which the PDCCH is mapped.

[0264] In step 1405, the terminal can monitor the SIB PDCCH by referring to the acquired PDCCH configuration information. The terminal can obtain system information (e.g., SIB) by receiving the SIB PDCCH from the scheduling information of the SIB PDCCH. The SIB includes cell-common transmission and reception control information, which may include, for example, random access control information, paging control information, and common control information for various physical channels.

[0265] In step 1406, the terminal can proceed with a random access procedure.

[0266] The steps described above may be modified, omitted, changed in order, or undesired steps may be added to carry out the present invention. In one embodiment, the on-demand SSB may be transmitted to a terminal through a dedicated processing block of a base station. Accordingly, the terminal may receive the on-demand SSB through corresponding on-demand SSB reception processing.

[0267] FIG. 15 is a diagram showing an example of a base station procedure for supporting a terminal initial connection procedure according to one embodiment of the present disclosure.

[0268] According to FIG. 15, in step 1501, the base station may transmit a discovery signal to terminals within cell coverage to notify them of the presence of the base station. In one embodiment, the base station may transmit the discovery signal to the terminal after processing by a processing block dedicated to the discovery signal.

[0269] In step 1502, the base station can receive a terminal request signal transmitted by the terminal.

[0270] In step 1503, the base station that receives the terminal request signal can transmit an on-demand SSB to the terminal in response to the terminal request signal.

[0271] In step 1504, the base station that transmitted the on-demand SSB can transmit the SSB to the terminal. In one embodiment, the SSB includes at least one of a synchronization signal and a PBCH.

[0272] In step 1505, the base station may transmit a SIB PDCCH and a SIB PDSCH to transmit the SIB to the terminal. The SIB contains cell-common transmission and reception control information, which may include, for example, random access control information, paging control information, and common control information for various physical channels.

[0273] In step 1506, the base station may proceed with a random access procedure based on a terminal request.

[0274] The steps described above may be modified, omitted, changed in order, or undesired steps may be added to perform the present invention. In one embodiment, the on-demand SSB may be transmitted to a terminal through a dedicated processing block of a base station. In one embodiment, the terminal request signal may be received through a dedicated processing block of a base station.

[0275] Hereinafter, a scenario in which a base station equipped with the discovery signal transmission function and a base station not equipped with the discovery signal transmission function coexist in a mobile communication network will be described. Refer to FIGS. 16 and FIGS. 17 to explain the above scenario.

[0276] FIG. 16 is a diagram showing an example of a mobile communication network scenario according to one embodiment of the present disclosure.

[0277] In the example of FIG. 16, the first base station (1601) is a base station equipped with a discovery signal transmission function, and the second base station (1602) is a base station not equipped with a discovery signal transmission function. If the terminal (1603) is located in the coverage overlapping area of ​​the first base station (1601) and the second base station (1602), the terminal operation can be defined according to the procedure of FIG. 17.

[0278] FIG. 17 is a diagram showing an example of an initial connection procedure of a terminal according to one embodiment of the present disclosure.

[0279] According to FIG. 17, in step 1701, the terminal may attempt to detect the discovery signal and / or SSB transmitted by the base station.

[0280] In step 1702, the terminal can check whether it has detected a discovery signal or an SSB.

[0281] If the terminal successfully detects a discovery signal, the terminal recognizes that there is a cell around the terminal, and in step 1703, the terminal can transmit a terminal request signal to the base station to request the transmission of an on-demand SSB.

[0282] In step 1704, the terminal that transmitted the terminal request signal can receive an on-demand SSB from the base station.

[0283] In step 1705, a terminal that has received an on-demand SSB can receive an SSB from a base station. The terminal can perform downlink time and frequency synchronization from the SSB received from the base station and obtain a cell identifier (cell ID). In one embodiment, the SSB may include at least one of a synchronization signal and a PBCH. In one embodiment, the terminal can obtain a system information MIB in step 1705. In one embodiment, the terminal can receive a PBCH using the cell ID obtained from the synchronization signal and obtain a system information MIB from the PBCH. In one embodiment, the MIB may include at least one of CORESET information or PDCCH configuration information, which are time-frequency resources to which the PDCCH is mapped.

[0284] In step 1706, the terminal can monitor the SIB PDCCH by referring to the acquired PDCCH configuration information. The terminal can obtain system information (e.g., SIB) by receiving the SIB PDCCH from the scheduling information of the SIB PDCCH. The SIB includes cell-common transmission and reception control information, which may include, for example, random access control information, paging control information, and common control information for various physical channels.

[0285] In step 1707, the terminal can proceed with a random access procedure.

[0286] If, in step 1702 above, the terminal successfully detects the SSB, the terminal can perform the procedure of step 1706.

[0287] According to one embodiment, in step 1702, if the terminal successfully detects both the discovery signal and the SSB, the terminal may proceed to the next procedure according to at least one of the following procedures.

[0288] - Method 1: The terminal may proceed to the next procedure depending on the signal it successfully detects first. For example, if the terminal successfully detects the discovery signal before the SSB by at least a time gap T, it may perform the procedure of step 1703. However, if the terminal successfully detects the SSB before the discovery signal by at least a time gap T, it may perform the procedure of step 1706. The time gap T may be a value agreed upon between the terminal and the base station, or the base station may inform the terminal through signaling.

[0289] - Method 2: The received signal strength of the discovery signal detected by the terminal (RSRP1) and the received signal strength of the SSB (RSRP2) can be compared, and the following procedure can be performed according to the signal with the higher received signal strength. For example, if RSRP1 > RSRP2, the procedure of step 1703 can be performed, and if RSRP1 < RSRP2, the procedure of step 1706 can be performed. In this case, RSRP1 and RSRP2 can be compared by reflecting a measurement offset in the terminal's measurement value to correct for differences in the transmission characteristics and transmission methods of the discovery signal and the SSB. For example, 'RSRP1 + measurement offset' can be compared with RSRP2, or RSRP1 can be compared with 'RSRP2 + measurement offset'. The above measurement offset can be a value agreed upon between the terminal and the base station, or the base station can inform the terminal of it through signaling.

[0290] The steps described above may be modified, omitted, changed in order, or undesired steps may be added to perform the present invention. In one embodiment, the discovery signal may be transmitted to a terminal through a dedicated processing block of a base station. Accordingly, the terminal may receive the discovery signal through a corresponding discovery signal reception processing.

[0291] The base station procedure corresponding to FIG. 17 above can be explained with reference to FIG. 15 above. If the base station is equipped with a discovery signal transmission function, the base station procedure corresponding to FIG. 17 above can refer to the procedure of FIG. 15 above. If the base station is not equipped with a discovery signal transmission function, the base station can proceed from the procedure of step 1504 of FIG. 15 above.

[0292] Although the name of a 5G system has been used to describe an embodiment of the present disclosure, the name described above is merely an example and can be understood as a message that includes information or performs the same role as described above.

[0293] FIG. 18 is a drawing showing a terminal transceiver device according to one embodiment of the present disclosure. For convenience of explanation, devices not directly related to the present disclosure may be omitted from illustration and description.

[0294] Referring to FIG. 18, the terminal may be configured to include at least one of a transmitter (1804) composed of an uplink transmission processing block (1801), a multiplexer (1802), and a transmission RF block (1803), a receiver (1808) composed of a downlink reception processing block (1805), a demultiplexer (1806), and a reception RF block (1807), and a control unit (1809). The control unit (1809) can control each of the configuration blocks of the receiver (1808) 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 (1804) for transmitting an uplink signal.

[0295] In the transmission unit (1804) of the terminal, the uplink transmission processing block (1801) 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 (1801) can be multiplexed with other uplink signals by a multiplexer (1802), then processed by a transmission RF block (1803), and then transmitted to a base station.

[0296] The receiving unit (1808) of the terminal can demultiplex a signal received from a base station and distribute it to each downlink receiving processing block. The downlink receiving processing block (1805) can obtain control information or data transmitted by the base station by performing processes such as demodulation and channel decoding on the downlink signal of the base station. The receiving unit (1808) of the terminal can apply the output result of the downlink receiving processing block to the control unit (1809) to support the operation of the control unit (1809).

[0297] FIG. 19 is a block diagram illustrating the structure of a terminal according to one embodiment of the present disclosure.

[0298] As illustrated in FIG. 19, the terminal of the present disclosure may include at least one of a processor (1930), a transceiver (1910), or a memory (1920). However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more components or fewer components than the components described above. Furthermore, the processor (1930), the transceiver (1910), and the memory (1920) may be implemented in the form of a single chip. According to one embodiment, the transceiver (1910) of FIG. 19 may include the transceiver (1804) and the receiver (1808) of FIG. 18. Additionally, the processor (1930) of FIG. 19 may include the control unit (1809) of FIG. 18.

[0299] According to one embodiment, the processor (1930) can control a series of processes that allow the terminal to operate according to the above-described embodiment of the present disclosure. For example, according to the embodiment of the present disclosure, the components of the terminal can be controlled to perform a transmission and reception method of the terminal according to a discovery signal of a base station. The processor (1930) may include at least one processor, and the processor (1930) can perform a transmission and reception operation of the terminal in a wireless communication system applying the operation of the above-described present disclosure by executing a program stored in memory (1920).

[0300] The transceiver (1910) can transmit and receive signals with a base station. The signals transmitted and received with the base station may include control information and data. The transceiver (1910) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely an example of the transceiver (1910), and the components of the transceiver (1910) are not limited to an RF transmitter and an RF receiver. Additionally, the transceiver (1910) can receive a signal through a wireless channel and output it to a processor (1930), and transmit the signal output from the processor (1930) through a wireless channel.

[0301] According to one embodiment, the memory (1920) may store programs and data necessary for the operation of the terminal. Additionally, the memory (1920) may store control information or data included in signals transmitted and received by the terminal. The memory (1920) may be composed of a storage medium or a combination of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memory (1920). According to one embodiment, the memory (1920) may store a program for performing the transmission and reception operation of the terminal according to the discovery signal of the base station, which is one of the embodiments of the present disclosure described above.

[0302] FIG. 20 is a block diagram illustrating the structure of a base station according to one embodiment of the present disclosure.

[0303] As illustrated in FIG. 20, the base station of the present disclosure may include at least one of a processor (2030), a transceiver (2010), or a memory (2020). However, the components of the base station are not limited to the examples described above. For example, the base station may include more components or fewer components than the components described above. In addition, the processor (2030), the transceiver (2010), and the memory (2020) may be implemented in the form of a single chip.

[0304] The processor (2030) can control a series of processes to enable the base station to operate according to the embodiments of the present disclosure described above. For example, according to the embodiments of the present disclosure, the processor (2030) can control the components of the base station to control the discovery signal transmission block of the base station and to perform a method of scheduling a terminal according to the discovery signal of the base station. The processor (2030) may include at least one processor, and the processor (2030) can perform a method of scheduling a terminal according to the frequency instruction of the base station of the present disclosure described above by executing a program stored in memory (2020).

[0305] The transceiver (2010) can transmit and receive signals with a terminal. The signals transmitted and received with the terminal may include control information and data. The transceiver (2010) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely an example of the transceiver (2010), and the components of the transceiver (2010) are not limited to an RF transmitter and an RF receiver. Additionally, the transceiver (2010) can receive a signal through a wireless channel and output it to a processor (2030), and transmit the signal output from the processor (2030) through a wireless channel.

[0306] According to one embodiment, the memory (2020) may store programs and data necessary for the operation of the base station. Additionally, the memory (2020) may store control information or data included in signals transmitted and received by the base station. The memory (2020) may be composed of a storage medium or a combination of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memory (2020). According to one embodiment, the memory (2020) may store a program for controlling the discovery signal transmission block of the base station, which is one of the embodiments of the present disclosure described above, and for performing a method of scheduling a terminal according to the discovery signal of the base station.

[0307] In the specific embodiments of the present disclosure described above, the components included in the present disclosure are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural, it may be composed of a singular form, or even if a component is expressed in the singular form, it may be composed of a plural form.

[0308] Meanwhile, the present specification and drawings disclose preferred embodiments of the present disclosure. Although specific terms have been used, they are used merely in a general sense to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the invention, and are not intended to limit the scope of the present disclosure. It is obvious to those skilled in the art that, in addition to the embodiments disclosed herein, other variations based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments may be combined and operated as needed. For example, the first, second, and third embodiments may be implemented independently, or at least one of the embodiments may be combined and implemented.

[0309] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

In a method performed by a base station of a wireless communication system, A step of transmitting a discovery signal to a terminal; A step of receiving a request related to a synchronization signal from the above terminal; A step of transmitting an on-demand SSB (synchronization signal block) to the above terminal; and It includes a step of performing a random access procedure, The above discovery signal is transmitted based on a block for transmitting the discovery signal from the antenna of the base station, and A method characterized in that the above block is not used for signal transmission other than the discovery signal. In Article 1, The above block includes one or more antenna panels for the discovery signal, and A method characterized in that the above one or more antenna panels are not used for transmitting signals other than the discovery signal at the base station. In Article 1, The above block includes a set of antenna subarrays for the discovery signal of the antenna panel, and The above antenna subarray set includes one or more antenna subarrays, and A method characterized in that the above one or more antenna sub-arrays are not used for transmitting signals other than the discovery signal at the base station. In Article 1, The above-mentioned on-demand SSB is broadcast based on at least one of a period longer than the SSB, a fixed number of times, or a fixed time interval, and A method characterized in that the priority of the discovery signal is determined based on the SSB, RSRP (reference signal received power) information, or time information in which the terminal receives the discovery signal and the SSB. In a method performed by a terminal of a wireless communication system, A step of receiving a discovery signal from a base station; A step of transmitting a request related to a synchronization signal to the above base station; A step of receiving an on-demand SSB (synchronization signal block) from the base station; and It includes a step of performing a random access procedure, The above discovery signal is transmitted based on a block for transmitting the discovery signal from the antenna of the base station, and A method characterized in that the above block is not used for signal transmission other than the discovery signal. In Article 5, The above block includes one or more antenna panels for the discovery signal, and A method characterized in that the above one or more antenna panels are not used for transmitting signals other than the discovery signal at the base station. In Article 5, The above block includes a set of antenna subarrays for the discovery signal of the antenna panel, and The above antenna subarray set includes one or more antenna subarrays, and The above one or more antenna subarrays are not used by the base station for transmitting signals other than the discovery signal, and The above-mentioned on-demand SSB is broadcast by the base station based on at least one of a period longer than the SSB, a fixed number of times, or a fixed time interval, and A method characterized in that the priority of the discovery signal is determined based on the SSB, RSRP (reference signal received power) information, or time information in which the terminal receives the discovery signal and the SSB. In a base station of a wireless communication system, Transmitter / receiver; and It includes a control unit connected to the above-mentioned transceiver, transmitting a discovery signal to a terminal, receiving a request related to a synchronization signal from the terminal, transmitting an on-demand synchronization signal block (SSB) to the terminal, and performing a random access procedure. The above discovery signal is transmitted based on a block for transmitting the discovery signal from the antenna of the base station, and A base station characterized in that the above block is not used for signal transmission other than the discovery signal. In Article 8, The above block includes one or more antenna panels for the discovery signal, and The above one or more antenna panels are a base station characterized in that the base station is not used for transmitting signals other than the discovery signal. In Article 8, The above block includes a set of antenna subarrays for the discovery signal of the antenna panel, and The above antenna subarray set includes one or more antenna subarrays, and The above one or more antenna sub-arrays are a base station characterized in that the base station is not used for transmitting signals other than the discovery signal. In Article 8, The above-mentioned on-demand SSB is broadcast based on at least one of a period longer than the SSB, a fixed number of times, or a fixed time interval, and A base station characterized in that the priority of the discovery signal is determined based on the SSB, RSRP (reference signal received power) information, or time information in which the terminal receives the discovery signal and the SSB. In a terminal of a wireless communication system, Transmitter / receiver; and It includes a control unit connected to the above-mentioned transceiver, receiving a discovery signal from a base station, transmitting a request related to a synchronization signal to the base station, receiving an on-demand synchronization signal block (SSB) from the base station, and performing a random access procedure. The above discovery signal is transmitted based on a block for transmitting the discovery signal from the antenna of the base station, and A terminal characterized in that the above block is not used for signal transmission other than the discovery signal. In Article 12, The above block includes one or more antenna panels for the discovery signal, and A terminal characterized in that the above one or more antenna panels are not used for transmitting signals other than the discovery signal at the base station. In Article 12, The above block includes a set of antenna subarrays for the discovery signal of the antenna panel, and The above antenna subarray set includes one or more antenna subarrays, and A terminal characterized in that the above one or more antenna sub-arrays are not used for transmitting signals other than the discovery signal at the base station. In Article 12, The above-mentioned on-demand SSB is broadcast by the base station based on at least one of a period longer than the SSB, a fixed number of times, or a fixed time interval, and A terminal characterized in that the priority of the above discovery signal is determined based on the above SSB, RSRP (reference signal received power) information, or time information in which the terminal receives the above discovery signal and the above SSB.

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