Apparatus and method for transmitting and receiving cell discovery signal in wireless communication system

Abstract

The purpose of the present invention is to transmit and receive a cell discovery signal in a wireless communication system. A method of operating a terminal may include: receiving at least one synchronization signal and a broadcast channel block (SSB); obtaining synchronization with the base station by using the synchronization signal included in the SSB; obtaining system information based on a master information block (MIB) included in the SSB; performing a random access process based on the system information; sending a message for requesting the base station to send the discovery signal; and tracking at least one of time or frequency based on the discovery signal.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting and receiving a cell discovery signal in a wireless communication system. Background Art

[0002] Wireless communication systems have been widely deployed to provide various types of communication services, such as voice or data. Generally speaking, wireless communication systems are multiple access systems that support communication for multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single carrier frequency division multiple access (SC-FDMA) systems.

[0003] In particular, since a large number of communication devices require a large communication capacity, an enhanced mobile broadband (eMBB) communication technology is being proposed compared to a conventional radio access technology (RAT). In addition, not only a large-scale machine type communication (massive MTC) that provides various services anytime and anywhere by connecting multiple devices and objects is being proposed, but also a communication system that takes into account services / user terminal devices (UEs) that are sensitive to reliability and latency is being proposed. Various technical configurations are proposed for this purpose. Summary of the invention

[0004] Technical issues

[0005] The present disclosure may provide an apparatus and method for efficiently using a cell discovery signal in a wireless communication system.

[0006] The present disclosure may provide an apparatus and method for reducing energy consumption caused by transmitting a Tracking Reference Signal (TRS) in a wireless communication system.

[0007] The present disclosure may provide an apparatus and method for utilizing various structures of a cell discovery signal in a wireless communication system.

[0008] The present disclosure may provide an apparatus and method for using a cell discovery signal having a multiplexing structure of a synchronization signal and a broadcast channel block (SSB) and a modified structure of the SSB in a wireless communication system.

[0009] The present disclosure may provide an apparatus and method for requesting transmission of a cell discovery signal in a wireless communication system.

[0010] The present disclosure may provide an apparatus and method for providing information related to resources occupied by a cell discovery signal in a wireless communication system.

[0011] The present disclosure may provide an apparatus and method for providing necessary information for performing rate matching in consideration of resources occupied by a cell discovery signal in a wireless communication system.

[0012] The present disclosure may provide an apparatus and method for controlling uplink transmission for a duration including resources occupied by a cell discovery signal in a wireless communication system.

[0013] The present disclosure may provide an apparatus and method for managing a random access channel opportunity (RO) or a physical uplink shared channel opportunity (PO) corresponding to a cell discovery signal in a wireless communication system.

[0014] The present disclosure may provide an apparatus and method for providing additional configuration information by using a cell discovery signal in a wireless communication system.

[0015] The technical objectives to be achieved by the present disclosure are not limited to the contents mentioned above, and those skilled in the art to which the technical configuration of the present disclosure is applied can consider other technical objectives not mentioned therein from the embodiments of the present disclosure to be described below.

[0016] Technical Solution

[0017] As an example of the present disclosure, a method for operating a terminal in a wireless communication system may include: receiving at least one synchronization signal and a broadcast channel block (SSB); obtaining synchronization with a base station by using a synchronization signal included in the SSB; obtaining system information based on a master information block (MIB) included in the SSB; performing a random access procedure based on the system information; sending a message to the base station for requesting the sending of an SSB-based discovery signal, and performing tracking for at least one of time and frequency based on the discovery signal.

[0018] As an example of the present disclosure, a method for operating a base station in a wireless communication system may include: sending at least one synchronization signal and a broadcast channel block (SSB); sending system information related to a random access channel; performing a random access procedure based on the system information; receiving a message for requesting the base station to send an SSB-based discovery signal; and sending a discovery signal.

[0019] As an example of the present disclosure, a terminal in a wireless communication system may include a transceiver and a processor connected to the transceiver, and the processor may be configured to receive at least one synchronization signal and a broadcast channel block (SSB), obtain synchronization with a base station by using the synchronization signal included in the SSB, obtain system information based on a master information block (MIB) included in the SSB, perform a random access procedure based on the system information, send a message to the base station for requesting to send a discovery signal based on the SSB, and perform tracking for at least one of time and frequency based on the discovery signal.

[0020] As an example of the present disclosure, a base station in a wireless communication system may include a transceiver and a processor connected to the transceiver, and the processor may be configured to send at least one synchronization signal and a broadcast channel block (SSB), send system information related to a random access channel, perform a random access procedure based on the system information, receive a message for requesting the base station to send an SSB-based discovery signal, and send a discovery signal.

[0021] As an example of the present disclosure, a communication device may include at least one processor and at least one computer memory, wherein the at least one computer memory is connected to the at least one processor and stores instructions, wherein the instructions indicate operations when executed by the at least one processor, and the operations may include: receiving at least one synchronization signal and a broadcast channel block (SSB); obtaining synchronization with a base station by using a synchronization signal included in the SSB; obtaining system information based on a master information block (MIB) included in the SSB, performing a random access procedure based on the system information, sending a message to the base station for requesting to send an SSB-based discovery signal, and performing tracking for at least one of time and frequency based on the discovery signal.

[0022] As an example of the present disclosure, a non-transitory computer-readable medium storing at least one instruction may include at least one instruction capable of being executed by a processor, and the at least one instruction may control a device to receive at least one synchronization signal and a broadcast channel block (SSB), obtain synchronization with a base station by using the synchronization signal included in the SSB, obtain system information based on a master information block (MIB) included in the SSB, perform a random access procedure based on the system information, send a message to the base station for requesting to send a discovery signal based on the SSB, and perform tracking for at least one of time and frequency based on the discovery signal.

[0023] The above-mentioned aspects of the present disclosure are only a part of exemplary embodiments of the present disclosure, and those skilled in the art can derive and understand various embodiments reflecting the technical features of the present disclosure based on the following detailed description of the present disclosure.

[0024] Beneficial Effects

[0025] As is apparent from the above description, the embodiments of the present disclosure have the following effects.

[0026] According to the present disclosure, the energy consumption of a base station can be reduced.

[0027] Those skilled in the art will appreciate that the effects that can be achieved by the embodiments of the present disclosure are not limited to the above effects, and other beneficial effects of the present disclosure will be more clearly understood from the following detailed description. That is, those skilled in the art can derive unexpected effects according to the embodiments of the present disclosure from the embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are provided to help understand the present disclosure, and may provide embodiments of the present disclosure together with the detailed description. However, the technical features of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form new embodiments. The reference numerals in each drawing may refer to structural elements.

[0029] Figure 1 An example of a structure of a wireless communication system to which the present disclosure can be applied is illustrated.

[0030] Figure 2 An example of a wireless device applicable to the present disclosure is illustrated.

[0031] Figure 3 The frame structure in a wireless communication system to which the present disclosure can be applied is illustrated.

[0032] Figure 4 An example of a resource grid in a wireless communication system to which the present disclosure can be applied is illustrated.

[0033] Figure 5 An example of a physical resource block in a wireless communication system to which the present disclosure can be applied is illustrated.

[0034] Figure 6 An example of a time slot structure in a wireless communication system to which the present disclosure can be applied is illustrated.

[0035] Figure 7 An example of a physical channel used in a wireless communication system to which the present disclosure can be applied and an example of a general signal transmission and reception method using the physical channel are illustrated.

[0036] Figure 8 The structure of an SSB (synchronization signal and broadcast channel block) applicable to the present disclosure is illustrated.

[0037] Fig. 9 The transmission of SSB applicable to the present disclosure is illustrated.

[0038] Fig.10 Examples of SSB candidate positions applicable to the present disclosure are illustrated.

[0039] Fig.11 An example of downlink time synchronization information applicable to the present disclosure is illustrated.

[0040] Fig.12 An example of a method for notifying an actually transmitted SSB is illustrated.

[0041] Fig.13 An example of a TRS process applicable to the present disclosure is illustrated.

[0042] Fig.14 An example of the difference in distance between a terminal and a macro cell and a small cell in a carrier aggregation environment is illustrated.

[0043] Fig.15 An example of multiplexing of an SSB and a Tracking Reference Signal (TRS) in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0044] Fig.16 The SSB transmission timing for each case in the wireless communication system according to the embodiment of the present disclosure is illustrated.

[0045] Fig.17 An example of a process for signaling a structure of a cell discovery signal in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0046] Fig.18 An example of a guard carrier applicable to a synchronization signal in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0047] Fig.19 An example of a format of a synchronous random access channel (RACH) preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0048] Fig. 20 Other examples of the format of a synchronous RACH preamble in a wireless communication system according to an embodiment of the present disclosure are illustrated.

[0049] Fig.21 An example of a process for receiving a discovery signal in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0050] Fig. 22 An example of a process for transmitting a discovery signal in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0051] Fig.23 An example of a process for requesting and transmitting a discovery signal in a wireless communication system according to an embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0052] The embodiments of the present disclosure described below are combinations of elements and features of the present disclosure in a particular form. Unless otherwise mentioned, elements or features may be considered to be selective. Each element or feature may be put into practice without being combined with other elements or features. In addition, embodiments of the present disclosure may be constructed by combining some elements and / or features. The order of operations described in the embodiments of the present disclosure may be rearranged. Some structures or elements of any one embodiment may be included in another embodiment and may be replaced by the corresponding structures or features of another embodiment.

[0053] In the description of the drawings, processes or steps that render the scope of the present disclosure unnecessarily ambiguous will be omitted, and processes or steps that can be understood by those skilled in the art will be omitted.

[0054] Throughout the specification, when a part "includes" or "comprises" a component, this indicates that other components are not excluded and may further be included, unless otherwise specified. The terms "unit", "-or / er" and "module" described in this specification indicate a unit for processing at least one function or operation, which can be implemented by hardware, software or a combination thereof. In addition, "a" or "an", "one", "the", etc. in the context of the present disclosure (more specifically, in the context of the appended claims) may include singular and plural expressions, unless otherwise specified in the specification or unless the context clearly indicates otherwise.

[0055] In the embodiments of the present disclosure, the data transmission and reception relationship between the base station (BS) and the mobile station is mainly described. The BS refers to the terminal node of the network, which directly communicates with the mobile station. The specific operation described as being performed by the BS can be performed by the upper node of the BS.

[0056] That is, it is apparent that in a network composed of a plurality of network nodes including a BS, various operations performed for communication with a mobile station may be performed by the BS or network nodes other than the BS. The term "BS" may be replaced with a fixed station, a Node B, an evolved Node B (eNode B or eNB), an advanced base station (ABS), an access point, etc.

[0057] In an embodiment of the present disclosure, the term terminal may be replaced with UE, mobile station (MS), subscriber station (SS), mobile subscriber station (MSS), mobile terminal, advanced mobile station (AMS), etc.

[0058] The transmitter is a fixed and / or mobile node that provides data services or voice services, and the receiver is a fixed and / or mobile node that receives data services or voice services. Therefore, on the uplink (UL), the mobile station can act as a transmitter and the BS can act as a receiver. Similarly, on the downlink (DL), the mobile station can act as a receiver and the BS can act as a transmitter.

[0059] The embodiments of the present disclosure may be supported by at least one of the standard specifications disclosed for wireless access systems including the Institute of Electrical and Electronics Engineers (IEEE) 802.xx system, the 3rd Generation Partnership Project (3GPP) system, the 3GPP Long Term Evolution (LTE) system, the 3GPP Fifth Generation (5G) New Radio (NR) system, and the 3GPP2 system. Specifically, the embodiments of the present disclosure may be supported by the standard specifications 3GPP TS 36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS36.321, and 3GPP TS 36.331.

[0060] In addition, the embodiments of the present disclosure are applicable to other radio access systems and are not limited to the above-mentioned systems. For example, the embodiments of the present disclosure are applicable to systems applied after the 3GPP 5G NR system and are not limited to a specific system.

[0061] That is, steps or parts that are not described to clarify the technical features of the present disclosure may be supported by those documents. In addition, all terms as proposed herein may be interpreted by standard documents.

[0062] Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The detailed description given below with reference to the accompanying drawings is intended to explain exemplary embodiments of the present disclosure, rather than to show the only embodiments that can be implemented according to the present disclosure.

[0063] The following detailed description includes specific terms in order to provide a thorough understanding of the present disclosure. However, it is obvious to those skilled in the art that other terms may be used to replace specific terms without departing from the technical spirit and scope of the present disclosure.

[0064] The embodiments of the present disclosure can be applied to various radio access systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), etc.

[0065] Hereinafter, in order to clarify the following description, the description is based on the 3GPP communication system (e.g., LTE, NR, etc.), but the technical spirit of the present disclosure is not limited thereto. LTE may refer to the technology after 3GPP TS 36.xxx version 8. Specifically, the LTE technology after 3GPP TS 36.xxx version 10 may be referred to as LTE-A, and the LTE technology after 3GPP TS 36.xxx version 13 may be referred to as pre-LTE-A. 3GPP NR may refer to the technology after TS 38.xxx version 15. 3GPP 6G may refer to the technology after TS version 17 and / or version 18. "xxx" may refer to the detailed number of the standard document. LTE / NR / 6G may be collectively referred to as the 3GPP system.

[0066] 3GPP 6G may refer to post-3GPP NR technology based on the 3GPP system. 3GPP 6G may not be limited to a version or a specific TS document, and its name may have a different form from 3GPP 6G. That is, 3GPP 6G may refer to a technology introduced after 3GPP NR, and is not limited to a specific form.

[0067] The following description will mainly focus on the 3GPP NR system, but is not limited thereto, and can be applied to 3GPP 6G. In addition, the content described below may be partially modified to be used in consideration of the 3GPP 6G system, and is not limited to a specific form. However, in the following, for ease of explanation, the 3GPP NR system will be mainly described. For the background technology, terms, abbreviations, etc. used in this disclosure, please refer to the matters described in the standard documents published before this disclosure. For example, standard documents 36.xxx and 38.xxx may be referenced.

[0068] Overall system

[0069] As more and more communication devices require greater communication capacity, the demand for mobile broadband communications that are more enhanced than existing radio access technologies (RATs) is rising. In addition, large-scale machine type communications (MTC) that provide various services anytime and anywhere by connecting multiple devices and things is also one of the main issues worth considering in next-generation communications. In addition, the design of communication systems that consider services / terminals that are sensitive to reliability and latency is also under discussion. Therefore, the introduction of next-generation RATs that consider enhanced mobile broadband communications (eMBB), massive MTC (mMTC), ultra-reliable low-latency communications (URLLC), etc. is under discussion, and for convenience, the corresponding technology is referred to as NR in this disclosure. NR is an expression representing an example of 5G RAT.

[0070] The new RAT system including NR uses an OFDM transmission method or a similar transmission method. The new RAT system may follow OFDM parameters different from those of LTE. Alternatively, the new RAT system may follow the parameter set of the existing LTE / LTE-A as is, but support a wider system bandwidth (e.g., 100MHz). Alternatively, a cell may support multiple parameter sets. In other words, terminals operating according to different parameter sets may coexist in one cell.

[0071] A parameter set corresponds to one subcarrier spacing in the frequency domain. Because the reference subcarrier spacing is scaled by an integer N, different parameter sets can be defined.

[0072] In addition, new RAT systems including 6G may be considered as next generation RATs. New RAT systems including 6G may consider i) very high data speeds per device, ii) a large number of connected devices, iii) global connectivity, iv) very low latency, v) reduced energy consumption of battery-free IoT devices, vi) ultra-high reliability connectivity, and vii) connectivity intelligence with machine learning capabilities, but are not limited thereto. In view of the above, new RAT systems including 6G may consider using the terahertz (THz) band, i.e., a frequency higher than the NR system, for wider bandwidth and higher transmission speeds. RAT systems including 6G may overcome existing limitations by applying artificial intelligence / machine learning (AI / ML), but may not be limited thereto.

[0073] Figure 1 The structure of a wireless communication system to which the present disclosure can be applied is illustrated. Figure 1 , NG-RAN consists of gNBs that provide control plane (RRC) protocol terminations for the NG-Radio Access (NG-RA) user plane (i.e., new access stratum (AS) sublayer / packet data convergence protocol (PDCP) / radio link control (RLC) / MAC / PHY) and UE. The gNBs are interconnected through the Xn interface. In addition, the gNBs are connected to the new generation core (NGC) through the N2 interface. More specifically, the gNB is connected to the access and mobility management function (AMF) through the N2 interface and to the user plane function (UPF) through the N3 interface. Figure 1 It can be based on the structure of the NR system. Figure 1 The structure can be used in the 6G system as it is or by being partially modified, and is not limited to a specific form.

[0074] Figure 2 An example of a wireless device applicable to the present disclosure is illustrated.

[0075] Reference Figure 2The wireless device 200 may send / receive radio signals via various wireless access technologies (e.g., LTE, LTE-A, pre-LTE-A, NR, 5G, 5G-A, 6G). The wireless device 200 may include at least one processor 202 and at least one memory 204, and may further include at least one transceiver 206 and / or at least one antenna 208.

[0076] The processor 202 may be configured to control the memory 204 and / or the transceiver 206 and implement the description, function, process, proposal, method and / or operation flow chart disclosed in this document. For example, the processor 202 may generate a first information / signal by processing the information in the memory 204, and then send a radio signal including the first information / signal through the transceiver 206. In addition, the processor 202 may receive a radio signal including a second information / signal through the transceiver 206, and then store information obtained from the signal processing of the second information / signal in the memory 204. The memory 204 may be connected to the processor 202 and store various information associated with the operation of the processor 202. For example, the memory 204 may store software code including instructions for implementing part or all of the processes controlled by the processor 202 or for implementing the description, function, process, proposal, method and / or operation flow chart disclosed in this document. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless communication technology. The transceiver 206 may be connected to the processor 202 and transmit and / or receive radio signals through at least one antenna 208. The transceiver 206 may be a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with a radio frequency (RF) unit. In the present disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0077] Hereinafter, the hardware elements of the wireless device 200 will be described in further detail. Although not limited thereto, at least one processor 202 may implement at least one protocol layer (e.g., functional layers such as physical (PHY), medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), radio resource control (RRC), and service data adaptation protocol (SDAP)). At least one processor 202 may generate at least one protocol data unit (PDU) and / or at least one service data unit (SDU) according to the description, function, process, proposal, method, and / or operation flow chart disclosed in this document. At least one processor 202 may generate a message, control information, data, or information according to the description, function, process, proposal, method, and / or operation flow chart disclosed in this document. At least one processor 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the function, process, proposal, and / or method disclosed in this document, and provide the signal to at least one transceiver 206. At least one processor 202 can receive a signal (e.g., a baseband signal) from at least one transceiver 206 and obtain PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in this document.

[0078] At least one processor 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. At least one processor 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, at least one application specific integrated circuit (ASIC), at least one digital signal processor (DSP), at least one digital signal processing device (DSPD), at least one programmable logic device (PLD), or at least one field programmable gate array (FPGA) may be included in at least one processor 202. The description, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, or functions. Firmware or software configured to execute the description, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be included in at least one processor 202, or may be stored in at least one memory 204 and executed by at least one processor 202. The description, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or instruction sets.

[0079] At least one memory 204 may be connected to at least one processor 202 and store various forms of data, signals, messages, information, programs, codes, instructions, and / or instructions. At least one memory 204 may be configured as a read-only memory (ROM), a random access memory (RAM), an erasable programmable read-only memory (EPROM), a flash memory, a hard disk, a register, a cache memory, a computer-readable storage medium, and / or a combination thereof. At least one memory 204 may be located inside and / or outside of at least one processor 202. In addition, at least one memory 204 may be connected to at least one processor 202 via various technologies such as a wired or wireless connection.

[0080] At least one transceiver 206 can send user data, control information, and wireless signals / channels mentioned in the method and / or operation flow chart of this document to at least one other device. At least one transceiver 206 can receive user data, control information, and wireless signals / channels mentioned in the description, function, process, proposal, method, and / or operation flow chart disclosed in this document from at least one other device. For example, at least one transceiver 206 can be connected to at least one processor 202 and send and receive radio signals. For example, at least one processor 202 can control at least one transceiver 206 to send user data, control information, or radio signals to at least one other device. In addition, at least one processor 202 can control at least one transceiver 206 to receive user data, control information, or radio signals from at least one other device. In addition, at least one transceiver 206 can be connected to at least one antenna 208, and at least one transceiver 206 can be configured to send and receive user data, control information, and radio signals / channels mentioned in the description, function, process, proposal, method, and / or operation flow chart disclosed in this document through at least one antenna 208. In this document, at least one antenna may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). At least one transceiver 206 may convert received radio signals / channels from RF band signals to baseband signals in order to facilitate processing of received user data, control information, and radio signals / channels using at least one processor 202. At least one transceiver 206 may convert user data, control information, and radio signals / channels processed using at least one processor 202 from baseband signals to RF band signals. To this end, at least one transceiver 206 may include an (analog) oscillator and / or a filter.

[0081] Reference Figure 2The components of the described wireless device may be referred to by other terms from the functional aspect. For example, the processor 202 may be referred to as a control unit, the transceiver 206 may be referred to as a communication unit, and the memory 204 may be referred to as a storage unit. In some cases, the communication unit may be used to mean at least a part of the processor 202 and the transceiver 206.

[0082] Reference Figure 2 The structure of the wireless device described may be understood as the structure of at least a portion of various devices. As an example, the structure may be at least a portion of various devices (e.g., a robot, a vehicle, an XR device, a handheld device, a home appliance, an IoT device, an AI device / server, etc.). In addition, according to various embodiments, in addition to Figure 2 In addition to the components illustrated in the figure, the device may further include other components.

[0083] For example, the device may be a handheld device such as a smart phone, a smart tablet, a wearable device (e.g., a smart watch, smart glasses), and a handheld computer (e.g., a laptop computer, etc.). In this case, the device may further include at least one of: a power supply unit that supplies power and includes a wired / wireless charging circuit, a battery, etc.; an interface unit that includes at least one port for connecting to another device (e.g., an audio input / output port, a video input / output port); and an input / output unit for inputting and outputting video information / signals, audio information / signals, data, and / or information input from a user.

[0084] For example, the device may be a mobile device such as a mobile robot, a vehicle, a train, a manned / unmanned aerial vehicle (AV), and a ship. In this case, the device may further include at least one of the following: a drive unit including at least one of an engine, a motor, a power train, wheels, brakes, and a steering device of the device; a power supply unit that supplies power and includes a wired / wireless charging circuit, a battery, etc.; a sensor unit that senses state information, environmental information, and user information of the device or the surroundings of the device; an automatic driving unit that performs functions such as route maintenance, speed control, and destination setting; and a position measurement unit that obtains mobile object position information through a global positioning system (GPS) and various sensors.

[0085] For example, the device may be an XR device such as an HMD, a head-up display (HUD) provided in a vehicle, a TV, a smartphone, a wearable device, a home appliance device, a digital signage, a vehicle, and a robot. In this case, the device may further include at least one of: a power supply unit that supplies power and includes a wired / wireless charging circuit, a battery, etc.; an input / output unit that obtains control information and data from the outside and outputs a generated XR object; and a sensor unit that senses state information, environmental information, and user information of the device or the surroundings of the device.

[0086] For example, the device may be a robot, which may be classified according to the purpose or field of use as industrial use, medical use, home use, military use, etc. In this case, the device may further include at least one of: a sensor unit that senses state information, environmental information, and user information of the device or the surroundings of the device; and a drive unit that moves robot joints and performs various other physical operations.

[0087] For example, the device may be an AI device such as a TV, a projector, a smartphone, a PC, a laptop, a digital broadcast terminal, a tablet, a wearable device, a set-top box (STB), a radio, a washing machine, a refrigerator, a digital signage, a robot, and a vehicle. In this case, the device may further include at least one of: an input unit that obtains various types of data from the outside; an output unit that generates an output associated with vision, hearing, or touch; a sensor unit that senses state information, environmental information, and user information of the device or the surroundings of the device; and a training unit that uses learning data to learn a model composed of an artificial neural network. Figure 2 The structure of the wireless device illustrated in the example can be understood as a part of a RAN node (eg, a base station, a DU, a RU, a RRH, etc.). That is, Figure 2 The device illustrated in the example may be a RAN node. In this case, the device may further include a wired transceiver for fronthaul and / or backhaul communication. However, in the case where the fronthaul and / or backhaul communication is based on wireless communication, Figure 2 The at least one transceiver 206 illustrated in FIG. 2 may be used for fronthaul and / or backhaul communications and may not include a wired transceiver.

[0088] Figure 3 The frame structure in a wireless communication system to which the present disclosure can be applied is illustrated.

[0089] The NR system may support multiple parameter sets. Here, the parameter set may be defined by a subcarrier spacing and a cyclic prefix (CP) overhead. Here, multiple subcarrier spacings may be derived by scaling the default (reference) subcarrier spacing by an integer N (or μ). In addition, although it is assumed that very low subcarrier spacing is not used in very high carrier frequencies, the parameter set used herein may be selected independently of the frequency band. In addition, various frame structures according to multiple parameter sets may be supported in the NR system.

[0090] In the following, OFDM parameter sets and frame structures that can be considered in the NR system will be described. The various OFDM parameter sets supported in the NR system can be defined as shown in Table 1 below.

[0091] [Table 1]

[0092] μ <![CDATA[Δf=2 μ ·15[kHz]]]> CP 0 15 normal 1 30 normal 2 60 Normal, Extended 3 120 normal 4 240 normal

[0093] NR supports multiple parameter sets (or subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15kHz, a wide area of ​​the traditional cellular band is supported, and when the SCS is 30kHz / 60kHz, dense urban areas, lower latency and wider carrier bandwidth are supported, and when the SCS is 60kHz or higher, bandwidth greater than 24.25GHz is supported to overcome phase noise.

[0094] The NR frequency band is defined as two types of frequency ranges (FR1, FR2). FR1 and FR2 can be configured as shown in Table 2 below. In addition, FR2 may mean millimeter wave (mmW).

[0095] [Table 2]

[0096] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 410MHz-7125MHz 15, 30, 60kHz FR2 24250MHz-52600MHz 60, 120, 240kHz

[0097] Regarding the frame structure in the NR system, the sizes of various fields in the time domain are expressed in T c =1 / (Δf max ·N f ) is expressed in multiples of the time unit. Here, Δf max 480·10 3 Hz, and N f is 4096. Downlink and uplink transmissions are configured (organized) with T f =1 / (Δf max ·N f / 100)T c =10 ms duration. Here, the radio frames are respectively configured with T sf =(Δf max ·N f / 1000)T c=10 subframes of duration of 1ms. In this case, there is one set of frames for uplink and one set of subframes for downlink. In addition, the transmission in uplink frame number i from the terminal should start T earlier than the corresponding downlink frame in the corresponding terminal. TA =(N TA +N TA，offset )T c For the subcarrier spacing configuration μ, the time slots in the subframe are The time slots in a radio frame are numbered in ascending order of A time slot is configured with A continuous OFDM symbol configuration is determined based on the CP Time slot in subframe The start time is the same as the OFDM symbol in the same subframe It is impossible for all terminals to perform transmission and reception at the same time, which means that not all OFDM symbols of a downlink time slot or an uplink time slot are available.

[0098] Table 3 shows the number of OFDM symbols per time slot in a normal CP Number of time slots per radio frame and the number of time slots per subframe And Table 4 represents the number of OFDM symbols per slot, the number of slots per radio frame, and the number of slots per subframe in the extended CP.

[0099] [Table 3]

[0100]

[0101] [Table 4]

[0102]

[0103] Figure 3 This is an example about μ=2 (SCS is 60 kHz), and referring to Table 3, 1 subframe may include 4 slots. Figure 3 1 subframe = {1, 2, 4} slots shown in is an example, and the number of slots that may be included in 1 subframe is as defined in Table 3 or Table 4. In addition, a mini-slot may include 2, 4, or 7 symbols or more or less.

[0104] Regarding the physical resources in the NR system, antenna ports, resource grids, resource elements, resource blocks, carrier parts, etc. can be considered. Hereinafter, the physical resources that can be considered in the NR system will be described in detail.

[0105] First, with respect to antenna ports, the antenna ports are defined so that the channel carrying the symbol in the antenna port can be inferred from the channel carrying another symbol in the same antenna port. When the large-scale characteristics of the channel carrying the symbol in one antenna port can be inferred from the channel carrying the symbol in another antenna port, the two antenna ports can be said to be in a quasi-co-location or quasi-co-location (QC / QCL) relationship. In this case, the large-scale characteristics include one or more of delay spread, Doppler spread, frequency offset, average received power, and receive timing.

[0106] In the 6G system, communication can be performed at the above-mentioned THz frequency band higher than the millimeter wave (mmW) frequency, and the same Figure 3 The same frame structure as shown, or a separate frame structure for the 6G system may be used, but is not limited to a specific form.

[0107] Figure 4 A resource grid in a wireless communication system to which the present disclosure can be applied is illustrated.

[0108] Reference Figure 4 , as an illustrative description, the resource grid is configured in the frequency domain with subcarriers, and one subframe is configured with 14·2 μ OFDM symbols, but the resource grid and subframe are not limited to this. In the NR system, the transmitted signal consists of OFDM symbols and One or more resource grids for each subcarrier. represents the maximum transmission bandwidth, which may differ between uplink and downlink and between parameter sets. In this case, one resource grid can be configured for each μ and antenna port p. Each element of the resource grid for μ and antenna port p is called a resource element and is uniquely identified by an index pair (k, l'). Here, k = 0, ..., is an index in the frequency domain, and l'=0,..., refers to the position of a symbol in a subframe. When referring to a resource element in a slot, an index pair (k, l) is used. Here, l = 0, ..., The resource element (k, l') for μ and antenna port p corresponds to the complex value When there is no risk of confusion or no specific antenna port or parameter set is specified, the indices p and μ can be discarded and the complex value can be or a k，l′ In addition, a resource block (RB) is defined as consecutive subcarriers.

[0109] Point A plays the role of a common reference point for the resource block grid and is obtained as follows.

[0110] -OffsetToPointA for the primary cell (PCell) downlink represents the frequency offset between point A and the lowest subcarrier of the lowest resource block overlapping with the SS / PBCH block used by the terminal for initial cell selection. It is expressed in resource blocks, assuming that the subcarrier spacing for FR1 is 15kHz and the subcarrier spacing for FR2 is 60kHz.

[0111] absoluteFrequencyPointA represents the frequency position of point A, as expressed in terms of an absolute radio frequency channel number (ARFCN).

[0112] For subcarrier spacing configuration μ, the common resource blocks are numbered from 0 upwards in the frequency domain. The center of subcarrier 0 of common resource block 0 for subcarrier spacing configuration μ is the same as "point A". Number of common resource blocks for subcarrier spacing configuration μ in the frequency domain The relationship between and resource element (k, l) is given by the following formula 1.

[0113] [Formula 1]

[0114]

[0115] In equation 1, k is defined relative to point A, so that k=0 corresponds to a subcarrier centered at point A. Physical resource blocks are spaced from 0 to 1 in a bandwidth part (BWP). where i is the number of the BWP. Physical resource block n in BWP i PRB and public resource block n CRB The relationship between is given by the following formula 2.

[0116] [Formula 2]

[0117]

[0118] is the common resource block where the BWP starts relative to common resource block 0.

[0119] Figure 5 The physical resource blocks in the wireless communication system to which the present disclosure can be applied are illustrated. Figure 6 The following illustrates a time slot structure in a wireless communication system to which the present disclosure can be applied.

[0120] Reference Figure 5 and Figure 6 , a slot includes a plurality of symbols in the time domain. For example, for a normal CP, a slot includes 7 symbols, but for an extended CP, a slot includes 6 symbols.

[0121] A carrier includes multiple subcarriers in the frequency domain. A resource block (RB) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) is defined as multiple consecutive (physical) resource blocks in the frequency domain and may correspond to a parameter set (e.g., SCS, CP length, etc.). A carrier may include up to N (e.g., 5) BWPs. Data communication may be performed through an activated BWP, and only one BWP may be activated for one terminal. In a resource grid, each element is called a resource element (RE) and may map a complex symbol.

[0122] In the NR system, each component carrier (CC) can support up to 400MHz. If the terminal working in such a wideband CC always operates with the radio frequency (FR) chip for the entire CC turned on, the terminal battery consumption may increase. Alternatively, when considering several application scenarios operating in a wideband CC (e.g., eMBB, URLLC, Mmtc, V2X, etc.), different parameter sets (e.g., subcarrier spacing, etc.) can be supported in each frequency band in the corresponding CC. Alternatively, each terminal may have a different maximum bandwidth capability. In this regard, the base station may instruct the terminal to operate only in part of the bandwidth instead of the total bandwidth of the wideband CC, and for convenience, the corresponding part of the bandwidth is defined as a bandwidth part (BWP). BWP can be configured with continuous RBs on the frequency axis and may correspond to a parameter set (e.g., subcarrier spacing, CP length, slot / microslot duration).

[0123] At the same time, even in one CC configured for the terminal, the base station can configure multiple BWPs. For example, a BWP occupying a relatively small frequency domain can be configured in the PDCCH monitoring time slot, and the PDSCH indicated by the PDCCH can be scheduled in a larger BWP. Alternatively, when the UE is congested in a specific BWP, some terminals can be configured with another BWP for load balancing. Alternatively, considering the frequency domain inter-cell interference elimination between adjacent cells, etc., some middle spectrums of the entire bandwidth can be excluded, and the BWPs on two edges can be configured in the same time slot. In other words, the base station can configure at least one DL / UL BWP for a terminal associated with a broadband CC. The base station can activate at least one DL / UL BWP in the configured DL / UL BWP at a specific time (through L1 signaling or MAC control unit (CE) or RRC signaling, etc.). In addition, the base station can indicate switching to another configured DL / UL BWP (through L1 signaling or MAC CE or RRC signaling, etc.). Alternatively, based on a timer, when the timer value expires, it can switch to the determined DL / UL BWP. Here, the activated DL / UL BWP is defined as the active DL / UL BWP. However, when the terminal performs the initial access process or has not yet established an RRC connection, the configuration of the DL / UL BWP may not be received, so the DL / UL BWP assumed by the terminal in this case is defined as the initial active DL / UL BWP.

[0124] Figure 7 Physical channels used in a wireless communication system to which the present disclosure can be applied and a general signal transmission and reception method using the physical channels are illustrated.

[0125] In a wireless communication system, a terminal receives information from a base station via a downlink, and a terminal sends information to a base station via an uplink. The information sent and received by the base station and the terminal includes data and various control information, and there are various physical channels according to the type / purpose of the information they send and receive.

[0126] When the terminal is turned on or newly enters a cell, the terminal performs an initial cell search, which includes synchronization with a base station (S701). To this end, the terminal can synchronize with the base station by receiving a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station, and obtain information such as a cell identifier (ID). Next, the terminal can obtain broadcast information in the cell by receiving a physical broadcast channel (PBCH) from the base station. At the same time, the terminal can check the downlink channel state by receiving a downlink reference signal (DL RS) in the initial cell search step.

[0127] The terminal that has completed the initial cell search can obtain more detailed system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) according to information carried in the PDCCH (S702).

[0128] Meanwhile, if the terminal accesses the base station for the first time or does not have radio resources for signal transmission, the terminal may perform a random access procedure (RACH) on the base station (S703 to S706). To this end, the terminal may send a specific sequence as a preamble through a physical random access channel (PRACH) (S703 and S705), and receive a response message to the preamble through a PDCCH and a corresponding PDSCH (S704 and S706). In the case of a contention-based RACH, a contention resolution process may be additionally performed.

[0129] The terminal having performed the above process may then perform PDCCH / PDSCH reception (S707) and physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) transmission (S708) as a general uplink / downlink signal transmission process. Specifically, the terminal receives downlink control information (DCI) through PDCCH. Here, DCI includes control information such as resource allocation information for the terminal, and has different formats depending on its purpose of use.

[0130] At the same time, the control information sent by the terminal to the base station through the uplink or received by the terminal from the base station includes downlink / uplink confirmation / non-confirmation (ACK / NACK) signal, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), etc. For the 3GPP LTE system, the terminal can send the above-mentioned CQI / PMI / RI and other control information through PUSCH and / or PUCCH.

[0131] SSB (Synchronization Signal Block) transmission and related operations

[0132] Figure 8 The structure of an SSB (synchronization signal and broadcast channel block) applicable to the present disclosure is illustrated. Figure 8 The SSB structure is illustrated. The terminal can perform cell search, system information acquisition, beam alignment for initial access, DL measurement, etc. based on the SSB. The SSB is used interchangeably with the SS / PBCH (Synchronization Signal / Physical Broadcast Channel) block.

[0133] Reference Figure 8, SSB consists of PSS, SSS and PBCH. SSB consists of 4 consecutive OFDM symbols, and PSS, PBCH, SSS / PBCH and PBCH are sent for each OFDM symbol. PSS and SSS each consist of 1 OFDM symbol and 127 subcarriers, and PBCH consists of 3 OFDM symbols and 576 subcarriers. Polarization coding and QPSK (quadrature phase shift keying) are applied to PBCH. PBCH consists of data RE and DMRS (demodulation reference signal) RE for each OFDM symbol. Each RB has 3 DMRS REs, and there are 3 data REs between DMRS REs.

[0134] Community Search

[0135] Cell search refers to the process by which a terminal acquires time / frequency synchronization of a cell and detects the cell ID (identifier) ​​of the cell (e.g., physical layer cell ID, PCID). PSS is used to detect a cell ID within a cell ID group, and SSS is used to detect a cell ID group. PBCH is used for SSB (time) index detection and half-frame detection.

[0136] The cell search process of the terminal can be summarized as shown in the following [Table 5].

[0137] [Table 5]

[0138]

[0139] There are 336 cell ID groups, and each cell ID group has 3 cell IDs. There are 1008 cell IDs in total, and the cell ID can be defined by [Formula 3].

[0140] [Formula 3]

[0141] in, and

[0142] in, represents the cell ID (e.g., PCID), represents a cell ID group and is provided / obtained through SSS,

[0143] Indicates a cell ID within a cell ID group and is provided / obtained through the PSS.

[0144] PSS sequence d PSS (n) can be defined as satisfying [Equation 4].

[0145] [Formula 4]

[0146] d PSS(n) = 1-2x(m)

[0147]

[0148] Where 0≤n<127, x(i+7)=(x(i+4)+x(i)mod 2, and

[0149] [x(6) x(5) x(4) x(3) x(2) x(1) x(0)=[1 1 1 0 1 1 0].

[0150] SSS sequence d SSS (n) can be defined as satisfying [Equation 5].

[0151] [Formula 5]

[0152] d SSS (n)=[-2x0((n+m0)mod 127)][1-2x1((n+m1)mod 127)]

[0153]

[0154] Among them, 0≤n<127, x0(i+7)=(x0(i+4)+x0(i))mod2, x1(i+7)=(x1(i+1)+x1(i))mod2, [x0(6) x0(5) x0(4) x0(3) x0(2) x0(1) x(0)]=[0 0 0 0 0 0 1] and [x1(6) x1(5)x1(4) x1(3) x1(2) x1(1) x1(0)]=[0 0 0 0 0 0 1].

[0155] Fig. 9 The transmission of SSB applicable to the present disclosure is illustrated. The SSB is transmitted periodically according to the SSB period. The SSB basic period assumed by the terminal during the initial cell search is defined as 20ms. After cell access, the network (e.g., base station) can set the SSB to one of {5ms, 10ms, 20ms, 40ms, 80ms, 160ms}. The SSB burst set is configured at the beginning of the SSB period. The SSB burst set consists of a 5ms time window (i.e., half a frame), and the SSB can be transmitted up to L times within the SSB burst set. Depending on the frequency band of the carrier, the maximum number L of SSB transmissions can be given as follows. A time slot includes at most two SSBs.

[0156] - For the frequency range up to 3 GHz, L = 4

[0157] - For the frequency range of 3 GHz to 6 GHz, L = 8

[0158] - For the frequency range of 6 GHz to 52.6 GHz, L = 64

[0159] The temporal position of a candidate SSB within an SSB burst set may be defined according to the SCS as follows. The temporal position of a candidate SSB is indexed in temporal order from 0 to L-1 within an SSB burst set (ie, half-frame) (SSB index). Candidate SSB and SSB candidate may be used interchangeably in the specification.

[0160] - Case A - 15kHz SCS: The index of the starting symbol of the candidate SSB is given as {2,8}+14*n.

[0161] - For operation without shared spectrum channel access (eg, L-band, LCell): If the carrier frequency is 3 GHz or less, n = 0, 1. If the carrier frequency is 3 GHz to 6 GHz, n = 0, 1, 2, 3.

[0162] - For operation with shared spectrum channel access (eg, U-band, UCell): n=0, 1, 2, 3, 4.

[0163] - Case B - 30kHz SCS: The index of the starting symbol of the candidate SSB is given as {4,8,16,20}+28*n. If the carrier frequency is 3GHz or less, n=0. If the carrier frequency is 3GHz to 6GHz, n=0,1.

[0164] - Case C - 30kHz SCS: The index of the starting symbol of the candidate SSB is given as {2,8}+14*n.

[0165] - For operation without shared spectrum channel access: (1) For paired spectrum operation, when the carrier frequency is 3 GHz or less, n = 0, 1. When the carrier frequency is within FR1 and greater than 3 GHz, n = 0, 1, 2, 3. (2) For non-paired spectrum operation, when the carrier frequency is 2.4 GHz or less, n = 0, 1. When the carrier frequency is within FR1 and greater than 2.4 GHz, n = 0, 1, 2, 3.

[0166] - For operation without shared spectrum channel access: n=0, 1, 2, 3, 4, 6, 7, 8, 9.

[0167] - Case D - 120kHz SCS: The index of the starting symbol of the candidate SSB is given as {4,8,16,20}+28*n. For carrier frequencies in FR2, n=0,1,2,3,5,6,7,8,10,11,12,13,15,16,17,18.

[0168] - Case E - 240kHz SCS: The indices of the starting symbols of the candidate SSBs are given as {8, 12, 16, 20, 32, 36, 40, 44} + 56*n. For carrier frequencies within FR2, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0169] For operation with shared spectrum channel access, in the case of shared spectrum channel access operation, the terminal assumes that the SSB transmission within the half frame is within the discovery burst transmission window starting from the first symbol of the first time slot within the half frame. The discovery burst transmission window period for each serving cell may be provided to the terminal. If the discovery burst transmission window period is not provided, the terminal regards the discovery burst transmission window period as a half frame. For each serving cell, the terminal assumes that the repetition period of the discovery burst transmission window is the same as the repetition period of the half frame used for SSB reception. The terminal may assume that among the SSBs of the serving cell, the discovery burst transmission window has the same repetition period within the same discovery burst transmission window or across different discovery burst transmission windows. The SSB of the value is in a QCL (quasi co-location) relationship. represents the DM-RS sequence index of the PBCH of the SSB, and (i) provided by ssbPositionQCL-Relationship, or (ii) if ssbPositionQCL-Relationship is not provided, it can be obtained from the MIB (Master Information Block) of the SSB based on [Table 6].

[0170] [Table 6]

[0171]

[0172] ssbSubcarrierSpacingCommon represents the SCS of the RMSI used only for "operation without shared spectrum". The terminal assumes that the number of SSBs sent on the serving cell within the discovery burst transmission window is no greater than The terminal can be based on or to determine the SSB index. Here, i represents the candidate SSB index. Accordingly, more than one candidate SSB may correspond to one SSB index. Candidate SSBs corresponding to the same SSB index are quasi-co-located.

[0173] Fig.10 Examples of SSB candidate positions applicable to the present disclosure are illustrated. Fig.10The case where Q is 4 and ssb-PositionsInBurst is set to "10100000" is illustrated. In this case, only SSBs with SSB (SS / PBCH block) index #0 / #2 can be transmitted. ssb-PositionsInBurst and Q can be used to provide a rate matching mode within a DRS (discovery reference signal) transmission window (or discovery burst transmission window). For example, the terminal can perform rate matching for all SSB candidate position indices that are consistent with the actual transmitted SSB index QCL provided by ssb-PositionsInBurst. Fig.10 In the example, the terminal can perform rate matching on the time / frequency resources of SSB candidate position index 0 / 2 / 4 / 6 / 8 / 10 / 12 / 14 / 16 / 18. Therefore, when receiving a PDSCH scheduled by a PDCCH scrambled with CRC by C-RNTI, MCS-C-RNTI, CS-RNTI, RA-RNTI, MsbB-RNTI, P-RNTI, TC-RNTI (or a PDSCH with SPS (or with CRC) scrambled by SI-RNTI and the system information indicator (i.e., DCI) in the PDCCH is set to 1), if the PDSCH resource allocation overlaps with the PRB including the SSB transmission resources (e.g., SS / PBCH block candidate position index 0 / 2 / 4 / 6 / 8 / 10 / 12 / 14 / 16 / 18), the terminal can assume SSB transmission according to ssb-PositionsInBurst. That is, the terminal may assume that a PRB including SSB transmission resources in an OFDM symbol in which an SSB is transmitted is unavailable for a PDSCH (ie, not mapped).

[0174] Fig.11 An example of downlink time synchronization information applicable to the present disclosure is illustrated. Fig.11 The terminal obtains information about DL time synchronization. The terminal can obtain DL synchronization by detecting SSB. The terminal can identify the structure of the SSB burst set based on the detected SSB index, and can detect the symbol / time slot / half-frame boundary accordingly. The SFN information and half-frame indication information can be used to identify the number of frames / half-frames to which the detected SSB belongs.

[0175] Specifically, the terminal can obtain 10-bit SFN (system frame number) information (s0 to s9) from the PBCH. Among the 10-bit SFN information, 6 bits are obtained from the MIB (master information block) and the remaining 4 bits are obtained from the PBCH TB (transport block).

[0176] Next, the terminal can obtain 1 bit of half-frame indication information (c0). When the carrier frequency is 3 GHz or less, the half-frame indication information can be implicitly signaled using PBCH DMRS. PBCH DMRS indicates 3 bits of information by using one of 8 PBCH DMRS sequences. Therefore, in the case of L=4, among the 3 bits that can be indicated using 8 PBCH DMRS sequences, the remaining 1 bit after indicating the SSB index can be used to indicate the half-frame.

[0177] Finally, the terminal can obtain the SSB index based on the DMRS sequence and the PBCH payload. The SSB candidates are indexed in time order from 0 to L-1 within the SSB burst set (i.e., half-frame). When L=8 or 64, 8 different PBCH DMRS sequences can be used to indicate the 3 bits (b0 to b2) of the least significant bit (LSB) of the SSB index. When L=64, the 3 bits (b3 to b5) of the most significant bit (MSB) of the SSB index are indicated via PBCH. When L=2, 4 different PBCH DMRS sequences can be used to indicate the 2 bits (b0, b1) of the LSB of the SSB index. When L=4, among the 3 bits that can be indicated using 8 PBCH DMRS sequences, the remaining 1 bit after indicating the SSB index can be used to indicate the half frame (b2).

[0178] Fig.12 An example of a method for notifying an actually transmitted SSB is illustrated.

[0179] A maximum of L SSBs can be sent within one SSB burst set, and the number / position of SSBs actually sent can vary according to each base station / cell. The number / position of SSBs actually sent is used for rate matching and measurement, and information about the SSBs actually sent (e.g., ssb-PositionsInBurst) is indicated as follows.

[0180] -Regarding rate matching: This information can be indicated by terminal-specific RRC signaling or RMSI. In both frequency ranges below 6 GHz and above 6 GHz, the terminal-specific RRC signaling includes a complete bitmap (e.g., length L). On the other hand, as shown in the figure, the RMSI includes a complete bitmap below 6 GHz and a compressed form of the bitmap above 6 GHz. Specifically, information about the actually transmitted SSB can be indicated by using a group bitmap (8 bits) + an intra-group bitmap (8 bits). Here, the resources (e.g., REs) indicated by terminal-specific RRC signaling or RMSI can be reserved for SSB transmission, and rate matching can be performed on the PDSCH / PUSCH by considering the SSB resources.

[0181] - About measurement: In RRC connected mode, the network (e.g., base station) may include a set of SSBs to be measured during the measurement period. The SSB set may be indicated per frequency layer. In the absence of an indication of an SSB set, a default SSB set is used. The default SSB set includes all SSBs during the measurement period. The SSB set may be indicated by using a full bitmap (e.g., of length L) using RRC signaling. In RRC idle mode, the default SSB set is used.

[0182] CSI-RS (or TRS) for tracking

[0183] For the functionality of the cell-specific reference signal (CRS) used for fine time and frequency tracking in the LTE system, NR defines a tracking reference signal (TRS). However, unlike the CRS of the LTE system, the TRS defined in NR is not based on an always-on approach. The TRS defined in NR enables the terminal to estimate timing offset, delay spread, frequency offset, and Doppler spread. TRS is supported both below 6 GHz (FR1) and above 6 GHz (FR2).

[0184] Periodic TRS is mandatory in both FR1 and FR2, and aperiodic TRS is optional in both FR1 and FR2. Fig.13 An example of a TRS process applicable to the present disclosure is illustrated. Fig.13 In step S1301, the terminal 1310 receives an NZP-CSI-RS-ResourceSet information element (IE) including a trs-Info parameter from the base station 1320. The trs-Info parameter is a parameter indicating whether all NZP-CSI-RS resources in a CSI-RS resource set have the same antenna port and is set in an NZP-CSI-RS resource set unit.

[0185] The CSI-RS resources in the CSI-RS resource set where the trs-Info parameter is set to "ON" are configured as 1-port CSI-RS resources. The periodic CSI-RS resources in the CSI-RS resource set where the trs-Info parameter is set to "ON" have the same period, bandwidth, and subcarrier position. In addition, the non-periodic CSI-RS resources in the CSI-RS resource set where the trs-Info parameter is set to "ON" have the same bandwidth, the same RB position, and the same number of CSI-RS resources. If a non-periodic TRS is configured, the QCL reference of the TRS should be associated with the periodic TRS, and the QCL type is "QCL-Type-A" and "QCL-TypeD". In step S1303, the terminal 1310 performs time and / or frequency tracking through the CSI-RS resources in the CSI-RS resource set where the trs-Info is set to "ON".

[0186] Specific embodiments of the present disclosure

[0187] Hereinafter, the present disclosure is to operate a cell discovery signal in a wireless communication system, and propose a structure of the cell discovery signal and a technology for transmitting and receiving the cell discovery signal of the proposed structure.

[0188] Fig.14 An example of the difference in distance between a terminal and a macro cell and a small cell in a carrier aggregation environment is illustrated. Fig.14 , in a carrier aggregation (CA) environment (e.g., a combination of 15kHz SCS Scell ​​in FR1+120kHz SCS Scell ​​in FR2) for a macro cell 1410 and a small cell 1420, when the difference between the distance between the terminal and the macro cell and the distance between the terminal and the small cell is about 175m or more, the propagation delay may be greater than a 20kHz SCS CP length (=about 586 nanoseconds). Here, the macro cell may include at least one of a primary cell (Pcell) or a primary secondary cell (PScell), and the small cell may include a secondary cell.

[0189] In this carrier aggregation situation, it may happen that the difference in signal reception timing between the primary cell and the secondary cell is greater than the CP length based on the SCS of the secondary cell. Therefore, it is necessary to send a signal on the secondary cell to compensate for this.

[0190] The existing NR system allows the terminal to receive SSB (SS (Synchronization Signal) / PBCH (Physical Broadcast Channel) Block) and / or TRS (Tracking Reference Signal) on the secondary cell to obtain fine time / frequency synchronization of the secondary cell in preparation for the above situation. Figure 1 As shown, in the case of carrier aggregation of FR1 service cell and FR2 service cell, the terminal may include separate RF chains and frequency oscillators for FR1 and FR2. In this case, the terminal obtains coarse time / frequency axis synchronization by utilizing at least one of the primary synchronization signal (PSS), the secondary synchronization signal (SSS) or the PBCH DM-RS, and additionally obtains fine time / frequency axis synchronization by TRS, thereby minimizing the degree of time / frequency synchronization misalignment between the primary cell or the primary and secondary cells and the secondary cells.

[0191] However, when SSB and TRS are always transmitted on the secondary cell for the purpose of time / frequency synchronization as described above, power consumption may be high in terms of signal transmission of the base station and reception complexity of the terminal. In particular, since the base station should periodically transmit signals such as SSB and TRS even when there is no data to be sent or received, power consumption may occur. Recently, energy saving of base stations has been considered important in wireless communication systems including 3GPP because it can contribute to building an environmentally friendly network by reducing carbon emissions and reducing operating expenses (OPEX) of operators in the communication industry. Therefore, due to the increased interest in base station energy saving, a new SI (study item) called "Network Energy Saving Study" was approved in 3GPP NR Release 18.

[0192] Therefore, hereinafter, the present disclosure proposes a method for reconstructing the signals required for time / frequency synchronization acquisition as densely as possible on the time axis. Thus, by reducing the synchronization acquisition process of the terminal, the terminal implementation complexity and terminal power consumption can be reduced. In addition, the base station can save the energy consumed by sending the signal required for the synchronization acquisition of the terminal. In addition, the signal required for the time / frequency axis synchronization acquisition includes the cell ID information of the serving cell, so that a cell discovery function can be provided. hereinafter, in the present disclosure, the signal set sent by the base station for time / frequency synchronization acquisition of the serving cell may be referred to as ES-DRS (energy-saving discovery signal). In addition, hereinafter, the present disclosure proposes a method for configuring an ES-DRS signal and a method for signaling an ES-DRS signal.

[0193] According to various embodiments, the structure of the ES-DRS may be defined in various ways. For example, the ES-DRS may be defined in various ways according to the SSB-TRS multiplexing scheme, whether there is a PBCH, and whether the SSB is replaced. Hereinafter, some examples of the structure of the ES-DRS applicable to the present disclosure will be described. However, even if an ES-DRS having a different structure from the example structure described below is used, the embodiments described below will also apply.

[0194] [ES-DRS Structure Example #1] Method to configure ES-DRS using a single burst of TRS and SSB while preserving the structure of SSB

[0195] According to [ES-DRS structure example #1] of the present disclosure, the SSB structure of the existing NR system can be retained, and at least one TRS can be configured in the SSB symbol or the neighbor symbol of the SSB. Even if the SSB sent in the secondary cell is sent in a frequency position that is not in the synchronization grid, a cell definition SSB (CD-SSB) needs to be sent to support functions such as reading automatic neighbor relations (ANR) or cell global identification (CGI). CD-SSB refers to an SSB that provides configuration information for a monitoring opportunity, at which a PDCCH including scheduling information of a physical downlink shared channel (PDSCH) carrying SIB1 can be sent. Here, the monitoring opportunity may mean CORESET#0 and type0-PDCCH common search space (CSS) set. Therefore, it is necessary to provide PBCH information for the SSB sent in the secondary cell.

[0196] As described above, due to the frequency band difference between the primary cell and the secondary cell, if the terminal includes different RFs or different oscillators for the primary cell and the secondary cell, it is expected that the existing structure of both SSB and TRS is required. Therefore, the present disclosure proposes an ES-DRS structure in which the SSB structure is retained and TRS and SSB are configured as a single burst for transmission. When SSB and TRS are configured as a single burst, compared with separate transmission of SSB and TRS, the advantage is that the energy consumption of the base station is reduced.

[0197] [ES-DRS Structure Example #1-1] SSB and TRS constituting ES-DRS are multiplexed in the frequency domain and constituted as a single burst

[0198] In the NR system, SSB consists of 4 OFDM symbols.

[0199] Fig.15 An example of multiplexing of an SSB and a tracking reference signal (TRS) in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.15 Examples of SSB and TRS transmission structures are shown. Fig.15 , 4 OFDM symbols include symbol #n 1510, symbol #n+1 1520, symbol #n+2 1530, and symbol #n+3 1540. According to an embodiment, TRS 1512, 1514, 1542, and 1544 may be placed at both ends of the frequency axis of the SSB of 2 symbols among the 4 OFDM symbols 1510, 1520, 930, and 1540. Fig.15In the embodiment, TRS1512, 1514, 1542 and 1544 are placed at both ends of the frequency axis of symbol #n 1510 and symbol #n+3 1530. However, according to another embodiment, TRS1512, 1514, 1542 and 1544 may be placed at both ends of the frequency axis of symbol #n+1 1520 and symbol #n+3 1540, or at both ends of the frequency axis of symbol #n 910 and symbol #n+2 1530. Therefore, since a wider bandwidth TRS than SSB is provided, from the perspective of the terminal, the time axis synchronization accuracy can be improved compared with the time axis synchronization obtained only through the BBS.

[0200] The symbol spacing of the TRS may determine the accuracy of acquiring the frequency axis synchronization. Specifically, as the symbol spacing becomes larger, the accuracy may become higher. In this regard, in order to maximize the symbol spacing of the TRS multiplexed with the SSB frequency domain, the time axis placement of the TRS may preferably be as follows: Fig.15 Here, in a PSS symbol (e.g., symbol #n), the TRS may be placed in the same frequency region as symbol #n+3, as shown in FIG. Fig.15 As shown; or it can be mapped discontinuously on the frequency axis while clearing the 12 RBs occupied by the PSS.

[0201] [ES-DRS Structure Example #1-2] SSB and TRS constituting ES-DRS are multiplexed in the frequency domain / time domain and constituted as a single burst

[0202] The ES-DRS having the structure proposed in [Structure Example #1-1 of ES-DRS] can have a maximum spacing of 3 symbols between symbols where TRS is placed. On the other hand, in the NR system, TRS is basically defined to be transmitted at intervals of 4 symbols. Therefore, in order to provide the same level of frequency axis synchronization acquisition accuracy as TRS with a 4-symbol spacing, it is proposed that ES-DRS has a TDM / FDM structure between SSB and TRS.

[0203] The following [Table 7] illustrates a cell search procedure extracted from V17.2.0 of TS 38.213.

[0204] [Table 7]

[0205]

[0206]

[0207] In [Table 7], the transmission position of each SCS of SSB in the time slot (i.e., each case) can be as follows Fig.16 as shown in . Fig.16The SSB transmission timing for each case in the wireless communication system according to the embodiment of the present disclosure is illustrated. Fig.16 , the implementation of the ES-DRS configuration for each case will be described as follows.

[0208] - Case A or Case C 1610: For SSB #n, the corresponding TRS can be sent in symbols #1 and #5 or symbols #2 and #6, and for SSB #n+1, the corresponding TRS can be sent in symbols #7 and #11 or symbols #8 and #12. By doing so, the symbol interval between TRSs can be made the same as the symbol interval between TRSs in NR.

[0209] According to one embodiment, when TRS is transmitted in symbol #2 or symbol #8 which is a PSS symbol, 20 RBs occupied by PBCH or 12 RBs occupied by PSS in the symbol are cleared, and TRS may be discontinuously mapped on the frequency axis.

[0210] According to one embodiment, when TRS is transmitted in a symbol to which SSB is not mapped (e.g., symbol #1, symbol #6, symbol #7, or symbol #12), 20 RBs occupied by PBCH or 12 RBs occupied by PSS are cleared, and TRS may be mapped discontinuously on the frequency axis, or may be mapped continuously without gaps on the frequency axis.

[0211] According to one embodiment, when a TRS is transmitted in a PBCH symbol (eg, symbol #5 or symbol #11), 20 RBs occupied by the PBCH are emptied and the TRS may be discontinuously mapped on the frequency axis.

[0212] - Case B or Case D 1620: For SSB#n, the corresponding TRS may be transmitted in symbol#3 and symbol#7, for SSB#n+1, the corresponding TRS may be transmitted in symbol#8 and symbol#12, for SSB#n+2, the corresponding TRS may be transmitted in symbol#1 and symbol#5, and for SSB#n+3, the corresponding TRS may be transmitted in symbol#6 and symbol#10. By doing so, the symbol interval between TRSs may be made the same as the symbol interval between TRSs in NR.

[0213] According to one embodiment, when TRS is transmitted in a PSS symbol (e.g., symbol #8 for SSB #n+1 or symbol #6 for SSB #n+3), 20 RBs occupied by PBCH or 12 RBs occupied by PSS may be cleared and the TRS may be mapped discontinuously on the frequency axis.

[0214] According to one embodiment, when TRS is transmitted in a symbol to which SSB is not mapped (e.g., symbol #3 for SSB#n, symbol #12 for SSB#n+1, symbol #1 for SSB#n+2, or symbol #10 for SSB#n+3), 20 RBs occupied by PBCH or 12 RBs occupied by PSS are cleared, and TRS can be mapped discontinuously on the frequency axis or continuously without gaps on the frequency axis.

[0215] According to one embodiment, when TRS is transmitted in a PBCH symbol (eg, symbol #7 for SSB #n, symbol #5 for SSB #n+2), 20 RBs occupied by PBCH are cleared and TRS may be mapped discontinuously on the frequency axis.

[0216] - Case E 1630: Unlike other cases, in case E, since it is difficult to configure TRS for each SSB at an interval of 4 symbols, the transmission interval of TRS can be made to have an interval of 5 symbols. Specifically, for SSB#n, the corresponding TRS can be transmitted in symbols #6 and #11, for SSB#n+1, the corresponding TRS can be transmitted in symbols #7 and #12, for SSB#n+2, the corresponding TRS can be transmitted in symbols #5 and #10, and for SSB#n+3, the corresponding TRS can be transmitted in symbols #6 and #11. By doing so, the symbol interval between TRSs can be made the same as the symbol interval between TRSs in NR. Similarly, for SSB#n+4, the corresponding TRS may be transmitted in symbol #2 and symbol #7, for SSB#n+5, the corresponding TRS may be transmitted in symbol #3 and symbol #8, for SSB#n+6, the corresponding TRS may be transmitted in symbol #1 and symbol #6, and for SSB#n+7, the corresponding TRS may be transmitted in symbol #2 and symbol #7. In this way, the symbol interval between TRSs can be made the same as the symbol interval between TRSs in NR.

[0217] According to one embodiment, when TRS is transmitted in a PSS symbol (e.g., symbol #12 for SSB #n+1, symbol #6 for SSB #n+3, symbol #8 for SSB #n+5, or symbol #2 for SSB #n+7), 20 RBs occupied by PBCH or 12 RBs occupied by PSS are cleared and TRS can be mapped discontinuously on the frequency axis.

[0218] According to one embodiment, when TRS is transmitted in a symbol to which SSB is not mapped (e.g., symbol #6 for SSB#n, symbol #7 for SSB#n+1, symbol #10 for SSB#n+2, symbol #11 for SSB#n+3, symbol #2 for SSB#n+4, or symbol #3 for SSB#n+5, symbol #6 for SSB#n+6, symbol #7 for SSB#n+7), 20 RBs occupied by PBCH or 12 RBs occupied by PSS are cleared, and TRS can be mapped discontinuously on the frequency axis or continuously without gaps on the frequency axis.

[0219] According to one embodiment, when TRS is transmitted in a PBCH symbol (e.g., symbol #11 for SSB#n, symbol #5 for SSB#n+2, symbol #7 for SSB#n+4, symbol #1 for SSB#n+6), the 20 RBs occupied by the PBCH are cleared and the TRS can be mapped discontinuously on the frequency axis.

[0220] - Case F or Case G 1640: For SSB #n, the corresponding TRS can be transmitted in symbols #1 and #5 or symbols #2 and #6, and for SSB #n+1, the corresponding TRS can be transmitted in symbols #8 and #12 or symbols #9 and #13. By doing so, the symbol interval between TRSs can be made the same as the symbol interval between TRSs in NR.

[0221] According to one embodiment, when the TRS is transmitted in a PSS symbol (eg, symbol #2 or symbol #9), 20 RBs occupied by the PBCH or 12 RBs occupied by the PSS may be cleared and the TRS may be discontinuously mapped on the frequency axis.

[0222] According to one embodiment, when TRS is transmitted in a symbol to which SSB is not mapped (e.g., symbol #1, symbol #6, symbol #8, symbol #13), 20 RBs occupied by PBCH or 12 RBs occupied by PSS are cleared, and TRS can be mapped discontinuously on the frequency axis or continuously without gaps on the frequency axis.

[0223] According to one embodiment, when a TRS is transmitted in a PBCH symbol (eg, symbol #5 or symbol #12), 20 RBs occupied by the PBCH are emptied and the TRS may be discontinuously mapped on the frequency axis.

[0224] According to the ES-DRS proposed in [ES-DRS Structure Example #1-2], one of the two symbols constituting the TRS can be frequency domain multiplexed (FDM) with one of the four symbols constituting the associated SSB, and the other symbol can be time domain multiplexed (TDM) with the SSB.

[0225] In the above embodiment, the terminal may regard the TRS constituting the ES-DRS as having a QCL relationship with the associated SSB multiplexed and transmitted. Specifically, the TRS and SSB associated with each other may have a QCL relationship in attributes such as average gain, QCL-Type A and QCL-Type B.

[0226] [ES-DRS Structure Example #2] Method of modifying the existing SSB structure and configuring ES-DRS as a combination of downlink / uplink signals

[0227] Fig.17 The structure of SSB in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.17 The structure of SSB is illustrated, where PSS, PBCH, SSS and PBCH are placed on the time axis in sequence, PSS and SSS are respectively M sequences and Gold sequences of length 127 across 12 RBs, and PBCH is mapped across 20 RBs around SSS. In the case where the terminal receives SSB and performs the initial access process, according to the frequency range (FR) in which the terminal operates, the terminal can search for the synchronization grid that sends SSB and obtain system information through the SSB frequency position SSREF corresponding to the GSCN. The terminal obtains the symbol timing and the cell ID in the cell group from the PSS, and detects the cell group through the SSS. Next, the terminal can obtain the SSB index and the half-frame index (e.g., time slot and frame boundary detection) through the DMRS included in the PBCH, and decode the master information block (MIB) in the PBCH, thereby obtaining time information (e.g., 80ms, SFN, SSB index, superframe (HF)) and RMSI CORSET / search space (SS) configuration. Therefore, the terminal can perform time / frequency synchronization on the cell to be accessed through PSS, SSS and PBCH.

[0228] Fig.18 An example of a protection carrier applicable to a synchronization signal in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.18 As shown, the PSS and SSS, each consisting of a sequence of length 127, are mapped to PSS and SSS using 127 REs included in 12 RBs. In the 12 RBs, 17 subcarriers are reserved as guard carriers.

[0229] As described above, in a macro P(S)Cell-small Scell ​​CA environment, if the difference between the distance from the terminal to the macro cell and the distance from the terminal to the small cell is equal to or greater than about 175m, the propagation delay may become greater than the 120kHz SCS CP length (=586 nanoseconds), which may require a signal longer than the cyclic prefix (CP) length between the Pcell and the SCell to compensate for the frame boundary misalignment. Therefore, in order to obtain fine time / frequency synchronization of the SCell, it may not be possible to receive the existing SSB and / or TRS in the SCell, but the existing SSB structure can be modified so that the ES-DRS can be configured as a combination of downlink / uplink signals that are maximally compressed on the time axis. This ES-DRS can be used for terminals to obtain time / frequency synchronization.

[0230] [ES-DRS Structure Example #2-1] ES-DRS can be configured by retaining PSS / SSS in SSB and replacing PBCH symbols with TRS. That is, ES-DRS can have a structure of {PSS+TRS+SSS+TRS}. Here, for PSS / SSS consisting of a 127-length sequence, if the number of guard tones is set to be smaller than the existing SSB, PSS / SSS can be mapped to 11 RPBs.

[0231] In other words, for the first method of configuring ES-DRS, it is possible to consider retaining the current structure of PSS / SSS and replacing the PBCH symbol with TRS. That is, in the above-mentioned SSB structure, {PSS+TRS+SSS+TRS} can be used instead of {PSS+PBCH+SSS+PBCH} configured as a time axis signal. Here, for PSS / SSS consisting of a 127-length sequence, if the number of guard tones is reduced compared to the existing number, the PSS / SSS can be mapped to 11 PRBs. In addition, by considering aspects of the frequency synchronization solution of ES-DRS, a structure with a 4-symbol TRS interval can be implemented in a form such as {beam 1PSS+beam 1TRS+beam 1SSS+beam 2TRS}+{beam 2PSS+beam 1TRS+beam 2SSS+beam 2TRS}. Here, beam indices (such as beam 1 and beam 2) can be replaced by SSB indices, or the same beam indices can be configured (for example, in a QCL relationship).

[0232] [ES-DRS Structure Example #2-2] Similar to RACH, ES-DRS can be configured by designing SSB in the form of {CP+sequence+sequence+…}. For example, structures such as {CP+SSS+SSS+GP} or {CP+TRS+TRS+GP} or {CP+RACH+RACH+GP} are possible. For example, in some cases, the number of repeated sequences may vary depending on the cell radius or the speed of the terminal. Here, in the case of an SSS with a 127-length sequence, the number of guard tones can be set to 11 PRBs, which is less than the number of existing SSBs.

[0233] In other words, similar to RACH, ES-DRS configured in the form of {CP+sequence+sequence+…} can be considered. Currently, the PRACH preamble code is divided into a long sequence (Seq) and a short sequence, and the short sequence of length 139 has the form of {CP+sequence} or {CP+sequence+sequence+…}, such as Fig.19 shown. Fig.19 An example of the format of a synchronous RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated. In addition, according to the format, such as Fig. 20 As shown, format A has the form of {CP+sequence+sequence}, format B has the form of {CP+sequence+sequence+GP}, and format C has the form of {CP+sequence+GP}. Various PRACH preamble code formats are designed to take into account cell size or high-speed scenarios (where the terminal moves quickly), and can be selectively used according to the environment of the terminal and the cell.

[0234] Therefore, similarly, the structure of ES-DRS configured with {CP+SSS+SSS+GP} or {CP+TRS+TRS+GP} or {CP+RACH+RACH+GP} can be considered, and different numbers of repetition sequences can be used depending on the size of the cell or the speed of the terminal. In addition, in this case, by using fewer guard tones than in the existing case, SSS can be mapped to 11 PRBs.

[0235] [ES-DRS Structure Example #2-3] ES-DRS can be configured by a PSS / SSS combination. Structures such as {PSS+PSS+SSS+SSS} or {PSS+SSS+SSS+PSS} are possible. Specifically, ES-DRS can be configured by placing PSS and / or SSS in SSB instead of PBH. When the above-mentioned [ES-DRS Structure Example #2-1] has the form of {PSS+TRS+SSS+TRS}, according to the structure example, ES-DRS can be configured in the form of {PSS+PSS+SSS+SSS} or {PSS+SSS+SSS+PSS}. There may be differences in frequency synchronization between them. For example, in the case of {PSS+SSS+SSS+PSS}, since there are 1-OFDM symbol distance and 3-OFDM symbol distance, the terminal can first obtain synchronization with the 1-OFDM symbol distance, and then reduce the residual error to the 3-OFDM symbol distance, thereby assisting frequency synchronization. Taking this structure into account, simple signaling (e.g., whether the NES mode is turned on / off) is additionally implemented by blind detection (BD) of the terminal in {PSS+PSS+SSS+SSS} and {PSS+PSS+SSS+(-)SSS}. Similarly, in the case of the structure of {PSS+SSS+SSS+PSS}, simple signaling (e.g., whether the NES mode is turned on / off) is implemented by BD of the terminal in {PSS+SSS+SSS+PSS} and {PSS+SSS+(-)SSS+PSS}.

[0236] At the same time, when using the ES-DRS structure based on the above-mentioned PSS / SSS combination, the legacy terminal may malfunction due to the newly added PSS / SSS. Therefore, for legacy terminals, an alternative structure in which only one PSS is placed and only SSS is placed additionally can be considered. For example, ES-DRS structures such as {PSS+SSS+SSS+SSS} can be considered, and it is expected that such a structure has similar performance to [ES-DRS Structure Example #2-1] with respect to frequency synchronization. In addition, in this case, simple signaling (for example, whether the NES mode is turned on / off) is implemented by the terminal in the BD in {PSS+SSS+SSS+SSS} and {PSS+SSS+SSS+(-)SSS}.

[0237] [ES-DRS Structure Example #2-4] In the case where the SSS is repeated, the data signal and SSS can have SCSs with different configurations to reduce the time area occupied by 2 symbols. For example, if the data-SCS is 15kHz, the SSS-SCS can be set to 30kHz, and thus the 2-symbol area of ​​the SSS can be configured the same as the 1-symbol area.

[0238] In other words, in the above structural example, when SSS is repeatedly transmitted, in order to reduce the time area occupied by 2 symbols, the data-SCS can be set to 15kHz, and the SSS-SCS can be set to 30kHz, so that the 2-symbol area of ​​​​the SSS can be configured to have the same time length as the 1-symbol area. In addition, the necessity of TRS may vary according to each terminal, and even when the terminal needs TRS, TRS may not have to be sent as frequently as the SSB cycle. Therefore, such as in [ES-DRS Structure Example #2-2] or [ES-DRS Structure Example #2-3], an ES-DRS structure without TRS can also be used.

[0239] [ES-DRS Structure Example #2-5] ES-DRS can be constructed by multiplexing TRS every K SSB transmissions in ES-DRS. In other words, a structure in which TRS is multiplexed in ES-DRS whenever SSB is repeatedly transmitted K times can be considered. For example, in a structure based on [ES-DRS Structure Example #2-1], TRS can be multiplexed every K SSB transmissions. Alternatively, on the other hand, the period of TRS constituting ES-DRS can be set / transmitted to be shorter than the period of SSB. However, when CA including PCell and SCell is supported, in the case where the terminal is implemented by only one oscillator, this method can be applied to a situation where the time / frequency error only occurs at a predetermined level or lower than PCell.

[0240] According to the wireless communication system disclosed in the present invention, the transmission of various ES-DRS and the operation of associated terminals can be supported by using ES-DRS according to at least one structure or another structure of the above exemplary structures. ES-DRS according to various embodiments can be designed based on SSB for energy saving of base stations. Specifically, when the SSB including the synchronization signal and the TRS is designed as a single unit, the energy consumption of sending SSB and TRS in separate processes, timings or signal groups can be reduced. The specific structure of the ES-DRS applicable to the present invention can be defined in various ways, including the design of retaining the existing SSB structure as shown in [ES-DRS structure example #1] and the design of modifying the existing SSB structure as shown in [ES-DRS structure example #2]. Hereinafter, various embodiments of the use of ES-DRS will be described. In the following description, "ES-DRS" may be referred to as "cell discovery signal", "discovery signal" or any other term with equivalent technical meaning.

[0241] Fig.21 An example of a process for receiving a discovery signal in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.21 A method for operating a terminal is illustrated.

[0242] Reference Fig.21 In step S2101, the terminal receives at least one SSB. The SSB is sent from the base station according to a predefined rule, and the terminal can attempt to receive the SSB based on the rule. That is, the terminal can attempt to detect at least one synchronization signal included in the SSB in a candidate position on the frequency axis of the SSB based on the synchronization grid.

[0243] In step S2103, the terminal obtains synchronization by using a synchronization signal. That is, the terminal can obtain time and / or frequency synchronization with the base station by using the received synchronization signal included in the SSB. By receiving the SSB, the terminal can receive the MIB included in the broadcast channel in addition to the synchronization signal. Therefore, the terminal obtains system information by using the MIB. That is, the terminal can obtain synchronization by using the received SSB, and obtain system information by decoding the MIB mapped to the broadcast channel.

[0244] In step S2105, the terminal performs a random access procedure. The terminal may further obtain different system information (e.g., SIB) based on the system information obtained by using the MIB. In addition, the terminal may identify configuration information related to the random access channel indicated by the different system information, and perform a random access procedure based on the identified configuration information. Specifically, the terminal may send a RACH preamble, receive a random access response message, and perform signaling for connection establishment.

[0245] In step S2107, the terminal sends a message for requesting a discovery signal based on SSB. In other words, the terminal requests the base station to send an ES-DRS including a TRS multiplexed with the SSB or a TRS combined with the SSB. To this end, the terminal may generate a message and / or signal for requesting a discovery signal and send the generated message and / or signal. According to various embodiments, the message and / or signal may include a request for a discovery signal, and may also include at least one of an additional request for the structure of the discovery signal (e.g., bandwidth, periodicity, density, resolution, structure) and an additional request for the transmission time of the discovery signal (e.g., index, index group). Here, at least one additional request may be sent by an explicit indicator, or indicated by selecting a resource for sending a message. The message and / or signal may be generated and sent according to a predefined rule, or may be generated and sent based on the configuration of the base station.

[0246] In step S2109, the terminal performs time and / or frequency tracking by using a discovery signal based on the SSB. According to various embodiments of the present disclosure, the SSB sent from the base station may be multiplexed with a reference signal. Here, the reference signal is used for time and / or frequency tracking and may be referred to as a TRS. Based on the multiplexing scheme, the terminal may determine the position of the reference signal from the position of the SSB and receive the reference signal. By using the reference signal, the terminal may estimate the timing offset, delay spread, frequency offset, and Doppler spread.

[0247] Fig. 22 An example of a process for transmitting a discovery signal in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0248] Reference Fig. 22 , in step S2201, the base station sends an SSB. The base station generates and sends an SSB including at least one synchronization signal and a broadcast channel. Here, the base station may repeatedly send the SSB by using multiple Tx beams. The pattern of resources for sending the SSB may be predefined. In addition, the base station may send system information (e.g., MIB, SIB). The system information may include information related to the random access channel.

[0249] In step S2203, the base station performs a random access procedure for the terminal. Specifically, the base station may perform a random access procedure by receiving a random access preamble through a random access channel indicated by configuration information of the random access channel included in system information (e.g., SIB), sending a random access response, and then performing signaling for connection establishment.

[0250] In step S2205, the base station receives a message for requesting an SSB-based discovery signal from the terminal. In other words, the base station receives a request from the terminal for sending an ES-DRS containing a TRS multiplexed with an SSB or a TRS combined with an SSB. According to various embodiments, the message and / or signal for requesting a discovery signal includes a request for a discovery signal, and may also include a request for a structure of the discovery signal (e.g., bandwidth, periodicity, density, resolution, structure). Here, the message and / or signal may be generated and sent according to a predefined rule, or may be generated and sent based on the configuration of the base station.

[0251] In step S2207, the base station sends a discovery signal based on SSB. In response to a request from the terminal, the base station may send a discovery signal designed based on SSB, i.e., ES-DRS. Here, if multiple discovery signal structures are supported, the base station may select at least one structure and then send a discovery signal in the selected structure. For example, the base station may accept the structure requested by the terminal, or select at least one structure based on current resource usage and / or available energy conditions.

[0252] Despite Fig. 22 Although not shown in the figure, before sending the discovery signal, the base station may send configuration information related to the discovery signal. Therefore, the base station may notify the terminal of the configuration of the discovery signal, such as the structure and index, and the terminal may attempt to receive the discovery signal based on the configuration information.

[0253] According to reference Fig.21 and Fig. 22 In the described embodiment, the terminal may request the base station to send a discovery signal. In the above embodiment, the terminal requests the sending of the discovery signal after the random access process. However, according to another embodiment, the terminal may request the sending of the discovery signal before the random access process. In this case, the terminal can perform synchronization for the random access process by using the discovery signal.

[0254] According to various embodiments, the base station may provide a plurality of cells (e.g., Pcell, Scell) to the terminal. Here, according to the embodiment, the transmission and reception of SSB and the random access process may be performed in the Pcell, and the subsequent transmission and reception of the discovery signal may be performed in the Scell. That is, the SSB may be used for synchronization in the Pcell, and the discovery signal may be used for synchronization in the Scell.

[0255] Alternatively, according to another embodiment, the transmission and reception of SSB and the random access process and the transmission and reception of subsequent discovery signals can all be performed in the same cell. In this case, initial synchronization can be performed by using SSB, and additional synchronization and measurement can be performed by using discovery signals.

[0256] Fig.23 An example of a process for requesting and transmitting a discovery signal in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.23 Signal exchange between terminal 2310 and base station 2320 is illustrated.

[0257] Reference Fig.23 In step S2301, the base station 2320 sends allocation information of an uplink signal and / or channel for requesting ES-DRS to the terminal 2310. For example, the base station 2320 may configure resources of an uplink signal and / or channel defined for ES-DRS request for the terminal by using high-layer signaling such as RRC signaling. For example, the RRC signaling may be dedicated signaling or include system information.

[0258] In step S2303, the terminal 2310 transmits an uplink signal and / or channel in the resources allocated for requesting ES-DRS to the base station 2320. That is, the terminal 2310 may transmit an uplink signal and / or signal configured in the resources allocated for the ES-DRS request.

[0259] In step S2305, the terminal 2310 receives the DS-DRS and obtains time and / or frequency axis synchronization. By receiving the ES-DRS, the terminal 2310 can obtain time and / or frequency axis synchronization of the serving cell configured by the base station 2320, and thus perform efficient data transmission and reception. In addition, the base station can save energy by transmitting the aggregated ES-DRS on the time axis.

[0260] [Implementation method #1] Method for a base station to send ES-DRS upon request of a terminal

[0261] The base station may not send ES-DRS for a certain service cell (e.g., P(S)Cell, SCell), but perform power saving operations. Here, the terminal may need to receive ES-DRS to obtain time axis and / or frequency axis synchronization of the cell. To this end, the base station may predefine and / or configure resources for uplink signals / channels (e.g., SRS, PRACH, PUCCH, scheduling request (SR), etc.), and the terminal may expect to receive ES-DRS in the service cell by sending uplink signals / channels via the resources.

[0262] Specifically, when the terminal operates in an activated SCell, the terminal can receive information related to the transmissibility of ES-DRS in the cell from the base station, and can allocate an uplink signal / channel capable of requesting ES-DRS. The resources of the uplink signal / channel can be in the P(S)Cell (e.g., SCell or another SCell) where uplink transmission is activated, and which cell is available can be configured and / or indicated from the base station. As an example, a specific RACH opportunity (RO), a PRACH preamble index, an SR resource, a PUSCH resource, or a PUCCH resource can be used for an ES-DRS request, and the ES-DRS request information can be sent as an incidental form on the PUSCH.

[0263] In addition, resources can be configured according to each index corresponding to the ES-DRS or each such index group. For example, information about the index or index group can be included in different ROs, different PRACH preamble indexes, different SR resources, or different PUCCH / PUSCH payloads. Here, each index can correspond to QCL type-D of the ES-DRS.

[0264] In addition, in the case where the configuration of ES-DRS is defined in various ways, information about the signal configuration (for example, in [ES-DRS structure example #2], which combination of PSS / SSS will configure ES-DRS, or how many times the sequence part will be repeated to configure ES-DRS) can be determined according to which information or resource the terminal selects among the configured resources (for example, ES-DRS configuration information can be included in different ROs, different PRACH preamble indexes, different SR resources, or PUCCH / PUSCH payloads). In other words, the terminal can send a signal for requesting ES-DRS through a resource corresponding to the configuration of the ES-DRS to be requested.

[0265] In addition, after the terminal sends an uplink signal / channel for an ES-DRS request, it may be necessary to define the initial ES-DRS reception time expected by the terminal. If the ES-DRS candidate timing is predefined or configured, the initial ES-DRS candidate timing after T1 milliseconds or time slots after the uplink signal / channel transmission time for the ES-DRS request can be determined as the initial ES-DRS reception time expected by the terminal. Here, the value of T1 can be predefined or set to a specific value by the base station.

[0266] [Implementation #2] Method for determining PDSCH reception availability including resources and slot format indicators of ES-DRS bursts

[0267] When a terminal is scheduled with a PDSCH in a certain service cell through a PDCCH scrambled by a CRC based on a specific RNTI (e.g., C-RNTI), the PDSCH may overlap with an ES-DRS with a specific index. In this case, when the terminal receives the PDSCH, it may be necessary to consider the resources overlapping with the ES-DRS.

[0268] To this end, according to an embodiment, the base station may configure and / or indicate that it is performing transmission for a specific ES-DRS index in the serving cell. When the configuration and / or indication is received, the terminal may determine that the RB area overlapping with the ES-DRS in the OFDM symbol in which the ES-DRS is transmitted makes the mapping of the corresponding PDSCH (i.e., the PDSCH scheduled in the serving cell by the PDCCH scrambled by the CRC based on a specific RNTI (e.g., C-RNTI)) unavailable. Therefore, when receiving the PDSCH, the terminal may perform a rate matching operation on the area overlapping with the ES-DRS. That is, when information about at least one index of the ES-DRS is being sent from the base station, and a downlink resource (e.g., PDSCH) having an area at least partially overlapping with the resources occupied by the ES-DRS determined by the at least one index is allocated, the terminal performs a rate matching operation on at least the partially overlapping area.

[0269] In addition, when receiving a configuration and / or indication of ongoing transmission of a specific ES-DRS index in the corresponding service cell from the base station, the terminal may not expect to configure the OFDM symbol and / or RB area for sending the corresponding ES-DRS (for example, by using high-layer signaling of tdd-UL-DL-ConfigurationCommo or tdd-UL-DL-ConfigurationDedicated) or indicate (for example, through DCI format 2_0) as uplink. In addition, when receiving a configuration and / or indication of ongoing transmission for a specific ES-DRS index in the corresponding service cell from the base station, the terminal may not send PUSCH / PUCCH / PRACH / SRS in the OFDM symbol and / or RB area for sending the corresponding ES-DRS. That is, the terminal can determine not to perform uplink transmission in the OFDM symbol and / or RB area for sending ES-DRS, in other words, exclude uplink transmission.

[0270] [Implementation #3] Mapping method of ES-DRS and RACH timing (RO) or PUSCH timing (PO)

[0271] By reusing the rules of SSB to RO mapping and / or SSB to PO mapping as shown in Table 8, the mapping relationship between ES-DRS index and RO and / or PO can be defined. In the following, for ease of description, RO will be described, but the same mapping relationship can also be applied to PO. Table 8 is excerpted from TS 38.213v17.3.0 on random access preamble.

[0272] [Table 8]

[0273]

[0274]

[0275]

[0276]

[0277]

[0278]

[0279]

[0280] As in [Implementation #1], whether a particular ES-DRS index is sent may vary over time based on a request by a terminal or a determination by a base station. When the ES-DRS index corresponding to a particular RO keeps changing due to such a change, the terminal may be ambiguous about which ES-DRS index corresponds to the RO. In order to reduce such ambiguity, it may be desirable to minimize changes in the mapping relationship between the RO and the corresponding ES-DRS index, even if the ES-DRS index being sent changes.

[0281] For example, in the case where RO mapping is initially performed based on ES-DRS index 0 / 2 / 5, ES-DRS index 1 may be additionally transmitted. In this case, the ES-DRS index may not be rearranged to 0 / 1 / 2 / 5 to perform RO mapping, but the ES-DRS index 1 that has begun to be transmitted may be placed at the end, and thus the RO mapping may be performed in the order of 0 / 2 / 5 / 1. That is, the base station and the terminal may determine the mapping between the ES-DRS and the RO so that the RO corresponding to the added ES-DRS index is not placed in the middle of the RO of the currently transmitted ES-DRS index, but is placed at the end after them. This method may be advantageous in reducing ambiguity.

[0282] Similarly, for example, a situation may occur where PO mapping is initially performed based on ES-DRS index 0 / 2 / 5 and then ES-DRS index 1 is additionally transmitted. In this case, the ES-DRS index may not be rearranged to 0 / 1 / 2 / 5 to perform PO mapping, but the ES-DRS index 1 that has already begun to be transmitted may be placed at the end, and thus PO mapping may be performed in the order of 0 / 2 / 5 / 1. That is, the base station and the terminal may determine the mapping between ES-DRS and PO so that the PO corresponding to the added ES-DRS index is not placed in the middle of the PO of the currently transmitted ES-DRS index, but is placed at the end after them. This method may be advantageous in reducing ambiguity.

[0283] As another example, it can be defined that the number of ES-DRS indexes between the terminal and the base station is limited to a maximum of 4, and RO mapping can be performed first for ES-DRS indexes X / Y / Z / W. Here, X, Y, Z, and W are virtual ES-DRS indexes. If the terminal perceives that ES-DRS index 0 / 4 is being sent, X and Y can be set to 0 and 4 (X=0, Y=4), respectively, and the terminal can consider the RO corresponding to ES-DRS index Z / W to be invalid. Next, when the terminal perceives that ES-DRS index 3 is being sent, ES-DRS index Z can be set to 3 (Z=3), and the terminal can consider the RO corresponding to ES-DRS index W to be invalid. Next, when the terminal perceives that the transmission of ES-DRS index 0 is suspended, the terminal can consider the RO corresponding to ES-DRS index X / W to be invalid.

[0284] Similarly, it can be defined that the number of ES-DRS indexes between the terminal and the base station is limited to a maximum of 4, and PO mapping can be performed first for ES-DRS indexes X / Y / Z / W. Here, X, Y, Z, and W are virtual ES-DRS indexes. If the terminal perceives that ES-DRS index 0 / 4 is being sent, X and Y can be set to 0 and 4 (X=0, Y=4), respectively, and the terminal can consider the PO corresponding to ES-DRS index Z / W to be invalid. Next, when the terminal perceives that ES-DRS index 3 is being sent, ES-DRS index Z can be set to 3 (Z=3), and the terminal can consider the PO corresponding to ES-DRS index W to be invalid. Next, when the terminal perceives that the transmission of ES-DRS index 0 is suspended, the terminal can consider the PO corresponding to ES-DRS index X / W to be invalid.

[0285] [Implementation #4] Method for transmitting / receiving ES-DRS in an unlicensed band

[0286] As shown in Table 9, SSB transmission and reception in unlicensed band operation and / or shared spectrum channel access operation are defined. If the serving cell that sends ES-DRS operates based on unlicensed band operation, a transmission window in which ES-DRS can be sent can be defined, and multiple transmission opportunities need to be provided in the window. Table 9 is an excerpt from TS38.213v17.3.0, describing unlicensed band operation and / or shared spectrum channel access operation.

[0287] [Table 9]

[0288]

[0289]

[0290] Specifically, the ES-DRS candidate index that can be sent within the ES-DRS transmission window can be determined. For example, the candidate index can be determined based on a combination of a sequence of symbols and / or a payload constituting the ES-DRS. In addition, similar to Parameters can be used to configure how many ES-DRS candidate index intervals satisfy the QCL relationship. In the present disclosure, the ES-DRS candidate index interval that satisfies the QCL relationship is referred to as N_QCL. The terminal can perceive that the ES-DSR candidate indexes with the same result of the modulus operation with N_QCL are in the QCL relationship and correspond to the same ES-DRS index.

[0291] In addition, in the case where multiple ES-DRS candidate indexes correspond to one ES-DRS index, the proposed method of [Implementation #2] can be commonly applied to all of the multiple ES-DRS candidate indexes corresponding to the specific ES-DRS index.

[0292] [Implementation #5] Method for providing a configuration with various functions through ES-DRS

[0293] ES-DRS or an index of ES-DRS may be configured in the terminal for the purpose described below. For example, the function configured according to this embodiment may include at least a portion of the function that can be configured in the existing SSB / CSI-RS. At least one of the following configurations may be applied to a terminal capable of receiving ES-DRS.

[0294] - L1 (e.g., L1-RSRP / SINR) or L3 RRM / RSRP / RSRQ measurements

[0295] -CSI measurement

[0296] -Beam Failure Detection (BFD)

[0297] -Candidate Beam Detection (CBD)

[0298] -QCL source RS in TCI state

[0299] - RS interoperating with SpatialRelationInfo configuration for uplink channels / signals

[0300] -Configuration of ES-DRS index instead of CSI-RS for fast SCell activation, as shown in Table 10

[0301] -Configuration for receiving ES-DRS instead of TRS in idle / inactive terminals. For example, ES-DRS reception resources may be allocated to corresponding terminals via a broadcast channel.

[0302] At least one of the above items may be indicated by at least one of the location of the resource to which the ES-DRS is mapped, the index of the ES-DRS, the sequence value of the signal included in the ES-DRS, and the structure of the ES-DRS. Table 10 is extracted from TS38.214v17.3.0 regarding non-periodic C.

[0303] [Table 10]

[0304]

[0305] As shown in the various embodiments described above, ES-DRS (which is a set of signals sent from a base station) can be used to obtain time / frequency synchronization of a serving cell. The present disclosure has proposed a process for requesting ES-DRS and operations of a terminal associated with receiving the signal. Therefore, efficient transmission and reception of ES-DRS can be supported, power consumption of the terminal can be reduced, and energy consumed by the base station to provide the signal required for the process of the terminal obtaining synchronization can also be reduced.

[0306] The example of the above-mentioned proposed method may be included as one of the implementation methods of the present disclosure, and thus may be regarded as a type of the proposed method. In addition, the above-mentioned proposed method may be implemented independently, or some of the proposed methods may be combined (or merged). The rule may be defined so that the base station notifies the UE of information on whether to apply the proposed method (or information about the rule of the proposed method) through a predefined signal (e.g., a physical layer signal or a higher layer signal).

[0307] Those skilled in the art will appreciate that the present disclosure can be implemented in other specific ways than those described herein without departing from the spirit and essential characteristics of the present disclosure. Therefore, the above exemplary embodiments should be interpreted in all respects as illustrative and not restrictive. The scope of the present disclosure should be determined by the appended claims and their legal equivalents, rather than by the above description, and it is intended that all changes that come within the meaning and equivalent range of the appended claims are covered therein. In addition, it will be apparent that some claims that refer to specific claims can be combined with another claim that refers to other claims other than the specific claims to constitute an embodiment, or new claims can be added by amendment after the application is submitted.

[0308] Industrial Applicability

[0309] Embodiments of the present disclosure are applicable to various radio access systems. Examples of various radio access systems include the 3rd Generation Partnership Project (3GPP) or 3GPP2 system.

[0310] The embodiments of the present disclosure are applicable not only to various radio access systems but also to all technical fields to which various radio access systems are applied. In addition, the proposed method is applicable to millimeter wave and terahertz wave communication systems using ultra-high frequency bands.

[0311] Additionally, embodiments of the present disclosure are applicable to a variety of applications, such as autonomous vehicles, drones, and the like.

Claims

1. A method for operating a terminal in a wireless communication system, the method comprising: receiving at least one synchronization signal and a broadcast channel block SSB; obtaining synchronization with a base station by using a synchronization signal included in said SSB; Obtaining system information based on a master information block MIB included in the SSB; performing a random access procedure based on the system information; Sending a message for requesting to send a discovery signal based on an SSB to the base station; as well as Tracking for at least one of time and frequency is performed based on the discovery signal.

2. The method according to claim 1, wherein: receiving the at least one SSB in a primary cell provided by the base station, and The discovery signal is received in a secondary cell provided by the base station.

3. The method according to claim 1, wherein: The discovery signal has a structure including at least one multiplexed synchronization signal, at least one broadcast channel and at least one reference signal, or has a structure including at least one of multiple synchronization signals, at least one reference signal, at least one cyclic prefix and at least one guard period GP.

4. The method according to claim 1, further comprising: Information about uplink resources used to send the message is received.

5. The method according to claim 4, wherein: The uplink resource includes at least one of a random access channel RACH opportunity RO, a RACH preamble code index, a scheduling request SR resource, a physical uplink shared channel PUSCH resource or a physical uplink control channel PUCCH resource.

6. The method according to claim 1, wherein: The message includes a request for at least one of: a structure of the discovery signal, an index of the discovery signal, or an index group of the discovery signal.

7. The method according to claim 1, wherein: The discovery signal is received after a predefined time interval has elapsed since the sending of the message.

8. The method according to claim 1, further comprising: receiving information about at least one index of the transmitted discovery signal; as well as Based on the allocation of downlink resources having a region at least partially overlapping with the resources occupied by the discovery signal determined by the at least one index, a rate matching operation is performed on the at least partially overlapping region.

9. The method according to claim 1, further comprising: receiving information about at least one index of the transmitted discovery signal; as well as It is determined to exclude uplink transmission from resources occupied by the discovery signal determined by the at least one index.

10. The method according to claim 1, further comprising: receiving information indicating adding an index of a sent discovery signal; as well as The mapping between the discovery signal and the RACH opportunity RO or the physical uplink shared channel opportunity PO is determined so that the RO or PO corresponding to the index is placed after at least one RO or PO corresponding to at least one index of at least one discovery signal currently being sent.

11. The method according to claim 1, wherein: The discovery signal indicates a configuration related to at least one of the following items by using at least one of a mapping position, an index, a sequence value, and a structure: layer 1 L1 measurement, layer 3 L3 measurement, channel state information CSI measurement, beam failure detection BFD, candidate beam detection CBD, a quasi-co-site QCL source reference signal for a TCI state, a reference signal interoperable with the configuration of a SpatialRelationInfo for an uplink signal, an ES-DRS index configuration for fast SCell activation instead of CSI-RS, and reception of ES-DRS instead of TRS in an idle or inactive terminal.

12. A method for operating a base station in a wireless communication system, the method comprising: Sending at least one synchronization signal and a broadcast channel block SSB; Sending system information related to random access channel; performing a random access procedure based on the system information; receiving a message for requesting the base station to send a discovery signal based on an SSB; as well as The discovery signal is sent.

13. The method according to claim 12, further comprising: Information about uplink resources used to send the message is sent.

14. The method according to claim 12, further comprising: Configuration information including at least one of a structure and an index of the discovery signal is transmitted.

15. A terminal in a wireless communication system, the terminal comprising: Transceiver; as well as a processor coupled to the transceiver, Wherein, the processor is configured to: receiving at least one synchronization signal and a broadcast channel block SSB; obtaining synchronization with a base station by using a synchronization signal included in said SSB; Obtaining system information based on a master information block MIB included in the SSB; performing a random access procedure based on the system information; sending a message for requesting to send a discovery signal based on an SSB to the base station; and Tracking for at least one of time and frequency is performed based on the discovery signal.

16. A base station in a wireless communication system, the base station comprising: Transceiver; as well as a processor coupled to the transceiver, Wherein, the processor is configured to: Sending at least one synchronization signal and a broadcast channel block SSB; Sending system information related to random access channel; performing a random access procedure based on the system information; receiving a message for requesting the base station to send a discovery signal based on an SSB; and The discovery signal is sent.

17. A communication device, comprising: at least one processor; as well as at least one computer memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, indicate operations, The operations include: receiving at least one synchronization signal and a broadcast channel block SSB; obtaining synchronization with a base station by using a synchronization signal included in said SSB; Obtaining system information based on a master information block MIB included in the SSB; performing a random access procedure based on the system information; sending a message for requesting to send a discovery signal based on an SSB to the base station; and Tracking for at least one of time and frequency is performed based on the discovery signal.

18. A non-transitory computer-readable medium storing at least one instruction, the non-transitory computer-readable medium comprising the at least one instruction executable by a processor, in, The at least one instruction controls the device to: receiving at least one synchronization signal and a broadcast channel block SSB; obtaining synchronization with a base station by using a synchronization signal included in said SSB; Obtaining system information based on a master information block MIB included in the SSB; performing a random access procedure based on the system information; Sending a message for requesting to send a discovery signal based on an SSB to the base station; as well as Tracking for at least one of time and frequency is performed based on the discovery signal.

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